An acidic hard surface liquid detergent with desirable cleansing and antibacterial properties comprises a C8-18 anionic surfactant, nonionic surfactants, a cosurfactant, water insoluble hydrocarbon, essential oil or perfume, a hydroxy aliphatic acid and/or salicylic acid and water.

This invention relates to an acidic all purpose liquid cleaning composition which can be in the form of a microemulsion designed in particular for cleaning hard surfaces and which is effective in removing grease soil and/or bath soil in leaving unrinsed surfaces with a shiny appearance.
This invention relates to an improved all-purpose liquid cleaning composition or a microemulsion composition designed in particular for cleaning hard surfaces and which is effective in removing grease soil and/or bath soil and in leaving unrinsed surfaces with a shiny appearance.
In recent years all-purpose liquid detergents have become widely accepted for cleaning hard surfaces, e.g., painted woodwork and panels, tiled walls, wash bowls, bathtubs, linoleum or tile floors, washable wall paper, etc. Such all-purpose liquids comprise clear and opaque aqueous mixtures of water-soluble synthetic organic detergents and water-soluble detergent builder salts. In order to achieve comparable cleaning efficiency with granular or powdered all-purpose cleaning compositions, use of water-soluble inorganic phosphate builder salts was favored in the prior art all-purpose liquids. For example, such early phosphate-containing compositions are described in U.S. Pat. Nos. 2,560,839; 3,234,138; 3,350,319; and British Patent No. 1,223,739.
In view of the environmentalist""s efforts to reduce phosphate levels in ground water, improved all-purpose liquids containing reduced concentrations of inorganic phosphate builder salts or non-phosphate builder salts have appeared. A particularly useful self-opacified liquid of the latter type is described in U.S. Pat. No. 4,244,840.
However, these prior art all-purpose liquid detergents containing detergent builder salts or other equivalent tend to leave films, spots or streaks on cleaned unrinsed surfaces, particularly shiny surfaces. Thus, such liquids require thorough rinsing of the cleaned surfaces which is a time-consuming chore for the user.
In order to overcome the foregoing disadvantage of the prior art all-purpose liquid, U.S. Pat. No. 4,017,409 teaches that a mixture of paraffin sulfonate and a reduced concentration of inorganic phosphate builder salt should be employed. However, such compositions are not completely acceptable from an environmental point of view based upon the phosphate content. On the other hand, another alternative to achieving phosphate-free all-purpose liquids has been to use a major proportion of a mixture of anionic and nonionic detergents with minor amounts of glycol ether solvent and organic amine as shown in U.S. Pat. No. 3,935,130. Again, this approach has not been completely satisfactory and the high levels of organic detergents necessary to achieve cleaning cause foaming which, in turn, leads to the need for thorough rinsing which has been found to be undesirable to today""s consumers.
Another approach to formulating hard surfaced or all-purpose liquid detergent composition where product homogeneity and clarity are important considerations involves the formation of oil-in-water (o/w) microemulsions which contain one or more surface-active detergent compounds, a water-immiscible solvent (typically a hydrocarbon solvent), water and a xe2x80x9ccosurfactantxe2x80x9d compound which provides product stability. By definition, an o/w microemulsion is a spontaneously forming colloidal dispersion of xe2x80x9coilxe2x80x9d phase particles having a particle size in the range of 25 to 800 xc3x85 in a continuous aqueous phase.
In view of the extremely fine particle size of the dispersed oil phase particles, microemulsions are transparent to light and are clear and usually highly stable against phase separation.
Patent disclosures relating to use of grease-removal solvents in o/w microemulsions include, for example, European Patent Applications EP 0137615 and EP 0137616xe2x80x94Herbots et al; European Patent Application EP 0160762xe2x80x94Johnston et al; and U.S. Pat. No. 4,561,991xe2x80x94Herbots et al. Each of these patent disclosures also teaches using at least 5% by weight of grease-removal solvent.
It is also known from British Patent Application GB 2144763A to Herbots et al, published Mar. 13, 1985, that magnesium salts enhance grease-removal performance of organic grease-removal solvents, such as the terpenes, in o/w microemulsion liquid detergent compositions. The compositions of this invention described by Herbots et al. require at least 5% of the mixture of grease-removal solvent and magnesium salt and preferably at least 5% of solvent (which may be a mixture of water-immiscible non-polar solvent with a sparingly soluble slightly polar solvent) and at least 0.1% magnesium salt.
However, since the amount of water immiscible and sparingly soluble components which can be present in an o/w microemulsion, with low total active ingredients without impairing the stability of the microemulsion is rather limited (for example, up to 18% by weight of the aqueous phase), the presence of such high quantities of grease-removal solvent tend to reduce the total amount of greasy or oily soils which can be taken up by and into the microemulsion without causing phase separation.
The following representative prior art patents also relate to liquid detergent cleaning compositions in the form of o/w microemulsions: U.S. Pat. No. 4,472,291xe2x80x94Rosario; U.S. Pat. No. 4,540,448xe2x80x94Gauteer et al; U.S. Pat. No. 3,723,330xe2x80x94Sheflin; etc.
Liquid detergent compositions which include terpenes, such as d-limonene, or other grease-removal solvent, although not disclosed to be in the form of o/w microemulsions, are the subject matter of the following representative patent documents: European Patent Application 0080749; British Patent Specification 1,603,047; and U.S. Pat. Nos. 4,414,128 and 4,540,505. For example, U.S. Pat. No. 4,414,128 broadly discloses an aqueous liquid detergent composition characterized by, by weight:
(a) from 1% to 20% of a synthetic anionic, nonionic, amphoteric or zwitterionic surfactant or mixture thereof;
(b) from 0.5% to 10% of a mono- or sesquiterpene or mixture thereof, at a weight ratio of (a):(b) being in the range of 5:1 to 1:3; and
(c) from 0.5% 10% of a polar solvent having a solubility in water at 15xc2x0 C. in the range of from 0.2% to 10%. Other ingredients present in the formulations disclosed in this patent include from 0.05% to 2% by weight of an alkali metal, ammonium or alkanolammonium soap of a C13-C24 fatty acid; a calcium sequestrant from 0.5% to 13% by weight; non-aqueous solvent, e.g., alcohols and glycol ethers, up to 10% by weight; and hydrotropes, e.g., urea, ethanolamines, salts of lower alkylaryl sulfonates, up to 10% by weight. All of the formulations shown in the Examples of this patent include relatively large amounts of detergent builder salts which are detrimental to surface shine.
Furthermore, the present inventors have observed that in formulations containing grease-removal assisting magnesium compounds, the addition of minor amounts of builder salts, such as alkali metal polyphosphates, alkali metal carbonates, nitrilotriacetic acid salts, and so on, tends to make it more difficult to form stable microemulsion systems.
U.S. Pat. No. 5,082,584 discloses a microemulsion composition having an anionic surfactant, a cosurfactant, nonionic surfactant, perfume and water; however, these compositions do not possess the ecotoxicity and the improved interfacial tension properties as exhibited by the compositions of the instant invention.
A number of patents teach esterified ethoxylated glycerol compounds for various applications. These patents are Great Britain 1,453,385; Japan 59-1600 and Japan 58-206693 and European Patent Application 0586,323A1. These publications fail to appreciate that a mixture of esterified ethoxylated glycerol and nonesterified ethoxylated glycerol, when used in a hard surface cleaning composition, functions as a grease release agent.
It has now been found that an acid hard surface liquid detergent can be formulated with an anionic surfactant which has desirable cleaning properties.
An object of this invention is to provide an acidic hard surface liquid detergent composition which can be in the form of a microemulsion, and comprises a sulfate and/or sulfonate anionic surfactant, at least one nonionic surfactant, triethanol amine, a glycol ether cosurfactant, a water insoluble organic compound, at least one hydroxy aliphatic acid salicylic acid and water, wherein the composition does not contain any ethoxylated polyhydric alochol type compounds, N-alkyl aldonamide, zwitterionic surfactant, silicas, abrasives, alkali metal carbonates, alkaline earth metal carbonates, alkyl glycine surfactant or a cyclic imidinium surfactant.
Another object of this invention is to provide an acidic hard surface liquid detergent with desirable cleaning properties which kills bacteria.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The microemulsion hard surface liquid compositions of the instant invention comprises approximately by weight:
(a) 0.1% to 20% of an anionic surfactant;
(b) 0.1% to 3% of triethanol amine;
(c) 0.1% to 10% of at least one nonionic surfactant;
(d) 0 to 5% of polyethylene glycol;
(e) 0.1% to 6% of at least one hydroxy aliphatic acid;
(f) 0.1% to 5% of salicylic acid;
(g) 0 to 10% of at least one solubilizing agent;
(h) 0.1% to 15% of at least one cosurfactant;
(i) 0 to 15% of an inorganic magnesium salt;
(j) 0% to 2% of a fatty acid;
(k) 0.1% to 10% of perfume, essential oil, a water insoluble organic compound such as an ester or a water insoluble material such as terpene or essential oils; and
(l) the balance being water.
The instant compositions do not contain an N-alkyl aldonamide, an ethoxylated polyhydric alcohol type compound, choline chloride or buffering system which is a nitrogenous buffer which is ammonium or alkaline earth carbonate, guanidine derivates, alkoxylalkyl amines and alkyleneamines C3-C7 alkyl and alkenyl monobasic and dibasic acids such as C4-C7 aliphatic carboxylic diacids which do not contain a hydroxy group, and the composition is pourable and is not a gel and the composition has a complex viscosity at 1 rads-1 of less than 0.4 Pascal seconds.
The anionic sulfonate surfactants which may be used in the detergent of this invention are water soluble and include the sodium, potassium, ammonium and ethanolammonium salts of linear C8-C16 alkyl benzene sulfonates; C10-C20 paraffin sulfonates, alpha olefin sulfonates containing about 10-24 carbon atoms, C8-C16 alkyl sulfate and C8-C18 ethoxylated alkyl ether sulfates and mixtures thereof. The preferred anionic surfactant is a C12 alkyl sulfate.
The paraffin sulfonates may be monosulfonates or di-sulfonates and usually are mixtures thereof, obtained by sulfonating paraffins of 10 to 20 carbon atoms. Preferred paraffin sulfonates are those of C12-18 carbon atoms chains, and more preferably they are of C14-17 chains. Paraffin sulfonates that have the sulfonate group(s) distributed along the paraffin chain are described in U.S. Pat. Nos. 2,503,280; 2,507,088; 3,260,744; and U.S. Pat. No. 3,372,188; and also in German Patent 735,096. Such compounds may be made to specifications and desirably the content of paraffin sulfonates outside the C14-17 range will be minor and will be minimized, as will be any contents of di- or poly-sulfonates.
Examples of suitable other sulfonated anionic detergents are the well known higher alkyl mononuclear aromatic sulfonates, such as the higher alkylbenzene sulfonates containing 9 to 18 or preferably 9 to 16 carbon atoms in the higher alkyl group in a straight or branched chain, or C8-15 alkyl toluene sulfonates. A preferred alkylbenzene sulfonate is a linear alkylbenzene sulfonate having a higher content of 3-phenyl (or higher) isomers and a correspondingly lower content (well below 50%) of 2-phenyl (or lower) isomers, such as those sulfonates wherein the benzene ring is attached mostly at the 3 or higher (for example 4, 5, 6 or 7) position of the alkyl group and the content of the isomers in which the benzene ring is attached in the 2 or 1 position is correspondingly low. Preferred materials are set forth in U.S. Pat. No. 3,320,174, especially those in which the alkyls are of 10 to 13 carbon atoms.
The C8-18 ethoxylated alkyl ether sulfate surfactants have the structure
Rxe2x80x94(OCHCH2)nOSO3xe2x88x92M+
wherein n is about 1 to about 22 more preferably 1 to 3 and R is an alkyl group having about 8 to about 18 carbon atoms, more preferably 12 to 15 and natural cuts, for example, C12-14 or C12-16 and M is an ammonium cation or a metal cation, most preferably sodium.
The ethoxylated alkyl ether sulfate may be made by sulfating the condensation product of ethylene oxide and C8-10 alkanol, and neutralizing the resultant product. The ethoxylated alkyl ether sulfates differ from one another in the number of carbon atoms in the alcohols and in the number of moles of ethylene oxide reacted with one mole of such alcohol. Preferred ethoxylated alkyl ether polyethenoxy sulfates contain 12 to 15 carbon atoms in the alcohols and in the alkyl groups thereof, e.g., sodium myristyl (3 EO) sulfate.
Ethoxylated C8-18 alkylphenyl ether sulfates containing from 2 to 6 moles of ethylene oxide in the molecule are also suitable for use in the invention compositions. These detergents can be prepared by reacting an alkyl phenol with 2 to 6 moles of ethylene oxide and sulfating and neutralizing the resultant ethoxylated alkylphenol.
The water soluble nonionic surfactants which are utilized in this invention are commercially well known and include the primary aliphatic alcohol ethoxylates, secondary aliphatic alcohol ethoxylates, alkylphenol ethoxylates and ethylene-oxide-propylene oxide condensates on primary alkanols, such a Plurafacs (BASF) and condensates of ethylene oxide with sorbitan fatty acid esters such as the Tweens (ICI). The nonionic synthetic organic detergents generally are the condensation products of an organic aliphatic or alkyl aromatic hydrophobic compound and hydrophilic ethylene oxide groups. Practically any hydrophobic compound having a carboxy, hydroxy, amido, or amino group with a free hydrogen attached to the nitrogen can be condensed with ethylene oxide or with the polyhydration product thereof, polyethylene glycol, to form a water-soluble nonionic detergent. Further, the length of the polyethenoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.
The nonionic detergent class includes the condensation products of a higher alcohol (e.g., an alkanol containing 8 to 18 carbon atoms in a straight or branched chain configuration) condensed with 5 to 30 moles of ethylene oxide, for example, lauryl or myristyl alcohol condensed with 16 moles of ethylene oxide (EO), tridecanol condensed with 6 to moles of EO, myristyl alcohol condensed with about 10 moles of EO per mole of myristyl alcohol, the condensation product of EO with a cut of coconut fatty alcohol containing a mixture of fatty alcohols with alkyl chains varying from 10 to 14 carbon atoms in length and wherein the condensate contains either 6 moles of EO per mole of total alcohol or 9 moles of EO per mole of alcohol and tallow alcohol ethoxylates containing 6 EO to 11 EO per mole of alcohol.
A preferred group of the foregoing nonionic surfactants are the Neodol ethoxylates (Shell Co.), which are higher aliphatic, primary alcohols containing about 9-15 carbon atoms, such as C9-C11 alkanol condensed with 8 moles of ethylene oxide (Neodol 91-8), C12-13 alkanol condensed with 6.5 moles ethylene oxide (Neodol 23-6.5), C12-15 alkanol condensed with 12 moles ethylene oxide (Neodol 25-12), C14-C15 alkanol condensed with 13 moles ethylene oxide (Neodol 45-13), and the like.
Additional satisfactory water soluble alcohol ethylene oxide condensates are the condensation products of a secondary aliphatic alcohol containing 8 to 18 carbon atoms in a straight or branched chain configuration condensed with 5 to 30 moles of ethylene oxide. Examples of commercially available nonionic detergents of the foregoing type are C11-C15 secondary alkanol condensed with either 9 EO (Tergitol 15-S-9) or 12 EO (Tergitol 15-S-12) marketed by Union Carbide.
Also among the satisfactory nonionic detergents are the water-soluble condensation products of a C8-C20 alkanol with a heteric mixture of ethylene oxide and propylene oxide wherein the weight ratio of ethylene oxide to propylene oxide is from 2.5:1 to 4:1, preferably 2.8:1-3.3:1, with the total of the ethylene oxide and propylene oxide (including the terminal ethanol or propanol group) being from 60-85%, preferably 70-80%, by weight. Such detergents are commercially available from BASF-Wyandotte and a particularly preferred detergent is a C10-C16 alkanol condensate with ethylene oxide and propylene oxide, the weight ratio of ethylene oxide to propylene oxide being 3:1 and the total alkoxy content being 75% by weight.
Other suitable water-soluble nonionic detergents which are less preferred are marketed under the trade name xe2x80x9cPluronics.xe2x80x9d The compounds are formed by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The molecular weight of the hydrophobic portion of the molecule is of the order of 950 to 4000 and preferably 200 to 2,500. The addition of polyoxyethylene radicals to the hydrophobic portion tends to increase the solubility of the molecule as a whole so as to make the surfactant water-soluble. The molecular weight of the block polymers varies from 1,000 to 15,000 and the polyethylene oxide content may comprise 20% to 80% by weight. Preferably, these surfactants will be in liquid form and satisfactory surfactants are available as grades L62 and L64. The most preferred nonionic surfactant system is a mixture of Neodol 91-2.5 and Neodol 91-8.
Also water soluble nonionic surfactants can be utilized in this invention which are an aliphatic ethoxylated/propoxylated nonionic surfactants which are depicted by the formula:
Rxe2x80x94O"Parenopenst"CH2CH2O"Parenclosest"x"Parenopenst"CH2CH2CH2O"Parenclosest"yxe2x80x94H
or
wherein R is a branched chain alkyl group having about 10 to about 16 carbon atoms, preferably an isotridecyl group and x and y are independently numbered from 1 to 20. A preferred ethoxylated/propoxylated nonionic surfactant is Pluraface(copyright) 300 manufactured by BASF.
The at least one hydroxy aliphatic acid is used in the nonmicroemulsion or microemulsion composition at a concentration of about 0.1 wt. % to about 6 wt. %. The hydroxy aliphatic acid used in the instant composition is selected from the group consisting of glycolic acid, tartaric acid, citric acid and lactic acid and mixtures thereof.
As used herein and in the appended claims the term xe2x80x9cperfumexe2x80x9d is used in its ordinary sense to refer to and include any non-water soluble fragrant substance or mixture of substances including natural (i.e., obtained by extraction of flower, herb, blossom or plant), artificial (i.e., mixture of natural oils or oil constituents) and synthetically produced substance) odoriferous substances. Typically, perfumes are complex mixtures of blends of various organic compounds such as alcohols, aldehydes, ethers, aromatic compounds and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight, the essential oils themselves being volatile odoriferous compounds and also serving to dissolve the other components of the perfume.
In the present invention the precise composition of the perfume is of no particular consequence to cleaning performance so long as it meets the criteria of water immiscibility and having a pleasing odor. Naturally, of course, especially for cleaning compositions intended for use in the home, the perfume, as well as all other ingredients, should be cosmetically acceptable, i.e., non-toxic, hypoallergenic, etc. The instant compositions show a marked improvement in ecotoxocity as compared to existing commercial products.
Suitable essential oils are selected from the group consisting of: Anethole 20/21 natural, Aniseed oil china star, Aniseed oil globe brand, Balsam (Peru), Basil oil (India), Black pepper oil, Black pepper oleoresin 40/20, Bois de Rose (Brazil) FOB, Borneol Flakes (China), Camphor oil, White, Camphor powder synthetic technical, Cananga oil (Java), Cardamom oil, Cassia oil (China), Cedarwood oil (China) BP, Cinnamon bark oil, Cinnamon leaf oil, Citronella oil, Clove bud oil, Clove leaf, Coriander (Russia), Coumarin 69xc2x0 C. (China), Cyclamen Aldehyde, Diphenyl oxide, Ethyl vanilin, Eucalyptol, Eucalyptus oil, Eucalyptus citriodora, Fennel oil, Geranium oil, Ginger oil, Ginger oleoresin (India), White grapefruit oil, Guaiacwood oil, Gurjun balsam, Heliotropin, Isobornyl acetate, Isolongifolene, Juniper berry oil, L-methyl acetate, Lavender oil, Lemon oil, Lemongrass oil, Lime oil distilled, Litsea Cubeba oil, Longifolene, Menthol crystals, Methyl cedryl ketone, Methyl chavicol, Methyl salicylate, Musk ambrette, Musk ketone, Musk xylol, Nutmeg oil, Orange oil, Patchouli oil, Peppermint oil, Phenyl ethyl alcohol, Pimento berry oil, Pimento leaf oil, Rosalin, Sandalwood oil, Sandenol, Sage oil, Clary sage, Sassafras oil, Spearmint oil, Spike lavender, Tagetes, Tea tree oil, Vanilin, Vetyver oil (Java), Wintergreen, Allocimene, Arbanex(trademark), Arbanol(copyright), Bergamot oils, Camphene, Alpha-Campholenic aldehyde, I-Carvone, Cineoles, Citral, Citronellol Terpenes, Alpha-Citronellol, Citronellyl Acetate, Citronellyl Nitrile, Para-Cymene, Dihydroanethole, Dihydrocarveol, d-Dihydrocarvone, Dihydrolinalool, Dihydromyrcene, Dihydromyrcenol, Dihydromyrcenyl Acetate, Dihydroterpineol, Dimethyloctanal, Dimethyloctanol, Dimethyloctanyl Acetate, Estragole, Ethyl-2 Methylbutyrate, Fenchol, Fernlol(trademark), Florilys(trademark), Geraniol, Geranyl Acetate, Geranyl Nitrile, Glidmint(trademark) Mint oils, Glidox(trademark), Grapefruit oils, trans-2-Hexenal, trans-2-Hexenol, cis-3-Hexenyl Isovalerate, cis-3-Hexanyl-2-methylbutyrate, Hexyl Isovalerate, Hexyl-2-methylbutyrate, Hydroxycitronellal, Ionone, Isobornyl Methylether, Linalool, Linalool Oxide, Linalyl Acetate, Menthane Hydroperoxide, I-Methyl Acetate, Methyl Hexyl Ether, Methyl-2-methylbutyrate, 2-Methylbutyl Isovalerate, Myrcene, Nerol, Neryl Acetate, 3-Octanol, 3-Octyl Acetate, Phenyl Ethyl-2-methylbutyrate, Petitgrain oil, cis-Pinane, Pinane Hydroperoxide, Pinanol, Pine Ester, Pine Needle oils, Pine oil, alpha-Pinene, beta-Pinene, alpha-Pinene Oxide, Plinol, Plinyl Acetate, Pseudo lonone, Rhodinol, Rhodinyl Acetate, Spice oils, alpha-Terpinene, gamma-Terpinene, Terpinene-4-OL, Terpineol, Terpinolene, Terpinyl Acetate, Tetrahydrolinalool, Tetrahydrolinalyl Acetate, Tetrahydromyrcenol, Tetralol(copyright), Tomato oils, Vitalizair, Zestoral(trademark).
The polyethylene glycol which can be used in the instant composition has a molecular weight of 200 to 1,000, wherein the polyethylene glycol has the structure
HO(CH2CH2O)nH
wherein n is 4 to 25. The concentration of the polyethylene glycol in the instant composition is 0 to 5 wt. %, more preferably 0.1 to 4.0 wt. %.
The instant all purpose cleaning compositions contain about 0 wt. % to about 10 wt. %, of at least one solubilizing agent selected from the group consisting of a C2-5 mono, dihydroxy or polyhydroxy alkanols such as ethanol, isopropanol, glycerol ethylene glycol, diethylene glycol and propylene glycol and mixtures thereof and alkali metal cumene or xylene sulfonates such as sodium cumene sulfonate and sodium xylene sulfonate. The solubilizing agents are included in order to control low temperature cloud clear properties.
The cosurfactant used in the microemulsion composition may play an essential role in the formation of the microemulsion compositions. Very briefly, in the absence of the cosurfactant the water, detergent(s) and hydrocarbon (e.g., perfume) will, when mixed in appropriate proportions form either a micellar solution (low concentration) or form an oil-in-water emulsion in the first aspect of the invention. With the cosurfactant added to this system, the interfacial tension at the interface between the emulsion droplets and aqueous phase is reduced to a very low value. This reduction of the interfacial tension results in spontaneous break-up of the emulsion droplets to consecutively smaller aggregates until the state of a transparent colloidal sized emulsion. e.g., a microemulsion, is formed. In the state of a microemulsion, thermodynamic factors come into balance with varying degrees of stability related to the total free energy of the microemulsion. Some of the thermodynamic factors involved in determining the total free energy of the system are (1) particle-particle potential; (2) interfacial tension or free energy (stretching and bending); (3) droplet dispersion entropy; and (4) chemical potential changes upon formation. A thermodynamically stable system is achieved when (2) interfacial tension or free energy is minimized and (3) droplet dispersion entropy is maximized.
Thus, the role of cosurfactant in formation of a stable o/w microemulsion is to (a) decrease interfacial tension (2); and (b) modify the microemulsion structure and increase the number of possible configurations (3). Also, the cosurfactant will (c) decrease the rigidity. Generally, an increase in cosurfactant concentration results in a wider temperature range of the stability of the product.
The major class of compounds found to provide highly suitable cosurfactants for the microemulsion over temperature ranges extending from 5xc2x0 C. to 43xc2x0 C. for instance are polypropylene glycol of the formula HO(CH3CHCH2O)nH wherein n is a number from 1 to 18, and mono and di C1-C6 alkyl ethers and esters of ethylene glycol and propylene glycol having the structural formulas R(X)nOH, R1(X)nOH, R(X)nOR and R1(X)nOR1 wherein R is C1-C6 alkyl group, R1 is C2-C4 acyl group, X is (OCH2CH2) or (OCH2(CH3)CH) and n is a number from 1 to 4, diethylene glycol, triethylene glycol, an alkyl lactate, wherein the alkyl group has 1 to 6 carbon atoms, 1methoxy-2-propanol, 1methoxy-3-propanol, and 1methoxy 2-, 3- or 4-butanol.
Representative members of the polypropylene glycol include dipropylene glycol and polypropylene glycol having a molecular weight of 150 to 1000, e.g., polypropylene glycol 400. Other satisfactory glycol ethers are ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monobutyl ether, mono, di, tri propylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, mono, di, tripropylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, propylene glycol tertiary butyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monopropyl ether, ethylene glycol monopentyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monopentyl ether, triethylene glycol monohexyl ether, mono, di, tripropylene glycol monoethyl ether, mono, di tripropylene glycol monopropyl ether, mono, di, tripropylene glycol monopentyl ether, mono, di, tripropylene glycol monohexyl ether, mono, di, tributylene glycol mono methyl ether, mono, di, tributylene glycol monoethyl ether, mono, di, tributylene glycol monopropyl ether, mono, di, tributylene glycol monobutyl ether, mono, di, tributylene glycol monopentyl ether and mono, di, tributylene glycol monohexyl ether, ethylene glycol monoacetate and dipropylene glycol propionate. When these glycol type cosurfactants are at a concentration of about 0.5 to about 14 weight %, more preferably about 2.0 weight % to about 10 weight % in combination with a water insoluble organic ester or non water soluble material such as terpene, essential oils which is at a concentration of at least 0.5 weight %, more preferably 1.5 weight % to about 8 wt. % one can form a microemulsion composition.
While all of the aforementioned glycol ether compounds provide the described stability, the most preferred cosurfactant compounds of each type, is diethylene glycol monobutyl ether. Other suitable water soluble cosurfactants are water soluble esters such as ethyl lactate and water soluble carbohydrates such as butyl glycosides.
The instant formulas explicitly exclude alkali metal silicates and alkali metal builders such as alkali metal polyphosphates, alkali metal carbonates and alkali metal phosphonates because these materials, if used in the instant composition, would cause the composition to have a high pH as well as leaving residue on the surface being cleaned.
The final essential ingredient in the inventive microemulsion or nonmicroemulsion compositions having improved interfacial tension properties is water.
In addition to the above-described essential ingredients required for the formation of the microemulsion composition, the compositions of this invention may often and preferably do contain one or more additional ingredients which serve to improve overall product performance.
One such ingredient is an inorganic or organic salt of oxide of a multivalent metal cation, particularly Mg++. The metal salt or oxide provides several benefits including improved cleaning performance in dilute usage, particularly in soft water areas, and minimized amounts of perfume required to obtain the microemulsion state. Magnesium sulfate, either anhydrous or hydrated (e.g., heptahydrate), is especially preferred as the magnesium salt. Good results also have been obtained with magnesium oxide, magnesium chloride, magnesium acetate, magnesium propionate and magnesium hydroxide. These magnesium salts can be used with formulations at neutral or acidic pH since magnesium hydroxide will not precipitate at these pH levels.
Although magnesium is the preferred multivalent metal from which the salts (inclusive of the oxide and hydroxide) are formed, other polyvalent metal ions also can be used provided that their salts are nontoxic and are soluble in the aqueous phase of the system at the desired pH level.
When needed, the compositions can include from 0% to 2.5% by weight of the composition of a C8-C22 fatty acid or fatty acid soap as a foam suppressant.
The addition of fatty acid or fatty acid soap provides an improvement in the rinseability of the composition whether applied in neat or diluted form. Generally, however, it is necessary to increase the level of cosurfactant to maintain product stability when the fatty acid or soap is present. If more than 2.5 wt. % of a fatty acid is used in the instant compositions, the composition will become unstable at low temperatures as well as having an objectionable smell.
As example of the fatty acids which can be used as such or in the form of soap, mention can be made of distilled coconut oil fatty acids, xe2x80x9cmixed vegetablexe2x80x9d type fatty acids (e.g. high percent of saturated, mono-and/or polyunsaturated C18 chains); oleic acid, stearic acid, palmitic acid, eiocosanoic acid, and the like, generally those fatty acids having from 8 to 22 carbon atoms being acceptable.
Thus, depending on such factors as the pH of the system, the nature of the primary surfactants and cosurfactant, and so on, as well as the availability and cost factors, other suitable polyvalent metal ions include aluminum, copper, nickel, iron, calcium, etc. It should be noted, for example, that with the preferred paraffin sulfonate anionic detergent calcium salts will precipitate and should not be used. It has also been found that the aluminum salts work best at pH below 5 or when a low level, for example 1 weight percent, of citric acid is added to the composition which is designed to have a neutral pH. Alternatively, the aluminum salt can be directly added as the citrate in such case. As the salt, the same general classes of anions as mentioned for the magnesium salts can be used, such as halide (e.g., bromide, chloride), sulfate, nitrate, hydroxide, oxide, acetate, propionate, etc.
Preferably, in the dilute compositions the metal compound is added to the composition in an amount sufficient to provide at least a stoichiometric equivalent between the anionic surfactant and the multivalent metal cation. For example, for each gram-ion of Mg++ there will be 2 gram moles of paraffin sulfonate, alkylbenzene sulfonate, etc., while for each gram-ion of Al3+ there will be 3 gram moles of anionic surfactant. Thus, the proportion of the multivalent salt generally will be selected so that one equivalent of compound will neutralize from 0.1 to 1.5 equivalents, preferably 0.6 to 1.4 equivalents, of the acid form of the anionic surfactant. At higher concentrations of anionic surfactant, the amount of the inorganic magnesium salt will be in range of 0 to 5 wt. %, more preferably 0.5 to 3 wt. %.
The liquid cleaning composition of this invention may, if desired, also contain other components either to provide additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example: Colors or dyes in amounts up to 0.5% by weight; preservatives or antioxidizing agents, such as formalin, 5-bromo-5-nitro-dioxan-1,3; 5-chloro-2-methyl-4-isothaliazolin-3-one, 2,6-di-tert.butyl-p-cresol, etc., in amounts up to 2% by weight; and pH adjusting agents, such as sulfuric acid or sodium hydroxide, as needed. Furthermore, if opaque compositions are desired, up to 4% by weight of an opacifier may be added.
In final form, the instant compositions exhibit stability at reduced and increased temperatures. More specifically, such compositions remain clear and stable in the range of 5xc2x0 C. to 50xc2x0 C., especially 10xc2x0 C. to 43xc2x0 C. Such compositions exhibit a pH of 2 to 4.0 which is achieved by the addition of caustic soda or alkanolamide. The liquid microemulsion compositions are readily pourable and exhibit a viscosity in the range of 6 to 400 milliPascal. second (mPas.) as measured at 25xc2x0 C. with a Brookfield RVT Viscometer using a #2 spindle rotating at 50 RPM.
The following examples illustrate liquid cleaning compositions of the described invention. Unless otherwise specified, all percentages are by weight. The exemplified compositions are illustrative only and do not limit the scope of the invention. Unless otherwise specified, the proportions in the examples and elsewhere in the specification are by weight.

Acidic all purpose liquid cleaning compositions


A releasable locking mechanism is provided that includes a carrier, at least one projection and an actuator. The projection extends from the carrier and is rotatable along a rotational axis between a locked state and an unlocked state. The actuator is operably coupled to the projection and is movable along a first axis between a first position and a second position whereby in the first position the projection is rotated to the locked state and in the second position the projection is rotated to the unlocked state, the first axis being substantially perpendicular with the rotational axis.

Locking mechanisms can be utilized to secure a variety of carriers within receptacles. For example, a carrier such as an electronic module can be inserted and secured within a base device, such as a computer. Oftentimes it is desirable to have the module secured, yet also be removable so that replacement and/or upgrade modules can be inserted into the base device. For example, in one form the module is a copper transceiver module and the base is a router for routing data packets. In this form it may be desirable to later upgrade the copper module with a fiber optic module without having to replace the entire router.
Oftentimes the carrier and receptacle are designed to be compact structures and therefore it may be desirable to have the locking mechanism also be compact to minimize overall space. For example, electronics are generally becoming more compact and therefore, locking structures must also be miniaturized.
Furthermore, it is often desirable to easily remove the carrier from the receptacle. However, the carrier should be secured such that accidental contact does not unlock and/or remove the carrier from the receptacle.
It is known to utilize an actuating member to retract biased projections back into the carrier such that the carrier can be removed from the receptacle. However, these devices can be complex. Furthermore, these devices oftentimes require additional force to retract the projections as they may get caught on the receptacle as they are retracted into the carrier.
In order to provide such features, the locking mechanism of the present invention is provided that overcomes the disadvantages of the prior art.


There is provided a composition for healing burns and wounds in mammals, which contains a cromolyn compound or the combination of a cromolyn compound and hyaluronic acid a corticosteroid.

1. Field of the Invention
This invention relates the treatment of decubitus ulcers, burns, open sores, incisions and wounds in mammals. In particular, it relates to topical wound therapeutic formulations containing a cromolyn compound alone or the combination of hyaluronic acid (hyaluronan) and a cromolyn compound. The formulations can also be used in combination with elements found in amniotic fluid.
2. Description of the Prior Art
Adult wound repair is characterized by fibrosis, scarring, and sometimes by contracture. The results of this deforming process affect every form of surgery and can have devastating consequences. In contrast fetal wound healing proceeds without such fibrosis or scar formation, Michael T. Longaker, M.D., Ernie S. Chiu, B.S., N. Scott Adzick, M.D., Michael Stern, D.D.S., Michael R. Harrison, M.D., and Robert Stern, M.D., Studies in Fetal Wound Healing, V. A Prolonged Presence of Hyaluronic Acid Characterizes Fetal Wound Fluid, Ann Surg, April 1991, pp. 292-296.
It is known that hyaluronic acid bonds with fibronectin and together they have a powerful effect on the body""s cellular matrix. It is also known that urea, produced by the fetus has an effect on cell migration. Elements such as glucose, protein, sodium, potassium, calcium, magnesium, phosphate and chloride that form the amniotic fluid, work together with an inseparable bond and synergy.
Fibronectin is important in wound healing. However, the presence of certain proteases in excess binds with the fibronectin and prevents its activity in healing.
Several prior art patents disclose therapeutic formulations including hyaluronic acid. Lindblad, xe2x80x9cHyaluronic Acid Preparation used for Treating Inflammations of Skeletal Jointsxe2x80x9d; U.S. Pat. No. 4,801,619 disclosed the use of hyaluronic for intra-articular administration for the treatment of steroid arthropathy and progressive cartilage degeneration caused by protoglycan degradation. Langerman, xe2x80x9cSpare Parts for Use in Ophthalmic Surgical Prodecures: U.S. Pat. No. 4,888,016 disclosed the use of hyaluronic acid in ophthalmic surgery as an artificial xe2x80x9cspare partxe2x80x9d for surgical implantation in the eye during an extracapsular cataract extraction. Alvarez, xe2x80x9cThree Step Wound Treatment Method and Dressing Thereforxe2x80x9d; U.S. Pat. No. 4,813,942, which is herein incorporated by reference, disclosed the use of hyaluronic acid in the third step of a three-step treatment. The invention calls for hyaluronic acid to be in a hydrocolloid dressing which will provide controlled delivery over a period of 24 to 96 hours to promote thickening of the epidermal cells, thus strengthening the wound. Balazs et al, xe2x80x9cCross-Linked Gels of Hyaluronic Acid and Products Containing Such Gelsxe2x80x9d; U.S. Pat. Nos. 4,582,865, 4,636,524 and 4,636,865 disclosed the use of cross-linked gels of hyaluronic acid as a drug delivery system.
None of these prior art references claim to use hyaluronic acid and a cromolyn compound in the treatment of burns, open sores, incisions, and wounds and there is no combination with calcium, phosphate, uric acid, urea, sodium, potassium, chloride, and magnesium to simulate amniotic fluid.
U.S. Pat. Nos. 5,190,917 and 5,290,762, which are herein incorporated by reference disclose the roles of serine protease inhibitors in treatment of inflammation.
U.S. Pat. No. 4,970,298 which is herein incorporated by reference discloses a biodegradable matrix which comprises collagen, hyaluronic acid and fibronectin which enhance healing of wounds. Collagen, which is oversecreted by the body in response to an injury or wound, is known to be responsible for scar formation. Georgalas et al., xe2x80x9cSkin Treatment Composition and Method for Treating Burned Skin,xe2x80x9d U. S. Pat. No. 4,839,019, discloses a composition, which counteracts moisture loss and promotes healing of burned or sunburned skin comprised of polyglycerylmethacrylate, glycerine, allantoin, panthenol, amino acid complex, and fibronectin.
The invention relates to formulations containing a cromolyn compound selected from the group consisting of cromolyn, cromolyn sodium, disodium cromolyn and esters thereof. There is also provided combinations of a cromolyn compound and hyaluronic acid. The mixture can be further combined with calcium, phosphate, uric acid, urea, sodium, potassium, chloride and magnesium, all elements found in amniotic fluid, to provide a unique synergy that is effective in the treatment of burns, open sores, incisions and wounds in mammals.
The invention is used for wound therapeutic formulations, for topical application, for treating decubitus ulcers, burns, traumatic damage caused by irradiation of the skin, the deleterious effects of open sores, incisions and wounds on skin and further provides a mixture which simulates the fetal in utero wound healing matrix in a safe and effective amount.
Hyaluronic acid or the cromolyn compound alone in a pharmaceutical base, are sufficient for treating minor injuries. The combination of a cromolyn compound and hyaluronic acid, speeds healing. Additional elements comprising a mixture of constituents selected from the group of calcium, phosphate, uric acid, urea, sodium, potassium, chloride and magnesium, which are found in amniotic fluid, promote healing in more serious injuries.
The cromolyn compounds are inhibitors of PAR-2 (proteinase activator receptor-2) and prevent the degranulation of mast cells so as to control the release of chymase and tryptase that may cause scarring.
A preferred topical composition for use in serious injuries such as burns comprises by weight of the mixture: 0.01% to 1.50% calcium; 0.01% to 0.10% phosphate; 0.01% to 2.00% uric acid, 0.01% to 2.00% urea; 0.02% to 1.50% sodium; 0.01% to 0.10% potassium; 0.01% to 0.70% chloride; 0.001% to 0.01% magnesium; 0.01% to 2.50% hyaluronic acid; and 1.0% to 5.00% of a cromolyn compound.
In the best mode, the hyaluronic acid comprises by weight about 0.10% to 2.50% of the mixture and the cromolyn compound about 1.0 to 5.0% in the mixture or alone.
The invention is a means for delivery of cromolyn alone or the combination of hyaluronic acid and a cromolyn compound in a topical preparation for the treatment of decubitus ulcers, burns, open sores, incisions and wounds for optimum healing.
In accordance with the invention, there is provided herein formulations useful for topical application comprising a cromolyn compound alone or in combination with hyaluronic acid and/or at least four members of the group consisting of calcium, phosphate, uric acid, urea, sodium, potassium, chloride, and magnesium, all elements healing matrix and a safe and effective amount of a topical carrier, in combinations described below.
Tissue repair in the mammalian fetus is fundamentally different from normal adult healing. In adult humans, injured tissue is repaired by collagen deposition, collagen remodeling and eventual scar formation, whereas fetal wound healing appears to be more of a regenerative process with minimal or no scar formation. The adult wound heals by the replacement of normal dermis with a scar that consists of excessive and abnormally organized collagen. In marked contrast, the fetal wound contains a persistent abundance of hyaluronic acid while collagen deposition is rapid and nonexcessive, Bruce A Mast, M.D., Robert F. Diegelmann, Ph.D., Healing in the Mammalian Fetus, Surg. Gyn. And Ob., Vol. 174, pp. 441-451, May 92.
What is known is that hyaluronic acid has a definite role in harnessing and manipulating the natural reparative capacity of tissue fibroblasts and the hyaluronic acid protein complexes play a significant role in vivo organization or scar tissue, D. A. R. Burd, R. M. Greco, S. Regaurer, M. T. Longaker, J. W. Siebert and H. G. Garg, Hyaluronan and Wound Healing: a New Perspective, Journal of Plastic Sutery, 1991, pp. 579-584.
Hyaluronic acid has played a very limited role in the care and treatment of burns, open sores, incisions and wounds because there has not been an effective delivery system that could deliver hyaluronic acid, which is found in abundance in amniotic fluid, to the wound site in a manner that replicated the moist environment and the other healing benefits discovered in amniotic fluid.
It is understood that the term hyaluronic acid includes its derivatives and broadly refers to naturally occurring, microbial and synthetic derivatives of acidic polysaccharides of various molecular weights constituted by residues of glucuronic acid and N-acetyl-D-glucosamine.
The cromolyn compounds, because of their control of degranulation of mast cells and being anti-PAR-2, permit proper laying down of tissue and can prevent keloid scars. The serine protease inhibitor is used in an amount of about 0.5 to 5% by weight of the composition.
The wound healing process is significantly different in adults as compared to the healing that takes place in amniotic fluid. Sharply increased levels of hyaluronic acid characterize adult wound healing during the first three days. By the seventh day, hyaluronic acid is not detectable.
Fetal wound healing is characterized by sharply increased levels of hyaluronic acid during the first three days, but unlike adult wound healing the level of hyaluronic acid remains elevated for 21 days. These findings are the result of research conducted by Michael T. Longaker, M.D., Ernie R. Harrison, M.D., and Robert Stern, M.D. and reported in an article titled Studies in Fetal Wound Healing: V. A. Prolonged Presence of Hyaluronic Acid Characterizes Fetal Wound Fluid, in Ann. Surg., April 1991, pp. 292-296.
The healing process of the fetus is controlled by high levels of hyaluronic acid and alpha 1-antitrypsin. In adult healing process there is an overproduction of elastase which leads to the formation of scar tissue. The topical addition of hyaluronic acid and a chymase and tryptase binding inhibitor in the wound bed will alter the adult healing process and facilitate accelerated healing and reduce the formation of scar tissue. The presence of the cromolyn compound protects fibronectin from being degraded by elastase and other proteases.
Cell growth stimulating compound, may be incorporated into the composition. According to the present invention, the human growth hormone is utilized in an effective amount of at least about 0.05 ng/ml. Most preferably, the cell growth stimulating compound includes a mixture of human growth hormone, insulin (containing transferrin or transferrin-free) and/or triiodothyronine or thyroxin, each compound in an amount ranging from at least about 0.05 ng/ml, preferably at least about 0.5 ng/ml, and more preferably at least 1 ng/ml or more. In the case of insulin, the effective amount of insulin generally ranges from about 5 ng/ml to about 100 ug/ml and more preferably about 50 ng/ml to about 2 ug/ml within this range.
In addition to effective amount of cellular growth stimulating hormone and cellular nutrient media, formulations according to the present invention may also contain hydrocortisone, which in certain instances may have a beneficial overall effect in enhancing wound healing.
Hydrocortisone is found to improve the cloning efficiency of fibroblasts, enhancing the maintenance of epidermal keratinocytes. The preferred amount to be incorporated is generally within the range of about 0.2 umol to about 50 umol. The formulations according to the present invention may also include an effective amount of an antimicrobial agent, for example, antibiotics and antifungal agents, such as griseofulvin and nystatin and antiviral agents and the like. The antimicrobial agent may be added for its ability to treat an infection, or alternatively, for its prophylactic effect in avoiding an infection. Cromolyn and hydrocortisone in the formulation are effective in treating and/or preventing decubitus ulcers.
There are many different carriers, which can affectively guide delivery to the skin. Such delivery system is desirable especially in dogs who have the tendency to lick their wounds. Therefore, a liposome which causes a rapid infusion into the skin is desirable. One such delivery system is found in xe2x80x9cNovasomexe2x80x9d a trademark for a carrier of Eavsco Corp. of New Jersey.
Otherwise, an occlusive bandage type of carrier such as vasoline or aquaphor can be used.

Abstract: Advantageously, elements found in amniotic fluid are also included.


The present invention refers to the production of a polyester-type polymer and more particularly to the solid phase condensation of a polyester. The invention presents a process for manufacturing polyester which comprises at least the following steps: a) esterifying of transesterifying a carboxylic diacid or a carboxylic acid diester with a diol, b) prepolymerizing the esterification or transesterification product in liquid phase until an average degree of polymerization between 10 and 50, preferably between 20 and 45, c) preparing a dispersion of the prepolymer in a non-solvent of diol and non-swelling of the prepolymer liquid, the prepolymer being present in the dispersion in the form of solid particles having diameters under 2 mm and crystallized, with a crystalline lamella thickness under 17 nm, d) polymerizing in dispersed solid phase, e) recovering solid particles. The accomplishment of a dispersed solid phase polymerization permits improving the reaction kinetics. To obtain this improvement, the dispersed solid phase polymerization must be effected with a prepolymer having a particular degree of polymerization properties, of solid particle sizes and of crystalline qualities of the solid.

The present invention refers to the production of a polyester-type polymer and particularly to the solid phase condensation of a polyester.
The main method to obtain polyester-type polymers consists in a high-temperature condensation either of the esterification product of a carboxylic diacid and a diol or the transesterification product of a diester and a diol. This condensation is effected in molten state. For the obtention of poly(ethylene terephthalate) (PET), the product of the transesterification of methyl terephthalate (DMT) and ethylene glycol (EG) or the esterification product of purified terephthalic acid (PTA) and ethylene glycol. The condensation is carried out until the obtention of a compound having the desired molecular weight. This condensation cannot lead to polymers having a very high viscosity index, specifically above 85 ml/g. Above such a viscosity, the type of technology presently employed does not permit the continuation of the reaction. If the obtention of a high molecular weight is desired, it is however necessary to carry out a solid state post-condensation at temperatures around 200xc2x0 C. This consists in heating a load of polymer granules. This solid state low temperature procedure permits especially the obtention of polymers at low degradation levels.
Du Pont de Nemours company, especially in U.S. Pat. No. 5,548,868 and U.S. Pat. No. 5,510,454 describes another method for obtaining polyesters. This method consists in producing prepolymer tablets presenting low degrees of polymerization, ranging between 2 and 40. The tablets are subsequently condensed to solid state according to the procedure previously described for post-condensation. It is possible through this method to obtain polymers of any molecular weight, having viscosity indexes under or over about 85 ml/g, according to the post-condensation operational conditions.
The previously described solid state condensation and post-condensation procedures present considerably low kinetics and constitute a limiting step in the manufacture of polyesters. Notwithstanding the progresses attained, constant efforts are being made in order to improve the performance of the solid phase condensation or post-condensation step.
The object of the present invention is to overcome the problems inherent to solid phase condensation by proposing a process which permits increasing the kinetics of solid phase condensations. It proposes an alternative to known processes through effecting a solid phase condensation dispersed in a liquid. This permits overcoming the difficulties encountered in the usual processes, increasing the condensation kinetics and hence attaining faster the desired degrees of polymerization. The accomplishment of the solid phase condensation in a liquid medium must be effected on a solid prepolymer having particular properties, necessary for the good conduction of the process and speeding up of the kinetics. The object of the invention however is also a process for obtaining the prepolymer in solid phase dispersed to be condensed, as well as the characteristics, particularly the crystalline characteristics which permit making it sufficiently reactive.
The invention presents a process for manufacturing polyester which comprises at least the steps described above. It may comprise other upstream, downstream or intermediate steps. The process steps may be effected continuously or discontinuously in separate devices, or in the same devices. The essential steps are the following:
a) esterifying or transesterifying a carboxylic diacid or a carboxylic acid diester with a diol,
b) prepolymerizing the esterification or transesterification product in liquid phase until an average degree of polymerization between 10 and 50, preferably between 20 and 45,
c) preparing a dispersion of the prepolymer in a non-solvent of diol and non-swelling of the prepolymer liquid, the prepolymer being present in the dispersion in the form of solid particles having diameters under 2 mm and crystallized, with a crystalline lamella thickness under 17 nm,
d) polymerizing in dispersed solid phase,
e) recovering solid particles.
The process may be applied to the polymerization of any carboxylic diacid with any diol. It may be particularly applied with the following diacids: terephthalic acid, isophthalic acid, naphthalenedioic acid, sulfo-5-isophthalic acid and mixtures thereof. It may be applied particularly with the following diols: ethylene glycol, butane diol, neopentyl glycol, diethylene glycol, bisphenols, 1-2 propane diol, cyclohexyldimethanol, and mixtures thereof.
The process may be applied particularly to the synthesis of poly(ethylene terephthalate), from terephthalic acid or methyl terephthalate and diethylene glycol monomers.
Esterification or transesterification step a) is a step commonly carried out in the polyester manufacturing industrial processes. Two routes for example are mainly employed to manufacture poly(ethylene terephthalate).
The first route of obtention is via said xe2x80x9cmethyl terephthalatexe2x80x9d (DMT). It comprises a transesterification reaction. Molten DMT is solubilized in ethylene glycol (EG) present in excess, the molar ratio EG/DMT being about 1.9 to 2.2, and the reaction is carried out under atmospheric pressure and at temperatures around 130xc2x0 C. to 250xc2x0 C. A catalyst such as for example manganese acetate must be present. The methanol during the reaction is eliminated through destilation. The ethylene glycol present in excess is eliminated by evaporation after the transesterification reaction. The catalyst which is also a degradation catalyst of the polyester is blocked with the aid of phosphorous compounds after the reaction. The product resulting from the transesterification is a blend of bis-hydroxyethyl-terephthalate (BHET) oligomers.
The second route is the route called xe2x80x9cdirect esterificationxe2x80x9d. It refers to an esterification reaction of terephthalic acid with ethylene glycol. It is carried out at temperatures between 130xc2x0 C. and 280xc2x0 C. Terephthalic acid, molten at such temperatures, is not soluble in the ethylene glycol but is so in the ester product of the reaction. However the solubilization of the reagent in the medium is progressive. The ethylene glycol is present in a molar ratio EG/terephthalic acid around 1 to 3. From this reaction results a mixture of oligomers having end functions in the form of terephthalic acid or of hydroxyethyl terephthalate.
The utilization of such processes are the object of several studies described in literature. The above-indicated conditions do not constitute a limitation to the scope of the present invention.
The subsequent solid phase prepolymerization and polymerization steps are condensation polymerization steps. They are generally catalyzed with the aid of metal compounds, for example antimony, titanium or germanium compounds. They may be catalyzed by any polycondensation catalyst of the prior art.
Liquid phase prepolymerization step b) may be accomplished preferably by two modes. The first mode for carrying out this step is to carry out the prepolymerization in molten phase. The second mode therefor consists in effecting the prepolymerization of the molten phase dispersed in a liquid medium. The way for accomplishing these two embodiments will be described subsequently. The prepolymer obtained presents an average degree of polymerization between 10 and 50, preferably between 20 and 45.
By xe2x80x9caverage degree of polymerizationxe2x80x9d it is to be understood the absolute average polymerization degree defined by the following formula:       DP    n    =                    1                  M          o                    *                                    ∑            i                                                        n              i                                                  M              i                                                            ∑            i                                          n            i                                =                  M        n                    M        o
where M0 is the molecular weight of the repetitive portion of the polymer, Mi is the molecular weight of the referenced chain length i, and ni is the number of referenced chain lengths. The molecular weights are absolute molecular weights.
The average degree of polymerization is related to the absolute number average molecular weight Mn, according to the formula above. The latter is is evaluated by Gel Permeation Chromatography (GPC) with viscosimetrical coupling.
The viscosity of the polymer in solution is associated with the length of the chains and hence the number average molecular weight and with the average degree of polymerization. It is an indicator of the advancement of the polymerization.
In the present document, viscosity index (VI) is to be understood as the viscosity in ml/g measured at 25xc2x0 C. with the aid of a Ubbelohde-type viscosimeter for a 0,005 g/ml solution of polymer dissolved at 115xc2x0 C. in a mixture composed of 50% by weight of phenol and 50% by weight of 1-2 dichlorobenzene. For PET, an interrelation between the viscosity index and the average degree of polymerization evaluated by GPC was established:
DPn=1.19*VIxe2x88x927,
wherein VI is in ml/g.
This interrelation is valid for viscosity indexes comprised between 10 and 70 ml/g.
Step c) consists in preparing a dispersion of the prepolymer obtained from step b). The dispersed prepolymer is in the form of dispersed particles. The dispersion liquid used must not be a solvent of the diol and must not be a swelling medium of the prepolymer. For the accomplishment of the subsequent polymerization in dispersed solid phase, the solid particles must have a diameter under about 2 mm, preferably 1 mm, and crystallized with crystalline lamellas about 17 nm thick, preferably under about 12 nm. The formation of the solid particle dispersion may be carried out according to several modes. The modes to form the dispersion depend particularly on the mode for carrying out the prepolymerization step. Two modes for forming the dispersion can be considered: a first mode for preparing the dispersion consists in solidifying the prepolymer in a particulate form and isolating it (first phase) and then placing the particles in the presence of the dispersion medium (second phase). A second mode for effecting the dispersion consists in effecting the two phases simultaneously, the solidification of the prepolymer occurring within the dispersion medium. These modes for accomplishment will be detailed subsequently.
Step d) of solid phase polymerization dispersed in a liquid medium permits obtaining high polymerization kinetics in that case where the solid particles of the prepolymer present the characteristics described above, and obtained through the procedures described for example in the present document.
The step of solid phase polymerization dispersed in a liquid medium must be effected in a medium which does not dissolve the diol to be reacted and neither swell the prepolymer. More particularly, for the manufacturing of poly(ethylene terephthalate), the medium must not be an ethylene glycol solvent. This characteristic is meant to permit the elimination of the diol and accelerate the polymerization reaction. As adequate liquids to carry out the invention, one can mention hydrocarbonated compounds. These compounds can be obtained for example from a fraction of aliphatic hydrocabons having a number of carbon atoms under or equal to 20. The hydrocarbon fraction may be a liquid product under atmospheric pressure and at the dispersed phase polymerization temperature. The dispersed solid phase condensation may also be advantageously be accomplished in a gaseous hydrocarbon fraction at atmospheric pressure at a temperature above 150xc2x0 C. and maintained in liquid state under pressure during the dispersed solid phase polymerization. Such a medium is eliminated by fractionation at the end of the process, in order to recover the polymer.
The elimination of the diol from the medium is facilitated through entrainment by a flow of inert gas. The gas may be advantageously introduced by bubbling in the dispersion medium. It may be selected from nitrogen, rare gases, inert gases such as for example nitrogen-enriched air, carbon dioxide, and mixtures thereof. The presence of the inert gas permits to further avoid any presence of oxygen within the medium and thus avoid the degradation of the polyester. The entrained dispersion medium may be recycled to the reaction medium after collection and separation of the diol.
In order to stabilize the dispersion of solid particles of the prepolymer to be condensed, it is possible, without this having to constitute a limitation of the described process, to add to the medium an agent. This stabilizing agent is advantageously a compound having surface-active properties comprising a polar portion and a non-polar portion and not comprising any function reactive in the medium. It may be chosen for example from protected poly(ethoxylated)alkyl-phenols, for example protected poly(ethoxylated)nonyl-phenol, and protected poly(ethoxylated)alkanes. The protection is obtained through alkoxylation, through a pentoxylation for the poly(ethoxylated)nonyl-phenols or through a methoxylation for the poly(ethoxylated)alkanes. As an example of a protected poly(ethoxylated)alkane one can mention a 11 to 12 times ethoxylated C14 alkane. The dispersed solid phase polymerization is carried out at temperatures at which the dispersed particles are in the solid state. The temperature may vary during the advancement of the reaction, generally increasing, but must always remain under the temperature which provokes the melting of the most fusible particles in the medium. The presence of particles in the molten state facilitates the particle aggregation phenomena and reduces the polymerization speed. For example the dispersed solid phase polymerization may be carried out at a temperature 10xc2x0 C. lower than the melting temperature of the dispersed polymer.
The dispersion is characterized in that the solid particles have a diameter lower than 2 mm. By diameter it is to be understood the average diameter of the dispersed particles. Preferably the diameter of the solid particles is lower than 1 mm.
The dispersed particles must present particular crystalline characteristics for the accomplishment of a dispersed solid phase condensation. The thickness of the crystalline lamellas of the particles must be lower than about 17 nm and preferably around 12 nm.
By crystalline lamellas thickness it should be understood the length measured by wide-angle difraction (WAXS) according to the following references:
N. S. Murphy and H. Minor, xe2x80x9cGeneral procedure for evaluating amorphous scattering scans crystallinity from X-ray diffraction scans of semicrystalline polymersxe2x80x9d, Poly, vol. 31, 996-1002 (1990).
This method consists in pinpointing the diffraction corresponding to the crystalline reflection on the Miller indexes plan (010) at a 2xcex2 angle of 17.8xc2x0. The average dimension ACS010 of the crystal is given by the Scherrer equation:
ACS010=k*l/(a*cosxcex2),
wherein k-0.9, l is the wave length of copper, a is the width at mid-height in radians of the peak of diffraction.
The formation of solid particles and their dispersion in the prepolymer non-solvent and non-swelling dispersion medium, simultaneously or subsequently, may depend on the mode for carrying out the prepolymerization step b). Two modes of carrying out the prepolymerization are adequate for realizing the invention.
The first prepolymerization mode is a prepolymerization in a molten phase dispersed in droplets in a liquid medium. It is accomplished placing a product such as that obtained through step a), molten, in contact with a heated liquid medium, to which a catalyst is eventually added. This medium must not be a solvent of the compounds involved. The medium may be exactly the same as that applied for the subsequent dispersed solid state polymerization. It may be different from that which shall be used subsequently. It may thus be constituted from the same types of components, hydrocarbons for example, be identically submitted to a gas flow, and contain one or more stabilizers. The addition of a stabilizer may permit furthermore a better control of the dispersion of the molten prepolymer and avoid the coalescence of the droplets. The use of an 11 to 12 times ethoxylated and methoxylation-protected C14 alkane gives particularly remarkable results. The characteristics of the media have been described in detail above. The reaction temperature must be controlled in order to maintain the compound to be polymerized in a molten state, for example above 220xc2x0 C. It may be increased during the reaction period, for example until about 260xc2x0 C. The prepolymerization is carried out until the obtention of an average degree of polymerization comprising between 10 and 50, preferably between 20 and 45. At this stage of the process, the prepolymerization product is dispersed in the molten state in a dispersion medium at a temperature above the melting temperature of the prepolymer. The second prepolymerization mode is a molten state prepolymerization. It is carried out by heating the product of the type obtained in step a), to which a catalyst is eventually added, the product being in the liquid state and constituting the mass of the medium. The molten phase prepolymerization may be carried out as follows: a mixture of the compound to be prepolymerized and the catalyst is heated until a temperature above the melting temperature of said compound, above 200xc2x0 C., preferably above about 260xc2x0 C. The reaction may be advantageously carried out under reduced pressure in order to favour the separation of ethylene glycol, and eventually water since the precursor employed in step a) is a carboxylic diacid. It may eventually be carried out with a sweep or bubble of inert gas. This facilitates the elimination of the ethylene glycol present in the medium. The prepolymerization is carried out until the obtention of an average degree of polymerization comprising between 10 and 50, preferably between 20 and 45. At this stage of the process the prepolymerization product is in a molten state isolated from any dispersion medium.
The prepolymerization product according to the mode of accomplishment in molten phase may be transformed into a state of crystallized solid particles and dispersed according to several modes. The crystallization is carried out at a temperature comprised within the range of crystallization temperatures of the prepolymer. This range lies within the following temperatures: glass transition temperature plus 25% of the difference between the melting and glass transition temperatures and melting temperature minus 25% of the same difference.
A first mode consists in rapidly solidifying the molten prepolymer and making it into solid particles with a diameter under 2 mm, preferably 1 mm, then placing the particles obtained in contact with the non-solvent of diol dispersion medium. The conformation may be effected for example by grinding or by cutting reed-shaped bodies having sections under 2 mm, preferably 1 mm. A second mode consists in spraying the prepolymerization product in a gaseous fluid at a temperature within the range of the crystallization temperatures of the prepolymer. The spraying must be effected in the form of droplets under 2 mm diameter, preferably 1 mm. The droplets solidified by contact with the gas are then put in contact with the non-solvent of diol and non-swelling of the prepolymer dispersion medium. A third mode of accomplishment consists in spraying the prepolymerization product in the non-solvent of diol and non-swelling of the prepolymer dispersion medium, said medium being at a temperature comprised within the range of the crystallization temperatures of the prepolymer. A fourth mode of accomplishment comprises a first phase which consists in spraying the prepolymerization product in the non-solvent of diol and non-swelling of the prepolymer dispersion medium, said medium being at a temperature above the melting temperature of the prepolymer. After this first phase, the prepolymerization product is dispersed in a molten state in a dispersion medium at a temperature above the melting temperature of the prepolymer.
Once the prepolymerization product is dispersed in the molten state in a dispersion medium at a temperature above the melting temperature of the prepolymer, proceeding it either from the first phase of the fourth dispersion mode after a molten phase prepolymerization, or from a molten phase prepolymerization dispersed in a liquid medium, the accomplishment of the dispersion may be effected mainly according to two modes of operation. According to a first mode of operation, the dispersion medium is rapidly cooled down to a temperature comprised within the range of the crystallization temperatures of the prepolymer. This cooling down may be effected for example by dilution with a cold liquid constituting the dispersion medium. The product obtained from this cooling is the suspension of solid particles in a non-solvent of diol non-swelling of the prepolymer liquid. A second mode of operation may applied if the liquid medium for dispersion of the molten phase is a gaseous product at a temperature above 150xc2x0 C. and maintained under pressure in the liquid state. This mode consists in submitting the medium to a temperature maintained in the range between the the crystallization temperatures of the prepolymer and to thus solidify the polymer initially molten in suspension. The particles are then placed in contact with the non-solvent of diol non-swelling of the prepolymer dispersion medium.
The connection within the same medium of the steps of dispersed molten phase prepolymerization, the effecting of the dispersion of the solid particles and the dispersed solid phase polymerization is a particularly simple and effective mode of accomplishment.
Step e) is a step during which the polymerization product in solid phase dispersed in a liquid medium is isolated from the dispersion medium. The isolation may be effected by any means which permits the separation of a liquid phase from a solid phase in suspension. The isolation may consist for example in a filtration, a decantation or an unstabilization of the dispersion. If the dispersion medium is a liquid medium constituted of a gaseous compound at atmospheric pressure liquefied under pressure, the isolation may be effected through retention of the medium.
The solid particles may be washed with any appropriate compound and then dried. As a washing compound one can mention for example heptane.
The solid particles can be used directly for applications, for instance for extrusion, or can be compacted into tablets or granules.


A conveying system for transporting wafers in clean rooms, the conveying system is configured as a transporting store and connects a plurality of processing centers for processing the wafers. Secondary conveying systems branch off from the conveying system and form supply buffers. In each case one secondary conveying system leads to at least one processing center from which a predetermined number of wafers can be removed, and fed to the processing center, optionally by use of at least one handling unit.

The invention relates to a conveying configuration for transporting wafers in clean rooms. The conveying configuration is a transporting store for the wafers and connects a plurality of processing centers for processing the wafers.
Such clean rooms form a constituent part of production facilities for semiconductor products. In particular, the wafers are processed in such production facilities, with the result that the wafers can be used for producing electronic components and the like.
During the processing of such wafers, the purity demands are high, which renders production under clean-room conditions necessary. The process for producing the wafers contains a multiplicity of different processing operations, for example various layer-growing processes, lithography and etching and diffusion processes.
High-outlay processing centers are necessary for each of these processes. During the production process, the wafers have to be fed to the individual processing centers.
In the case of known production installations, the wafers are transported between the individual processing centers by conveying systems defined, for example, as roller conveyors. The wafers are usually transported on the rollers of the roller conveyors in cassettes. A plurality of stockers are disposed on the roller conveyors, in each case a certain number of the stockers are disposed as closely as possible to a processing center. The stockers are stationary storage systems in which the wafer cassettes can be deposited and stored preferably under clean-room conditions. For this purpose, the cassettes with the wafers supplied by the conveying system are removed from the rollers of the conveying system and stored in the respective stocker. This process takes place automatically via handling systems, robots or the like. The capacity of the stockers is such that the respective processing center ensures a sufficient supply of wafers at all times.
In accordance with the requirements of a processing center, a number of cassettes with wafers are retrieved from the stocker, and fed to the processing center, at certain time intervals. In this case, the cassettes may be transported to the processing centers via vehicles that are driven by the operating staff. Alternatively, the transportation may take place via driverless, rail-borne or non-rail-borne vehicles. Transportation back into the stocker or directly back to the conveying system can take place in the same way.
The disadvantage here is that storing cassettes with wafers in the stockers is very costly. On the one hand, this results from the fact that the production costs of such stockers are very high. On the other hand, the stockers have a considerable overall size and, in addition, are required in large numbers. Therefore, a considerable surface area is required, and the clean rooms have to be of correspondingly large dimensions. Finally, the operations of the storage cassettes with the wafers in the stockers and retrieving them from the stockers involve a considerable amount of time since the cassettes have to be moved vertically for positioning purposes and, finally, have to be positioned at defined locations in the stocker. This processing outlay is not just considerably costly, but, such a discontinuous wafer-transporting system results in the overall production capacity being adversely effected.
A conveying system of the type mentioned in the introduction is known from U.S. Pat. No. 5,443,346. The conveying system serves for transporting wafers in a clean room. The conveying system contains an inter-bay conveying system via which the wafers are transported in the cassettes. Branching off from the inter-bay conveying system are intra-bay conveying systems via which the wafers are fed to individual processing stations and, following the processing, are transported away from the processing stations again. An intra-bay conveying system has a conveying rail on which a conveying unit is moved. The conveying unit contains, in particular, a positioning robot. The wafers are introduced into the individual processing stations by the positioning robot. The conveying unit carries along a small selection of wafers that are introduced into the respective processing stations. Since the quantity of wafers delivered in the cassettes via the inter-bay conveying system is larger than the number of wafers transported away via the intra-bay conveying system, there is provided, at the transition between the inter-bay conveying system and an intra-bay conveying system, an interface device in which the wafers are stored.
Published, Non-Prosecuted German Patent Application DE 40 17 006 A1 discloses a wafer-conveying system in which different clean rooms are connected to one another by a closed system of conveying channels. In this case, the conveying system may also be configured, in particular, as a transporting store. In the conveying channels, cassettes with wafers are transported onto transporting belts.
The wafers are transported in the conveying channels under clean-room conditions. For this purpose, filtered air flows through the individual conveying channels.
Provided at crossover points between the individual conveying channels are load locks for loading and unloading the cassettes with the wafers.
The loading and unloading operations at the load locks can be carried out manually by the operating staff. Alternatively, a handling unit may be provided for this purpose.
When a load lock is loaded with a cassette, the destination for the cassette is input via a keyboard.
In principle, an automated flow of the wafers may be realized using such a conveying system.
The disadvantage here, however, is that the cassettes have to be loaded into the conveying system individually one after the other, and also have to be removed therefrom individually, via the load locks. If a plurality of cassettes are supplied at one destination, it is therefore necessary to maintain the order in which the cassettes are to be processed further following removal. This limits the flexibility of the conveying system to a considerable extent.
It is also disadvantageous that the individual removal of the cassettes from the load locks is very time-consuming.
However, on account of the high productivity of the processing centers in semiconductor-production installations, it is necessary for a multiplicity of cassettes of wafers to be available at the processing center simultaneously at certain times.
Accordingly, such a conveying system can be only be used in conjunction with a stocker which is assigned to the respective processing center. The cassettes that have been removed individually from the load locks are then stored in the relevant stocker. Depending on requirements, a predetermined number of cassettes are then simultaneously removed and fed to the processing center.
Published, Non-Prosecuted German Patent Application DE 197 29 525 A1 relates to an apparatus for transporting disc-like substrates, for example digital video discs, from starting stations, via a plurality of process stations, to end stations, the process stations carrying out the processing operations, e.g. coating, monitoring, sorting and collection of the substrates. Gripper arms with grippers or suction devices allow the substrates to be transported further from station to station. There are provided a motor/gear unit with a pivoting device and two lifting devices which can be activated separately from one another and interact with gripper arms. The gear mechanism, which forms a conveying station, is disposed at the same distance away from a plurality of stations, for example the supply station, the coating stations, the return station and the checking station. The two lifting devices of the motor/gear unit simultaneously execute, by way of their gripper arms, identical and/or different lifting movements (vertical movements) and pivoting movements that take place at the same time as the latter or following the latter.
Published, Japanese Patent Application JP 08268512 A discloses a storage device for substrates. The storage device has a rack, it being possible for the substrates to be stored on the rack, and retrieved therefrom, by a loading and unloading unit. The substrates are stored intermediately on a loading bed for sorting purposes.
Published, Japanese Patent Application JP 09235010 A describes the construction of a roller conveyor.
Published, Japanese Patent Application JP 10035883 A discloses a transfer unit via which semiconductor products can be positioned reliably and precisely. In this case, a displaceable receiving device feeds the substrates to predetermined containers. The movement is controlled by a camera system.
European Patent Application EP 0 908 931 A2 discloses as prior art, not published before the priority date of the instant application, a conveying apparatus by which semiconductor products can be fed to different processing stations under clean-room conditions. The conveying apparatus contains a cassette in which the semiconductor products are transported under clean-room conditions. The cassette is transported on rails that likewise form a constituent part of the conveying apparatus. The cassette is introduced, via introduction openings, into the respective processing stations in which the semiconductor products are processed.
It is accordingly an object of the invention to provide a conveying system that overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which it is ensured that the wafers can flow, as far as possible, continuously.
With the foregoing and other objects in view there is provided, in accordance with the invention, in combination with a clean room having a plurality of processing centers for processing wafers, a conveying configuration for transporting the wafers to and in the clean room, the conveying configuration including:
a main conveying system functioning as a transporting store for the wafers; and
a plurality of secondary conveying systems branching off from the main conveying system, each of the plurality of secondary conveying systems leading, at a minimum, to one processing center and forms a supply buffer from which a predetermined number of the wafers can be removed and fed to the processing center.
The conveying system according to the invention, which is configured as a transporting store and is intended for transporting wafers, connects a plurality of processing centers for processing the wafers. Secondary conveying systems branch off from the conveying system. In each case one secondary conveying system leads to a certain processing center and forms a supply buffer. From the secondary conveying system, a predetermined number of wafers can optionally be removed, and fed to the processing center, by use of a handling unit.
The conveying system according to the invention ensures that the wafers flow continuously. A considerable advantage resides here in the fact that no stockers are required for storing the wafers.
By virtue of suitable dimensioning of the conveying system, the wafers are stored on the conveying system itself. From the conveying system, the number of wafers that is required in each case is guided directly to the processing center via the respective secondary conveying system. It is particularly advantageous here for the secondary conveying system itself to act as the supply buffer. This is achieved by suitable dimensioning of the secondary conveying system.
In this case, the individual wafers on the secondary conveying system are simultaneously accessible to the handling unit. For example, the secondary conveying system has a predetermined number of roller conveyors, on the top sides of which the wafers in the cassettes rest one behind the other. The handling unit then picks up, at defined receiving locations in each case, the required cassette and feeds it to the processing center. The freely selectable access of the handling unit on the secondary conveying system to the cassettes holding the wafers provides a flexible system for reacting to different wafer demands, in particular, to wafer load peaks.
A further advantage of the conveying system according to the invention is that it is of modular construction and can easily be adapted to changing production outputs.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a conveying system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.