Titanium compositions

A new organotitanate which is a reaction product of a titanium orthoester and at least a monoalkyl phosphate in which the alkyl group contains up to 6 carbon atoms and in which the total molar ratio P:Ti in the product is less than 2. The monoalkyl phosphates preferably contain up to 5 carbon atoms in the alkyl group and the organotitanate reaction product can also be prepared from a dialkyl phosphate in addition to the monoalkyl phosphate. Most preferably the alkyl group of the titanium orthoester is either an isopropyl group or a butyl group. The new reaction products are of use as adhesion promoters in printing inks.

This invention relates to titanium compositions and particularly to 
reaction products which are organotitanates. 
According to the invention an organotitanate comprises the reaction product 
of a titanium orthoester and at least a monoalkyl phosphate in which the 
alkyl group contains up to 6 carbon atoms and in which the total molar 
ratio P:Ti in the product is less than 2. 
The titanates of the invention are the reaction products of a titanium 
orthoester, and at least a monoalkyl phosphate. If desired a dialkyl 
phosphate can also be used in addition to the monoalkyl phosphate. 
Generally speaking the titanium orthoester will have the general formula 
Ti(OR).sub.4 in which R represents an alkyl group usually containing up to 
10 carbon atoms. Preferably R represents an alkyl group containing 3 or 4 
carbon atoms and although it is possible that within one molecule of the 
orthoester different alkyl groups may be present usually they are the 
same. 
The monoalkyl phosphate generally has a formula (R.sub.1 O)PO(OH).sub.2 in 
which R.sub.1 represents an alkyl group containing up to 6 carbon atoms, 
preferably up to 5 carbon atoms. The dialkyl phosphate if used generally 
has the formula (R.sub.2 O)(R.sub.3 O)PO(OH) in which R.sub.2 and R.sub.3 
each represents an alkyl group usually containing up to 6 carbon atoms and 
preferably containing up to 5 carbon atoms. Usually but not necessarily 
R.sub.1, R.sub.2 and R.sub.3 are identical. 
Most preferably the alkyl group of the titanium orthoester is an isopropyl 
or butyl group. 
The organotitanates of the present invention are reaction products of the 
titanium orthoester in which the total molar ratio P:Ti in the product is 
less than 2 and preferably less than 1.5. 
The alkyl phosphate is added to titanium orthoester or vice-versa to 
produce the desired reaction product. The reaction can be carried out at 
room temperature if desired and with stirring and cooling if necessary. 
The dialkyl phosphate if used can be added separately or with the 
monoalkyl phosphate. 
The new reaction products are of value when used as adhesion promoters in 
printing inks. A printing ink basically consists of a polymeric binder, a 
solvent therefor, and usually a pigment and/or a dye. The adhesion 
promoter is required to promote crosslinking of the polymeric binder and 
adhesion of the ink to different substrates. The inks which are of 
particular interest are the flexographic or gravure inks in which the 
polymeric binder is cross-linkable and is dissolved in an appropriate 
organic solvent therefor. Typical binders usable in such inks are those 
based on nitrocellulose or ester type modified celluloses, e.g. cellulose 
acetate propionate. Often such polymeric binders are employed in mixed 
form with polyamides, polyurethanes and/or other resins. 
The ink usually contains one or more pigments and/or one or more dyes and 
typical pigments which can be used are the coloured inorganic pigments, 
white inorganic pigments and coloured organic pigments. Organic dyes can 
be used to render the ink the appropriate colour and often are used in 
conjunction with an opacifying white inorganic pigment such as titanium 
dioxide.

The invention is illustrated in the following Examples: 
EXAMPLE 1 
To a round bottomed flask equipped with a stirrer, condenser and dropping 
funnel and containing 284 gms of tetraisopropyl titanate there was slowly 
added from the funnel 203 gms of a commercial mixture of approximately 
equi-molar proportions of monoamyl phosphate and diamyl phosphate. The 
contents were stirred with the flask in a cooling bath until the addition 
was complete. 
An ink was made from the following ingredients in a ball mill: 
______________________________________ 
parts by weight 
______________________________________ 
Nitrocellulose (Dry wt) 
5.05 
Polyurethane resin 6.72 
Rutile TiO.sub.2 15.54 
Dicyclohexyl phthalate 
5.46 
Polyethylene wax 2.00 
Isopropanol 2.16 
Industrial methylated spirits 
22.02 
Ethyl acetate 26.17 
Toluene 14.88 
100.00 
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To 100 parts by weight of the above ink there was added 1 part by weight of 
the reaction product by weight of the prepared reaction product. 
The so prepared ink was used to prepare and test a printed strip of 
co-extruded polyethylene/polypropylene and for comparison the ink without 
added reaction product was used to print an adjacent area of the strip. A 
sticky tape, (7.6 cm wide) was applied to the printed strip to contact 
both ink surfaces and pressure applied to ensure good contact. 
The tape was then quickly removed from both inks simultaneously and a 
visual inspection made of the strip. It was apparent that little or no ink 
containing the titanate was removed whereas virtually all the unmodified 
ink was removed by the sticky tape. 
Samples of co-extrudate printed with both inks were mounted between sheets 
of aluminium foil and heated to approximately 160.degree. C. for 10 
seconds. The heated samples were allowed to cool and the foil removed and 
inspected. It was clear that less of the modified ink had become 
transferred to the foil than that of the unmodified ink. 
EXAMPLE 2 
A titanate was prepared in a manner similar to that described in Example 1 
from 340 gms of tetra-n-butyl titanate and 182 gms of an approximately 
equi-molar mix of monobutyl phosphate and dibutyl phosphate. 
The titanate was used to prepare an ink in a similar manner to that of 
Example 1 and tested similarly. 
Again the modified ink exhibited improved adhesion and heat resisting 
properties. 
EXAMPLE 3 
A titanate was prepared in apparatus as described in Example 1 from 340 gms 
of tetra-n-butyl titanate and 154 gms of monobutyl phosphate dissolved in 
308 gms of industrial methylated spirits with vigorous stirring. 
The titanate solution was used to prepare an ink similar to that of Example 
1 except that 1.5 parts by weight of the solution was added and tested 
similarly. 
The modified ink was shown to have similar improved properties to those of 
Examples 1 and 2. 
EXAMPLE 4 
A titanate was prepared in apparatus as described in Example 1 from 284 gms 
of tetraisopropyl titanate and 161 gms of an approximately equi-molar mix 
of monoisopropyl phosphate and diisopropyl phosphate dissolved in 94 gms 
of industrial methylated spirits with vigorous stirring. 
The titanate obtained was used to prepare an ink in a similar manner to 
that of Example 1 and tested similarly. 
The modified ink was shown to have similar improved properties to those of 
the modified inks of Examples 1, 2 and 3.