JPS5943407B2 - Method for producing heat-resistant yellow pigment powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a heat-resistant yellow pigment powder, which is a composite oxide consisting of iron and zinc, which exhibits a bright yellow color and is used as a coloring pigment for coloring resins. The purpose of the present invention is to provide a heat-resistant yellow pigment that can minimize the degree of discoloration of colored resin during heat molding of the resin, and is particularly suitable as a coloring agent for polyolefin resins such as polyethylene and polypropylene. shall be.

Conventionally, yellow pigments made of inorganic substances, such as yellow lead, cadmium, and wax, are well known.

However, these pigments contain toxic lead, cadmium, etc. as main raw materials, and in recent years, they have been used to prevent pollution during the production and use of pigments. There is a strong desire for a non-polluting yellow pigment to replace the above pigments. On the other hand, as a non-polluting yellow pigment, yellow iron oxide (hydrous ferric oxide) has traditionally been used.
A complex oxide powder consisting of iron and zinc is known.

However, the former yellow iron oxide is very unstable to heat and has the disadvantage of poor heat resistance, making it unsuitable for use in hot molding or coloring resins. The latter composite oxide made of iron and zinc has a less yellowish tone, and when heat molding is used to color resin, the composite oxide itself made of iron and zinc does not resist heat. is a stable substance, but as described below, it discolors the resin when it is heated and molded. Therefore, for complex oxide pigments made of iron and zinc, increasing the vivid yellowness in color tone is referred to as ``bright yellowing''.

- In the case of colored resin, the coloring resin should not change color during heat molding. − is required. The present inventor has been developing a method for manufacturing a composite oxide consisting of iron and zinc that has been commonly used in the past for many years in order to improve the bright yellow color and heat resistance of the composite oxide consisting of iron and zinc. We have repeatedly investigated the relationship between various properties, color tone, and heat resistance of composite oxides made of iron and zinc.

In order to make a composite oxide consisting of iron and zinc bright yellow, a method has been adopted in which the composite oxide consisting of iron and zinc is finely pulverized using a powerful crusher.

However, when this material is used as a yellow pigment for coloring resin, it discolors the colored resin during heat molding of the resin. The inventor has determined that the cause of the discoloration of the colored resin during heat molding when using this fine powder pigment is as follows.
The fine particle powder obtained by pulverizing a composite oxide consisting of iron and zinc using a powerful pulverizer has distorted crystals, a large specific surface area, and an abnormally increased particle surface activity. Natsuta thought that the surface activity of these particles acts catalytically to change the color of the colored resin during heat molding of the resin. The present inventor studied to obtain a yellow pigment that does not have the above-mentioned catalytic action, and has no crystal distortion.
In addition, as a result of pursuing technological means to obtain a heat-resistant yellow pigment, which is a particle with a small specific surface area and reduced surface activity, we have developed a method of finely pulverizing a composite oxide consisting of iron and zinc. They discovered that the desired heat-resistant yellow pigment could be obtained by taking the technical step of annealing the material.

Furthermore, while the present inventor was conducting extensive research on the means of annealing pulverized materials, after adding zinc carbonate to a composite oxide consisting of iron and zinc,
By subjecting the finely pulverized material to annealing treatment, it is possible to obtain a yellow pigment that exhibits a bright yellow color that is equivalent to, or even brighter than, that of an additive-free heat-resistant yellow pigment, and also to obtain a yellow pigment that is easily loosened. It has also been found.

That is, the method of the present invention is a method for producing a heat-resistant yellow pigment powder by mixing iron oxide and zinc oxide or zinc carbonate, heating and baking the mixture, and then crushing the mixture to produce a heat-resistant yellow pigment powder. %, zinc oxide or zinc carbonate is 50.0 to 48.
After mixing 0 mol % and heating and baking at a temperature range of 800 to 1000°C, the obtained product is pulverized, or after heating and baking, 0.3% of zinc carbonate is added to the obtained product. ~
Add 3.0% by weight and grind, then 600-1000
This is a method for producing a heat-resistant yellow pigment powder, which is characterized by performing an annealing treatment in a temperature range of °C.

Next, the configuration and effects of the method of the present invention will be described.

First, the mixing ratio of iron oxide and zinc oxide or zinc carbonate, which are the starting materials in the method of the present invention, will be explained. In order to obtain the heat-resistant yellow pigment powder targeted by the present invention, 50.0 to 52.0 mol% of iron oxide and 50.0 to 52.0 mol% of zinc oxide are required.
．． It is necessary to mix 0 to 48.0 mol% of zinc oxide or zinc carbonate. Iron oxide is 52.
When the iron oxide content exceeds 0 mol%, that is, when the zinc oxide content is 48.0 mol% or less, a reddish pigment is likely to be obtained, and when the iron oxide content is 50.0 mol% or less, that is, when the zinc oxide content is Even if it exceeds 50.0 mol %, a reddish pigment is likely to be obtained, and it is difficult to obtain a heat-resistant yellow pigment exhibiting a bright yellow color, which is the object of the present invention, which is not preferable. Among the starting materials, iron oxide raw materials are Fe2O3, Fe3O4, Fe
Any of OOH etc. can be used.

Zinc oxide is commonly used as a raw material for zinc oxide to be mixed with iron oxide, but if it reacts with iron oxide within the firing temperature range of the method of the present invention to form a composite oxide consisting of iron and zinc. It can be anything. For example, zinc carbonate, zinc hydroxide, etc. can also be used. Next, to explain the firing temperature, in the method of the present invention, the firing temperature is 800 to 100.
The firing may be performed within a temperature range of 0°C.

If the firing temperature is 800°C or lower, the formation of the composite oxide is insufficient and the bright yellow pigment that is the object of the present invention cannot be obtained. On the other hand, if the firing temperature is 1000°C or higher, the composite oxide This is not preferable because it causes excessive particle growth due to firing, making subsequent pulverization difficult.

The pulverization performed after firing is performed using a composite oxide having a particle size suitable for use as a pigment, such as B. E. Specific surface area by T method is 4~6r
Any pulverizer that can produce a size of about 1 f/7 may be used, and for example, a pulverizer such as a vibrating mill can be used. Next, the most important annealing treatment for the method of the present invention will be explained.

In the present invention, annealing treatment is performed at a temperature range of 600 to 1000°C.

When annealing is performed at a temperature of 600°C or less,
Various properties of the finely pulverized particles of the composite oxide of iron and zinc obtained within the firing temperature range of the method of the present invention, such as distortion of the crystal, occur.

As a result, the composite oxide before annealing treatment, without affecting the large specific surface area of the particles, etc.
That is, particles with high surface activity are obtained, which is not preferable as a yellow pigment for coloring resins. On the other hand, 1000
When annealing is performed at a temperature of ℃ or higher, the surface activity of the composite oxide particles can be reduced, but on the other hand,
Particle growth or aggregation occurs due to sintering of the composite oxide, resulting in an undesirable reddish pigment.
Next, the addition of zinc carbonate will be explained.

The amount of zinc carbonate added must be 0.3 to 3.0% by weight based on the above-mentioned composite oxide consisting of iron and zinc. If the amount added is less than 0.3% by weight, the effect of addition will not be noticeable.

In order to obtain a heat-resistant yellow pigment powder exhibiting a bright yellow color, which is the object of the present invention, it is desirable to add 0.3 to 3.0% by weight based on the composite oxide. However, zinc oxide does not have the functions described below.

Next, the effects of the method of the present invention will be explained.

Since the heat-resistant yellow pigment powder obtained by the method of the present invention has been annealed, when used as a yellow pigment for resin coloring, compared to the conventional yellow pigment made of a composite oxide of iron and zinc, The degree of discoloration of the colored resin during heat molding of the resin can be minimized. In addition, the zinc carbonate added to the composite oxide has the function of a crushing aid, making it easier to crush the composite oxide, and it also makes it easier to crush the composite oxide. By having the function of suppressing growth or aggregation, it is possible to obtain a heat-resistant yellow pigment powder that has excellent heat resistance and exhibits a bright yellow color.

The heat resistance is particularly remarkable when the heat-resistant yellow-faced powder obtained by the present invention is used for polyolefin resins such as polyethylene and polypropylene. Next, an example,
The present invention will be specifically explained with reference to comparative examples. In each example, the preparation of a test piece for a heat resistance test, the heat resistance test method and conditions for a pigment are as follows.

(1) Heat resistance test, preparation of test piece 0.2y of heat-resistant yellow pigment was kneaded into 40 tons of low density polyethylene (F-019 manufactured by Ube Industries) using a hot roll at a temperature of 120°C, and the heat resistance test was carried out. Prepare a test piece for

(2) Heat resistance test method Wrap the test piece prepared according to the above method of preparing the test piece for heat resistance test in an aluminum wheel, place it in a gear type oven set at 280°C, and heat treat it for 10 minutes. Measure the color tone of the piece using a color difference meter.

Example 1 When mixing iron oxide (Fe2O3) powder and zinc oxide powder, Fe2O3: 51.0 mol%, ZnO: 4
After sufficiently mixing at a blending ratio of 9.0 mol% to obtain a mixture of 10107, the mixture was granulated and heated at 900°C in an electric furnace.
Fired for 2 hours.

After calcination, the product was ground in a vibrating mill, and then this material was
By performing an annealing treatment at 00°C for 2 hours, B. E.
Heat-resistant yellow pigment powder 9 with a specific surface area of 4.7 I/t by T method
Get 207. The ease with which this heat-resistant yellow pigment powder loosens is expressed as the blue residue.
0)", the result was 0.80%.

0.5 t of the obtained heat-resistant yellow pigment and 0.5 t of castor oil were kneaded in a Huba set muffler to make a paste, and 4.5 f of Kuriyaratsuka-1 was added to this, kneaded to form a paint, and applied on mirror coated paper with a 5mil applicator. The coating film obtained by applying and drying with
．． It exhibited a color tone corresponding to 0YR4.S/10.3. On the other hand, a test piece was prepared using the above-mentioned heat-resistant yellow pigment according to "Preparation of test piece for heat resistance test", and the color tone of this test piece was measured with a color difference meter. As a result, lightness L: 41.9 chromaticity a and b were a: 19.2 and b: 24.1, respectively.

Furthermore, the color tone of the test piece was measured using a color difference meter after a heat resistance test was carried out on the test piece according to the "Heat Resistance Test Method". :16.
2.b: 22.3.

Further, the total color difference (ΔE) obtained from the colorimetric values of the color tone of the test piece before and after the heat resistance test was 4.2. The total color difference ΔE was calculated according to ΔE=˜I]7Ts;7[Ma♂7. However, ΔL, ΔA, and Δb are the differences in the values of L, a, and b of the test piece before and after the heat resistance test. Examples 2 and 3 Types and mixing ratios of iron oxide powder and zinc compound powder as starting materials,
A heat-resistant yellow pigment powder was obtained in the same manner as in Example 1, except that the firing temperature and annealing temperature were variously changed, the color tone of the coating film was measured, and a test piece for a heat resistance test was prepared, and the test before and after the heat resistance test was performed. The color tone of the piece was measured using a color difference meter and the results are shown in the table.

Example 4 A mixture of 1004V of iron oxide powder and zinc oxide powder in the same mixing ratio as in Example 2 was prepared in the same manner as in Example 1.
The product was maintained at a temperature of 00° C. for 2 hours, and 57% of zinc carbonate was added to the obtained product (corresponding to 0.5% by weight with respect to the composite oxide consisting of iron and zinc).

) was added, then crushed in the same manner as in Example 1, and annealed to obtain a heat-resistant yellow pigment powder of 910V. The color tone of the test piece before and after the test was measured using a color difference meter, and the results are shown in the table. Examples 5 and 6 A heat-resistant yellow pigment powder was obtained in the same manner as in Example 4, except that the mixing ratio of the starting materials and the amount of zinc carbonate added were varied, and the color tone of the coating film was measured in the same manner as in Example 1. , further prepared a test piece for heat resistance test,
The color tone of the test piece before and after the heat resistance test was measured using a color difference meter, and the results are shown in the table.

Comparative Example 1 Fe20, powder: 51.0 mol%, ZnO powder: 49.
After sufficiently mixing at a mixing ratio of 0 mol% to obtain a 1020y mixture, the mixture was granulated and heated at 900°C in an electric furnace for 2
Keep firing for hours.

After calcination, the product was pulverized with a vibration mill, and B. E. A yellow pigment powder 9207 having a specific surface area of 5.3 I/7 was obtained by the T method.
The color tone of the coating film was measured using the obtained yellow pigment powder in the same manner as in Example 1, and a test piece for heat resistance test was also prepared, and the color tone of the test piece before and after the heat resistance test was measured using a color difference meter. The results are shown in the table. Comparative Example 2 A yellow pigment powder was obtained in the same manner as in Example 1 except that the annealing temperature was changed to 500°C.

Claims (1)

[Claims] 1. A method for producing a heat-resistant yellow pigment powder by mixing iron oxide and zinc oxide or zinc carbonate, heating and firing the mixture, and then pulverizing the mixture, comprising 50.0 to 52.0 moles of iron oxide. %, 50.0 to 48.0 mol % of zinc oxide or zinc carbonate is mixed and fired at a temperature range of 800 to 1000°C. A method for producing a heat-resistant yellow pigment powder, characterized by performing an annealing treatment in a temperature range of . 2. The method for producing a heat-resistant yellow pigment powder according to claim 1, wherein the temperature range of the annealing treatment is 650 to 800°C. 3 In a method for producing a heat-resistant yellow pigment powder by mixing iron oxide and zinc oxide or zinc carbonate, heating and baking the mixture, and then pulverizing the mixture, zinc oxide is added to 50.0 to 52.0 mol% of iron oxide. Or, after mixing 50.0 to 48.0 mol% of zinc carbonate and heating and baking in a temperature range of 800 to 1000°C, 0.3 to 3.0 weight of zinc carbonate is added to the obtained product. A method for producing a heat-resistant yellow pigment powder, which comprises adding % of the powder, pulverizing the powder, and then annealing in a temperature range of 600 to 1000°C. 4. The method for producing a heat-resistant yellow pigment powder according to claim 3, wherein the temperature range of the annealing treatment is 650 to 800°C.