AU711064B2 - Improved floor coating removers - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990

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COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

9* *5 5

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59

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Name of Applicant: Actual InventorS: Address of Service: Invention Title: WHITELEY INDUSTRIES PTY. LTD. A.C.N. 000 906 678 Bruce Alan WHITELEY and Reginald Keith WHITELEY SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 "IMPROVED FLOOR COATING REMOVERS" Details of Associated Provisional Application No. PN7751 dated 29th January, 1996 The following statement is a full description of this invention, including the best method of performing it known to us:- FIELD OF INVENTION The present invention relates to chemical compositions suitable for the removal of aged or dry resinous coatings, in particular to removal of damaged polymeric floor coatings.

BACKGROUND TO THE INVENTION It is necessary to regularly remove aged polymeric floor coatings and sealers from a variety of commercial and domestic floorings. This usually becomes necessary because of either uneven wear, hence uneven appearance, progressive discolouration of coatings due to soiling or oxidation, and/or strongly adherent soil films on coatings not readily removed by regular maintenance chemicals. Other factors such as localised damage due to misadventure, accidental spillage of chemicals that damage resinous floor coatings and S •physical damage as, for example, dragging of loaded pallets over polished floors, may each necessitate removal of organic coatings.

S•.i Over the past three decades many different chemical approaches have been employed *15 to remove aged or damaged floor coatings, in particular synthetic floor coatings variously described as sealers, sealer-finishes and polishes. These coating are generally emulsion polymers based on mixtures of styrene, acrylic, epoxide, urethane and vinyl resins together with a coalescent such as glycol ethers, plasticisers such as butyl phthalate and tributoxy ethylphosphate, together with polyethylene emulsions to give buffability and so-called brightening resins such as high acid number styrene maleic anhydride resins incorporated as their ammonium salts.

S' A very wide variety of such resins are found in commercial floor coatings each with its own balance of chemical and physical properties. As they age different resin combinations develop differing chemical reactivities to normal commercial floor strippers.

This occurs particularly where either aqueous urethane, epoxy or vinyl resins are mixed with acrylic resins then subjected to regular buffing with high speed (2000 3500 rpm) polishing machines which harden coatings due to heat developed on floors during buffing.

These latter resin blends are now quite commonly used to coat, protect and maximise appearance of large open floor areas such as modem shopping malls, arcades, shopping complexes, retail stores and public buildings.

There are many common combinations of chemicals that are used for stripping (removing) aged floor polishes. These mixtures normally comprise two or more of the following chemicals.

1 Alkaline substances such as sodium hydroxide, potassium hydroxide, sodium and potassium metasilicate, sodium carbonate and other soluble monovalent metal salts.

2. Ammonium hydroxide and/or monoethanolamine, isopropanolamine and other odourless organic amines.

3 Water softening agents and/or chelating agents such as poly phosphates and tetrasodium ethylenediamine tetraacetate.

4. Buffering agents to regulate the pH of the product at use concentration such as salts of phosphoric and boric acids.

5. Water soluble or partly soluble solvents in particular those derived from either o" ethylene glycol or propylene glycol eg. ethyleneglycol monobutyl ether and dipropylene glycol monomethyl ether.

15 6. Surfactants such as common soaps, anionic, nonionic, cationic and amphoteric surfactants. Specialty surfactants such as fluorochemical surfactants may also be employed.

7. Dyes, perfumes and small quantities of organic solvents insoluble in water, eg.

S..terpene solvents solubilised by surfactants and glycol solvents.

S 20 Many variations of these constituents are found in products on the commercial market world wide.

Central to the inability or unsuitability of conventional floor strippers manufactured according to the preceding principles for removal of aged polymeric floor finishes is the limitations imposed by the flooring factors. In particular the reactivity of the flooring materials carrying the aged floor finish. Sensitivity to alkaline substances and many common solvents is a major problem to vinyl, terrazzo, marble, wood, some ceramics and most polymeric building surfaces.

Likewise sensitivity to solvents is also a major problem when aged coatings are not readily released or destroyed after application of a conventional floor stripper. Repeated use of stronger solutions of slow acting stripper solutions, a common approach to such a problem, can lead to irreversible damage of flooring surfaces.

The requirement to store and use strong corrosive chemicals on site in modern buildings is a matter of increasing legislative concern around the world. Problems of transport, storage, dispensing, use by humans, training requirements, supervision, workers insurance, collection and disposing of spent solutions after stripping are to be avoided wherever possible.

Thus, there is a need for compositions for removal of dry resinous coverings on floors and other surfaces, which do not suffer from the disadvantages of the prior art discussed above. The products described in this specification permit these problems to be avoided in a simple, economic and safe manner.

SUMMARY OF THE INVENTION According to a first aspect the present invention consists in a composition suitable for removal of dry resinous coatings, comprising: one or more acrylic monomers, one or more surfactants capable of enhancing the penetration of the acrylic 15 monomer into dry resinous coating, and a solvent carrier system.

Preferably the composition may also contain a mildly alkaline solvent and/or a low molecular weight aliphatic or aromatic alcohol containing up to 7 carbon atoms and their esters. The mildly alkaline solvent is preferably an alkanolamine selected from the group consisting ofmonoethanolamine, diethanolamine and isopropanolamine.

According to a second aspect the present invention consists in a method of removing dry resinous coatings from surfaces comprising the step of applying to said coatings a 0 composition according to the first aspect.

The compositions of the present invention may be applied by spray, mop or other similar means or by mechanical means such as a machine scrubber. Any surface which has been covered with a resinous coating may be treated with the compositions of the present invention. Most commonly such surfaces are floors.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The quick removal of aged polymeric finishes from floors is made possible when the stripping solution readily reacts with and breaks up and disperses the bonding forces within aged films.

This most often is cross hydrogen bonding between otherwise semi-discrete resin particles deposited on flooring by newly applied floor finish while it dries and coalesces during the process of film formation. Heat and physical energy subsequently applied to floor coating by daily buffing with high speed heavy polishing machinery (as used to quickly restore uniform high gloss levels) has the ability to further enhance bonding (forging enhanced cross linking) between resin particles making them less penetrable and less dispersible. These latter forces must be overcome to allow the aged film to be destroyed either by dispersing, reacting, partly solubilising and/or lifting from the underlying flooring surface, the latter being the commonly recognised mechanisms by which floor strippers function.

The compositions we have employed to facilitate and greatly accelerate these latter processes make use of aqueous solutions or emulsions of one or more of the common monomers employed in the formation of the acrylic resins in the modem aqueous floor I emulsions. Acrylic resins, often cross linked by zinc, are used to produce the major 15 polymeric ingredient in the manufacture, the current polymeric floor finishes whether acrylic, styrenated acrylic, urethane modified acrylic or styrenated acrylic or epoxy modified acrylic or styrenated acrylic types all of which are in current use.

Original monomers have a natural structural and chemical affinity for the resinous particles which they form and are a part of, particularly acrylic monomers. As acrylic or styrenated acrylic polymers are present in large proportion and form the bulk of most past and current floor sealers and polishes, the ability of monomers to rapidly penetrate such S"resinous particles and cause them to soften and swell allows the other ingredients normally used in floor strippers to more effectively and rapidly perform their individual traditional function as previously described.

The monomer may be either soluble, partly soluble or insoluble in water.

Importantly they must not be possessed of strong or irritant odour. For preference a mixture of monomers will be used, one of which may be insoluble in water, and thus quite hydrophobic in character. The penetration of the hydrophobic monomer can be assisted by the presence in solution of a partly or fully soluble monomer as well as the surfactant system which is employed both to assist in solubilising or emulsifying the insoluble monomer and facilitating penetration of otherwise unreactive resinous particles in aged floor finishes.

-6- The monomers we have found advantageous and which fit other criteria of odour and toxicity, are hydroxyethyl methacrylate, isobutyl acrylate, 2-ethylhexyl acrylate and lauryl acrylate. Other acrylic monomers can undoubtedly perform the same function as may other monomers employed in the manufacture of urethane and epoxy aqueous resins.

The penetration of the chosen monomers can be further enhanced or "activated". By this is inferred that the monomers are conveyed onto the resin surface via the micelles of a surfactant. Preferably the surfactant is chosen for its ability to interface efficiently with the surface of the aged finishes. We have been able to demonstrate that surfactants are able to perform this function in commercial situations, to the point where they show synergism with the monomers. Fluorocarbon surfactants akin to those employed in polish manufacture are a particular example although other surfactants may demonstrate even greater affinity for activating monomer penetration of aged resinous particles.

The surfactants we have found particularly advantageous in our following formulations, but not limited to, are as follows.

15 Fatty acids either saturated or unsaturated containing from 14 to 20 carbon atoms reacted either with a monovalent metal, amine or ethanolamine, or with alcohol containing 1 to 8 carbon atoms to form the corresponding ester.

Anionic or nonionic commercial fluorocarbon surfactants.

Nonionic surfactants based on either alkyl or alkyl aryl polyethoxylates containing from 4 to 18 ethylene or propylene oxide groups or their sulphated or phosphated derivatives.

Common commercial anionic surfactants can also be employed but in our experience are less effective than those previously listed unless mixed with more effective surfactants such as those mentioned above.

An aqueous soluble or self-emulsifying solvent carrier system is employed as the vehicle for the monomers and surfactants in each formulation. Preference is given to the use of a safe, odourless alkyl glycol or polyglycol, glycol, glycol ether or ester and/or a pyrollidone as the principal solvent vehicle. These solvents may also contribute to stripping action, in the same manner as occurs where glycols are employed in conventional floor stripping formulations. Together they will mostly constitute the majority of each formulation other than water.

-7- The presence of a nominal quantity of a mildly alkaline solvent, such as monoethanolamine, diethanolamine and, in particular isopropanolamine, will assist in dispersing resinous particles by reacting with carboxyl groups freed from acrylic resins by the action of the monomer and surfactant. This particular action may be obstructed by any hardness in water used to dilute the stripping concentrate. Hardness is first therefore eliminated by use of tetrasodium ethylenediamine tetraacetate or like chelating agents in small quantity; otherwise calcium and/or magnesium salts may preferentially react with newly released carboxyl groups to the disadvantage of the stripping process.

The presence of a nominal quantity of a pyrollidone solvents such as n-pyrollidone, n-methyl pyrollidone and lauryl pyrollidone assists in wetting, swelling and dispersing polymers of most types, in particular urethane and epoxy resinous particles present in most of the less reactive, harder varieties of high speed floor sealers and polishers.

A number of similar solvents will be recognised by those experienced in the art .I :which can be successfully substituted in the following formulations once the initial 15 softening and partial dispersion of aged resinous film by the surfactant-monomer combination has occurred.

In similar vein, the presence of low molecular weight aliphatic and aromatic alcohols and their esters may also contribute to the penetration, swelling and/or solubilising of some components of aged floor finishes such as brightening resins and residual plasticisers in addition to small quantities of other more esoteric resins occasionally found present in aged films. They may also be required to provide either solubility or clarity to concentrated stripping solutions or assisting stabilising emulsion forms of the product herein envisaged.

Such alcohols will contain no more than eight carbon atoms.

The remaining part of the formulations are either water, trace quantities of dyes, which may include a pH indicator dye to demonstrate product strength in aqueous solution, perfumes and odour masking agents to assure minimal detectable odour from each formulation where advantageous.

The present invention will now be described in more detail by way of non-limiting examples of different formulations.

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EXAMPLES

Examples of compositions of the present invention, manufactured from the aforementioned ingredients, are set out in Table 1 below.

Table 1 Example floor stripper formulations Formulation (as percent w/w) 00.0* 0*0* Ingredient A B C D E F HEMA 1.0 0.5 1.55 IRMA 0.5 2EHA 1.9 1.0 1.5 1.0 1.4 LA 0.1 0.1 MEA 8.5 12.0 15.9 ISPA 10.0 7.5 10.5 BZA IPA 5.0 13.8 nP 12.5 15.0 17.5 nMP 14.0 12.0 32.3 LMP 0.2 0.3 DPM 20.0 17.0 22.5 DEGEE 12.5 14.5 21.0 FC99 0.03 FC129 0.025 12A8 0.15 0.1 0.15 0.15 0.2 0.0 PLa 0.25 MeOl SLS 0.1 0.15 EDTA 0.4 0.4 0.4 0.4 0.4 0.4 WATER Balance to 100 percent (weight/weight) -9- Legend to Table 1

HEMA

IBMA

2EHA

LA

MEA

ISPA

BZA

IPA

nP nMP

LMP

DPM

DEGEE

FC99 FC129 12A8 PLa MeOl

SLS

EDTA

Hydroxyethyl methacrylate Isobutyl methacrylate 2-ethylhexyl acrylate Lauryl acrylate Monoethanolamine Isopropanolamine Benzyl alcohol Isopropyl alcohol n-pyrollidone n-methylpyrollidone Lauryl pyrollidone Dipropyleneglycol methylether Diethyleneglycol diethylether Fluorosurfactant 3M Co Fluorosurfactant 3M Co ICI Chemicals nonionic surfactant, Teric 12A8 ICI Chemicals sulphated nonionic surfactant, Alkadet Potassium laurate Methyl oleate Sodium lauryl sulphate Tetrasodium ethylenediamine tetraacetate

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S. The various formulations are made by first mixing in the above order, the organic ingredients then diluting the resultant mixture with water while agitating with a mechanical 25 stirrer at room temperature. The use of demineralised water is strongly preferred. The ultimate pH of each formulation will be determined by the type and quantity of alkanolamine employed in a particular formulation.

It will be recognised by those skilled in the art that many further variations other than the examples disclosed can be determined; likewise that variations in molecular structure and purity or chemical uniformity of individual ingredients may contribute to the manufacture of alternative formulations with similar effectiveness. Such variations are foreshadowed in the preceding disclosures and deemed to be part of this specification.

Claims (23)

1. A composition suitable for removal of dry resinous coatings, comprising: one or more acrylic monomers, one or more surfactants capable of enhancing the penetration of the acrylic monomer into dry resinous coating, and a solvent carrier system.

2. A composition according to claim 1, wherein the one or more acrylic monomer is selected from the group consisting of hydroxyethyl methacrylate, isobutyl acrylate, 2- ethylhexyl acrylate and lauryl acrylate.

3. A composition according to claim 1 or claim 2, wherein the acrylic monomer is present in an amount from 0.1 to 10.0 percent by weight of the composition.

4. A composition according to any one of the preceding claims, wherein the one or '.'more surfactants are selected from the group consisting of anionic or nonionic surfactants and saturated or unsaturated fatty acids containing from 14 to 20 carbon atoms reacted 15 either with a monovalent metal, an amine or an ethanolamine, or with an alcohol containing 1 to 8 carbon atoms to form the corresponding ester.

5. A composition according to claim 4, wherein the nonionic surfactant is either an alkyl or an alkyl aryl polyethoxylate containing from 4 to 18 ethylene or propylene oxide groups or their sulphated or phosphated derivatives.

6. A composition according to any one of claims 1 to 5, wherein the surfactant is present in a total amount of from 0.01 to 5.0 percent weight of the composition. a.

7. A composition according to any one of claims 1 to 6, wherein the carrier solvent system comprises one or more of a water, soluble glycol, a glycol ether or ester, or a pyrollidone solvent.

8. A composition according to any one of claims 1 to 7, comprising a pyrollidone solvent.

9. A composition according to claim 7 or claim 8, wherein the pyrollidone solvent is selected from the group consisting of n-pyrollidone, n-methyl pyrollidone and lauryl pyrollidone.

10. A composition according to claim 8 or claim 9, wherein a pyrollidone solvent is present in the amount of from 2.5 to 40.0 percent by weight of the composition. -11-

11. A composition according to any one of claims 1 to 10, further comprising one or more of a mildly alkaline solvent, or a low molecular weight aliphatic or aromatic alcohol containing up to 8 carbon atoms and their esters.

12. A composition according to claim 11, wherein the mildly alkaline solvent is an alkanolamine preferably selected from the group consisting of monoethanolamine, diethanolamine and isopropanolamine.

13. A composition according to claim 11 or claim 12, wherein the mildly alkaline solvent is present in a total amount of from 1.0 to 25 percent by weight of the composition.

14. A composition according to any one of claims 11 to 13, wherein the in the aliphatic or aromatic alcohol is present in the amount of from 1.0 to 20.0 percent by weight of the composition. A composition according to any one of the preceding claims, further comprising less :than 1.0 percent by weight of the composition of an agent selected from a perfume, an odour masking agent, a dye or a pH indicator.

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16. A composition according to any one of the preceding claims, further comprising a chelating agent.

~17. A composition according to claim 16, wherein the chelating agent is tetrasodium thylenediamine tetraacetate.

18. A composition according to any one of claims 1 to 17, which is a solution. •.20

19. A composition according to any one of claims I to 17, which is an emulsion. c

20. A composition according to any one of the preceding claims, which is diluted with from 1 part to 20 parts by volume of water before use.

21. A method of removing dry resinous coatings from a surface comprising the step of applying to said coatings a composition according to any one of claims 1 to

22. A method according to claim 21, wherein the surface is a floor.

23. A method according to claim 21 or claim 22, wherein the composition is applied to the dry resinous coating by means of spray, mop or machine scrubber. DATED this 28th Day of January, 1997 WHITELEY INDUSTRIES PTY. LTD. Attorney: IAN T. ERNST Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS