NZ226378A - Packaged dental cream containing polyoxyethylene/polyoxypropylene block copolymer - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £26378 22 Priority Date(s): 3yC-f 9$~ Coifv'"5'8 Specification Filed: •"•••• CI»«K jfetKl/.Lk;..

Pubta-jon M, Jj.PIP.,1383 P.O. Journal, No: Patents Form No. 5 PATENTS ACT 1953 Number Dated COMPLETE SPECIFICATION PACKAGED DENTAL CREAM 28s£Pl988 We, COLGATE-PALMOLIVE COMPANY of 300 Park Avenue, New York, New York 10022, United States of America, a corporation organised under the laws of the State of Delaware, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be described in and by the following statement: ^ 22 6 37 8 This invention relates to a dental cream packaged in a plastic laminate tube, mechanical dispenser, flexible sachet or the like. In particular, it relates to a dental cream in compatible contact with a polyolefin surface of a package such as a plastic laminate dental cream tube, mechanical dispenser or flexible sachet.

Dental creams have been packaged for many years in flexible metal tubes such as wax lined lead tubes, unlined aluminum tubes or aluminum | tubes having an epoxy resin lacquer coating thereon.' In recent years, l flexible form-retaining laminated plastic tubes have been increasingly used.

Plastic laminated dental cream tubes typically comprise in inner polyolefin resin layer which is in direct contact with the dental cream and at K '' • ■ ; least one intermediate layer, including an aluminum foil layer which inhibits loss of flavor from the dental cream. Desirably, an intermediate paper layer which provides stiffness to the tube is-also present. Ihe outer layers are typically of polyolefin resins, one of which may be colored white and bear printed indicia with a clear polyolefin laminate overlay to protect the indicia. Additional intermediate laminate layers of flexible plastic may also be present.

Mechanical dental cream dispensers may also have a polyolefin surface in contact with dental cream contained therein. In fact, the polyolefin itself may be the housing of the dispenser. Flexible sachet packets may also have a polyolefin surfacein contact with dentcil cream.

Dental creams typically contain a liquid vehicle of water and humectant, a gelling agent solid vehicle and a water-insoluble dental polishing agent. A surface active is also generally included. Dental creams ccmposed of such materials wherein the humectant comprises glycerine and sorbitol and the polishing material is an alkaline earth metal salt such as © i # 226 37 8 dicalciura phosphate have been successfully packaged in flexible metal toothpaste containers including aluminum tubes which are unlined or which have an internal coating of an epoxy resin lacquer layer. However, it is observed that when such dental creams are differently packaged in containers having an interior polyolefin surface such as plastic laminated dental cream tubes, mechanically operated dental cream dispensers or flexible sachets, that syneresis becomes a problem and liquids separate frcm solids, rendering the dental cream undesirable.

In earlier ccnmonly assigned patent disclosures additives to prevent dental cream syneresis upon contact with a polyolefin surface have been disclosed for dental creams containing an alkaline earth'^vetal phosphate or > i ^alpha-alumina trihydrate polishing agent. These disclosures are: U.S. Serial No. 771,378, filed August 30, 1985, wherein the anti-syneresis additive for an alkaline earth phosphate dental cream is a polyethylene glycol? U.S. Serial No. 803,040, filed November 27, 1985, wherein the anti-syneresis additive for an alpha-alumina trihydrate dental cream is a polyethylene glycol; U.S. serial No. 808,755, filed December 13, 1985, wherein the anti-syneresis additive for a dental cream in which the polishing agent is mainly an alkaline earth metal phosphate is propylene glycol; U.S. Serial No. 922,872, filed October 31, 1986, as a continuation-in-part of, now abandoned, U.S. Serial No. 808,756, filed December 13, 1985, wherein the anti-syneresis additive for a dental cream in which the polishing agent is mainly an alkaline earth metal phosphate is an alkyl parahydroxybenzoate ester; @ % t 22 6 3 7 8 U.S. Serial No. 821,566, filed January 22, 1986, wherein the anti-syneresis additive for an alpha-alumina trihydrate dental cream is a vegetable oil; U.S. Serial No. 821,567, filed January 22, 1986, wherein the anti-syneresis additive for an alkaline earth metal phosphate dental cream is a vegetable oil; and U.S. Serial No. 835,014, filed February 28, 1986, wherein the anti-syneresis additive for a dental cream in which the polishing agent is mainly alpha-alumina trihydrate is benzoic acid.

In each of the foregoing patent disclosures condensates of ethylene oxl^e with propylene glycol, that is "Pluronic" materials, are_generally disclbsed as a type of surface-active material which may be present in the several dental creams containing the described particular anti-syneresis additives.

Japanese Public Disclosure No. 75410/85 to Ebine et al (Lion Corporation) describes a dentifrice in which glycerine is the sole humectant or mixed with another humectant, such as sorbitol, but which glycerine is, in any event, present in amount greater than 20% by weight of the dentifrice, since lesser amounts would result in undesirable evaporation of water when the dentifrice is packed in a container having a plastic container body, at least the barrel portion of which has a water permeability of at least 2 5g/m .day.50u. The high glycerine dentifrice is formulated to avoid evaporation and weight loss in this particular type of container. The disclosure includes a general indication that polymer of ethylene oxide and propylene oxide may be employed as surface-active agent.

U.S. Patent 4,556,553 to Suganuma et al (Lion Corporation) discloses dentifrices containing and aluminum oxide abrasive in a container having an \ £2 6 378 2 oxygen permeability of at least 3cc/m .day.atm wherein antiseptic properties are improved by the presence of polyhydric alcohol, including mixture of sorbitol and glycerine. There is a general disclosure that condensates of ethylene oxide with propylene oxide may be used as a surface-active agent in the aluminum oxide dentifrices. Seme dentifrice samples are described for comparative purposes which contain dicalcium phosphate with sodium lauryl sulfate as the sole surface active agent.

Japanese Public Disclosure 86526/78 to Naganuma et al (Lion Dentifrice Company) dicloses that liquid-solid separation in toothpaste containing an anionic surfactant and a polyoxyethylene block ccpolymer type surfactant (that is, a "Pluronic" surfactant) can be bverccme by employing a ^binder or gelling agent of at least one of hydroxyethyl cellulose and/or V < xanthan gum rather than carrageenan, gum tragacanth, sodium carboxymethyl cellulose, poly(sodium acrylate) or guar gum. The toothpastes described , contain a humectant such as glycerin, sorbitol, propylene glycol or polyethylene glycol. The only mixtures of humectants described in specific formulations including those which evince separation when a gelling agent other than hydroxyethyl cellulose or xanthan is employed, contain glycerine and propylene glycol.

U.S. Patent 4,353,890 to Scott (Colgate-Palmolive Company) discloses toothpastes containing carrageenan gelling agent which is stabilized by microwave radiation to maintain viscosity. A dicalcium phosphate toothpaste containing such stabilized carrageenan with a mixed humectant of 4.5% by weight of glycerol and 17.5% by weight of sorbitol is exemplified and indicated to be subjected to storage tests, including when packaged in containers having body portions of polyethylene. . The detergent or surface-active agent employed in the exemplified toothpaste is sodium lauryl sulfate. The patent includes a 22 6 3 7 8 general disclosure "Pluronics^" as detergents.

It is an advantage of this invention that phase separation of a dental cream packaged in contact with a polyolefin material which would undergo phase separation but for the presence of an additive which overcomes syneresis, is substantially prevented. Other advantages will be apparent from consideration of the following disclosure.

In accordance with certain of its aspects, this invention relates to a packaged dental cream wherein said dental cream is in direct contact with a low or medium density polyethylene or polypropylene surface, wherein syneresis occurs in said dental cream due to said direct contact when said dental cream consists essentially of as ingredients about 20-75% by weight of a liquid Vehicle consisting essentially of about 10-50% by weight of water, about 5.0-15% by weight of glycerine and sorbitol, the amount of glycerine and sorbitol together being about 15-50% by weight, the weight ratio of glycerine to sorbitol being from about 0.25:1 to about 1:1, about 0.05-10% by weight of a dental cream gelling agent selected frail the group consisting of Irish Moss, gum tragacanth, sodium carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, sodium alginate, guar gum, starch, xanthan and iota- * carrageenan, and about 20-75% by weight of a dentally acceptable water-insoluble calcium or magnesium alkaline earth metal salt polishing agent; said dental cream consisting essentially of said ingredients and as the sole additive to prevent syneresis in said dental cream upon said direct contact, about 0.1-5% by weight of a nonionic polyoxyethylene-polyoxypropylene block copolymer.

In dental cream formulations, the liquids and solids are necessarily proportioned to form a creamy mass of desired consistency which is extrudible from its package. The liquids in the present dental cream comprise chiefly © #22 6 37 8 water, glycerine and sorbitol. The total liquid vehicle amounts to about 20-75% by weight of the formulation. A gelling agent in the dental creams is a natural or synthetic gum or gumlike material, particularly, e.g. Irish Moss (carrageenan), gum tragacanth, sodium carboxymethylcellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, sodium alginate, guar gum, starch, xanthan or iota-carrageenan, including mixtures thereof. Irish Moss, sodium carboxymethyl cellulose, and iota-carrageenan, including mixtures thereof are compatible particularly and are preferred gelling agents. The gum content is in a amount of about 0.05-10% and preferably about 0.5-5% by weight of the formulation.

Water is incorporated into the dental cream in '^mount of about 1 ^0-50% by weight, preferably about 15-35%. Glycerine and sorbitol together generally conprise about 15-50% by weight, preferably about 20-35% of the dental cream, with the amount of glycerine being about 5.0-15% by weight and the weight ratio of glycerine to sorbitol being from about 0.25:1 to about 1:1, typically frctn about 0.25:1 to about 0.8:1 and preferably from about 0.25:1 to about 0.6:1. It is preferred to use about 6-10% by weight of glycerine and about 17-24% by weight of sorbitol. Amounts of sorbitol as used herein are of sorbitol syrup, as commercially available, that is 70% by weight sorbitol in 30% by weight of water.

Eentally acceptable water-insoluble alkaline earth metal salt polishing agent is present in the dental cream in amount of bout 20-75% by weight, preferably about 35-60%. Topical salts include dicalcium phosphate dihydrate, anhydrous dicalcium phosphate, calcium carbonate, tricalcium phosphate, calcium pyrophosphate, dimagnesium phosphate trihydrate and magnesium carbonate including mixtures thereof. Most preferably, calcium salt, particularly dicalcium phosphate dihydrate or mixture of dicalcium 22 63 7 8 phosphate dihydrate and anhydrous dicalcium phosphate, is present.

In addition to the alkaline earth metal salt polishing agent, additional polishing agent such as hydrated alumina and calcined alumina may be present, for instance in a weight ratio of alkaline earth metal salt to alumina material of about 2.5:1 to about 4:1, the total amount of polishing material in the dental cream being about 25-75% by weight.

The single material empLoyed in accordance with the present invention to.prevent syneresis when the dental cream is in direct contact with a low or medium density polyethylene or polypropylene is a nonionic polyoxyethylene-polyoxpropylene block copolymer. The block copolymer is also effective in the dental cream as a surface-active agent. 4"#t is present in 3 ■amount of about 0.1-5% by weight, preferably about 0.5-3%. .

",.;S * The nonionic surface-active agent employed in the instant invention is a block copolymer containing polyoxyethylene and polyoxpropylene. Such block copolymers are available frcm Wyandotte Chemicals Corporation under the trademark "Pluronic". They may be liquid, paste or solid and are generally chemically defined in terms of the moleculr weight of the polyoxypropylene hydrophobic moiety and the percent by weight of the polyoxyethylene hydrophilic moiety. The following block copolymers are available frcm Wyandotte: Pluronic Physical Mol. Wt.

Number Character Hydrophil Hydrophobe L121 Liquid 4000 L101 Liquid 3250 L 81 Liquid 2250 L 61 Liquid 1750 L 31 Liquid 950 LI 22 Liquid 4000 L 92 Liquid 2750 L 72 Liquid 2050 ' L 52 Liquid 1750 L 42 Liquid 1200 P 123 Paste 4000 P 103 Paste 3250 / L 63 Liquid 1750 £ « Liquid 1200 P-sl04 Paste 40 > 3250 P ' '94 Paste 40 2750 P 84 Paste 40 2250 P 64 Liquid 40 1750 P 44 Liquid 40 1200 P 105 Paste 50 3250 P 85 Paste 50 2250 P 75 Paste 50 2050 P 65 Paste 50 1750 P 35 Liquid 50 950 F 127 Solid 70 4000 F 87 Solid 70 2250 P 77 Solid 70 2050 F 108 Solid 80 3250 F 98 Solid 80 2750 F 88 Solid 80 2250 F 68 Solid 80 1750 F 38 Solid 80 950 22 6 3 7 8 The preferred nonionic block copolymers are solid (or flake) materials and the most preferred are Pluronic F-108 (80% polyoxyethylene: 3250 molecular weight polyoxypropylene) and F-87 (70% polyoxyethylene: 2250 molecular weight polyoxypropylene), F-127 (70% polyoxyethylene: 4000 molecular weight polyoxypropylene) and L-72 (20% polyoxyethylene: 2050 molecular weight polyoxypropylene).

Since the nonionic block copolymer anti-syneresis agent does not provide substantial foam to the dental cream, an anionic surface-active agent may also be provided for its foaming character and in order to enhance detergency. The surface-active agents may achieve increased prophylactic action, assist in achieving thorough and ccmplete dispersion of the instant ;^anpositions throughout the oral cavity and render the dental creams more '".V, cosmetically acceptable. Suitable anionic surface-active materials are water-soluble salts of higher fatty acid monoglyceride monosulfates, such as the sodium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids, higher alkyl sulfates, such as sodium lauryl sulfate, alkylaryl sulfonates, such as sodium dodecyl benzene sulfonate, olefin sulfonates, such as sodium olefin sulfonate in which the olefin group contains 12-22 carbon atans, higher alkyl sulfoacetates, higher fatty acid ester of 1,2-dihydroxy propane sulfonates, and the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acid compounds such as those having 12 to 16 carbon atcrns in the fatty acid, alkyl or acyl radicals and the like. Examples of the last mentioned amides are N-lauroyl sarcosine, and the sodium, potassium, and ethanolamine salts of N-lauroyl, N-myristoyl or N-palmitoyl sarcosine, which should be substantially free frcm soap or similar higher fatty acid material which tends to substantially-reduce the effect of these compounds in compositions of the present invention. The amides are particularly advantageous since they exhibit a prolonged and marked effect in the inhibition of acid formulation in the oral cavity due to carbohydrate breakdown in addition to exerting sane reduction in the solubility of tooth enamel in acid solutions. Another desirable material is a long chain fatty acid sodium monoglyceride sulfonate used alone or in combination with sodium * 22 6 3 7 8 lauryl sulfate. It is preferred to use about 0.2-5% by weight of total surface- active agent typically about 1-3%, when anionic surface-active agent is present.

The dental cream suitably may also contain a fluorine-containing ccmpound having a beneficial effect on the care and hygiene of the oral cavity, e.g., diminution of enamel solubility in acid and protection of the teeth against decay. Examples thereof include sodium fluoride, stanous fluoride, potassium fluoride, potassium stannous fluoride (SnF2.KF), sodium hexafluorostannate, stannous chlorofluoride, sodium fluorozirconate and sodium monofluorophosphate. These materials which disassociate or release fluorine- containing ions in water, suitably may be present in an effective but %• Ahpn-tacic amount, usually within the range of about 0.01 to 1% by weight of '" / \ t the water-soluble fluorine content thereof.

The preferred fluorine-containing compound is sodium monofluorophosphate, typically present in an amount of about 0.076 to 7.6% by weight, preferably 0.76%. A mixture of sodium monofluorophosphate and sodium fluoride is also desirable, for instance in a weight ratio of about 2:1 based on fluoride.

Any suitable flavoring or sweetening materials may be employed in formulating a flavor for the composition of the present invention. Ehcamples of suitable flavoring constituents include the flavoring oils, e.g., oils of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, cinnamon, lemon and orange, as well as methyl salicylate. Suitable sweetening agents include sucrose, lactose, maltose, xylitol, sodium 6-methyl-3, 4-dihydro-l,2,3-axathiazine-4-one, sodium cyclamate, perillartine and sodium saccharin. Suitably, flavor and sweetening agents may together comprise frcm about 0.01 to 5% or more of the compositions of the instant invention.

Various other materials may be incorporated in the dental cream. Examples thereof are coloring or whitening agents or dyestuffs, preservatives such as sodium benzoate, anti-corrosive agents, silicones, chlorophylic compounds, ammoniated materials such as urea, diairmonium phosphate and mixtures thereofand other constitutents. Whitening agents, such as titanium 2 6 3 7 8 dioxide, typically in amounts of about 0.5-2%, may be beneficial to the appearance of the dental composition, since upon aging, sane discoloration may occur.

The adjuvants are incorporated in the instant compositions in amounts which do not substantially adversely affect the properties and characteristics desired and are selected and used in proper amounts depending upon the particular type of composition involved.

Antibacterial agents may also be employed in the oral compositions of the instant invention in an amount of about 0.01-5% by weight. Typical antibacterial agents include: N1-(4-chlorobenzyl)-N^~(2,4-dichlorobenzyl) biguanide; ^ '' p-chlorophenyl biguanide; 4-chlorobenzhydryl biguanide; 4-chlorobenzhydrylguanylurea; N-3-lauroxypropyl-N -chlorobenzylbiguanide; 1,6-dichlorophenylbiguanidohexane; 1,6-bis-(2-ethylhexylbiguanido) hexane; 1- (lauryldimethylaimionium) -8- (p-chlorobenzyldimethyl-ammonium) octane dichloride; ,6-dichloro-2-guanidinobenzimidazole; N^-p-chlorophenyl-N^-laurylbiguanide; -amino-l,3-bis(2-ethylhexyl)-5-methylhexahydropyrimidine and their non-toxic acid addition salts., There may be employed also various calcium and magnesium ion suppression agents for adjustment of physical properties of the compositions. Suitable agents are the water-soluble inorganic polyphosphate salts, such as tetrasodium pyrophosphate or disodium diacid pyrophosphate, with the partially neutralized or acid polyphosphate preferred. Other suitable agents are the alkali metal, preferably sodium, salts of citric acid. In general, such compounds will be a minor amount or proportion of the formulation. The precise amount will vary depending upon the specific formulation, such as the @ 9 # 22 6 37 8 physical characteristics of the dental cream, but will usually be from about 0.1% to about 3% by weight.

The dental creams should have a pH practicable for use. A pH range of 5 to 10 is particularly desirable. The reference to the pH is meant to be the pH determination directly on the dental cream. If desired, materials such ascitric acid may be added to adjust to the pH to say 6 to 7.

The package into which the dental cream is incorporated may be any polyolefin laminate dental cream tube. For instance, the tube may be as elementary as is described in U.S. Patent 3,260,410 to Brandt et al, the disclosure of which is incorporated herein by reference. As described in the example thereof, an aluminum foil base having a thickness of about 0.0013 cm * {was heated to a temperature of approximately 177°C, and one face of the heated foil was contacted by an extrudable film of a random copolymer of ethylene and acrylic acid (acid content 3+0.5% and melt index 8+1), while the opposite surface thereof and replaced thereagainst a film of low density polyethylene. Using driven rolls, a laminated base was obtained in which the copolymer layer was about 6 mils and the polyethylene layer was approximately 5 mils in thickness. Ihe base was then shaped into tubular form and sealed. 1 After severing the tubular form into tube bodies, the tubes can be packed with the dental cream of the present invention without the dental cream undergoing syneresis.

Polyolefin laminate dentifrice tubes containing more intermediate layers may also be successfully used with the dental cream of the present invention without undergoing syneresis. For instance, the multiple layer flexible sheet structure for dental cream tubes described as "Prior Art" in U.S. Patent 4,418,841 to Eckstein may be employed as well as the more crack resistant structures described therein. The disclosure of U.S. Patent 4,418,841 to Eckstein is incoporated herein by reference. In fact, dental creams of the present invention packed in tubes of sheet material identified as Prior Art A and A-l in U.S. Patent 4,418,841 are very satisfactory and undergo substantially no syneresis. Such tubes A and A-l are comprised of layers as set forth below, in the order of outermost layer to inner most layer. o • 22 6 3 7 f ^E8r A-l 1.5 mil LDPE 2.0 mil Pigmented LDPE 1.6 mil Paper 0.7 mil LDPE 1.5 mil LDPE 2.0 mil Pigmented LDPE 1.6 mil Paper 2.0 mil LDPE 3.3 mil EAA ■■V, 0'.7 mil Foil 2.0 mil EAA 1.2 mil LDPE 1.0 mil OPP 1.0 mil EAA 0.7 mil Foil ,*4 2.0 mil EAA 13.0 mil Total 1.2 mil LDPE 13.0 mil Total In A and A-l the abbreviations have the following meanings: LDPE low density [olyethylene EAA ethylene acrylic acid OPP oriented polypropylene Medium density polyethylene may replace low density polyethylene. In a dental cream sachet package medium density polyethylene is preferred.

Mechanically operated dispensers, such as the dispenser for, in particular, pasty substances, described in U.S. Patent 4,437,591 to von Schuckmann, the disclosure of which is incorporated.herein by reference, may also be used with t^ie practice of the present invention. The housing of such dispensers is ccrrmonly canposed of a polyolefin resin such as polypropylene. ■ - - - 14 - c * 22 6 37 8 Thus the housing resin is in essence a layer, the inner surface of which is in contact with dental cream. When the dental cream of the present invention is packaged in such a polypropylene mechanical dispenser, it undergoes substantially no syneresis.

Ihe following properties are typical of low and medium density polyethylene: low Density Medium Density Polyethylene Polyethylene Clarity Transparent Transparent to to Translucent Translucent Yield ,000 (1,085,000 29,500 Sq. in/lb./0.001-in 1,065,000 sq. aVkg./0.001-cm) V :Specific gravity 0.910-0.925 0.926-0.940 Tensile strength ASTM D-882 1,000- 3,500 2,000- 5,000 lb./sg.in. (6,900-24,150 13,800-34,500 kPa.) Elongation (per cent) ASTM D-882 225 -600 225 -500 Impact Strength (kg-cm) 7-11 4-6 Tear strength ASTM D-1922 100- 400 (250-1,000 50-300 gm/0.001 in. Elmendorf 125-750 gnv/0.001 era. Elmetdorf) Heat seal range 250-350 (120-175 260-310 °F 125-155 °C) WVTR 90 per cent RH ASIM E-96 1.2 (7.74 0.5-1.0 gm/24hr/l00sq.in.@100°F 3.23-6.45^v/24hr/100sq.an. @37°C) 22 6 3 7 8 % Low Density Medium Density Polyethylene Polyethylene Gas transmission 02-ASTM D-1434 250-840 165-335 cc/0.001-in./100sq.in./ 24 hr.@ AIM 73°F+0% RH (150-515 100-205 cc/0.001cm/100sq.cm./ 24 hr.@AIM22.77c,C-K)%RH) 495-5,000 500-840 cc/0.001-in/100sg.in./ 24 hr.@ AIM 73°+0% RH Gas transmission COj-ASTM D-1434 (300-3,050 305-515 cc/0.001-ai\/100sq.cm/ 24hr.0ATM22.77°C+0%RH) Resistance to grease and oils Varies Good Maximum Use Temperature (°C) 150 (65.5 180-220 °F 82-105 °C) Minimum Use :.T^mperature (°C) ■> -60 (-51 -60 » F -51 |°C) Dimension change at high RH (per cent) None None Machine performance Fair Fair Printability Good if treated Good if treated Heat shrinkable * Seme types Seme types Typical of polypropylene grades which may be employed particularly as dispenser housing for the dental cream are those supplied by Shell Chemical Company as Polypropylene DP 5A03 and Iblypropylene DP 5A03S. These controlled rheology products combine the processibility of 12 melt flow grades with higher practical impact strength (as measured by falling weight testing). m - 22 6 3 7 8 & They were designed for fast processing in multicavity molds.

Polypropylene grades DP 5A03 and DP 5A03S have the following typical properties: Traditional ASTM Units SI Units Test Melt flow 12 g/10 min 12 g/10 min D 1238" Density at 23°C 0.905 g/cc 0.905 g/cc D 1505 Tensile yield strength, 0 at 5.0 cm/fain 5000 psi 34 MPa D 638 Yield elongation, at 5.0 cm/min 9% 9% D 638z 1% Secant modulus, o at 0.5 cm/min 190,000 psi 1300 MPa D 638 Flexural modulus, at 0.13 cm/min, 5 cm span 200,000 psi 1375 MPA ; D 79QA' Notched Ixod impact strength, at 73°F/23°C i.. o 0.5 ft-lb/in 26 J/m V D 256? •• at 0°F/-18°C 0.3 ft-lb/in J/fo D 256 hardness, Rockwell R92 R92 t> 785 He'at deflection temp., at 66 psi/455 kPA 220°F 104°C D 648 Vicat softening temp. 305°F 152°C D 1525 ^Condition 230/2.16 ASIM Type I specimen, 0.32 cm thick (injection molded) The advantages of the invention are also present when the dental cream is packed in a flexible sachet having an polyolefin surface, typically of low density or medium density polyethylene.

The following illustrative examples are further illustrative of the nature of the present invention but it is understood that the invention is not limited thereto. All amounts and proportions are by weight except as otherwise indicated.

EXAMPLE 1 The following dental creams are prepared to creamy consistencies and packed into tubes of each of laminated structures A and A-l, set forth above. 22 6 3 7 8 Parts A B Glycerine (99.3%) 10.00 10.00 Sorbitol (70%) 17.00 17.00 Sodium Carboxymethylcellulose 0.95 0.95 Sodium Saccharin 0.20 0.20 Tetrasodium Pyrophosphate 0.25 0.25 Sodium Monofluorophosphate 0.76 0.76 Dicalcium Fhosphate Dihydrate 48.76 48.76 Sodium lauryl Sulfate 1.10 ^10 flavor 0.89 0.89 Pluronic F-108 0.50 Water Q.S.to Q.S. to 100.00 100.00 Dental cream B begins to undergo syneresis and phase separation after aging for 8-10 days at rocra temperature. Dental cream A remains stable against such phase separation when aged at rocm temperature for periods , exceeding one year.

EXAMPLE 2 Dental creams (A) and (B) are incorporated into a mechanical V dispenser in accordance with U.S. Patent 4,437,591 composed of polypropylene housing. Dental cream (1) retains its creamy consistency while dentifrice (2) separates into liquid and solid phases.

Similar results to those described in the above Examples are observed when: (i) Each of Pluronic F-127 and F-87 replace Pluronic F-108; (ii) Pluronic L-72 replaces Pluronic F-108; (111) Pluronic P-84 replaces Pluronic F-108; (iv) the comparative amounts of glycerine and sorbitol (70%) are: 5:20 and 12:15; • .. - (v) Each of Irish Moss and iota-carrageenan replace - . / sodium carboxymethyl cellulose; ' - 18 - 22 6 (vi) Hie dental creams are packed in laminated tubes in accordance with U.S. Patent 3,260,410; (vii) The dental creams are packed in crack-resistant laminated tubes in accordance with U.S. Patent 4,418,841; (viii) The dental creams are packed in flexible sachets of the following structure frcm outermost to innermost layer: 12.2 u, polyethylene terephthalate 21.3 n white ethylene acrylic acid 9.0 u foil l«., ^ 3.3 u ethylene acrylic acid . .4 medium density polyethylene; and (ix) Mixture of 0.3 parts of sodium carboxymethylcellulose and 0.6 parts of iota-carrageenan replace of sodium carboxymethyl cellulose as the sole gelling material.

It is understood that the foregoing detailed description is given t merely by way of illustration and that variations may be made therein without departing frcm the spirit of the invention.

■BTO ^SF 226378'

Claims (10)

WHAT WE CLAIM IS :

1. A packaged dental cream wherein said dental cream is in direct contact with a low or medium density polyethylene or polypropylene surface, wherein syneresis occurs in said dental cream due to said direct contact when said dental cream consists essentially of as ingredients 2 0-75% by weight of a liquid vehicle consisting essentially of 10-50% by weight of water, 5.0-15% by weight of glycerine, and sorbitol, the amount of glycerine and sorbitol together being 15-50% by weight; the weight ratio of glycerine to sorbitol being frcm 0.25:1 to 1:1, 0.05-10% by weight of a dental cream gelling agent selected frcm the group consisting of Irish Moss, gum tragacanth, sodium carboxymethyl cellulose, hydroxyethyl llulose, polyvinyl pyrrolidone, sodium alginate, guar gum,( starch, xanthan water-insoluble calcium or magnesium alkaline earth metal salt polishing agent? said dental cream consisting essentially of said ingredients and as the sole additive to prevent syneresis in said dental cream upon said direct contact, 0.1-5% by weight of a nonionic polyoxyethylene-polyoxypropylene block copolymer.

2. Ihe packaged dental cream claimed in Claim 1 wherein the weight ratio of glycerine to sorbitol is frcm 0.25:1 to 0.8:1.

3. Ihe packaged dental cream claimed in Claim 1 wherein said block copolymer is a solid material.

4. Ihe packaged dental cream claimed in Claim 3 wherein said solid block copolymer has about an 80% by weight hydrophil polyoxyethylene content and a hydrophobe polyoxypropylene molecular weight of about 3250.

5. Ihe packaged dental cream claimed in Claim 1 wherein said gelling agent is sodium carboxymethyl cellulose, present in amount of 0.5-5% by weight.

6. The packaged dental cream claimed in Claim 1 wherein said water-insoluble alkaline earth metal salt is a calcium salt.

7. Ihe ,dental cream claimed in Claim 6 wherein said calcium salt dicalcium phosphate dihydrate.

8. The packaged dental cream claimed in Claim 1 wherein said . anci iota carrageenan, and 20-75% by weight of a dentally acceptable "- 20 - 6 3 7 8 dental cream is packaged in a plastic laminate tube the inner surface of which is low density.

9. The packaged dental cream claimed in claim 1 wherein said dental cream is packaged in a mechanical dispenser having a housing of polypropylene resin.

10. The packaged dental cream claimed in Claim 1 wherein said dental cream is packaged in a flexible sachet, the inner surface of which is low density polyethylene or medium density polyethylene. v ■.v A>, ' \ '• WEST-WALKER, McCABE per: ATTORNEYS F.OR THE APPLICANT