DE2001286A1 - Process for the impregnation of porous objects - Google Patents

Description

20Q1266

January 13, 1970 Case 44

I.0CT1TE CORPORATION
Newington, Connecticut, V.St.A.

Process for impregnating porous objects

Bulky objects can be sealed and impregnated without heat curing be done by (1) the object with the anaerobic Combination of an acrylate monomer and a redox catalyst system impregnated; and (2) following the impregnation stage treating the impregnated article with an accelerator for free radical polymerization.

Porous, rigid objects and in particular porous metal objects, such as castings and sintered metal parts, must often be sealed and impregnated before use (for the sake of simplicity, the term "sealed ¹ " is generally used below). This is necessary in order to make the object to make it resistant to liquid or gas pressure in use and also to increase its density, improve its strength, reduce corrosion and often to prepare the surface of the article for a subsequent painting or plating operation. A wide variety of porous metal articles is used in technology today and is made from a wide variety of metals, although zinc, copper, brass and various alloys are not uncommon

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are by far the most important starting materials aluminum and iron. Other typical materials that often need to be sealed are wood and ceramic materials. in the The prior art clearly recognized the need for these articles to be sealed for many years. Pas earliest sealing methods generally concerned use either an inorganic sealant such as sodium silicate or a natural organic substance such as varnish. Recently, substances such as unsaturated alkyds, epoxies and various other unsaturated monomers such as diallyl phthalate have been used. See, for example, U.S. Patents 3,345,205 and 2,554,254 and 2,932,583.

To date, this is still not a really satisfactory process has been developed. After treatment by most of the prior art methods, significant percentages of the treated articles were found to be inadequately sealed. In addition, a fully acceptable impregnation process has not been developed that does not use a press cycle would have been necessary during the impregnation operation and a high temperature drying or either or a curing cycle after the impregnation step. Efforts have been made to eliminate the press cycle and this has resulted however, an undesirably high percentage of inadequately sealed articles.

Efforts have also been made to eliminate the need for thermosetting by using a "catalyzed ¹¹ impregnant. For example, a low viscosity epoxy monomer can be mixed with a hardener therefor and the mixture used as an impregnant. Or an unsaturated monomer from "Vinyl type" such as diallyl phthalate can be mixed with a peroxide and the combination used as an impregnating agent Unfortunately, the uses of catalyzed impregnating agents have been different

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Disadvantages inherent. If the impregnation agent is sufficiently active, so that it cures without a heating period, the curing rate at normal impregnation temperatures is such that the useful life of the impregnant is relatively short; the viscosity of the impregnating agent increases with the progression Hardening, which creates constant changes in the impregnation ability. Conversely, if less active Impregnants are used to eliminate viscosity changes, heat curing is required.

Furthermore, there were objects that were made by processes and with impregnating agents prior art had been impregnated, generally a surface treatment after the impregnation, like painting or plating, not adjusted well enough. When the impregnated item is treated with a cleaning solution is used to remove the impregnant from the surface of the article, so much of the impregnant becomes from the surface pores of the object leached out that microscopic depressions remain on the whole OOj surface, which in turn an unsatisfactorily rough, holey surface produced in the subsequent surface treatment. Close this hole also include, for example, plating acids or paint solvents, which usually destroy the desired surface finish.

On the other hand, if the impregnant is left on the surface of the articles until after the hardening operation, both the impregnant on the surface and the impregnant in the pores will be hardened and grinding, polishing or strong chemical action will be required to to clean the surface of the object. Such operations have an unfavorable influence on the surface properties or tolerances of the objects and? ^r also extremely time-consuming and arduous work.

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BATH ORIGINAL

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The purpose of the present invention is to create a method which is not burdened with the above-described problems which plagued the known methods, and in particular to provide a method of impregnating porous, rigid articles that does not involve the use of pressure impregnation cycles or heat setting operations are required, and which directly creates a surface suitable for painting or plating.

The method of the present invention relates to impregnation rigid, porous objects with an anaerobic impregnant and subsequent treatment of the surface of the impregnated object with a polymerization accelerator for the impregnating agent used. Usually the impregnation carried out by applying a vacuum period, with the interstices of the porous objects with the help of a Vacuum, e.g., a vacuum of about 12.70 cm (5 inches) absolute Mercury pressure, whereupon the objects are treated with the impregnating agent. When the In a vacuum, the impregnating agent is drawn into the gaps (gaps, gaps) of the object. Where it is convenient the polymerization accelerator is generally dissolved in a solvent in order to facilitate handling and to reduce the To achieve cleaning of the surface of the impregnated object.

A typical process using the inventive method disclosed herein Concept is represented by the following stages:

a) The porous metal article is subjected to a vacuum, such as an absolute pressure of less than about 12.70 om (5 inches) of mercury to substantially evacuate the interstices of the object;

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b) after the gaps (gaps, crevices) of the object have been appropriately evacuated, the object is treated with the impregnating agent, for example by placing it in the Submerged waterproofing agent;

o) the vacuum is released while the article is still in contact with the impregnating agent; and

d) the surface of the impregnated metal object becomes the Subjected to the action of a polymerization accelerator for the impregnating agent by, for example, a solution of the accelerator is sprayed in a solvent or the parts are immersed in a solution of the accelerator. '

The procedure described here can be used successfully for impregnation various porous, rigid objects can be used. (The word "rigid" as used here is intended to refer to relative Inflexible and gas-impermeable materials, in contrast to flexible, permeable materials such as rubber, Fabrics, fiber material etc.). However, the present invention will hereinafter be described generally with reference to metal articles described, since in this field of application the process is particularly useful and offers exceptional advantages.

(A) The pieces of metal

The basic nature of the porous metal articles to be impregnated and sealed as described herein is not a critical element of the present invention. Porous metal articles are made by various methods known in the art and essentially all of them can be successfully impregnated using the present invention.

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The first of the two usual methods of manufacturing such objects is the casting process, with one molten Metal poured into a preformed form (generally made from sand or other high temperature resistant material) | becomes where the molten metal is allowed to get feet. Objects of this type often have minor imperfections and pores, particularly in the vicinity of the surface of the casting. The second of the usual methods of making the one in question here standing metal objects consists in the sintering of powder preformed metal pieces. This process generally involves pressing a mass of fine, metallic particles into a predetermined shape or configuration and then sintering the pressed part at a temperature in the vicinity of the Melting point of the metal used so that the different particles can fuse. With certain Applications it is possible to dispense with the requirement of sintering, such as where there is low strength in the finished product Product is acceptable or desirable. Sintered metal type materials generally occupy a relatively uniform system of pores or spaces throughout Object through.

The most common metals used to make metal parts Used by casting or sintering are copper, zinc, aluminum, various alloys of these three metals (especially brass) and iron. Porous items made from all of these Metals can be sealed successfully using the invention described herein. Also less frequently used metals, such as various steels, including stainless steels, Silver, platinum, chrome and tin can be sealed using the present method

In general, the maximum pore size in the porous objects should be about 50 μ (about 0.002 "). With larger pores

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the structural integrity of the object is called into question and sealing is more difficult. By increasing the viscosity of the impregnating agent, however, porous objects "which have larger pores" can also be successfully sealed if the requirements for the sealed object are not too high. It was found that with the process of the present invention, a porosity of up to about 150 μ (about 0.006 ^M) can be successfully sealed.

(B) Da3 impregnation agent

The impregnating agents used in the method of the present invention are anaerobic sealing compositions. Oxygen inhibits the polymerization of certain unsaturated monomers, thus enabling them to take place well ahead of time of intended use to catalyze. As long as the mixture of monomer and catalyst is properly exposed to the oxygen does not take place for extended periods of time, usually several months and in many cases for more than a year Polymerization takes place. lifter ° naeroben, (essentially oxygen pure) "conditions, however, is the delicate balance between initiation and inhibition of the polymerization is disturbed and the composition begins to harden. Anaerobic conditions can be reached inside the porous metal parts if they are treated according to the invention described here.

The most desirable monomers for use in anaerobic systems are polymerizable acrylate esters. When using in the experienced According to the present invention, at least a portion of the monomeric acrylate is preferably a di- or another polyacrylate ester. These polyfunctional monomers produce cross-linked po- ' lymerisate that serve as a more effective and permanent sealant to serve.

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Most preferred acrylate esters, those in those described herein Compositions that can be used are polyaorylate esters of the following general formula:

(1) 0

H ₉ C = CCO ε ²

/ β ¹ ^ - R ¹ C. P. C-O
A ¹ \ /

- C-Cr = CH

ι ο

in which R is hydrogen, lower alkyl of 1 to about 4 carbon atoms, hydroxyalkyl of 1 to about 4 carbon atoms, or

0
-CH ₂ -OCC = CH ₂

means,

R is hydrogen, halogen, or lower alkyl of 1 to about 4 carbon atoms;

R * hydrogen, hydroxyl or

0 -0-CC = CH ₀

means;

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m is an integer of at least 1, for example from 1 to about 15 or more and preferably from 1 to about 8 including;

η is an integer of at least 1, e.g. * from 1 to about 20 or more, and preferably between about 2 and about 6; and

ρ means 0 or 1.

As examples of the polymerizable polyacrylate esters that can be used according to the invention and the above general Formula correspond to the following materials may be mentioned, but without being limited to them: Di-, tri- and tetraethylene glycol dimethacrylate; Dipropylene glycol dimethacrylate; Polyethylene glycol dimethacrylate; Di (pentamethylene glycol) dimethacrylate; tetraethylene glycol diacrylate j tetraethylene glycol di (chloroacrylate); Diglycerol diacrylate; Diglycerin tetramethacrylate; Tetramethylene dimethacrylate; Ethylene dimethacrylate; Neopentyl glycol diacrylate and trimethylolpropane triacrylate.

Although polyacrylate esters - and in particular the polyacrylate esters described in the previous sections - have proven to be particularly desirable, monofunctional aorylate esters (esters which contain only one acrylate group) can also be used.

The most common of these monofunctional esters are the alkyl ethers, such as methyl methacrylate, ethyl methacrylate , propyl methacrylate and isobutyl methacrylate. Many of these lower molecular weight alkyl esters are quite volatile and it is often more desirable to use a higher molecular weight homolog such as decyl methaorylate or sodecyl methaorylate.

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When dealing with monofunctional acrylate esters, it is preferred to use an ester with a relatively polar alcoholic part. Such materials are less volatile than alkyl esters of lower molecular weight and, in addition, the polar group tends to develop intermolecular attractive forces in the cured polymer, which results in a more permanent seal. The most preferred polar group is selected from the following polar groups: labile hydrogen, heterocyclic ring, hydroxy, amino, cyano and halogen. Typical examples of compounds in this category are cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl aylate, hydroxypropyl methacrylate, t-butylaminoethyl methacrylate, cyanoethyl acrylate and chloroethyl methacrylate.

Other acrylates can also be used in the impregnation system will. However, when other acrylates are used, it is preferred to use them in combination with one or more Subdivide either or both of the classes of acrylate monomers described above. Most preferably contain the Polyacrylates of the chemical formula (1) given above, at least about 50% by weight of the acrylates used, as these monomers clearly superior in anaerobic sealants, as discussed in more detail below will.

As mentioned above, a particular advantage of the impregnation system described here is that it is a catalyzed system that is capable of curing at room temperature and still provides excellent control of the viscosity of the uncured sealant. Rarely, if ever, the viscosity of the sealant to ■ take ore to than twice, even if it after Katalysi e tion 6 months or allowed to stand for long. ■ In general, the increase is not aoht under these conditions more than 25

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up to 50 i » . The viscosity of the sealant at the time of catalyzing is generally about 1 to about 1000 centipoise, preferably between about 5 and about 500 centipoise. The most preferred range is from about 5 to about 150 centipoise. Viscosities higher than the specified make penetration of the sealant into the porous part difficult or impossible; Extremely low viscosity sealants tend to leak from the part following penetration. The surface tension of the sealant may also affect these properties, however, a viscosity control seems to be the \ important factor. The ideal viscosity of a sealant is a function of the pore size of the porous part to be impregnated and can easily be determined with just a few routine tests. *

The above-described monomers are given anaerobic properties by incorporating a suitable polymerization initiator system into them. In the practical absence of oxygen, the initiator must be able to induce polymerization of the monomer or monomers and yet remain unable to induce polymerization so long as oxygen is present. As the unsaturated monomer used as an impregnant in the vorlie- λ constricting invention are conveniently cured by a mechanism which proceeds via free radical, is the most common initiator system, a redox polymerization initiator, ie, an additive or a combination tion of additives which an oxidation -Cause reduction reaction, which leads to the formation of free radicals. The most common InitiatorByeteiEe this type are to include those who Peroxydmaterielien, in ⁴ · He disintegrate the appropriate conditions to form free Peroxyrad kaien! The.

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A class of peroxy initiators that are proven to be anaerobic Easily adaptable concept and proven to be particularly effective when used in combination with the acrylate monomers described above are the hydroperoxy initiators. From this bottle lake are the organic hydroperoxides and compounds such as peracids and peresters that form organic hydroperoxides hydrolyze or disintegrate, the most preferred. Cumene hydroperoxide has been used with particular success been.

The hydroperoxide initiators are very efficient when used in the impregnation system described here, as many of the metal objects that are to be impregnated with the hydroperoxides to form a powerful Redox polymerization initiator cooperate. In the presence of many metals, the decomposition rate of the hydroperoxides increases with the formation of free radicals greatly increased, whereby a rapid hardening of the monomer is effected when the inhibiting The effect of oxygen is absent. For the sake of versatility, it is often desirable to add one more to the impregnating agent Incorporate ingredient to complete the redox initiator system and thus to eliminate the dependence on the nature of the object to be impregnated. For example, fall different classes of accelerators with hydroperoxide decomposition in this category. Typical examples are tertiary amines, such as tributylamine, sulfimides, such as benzoic acid sulfimide, formamide and compounds containing transition metals such as copper octanoate.

Although the amount of redox polymerization initiator in the impregnant can vary within wide limits, it is for one such initiator impractical, more than about 10 wt .-% Imprägniermitteig can be identified and he preferably does not

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greater than about 5 weight percent of the impregnant. Most preferred the redox polymerization initiator makes about 0.2 # to about 2 wt .- ^ of the impregnating agent. The weight percent ate of the redox polymer initiator in the impregnating agent should not be allowed to drop below about 0.1 #, since below this level the curing of the impregnation agent is inadequate runs slowly.

When the second component of the peroxidic redox syoteme is added together with the peroxidic material to the impregnating agent, the weight ratio of these components vary considerably depending on the particular materials chosen and the nature of their interaction. In the Hegel however, the ratio of peroxidic material to the second component is from about 1: 0.001 to about 1: 1. The most effective Balance between the two components can easily be determined with just a few routine tests.

ι a

A particularly desirable method of incorporating the redox initiator system into an impregnating agent which contains an acrylate monomer with at least one ether bond (such as the monomers of formula 1, above, where η is greater than 1), consists in subjecting the impregnating agent composition to oxygenation. This is generally achieved by continuously bubbling oxygen (pure oxygen, air, ozone) through the acrylate monomer or monomers. As a direct result of this, anaerobic properties are imparted to the monomeric composition. It is believed, is that a portion of the oxygen with part of the monomers combined to form "native" hydroperoxides on the monomers. Polymerization due to this native hydroperoxide content is inhibited by non-combined oxygen and the composition therefore does not polymerize as long as oxygenation is continued. This system is better because one

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single substance (oxygen) serves both to initiate and to stabilize the impregnating agent. It turned out to be a small amount of hydroperoxide, previously oxygenated acrylate monomer, or some other accelerator proved desirable to incorporate native hydroperoxide formation into the impregnating agent before the start of oxygenation. It was found, that this shortens the activation period, e.g., the period required to give the impregnant the curing ability in the absence of oxygen. Systems of this type are discussed in more detail in U.S. Patent 2,628,178.

In the oxygenated system, oxygenation should continue until the "active oxygen content" (as in the next Paragraph described) reaches a suitably high value to ensure a reasonably rapid polymerization of the impregnation agent, once it has been drawn into the porous metal object. Generally this level is about 0.1 wt .- # of the impregnating agent. In practice, the active oxygen content should not be about 5% by weight of the impregnant exceed. Ee has been found to be the most desirable Ranges from about 0.2 to about 1.0 weight percent of the impregnating agent lies.

The active oxygen content can be according to that mentioned in the above US patent specification can be determined as follows. About 0.01 to about 0.05 g of the oxygenated monomer are weighed into a flask and about 10 ml of glacial acetic acid and a small piece of dry ice are added. After this enough dry ice has evaporated to remove the oxygen from the. To displace the flask, about 1 ml of a saturated aqueous Potassium iodide solution stirred into the above ingredients. Using a looker-seated plug to remove the inert at-

-U-

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To preserve moephare, the mixture is in for about 15 minutes heated in an oven at 60 ° C. After removing the flask from the oven, about 10 ml of water are added, and the warm The solution is titrated immediately with about 0.1N sodium thiosulphate, using the disappearance of iodine color as the endpoint. The active oxygen content can then be according to the following Formula to be determined:

(ml Na ₉ S ₉ O,) (normality Na _P S _P 0,) 0.8

= $ active oxygen

Weight of the monomer sample (g)

It may often be desirable to add one or more co-monomers to the acrylate system, for example, to modify the viscosity, solvent resistance, or other properties of the cured or uncured impregnant. Although an acrylate mixture can often be used successfully, other <** unsaturated comonomers can be used as well. These co-monomers are generally monomers which are capable of relatively rapid polymerization of the vinyl polymerization type, so that they can copolymerize, at least to a limited extent, with the reactive acrylate monomers. For example, alkyd resins such as a

(Dimethyldiphenylmethane) fumarate and diethylene glycol maleate phthalate and other unsaturated monomers such as diallyl phthalate and dimethyl itaconate can be used successfully. Dessl 'chen can prepolymers of the above co-monomers, up to about 3000 molecular weight can be used.

If non-acrylate co-wionomere are used, they should preferably not be used in Remember that about $ 50> of the total weight of the Aoryla "monomeric exceed the system. Other ingredients can just as well be added to the impregnating agent.

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be joined, provided they do not interfere with the desired Sealing function of the composition. It can e.g., colorants, plasticizers and inhibitors in appropriate amounts can be used in these compositions without them affect the usefulness of the composition.

C) The hardener

When the impregnating agent described above is used to seal porous metal objects, it cures under the α, anaerobic conditions of the interior of the object under formation a hard, resistant resin. However, there is sufficient contact with oxygen on the surface of the object, bo that a thin film of the impregnating agent remains in the uncured or more likely partially cured state. • This film is undesirable because the uncured impregnating agent will remove its surroundings through normal wear and tear or can contaminate with various liquids. More important. is that this film tends to be the subsequent paintwork or Interfere with plating operations that often occur on the metal object are made, and is generally removed in the painting or plating operations, the The painting or plating baths used are contaminated.

The hardening agent necessary for the complete hardening of the impregnation «· Aittelfilmes is used on the surface of the porous metal object, must be able to the polymerization reaction to terminate before any uncured impregnant of interest is removed from the article. Without this rapid hardening ability, it is likely that some of the non-hardened or partially hardened impregnation agent removed from the forums near the surface of the metal object. When that happens, the piece is often not usable longer. Although the requirements that are placed on the property the surface of the metal parts, both

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with the intended use - the finished part as well with the type of metal in question and the manufacturing method of porous metal piece may vary as, general Usually it can be said that the hardened waterproofing agent is up to a depth of. under about 0.0254 mm (1/1000 inch) cannot be removed so that the correct plating and Paint properties of the finished product guaranteed are.

It has been found that the most acceptable Härturigsmitteltyp a solute in an organic solvent polymerization accelerator A is acting through free radicals. The organic solvent serves to remove the uncured impregnant on the surface of the porous metal article; Surprisingly, however, as long as the polymerization accelerator is sufficiently active, the uncured or partially hardened impregnating agent is polymerized in the pores before the solvent is able to remove a significant part thereof. A large number of organic solvents can be used in this regard, but the most desirable, because of their excellent cleaning properties, are the halogenated hydrocarbons, especially chlorinated and / or fluorinated hydrocarbons such as methylene chloride, trichlorethylene, λ

Methyl chloroform and trichloromonofluoromethane. Other solvents that can be used are paint solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and ethyl acetate, and also solvents such as xylene, benzene and toluene. If somewhat less desirable, they may nevertheless alcoholic solvents are used, such as methyl alcohol, ethyl alcohol, butyl alcohol and isopropylalkohoie course _r Kings nen also LÖBUngsmittelgemische be used. If water-soluble impregnating agents are used, water or other aqueous solvents can be used, provided that the free radical polymer is also sationabeeohXsuniger

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soluble in aqueous solvent. An excellent water-based hardener is sulphurous acid. If one usually Gaseous or liquid free-radical accelerator is available, the accelerator can be used in pure form Can be used without the accelerator in any state Type of solvent being dissolved. Of course, the ability to change the outer surface of the impregnated piece clean, may be less in these circumstances, but the cleaning power is not absolutely essential for all applications. A typical liquid hardener of this type is tributylamine and a typical gaseous one is sulfur dioxide.

Any free radical polymerization accelerator having the capabilities described above can be used in the process of the present invention can be used. Of the large number of classes of such accelerators available are the listed below are preferred, since all of these classes are able to serve the purposes described here particularly effectively to serve.

1 · Aldehyde-Amin condensation products

Typical examples of these materials are described in U.S. Patent 2,578,690. Aldehyde-amine condensation products are complex mixtures of a large number of compounds. Although it is not known which compounds are the governing components, it is known that significant accelerating ability is achieved over wide ranges of aldehyde to amine ratios in the reaction mixture. Preferably the reaction mixture contains about 1.0 to about 3-5 moles of aldehyde per mole of amine used, and most preferably about 1.5 to about 3.0 moles of aldehyde per mole of amine. It was found that a more effective condensation in acidic reaction media,

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as can be achieved in the presence of carboxylic acids. Bs can condensation reaction temperatures are employed from about 2O ⁰ C to about 175 ⁰ C, the optimum reaction temperatures are for example from about 5O ⁰ C and about 10O ⁰ C.

The nature of the aldehydes present in the condensation products of the The accelerators described herein are not found to be critical to the broad concept of the present invention proven. Albeit with a certain accelerating power through the use of aromatic aldehydes (such as benzaldehyde and naphthaldehyde), the <| aliphatic aldehydes proved to be highly preferred. For general purposes, the applicable aldehydes can be given by the formula R CHO, where R- is a hydrocarbon group means having up to about 12 carbon atoms. Of course you can

a - ■ ■ ""
R ^ contain a substituent or a bond, a hydrocarbon or something else which does not adversely affect the condensation product for the purposes described here.

The nature of the amine is also for the purposes of the present Invention not critical, i.e. aliphatic or aromatic amines can be used. Although the primary Amines for use in making the condensation j Products are preferred that can also contain secondary aliphatic ™ or aromatic amines can be used. For general purposes, the suitable amines can be represented by the formula R ^ R NH, where R is a hydrocarbon radical with "bi« su about 14 · carbon atoms and R is either hydrogen or R- represents. Of course, either R · 'or R can be anything Substituents or a bond, a hydrocarbon ' or contain something else that the condensation product is for does not adversely affect the purpose described here "

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Typical examples of aldehyde-amine condensation products that The following are suitable for the invention described here: formaldehyde-p-benzylanilinj acetaldehyde-benzylaminej Butyraldehyde butylamine; Butyraldehyde aniline; Hydrocinnamaldehyde butylamine; Naphthaldehyde-o-toluidinj Heptaldehyde-N-allylaniline.

2. Sulfur-containing free radical accelerators

Although a large number of sulfur-containing free radical accelerators are known to the person skilled in the art, three classes have become apparent ■ t sulfur-containing free radical accelerator as special Proven useful, they are the following:

a.) Organic thiols, for example compounds of the formula R SH.

The nature of R 'is not critical, but should be such that it meets the solubility criteria described above is equivalent to. For reasons of practical

7 versatility and usefulness, R is preferably a Hydrocarbon radical with up to about 10 carbon atoms.

7th
Of course, R can have any substituents or bonds,

contain a hydrocarbon or something else that affects the performance of the thiol for the purposes described herein not adversely affected. Typical examples of geeig- ™ Nete thiols are dodecyl mercaptan, octyl mercaptan, phenylene dimercaptan, Dithioacetic acid, thioglycolic acid, thioglycerin and thiobenzyl alcohol j

b) organic disulfides, e.g. compounds of the formula

R ⁸ -SSR ^, in which K ⁸ and R ^{9 are} each the same as R, as defined above under a). Typical examples of suitable disulfides are phenyl disulfide, ethyl disulfide, benzthiazyl disulfide, tetramethylthiuram disulfide and dipentamethylene thiuram disulfide; and

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ORIGINAL INSPECTED

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c) the most preferred class of sulphurous Compounds, organic compounds that are either a

So
Q—

η ι

-N-G- or a -N = C group, e included. The NUS arrangement seems to be the critical factor in compounds of this type to be, and the nature of the rest of the molecule seems for the ability of the compound to be used in the context of the present invention is not intended to be determinative. Describes E.g. the appropriate connections through the formulas: '

ZS ·, SQ (k

9 it and, ^

X-W Π V Y W-P-V ■

—-IS — v— XA— Si— u — i

, so either one of the two or both radicals X and Ζ /

K) TO

Be hydrogen or R, where R is an alkyl, cycloalkyl, Aryl, aralkyl or another hydrocarbon radical with represents up to about 10 carbon atoms. Similar can

Y is hydrogen, K ¹⁰ , SX, .NXY or NR ¹⁰ , R ¹⁰ , X and

Y have the meaning defined above. Q can be E ₉ R, ^v SX or some other _{-S_ Qruppe> where all}

Y-G = N-X

Remainders have the meaning defined above *

The hydrocarbon groups described above can have one or more substituents .. or. Bonds »contain hydrocarbon residues or something else? what the sulfur-containing compound for the purposes of the invention described here is not adversely affected For example, the ER ¥ ■ biiidungen often such Substitmentenwie .Hydroxy = ₀ · halo, thio or Aminosubstitueatea contain ^ "and-" bonds such as ether · »» ■ Th-i "ö" _s w ik Iminohtnäwigenp olia © t work the © chweielhait-igasa ¥ © r "blaciiaig®n la the Mes?

= » / £ S approx

0 0 9 8 3 8/18 0 6-

Case 44

Often the substituents X and Y are combined to form a heterocyclic ring which contains the nitrogen and Carbon atoms of

S S

"Or, - groups,

-N-C- -N = C-

S S-Q

Z-N-C and N = C

ft I I

x-y x-y

includes.

(As used herein, the term "heterocyclic ring" includes a polynuclear heterocyclic ring system such as those mentioned below). This heterocyclic ring can assume the following heterocycles: pyrrole, pyrazole, isoxazole, oxazole, isoxazine, oxazine or most preferably thiazole, or the form of a polynuclear heterocyclic ring system such as indole, isobenzazole, isoquinoline, quinoline or, most preferably, benzothiazole accept. Compounds in which the substituents X and Y are combined in a heterocyclic ring structure are preferred embodiments of the present invention. It has been found that these compounds have particularly violent accelerating power when used with the impregnating agent described above.

Typical examples of compounds that fall under the above-mentioned friction of Sxnäetasehieimigr- ¹ and in the invention described here. - :; i; n can »are the following Thioa ^ stamiv. · Jetraaet." ■■■ .-! uram-dieu if id, Thiocarbr ^ iffiet / .yiiUthiGe ''"«, Thioharnatoff,

/ 4 -

0 0 9 8 3 6 / Ι Π Ο Π

Case 44

"N, N '-di cyclohexyl thiourea and 1-allyl-2-thiourea. Typical examples of binding accelerators in which X and Y form a heterocyclic ring, as defined above, are combined are s-triazole-3-thiol, 2-mercaptothiazoline, Mercaptobenzothiazöl, N-Gyclohexylbenzthiazol-2-sulfonamid, N-oxydiethylenebenzothiazole-2-sulfonamide and 5-amino-2-benzimidazole thiol.

3. Compounds that contain an oxidizable transition metal

The transition metals are those metals that have their valence electrons in a "d" lower shell. you belong to groups IHb, IVb, Vb, VIb, VIIb, VIIIb and Ib of the Periodic Table of the Elements .. Experience has shown that the preferred Group of transition metals is the one in which the Elsen, copper, cobalt, Hiekel and manganese are available. The presence of the transition metal in the lower oxidation state appears to be the essential characteristic for the purposes of the present invention and the remainder of the connection does not seem to be Kritlscli au. For example körinen inorganic Compounds containing these transition metals are used like the metal salts, such as the bromides, chlorides, phosphates, sulfates, sulfides and oxides of the Transition metals. However, because of the solubility mentioned earlier, it is preferred to use organic compounds which contain the transition metal.

JSs have been found to be a particularly useful class of jietal-containing organic compounds are the organic, chelated metal complexes of the transition metals described above. The organic, chelated metal complexes are compounds which contain a Metallioii, which in a ring structure is bound by remaining unbound electrons of two or more neighboring atoms. Examples of hostilities that

009836/1 SOG

ORIGINAL

Case 44 '^ V *

Forming comfortably chelated metal complexes are ß-diketones and ethylene and propylene diamines. Typical examples of chelated Metal complexes that can be used in the binding accelerators of the present invention are Eiseh-J pentandione, copper pentandione, cobalt petandione, copper propylene diamine and copper-ethylenediamine.

Another class of useful organic compounds is that of the formula R OM, in which M represents the transition metal

11th
and R is the remainder of the organic acid or the alcohol

R means OH. Typical examples of compounds of this type are iron naphthanate, nickel naphthanate, cobalt naphtha-P nat, manganese naphthanate, copper octoate, iron hexoate, iron propionate and copper hexoate.

In addition, pure organometallic compounds (compounds, which have a direct carbon-metal bond) "can be used. However, compounds of this type are used in lower valence states are not 'easily formed.

Although the theory dictates that the transition metal must be in an oxidizable state, many metal compounds containing metal atoms that appear to be in a fully oxidized state work acceptable in the accelerator accelerators of the present invention. While the inventors are unwilling to be bound by any specific theory, it appears that these results are attributable to the following two possible factors, among others. First, a certain percentage of the metal compound is constantly in one or more oxidation states other than the highest oxidation state. Second, the compositions described herein may contain a sufficiently active reducing agent that some of the metal content of many metal compounds is reduced to a lower level of oxidation. Although it is understood that all such

- 24 -

009836/1806

Case 4-4

Systems lie within the broad scope of the present invention, the invention speaks here of "oxidizable transition metals ¹¹ , since this appears to be the state that exists when the products and the processes described here are used.

The procedure :

The type of apparatus used to carry out the sealing operation of the present invention is not critical. Depending on the size, shape and type of the porous metal object to be sealed, as well as the The number of objects to be sealed per unit of time can be a large number of different technically available devices be used. For example, if very few and very small porous metal objects to be impregnated can be a surface laboratory dish, because in this flat one Shell the appropriate contact with atmospheric oxygen is retained, whereby the required stability of the liquid impregnating agent 'is ensured.

If a small impregnation operation is sufficient, a small tank equipped with vigorous agitation is suitable, since the agitation continuously brings the impregnant into contact with atmospheric oxygen, which in turn ensures the adequate stability of the impregnant. etc. This is particularly true for impregnating lower viscosity such as about 25 centipoise or less. By far the most useful, and desirable system, a preferred embodiment of the present invention, is that the impregnation vessel is provided with one or more ventilation lines to supply the impregnation agent with a continuous flow of oxygen. As described above, this same approach can be used to impart anaerobic properties to certain acrylate monomers. With every type of clay anaerobic system, ventilation provides the necessary ventilation

009856/1806

Gases 44

Stability as fresh, atmospheric oxygen is continuously added to the whole bulk of the impregnant and not just to that near the surface. The aeration also provides agitation which gives the liquid the necessary agitation to stabilize the whole composition and thereby prevent local hardening, such as near the outer walls for the liquid impregnant where the aeration does not necessarily penetrate. The strength of the ventilation can vary over a wide range, depending on the specific impregnating agent chosen and the size and geometry of the device used. Of course, for best results, the air that is bubbled into the liquid impregnant should be adequately distributed throughout the body of the liquid. For example, it was found that for a normal (Dank containing about 37.9 1 to about 18y 1 (10 to bO gallons) of liquid impregnant, an air flow velocity of about 0.0142 τε? / Wlxl to about 0.142 m / min ( 0.5 to!?, 0 cubic feet per.minute,) is more than appropriate to ensure the necessary stability.

The minimum amount of air that must be supplied is that the liquid anaerobic material for a reasonable period of time, such as a week or more, from polymerization withholds so that its use is permitted in sealing operations. Although no exact minimum rate is given Since this number fluctuates from one composition to another, it can be said that a safe lower one The limit for the systems described here would be an air volume per hour that is equal to about 10 # of the volume in the impregnation vessel impregnating agent contained would be. With regard to the upper limit, it is ultimately expediency and economic efficiency the determining factors, since extremely high flow velocities are more inefficient than harmful to Sjetea. Its practical upper limit would be a volume of air

- 26 -

009836 / 1B06

ORIGINAL INSPECTED

Case 44

that is equal to the volume of the impregnating agent in the impregnating tank were.

When using articles of uniform porosity, "and the objects only have to be sealed against a slight pressure, it is possible to close them using a dipping technique impregnate .. When the object is immersed in the anaerobic impregnant, the low viscosity allows and low surface tension of the impregnating agent allows penetration into the porous article to an adequate extent Depth. Acrylate materials are special in this regard effective. It is found that when cured there is an adequate seal against low to moderate pressures.

In order to seal against higher pressures or to achieve maximum reliability and durability, it is usually necessary to evacuate the pores of the porous metal article in order to ensure that they are filled with the impregnating agent. This is generally accomplished by placing the porous articles in a vacuum jar, sealing the jar, and then applying and maintaining a vacuum until the pores of the metal porous article are adequately evacuated. Although any degree of evacuation can be used that corresponds to a suitable seal of the porous object for its intended puncture, it is generally desirable to evacuate the porous metal object to the extent that at least about 50 ° of the accessible cavity of the object with the anaerobic ImpräfiJiiv.i .'- medium is filled. Am'bevorzugtesten be at least about 80 evacuated io the achievable cavity of the porous metal article with vmä dsm "impregnating agent is filled most desirable method for carrying out this evacuation is the. porösen.'Metallstücke in. to immerse the anaerobic impregnation agent ₉ while the objects are in the 'vacuum vessel

. ■ 009836/1806

Case 44

-is-

Find. If a vacuum is applied to the vessel, the gases in the spaces between the porous metal objects are removed. The vacuum is then released while the porous articles are still covered by the anaerobic impregnant are. The increased pressure then pushes the anaerobic sealant into the evacuated spaces and thus completes the impregnation operation. When hardened, the anaerobic sealants form a hard and tough seal.

Other manipulations for using the present invention around the porous metal objects may suggest themselves to those skilled in the art to seal. However, these are considered to belong within the scope of the present invention. It is e.g. possible to place the objects in an empty pressure vessel, evacuate the vessel to remove the gases from the spaces between the pieces of metal and then the sealant to be introduced into the vessel. Having enough sealant has been introduced into the vessel so that the porous metal pieces are covered, the vacuum can then be removed to complete the sealing operation.

The temperature at which the impregnation operation is carried out is determined by the stability of the impregnation agent. Since the stability of the anaerobic impregnant decreases with increasing temperature, it is therefore undesirable as a rule, temperatures maintained above about 48.9 ° C (120 ⁰ P). Although the sealing operation can be completed at any temperature at which the sealant is in the liquid state, it is generally inconvenient and impractical to keep the impregnant at extremely low temperatures. Although the lower limit for the operation is basically just a matter of expediency

- 28 -

009836/1806

Case 44-

is, is the practical limit, taken in conjunction with the functionality of the technical working, at about -1., 1 ⁰ C (3O ⁰ F). It has been found that the most desirable operating range is between about 10 and about 29,4- G O ^{0 0} C (5.0 to 85 ⁰ I ^1). It is most convenient to work at room temperatures. At the end of the impregnation operation, the porous metal objects can be treated immediately with the free-radical polymerization accelerator, preferably they are left:

Gytwa

but elapse for a short time, such as 5 to / 120 minutes. Preferably this time is between about 10 and about 30 minutes. This period is particularly advantageous when the treated parts to be painted or plated, since it has a ^par-: m tielle surface curing of the anaerobic impregnant near the Oberr of the metal piece permitted. Although curing is not complete until the treatment with the free radical polymerization accelerator has taken place, this partial curing increases the resistance to removal during treatment with the curing agent and thus creates a better surface for later plating or painting.

The treatment of the impregnated porous metal articles with the hardening agent can be carried out by any convenient method, such as by spraying the pieces with a solution of a free radical accelerator of the above-mentioned type in a solvent. If a gaseous free radical accelerator is used, the pieces can simply be sprayed with the free radical accelerator in its gaseous state. The most desirable method of treating the porous metal objects with the accelerator is the A-r immerse the objects in a tank containing a solution of the accelerator in a solvent "Small pieces are conveniently placed for such operations in baskets or trays and larger pieces can be used individually be handled. The duration of the treatment only needs to be measured in such a way that an

- 29 -

009836/1806

Case 44

te curing of the sealant takes place close to the surface of the porous metal piece. Even if this time of one Accelerator to another fluctuates, it can usually be said that about 5 seconds to about 10 minutes delimit the normal working area, although in most cases used much longer times without any disadvantages can be. With the overwhelming number of the free-radical polymerization accelerators discussed above acceptable results are obtained within about b seconds to about 2 minutes.

For the purposes of the present invention, the temperature of the treatment with the free radical accelerator is not critical, although the effectiveness of the treatment decreases with decreasing temperature. In general, a treatment above about 4.4 0 (40 F) is adequate and preferably takes such treatment from about 1O ° C and 57.8 instead of ⁰ G (50 to 1Ou ⁰ F). Since one of the most sought-after features of the impregnation process described here is the fact that curing takes place without a special heat treatment, people prefer to work at room temperatures. The choice of the absolute upper limit of the operation is basically only a matter of convenience, but in general it is determined by the nature of the solvent or solvents used. As stated above, however, higher temperatures are not needed or used in the preferred aspects of the present invention.

As mentioned above, the use of a solvent in conjunction with the accelerator for free radical polymerization provides the additional benefit that cleaning takes place without adversely affecting the plating or painting properties of the article after the sealing operation has been completed. It was found, that the use of this solution of the accelerator in a solution

- 30 -

009836/1806

Gases 44

The solvent causes an excellent "cleaning of the surface", which is particularly important in the case of complicated objects that have holes and other internal openings. Hardened sealant in such places often impairs the desired sanction of the object. As noted above, this cleaning is accomplished without significant amounts of the impregnant being removed from the interstices of the article (e.g., greater than 0.0254 mm (1/1000 of an inch) in the porous article). After completing the operations described above, the solvent is allowed to evaporate from the surface of the cast iron. In general, the sealed metal articles have been found to develop the ability to withstand substantial pressure within minutes of treatment with the curing agent ß>, e.g., at least about 2.7 kg / cm (25 psig ^ Z · JSs advisable. wait with testing or using the pieces at elevated Print </£.B than about 8.03 kg / cm (100 psig) 7 ² ^ = to about 30 minutes from the end of the impregnation of, and at least about 15 minutes have passed from the completion of the treatment with the free radical polymerization accelerator. This period of time allows the anaerobic curing to proceed to near completion, at which point the sealed porous metal articles are ready for the subsequent treatment, such as Plating or painting.

The following examples are intended to illustrate the use of the components and the process steps of the present invention Impregnation and sealing of various porous objects show, but are not intended to be a limitation. Unless otherwise stated, all are given below Ratios and percentages based on weight.

31 -

0098 36/180 6

Case 44. 32. ·

example 1

A mixture of acrylate monomers was prepared by 2/3 (based on weight) triethylene glycol dimethacrylate mixed with 1/3 (based on weight) lauryl methacrylate. to to this mixture was added approximately 1% by weight of cumene hydroperoxide, approximately 0.3 wt .- $ benzoic acid sulfimide and about 3 ppm (based on by weight) copper (as copper octanoate). Approximately 75.7 liters (20 gallons) of this finished mixture was placed in a vacuum tank ^ approximately 0.283 m (10 cu.ft.) _ 7 transferred, of flexible connectors to a vacuum pump. One "6.35 mm (1/4 inch) polyethylene vent line was connected to an air compressor at the bottom of the tank. Immediately after the transfer of the The impregnation agent in the tank was started with aeration, the air with a pressure of 1.42 kg / cm; Section. (6 psig) became.

In order to test the stability of the impregnating agent, one sat ventilation continued for about 2 days, during which time the anaerobic mixture remained fluid. No significant was found Change in viscosity solid, indicating the absence of any significant amount of polymerization.

The mixture was then used to impregnate die-cast aluminum pieces, rectangular, solid, gauge housings approximately 7 »62 by 5.08 by 4.40 cm (3x2x1 3/4 inch) J. The parts contained 10 blind tapped holes. Before the impregnation, the aluminum parts were washed with water for cleaning and degreased in the steam phase. The cleaned parts were placed in a stainless steel rack and hung in the impregnation tank so that the parts were completely immersed in the impregnation agent. The tank was capped, sealed and the air evacuated using a vacuum pump.

- 32 -

009836/1 806

Case 44

An absolute pressure of approximately 2.54 cm Ω inches of mercury was reached in less than 2 minutes, and this vacuum was maintained for approximately 10 minutes. The vacuum pump was then switched off and the pressure gradually increased with the aid of a relief valve. After the pressure had reached atmospheric pressure, the tank was opened and the insert with the impregnated parts was removed from the liquid and approx
Allowed to drain for 5 minutes. Then the insert was removed and immersed in a trichlorethylene solution, the TO $
Isopropanol, 2 $> mercaptobenzothiazole and 2 # Dimethyl contained, the latter two are the accelerators for free-radical polymerization M. After 10 seconds, the insert was removed and the parts were allowed to stand at room temperature for about 6 hours to allow the sealant to fully cure.

The sealed, porous metal pieces were found to have a smooth, clear surface with no visible signs of sealant anywhere on the surface, including the inner surface of the blind holes. However, it was found that the sealant was essentially used for
outer surface of the castings was hardened. The process was used to impregnate 300 die-cast aluminum pieces.

2 'd

ren, whereupon all at a pressure of 15.1 kg / cm, abs. "

(200 psig) were tested. It was found that in none of the 300 pieces of leakage occurred.

Example 2

The apparatus, anaerobic impregnant and free radical polymerization accelerator of Example 1 above were used to make cams of sintered iron powder
impregnate, each weighing approximately 28.35 g (.1 ounce). Of the
The only difference between the procedure and that described in Example 1 was that no vacuum

009836/1806

Case 44

treatment was applied; instead, the inserts containing the sintered iron parts were immersed in a sealant and in that position for approximately approximately 20 minutes left. Then the parts were allowed to drain off, they were washed with the rinsing solution, which contains the free-radical polymerization accelerator and allowed to cure for 6 hours at room temperature.

It was found that a significant percentage of the gases contained in the sintered metal parts had been removed by the low viscosity sealant which penetrated the parts. (This penetration was shown during the impregnation operation by tiny gas bubbles rising from the surface of the metal parts. Immediately after the inserts with the porous metal parts were immersed in the sealant, a large number of these bubbles could be detected, the number of which gradually decreased and the number before completion completely disappeared after the 10 minute impregnation). After allowing the impregnant in the parts to cure for about b hours, the parts were found to be sealed to low pressures, with all parts being subjected to a pressure of at least about 2.41 kg / cm; Section. (20 psig) withstood.

Example 3

About 150 ml of triethylene glycol dimethaerylate containing 1% by weight of benzoyl peroxide were placed in a 250 ml vacuum flask. Air was gradually bubbled through the mixture from a laboratory compressed air line. The aerated mixture was found to be stable at room temperature, as evidenced by the fact that it remained fluid and there was no noticeable increase in viscosity over a period of about 48 hours. Thereafter, the aerated mix to impregnate a number of cams of sintered iron powder, each weighing about 28.35 g (1 ounoe) was used _f. About 10 of these porous

- 34 -

009836/1806

Case 44-. '. "35 * ·

Metal objects were placed in the vacuum basket, completely immersed in the anaerobic impregnant. Then became the flask evacuated to an absolute pressure of about 1.27 cm (0.5 inches) of mercury, the pressure becoming approximately Maintain TO for minutes. Then the vacuum pump turned off and you let the vacuum flask gradually over a Return to atmospheric pressure for approximately 1 minute. The impregnated parts were then removed and allowed to drain for about 5 minutes, whereupon they were immersed in the free radical accelerator solution described in Example 1 above. After 10 seconds the parts were taken out and left to stand overnight, so that a complete hardening could take place. The parts

were then at 15.1 kg / cm; Section. (200 psig) tested and all found to be actually sealed.

The materials and procedures described above in this example were then used to make sintered brass test pieces (disks approximately 2.54 cm (1 inch) in diameter and 1.587 mm (1/1 inch) thick) weighing approximately 5 x 67 δ (0 »2 ounce) to impregnate. The parts were successfully impregnated and found to be effectively sealed against a pressure of at least 2.41 kg / cm; Section. (20 psig) tested after getting. let it harden overnight. - ■ · - '

Example 4

The anaerobic sealant described in Example 5 above was used in combination with a cellulose acetate butyrate resin to make a higher viscosity impregnant. The resin had a viscosity in solution (ASTM # D 1243-54T) of about 25 seconds. The weight percentage of acetate was 21 # "the weight percentage of butyrate was 28 $ and the weight percentage of hydroxyl was 2.5 #", Das

'009836 / V80B

Case 44

More viscous impregnation agent was made by using ucluose acetate butyrate resin added in three increments to triethylene glycol dimethacrylate. After each partial addition was Mix the mixture until all of the resin is complete was resolved. After about 14.17 g (0.5 ounce) of the resin was dissolved in about 726 g (1.6 pounds) of dimethacrylate, the remainder was added of the ingredients for the anaerobic sealant. The viscosity of the finished mixture was 25 centipoise. The mixture was immediately transferred to a 1 l beaker and ventilated with compressed air from the laboratory. The ventilated sealant was found to be a stable composition at room temperature, as evidenced that it was over a period of Remained liquid for 48 hours without any noticeable increase in viscosity.

The anaerobic sealant was then used to seal a stainless steel disk (15mm diameter, 3mm thick), with a known porosity of about 1UO / U is used. the Disk was immersed in the sealant for 15 minutes, then removed and immediately in the for about 10 seconds Solution of the free radical polymerization accelerator described above in Example 1 rinsed. After you get them around Left to cure for 30 minutes, the disc tested below 2.41 kg / cm; Section. (20 psig) as free of leaks.

Example 5

A sintered iron dial / approximately 3 inches diameter, 1 inch thick_7 was impregnated in preparation for plating. The impregnating agent was composed as follows: polyethylene glycol dimethacrylate (throughput ^1-average molecular weight = 330) 97.3 wt .- #; Cumene hydro peroxide, 2 wt .- ^; Dimethylparatoluidine, 0.4% by weight and benzoic acid sulfimide, 0.3% by weight. This anaerobic impregnation agent was found to be stable under aeration, as in the previous ones

- 36 -

009836/1806

ORIGINAL INSPECTED

Case '44

Examples described. The wheel was made using the general Impregnated method described in Example 1 above using a 10 minute vacuum period and then for 10 seconds in the example 1 above described solution of the free radical polymerization accelerator immersed. Then you left the bike for 72 hours stand at room temperature.

A second wheel was slightly impregnated using one more viscous impregnation agent, prepared by mixing 75 wt .- $ of the sealant described in Example 1 with 25 wt .- $ of a more viscous acrylate resin, the 0.1 wt .- # cumene hydroperoxide contained. The more viscous resin was the reaction product of 2 moles of hydroxyethyl methacrylate with

1 mol of the reaction product of dimethyldiphenylmethane with

2 moles of toluene diisocyanate. The final viscosity of this sealant was approximately 20 centipoise at room temperature. The method used to impregnate the second dial with this more viscous impregnant was the same as that used for the first dial in the present example. Both wheels were subjected to an electrolytic zinc plating process. It was found that the plated wheels had excellent surface properties, substantially free of surface scars and other defects which usually occur freely in the zinc plating of parts, which were impregnated by known methods.

Example 6

A mixture of polymerizable acrylate monomers was produced by mixing triethylene glycol dimethacrylate and lauryl methaorylate in a weight ratio of 2: 1. It presented an anaerobic impregnant ago by echung to this micro 1 i> Oumolhydroperoxyd and about 1.2% tributylamine back

■: _. , ^-.-,::, / ■: ■ "■ ~ 37 ·, · - · .- ■ ■ V ■■ - ■; ■■ 'V; P9836 / 1806th...

,:, ■ / ■■■■ '■' ■ ^; .: .- ■■ ..; ; j; . : _; . . - ^s ß ORIGINAL: INSPECTED

Case 44 "^ *

added. There was about 500 cnr of this anaerobic impregnation agent one in a 1 1 vacuum vessel and ventilated with laboratory compressed air. 4 ppm copper (as copper octanoate) was then added to the aerated mixture.

The anaerobic mixture was used to impregnate sintered iron cams, each weighing about 28.35 g (1 ounce), using the method generally outlined in Example 1 above. The solution of the accelerator for free radical polymerization was the same as that described in Example 1. After allowing the parts to cure overnight, they were found to be usable for sealing, dividing
(40 psig).

gel, tested at a pressure of about 3 _f 81 kg / cm; Section.

Example 7

The impregnation procedure of Example 1 was repeated using 4 ppm cobalt (as cobalt pentanedione) in place of the copper. Essentially the same results were obtained in that the impregnated parts were effective against a pressure of a few
were sealed.

Pressure of at least about 8.03 kg / cm; Section. (100 psig)

W. Example 8

The impregnation agent and the method of impregnation were used of Example 1 to seal sintered iron cams of 1 ounce, but using the following solution used as curing agents, the first two components are accelerators for free radical polymerization.

009836/1806

ORjQJNAL INSPECTED

Case 44

Component approx.% By weight

1 ', 2-diamino propane $ 0.5

Copper-2-ethylhexoate 1.5%

1,2 propylene glycol 3 ⁰ A

Butanol 30 %

Trichlorethylene ' $ 65

Essentially the same results were obtained, in that the porous metal articles are effective against a pressure of at least about 8.03 kg / cm j abs. (100 psig) were sealed.

In the example above the solution is the accelerator for free radicals Polymerization in a solvent completely or partially replaced by a solution in a solvent, which contains a comparable amount of one of the materials listed below, or a mixture thereof, im achieved essentially the same results in so far as the impregnated Objects are effectively sealed, essentially on the outer surface, so that surfaces are created that can be successfully plated or painted- ™ nent

1. The reaction product of 2 moles of butyraldehyde with 1 mole Butylamine »

2. The reaction product of 3 moles of acetaldehyde with 1 mole Benzylamine.

3. Octyl mercaptan

4. EthyXdisulfide ''

- 39 -

009836/1806

■ "■ ', .. _{: s} -, ORIGINAL, INSPECTED

te

Gases 44

5. 1-Allyl-2-thiourea

6. Copper dimethyldithiocarbamate

7. Cobalt naphthanate

8. Copper pentandione

9. Dimethyl-p-toluidine

Example 9

An anaerobic waterproofing agent was prepared which was composed of the following approximate compositions, expressed in percent by weight, duration:

Hydroxyethyl methacrylate 97 »7 %

Cumene hydroperoxide 2.0 %

Benzoic acid sulfimide $ 0.3>

■ 100.0 $>

To this mixture was added 3 ppm by weight copper (as copper octanoate), two 250 ml beakers were filled approximately halfway with this impregnant, and each was ventilated with laboratory air for approximately 1/2 hour. Thereafter, a set of the cups in a desiccator and placed three sintered iron test pieces of 2.54 cm in diameter (1 inch) and 3 '175 mm thickness ψ (one-eighth inch) in the impregnating agent. A vacuum was applied to the desiccator for approximately 10 minutes / absolute pressure less than 2.54 cm (1 inch) of mercury_7. The vacuum was released, the test pieces removed, and the impregnant vented again. At this point, the beaker was stopped from venting with the impregnating agent which had not been used in the impregnating operation. The test pieces were placed in the free radical accelerator solution described in Example 1 for approximately 15 seconds . After about θ hours, the two cups were impregnated

- 40 -

009836/1806

BATH

Case 44

kidney agent and the test pieces examined. The impregnation agent used in the impregnation operation and subsequently had been aerated, showed no change in viscosity, whereas the impregnating agent, with which the ventilation had been interrupted, had started to gel what was upon it indicated that substantial polymerization was beginning to occur. The test pieces were found to be effective as they sealed successfully a pressure test at 5 »81 kg / cm j abs. (4U psig) resisted. .

Example 10

The procedure of Example 9 was repeated exactly with the Exception that butylene glycol dimethacrylate was used instead of hydroxyethyl methacrylate. Results were obtained practically similar to those described in Example 9 above.

ir '

Example 11 ■ ·

In order to demonstrate the impregnation of parts other than metal parts, the materials and process steps described in Example 1 above were used for impregnating wooden (birch) rifle butts. 94 g of a walnut-colored dye were added to 7 liters of impregnating agent. '·

After the treatment, after impregnation with the solution of the free radical accelerator in a solvent, the rifle butts were placed in a closed chamber which was provided with a valve connection to a cylinder with compressed sulfur dioxide gas. The chamber was closed, a relief valve was opened and the existing atmosphere was flushed out with sulfur dioxide. The rifle butts were left in a sulfur dioxide atmosphere for about 30 minutes. The examination revealed that the rifle butts had assumed a deep walnut color and a hard, permanent "water and solvent-resistant" surface finish. Ai

"^; 009836/1806

Claims (12)

■ η- Jan 13, 1970 LOCTITE CORPORATION Case 44 Claims A method for sealing porous, rigid objects, characterized in that one impregnates the interstices of the overall W gens tandes with a polymerizable, anaerobic sealing agent, and treating the impregnated article with a curing agent for the anaerobic sealant. 2. The method of claim 1, characterized in that the polymerizable _t, anaerobic sealing agent is a free-radically polymerizable monomer and a polymerization initiator Hedox therefor. 3. A method for sealing porous objects, characterized in that that a) the interstices of the object with a mixture of at least one polymerizable acrylate ester and impregnated with a redox polymerization initiator for this purpose will; and b) the impregnated articles with a polymerisation accelerator to be treated for the mixture. 4 · Method of sealing porous. Metal objects, characterized in that - 42 - 009836/1806 • Η- Case 44. a) the object is exposed to a vacuum; to) after the interstices of the object have been evacuated, the object with a anaerobic sealant is covered, which is a polymerizable acrylate ester and a Contains redox polymerization initiator therefor; c) the vacuum is removed .will * around the sealant . to drift into the evacuated spaces; and _3 d) the surfaces of the impregnated objects with a polymerization accelerator for the sealant. , 5. Process for sealing porous metal objects, characterized in that. a) an anaerobic sealant by mixing of a polymerizable acrylate ester with a Kedox polymerization initiator is produced for this purpose; to) the sealing agent placed in a vacuum vessel and the sealant is sufficiently ventilated so that the polymerization of the Sealant is prevented; c) the porous metal objects to be treated in the anaerobic sealants are submerged; d) a vacuum of less than about 12.7 cm (5 inches) absolute mercury pressure applied to the vessel will; - 45 - 009836/1806 Case 44 e) after the interstices of the object have been evacuated, the vacuum is released to release the sealant to drift into the gaps; f) the impregnated object is removed from the sealing agent, and the object with an accelerator for free radical polymerization is treated. 6 · The method according to claim 3 »characterized in that the Redox polymerization initiator a peroxy redox polymerization initiator and at least part of the polymerizable acrylate ester has the chemical formula: H ₂ C = CCO • p IT - (CH ₉ ), 0 - C-C = CH, where R is hydrogen, lower alkyl of 1 to about 4 carbon atoms or 0
-OH ₂ -UCC = CH ₂ means, 2
R is hydrogen, halogen, or lower alkyl of 1 to about 4 carbon atoms; ¹ JC R ^ hydrogen ι hydroxyl or ·. . 009836/1 806 Case 44 -0-S-G = CH 2
2 means; m is an integer of at least 1; η is an integer of at least 1; and ρ means zero or 1. 7. The method according to claim 6, characterized in that the Redox polymerization initiator the combination of an organic hydroperoxide and an accelerator for the Hydroperoxide decomposition is. 8. · The method according to claim 3 »characterized in that the Polymerization accelerator for the anaerobic sealant is dissolved in an organic solvent and has enough activity to make the sealant to harden vigorously to the outer surface of the object. 9. The method according to claim 8, characterized in that the polymerization accelerator is selected from the following classes becomes: aldehyde-amine condensation products; sulphurous, free radical accelerator; or organic compounds containing an oxidizable transition metal. 10. The method according to claim 5, characterized in that the. Redox polymerization initiator is a peroxy redox polymerization initiator and at least part of the polymerizable acrylate ester has the chemical formula " ⁴⁵ ~ 00 98 36/1806 Case 44 OH ₀ C = UCO R I C I, R- R ¹ - CO R ¹ - CC = (JH ₀ owns what R is hydrogen, lower alkyl having 1 to about 4 carbon atoms, hydroxyalkyl having 1 to about 4 carbon atoms or 0 -CHo-OCC = CH ₀ i: R ' means, R is hydrogen, halogen or lower alkyl of 1 to about Means 4 carbon atoms; 3
R is hydrogen, hydroxyl or O-O-C-C = CH m is an integer of at least 1; η is an integer of at least 1} and ρ means zero or 1. 11. The method according to claim 10, characterized in that the redox foiymerisationsinitiator is the combination of an organic hydroperoxide and an accelerator for the hydroperoxide decomposition. - 46 - 009836/1 806 Case 44 12. The method of claim 5 _t characterized in that the vacuum is less than about 2.54 cm (1 inch) mercury absolute pressure. 13 · The method according to claim 5, characterized in that the accelerator for free-radical polymerization for the anaerobic sealant is dissolved in an organic solvent and has sufficient activity, to vigorously harden the sealant to the outer surface of the item. 14 · The method according to claim 13, characterized in that the accelerator for free-radical polymerization the following classes are selected: aldehyde-amine condensation products; sulfur-containing free radical accelerators; or organic compounds that are oxidizable Contain transition metal. 15 · The method according to claim 5 »characterized in that at least part of the acrylate ester is a polyethylene glycol dimethacrylate is the redox polymerization initiator Combination of cumene hydroperoxide and an oxidizable transition metal, and the accelerator for free radicals Polymerization is mercaptobenzothiazole. - 47 - 009836/1306