CA1237391A

CA1237391A - Prevention of vacuum collapse in flexible containers

Info

Publication number: CA1237391A
Application number: CA000471450A
Authority: CA
Inventors: Melzie L. Robinson; James C. Letton
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1984-01-06
Filing date: 1985-01-03
Publication date: 1988-05-31
Also published as: EP0150894A1; DE3562782D1; ATE34405T1; EP0150894B1

Abstract

PREVENTION OF VACUUM COLLAPSE IN
FLEXIBLE CONTAINERS
ABSTRACT OF THE DISCLOSURE
Vacuum collapse in packages containing oxygen-absorbing compositions is prevented by incorporating certain antioxidants into the compositions.

Description

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PREVEI~ll i(3N OF VACUUM COLLAPSE IN
F:LEXIBLE CONTAINERS
hlelzie L. Robinson James C. Letton TECHNiCAL FIELD OF THE IN\/ENTION
_ The present invention relates to the packaging of oxygen-absorbing compositions in flexible containers, and more par-ticularly, to jmprovements in the packaging of pine oil or other li~uid oxygen-absorbing composi$ions in flexible plastic botties.
SU~MARY OF THE INVENTION
The present invention relates to a composition in a sealed flexible container, said compositiDn containing:
A. a liquid product containing an oxygen absorbing reac-tion component in an amount sufficient to cause vacuum collapse of said container due to the absorption reaction of oxygen from container headspace, and B. a compatible antioxidant in an arnount suFficient to stabilize said oxygen absorbing component ancl thereby prevent said oxygen absorption and vacuum collapse.
Thc rnethod aspec~ of the present invention is directed to:
preventin~ vacuum collapse in flexible bottles and analogous cor)tainers containing a liquid product which comprises an oxygen absorbing reaction component in an amount sufficient to cause such vacuum col lapse, due to absorption and reaction of oxygen from container headspace, said method comprlsing adding a com-patible antioxidant in an effective amount to said lic;juid to stabili7e said oxygen absorbing component and thereby prevent said oxygen absorption and resultant vacuum collapse.
An object of the invention is to ,~rovide a novel and improved method of filling bottles, cans s: r o$her ~ypes of çon-tainers wi~h certain liquids, particul~rly with a liquid which absorbs oxygen upon contact with headspace air.
Another olbject of the invention is to provide a me$hod of filling bottles or an~logl)us containers with liquids which can be ~, 3s73~

introduced into the containers without complete expulsion of air.
A further object of the invention is to provide a method of filiing bottles or like containers with Jiquids which should be reactive with oxygen and which are to be stored in containers S consisting of a material which is unable ~o withstand atrnospheric pressure in response to a reduction of pressure in its interior to a relatively low subatmospheric pressure.
Still another object of the invention is to provide a novel method for filling relatively weak ( readily deformable) containers 10 with liquids which are normally oxygen absorbing upon contact with headspace air during storage.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates ~o the packaging of oxygen-absorbing compositions in flexible containers, and more par-15 ticlllarly to improvements in the packaging of pine oil or otherliquid oxygen-absorbing compositions in flexible plastic botties.
A flexible container îs defined herein as one which will deform (indent~ when the inside pressure is reduced to the extent ehat the pressure di fferential between the outside and the 20 inside i5 equal to or less than about 200 mm Hg under stanclard condltions. Of course, under nonstandard conditions the differ ential will vary. Many botties which are more flexible will indent when the differential is less than 150 mm Hg, and still o~hers will indent or collapse when the dif~erential is 100 ~nm Hg or less.
25 Polyvinyl chloride ( PVC~ bottles are a preferred ~ype of bottle for packaging pine oil-containing cieansers. Depending upon bottle wall thickness and/or design, a PVC bottle will coilapse when the differential is less than 200 mm Hg. In other words, if oxygen is in the headspace of the container, it is likely to react 30 wi~ he oxygen absorbing liquid and thereby collapse the bottle upon storage before or after use.
It has been observed that after flexible containers are filled with a pine oil-containing liquid or other liquid which reacts with oxygen, the flexible ~ontainer is likely to collapse in response to 35 absorption of oxygen from its interior headspace.

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The present invention is summarized above. A preferred embodiment of the present invention is when said liquid is a licluid detergent product and said oxidizable component is selected from the group consisting of: terpenes and terpenoids, and said 5 antioxidant is a soluble substituted-phenolis compound or an antioxidant which is characterized with free radical scavenging properties. The antioxidants are ef~ective when the oxidizable component is present in the liquid at a level of 40 to 400 times the weight of the antioxidant, Absorb g Liquids Containing Oxygen Reacting Components In accordance with the present invention, it has been found that liquicls which contain substantial amounts of a terpene can cause vacuum collapse in flexible containers. For the purpose of this invention, terpenoids, i . e., the oxygenatecl derivatives of 15 the terpene hydrocarbons, including the alcohols, ketones, alde-hydes, acids and esters derived from the terpenes can also be used and are to be included within the ~eneral terrn "terpene".
Useful terpenes include the acyclic, monocyclic and bicyclic terpenes. Although the C~ terpenes have becn found to be most 20 effective, sesqui-terpenes and diterpenes are also useful.
Examples of such compounds include alpha-terpenes, beta-terpenes, pheliandrene, myricene, ocimene, tricyclene, ter-pinolene, terpinoyl acetate, isoborneal, dipentene, menthol, menthone, carene, limonene, sylvestrene, sabinene, camphene, 25 alpha-farnesene, zingiberene, carylophyllene, geraniol, nerol, linalool, neral, citronellal, alpha-terpineol, 1,8-cineole, ascaridole, camphor, thujone, verbenone, fenchone, isobornyl acetate, ~arnesol, abietic acid and its salts and esters. A variety of natural1y-occurrin3 terpene mixtures, derived from various piant 30 sources, have also been found useful, fior example from pine tree oil, citrus fruits, the lemon terpenes, orange ~erpenes, lemon grass oil and lime oil distillate. Although the higher terpenes, e.g., the diterpenes and sesqui-terpenes, can ~e utilized, the terpene hydrocarbons and terpenoids, including ~he basic terpene 35 -C10 group are preferred. Generally, compositions of terpenes, 3~D~

inciuding terpenoids, are used in other compositions wi~h an antioxidant for purposes of this invention.
Oxygen reacting components are a7so found in li~uid fats and oils, such as salad oils.
The Antioxidant The substituted-phenolic antioxidant compounds useful in accordance with the present invention include any of that class of compounds which retard oxidation. They may also re$ard deteri-oration and/or rancidity.
Antioxidants include the polyphenols, such as the hydro guinones, especially the ortho- and para-polyphenols, such as pyrocatechol and pyrogallol; poly-substituted "masked" and "hindered" phenols, especially those which are substituted in the

2, 4, and 6-positions, such as 2-, 4-, 6-trialkylphenols; neutral esters of hydroxybenzoic acids, such as alkylh~fdroxybenzoic acids, p-hydroxybenzoic acid, gallic acid, and salicylic acid;
bisphenols; aminophenols; and condensed hydroxyaromatics, such as naphthols. The preferred antioxidant is 2,6-di-tert-butyl-4-methylphenol ( E~HT~ .
While not being bound to ar-y theory, it is believed that the free radical stabilization of a terpene by IBHT can be illustrated as fol lows:
ydro~ Transfer (antioxidant is oxidized) 0~1 (CH3)3c~ C(~3)3 R
J Te rpene `f Radical O~

(CH3)3c~C~Ctl3)3 + RH
Stabi I ized ~ Te rpene Ct~3 ~BHT) :~3~3~

2. Resonance Stabilization (in equilibrium) O~ O

(CH3)3c ~ C(CH3)3 ~ ______ (CH3)3~ ~ C(CH3)3 The stabilized terpene, RH, does not react with oxygen.
The free radical of the antioxidant resonates, rather than reacts with oxygen. The system is stabilized regardless of theory.
One part of an antioxidant, such as BHT, can be used to prevent vaçuum collapse in flexible containers containing liquids which have from 40 to 400 tirnes the weight of oxygen reacting/
absorbing components, such as pine oil.
~ESCRIPTION OF THE PREFERRED EhtBODIMENTS
In a preferred aspect of the present invention, it has been found that stable, built, aqueous, synthetic detergent compo-sitions containing pine oil can be formulated by utilizing suitable amounts of a pine oil compatible antioxidant free radical scavenger in the composition to stabilize the pine oil against reaction of oxyyen in the headspace of flexible containers.
A preferred liquid composition of the invention i5 an aqueous liquid detergent comprising:
(a~ from about 5% to about 1596 pine oil;
(b~ from about 0.05% to about 3% of a compatible pine oil stabilizing antioxidant, preferably 0.05~ to 1%;
(c) from about 19~ to about 10% of an anionic syn$hetic surfactan~;
(d~ from about 1% to about 20% builder selected frorn alkali metal pyrophosphates, citrates and ethyienediamine tetraacetates;
~e~ from about 1% to about 5% isopropyl alcohol;

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lf) from about 1% to about 11% of a hydrotrope selected from the group consisting of water-soluble salts of cumene, xylene and toluene suifonic acids; and ~ g ) water.
Anionic surfactants are a well-known class of surface active chemicals and any of those known in the art can be used in the present compositions.
The most common anionic surfactants can be broadly described as the water-soluble salts, par~icularly the alkali metal salts, of rganic sulfuric acid reaction products having in their molecular structure an alkyl or alkaryl radical containing from about 8 to about ~2 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acisl ester radicalsO
( I ncluded in the term "alkyl" is the alkyl pcrtion of higher acyl radicals.) Important examples of the anionic surfactants which can be employed in the practice of the present invention are the sodium or potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8-C18 carbon atoms); sodium or potassium alkyl benzene sulfonates; in which the alkyl group contains from about 9 to about 15 carbon atoms, (the alkyl radical can be a straight or branched aliphatic chain); parafFin sulfonate surfactants having the general formula RS03M, wherein R is a primary or s~condary alkyl yroup containing from about 8 to about 22 carbon atoms (preferably 10 to 18 carbon atoms) and M
is an alkali metal, e.g., sodium or potassium; sodium alkyl glyceryl ether sul~nates, especially those ethers of the higher alcohols derived from tallow and coconut oil; sodium coconut 9il fatty acicl monoglyceride sulfates and sulfonates; sodium or potassium salts of sulfuric acid esters of the reaction product of one mole of a higher fatty alcshol le.g., tallow or coconut oi!
a!cohDis1 and about 1 to about 10 moies of ethylene oxide; sodium or potassium sal~s of alkyl phenol ethylene oxicle ether sulfates with about t to about 10 units of ethylene oxide per molecule and in whsch the alkyl r~icals contain from about 8 ~o abou~ 12 c~bo~ atoms; ~he reaction products of fa~ty acids esterified with ~3~

isethionic acid and neutralizetl with sodium hydroxide where, for example, the fatty acids are derived from coconut oil; sodium or potassium salts of fatty acid amides of a methyl tauride in which the fatty acids, for example, are derived from coconut oil, and sodium or p~tasslum alpha~acetoxy or atpha-acetamido-alkane~
sulfonates where the alkane has from 8 to 22 carbon atoms.
Mixtures of anionic surfactants can also be used.
Additional anionic synthetic surfactants are disclosed in McCutcheon's Detergents and Emulsifiers, North American Ed, (1980).
Particularly preferred anlonic surfactants are the alkali metal C10-C18 alkyl sulfates and the alkali metal Cg-Cl5 linear alkyl ben~ene sulfonates, especially the C11-C13 linear alkyl benzene sulfonates .
Anionlc surfactants are generally present at levels of from about 1~ to about 105~, preferably from about 4% to about 7% in the compositions herein.
The anionic surfactant functions as a detergent material and also acts in conjunctlon with the Isopropyl alcohol to keep the plne oil solubllized in the aqueous systeril.
In addltlon to the anionic surfactants, whlch are an essentlal component of the compositlons herein, sald cornposltlons can also contaln nonionlc surfactants (e.g., the adducts of fatty alcohols or alkyl phenols wlth from 1-30 moies of ethylene oxide), amphoteric surfactants, (e.g., sodium-3-dodecylamino-propionate) andlor zwitterionic surfactants. See U.S. Pat. No. 3,664,961, Norris, issued May 23, 1972.
Sequestering bullders are used In the compositions herein at levels of from 1% to about 20~, preferably from abou~ 1% to about 30, 8%, most pteferably 5% to 8%. The sequestering builders herein are selected from the group consisting of alkali metal pyro-phosphates (e.g., K4P207) alkali metal citrates (e.g., sodium citrate) and alkali metal ethylenediamine tetraacetates (e.g., NA4EDTA, Na4H2EDTA). Alkali metal pyrophosphate is the preferred builder. This material provides alkalinity as well as sequestering water hardness ions when the composition is diluted with tap water to prepare dilute usage solutions. If EDTA or citrate is used as the sequestering builder and it is desired tha~
the composi~ion be alkaline, alkaline salts such as alkali metal carbonates, orthophosphates and silicates can be added.
Pine oil is used in the compositions herein at levels of from about 5% to about 3096, preferably from about 5% to abou~ 15%.
Pine oil is most commonly obtained by extraction or steam dis-tillation of the wood of pine ~rees. It has excellent solvent properties for greasy soils and also functions as an odorant and antimicrobial agent in the compositions herein. Pine oil is a mixture which primarily comprises terpene alcohols. The term "pine 3il~ as used herein encompasses the terpene alcohols per se, as weil as the mixture of said alcohols which naturally occurs in pine oil.
I sopropyl alcohol is present in the compositions herein at levels of from about 1~6 to about 5%, preferably from about 3% to about 5%. The isopropyl alcohQI functions along with the anionic surfactant to keep the pine oil solubilized in the aqueous system.
U.S. Pat. No. 3,360,476, Krusius, discloses glycols as solubilizers for pine oil in built, soap-based aqueous licluicl detergents. The compositions herein can be substantially free of glycols .
The water-soluble cumene, xylene or toluene sulfonate salt is present in the preferred compositions herein at levels of from about S~ to about 11%, preferably from about 7% to about 11%.
The salts which are preferred are the alkali metal salts, especiaily sodium and potassium. These sulfonate salts serve as hydro-tropes ~o keep the sequestering builders in solution in the composition .
When formulating preferred compositions herein with amounts of builder and pine oil which are a~ the high ends of ~he ranges specified herein, it is generally neeessary to use amounts of anionic surfactant, hydrotrope and isopropanol which are toward ~3~
g the high ends of the ranges stated herein for these respective ingredients, in order to secure stable compositions.
Various optional Ingredients may be included in the present compositions, These include, for example, dyes, perfumes, 5 and the like. Antimicrobial ingredtents to supplement the anti-microbial performance of pine oil are particularly preferred optlonal ingredients. These include materials such as ortho phenyl phenol, 2-benzyl-4-chlorophenol, 4-chloro-2-cyclo-pentylphenol and di-C8-C1 0 alkyldimethyl ammonium chloride .
10 These supplemental antimicrobial agents are generally used at levels of from about 0.1% to about 4% in the compositions herein.
~ Ihen 2-benzyl-4-chlorophenol is used in the compositions herein, a special solubilizer for this material is preferably also present. The solubilizer is sodium-n-decyl dlphenyloxide di-15 sulfonate ~Dowfax(~33B-2, Dow Chemical Company), and is generally used at a level whkh is about one-fourth the level of 2-benzyl-4-chlorophenol. For purposes of describing the present inven-tion, the term "anionic surfactant" shall not be understood as including sodium-n-decyl diphenyloxide disulfonate. When this 20 speclal solubilizer for 2-benzyl~4-chlorophenol is used in the composltlons hereln, Its presence Is in addition to the anionic surfactant .
The balance of the composltions herein is water. Preferably the compositions are prepared with water of low mineral content 25 such as softened or distilled water.
Although the compositions herein are inherently clear, they can be opacified with known opacifyiny agents such as latex compounds (e.g., LytronsR from Monsanto Company): micro-crystalline cellulose (e.g., AvicelR from FMC Corporation) and 30 synthetic silicates (e.g., MicrocelR from Johns-Manville Co. ) .
The invention will be further illustrated by the following examples .

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EXAMPLE I
A composit70n of tlhe present invention has the following formula ~
I ng redient Wt . _ Sodium C13 Alkaryl 5ulfonate (NaLAS) 5.2 Tetrapotassium Pyrophosphate 7 .
Pine Oil/Terpenes ~60140) 10.0 Isopropyl Alcohol 4.6 Sodiurn Cumene Sulfonate B.0 2-Benzyl-4-Chlorophenol 4.0 Sodium-n-decyl Diphenyloxide Disulfonate 1.1 Soft Water 56.8 Perfume 0 . 5 To make this composition, the following raw materials are added, in the order listed, to a 1000 ml beaker agitated by a small mechanical stirrer:
I n~ red i ent G rams Soft Watcr 306 Nal AS Solution ~40% NaLAS, 60% ~12O) 131 Tetrapotassium Pyrophosphate (65% TKPP, 35% H2O) 108 Sodium Cumene Sulfonate (1~5% NaCS, 55% H20) 239 I sopropyl Alcohol ~ I PA) 30 2-E~enzyl-4 Chlorophenol (72% active, 28~6 IPA) 56 Sodium-n-decyl Diphenyloxide Disul~onate (45% active, 55~ H2O~ 25 Pine Oil/Terpenes 100 Perfume 5 Each ingredient is allowed to agitate thoroughly prior to 35 addition o~ the nex~ ingredient. This order of addition yieids a ~3 i'~

physicaily stable, clear homogeneous composition; however, other orders of addition will suffice. Portions of the liquid composition are stored in flexible, capped 15 oz. (0.4 liter~ PVC bottles.
The bottles are fillecl to levels of about one-third to two-thirds.
5 After two months of 51torags under ambient conditions the bottles collapse (inden~). The press~re differential is about 1ûO mm Hg.
EXAMPLE I I
Same as Example 1, except that BHT is added at a level of about 0 . 8% by weight of the pine oil, which is about 0 . 08% by 10 weight of total composition. After two months storage there is no deformation or indentation of the PVC bottles.
EXAMPLE l l I
Same as Example l l, except that BI~T is added at a levei of about 1.6~6 by weight of the pine oil, which is about 0.016~6 by 15 weight of total composition. After two months storage there is no deformation or indentation of the PVC bottles.

YJHAT IS CLAIMED IS:

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An article of manufacture comprising:
A. a sealed flexible container containing, B. a liquid product containing an oxygen absorbing reaction component in an amount sufficient to cause vacuum collapse of said container due to the absorption reaction of oxygen from container headspace, and C. a compatible antioxidant in an amount suf-ficient to stabilize said oxygen absorbing component and thereby prevent said oxygen absorption and vacuum collapse.

2. The invention of claim 1 wherein said liquid is a detergent and said oxygen absorbing reaction component is selected from the group consisting of: terpenes and terpenoids, and said antioxidant is a soluble substituted-phenolic compound.

3. The invention of claim 1 wherein said contained liquid product is a stable homogeneous aqueous liquid detergent composition comprising:
(a) from about 4% to about 30% of said oxygen absorbing component which is selected from the group consisting of terpenes, terpenoids and pine oil;
(b) from about 0.05% to about 1% of said anti-oxidant which is BHT;
(c) from about 1% to about 10% of an anionic synthetic surfactant;
(d) from about 1% to about 20% builder selected from alkali metal, citrates and ethylenedi-amine tetraacetates;
(e) from about 1% to about 5% isopropyl alcohol;
(f) from about 5% to about 11% of a hydrotrope selected from the group consisting of water-soluble salts of cumene, xylene and toluene sulfonic acids; and (g) water.

4. The composition of claim 3 wherein the level of anionic surfactant is from about 4% to about 7%, the level of builder is from about 5% to about 8%, the level of pine oil is from about 10% to about 15%, and the level of anti-oxidant is from about 0.05% to about 0.5%.

5. The invention of claim 1 wherein the oxygen ab-sorbing component is pine oil and said antioxidant is BHT.

6. The invention of claim 5 wherein the level of said pine oil is present at a level of from 40 to 400 times the weight of the BHT.

7. A method of preventing vacuum collapse in flexible containers containing a liquid product which comprises an oxygen absorbing reaction component in an amount suffi-cient to cause such vacuum collapse, due to absorption and reaction of oxygen from container headspace, said method comprising adding a compatible antioxidant in an effective amount to said liquid to stabilize said oxygen absorbing component and thereby prevent said oxygen absorption and resultant vacuum collapse.