JPS6172069A - Modified silica-coated lead chromate pigment composition and its preparation - Google Patents

Abstract

PURPOSE:To obtains the titled composition having decreased flying tendency and improved light resistance, chemical resistance and heat resistance, by adding an organic silicon compound to a silica-coated lead chromate pigment, mixing and heating the mixture in the presence or absence of water or organic solvent, and if necessary, drying the product. CONSTITUTION:The objective composition can be produced by adding (A) an organic silicon compound such as (un)modified silicone oil to (B) a silica-coated lead chromate pigment prepared by applying continuous film of amorphous silica to the surface of lead chromate pigment particle, uniformly mixing the mixture under heating in the presence or absence of (C) water or an organic solvent, and if necessary, drying the product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead chromate pigment composition having improved anti-scattering properties, light resistance, chemical resistance, and heat resistance in terms of q#, and a method for producing the same. Lead chromate pigment is ``Brimrose Yellow'', which has lead chromate as its main component and has an orthorhombic green-yellow color.

"Medium Φ Yellow", which has a monoclinic crystal shape with a wide range of hues from yellow to orange; "Molybdate Orange", which has a tetragonal crystal shape, and has a wide range of hues from yellow to orange;
It is widely used in paints, printing inks, and for coloring synthetic resins as an excellent pigment with a clear green-yellow to red hue and a large hidden pigment.

The object of the present invention is to provide a lead chromate pigment composition with improved pigment properties suitable for these uses.

[Conventional technology]

However, these lead chromate pigments have inherent drawbacks.

That is, when lead chromate pigments come into contact with acids, alkalis, or sulfides in the atmosphere, or are exposed to heat or ultraviolet rays, their inherent color tone changes and discolors. The reason for this is that the former is thought to be caused by the dissolution and/or reaction of lead chromate, which is a so-called chemical resistance problem, while the latter is thought to be caused by the reduction phenomenon of hexavalent chromium. So-called.

The problem is heat resistance.

In recent years, many modified lead chromate pigments that solve these drawbacks have been proposed and put into practice.

For example, there are silica-coated lead chromate pigments that improve pigment properties by forming a continuous silica film on the surface of lead chromate pigment particles (Tokukoku Shodar No. 9555, Tokko Shodal No. 9555,
I&-,? Da7zat Publication).

To further improve this, there is a silica-zirconium double layer lead chromate pigment composition in which a thin layer of zirconium oxide is interposed between the silica film and the surface of the pigment particles (Japanese Patent Publication No. 5O-14T31).

Although these silica-coated lead chromate pigments have significantly improved the various resistances of pigments, they do not have resistance under friction when used, so they were further developed in Japanese Patent Publication No. 444 to improve this.
-II2713, JP-A-33-7104, JP-A-3! -75OAj publication, JP-A-Sho! ; & -1
06t&- Publication No. ζ As represented by alkaline earth metal salts, organic phosphates, long-chain alkylamines, salts, long-chain secondary ammonium salts, or thermoplastic resins of rosin acid or higher aliphatic acids, etc. Some are surface-treated with silica-coated lead chromate pigments.

[Problem that the invention seeks to solve]

Previously proposed modifications of silica-coated lead chromate using organic surface treatment agents each have their own merits and demerits, and a comprehensive evaluation of untreated silica-coated lead chromate pigments and various resistances shows that little improvement is expected. The current situation is that when using them, we have no choice but to adjust their characteristics and use them accordingly.

For example, silica-coated lead chromate treated with lead rosinate or higher fatty acid salts has some improvement in heat resistance, but other resistances tend to deteriorate, and it is not only dust-producing, but also difficult to store. There is a risk of ignition.

The present invention was developed with the aim of more comprehensively improving silica-coated lead chromate pigments, and as a result of intensive research aimed at improving the affinity between the silica film and the pigment, it was discovered that the silica-coated lead chromate pigments were brought into close contact with an organosilicon compound. As a result, the present invention was completed based on the finding that a very stable lead romate pigment composition which overcomes the drawbacks of the prior art can be obtained.

[Means and effects for solving the problems] The gist of the present invention is to provide a silica-coated lead chromate pigment in which a substantially continuous amorphous silica film is formed on the surface of the lead chromate pigment particles. This is a modified lead chromate pigment composition consisting essentially of the above-mentioned pigment, and the coated pigment is surface-treated with an organosilicon compound.

The chromium lead pigment in the present invention refers to lead chromate (Pb
It is a pigment whose main component is 0r04), and the color index (Co1our engineering naex) Nl! L7740
0°77/aO/, 77603 and 17403 [Color Index 2nd edition (/
Lt 6th year)].

The above pigment is a pigment whose main component is lead chromate, which is well known to those skilled in the art, and the history of its production does not matter in the present invention.

In addition, in the production of lead chromate pigments, small amounts of metal oxides (defined as including hydrated oxides) are added to improve the efficiency of the stabilization operation of pigment crystal particles or to improve the bonding strength with the silica film. However, lead chromate pigments in the present invention include lead chromate pigments on which metal oxides have been deposited, regardless of the purpose.

Examples of metal oxides include zirconium.

Seven or more metal oxides selected from aluminum, titanium, cerium, magnesium, antimony, etc. The amount varies depending on the purpose of deposition, but in most cases it is 10,776 or less in terms of anhydride per total weight, Preferably it is in the range of 5 to 5%.

A dense, continuous, amorphous silica film may be formed on the lead chromate pigment by any known method.

That is, it is carried out by adding or forming an active silica sol to a lead chromate pigment slurry to deposit fine silica particles on the surface of the pigment particles.

When depositing silica, it is desirable to have pigment particles as uniformly and sufficiently dispersed as possible, so it is recommended to perform sufficient vigorous stirring or shear dispersion using a homogenizer, Waring blender, or colloid mill. .

Also, as a dispersant, for example, sodium hexametaphosphate,
It is also desirable to add a small amount of sodium silicate or the like.

After the preparation of a uniform pigment slurry, the p of the slurry is
The silica sol, in other words "activated silica", is deposited under heating, preferably at 0 to 90 DEG C. The method of depositing "activated silica" is defined in Japanese Patent Publication No. 4tA-43JJ.1 This method is also followed in the present invention, but in many cases, it is gradually added by simultaneously adding an aqueous solution of sodium silicate and sulfuric acid. Preferably, the reaction causes the resulting activated silica to be deposited on the surface of the lead chromate pigment particles.

After the silica coating treatment for lead chromate pigments, a known flocculant is added to perform solid-liquid separation in order to increase the recovery efficiency of solid-liquid separation.In this case, when aluminum sulfate or aluminum alum is used as the flocculant, Due to hydrolysis lζ, hydrated alumina is further deposited on the silica, so the silica film formed in the present invention contains hydrated oxides such as alumina mixed in from the inorganic flocculant.

The amount of silica based on such silica deposits varies depending on the intended use of the pigment, but is generally about S10. 5 to 30%, preferably 10-S%.

The reason for this is that if it is less than 7%, the effect of the silica coating is insufficient, while if it exceeds JO%, the pigment concentration will decrease.

In the present invention, the surface of the silica-coated lead chromate pigment is treated by adding an organosilicon compound to the pigment.

This surface treatment varies depending on the type of organosilicon compound used, but is usually prepared by adding an organosilicon compound to an aqueous slurry, filter cake, or dry powder of silica-coated lead chromate pigment together with an organic solvent or emulsifier as necessary. After thoroughly mixing with i, dehydrate or remove the solvent to 100%
This can be done by heating at ~/30°C.

Note that the separation and drying steps can be omitted during the mixing treatment, or by natural drying after mixing, or when the organic solvent can be removed.

The mixing means used in the above surface treatment may be uniformly carried out using a desired mixer such as an ordinary stirrer, homogenizer, colloid mill, homomixer, screw mixer, hard mixer, or Henschel mixer.

The organosilicon compound that can be used in the present invention in such surface treatment improves the affinity between the silica film and the lead chromate pigment, but is not particularly limited as long as it can be expected to improve the pigment properties by adding the compound. Examples include the following compounds, although they are not limited to

Typical silane coupling agents include methyltochlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, γ-chloropropyltrimethoxysilane, r-chloropropylmethyldimethoxysilane, and r-(2-aminoethyl)aminopropyltrimethoxysilane. Methoxysilane, 1-(z-aminoethyl)aminopropylmethyldimethoxysilane.

r-methacryloxypropyltrimethoxysilane, N-
β-(N-vinylbenzylaminoethyl)-r-7minopropyltrimethoxysilane, r-glycidoxypropyltrimethoxysilane, r-mercaptopropyltrimethoxysilane, methyltrimethoxysilane.

Methyltriethoxysilane, vinyltriacetoxysilane, hexamethyldisilazane, vinyltris(methoxyethoxy)silane, vinyltrimethoxysilane.

Vinyltriethoxysilane, octadecyldimethyl [,
? -(trimethoxysilyl)propyl]ammonium chloride, r-mercaptopropylmethyldimethoxysilane, r-anilinopropyltrimethoxysilane, etc.
Dimethylpolysiloxane and methylphenylpolysiloxane are representative silicone oils.

Examples include methyl hydrogen polysiloxane. or.

Epoxy-modified products, alkyl-modified products, amino-modified products, carboxyl-modified products, alcohol-modified products, fluorine-modified products, alkyl aralkyl polyether-modified products, epoxy polyether-modified products, polyether-modified products, or modified or unmodified silicone oils. Examples include silicone resin.

In addition, two or more of the above compounds can be used in combination, if necessary.

In addition, the amount of the above compound used is 0 per total weight of finished pigment.
．． 3-9-04. Preferably, a range of / to 30% is appropriate.

The reason for this is that if the amount is less than t%, the modification effect of the silica-coated lead chromate pigment is insufficient, and if it exceeds 30% (!: the modification effect is not expected for the amount used, and it is not good).

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples, where all parts are by weight.

Example / Slurry No. 5183 Sodium silicate (Sin, : Cobb weight %, molar ratio 5iO1/N
a, O=, 7. J) After adding 1142 parts, stir and disperse uniformly at room temperature. If desired, this pigment dispersion slurry may be processed using a homogenizer [manufactured by Kokusan Seiko Co., Ltd., Barrel].
Perform dispersion treatment using a shearing machine such as Homogenizer No. 1]. Next, the temperature of this slurry was maintained at 3°C, and an aqueous sodium hydroxide solution was added as needed to adjust the pH to 9.
．． Adjust to 0-10.0.

Next, as SIO2, add 100 parts of a 5% by weight sodium silicate aqueous solution (liquid A), J! 72,000 parts by weight of an aqueous sulfuric acid solution (liquid B) is simultaneously added to the slurry prepared during stirring over a period of about 3 hours. A liquid and B
While the liquid is being added, the temperature of the slurry is maintained at j'Q, and the pH is controlled to be 9.0-/0.0. After performing the silica coating treatment in this way, in order to efficiently recover the treated product, g, 2000 parts of a 3% by weight aqueous aluminum sulfate solution were added, and a sodium hydroxide aqueous solution t trowel p) Then, wash with water using the usual method.
3-00 parts of silica-coated lead chromate pigment was obtained by pulverization after filtration and drying steps.

Next, 2300 parts of the obtained silica-coated lead chromate pigment and r-methacryloxypropyltrimethoxysilane SO
and an organosilicon compound prepared by dissolving a mixture of 1 part and methyl hydrogen polysiloxane (alcohol-modified product) in xylene using a Henschel mixer [manufactured by Mitsui Miike Kakoki Co., Ltd.].

FM#7B) for 10 minutes. The temperature inside the mixer at this time was 90°C.

After mixing, the solvent was completely removed by air drying to obtain a modified silica-coated lead chromate pigment composition.

Example: Pigment 230 subjected to silica coating treatment similar to Example 1
0 parts of an organosilicon compound (polyether-modified silicone oil: EJHJ711A manufactured by Tone Silicone Co., Ltd.) is slowly added to an aqueous slurry containing 0 parts, and thoroughly stirred and mixed to effect intimate contact treatment. Next, a modified silica-coated lead chromate pigment composition was obtained through filtration, drying (730° C.) and pulverization.

Example J Sodium dichromate C'NLt'rzOy"
A sodium chromate aqueous solution prepared by dissolving /11,1 part of sodium hydroxide and 36/part of sodium hydroxide in water to make a total amount of 20,000 parts was mixed with a lead nitrate aqueous solution of -0,000 parts at a temperature of 50°C /4t and a weight percent of lead nitrate. The mixture is gradually added and reacted for about 30 minutes while stirring. After further stirring for 30 minutes, ZrO,
37.6 parts of a dilute aqueous solution of zirconium sulfate was gradually added to the solution, followed by addition of an aqueous solution of zirconium carbonate to adjust the pH to 4.4'. Furthermore, a zirconium oxide-coated lead chromate pigment was obtained by washing with water, filtering, drying and pulverizing in a conventional manner.

Subsequently, 2,300 parts of this zirconium oxide-coated lead chromate pigment was subjected to a silica coating treatment in the same manner as in Example 1 to obtain a silica-coated lead chromate pigment containing zirconium oxide.

Next, 2,300 parts of this pigment, 100 parts of r-(2-aminoethyl)aminopropylmethyldimethoxysilane, and 30 parts of a silicone resin liquid with a nonvolatile content of 3% by weight (
SR Co1I10: Tone, manufactured by Silicone Co., Ltd.] was subjected to a close contact treatment for 70 minutes in a Henschel mixer, and then air-dried to obtain a modified silica-coated lead chromate pigment composition.

Examples D to G Each modified silica-coated lead chromate pigment was prepared in exactly the same manner as in Example 3, except that the intervening oxide and the organosilicon compound diluted with a solvent were used as shown in the table below. A composition was obtained.

Example 9 Brimrose color lead chromate pigment (CI-77AOJ
) 2! A silica-coated brimrose color lead chromate pigment is obtained using r00 parts in the same manner as in Example. Then,
700 parts of this pulverized prepared pigment was diluted with 5% by weight wLj? of dimethylpolysiloxane emulsion (Sytgqo/: product of h-Resilicone Co., Ltd.). 00 parts and stirred and mixed for 30 minutes at a temperature of S°C.

Next, the slurry was taken from house to house and dried at 10° C. for 3 hours to obtain a modified silica-coated lead chromate pigment composition.

Example/θ Molybdate orange (chrome vermilion).

A silica-coated molybdate orange pigment was obtained by the same silica treatment procedure as in Example 1 using CI-N [17760S). Next, r-mercaptopropyltrimethoxysilane/30 parts of the pulverized pigment was added to 30 parts of the pulverized pigment.
part and iso part of alcohol-modified silicone oil were intimately mixed with a small amount of organic solvent in a Henschel mixer for /θ minutes. After mixing, a modified silica coated molybdate orange pigment composition was obtained.

Comparative Example/-9 The treatment with the organosilicon compound in Example 1 and Examples J to 10 was carried out in the same manner as in the previous example except that the treatment with the organosilicon compound in Examples 1 and J to 10 was not performed. Each uncoated silica-coated lead chromate pigment was prepared.

Comparative Example 10 Based on the method of Example 1 of Japanese Patent Publication Shoda 6-da 2'ilJ, a rosin soap-treated silica-coated lead chromate pigment composition was obtained as follows. Lead chromate pigment (CI-1k17
7400) A slurry of 723 parts and t000 parts of water is stirred at room temperature until homogeneous. Next, 16.7 parts of sodium silicate solution No. 3183 is added to this while stirring.

After passing this slurry through a homogenizer to disperse the pigment, the temperature of the slurry was raised to 90-? Adjust the pH by heating to j'Q and adding sodium hydroxide if necessary. ,
Adjust to 0-9.5.

Next, a solution prepared by diluting 96 parts of IJ chromium solution with water to a volume equivalent to 300 parts of water, and 9 parts of sulfur
(6%)/$, and 1.70 parts of water containing da part are simultaneously added into the prepared slurry at a constant rate of about 3 parts per minute. After the addition is complete, continue stirring for an additional lj minutes to hydroxylate)
Adjust the pH to g,o~9.0 with an aqueous solution of lium.

On the other hand, water containing hydroxide) IJumuda, j part
Hydrogenated rosin (Harima Kasei Kogyo Co., Ltd., Harimatsu X) in 0 parts, 7.7. A clear rosin soap solution containing part j is prepared and added to the silica coated pigment slurry. After stirring for about /j minutes, water/θθ part and calcium chloride/7
The rosinate salt is precipitated by adding 4 parts of an aqueous solution over 1S minutes. This product was washed with water and filtered using a conventional method.

The mixture was dried and ground to obtain a calcium rosin soap-treated silica-coated lead chromate pigment composition.

Performance tests of the Example products and Comparative Example products obtained as described above were evaluated in the following manner, and the results are shown in Table-2.

l Heat resistance (/-/) test and preparation of test pieces High-density polyethylene resin [Mitsui Petrochemical Industries, Ltd. &
! , Hi-Zex λ100J'J! A mixture of 00 parts and sample Jj part was mixed with an extruder [JQ m/mφ extruder manufactured by Thermo Plastics Industries Co., Ltd.]/4.
Prepare color chips for testing at 3°C. Next, this color chip was heated to a temperature of 200°C using a screw injection molding machine [8jl-JO-A type, manufactured by Yamaguchi Seiki Co., Ltd.].
Standard test panels are made by injection molding using a cycle time of 2 seconds.

Test panels were prepared in the same manner as for standard springs, except that the samples were allowed to stay at each temperature of 2Fθ°C and 32Oυ for 3 minutes.

(l-2) Evaluation method Each test piece of molded panel obtained at one temperature each of molding temperature -OOoo, -10℃ and 30℃ is visually and color difference meter molded panel at temperature -00℃ is standard. The change in hue is determined by comparing it with this. The results are expressed using the scoring system ζζ, with "IO" indicating no color change and r/J indicating complete discoloration.

2. Preparation of Light Resistance (J-/) Test Piece 2.0 parts of the sample and castor oil/D part were placed under a load of t using a two-bar set muller (manufactured by Tester Sangyo Co., Ltd.).7. jkg (
knead once at 100 rpm to form a uniform paste.

This pasteco, J part and melamine alkyd resin (NOF @), Nilasan Melami TK/.

U-shaped clear]6. Mix well with Part Q to form a paint.

Next, apply it evenly to aluminum foil with a 6 mil applicator and leave it for 60 minutes.

1. Baking treatment was performed for 60 minutes in a hot air constant temperature dryer set at 30°C to create a test piece.

(Coco) Test and Evaluation Method Co., Ltd., FA-λ type, light source: carbon arc lamp] for SOO time exposure.

For this exposed test piece, the change in hue was determined visually and with a color difference meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., ND-zoIIDw type), and those with no change in one color were designated as "IO", and those with no change in one color were evaluated as "IO". It is expressed in a scoring system with "l" indicating discolored.

Dust scattering rate 100 parts of sample powder was taken into a 300 td beaker, a Gakken dust measuring device was set at a height of 13 dragons above the beaker, and a magnetic stirrer with a length of 1IO1111 and a diameter of 7 degrees was used. Stir the sample at a rate of 60 revolutions per minute using a tick stirrer. The dust measuring device measures 301 particles per minute.
By suctioning for 3 minutes at an air volume of The weight of the attached dust was measured, and the rate was expressed as a percentage as the dust generation rate.

Preparation of Acid Resistance (Glue) Test Piece A test piece is prepared in the same manner as the test piece used for the light resistance test, except that the aluminum foil is replaced with a glass plate.

(Darko) Test and Evaluation Method Each test piece was immersed in concentrated hydrochloric acid (1N) at 0°C for 13 minutes. The change in hue of the test piece subjected to the immersion test was determined visually and with a color difference meter.

It is expressed in a scoring system with "IO" indicating no color change and "r/J" indicating complete discoloration.

From the above facts, it is recognized that the performance improvement of the pigment composition according to the present invention is remarkable.

〔Effect of the invention〕

The modified silica-coated lead chromate pigment composition of the present invention is surface-treated with an organosilicon compound, but has lower friction resistance than conventional silica-coated lead chromate pigments or rosin-treated products thereof. It has excellent properties and improves pigment resistance overall. -Also, this is an unexpected and interesting effect.

The effect of preventing the product powder from scattering has been significantly improved, and it can be said that it has great practicality. This superior action and effect is probably due to
This is understood to be due to the reaction between the silica film and the organosilicon compound, which imparts a tighter silica film to the pigment particles, or the formation of an organosilicon polymer, thereby forming a more stable film on the silica film. Ru.

Claims (1)

[Scope of Claims] 1. A silica-coated lead chromate pigment having at least a substantially continuous amorphous silica film formed on the surface of the lead chromate pigment particles is surface-treated with an organosilicon compound. A modified silica-coated lead chromate pigment composition characterized by: 2. Lead chromate pigments are CI-77600 and CI-776.
The modified silica-coated pigment composition according to claim 1, wherein the modified silica-coated pigment composition is one or more selected from the group consisting of lead chromate pigments such as No. 01, CI-77603, and CI-77605. 3. The lead chromate pigment is described in claim 1 or 2, in which one or more hydrous oxides selected from magnesium, cerium, aluminum, titanium, zirconium, or antimony are deposited. A modified silica-coated lead chromate pigment composition. 4. The modified silica-coated lead chromate pigment composition according to claim 1, wherein the organosilicon compound is a silane coupling agent. 5. The modified silica-coated lead chromate pigment composition according to claim 1, wherein the organosilicon compound is a modified or unmodified silicone oil. 6. A patent consisting of 0 to 5% metal hydrated oxide (calculated as anhydride), 5 to 30% amorphous silica as SIO_2, and 1 to 40% organosilicon compound based on the total weight of lead chromate pigment. A modified silica-coated lead chromate pigment composition according to claim 1. 7. Modified silica coating characterized by adding an organosilicon compound to a silica-coated lead chromate pigment, mixing uniformly in the presence or absence of water or an organic solvent and heating, or heating and drying after mixing. A method for producing a lead chromate pigment composition. 8. A method for producing a modified silica-coated lead chromate pigment composition according to claim 7, wherein the mixing is carried out using a Henschel mixer.