U.S. patent application number 13/809447 was filed with the patent office on 2013-05-16 for benefit delivery particle, process for preparing said particle, compositions comprising said particles and a method for treating substrates.
The applicant listed for this patent is Stuart Anthony Barnett, Craig Warren Jones, Adam John Limer, James Merrington, Jeremy Nicholas Winter. Invention is credited to Stuart Anthony Barnett, Craig Warren Jones, Adam John Limer, James Merrington, Jeremy Nicholas Winter.
Application Number | 20130122070 13/809447 |
Document ID | / |
Family ID | 42734985 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130122070 |
Kind Code |
A1 |
Barnett; Stuart Anthony ; et
al. |
May 16, 2013 |
BENEFIT DELIVERY PARTICLE, PROCESS FOR PREPARING SAID PARTICLE,
COMPOSITIONS COMPRISING SAID PARTICLES AND A METHOD FOR TREATING
SUBSTRATES
Abstract
The invention provides a benefit agent delivery particle having
an average diameter of less than 50 micron comprising; at least one
shell formed by a step-growth polymerisation reaction, preferably
involving an isocyanate monomer, more preferably a urethane and/or
a urea, interior said shell, at least one region formed by
chain-growth polymerisation reaction (preferably a free-radical
polymerisation) which does not involve an isocyanate, c)
optionally, a benefit agent interior to said shell, and/or a
deposition aid exterior to said shell. The invention further
provides a process for the preparation of such particles wherein
the shell is formed prior to the chain-growth polymerisation of the
at least one region interior of the shell, preferably be forming
the shell at a temperature at which the chain-growth reaction is
inhibited. The invention further provides fully formulated
products, preferably liquids and gels, which contain said benefit
agent delivery particles and a method of treating substrates using
said products.
Inventors: |
Barnett; Stuart Anthony;
(Bebington, GB) ; Jones; Craig Warren; (Bebington,
GB) ; Limer; Adam John; (Shanghai, CN) ;
Merrington; James; (Bebington, GB) ; Winter; Jeremy
Nicholas; (Bebington, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Barnett; Stuart Anthony
Jones; Craig Warren
Limer; Adam John
Merrington; James
Winter; Jeremy Nicholas |
Bebington
Bebington
Shanghai
Bebington
Bebington |
|
GB
GB
CN
GB
GB |
|
|
Family ID: |
42734985 |
Appl. No.: |
13/809447 |
Filed: |
July 11, 2011 |
PCT Filed: |
July 11, 2011 |
PCT NO: |
PCT/EP2011/061782 |
371 Date: |
January 10, 2013 |
Current U.S.
Class: |
424/401 ;
264/4.3; 424/493; 424/497; 424/70.11; 424/76.1; 510/349; 510/513;
510/515 |
Current CPC
Class: |
A61Q 19/10 20130101;
B01J 13/18 20130101; A61Q 13/00 20130101; A61K 8/11 20130101; C11D
17/0039 20130101; A61K 8/8152 20130101; C11D 3/505 20130101; A61K
8/87 20130101; A23L 27/72 20160801; B01J 13/16 20130101; D06M 23/12
20130101; A61Q 5/02 20130101; A61K 2800/56 20130101; D06M 23/08
20130101; A61K 2800/654 20130101; A23P 10/30 20160801; A61K
2800/413 20130101; A61K 2800/412 20130101; A61Q 15/00 20130101 |
Class at
Publication: |
424/401 ;
424/497; 510/349; 510/515; 424/493; 424/76.1; 424/70.11; 510/513;
264/4.3 |
International
Class: |
C11D 3/50 20060101
C11D003/50 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2010 |
GB |
1011905.5 |
Claims
1. A particle having an average diameter of less than 50 micron
comprising; a) at least one shell formed by a step-growth
polymerisation reaction, b) interior said shell, at least one
region formed by chain-growth polymerisation reaction which does
not involve an isocyanate, c) a benefit agent interior to said
shell and a deposition aid exterior to said shell.
2. The particle according to claim 1 wherein the step-growth
polymerisation reaction is not condensation polymerisation,
preferably involving an isocyanate monomer, preferably a urethane
and/or a urea.
3. The particle according to claim 1 wherein the chain-growth
polymerisation reaction is a radical polymerisation reaction,
preferably of at least one ethylenically unsaturated, preferably
vinyllic, monomer, preferably selected from acrylate or
methacryate.
4. The particle according to claim 1 which comprises a surface
decoration, which is a deposition aid, substantive to
proteinaceous, cellulosic, polyester or polyamide surfaces, wherein
the decoration comprises a polysaccharide.
5. The particle according to claim 1 having an average diameter of
less than 10 micron.
6. The particle according to claim 1 having an average diameter of
less than 1 micron.
7. The particle according to claim 1 comprising a hydrophobic
benefit agent, preferably an organoleptic benefit agent, preferably
a flavour or fragrance.
8. The particle according to claim 1 obtainable by a method
comprising; providing an emulsion, preferably having a mean
dispersed particle size diameter of less than 1000 nm, more
preferably less than 500 nm and having a dispersed non-aqueous
phase comprising: i) a first co-monomer, capable of step-growth
polymeriation with a suitable second co-monomer, said first
co-monomer preferably being an isocyanate; ii) an optional benefit
agent, preferably an organoleptic benefit agent; iii) at east one
monomer capable of chain-growth polymerisation; and, iv) a radical
initiator, preferably peroxide or azo-, which is not significantly
active at the temperature at which the first and second co-monomer
undergoes step-growth polymerisation, and, a continuous aqueous
phase comprising: i) water, ii) emulsifying agent, iii) a second
co-monomer, preferably a diol or diamine, preferably to form a
polyurethane or polyurea on reaction with the first co-monomer, b)
maintaining the emulsion at a temperature at which the step-growth
polymerisation occurs but not the chain growth polymerisation, and,
subsequently, c) maintaining the emulsion at a temperature at which
the chain-growth polymerisation proceeds, and d) adding a
deposition aid at the end of phase (c).
9. A The particle according to claim 8 wherein the at least one
monomer capable of chain growth polymerisation comprises an
ethylenically unsaturated, preferably vinyllic monomer, preferably
acrylate or methacryate.
10. The particle according to claim 1 which further comprises at
least one cross-linking agent, derived from: i) a more than
di-functional agent having isocyanate, alcohol, or amine
functionality, and/or ii) a more than mono-functional vinyllic
monomer,
11. A method of treatment of a substrate, wherein the substrate is
selected from skin, hair and/or textile material, the method
comprising the step of treating the substrate with a composition
comprising particles according to claim 1.
12. A composition comprising a dispersion of particles according to
claim 1, wherein the composition is a laundry detergent, laundry
conditioner, deodorant, antiperspirant, shampoo, hair conditioner
or skin care or skin cleansing product.
13. A method of preparing the composition according to claim 12 in
which the particles and the benefit agent are added separately such
that the particles take up the benefit agent in the
composition.
14. A particle having an average diameter of less than 50 micron
comprising; at least one polyurethane shell; b) interior to said
shell, a solid core formed by chain growth polymerisation of
ethylenically unsaturated species, preferably comprising acrylates
and/or methacrylates; c) a polysaccharide deposition aid exterior
to the shell, and d) a fragrance absorbed in the core.
15. The particle according to claim 14 haying a particle size of
50-500 nm.
16. (canceled)
17. (canceled)
Description
TECHNICAL FIELD
[0001] The present invention is concerned with the delivery of
particles, optionally comprising benefit agents and/or deposition
aids, to substrates, with processes for the manufacture of said
particles and the manufacture and use of formulations comprising
the same. It will be specifically described herein with reference
to laundry treatment compositions but has other and broader
applications.
BACKGROUND
[0002] Many home and personal care formulations seek to deliver
so-called benefit agents to substrates such as cloth, hair and
skin. Encapsulation of the benefit agent in particles has been
proposed as a means of enhancing delivery, which is advantageous
because of the expense of some benefit agents. Delivery of
particles per se can also be useful where the particles, even in
the absence of specific benefit agents, confer a benefit.
[0003] These particles may comprise polymers and many different
types of polymerisation are known. In the present specification a
distinction will be drawn between step-growth and chain-growth
polymerisation. This is the well-established reaction mechanism
distinction drawn by Paul Flory in 1953 (see Paul J. Flory,
"Principles of Polymer Chemistry", Cornell University Press, 1953,
p. 39. ISBN 0801401348).
[0004] For the purposes of the present specification a chain-growth
polymer is a polymer which is formed by a reaction in which
monomers bond together via rearrangement (for example, of
unsaturated and typically vinyllic bonds, or by a ring-opening
reaction) without the loss of any atom or molecule. Chain-growth
polymers grow in a single direction from one end of the chain only
and an initiator is typically used. In chain-growth polymerisation
it is commonplace that once a growth at a chain end is terminated
the end becomes unreactive.
[0005] An example of one type of chain-growth polymerisation is the
free-radical polymerisation reaction, for example the well-known
polymerization of styrene (vinyl benzene) in the presence of
benzoyl peroxide (as radical initiator) to produce polystyrene.
Similarly, aluminum chloride may be used to initiate the
polymerisation of isobutylene to form synthetic rubber. Other
examples include the polymerization reactions of acrylates or
methacryates.
[0006] A step-growth polymer is a polymer whose chain is formed
during by the reaction of poly-functional monomers to form
increasingly larger oligomers. Growth occurs throughout the matrix
and the monomer level falls rapidly in the early stages of the
reaction. No initiator is needed for a step growth polymerisation
and the ends of the growing chain generally remain active at all
times. Typically (but not always) a small molecule, which is often
water, is eliminated in the polymerization process.
[0007] An example of step-growth polymerization is the formation of
polyester by the reaction of dicarboxylic acids and glycols with
elimination of water. Another example is the polymerisation of
phenol and formaldehyde to produce "Bakelite". Other well known
step-growth polymerisation reactions are the formation of
polyesters, polyurethanes, polyureas, polyamides and
polyethers.
[0008] It should be noted that chain-growth polymerisation and
so-called "addition polymerisation" are different concepts.
Addition polymerisation is where the reaction product is a polymer
only. This may be contrasted with "condensation polymerisation"
where a small molecule (the "condensate") is also produced.
Polyurethane, for example, is produced by addition polymerisation
of (di)isocyanate compounds (R--N.dbd.C.dbd.O) with (di)hydroxy
compounds (HO--R) to form the urethane/carbamate linkage
(R--NH--CO--O--R), but the reaction mechanism is step-growth rather
than chain-growth as there is molecular rearrangement without
elimination of a small molecule.
[0009] Both chain-growth and step-growth have been used to prepare
particles by polymerisation in which some of the components are
present in the dispersed phase of an emulsion. In the case of
chain-growth, all of the components may be present in droplets of
the dispersed phase which, once initiated, react internally to form
a particle. In the case of step-growth, components may be present
both in the dispersed and the continuous phase to react at the
dispersed phase surface to form a "shell" at the interface.
[0010] In US 2009/312222 particles are prepared using so-called
"mini-emulsion" polymerisation, to give a particle with a size as
from about 30 to 500 nm. The polymer comprises units derived from
monomers that are capable of undergoing chain-growth free-radical
polymerisation. GB 2432851 discloses particles derived from
monomers that are capable of undergoing free-radical
polymerisation. GB 2432850 discloses core/shell particles in which
both the core and the shell comprises monomer units which are
derived from monomers that are capable of undergoing free-radical
polymerisation.
[0011] Emulsion polymerisation can also be performed using
step-growth reactions. U.S. Pat. No. 4,622,267 discloses an
interfacial polymerization technique for preparation of
microcapsules. US 2002/169233 discloses an interfacial
polymerization process wherein a microcapsule wall of a polyamide,
an epoxy resin, a polyurethane, a polyurea or the like is formed at
an interface between two phases. The core material is initially
dissolved in a solvent and an aliphatic diisocyanate soluble in the
solvent mixture is added. Subsequently, a non-solvent for the
aliphatic diisocyanate is added until the turbidity point is just
barely reached. This organic phase is then emulsified in an aqueous
solution, and a reactive amine is added to the aqueous phase. The
amine diffuses to the interface, where it reacts with the
diisocyanate to form polymeric polyurea shells.
[0012] Microcapsules have been proposed in which the wall material
comprises both a step-growth polymer and a chain-growth
polymer.
[0013] US 2005/0153839 disclose microcapsules for use in the
production of multicolour thermo-sensitive recording materials
having polyurethane or polyurea walls. The polymer wall includes
(via a covalent bond) a polymer obtained by radically polymerising
at least a vinyl monomer further comprising a polyether. Preferably
the raw materials for the walls are di-isocyanates. It should be
noted that the vinyl polymer is included in the wall rather than
being enclosed by it.
[0014] EP 2204155 discloses leak-proof, friable core-shell
fragrance microcapsules which have melamine-formaldehyde
(step-growth polymer) shells and in which the core may optionally
comprise, among other possibilities, high density organic
oil-soluble ingredients which may be prepared by any standard means
such as radical polymerisation of unsaturated monomers such as
vinyl or acrylic monomers (which are chain-growth polymers).
Alternatively the polymers may be prepared by condensation
reactions such as those leading to polyethers or polyesters (which
are step-growth polymers). The fragrance comprises at least one
cyclic fragrance material. The reason for including these
pre-formed high density materials is to match the density of the
micro-capsules with that of the composition in which they are used,
to prevent separation.
[0015] An effective encapsulate for a benefit agent, for example a
benefit agent such as perfume, should have the following
properties: [0016] It should have a target loading of 20% w/w
benefit agent or better and be easy to load; [0017] It should
minimise leakage of the benefit agent into a product during
manufacture and on storage; [0018] It should not require
modification of the bulk formulation, for example by requiring the
presence of structuring and/or suspending systems; [0019] Ideally,
the encapsulate should deposit well onto substrates; [0020] The
encapsulate should control the release of benefit agent.
BRIEF DESCRIPTION OF THE INVENTION
[0021] We have now determined that improved particles comprise a
shell which comprises a step-growth polymer (for example an
isocyanate based polymer) and at least one region interior to the
shell which comprises a chain-growth polymer (for example a
poly(meth)acrylate). The shell may be formed by interfacial
polymerisation, and the interior region by radical polymerisation.
Advantageously, the polymer which comprises the shell is formed
prior to the "internal" polymer.
[0022] Accordingly, the present invention provides a particle
having an average diameter of less than 50 micron comprising:
[0023] a) at least one shell formed by a step-growth polymerisation
reaction, [0024] b) interior to said shell, at least one region
formed by chain-growth polymerisation reaction which does not
involve an isocyanate, and, [0025] c) optionally, a benefit agent
interior to the shell, and/or a surface modification exterior to
said shell.
[0026] Such particles have an inner region, typically forming a
"core" which provides a sink for the benefit agent and a "shell"
which protects the benefit agent and regulates the flow of benefit
agent into and out of the core. Thus, the particle can be a carrier
which controls thermodynamic (rather than kinetic) partition of the
benefit agent between the interior region and elsewhere. This is
particularly advantageous where late-stage addition of perfume is
required as the particles and the perfume may be dosed into the
product separately.
[0027] Typically, the step-growth polymerisation reaction used to
form the shell is not a condensation polymerisation, and, more
preferably, involves an isocyanate monomer, more preferably a
urethane and/or a urea. Isocyanate monomers are reactive, enable
high monomer conversion, and form a robust, glassy shell which can
survive drying and other processing. As noted above, isocyanate
monomers react by a step-growth mechanism but are categorised as an
addition polymer by virtue of no small molecule being eliminated
during polymerisation.
[0028] Preferably, the chain-growth polymerisation reaction used to
form the inner region is a radical polymerisation reaction, more
preferably of at least one ethylenically unsaturated monomer,
conveniently a vinyllic monomer, most preferably selected from
acrylate or methacryate. Such materials enable the compatibility of
the inner region (typically a "core") and the benefit agent to be
optimised for desirable delivery parameters. In particular the
solubility parameters of the benefit agent and the chain-growth
polymer comprising the inner region may be matched to achieve
improved absorption and/or delivery.
[0029] Advantageously the particle comprises, a surface
modification, preferably a deposition aid. In particularly
preferred embodiments the deposition aid is substantive to
proteinaceous, cellulosic, polyester or polyamide surfaces. By use
of such a deposition aid, the efficiency of delivery to a specific
substrate may be enhanced.
[0030] Typically, the particle has an average diameter of less than
10 micron, and preferably an average diameter of less than 1
micron, more preferably less than 500 nm. One benefit of small
particles is that they are less visible in clear products. Another
useful benefit is that sizes below 500 nm favour deposition on
fibrous substrates and can allow formulation without the need for
suspending and/or structuring systems.
[0031] Advantageously the particle comprises a hydrophobic benefit
agent, preferably an organoleptic benefit agent, more preferably a
flavour or fragrance.
[0032] As noted above the benefit agent may be introduced into the
particle during particle formation, or may be introduced into
"empty" particles after particle formation.
[0033] Particles according to the present invention may be formed
from an emulsion by carrying out an interfacial step-growth
polymerisation first to form a shell under conditions where the
chain-growth polymerisation is inhibited. Subsequently, the
conditions are changed such that the material within the shell
undergoes the chain-growth polymerisation. A suitable change in
conditions is to increase the temperature from one at which the
chain growth reaction is inhibited to one at which it proceeds.
Other possible changes of conditions would be, for example, to use
a chain-growth reaction which is light dependent rather than
temperature dependent.
[0034] A preferred embodiment of the present invention provides a
particle obtainable by a method comprising: [0035] a) forming an
emulsion, preferably having a mean dispersed particle size diameter
of less than 1000 nm, more preferably less than 500 nm and having a
dispersed non-aqueous phase comprising: [0036] i) a first
co-monomer, preferably an isocyanate monomer, capable of
step-growth polymeriation with a suitable second co-monomer, [0037]
ii) an optional benefit agent, preferably an organoleptic benefit
agent, [0038] iii) at least one monomer, preferably acrylate or
methacryate, capable of chain-growth polymerisation, and [0039] iv)
a radical initiator, preferably peroxide or azo-, which is not
significantly active at the temperature at which the first
co-monomer undergoes step-growth polymerisation [0040] and, a
continuous aqueous phase comprising: [0041] i) water, [0042] ii) an
emulsifying agent, [0043] iii) a second co-monomer for the first
co-monomer, preferably a diol or diamine, [0044] b) maintaining the
emulsion at a temperature at which the step-growth polymerisation
occurs but not the chain growth polymerisation, and, subsequently,
[0045] c) maintaining the emulsion at a temperature at which the
chain-growth polymerisation proceeds.
[0046] Preferably the first and second co-monomers react by a
step-growth mechanism to form a poly-urethane (which may be
illustrated by the approximate formula
(--R.sub.1--NH--CO--O--R.sub.2--O--CO--NH--).sub.n) or a polyurea
(which may be illustrated by the approximate general formula
(--NH--CO--NH--R--).sub.n).
[0047] The monomer capable of chain-growth polymerisation is
preferably ethylenically unsaturated, more preferably vinyllic. In
the alternative, a ring-opening mechanism may be used.
[0048] Advantageously, the above described method provides a
potentially "one-pot" reaction which has the advantages of
simplicity and reduced losses: i.e. the shell is formed by
step-growth polymerisation at the interface of the emulsion
droplets and the core is subsequently formed within the shell by an
in-situ chain-growth polymerisation.
[0049] Conveniently the particle further comprises a cross-linking
agent, derived from a more than di-functional species having
isocyanate, alcohol, amine functionality, and/or a more than
mono-functional vinyllic monomer. Tri- and tetra functional
materials are preferred. The benefit of cross-linking agents is to
increase robustness of either the shell or the inner region, and or
decrease permeability.
[0050] Cross-linking agents in the shell, particularly the
poly-functional isocyanates, can dramatically reduce the
possibility of leakage. Cross linking agents in the inner region
can modify interaction of the "core" with the benefit agent, e.g.
by modification of the solubility parameters.
[0051] A further aspect of the invention provides a process for the
manufacture of a product comprising the particles according to the
invention wherein the particles and the benefit agent are added
separately to the formulation.
[0052] A further aspect of the present invention provides a method
of treatment of a substrate, preferably wherein the substrate is
selected from skin, hair and/or textile material, which includes
the step of treating the substrate with a composition comprising
particles according to the present invention.
[0053] Because of the robustness of the particles of the present
invention, they can be formulated in products which have relatively
harsh environments, such as high solvent content, bleaches and/or
extremes of pH. The particles are also resistant to mechanical
disruption such as may occur during product processing, transport,
storage or use, particularly on application to skin, hair or a
textile.
[0054] A yet further aspect of the present invention provides a
home or personal care composition comprising at least one particle
according to the present invention, more preferably a laundry
detergent, laundry conditioner, deodorant, antiperspirant, shampoo,
hair conditioner or skin care or skin cleansing product.
[0055] As the particles of the present invention can be small,
especially below 500 nm, they do not require suspending agents and
thereby simplify product formulation and enable the production of
clear/transparent products. Miniemulsion particles can be a small
as 50 nm.
DETAILED DESCRIPTION OF THE INVENTION
[0056] In order that the present invention may be further and
better understood it will be further described below with reference
to specific embodiments of the invention and further preferred
and/or optional features. All amounts quoted are wt. % of total
composition unless otherwise stated.
[0057] Except in the operating and comparative examples, or where
otherwise explicitly indicated, all numbers in this description
indicating amounts or ratios of material or conditions of reaction,
physical properties of materials and/or use are to be understood as
modified by the word "about".
Step Growth Polymers:
[0058] As noted above the step-growth polymer (which comprises the
"shell") is formed from monomers by the formation of increasingly
larger oligomers. Suitable classes of such monomers are found in
the group consisting of the melamine/urea/formaldehyde class, the
isocyanate/diol class (especially the polyurethanes) and
polyesters. Preferred are the melamine/urea formaldehyde class, the
isocyanate/diamine class and other classes of monomers which form
polyurethanes.
[0059] Suitable monomer compounds include: urea, thiourea,
dicyan-diamide, melem (1,3,4,6,7,9,9b-Heptaazaphenalene), melam
(N2-(4,6-diamino-1,3,5-triazin-2-yl)-1,3,5-Triazine-2,4,6-Triamine),
melon (where the heptazine is polymerized with the tri-s-triazine
units linked through an amine link), ammeline
(4,6-Diamino-2-hydroxy-1,3,5-triazine), ammelide
(6-Amino-2,4-Dihydroxy-1,3,5-Triazine), substituted melamines,
guanamines, or mixtures thereof.
[0060] Substituted melamines include the alkyl melamines and aryl
melamines which can be mono, di-, or tri-substituted. In the
alkyl-substituted melamines, each alkyl group can contain from 1 to
6 carbons, preferably from 1 to 4 carbons.
[0061] Representative examples of some alkyl-substituted melamines
are monomethylmelamine, dimethyl melamine, trimethyl melamine,
monoethyl melamine, and 1-methyl-3-propyl-5-butyl melamine.
[0062] In the aryl-substituted melamines, each aryl group can
contain 1-2 phenyl moieties and, preferably, 1 phenyl moiety.
Typical examples of an aryl-substituted melamine are monophenyl
melamine or diphenyl melamine.
[0063] Especially suitable step-growth polymers are those whose
isocyanate monomers are aromatic polyisocyanates, aliphatic
polyisocyanates, and mixtures thereof.
[0064] Suitable, aromatic polyiscocyanates comprise, but are not
limited to, 2,4-and 2,6-toluene diisocyanate, naphthalene
diisocyanate, diphenyl methane diisocyanate and triphenyl
methane-p,p'p''-trityl triisocyanate, polymethylene polyphenylene
isocyanate, 2,4,4'-diphenylether triisocyanate,
3,3'-dimethyl-4,4'-diphenyl diisocyanate, 3,3'-dimethoxy-4,4'
diphenyl diisocyanate, and 4,4'4''-triphenylmethane
triisocyanate.
[0065] Suitable aliphatic polyisocyanates comprise, but are not
limited to Dicyclohexylmethane 4,4'-diisocyanate,
hexamethylenel,6-diisocyanate, isophorone diisocyanate, trimethyl
hexamethylene diisocyanate, trimer of
hexamethylenel,6-diisocyanate, trimer of isophorone diisocyanate,
1,4-cyclohexane diisocyanate, urea of hexamethylene diisocyanate,
trimethylene diisocyanate, propylene-1,2-diisocyanate and
butylenel,2-diisocyanate and mixtures thereof.
[0066] The preferred isocyanate materials are: 2,4- and 2,6-toluene
diisocyanate and isophorone diisocyanate.
[0067] The co-monomer used in the step-growth polymerisation is
typically a diol or a diamine.
[0068] Suitable diols can comprise, but are not limited to, low
molecular weight polymers such as ethylene glycol, diethylene
glycol, propylene glycol, 1,4-butanediol, 2,3-butane diol,
neopentyl glycol, 1,6-hexanediol, dipropylene glycol, cyclohexyll,
4-dimethanol, 1,8-octanediol; high molecular weight polyols such as
polyethylene glycol, polypropylene glycols, polytetramethylene
glycols (PTMG) having average molecular weight in the range of 200
to 2000, polyester diols, diols containing carboxyl groups such as
dimethylol propionic acid (DMPA) and dimethylol butanoic acid
(DMBA) and mixtures thereof.
[0069] The preferred diol materials are ethylene glycol, diethylene
glycol, propylene glycol, 1,4butanediol, 2,3-butane diol, neopentyl
glycol, 1,6-hexanediol, and dipropylene glycol. The more
hydrophobic diols (particularly 1,4butanediol, 2,3-butane diol,
neopentyl glycol and 1,6-hexanediol) are preferred as it is
generally easier to get a stable emulsion with these materials and
thereby a more efficient polymerisation.
[0070] Suitable diamines can comprise amines such as ethylene
diamine (EDA), phenylene diamine, toluene diamine, hexamethylene
diamine, diethylenetriamine, tetraethylene pentaamine,
pentamethylene hexamine, 1,6-hexane diamine, Methylene tetramine,
2,4-diamino-6-methyl-1,3,5 triazine 1,2-diaminocyclohexane,
4,4'-diamino-diphenylmethane, 1,5-diaminonaphthalene,
2,4,4'-triaminodiphenylether, bis(hexa-methylenetriamine),
1,4,5,8-tetraminoanthraquinone, isophorone diamine, diamino propane
and diaminobutane, and mixtures thereof.
[0071] The preferred diamine materials are ethylene diamine and
1,6-hexane diamine.
[0072] Mole ratios of the co-monomers are preferably selected such
that the water soluble monomer is present in up to 10 mol % excess
over the oil soluble co-monomer, preferably 1 to 8 mol % excess,
more preferable 2 to 5 mol % excess. It is believed that this
ensures complete reaction of isocyanate monomer.
Cross-Linking Agents for Step Growth Polymerisation:
[0073] As noted above cross-linking agents advantageously improve
the properties of the shell. Many cross-linking agents suitable for
use in step-growth polymerisation are known. Cross-linking agents
significantly reduce the leakage of benefit agents from the
particles. Cross-linking agents are preferably polyamines and
polyols.
[0074] Preferred amine-functional cross-linking agents contains
more than two amine functionalities such as tetraethylene
pentamine, triethylene tetraamine, 2,4,4'-triaminodiphenylether,
bis(hexamethylene triamine), 1,4,5,8-tetramino anthraquinone and
diethylene triamine (DETA), and mixtures thereof.
[0075] Preferred alcohol-functional cross-linking agents contain
more than two alcohol functionalities such as glycerol,
pentaerythritol, and 1,1,1 trihydroxmethylpropane.
[0076] A particularly preferred cross-linking agent is
polyphenylisocyanate.
[0077] The preferred levels of cross-linking agent are 1-50 mol %,
more preferably 2-35 mol % of the step-growth monomers.
Chain Growth Polymers:
[0078] As noted above at least one region interior to the shell is
formed by chain-growth polymerisation. Typically this will comprise
a single solid region making-up the "core" of the particle.
[0079] Free-radical polymerisation (FRP) is a suitable method of
chain-growth polymerisation. In FRP a mono-functional monomer is
polymerised in the presence of free-radical initiator and,
optionally, a chain transfer agent. Chain transfer agents can act
to reduce the average molecular weight of the final polymer.
[0080] The use of a separate chain transfer agent and an initiator
is preferred. However, some molecules can perform both these
functions.
[0081] The free-radical initiator can be any molecule known to
initiate free-radical polymerisation such as azo-containing
molecules, persulfates, redox initiators, peroxides, benzyl
ketones. These initiators may be activated via thermal, photolytic
or chemical means. In the method of the present invention, thermal
activation is preferred.
[0082] Examples of suitable initiators include but are not limited
to 2,2'-azobisisobutyronitrile (AIBN), azobis(4-cyanovaleric acid),
benzoyl peroxide, cumylperoxide, 1-hydroxy-cyclohexyl phenyl
ketone, hydrogen peroxide/ascorbic acid.
[0083] So-called `iniferters` such as
benzyl-N,N-diethyldithio-carbamate can also be used.
[0084] In some cases, more than one initiator may be used.
[0085] The preferred initiators are:
2,2'-Azobis(2-methylbutyro-nitrile), 2,2'-Azobis(2.4-dimethyl
valeronitrile), 1,1'-Azobis(cyclohexane-1-carbonitrile) and t-butyl
hydro-peroxide/ascorbic acid as these minimise the production of
unwanted bi-products.
[0086] Preferably, the residue of the initiator in a free-radical
polymerisation comprises 0 to 5% w/w, preferably 0.01 to 5% w/w and
especially 0.01 to 3% w/w, of the resulting copolymer based on the
total weight of the monomers.
[0087] The chain transfer agent is preferably a thiol-containing
molecule and can be either mono-functional or multi-functional. The
agent may be hydrophilic, hydrophobic, amphiphilic, anionic,
cationic, neutral or zwitterionic. The molecule can also be an
oligomer containing a thiol moiety.
[0088] Suitable thiols include but are not limited to
C.sub.2-C.sub.18 alkyl thiols such as dodecane thiol, thioglycolic
acid, thioglycerol, cysteine and cysteamine. Thiol-containing
oligomers may also be used such as oligo(cysteine) or an oligomer
which has been post-functionalised to give a thiol group(s), such
as oligoethylene glycolyl (di)thio glycollate. Xanthates,
dithioesters, and dithiocarbonates may also be used, such as cumyl
phenyldithioacetate.
[0089] Alternative chain transfer agents may be any species known
to limit the molecular weight in a free-radical addition
polymerisation. Thus the chain-transfer agent may also be a
hindered alcohol, halocarbon, alkyl halide or a transition metal
salt or complex, or similar free-radical stabiliser. Catalytic
chain transfer agents such as those based on transition metal
complexes such as cobalt bis(borondi-fluorodimethyl-glyoximate) may
also be used.
[0090] More than one chain transfer agent may be used in
combination.
[0091] The residue of the chain transfer agent may comprise 0 to 20
mole %, preferably 0 to 10 mole % and especially 0 to 3 mole %, of
the copolymer (based on the number of moles of mono-functional
monomer). In some cases, for example in the case of some so-called
living polymerisation methods, a chain transfer agent is not
required.
[0092] Monomers for the chain-growth polymerisation may comprise
any carbon-carbon unsaturated (or cyclic) compound which can form
an addition polymer, e.g. vinyl and allyl compounds. The
mono-functional monomer may be hydrophilic, hydrophobic,
amphiphilic, anionic, cationic, neutral or zwitterionic in nature.
Thus, the mono-functional monomer may be selected from but not
limited to monomers such as vinyl acids, vinyl acid esters, vinyl
aryl compounds, vinyl acid anhydrides, vinyl amides, vinyl ethers,
vinyl amines, vinyl aryl amines, vinyl nitriles, vinyl ketones, and
derivatives of the aforementioned compounds as well as
corresponding allyl variants thereof.
[0093] Other suitable mono-functional monomers for the chain-growth
polymer include hydroxyl-containing monomers and monomers which can
be post-reacted to form hydroxyl groups, acid-containing or acid
functional monomers, zwitterionic monomers and quaternised amino
monomers.
[0094] Oligomeric or oligo-functionalised monomers may also be
used, especially oligomeric (meth)acrylic acid esters such as
mono(alk/aryl) (meth)acrylic acid esters of oligo[alkyleneglycol]
or oligo[dimethylsiloxane] or any other mono-vinyl or allyl adduct
of a low molecular weight oligomer. Mixtures of more than one
monomer may also be used.
[0095] Preferred vinyl acids and derivatives thereof include
(meth)acrylic acid and acid halides thereof such as (meth)acryloyl
chloride.
[0096] Preferred vinyl acid esters and derivatives thereof include
C1-20 alkyl(meth)acrylates (linear & branched) such as methyl
(meth)acrylate, stearyl (meth)acrylate and 2-ethyl hexyl
(meth)acrylate, aryl(meth)acrylates such as benzyl (meth)acrylate,
tri(alkyloxy)silylalkyl (meth)acrylates such as
trimethoxysilylpropyl(meth)acrylate and activated esters of
(meth)acrylic acid such as N-hydroxysuccinamido (meth)acrylate.
Vinyl aryl compounds and derivatives thereof include styrene,
acetoxystyrene, styrene sulfonic acid, vinyl pyridine, vinylbenzyl
chloride and vinyl benzoic acid. Vinyl acid anhydrides and
derivatives thereof include maleic anhydride. Vinyl amides and
derivatives thereof include (meth)acrylamide, N-vinyl pyrrolidone,
N-vinyl formamide, (meth)acrylamidopropyl trimethyl ammonium
chloride, [3-((meth)acrylamido)propyl]dimethyl ammonium chloride,
3-[N-(3-(meth) acrylamidopropyl)-N,N-dimethyl]aminopropane
sulfonate, methyl (meth) acrylamidoglycolate methyl ether and
N-isopropyl(meth)acrylamide.
[0097] Vinyl ethers and derivatives thereof include methyl vinyl
ether. Vinyl amines and derivatives thereof include
dimethylaminoethyl (meth)acrylate, diethylaminoethyl
(meth)acrylate, diisopropylaminoethyl (meth)acrylate,
mono-t-butylaminoethyl (meth)acrylate,
morpholinoethyl(meth)acrylate and monomers which can be
post-reacted to form amine groups, such as vinyl formamide. Vinyl
aryl amines and derivatives thereof include vinyl aniline, vinyl
pyridine, N-vinyl carbazole and vinyl imidazole. Vinyl nitriles and
derivatives thereof include (meth)acrylonitrile. Vinyl ketones and
derivatives thereof include acreolin.
[0098] Hydroxyl-containing monomers include vinyl hydroxyl monomers
such as hydroxyethyl (meth)acrylate, hydroxy propyl (meth)acrylate,
glycerol mono(meth)acrylate and sugar mono(meth)acrylates such as
glucose mono(meth)acrylate. Monomers which can be post-reacted to
form hydroxyl groups include vinyl acetate, acetoxystyrene and
glycidyl (meth)acrylate. Acid-containing or acid functional
monomers include (meth)acrylic acid, styrene sulfonic acid, vinyl
phosphonic acid, vinyl benzoic acid, maleic acid, fumaric acid,
itaconic acid, 2-(meth)acrylamido 2-ethyl propanesulfonic acid,
mono-2-((meth)acryloyloxy)ethyl succinate and ammonium sulfatoethyl
(meth)acrylate. Zwitterionic monomers include (meth)acryloyl
oxyethylphosphoryl choline and betaines, such as
[2-((meth)acryloyloxy)ethyl] dimethyl-(3-sulfopropyl)ammonium
hydroxide. Quaternised amino monomers include
(meth)acryloyloxyethyltri-(alk/aryl)ammonium halides such as
(meth)acryloyloxyethyltrimethyl ammonium chloride.
[0099] Oligomeric (or polymeric) monomers include oligomeric
(meth)acrylic acid esters such as
mono(alk/aryl)oxyoligo-alkyleneoxide(meth)acrylates and
mono(alk/aryl)o xyoligo-dimethyl-siloxane(meth)acrylates. These
esters include monomethoxy oligo(ethyleneglycol)
mono(meth)acrylate, monomethoxy oligo(propyleneglycol)
mono(meth)acrylate, monohydroxy oligo(ethyleneglycol)
mono(meth)acrylate and monohydroxy oligo(propyleneglycol)
mono(meth)acrylate.
[0100] Further examples include vinyl or allyl esters, amides or
ethers of pre-formed oligomers formed via ring-opening
polymerisation such as oligo(caprolactam) or oligo-(caprolactone),
or oligomers formed via a living polymerisation technique such as
oligo(1,4-butadiene). The polymeric monomers are the same, save
that the oligomers are polymers.
[0101] Macromonomers are generally formed by linking a
polymerisable moiety, such as a vinyl or allyl group, to a
pre-formed monofunctional polymer via a suitable linking unit such
as an ester, an amide or an ether. Examples of suitable polymers
include mono functional poly(alkylene oxide) such as
monomethoxy[poly(ethyleneoxide) or monomethoxy
[poly-(propyleneoxide), silicones such as poly(dimethylsiloxane),
polymers formed by ring-opening polymerisation such as
poly(caprolactone) or poly(caprolactam) or mono-functional polymers
formed via living polymerisation such as poly(1,4-butadiene).
[0102] Preferred macromonomers include
monomethoxy[poly-(ethyleneglycol)] mono (methacrylate),
monomethoxy[poly-(propyleneglycol)] mono(methacrylate), poly
(dimethylsiloxane) monomethacrylate.
[0103] The corresponding allyl monomers to those listed above can
also be used where appropriate.
[0104] More preferred monomers include: amide-containing monomers
such as (meth)acrylamide, N,N'-dimethyl(meth)acrylamide, N and or
N'-di(alkyl or aryl) (meth)acrylamide, N-vinyl pyrollidone,
(meth)acrylamidopropyl trimethyl ammonium chloride,
[3-(methacroylamino) propyl]dimethyl ammonium chloride,
3-[N-(3-methacrylamido-propyl)-N,N-dimethyl]-aminopropane
sulfonate, 4-(2-acrylamido-2-methylpropyl-dimethylammonio)
butanoate, methyl acrylamidoglycolate methyl ether and
N-isopropyl-(meth)acrylamide; (meth)acrylic acid derivatives such
as (meth)acrylic acid, (meth)acryoloyl chloride (or any halide),
(alkyl/aryl) (meth)acrylate, oligo-functionalised monomers such as
monomethoxy poly(ethyleneglycol) monomethacrylate or monomethoxy
poly(propyleneglycol) mono(meth)acrylate, glycerol
mono(meth)acrylate, glycidyl (meth)acrylate and sugar
mono(meth)acrylates such as glucose mono(meth)acrylate; vinyl
amines such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl
(meth)acrylate, t-butylamino (meth)acrylate,
morpholinoethylmethacrylate, or vinyl aryl amines such as vinyl
aniline, vinyl pyridine, N-vinyl carbazole, vinyl imidazole; vinyl
aryl monomers such as styrene, vinyl benzyl chloride, vinyl
toluene, .alpha.-methyl styrene, styrene sulfonic acid and vinyl
benzoic acid; vinyl hydroxyl monomers such as hydroxyethyl
(meth)acrylate, hydroxy propyl (meth)acrylate, glyceryl
(meth)acrylate or monomers which can be post-functionalised into
hydroxyl groups such as vinyl acetate or acetoxy styrene can also
be used; acid-containing monomers such as (meth)acrylic acid,
styrene sulfonic acid, vinyl phosphonic, maleic acid, fumaric acid,
itaconic acid, 2-acrylamido 2-ethyl propanesulfonic acid and
mono-2-(methacryloyloxy)ethyll succinate. Or aryl/alkyl esters
thereof. Or carboxylic anhydride containing monomers such as maleic
anhydride; zwitterionic monomers such as
(meth)acryloyloxyethyl-phosphoryl choline, quaternised amino
monomers such as methacryloyl-oxyethyltrimethyl ammonium
chloride.
[0105] The corresponding allyl monomer, where applicable, can also
be use in each case.
[0106] Hydrophobic monomers include: vinyl aryl compounds such as
styrene and vinylbenzyl chloride; (meth)acrylic acid esters such as
mono-t-butylaminoethyl (meth)acrylate, C1-20 alkyl(meth)acrylates
(linear & branched), aryl(meth) acrylates such as benzyl
methacrylate; oligomeric (meth)acrylic acid esters such as
mono(alk/aryl)oxyoligo-[dimethylsiloxane (meth)acrylate] and
tri(alkyloxy)-silylalkyl (meth)acrylates such as
trimethoxysilylpropyl-(meth)acrylate.
[0107] Functional monomers, i.e. monomers with reactive pendant
groups which can be post or pre-modified with another moiety can
also be used such as glycidyl (meth)acrylate,
trimethoxysilylpropyl(meth)acrylate, (meth)acryloyl chloride,
maleic anhydride, hydroxyalkyl (meth)acrylates, (meth)acrylic acid,
vinylbenzyl chloride, activated esters of (meth)acrylic acid such
as N-hydroxysuccinamido (meth)acrylate and acetoxystyrene.
[0108] The copolymer may contain unreacted polymerisable groups
from the multifunctional monomer.
[0109] Especially preferred monomers for chain growth
polymerisation are: C.sub.1-C.sub.20 linear or branched, alkyl,
alkaryl or aryl acrylates and methacrylates.
Ratio of Step-Growth to Chain Growth Polymer:
[0110] The weight fraction of step growth polymer in the combined
step growth and chain growth polymers comprising the particle is
typically 10% to 99%, preferably 15% to 80%, more preferably 25% to
75%.
Cross-Linking Agents for Chain-Growth Polymerisation:
[0111] Cross-linking agents can be used to modify the properties of
the chain-growth polymer. Suitable materials comprise a molecule
containing at least two vinyl groups that may be polymerised. The
molecule may be hydrophilic, hydrophobic, amphiphilic, neutral,
cationic, zwitterionic or oligomeric. Examples include di- or
multivinyl esters, di- or multivinyl amides, di- or multivinyl aryl
compounds and di- or multivinyl alk/aryl ethers. Typically, in the
case of oligomeric or multifunctional branching agents, a linking
reaction is used to attach a polymerisable moiety to a di- or
multifunctional oligomer or a di- or multifunctional group. The
brancher may itself have more than one branching point, such as
`T`-shaped divinylic oligomers. In some cases, more than one
multifunctional monomer may be used.
[0112] Macro cross-linkers or macro branchers (multifunctional
monomers typically having a molecular weight of at least 1000
Daltons) are generally formed by linking a polymerisable moiety,
such as a vinyl or aryl group, to a pre-formed multifunctional
polymer via a suitable linking unit such as an ester, an amide or
an ether. Examples of suitable polymers include di-functional
poly(alkylene oxides) such as poly(ethyleneglycol) or
poly(propylene glycol), silicones such as poly(dimethyl-siloxane)s,
polymers formed by ring-opening polymerisation such as
poly(caprolactone) or poly(caprolactam) or poly-functional polymers
formed via living polymerisation such as poly(1,4-butadiene).
[0113] Preferred macro branchers include poly(ethyleneglycol)
di(meth)acrylate, poly(propyleneglycol) di(meth)acrylate,
(meth)acryloxypropyl-terminated poly (dimethylsiloxane),
poly(caprolactone) di(meth)acrylate and poly(caprolactam)
di(meth)acrylamide.
[0114] The corresponding allyl monomers to those listed above can
also be used where appropriate.
[0115] Preferred multifunctional monomers include but are not
limited to divinyl aryl monomers such as divinyl benzene;
(meth)acrylate diesters such as glycerol di(meth)acrylate, ethylene
glycol di(meth)acrylate, propyleneglycol di(meth)acrylate and
1,3-butylenedi(meth)acrylate; oligoalkylene oxide di(meth)acrylates
such as tetra ethyleneglycol di(meth)acrylate,
oligo(ethyleneglycol) di(meth)acrylate and oligo(propyleneglycol)
di(meth)-acrylate; divinyl acrylamides such as methylene
bis-acrylamide; silicone-containing divinyl esters or amides such
as (meth)acryloxypropyl-terminated oligo (dimethyl-siloxane);
divinyl ethers such as oligo (ethyleneglycol)-divinyl ether; and
tetra- or tri-(meth)acrylate esters such as pentaerythritol
tetra-(meth)acrylate, trimethylolpropane tri(meth)acrylate or
glucose di- to penta(meth)acrylate. Further examples include vinyl
or allyl esters, amides or ethers of pre-formed oligomers formed
via ring-opening polymerisation such as oligo(caprolactam) or
oligo-(caprolactone), or oligomers formed via a living
polymerisation technique such as oligo(1,4-butadiene).
[0116] Especially preferred cross-linkers are divinyl benzene,
ethylene glycol di(meth)acrylate and trimethylolpropane
tri(meth)acrylate.
[0117] Levels of cross-linker are typically 0-75, preferably 0.0001
to 50, more preferably 0.0001 to 25 mol %.
Benefit Agents:
[0118] Various benefit agents can be incorporated into the
particles. Where the end use of the particles is in connection with
a surfactant-containing system, any compatible benefit agent which
can provide a benefit to a substrate which is treated with a
surfactant composition can be used. Preferred benefit agents are in
the laundry field, for example fabric benefit agents, and benefit
agents which provide a benefit to a laundry wash and/or rinse
medium. In the alternative benefit agents may provide a skin or
hair related benefit. Advantages of the particles of the invention
in the presence of surfactant are a good retention of the benefit
agent on storage of a formulation and controllable release of the
benefit agent during and after product usage.
[0119] Preferred examples include flavours and fragrances, enzymes,
antifoams, fluorescer, shading dyes and/or pigments, conditioning
agents (for example water-insoluble quaternary ammonium materials
and/or silicones), sunscreens, ceramides, antioxidants, reducing
agents, sequestrants, colour care additives, density matching
polymers, photo-bleaches, lubricants, unsaturated oils,
emollients/moisturizer and antimicrobial agents.
[0120] Preferred antimicrobials include Triclosan.TM., climbazole,
octapyrox, ketoconizole, zinc pyrithione, and quaternary ammonium
compounds.
[0121] Preferred sunscreens and/or skin lightening agents are
vitamin B3 compounds. Suitable vitamin B3 compounds are selected
from niacin, niacinamide, nicotinyl alcohol, or derivatives or
salts thereof. Other vitamins which act as skin lightening agents
can be advantageously included in the skin lightening composition
to provide for additional skin lightening effects. These include
vitamin B6, vitamin C, vitamin A or their precursors. Mixtures of
the vitamins can also be employed in the composition of the
invention. An especially preferred additional vitamin is vitamin
B6. Other non-limiting examples of skin lightening agents useful
herein include adapalene, aloe extract, ammonium lactate, arbutin,
azelaic acid, butyl hydroxy anisole, butyl hydroxy toluene, citrate
esters, deoxyarbutin, 1,3 diphenyl propane derivatives, 2, 5 di
hydroxyl benzoic acid and its derivatives, 2-(4-acetoxyphenyl)-1,3
d itha ne, 2-(4-Hydroxylphenyl)-1,3 dithane, ellagic acid, gluco
pyranosyl-1-ascorbate, gluconic acid, glycolic acid, green tea
extract, 4-Hydroxy-5-methyl-3[2H]-furanone, hydroquinone, 4
hydroxyanisole and its derivatives, 4-hydroxy benzoic acid
derivatives, hydroxycaprylic acid, inositol ascorbate, kojic acid,
lactic acid, lemon extract, linoleic acid, magnesium ascorbyl
phosphate, 5-octanoyl salicylic acid, 2,4 resorcinol derivatives,
3,5 resorcinol derivatives, salicylic acid, 3,4,5 trihydroxybenzyl
derivatives, and mixtures thereof. Preferred sunscreens useful in
the present invention are 2-ethylhexyl-p methoxycinnamate, butyl
methoxy dibenzoylmethane, 2-hydroxy-4methoxybenzophenone, octyl
dimethyl-p-aminobenzoic acid and mixtures thereof. Particularly
preferred sunscreen is chosen from 2-ethyl
hexyl-p-methoxycinnamate, 4, t-butyl-4'-methoxydibenzoyl-methane or
mixtures thereof. Other conventional sunscreen agents that are
suitable for use in the skin lightening composition of the
invention include 2-hydroxy-4-methoxybenzophenone, octyldimethyl
p-aminobenzoic acid, digalloyltrioleate,
2,2-dihydroxy-4methoxybenzophenone, ethyl-4-(bis(hydroxypropyl))
aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate,
2-ethylhexylsalicylate, glyceryl p-aminobenzoate,
3,3,5-trimethylcyclohexyl-salicylate, methylanthranilate,
p-dimethyl-aminobenzoic acid or aminobenzoate,
2-ethylhexyl-p-dimethyl amino-benzoate,
2-phenylbenzimidazole-5sulfonic acid, 2-(p
dimethylaminophenyl)-5-sulfonic benzoxazoic acid and mixtures of
these compounds.
[0122] Preferred anti-oxidants include vitamin E, retinol,
antioxiants based on hydroxytoluene such as Irganox.TM. or
commercially available antioxidants such as the Trollox.TM.
series.
[0123] Perfume and fragrance materials (which include
pro-fragrances) are a particularly preferred benefit agent.
[0124] The pro-fragrance can, for example, be a food lipid. Food
lipids typically contain structural units with pronounced
hydrophobicity. The majority of lipids are derived from fatty
acids. In these `acyl` lipids the fatty acids are predominantly
present as esters and include mono-, di-, triacyl glycerols,
phospholipids, glycolipids, diol lipids, waxes, sterol esters and
tocopherols. In their natural state, plant lipids comprise
antioxidants to prevent their oxidation. While these may be at
least in part removed during the isolation of oils from plants some
antioxidants may remain. These antioxidants can be pro-fragrances.
In particular, the carotenoids and related compounds including
vitamin A, retinol, retinal, retinoic acid and provitamin A are
capable of being converted into fragrant species including the
ionones, damascones and damscenones. Preferred pro-fragrance food
lipids include olive oil, palm oil, canola oil, squalene, sunflower
seed oil, wheat germ oil, almond oil, coconut oil, grape seed oil,
rapeseed oil, castor oil, corn oil, cottonseed oil, safflower oil,
groundnut oil, poppy seed oil, palm kernel oil, rice bran oil,
sesame oil, soybean oil, pumpkin seed oil, jojoba oil and mustard
seed oil. Perfume components which are odiferous materials are
described in further detail below.
[0125] The perfume is typically present in an amount of from 10-85%
by total weight of the particle, preferably from 15 to 75% by total
weight of the particle. The perfume suitably has a molecular weight
of from 50 to 500Dalton. Pro-fragrances can be of higher molecular
weight, being typically 1-10 kD.
[0126] Useful components of the perfume include materials of both
natural and synthetic origin. They include single compounds and
mixtures. Specific examples of such components may be found in the
current literature, e.g., in Fenaroli's Handbook of Flavour
Ingredients, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M.
B. Jacobs, edited by Van Nostrand; or Perfume and Flavour Chemicals
by S. Arctander 1969, Montclair, N.J. (USA). These substances are
well known to the person skilled in the art of perfuming,
flavouring, and/or aromatizing consumer products, i.e., of
imparting an odour and/or a flavour or taste to a consumer product
traditionally perfumed or flavoured, or of modifying the odour
and/or taste of said consumer product.
[0127] By perfume in this context is not only meant a fully
formulated product fragrance, but also selected components of that
fragrance, particularly those which are prone to loss, such as the
so-called `top notes`.
[0128] Top notes are defined by Poucher (Journal of the Society of
Cosmetic Chemists 6(2):80 [1955]). Examples of well known top-notes
include citrus oils, linalool, linalyl acetate, lavender,
dihydromyrcenol, rose oxide and cis-3-hexanol. Top notes typically
comprise 15-25% wt of a perfume composition and in those
embodiments of the invention which contain an increased level of
top-notes it is envisaged at that least 20% wt would be present
within the particle.
[0129] Typical perfume components which it is advantageous to
employ in the embodiments of the present invention include those
with a relatively low boiling point, preferably those with a
boiling point of less than 300, preferably 100-250 Celsius.
[0130] It is also advantageous to encapsulate perfume components
which have a low LogP (i.e. those which will be partitioned into
water), preferably with a LogP of less than 3.0. These materials,
of relatively low boiling point and relatively low LogP have been
called the "delayed blooming" perfume ingredients and include the
following materials:
[0131] Allyl Caproate, Amyl Acetate, Amyl Propionate, Anisic
Aldehyde, Anisole, Benzaldehyde, Benzyl Acetate, Benzyl Acetone,
Benzyl Alcohol, Benzyl Formate, Benzyl Iso Valerate, Benzyl
Propionate, Beta Gamma Hexenol, Camphor Gum, Laevo-Carvone,
d-Carvone, Cinnamic Alcohol, Cinamyl Formate, Cis-Jasmone,
cis-3-Hexenyl Acetate, Cuminic Alcohol, Cyclal C, Dimethyl Benzyl
Carbinol, Dimethyl Benzyl Carbinol Acetate, Ethyl Acetate, Ethyl
Aceto Acetate, Ethyl Amyl Ketone, Ethyl Benzoate, Ethyl Butyrate,
Ethyl Hexyl Ketone, Ethyl Phenyl Acetate, Eucalyptol, Eugenol,
Fenchyl Acetate, Flor Acetate (tricyclo Decenyl Acetate), Frutene
(tricycico Decenyl Propionate), Geraniol, Hexenol, Hexenyl Acetate,
Hexyl Acetate, Hexyl Formate, Hydratropic Alcohol,
Hydroxycitronellal, Indone, Isoamyl Alcohol, Iso Menthone,
Isopulegyl Acetate, Isoquinolone, Ligustral, Linalool, Linalool
Oxide, Linalyl Formate, Menthone, Menthyl Acetphenone, Methyl Amyl
Ketone, Methyl Anthranilate, Methyl Benzoate, Methyl Benzyl
Acetate, Methyl Eugenol, Methyl Heptenone, Methyl Heptine
Carbonate, Methyl Heptyl Ketone, Methyl Hexyl Ketone, Methyl Phenyl
Carbinyl Acetate, Methyl Salicylate, Methyl-N-Methyl Anthranilate,
Nerol, Octalactone, Octyl Alcohol, p-Cresol, p-Cresol Methyl Ether,
p-Methoxy Acetophenone, p-Methyl Acetophenone, Phenoxy Ethanol,
Phenyl Acetaldehyde, Phenyl Ethyl Acetate, Phenyl Ethyl Alcohol,
Phenyl Ethyl Dimethyl Carbinol, Prenyl Acetate, Propyl Bornate,
Pulegone, Rose Oxide, Safrole, 4-Terpinenol, Alpha-Terpinenol,
and/or Viridine
[0132] It is commonplace for a plurality of perfume components to
be present in a formulation. In the encapsulates of the present
invention it is envisaged that there will be four or more,
preferably five or more, more preferably six or more or even seven
or more different perfume components from the list given of delayed
blooming perfumes given above present in the particles.
[0133] Another group of perfumes with which the present invention
can be applied are the so-called `aromatherapy` materials. These
include many components also used in perfumery, including
components of essential oils such as Clary Sage, Eucalyptus,
Geranium, Lavender, Mace Extract, Neroli, Nutmeg, Spearmint, Sweet
Violet Leaf and Valerian. By means of the present invention these
materials can be transferred to textile articles that will be worn
or otherwise come into contact with the human body (such as
handkerchiefs and bed linen).
Surface Modifications and Deposition Aids:
[0134] Surface modifications, including deposition aids modify the
properties of the exterior of the particle. One particular benefit
which can be obtained with these materials is to make the particle
more substantive to a desired substrate. Desired substrates include
cellulosics (including cotton), polyesters (including those
employed in the manufacture of polyester fabrics) and
protein-containing substrates (such as akin and hair). Deposition
aids are preferably selected from non-hydrolysable
cotton-substantive polymers, hydrolysable cotton-substantive
polymers and polyester-substantive polymers.
[0135] Preferred polysaccharide polymers, whether hydrolysable or
not may be derived from a broad range of polysaccharides.
Preferably, the polysaccharide is selected from the group
consisting of: tamarind gum (preferably consisting of xyloglucan
polymers), guar gum, locust bean gum (preferably consisting of
galactomannan polymers), and other industrial gums and polymers,
which include, but are not limited to, Tara, Fenugreek, Aloe, Chia,
Flaxseed, Psyllium seed, quince seed, xanthan, gellan, welan,
rhamsan, dextran, curdlan, pullulan, scleroglucan, schizophyllan,
chitin, hydroxyalkyl cellulose, arabinan (preferably from sugar
beets), de branched arabinan (preferably from sugar beets),
arabinoxylan (preferably from rye and wheat flour), galactan
(preferably from lupin and potatoes), pectic galactan (preferably
from potatoes), galactomannan (preferably from carob, and including
both low and high viscosities), glucomannan, lichenan (preferably
from icelandic moss), mannan (preferably from ivory nuts),
pachyman, rhamnogalacturonan, acacia gum, agar, alginates,
carrageenan, chitosan, clavan, hyaluronic acid, heparin, inulin,
cellodextrins, cellulose, cellulose derivatives and mixtures
thereof.
[0136] Preferred non-hydrolysable cotton-substantive deposition
aids include non-hydrolysable polysaccharides. The polysaccharide
preferably has a .beta.-1,4-linked backbone.
[0137] Preferably the polysaccharide is a cellulose, a cellulose
derivative, or another .beta.-1,4-linked polysaccharide having an
affinity for cellulose, such as polymannan, polyglucan,
polyglucomannan, polyxyloglucan and polygalactomannan or a mixture
thereof. More preferably, the polysaccharide is selected from the
group consisting of polyxyloglucan and polygalactomannan. Most
preferably, the deposition aid is locust bean gum, xyloglucan, guar
gum or mixtures thereof.
[0138] Preferred hydrolysable cotton-substantive deposition aids
include hydrolysable polysaccharides. These comprise a
polysaccharide which has been modified to render it more water
soluble by means of a group covalently attached to the
polysaccharide by means of hydrolysable bond. Preferred groups may
for example be independently selected from one or more of acetate,
propanoate, trifluoroacetate, 2-(2-hydroxy-1-oxopropoxy)
propanoate, lactate, glycolate, pyruvate, crotonate, isovalerate
cinnamate, formate, salicylate, carbamate, methylcarbamate,
benzoate, gluconate, methanesulphonate, toluene, sulphonate, groups
and hemiester groups of fumaric, malonic, itaconic, oxalic, maleic,
succinic, tartaric, aspartic, glutamic, and malic acids.
[0139] Preferred amongst such hydrolysable deposition aids is
cellulose mono acetate.
[0140] Suitable and preferred polyester-substantive deposition aids
include phthalate containing polymers, more preferably a polymer
having one or more nonionic hydrophilic components comprising
oxyethylene, polyoxyethylene, oxypropylene or polyoxypropylene
segments, and, one or more hydrophobic components comprising
terephthalate segments. Typically, oxyalkylene segments of these
deposition aids will have a degree of polymerization of from 1 to
about 400, although higher levels can be used, preferably from 100
to about 350, more preferably from 200 to about 300.
[0141] One type of preferred deposition aid is a copolymer having
random blocks of ethylene terephthalate and polyethylene oxide
terephthalate.
[0142] Another preferred polymeric deposition aid is polyester with
repeat units of ethylene terephthalate units contains 10-15% by
weight of ethylene terephthalate units together with 90-80% by
weight of polyoxyethylene terephthalate units, derived from a
polyethylene glycol of average molecular weight 0.2 kD-40 kD.
Examples of this class of polymer include the commercially
available material ZELCON 5126 (from DuPont) and MILEASE T (from
101). Examples of related polymers can be found in U.S. Pat. No.
4,702,857.
[0143] Another preferred polymeric deposition aid is a sulfonated
product of a substantially linear ester oligomer comprised of an
oligomeric ester backbone of terephthaloyl and oxyalkyleneoxy
repeat units and terminal moieties covalently attached to the
backbone. These soil release agents are described fully in U.S.
Pat. No. 4,968,451. Other suitable polymeric soil release agents
include the terephthalate polyesters of U.S. Pat. No. 4,711,730,
the anionic end-capped oligomeric esters of U.S. Pat. No.
4,721,580, and the block polyester oligomeric compounds of U.S.
Pat. No. 4,702,857.
[0144] Preferred polymeric deposition aids also include the soil
release agents of U.S. Pat. No. 4,877,896 which discloses anionic,
especially sulfoarolyl, end-capped terephthalate esters.
[0145] Still another preferred deposition aid is an oligomer with
repeat units of terephthaloyl units, sulfoisoterephthaloyl units,
oxyethyleneoxy and oxy-1,2-propylene units. The repeat units form
the backbone of the oligomer and are preferably terminated with
modified isethionate end-caps. A particularly preferred deposition
aid of this type comprises about one sulfoisophthaloyl unit, 5
terephthaloyl units, oxyethyleneoxy and oxy-1,2-propyleneoxy units
in a ratio of from about 1.7 to about 1.8, and two end-cap units of
sodium 2-(2-hydroxyethoxy)-ethanesulfonate. Said soil release agent
also comprises from about 0.5% to about 20%, by weight of the
oligomer, of a crystalline-reducing stabilizer, preferably selected
from the group consisting of xylene sulfonate, cumene sulfonate,
toluene sulfonate, and mixtures thereof.
[0146] The deposition aid may be straight or branched. The
preferred molecular weight of the polymeric deposition aid is in
the range of from about 5 kD to about 500 kD, preferably 10 kD-500
kD, more preferably 20 kD-300 kD.
[0147] Preferably, the deposition-aid polymer is present at levels
such that the ratio polymer:particle solids is in the range
1:500-3:1, preferably 1:200-1:3.
Preparation Methods
[0148] Polymerisation occurs in at least two phases. In an earlier
of these phases a shell is formed by a step-growth polymerisation.
This shell encloses and contains the reagents for the chain-growth
reaction which occurs in a later phase.
[0149] Temporal separation of these phases is accomplished by
control of the reagents present and the reaction conditions.
[0150] Typically, at least one of the components of the
shell-forming reaction is withheld from the initial reaction
mixture and added gradually to control the progress of the reaction
in the first phase.
[0151] Advantageously, the first phase of the reaction is performed
under conditions in which the chain-growth reaction is inhibited.
These conditions include a sufficiently low temperature (for a
thermally activated reaction) or conditions of sufficiently low
light (for a photo-activated reaction).
[0152] Once the shell-forming reaction has proceeded sufficiently,
the conditions are modified (for example, by raising the
temperature or exposing the reaction mixture to light) to cause the
reaction to form the inner region to start.
[0153] The preferred method is one in which an emulsion is formed
comprising the chain-growth polymer components in a non-aqueous
dispersed phase and the step-growth polymer components are at the
interface between the dispersed phase and the continuous aqueous
phase.
[0154] Typically the aqueous phase comprises an emulsifying agent,
and one of the co-monomers for the step-growth polymer. It may also
contain any diol, alcohol or amine cross-linking agent.
[0155] The disperse phase comprises the chain-growth monomer, the
initiator, any isocyanate or vinyl cross-linking agents, the other
co-monomer for the step growth polymer and any optional benefit
agent.
[0156] The benefit agent may be present in the reaction mixture, at
a level to give the benefit agent levels in the resulting particles
at the levels disclosed above, although it is also possible to form
"empty" particles and subsequently expose them to a benefit agent
which can be adsorbed into the inner region.
[0157] Surface modification materials are generally added to the
aqueous phase towards the end of the process, where, for example,
further monomer(s) can be added to form further shell material and
bind additional materials to the outside of the particle.
Emulsifying Agents
[0158] Many emulsifying agents are known for use in emulsion
polymerisation. Suitable emulsifying agents for use in the
polymerisation process may comprise, but are not limited to,
non-ionic surfactants such as polyvinylpyrrolidone (PVP),
polyethylene glycol sorbitan monolaurate (Tween 20), polyethylene
glycol sorbitan monopalmitate (tween 40), polyethylene glycol
sorbitan monooleate (Tween 80), polyvinyl alcohol (PVA), and
poly(ethoxy)nonyl phenol, ethylene maleic anhydride (EMA)
copolymer, Easy-Sperse.TM. (from ISP Technologies Inc.), ionic
surfactants such as partially neutralized salts of polyacrylic
acids such as sodium or potassium polyacrylate or sodium or
potassium polymethacrylate. Brij.TM.-35, Hypermer.TM. A 60, or
sodium lignosulphate, and mixtures thereof.
[0159] Emulsifiers may also include, but are not limited to,
acrylic acid-alkyl acrylate copolymer, poly(acrylic acid),
polyoxyalkylene sorbitan fatty esters, polyalkylene co-carboxy
anhydrides, polyalkylene co-maleic anhydrides, poly(methyl vinyl
ether-co-maleic anhydride), poly(propylene-co-maleic anhydride),
poly(butadiene co-maleic anhydride), and poly(vinyl
acetate-co-maleic anhydride), polyvinyl alcohols, polyalkylene
glycols, polyoxyalkylene glycols, and mixtures thereof.
[0160] Preferred emulsifying agents are fatty alcohol exthoylates
(particularly of the Brij.TM. class), salts of ether sulphates
(including SLES), alkyl and alkaryl sulphonates and sulphates
(including LAS and SDS) and cationic quaternary salts (including
CTAC and CTAB).
[0161] It is particularly preferred that the emulsifying agent
comprises a nonionic surfactant. This is believed to produce a
particle which deposits better on cloth than one produced soley
with an anionic surfactant emulsifier, as cloth become anionic
during a wash. It is also preferred that the non-ionic surfactant
is hydrophilic, so as to promote the formation of a stable
mini-emulsion. The alcohol ethoxylates with more than ten moles of
ethoxylation, for example Synperonic A20 (C1320EO), yield good
results. DLS data for samples shows that as the level of surfactant
increases the particle size becomes smaller, which is also
advantageous. Preferably, the ratio of non-ionic to anionic
emulsifier should be greater than 1:1 (i.e. non-ionic is present in
excess) and the total surfactant level should be >3% wt of the
polymerisation mixture.
Co-Surfactant:
[0162] Typically a co-surfactant will be present in the dispersed
phase and in the resulting particle. Suitable co-surfactants for
use in the present invention include hexadecane, cetyl alcohol,
lauroyl peroxide, n-dodecyl mercaptan, dodecyl methacrylate,
stearyl methacrylate, polystyrene, polydecene, mineral oils,
isopropyl myristate C.sub.13-C.sub.15 alkyl benzoate and polymethyl
methacrylate.
[0163] The preferred cosurfactants comprise hexadecane, polydecene
and isopropyl myristate.
[0164] As a wt % of oil phase as a total, the co-surfactant is
typically 0-20%, preferably 1-15%, more pref 2-12.5%.
Catalyst
[0165] Optional catalyst may be present in the dispersed phase of
the emulsion. This advantageously minimises the hydrolysis of
isocyanate to primary amine, which can react with further
isocyanate to form polyurea. This unwanted reaction can result in
an excess of diol being left at the end of the process which can
potentially lead to the formation of malodour and interfere with
cross-linking reactions.
[0166] Suitable catalysts may comprise amino or organo-metalic
compounds such as N,N'-dimethylaminoethanol,
N,N'-dimethylcyclohexylamine, bis-(2-dimethylaminoethyl)ether,
N,N'-dimethylacetylamine, diaminobicyclooctane, stannous octoate
and dibutyl tin dilaurate, 1,3-bis(dimethylamino) butane,
pentamethyldiethylenetriamine and mixtures thereof.
[0167] The level of catalyst is typically 0.1-2% with respect to
chain-growth monomer.
Polymerisation Conditions
[0168] As noted above, polymerisation typically occurs in at least
two phases. In the earlier phase the shell is preferably formed by
a reaction which, in preferred embodiments occurs at less than
about 60 Celsius, typically 15-55 Celsius. In the later phase the
inner region is polymerised at a preferred temperature of more than
about 70 Celcius, typically 70-95 Celcius.
[0169] Both reactions are allowed to proceed for sufficiently long
for polymerisation to be essentially complete, 1-3 hours being
typical for each stage.
[0170] Deposition aid may added at the end of the later phase
(preferably after cooling), when for example, further shell forming
material (for example further isocyanate and co-momomer) are also
added to bind the deposition aid to the outer surface of the
particle by the formation of further shell material which entraps a
portion of the deposition aid and leads to a "hairy" particle in
which the "hair" comprises the deposition aid.
[0171] For simple core-shell particles, the core excluding benefit
agent is less than or equal to 80% wt of mass, and the shell
generally 20% wt or greater of the mass of the particle.
[0172] Preferably the emulsion polymerisation step is a so-called
"mini-emulsion" polymerisation, performed with a dispersed phase
droplet size of below one micron. Sufficiently fine emulsions can
be obtained by a range of methods, including sonication, and/or via
high shear dynamic mixers or static mixers. Mini-emulsion products
have excellent suspending properties.
Formaldehyde Scavenger:
[0173] Compositions including the particles of present invention
can comprise (if required) a formaldehyde scavenger. The
formaldehyde scavengers disclosed in EP 1797947 can be used in
embodiments of the invention. In the alternative a formaldehyde
scavenger can be added at the end of polymerisation to the aqueous
phase of the reaction mixture.
[0174] The formaldehyde scavengers of the present invention are
preferably selected from beta-dicarbonyl compounds, mono- or
di-amide materials, amines and other materials which can react with
formaldehyde and remove it.
[0175] Suitable beta-dicarbonyl compounds of the present have an
acidic hydrogen giving rise to a nucleophilic attack on
formaldehyde.
[0176] Preferred beta-dicarbonyl compounds are acetoacetamide (BKB
(available in the marketplace from Eastman)), ethyl acetoacetate
(EAA (available in the marketplace from Eastman)),
N,N-Dimethyleneacetamide (DMAA (available in the marketplace from
Eastman)), acetoacetone, dimethyl-1,3-acetonedicarboxylate,
1,3-acetonedicarboxylic acid, malonic acid, resorcinol,
1,3-cyclohexadione, barbituric acid,
5,5-dimethyl-1,3-cyclohexanedione (dimedone),
2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid), salicylic
acid, methyl acetoacetate (MAA (available in the marketplace from
Eastman)), ethyl-2-methyl acetoacetate, 3-methyl-acetoacetone,
dimethyl malonate, diethyl malonate, 1,3-dimethyl barbituric acid,
resorcinol, phloroglucinol, orcinol, 2,4-dihydroxy benzoic acid,
3,5dihydroxy benzoic acid, and malonamide. Other suitable
beta-dicarbonyl scavenger are listed in U.S. Pat. Nos. 5,194,674
and 5,446,195 as well as in Tomasino et al, Textile Chemist and
Colorist, vol. 16, No. 12 (1984),
[0177] Mono or Di-amides may also be used as effective formaldehyde
scavengers.
[0178] Examples of the preferred effective mono- and di-amide
scavengers are urea, ethylene urea, propylene urea, caprolactam,
glycouril, hydantoin, 2-oxazolidinone, 2-pyrrolidinone, uracil,
barbituric acid, thymine, uric acid, allantoin, polyamides,
4,5-dihydroxyethylene urea,
monomethylol-4-hydroxy-4-methoxy-5,5-dimethyl-propylurea, nylon
2-hydroxyethyl ethylene urea (SR-511; SR-512 (Sartomer)),
2-hydroxyethyl urea (Hydrovance (National Starch)), L-citrulline,
biotin, N-methyl urea, N-ethyl urea, N-butyl urea, N-phenyl urea,
4,5-dimethoxy ethylene urea and succinimide.
[0179] Another class of compounds that are effective formaldehyde
scavengers are amines which form imines by reaction with
formaldehyde.
[0180] Preferred amines include, poly(vinyl amine) (Lupamin.TM.
(BASF)), arginine, lysine, asparagines, proline, tryptophan,
2-amino-2-methyl-1-propanol (AMP); proteins such as casein,
gelatin, collagen, whey protein, soy protein, and albumin;
melamine, benzoguanamine, 4-aminobenzoic acid (PABA),
3-aminobenzoic acid, 2-aminobenzoic acid (anthranilic acid),
2-aminophenol, 3-aminophenol, 4-aminophenol, creatine,
4-aminosalicylic acid, 5-aminosalicylic acid, methyl anthranilate,
methoxy]amine HCl, anthranilamide, 4-aminobenzamide, p-toluidine,
p-anisidine, sulfanilic acid, sulfanilamide,
methyl-4-aminobenzoate, ethyl-4-aminobenzoate (benzocain),
beta-diethylaminoethyl-4-aminobenzoate (procain), 4-aminobenzamide,
3,5-diaminobenzoic acid and 2,4-diaminophenol.
[0181] Other amines as disclosed in copending U.S. Letters for
patent application Ser. No. 11/123,898 and U.S. Pat. No. 6,261,483,
and in Tomasino et al, Textile Chemist and Colorist, vol. 16, No.
12 (1984).
[0182] Other formaldehyde scavengers are known, for example,
hydrazines such as 2,4-dinitrophenzylhydrazine react with
formaldehyde to give hydrazones. The reaction is pH-dependent and
reversible. Other preferred amines can be selected from a
non-limiting list of 1,2-phenylenediamine, 1,3-phenylenediamine,
and 1,4-phenylenediamine.
[0183] In addition, aromatic amines, triamines, and aliphatic
polyamine may also be used. Examples of these amines may include,
but are not limited to, aniline, hexamethylene-diamine,
bis-hexamethylenetriamine, triethyl-aminetriamine,
poly(propyleneoxide) triamine, and
poly(propyleneglycol)-diamines.
[0184] The formaldehyde scavengers of WO 2007/091223 may also be
used in embodiments of the invention. These are sodium bisulfite,
urea, cysteine, cysteamine, lysine, glycine, serine, carnosine,
histidine, glutathione, 3,4-diaminobenzoic acid, allantoin,
glycouril, anthranilic acid, methyl anthranilate, methyl
4aminobenzoate, ethyl acetoacetate, acetoacetamide, malonamide,
ascorbic acid, 1,3dihydroxyacetone dimer, biuret, oxamide,
benzo-guanamine, pyroglutamic acid, pyrogallol, methyl gallate,
ethyl gallate, propyl gallate, triethanol amine, succinamide,
thiabendazole, benzotriazol, triazole, indoline, sulfanilic acid,
oxamide, sorbitol, glucose, cellulose, poly(vinyl alcohol),
poly(vinyl amine), hexane diol,
ethylenediamine-N,N'-bisacetoacetamide,
N-(2-ethylhexyl)acetoacetamide, N-(3-phenylpropyl) acetoacetamide,
lilial, helional, melonal, triplal,
5,5-dimethyl-1,3-cyclohexanedione,
2,4-dimethyl-3-cyclohexenecarboxaldehyde,
2,2-dimethyl-1,3-dioxan-4,6-dione, 2-pentanone, dibutyl amine,
triethylenetetramine, benzylamine, hydroxycitronellol,
cyclohexanone, 2-butanone, pentane dione, dehydroacetic acid,
chitosan, and/or mixtures thereof.
[0185] Particularly preferred scavengers comprise at least one of
urea, ethylene urea, ethylacetamide, acetoacetamide and mixtures
thereof. The most preferred scavengers are selected from the group
consisting of urea, ethylene urea, ethyl-acetamide, acetoacetamide
and mixtures thereof.
Particularly Preferred Embodiments:
[0186] The invention most preferably subsists in a particle having
an average diameter of less than 50 micron comprising: [0187] a) at
least one polyurethane shell; [0188] b) interior to said shell, a
solid core formed by chain growth polymerisation of ethylenically
unsaturated species, preferably comprising acrylates and/or
methacrylates.
[0189] It is particularly preferred that the above particle
comprises a fragrance absorbed in the core, and/or a
poly-saccharide deposition aid exterior to the shell. Especially
preferred particles have a particle size of 50-500 nm. As will be
described in further detail below, the particles find particularly
advantageous application in compositions which are intended for the
treatment of the surface of skin, hair or laundry where the
deposition aid is selected such that it is substantive to the
surface being treated.
Use in Products
[0190] The end-product compositions of the invention may be in any
physical form e.g. a solid such as a powder or granules, a tablet,
a solid bar, a paste, gel or liquid, especially, an aqueous-based
liquid.
[0191] The particles of the invention may be advantageously
incorporated into surfactant-containing and, in particular laundry
and personal care compositions. The particles are typically
included in said compositions at levels of from 0.001% to 10%,
preferably from 0.005% to 7.55%, most preferably from 0.01% to 5%
by weight of the total composition.
[0192] For laundry applications, one active ingredient in the
compositions is preferably a surface active agent or a fabric
conditioning agent. More than one active ingredient may be
included. For some applications a mixture of active ingredients may
be used.
[0193] Formulated compositions comprising the particles of the
invention may contain a surface-active compound (surfactant) which
may be chosen from soap and non soap anionic, cationic, non-ionic,
amphoteric and zwitterionic surface active compounds and mixtures
thereof. Many suitable surface active compounds are available and
are fully described in the literature, for example, in
"Surface-Active Agents and Detergents", Volumes I and II, by
Schwartz, Perry and Berch. The preferred surface-active compounds
that can be used are soaps and synthetic non soap anionic, and
non-ionic compounds.
[0194] The compositions of the invention may contain linear
alkylbenzene sulphonate, particularly linear alkylbenzene
sulphonates having an alkyl chain length of from 08 to 015. It is
preferred if the level of linear alkylbenzene sulphonate is from 0
wt % to 30 wt %, more preferably from 1 wt % to 25 wt %, most
preferably from 2 wt % to 15 wt %, by weight of the total
composition.
[0195] Compositions may contain other anionic surfactants in
amounts additional to the percentages quoted above. Suitable
anionic surfactants are well-known to those skilled in the art.
Examples include primary and secondary alkyl sulphates,
particularly C8 to C15 primary alkyl sulphates; alkyl ether
sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl
sulphosuccinates; and fatty acid ester sulphonates. Sodium salts
are generally preferred.
[0196] Compositions may also contain non-ionic surfactant. Nonionic
surfactants that may be used include the primary and secondary
alcohol ethoxylates, especially the 08 to 020 aliphatic alcohols
ethoxylated with an average of from 1 to 20 moles of ethylene oxide
per mole of alcohol, and more especially the 010 to 015 primary and
secondary aliphatic alcohols ethoxylated with an average of from 1
to 10 moles of ethylene oxide per mole of alcohol. Non ethoxylated
nonionic surfactants include alkylpolyglycosides, glycerol
monoethers, and polyhydroxyamides (glucamide).
[0197] It is preferred if the level of non-ionic surfactant is from
0 wt % to 30 wt %, preferably from 1 wt % to 25 wt %, most
preferably from 2 wt % to 15 wt %, by weight of a fully formulated
composition comprising the particles of the invention.
[0198] Any conventional fabric conditioning agent may be used. The
conditioning agents may be cationic or non-ionic. If the fabric
conditioning compound is to be employed in a main wash detergent
composition the compound will typically be non-ionic. For use in
the rinse phase, typically they will be cationic. They may for
example be used in amounts from 0.5% to 35%, preferably from 1% to
30% more preferably from 3% to 25% by weight of a fully formulated
composition comprising the particles of the invention.
[0199] Suitable cationic fabric softening compounds are
substantially water-insoluble quaternary ammonium materials
comprising a single alkyl or alkenyl long chain having an average
chain length greater than or equal to C20 or, more preferably,
compounds comprising a polar head group and two alkyl or alkenyl
chains having an average chain length greater than or equal to C14.
Preferably the fabric softening compounds have two long chain alkyl
or alkenyl chains each having an average chain length greater than
or equal to C16. Most preferably at least 50% of the long chain
alkyl or alkenyl groups have a chain length of C18 or above. It is
preferred if the long chain alkyl or alkenyl groups of the fabric
softening compound are predominantly linear.
[0200] Quaternary ammonium compounds having two long-chain
aliphatic groups, for example, distearyldimethyl ammonium chloride
and di(hardened tallow alkyl) dimethyl ammonium chloride, are
widely used in commercially available rinse conditioner
compositions. Other examples of these cationic compounds are to be
found in "Surfactants Science Series" volume 34 ed. Richmond 1990,
volume 37 ed. Rubingh 1991 and volume 53 eds. Cross and Singer
1994, Marcel Dekker Inc. New York".
[0201] The fabric softening compounds are preferably compounds that
provide excellent softening, and are characterised by a chain
melting L.beta. to La transition temperature greater than 25
Celsius, preferably greater than 35 Celsius, most preferably
greater than 45 Celsius. This L.beta. to La transition can be
measured by differential scanning calorimetry as defined in
"Handbook of Lipid Bilayers", D Marsh, CRC Press, Boca Raton, Fla.,
1990 (pages 137 and 337).
[0202] Substantially water-insoluble fabric softening compounds are
defined as fabric softening compounds having a solubility of less
than 1.times.10-3 wt % in demineralised water at 20 Celsius.
Preferably the fabric softening compounds have a solubility of less
than 1.times.10-4 wt %, more preferably from less than 1.times.10-8
to 1.times.10-6 wt %.
[0203] Especially preferred are cationic fabric softening compounds
that are water-insoluble quaternary ammonium materials having two
C12-22 alkyl or alkenyl groups connected to the molecule via at
least one ester link, preferably two ester links.
Di(tallowoxyloxyethyl) dimethyl ammonium chloride and/or its
hardened tallow analogue is an especially preferred compound of
this class.
[0204] A second preferred type comprises those derived from
triethanolamine (hereinafter referred to as `TEA quats`) as
described in for example U.S. Pat. No. 3,915,867. Suitable
materials are, for example, N-methyl-N,N,N-triethanolamine
ditallowester or di-hardened-tallowester quaternary ammonium
chloride or methosulphate. Examples of commercially available TEA
quats include Rewoquat WE18 and Rewoquat WE20, both partially
unsaturated (ex. WITCO), Tetranyl AOT-1, fully saturated (ex. KAO)
and Stepantex VP 85, fully saturated (ex. Stepan).
[0205] It is advantageous if the quaternary ammonium material is
biologically biodegradable.
[0206] It is also possible to include certain mono-alkyl cationic
surfactants which can be used in main-wash compositions for
fabrics. Cationic surfactants that may be used include quaternary
ammonium salts of the general formula R1R2R3R4N+X-- wherein the R
groups are long or short hydrocarbon chains, typically alkyl,
hydroxyalkyl or ethoxylated alkyl groups, and X is a counter-ion
(for example, compounds in which R1 is a C8-C22 alkyl group,
preferably a C8-C10 or C12-C14 alkyl group, R2 is a methyl group,
and R3 and R4, which may be the same or different, are methyl or
hydroxyethyl groups); and cationic esters (for example, choline
esters).
[0207] The choice of surface-active compound (surfactant), and the
amount present, will depend on the intended use of the detergent
composition. In fabric washing compositions, different surfactant
systems may be chosen, as is well known to the skilled formulator,
for hand-washing products and for products intended for use in
different types of washing machine.
[0208] The total amount of surfactant present will also depend on
the intended end use and may, in fully formulated products, be as
high as 60 wt %, for example, in a composition for washing fabrics
by hand. In compositions for machine washing of fabrics, an amount
of from 5 to 40 wt % is generally appropriate. Typically
compositions will comprise at least 2 wt % surfactant e.g. 2-60%,
preferably 15-40% most preferably 25-35%, by weight.
[0209] Detergent compositions suitable for use in most automatic
fabric washing machines generally contain anionic non-soap
surfactant, or non-ionic surfactant, or combinations of the two in
any suitable ratio, optionally together with soap. Compositions,
when used as main wash fabric washing compositions, will generally
also contain one or more detergency builders. The total amount of
detergency builder in compositions will typically range from 5 to
80 wt %, preferably from 10 to 60 wt %, by weight of
composition.
[0210] Inorganic builders that may be present include sodium
carbonate, if desired in combination with a crystallisation seed
for calcium carbonate, as disclosed in GB 1 437 950 (Unilever);
crystalline and amorphous aluminosilicates, for example, zeolites
as disclosed in GB 1 473 201 (Henkel), amorphous aluminosilicates
as disclosed in GB 1 473 202 (Henkel) and mixed
crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250
(Procter & Gamble); and layered silicates as disclosed in EP
164 514B (Hoechst). Inorganic phosphate builders, for example,
sodium orthophosphate, pyrophosphate and tripolyphosphate are also
suitable for use with this invention.
[0211] The compositions of the invention preferably contain an
alkali metal, preferably sodium, aluminosilicate builder. Sodium
aluminosilicates may generally be incorporated in end product
formulations amounts of from 10 to 70% by weight (anhydrous basis),
preferably from 25 to 50 wt %.
[0212] The alkali metal aluminosilicate may be either crystalline
or amorphous or mixtures thereof, having the general formula: 0.8
1.5 Na2O. Al2O3. 0.8 6 SiO2
[0213] These materials contain some bound water and are required to
have a calcium ion exchange capacity of at least 50 mg CaO/g. The
preferred sodium aluminosilicates contain 1.5 3.5 SiO2 units (in
the formula above). Both the amorphous and the crystalline
materials can be prepared readily by reaction between sodium
silicate and sodium aluminate, as amply described in the
literature. Suitable crystalline sodium aluminosilicate ion
exchange detergency builders are described, for example, in GB 1
429 143 (Procter & Gamble). The preferred sodium
aluminosilicates of this type are the well known commercially
available zeolites A and X, and mixtures thereof.
[0214] The zeolite may be the commercially available zeolite 4A now
widely used in laundry detergent powders. However, according to a
preferred embodiment of the invention, the zeolite builder
incorporated in the compositions of the invention is maximum
aluminium zeolite P (zeolite MAP) as described and claimed in EP
384 070A (Unilever). Zeolite MAP is defined as an alkali metal
aluminosilicate of the zeolite P type having a silicon to aluminium
weight ratio not exceeding 1.33, preferably within the range of
from 0.90 to 1.33, and more preferably within the range of from
0.90 to 1.20.
[0215] Especially preferred is zeolite MAP having a silicon to
aluminium weight ratio not exceeding 1.07, more preferably about
1.00. The calcium binding capacity of zeolite MAP is generally at
least 150 mg CaO per g of anhydrous material.
[0216] Organic builders that may be present include polycarboxylate
polymers such as polyacrylates, acrylic/maleic copolymers, and
acrylic phosphinates; monomeric polycarboxylates such as citrates,
gluconates, oxydisuccinates, glycerol mono, di and trisuccinates,
carboxymethyloxy succinates, carboxymethyloxymalonates,
dipicolinates, hydroxyethyliminodiacetates, alkyl and
alkenylmalonates and succinates; and sulphonated fatty acid salts.
This list is not intended to be exhaustive.
[0217] Especially preferred organic builders are citrates, suitably
used in fully formulated compositions in amounts of from 5 to 30 wt
%, preferably from 10 to 25 wt %; and acrylic polymers, more
especially acrylic/maleic copolymers, suitably used in amounts of
from 0.5 to 15 wt %, preferably from 1 to 10 wt %.
[0218] Builders, both inorganic and organic, are preferably present
in alkali metal salt, especially sodium salt, form.
[0219] Compositions comprising particles according to the invention
may also suitably contain a bleach system. Fabric washing
compositions may desirably contain peroxy bleach compounds, for
example, inorganic persalts or organic peroxyacids, capable of
yielding hydrogen peroxide in aqueous solution.
[0220] Suitable peroxy bleach compounds include organic peroxides
such as urea peroxide, and inorganic persalts such as the alkali
metal perborates, percarbonates, perphosphates, persilicates and
persulphates. Preferred inorganic persalts are sodium perborate
monohydrate and tetrahydrate, and sodium percarbonate.
[0221] Especially preferred is sodium percarbonate having a
protective coating against destabilisation by moisture. Sodium
percarbonate having a protective coating comprising sodium
metaborate and sodium silicate is disclosed in GB 2 123 044B
(Kao).
[0222] The peroxy bleach compound is suitably present in a fully
formulated product in an amount of from 0.1 to 35 wt %, preferably
from 0.5 to 25 wt %. The peroxy bleach compound may be used in
conjunction with a bleach activator (bleach precursor) to improve
bleaching action at low wash temperatures. The bleach precursor is
suitably present in an amount of from 0.1 to 8 wt %, preferably
from 0.5 to 5 wt %.
[0223] Preferred bleach precursors are peroxycarboxylic acid
precursors, more especially peracetic acid precursors and
pernoanoic acid precursors. Especially preferred bleach precursors
suitable for use in the present invention are N,N,N',N', tetracetyl
ethylenediamine (TAED) and sodium nonanoyloxybenzene sulphonate
(SNOBS). The novel quaternary ammonium and phosphonium bleach
precursors disclosed in U.S. Pat. No. 4,751,015 and U.S. Pat. No.
4,818,426 (Lever Brothers Company) and EP 402 971A (Unilever), and
the cationic bleach precursors disclosed in EP 284 292A and EP 303
520A (Kao) are also of interest.
[0224] The bleach system can be either supplemented with or
replaced by a peroxyacid. Examples of such peracids can be found in
U.S. Pat. No. 4,686,063 and U.S. Pat. No. 5,397,501 (Unilever). A
preferred example is the imido peroxycarboxylic class of peracids
described in EP A 325 288, EP A 349 940, DE 382 3172 and EP 325
289. A particularly preferred example is phthalimido peroxy caproic
acid (PAP). Such peracids are suitably present at 0.1-12% wt,
preferably 0.5-10% wt.
[0225] A bleach stabiliser (transition metal sequestrant) may also
be present in fully formulated products. Suitable bleach
stabilisers include ethylenediamine tetra-acetate (EDTA), the
polyphosphonates such as Dequest (Trade Mark) and non phosphate
stabilisers such as EDDS (ethylene diamine di succinic acid). These
bleach stabilisers are also useful for stain removal especially in
end-products containing low levels of bleaching species or no
bleaching species.
[0226] An especially preferred bleach system comprises a peroxy
bleach compound (preferably sodium percarbonate optionally together
with a bleach activator), and a transition metal bleach catalyst as
described and claimed in EP 458 397A, EP 458 398A and EP 509 787A
(Unilever).
[0227] Advantageously in the compositions of the invention benefit
agents, particularly, perfume components may be employed which are
sensitive to bleaches as the encapsulation of, for example, the
perfume component within the particles will provide some degree of
protection to the perfume component or other benefit agent.
[0228] The fully formulated compositions may also contain one or
more enzyme(s).
[0229] Suitable enzymes include the proteases, amylases,
cellulases, oxidases, peroxidases and lipases usable for
incorporation in detergent compositions. Preferred proteolytic
enzymes (proteases) are, catalytically active protein materials
which degrade or alter protein types of stains when present as in
fabric stains in a hydrolysis reaction. They may be of any suitable
origin, such as vegetable, animal, bacterial or yeast origin.
[0230] Proteolytic enzymes or proteases of various qualities and
origins and having activity in various pH ranges of from 4-12 are
available and can be used in the instant invention. Examples of
suitable proteolytic enzymes are the subtilisins which are obtained
from particular strains of B. Subtilis B. lichenifonnis, such as
the commercially available subtilisins Maxatase (Trade Mark), as
supplied by Genencor International N.V., Delft, Holland, and
Alcalase (Trade Mark), as supplied by Novozymes Industri NS,
Copenhagen, Denmark.
[0231] Particularly suitable is a protease obtained from a strain
of Bacillus having maximum activity throughout the pH range of
8-12, being commercially available, e.g. from Novozymes Industri
A/S under the registered trade names Esperase (Trade Mark) and
Savinase (Trade Mark). The preparation of these and analogous
enzymes is described in GB 1 243 785. Other commercial proteases
are Kazusase (Trade Mark obtainable from Showa Denko of Japan),
Optimase (Trade Mark from Miles Kali Chemie, Hannover, West
Germany), and Superase (Trade Mark obtainable from Pfizer of
U.S.A.).
[0232] Detergency enzymes are commonly employed in fully formulated
products in granular form in amounts of from about 0.1 to about 3.0
wt % on product. However, any suitable physical form of enzyme may
be used. Advantageously in the compositions of the invention
benefit agents, for example, perfume components, may be employed
which are sensitive to enzymes as the encapsulation of the perfume
component (or other benefit agent) within the particles will
provide some degree of protection to the perfume component (or
other benefit agent).
[0233] The compositions of the invention may contain alkali metal,
preferably sodium carbonate, in order to increase detergency and
ease processing. Sodium carbonate may suitably be present in fully
formulated products in amounts ranging from 1 to 60 wt %,
preferably from 2 to 40 wt %. However, compositions containing
little or no sodium carbonate are also within the scope of the
invention.
[0234] The fully formulated detergent composition when diluted in
the wash liquor (during a typical wash cycle) will typically give a
pH of the wash liquor from 7 to 10.5 for a main wash detergent.
[0235] Particulate detergent compositions are suitably prepared by
spray drying a slurry of compatible heat insensitive ingredients,
and then spraying on or post-dosing those ingredients unsuitable
for processing via the slurry. The skilled detergent formulator
will have no difficulty in deciding which ingredients should be
included in the slurry and which should not. It is particularly
useful to add the perfume particles of the present invention via
post-dosing.
[0236] Particulate detergent compositions preferably have a bulk
density of at least 400 g/litre, more preferably at least 500
g/litre. Especially preferred compositions have bulk densities of
at least 650 g/litre, more preferably at least 700 g/litre.
[0237] Such powders may be prepared either by post tower
densification of spray dried powder, or by wholly non tower methods
such as dry mixing and granulation; in both cases a high-speed
mixer/granulator may advantageously be used. Processes using high
speed mixer/granulators are disclosed, for example, in EP 340 013A,
EP 367 339A, EP 390 251A and EP 420 317A (Unilever).
[0238] Liquid detergent compositions can be prepared by admixing
the essential and optional ingredients thereof in any desired order
to provide compositions containing components in the requisite
concentrations. Liquid compositions according to the present
invention can also be in compact form which means it will contain a
lower level of water compared to a conventional liquid
detergent.
[0239] As noted above the particles of the present invention are
particularly suited to processes for manufacture of products which
feature "late variant addition" of benefit agents (particularly of
perfume).
[0240] In order that the present invention may be still further
understood and carried forth into practice it will be further
described with reference to the following examples:
EXAMPLES
General
Benefit Agent
[0241] Perfumes tend to be complex mixtures of molecules. For the
purpose of these examples, a simplified and reproducible model
perfume was used unless otherwise stated. The model perfume is
split into three compositions relating to top, middle and base
notes.
Top Note Perfume Composition:
TABLE-US-00001 [0242] Component Cas No. Wt % ClogP MW Mass/g melon
valerate 39255-32-8 20 2.411 153 144.21 Aldehyde C8 124-13-0 20
2.765 128.21 Tetra hydro Linalol 78-69-3 20 3.241 220 158.28 benzyl
acetate 140-11-4 20 1.604 214 150.17 Linalyl Acetate 115-95-7 20
3.114 220 196.29
Middle Note Perfume Composition:
TABLE-US-00002 [0243] Component Cas No. Wt % ClogP MW Mass/g OTBCA
88-41-5 35 3.112 198.30 damascone, delta 57378-68-4 5 3.387 267
192.30 aldehyde c12 112-54-9 20 4.59 223 184.32 verdyl acetate
5413-60-5 20 1.766 175 192.25 ionone beta 14901-07-6 20 3.355
192.30
Base Note Perfume Composition:
TABLE-US-00003 [0244] Component Cas No. Wt % ClogP MW Mass/g
bangalol 28219-61-6 20 3.728 208.34 iso E super (OTNE) 54464-57-2
20 4.138 234.38 hexyl cinnamic 101-86-0 20 4.677 216.32 aldehyde
cyclopentadecanolide 106-02-5 20 5.294 303 240.38 phenyl ethyl 2
102-20-5 20 3.624 324 240.30 phenylacetate
Particle Preparation
[0245] A general procedure was followed for all mini-emulsion
synthesis; a typical example is as follows. [0246] 1. The following
were combined in a 30 ml vial: [0247] Poly(phenyl isocyanate) (3.86
g)--cross-linker for step-growth polymerisation; [0248] isophorone
diisocyanate (8.05 g)--co-monomer for step-growth polymerisation;
[0249] top note perfume (3.2 g)--benefit agent (when present);
[0250] dibutyl tin dilaurate (0.088 g)--catalyst; [0251] hexadecane
(1.23 g)--co-surfactant; [0252] methyl methacrylate (8.32
g)--monomer for chain-growth polymerisation; [0253]
2,2'-azobisisobutyronitrile (0.083 g)--free-radical initiator for
chain-growth polymerisation; [0254] 2. The following were dissolved
in 67.1 g water and cooled to below 10.degree. C.: [0255] Sodium
dodecyl sulphate (1.23 g)--emulsifier; [0256]
1,1,1-tris(hydroxymethyl)propane (1.52 g)--cross-linker for
step-growth [0257] polymer 1,6-hexane diol (4.28 g)--co-monomer for
step-growth polymerisation; [0258] 3. Using a sonic probe, the two
phases obtained at (1) and (2) were mixed for three minutes whilst
cooled in an ice bath. [0259] 4. The mini-emulsion solution
resulting from step (3) was placed in a round bottom flask and
stirred at an external temperature of 55.degree. C. and 200 rpm for
three hours. [0260] 5. After three hours the temperature was
increased to 85.degree. C. and the reaction stirred for a further
two hours. [0261] 6. After five hours the reaction was cooled and
decanted.
[0262] The reaction vessel and stirrer should be checked for signs
of coagulation and grit formation. Final solids content was
determined by gravimetric analysis.
Procedure for Cotton Deposition Aid Grafting:
[0263] 1. Prepare 1% LBG/Xyloglucan by dissolving 1 g
poly(saccharide) in 99 g boiling water by stirring with a
homogeniser at 12,000 rpm for 2 minutes. [0264] 2. Weigh 100 g of
20% solids (mini)emulsion particles into round bottom flask. [0265]
3. To this, add 20 g of poly(saccharide) stock solution. [0266] 4.
Attach an overhead stirrer and condenser and heat to 80.degree. C.
[0267] 5. After the mixture has been stirred at 350 rpm for 1 hour
add ascorbic acid (0.096 g in 1 ml water) and methyl acrylate (1.01
g) [0268] 6. Allow the mixture to stir for 2 minutes before adding
30% hydrogen peroxide solution (0.275 g) [0269] 7. After 90 minutes
add a further portion of ascorbic acid (0.032 in 0.5 ml water) and
30% hydrogen peroxide (0.09 g) [0270] 8. Once the reaction has
finished (3-4-h) allow the reaction to cool, and transfer to a
labelled jar.
Procedure for Polyester Deposition Aid Grafting:
[0270] [0271] 1. Prepare 1% PET-POET by dissolving 1 g polymer in
99 g boiling water by stirring with a homogeniser at 12,000 rpm for
2 minutes. [0272] 2. Weigh 100 g of 20% solids (mini)emulsion
particle into round bottom flask. [0273] 3. To this, add 20 g of
poly(saccharide) stock solution. [0274] 4. Attach an overhead
stirrer and condenser and heat to 80.degree. C. for 1 hour. [0275]
5. Cool the reaction back to 25.degree. C. [0276] 6. Add dropwise
over five minutes isophorone diisocyanate (2.17 g) and
dibutyltindilaurate (0.03 g) and stir for a further 55 minutes.
[0277] 7. Add 1,6-hexanediol (1.16 g) dissolved in water (1.65 g)
and heat to 80.degree. C. and stir for two hours [0278] 8. Once the
reaction has finished (4-5 h) allow the reaction to cool, and
transfer to a labelled jar.
Washing Experiments:
[0279] In washing experiments particle deposition was measured by
turbidity as follows:
a) Preparation of stock solutions: [0280] Surfactant Stock: (10 g/L
50:50 LAS:A7) was prepared by dissolving Linear Alkyl Benzene
Sulphonate (9.09 g LAS (55% Active)) and Synperonic A7 (5 g) in
de-ionised water to a total of 1 litre. [0281] Base Buffer Stock:
(0.1 M) was prepared by dissolving Sodium Carbonate (7.5465 g) and
Sodium Hydrogen Carbonate (2.4195 g) in de-ionised water to a total
of 1 litre.
b) Preparation of the Wash Liquor:
[0281] [0282] Base Buffer Stock (10 ml) and surfactant stock (10
ml) were added to a 500 ml Linitest pot and 80 ml de-ionised water
was added to produce a wash liquor buffered at pH 10.5 and
containing 1 g/L surfactant (50:50 LAS:A7).
c) Simulated Wash:
[0282] [0283] 0.04 g (400 ppm on wash liquor) of polymer particles:
Unmodified capsules were each added to the linitest pots containing
wash liquor and agitated slightly to ensure mixing. Washes were
done in duplicate for each sample and results averaged. A 5 ml
aliquot was taken from each and the Absorbance at 400 nm recorded
using a 1 cm cuvette. This absorbance value represents 100%
particles in the wash solution prior to the simulated simulated
wash process.
d) Linitest Equipment and Procedure:
[0284] A section of unfluoresced cotton (or knitted polyester as
appropriate) measuring 20 cm by 20 cm was placed into each linitest
pot containing the wash liquor and polymer particles and the pot
was sealed.
[0285] The Linitest.TM. is a laboratory scale washing machine (Ex.
Heraeus). The equipment is designed and built to comply with the
requirements for international standard test specifications. It is
used for small scale detergency and stain removal testing
particularly when low liquor to cloth ratios are required.
[0286] There are various models of the Linitest commercially
available. The model used in this case has a single rotation speed
of 40 rpm. The carrier is capable of accommodating twelve 500 ml
steel containers and can be operated at temperatures up to
100.degree. C.
[0287] The Linitest comprises a 20 litre tank, control system and
drive mechanism. Permanent thermostatically controlled tubular
heating elements in the base of the tank heat the bath liquor to
the required temperature. The stainless steel construction
throughout ensures efficient heat transfer to the specimen
containers that are mounted on a rotating horizontal carrier driven
by a geared motor. The rotating movement of the carrier `throws`
the liquid from one end of the container to the other in a
continuous action. This movement simulates the mechanical washing
process and additional mechanical action can be obtained by using
steel ball bearings or discs.
[0288] The Linitest pots were attached to the Linitester cradle and
rotated 45 minutes at 40.degree. C. to simulate the main wash.
[0289] The cloths were then removed and wrung by hand and a 5 ml
aliquot of the remaining wash liquor was taken and the absorbance
at 400 nm measured using a 1 cm cuvette as before. From
interpolation of the initial calibration curve, the concentration
of the particles remaining the liquor after the wash could be
determined and hence the level deposited (wash deposition) on the
cloth could be determined by difference.
[0290] The Linitest pots were then thoroughly rinsed and the
`wrung` cloths returned to the pots and 125 ml of de-ionised water
was added. The Linitester bath water was drained and the pots
attached to the cradle and rotated for 10 minutes at ambient
temperature (.about.20.degree. C.) to simulate a rinse procedure.
The clothes were then removed and wrung by hand. A 5 ml aliquot of
the rinse solution was taken and the absorbance at 400 nm
determined. As before interpolation of the initial calibration plot
allowed the particle concentration removed from the cloth during
the rinse to be determined and by comparison to the initial level
deposited prior to the rinse, the percentage loss from the cloth
could be determined. This procedure was repeated a further two
times to simulate and determine losses from the second and third
rinse.
[0291] In the following examples, all quantities are given in grams
unless otherwise specified. Perfume retention within the particles
is determined by placing the particles in a model laundry detergent
formulation and determining the proportion of the perfume that
remains free after an elapsed time. Decrease in perfume content in
the surfactant base was determined by a colorimetric assay.
Example 1
Poly(urethane) Miniemulsion Synthesis with Various Cross-Linker
Levels (Prior Art)
TABLE-US-00004 [0292] Experiment 1 2 3 4 5 6 7 X-Linker Level 1 2 4
8 16 32 0 Poly(phenyl 0.133 0.266 0.534 1.071 2.155 4.360 0
isocyanate) Isophorone 12.936 12.815 12.571 12.082 11.095 9.087
13.057 diisocyanate Dibutyltindilaurate 0.088 0.088 0.088 0.088
0.088 0.088 0.088 Hexadecane 0.82 0.82 0.82 0.82 0.82 0.82 0.82
Sodium dodecyl 0.82 0.82 0.82 0.82 0.82 0.82 0.82 sulphate
1,1,1-tris(hydroxyl- 0.053 0.105 0.211 0.423 0.850 1.721 0 methyl)
propane 1,6-Hexane diol 6.878 6.813 6.684 6.424 5.899 4.831 6.942
Water 78.3 78.3 78.3 78.3 78.3 78.3 78.3
[0293] The level of cross-linker refers to the percentage of
isocyanate, or hydroxyl groups, on a tri-functional molecule, i.e.
poly(phenyl isocyanate) or 1,1,1-tris(hydroxyl-methyl)propane. The
remainder is present on a difunctional, chain extending molecule,
i.e. isophorone diisocyanate or 1,6-hexane diol.
[0294] The materials prepared were added into a non-concentrated
laundry liquid base which contained 0.75% top-note perfume at 2%
solids. The materials were then analysed after 1, 5 and 8 days to
determine how much perfume had been absorbed into the particle. A
blank measurement was taken to ensure no response from the particle
itself and a T=0 measurement was prepared by adding water to the
base instead of mini-emulsion particles.
[0295] The non cross-linked particle (example 1.7) adsorbed very
little perfume. A general increase in perfume absorption was
observed with increasing cross-linker level. At the highest
cross-linker levels around 35% of the perfume has been
adsorbed.
TABLE-US-00005 Experiment 1 2 3 4 5 6 7 X-Linker Level 1 2 4 8 16
32 0 Free perfume at T = 0 100% 100% 100% 100% 100% 100% 100% Free
perfume at T = 1 77.8 73.6 73.9 72.4 64.3 66.6 98.2 day Free
perfume at T = 5 75.9 72.2 71.9 79.3 59.2 59.8 95.19 days Free
perfume at T = 8 79.9 75.1 78.8 73.5 67.4 66.1 97.6 days
Example 2
Poly(Urethane) Hybrid Mini-Emulsion Synthesis with Various
Cross-Linker Levels and Various Monomers
TABLE-US-00006 [0296] Experiment 8 9 10 11 12 13 poly(phenyl 0.264
0.264 0.264 0.264 0.264 0.264 isocyanate) Isophorone 12.692 12.692
12.692 12.692 12.692 12.692 Diisocyanate Butyl Acrylate 9.093 (BA)
Ethyl hexyl 9.093 methacrylate (EHMA) Butyl 9.093 Methacrylate
(BMA) Methyl 9.093 Methacrylate (MMA) Methyl Acrylate 9.093 (MA)
Styrene (STY) 9.093 AIBN 0.091 0.091 0.091 0.091 0.091 0.091
Dibutyl- 0.096 0.096 0.096 0.096 0.096 0.096 tindilaurate
Hexadecane 1.344 1.344 1.344 1.344 1.344 1.344 SDS 1.23 1.23 1.23
1.23 1.23 1.23 1,6-Hexane 6.748 6.748 6.748 6.748 6.748 6.748 Diol
1,1,1-Tris 0.104 0.104 0.104 0.104 0.104 0.104 (hydroxyl- methyl)
propane Water 68.65 68.65 68.65 68.65 68.65 68.65 Experiment 14 15
16 17 18 19 poly(phenyl 4.226 4.226 4.226 4.226 4.226 4.226
isocyanate) Isophorone 8.807 8.807 8.807 8.807 8.807 8.807
Diisocyanate Butyl Acrylate 9.093 (BA) Ethyl hexyl 9.093
methacrylate (EHMA) Butyl 9.093 Methacrylate (BMA) Methyl 9.093
Methacrylate (MMA) Methyl 9.093 Acrylate (MA) Styrene (STY) 9.093
AIBN 0.091 0.091 0.091 0.091 0.091 0.091 Dibutyl- 0.096 0.096 0.096
0.096 0.096 0.096 tindilaurate Hexadecane 1.344 1.344 1.344 1.344
1.344 1.344 SDS 1.344 1.344 1.344 1.344 1.344 1.344 1,6-Hexane
4.682 4.682 4.682 4.682 4.682 4.682 Diol 1,1,1-Tris 1.668 1.668
1.668 1.668 1.668 1.668 (hydroxyl- methyl) propane Water 68.65
68.65 68.65 68.65 68.65 68.65
[0297] A range of samples according to the invention at two
crosslinker levers (2% and 32%) were prepared using a selection of
different free radical monomers as given in the tables above.
[0298] The materials prepared were added into a non-concentrated
laundry liquid base which contained 0.75% top note perfume at 2%
solids. The materials were then analysed after 1, 5 and 8 days to
determine how much perfume had been absorbed into the particle. A
blank measurement was taken to ensure no response from the particle
itself and a T=0 measurement was prepared by adding water to the
base instead of particles.
[0299] Higher crosslink density samples absorbed typically 20 to 30
percent more fragrance. Initially this result appeared surprising
as it would be expected that a highly cross-linked particle would
be difficult for the fragrance to penetrate. However given that the
leakage mechanism from these materials is thermodynamically
controlled rather than kinetically controlled, the level of free
perfume should be the same from an encapsulated perfume as is it is
from a system starting with free perfume and dosed with an
identical empty particle.
TABLE-US-00007 Experiment 8 14 9 15 10 X-linker Level 2% 32% 2% 32%
2% Core Monomer BA BA EHMA EHMA BMA Free perfume at T = 0 100 100
100 100 100 Free perfume at T = 1 day 40.6 26.1 35.6 11.1 52.6 Free
perfume at T = 5 days 38.1 28.2 33.4 10.8 53.0 Free perfume at T =
8 days 41.3 29.4 37.7 13.4 52.4 Experiment 16 11 17 13 19 X-linker
Level 32% 2% 32% 2% 32% Core Monomer BMA MMA MMA STY STY Free
perfume at T = 0 100 100 100 100 100 Free perfume at T = 1 day 24.9
58.24 35.0 68.1 45.6 Free perfume at T = 5 days 19.18 62.1 24.3
64.6 41.8 Free perfume at T = 8 days 25.9 65.08 37.6 61.9 46.4
[0300] In example 1, the particles are purely a poly-urethane
step-growth polymer without a separate core material and are formed
by formed interfacial polymerisation. In this example 2, the core,
formed by a chain growth polymerisation is also present. Comparing
the results of example 2 with example 1, it can be seen that much
lower levels of free perfume are left unadsorbed with the particles
comprising a core.
[0301] Leakage can be compared with the solubility parameter value
for the core monomer. The lower the solubility parameter difference
value (Delta SP) the more compatible the fragrance is with the core
monomer. This will lead to a lower level of free perfume and hence
a lower colorimetric response when an assay is conducted. This will
translate to a lower absorption value. A correlation can be found
between solubility parameter and free fragrance.
[0302] The lowest solubility parameter value materials show the
lowest level of free perfume and conversely the highest solubility
parameter materials the highest level of free perfume.
[0303] Looking only at the higher level of cross-linker, it is
possible to see that the solubility parameters of the core vary
with the monomer used. The table below shows the effect of varying
the nature of the core monomer on the solubility parameter.
TABLE-US-00008 Monomer Delta_SP % Free Perfume EHA 1.19 11.8 BMA
1.78 23.3 BA 2.23 27.9 MMA 3.89 32.3 STY 7.28 44.6
[0304] The level of the perfume in the particles can be assumed to
be 100% minus the level of free perfume. Thus it can be seen that
the acrylate core monomers performed better than the styrene.
Example 3
Poly(Urethane) Hybrid Miniemulsion Synthesis with Various Monomers
and Various Ratios of Poly(Urethane) to Free Radical Polymer
TABLE-US-00009 [0305] Experiment 20 21 22 23 24 25 poly(phenyl
5.886 5.233 4.579 3.925 3.270 2.616 isocyanate) Isophorone 12.268
10.904 9.542 8.179 6.816 5.452 Diisocyanate Butyl 3 6 9 12 15 18
Methacrylate (BMA) AIBN 0.083 0.083 0.083 0.083 0.083 0.083
Dibutyl- 0.088 0.088 0.088 0.088 0.088 0.088 tindilaurate
Hexadecane 1.23 1.23 1.23 1.23 1.23 1.23 SDS 1.23 1.23 1.23 1.23
1.23 1.23 1,6-Hexane 6.522 5.798 5.073 4.348 3.623 2.899 Diol
1,1,1-Tris 2.323 2.065 1.807 1.549 1.290 1.032 (hydroxy- methyl)
propane Water 67.12 67.12 67.12 67.12 67.12 67.12 Experiment 26 27
28 29 30 31 poly(phenyl 5.233 3.925 2.616 5.233 3.925 2.616
isocyanate) Isophorone 10.905 8.179 5.452 10.905 8.179 5.452
Diisocyanate Ethylhexyl 6 12 18 Methacrylate (EHMA) Methyl 6 12 18
Methacrylate (MMA) AIBN 0.083 0.083 0.083 0.083 0.083 0.083
Dibutyl- 0.088 0.088 0.088 0.088 0.088 0.088 tindilaurate
Hexadecane 1.23 1.23 1.23 1.23 1.23 1.23 SDS 1.23 1.23 1.23 1.23
1.23 1.23 1,6-Hexane 5.798 4.348 2.899 5.798 4.348 2.899 Diol
1,1,1-Tris 2.065 1.549 1.032 2.065 1.549 1.032 (hydroxy- methyl)
propane Water 67.12 67.12 67.12 67.12 67.12 67.12
[0306] Example 3 shows how it is possible to vary the ratio of the
chain growth (free radical) core and the step-growth
(poly(urethane)) shell in the hybrid particle. This will affect the
level of fragrance that can be absorbed into the core. This example
shows the effect on perfume absorption from varying the level of a
butyl methacrylate (BMA) present.
TABLE-US-00010 Experiment 20 21 22 23 24 25 Step Growth:Chain 90:10
80:20 70:30 60:40 50:50 40:60 Growth (shell:core) Core Monomer BMA
BMA BMA BMA BMA BMA Free perfume at 100 100 100 100 100 100 T = 0
Free perfume at 25.8 21.0 22.7 13.6 9.9 8.3 T = 1 day Free perfume
at 32.4 22.9 22.3 14.3 11.5 11.1 T = 5 days Free perfume at 33.0
21.2 21.7 15.9 12.5 11.9 T = 8 days Average Free 30.4 21.7 22.2
14.6 11.3 10.4 Perfume Experiment 26 27 28 29 30 31 Step
Growth:Chain 80:20 40:60 60:40 80:20 40:60 60:40 Growth
(shell:core) Core Monomer EHMA EHMA EHMA MMA MMA MMA Free perfume
at T = 0 100 100 100 100 100 100 Free perfume at 9.3 6.3 6.1 29.9
17.4 22.2 T = 1 day Free perfume at 14.5 10.9 7.9 38.3 22.9 18.1 T
= 5 days Free perfume at 12.5 12.9 7.9 41.4 24.9 16.8 T = 8 days
Average Free Perfume 12.1 10.0 7.3 36.5 21.7 19.0
[0307] As with the previous example the deficit of free perfume has
been adsorbed into the particles. It can be seen that as the level
of shell material is proportionately reduced the amount of perfume
being adsorbed increases.
Example 4
Poly(Urethane) Hybrid Mini-Emulsion Synthesis with Butyl
Methacrylate Core Cross-Linked at Various Levels
TABLE-US-00011 [0308] Experiment 32 33 34 35 36 37 poly(phenyl
3.270 3.270 3.270 3.270 3.270 3.270 isocyanate) Isophorone 6.816
6.816 6.816 6.816 6.816 6.816 Diisocyanate BMA 15 14.925 14.85 14.7
14.4 13.8 1,3 Butanediol 0.0 0.075 0.15 0.3 0.6 1.2 Dimethacrylate
AIBN 0.083 0.083 0.083 0.083 0.083 0.083 Dibutyltindilaurate 0.088
0.088 0.088 0.088 0.088 0.088 Hexadecane 1.23 1.23 1.23 1.23 1.23
1.23 SDS 1.23 1.23 1.23 1.23 1.23 1.23 1,6-Hexane Diol 3.623 3.623
3.623 3.623 3.623 3.623 1,1,1-Tris 1.290 1.290 1.290 1.290 1.290
1.290 (hydroxymethyl) propane Water 67.12 67.12 67.12 67.12 67.12
67.12
[0309] The results suggest that the addition of cross-linker to the
core does not affect perfume absorption at levels up to two mol
percent. When increasing from two to eight mol percent the level of
free perfume is doubled, indicating that the particle is less able
to adsorb perfume.
TABLE-US-00012 Experiment 32 33 34 35 36 37 Core X-linker Level 0%
0.5% 1% 2% 4% 8% Free perfume at T = 0 100 100 100 100 100 100 Free
perfume at T = 1 day 20.5 15.1 18.3 16.9 21.5 31.0 Free perfume at
T = 5 days 17.5 15.3 16.5 14.4 19.7 31.4 Free perfume at T = 8 days
17.2 14.9 16.3 14.6 19.8 37.3 Average Free Perfume 18.4 15.1 17.0
15.3 20.3 33.2
[0310] These results also show how an equilibrium between the free
perfume and the perfume in the particles is rapidly established.
Over 60% of the added perfume has been adsorbed into the particles
after the first day.
Example 5
Addition of Deposition Aid
[0311] Methyl acrylate was used as a monomer for grafting
deposition aids, due to its rate of initiation, propagation and
water solubility are best suited for this purpose. A poly(urethane)
condensation polymerisation reaction was used to graft a PET-POET
polymer to a poly(urethane) shell This was achieved by first adding
a solution of PET-POET to the encapsulate slurry to allow the
polymer to physically absorb onto the encapsulates. The PET-POET
was then permanently attached via the addition of isocyanate and
diol.
TABLE-US-00013 Poly(urethane) particle (no Poly(urethane) particle
+ Sample deposition aid) PET-POET Deposition after wash 1.7% 43.0%
Deposition after rinse 1 1.5% 39.8% Deposition after rinse 2 1.6%
34.1%
[0312] The results clearly show that with the deposition aid the
deposition of the particles onto substrate was significantly
increased.
Example 6
Incorporated Benefit Agent
TABLE-US-00014 [0313] Sample 38 39 40 41 42 43 poly(phenyl 3.86
3.86 3.86 3.86 3.86 3.86 isocyanate) Isophorone 8.05 8.05 8.05 8.05
8.05 8.05 Diisocyanate Perfume 3.2 3.2 3.2 3.2 3.2 3.2 Ethyl hexyl
8.32 acrylate Ethyl hexyl 8.32 methacrylate Butyl 8.32 Methacrylate
Benzyl 8.32 Methacrylate Methyl Acrylate 8.32 Styrene 8.32 AIBN
0.08 0.08 0.08 0.08 0.08 0.08 Dibutyltindilaurate 0.08 0.08 0.08
0.08 0.08 0.08 Hexadecane 1.23 1.23 1.23 1.23 1.23 1.23 Synperonic
A20 1.50 1.50 1.50 1.50 1.50 1.50 SDS 0.38 0.38 0.38 0.38 0.38 0.38
1,6-Hexane Diol 4.28 4.28 4.28 4.28 4.28 4.28 1,1,1-Tris 1.53 1.53
1.53 1.53 1.53 1.53 (hydroxymethyl) propane Water 67.13 67.13 67.13
67.13 67.13 67.13
[0314] A range of samples according to the invention at two
crosslinker levers (2% and 32%) were prepared using a selection of
different free radical monomers as given in the tables above.
[0315] The materials prepared were added into a non-concentrated
laundry liquid base which at 5% solids and hence a perfume level of
0.5% in the liquid base. The materials were then analysed after 1,
5 and 8 days to determine how much perfume had been leaked from the
particle into the base.
TABLE-US-00015 Experiment 41 40 39 38 Core Monomer BzMA BMA EHMA
EHA Free perfume at T = 1 day 22.5 12.7 7.4 6.0 Free perfume at T =
5 days 22.4 12.9 8.9 6.6 Free perfume at T = 8 days 21.0 14.1 8.1
5.5
[0316] Leakage can be compared with the solubility parameter value
for the core monomer. The lower the solubility parameter difference
value (Delta SP) the more compatible the fragrance is with the core
monomer. This will lead to a lower level of free perfume and hence
a lower colorimetric response when an assay is conducted. This will
translate to a lower leakage value. A correlation can be found
between solubility parameter and free fragrance.
[0317] The lowest solubility parameter value materials show the
lowest level of free perfume and conversely the highest solubility
parameter materials the highest level of free perfume.
TABLE-US-00016 Monomer Delta_SP % Free Perfume (Average) BzMA 2.27
22.0 BMA 1.77 13.3 EHMA 1.27 8.2 EHA 1.19 6.0
* * * * *