Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02202897 2004-12-17
67369-624
_ 1
LOW VOC HAIR SPRAY RESIN COMPOSITIONS
CONTAINING HOMOGENEOUS TERPOLYMIERS 0O~
VINYL PYRROLIDONE, VINYL CAPROLACTAM
AND N-(~- DIMETHYLAMINOPROPYL1METHACRYLAMIDE
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to low VOC hair spray
resin compositions, and, more particularly, to
substantially homogeneous terpolymers of vinyl
pyrrolidone (vP), vinyl caprolactam (VCL) and
N-(3-dimethylaminopropyl)methacrylamide (DMAPMA) as the
hair fixative therein.
2. Description of the Prior Ark
U.S. Patent 5,158,762 disclosed hair spray
compositions containing terpolymers obtained by one-pot
polymerization of vinyl pyrrolidone, vinyl caprolactam
and dimethylaminoethyl methacrylate (DMAEMA) (e. g.
GAFFIX~ VC-713, supplied by International Specialty
Products). The monomer 3-(N-dimethylaminopropyl)
methacrylamide was considered as a suitable ammonium
derivative to replace dimethylaminoethyl methacrylate in
the terpolymer, however without further description.
This invention
provides a solution of a substantially homogeneous
terpolymer of VP, VCL and DMAPMA monomers, in a defined
composition, which is clear and low in viscosity, which
forms a spray of relatively small particle size, and is
an effective fixative resin for a 55% VOC hair spray
composition having effective curl retention properties.
CA 02202897 2004-12-17
67369-624
- 2 -
The invention also provides a
clear, low viscosity solution of a substantially
homogeneous terpolymer of VP, VCL and DMAPMA, in a
predetezmined composition, which is made by a homogeneous
polymerization process.
pEFINITIONS
(1) The active fixative resin of the invention is a
substantially homogeneous terpolymer of 1-20 wt. %,
preferably 5-15 wt. %, of vinyl pyrrolidone (VP), 60-95
wt. %, preferably 80-90 wt. %, of vinyl caprolactam (VCL)
and 1-10 wt. %, preferably 2.5-7.5 wt. %, of
N-(3-dimethylaminopropyl)methacrylamide (DMAPMA), which
is made by a process of homogeneous polymerization.
(2) The homogeneous polymerization process of the
invention comprises precharging VCL in a reactor,
optionally with a predetermined small amount of VP and/or
DMAPMA, suitably less than 15%, and introducing VP and
DMAPMA incrementally into the reactor at a predetermined
feeding schedule so that the rate of disappearance of
both VP and DMAPMA substantially~coincides with the rate
of disappearance of VCL during the polymerization.
(3) The hair spray concentrate of the invention is
the homogeneous terpolymer resin in an aqueous, aqueous-
alcoholic or alcoholic solvent wherein the concentration
of the terpolymer is between about 10 and about 70 wt. %,
preferably 35-55 wt. %.
(4) The 55% VOC (volatile organic compounds) pump
spray composition of the invention is a solution or
suspension of'the homogeneous terpolymer containing 1-10%
solids, preferably 3-5% solids, in 55% or less alcohol,
preferably ethanol, the rest water and adjuvants,
preferably including a corrosion inhibitor.
CA 02202897 1997-04-16
WO 96119971 PCT/US95lI6667
- 3 -
(5) The 55% VOC aerosol hair spray composition is
the 1-10% solids, preferably 2-4% solids, composition of
the homogeneous terpolymer with 20 wt. % or less alcohol,
preferably ethanol, and 35 wt. % or less of propellant,
preferably dimethyl ether (DME), and a neutralizer and
other adjuvants, preferably including a corrosion
inhibitor.
SUMMARY OF THE INVENTION
In accordance with the invention, there is
provided herein:
A. An improved hair fixative resin which is a
substantially homogeneous terpolymer comprising, by
weight, 1-20%, preferably 5-15%, of VP; 60-95%,
preferably 80-90%, of VCL; and 1-lU%, preferably
2.5-7.5%, of DMAPMA.
B. A homogeneous polymerization process for making
the homogeneous terpolymer of the invention. In this
process the slowest reacting monomer of the terpolymer
(VCL) is precharged, optionally with small amounts of VP
and DMAPMA, and the faster reactincf monomers (VP and
DMAPMA) are introduced incrementally into the reactor at
a predetermined feeding schedule so that the rate of
disappearance of VP and DMAPMA monomers substantially
matches the rate of disappearance of VCL during the
polymerization.
~ C. A solutir~n of the substantially homogeneous
terpolymer of the invention which is crystal clear (Hach
value of less than 10 NTU, preferably less than 1 NTU),
and has a low viscosity (less than 300,000 cps,
preferably less than 100,000 cps).
CA 02202897 2004-12-17
67369-624
- 4 -
D. A 55% VOC hair spray resin composition containing
2-10 wt. o of the homogeneous terpolymer having an effective
spray pattern, a particle size of 85 microns, and a
desirable high humidity curl retention property.
In one aspect, the invention provides a
homogeneous polymerization process for forming a clear
solution of a hair fixative resin which is a homogeneous
terpolymer of vinyl pyrrolidone (VP), vinyl caprolactam
(VCL) and N-(3-dimethylaminopropyl)methacrylamide (DMAPMA)
monomers, in a compositional range of 60-95% VCL, 1-20o VP
and 1-10% DMAPMA, by weight in alcohol or water, or mixtures
thereof, at a solids content of 10-70%, having a clarity of
less than 10 NTU, and a Brookfield viscosity of less than
300,000 cps, at a polymerization temperature of about 65°C,
for about 5 hours, in the presence of a radical initiator at
a pH of about 7.5, which consists of the steps of: (a)
charging a reactor with VCL, optionally with an amount of
VP, DMAPMA or a mixture thereof; and (b) introducing VP and
DMAPMA incrementally into the reactor, wherein the rate of
disappearance of VCL, VP and DMAPMA are matched during the
polymerization.
IN THE DRAWINGS
FIGURE 1 is a graphical representation of a non-
homogeneous (one-pot) polymerization process in which is
plotted percent unreacted vinyl caprolactam (VCL), vinyl
pyrrolidone (VP) and dimethylaminopropyl methacrylamide
(DMAPMA) vs. time for a reaction mixture of Example 1 below.
FIGURE 2 is a similar plot as FIGURE 1 for the
homogeneous process of the invention according to Example 2
below.
CA 02202897 2004-12-17
67369-624
- 4a -
DETAILED DESCRIPTION OF THE INVENTION
DETERMINATION OF ADDITION SCHEDULES FOR VP AND DMAPMA TO
FORM A HOMOGENEOUS TERPOLYMER WITH VCL
A. First, a one-pot polymerization of VCL, VP and
DMAPMA monomers was carried out as follows:
F'Y11MDT.T,' 'I
Vinyl caprolactam (591.43 g), vinyl pyrrolidone
(55.57 g), dimethylaminopropyl methacrylamide (DMAPMA)
(42.56 g) and ethanol (842.8 g) were charged into a 2-liter
water-jacketed resin flask. The reaction flask was equipped
with a condenser, a thermometer, a septum (for catalyst
addition), an anchor type metal stirrer,
CA 02202897 2004-12-17
67369-624
- 5 -
and a nitrogen sparge tube. Nitrogen was bubbled through
the solution while the resin flask was heated using hot
water circulating through the jacketed flask. After the
temperature of the solution reached 68°C., an additional
half-hour was allowed before the first Lupersol 11 (0.25
ml) was injected into the flask. Subsequently, Lupersol
11 additions were made at l0, 40, 70, 100, 140 and 180
minutes after the first addition. The reaction
temperature was brought up to 74°C. and two shots of
Lupersol 554 M75 (0.25 ml) were added at 240 and 330
minutes. The contents were allowed to react for an
additional five hours at 74°C. and then cooled to
35-40°C. After being neutralized with 12.25 g of
concentrated sulfuric acid, the product was discharged.
The relative percentage amounts of residual
monomers present during the course of the one-pot
reaction was determined by gas chromatographic analysis
after sampling the reaction mixture periodically. The
analytical data obtained then was plotted as the graph of
FIGURE 1.
'" As shown in FIGURE 1, the VP and DMAPMA
monomers react much more rapidly than VCL. Accordingly,
after 100 minutes, for example, all the VP and DMAPMA
monomers are consumed while residual VCL monomer still is
available for homopolymerization. Thus the terpolymer
formed is of a composition different from the desired
monomer ratios selected by the precharged amounts of the
two monomers. Under these experimental conditions, the
polymer product obtained is a complex mixture of a
homopolymer which is polyvinyl caprolactam, various
copolymers, and a terpolymer of VCL, VP and DMAPMA of
uncertain composition.
CA 02202897 1997-04-16
WO 96/19971 PCT/US95/16667
- 6 -
_B. To form a homogeneous terpolymer, it is
necessary that the curve of rate of reaction vs. time for
both VP and DMAPMA substantially coincide or match the
rate of reaction curve for VCL. To accomplish this, the
VCL is precharged and substantially all the VP and DMAPMA '
monomers are fed external to the precharge at a feeding
schedule determined by analysis of the data of FIGURE 1.
The ~ VP and DMAPMA monomers to be fed at time t of the
polymerization is determined from the Asymmetric Double
Sigmoidal Distribution formula, At, below, which has four
adjustable parameters, al, a2, a3 and a4 .
1 1
At = 1 -
a2 a2
1 + exp al - - t 1 + exp al + - t
2 2
a3 a4
where t = time in minutes during copolymerization;
al~is a parameter which determines the center
of the distribution;,
a2 is a parameter which affects the width of
the distribution;
a3 is a parameter which determines the
ascending portion of the distribution; and
a4 is a parameter which determines the
descending portion of the distribution.
VP or DMAPMA to be f ed at time t = ~ x loo
At
t = 0
where N = time when the polymerization is completed.
CA 02202897 1997-04-16
WD 96119971 PCTJITS95126667
- 7 .
To match the VP and DMAPMA curves to the VP
curve of FIGURE 1, an "initial guess" is made for the
values of al, a2, a3 and a4 for each of these monomers.
Then these values are inserted into the At formula and
the % VP and DMAPMA to be fed at time t is calculated.
The resulting % unreacted VP and DMAPMA during this
polymerization will probably not match the % unreacted VP
at the same time t. If the % unreacted VP or DMAPMA at
time t is too large, then the value of a3 (ascendency) in
the At formula is increased, a4 (descendency) is
decreased, al (center) is decreased, and a2 (width) is
decreased. Conversely, if the initial guess values of al
through a4 give a reaction rate for VP or DMAPMA which is
too fast, then changes in the values of al through a4 are
made in a direction opposite to those discussed above.
These new values of the parameters are then
used to determine a new feeding schedule. Using this
feeding schedule, another polymerization is carried out,
and the process of adjustment of the parameters described
above is repeated.
This process is known as °'interative fitting"
of data to a curve. After 4 or 5 such iterative
fittings, the experimental VCL, VP and DMAPMA curves will
be matched, as shown in FIGURE 2 herein.
The matched curves of VCL, VP and DMAPMA in
FIGURE 2 will have at least one set of values for al, a2,
a3 and a4 (the last set of the iterative fitting process)
for suitable feeding of VP and DMAPMA over the entire
period of polymerization. One such set is:
VP DMAPMA
al = 1 al = 32
a2 = 10 a2 = 50
a3 = 1 a3 = 15
a4 = 30 a4 = 75
CA 02202897 1997-04-16
WO 9G/19971 PCTlUS95/16667
- g -
_C, With such schedules available, a homogeneous
terpolymer of VCL, VP, and DMAPMA can be prepared as
described in Example 2 below.
r
EXAMPLE 2
Pret~aration of a Homoaeneous Tert~olvmer of
85% VCL. 10% VP and 5% DMAPMA
Vinyl caprolactam (VCL) (602.1 g - 100%), vinyl
pyrrolidone (28.1 g - 50.4%), DMAPMA (4.38 g - 10.1%) and
ethanol (858 g) (45% solids) were charged into a 2-liter
resin pot equipped with a gas inlet, a liquid inlet, a
thermometer and a condenser. The pH of the solution was
adjusted to about 7.5 with KOH. Then a stream of
nitrogen is introduced which bubbles through the solution
during the reaction. The solution was gradually heated
to 65°C. Then VP (63.2 g) and DMAPMA (51.4 g) were
introduced incrementally into the pot with vigorous
stirring over a period of 5 hours so that the relative
concentrations of the monomeric VCL, VP and DMAPMA
monomer remained practically constant throughout the
reaction at predetermined levels.
As soon as VP and DMAPMA are introduced to the
pot, Lupersol 11 (t-butylperoxy pivalate in mineral
spirits) catalyst is added. The rate of the addition of
the catalyst is such that 2 ml of Lupersol is completely
delivered in 4 hours. The solution is held for an
additional 3 hours at the 68°C. The product is an
alcoholic solution of the homogeneous terpolymer of VCL,
VP and DMAPMA.
180 g of the polymer solution then was
transferred to a 2-liter flask and 500 g of distilled
water was added. The resulting solution then was
stripped under reduced pressure at 40-50°C. on a rotovap
to remove 200 g of solvent (ethanol/water). A clear
viscous polymer solution in water was obtained.
The sequence and mode of addition of monomers
during the process is summarized in Table 1 below and the
plot in Figure 2.
CA 02202897 1997-04-16
WO 96119971 PCT/US951t6667
g _
A
N O Ine-Ie-i1G 00O ll1P O O O
O
O 1n 01In I~V' e-1v-isrM O ~O O
O
,..I . . . . . . . . . . . In r-1
r-I
1(j~ M l~ N N CON InI~ CO81 O .-1
.V 01r1 M et'd'tn l!1l17InlW 0
O O ~rw totn tmn tnm n um n
~I.-i~I.--I.-1.-I~1
0
~
N ~ O O O O O O O O O O O CO O
t~
11-rltn O (n O
d~
.
a a 3..1co
p V N o 0 t
n
,, a .
-~1Irlw ao
A
N
W ~ r-IM
b
G4 H O O O O O O O O ~ O ri O
M
ri ~G
M
O ~ ~
V N N 00
O
O M
Wit'
~i
H ml
r
H ~ U O r101 d'O O N H t0d' ~ t0 M COC~
ri ~ t~10 lI1O d' O G~ O d' O1~D M I~N
H
'''i -I ~ d'CO COI~ tn d'N N .r-i~ O M N O
'W ~ r ~ . d'
.,
Ca
.,..I ,J H
r1
O
~
N
dP H M
.F.,M
d~ w
N d' O r-1r1 O O O O O O ~O M r-i
_ O r-1d'I~ N 01 r-1O O O O O O 111 1001 O
. . . . . . . . . . . ' ~
..
t~In I~N f-IO O O O ~ O ~ M r1 O
N H ~
.J~ .-1
U
..p.,
II ..
o O O O o 0 o t1s
. O O O N LnCO r1d' h O
O O M 1001 v-ir1r1 N N N M
~ ~ 1 I 1 1 1 I 1 1 I 1 r1 -rl
-rir1 O O O O O O O O o O t~ ~ ~ N
H ~ M ~ ~ 3
~ ri v-1N N N O N
H dada G1
CA 02202897 1997-04-16
WO 96/19971 PCT/LTS95I16667
- 10 -
EXAMPLE 3
Preparation of a Homogeneous Ternolymer of
55% VCL 40% VP and 5% DMAPMA '
Vinyl caprolactam (VCL) (414.9 g - loo%), vinyl
pyrrolidone (1065 g - 44.2%), DMAPMA (0.67 g - 1.5%) and
ethanol (858 g) were charged into a 2-liter resin pot
equipped with a gas inlet, a liquid inlet, a thermometer
and a condenser. The pH of the solution was adjusted to
about 7.5 with KOH. Then a stream of nitrogen is
introduced which bubbles through the solution during the
reaction. The solution was gradually heated to 65°C.
Then VP (63.2 g) and DMAPMA (51.4 g) were introduced
incrementally into the pot with vigorous stirring over a
period of 5 hours so that the relative concentrations of
the monomeric VCL, VP and DMAPMA monomer remained
practically constant throughout the reaction at
predetermined levels.
As soon as VP and DMAPMA are introduced to the
pot, Lupersol 11 (t-butylperoxy pivalate in mineral
spirits) catalyst is added. The rate of the addition of
the catalyst is such that 2 ml of Lupersol is completely
delivered in 4 hours. The solution is held for an
additional 3 hours at the 68°C. The product is an
alcoholic solution of the homogeneous terpolymer of VCL,
VP and DMAPMA.
CA 02202897 1997-04-16
WO 96119971 PCT'liJS951~6667
- 11 -
O N e-iN N \OV~ M CO 01O O O O
1~N CO d'01 I~M 01h O O ~G O O
-~
~ fd-1 e-iCO M COri 01M 10t'~01O ri
7 .a.1 t0tf1O N cr c~'LC71nl!)L7to
!l7 O M ~' In InIt1Intt7In!f7!t7ll7
lL~ H r-Ir1 r-1r-Iw-1<ir-1.-~e-i.-1e-~
.,..I
O .1.1O
M ~ .~ O x O O O O O O .O O O O O 00 O O
W ~~-~ o ~ In o r-I
U N ~ .~ t,~n ~ InN
"JQ N W 00 IIWG
W ~ ~ O
N PG ~ ':~ N O O O O O O O O O O N O M
f~ A O . l -I ~ 01 l0O
~-
W W ~ ~ ~ ~ d' tGO
~ .r11(1, ~, ~ N M
~
D
H U N !L7O I~tn G1M COCO O Op tL~~p tn
D C 'r-Ih t~ ~ ~ r co .-ioD t~a wro~ .~o~ O
W -~~ ~ , --1
fs, U7N r~ '~"O 1G~ CO~D InM N v-1r-IO lDN O
'a' i
W ',
CT
d'
O O M O O O O O M r1 M
O ~ n 1 0 !' N ~ pv
01 I~1n l~CO 00O O O O O 01d' >T
CO O
V 1D N O O O O O O lf1 d~
d'ri l~O
N
.. a,
r.pa
p
0 0 0 0 0 0 0
O O O " ..
O N !n00 v-ia~ ~ O
7 M ~D p1ri r1r1 N N N M v~
~..' 1 1 J 1 1 I 1 1 I I I 3 r~
'rir1 O O O O O O O O O O ~
C~ ~ M 1001 N In COv-isTl~ O
~ N N N O P
H P p
CA 02202897 1997-04-16
'rJVO 96/19971 PCT/US95/16667
- 12 -
EXAMPLE 4
Preparation of a Homogeneous Tert~olvmer of
55% VCL 40% VP and 5% DMAPMA
Vinyl caprolactam (VCL) (511.5 g - 100%), vinyl
pyrrolidone (64.5 g - 44.2%), DMAPMA (0.65 g - 1.5%) and
ethanol (858 g) were charged into a 2-liter resin pot
equipped with a gas inlet, a liquid inlet, a thermometer
and a condenser. The pH of the solution was adjusted to
about 7.5 with K~H. Then a stream of nitrogen is
introduced which bubbles through the solution during the
reaction. The solution was gradually heated to 65°C.
Then VP (63.2 g) and DMAPMA (51.4 g) were introduced
incrementally into the pot with vigorous stirring over a
period of 5 hours so that the relative concentrations of
the monomeric VCL, VP and DMAPMA monomer remained
practically constant throughout the reaction at
predetermined levels.
CA 02202897 1997-04-16
W O 96/19971 PCT/US95116667
- 13 -
In Q1N 01CO COlf~1Dtf1e-1O O O
O
tL1O N O tf1O lf)O CO ri O t0 O
O
-.1 . . LW --I
r-1
Id lf1d'tl7M M O M \Ot' C1 O v-1
S.I
M 00r1 M d' LC)In LnLfIlf1l0
O d' d'tn !ntn tnlf1lf7tf1lf1tn
ri e~r-ie-1r-1r-Ir1 r1r1 r-1r-1
f~ W O O O O O O O O O O O CO O !~
n -~ o x o ~ o r
m o s~
> .~I ° w o0
10O O O O O O O O O O t0 01
M
d' d' I~
t0
. ,
,
p
H J A\
p
H - U O d' 00O d'M ri01 N ~DIn O t~In
.1'"."-r1~ ~ (~M O tl710o I~10 01 M C1 !~ COO
W -,,.i~ p,,.-I
.
w .1J~ )~ O t0 O CO toIn M N r~lr1O ~d' N O
f~ N O ,-.i
'a~ Ca
~
O m
N
r1M
.~.,M
N 00 G1~O d'tf1O O O O O d' lf1~D \ C1
O101 CO(t)e-~(~ O O O O O CO M lf7LT
O
N O O 01 d'e-1O O O O O In C1d' d'
fCf ~ ~ ~' N d' O ..
-1
U
..a,
o ~ G1
f~ II ..
O O O O O O O Is
O O O N In CO~-1d' t~O v .1~'J~
,
O O M t~01 ~-Ir-1~-1N N N M ~ ~J
I I I 1 1 I 1 I 1 I r1 -r-1
-rl-r-I O O O O O O O O O O I~ ~ U~
E'~-~. M tD ~ N ~ ~
"y -ie-IN N N O dl
',
H dPdP D
CA 02202897 1997-04-16
WO 96/19971 PCT/US95/16667
- 14 -
HAIR CARE COMPOSITIONS
In a water-based, rinse-off, hair styling and
conditioning composition, the homogeneous terpolymer of
the invention comprises about 0.2-20%, preferably 1-10%,
and, most preferably, about 2-8%, by weight of the hair
care product, the rest being water, and, optionally
including an organic solvent such as ethanol, and/or
other acceptable adjuvant components such as corrosion
inhibitors, silicones, surface active agents, viscosity
modifiers, dyes, chelating agents, distributing aids,
pearlescent aids, opacifiers, perfumes, fatty alcohols,
pH adjusting agents, and the like. Particularly
desirable are corrosion inhibitors.
The homogeneous terpolymer of the invention
also finds particular utility in multifunctional hair
care products such as water-based, rinse-off hair styling
and conditioning products, and in leave-on hair care
products such as a mousse, and may be included as a
concentrate, or as a gel, and applied as a self-actuated
pump hair spray, or in an aerosol product with a
propellant. Various actuator and packaging devices known
in the art may be used therewith.
PROCEDURE FOR PREPARING HAIR SPRAY
COMPOSITIONS OF INVENTION
A. Pump S ra
The pump hair spray compositions of the
invention were prepared by first dissolving the
homogeneous terpolymer resin in ethanol and adding the
requisite amount of water. The composition then was
packaged into a high density polyethylene bottle fitted
with a suitable pump actuator, e.g. a pump sprayer
(160 ml) with 0.018 x 0.010 inch deep actuator (SEAQUIST
EUROMIST II).
CA 02202897 1997-04-16
WO 96!19971 PCTlUS95/~6667
- 15 -
B. Aerosol S ra
The aerosol hair spray resin compositions of
the invention were prepared from 65% by weight of the
hair spray concentrate, a vapor phase inhibitor, a liquid
phase inhibitor, adjuvants where needed, and 35% by
weight of a propellant, e.g. dimethyl ether.
INVENTION EXAMPLES 5-8
The following hair spray compositions of the
invention were prepared in a stainless steel mixing
vessel and mixed at ambient temperature for 20 minutes
with a turbine agitator.
TABLE 4
HAIR SPRAY COMPOSITIONS
Example No 5 6 7 8
Component Wei ght %
Homogeneous Terpolymer 8.90 6.67 8.90 6.67
of Ex. 2 (45% active
in
ethanol)
Water 41.00 42.00 40.50 41.50
Adjuvants 0.50 0.50
Propellant 35.00 35.00
Ethanol 50.10 51.33 15.10 16.33
100.00 100.00 100.00 100.00
COMPARATIVE EXAMPLE 9
°' The following comparative hair spray
composition was prepared in the manner set forth above.
CA 02202897 1997-04-16
VVO 96/19971 PCT/US95/16667
- 16 -
TAELE 4
EXAMPLE NO. 9
Component Weiq~ht
Non-Homogeneous
Terpolymer of Ex. 1
(45~ active in ethanol) 8-90
Water 41.00
Ethanol 50.10
HAIR SPRAYPROPERTIES
INVENTION VS. COMPARATIVE EXAMPLE
Homogeneous Non-Homogeneous
Composition Composition
iLEx. 5~, ~Ex. 9)
Turbidity (HACH) 0.6 40.1
HHCR (90 min) 88.6 84.2
(4 hr.) 76.6 75.3
Particle size, DAV 0.5] 85.3 95.3
[V,
Stiffness 8.3 6.7
Curl snap 9.0 6.7
Curl memory 7.7 4.0
While the invention has been described with
particular reference t~ certain embodiments thereof, it
will be understood that changes and modifications may be
made which are within the skill of the art. Accordingly,
it is intended to be bound only by the following claims,
in which:
f
