AU695680B2

AU695680B2 - Concentrated cleaning compositions

Info

Publication number: AU695680B2
Application number: AU64074/94A
Authority: AU
Inventors: Marc Francois Theophile Evers; Peter Rosalia Joannes Geboes; Daniel Wayne Michael; Massimo Morini; Nicola John Policicchio; Vincent Reniers; Louise Gail Scott
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1993-03-19
Filing date: 1994-03-14
Publication date: 1998-08-20
Anticipated expiration: 2014-03-14
Also published as: FI954397A; EP0616027A1; CN1044717C; CN1122610A; WO1994021768A1; CA2158543A1; NO953503D0; NZ263394A; CA2158543C; AU6407494A; BR9406015A; NO953503L; JPH08508766A; FI954397A0

Description

WO 94/21768 PCTIUS94/0Z748 1 CONCENTRATED CLEANING COMPOSITIONS Technical Field The present invention relates to concentrated cleaning compositions. Although the present invention relates primarily to cleaning compositions for hard surfaces, it may also be of interest for other cleaning compositions including dishwashing and laundry detergent compositions.

Background of the Invention Concentrated cleaning compositions are well known in the art. Concentrated compositions are mainly characterized by the fact that they comprise a higher concentration of active ingredients compared to a conventional cleaning composition, and a problem which is typically encountered SUBSTITUTE SHEET (RULE 261 WO 94/21768 PCT/US94/02748 2 when formulating concentrated cleaning compositions is therefore the physical stability of such compositions.

Indeed, because such compositions comprise a high amount of active ingredients in a limited amount of water, stability problems appear which lead, if not solved, to compositions which separate into several phases. This phenomenon affects the performance of the composition and is visually noticeable, thereby rendering such formulations unfit for commercialization.

Various solutions have been proposed to solve this problem which typically involve the use of specific stabilizing ingredients, or hydrotropes. Such ingredients have the sole function of stabilizing the composition. They thus increase the cost of formulating such compositions without providing any cleaning performance benefits, and they furthermore require to free up parts in the formulation which could otherwise be used to formulate more actives.

20 For instance, EP 316 726 discloses concentrated compositions in the form of microemulsions which comprise water, perfume, a surfactant and a so-called co-surfactant.

SThe co-surfactant is said to reduce the interfacial tension at interfaces between dispersed and continuous phases of an emulsion of said surfactant, thereby creating a stable microemulsion. The so-called co-surfactants in the '726 publication are listed as specific glycol ethers, which are traditionally regarded as solvents in this field, or specific carboxylic acids. The co-surfactants in the '726 publication do not appear to participate to the overall cleaning performance of the product.

It would therefore be desirable to formulate a stable concentrated cleaning composition without using ingredients which are provided for the sole purpose of providing stability to the compositions herein, SUBSTITUTE SHEET (RULE 26) I~~a~ae~a~ 3 but which also participate significantly to the cleaning performance of said compositions.

It has now been found that significant advantages in cleaning performance are provided by formulating a concentrated aqueous composition comprising at least one short chain surfactant i.e. with a hydrophobic group consisting of a C 6

-C

10 alkyl chain, said compositions not being in the form of microemulsions. Said short chain surfactants provide stability to the compositions herein and, in the same time, significantly boost the overall cleaning performance, especially grease cleaning, both in neat and dilute useage.

Throughout the description and claims of this specification, the word "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives or components or integers or steps.

Summary of the Invention In accordance with the invention, the compositions herein are stable clear Sconcentrated cleaning compositions comprising from 10% to 80% by weight of the total composition of water and at least one surfactant, wherein said surfactant is a 20 short chain surfactant comprising a C 6

-C

1 o alkyl chain as its hydrophobic portion.

The compositions herein are preferably not in the form of microemulsions.

The present invention provides a stable and clear concentrated cleaning composition comprising by weight: from 5% to 30% of short chain surfactant comprising a mixture of: nonionic surfactant having the formula C6-10(EO)cOH in which c is from 3 to 8; and C6-10 alkyl sulfonate; optionally, long chain surfactant comprising a mixture of: nonionic surfactant having the formula C12-16(EO)nH in which n is from about 2 to about 10; and C IW NORDELI SSAVAL"NDELETENSPEC14O47494. DOC

~LI--W"

nonionic surfactant having the formula C12-16(EO)nH in which n is from 20 to optionally, hydrophobic cleaning solvent having the formula C2-6(EO)x(PO)yOH in which x and y are each from 0 to 2; from 0.5% to 3% suds suppressant comprising a mixture of C8-22 fatty acid and 2-alkyl alkanol; from 1% to 4% potassium carbonate; from 30% to 70% water; and wherein in the above formulae, EO represents an ethoxy moiety and PO represents a propoxy moiety.

The present invention further provides a process of cleaning a hard surface S 15 comprising diluting the composition herein described with water and applying it to o said hard surface.

Detailed Description of the Invention.

The compositions of the present invention are concentrated aqueous compositions. By concentrated, it is meant herein that the compositions comprise from 10% to 90% by weight of the total composition of water, preferably from to 75%, most preferably from 30% to The compositions according to the present invention are clear and stable.

S. By clear and stable, it is meant herein that the compositions of the present invention are macroscopically substantially transparent, in the absence of any opacifier, and that said compositions do not C WINWORD\MELISSAWLHNODELETE.SPEC'640744 DOC rrl?~- lllarur WO 94/21768 PCT/US94/02748 4 macroscopically separate into separate phases during at least 1 month, at temperatures ranging from 4 0 C to 500C, upon standing.

The compositions according to the present invention further comprise at least one short chain surfactant, or mixtures thereof. All surfactants have in common that they comprise a hydrophobic portion and a hydrophilic portion. By short chain surfactant, it is meant herein surfactants which comprise a C6-C10 alkyl chain as their hydrophobic portion.

Such short chain surfactants are accordingly those conventionally used in this field, but with a shorter alkyl chain, and can be of any type. Accordingly, suitable short chain surfactants for use herein include C6-C10 alkyl sulfates (C 6

-CO

1 S0 4 alkyl ether sulfates (C6-

CI

0

(OCH

2

CH

2 )eSO 4 alkyl sulfonates (C 6

-C

10 S0 3 alkyl succinates (C6-C 10 00CCH 2

CH

2 COOZ), alkyl carboxylates (C6-

C

10 COOM), alkyl ether carboxylates (C6-C10(OCH2CH2)eCOOM), alkyl sarcosinates (C 6

-C

1 oCON(CH 3 alkyl sulfo succinates (C 6

-C

10 00CCH(SO 3

M)CH

2 COOZ), amine oxides (C6-

CI

1 RR'NO), glucose amides (C6-C 10 CONR''X), alkyl pyrrolidones (C6-C10(C 4 H60N), alkylpolysaccharides (C6- Cl00Gg), alkyl alkoxylates (C6- CI0(OCH2CH2)e(OCH 2

CH

2

CH

2 )pOH) and betaines (C 6 C1ON+(CH 3 )2CH2COO-). In the formulae in brackets, e and p are independently from 0 to 20 and e+p>0, Z is M or R, M is H or any counterion such as those known in the art, including Na, K, Li, NH 4 amine, X is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an alkoxylated derivative thereof, R, R and are CIalkyl groups, possibly functionalized with hydroxyl groups, R and R' are preferably C1-C3, most preferably methyl, is preferably 2-hydroxyethyl or 2 hydroxypropyl, G is a saccharide, preferably glucose, and g is of from 1.5 to 8. All these surfactants are well known in the art. A more complete disclosure of conventional SUBSTITUTE SHEET (RULE 26) I WO 94/21768 PCT/US94102748 glucose amides can be found for instance in WO 92-06154 and a more complete disclosure of conventional alkyl polysaccharides can be found for instance in US 4,536,319.

The compositions according to the present invention may comprise any of the above surfactants alone, or any combination thereof, depending on the end use envisioned.

Preferred short chain nonionic surfactants for use herein are alkyl alkoxylates according to the formula C 6

C

10

(OCH

2

CH

2 )e(OCH 2

CH

2

CH

2 )pOH, where e and p representing respectively the degree of ethoxylation and propoxylation, are independently of from 0 to 20, and that e+p>0. Most preferred short chain nonionic surfactants for use herein are those where e and p are such that e+p is from 3 to particularly those where p is 0 and e is from 3 to 8.

Also, most preferred short chain nonionic surfactants for use herein are those where said short chain is a hydrocarbon chain comprising from 7 to 10 carbon atoms.

Said preferred short chain nonionic surfactants for use herein can be manufactured by the processes well known to the man skilled in the art, such as condensation of the corresponding alcohol and alkylene oxide, but such short chain surfactants are more conveniently commercially available for instance from Sidobre under the trade name Mergital@C4 (C8E04), from Kolb under the trade names Imbentin@ AG/810/050 and AG/810/080 (respectively C8-10E05 and C8-10E08)* Preferred short chain anionic surfactants for use herein are C 6

-C

10 alkyl sulfates (C 6

-C

10 S04) and alkyl sulfonates

(C

6 -Co 1 S0 3 Most preferred are the C6-C8 alkyl sulfates and sulfonates. The alkyl sulfonates can provide products with less filming/streaking, as demonstrated hereinafter, as compared to other anionics such as alkyl sulfates. Such short chain anionic surfactants can be made by well known sulphation or sulphonation processes followed by neutralization, but said anionic short chain surfactants SUBSTITUTE SHEET (RULE 26) 9 \N'0 94/21768 PCT/US94/02748 6 are more conveniently commercially available, for instance from Rhone Poulenc under the trade name Rhodapon@ OLS, or from Witco under the trade name Witconate@.

The compositions according to the present invention may comprise from 0.1 to 50 by weight of the total composition, preferably from 1% to 40., most preferably from 1.5% to 30% of said short chain surfactants. It has been found that said short chain surfactants allowed the formulation of concentrated compositions without the need for any stabilizing systems, or certain formulation type such as microemulsions. Said short chain surfactants are also particularly effective in cleaning, especially grease cleaning.

The compositions according to the present invention may comprise short chain surfactants only, or combinations of short chain surfactants with conventional longer chain surfactants. Accordingly, suitable long chain surfactants for use herein include those listed herein above in the description of short chain surfactants, but with a longer alkyl chain, of from C 11

-C

24 Preferred long chain surfactants for use herein are long chain alkyl sulfonates, e.g. paraffin sulfonates and alkyl ethoxylates, and mixtures thereof.

If combinations of short chain and long chains are used, it is preferred to observe certain ratios: if short chain anionic surfactants are used, it is preferred to observe a minimum weight ratio of short chain anionic surfactant to longer chain surfactant of 1:10. If short chain nonionic surfactants are used, it is preferred to observe a minimum weight ratio of short chain nonionic to longer chain surfactant of Depending on the end use envisioned, the compositions herein may further comprise a variety of other optional SUBSTITUTE SHEET (RULE 26) -B I ~Y Y Pb IC WO 94/21768 PCT/US94/02748 7 ingredients including builders, alkonolamines, pH adjusting agents, perfumes, dyes, beaches, enzymes and the like. When an alkalinity source is present, it is desirable that the potassium cation be used, when potassium carbonate is used instead of sodium carbonate, as demonstrated hereinafter, there is less filming/streaking. As used herein, potassium carbonate comprises potassium bicarbonate.

The invention therefore also provides a composition as herein described, containing, as an additional ingredient, from about 1% to about 4% potassium carbonate.

In some instances, it may be appropriate to include a suds suppressing system in the compositions herein. Said suds suppressing system can advantageously be a mixture of 2alkyl alkanols as described for instance in DE 40 21 265, or mixtures thereof, with a Cg to C 22 fatty acid, or mixtures thereof. Such a system is particularly advantageous as both ingredients appear to act in synergy.

Thus even a very low amount of said system is enough to control suds efficiently. Accordingly, said system is present in amounts of from 0.1% to 5% by weight of the 20 total composition, preferably 0.5% to 3%.

The compositions herein do not require the presence of a stabilizing compound. By stabilizing compound, it is meant herein a compound whose sole function is to enhance the physical stability of the composition. Such compounds are typically xylene or toluene sulphonate salts, and glycol ethers, including ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol monobutyl ether and other various solvents such as ethanol and butanol. Accordingly, the compositions of the present invention are preferably substantially free of such stabilizing compounds.

The present invention further encompasses a method of cleaning a hard surface which comprises the steps of SUBSTITUTE SHEET (RULE 26) I~ I WO 94/21768 PCT/US94/02748 8 diluting a composition as herein described in water, then applying it to said hard surface. Depending on the exact formulation, the compositions herein may be used both neat and diluted from 10 to 500 times.

Particularly preferred compositions contain: from 5% to of short chain surfactant, preferably a mixture of (a) short chain nonionic surfactant having the formula Cgwherein EO is an ethoxy moiety, PO is a propoxy moiety with each c and p being from 0-20, preferably from 3 to 10, more preferably c being from 3 to 8 and p being 0 and C6- 10 alkyl sulfonate, (2) optional, but preferred, long chain nonionic surfactant, preferably nonionic C12- 16 (EO)n, preferably a mixture of nonionic surfactants in which one has an n of from about 2 to about 10 and the other has an n of from about 20 to about 60; optional hydrophobic cleaning solvent, preferably C2-6(EO)x(PO)yOH wherein x and y are each from 0 S to about 2, and more preferably C 4

(EO)

2 0H; optional, but preferred, fatty acid suds suppressant at a level of from 0.1% to preferably from 0.2% to optional, but preferred, C 12 -1 8 fatty alcohol, more preferably branched chain fatty alcohols such as 2-butyl octanol and/or 2-hexyl decanol; and optional, but preferred, alkalinity source, more preferably potassium carbonate. The balance of each composition is preferably an aqueous solvent system.

The present invention will be further illustrated by the following examples.

Examples The following compositions are made by mixing the listed ingredients in the listed proportions.

SUBSTITUTE SHEET (RULE 26) 4- 111 WO 94/21768 PCT/US94/02748

III

C13/15 alkyl ethoxylate E03

C

12 15 alkyl ethoxylate E0 30

C

8 alkyl sulfate Cg alkyl sulfonate Cg alkyl ethoxylate EO 6 Cg/ 10 alkyl ethoxylate E05 Citric acid Monnethanolamine Triethanolamine Water minors 1 1 1 3 up to All compositions were evaluated for their physical stability at 4°C, at room temperature (20 0 and at 500C.

Composition I, which is not within the invention, was a gel at 4 0 C, and an emulsion at room temperature and at All other compositions, within the invention, were clear transparent liquids in the same conditions.

Other compositions were made by mixing the ingredients in the listed proportions.

listed

VII

5 C13/15 alkyl ethoxylate E03 4 C13/15 alkyl ethoxylate E07 C7-9 alkyl sulfate C8 alkyl sulfate C8 alkyl sulfonate C7-9 alkyl ethoxylate EO6 C8-10 alkyl ethoxylate E05 C13/15 alkyl ethoxylate E030 6 Na Paraffin Sulfonate Citric acid 3

VIII

1 SUBSTITUTE SHEET (RULE 26) ~-a WO 94/21768 PCT/US94/02748 ocdium carbonate 3 2-hexyl decanol 1 0.6 1 Palm Kernel Fatty Acid 0.4 0.4 1 Water minors up to The invention is illustrated by the following examples.

All values in table are weight percentages.

Example No.: 1 2 3 Ingredient Wt% Wt% Wt% Sodium Octyl Sulfate 7.0 Sodium Octyl Sulfonate 7.0 Alfonic R 810-65 10.0 10.0 10.0

(C

8 10 E0 6 average) Neodol R 23-3 4.0 4.0

(C

1 2- 13

EO

3 Lutensol R AO-30 6.0 6.0

(C

13 -1 5

EO

3 0 Sodium Carbonate Potassium Carbonate 2.0 Palm Kernel Fatty Acid 0.4 0.4 0.4 2-Butyl Octanol 0.4 0.4 0G Hydrophobic Perfume* 1.5 1.5 Deionized Water and Minors q.s. q.s. q.s.

pH 10.8 10.8 10.8 Alfonic is a trade name used by Vista Chemical.

Neodol is a trade name used by Shell Chemical Co.

Lutensol is a trade name used by BASF Corp.

*Hydrophobic perfume consists of terpenes, terpene alcohols, and other perfume materials which are typically insoluble in water.

SUBSTITUTE SHEET (RULE 26) I sor'r1440 -r WO 94/21768 PCT/US94/02748 11 The invention is also illustrat by the following Examples. All values in table are weight percentages.

Example No.: 4 Ingredient Wt, WtS Sodium Octyl Sulfonate 7.0 Alfonic R 810-65 10.0 10.0

(C

8 -1 0 E0 6 average) Neodol R 23-3 4.0

(C

12 -1 3 E0 3 Lutensol R AO-30 6.0

(C

1 3- 15 E0 30 Diethylene Glycol Monobutyl Ether Potassium Carbonate 2.0 Palm Kernel Fatty Acid 0.4 0.6 2-Butyl Octanol 0.4 Hydrophobic Perfume* 1.5 Deionized Water and Minors q.s. q.s.

pH 10.5 10.5 Alfonic is a trade name used by Vista Chemical.

Neodol is a trade name used by Shell Chemical Co.

Lutensol is a trade name used by BASF Corp.

Filming/Streaking data were obtained on the above Examples.

Filming/Streaking Test Method -Dilute (No Wax Floors) Materials SUBSTITUTE SHEET (RULE 26) WO 94/21768 PCT/US94/02748 12 1. Spontex cellulose sponges (cut to 2"x4"xl") 2. No wax floor tiles (1 2 x12") 3. Test products these are diluted with heated tap water that has been adjusted to a hardness of 7 grains and maintained at 110 0 F. Dilution is 1 part test product:128 parts water.

Procedure: 1. Clean the floor tiles with tap water using a sponge.

Then rinse with distilled water ard dry with paper towels. Apply a small amount of isopropyl alcohol to each tile and dry thoroughly.

2. Clean sponges of all factory preservatives and rinse well. Use the same sponge for the entire test, rinsing well between change of products. Soak the sponge in the product being tested.

3. Transfer 15 mls of the diluted test product into an inverted sponge carrier.

4. Squeeze out excess product from the sponge and dip the sponge evenly on the flat surface of the carrier, gently squeezing down to soak up the product into the sponge. Tare the sponge on a 2-place balance, product side up.

One tile is used per replicate. The sponge is wiped lighty over the tile surface by drawing an pattern which covers the entire tile as much as possible. Then another is drawn sideways. Place the sponge on the tared balance and record the amount of product applied to the tile.

6. Three replicates are used for each product tested.

SUBSTITUTE SHEET (RULE 26) WO 94/21768 PCT/US94/02748 13 7. Tiles are air dried in air with 52% relative humidity at room temperature (about 24°C) for approximately one hour.

8. Three expert graders grade the panels on the following scale system: 0 no filming/streaking 6 very poor filming/streaking Grades are averages for each product..

Filming/Streaking Data Formula No. Filming/Streaking Mean Grade 1.4 1.8 2.1 The LSD for this test was 0.2 at the 95% Confidence Interval, therefore the Filming/Streaking mean values achieved for each formula are statistically distinct from one another. The superior Filming/Streaking result was achieved through a combination of both the octyl sulfonate (3 vs 1) and the potassium carbonate (3 vs 2).

SUBSTITUTE SHEET (RULE 26)

Claims

1. A stable and clear concentrated cleaning composition comprising by weight: from 5% to 30% of short chain surfactant comprising a mixture of: nonionic surfactant having the formula C6-10(EO)cOH in which c is from 3 to 8; and C6-10 alkyl sulfonate; optionally, long chain surfactant comprising a mixture of: nonionic surfactant having the formula C12-16(EO)nH in which n is from about 2 to about 10; and nonionic surfactant having the formula C12-16(EO)nH in which n is from 20 to 15 optionally, hydrophobic cleaning solvent having the formula C2-6(EO)x(PO)yOH in which x and y are each from 0 to 2; from 0.5% to 3% suds suppressant comprising a mixture of C8-22 fatty acid and 2-alkyl alkanol; from 1% to 4% potassium carbonate; 20 from 30% to 70% water; and wherein in the above formulae, EO represents an ethoxy moiety and PO represents a propoxy moiety.

2. The composition of claim 1 which is substantially free of stabilizing compounds.

3. A process of cleaning a hard surface comprising diluting the composition of claim 1 with water and applying it to said hard surface.

4. A stable and clear concentrated cleaning composition according to claim 1, substantially as hereinbefore described, with reference to any one of the Examples. C %WNWORDMELISSAWLH\NODELVEESPECM4O74A94 DC A process according to claim 3, substantially as hereinbefore described, with reference to any one of the Examples. DATED: 2July 1998 PHILLIPS ORMONDE FITZPATRICK Attorneys for: THE PROCTER GAMBLE COMPANY C 'WMNWCRDWELISSAWXMODELETEVSPECM%4074A94-DOC INTERNATIONAL SEARCH REPORT International application No. PCT/US94/02748 A. CLASSIFICATION OF SUBJECT MATTER Please See Extra Sheet. US CL :Please See Extra Sheet. According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) U.S. 252/173, 174.21, 174.22, 550, 551, 552, 553, 554, 555, 556, 557, 558, 559, DIG. 14. Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched NONE Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) NONE C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X US, A, 4,671,895 (ERILLI ET AL.) 09 June 1987 see abstract; col. 4, lines 3-22; Example A in col. 4; col. 4, lines Y 46-47. Y US, A, 5,057,246 (BERTHO ET AL.) 15 October 1991 see abstract; col. 3, lines 35-66; col.

5, lines 32-56. A US, A, 4,235,758 (DAWSON ET AL.) 25 November 1980 see abstract and examples. D Further documents are listed in the continuation of Box C. See patent family annex. Special categona of cited documents: "T later document publlhed after the internauonal filing date or prority date and not in conflict wih the application but cited to understand the document defining the general state of the art which is not considered principle or theory underlying the invention to be of partcular relevance SE r doc pbhed on or the nt ona fiing date X document of particular relevance: the claimed invention cannot be arler document publhed on or after the intnional filing dae conidered novel or cannot be coidered to involve an inventve .tep document which may throw doubts on priority claim(s) or which i when the document taken alone cited to etablish the publication date of another citation or other special reason (as apecified) Y" document of particular relevance: the claimed invention cannot be considered to involve an inventive itep when the doctuncnt is document referrng to an orl disclosure, use, exhibition or other combined with one or more other such document., such combnation means being obvious to a pernol akilled in the art document publulhed pnor to the ineruonal filing date but later than document member of the saine patent family the pnonry date claimed Date of the. actual completion of the international search Date of mailing.of the international search report 29 APRIL 1994 18 MAY 1994 Name and mailing address of the ISA/US Authorized ofi Cuommissioner oul Patents and Trademarks Box PCT 'PAUL LIEBERMAN Washington, D.C. 20231 Facsimile No. (703) 305-3230 Telephone No. (703) 308-0661 Form PCT/ISA/210 (second shcct)(July 1992)* 111111 d r INTERNATIONAL SEARCH REPORT int...,ational application No. PCTIUS94/02748 Box 1 Observations where certain claims were found unsearchable (Continuation of item I of first sheet) This international report has not been established in respect of certain claims under Article 17(2)(a) for the following reasons: 1 Claims Nos.: S because they relate to subject matter not required to be searched by this Authority, namely: 2. Claims Nos.: because they relate to parts of the international application that do not comply with the prescribed requirements to such an extent that no meaningful international search can be carried out, specifically: 3. Claims Nos.: 6-15 because they are dependent claims and are not drafted in accordance with the second and third sentences of Rule 6.4(a). Box II Observations where unity of invention is lacking (Continuation of item 2 of first sheet) This International Searching Authority found multiple inventions in this international application, as follows: 1. [7 As all required additional search fees were timely paid by the applicant, this international search report covers all searchable claims. 2. O As all searchable claims could be searched without effort justifying an additional fee, this Authority did not invite payment of any additional fee. 3 As only some of the required additional search fees were timely paid by the applicant, this international search report covers only those claims for which fees were paid, specifically claims Nos.: 4. O No required additional search fees were timely paid by the applicant. Consequently, this international search report is restricted to the invention first mentioned in the claims; it is covered by claims Nos.: Remark on Protest D The additional search fees were accompanied by the applicant's protest. D No protest accompanied the payment of additional search fees. :orrn PCT/ISA/210 (continuation of first sheet(l))0uly 1992)* Form PCT/ISAI210 (continuation of first sheet(l))(July 1992)* I I NTERNATIONAL SEARCH REPORT Internatonal application No. PCT/US94/02748 A. CLASSIFICATION OF SUBJECT MATTER: I PC CUIID 1/ 14, 1/16, 1/22, 1/24, 1/28, 1/29, 1/37, 1/72, 1/722, 1/83, 1/831, 17/00, 17/08. A. CLASSIFICATION OF SUBJECT MATTER: US CL. 252/173, 174.21, 174.22, 550, 551, 552, 553, 554, 555, 556, 557, 558, 559, DIG. 14. I Form PCT/ISA1210 (extra shect)(iuly 1992)*