A process of washing textiles is presented involving the delayed release of ingredients from a detergent composition. The process involves first dissolving the detergent in water resulting in a pH below 8, slowly dissolving the coating on a coated alkalizing agent to raise the pH to above 8.5, and dissolving the polymeric acid coating on a detergent ingredient, due to the pH above 8.5, to release the ingredient into the wash water.

This invention relates to coated solid detergent components and to detergent compositions containing these coated components. More particularly, the invention relates to detergent compositions which release one or more of their ingredients to the wash liquor with delay and under control, the release of these ingredients being controlled through the pH value of the wash liquor.
The controlled release of individual detergent components at certain stages of the washing process is both economically and ecologically advantageous and, accordingly, is the subject of intensive research. Whereas, in principle, each individual detergent component can be released at a certain time through suitable physical and/or chemical measures, this controlled release is of paramount importance above all with regard to the interplay between bleaching and enzymatic cleaning. Accordingly, most publications are concerned with solving the problem of separating bleaching and enzymatic cleaning from one another as a function of time because the aggressive bleaching agents deactivate or even destroy enzymes. In principle, there are two ways of achieving this, namely: delayed release of the bleaching agents so that enzymatic cleaning is over before the bleaching agents are released in to the wash liquor and delayed release of the enzymes when the bleaching process is almost at an end. Since the bleaching agents destroy excess enzyme and thus prevent it from remaining on the laundry (odor formation), the first alternative is generally adopted. Another advantage of coating particles of bleaching agent lies in the increased stability in storage because uncoated bleaching agents are rapidly hydrolyzed in the event of prolonged storage, especially in moist air, with the result that the detergent compositions lose washing power.
Numerous ways and means are available for coating detergent ingredients. Various factors, such as the temperature or the hydrolysis of the coating material, may be utilized for the release process, depending on the particular solution adopted. Melt coating, in which the shell or coating only becomes permeable beyond a certain temperature, is difficult to achieve on account of the low washing temperatures preferred today because problems, such as lump formation, occur at low softening temperatures. Coating materials which hydrolyze under the effect of moisture also have disadvantages in regard to the stability in storage of the composition. Accordingly, there is a need to find a coating material which, on the one hand, would dissolve quickly without affecting the washing process providing certain conditions are maintained in the wash liquor and which, on the other hand, would be so stable that storage would not present any problems.
Detergent and bleaching compositions which contain a hydrogen peroxide source and a peroxy acid bleach precursor (bleach activator) and which produce an initial pH value in the alkaline range (pH 10-11) in the wash liquor and the delayed release of acid into the wash liquor to achieve a reduced pH value therein are described in the prior art literature, cf. for example European patent applications EP-A-0 290 081 (Unilever) and EP-A-0 396 287 (Clorox).
The delayed release of individual components in bleach-containing detergent compositions is mentioned in a number of patents. International patent applications WO 95/28454 (Procter and Gamble) and the series from WO 95/28464 to WO 95/284469 (all Procter and Gamble) and WO 95/28473 (Procter and Gamble) disclose bleach-containing compositions which contain a hydrogen peroxide precursor and a peroxy acid precursor, the release of the peroxy acid being controlled so that 50% of the peroxy acid concentration (so-called T50 Test) is reached within 180 to 480 seconds. The controlled release of the ingredients is achieved by coating individual ingredients, defined particle sizes, compacting and mechanical or manual addition. The particular ingredients coated vary from one application to another. Thus, in WO 95/28464, the release of the peracid is delayed in relation to the release of a complexing agent; in WO 95/28465 the release of the peracid is delayed in relation to the release of a builder and, in WO 95/28467, an enzyme is released before the peracid. WO 95/28466 describes the delayed release of an enzyme in relation to the release of a surfactant while WO 95/28468 and WO 95/28469 describe detergent compositions in which the release of an enzyme is delayed in relation to the release of a complexing agent for heavy metal ions or in relation to the release of a water-soluble builder. The systematic controlled release of individual components by controlling the pH value is not mentioned in any patent application of this series.
The coating of bleaching agents or bleach activators is also known from the prior art. U.S. Pat. No. 5,000,869 (Safe Aid Products) describes detergent compositions containing a coated halogenated glycol uril compound which is released through pH control. In this detergent composition, the bleaching agent is coated with a polymer which dissolves at a pH value above 6 and preferably at a pH value of 7.2 to 11.
WO 94/15010 (Procter and Gamble) discloses the coating of TAED with water-soluble acidic polymers, the coating being applied in the form of a melt, by spraying or in the form of solutions and dispersions, and also describes the simultaneous use of percarbonate which, in a preferred embodiment, is also coated. The acidic polymer has a solubility of at least 5 g/l at 20xc2x0 C.
EP-A-0 651 053 (Procter and Gamble) describes detergent compositions which contain an alkali metal percarbonate coated with alkali metal sulfate and carbonate, a bleach activator and a (coated) acidifying agent to be released with delay, so that the pH value of the wash liquor (1% solution at 20xc2x0 C.) is initially 9.5 to 13, falling to pH 7 to 9.3 after the acidifying agent has been completely released. The time required for complete release of the acidifying agent is between 30 seconds and 10 minutes. It is only when the pH value falls below a certain threshold that the coating of the bicarbonate is attacked and dissolved so that the bleaching effect is developed.
Coated bleaching agents which are only released into the wash liquor at an increasing pH value are not described in the prior art.
Now, the problem addressed by the present invention was to develop a system which would enable detergent ingredients, more especially bleaching agents, to be released through pH control and which would allow the release of those ingredients to take place in alkaline medium.
Accordingly, the present invention relates to a washing process for washing textiles using a solid particulate detergent composition, the pH value of the wash liquor being below 8 after the detergent has dissolved and rising to values above pH 8.5 through the dissolution of a coated alkalizing agent as the washing process progresses, the pH values above 8.5 enabling a specially coated ingredient to be released and allowing that ingredient to develop its effect with delay.
In one particular embodiment of the invention, a bleaching agent, preferably sodium percarbonate, is used as the alkalizing agent while a bleach activator, preferably tetraacetyl ethylenediamine (TAED), is used as the specially coated ingredient.
The present invention also relates to a solid particulate detergent composition containing
a) 1 to 40% by weight of a coated bleaching agent,
b) 0.5 to 15% by weight of a bleach activator,
c) 0.1 to 40% by weight of an acidifying agent, characterized in that the bleaching agent is coated with a shell-forming material which dissolves slowly in water irrespective of the pH value, the bleach activator is coated with a polymeric acid and the acidifying agent is used without any coating.
Through the presence of the acidifying agent, the pH value in the wash liquor is comparatively low, i.e. below 8, when the detergent composition is added. Thereafter the coating of the bleaching agent dissolves slowly and increasingly releases alkaline bleaching agent so that the pH value of the wash liquor increases. When the pH value of the liquor exceeds a value of about 8.5, the coating of the bleach activator begins to dissolve and releases the bleach activator. The full bleaching effect then begins to develop in the wash liquor with a certain delay. The time required for the bleaching effect to begin may be determined on the one hand through the quantity of acidifying agent added and, on the other hand, through the thickness and permeability of the coatings on the bleaching agent and the bleach activator. Depending on the formulation and the washing conditions, time intervals of 1 to 20 minutes are possible, for example for enzymatic cleaning to take place without most of the bleaching agent being present. The detergent composition shows excellent stability in storage through the coating of both the bleaching agent and the bleach activator and does not lose any of its bleaching activity, even in moist air.
Sodium perborate tetrahydrate and sodium perborate monohydrate are particularly important as coated bleaching agents which yield H2O2 in water (component a). Other suitable bleaching agents are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhydrates and H2O2-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecanedioic acid. The content of coated bleaching agents in the detergent is from 1 to 40% by weight and more particularly from 10 to 20% by weight, perborate monohydrate or percarbonate advantageously being used.
Suitable shell-forming materials for coating the particles of bleaching agent are water-soluble materials which dissolve slowly in the wash liquor, i.e. do not lead to any sudden release of the coated bleaching agent, and of which the dissolving properties are not too pH-dependent. Other preferred coating materials are those which, on dissolving, do not affect the pH value of the wash liquor. Preferred coating materials are fatty alcohols which may optionally be used in admixture with other coating materials. A mixture of fatty alcohols and aluminium stearate is mentioned purely by way of example. Other coating materials which have already been used for coating particles of bleaching agent are summarized in the following: magnesium sulfate and sodium hexaphosphate (BE 857 017, Solvay Interox), dihydrogen phosphate or pyrophosphates (EP 024 201, Clorox), phosphonic acids (EP 295 384, Degussa), sodium metaborate and silicate (DE 28 10 379, Degussa), waterglass and sodium polyphosphate (DE 27 12 138, Degussa), sodium sulfate, sodium carbonate and silicate (DE 26 22 610, Solvay Interox) or sodium bicarbonate (DE 24 17 572, Solvay Interox), borax and magnesium sulfate (DE 33 21 082, Kao), boric acid (DE 28 00 916, Solvay Interox) and also partly organic components, such as fatty derivatives, paraffins and waxes (EP 030 759, Solvay Interox, melting temperature of the compounds between 25 and 90xc2x0 C.), polyethylene glycols and fatty acid esters thereof with a molecular weight of 300 to 1,700 (DE 23 37 338, Solvay Interox), combinations with magnesium oxide (U.S. Pat. No. 4,131,879, Gretay AG and U.S. Pat. Nos. 4,120,812 and 4,131,462, both FMC Corp.), vinyl chloride/ethylene copolymer emulsions (DE 24 02 393, Solvay Interox) or vinyl chloride/ethylenelmethacrylate copolymer emulsions (DE 24 02 392, Solvay Interox).
The coating materials may be applied from the melt or from solutions or dispersions, the solvent or emulsifier being removed by evaporation. They may also be applied as a fine powder, for example by electrostatic techniques, although this method does lead to uneven and poorly adhering coatings. The coating materials may be applied to the particles of bleaching agent in stirred mixer/granulators. However, they are preferably applied in a fluidized bed, in which case the particles may simultaneously be graded. Should the coating materials lead to tacky products under certain conditions, it may be advisable additionally to xe2x80x9cpowderxe2x80x9d the coated particles of bleaching agent with fine-particle materials. Suitable powdering or dusting agents are any fine-particle materials, including other detergent ingredients, such as builders. Preferred additional powdering agents are zeolites, silicates, polymeric polycarboxylates, carbonate, citrates, starch, etc. The acidifying agent may also be partly used for powdering.
Suitable coated bleach activators (component b) are compounds which form aliphatic peroxocarboxylic acids preferably containing 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions. Substances which bear O- and/or N-acyl groups with the number of carbon atoms mentioned and/or optionally substituted benzoyl groups are suitable. Preferred bleach activators are polyacylated alkylenediamines, more especially tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycol urils, more particularly tetraacetyl glycol uril (TAGU), N-acyl imides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more especially n-nonanoyl or isononanoyl-oxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more especially phthalic anhydride, acylated polyhydric alcohols, more especially triacetin, ethylene glycol diacetate, 2,5-diacetoxy-2,5-dihydrofuran and acetylated sorbitol and mannitol and the mixtures thereof (SORMAN) described in European patent application EP 0 525 239 (Ausimont SPA), acylated sugar derivatives, more especially pentaacetyl glucose (PAG), pentaacetyl fructose, tetraacetyl xylose and octaacetyl lactose, and acetylated, optionally N-alkylated glucamine and gluconolactone and/or N-acylated lactams, for example N-benzoyl caprolactam, which are known from International patent applications WO 94/27970, WO 94/28102, WO 94/28103, WO 95/00626 (all Procter and Gamble), WO 95/14759 (Warwick) and WO 95/17498 (Procter and Gamble). The acyl lactams described in International patent application WO 95/14075 (Degussa) are also preferably used. The combinations of conventional bleach activators known from German patent application DE 44 43 177 (Henkel) may also be used. Coated bleach activators such as these are present in quantities of 0.5% by weight to 15% by weight, based on the detergent as a whole.
The coating of the bleach activator is carried out with polymeric acids which only dissolve at pH values above 8. At pH values below 8, the coated bleach activator particles can be stirred for hours in aqueous solution without dissolving. Polymeric acids particularly suitable for coating are, for example, polyacrylates which are distinguished on the one hand by the required pH-dependent solubility and, on the other hand, by favorable processing properties. Other polymeric acids which may be used as coating materials are copolymers of an unsaturated polycarboxylic acid, such as maleic acid, citraconic acid, itaconic acid and mesaconic acid, with an unsaturated monocarboxylic acid, such as acrylic acid or xcex1-alkyl-substituted acrylic acids.
The bleach activators may be coated in basically the same way as the bleaching agents. A process in which the polymeric acids are applied to the bleach activators via a dispersion is preferred.
The coating materials both for the bleaching agent and for the bleach activator are used in quantities which ensure optimum coordination of the individual components and hence precise controlled release. The quantity of coating material used will be gauged according to the time interval in which no release is to take place and according to the size of the coated particles. Preferred embodiments use less than 20% by weight of coating material, based on the weight of the coated particles, quantities of less than 10% by weight of the coating materials being particularly preferred.
The acidifying agent used as the third component is used in quantities of 0.1 to 40% by weight and preferably in quantities of 1 to 25% by weight, based on the final detergent. Any water-soluble substances capable of reducing the pH value of an aqueous solution to below 8 may be used as the acidifying agent. In cooperation with the other components of the detergents according to the invention, it is possible in this way to reach a starting pH value which is slowly increased as the washing process progresses (release of the bleaching agent), ultimately leading to release of the bleach activator and hence to the onset of the bleaching effect at pH values in the wash liquor above 8.5.
Preferred acidifying agents are inorganic and organic acids, for example solid mono-, oligo- and polycarboxylic acids, such as citric acid, tartaric acid and succinic acid, polycarboxylic acids, such as polyacrylic acid, and also such acids as malonic acid, adipic acid, maleic acid, fumaric acid, oxalic acid, boric acid or amidosulfonic acid and mixtures of the acids mentioned. Acidic salts, such as hydrogen sulfates or carbonates, may also be used as acidifying agents, in which case the only important requirement again is to ensure that the pH conditions are maintained. In order to obtain a wash liquor with a pH value below 8 as quickly as possible after the detergent according to the invention has dissolved, the acidifying agents should be selected for their ability to dissolve quickly and to adjust the pH value rapidly to the required levels. Any coating which would delay the dissolving process is unsuitable for the acidifying agents used for the purposes of the present invention.
From the applicational point of view, the acidifying agent(s) are required to be non-volatile. From this standpoint, solid acidifying agents which combine a minimal tendency to sublimate and a high melting point with high solubility in water are clearly preferred. Liquid or paste-form acidifying agents can only be used in small quantities below 5% by weight, based on the composition as a whole, and, if used, should be made up in such a way as to guarantee stability in storage, even at high air humidity levels. For this reason, liquid and readily volatile acids and acids which cannot be handled in powder-form detergents, such as hydrochloric acid, nitric acid or sulfuric acid, are automatically ruled out. In selecting the acidifying agent(s), it is of course important to bear in mind that the resulting wash liquor should damage neither the washing nor human skin.
Besides the coated components and uncoated auxiliaries which provide for the pH-controlled release of the coated ingredients, the detergents according to the invention contain other typical detergent ingredients, more especially anionic and nonionic surfactants, builders and other auxiliaries, such as soil repellents, foam inhibitors, salts of polyphosphonic acids, optical brighteners, enzymes, enzyme stabilizers, small quantities of neutral filler salts and dyes and perfumes, opacifying or pearlescing agents.
Suitable anionic surfactants are, for example, those of the sulfonate and sulfate type. Suitable surfactants of the sulfonate type are preferably olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C12-18 monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C12-18 alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of xcex1-sulfofatty acids (ester sulfonates), for example the xcex1-sulfonated methyl esters of hydrogenated coconut oil, palm kernel oil or tallow fatty acids, are also suitable.
Other suitable anionic surfactants are sulfonated fatty acid glycerol esters. Fatty acid glycerol esters in the context of the present invention are the monoesters, diesters and triesters and mixtures thereof which are obtained where production is carried out by esterification of a monoglycerol with 1 to 3 moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Suitable surfactants of the sulfate type are the sulfuric acid mono-esters of primary alcohols of natural and synthetic origin. Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C12-18 fatty alcohols, for example cocofatty alcohol, tallow fatty alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or C10-20 oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C16-18 alk(en)yl sulfates are particularly preferred from the point of view of washing technology. It can also be of particular advantage, especially for machine detergents, to use C16-18 alk(en)yl sulfates in combination with relatively low-melting anionic surfactants and, in particular, with anionic surfactants which have a lower Krafft point and which have a lower tendency to crystallize at relatively low washing temperatures, for example from room temperature to 40xc2x0 C. In one preferred embodiment of the invention, therefore, the detergents contain mixtures of short-chain and long-chain fatty alkyl sulfates, preferably C12-18 fatty alkyl sulfates or mixtures of C12-14 fatty alkyl sulfates or C12-18 fatty alkyl sulfates with C16-18 fatty alkyl sulfates and, more particularly, C12-16 fatty alkyl sulfates with C16-18 fatty alkyl sulfates. However, another preferred embodiment of the invention is characterized by the use not only of saturated alkyl sulfates, but also of unsaturated alkenyl sulfates with an alkenyl chain length of preferably C16 to C22. In this embodiment, mixtures of saturated sulfonated fatty alcohols consisting predominantly of C16 and unsaturated, sulfonated fatty alcohols consisting predominantly of C18, for example those derived from solid or liquid fatty alcohol mixtures of the HD-Ocenol(copyright) type (a product of Henkel KGaA), are particularly preferred. Ratios by weight of alkyl sulfates to alkenyl sulfates of 10:1 to 1:2 are preferred, ratios by weight of about 5:1 to 1:1 being particularly preferred. Other suitable anionic surfactants are 2,3-alkyl sulfates which may be produced, for example, by addition of sulfuric acid onto xcex1-olefins.
The sulfuric acid monoesters of linear or branched C7-21 alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched C9-11 alcohols containing on average 3.5 moles of ethylene oxide (EO) or C12-18 fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are only used in relatively small quantities, for example in quantities of 1 to 5% by weight, in detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent the monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain C8-18 fatty alcohol radicals or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol radical derived from ethoxylated fatty alcohols which, regarded in isolation, represent nonionic surfactants (for a description, see below). Of these, sulfosuccinates of which the fatty alcohol radicals are derived from ethoxylated fatty alcohols with a narrow homolog distribution are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut oil, palm kernel oil or tallow fatty acids. Particularly preferred soap mixtures are those of which 50 to 100% by weight consists of saturated C12-24 fatty acid soaps and 0 to 50% by weight of oleic acid soap.
The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.
Besides anionic surfactants, nonionic, cationic, zwitterionic or amphoteric surfactants may also be used in the detergent compositions. Nonionic surfactants are particularly preferred.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more particularly primary alcohols preferably containing 8 to 18 carbon atoms and an average of 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical may be linear or, preferably, 2-methyl-branched or may contain linear and methyl-branched radicals in the form of the mixtures typically present in oxoalcohol radicals. However, alcohol ethoxylates containing linear radicals of alcohols of native origin with 12 to 18 carbon atoms, for example coconut oil fatty alcohol, palm oil fatty alcohol, tallow fatty alcohol or oleyl alcohol, and an average of 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C12-14 alcohols containing 3 EO or 4 EO, C9-11 alcohol containing 7 EO, C13-15 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C12-18 alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C12-14 alcohol containing 3 EO and C12-18 alcohol containing 5 EO. The degrees of ethoxylation mentioned are statistical mean values which, for a special product, may be either a whole number or a broken number. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing more than 12 EO may also be used. Examples of such fatty alcohols are tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
In addition, alkyl glycosides corresponding to the general formula RO(G)x may be used as further nonionic surfactants. In this general formula, R is a primary, linear or methyl-branched, more particularly 2-methyl-branched, aliphatic radical containing 8 to 22 and preferably 12 to 18 carbon atoms and G is a glycose unit containing 5 or 6 carbon atoms, preferably glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is a number of 1 to 10 and preferably a number of 1.2 to 1.4.
Another class of preferred nonionic surfactants which are used either as sole nonionic surfactant or in combination with other nonionic surfactants are alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon atoms in the alkyl chain, more particularly the fatty acid methyl esters which are described, for example, in Japanese patent application JP 58/217598 or which are preferably produced by the process described in International patent application WO-A-90/13533 (Henkel).
Nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethyl amine oxide, and the fatty acid alkanolamide type are also suitable. The quantity in which these nonionic surfactants are used is preferably no more, in particular no more than half, the quantity of ethoxylated fatty alcohols used.
Other suitable surfactants are polyhydroxyfatty acid amides corresponding to formula (I):
in which RCO is an aliphatic acyl radical containing 6 to 22 carbon atoms, R1 is hydrogen, an alkyl or hydroxyalkyl radical containing I to 4 carbon atoms and [Z] is a linear or branched polyhydroxyalkyl radical containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which normally may be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (II):
in which R is a linear or branched alkyl or alkenyl group containing 7 to 12 carbon atoms, R1 is a linear, branched or cyclic alkyl group or an aryl group containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or a hydroxyalkyl group containing 1 to 8 carbon atoms, C1-4 alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxyalkyl group, of which the alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives of such a group.
[Z] is preferably obtained by reductive amination of a reduced sugar, for example glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst, for example in accordance with the teaching of International patent application WO-A-95/07331 (Procter and Gamble).
Besides the surfactant components, the detergent granules may also contain builders and other ingredients of detergents.
In addition to silicates, other builders and cobuilders may also be used as builders in the detergent compositions. These include, above all, zeolites, citrates and polymeric polycarboxylates.
Suitable crystalline layer-form sodium silicates correspond to the general formula Na2MSixO2x+1.yH2O, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4. Crystalline layer silicates such as these are described, for example, in European patent application EP-A0 164 514. Preferred crystalline layer silicates corresponding to the above formula are those in which M is sodium and x has a value of 2 or 3. Preferred crystalline layer silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both xcex2- and xcex4-sodium disilicates Na2Si2O5.yH2O are particularly preferred, xcex2-sodium disilicate being obtainable, for example, by the process described in International patent application WO-A-91/08171 (Henkel).
Other suitable builders are amorphous sodium silicates with a modulus (Na2O:SiO2 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties. The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying. In the context of the invention, the term xe2x80x9camorphousxe2x80x9d is also understood to encompass xe2x80x9cX-ray amorphousxe2x80x9d. In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. Particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described in German patent application DE-A44 00 024 (Henkel) Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably zeolite A and/or P. Zeolite MAP(copyright) (a commercial product of Crosfield) is particularly preferred as the zeolite P. However, zeolite X and mixtures of A, X and/or P are also suitable. The zeolite may be used in the form of a spray-dried powder or even as an undried stabilized suspension still moist from its production. Where the zeolite is used in the form of a suspension, the suspension may contain small additions of nonionic surfactants as stabilizers, for example 1 to 3% by weight, based on zeolite, of ethoxylated C12-18 fatty alcohols containing 2 to 5 ethylene oxide groups, C12-14 fatty alcohols containing 4 to 5 ethylene oxide groups or ethoxylated isotridecanols. Suitable zeolites have an average particle size of less than 10 xcexcm (volume distribution as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and, more preferably, 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing this is not ecologically problematical. Suitable phosphate builders are, in particular, the sodium salts of the orthophosphates, pyrophosphates and, in particular, the tripolyphosphates. Their content is generally not more than 25% by weight and preferably not more than 20% by weight, based on the final detergent. In some cases, it has been found that tripolyphosphates in particular lead to a synergistic improvement in multiple wash cycle performance in combination with other builders, even in small quantities of up to at most 10% by weight, based on the final detergent.
Other suitable organic builders are dextrins, for example oligomers and polymers of carbohydrates which may be obtained by partial hydrolysis of starches. The hydrolysis may be carried out by standard methods, for example acid- or enzyme-catalyzed methods. The end products are preferably hydrolysis products with average molecular weights of 400 to 500,000. A polysaccharide with a dextrose equivalent (DE) of 0.5 to 40 and, more particularly, 2 to 30 is preferred, the DE being an accepted measure of the reducing effect of a polysaccharide by comparison with dextrose which has a DE of 100. Both maltodextrins with a DE of 3 to 20 and dry glucose sirups with a DE of 20 to 37 and also so-called yellow dextrins and white dextrins with relatively high molecular weights of 2,000 to 30,000 may be used. A preferred dextrin is described in British patent application 94 19 091 (Cerestar). The oxidized derivatives of such dextrins are their reaction products with oxidizing agents which are capable of oxidizing at least one alcohol function of the saccharide ring to the carboxylic acid function. Dextrins thus oxidized and processes for their production are known, for example, from European patent applications EP-A-0 232 202 (Roquette Freres), EP-A-0 427 349 (Naturwissen-schaftliches Institut NL), EP-A-0 472 042 (Fertec Ferruzzi) and EP-A-0 542 496 (Procter and Gamble) and from International patent applications WO-A-92/18542 (Novamont), WO-A-93/08251 (Henkel), WO-A-94/28030 (Henkel), WO-A-95/07303 (Naturwissen-schaftliches Institut NL), WO-A-95/12619 (Agrartechnisches Institut NL)and WO-A-95/20608 (Henkel). A product oxidized at C6 of the saccharide ring can be particularly advantageous.
Other suitable co-builders are oxydisuccinates and other derivatives of disuccinates, preferably ethylenediamine disuccinate. The glycerol disuccinates and glycerol trisuccinates described, for example, in U.S. Pat. Nos. 4,524,009 and 4,639,325 (both Staley), in European patent application EP-A0 150 930 (Staley) and in Japanese patent application JP 93/339896 are also particularly preferred in this regard. Suitable quantities for zeolite-containing and/or silicate-containing formulations are between 3 and 15% by weight.
Other useful organic co-builders are, for example, acetylated hydroxycarboxylic acids and salts thereof which may even be present in lactone form and which contain at least 4 carbon atoms, at least one hydroxy group and at most two acid groups. Co-builders such as these are described, for example, in International patent application WO-A-95/20029 (Henkel).
Besides the surfactants, bleaching agents and builders, many other compounds may be used in detergents, including for example foam inhibitors, phosphonates, enzymes and optical brighteners.
It can be of advantage to add typical foam inhibitors to the detergents where they are used for machine washing. Suitable foam inhibitors are, for example, soaps of natural or synthetic origin with a high percentage content of C18 24 fatty acids. Suitable non-surface-active foam inhibitors are, for example, organopolysiloxanes and mixtures thereof with microfine, optionally silanized silica and also paraffins, waxes, microcrystalline waxes and mixtures thereof with silanized silica or bis-stearyl ethylenediamide. Mixtures of various foam inhibitors, for example mixtures of silicones, paraffins or waxes, are also used with advantage. The foam inhibitors, more particularly silicone- or paraffin-containing foam inhibitors, are preferably fixed to a granular water-soluble or water-dispersible support. Mixtures of paraffins and bis-stearyl ethylenediamides are particularly preferred.
The neutrally reacting sodium salts of, for example, 1-hydroxyethane-1,1-diphosphonate, diethylenetriamine pentamethylene phosphonate or ethylenediamine tetramethylene phosphonate are preferably used in quantities of 0.1 to 1.5% by weight as the salt of polyphosphonic acids.
Suitable enzymes are those from the class of proteases, lipases, amylases, cellulases and mixtures thereof. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus are particularly suitable. Proteases of the subtilisin type are preferably used, proteases obtained from Bacillus lentus being particularly suitable. Enzyme mixtures, for example mixtures of protease and amylase or protease and lipase or protease and cellulase or mixtures of cellulase and lipase or mixtures of protease, amylase and lipase or protease, lipase and cellulase, but especially cellulase-containing mixtures, are of particular interest. (Per)oxidases have also proved to be suitable in some cases. The enzymes may be adsorbed to supports and/or encapsulated in shell-forming substances to protect them against premature decomposition. The percentage content of enzymes, enzyme mixtures or enzyme granules may be, for example, of the order of 0.1 to 5% by weight and preferably from 0.1 to around 2% by weight.
The detergents according to the invention may contain derivatives of diaminostilbene disulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts, of 4,4xe2x80x2-bis-(2-anilino4-morpholino-1,3,5-triazinyl-6-amino)stilbene-2,2xe2x80x2-disulfonic acid or compounds of similar composition which contain a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group. Brighteners of the substituted diphenyl styryl type, for example alkali metal salts of 4,4xe2x80x2-bis-(2-sulfostyryl)-diphenyl, 4,4xe2x80x2-bis-(4-chloro-3-sulfostyryl)-diphenyl or 4-(4-chlorostyryl)4xe2x80x2-(2-sulfostyryl)-diphenyl, may also be present. Mixtures of the brighteners mentioned above may also be used.
The invention described in the foregoing is not confined to the coating of bleaching agents and bleach activators. On the contrary, any detergent ingredient may be coated in accordance with the invention and thus released through pH control. The parameters to be observed in this regard are generally the coating of the ingredient to be released through pH control with polymeric acids, the coating of an alkalizing agent with a material that dissolves slowly in water irrespective of the pH value of the wash liquor and the use of an uncoated acidifying agent which provides for a low starting pH value in the wash liquor. Because the water-soluble coating dissolves slowly, the wash liquor becomes increasingly more alkaline with the release of the alkalizing agent until, finally, the coating of the polymeric acid begins to dissolve at pH values above 8.5 and releases the ingredient to be released through pH control to the wash liquor. In other possible variants for example, acidic bleaching may be followed by the release of an agent which destroys the bleaching agent. A further delay can be achieved through the particular thickness of the coating so that the timing of the release process can be effectively determined.

pH-controlled release of detergent components


A formulated resin composition for producing a closed cell rigid polyisocyanate based foam is disclosed. The formulated resin composition for use in a polyurethane froth spraying system includes a hydrofluorocarbon blowing agent, a Mannich polyol, at least one additional polyol, a catalyst system, and a surfactant. The formulated resin composition has a hydroxyl content of at least 400 mg KOH/g and a polyurethane foam produced utilizing the formulated resin composition has a closed cell content of at least 90 percent. The formulated resin composition exhibits a zero ozone depleting potential and produces a polyurethane foam that cures faster than conventional sprayed polyurethane foams.

The present invention pertains to dimensionally stable closed cell spray rigid polyisocyanate based foams, and more particularly to foaming reaction mixtures which froth at a spray dispensing head, employing as a blowing agent a hydrofluorocarbon. With more particularity, the invention pertains to dimensionally stable closed cell spray rigid polyisocyanate based foams which froth at a spray dispensing head and the polyol resin blends used to make such foams.
Various hydrofluorocarbons (HFCS) have been investigated in the industry as blowing agents for polyisocyanate based foams due to their low or nonexistent ozone depletion potentials. It would be desirable to utilize a hydrofluorocarbon (HFC) blowing agent in a sprayable froth polyurethane system. Such a system would allow for production of an environmentally friendly closed cell polyurethane foam that exhibits improved cell structure and expands at a lower temperature range. It is also desirable to produce a polyurethane foam that avoids excessive creep and allows for improved dimensional stability.
The present invention provides a formulated resin composition for producing a closed cell rigid polyisocyanate based foam. In one embodiment the formulated resin composition for use in a polyurethane froth spraying system comprises: a hydrofluorocarbon blowing agent; a Mannich polyol; at least one additional polyol; a catalyst system; and a surfactant. The formulated resin composition has a hydroxyl content of at least 400 mg KOH/g and a polyurethane foam produced utilizing the formulated resin composition has a closed cell content of at least 90 percent.
The formulated resin composition exhibits a zero ozone depleting potential and produces a polyurethane foam that cures faster than conventional sprayed polyurethane foams.
A xe2x80x9cfroth foaming mixturexe2x80x9d is produced by a combination of a formulated isocyanate-reactive polyol stream containing a hydrofluorocarbon blowing agent with an organic polyisocyanate stream where the hydrofluorocarbon blowing agent sufficiently and spontaneously vaporizes when the two combined streams are exposed to atmospheric pressure upon discharge from a dispensing head to produce a froth. Thus, the hydrofluorocarbon acts as a frothing agent. It is to be understood that not all of the hydrofluorocarbon blowing agent needs to vaporize instantaneously from the two stream mixture when discharged, but at least an amount sufficient to produce a froth upon discharge from the dispensing head onto a substrate.
These mixtures are used to form both rigid and closed cell foams. The term a rigid foam is meant to describe a foam having a high ratio of compressive strength to tensile strength of 0.5:1 or greater and an elongation of 10 percent or less. The term a closed cell foam is meant to describe a foam having at least 85 percent closed cells and preferably 90 percent or more closed cells. The foams are polyisocyanate based meaning that they are made by reacting the isocyanate-reactive ingredients in a resin composition with an organic isocyanate or polyisocyanate. In preferred embodiments, all of the hydrofluorocarbon used as a frothing agent is added to the resin composition to form a formulated resin composition.
The formulated resin composition comprises a Mannich polyol, at least one additional polyol, a hydrofluorocarbon blowing agent, a polyurethane linkage promoting catalyst system, a surfactant, and, optionally, flame retardants, fillers, stabilizers, fungicides, pigments or dyes and bacteriostats.
A Mannich polyol is made by alkoxylating a Mannich compound, which is the condensation product of phenol or a substituted phenol, formaldehyde, and an alkanoamine, such as diethanol amine.
For example, the Mannich reaction is conducted by premixing the phenolic compound with a desired amount of the ethanolamine and then slowly adding formaldehyde to the mixture at a temperature below the temperature of Novolak formation. At the end of the reaction, water is stripped from the reaction mixture to provide a crude Mannich reaction product.
The Mannich reaction product is then alkoxylated with an alkylene oxide such as, for example, propylene oxide, ethylene oxide, or a mixture of propylene oxide and ethylene oxide. The alkylene oxide may suitably comprise from 100% to about 80% propylene oxide and from 0 to about 20 wt. % ethylene oxide. Alkoxylation of Mannich reaction products is described in U.S. Pat. Nos. 3,297,597 and 4,137,265, the disclosures of which are herein incorporated by reference.
The alkoxylation with propylene oxide is carried out by introducing the propylene oxide, preferably under pressure, into a vessel containing the Mannich reaction product. No added catalyst is needed since the basic nitrogen in this product provides sufficient catalytic activity to promote the reaction. Reaction temperatures between about 30xc2x0 C. and about 200xc2x0 C. may be employed, but the preferred reaction temperatures are in the range of from about 90xc2x0 to 120xc2x0 C. Under these conditions the phenolic hydroxyl group and the alkanolamino hydroxyls are reactive to form hydroxypropyl groups. Unreacted and partially reacted materials are removed from the final condensation product in any suitable manner (e.g., by vacuum stripping) to provide clear amber to brown liquids having hydroxyl numbers in the range of 400 to 550 and viscosities between about 4,000 and 45,000 centipoises at 25xc2x0 C.
In a preferred embodiment of the present invention the Mannich polyol is present in the formulated resin composition at an amount of from 20 to 40 weight percent, based on the total weight of the formulated resin composition.
The formulated resin composition also includes at least one additional polyol compound having at least two isocyanate-reactive hydrogens. The compounds having at least two isocyanate-reactive hydrogens preferably have an average hydroxyl number ranging from 150 to 800 mg KOH/g of compound.
Examples of these polyols include polythioether polyols, polyester amides and polyacetals containing hydroxyl groups, aliphatic polycarbonates containing hydroxyl groups, amine-terminated polyoxyalkylene polyethers, polyester polyols, and polyoxyalkylene polyether polyols. In addition, mixtures of at least two of the aforesaid polyols can be used.
The term xe2x80x9cpolyester polyolxe2x80x9d as used in this specification and claims includes any minor amounts of unreacted polyol remaining after the preparation of the polyester polyol and/or unesterified polyol (e.g., glycol) added after the preparation of the polyester polyol. The polyester polyol can include up to about 40 weight percent free glycol.
Suitable polyester polyols can be produced, for example, from organic dicarboxylic acids with 2 to 12 carbons, preferably aliphatic dicarboxylic acids with 4 to 6 carbons, and multivalent alcohols, preferably diols, with 2 to 12 carbons, preferably 2 to 6 carbons. Examples of dicarboxylic acids include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used individually or in mixtures. Instead of the free dicarboxylic acids, the corresponding dicarboxylic acid derivatives may also be used such as dicarboxylic acid mono- or di-esters of alcohols with 1 to 4 carbons, or dicarboxylic acid anhydrides. Dicarboxylic acid mixtures of succinic acid, glutaric acid and adipic acid in quantity ratios of 20-35:35-50:20-32 parts by weight are preferred, especially adipic acid. Examples of divalent and multivalent alcohols, especially diols, include ethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerine and trimethylolpropanes, tripropylene glycol, tetraethylene glycol, tetrapropylene glycol, tetramethylene glycol, 1,4-cyclohexane-dimethanol, ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or mixtures of at least two of these diols are preferred, especially mixtures of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. Furthermore, polyester polyols of lactones, e.g., xcex5-caprolactone or hydroxycarboxylic acids, e.g., xcfx89-hydroxycaproic acid, may also be used.
The polyester polyols can be produced by polycondensation of organic polycarboxylic acids, e.g., aromatic or preferably aliphatic polycarboxylic acids and/or derivatives thereof and multivalent alcohols in the absence of catalysts or preferably in an atmosphere of an inert gas, e.g., nitrogen, carbon dioxide, helium, argon, etc., in the melt at temperatures of 150xc2x0 to 250xc2x0 C., preferably 180xc2x0 to 220xc2x0 C., optionally under reduced pressure, up to the desired acid value which is preferably less than 10, especially less than 2. In a preferred embodiment, the esterification mixture is subjected to polycondensation at the temperatures mentioned above up to an acid value of 80 to 30, preferably 40 to 30, under normal pressure, and then under a pressure of less than 500 mbar, preferably 50 to 150 mbar. The reaction can be carried out as a batch process or as a continuous process. When present, excess glycol can be distilled from the reaction mixture during and/or after the reaction, such as in the preparation of low free glycol-containing polyester polyols usable in the present invention. Examples of suitable esterification catalysts include iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycondensation may also be preformed in liquid phase in the presence of diluents and/or chlorobenzene for aziotropic distillation of the water of condensation.
To produce the polyester polyols, the organic polycarboxylic acids and/or derivatives thereof and multi-valent alcohols are preferably polycondensed in a mole ratio of 1:1-1.8, more preferably 1:1.05-1.2.
After transesterification or esterification, the reaction product can be reacted with an alkylene oxide to form a polyester polyol mixture. This reaction desirably is catalyzed. The temperature of this process should be from about 80xc2x0 to 170xc2x0 C., and the pressure should generally range from about 1 to 40 atmospheres.
While the aromatic polyester polyols can be prepared from substantially pure reactant materials, more complex ingredients can be used, such as the side stream, waste or scrap residues from the manufacture of phthalic acid, terephthalic acid, dimethyl terephthalate, polyethylene terephthalate, and the like. Compositions containing phthalic acid residues for use in the invention are (a) ester-containing byproducts from the manufacture of dimethyl terephthalate, (b) scrap polyalkylene terephthalates, (c) phthalic anhydride, (d) residues from the manufacture of phthalic acid or phthalic anhydride, (e) terephthalic acid, (f) residues from the manufacture of terephthalic acid, (g) isophthalic acid, (h) trimellitic anhydride, and (i) combinations thereof. These compositions may be converted by reaction with the polyols of the invention to polyester polyols through conventional transesterification or esterification procedures.
Other materials containing phthalic acid residues are polyalkylene terephthalates, especially polyethylene terephthalate (PET), residues or scraps. Still other residues are DMT process residues, which are waste or scrap residues from the manufacture of dimethyl terephthalate (DMT). The term xe2x80x9cDMT process residuexe2x80x9d refers to the purged residue which is obtained during the manufacture of DMT in which p-xylene is converted through oxidation and esterification with methanol to the desired product in a reaction mixture along with a complex mixture of byproducts. The desired DMT and the volatile methyl p-toluate byproduct are removed from the reaction mixture by distillation leaving a residue. The DMT and methyl p-toluate are separated, the DMT is recovered and methyl p-toluate is recycled for oxidation. The residue which remains can be directly purged from the process or a portion of the residue can be recycled for oxidation and the remainder diverted from the process or, if desired, the residue can be processed further as, for example, by distillation, heat treatment and/or methanolysis to recover useful constituents which might otherwise be lost, prior to purging the residue from the system. The residue which is finally purged from the process, either with or without additional processing, is herein called DMT process residue.
Polyoxyalkylene polyether polyols, which can be obtained by known methods, are preferred for use as the additional polyhydroxyl compounds. For example, polyether polyols can be produced by anionic polymerization with alkali hydroxides such as sodium hydroxide or potassium hydroxide or alkali alcoholates, such as sodium methylate, sodium ethylate, or potassium ethylate or potassium isopropylate as catalysts and with the addition of at least one initiator molecule containing 2 to 8, preferably 3 to 8, reactive hydrogens or by cationic polymerization with Lewis acids such as antimony pentachloride, boron trifluoride etherate, etc., or bleaching earth as catalysts from one or more alkylene oxides with 2 to 4 carbons in the alkylene radical. Any suitable alkylene oxide may be used such as 1,3-propylene oxide, 1,2-and 2,3-butylene oxide, amylene oxides, styrene oxide, and preferably ethylene oxide and 1,2-propylene oxide and mixtures of these oxides. The polyalkylene polyether polyols may be prepared from other starting materials such as tetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures; epihalohydrins such as epichlorohydrin; as well as aralkylene oxides such as styrene oxide. The polyalkylene polyether polyols may have either primary or secondary hydroxyl groups.
Included among the polyether polyols are polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polytetramethylene glycol, block copolymers, for example, combinations of polyoxypropylene and polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethylene glycols, poly-1,4-tetramethylene and polyoxyethylene glycols, and copolymer glycols prepared from blends or sequential addition of two or more alkylene oxides. The polyalkylene polyether polyols may be prepared by any known process such as, for example, the process disclosed by Wurtz in 1859 and Encyclopedia of Chemical Technology, Vol. 7, pp. 257-262, published by Interscience Publishers, Inc. (1951) or in U.S. Pat. No. 1,922,459.
Polyethers which are preferred include the alkylene oxide addition products of polyhydric alcohols such as ethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, hydroquinone, resourcinol glycerol, glycerine, 1,1,1-trimethylol-propane, 1,1,1-trimethylolethane, pentaerythritol, 1,2,6-hexanetriol, a-methyl glucoside, sucrose, and sorbitol. Also included within the term xe2x80x9cpolyhydric alcoholxe2x80x9d are compounds derived from phenol such as 2,2-bis(4-hydroxyphenyl)-propane, commonly known as Bisphenol A.
Particularly preferred additional polyether polyols of the present invention include: Voranol(copyright) 370, a sucrose based polyether polyol having a hydroxyl number of approximately 370 and commercially produced by the Dow Chemical Company, Pluracol(copyright) 450 and 550 polyether tetrols having hydroxyl numbers of approximately 560 and 450, respectively and commercially produced by BASF Corporation, LHT-240 a polyether triol having a hydroxyl number of approximately 270 and commercially produced by AC West Virginia Polyol Company.
Suitable organic amine initiators which may be condensed with alkylene oxides include aromatic amines such as aniline, N-alkylphenylenediamines, 2,4xe2x80x2-2,2xe2x80x2, and 4,4xe2x80x2-methylenedianiline, 2,6- or 2,4-toluenediamine, vicinal toluenediamines, o-chloro-aniline, paminoaniline, 1,5-diaminonaphthalene, methylene dianiline, the various condensation products of aniline and formaldehyde, and the isomeric diaminotoluenes; and aliphatic amines such as mono-, di-, and trialkanolamines, ethylene diamine, propylene diamine, diethylenetriamine, methylamine, ethanolamine, diethanolamine, N-methyl- and N-ethylethanolamine, N-methyl- and N-ethyldiethanolamine, triethanolamine, triisopropanolamine, 1,3-diaminopropane, 1,3-diaminobutane, and 1,4-diaminobutane. Preferable amines include polyoxypropylenediamine, such as Jeffamine(copyright) D-230 commercially produced by Huntsman Corporation.
It is to be understood that the polyols initiated by an amine can also be initiated with a polyhydric alcohol, such as when a mixed initiator of an aliphatic amine/-polyhydric alcohol is used like an amine/sucrose package.
Suitable polyhydric polythioethers which may be condensed with alkylene oxides include the condensation product of thiodiglycol or the reaction product of a dicarboxylic acid such as is disclosed above for the preparation of the hydroxyl-containing polyesters with any other suitable thioether glycol.
The hydroxyl-containing polyester may also be a polyester amide such as is obtained by including some polyester amide such as is obtained by including some amine or amino alcohol in the reactants for the preparation of the polyesters. Thus, polyester amides may be obtained by condensing an amino alcohol such as ethanolamine with the polycarboxylic acids set forth above or they may be made using the same components that make up the hydroxyl-containing polyester with only a portion of the components being a diamine such as ethylene diamine. Suitable polyacetals which may be condensed with alkylene oxides include the reaction product of formaldehyde or other suitable aldehyde with a dihydric alcohol or an alkylene oxide such as those disclosed above.
Suitable aliphatic thiols which may be condensed with alkylene oxides include alkanethiols containing at least two xe2x80x94SH groups such as 1,2-ethanedithiol, 1,2-propanedithiol, 1,2-propanedithiol, and 1,6-hexanedithiol; alkene thiols such as 2-butene-1,4-dithiol; and alkyne thiols such as 3-hexyne-1,6-dithiol.
The closed cell rigid polyisocyanate based foam of the invention is blown with a physically active blowing agent, such as, a C1-C4 hydrofluorocarbon having a boiling point of 300K or less.
Physically active blowing agents are those which boil at the exotherm foaming temperature or less, preferably at 50xc2x0 C., or less. The most preferred physically active blowing agents are those which have a zero ozone depletion potential. Examples of physically active blowing agents are the volatile non-halogenated hydrocarbons having two to seven carbon atoms such as alkanes, alkenes, cycloalkanes having up to 6 carbon atoms, dialkyl ether, cycloalkylene ethers and ketones; and hydrofluorocarbons (HFCs).
Examples of volatile non-halogenated hydrocarbons include linear or branched alkanes, e.g. butane, isobutane, 2,3-dimethylbutane, n- and isopentane and technical-grade pentane mixtures, n- and isohexanes, n- and isoheptanes, n- and isooctanes, n- and isononanes, n- and isodecanes, n- and isoundecanes, and n- and isodedecanes. Since very good results are achieved with respect to the stability of emulsions, the processing properties of the reaction mixture and the mechanical properties of polyurethane foam products produced when n-pentane, isopentane or n-hexane, or a mixture thereof is used, these alkanes are preferably employed. Furthermore, specific examples of alkenes are 1-pentene, 2-methylbutene, 3-methylbutene, and 1-hexene; of cycloalkanes are cyclobutane, preferably cyclopentane, cyclohexane or mixtures thereof; specific examples of linear or cyclic ethers are dimethyl ether, diethyl ether, methyl ethyl ether, vinyl methyl ether, vinyl ethyl ether, divinyl ether, tetrahydrofuran and furan; and specific examples of ketones are acetone, methyl ethyl ketone and cyclopentanone. Preferentially, cyclopentane, n- and isopentane, n-hexane, and mixtures thereof are employed.
Suitable hydrofluorocarbons include difluoromethane (HFC-32); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1-difluoroethane (HFC-152a); 1,2-difluoroethane (HFC-142), trifluoromethane; heptafluoropropane (R-227a); hexafluoropropane (R-136; 1,1,1-trifluoroethane; 1,1,2-trifluoroethane; fluoroethane (R-161); 1,1,1,2,2-pentafluoropropane; pentafluoropropylene (R-2125a); 1,1,1,3-tetrafluoropropane; tetrafluoropropylene (R-2134a); difluoropropylene (R-2152b); 1,1,2,3,3-pentafluoropropane; 1,1,1,3,3-pentafluoro-n-butane; and 1,1,1,3,3-pentafluoropentane (245fa).
In a preferred embodiment, the physically active blowing agent is at least 1,1,1,2-tetrafluoroethane (HFC-134a) and more preferably HFC-134a is the sole physically active blowing agent used because of its wide availability, its zero ozone-depletion potential, and its excellent frothing characteristics.
HFC-134a has a boiling point of 247 K. (xe2x88x9226xc2x0 C. at 760 mm/Hg) and readily vaporizes at atmospheric pressure to froth a foaming mixture as it exits a dispensing head. The HFC-134a is also known by the abbreviation R-134a. The R-134a may be added to the formulated resin composition at the dispensing head as a separate stream; blended into the formulated resin composition tank immediately prior to dispensing; or it may be pre-blended into the formulated resin composition, stored, and shipped in pressurized containers to a manufacturer of the foams of the present invention. To make a formulated resin composition by any of these methods, R-134a is liquified under pressure, metered into the formulated resin composition, and, optionally, but preferably blended until a homogenous solution is formed. In one embodiment the tanks containing the formulated resin composition are pressurized at 150-300 psig, and depending on the type of dispensing method employed as discussed further below, may also be pre-combined with an inert gas such as nitrogen. In this embodiment, the R-134a is present in an amount of from 7 to 10 weight percent based on the total weight of the formulated resin composition.
In another embodiment, the formulated resin composition is stored in a fifty-gallon drum at atmospheric pressure. The R-134a is present in an amount of from 3 to 6 weight percent based on the total weight of the formulated resin composition.
The amount of R-134a employed will depend upon the desired density of the foam and the limits of its solubility in a particular formulated polyol composition. To reduce costs, it is always advantageous to keep the amount of R-134a to a minimum within the desired density range.
Catalysts may be employed which greatly accelerate the reaction of the compounds containing isocyanate-reactive hydroxyl groups with the modified or unmodified polyisocyanates. Examples of suitable catalysts are cure catalysts which also function to shorten tack time, promote green strength and prevent foam shrinkage. Suitable cure catalysts are organometallic catalysts, preferably organo-lead catalysts, although it is possible to employ metals such as tin, titanium, copper, mercury, cobalt, nickel, iron, vanadium, antimony and manganese. Preferred cure catalysts include lead octoate and lead napthanate.
Tertiary amines also promote urethane linkage formation, and examples include triethylamine,3-methoxypropyldimethylamine, triethylenediamine, tributylamine, dimethylcyclohexylamine, dimethylbenzylamine, N-methyl-, N-ethyl- and N-cyclohexylmorpholine, N,N,Nxe2x80x2,Nxe2x80x2-tetramethylethylenediamine, N,N,Nxe2x80x2,Nxe2x80x2-tetramethylbutanediamine or-hexanediamine, N,N,Nxe2x80x2-trimethyl isopropyl propylenediamine, pentamethyldiethylenetriamine, tetramethyldiaminoethylether, bis(-dimethylaminopropyl)urea, dimethylpiperazine, 1-methyl-4-dimethylaminoethylpiperazine, 1,2-dimethylimidazole, 1-azabicylo[3.3.0]octane and preferably 1,4-diazabicylo[2.2.2]octane, and alkanolamine compounds, such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine and dimethylethanolamine.
Tertiary amine ether blow catalysts may also be used. Typical tertiary amine ether blow catalysts include, but are not limited to, N,N,N,Nxe2x80x3-tetramethyl-2,2xe2x80x2-diaminodiethyl ether; 2-dimenthyaminoethyl-1,3-dimenthylamineopropyl ether; and N,N-dimorpholinoethyl ether. Most preferred is pentamethyldiethylenetriamine.
The blow catalyst can be used in its pure form or dissolved in a carrier such as a glycol. When a catalyst is employed which is dissolved in a carrier, the amounts stated herein by weight percent refer to the amount of catalyst and do not include the weight of the carrier.
Preferably, the catalyst system of the present invention includes at least one cure catalyst and at least one blow catalyst outlined above, as well as a gelation catalyst, such as triethylenediamine in a dipropylene glycol carrier, which is commercially produced under the trade name Dabco(copyright) LV-33 by the Air Products Corporation.
The formulated resin composition preferably also contains a flame retardant. Examples of suitable phosphate flame retarding agents are tricresyl phosphate, tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, and tris(2,3-dibromopropyl) phosphate. In addition to these halogen-substituted phosphates, it is also possible to use inorganic or organic flame retarding agents, such as red phosphorous, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate (Exolit(copyright)) and calcium sulfate, molybdenum trioxide, ammonium molybdate, ammonium phosphate, pentabromodiphenyloxide, 2,3-dibromopropanol, hexabromocyclododecane, dibromoethyldibromocyclohexane, expandable graphite or cyanuric acid derivatives, e.g., melamine, or mixtures of two or more flame retarding agents, e.g., ammonium polyphosphates and melamine, and, if desired, corn starch, or ammonium polyphosphate, melamine, and expandable graphite and/or, if desired, aromatic polyesters, in order to flame retard the polyisocyanate polyaddition products. In general, from 2 to 40 percent, preferably from 5 to 20 percent, of said flame retarding agents may be used, based on the weight of the formulated resin composition.
Examples of suitable surfactants that may be used are compounds which serve to support homogenization of the starting materials and may also regulate the cell structure of the foams. Specific examples are salts of sulfonic acids, e.g., alkali metal salts or ammonium salts of fatty acids such as oleic or stearic acid, of dodecylbenzene- or dinaphthylmethanedisulfonic acid, and ricinoleic acid; foam stabilizers, such as siloxaneoxyalkylene copolymers and other organopolysiloxanes, oxyethylated alkyl-phenols, oxyethylated fatty alcohols, pariffin oils, castor oil esters, ricinoleic acid esters, Turkey red oil and groundnut oil, and cell regulators, such as paraffins, fatty alcohols, and dimethylpolysiloxanes. The surfactants are usually used in amounts of 0.01 to 5% based on the weight of the formulated resin composition. A particularly preferred non-silicone surfactant is LK-443 commercially produced by Air Products Corporation.
The organic polyisocyanates that may be used in the present invention include all essentially known aliphatic, cycloaliphatic, araliphatic and preferably aromatic multivalent isocyanates. Specific examples include: alkylene diisocyanates with 4 to 12 carbons in the alkylene radical such as 1,12-dodecane diisocyanate, 2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, 1,4-tetramethylene diisocyanate and preferably 1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as 1,3- and 1,4-cyclohexane diisocyanate as well as any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluene diisocyanate as well as the corresponding isomeric mixtures 4,4xe2x80x2,2,2xe2x80x2- and 2,4xe2x80x2-dicyclohexylmethane diisocyanate as well as the corresponding isomeric mixtures and preferably aromatic diisocyanates and polyisocyanates such as 2,4- and 2,6-toluene diisocyanate and the corresponding isomeric mixtures 4,4xe2x80x2-, 2,4xe2x80x2- and 2,2xe2x80x2-diphenylmethane diisocyanate and the corresponding isomeric mixtures, mixtures of 4,4xe2x80x2- and 2,4xe2x80x2-diphenylmethane diisocyanates and polyphenylenepolymethylene polyisocyanates (polymeric MDI), as well as mixtures of polymeric MDI and toluene diisocyanates. The organic di- and polyisocyanates can be used individually or in the form of mixtures.
Frequently, so-called modified multivalent isocyanates, i.e., products obtained by the partial chemical reaction of organic diisocyanates and/or polyisocyanates are used. Examples include diisocyanates and/or polyisocyanates containing ester groups, urea groups, biuret groups, allophanate groups, carbodiimide groups, isocyanurate groups, and/or urethane groups. Specific examples include organic, preferably aromatic, polyisocyanates containing urethane groups and having an NCO content of 33.6 to 15 weight percent, preferably 32 to 21 weight percent, based on the total weight, e.g., with low molecular weight diols, triols, dialkylene glycols, trialkylene glycols, or polyoxyalkylene glycols with a molecular weight of up to 1500; modified 4,4xe2x80x2-diphenylmethane diisocyanate or 2,4- and 2,6-toluene diisocyanate, where examples of di- and polyoxyalkylene glycols that may be used individually or as mixtures include diethylene glycol, dipropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, and polyoxypropylene polyoxyethylene glycols or -triols. Prepolymers containing NCO groups with an NCO content of 25 to 9 weight percent, preferably 21 to 14 weight percent, based on the total weight and produced from the polyester polyols and/or preferably polyether polyols described below; 4,4xe2x80x2-diphenylmethane diisocyanate, mixtures of 2,4xe2x80x2- and 4,4xe2x80x2-diphenylmethane diisocyanate, 2,4,- and/or 2,6-toluene diisocyanates or polymeric MDI are also suitable. Furthermore, liquid polyisocyanates containing carbodiimide groups having an NCO content of 33.6 to 15 weight percent, preferably 32 to 21 weight percent, based on the total weight, have also proven suitable, e.g., based on 4,4xe2x80x2- and 2,4xe2x80x2- and/or 2,2xe2x80x2-diphenylmethane diisocyanate and/or 2,4xe2x80x2- and/or 2,6-toluene diisocyanate. The modified polyisocyanates may optionally be mixed together or mixed with unmodified organic polyisocyanates such as 2,4xe2x80x2- and 4,4xe2x80x2-diphenylmethane diisocyanate, polymeric MDI, 2,4xe2x80x2- and/or 2,6-toluene diisocyanate.
Organic polyisocyanates which may be employed include aromatic, aliphatic, and cycloaliphatic polyisocyanates and combinations thereof. Representative of these types are the diisocyanates such as m-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, cyclohexane-1,4-diisocyanate, hexahydrotoluene diisocyanate (and isomers), naphthalene-1,5-diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, 4,4xe2x80x2-diphenylmethane diisocyanate, mixtures of 4,4xe2x80x2- and 2,4xe2x80x2-diphenylmethane diisocyanate, 4,4xe2x80x2-biphenylene diisocyanate, 3,3xe2x80x2-dimethoxy-4,4xe2x80x2-biphenyl diisocyanate, 3,3xe2x80x2-dimethyl-4,4xe2x80x2-biphenyl diisocyanate and 3,3xe2x80x2-dimethyldiphenylmethant-4,4xe2x80x2-diisocyanate; the triisocyanates such as 4,4xe2x80x2,4xe2x80x3-triphenylmethane triisocyanate, and toluene 2,4,6-trisocyanate; and the tetraisocyanates such as 4,4xe2x80x2-dimethldiphenylmethane-2,2xe2x80x2,5,5xe2x80x2-tetraisocyanate and polymeric polyisocyanates such as polymethylene polyphenylene polyisocyanate, and mixtures thereof. Especially useful due to their availability and properties are 4,4xe2x80x2-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, or mixtures thereof for rigid foams, or a mixture of the foregoing with toluene diisocyanates for semi-rigid foams.
Crude polyisocyanates may also be used in the compositions of the present invention, such as crude toluene diisocyanate obtained by the phosgenation of a mixture of toluenediamines or crude diphenylmethane isocyanate obtained by the phosgenation of crude isocyanates as disclosed in U.S. Pat. No. 3,215,652.
In a first embodiment, the foaming apparatus comprises at least one reactant supply tank for imposing gas pressure to drive the reactants from the supply tanks and a fixed ratio positive displacement pump, specifically designed for the spray application of rigid polyurethane cellular foams.
The organic isocyanate reactant or an organic isocyanate-terminated quasi-prepolymer or prepolymer may be supplied in bulk, totes, drums or supply tanks.
Any means for imposing pressure to drive the reactants from the supply tanks may be used. Typically, a pressurized gaseous inert propellant, such as a nitrogen tank, is used having valved outlets communicating via suitable conduits with the inlets to the supply tanks. The supply tanks are kept under pressure to provide the driving force needed to propel the reactants from the supply tanks and to liquefy the R-134a blowing agent in the formulated resin compositions supply tank(s). The pressure in the supply tanks is generally 150-300 psig.
It is generally necessary, for the proper functioning of the foaming apparatus, that the viscosity of the contents of each of the supply tanks be no greater than about 1200 cps at 78xc2x0 F. And more preferably no more than about 800 cps. This, of course, means that the materials in each tank may have to be properly selected or formulated, as the case may be, in order to meet this viscosity requirement. The viscosity values mentioned herein are measured at 78xc2x0 F. and at 80 psig. The viscosity of supply tanks contents are measured under a pressure of 80 psig because of the presence of R-134a in liquid form.
By using a fixed ratio, positive displacement pump, specifically designed for the spray application of rigid polyurethane cellular foams, the volume ratio of the isocyanate stream and the formulated resin composition stream can be held at 1:1.
In a second embodiment, the foaming apparatus comprises a first product drum containing the formulated resin composition and a second drum containing the polyisocyanate component. The liquids are supplied to a spray dispensing head via transfer pumps. The volume ratio of the isocyanate stream and the formulated resin composition stream is held at 1:1.
The following examples are intended to illustrate, but in no way limit, the scope of the present invention. The foaming apparatuses used in this example comprised: (a) a first supply tank for supplying the isocyanate reactant, (b) a second supply tank for supplying the formulated resin composition, (c) a nitrogen pressure tank having a valved outlet in communication, via a distributing valve, with the inlets to the two supply tanks, and (d) a fixed ratio positive displacement pump designed for the spray application of rigid polyurethane foam for a first embodiment; and (a) a first drum for supplying the isocyanate reactant, (b) a second drum for supplying the formulated resin composition, (c) transfers pumps for supplying the components to a spray dispensing head.
The polyols employed in the working examples are defined as follows:
Polyol A is an aromatic, amino, Mannich polyol which is commercially available from Huntsman with a nominal hydroxyl number of approximately 470.
Polyol B is polyether tetrol under the name Pluracol(copyright) 450 commercially available from BASF with a nominal hydroxyl number of 540-570.
Polyol C polyether tetrol under the name Pluracol(copyright) 550 commercially available from BASF with a nominal hydroxyl number of 435-465.
Polyol D is a sucrose based polyether polyol under the name of Voranol(copyright) 370 commercially available from Dow Chemical with a nominal hydroxyl number of 370.
Polyol E is a polyether triol under the name LHT-240 commercially available from AC West Virginia Polyol with a nominal hydroxyl number of 270.
PCF is trichloropropylphosphate, a flame retardant. available from Great Lakes Chemical.
Fyrol 6 is a flame retardant available from Great Lakes Chemical.
Lead is a Lead octoate catalyst.
LK-443 is a non-silicone surfactant commercially available from Air Products.
D-33LV is triethylenediamine in dipropylene glycol, commercially available from Air Products.
D-230 is polyoxypropylenediamine commercially available from Huntsman.
PC-5 is Polycat(copyright) 5 a tertiary amine catalyst commercially available from Air Products.
R-134a is 1,1,1,2-tetrafluoroethane, a hydrofluorocarbon blowing agent.

Sprayable autofrothing polyisocyanate foam and delivery system