Claims
- 1. A pigmented composition which comprises
- (a) a rubber or plastic, and
- (b) an effective pigmenting amount of a copper phthalocyanine (CuPc) pigment prepared by converting crude CuPc to pigmentary CuPc by salt milling, solvent treatment or acid pasting in the presence of 0.5 to 30% by weight, based on the weight of crude CuPc, of crude trichlorophenoxy CuPc, obtained together with CuPc and chlorinated CuPc by replacing from 0.5 to 25% by weight of the phthalic anhydride used to prepare CuPc or chlorinated CuPc by an equivalent amount of 3,4,6-trichloro-5-phenoxy-2-cyanobenzoic acid alkyl or phenyl ester.
- 2. A composition according to claim 1 where in the pigment of component (b) the amount of trichlorophenoxy CuPc is from 2 to 10% by weight.
- 3. A pigmented composition which comprises
- (a) a rubber or plastic, and
- (b) an effective pigmenting amount of a copper phthalocyanine (CuPc) pigment prepared by (i) first converting crude CuPc into pigmentary form by dissolving in acid and then precipitating in water, and then (ii) milling the precipitate from step (i) in the presence of 0.5 to 30% by weight, based on the precipitate from step (i), of crude trichlorophenoxy CuPc to convert the mixture of pigments into the heat-stable pigmentary form.
- 4. A pigmented composition which comprises
- (a) a rubber or plastic, and
- (b) an effective pigmenting amount of a copper phthalocyanine (CuPc) pigment prepared by mixing crude CuPc with 0.5 to 30% by weight, based on the crude CuPc, of crude trichlorophenoxy CuPc, and then subjecting the mixture of crude pigments to salt milling or to acid pasting to convert the crude pigments into the heat-stable pigmentary form.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 8515600 |
Jun 1985 |
GBX |
|
Parent Case Info
This is a divisional of application Ser. No. 871,932, filed on June 9, 1986, now U.S. Pat. No. 4,694,078, issued on Sept. 15, 1987.
The present invention relates to the production of stabilised pigmentary copper phthalocyanine (CuPc).
GB 1558663 describes a process for the direct synthesis of pigmentary CuPc comprising adding a catalyst and/or crystal form controller from the beginning of the reaction. In the case of .alpha.-CuPc this may be inter alia, 1,2,4-trichloro-3-phenoxy CuPc. This compound is always present from the beginning of the reaction used to produce CuPc and pigmentary CuPc is obtained directly without the need for acid pasting or mechanical pulverisation.
In most cases however, which do not use the above direct synthesis method, crude CuPc is produced which then has to be converted into pigmentary CuPc.
Pigmentary CuPc is normally made from crude CuPc by known methods such as salt milling or acid pasting. Depending on the method used the product is .beta.-CuPc or the less stable .alpha.-CuPc. It is not often necessary to stabilise .beta.-CuPc but .alpha.-CuPc readily converts to the .beta.-CuPc in some applications if it is not stabilised. Stabilisation is normally carried out by adding chlorinated CuPc. However the amounts of chlorinated CuPc needed cause the red-shade-blue .alpha.-CuPc to become greener.
We have now surprisingly found that if crude CuPc is converted to pigmentary CuPc in the presence of trichlorophenoxy CuPc the resulting product is sufficiently heat stable to be used in colouring plastics and sufficiently solvent stable to be useful in colouring paints and inks, and moreover the red-shade-blue of .alpha.-CuPc is largely maintained.
The trichlorophenoxy CuPc used in the present invention is not a pure compound. It is prepared together with CuPc and/or chlorinated CuPc by replacing from 0.5 to 25% by weight of the phthalic anhydride used in the preparation of CuPc or chlorinated CuPc by an equivalent amount of 3,4,6-trichloro-5-phenoxy-2-cyanobenzoic acid alkyl or phenyl ester which may be prepared by the process described in British Patent Specification No. 1382925. Alkyl ester means preferably lower alkyl, e.g. ethyl or especially methyl ester
Accordingly the present invention provides a process for converting crude CuPc to pigmentary CuPc by methods known per se wherein 0.5 to 30% by weight based on the weight of CuPc, of trichlorophenocy CuPc, as defined above, is incorporated into the CuPc during processing.
The amount of trichlorophenoxy CuPc used in the process of the invention is preferably from 1-10% by weight.
The CuPc may be unchlorinated or it may contain up to 6%m for example 1-3% chlorine in the 2-position. Preferably the CuPc is unchlorinated.
The converstion of crude CuPc to pigmentary CuPc may be carried out by mixing the crude CuPc with the trichlorphenoxy CuPc and milling the mixture in the presence of a solid particulate grinding aid which is capable of being removed after milling. The solid particulate grinding aid may be an alkali metal or alkaline earth metal salt of a mineral acid such as sodium chloride or calcium chloride. The proportion of grinding aid may be rup to 500% by weight of the CuPc composition.
In addition a proportion of an alkali metal salt of an organic acid within the range of 2.5% to 25% by weight, based on the weight of grinding aid may be present during the grind. A suitable alkali metal salt is sodium acetate.
The product of this process is a stable pigmentary predominantly .alpha.-CuPc. If pigmentary .beta.-CuPc is wanted, the grinding may be carried out in the presence of 0.5-10% by weight, based on the weight of CuPc composition, of an organic liquid such as diethylaniline.
The ground material may also be treated with a polar at least partially water miscible, organic liquid such as isopropanol to produce a pigment with the desired particle size and enhanced colouristic properties.
A second process for converting the crude CuPc to pigmentary CuPc is to mix the CuPc with trichlorophenoxy CuPc, dissolve the mixture in or treat with concentrated sulphuric acid and then reprecipitate the CuPc by adding the acid solution or slurry into water.
The amount of concentrated sulphuric acid used may be from 200%-1500% based on the weight of CuPc composition and the process may be carried out at a temperature from 0.degree.-100.degree. C., preferably from 40.degree.-80.degree. C.
If desired a surfactant may be added to the water before addition of the acid solution. A suitable amount of surfactant is 0.5-10% by weight based on the weight of CuPc composition and a suitable surfactant is dodecylbenzene sulphonic acid.
The product of this process is a stable pigmentary .alpha.-CuPc. If desired this product may be subjected to milling, e.g. as described above to produce a pigment having a desired particle size.
Alternatively the crude CuPc may be converted to pigmentary CuPc by dissolving in concentrated sulphuric acid and reprecipitating by adding the solution to water. The product is then subjected to milling, e.g. as described above and the trichlorophenoxy CuPc is incorporated during the milling step.
The pigments produced by the present invention are strong and clean. They are sufficiently stable to heat to be suitable for colouring rubber or plastics such as PVC and polyolefines. They are also sufficiently stable to organic solvents to be useful in colouring paints and inks.
Accordingly the present invention also provides a rubber or plastics composition containing, as colourant, a stabilised pigmentary CuPc obtained by the process of the invention.
US Referenced Citations (3)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 1508856 |
Apr 1978 |
GBX |
| 1558663 |
Jan 1980 |
GBX |
Divisions (1)
|
Number |
Date |
Country |
| Parent |
871932 |
Jun 1986 |
|
Patent Grant
4801634
