Field of the Invention
[0001] The present invention relates to cleaning formulations comprising water, one or more
organic solvents having low solubility in water such as aliphatic hydrocarbons, aromatic
hydrocarbons, or other organic compounds, and an alkylene glycol dilevulinate. The
alkylene glycol dilevulinates are excellent solvents for coupling the organic solvents
with water.
Background of the Invention
[0002] Organic solvents are compounds that can be used to dissolve, soften, melt, or extract
another compound, such as grease, soil, oil, paint, glue, stains, etc., and, therefore,
are commonly used in cleaning formulations. Typical organic solvents include aliphatic
hydrocarbons, isoparaffins, aromatic hydrocarbons, chlorinated hydrocarbons, terpenes
and d-limonene, among others. Unfortunately, many organic solvents have limited solubility,
or practically zero solubility, in water which severely limits the amounts that can
be added to water-based cleaning formulations sometimes to the point where their beneficial
effects cannot be realized.
[0003] Coupling agents are compounds that facilitate dissolution and dispersion of organic
solvents, into water-based formulations, in greater amounts than otherwise possible,
while the formulations retain their clarity, viscosity and homogeneity. Various coupling
agents are known for use in cleaning formulations including propylene glycol, diethylene
glycol, glycol ethers, and surfactants, among others. See
U.S. Patent Nos. 4,511,488. However, lower glycol ethers are volatile organic compounds (VOCs) which are environmentally
undesirable. Some higher glycol ethers have lesser solubility in water-based systems,
which limits their utility as coupling agents.
[0004] WO 2010/138907 discloses a solution comprises a solute dissolved in an aqueous cosolvent mixture,
where the aqueous cosolvent is a mixture that includes water and at least one alkyl
ketal ester that is miscible in water at the relative proportions of it present in
the cosolvent mixture. The preferred alkyl ketal esters are based upon levulinic acid.
Esters of levulinic acid are well known and described in the art as plasticizers and
solvents. For example,
GB423919 describes the production of esters of levulinic acid with modified polyhydric alcohols
which are useful as plasticizers for cellulose derivatives in coating applications.
[0005] For example,
U.S. Patent No. 2,654,723 describes the preparation of diethylene glycol dilevulinate by heating a mixture
of levulinic acid and diethylene glycol, in a solvent such as toluene and in the presence
of an acid catalyst.
[0006] International Patent Application No.
WO 2010/102203 describes the preparation of alkyl levulinates by an acid-catalyzed reaction of furfuryl
alcohol with other alcohols including methanol, ethanol, propanol, isopropanol, butanol,
and isobutanol.
[0007] In
U.S. Patent No. 3,203,964, a process is described for manufacturing levulinic acid esters by heating furfuryl
alcohol with another alcohol selected from the group consisting of unsubstituted primary
and secondary carbon chain and oxygen-carbon chain aliphatic and carbon ring and oxygen-carbon
ring cycloaliphatic alcohols containing from 1 to 10 carbon atoms, in the presence
of a an acid catalyst.
U.S. Patent No. 3,203,964 states that the levulinic acid esters are useful as plasticizers or solvents.
[0008] International Patent Application Publication No.
WO2007/094922 describes the use of ester derivatives of levulinic acid to replace traditional plasticizers
and coalescent solvents in polymer compositions, plastics and water-based coatings,
thereby to lowering their VOC content.
[0009] GB478854 describes the use of lower alkylene glycol dilevulinates (e.g., dilevulinates of
propylene glycol, diethylene glycol, ethylene glycol, trimethylene glycol (1,3-propanediol),
1,3-butylene glycol and dimethyl-dimethylol) as suitable high boiling softening agents
for cellulosic pellicles.
U.S. Patent No. 2,581,008 discloses the preparation of dilevulinates of mono-, di- and tri-ethoxylated diols
and their use as plasticizers for polyvinyl acetals and other polymers.
[0010] Furfuryl alcohol and levulinic acid are two of the reactants that can be used to
manufacture esters of levulinic acid, e.g., alkylene glycol dilevulinates. They are
both inexpensive renewable feedstocks available from biomass. Thus, the use of levulinates
as solvents in water-based cleaning formulations would be economically and environmentally
beneficial.
[0011] A solvent which would facilitate the use of organic solvents having low water solubility
in water-based systems, such as aqueous cleaning formulations, would provide significant
advantages relative to solvents traditionally used as coupling agents. The present
invention provides for the use of alkylene glycol dilevulinates as new alternative
coupling agent solvents in water-based formulations.
Summary of the Invention
[0012] The present invention provides a cleaning formulation comprising: (A) an aqueous
solvent comprising water; (B) an active component comprising an organic solvent; and
(C) a coupling agent comprising an alkylene glycol dilevulinate. The alkylene glycol
dilevulinate has the general formula, CH
3C(O)CH
2CH
2C(O)O-R-O(O)CCH
2CH
2C(O)CH
3, wherein R is a C
2-C
8 straight chain or branched alkylene moiety, and the two levulinate groups (CH
3C(O)CH
2CH
2C(O)O-) may be attached to adjacent, or non-adjacent, carbon atoms of the alkylene
moiety. In some embodiments, for example, R may be a C
2-C
3 alkylene moiety, and the alkylene glycol dilevulinate may be selected from the group
consisting of: ethylene glycol dilevulinate, 1,2-propylene glycol dilevulinate and
1,3-propylene glycol dilevulinate. The organic solvent may have a solubility of no
more than 10%, or no more than 5%, by weight, in water at 25ºC and atmospheric pressure,
based on the total weight of the organic solvent and water in solution. Furthermore,
the organic solvent may be at least one compound selected from the group consisting
of: an aliphatic hydrocarbon, an aromatic hydrocarbon, a chlorinated hydrocarbon,
a terpene, lemon oil, pine oil, methyl soyate and d-limonene.
[0013] In one embodiment of the cleaning formulation of the present invention, the aqueous
solvent comprising water (A) may be present in an amount of from 90% to 98% by weight,
the active component comprising an organic solvent (B) may be present in an amount
of from 0.1% to 5.0% by weight, and the coupling agent comprising an alkylene glycol
dilevulinate (C) may be present in an amount of from 0.1% to 6.0%, all weight percentages
based on the total weight of the cleaning formulation.
Brief Description of the Drawings
[0014] A more complete understanding of the present invention will be gained from the embodiments
discussed hereinafter and with reference to the accompanying figures in which:
Figure 1 is a schematic grid diagram of the general layout of sample formulations,
each containing various types of glycol ethers as coupling agents, various amounts
of d-limonene fragrance, and 1% sodium lauryl sulfate (SLS) surfactant, which were
tested for coupling effectiveness as shown in Figures 2-4;
Figures 2, 3 and 4 are diagrams in accordance with the general layout of Figure 1,
showing coupling effectiveness of the glycol ethers at 25ºC, 40ºC and 5ºC, respectively;
Figure 5 is a schematic grid diagram of the general layout of sample formulations,
each containing various types of glycol ethers as coupling agents, various amounts
of d-limonene fragrance, and 0% SLS surfactant, which were tested for coupling effectiveness
as shown in Figures 6-8;
Figures 6, 7 and 8 are diagrams in accordance with the general layout of Figure 5,
showing coupling effectiveness of the glycol ethers at 25ºC, 40ºC and 5ºC, respectively;
Figure 9 is a schematic grid diagram of the general layout of sample formulations,
each containing various types of alkylene glycol dilevulinates as coupling agents,
various amounts of d-limonene fragrance, and 1% SLS surfactant, and tested for stability
as shown in Figures 10-12;
Figures 10, 11 and 12 are diagrams in accordance with the general layout of Figure
9, showing the stability of formulations containing the alkylene glycol dilevulinates
at 25ºC, 40ºC and 5ºC, respectively;
Figure 13 is a schematic grid diagram of the general layout of sample formulations,
each containing various types of alkylene glycol dilevulinates as coupling agents,
various amounts of d-limonene fragrance, and 0% SLS surfactant, and tested for stability
as shown in Figures 14-16; and
Figures 14, 15 and 16 are diagrams in accordance with the general layout of Figure
13, showing stability of formulations containing the alkylene glycol dilevulinates
at 25ºC, 40ºC and 5ºC, respectively.
Detailed Description of the Invention
[0015] The present invention relates to the use of alkylene glycol dilevulinates or mixtures
of alkylene glycol dilevulinates in water-based cleaning formulations to couple active
components comprising organic compounds such as solvents or fragrances, having low
or zero water solubility, with water. Alkylene glycol dilevulinates can be economically
produced from levulinic acid and a glycol. Levulinic acid is available from biomass
and is, therefore, a renewable environmentally-friendly resource. Additionally, glycols
such as 1,2-propylene glycol and 1,3-propylene glycol are biorenewable and, therefore,
also environmentally-friendly materials.
[0016] Alkylene glycol dilevulinates are high boiling, clear liquids with minimal odor and
are not volatile organic compounds (VOCs). These particular characteristics provide
benefits and advantages to their use as alternative coupling agents in water-based
cleaning formulations. For example, traditional coupling agents such as propylene
glycol, diethylene glycol and lower glycol ethers are volatile organic compounds (VOCs)
which are environmentally undesirable. Also, with the exception of dipropylene glycol
methyl ether, glycol ethers are not as effective couplers as the alkylene glycol dilevulinates.
The alkylene glycol dilevulinates are partially to completely water soluble and are
not VOCs. Since it is widely understood by persons of ordinary skill in the relevant
art that diesters are typically not water soluble, the fact that alkylene glycol dilevulinates
are water soluble and, therefore, useful as coupling agents in water-based systems
is a surprising and unexpected benefit. Furthermore, applicants have discovered that
alkylene glycol dilevulinates provide better coupling performance which allows the
use of greater amounts of organic solvents having low or zero water solubility with
water, than when traditional coupling agents are used. Inclusion of greater amounts
of the organic solvents increases cleaning efficiency while maintaining preferred
formulation characteristics such as homogeneity, clarity, stability and viscosity.
[0017] It is also believed that alkylene glycol dilevulinates could be particularly useful
in aerosol products such as hair care products, sanitizers, and insecticides, and
spray applied consumer products. These dilevulinate solvents allow the formulation
of more efficient, safer and more environmentally friendly formulations and may facilitate
the development of many novel formulations suitable for cleaning, coatings, pigment
dispersants, pesticides, and agricultural applications.
[0018] As used hereinafter, the terms "an alkylene glycol dilevulinate" and "alkylene glycol
dilevulinates" are both meant to include the presence of one or more compounds having
the general formula, CH
3C(O)CH
2CH
2C(O)O-R-O(O)CCH
2CH
2C(O)CH
3, wherein R is a C
2-C
8 straight chain or branched alkylene moiety, and the two levulinate groups (CH
3C(O)CH
2CH
2C(O)O-) may be attached to adjacent, or non-adjacent, carbon atoms of the alkylene
moiety. Thus, an "alkylene glycol dilevuninate" may be one compound which satisfies
the foregoing general formula, or a mixture of such compounds. Where a mixture of
alkylene glycol dilevulinates is synthesized or otherwise available, it is not necessary
that the various species from one another before using the mixture in a cleaning formulation
in accordance with the present invention.
[0019] As also used hereinafter, the term "organic active components" is meant to include
organic materials that perform a particular function in the cleaning formulations,
such as organic solvents, fragrances, etc. "Organic solvents," as the term is used
herein, means compounds that dissolve, soften, melt, or extract another compound,
such as grease, soil, oil, paint, glue, stains, etc., and which are, therefore, commonly
used in cleaning formulations. Typical organic solvents include, without limitation,
aliphatic hydrocarbons, isoparaffins, aromatic hydrocarbons, chlorinated hydrocarbons,
and terpenes, among others. "Fragrances," as the term is used herein, means organic
compounds that impart a particular odor to the cleaning formulation, and may or may
not also provide the same function as organic solvents. Typical fragrances include,
for example, d-limonene, lemon oil and pine oil.
[0020] The term "coupling agents" as used herein means compounds that facilitate dissolution
and dispersion of organic solvents, into water-based formulations, in greater amounts
than otherwise possible, while the formulations retain their preferred characteristics
of clarity, viscosity and homogeneity. Traditional coupling agents used in cleaning
formulations include, without limitation, propylene glycol, diethylene glycol, glycol
ethers, and some surfactants, among others.
[0021] It is noted that in the following description, endpoints of ranges are considered
to be definite and are recognized to incorporate within their tolerance other values
within the knowledge of persons of ordinary skill in the art, including, but not limited
to, those which are insignificantly different from the respective endpoint as related
to this invention (in other words, endpoints are to be construed to incorporate values
"about" or "close" or "near" to each respective endpoint). The range and ratio limits,
recited herein, are combinable. For example, if ranges of 1-20 and 5-15 are recited
for a particular parameter, it is understood that ranges of 1-5, 1-15, 5-20, or 15-20
are also contemplated and encompassed thereby.
[0022] All percentages stated herein are weight percentages, unless otherwise stated.
[0023] The cleaning formulations of the present invention comprise an aqueous solvent comprising
water, an active component comprising at least one organic solvent, and at least one
alkylene glycol dilevulinate.
[0024] The aqueous solvent may comprise up to 100% water. Furthermore, cleaning formulation
may comprise the aqueous solvent comprising water in an amount between 70 and 98%
by weight, based on the total weight of the formulation. For example, the aqueous
solvent comprising water may be present in an amount between 94 and 98% by weight.
[0025] The organic active component may be an organic solvent or fragrance and may have
a solubility in water of not more than 10% by weight at 25ºC and atmospheric pressure,
or for example, not more than 5%, or even 1%, by weight at 25ºC and atmospheric pressure,
based on the total weight of the organic solvent or fragrance and water in solution.
Typical examples include, without limitation, d-limonene, lemon oil, pine oil, methyl
soyate, and terpenes.
[0026] In accordance with the present invention, the cleaning formulations may comprise
an organic active component in an amount between 0.1 to 20.0% by weight, based on
the total weight of the formulation. For example, without limitation, the organic
active component may be present in an amount between 0.5 to 3.0% by weight.
[0027] The alkylene glycol dilevulinates suitable for use in the present invention are lower
alkylene glycol dilevulinates of general formula CH
3C(O)CH
2CH
2C(O)O-R-O(O)CCH
2CH
2C(O)CH
3, derived from alkylene glycols having the general formula HO-R-OH, wherein R is a
C
2-C
8 straight chain or branched alkylene moiety, and the two hydroxyl groups may be on
adjacent carbons, for example ethylene glycol and 1,2-propylene glycol, or on non-adjacent
carbons, for example 1,3-propanediol or 1,6-hexanediol. Particularly suitable are
alkylene glycol dilevulinates of the foregoing general formula, wherein R is a C
2-C
3 alkylene, such as ethylene, 1,2-propylene, or 1,3-propylene.
[0028] In particular, applicants have found that diesters of ethylene glycol, 1,2-propylene
glycol, and 1,3-propylene glycol with levulinic acid are surprisingly good solvents
for coupling aromatic and aliphatic hydrocarbons and other organic materials with
water. Ethylene glycol dilevulinate (EGDL) is 100% water soluble while 1,2-propylene
glycol dilevulinate (1,2-PGDL) is 10% soluble by weight in water, and 1,3-propylene
glycol dilevulinate (1,3-PGDL) is 25% soluble. All three compounds also dissolve aromatic
hydrocarbon compounds such as toluene and xylene, while having limited solubility
for simple aliphatic hydrocarbons such as hexane and cyclohexane. Thus, C
2-C
3 alkylene glycol dilevulinates appear to provide the greatest benefits when used as
coupling agents in water-based cleaning formulations.
[0029] The cleaning formulations may suitably comprise the alkylene glycol dilevulinate
in an amount between 0.1 and 6.0% by weight, based on the total weight of the formulation.
For example, without limitation, the alkylene glycol dilevulinate may be present in
the cleaning formulations in an amount between 0.5 and 3.0% by weight. Processes for
preparing esters of levulinates are well known and commercially practiced. For example,
International Patent Application No.
WO 2010/102203 describes reacting furfuryl alcohol with other alcohols (e.g., methanol, ethanol,
propanol, isopropanol, butanol, and isobutanol), in equimolar amounts, in the presence
of an acid catalyst, to produce corresponding alkyl levulinates.
[0030] Alkylene glycol dilevulinates suitable for use in accordance with the cleaning formulation
of the present invention may be prepared by any process known now or in the future
and is not particularly limited. For example,
U.S. Patent No. 2,654,723 describes the preparation of diethylene glycol dilevulinate to involve mixing appropriate
amounts of levulinic acid, diethylene glycol and toluene (as the reaction solvent),
heating the mixture to react the levulinic acid and diethylene glycol and to remove
water produced by that reaction, followed by removing the toluene by stripping to
yield an amount of diethylene glycol dilevulinate, which has a boiling point above
200ºC. From this source, it is seen that production of a dilevulinate from levulinic
acid and an alkylene glycol requires providing these reactants at a molar ratio of
(levulinic acid):(alkylene glycol) of at least 2:1.
[0031] Laboratory quantities of the glycol dilevulinates may be conveniently prepared, for
instance, by the method described in the examples provided hereinbelow.
[0032] Thus, alkylene glycol dilevulinates suitable for use in the present invention include,
without limitation, those prepared from any linear or branched C
2-C
8 mono-, di-, or tri-alkylene glycol, and levulinic acid.
[0033] As with other, known cleaning formulations, cleaning formulations in accordance with
the present invention may contain ingredients in addition to water, an organic active
component and a coupling agent. For example, the cleaning formulations may also comprise
one or more surfactants, buffers, chelating agents, biocides, fragrances, viscosity
modifiers, colorants, and polymers, among other things.
[0034] Suitable surfactants, for example include, without limitation, sodium linear alkylbenzene
sulfonates, alkyl sulfates, alpha olefin sulfonates, acyl sarcosinates, sodium salt
of coconut fatty acids, sulfonated alkyl esters, alkyl polyglucosides, primary alcohol
ethoxylates, alkyl polypentasides, secondary alcohol ethoxylates, EO-PO and EO-BO
block polymers, and sodium 3-dodecylamino-propionate. Suitable buffers include, for
example, without limitation, sodium hydroxide (NaOH), alkanolamines, amines, ammonia,
alkali metal carboxylates, citric acid, sodium citrate, and lactic acid.
[0035] Suitable chelating agents, for example include, without limitation, ethylene diamine-N,N'-tetraacetic
acid, the mono-, di-, tri-, and tetra sodium salts of (EDTA), nitriloacetic acid,
trisodium salt (NTA), hydroxyl ethyl iminodiacetic acid, disodium salt (HEIDA), methyl
glycinediacetic acid, trisodium salt (MGDA), glutamic acid, N,N-diacetic acid tetrasodium
salt (GLDA), iminodiacetic acid, tetrasodium salt, (IDS), tri(hydroxymethyl)amino
methane (TRIS), 2-amino-2-ethyl 1,3-propanediol, 2-amino-2-methyl propanol, 2-amino-2-methyl-1,3-propanediol,
and polyamines.
[0036] Suitable colorants, for example include, without limitation, dyes.
[0037] Polymers suitable for use in the cleaning formulations of the present invention,
for example include, without limitation, polyacrylate homopolymers and copolymers,
METHOCELs, ETHOCELs, hydroxyethyl cellulose, POLYOXs, polyethylene glycols, polypropylene
glycols, polyvinylpyrrolidones, and polyvinyl alcohols.
[0038] The use, application and benefits of the present invention will be clarified by the
following discussion and description of exemplary embodiments and applications of
the cleaning formulations of the present invention.
EXAMPLES
Preparation of Ethylene Glycol Dilevulinate
[0039] In the laboratory, we prepared the glycol dilevulinates using an acid catalyst (Dowex
DR-2030 resin beads, a strong cation exchange resin) and the procedure described below:
Ethylene glycol (99.17 g, 1.598 moles), levulinic acid (378.4 g, 3.259 moles), and
8.08 g of Dowex DR-2030 resin beads were placed in a 1 L round-bottom flask. The flask
was attached to a Büchi Rotavapor and heated in a 95°C bath while water aspirator
vacuum was applied. Water produced by the reaction was collected in the Rotavapor
catch flask. After 14 hours, the Dowex DR-2030 beads were filtered from the orange
solution which was placed in a 500 mL round-bottom flask. A 1 foot jacketed Vigreux
column surmounted by a standard vacuum distillation head with a thermometer and water-cooled
condensing finger was attached to the flask, and distillation at about 0.5 mm Hg at
elevated temperature was begun. Six fractions were then collected at increasing distillation
temperatures. Fractions 3 to 5 ranged from 95 to 98 area % purity based on gas chromatographic
analysis, and represented an overall 67% yield based on ethylene glycol used. Identity
of the product as ethylene glycol dilevulinate was confirmed by 1H and 13C NMR spectroscopy.
[0040] 1,3-propanediol dilevulinate and 1,2-propanediol dilevulinate were prepared in a
similar manner with overall yields of 70% and 59% respectively.
Examples 1-24 - Relative Coupling Effectiveness With Fragrances
[0041] The following study was performed to evaluate the stability and coupling capabilities
of alkylene glycol dilevulinates in different formulations containing one of three
fragrances, outdoor, orange, lemon.
[0042] To speed up the preparation of cleaning formulations for testing, we created stock
solutions that contained the main components which didn't change throughout Examples
1-24, along with stock solutions with surfactant combinations. These stock solutions
were used along with the other components to formulate the samples by weight percent.
20-gram samples of each formulation were prepared.
[0043] Each formulation contained the following ingredients in the following amounts shown
in the following TABLE OF STANDARD INGREDIENTS Examples 1-24:
TABLE OF STANDARD INGREDIENTS - Examples 1-24
Name |
Amount (wt %) |
Description/Comment |
VERSENE HEIDA |
1.00 |
Chelating agent, commercially available from the Dow Chemical Company of Midland,
Michigan, U.S.A. |
|
|
An aqueous solution of disodium ethanoldiglycine which is readily biodegradable. It
is particularly useful for chelation of iron in mildly alkaline solutions |
Diisopropanolamine (DiPA) |
0.50 |
A buffer, replaces traditional monoethanolamine (MEA) buffer |
Sodium Hydroxide (NaOH) |
0.20 |
Buffer, pH adjuster |
Water |
variable |
Aqueous solvent |
Fragrance |
0.50 |
one of the following as listed in TABLE 1 |
|
|
"outdoor" |
|
|
"orange" |
|
|
"lemon" |
Coupling Agents / Solvents Tested
[0044] Each formulation contained 2.00 wt% of one of the following solvent/couplers, as
indicated in TABLE 1:
PG-Dilevulinate = 1,2-propylene glycol dilevulinate
1,3-PG-Dilevulinate = 1,3-propylene glycol dilevulinate
EG-Dilevulinate = ethylene glycol dilevulinate
DOWANOL DPnP = di-propylene glycol propyl ether (a P-series glycol ether)
[0045] After the desired formulations with the fragrances were prepared, we checked their
stability at 5°C, 20°C, and 50°C and noted if the sample was clear, hazy or cloudy.
To evaluate slight haze, we took a piece of paper with black text written on it, and
held it behind the vial containing the formulation. If we could see the black text
clearly, we noted the formulation as clear. If we could not see the text at all, we
noted the formulation as cloudy. Finally, if we could see the text, but it was not
a vibrant black, the formulation was described as hazy. The less haze or cloudiness,
the better the coupling achieved between the water and the fragrance (organic solvent)
[0046] The following TABLE 1 presents the results of testing various formulations containing
difficult-to-couple fragrances (organic active ingredients), i.e., "outdoor", "orange"
and "lemon," using the aforesaid testing procedure.
Example Set I (Comparative) & Set II (Working) - Figures 1-16
[0047] Two sets of experiments (I & II) were performed to determine the relative coupling
effectiveness of fragrance (d-limonene)-containing aqueous formulations having various
traditional coupling agents (glycol ethers) and those having various alkylene glycol
dilevulinates as the coupling agents, at various temperatures (5°C, room temperature
(25°C) and 40°C). The details are provided below and the results are shown in diagrams
provided in Figures 1-16 and explained hereinbelow.
[0048] Stock solutions were prepared that contained the main components which didn't change
throughout these experiments. Each formulation contained the following standard ingredients:
TABLE OF STANDARD INGREDIENTS - Sets I & II
Name |
Amount (wt %) |
Description/Comment |
sodium lauryl sulfate (SLS) |
none or 1% |
Surfactant |
Water |
variable |
Aqueous solvent |
D-Limonene (fragrance) |
various |
Amounts of fragrance were varied among 0.5%, 0.75%, 1.5% and 3% by weight |
[0049] More particularly, the cleaning formulations were in either:
Set I - Comparative Examples (see Figures 1-8), which included a known coupling agent
selected from one of the following glycol ethers, in an amount of 1, 5, 10 or 20 weight
percent as indicated in the figures:
BuCb = diethylene glycol n-butyl ether
BTG = triethylene glycol n-butyl ether
HxCb = diethylene glycol n-hexyl ether
ETG = triethylene glycol ethyl ether
MTG = triethylene glycol methyl ether
TPM = tripropylene glycol methyl ether
or the Set II - Working Examples (see Figures 9-16) that included an alkylene glycol
dilevulinate according to the present invention, or DOWANOL DPM, dipropylene glycol
monomethyl ether, in an amount of 1, 5, 10 or 20 weight percent, and selected from
the following compounds:
1,2 EGDL = ethylene glycol dilevulinate,
1,2-PGDL = 1,2-propylene glycol dilevulinate,
1,3-PGDL = 1,3-propylene glycol dilevulinate,
1,2 EGDL + 1,2-PGDL = 50/50 mix of 1,2-ethylene glycol dilevulinate and 1,2-propylene
glycol dilevulinate,
DPM = dipropylene glycol methyl ether.
[0050] With reference now to the figures, Figures 1-8 relate to the Set of Comparative Examples.
Each circle represents one sample formulation. More particularly, each of Figures
1 & 5 provide a schematic grid diagram of the general layout of sample formulations
having various types of glycol ethers as coupling agents and various amounts of d-limonene
fragrance, in the presence of 1% SLS surfactant and absence (0% SLS) of surfactant.
[0051] For instance, rows A & B of the grid in Figure 1 were formulations that each had
0.25% by weight d-limonene. Thus, rows A & B of each of Figures 2-4 & 6-8 depict formulations
that had 0.25% by weight d-limonene.
[0052] Columns 1 & 2 of the grid in Figure 1 were formulations that contained various amounts
of BuCb , a glycol ether, as the coupling agent. More specifically, Column 1 of the
grid in Figure 1 shows that for each vertical pair of formulations, the top formulation
had 1% by weight BuCb and the bottom one had 10% by weight BuCb. Similarly, Column
2 of the grid in Figure 1 shows that for each vertical pair of formulations, the top
formulation had 5% by weight BuCb and the bottom one had 20% by weight BuCb. This
information can be similarly translated to Columns 1 & 2 of Figures 2-4.
[0053] Thus, to provide a random example, the sample formulation at Row D, Column 6 contained
the standard ingredients listed in the TABLE above for Sets I & II, as well as 0.75%
by weight d-limonene and 20% by weight HxCb as the coupling agent, based on the total
weight of the formulation.
[0054] Figures 2-4 & 6-8 show the results (clear/white or cloudy/black) for the sample formulations
identified in the grids of Figures 1 and 5 at 5°C, room temperature (25°C), and 40°C,
respectively. Clear indicates successful coupling of the d-limonene and cloudy indicates
poor or no coupling.
[0055] Generally speaking, a review of Figures 6-8 appears to indicate that the glycol ethers
were somewhat successful at coupling d-limonene in aqueous formulations, but only
when the amount of d-limonene is relatively low, i.e., 0.25% by weight.
[0056] More specifically, sample formulation at Row D, Column 6 which contained 0.75% by
weight d-limonene and 20% by weight HxCb, was cloudy at 5°C (Figure 2), clear at room
temperature (Figure 3), and cloudy at 40°C.
[0057] Figures 9-16 relate to the Set II of Working Examples. As with Figures 1-8, each
circle represents one sample formulation. More particularly, Figure 9 provides a schematic
grid diagram of the general layout of sample formulations having various types of
alkylene glycol dilevulinates as coupling agents and various amounts of d-limonene
fragrance. For instance, rows A & B of the grid in Figure 9 were formulations that
each had 0.25% by weight d-limonene. Thus, rows A & B of each of Figures 10-12 & 14-16
depict formulations that had 0.25% by weight d-limonene.
[0058] Furthermore, Columns 1 & 2 of the grid in Figure 9 were formulations that contained
various amounts of 1,2-ethylene glycol dilevulinate (1,2-EGDL) as the coupling agent,
in accordance with the present invention. More specifically, Column 1 of the grid
in Figure 9 shows that for each vertical pair of formulations, the top formulation
had 1% by weight 1,2-EGDL and the bottom one had 10% by weight 1,2-EGDL. Similarly,
Column 2 of the grid in Figure 9 shows that for each vertical pair of formulations,
the top formulation had 5% by weight 1,2-EGDL and the bottom one had 20% by weight
1,2-EGDL. This information can be similarly translated to Columns 1 & 2 of Figures
10-12 & 14-16.
[0059] Thus, to provide a random example, the sample formulation at Row F, Column 6 contained
the standard ingredients listed in the TABLE above for Sets I & II, as well as 1.5%
by weight d-limonene and 20% by weight 1,2-EGDL as the coupling agent, based on the
total weight of the formulation.
[0060] Figures 10-12 & 14-16 show the results (clear/white or cloudy/black) for the sample
formulations identified in the grids of Figures 9 & 13 at 5°C, room temperature (25°C),
and 40°C, respectively. Clear indicates successful coupling of the d-limonene and
cloudy indicates poor or no coupling.
[0061] Generally speaking, a review of Figures 10-12 & 14-16 appears to indicate that the
alkylene glycol dilevulinates are more successful at coupling d-limonene in aqueous
formulations over a broader range of temperatures and concentrations of d-limonene
than the commonly used glycol ethers.
[0062] More specifically, sample formulation at Row F, Column 6 which contained 1.5% by
weight d-limonene and 20% by weight 1,2-EGDL, was clear at 5°C (Figure 2), clear at
room temperature (Figure 3), and cloudy at 40°C.
[0063] Figures 1-16 showed the phase stability data of glycol ethers and alkylene glycol
dilevulinates with varying levels of d-limonene in the presence of 1% SLS surfactant
and absence (0% SLS) of surfactant.
[0064] In the absence of added SLS surfactant, most of the glycol ether solvents tested
were unable to couple more than 0.25% d-limonene into an aqueous mixture. The only
exception was DOWANOL DPM. In contrast, the experimental glycol dilevulinate solvents
were fairly effective at coupling d-limonene in the absence of surfactant. Ethylene
glycol dilevulinate and 1,3-propylene glycol dilevulinate were better than 1,2-propylene
glycol dilevulinate. This is in agreement with their observed water solubility.
[0065] In the presence of 1% SLS, all of the solvents tested showed improvement in probability
to be clear. Hexyl CARBITOL, DOWANOL DPM, and the glycol dilevulinate solvents at
a 20% level were able to successfully couple even the highest d-limonene level tested,
3%.
Examples A - FF - Relative Cleaning Performance of Formulations
[0066] These experiments were intended to measure how well cleaning formulations containing
various solvent/coupling agents, as well as different combinations of surfactants,
performed in terms of leaving films or streaks, and how efficiently they cleaned.
[0067] Again, we created stock solutions that contained the main components which didn't
change throughout each set of formulations, along with stock solutions with surfactant
combinations, being either 0.5% or 1.0% total surfactant as shown in TABLE 2 below.
These stock solutions were used along with the other components to formulate the samples
by weight percent. None of these sample formulations contained any fragrance since
the goal was to see how well the cleaning formulations containing different coupling
agent and surfactant combinations cleaned. 20-gram samples of each formulation were
prepared.
[0068] Each formulation contained the following ingredients in the following amounts shown
in the following TABLE OF STANDARD INGREDIENTS Examples A-FF:
TABLE OF STANDARD INGREDIENTS - Examples A-FF
Name |
Amount (wt %) |
Description/Comment |
VERSENE HEIDA |
0.5 |
Chelating agent, commercially available from the Dow Chemical Company of Midland,
Michigan, U.S.A. An aqueous solution of disodium ethanoldiglycine which is readily
biodegradeable. It is particularly useful for chelation of iron in mildly alkaline
solutions |
Diisopropanolamine (DiPA) |
0.50 |
A buffer, replaces traditional monoethanolamine (MEA) buffer |
Sodium Hydroxide (NaOH) |
0.20 |
Buffer, pH adjuster |
Water |
variable |
Aqueous solvent |
Coupling Agents / Solvents Tested
[0069] Each formulation contained 1.00 wt% of one of the following solvent/couplers, as
indicated in TABLE 2:
PGDL = PG-Dilevulinate = 1,2-propylene glycol dilevulinate
1,3PGDL = 1,3-PG-Dilevulinate = 1,3-propylene glycol dilevulinate
EGDL = EG-Dilevulinate = ethylene glycol dilevulinate
DPnP = DOWANOL DPnP = di-propylene glycol propyl ether (a P-series glycol ether)
Surfactants and Combinations Thereof Tested
[0070] Each formulation contained a total of either 0.5% or 1.0% surfactants, as follows
and indicated in TABLE 2 below:
Different combinations of the following three eco-friendly ("green") surfactants,
but always totaling either 0.5 or 1.0 wt%, were tested among the cleaning formulations.
Each of the following surfactants is commercially available from Dow Chemical Company
of Midland, Michigan, U.S.A.:
TERGITOL 15-S-15 = a high hydrophilic-lipophilic balance emulsifier and dispersant
ECOSURF EH-6 = a water soluble nonionic surfactant
ECOSURF EH-9 = a water soluble nonionic surfactant
[0071] For some formulations, one of the following other, less environmentally-friendly
materials (both commercially available from Shell Chemical LP of Houston, Texas, U.S.A.)
was substituted for the surfactant in amounts of either 0.5 or 1.0 wt %. NEODOL 25-7
= a C
12-C
15 alcohol mixture containing an average of 7 moles of ethylene oxide per mole of alcohol.
NEODOL 45-7 = a C
14-C
15 alcohol mixture containing an average of 7 moles of ethylene oxide per mole of alcohol.
[0072] After the desired formulations with the various coupling agents and surfactant combinations
were prepared, their performance was tested with respect to cleaning efficiency (filming
and streaking) and stability (appearance at 5°C, 20°C and 60°C), as follows.
Filming and Streaking
[0073] To test the residue left by the cleaning formulation, filming and streaking tests
were done on glass tiles. Ten drops in a circular pattern were applied to a glass
tile and wiped with a folded piece of clean cheese cloth with five passes. No downward
pressure was applied on the tile, only pressure to create a back and forth motion.
The tiles were left to dry for 30 minutes. The tiles were rated on a scale of 1-10
for both filming and streaking compared to standards where WINDEX
®: Filming=1 Streaking=1 and FANTASTIK
®: Filming = 10 Streaking = 10. All tiles were rated by the same operator to minimize
discrepancies in rating and to eliminate operator to operator differences.
Hard Surface Cleaning: Spring Compression Device (SCiD)
[0074] Hard surface cleaning power of the formulations was tested by the removal of soil
from a vinyl tile. Vinyl tiles were cut to match the sample size of 11.5 cm x 7.5
cm and 500 µL of 3% Carbon Black Brazil soil was applied to the grooved side of the
tile using a foam applicator. The tiles were set to dry for approximately 24 hours,
and then the tile was placed in the SCiD plate and set on the orbital shaker. 400
µL of the cleaning solutions were dispensed into each well along with one carpeted
scrubbie, and the samples were run on the shaker for five minutes. For each sample,
3 wells were tested, and the samples were run side by side with a good and bad cleaning
standard. The samples were scanned into the computer and analyzed by the ImageJ software.
The cleaning power was measured by the average gray value of the well, and the cleaning
power of the sample was measured by the average of the gray value of the three wells.
A higher gray value corresponds to a lighter circle and a higher cleaning power, while
a lower gray value corresponds to a darker circle and a lower cleaning power.
[0075] The following TABLE 2 presents the results of testing various formulations containing
different coupling agents and surfactant combinations, using the aforesaid testing
procedure. It is noted that values for filming and streaking each run from 1 to 10,
with the lowest numbers representing the least filming or streaking and, therefore,
being the preferred values. For the "average grey" performance characteristic, the
higher values are considered more preferable.
TABLE 2
|
-----Solvent/Coupler -(%)-- |
------"Green" Surfactants---------- |
Other Surfactants--- |
|
--Cleaning Perf.----- |
-----Stability*---------- |
|
|
DPnP |
PGDL |
EGDL |
1,3-PDGL |
ECOSURF EH-6 |
ECOSURF EH-9 |
TERGITOL 15-S-15 |
NEODOL 25-7 |
NEODOL 45-7 |
Water (%) |
Filming (1-10) |
Streaking (1-10) |
60°C |
5°C |
AVG Grey Values |
A |
|
1.00 |
|
|
0.13 |
0.13 |
0.25 |
|
|
97.3 |
3 |
2 |
Clear |
Clear |
69.66 |
B |
|
1.00 |
|
|
0.25 |
0.25 |
0.50 |
|
|
96.8 |
4 |
4 |
Clear |
Clear |
93.52 |
C |
|
1.00 |
|
|
0.17 |
0.17 |
0.17 |
|
|
97.3 |
4 |
4 |
Clear |
Clear |
82.96 |
D |
|
1.00 |
|
|
0.33 |
0.33 |
0.33 |
|
|
96.8 |
5 |
5 |
Clear |
Clear |
94.82 |
E |
|
1.00 |
|
|
|
|
|
0.50 |
|
97.3 |
5 |
6 |
Cloudy |
Cloudy |
83.67 |
F |
|
1.00 |
|
|
|
|
|
1.00 |
|
96.8 |
3 |
2 |
Cloudy |
Cloudy |
91.09 |
G |
|
1.00 |
|
|
|
|
|
|
0.50 |
97.3 |
4 |
3 |
Cloudy |
Cloudy |
73.13 |
H |
|
1.00 |
|
|
|
|
|
|
1.00 |
96.8 |
5 |
5 |
Cloudy |
Cloudy |
85.96 |
I |
|
|
1.00 |
|
0.13 |
0.13 |
0.25 |
|
|
97.3 |
4 |
5 |
Clear |
Clear |
99.50 |
J |
|
|
1.00 |
|
0.25 |
0.25 |
0.50 |
|
|
96.8 |
6 |
6 |
Clear |
Clear |
126.84 |
K |
|
|
1.00 |
|
0.17 |
0.17 |
0.17 |
|
|
97.3 |
5 |
5 |
Clear |
Clear |
114.50 |
L |
|
|
1.00 |
|
0.33 |
0.33 |
0.33 |
|
|
96.8 |
6 |
6 |
Clear |
Clear |
164.02 |
M |
|
|
1.00 |
|
|
|
|
0.50 |
|
97.3 |
5 |
6 |
Cloudy |
Cloudy |
86.77 |
N |
|
|
1.00 |
|
|
|
|
1.00 |
|
96.8 |
5 |
5 |
Cloudy |
Cloudy |
115.17 |
O |
|
|
1.00 |
|
|
|
|
|
0.50 |
97.3 |
5 |
6 |
Cloudy |
Cloudy |
61.33 |
P |
|
|
1.00 |
|
|
|
|
|
1.00 |
96.8 |
6 |
6 |
Cloudy |
Cloudy |
63.716 |
Q |
|
|
|
1.00 |
0.13 |
0.13 |
0.25 |
|
|
97.3 |
5 |
5 |
Clear |
Clear |
79.37 |
R |
|
|
|
1.00 |
0.25 |
0.25 |
0.50 |
|
|
96.8 |
7 |
7 |
Clear |
Clear |
97.50 |
S |
|
|
|
1.00 |
0.17 |
0.17 |
0.17 |
|
|
97.3 |
5 |
5 |
Clear |
Clear |
84.14 |
T |
|
|
|
1.00 |
0.33 |
0.33 |
0.33 |
|
|
96.8 |
6 |
6 |
Clear |
Clear |
119.47 |
U |
|
|
|
1.00 |
|
|
|
0.50 |
|
97.3 |
6 |
6 |
Cloudy |
Cloudy |
84.88 |
V |
|
|
|
1.00 |
|
|
|
1.00 |
|
96.8 |
7 |
7 |
Cloudy |
Cloudy |
129.51 |
W |
|
|
|
1.00 |
|
|
|
|
0.50 |
97.3 |
7 |
7 |
Cloudy |
Cloudy |
60.44 |
X |
|
|
|
1.00 |
|
|
|
|
1.00 |
96.8 |
8 |
8 |
Cloudy |
Cloudy |
92.77 |
Y |
1.00 |
|
|
|
0.13 |
0.13 |
0.25 |
|
|
97.3 |
3 |
4 |
Clear |
Clear |
104.54 |
Z |
1.00 |
|
|
|
0.25 |
0.25 |
0.50 |
|
|
96.8 |
6 |
5 |
Clear |
Clear |
121.08 |
AA |
1.00 |
|
|
|
0.17 |
0.17 |
0.17 |
|
|
97.3 |
4 |
5 |
Clear |
Clear |
129.60 |
BB |
1.00 |
|
|
|
0.33 |
0.33 |
0.33 |
|
|
96.8 |
5 |
5 |
Clear |
Clear |
138.14 |
CC |
1.00 |
|
|
|
|
|
|
0.50 |
|
97.3 |
5 |
5 |
Cloudy |
Clear |
121.33 |
DD |
1.00 |
|
|
|
|
|
|
1.00 |
|
96.8 |
6 |
5 |
Cloudy |
Clear |
143.99 |
EE |
1.00 |
|
|
|
|
|
|
|
0.50 |
97.3 |
4 |
5 |
Cloudy |
Cloudy |
97.69 |
FF |
1.00 |
|
|
|
|
|
|
|
1.00 |
96.8 |
5 |
5 |
Cloudy |
Cloudy |
114.68 |
* NOTE: All formulations remained clear at 20°C |