The present invention relates to A composition to reduce misting during the
coating of flexible supports
FIELD OF USE
The present invention relates to coating flexible materials or supports such as
sheets of paper or other polymeric material, either woven or nonwoven,
with a silicone composition. The present invention also relates to the
coating of flexible materials or supports with liquid compositions comprising one
or more cross-linkable polyorganosiloxanes wherein such polyorganosiloxanes are
cross-linkable by an addition reaction, a condensation reaction, a cationic reaction,
or a free-radical reaction. The present invention also relates to star branched
polyorganosiloxanes (silicone polymers) that reduce misting during the application
of the silicone composition (polyorganosiloxane) to the flexible material or
support. The flexible support may be paper, cardboard, plastic film, metal film and
the like. Some exemplary applications are paper for foodstuffs, adhesive labels,
adhesive tapes, seals and the like.
BACKGROUND OF INVENTION
The coating of flexible supports with liquid silicones is typically carried out on
coating devices that operate continuously at very high speed.
These devices usually comprise coating heads composed of several rolls, including
in particular a pressure roll and a coating roll that are continuously fed with a
silicone composition that may or may not be cross-linkable, by means of a series
of rolls that are placed next to one another. A strip of flexible support of the
desired material to be coated is fed at high speed between the pressure roll and the
coating roll to be coated on at least one of its surfaces. When it is intended to cross
link the silicone coating, apparatus to implement a cross linking reaction are
positioned downstream of the coating head. The apparatus that
2
implements cross linking may be for example an oven or an emitter of
radiation, e.g. ultraviolet (UV) radiation or an emitter of a beam of
electrons (EB).
High speed coating of flexible supports with silicones has been associated
with problems associated with the transfer of the silicone liquid (or fluid)
from the coating roll to the. flexible support, which moves forward
thro~gh the coating apparatus. One of. the particular problems associated
· with transfer of the silicone liquid from the coating roll to the flexible
support is the appearance of a fog, mist or aerosol in the immediate
vicinity of the coating head and particularly close "to the points of contact
between the coating roll and the flexible support being coated. T}1'ically,
the density of this fog, mist or aerosol increases with an increase in .the
forward speed of the flexible support being coated by the apparatus.
The first effeCt of this transfer problem is to reduc~ the amount of silicone
liquid actually transferred to the flexible support. A second effect is for
the droplets comprising the fog, mist or aerosol to condense onto the
newly coated flexible support downstream of the coating rolls creating an
orange peel. effect.. This orang~ peel effect, or coating non-uniformity,
creates problems with coverage,. the mechan~cal properties of the coating,
e.g. ruboff, and adhesion resistance.
An additional problem caused by non-uniformity in the coating is related
to industrial hygiene and the ·safety of people operating the coating
equipment who are working in the vicinity of the coating equipment.
BRIEF SUMMARY OF THE INVENTION
The present invention provides for a composition to reduce misting during
the coating of flexible supports comprising the hydrosilylation reaction
product of:
3
b) an amount a ofCH2=CHRI
where a + 1 ~ b + d + f and g ~ b, h ~ d, i ~ f with 1.5 ~b.+ d + f ~ 100;
2 ~ a + b ~ 12; 0 s c + d s 1000; 0 5. e + f S 10 and R1 is a monovalent
radical selected from the group consisting of halogens, hydrogen, Cl. to
C60 monovalent hydrocarbon radicals, Cl to C60 monovalent polyester
radicals, Cl to C60 monovalent nitrile radicals, Cl to C60 monovalent
alkyl halide radicals and. Cl to C60 monovalent polyether radicals and
mixtures thereof; where
DH = HR95i~t2i
T = R11Si0312;
and said reaction product has the formula:
M'gMaMHb-&DcD'hDHd-t. TeT'iTHr.; where
M' = (CH2CHRI)R5R6SiOt12i
D' = (CH2CHRI)R9Si0li2; and
T' = (~H2CHRI)Si0J12
. with each .R2, Rl, R4, RS, R6, R7, RS, R9 and Ri1 independently selected from
the group of Cl to C60 monovalent hydrocarbon radicals where the subscripts
a, b, c, d , e , f , g, h, and i are zero or positive subject to the limitations that b
+ d + f- g- h - i > 0.
The present invention further provides for a composition to reduce misting
during the coating of flexible supports comprising the hydrosilylation
reaction product of:
ythe
subscripts j, k, 1, m, n, o and p are zero or positive subject to the limitation
that k + m + o > 0, k + m + o < b + d 7 f- g - h - i , p ranges from 0.4 to 4.0, q
is non-zero and positive subject to the limitation that:
(b+d+f-g-h-i)/(((k+m+o)p)q) ranges from 4.59 to 0.25, where
Q = Si04t2; where
RIO is independently .. selected from. the group of C1 to C60 monovalent
hydrocarbon radicals and each RVi is independ_ently selected from the
group of C2 to ~60 monovalent alkenyl hydrocarbon radicals.
DETAILED DESCRIPTION OF THE INVENTION
The star branched siloxane compounds· of the present inventi~n are made
as the reaction product of:
in the presence of a noble metal hydrosilylation catalyst where the
subscripts a,.b, c , d , e , f , g, h, i, j, k, 1, m, n, o, p, are zero or. positive and
q is non-zero and positive, for mixtures of compounds the average values
of each of. the subscripts will most likely be non-integral, for specific
compounds the subscripts will be integral, with k + m + o > 0 and k + m +
o < b + d + f- g- h-i , p ranges from 0.4 to 4.0, preferably 0.5 to 3.0, more
preferably 0.5 to 2.5 and most preferably 0.5 to 1.5 and all sub-ranges there
between and q ranges from 1 to.200, preferably 1 to 100, more preferably 1
to 75 and most preferably 1 to 50 and alJ sub-ranges there between where
the ratio between the hydride containing precursor and the vinyl
containing precursor is defined by the following mathematical
relationship between the stoichiometric subscripts of the precursors,
(b+d+f·g·h·i)/(((k+m+o)p)q) ranges from 4.59 to 0.25, preferably from 4.5
to 0.25; more preferably from 4.5 to 0.25 and most preferably from 4.0 to
0.25and all sub:.ranges t~ere between and specifically including 3.5 to 0.25;
3.0 to 0.25; 2.5 to 0.25 an~ 2.0 to 0.25; an~ where the compound:
may be obtained by the following reaction:
MaMHbDcDHdTeTHf + aCH2=CHR1 ~ M'gMaMHt~-gOcD'hDHd·hTeT'iTI-It-i
where a + 1 s. b + d + f and g !£. b, h s. d, i s. f with 1.5 s. b + d + f s. 100; 2 s.
a + b s. 12; 0 s. c + d s. 1000; 0 .s. e + f s. 10 and Rt- is a monovalent radical
selected from the group consisting of halogens, hydrogen,, Cl to C60
monovalent ~ydrocarbon radicals, C1 to C60 monovalent polyester
radicals, C1 to C60 monovalent nitrile radicals, Cl to C60 monovalent
alkyl ~alide radicals and Cl to C60 monovalent polyether radicals ~nd
mixtures·thereof; with
OH = HR9Si02n;
M' = (CH:zCHRI)RSR6Si0112;
D' = {CH2CHRt)R9SiDl12; and
T = (CH2CHRI)Si0J12
with each R2, R3, ·R4, RS , R6, Ri', RS, R9, Rto, and R11 independently
selected from the group of C1 to C60 monovalent hydrocarbon radicals
and each RVi independently selected from the group of C2 to C60
monovalent alkenyl hydrocarbon radicals; it should be· noted t~at the
·compositions of the present invention require b + d + f - g - h - i > 0.
Methods for makil1g MQ resins; such as (MjMVikDIDVim T n J'Vio)pQ)q, are
described ·in US patent 5,817,729, US patent 5,399,614 and US .patent
2,676,1.82 herewith and hereby speci_fically incorporated by reference. The
phrase Cl to C60 is a carbon number range ranging from 1 to 60 and
includes both aliphatic and aromatic radicals, e.g. styryl, this range also
includes the following specific sub-ranges, 15 to 60, 30 to 60, 45 to 60, 1 to
1S, 1 to 30, ·1 to 45, 10 to 30, 10 to 40, 10 to 50 and all sub-ranges
therebetween.
The star branched siJicone compounds of the present invention are
described as the reaction product of the following two ~ompounds:
M'8MaMHb·gDcD'hDHd.fiTeTiTHr-i and {(MJMVikDIDVim Tn'fYio)pQ)q, because of
the multiplicity of hydrosilylation sites available for reaction on each of
the component molecules being reacted and the. difficulties of reducing
· such a stochastic chemical reaction to an analytic description.
The compositions of the present invention may be made by neat reactions
or by reactions where the reactants are diluted by solvent. Because of the
long chain nature of the substituents in these materials, neat reactions, i.e.
reactions conducted in the absence of any non-participating solvent, will
tend to produce products that conform to the molecular descriptions
herein but possessing a more entangled macro-structure. If less entangled
macro-structures of these compounds are desired, the preparative
reactions should be conducted in suitable solvent media, e.g. cyclic
siloxanes, inert hydrocarbon solvents and the like·.
Many types of noble metal catalysts for this hydrosilylation reaction are
known and such catalysts mCJ}' be used for the reaction in the present
instance. When .~ptical darity is required the preferred catalysts are catalysts
that are soluble in the r~a.ction mixture. By noble metal, Applicants define Ru,
Rh, Pd, Os, Ir, and Pt as noble ~etals and also include Ni in the definition
because of its known hydrogenation activity. Prefer~bly· the catalyst is a
platinum compound and the plat~um cort~pound can be selected from those.
having the formula (PtCI20lefin) and H(PtCl30lefin) as described in U.S.
patent number 3,159,601, hereby incorporated by reference. The olefin ~hown
in the previous two formu,as can be almost any type of olefin but is
preferably an alkenylene having from 2 to 8 carbon atoms, a cycloalkenyl~ne
have from 5 to 7 carbon atoms or· styrene. Specific olefins utilizable in the
above formulas are ethylene, propylene, the various isomers of butylene,
octylene, cyclopentene, cyclohexene, cydoheptene, and the like.
A further platinum containing material usable in the compositions of the
present invention is th~ cyclopropane complex of platinum chloride described
in U.S. patent number 3,159,662 hereby incorporated by reference.
Further the platinum containing material can be a complex formed fro111
chloroplatinic acid with up to 2 moles per gram of platinum of a member
selected from the class consisting of alcohols, ethers, aldehydes and mixtures
of the above as described in U.S. patent number 3,220,972 hereby incorporated
by reference.
The catalyst preferred for use with liquid injection molding compositions
are described in U. S. Patents numbers 3,715,334; 3,775,452; and 3,814,730
to Karstedt. Additional background concerning the art may be found at J.
L. Spier, "Homogeneous Catalysis of Hydrosilation by Transition Metals,
in Advances in Organometallic Chemistry, volume 17, pages 407 through
447, F.G.A. Stone and R. West editors, published by the Academic Press
(New York, 1979). Persons skilled in the art can easily determine an
effective amount of platinum catalyst. Generally, an effective amount for
hydrosilylation ranges from about 0.1 to 50 parts per million of the total
organopolysiloxane composition and all sub-ranges there between.
EXPERIMENTAL
By way of example, 19.9 grams ~0.083 moles) of a C16-18 alpha olefin
was mixed under a blanket of nitrogen gas with 1000 grams (. 0.21
moles) of a silyl hydride terminated polydimethylsiloxane and 10 ppm
Pt added as Karstedt catalyst. The rea~tion was heated and stirred at 95
ac for approximately four hours to allow the olefin to add to the
siloxane polymer. Quantitative chemical analysis of residual SiH
indicated that the desired amount of hydrogen had been consumed in
attaching the olefin to the siloxane·. Optionally this product may be
isolated bef9re further reaction.
5.2 grams (.05 moles) of an ((MVi)2Q)4 resin was added to the product of
the first reaction. An additional 10 ppm Pt as Karstedt catalyst was
added and the reaction stirred and heated to 95 OC: for approximately
four hours. Quantitative chemical analysis indicated that the vinyl and
hydride functional groups had reacted to the desired degree. This
product was isolated and tested as an Anti Mist Additive as reported in
Tables 1 and 2 below.
Table 1 shows examples of the synthesis of the structures of the anti
mist additi~es based on the path described above. The SiH/SiVinyl is
the ratio of moles of silyl hydrides available for reaction to the moles of
silyl vinyl available for reaction. In the compounds shown, the
SiH/SiVinyl ratio runs from 0.2 to 2.75, but a larger usable range spans
froin 0.22 to 4.5.
Table 2 shows the anti misting be~avior of the invention. Th~
measurements were made during runs on 2.5 mil SC Rhi·Liner 12 paper
using a pilot coater with a line speed of 2000 ft/minute. The paper was
coated with a standard silicone paper release formulation containmg -
2% anti mist additive with a target of 0.6 to 0.9 pounds per ream. The
mist was measured using a DustTrack Aerosol Monitor. The intake
port was positioned in the highest observed misting area thus providing
the highest expected values. The position does not reflect normal
environmental testing nor does it guarantee specific values under· all
operating conditions. The measurement is in mg of mist material pe~
cubic meter of air, the lower values being more desirable as they
· represent less misting.
The results show the anti misting materials generated for this invention
reduce the amount of generated mist at 2000 ft/min compared to the
control formulation containing no ·anti mist additive. Quite surprisingly
the mist is often reduced by a factor of greater than ten, often by about
100.
-
Table 1: Anti Mist Additive Synthesis
Example Olefin Grams ~ilyl Hydride Grams ppmPt SiH/SiVinyl gms ((Mvi)2Q)4 ppmPt
20 C16-18 19.9 MHD125MH 1000 10 2.50 .· 5.2 10
21 C30+ 48.7 MHD125MH 1000 10 2.50 5.2 10
22 C16-18 19.9 MliD125MH 1000 10 . 2.50 5.2 10
23 C16-18 37.2 MHD125MH 1500 10 2.00 8.1 10
24 C16-18 10.2 MHD125MH 500 5 1.20 5.2 5
25 C16-18 11.9 MHD125MH 600 10 1.75 4.4 5
26 C16-18 11.9 MHD125MH 600 10 2.00 3.9 5
27 C16-18 4.0 MHD125MH 200 5 2.50 1.0 5
Table 2: Anti Mist Measurements
J\MAI Mglm3 at 2000 ftlmin
rontroJ 102.00
1218 ~0 64.60
~6 ~1 10.00
lJ47 ~2 1.60
p70 ~3 . 1.73
122C ~4 1.64
384 ~5 1.13
~ ~6 ~.80
B79A 127 p.43
The foregoing examples are merely illustrative of the invention, serving to
illustrate only some of the features of the present invention. The appended
claims are intended to claim the invention as broadly as it has been conceived
and •the examples herein presented are illustrative of sele<:ted. embodiments
from a manifold of aU possible embodiments. Accordingly it is Applicants'
intention that the· appended claims are not to be limited by the choice of
examples utilized to illustrate (eatures of the present invention. As used in
the claims, the word "comprises" and its grammatical variants logically also
subtend and include phrases of varying and differing extent such as for
example, but not limited thereto, "consisting essentially of' and "consisting
of." Where neces~ry, ranges have been supplied, those ranges are inclusive
<:Jf all sub-ranges ther~ between. It is to be expected that variations in these
ranges will suggest themselves to ~ practitioner having ordinary skill in the
art and where not already dedicated to the public, those variations should
where possible be construed to be covered by the appended claims. It is also
anticipated that advances in science and technology will make equivalents
and substitutions possible that are not now contemplated by reason of the
impre<:ision of language and these variations should also ~ construed w!'ere
possible to ·be covered by the appended· claims. All United States patents
referenced herein are herewith and hereby specifically incorporated by
reference.

CLAIMS:
1. A process for the preparation of essential oil microcapsules comprising the steps
of:
a. dissolving a di- or polyisocyanate into an essential oil to obtain a mixture,
b. emulsifying the mixture of step (a) in an aqueous solution containing one of
a di- or polyamine, or a di or polyhydroxy compound and at least one
emulsifier, at a temperature in the range of ooc - 30°C, to effect
encapsulation of said essential oil through interfacial polymerization, and
adding a component to prevent or reduce microcapsule particle aggregation
to the aqueous solution in which the essential oil is dispersed, wherein the
ratio between the mole ratio of total di- or polyamine, or di- or polyhydroxyl
compound to said di- or polyisocyanate is between 0.8:1 to 1: 1.2, and
wherein the said essential oil is encapsulated together with a component
selected from an adjuvant and an agent which enhances the properties ofthe
oil,
whereby there is formed a polyurea or polyurethane film around droplets of the
essential oil, the said film enhancing the stability of said essential oil, reducing its
evaporation rate and controlling its release rate when applied to a substrate,
c. reacting the microcapsules of step (b) with reactive amine or hydroxyl
containing reagents which also contain anionic, cationic, amphoteric or hydrophilic
groups.
2. A process as claimed in claim 1 wherein the di- or polyhydroxy compound is a
di- or polyalcohol.
3. A process as claimed in claim 1 wherein said essential oil is selected from the
group consisting of cotton seed, soybean, cinnamon, corn, cedar, castor, clove, geranium,
lemongrass, linseed, mint, sesame, thyme, rosemary, anise, basil, camphor, citronella,
eucalyptus, fennel, grapefruit, lemon, mandarin, orange, pine needle, pepper, rose,
tangerine, tea tree, tea seed, caraway, garlic, peppermint, onion, rosemary, citronella,
lavender, geranium and almond and spearmint oils and mixtures thereof.
4. A process as claimed in claim 1 wherein said encapsulation is carried out at
ambient conditions by dissolving a polyisocyanate into said essential oil, emulsifying the
resulting mixture in an aqueous solution containing a polyamine and/or a di- or
-3ftpolyalcohol
wherein a preliminary reaction occurs which forms a membrane and
consumes any ofthe polyamine present, and the slower reacting polyalcohol then reacts
and forms an exterior crosslinked coating, and any remaining isocyanate is further
consumed by water to form amine which reacts with any remaining isocyanate.
5. A process as claimed in claim 1 wherein said di- or polyisocyanate is chosen
from the group consisting of dicyclohexylmethane 4,4' -diisocyanate, hexamethylene I ,6-
diisocyanate, isophorone diisocyanate; trimethyl-hexamethylene diisocyanate, trimer of
hexamethylene 1 ,6-diisocyanate, trimer of isophorone diisocyanate, I ,4-cyclohexane
diisocyanate, 1 ,4-( dimethylisocyanato) cyclohexane, biuret of hexamethylene
diisocyanate, urea of hexamethylene diisocyanate, trimethylenediisocyanate, propylene!
,2-diisocyanate, butylene-1 ,2-diisocyanate mixtures of aliphatic diisocyanates, aliphatic
triisocyanates, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene
diisocyanate, 4-(isocyanatomethyl)-1 ,8-octyl diisocyanate, aromatic polyisocyanates, 2,4-
diisocyanate, 2,6-toluene diisocyanate, naphthalene diisocyanate, diphenylmethane
diisocyanate, triphenylmethane-p,p' ,p" -trityl triisocyanate, aromatic isocyanates, toluene
diisocyanate, polymethylene polyphenylisocyanate, 2,4,4' -diphenyl ether triisocyanate,
3,3' -dimethyl-4,4' -diphenyl diisocyanate, 3,3' -dimethoxy-4,4' diphenyl diisocyanate, 1,5-
naphthalene diisocyanate, 4' ,4" -triphenylmethane triisocyanate, and isophorone
diisocyanate .
6. A process as claimed in claim 1 wherein said diamine or polyamine is selected
from the group consisting of ethylenediamine, diethylenetriamine, propylenediamine
Tetraethylenepentaamine, pentamethylene hexamine, alpha, omega-diamines, propylene!
,3-diamine, tetramethylenediamine, pentamethylenediamine and 1,6-
hexamethylenediamine polyethyleneamines, diethylenetriamine, triethylenetriamine,
pentaethylenehexamine, 1 ,3-phenylenediamine, 2,4-toluylenediamine, 4,4'-
diaminodiphenylmethane, 1,5-diaminoaphthalene, 1 ,3,5-triaminobenzene, 2,4,6-
triaminotoluene, 1 ,3,6-triaminonaphthalene, 2,4,4' -triaminodiphenyl ether, 3,4,5-
triamino-1 ,2,4-triazole, bis(hexamethylentriamine) and 1 ,4,5,8-tetraaminoanthraquinone.
7. A process as claimed in claims 1 and 2 wherein said di- or polyalcohol is
selected from the group consisting of polyhydric alcohols, such as ethylene glycol,
diethylene glycol, propylene glycol, 1 ,4-butane diol, 1,4 hexane diol, dipropylene
glycol, cyclohexyl 1,4 dimethanol, 1,8 octane diol and polyols such as poly(ethylene
glycols), poly(propylene glycols), poly(tetramethylene glycols) with average molecular
-49-
weights in the range of 200-2000, trimethylolpropane, glycerol, hexane, triols and
pentaerythrytol, 1 ,3-phenylenedihydroxy, 2,4-toluylenedihyroxy, 4,4'dihydroxydiphenylmethane,
1 ,5-dihydroxyoaphthalene, 1 ,3,5-trihydroxybenzene, 2,4,6-
trihydroxytoluene, 1 ,3,6-trihydroxynaphthalene, 2,4,4' -trihydroxydiphenyl ether and
polyvinyl alcohols.
8. A process as claimed in claim 1 wherein a component to prevent or reduce
microcapsule particle aggregation is selected from the group consisting of an emulsifier,
a suspending agent, or a steric barrier polymer is added to the aqueous solution into
which the essential oil mixture is dispersed, said component being chosen from the
group consisting of sodium, potassium, magnesium, calcium or ammonium salts of
lignin sulfonate; low and high density polyvinylalcohol, or polysorbate 20, 40 or 80
carboxymethyl cellulose, sodium salt, Xantan gum, Karya gum and Locust bean gum
polyvinylpyrrolidone (PVP), water soluble polyvinyl alcohol (PV A) and
poly(ethoxy)nonylphenol, polyether block copolymers, polyoxyethylene adducts of
fatty alcohols and esters of fatty acids.
9. A process as claimed in claim 1 wherein the reactive amine or hydroxyl
containing reagents containining anionic or cationic or amphoteric or hydrophilic
groups render the surface of the encapsulated essential oil microcapsules anionic,
cationic or amphoteric or hydrophilic but non-charged.
10. A process for forming microcapsules of essential oils as claimed in claim
wherein the said microcapsules possess sustained antimicrobial activity and adaptably
anti viral and anti fungal activity when used in hard surface cleaners, laundry detergents
and softeners.