JPS5933618B2 - Production method of gamma quinacridone - Google Patents

Description

[Detailed description of the invention] This invention relates to quinacridone pigments.

More specifically, the present invention relates to gamma crystal phase quinacridone (
Regarding the production method (hereinafter referred to as gamma quinacridone). Linear quinacridones have the structural formula α:°C (D) and exist in many crystalline phases including α, β, and γ phases, as disclosed in US Pat. No. 2,844,581.

Gamma quinacridone has recently found ready markets in the automotive and construction industries due to the fact that this pigment produces deep red metallic finishes in the quinacridone color range.

Previously, gamma quinacridone was produced commercially from quinacridone by oxidizing dihydroquinacridone and then grinding it.
See US Pat. No. 2,844,581.

Other patents in this same general field include U.S. Pat.
60510, 3257405 and 3342823
There is a number.

Milling of the quinacridone to yield gamma quinacridone is of course an additional step in the production of this pigment and requires additional energy input, time, equipment, etc. However, until now, the only known method for producing gamma quinacridone involved milling the quinacridone. The object of the present invention is to produce gamma quinacridone.

Another object of this invention is to make gamma quinacridone directly from the ring closure of dianilinoterephthalic acid. These and other objectives will become apparent from the description below. According to the invention, from 1 to 20% by weight of di(ortho-substituted)
heating a mixture of dianilinoterephthalic acids containing anilinoterephthalic acid to about 70° C. or higher in the presence of polyphosphoric acid;
A method of making gamma quinacridone is provided which comprises thereafter diluting the reaction mixture with water or a water-miscible diluent to recover the precipitated gamma quinacridone.

When operating according to the invention, i.e. in the ring closure of dianilinoterephthalic acids in the presence of ortho-substituted dianilinoterephthalic acids, the product produced by immersion or dilution in water or water-miscible organic liquids is An X-ray diffraction image that is generally accepted as identifying quinacridone, i.e., gamma-crystalline quinacridone.
It has been found that a line diffraction pattern appears.

The process of the present invention thus provides a direct method for the production of gamma quinacridone, obviating the need for the special grinding steps heretofore required for the production of this crystalline phase quinacridone pigment. The gamma quinacridone pigments made by the process of this invention have excellent outdoor durability and are useful for coloring automotive finishes, inks, and house paints. This is particularly valuable in the production of red architectural finishes and clear automotive metal finishes. The process of the present invention provides a simple, economical route to gamma quinacridone that eliminates the need for some of the steps previously thought to be necessary to produce gamma crystalline phase quinacridone. The method of the present invention further demonstrates that the current quinacridone technology is that soaking a polyphosphoric acid solution of an unsubstituted quinacridone containing 1-20% by weight of diortho-substituted quinacridone with water or a water-miscible organic liquid produces a violet beta phase. The formation of gamma quinacridone was completely unexpected since it is normally expected that quinacridone would be formed. However, this is not the case in the present case; the quinacridone produced by operating within the scope of the invention exhibits a gamma-type X-ray pattern. In the practice of this invention, dianilinoterephthalic acid is mixed with 1 to 20% by weight of di(ortho-substituted)anilinoterephthalic acid and dissolved in polyphosphoric acid.

The use of polyphosphoric acid as a ring-closing agent is described in U.S. Pat. No. 32,574.
No. 05 and No. 3,342,823 are well known in quinacridone technology. As shown in the prior art, polyphosphoric acid is at least 100% acid (H3PO4
) content. Preferably the concentration of polyphosphoric acid is 114-120%. The mixture was heated to 70°C while being stirred.
Above, it is preferably heated at a temperature of 80 to 120°C.
Once the ring is closed, which typically takes 4 to 16 hours, the mixture is cooled to below 100 DEG C. and then diluted with water or a water-miscible organic liquid. Addition of water or a miscible organic liquid results in a slurry, which is then heated at reflux temperature and, if organic liquids are used, placed in water;
Filter, wash to remove acid, boil with caustic soda to remove traces of acid, filter, wash to remove alkali, and dry to obtain a red solid gamma phase quinacridone pigment. The water-miscible organic liquids useful in the process of the present invention result in the production of highly attractive quinacridone colors.

Among the liquids that may be named are methanol, ethanol,
Alcohols such as isopropanol, glycerol, diacetone alcohol, diethylene glycol and the like, or ketones such as acetone. Preferably alcohol is used as the organic liquid miscible with the water used for steeping the mixture, and most preferably methanol is used for this purpose. As indicated above, the amount of di(ortho-substituted)anilinoterephthalic acid is from 1 to 20% by weight of the starting dianilinoterephthalic acid.

When the replacement material is present in an amount of 1 to 10% by weight, the reaction product is preferably precipitated with an alcohol such as methanol, whereas when the replacement material is in an amount of about 10 to 20% by weight, the reaction product is preferably precipitated with an alcohol such as methanol. is precipitated with water.
Amounts greater than 20% yielded products that showed significant changes in the X-ray diagram, indicating that no gamma quinacridone was produced as desired.

Similarly, when less than 10% by weight is used and the reaction product is precipitated with water alone, the X-ray diffraction pattern shows that the gamma quinacridone is the desired amount, unlike precipitation with water-miscible organic liquids. This shows that it is not generated as shown below. [Ortho-substituted] dianilinoterephthalic acid is 4 of dianilinoterephthalic acid.
- Means substitution at the 11th position. Halogen substituents such as chlorine, fluorine, bromine, iodine and especially chlorine are preferred substituents according to the invention. Other exemplary substituents which may be mentioned include alkyl, i.e. methyl, ethyl, propyl and butyl, alkoxy, i.e. methoxy, ethoxy, propoxy and butoxy, and also halogenated alkyl, i.e. mono-, di- and trihalogenated alkyl, and carboalkoxy having 1 to 4 carbon atoms, such as carbomethoxy and carboethoxy. The following examples are given by way of example only.

Example 1 26.9 parts of dianilinoterephthalic acid and 1.0 part of di(orthochloro)anilinoterephthalic acid are added to 195 parts of polyphosphoric acid with an acid concentration of 118%.

The mixture was heated at 102-105°C for 16 hours and then at 90°C.
Cool to ℃. The cooled mixture was diluted with 35°C methanol 3
Inject into 75 parts. The resulting slurry was refluxed for 1 hour, then poured into 600 parts of water, heated to 60°C for 30 minutes, then filtered, washed free of acid, and mixed with 75 parts of 50% sodium hydroxide solution and 1500 parts of water. Slurry again in 1 minute and boil for 1 hour. After filtration, wash to remove alkali, and adjust the wet compressed cake to pH 3-3 with dilute hydrochloric acid.
．． The slurry was slurried in 750 parts of water at 70° C. and heated at 70° C. for 30 minutes. P filter, washing to remove acid and drying overnight at 180 DEG C. gives a red solid 25-257 with an X-ray profile essentially of gamma quinacridone (all parts shown are by weight unless otherwise specified). Example 2 25.1 parts of dianilinoterephthalic acid and 2.74 parts of di(ortho-chloroanilino)terephthalic acid were added to 195 parts of polyphosphoric acid with an acid concentration of 116.6%.

Claims (1)

[Claims] 1. Heating a mixture of dianilinoterephthalic acids containing 1 to 20% by weight of di(ortho-substituted)anilinoterephthalic acid in the presence of polyphosphoric acid to a temperature above about 70°C, and then mixing the reaction mixture with water or water. A method for producing gamma quinacridone, which comprises recovering precipitated gamma quinacridone by diluting it with a diluent.