NZ202842A

NZ202842A - Crack-resistant detergent bar containing fatty acid soaps

Info

Publication number: NZ202842A
Application number: NZ202842A
Authority: NZ
Inventors: G F Marion; D P Joshi; H E Wixon
Original assignee: Colgate Palmolive Co
Priority date: 1981-12-23
Filing date: 1982-12-17
Publication date: 1986-05-09
Also published as: ES518474A0; AU9177582A; DK564982A; DE3246796A1; ES8405840A1; ZA829339B; FR2518568A1; CA1203143A; GB2114145B; FR2518568B1; GB2114145A; AU550951B2

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £02842 2 02842 Priority Date(s): 93;.'?.. ,^.' Complete Specification Filed: AT..I?. Class: Publication Date: ... ("!4T. I98f>. P.O. Journal, No: . I Patents Form No. 5 Number PATENTS ACT 1953 Dated COMPLETE SPECIFICATION CRACK-RESISTANT DETERGENT BAR p/We COLGATE-PALMOLIVE COMPANY of 300 Park Avenue, New York, New I York 10022, United States of America, a corporation organised under the laws of the State of Delaware, United States of Americ do hereby declare the invention for which p/we pray that a Patent may be granted to mk/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 - 2 02842 This invention relates to detergent bars and especially to the provision of detergent bars having a basis of fatty acid soap as the predominant wash-active agent and having improved resistance to wet cracking and embrittlement . There exist a number of prior art disclosures of soap bars in which polycarboxylic acids, including aliphatic dicarboxylic acids, have been incorporated for various purposes. Thus, U.S. 1,68U,336 of Sept. 11, 1928 discloses a medicinal soap bar containing rectified amber oil and about 2? of succinic acid 10 to provide hyperaemia with consequent heating. U.S. 2 ,792 ,3^*8 of May lU, 1957 discloses the addition of 1% to 10% of aliphatic dibasic acids of 3 to 10 carbon atoms as a hardness - increasing agent in soap bars, especially those derived from unsaturated fatty acids, U.S. 3 ,085 ,066 of April 9 , 1963 discloses the use of 15 about 0.01? to 0.5$, up to 10$, of an alkanedioc acid of 2 to 10 carbon atoms as a color stabilizer in an antiseptic soap bar containing a discoloring type of bacteriostat. U.S. 3,557,006 of Jan. 19, 1971 discloses the very same dibasic acid-containing soap bars as U.S. 2,792,3^8 but the acid is relied upon to provide 20 on the skin the normal acidic skin pH. British U8l,U8l accepted March 11, 1938 discloses the addition to soap bars bleached with boric acid of a very small amount (about 0.1?) of a hydroxypoly basic aliphatic acid such as tartaric or citric acid for neutralization of excess alkali and to provide resistance to discoloration, 25 cracking and embrittlement. British 1,^60,^42 published Jan. 6, 1977 discloses soap bars containing, as skin moisturizers, 5'to 55? Clj-io aliphatic dicarboxylic acids and/or hydroxy polycarboxylic acids. U.K. Patent Application GB 2,OOU,56^A published Apr. U, 1979 discloses the concept of reacting a neutral fatty acid soap with 30 about 0.1? to 3? of a aliphatic dicarboxylic acid which -2- 202842 yields the corresponding soap of the dicarboxylic acid and concurrently releases an equivalent desired amount of free (superfatting) fatty acid. In British Patent Specific-ation 2,068,997 soap bars are disclosed containing, as anti-wet cracking agent, about 1$ to about 5% of adipic, azelaic or tartaric acid. In British Patent Specification 2,075,044 ~ soap bars are disclosed containing, as anti- wet cracking agent, about 1% to about 3% of a mixture of Cit_2Q polycarboxylic acids, at least 20% of the mixture comprising straight chain dicarboxylic acid of no more than 9 carbon atoms. Wet-cracking refers to the known defect of soap bars in developing cracks when repeatedly moistened and dried. Such soap bars containing polycarboxylic, and especially dicarboxylic, acids are however more or less disadvantageous for several reasons. Thus, it has been found that these acids tend to make the soap "short" or brittle upon extrusion, thus showing its non-plasticity. Furthermore, these acids have high melting points and in their original state are hard dry particles not readily miscible with the soap during processing. This reduced miscibility not only renders the processing more difficult and costly, but also reduces the anti-wet cracking efficiency of the acid in the soap bar. These acids also tend to reduce the water solubility and/or lathering properties of the soap bar, especially in cold, hard water. Further, these soap bars, being still on the alkaline side because of the relatively small amount of acid contained therein, exert a recognized degree of skin irritation in use. It is an object of this invention to provide soap bars and methods of making them which will not be subject to one or more of the above disadvantages. Other objects and advant nf.CL; I" N.2. PATENT o;-\ -3- j" " 06 JAN 193-6 RECEtVTO _____' 2 02842 will appear as the description proceeds. The attainment of the above objects is made possible by this invention which includes the provision of a detergent bar comprising, approximately by weight, at least 10% of a Cq_20 5 fatty acid salt, 0.5% to less than 5% of one or a mixture of hydrocarbyl or hydroxyhydrocarbyl polycarboxylic acids of 2 to about 20 carbon atoms, and 1% to less than 25% of one or a mixture of ethoxameric nonionic surface active agents. According to another aspect of this invention, a 10 preferred method for making the aforementioned detergent bar comprises dissolving the polycarboxylic acid in the nonionic surface active agent and mixing the resulting solution with the fatty acid salt. According to yet another aspect of this invention, a 15 washing method is provided comprising contacting the human body with the aforementioned detergent bar in the presence of water. The nonionic surface active agent included in the polycarboxylic acid-containing detergent bars of this invention reduces or eliminates the tendency of the bars to become brittle, 20 further improves their resistance to wet-cracking, improves their solubility and lathering properties in use in water, especially cold, hard water, exerts an emollient or anti-irritation effect on the skin, and renders the soap composition more plastic and more easily and economically processed into bars. Pre-dissolving 25 the polycarboxylic acid anti-wet cracking agent in the nonionic surface active agent further facilitates uniform mixing into the soap composition and improves the efficiency of the anti-wet cracking agent in the bar. The predominant wash-active agent in the detergent bars 30 ol' this invention may be any conventional soap, otherwise referred -h- 2 02842 to as fatty acid .''.alt. The soap may be derived from one or a mixture of Cg_2o> preferably C12_i8' straight or branched chain, saturated or unsaturated monocarboxylic acids, of natural or synthetic origin. Natural sources, e.g. animal, marine or 5 .vegetable fats and oils, almost always yield mixtures of these fatty acids, all of which may be employed. Examples thereof include the fatty acids derived from coconut oil, olive oil, palm kernel oil, tall oil, soy bean oil, cottonseed oil, peanut oil, safflower oil, sunflower seed oil, corn oil, fish oils, 10 tallow, and the like. Illustratively, individual fatty acids include capric, lauric, myristic, stearic, oleic, palmitoleic , ricinoleic, linoleic, linoleric acids and the like. The fatty ao.ids may also be derived synthetically by paraffin oxidation, Oxo-synthesis , or the like. The cation or salt portion of the 15 soap is preferably an alkali metal such as potassium and, especially, sodium, but may alternatively be an alkaline earth metal such as calcium or magnesium, ammonium, substituted ammonium, or organic amine such as lower alkylamines and lower alkanolamines. Mixtures of the fatty acids may be employed. 20 Preferred are 1»/1 to 7/1, especially about 3/1 to 5/1, tallow/coco I sodium soaps. The fatty acid salt typically constitutes at least about 70$ , preferably at least about 80% , by weight of the detergent bars of this invention. The polycarboxylic acid component may be unsaturated but ^25 preferably saturated, and aromatic, alicyclic but preferably aliphatic, branched but preferably straight chain, and hydroxy-substituted but preferably unsubs.tituted , and hexa-, penta-, tetra-, tri- but preferably di-carboxylic , and of 2 to about 20, preferably 2 to about 10, carbon atoms. Alkanedioc and hydroxyalkanedioc 30 acids of 2 to about 10 carbon atoms are especially preferred, -5- 2 02842 particularly adipic and azelaic acids. As illustrative of other suitable hydrocarbyl and hydroxyhydrocarbyl polycarboxylic acids, there may be mentioned oxalic, malonic, succinic, glutaric, pimelic, suberic, sebacic, methyl adipic, citric, malic, tartaric, 5 dihydroxytartaric , fumaric, maleic, itaconic, aconitic, hexenedioc, heptenedioc , phthalic, 3-hydroxyphthalic, cyclohexyldicarboxylic , 3-cyclohexyl- dicarboxylic, mellitic, hexahydromellitic, mello-phanic and the like. Mixtures of two or more such acids may be employed. The polycarboxylic acid component, which may 10 optionally be in anhydride form and/or at least partially in salt form, typically constitutes about 0.5% to less than 5%, preferably about 1% to about 2%, by weight of the detergent bars of this invention. The nonionic surfactants (surface active agents) useful 15 in the present invention are well known materials and may be broadly defined as water soluble products derived from the condensation of a plurality of moles of a C2_3 alkylene oxide or equivalent reactant (hydrophilic in nature) with a reactive hydrogen-containing organic hydrophobic compound which may be 20 aliphatic, aromatic, alicyclic or heterocyclic. The length of the hydrophilic polyoxyalkylene chain in the condensation product derived from any particular hydrophobe can be readily adjusted to provide water solubility and the desired degree of balance between hydrophilic and hydrophobic or lipophilic elements ^^5 (HLB factor). Although propylene oxide may be employed as the alkylene oxide reactant, ethylene oxide is most commonly employed, more effective and preferred herein. These polyoxyethylene-containing condensation products have been referred to as ethoxamers or ethoxameric i 30 nonionic surfactants. -6- 2 028 42 The precursor hydrophobe of the nonionic surfactant may contain from about 6, preferably from about 8, up to 50 or more carbon atoms and at least one reactive hydrogen-containing moiety as present for example in aliphatic nlcoholr. , alky] 5 phenols, carboxylic acids, carboxylic ucid amides, sulfonamides, 'amines, and the like. As a general rule, at least about 1+ moles of ethylene oxide should be reacted per mole of hydrophobe, but ^ up to 200 moles of ethylene oxide may be so reacted depending ' on the hydrophobe, desired water solubility, surface activity, 10 emolliency, plasticity and melting point, and the like. The ^ nonionic surfactant should be liquifiable, e.g. at elevated temperatures up to about 90°C, to facilitate processing of the I soap composition into bar form. Representative operative nonionic surfactants include 15 polyoxyethylene polyoxypropylene block polymers (Pluronics) and other types as disclosed for example in the portion of U.S. h,1^0,6141 issued February 20 , 1979 to Ramachandran from line 3 to line 63 of column 2, which portion is incorporated herein by reference thereto. As exemplary of specific nonionic surfactants, 20 mention is made of dinonyl phenol + 15 E.0. (l mole of dinonyl phenol reacted with 15 moles of ethylene oxide), dodecyl ) mercaptan +10 E.O., lauramide + 8 E.0., stearic acid + 20 E.0., ) tetradecyl amine + lit E.Oi, dodecyl sulfonamide + 6 E.0., and myristyl alcohol + 10 E.0. Preferred are condensation products 25 of one mole of an alkanol, preferably straight chain and primary, ^ of about 9 to 20, especially 10 to 18, carbon atoms with about ' H to 20, especially 5 to 15, moles of ethylene oxide, as represented for example by Neodol 23-65 (^12-13 alkanol + 6.5 E.0.) and Neodol 1+5-13 (C]_l*-15 alkanol + 13 E.0.). The nonionic surfactant component 30 typicEtlly constitutes about 1$ to less than 25$, preferably about 2 to less than 10$, more preferably about 2.5$ to less than 5$, -7- 2 028 4 2 by weight of the detergent bars of this invention. As indicated in the examples below, inclusion of this nonionic surfactant component in polycarboxylic acid-containing detergent (soap) bars enables the attainment of equal or better resistance to wet cracking with a 5 substantially lower proportion of the polycarboxylic acid. The nonionic surfact ant/polycarboxylic acid weight ratio preferably ranges from about 0.5/1 to about 5/1, more preferably about 1/1 to about 2/1, especially about 1.5/1- The detergent bars of this invention generally contain 10 about 8$ to about 16$ , more usually about 10$ to about lh% , by weight of water, and optionally other conventional additives such as super-fatting agents, perfumes, coloring matter, anti-oxidants, non-soap organic anionic surfactants, proteins, binding agents, sequestrants, foam boosters, optical brighteners, preservatives, bacteriostats , 15 and inorganic salt fillers and builders and the like in conventional proportions of about 0.01$ to about 25$ by weight of the detergent bar . In preparing the detergent bars of this invention, the polycarboxylic acid and nonionic surfactant components may be 20 incorporated into the soap at any stage of processing into bar form, preferably by admixture with the previously prepared soap chips in the crutcher or, more preferably, the amalgamator. According to a further feature of the invention, the polycarboxylic acid component is first dissolved or dispersed in the liquid or 25 liquified nonionic surfactant (e.g. by heating up to about 90°C. if needed) and the resulting solution (or dispersion) then admixed with the fatty acid salt-containing soap composition, followed by conventional extrusion and pressing into bar form. The wet cracking test, results of which are given in the 30 following examples, involves immersing the bur (of about 100 grams) -8- 202842 in water at about 2li°C. for ^ hours, removing and hanging the bar 10 15 20 k2 5 to dry and then evaluating for cracks. The severity of the cracks are rated on a scale of 0 to 5, no cracks of any kind being assigned a severity rating of 0, very tiny cracks being assigned a severity rating of 1, larger cracks 2 to h depending on size, and 5 when the bar is badly cracked or split. The severity rating multiplied by the number of cracks is the cracking rating, averaged for reliability on a substantial number (e.g. 31) of bars concurrently produced from the same composition. The following examples are only illustrative. All amounts and proportions referred to herein and in the appended claims are by weight unless otherwise indicated. Example 1 A solution of 2 parts by weight of adipic acid in 3 parts by weight of Neodol 23-6.5 (^22-13 alkanol + 6.5 E.0.) is prepared at about 65°C. The solution is then processed in a conventional amalgamator with, approximately by weight, 92 parts of 5/1 tallow/ coco sodium soap chips of 11% moisture content, 0.1 parts of 50$ aqueous stannic chloride (color and fragrance stabilizer), 0.5 parts of titanium dioxide, 1.25 parts of bacteriostat , 0.5 parts of glycerin, 1.5 parts of perfume, and 0.5 parts of a 10$ color solution. The mixture is then shaped into bars of about 100 grams each in conventional manner including extrusion and pressing, and tested for wet cracking as described above, together with control bars made in similar manner but without the Neodol nonionic surfactant and adipic acid. The control bars are found to have an average cracking rating of 51 compared with an average cracking rating of 0 for the bars containing nonionic surfactant and adipic acid. By comparison, in Example 2 of the above-mentioned British Patent 30 Specification No. 2,068,977 a substantially similar soap bar -9- I,I paTEMT 01**- * 0 i, JAU ivoi </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 202842 containing 2% adipic acid but no nonionic surfactant is indicated to have an average cracking rating of 3. Example 2 Example 1 in repented oubotitutUiK 2 parts of azeJaic acid for the adipic acid. These bars are likewise found to have an average cracking rating of 0. By comparison, in Example 1 of said British Specification No. 2,068,977 a substantially similar soap bar containing 3.5$ azelaic acid but no nonionic surfactant is indicated to have an average cracking rating of 1. Example 3 When Examples 1 and 2 are repeated using Neodol U5 — 13 .25 alkanol + 13 E.0.) instead of Neodol 23-6.5, substantially similar results are obtained. Example ^ When Examples 1, 2 and 3 are repeated using as the soap chips 3/1 tallow/coco sodium soap chips of 13$ moisture content, substantially similar results are obtained. This invention has been disclosed with respect to preferred embodiments thereof and it will be understood that modifications and variations thereof obvious to those skilled in the art are to be included within the spirit and purview of this application and the scope of the appended claims. 202842 WHAT WE CLAIM IS:

1. A detergent bar comprising, by weight, at least 70% of a Cg 2Q fatty acid salt, 0.5% to less than 5% of one or a mixture of hydrocarbyl or hydroxyhydrocarbyl polycarboxylic acids of 2 to 20 carbon atoms, and 1% to less than 25% of one or a mixture of ethoxameric nonionic surface active agents.

2. A detergent bar according to Claim 1 containing 1 to 3% of the polycarboxylic acid and 2 to less than 10% of the nonionic surface active agent.

3. A detergent bar according to Claim I or 2 wherein the polycarboxylic acid is an alkanedioic or hydroxya1kanedLoic acid of 2 to 10 carbon atoms.

4. A detergent bar according to Claim 1 or 2 wherein the nonionic surface active agent is the condensation product of one mole of a Cg_20 alkanol with 4 to 20 moles of ethylene oxide.

5. A detergent bar according to Claim 1 or 2 wherein the po1 year boxy 1ic acid is adipic acid or azelaic acid and the nonionic surface active agent is the condensation product of one mole of a Cjq |g alkanol with 5 to 15 mo 1 es of ethylene in Claim 5 comprising dissolving the polycarboxylic acid in the nonionic surface active agent and mixing the resulting solution with the fatty acid salt. oxide.

6. A method of preparing a detergent bar as defined in Claim 1 or 2 comprising dissolving the polycarboxylic acid in the nonionic surface active agent and mixing the resulting solution with the fatty acid salt.

7. A method of preparing a detergent bar as defined WEST-WALKER, McCABfc per: ATTORNEYS HE APPLICANT -3 MAR 1986 </div>