JPS599582B2 - Water-dispersible metal pigment composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to water-dispersible metal pigment compositions.

In recent years, air pollution caused by organic solvents has become a major problem, and the paint industry is increasingly using water-based paints that do not use organic solvents. One type of water-based paint is a water-based paint that uses a scaly metal pigment. The flaky metal pigments used in this water-based paint are dry ground using a grinding aid consisting of a saturated or unsaturated fatty acid such as stearic acid or oleic acid, or a derivative thereof, or in the presence of a hydrocarbon-based organic solvent. So-called wet crushing,
A composition made water-dispersible by adding a surfactant to this is used as a water-dispersible metal pigment composition. The surfactants conventionally used in this water-dispersible metal pigment composition include alkanolamide, polyoxyethylenediamine, and oxazoline. However, water-based paints containing this water-dispersible metal pigment composition have a disadvantage in that they have low storage stability.

For example, there are disadvantages such as poor dispersibility of the metal pigment itself, generation of a large amount of gas, increased viscosity, and changes in the color tone of the coating film obtained from this paint. The object of the present invention is to solve the above-mentioned difficulties of conventional water-dispersible metal pigment compositions, that is, to provide a water-dispersible metal pigment composition that can produce a water-based paint having excellent storage stability.

This object of the present invention is to provide a water-dispersible metal pigment composition containing a scale-like metal pigment and a surfactant, in which a sorbitan fatty acid ester (hereinafter referred to as surface It is called activator A.

) and polyoxyethylene sorbitan fatty acid ester (hereinafter referred to as surfactant B) having an oil-in-water type tendency, and the blending ratio of both is that of surfactant A.
/Surfactant B 2 to IN' is used, and in this case, as an organic solvent, in particular a boiling point 6 having a hydrophilic group is used.
This is achieved by using an organic solvent at 0-200°C. According to the research of the present inventor, two specific types of surfactants, surfactant A and surfactant B, are selected from various surfactants, and these specific surfactants are When the two methods of using a specific organic solvent having a boiling point of 60 to 200°C having a hydrophilic group are used in combination, dispersion of a water-dispersible metal pigment composition in an aqueous paint is necessary. A new fact has been discovered that the properties of the paints are significantly improved, and the storage problems of water-based paints using conventional water-dispersible metal pigment compositions are eliminated as much as possible.

In addition, when a fluorine-based surfactant is contained in the water-dispersible metal pigment composition, when a water-based paint containing the water-dispersible metal pigment composition is applied, metals in the coating film may be reduced. A new fact was also discovered that color unevenness caused by pigment flow is improved and the metallic feel of the coating film is further improved. The present invention has been completed based on these new facts. As the flaky metal pigment used in the present invention, any of the various conventionally known pigments can be used effectively as they are.

More specifically, powders of aluminum, copper, and their alloys are mixed with mineral oil such as mineral spirits, or
Alternatively, it may be mixed with higher fatty acids or derivatives thereof without being present, and then ground. Examples of higher fatty acids in this case include stearic acid, oleic acid,
Examples of saturated or unsaturated fatty acids such as palmitic acid and myristic acid, and derivatives thereof include amines, amides, and salts thereof, and these fatty acids or derivatives thereof are usually used in an amount of 0.5 parts by weight per 100 parts by weight of metal powder. ~5 parts by weight is used. As the mineral oil, mineral spirits, trol, xylol, solvent naphtha, etc. are usually used in a proportion of 35% by weight or less. The surfactant A used in the present invention usually has the following structural formula.

[However, R represents an alkyl group having 12 to 18 carbon atoms, and R' represents a hydrogen atom or an RCO group.] Typical examples include zorbitan monolaurate, zorbitan monopalmitate, zorbitan mono Stearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate and the like can be mentioned.

Further, as the surfactant B, one represented by the following structural formula is used. [However, R represents an alkyl group having 12 to 18 carbon atoms, and 1, m, and n each represent an integer of 0 to 15.

However, 2+m+n=1 to 45] None of these surfactants A and B have ever been used in a water-dispersible metal pigment composition of this kind, and even less these surfactants A and B. There is also nothing known about using them together.

In the present invention, the mixture of surfactants A and B is 0.2 to 17% by weight based on the metal content of the water-dispersible metal pigment.
It is preferably used in a range of 3 to 7% by weight. In this case, if the amount does not reach 0.2% by weight, the desired effect cannot be achieved, and if it exceeds 17% by weight, the coating obtained when applying the water-based paint obtained by blending the composition. A disadvantage arises in that the water resistance of the membrane is reduced. Further, surfactants A and B need to be used together in a ratio of A/B=I to 16A. At this time, if the ratio does not reach %, higher fatty acids or their derivatives adsorbed on the surface of the water-dispersible metal pigment tend to be peeled off, and conversely, if the ratio exceeds 16A, the water-dispersible metal pigment Dispersion stability in water-based paints tends to decrease. These surfactants A. The preferred blending ratio with 15B is ~Z''. In the present invention, it is necessary to use an organic solvent having a hydrophilic group and a boiling point of 60 to 200°C. In this case, if a material whose boiling point does not reach 60°C is used, the stability of the water-dispersible metal pigment composition in the aqueous paint tends to decrease;
If it is higher than this, the metal pigment tends to run down and color unevenness occurs in the coating film obtained from the aqueous paint containing the composition, which is not desirable. Having hydrophilic groups such as these,
Specific examples of organic solvents having a boiling point of 60 to 200°C include n-amyl alcohol, diacetone alcohol, I
sO-propyl alcohol, n-butyl alcohol, I
Examples include sO-butyl alcohol, ethylene glycol, ethylene glycol monoalkyl ether, diethylene glycol, diethylene glycol monoalkyl ether, and the like. These organic solvents may be used alone or in combination of two or more. Other additives such as various known coloring pigments, antifoaming agents, etc. other than metal pigments may be added to the water-dispersible metal pigment composition of the present invention as required. There are no particular restrictions on the means for preparing the composition of the present invention, and a wide variety of methods can be used, and the order in which the components are mixed is also not restricted. In the present invention,
A fluorine-based surfactant is added to the water-dispersible metal pigment composition in an amount ranging from 0.0025 to 0.0025% based on the metal content of the metal pigment in the composition.
10 weight? Preferably, by making them coexist in a proportion of 0.005 to 3.0% by weight, the flaky metal pigment can be arranged in parallel to the coating surface in the coating film, thereby preventing color unevenness and preventing the metallic pigment from forming a metallic pigment. It can significantly improve the feeling.

However, this fluorine-based surfactant does not impair the above-mentioned excellent properties of the water-dispersible metal pigment. At this time, if the amount of the fluorine-based surfactant used does not reach 0.0025% by weight, the effect of the addition of the fluorine-based surfactant will not be fully exhibited;
When the amount exceeds 0% by weight, the water resistance of the coating film obtained from the water-based paint containing the composition tends to decrease. In the present invention, the fluorine-based surfactant used has the following structure. (1) Rf(CH2)l
'COO(CH2CH2O)m'H [However, l' is 0 to 3
, m' is an integer of 1 to 20, and Rf is a carbon number of 1 to 18
represents a perfluoroalkyl group] (2) Rf(C
H2) l'SO2NRCm'H2m'PO(0R)2[
However, Rf, l', m' represent the same as above, and R' represents hydrogen or a lower alkyl group]17'
-1J ~ 7-14' l ▼ - C [However, A is (CH2CH2O)m'H or 0Na is Rf,
l' and m' each represent the same as above] [However, B represents SQ2, CO or CH2CO, X represents 0Na, 0K or 0NH4, and Rf and l' represent the same as above.

] [However, Rf, l', ml are the same as above] Veb-7
u1 [However, Rf and m' are the same as above] [However, Rf, R/ and m' are the same as above] There is no particular restriction on the timing of adding these fluorine-based surfactants.

Experimental examples are shown below to make the features of the present invention more clear.

Experimental Example 1 Five types of non-leafing water-dispersible metal pigment compositions were used as samples, and the samples were added to water-based paints to measure their storage stability.

However, the sample used in this example was prepared as follows. That is, non-leafing type aluminum paste (
``Alpaste 1100MA7, non-volatile content 80% by weight,
4369 (manufactured by Toyo Aluminum Co., Ltd.), a mixture of 66.59 butyl cellosolve and 24.59 of a specific surfactant shown in Table 1 below was added and thoroughly mixed. These results are shown in Figures 1-2 and Tables 2-3.
However, Figure 1 shows the dispersion stability of aluminum pigments in water-based paints, and Figure 2 shows the results of measuring the amount of hydrogen gas generated over time in water-based paints. Furthermore, Tables 2 and 3 show the results of measuring the color stability and viscosity change, which indicate the storage stability of the paint. However, the above values indicate the color difference between a sample coated with a water-based paint immediately after preparation and a sample coated with a paint left at 50°C for 30 days.

The above values represent viscosity (unit: Cps). However, the methods for measuring the physical properties shown in Figures 1 to 2 and Tables 2 to 3 are as follows.

Dispersion stability for binder resin> Melamine-alkyd resin (solid content 42%, pH 8.5
) Add sample 37.59 directly to 500g and mix well to disperse. Take 100d from this dispersion, put it into a 100ml graduated cylinder, and leave it to stand still until the aluminum pigment is dispersed. The volume change of the layer with time was measured.

It shows that the smaller the decrease in the dispersion volume over time, the better the dispersion stability. Amount of hydrogen gas generated from the paint> 1009 in the paint prepared above was separated into a glass pin, a vent pipe was attached, and the amount of reaction gas (hydrogen gas) generated at 50°C was measured. Compared to Fu6.

Fu 4 and Fu 5 were not measured because of their poor dispersibility. Color stability and viscosity change in water-based paints〉Specifically, using an E-type viscometer, the paints prepared above were measured immediately after blending and after the hydrogen gas generation test in water-based paints. While measuring the viscosity, it was coated on a degreased aluminum plate using a doctor blade with a gap of 0.1 m/m, and heated at 120°C x 30°C.
The color difference (ΔE) of the separately baked coating film was measured using a color difference meter manufactured by Nippon Denshoku Co., Ltd. A similar test was performed on melamine
Acrylic water-based binder resin (solid content 32%, PH8.
5) A sample prepared by dispersing 7.5 parts of the sample in 100 parts was also tested. Experimental Example 2 Samples were prepared in the same manner as in Experiment 1, except that the prescribed and prescribed amounts of surfactants shown in Table 4 below were used.

Regarding this sample, the dispersion stability of the aluminum pigment in the water-based paint was measured in the same manner as in Experimental Example 1 above. The results are shown in Table 4 below. Experimental Example 3 A predetermined amount of the fluorine-based surfactant shown in Table 5 was added to Sample Return 1, and the mixture was thoroughly stirred and mixed to prepare a sample of a water-dispersible aluminum pigment composition.

Melamine-acrylic resin (PH8.5, solid content 32%)
Sample 7.59 was directly added to 1009 and thoroughly mixed and dispersed to prepare a paint. This was applied and dried on a steel plate to a dry film thickness of 47 μm, and the orientation of the metal pigment in the film was measured. The results are shown in Table 6. However, the degree of inclination of the above particles was measured as follows. Cut the coating film with a sharp knife, scan the cut surface over a width of 1m1t with an electron microscope, count the number of particles that are tilted to the surface to be coated every 10 degrees, and calculate the number of particles in relation to the total number of particles measured. It is expressed as

However, in Table 6, the smaller the inclination angle, that is, the greater the degree of distribution of aluminum particles parallel to the surface to be coated, the more the color unevenness is prevented and the metallic feel becomes greater.

Experimental example 4 Leafing type aluminum paste ("Alpesto 1")
00SR'', non-volatile content 80% by weight, manufactured by Toyo Aluminum Co., Ltd.), and in the same manner as in Experimental Example 2.
The samples shown in the table were prepared, and the dispersion stability, amount of hydrogen gas generated, and viscosity change were measured using the same methods.

The results are shown in Table 7. Experimental Example 5 Commercially available non-leafed brass (“BS-606” manufactured by Wolstenholme, UK) 1 crushed by the stamping method
009, 7 g of a mixture of sorbitan monostearate and sorbitan monolaurate in a ratio of 2:4 (weight ratio) and 15.49 ethylene glycol were mixed, and the sample was prepared in the same manner as in Experimental Example 2. At the same time as preparation, dispersion stability, hydrogen gas generation amount, and viscosity change were measured using the same method.

The results were extremely satisfactory in all respects.

[Brief explanation of drawings]

FIG. 1 is a graph showing the dispersion stability of metal pigments in water-based paints containing the water-dispersible metal pigment composition of the present invention over time.

Claims (1)

[Scope of Claims] 1. A water-dispersible metal pigment composition comprising a scaly metal pigment, a surfactant, and an organic solvent having a boiling point of 60 to 200°C and having a hydrophilic group, wherein the surfactant is It is contained in a ratio of 0.2 to 17% by weight based on the metal content of the metal pigment, and the surfactant is a mixture of sorbitan fatty acid ester and polyoxyethylene sorbitan fatty acid ester, and the ratio of the two is former/latter = 1/4~16
A water-dispersible metal pigment composition characterized in that: /4. 2. The water-dispersible metal pigment composition of the first claim has a content of 0 with respect to the metal content of the metal pigment in the metal pigment composition.
．． 0025-10% by weight of a fluorine-based surfactant is contained in a water-dispersible metal pigment composition.