CA2381514A1 - Process for preparation of rubber silica masterbatches based on the use of polymer latices - Google Patents

Abstract

The present invention relates to a filled polymer masterbatch based on polymers derived from latices, and to a process for preparing it. In one of its embodiments, the present invention relates to the hydrophobicizing of particles, particularly mineral particles that are hydrophilic and have surface hydroxyl groups, for example, silica, silicates, clay, alumina, titanium dioxide and the like. The invention also extends, however, to treatment of non-mineral particles, for instance carbon black. In another of its embodiments, the present invention also relates to a filled, particularly silica-filled, polymer latex. In yet another embodiment, the invention relates to a silica-rubber masterbatch, and to a process for preparing it.

Description

Process for Preparation of Rubber Silica Masterbatches based on the use of Polymer Latices FIELD OF INVENTION
The present invention relates to a filled polymer masterbatch based on polymers derived from latices, and to a process for preparing it.
In one of its embodiments, the present invention relates to the hydrophobicizing of particles, particularly mineral particles that are hydrophilic and have surface hydroxyl groups, for example, silica, silicates, clay, alumina, titanium dioxide and the like. The invention also extends, however, to treatment of non-mineral particles, for instance carbon black. In another of its embodiments, the present invention also relates to a filled, particularly silica-filled, polymer latex. In yet another embodiment, the invention relates to a silica-rubber masterbatch, and to a process for preparing it.
BACKGROUND OF THE INVENTION
In recent years, there has developed a considerable interest in silica reinforced tires, particularly since the appearance in 1992 of the Groupe Michelin (G-M) patents (EP
OS 01 227 A l; AU-A-111 77 192) which disclose that tires made with tread formulations incorporating precipitated silica enjoy some important performance advantages over those based on conventional carbon black filler. Improvements are claimed for this "Green Tire" in the areas of (a) lower rolling resistance, (b) better traction on snow, and (c) lower noise generation, when compared with conventional tires filled with carbon black.
Rubber for tires is often supplied by a rubber producer to a tire manufacturer in the form of a masterbatch to allow for fast processing into rubber compounds.
These masterbatches may contain two or more of: an elastomer, which is typically a hydrocarbon rubber, an oil extender and/or a filler. Examples of commercial masterbatches include Taktene~ 1359, a solution polybutadiene/carbon black/oil masterbatch available from Bayer and various Carbomix~ emulsion styrene-butadiene copolymer/carbon black masterbatch grades available from DSM-Coplymer, U.S.A.
The conventional filler for these commercial masterbatches has been and remains carbon black in the form of fine particles. These particles are naturally hydrophobic and therefore disperse relatively easily within the hydrophobic elastomer. In contrast, precipitated silica has a relatively hydrophilic surface, and considerable difficulty has been encountered in dispersing this filler into the hydrophobic rubber elastomer.
In the past, efforts have been made to make masterbatches from elastomer dis-persions and aqueous dispersions of silica, such as those referred to and attempted by Burke, in United States patent 3,700,690. Burke attempted to overcome the previously known difficulties of incorporating fine particles of silica uniformly into a masterbatch. At the time of Burke, there were no elastomer-silica masterbatches offered in the commercial market, and no commercial products using the Burke technology have appeared since.
EP 0 849 320 discloses silica masterbatches based on emulsion polymers.
However, the properties of the resulting masterbatches are not disclosed and the general formula of the applied coupling agents disclosed include a large number of different chemical entities which exhibit a broad range of effectiveness in the described process. Neither the coupling agents utilized in this present invention nor their beneficial effects are made available to the public by this document.
WO 98/53004 discloses silica masterbatches based on various polymers including rubbers. The process for masterbatch preparation which is described in WO

is based on the use of polymer solutions.

SUMMARY OF THE INVENTION
It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.
It is yet another object of the present invention to provide a novel masterbatch composition comprising a relatively hydrophobic particulate material and a polymer derived from a latex.
It is yet another object of the present invention to provide a novel process for pro-ducing a masterbatch composition comprising latex-derived polymer and a relatively hydrophobic particulate material.
Another object of the invention is to provide uses of the rubber mixes the present invention in the manufacture of molded or extruded parts.
DETAILED DESCRIPTION OF THE INVENTION
These objects are realized by a process for producing a composition comprising the steps of:
(1) contacting particles with a compound of Formula I:
R ~ R~
6~N-R4-Sip R2 R R
or an acid addition or quaternary ammonium salt thereof, in which:
at least one of R', RZ and R3 are hydroxyl or hydrolyzable groups;
R; is a divalent group that is resistant to hydrolysis at the Si-R4 bond;

RS is selected from hydrogen; a C,~o alkyl; a C,_~o mono-, di- or tri-unsatu-rated alkenyl group; a C6-C4o aryl group; a group of the formula:

Cx H2xN~R14 in which ~ is an integer from 2 to 10, R'3 and R", which may be the same or different, are each hydrogen; C,_,g alkyl; C,_,8 mono-, di- or tri-unsaturated alkenyl; phenyl;
a group of formula:
-(CH2)b /
CH=CH2 wherein b is an integer from 1 to 10;
a group of formula:

-(CH2)~ N ~R22 wherein c is an integer from 1 to 10 and R" and R'3 which may be the same or different. are each hydrogen, C,_,o alkyl group or CZ_,o alkenyl group, provided that there is no double bond in the position alpha to the nitrogen atom;
a group of formula:
-~ (CH2~~NH ~d~H
wherein r is an integer from 1 to 6 and d is an integer from 1 to 4;

R6 may be any of the groups defined for R5, or RS and R6 may together form a divalent group of formula:
/(CH2)t~
A\(CH )/
2v in which A is selected from the group comprising -CHR or -NR group in which R is hydrogen or a C,~o alkyl or CZ_ao alkenyl group, a Cb-C4o aryl group, an oxygen atom and a sulfur atom, and t and v are each independently 1, 2, 3 or 4; provided that the sum of t and v does not exceed 6, and (2) contacting the particles with a compound of the Formula II:

R12_SI\R16 (II) in which:
I 5 R'', R'6 and R" have the same definitions as R', R' and R~ : and R''' is selected from a Cg_~o alkyl group or a C8_4o mono-, di- or tri-unsaturated alkenyl group, either of which can be substituted by one or more aryl groups, preferably phenyl groups; a group of formula:

N _R18-R20~
or an acid addition or quaternary ammonium salt thereof in which R'g is a divalent group resistant to hydrolysis at the Si-R'8 bond, R'9 is selected from a C,_4o alkyl group, a CZ~o mono-, di- or tri-unsaturated alkenyl group, a substituted aromatic group, for example the phenylene group -(C6H4)-, the biphenylene group -(C6H~)-(C6H~)-, the -(C6H4)-O-(C6H~)- group or the naph-thylene group, -(C,oHb)-, the aromatic group being unsubstitued or substituted by a C,_2° alkyl or CZ_,° mono-, di- or tri-unsaturated alkenyl group; and Rzo may be any of the groups defined for R'9, with the provisos that R'9 and RZ°
do not have a tertiary carbon atom adjacent to the nitrogen atom and that at least one of R'9 and R'° has a carbon chain at least 8 carbon atoms in length uninterrupted by any heteroatoms and (3) admixing the particles of step (1) and (2) with one or more polymers in the latex state.
In compound (I) preferably two of R', R' and R; and most preferably R', R' and are hydroxyl or hydrolyzable groups.
It is furthermore preferred that all three of the groups R', R' and R3 are readily hydrolyzable. Suitable groups R' include hydroxyl groups and hydrolyzable groups of formula OCPHZP+1, where p has a value from 1 to 10. The alkyl chain can be interrupted by oxygen atoms, to give groups, for example, of formula CH30CH,0-, CH30CH,OCHZO-, CH3(OCH,)a0-, CH30CH,CH20-, C,H;OCH,O-, C,H;OCH,OCHZO-, or CZH;OCH,CHZO-. Other suitable hydrolyzable groups in-chide phenoxy, acetoxy, chloro, bromo, iodo, ONa, OLi, OK or amino or mono- or dialkylamino, wherein the alkyl groups) have 1 to 30 carbon atoms.
R' and R' can take the same values as R', provided that only one of R', R' and R3 is chloro, bromo or iodo. Preferably, only one or two of R', R' and R3 is hydroxyl or ONa, OLi or OK.
Non-limiting examples of groups R' and R3 that are not hydrolyzable include C,_,o alkyl, C,_,o mono- or diunsaturated alkenyl, and phenyl.

R' and R3 can also each be a group -R4-NRSR6, discussed further below. It is further-more preferred that R', R' and R3 are all the same may be CH30-, C,H50- or C3H80-.
Most preferably they are all CH30-.
The divalent group R4 is preferably such that N-R~-Si is of the formula:
N-(CH,)P(O)o(C6H~)n(CH,)m(CH=CH)~-Si in which k, m, n, o and p are all whole numbers. The order of the moieties between N and Si is not particularly restricted other than neither N nor O should be directly bound to Si. The value of k is 0 or 1, the value of m is from 0 to 20 inclusive, the value of n is 0, 1 or 2, the value of o is 0 or 1 and the value of p is from 0 to 20 in-clusive, with the provisos that the sum of the values of k, m, n, o and p is at least 1 and not more than 20 and that if o is l, p is 1 or greater and the sum of k, m and n is 1 or greater, i.e. that the Si atom is linked directly to a carbon atom. There should be no hydrolyzable bond between the silicon and nitrogen atoms. Preferably, m is 3 and 1, n, o and p are all 0, i.e., R° is -CH,CH,CHz-.
The group R' is preferably a C$_,o monounsaturated alkenyl group. most preferably a C,6_,8 monounsaturated alkenyl group. R6 is preferably hydrogen.
Suitable compounds of Formula I include, but are not limited to: 3-amino-propylmethyldiethoxysilane, N-2-(vinylbenzylamino)-ethyl-3-aminopropyl-trimeth-oxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, trimethoxysilylpropyl-diethylenetriamine, N-2-(aminoethyl)-3-aminopropyltris(2-ethylhexoxy)silane, 3-aminopropyldiisopropylethoxysilane, N-(6-aminohexyl)aminopropyltrimethoxy-silane, 4-aminobutyltriethoxysilane, 4-aminobutyldimethylmethoxysilane, triethoxy-silylpropyl-diethylenetriamine, 3-aminopropyltris(methoxyethoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyl-tris(2-ethylhexoxy)silane, 3-aminopropyldiisopropylethoxysilane, N-(6-aminohex-_g_ yl)aminopropyltrimethoxysilane, 4-aminobutyltriethoxysilane, and (cyclohexyl-aminomethyl)-methyldiethoxysilane.
Preferred compounds of Formula I include those in which RS is hydrogen and R6 is the mixed alkyl group from the following: soya alkyl, tall oil alkyl, stearyl, tallow alkyl, dihydrogenated tallow alkyl, cocoalkyl, rosin alkyl, and palmityl, it being understood that in this case the alkyl groups may include unsaturation.
It is preferred that at least one of R~, R'3 and R'4 has a chain of at least 8 carbon atoms, more preferably at least 10 carbon atoms, uninterrupted by any heteroatom.
The compound of Formula I can be used as the free base, or in the form of its acid addition or quaternary ammonium salt, i.e.
X
R ~0+ R
6iN -R4-Sip R2 wherein R', R', R3, R;, R' and R6 are as defined above; R' is selected from hydrogen, a C,_ao alkyl group or C,_~o mono-, di- or tri-unsaturated alkenyl group, and X is an anion. X is suitably chlorine, bromine, or sulphate, of which chlorine and bromine are preferred, and R' is preferably hydrogen.
Non-limiting examples of suitable salts of compounds of Formula I include N-oleyl-N-[(3-triethoxysilyl)propyl] ammonium chloride, N-3-aminopropylmethyldiethoxy-silane hydrobromide, (aminoethylamino-methyl)phenyltrimethoxysilane hydro-chloride, N-[(3-trimethoxysilyl)propyl]-N-methyl, N-N-diallylammonium chloride, N-tetradecyl-N,N-dimethyl-N-[(3-trimethoxysilyl)propyl] ammonium bromide, 3 [2-N-benzylaminoethyl-aminopropyl]trimethoxysilane hydrochloride, N-octadecyl-N,N-dimethyl-N-[(3-tri-methoxysilyl)propyl] ammonium bromide, N-[(trimethoxy-silyl)propyl]-N-tri(n-butyl) ammonium chloride, N-octadecyl-N-[3-triethoxy-silyl)propyl] ammonium chloride and N-2-(vinylbenzylamino)ethyl-3-aminopropyl-trimethoxysilane hydrochloride.
The sum of t and v is preferably 4.
Preferably, R'8 is a C,-C4° saturated or unsaturated group (e.g., alkenyl, aryl, cycloalkyl and the like).
It is preferred to use the compound of Formula I in salt form. The most preferred compound is N-oleyl-N-[(3-trimethoxysilyl)propyl] ammonium chloride.
In the compound of Formula II, the possible and preferred values for R'', R'6 and R"
are the same as the possible and preferred values for R', R' and R' that are discussed above in relation to Formula I.
If R'' is an amino group of formula -R'8-NR'9Rz°, preferred values for R'8 are such that N-R'$-Si includes groups of the formula:
N-(CH,)P(O)o(C6H~)~(CH,)m(CH=CH)~-Si in which k is 0 or l, m is 0 to 20 inclusive, n is 0, 1 or 2, o is 0 or 1 and p is 0 to 20 inclusive, provided that the sum of k, m, n, o and p is at least 1 and not greater than 20, and further provided that if o is l, p is also 1 or greater, and the sum of k, m and n is 1 or greater.
The order of the moieties between N and Si is not particularly restricted other than neither N nor O should be directly bound to Si. There should be no hydrolyzable group between the silicon and nitrogen atoms. Preferably k, n, o and p are all 0 and m is 3, i.e. R'8 is -CHZCH,CHZ-.

R'' may be a moiety containing at least one primary, secondary, or tertiary amine nitrogen. In this case the amino group bonded to R'$- is given by the formula -NR'~R'°. R'9 may be an H or a C,_~° alkyl group or a Cz_4° mono-, di- or tri-unsaturated alkenyl group. R'~ may, also be a C,_,° alkyl-substituted or CZ_,° alkenyl-substituted aromatic group. The aromatic group may be, for example, the phenylene group -(C6H4)-, the biphenylene group -(C6H~)-(C6H4)-, the -(C6H~)-O-(C6Ha)-group, or the naphthylene group -(C,°H6)-. R'° may be one of the same groups as R'~ with the further proviso that at least one of R'9 and R'-° must contain a continuous carbon chain of at least 8 carbons in length, uninterrupted by any heteroatoms.
As stated above, if R'9 and R'° are other than hydrogen, the carbon atom attached to the nitrogen atom is not tertiary. Preferably the carbon atom attached to the nitrogen atom is primary, i.e., -CH,-.
It is preferred that R'9 is a mono-unsaturated alkenyl group of 12-20 carbons in length and most preferable that R'9 is a mono-unsaturated alkenyl group of 16 to 18 carbons in length. It is most preferable also that R'° is H.
Alternatively, R'' may be a moiety which contains a mineral acid salt or a quaternary ammonium salt of an amine. The formula of R''- may thus be described by the exten-ded formula -R'8-NR'9R'°~RZ'X wherein -R's-, R'9 and R'° are as previously defined and R'' may be a H, or a C,_~° alkyl or C,_~° mono-, di- or tri-unsaturated alkenyl group and X is an anion, preferably Cl' or Bi , although HS04~ or S04- are also permissible.
There is the further proviso that at least one of R'9 and R'-° must contain a continuous carbon chain of at least 8 carbons in length, uninterrupted by any heteroatom.
It is preferred to use an amine salt where R'9 is a mono- or di-unsaturated alkenyl group of 12-20 carbons in length and most preferably that R'9 is a mono- or di-unsaturated alkenyl group of 16 to 18 carbons in length. It is most preferable also that R'° is H
and that R'' is H and X is chlorine.

The preferred hydrophobicizing agent of Formula II is N-oleyl-N-(3-trimethoxy-silyl)propyl ammonium chloride.
Steps (a) and (b) may be conducted concurrently or sequentially. If Steps (a) and (b) are conducted sequentially, it is preferred to conduct Step (a) followed by Step (b).
As will be apparent to those of skill in the art, there are instances where Formulae I
and II may be the same compound - e.g., when RS=R'9= a CB~o alkyl group or RS=R'9= a Cg_4o mono-, di- or tri-unsaturated alkenyl group. Thus, in such cases where Formulae I and II are the same compound, it will be clearly understood that the present process intentionally embodies a single step process (i.e., where the compound of Formulae I and II is added in a single step) and a mufti-step process (i.e., where the compound of Formulae I and II is added proportionally in two or more steps).
Preferably, the steps (1) and/or (2) are carried out in an aqueous solution, dispersion or slurry, so that the product of the process is an aqueous dispersion or slurry of hydrophobicized mineral particles.
In one preferred embodiment, the dispersion or slurry resulting from the present pro-cess, and containing the treated particles (preferably mineral particles such as silica), is then mixed with a polymer latex to form a preblend which is then coagulated and dried to form a silica-filled polymer masterbatch. Owing to the hydrophobicized nature of the silica filler, it is well dispersed in the polymer. This preferred embodi-ment results in the in situ production of a masterbatch composition comprising the polymer and the treated particles. By "in situ production" it is meant, that treated particles are incorporated into a masterbatch composition without being at first isolated (i.e., separated from the dispersion or slurry, and subsequently dried).

In another embodiment, the preblend containing the polymer latex and treated particles and optional additives is not coagulated but is used directly for the production of paints, dipped goods or coated fabrics.
In another of its aspects, the present invention provides a polymer masterbatch comprising treated particles having bound thereto an aminohydrocarbonsilane moiety - i.e., a hydrocarbon moeity comprising both silicon and nitrogen.
Preferably, the aminohydrocarbonsilane has the formula Ra R~2 SI Rb W Rc in which:
1 S R~, Rb and R' are the same or different and each is selected from -O- and -CPH2P-, optionally substituted by one or more oxygen atoms and wherein p is an integer of from 1 to 10; and R'' is a C8_~o alkyl group; a Cg~,o mono-, di- or tri-unsaturated alkenyl group; a group of formula \N _R4-6~
R
or an acid addition or quaternary ammonium salt thereof in which R~ is a divalent group resistant to hydrolysis at the Si-R' bond, RS is hydrogen C,~o-alkyl, C,~o mono-, di- or tri-unsaturated alkenyl; a group of formula -ArCWH2W+, in which Ar represents a divalent aromatic group and w is an integer from 1 to 20, and R6 may be any of the groups defined for R5, with the proviso that at least one of RS and Rb must have an uninterrupted carbon chain at least 8 carbon atoms in length.
In yet another of its aspects, the present invention provides a polymer/filler masterbatch comprising treated filler particles having a contact angle with water of at least about 100°. Preferably, the treated particles have a contact angle of at least about 110°, more preferably in the range of from about 115° to about 160°, even more preferably in the range of from about 120° to about 150°, most preferably in the range of from about 120° to about 140° with water .
The contact angle of the particles with water may be readily determined according to the following procedure:
(i) double-sided tape is attached to a probe (e.g., a stirrup) and coated with the particulate material by immersing the tape in a sample of the particulate material;
(ii) excess powder is removed by gentle tapping and large powder clusters are removed by careful wiping;
(iii) the probe coated with particulate material is immersed into distilled water using a conventional contact angle analyzer (e.g., a Cahn Dynamic Contact Angle Analyzer) at a rate of 100 microns per second.
This procedure results in determination of the advancing contact angle of the particles.
The particles used in step (1) and (2) are preferably hydrophobic and may be a mineral material selected from the group comprising silicates, silicas (particularly silica made by carbon dioxide precipitation of sodium silicate), clay, titanium dioxide, alumina, calcium carbonate, zinc oxide and mixtures thereof. The particle may also be a particulate non-mineral material such as carbon black. Of course, mix-tures of particulate materials may be used.
In a preferred embodiment, the step ( 1 ) and/or (2) are carried out in an aqueous dis-persion or slurry and the concentration of the aqueous dispersion or slurp' of silica particles may be in the range from 1 to 30 percent by weight of silica in water, pre-ferably in the range from 5 to 25 percent by weight of silica in water.
Dried amorphous silica suitable for use in accordance with the invention may have a mean agglomerate particle size in the range from 1 to 100 microns, preferably in the range from 10 to 50 microns and most preferably 10 to 2~ microns. It is preferred that less than 10 percent by volume of the agglomerate particles are below ~
microns or over 50 microns in size.
A suitable amorphous dried silica moreover has a BET surface area, measured in accordance with DIN (Deutsche Industrie Norm) 66131, of in the range from 50 to 450 square meters per gram and a DBP absorption, as measured in accordance with DIN 53601, of in the range from 150 to 400 grams per 100 grams of silica. and a dry-ing loss, as measured according to DIN ISO 787/II, of in the range from 0 to 10 per-cent by weight.
If filter cake is used, it may be made by any known means such as described in Ullmann's Encyclopedia of Industrial Chemical Vol A23 pages 642-643, VCH
2~ Publishers, ~1993. The filter cake has a preferred solids content of in the range from 5 to 30 percent by weight, most preferably 15 to 25 percent by weight, and it may be redispersed in water in accordance with the present process to give a silica concentration of in the range from 5 to 20 percent by weight and most preferably 8 to 12 percent by weight. It is preferred to use a filter cake.

If a never-filtered slurry prepared from the known reaction of a solution of alkali metal silicate with either mineral acid or carbon dioxide is used, it is preferred that the solids content of the never-filtered slurry be in the range from 1 to 30, more preferably S to 10 percent by weight of silica.
In the case of the use of a never-filtered slurry, the prior addition of additional emulsifier or stabilizer to the latex is helpful to prevent an early coagulation in the masterbatch process. Suitable materials include nonionic emulsifiers and phosphates i.e., trisodium phosphate.
The slurry temperature may be in the range from 0 to 100 degrees Celsius if the process is conducted at atmospheric pressure or in the range from 0 to 135 degrees Celsius if the operation is conducted in a pressure vessel. Most preferably, the process is conducted at atmospheric pressure, in which case, the preferred temperature is in the range from 30 and 95 degrees Celsius and most preferably in the range from 45 to 90 degrees Celsius.
It is desirable that, prior to the addition of the silica particles to the compound of Formula I, the dispersion or slurry shall have a pH in the range from 6 to 8, more pre-ferably from 6.8 to 7.2. If necessary, the pH can be adjusted by addition of acid or alkali, for example mineral acid, alkali metal hydroxide, alkaline earth hydroxide, ammonium hydroxide and the like. These can be added as such or in aqueous solution.
The amount of the compound of Formula I may be in the range from 0.1 to 20 per-cent by weight of the mineral particles in the slurry (dry basis) and preferably 0.25 to 10 percent by weight and most preferably 0.5 to 2 percent by weight.
Preferably, the amount of the compound of Formula I used varies inversely with the mineral particle size. The compound may be added to the slurry in its natural state, either as a liquid or a solid. However, to facilitate dispersion, it is preferred where possible to add the compound as a liquid. If the melting point of the compound is below 95 degrees Celsius, it is preferred to add it to the slurry in a molten state at a temperature at least 5 degrees Celsius above the melting point, provided the temperature of the compound in the liquified state does not exceed 100 degrees Celsius and provided that the compound does not decompose under these conditions.
If the melting point exceeds 95 degrees Celsius, it is most preferred to use a solvent.
Preferred solvents are water and alcohols containing 1 to ~ carbon atoms and most preferably those containing 1 to 3 carbon atoms, that is to say methanol, ethanol, n-propanol or isopropanol. If the compound of Formula I is an alkoxysilane, then most preferably, the alkoxy group of the solvent alcohol will be the same as the alkoxy group of the alkoxysilane. For example, if the compound of Formula I is a methoxysilane, the preferred solvent is methanol. The concentration of the compound in the solvent may be from 10 to 90 percent by weight and more prefer-ably between 25 and 7~ percent by weight and most preferably, 50 percent by weight. Preferably, the solution can be prepared and added to the slurry at a temperature between a lower limit of 0 degrees Celsius and an upper limit which is the lower of at least 10 degrees below the boiling point of the solvent and 9~
degrees Celsius. The dispersion of the compound is effected by mixing.
It is preferred that, for the specific compound of Formula I which is added, the equivalent balance (EB) should be calculated. The EB is used to determine whether mineral acid or alkali metal hydroxide. or solution thereof, should be added.
The equivalent balance (EB) may be determined from the absolute value of the sum of the group values of X (if present), R', R- and R~ and the magnitude of the sum of the group contributions of X (if present), R', R' and R3 together with the weight added and the molecular weight of the compound of Formula I, according to the following scheme: The group contribution of X for either X=Cl or X=Br is -1, thus, if X
is pre-sent, it is given a value of -1. The group contribution of each of R', R' and R' is gen-erally zero for all groups except as follows: if the group is CH3C00, Cl or Br, in which case it is -1, or if it is amine (including an imine), ONa, OK or OLi in which case it is +1. If the sum of the group contributions for X, R', R' and R' is zero, no adjustment with mineral acid or alkali metal hydroxide (or solutions thereof) is nec-essary. If the sum of the group values is a positive integer, adjustment with mineral acid is desirable, and if it is negative, adjustment with alkali metal hydroxide is de-sirable.
For example, where R~=OCH3, R'-=CHI, R3=Cl and X=Br, the sum of the group val-ues (g.v.) is:
E = (g.v. OCH3)+(g.v. CH3)+(g.v. Cl)+(g.v. Br) _ (0)+(0)+(-1)+(-1) _ -2 The negative sign in front of the sum indicates adjustment with alkali metal hydrox-ide is required. The number of equivalents of alkali required is given by the equiva-lent balance (EB) which includes the absolute value of the sum of the group contri-butions (Eabs.) as a scaling factor:
EB = Eabs x weight in grams of the chemical added molecular weight of the added chemical In continuing the example, if a process according to the present invention were scaled so as to require 6,000 grams of a chemical of Formula I with a molecular weight of 350 grams and the sum of the group values gave -2, EB would be calcu-lated as follows:
EB = -2 x 6000/350 = -34.28 gram-equivalents Thus, in this example, 34.28 gram-equivalents of alkali metal hydroxide would be added. Sodium hydroxide is the preferred alkali metal hydroxide. The weight of sodium hydroxide would be:
Weight = (EB) x (Equivalent Weight of NaOH) = 34.28 x 40.0 = 1371.2 grams The preferred technique according to the invention is to dissolve the alkali metal hy-droxide or mineral acid in water so as to obtain a concentration in the range from 1 to 25% by weight and most preferably, 5 to 10% by weight prior to adding the solution to the slurry.
Preferably, the amount of the hydrophobic compound of Formula II to add is gener-ally in the range from 0.5 to 20 percent by weight of the weight of the particles (pref erably mineral particles such as silica) in the slurry (dry basis), and is inversely pro-portional to the particle size of the silica particles The compound may be added to the slurry in its natural state, either as a liquid or a solid. However, to facilitate dispersion, it is preferred, where possible, to add the compound as a liquid. If the melting point of the compound is below 9~ degrees Celsius, it is preferred to add it to the slurry in a molten state at a temperature at least 1 S 5 degrees Celsius above the melting point, provided the temperature of the com-pound in the liquified state does not exceed 100 degrees Celsius and provided that the compound does not decompose under these conditions. If the melting point ex-ceeds 95 degrees Celsius, it is most preferred to use a solvent. Suitable solvents are alcohols containing 1 to 5 carbon atoms and most preferably those containing 1 to 3 carbon atoms, that is to say methanol, ethanol, n-propanol or isopropanol. If the compound of Formula II is an alkoxysilane, most preferably, the alkoxy group of the solvent alcohol will be the same as the alkoxy group of the alkoxysilane. For ex-ample, if the compound of Formula II is a methoxysilane, the preferred solvent is methanol. The concentration of the compound in the solvent may be in the range from 10 to 90 percent by weight and most preferably in the range from 25 to 7~
per-cent by weight and most preferably, 50 percent by weight. Preferably, the solution is prepared and added to the slurry at a temperature between a lower limit of 0 degrees Celsius and an upper limit which is the lower of at least 10 degrees below the boiling point of the solvent and 95 degrees Celsius.

After the addition of the hydrophobic compound of Formula II which is added, the equivalent balance (EB) should be calculated to determine how much, if any, mineral acid or alkali metal hydroxide (or solutions thereof) to add. The equivalent balance (EB) may be determined from the absolute value of the sum of the group values of X, R'', R'6 and R" and the weight added, and the molecular weight of the compound, according to the following scheme: The group contribution of X for either X=C1 or X=Br is -l, thus if X is present it is given a value of -1. The group contribution of each of R'', R'6 and R" is generally zero for all groups except as follows: if the group is CH3C00-, Cl- or Br-, in which case it is -1, or if it is amino, ONa, OK, or OLi in which case it is +l. If the sum of the group contributions for X, R'', R'6 and R" is zero, no adjustment with mineral acid or alkali metal hydroxide (or solutions thereof) is necessary. If the sum of the group values is a positive integer, adjustment with mineral acid is desirable, and if it is negative, adjustment with alkali hydroxide is desirable.
For example, where R'S=OC,H;, R'6=OCH~ R"=CH3 and X=C1, the sum E of the group values (g.v.) is:
E = (g.v. OC~H;)+(g.v. OCH~)+(g.v. CH;)+(g.v. C1) =(0)+(0)+(0)+(-1) _ -1.
The negative sign in front of the sum indicates adjustment with alkali metal hydrox-ide is required. The number of equivalents of alkali required is given by the equiva-lent balance (EB) which includes the absolute value of the sum of the group contri-butions (Eabs) as a scaling factor.
EB = Eabs x weight in grams of the compound added molecular weight of the added chemical.
In continuing the example, if a process according to the present invention were scaled so as to require 3450 grams of a compound of Formula II with a molecular weight of 466 grams and the sum of the group values gave -1, EB would be calcu-lated as follows:
EB = ~ -1 ~ x 3450/466 = 7.4. gram-equivalents.
Thus, in this example, 7.4 gram-equivalents of alkali metal hydroxide would be added. Sodium hydroxide is the preferred alkali metal hydroxide. The weight of sodium hydroxide added would be:
Weight = (EB)x(Equivalent Weight of NaOH) = 7.4 x 40.0 = 296 grams.
The preferred technique according to the invention is to dissolve the alkali hydroxide or mineral acid in water so as to obtain a concentration in the range from 2 and 25%
by weight and most preferably in the range from 2 to 10% by weight prior to adding the solution to the slurry.
It is known to incorporate a coupling agent into rubber that is intended to be vulcan-ized and used, for instance, in tires. Suitable coupling agents include those described in United States patent 4,704,414, published European patent application 0,670,347A1 and published German patent application 4435311A1. Suitable coupling agents are mixtures of bis[3-(triethoxysilyl)propyl]monosulfane, bis[3-(tri-ethoxysilyl)propyl]disulfane, bis[3-(triethoxysilyl)propyl]trisulfane and bis[3-(triethoxysilyl)propyl]tetrasulfane, available under the trade names Si69~
(Degussa AG) or Silquest~ A-1289 (average sulfane 3.5) and Silquest~ A-1589 (CK-Witco, average sulfane 2.0). Another suitable coupling agent is a proprietary silane available from CK-Witco under the trade name Silquest~ RC-2.
In the past, achieving a good balance between the coupling agent and particles, such as silica, without scorching or premature curing has proven difficult. In accordance with the invention, if particles, particularly silica particles, are being treated to render them hydrophobic for use in rubber which is subsequently to be vulcanized, it is possible to include a step of adding a coupling agent in the process of the invention, so that the coupling agent becomes attached to the surface of the hydrophobicized mineral particles and becomes dispersed in the rubber with the mineral particles.
Thus, in some preferred embodiments of the invention, a coupling agent is added to the dispersion, more preferably after the addition of the compound of Formula I but before the compound of Formula II is added. As discussed above, in some cases, Formulae I and II may represent the same compound. In these cases, it is preferred to add the coupling agent between sequential additions of the compound of Formulae I
and II.
The coupling agent may be added after any addition of mineral acid or alkali metal hydroxide that is indicated by the calculation of the EB. Suitable and preferred coupling agents are those disclosed in WO-A-98/53004.
In this invention, the hydrophobicized silica, in the aqueous dispersion or slurry, is incorporated into a polymer latex, for example, an elastomer latex to form a silica rubber masterbatch. It is particularly preferred that the hydrophobicized silica shall have been treated with a coupling agent, for example Si-69~, or Silquest~ RC-2, as discussed above before it is incorporated into the latex.
Non-limiting examples of suitable latices include those resulting directly from the emulsion polymerization of butadiene, styrene, isoprene, acrylonitrile, vinyl chloride, acrylic acid, methacrylic acid, acrylic esters or mixtures thereof. Especially suitable are emulsion latices of butadiene co-styrene and butadiene co-acrylonitrile.
Other suitable lances are those prepared artificially from polymer solutions or dry polymers by processes such as those disclosed in United States Patent 4,177,177, page 1, the contents of which are herein incorporated by reference. Preferred artificial latices are those prepared by first dissolving the polymer in a suitable solvent to form a cement, emulsifying the cement so-formed with an appropriate amount of water and an emulsifier, stripping off the solvent and if desired, concentrating the finished latex.

Suitable artificial latices so-preparable include, but are not limited to those of butyl rubber, polychloroprene rubber, solution styrene-butadiene copolymers, solution polybutadiene and the like. Also suitable for the process are natural latices, such as those produced by hevea brasiliensis and members of the Parthenium species, commonly referred to as natural rubber latex and guayule, respectively.
Modified natural lances such as those resulting from epoxidizing natural rubber latex are also suitable.
Most preferred are lances of butadiene-styrene copolymers, butadiene-acrylonitrile copolymers and butadiene-acrylonitrile-styrene terpolymers. It is even more preferred that these are produced via emulsion polymerization. The latices may be used directly from the polymerization process but it is preferred that they are stripped of residual monomer and concentrated prior to use.
The polybutadiene, butadiene styrene copolymers, isoprene styrene copolymers, butadiene isoprene styrene terpolymers, butadiene acrylonitrile copolymers, buta-diene acrylonitrile styrene terpolymers, can optionally comprise further polymeri-zable monomers with functional groups, e.~. amine, amide, carboxyl, ester, sulfonic acid or hydroxyl.
Optionally, processing oil and antioxidants may be added to the polymer latex prior to mixing with the treated silica slurry, or they may be added after mixing the treated silica slurry and the latex.
The amount of latex that is added is such that the final masterbatch may contain in the range from 5 to 2~0 parts of silica per hundred parts of polymer, preferably from to 100 parts of silica per hundred parts of polymer, most preferably from 60 to 80 parts of silica per hundred parts of polymer.
The latex and, optionally, oil and antioxidants, is mixed with the treated silica slurry 30 to form a preblend.

The preblend is most suitable for making masterbatches by coagulating and then drying, or simply by drying alone.
If coagulation is used to prepare the masterbatch, standard emulsion rubber latex co-S agulants or latex destabilizers such as solutions of mineral salts, solutions of mineral acids in water either alone or in combination with flocculation aids may be used to destabilize the preblend and so obtain the masterbatch in the form of a wet crumb.
The coagulation can be can be carried out either as a batch process or as a continuous process. These and other techniques are well known to those skilled in the art of latex coagulation. Alternatively, the preblend may be coagulated by means of high shear, such as by passing it through a small orifice at high flow rates. In all of the above cases, the wet masterbatch crumb, (i.e., the coagulum of the preblend) is then separated from the coagulation liquid "serum" by screening or other solid-liquid separation process. The coagulated wet masterbatch crumb may be further treated by washing, and/or dewatered by pressing. It is finally dried by conventional means such as hot air oven, microwave or fluidized bed drier to yield the dry masterbatch.
The masterbatch also may be prepared without the coagulation step simply by drying the preblend, for example by hot-air spray drying, by means of a wiped-film evapo rator or drying extruder or the like.
It is preferred to prepare the dry masterbatch by coagulating the preblend with solu tions of mineral acids and/or solutions of mineral salts in water either alone or in combination with flocculation aids, separating the crumb by screening, washing the 2~ crumb with water and then drying the wet crumb by a hot air dryer.
However, another object of the invention is the filled latex in the wet state.
i.e., the preblend itself. The preblend can be used as such, or with additional stabilizers, for the production of : paints, dipped goods such as rubber gloves, dental dams, balloons and specialty innertubes, or for coating fabrics, carpet backings and paper.
The filled latex is also a suitable base for architectural caulks, either alone or in combination with ancillary ingredients.
Molded or extruded parts in the sense of the invention include cable sheating, hose, drive belts, conveyor belting, roll covers, shoe soles, gaskets, damping elements and tires, particularly tire treads.
To manufacture said molded or extruded parts from the inventive rubber masterbatches, other rubbers and rubber additives may be added, along with one or more of reaction accelerators, antioxidants, heat stabilizers, light stabilizers, anti-ozonants, processing aids, plasticizers, tackifiers, blowing agents, dyestuffs, pigments, waxes, extenders, organic acids, retarders, metal oxides and activators such as triethanolamine, polyethylene glycol, hexanetriol, trimethylolpropane or sulphur-containing silyl ethers which are known within the rubber industry. Other fillers may also be added to the rubber mixes. Besides hydrophobized and non-hydrophobized oxide and silicate fillers, rubber gels and/or carbon blacks may also be used.
The carbon blacks which may be used for this purpose are well known in the nibber industry and may be manufactured using the lamp black, furnace black or channel black processes and have BET areas of 20 to 200 m'/g. Examples include SAF, ISAF, HAF, FEF and GPF carbon blacks.
The rubber additives are used in quantities well-known to those of skill in the art, which are based partly on the intended application. These quantities may be between 0.1 and SO % by wt. in relation to the total quantity of rubber.
Sulphur, sulphur donors or peroxides may be used as crosslinking agents in the manufacture of said moulded or extruded parts. The rubber mixes referred above also preferably contain vulcanization accelerators. Examples of such accelerators include mercaptobenzothiazoles, guanidines, thiurams, dithiocarbamates, thioureas and thiocarbonates. The vulcanisation accelerators, along with sulphur or peroxide, are used in quantities of 0.1 to 10 % by wt. (optimum: 0.1 to 5 % by wt.) in relation to the total quantity of rubber.
The above mentioned materials , may be conveniently incorporated into the masterbatch by simple mixing, i.e., in a Banbury or other type of internal mixer, a mixing extruder, or on an open mill. Single or multiple mixing steps may be employed.
The mixed compound may then be placed in a mold or otherwise formed to the desired shape. Vulcanization can be carried out at temperatures of 100-200 °C
(optimum: 130 to 180 °C), if necessary, under pressures of 10-200 bar.
Embodiments of the present invention will be described with reference to the fol-lowing Examples which should not be used to limit the scope of the invention.
EXAMPLES
For the preparation of the examples according to the invention, the precipitated silica grade HiSil~ 233 (PPG Industries, USA), the sulphur silane Si69~ (Degussa AG, Germany) and N-Oleyl-N-(trimethoxysilyl)propyl ammonium chloride according WO 98/53004 were used.
Example 1 Krynol~ 1712 (ESBR, Bayer AG) was used as the latex component. The latex was extended with 37.5 phr aromatic oil and stabilised with 0.5 phr Vulkanox~
4020.
The rubber/silica masterbatch in example 1 was based on the following recipe:
100.0 phr ESBR (76.5 % butadiene, 23.5 % styrene) 37.5 phr aromatic oil 80.0 phr silica 6.4 phr Si69 4.0 phr N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride 1 ) Producing the hydrophobized silica suspension:
In order to obtain a 20 % silica suspension, 367.82 g silica were mixed with 1,471.28 g fully demineralised water. The silica suspension was heated to 50 °C
while being stirred. 1.79 N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state were added, followed by 13.79 g of a 2 % NaOH solution. 29.38 g Si69 were then added over a period of 30 minutes. After the addition of Si69, the mixture was stirred for 30 minutes. The treated silica suspension was then heated to 80 °C, and 16.60 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state were added over a period of 5 minutes. 12.87 g of a 10 % NaOH solution were then added over a period of 5 minutes. The mixture was stirred during all these process steps.
Lastly, fully demineralised water was added to dilute the hydrophobized silica suspension to 10 %.
2) Producing the preblend of oil-extended latex and hydrophobized silica:
431.03 g of a 40 % oil emulsion in water were added to 4,597.7 g of 10 % ESBR
latex and stirred thoroughly. This oil-extended latex contained:
459.77 g ESBR and 172.41 g aromatic oil.
The oil-extended latex and the hydrophobized silica suspension were mixed for minutes to form the preblend.
3) Coagulating the preblend of oil-extended latex and hydrophobized silica:
Coagulation was carried out at room temperature by adding 10 % sulphuric acid to the stirred mixture of oil-extended latex and hydrophobized silica until the pH was 4.8. The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 ~m filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter ,paper circle to remove the small amount of suspended silica. The resulting serum was clear. The filter was then dried.
The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.40 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.60 % of the silica dosage. The resulting wet masterbatch was dried at 70°C in a vacuum oven.
Example 2 Krylene~ 1500 (ESBR, Bayer AG) was used as the latex component. The latex was extended with 20 phr aromatic oil and stabilised with 0.5 phr Vulkanox 4020.
The rubber/silica masterbatch was based on the following recipe:
1 S 100.0 phr ESBR (76.5 % butadiene, 23.5 % styrene) 20.0 phr aromatic oil 80.0 phr silica 6.4 phr Si69 4.0 phr N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride 1) Producing the hydrophobized silica suspension:
In order to obtain a 20 % silica suspension, 400 g silica were mixed with 1,600 g fully demineralised water. The silica suspension was heated to 50 °C
while being stirred. 1.95 N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state were added, followed by 1 S.0 g of a 2 % NaOH solution. 31.9 g Si69 were then added over a period of 30 minutes. After the addition of Si69, the mixture was stirred for 30 minutes. The treated silica suspension was next heated to 80 °C, and 18.05 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state were added over a period of 5 minutes. 14.0 g of a 10 % NaOH solution were then added over a period of 5 minutes. The mixture was stirred during all these process steps.
Lastly, fully demineralised water was added to dilute the hydrophobized silica suspension to %.
2) Producing the preblend of oil-extended latex and hydrophobized silica:
250 g of a 40 % oil emulsion in water were added to 5,000 g of 10 % ESBR latex and 10 stirred thoroughly. This oil-extended latex contained:
500 g ESBR and 100 g aromatic oil.
The oil-extended latex and the hydrophobized silica suspension were mixed for minutes to form the preblend.
3) Coagulating the preblend of oil-extended latex and hydrophobized silica:
Coagulation was carried out at room temperature by adding 10 % sulphuric acid to the stirred preblend until the pH reached 4.8. The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 ~m filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear.
The filter was then dried. The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.3~ % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.65 of the silica dosage. The resulting wet masterbatch was dried at 70°C
in a vacuum oven.
Example 3 Perbunan~ NT 289 (NBR, Bayer AG) was used as the latex component. The rubber/silica masterbatch was based on the following recipe:
100.0 phr NBR (72 % butadiene, 28 % acrylonitrile) 80.0 phr silica 6.4 phr Si69 4.0 phr N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride 1 ) Producing the hydrophobized silica suspension:
In order to obtain a 20 % silica suspension, 22.22 g silica were mixed with 88.88 g fully demineralised water. The silica suspension was heated to 50 °C
while being stirred. 0.11 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state was added, followed by 0.83 g of a 2 % NaOH solution. 1.78 g of Si69 were then added over a period of 30 minutes. After the addition of Si69, the mixture was stirred for an additional 30 minutes. The treated silica suspension was next heated to 80 °C, and 1.00 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state was added over a period of ~ minutes. 0.78 g of a 10 % NaOH solution was then added over a period of 5 minutes. The mixture was stirred during all these process steps. As a final step fully demineralised water was added to dilute the hydrophobized silica suspension to 10 %.
2) Producing the preblend of latex and hydrophobized silica:
277.78 g of 10 % NBR latex and the hydrophobized silica suspension were mixed by stirring for 10 minutes to give the preblend.

3) Coagulating the preblend of latex and hydrophobized silica:
500 g of fully demineralised water were placed in a glass vessel equipped with a stirrer. The pH was adjusted to 5 with 1 % sulphuric acid. The preblend of latex and hydrophobized silica was then added slowly to the acidified water while stirring was continued. During this process, a pH of around 5 was maintained by adding 10 sulphuric acid. Coagulation was carried out at room temperature. The mixture was then stirred for an additional 10 minutes. The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 pm filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear.
The filter was then dried. The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.08 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.92 of the silica dosage. The resulting wet masterbatch was dried at 70°C
in a vacuum oven.
Example 4 A butadiene-styrene-acrylonitrile terpolymer (NSBR) was used as the latex component. The rubber/silica masterbatch was based on the following recipe:
100.0 phr NSBR (10 % acrylonitrile, 28 % styrene, 62 % butadiene) 80.0 phr silica 6.4 phr Si69 4.0 phr N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride 1 ) Producing the hydrophobized silica suspension:

In order to obtain a 20 % silica suspension, 22.22 g silica were mixed with 88.88 g fully demineralised water. The silica suspension was heated to 50 °C
while being stirred. 0.11 N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state was added, followed by 0.83 g of a 2 % NaOH solution. 1.78 g of Si69 were then S added over a period of 30 minutes. After the addition of Si69, the mixture was stirred for a further 30 minutes. The treated silica suspension was next heated to 80 °C, and 1.00 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state was added over a period of S minutes. 0.78 g of a 10 % NaOH solution was then added over a period of 5 minutes. The mixture was stirred during all these process steps.
Lastly, fully demineralised water was added to dilute the hydrophobized silica suspension to 5 %.
2) Producing the preblend of latex and hydrophobized silica:
555.6 g of 5 % NSBR latex and the hydrophobized silica suspension were mixed for 10 minutes to form the preblend.
3) Coagulating the preblend of latex and hydrophobized silica:
The preblend of latex and hydrophobized silica was placed in a glass vessel equipped with a stirrer. While stirring the mixture, a 10 phr sodium dissolved in demineralised water was then slowly added. The pH was adjusted to 5 with 10 % sulphuric acid.
Coagulation was carried out at room temperature. The mixture was then stirred for an additional 10 minutes. The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 pm filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear. The filter was then dried. The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.61 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.39 % of the silica dosage. The resulting wet masterbatch was dried at 70°C in a vacuum oven.
Example 5 A butadiene-styrene-acrylonitrile terpolymer (NSBR) was used as the latex component. The rubber/silica masterbatch was based on the following recipe:
100.0 phr NSBR (21 % acrylonitrile, 21 % styrene, 58 % butadiene) 80.0 phr silica 6.4 phr Si69 4.0 phr N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride 1 ) Producing the hydrophobized silica suspension:
In order to obtain a 20 % silica suspension, 22.22 g silica were mixed with 88.88 g fully demineralised water. The silica suspension was heated to 50 °C
while agitation was maintained. Next, 0.11 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state was added, followed by 0.83 g of a 2 % NaOH solution. Then 1.78 g Si69 were then added over a period of 30 minutes. After the addition of Si69, the mixture was stirred for another 30 minutes. The treated silica suspension was heated to 80 °C, and 1.00 g N-oleyl-N-(trimethoxysilyl)propyl ammonium chloride in a molten state was added over a period of 5 minutes. After that, 0.78 g of a 10 NaOH solution was added over a period of 5 minutes. The mixture was stirred during all these process steps. Lastly, 333.3 g of fully demineralised water were then added to dilute the hydrophobized silica suspension to 5 %.
2) Producing the preblend of latex and hydrophobized silica:
555.6 g of 5 % NSBR latex and the hydrophobized silica suspension were mixed by agitating for 10 minutes to give the preblend.

3) Coagulating the preblend of latex and hydrophobized silica:
The preblend of latex and hydrophobized silica was placed in a glass vessel equipped with a stirrer. Approximately 10 phr of sodium chloride dissolved in demineralised water was then added to the stirred mixture. The pH was adjusted to 5 with 10 sulphuric acid. Coagulation was carried out at room temperature. The mixture was then stirred for another 10 minutes. The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 ~m filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear.
The filter was then dried. The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.04 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.96 % of the silica dosage. The resulting wet masterbatch was dried at 70°C
in a vacuum oven.
Comparative examples For the preparation of the comparative examples the silica grade HiSil~ 233 (PPG
Industries, USA) was again used.
The comparative examples were prepared according US 5,763.388 and EP 0 849 320.
Example 6 Example 6 corresponds to example 3 in US 5,763,388 and EP 0 849 320.
Krylene~ 1500 latex (ESBR, Bayer AG) was used as the latex.
The rubber/silica masterbatch was based on the following recipe:

100.0 phr Krylene~ 1500 (23.5 % styrene, 76.5 % butadiene) 20.0 phr aromatic oil 45.0 phr HiSil~ 233 silica 2.7 phr Silquest~ A-189 (corresponds to 6.0 pbw in relation to silica) The example was prepared according example 3 in US 5,763,388 and EP 0 849 320.
Preparation of the modified silica slurry: An aqueous solution of mercaptosilane was prepared by charging to a vessel 30 g Silquest~ A-189 (OSi Specialities), 1 ~
g isopropanol, 0.6 g of glacial acetic acid and 15 g dimineralized water. The cloudy mixture was agitated at high speed at room temperature until the mixture became clear (after about 20 minutes). 15 g of dimineralized water were then added to the mixture which made it cloudy again. Agitation was continued for approx. 15 minutes until the mixture again cleared.
A 1 liter vessel was charged with 337.5 g of a aqueous slurry of silica (HiSil~ 233) and stirred. 10.21 g of the aqueous solution of Silquest~ A-189 was than added with continued agitation, followed by the addition of 10% sodium hydroxide in order to adjust the pH to 7.8.
The stirred slurry was then heated to 77°C. The temperature was maintained at 77°C
for 4 hours, then allowed to cool to 60°C.
Blend of modified silica slurry with latex:
The modified silica slurry was charged to an agitated 2 1 vessel containing 632.91 g of 2~ SBR latex containing 23.7 wt% Krylene 1500 rubber stabilized with 9.50 g of antioxidant emulsion (containing 10 wt% Vulkanox 4020) and extended with 75 g oil emulsion containing 40 wt% of aromatic oil. After adding the modified silica slurry it was agitated for 10 minutes.

Coagulation of the modified silica slurry/latex blend:
An agitated 4 liter vessel was charged with 750 g of water followed by sufficient 1 sulphuric acid to adjust the pH to 4. Then the slurry latex blend was slowly added over 30 minutes. The pH was maintained at 4 by adding of 1% sulphuric acid.
The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 ym filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear. The filter was then dried.
The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.21 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.79 % of the silica dosage. The resulting wet masterbatch was dried at 70°C in a vacuum oven.
Example 7 A larger quantity of silica was used in this example, as might be appropiate in tire treads.
The rubber/silica masterbatch was based on the following recipe:
100.0 phr Krylene~ 1500 (23.5 % styrene, 76.5 % butadiene) 20.0 phr aromatic oil 80.0 phr HiSil~ 233 silica 4.8 phr Silquest~ A-189 (corresponds to 6.0 pbw in relation to silica) The example was carried out according example 3 in US 5,763,388 and EP 0 849 320.
The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting semm was removed by re-filtering through a 100 ~m filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear. The filter was then dried.
The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.19 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.81 % of the silica dosage. The resulting wet masterbatch was dried at 70°C in a vacuum oven.
Example 8 A larger quantity of Silquest~ A-189 was used in comparative example. The ratio of Silquest~ A-189 to rubber corresponds with the silane/rubber ratio as used in the examples 1 to 5 of this application.
The rubber/silica masterbatch in this comparative example was based on the following recipe:
100.0 phr Krylene~ 1500 (23.5 % styrene, 76.5 % butadiene) 20.0 phr aromatic oil 80.0 phr HiSil~ 233 silica 10.4 phr Silquest~ A-189 (corresponds to 13 pbw in relation to silica) The example was carried out according example 3 in US 5,763,388 and EP 0 849 320.
The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 ~m filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear. The filter was then dried.
The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.06 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.94 % of the silica dosage. The resulting wet masterbatch was dried at 70°C in a vacuum oven.
Example 9 Krynol~ 1712 latex (ESBR, Bayer AG) was used as in this example.
The rubber/silica masterbatch was based on the following recipe:
100.0 phr Krynol~ 1712 (23.5 % styrene, 76.5 % butadiene) 37.5 phr aromatic oil 80.0 phr HiSil~233 silica 4.8 phr Silquest~ A-189 (corresponds to 6.0 pbw in relation to silica) The example was carried out according example 3 in US 5.763,388 and EP 0 849 320.
The resulting masterbatch crumbs were homogeneous in appearance. They were isolated by screening through a 0,5 mm sieve. The very low amount of small masterbatch particles in the resulting serum was removed by re-filtering through a 100 ~m filter cloth. The resulting slightly cloudy serum was further filtered through a 5893 Blue Ribbon ashless filter paper circle to remove the small amount of suspended silica. The resulting serum was clear. The filter was then dried.
The difference in the weight of the dry filter before and after filtration corresponded to the amount of silica lost. A total of 0.25 % of the initial silica added was thus recovered, which meant that the masterbatch contained 99.75 % of the silica dosage. The resulting wet masterbatch was dried at 70°C in a vacuum oven.
Vulcanisation characteristics The vulcanisation characteristics were determined from examples 1 and 2 (according to the invention) and comparative examples 7, 8 and 9.
The following additives were added to the masterbatches of patent examples 1 and 2 (according to the invention) and comparative examples 2, 3 and 4:
Zn0 RS " 3.0 phr Stearic acid 1.0 phr Antilux~ 654'' 1.0 phr Vulkanox~ HS 3~ 1.5 phr Vulkanox~ 4020 ~~ 1.5 phr 1 S Vulkacit~ CZ 5~ 1.4 phr Vulkacit~ D 6' 2.0 phr Sulphur 1.6 phr '~ Zn0 RS, (zinc oxide, Bruggemann) z~ Antilux~ 654 (antiozonant wax, Rhein Chemie) 3~ Vulkanox~ HS ( TMQ, 2,2,4-trimethyl-1,2-dihydroquino-line, polymerized, Bayer AG) °' Vulkanox~ 4020 (6 PPD, N-(1,3-dimethyl-butyl)-N'-phenyl-p-phenylene-diamine, Bayer AG) 5' Vulkacit~ CZ (CBS, benzothiazyl-2-cyclohexyl-sulphenamide, Bayer AG) 6' Vulkacit~ D (DPG, Biphenyl guanidine, Bayer AG) Vulcanisation was carried out in the MDR (Moving Die Rheometer, Alpha Technologies, former Monsanto) at 170 °C. The following results were obtained:
Example Comp. Example Comp.Ex.2Comp.Ex.3 1 Ex. 4 2 t1 0 0,3 0,3 0,2 0,3 0,3 t90 4,7 14,5 4,4 6,4 15,1 S'max 18,2 15,6 25,7 17,4 17,8 The t10 value is the time taken in minutes for 10 % vulcanisation to be achieved.
The t90 value is the time taken in minutes for 90 % vulcanisation to be achieved.
Examples 1 and 2 and comparative examples 2, 3 and 4 have similar t10 values.
Examples 1 and 2 have markedly lower, and therefore better, t90 values than comparative examples 2, 3 and 4. The faster curing time is of economic importance.
The technical expert may, if so desired, further adjust the curing rate to suit the prevailing requirements by reducing the accelerator content. Such a reduction in additive content also makes the compound better value for money.

Claims (19)

1. least one of R19 and R20 has a carbon chain at least 8 carbon atoms in length uninterrupted by any heteroatoms and (3) admixing the particles of step (1) and (2) with one or more polymer latices to form a preblend.
2. 2. The process defined in claim 1, further comprising the steps of:
   (4) coagulating the preblend, and (5) drying the resultant product to give a polymer-filler masterbatch.
3. 3. The process defined in claim 1 or 2, wherein the compound of formula (I) is used in amounts in the range from 0.1 to 20 wt.% with respect to the weight of the particle in a dry state.
4. 4. The process defined in Claim 1 or 2, wherein the compound of formula (II) is used in amounts in the range from 0.1 to 20 wt.% with respect to the weight of the particle in a dry state.
5. 5. The process defined in Claim 1 or 2, wherein Steps (1) and (2) are conducted concurrently.
6. 6. The process defined in Claim 1 or 2, wherein Steps (1) and (2) are conducted sequentially.
7. 7. The process defined in Claim 1 or 2, wherein the compounds of Formulae I
   and II are the same compound.
8. 8. The process defined in Claim 1, wherein Step (1) comprises contacting an aqueous slurry of the particles with the compound of Formula I.
9. 9. The process defined in Claim 1 or 2, wherein the particles are silica particles.
10. 10. The process defined in Claim 1 or 2, wherein a coupling agent is added in an amount in the range from 0 to 20 wt.% with respect to the weight of the dry particle is used.
11. 11. The process defined in Claim 1, wherein the latices are those of one or more polymers selected from the group consisting of polybutadiene, butadiene styrene copolymers, isoprene styrene copolymers, butadiene isoprene styrene copolymers, butadiene acrylonitrile copolymers, butadiene acrylonitrile styrene copolymers, natural rubber, polystyrene, polychloroprene, ABS, polyvinylchloride, poly(acrylates) or mixtures thereof.
12. 12. The process defined in claim 11, characterized in that the polymer comprises functional groups.
13. 13. A filled latex produced by the process defined in claim 1.
14. 14. A masterbatch produced by the process defined in claim 2.
15. 15. A molded or extruded article made from the masterbatch of claim 14.
16. 16. A filled latex according to Claim 13, wherein said filled latex is used as paint.
17. 17. Use of the filled latex of Claim 13 in the manufacture of dipped goods, dental dams, balloons, speciality inner tubes, condoms, rubber gloves, paint, coated fabrics, coated paper, carpet backing or tire treads.
18. 18. Use of the masterbatch of Claim 14 in the manufacture of tire treads.
19. 19. The article of claim 15, wherein said article is a tire tread.