STAR-BRANCfiED SILICONS POLYMERS AS ANTI -MIST ADDITIVES FOR COATING APPLICATIONS
HELD OF USE
The present invention relates to coating flexible materials or supports such as sheets of paper or other polymeric material, either woven or non-woven, 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 THE 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 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 through 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. Typically, 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 reduce 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 orange peel effect, or coating non-uniformity, creates problems with coverage, the mechanical 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.
SUMMARY OF THE INVENTION
The present invention provides for a composition comprising the hydrosilylation reaction product of:
Vompound A + a
where the subscripts a, (3, y, 6, § , and X are zero or positive and (5 + 5 + \ > 2, and the stoichipmetric coefficient a has a value of such that ((p+6+X) / ((b+d+f)-(g+h+i )-(k+nn-o))) is 0.01 to 10 where Compound A is the reaction product of:
M1BMaMHb.gDcDl,1DHd.hTeT1iTHf,i and ((MjMVikDiDVimTnTVi0)pQ)q/
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
OwithL53/2; Q = SiO4/2;
M1 = (CH2CHRi)R5R6SiOi/2; D' = (CH2CHRi)R9SiO2/2; and T1 = (CH2CHR1)SiO3/2
with each R2, R3, R4, R5 , R6, R7, R8, R9, R10, and R^1 independently selected for each molecular species from the group of Cl to C60 monovalent hydrocarbon radicals and each RVi independently selected from the group of C2 to C60 monovalent alkenyl hydrocarbon radicals.
The present invention further provides for a process to reduce misting in the coating of a flexible substrate said process comprising preparing a coating composition for coating said substrate and adding thereto the compositions of the present invention.
DETAILED DESCRIPTION .OF THE INVENTION
"*The star branched siloxane compounds of the present invention are made as the hydrosilylation reaction product of:
compound A + oc (MaMVipDrDVi6T,j,TVix) where the subscripts a, fi, % 5, § , and X are zero or positive and |3 + 5 -f A, > 2, 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, and the stoichiometric coefficient a has a value of such that ((JJ+5+X) / ((b+d+f)-(g+h+i Hk+m-fo))) is 0.01 to 10, preferably 0.01 to 5, more preferably 0.10 to 5 and most preferably 0.2 to 1.0 where Compound A is the reaction product of:
M'gMaMHb.gDcD1hDHd.hTeT1iTHf.i and ({MjMVikDiDVWTnTVio}^,
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 + p0 with 1.5 < b + d + f < 100;
22, and the stoichiometric coefficient a has a value of
such that ((B a, B+S+A)/((b+d+f)-(g+h+i)-(k+m+o))) is 0.01 to 10
where Compound A is the reaction product of:
b. M'gMaM Hb-gDcD'hDHd-hTeTiT'Hf-i and ((MjMVikD1DVimTVinTVio)pQ)q- in
the presence of a noble metal hydrosilylation catalyst where the
subscripts a, b, c, d, e, f, g, h, i, j, k, I, 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 MgMaMHb.gDcD1hHd.hTeT1THf-i
f. where the stoichiometric coefficient B satisfies the following
relationship: β + 1 ≤ b + d + f and b + d + f-g-h-i->0 with 1.5
≤b + d + f ≤ 100;
g. 2≤a + b≤12;0≤c + d≤10000; 0 ≤ e + f ≤10 and R1 is a
monovalent radical selected from the group consisting of
halogens, hydrogen, C1 to C60 monovalent hydrocarbon radicals,
C1 to C60 monovalent polyester radicals, C1 to C60 nonovalent
nitrite radicals, C1 to C60 monovalent alkyl halide radicals and C1
to C60 monovalent polyether radicals and mixtures thereof; with
h. M = R2R3R4SjO1/2;
i. MH = HR5R6SiO1/2;
j. Mvi = RViR5R6SiO1/2;
k. D = R7R8SiO2/2;
I. DH = HR9Si02/2;
m. Dvi = RviR10SiO2/2;
n. T = R11SiO3/2;
o. TH = HsiO3/2;
p. Tvi = RviSiO3/2;
q. Q=SiO4/2;
r. M' = (CH2CHR1)R5R6SiO1/2; and s. D'=(CH2CHR1)R9Si02/2; t. T'= (CH2CHR1)R9Si03/2;
u. with each R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 independently selected for each molecular species from the group of C1 to C60 monovalent hydrocarbon radicals and each RV| independently selected from the group of C2 to C60 monovalent alkenyl hydrocarbon radicals.
2. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 1 wherein R1 a is selected from the group consisting of C15 to C60 monovalent hydrocarbon radicals, C15 to C60 monovalent polyester radicals, C15 to C60 monovalent nitrite radicals, C15 to C60 monovalent alkyl halide radicals, C15 to C60 monovalent polyether radicals and mixtures thereof.
3. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 1 wherein R1 a is selected from the group consisting of C30 to C60 monovalent hydrocarbon radicals, C30 to C60 monovalent polyester radicals, C30 to C60 monovalent nitrite radicals, C30 to C60 monovalent alkyl halide radicals, C30 to C60 monovalent polyether radicals and mixtures thereof.
A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 1 wherein R1 a is selected from the group consisting of C10 to C40 monovalent hydrocarbon radicals, C10 to C40 monovalent polyester radicals, C10 to C40 monovalent nitrite radicals, C10 to C40 monovalent alkyl halide radicals, C10 to C40 monovalent polyether radicals and mixtures thereof.
5. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 2 where each R2, R3, R4, R , R6, R7, R8, R9, R10, and R11 are methyl.
6. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 3 where each R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are methyl.
7. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 4 where each R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are methyl.
8. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 1 wherein R1 is styryl.
9. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 7 where each R2, R3, R4, R5 R6, R7, R8, R9, R10, and R11 are methyl.
10. A star branched silicone polymers being a hydrosilylation reaction product as claimed in claim 7 where each R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are selected from the group consisting of C30 to C60 monovalent hydrocarbon radicals, C30 to C60 monovalent polyester radicals, C30 to C60 monovalent nitrite radicals, C30 to C60 monovalent; alkyl halide radicals, C1 to C60 monovalent polyether radicals and mixtures thereof.
11. A star branched silicone polymers being a hydrosilylation reaction product as claimed in anyone of claims 1 to 10 used in a composition to reduce misting during the coating of flexible supports.