JPS6018750B2 - Improvement of zinc phosphate film chemical conversion treatment solution - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in zinc phosphate coating chemical conversion treatment solutions.

More specifically, the present invention relates to a treatment solution that can form a zinc phosphate film having excellent properties on the surfaces of various metals such as iron, steel, zinc, and zinc alloys, and can also form the film with good workability. In order to improve the corrosion resistance and paint adhesion of the above-mentioned metals, it is widely and generally practiced to chemically form a phosphate film on the surface of the metal as a pre-painting treatment.

Recently, however, various improvements have been made to this type of chemical conversion treatment liquid in order to mass produce high quality products. In particular, in the case of so-called pre-coated products, in which a phosphate film is chemically formed on a coiled metal material, this is then painted, and the metal material is then molded, the bending workability of the chemical conversion film, etc. Particular emphasis is placed on paint adhesion. In addition, in the surface treatment process for pre-coated products, metal materials are generally held and conveyed by rolls, and in particular are bent and held by accumulators, so the chemical conversion coating is easily peeled off and powdered (powder flaking), and this remains attached to the metal. When materials are subjected to coating, the coating atmosphere is often contaminated, resulting in coating defects. From this point of view as well, the chemical conversion coating is required to have good bendability. In addition, in general phosphate film chemical conversion treatment, sludge is unavoidably generated during treatment, and its treatment (e.g., cleaning inside the treatment liquid tank, sludge disposal) is complicated. If sludge sticks to the surface of the heating means in the tank, it will reduce its thermal efficiency, and on the other hand, in the case of the treatment liquid in the pipes in the external heating method, the pipes are likely to be clogged due to the sludge sticking, so it is necessary to clean the sludge frequently. be.

By the way, when we specifically examine the improved millet that has been proposed to date, it is first proposed to add a phosphate ester of starch or its acid decomposition product to a general phosphate film chemical conversion treatment solution. (Special Publications No. 46-17047, No. 54-24973, No. 57-723)
(See No. 2).

According to this, the crystals of the phosphate film become finer and more delicate,
It is said that the weight of the coating is reduced and the adhesion of the coating to the surface metal is increased, resulting in improved coating adhesion and corrosion resistance after painting. Furthermore, it is said that a reduction in the amount of sludge generated can be achieved. However, it has been found that the crystals of the phosphate film produced by this technique are needle-shaped and easily disintegrate during bending. Therefore, the bendability of the chemical conversion coating on pre-coated products is still insufficient, and as mentioned above, there is a risk that the chemical conversion coating will flake during the surface treatment process of pre-coated products, leading to coating defects. Next, it has been proposed to add a reaction product of aminoalcohol and phosphoric acid (see JP-A-52-43737).

According to this, it is possible to provide a phosphate film in which the crystals are dense and do not contain needle-shaped crystals, and the amount of sludge generated can be reduced, and the quality of the sludge can be controlled so that the sludge does not stick to the heating means, etc. It is said that it is possible. However, according to the technology, the bendability of the phosphate film is not yet satisfactory, and even if the amount of sludge generated can be reduced, the degree of improvement is still low. There is room for Next, it has been proposed to add a phosphoric acid surfactant (see Tokusekki No. 50-143736).

According to this, it is said that the rate of sludge formation can be reduced, but the phosphate film has insufficient bendability and also has the problem that the treatment liquid foams during use. ing. As described above, the conventional technology has a problem in that it is not possible to simultaneously satisfy the bending processability of the phosphate film and the reduction of sludge generation during chemical conversion treatment.

Therefore, an object of the present invention is to improve the adhesion between the crystals of the chemical conversion coating and the base metal, and to reduce the collapse of the crystals during bending, thereby improving the paint adhesion of metal materials that undergo bending. It is an object of the present invention to provide a zinc phosphate film chemical conversion treatment solution that can be improved.

Another purpose is to provide a chemical conversion treatment solution that can reduce dusting of chemical conversion coatings due to bending and holding of metal materials during the surface treatment process, thereby reducing contamination of the coating atmosphere and preventing the occurrence of coating defects. There is something to do. Still another object is to provide a treatment liquid that can reduce the amount of sludge generated during chemical conversion treatment and can prevent sludge from sticking to heating means and the like. For this purpose, in a treatment solution for chemically forming a zinc phosphate film on a metal surface, 'a' - a phosphoric acid esterified product of starch or its decomposition product, and {b' aliphatic C,-9 amino alcohol and phosphoric acid or Reaction product b-1 with condensed phosphoric acid or a salt thereof,
A reaction product b-1 of aliphatic C2-6 polyhydric alcohol and phosphoric acid or condensed phosphoric acid or a salt thereof, and a poly(3-1
This is achieved by a zinc phosphate film chemical conversion treatment solution characterized by adding at least one phosphate ester of alkylene oxide C2-3 adduct (b-3).

The phosphoric acid esterified product of starch or its decomposition product, which is the component {a', used in the present invention may be one that is known per se. For example, starch or its decomposed product (e.g., dextrin, maltose, glucose) is Alternatively, those obtained by esterification using sodium phosphate according to a conventional method (for example, culturing at 120 to 190 qo under reduced pressure or normal pressure) can be used.

Further, it is also possible to use a product obtained by decomposing the phosphoric acid ester of starch obtained in this way with an acid (eg, phosphoric acid, hydrochloric acid) according to a conventional method. Incidentally, such phosphoric acid esterified products can be used either singly or in a mixed state of two or more kinds, but the total content of bound phosphorus is 0.5 to 2.5% by weight, preferably 1.2% by weight. ~1.
It is particularly advantageous to contain % by weight of males in terms of improving coating adhesion. A specific example of this phosphate ester 'a' is "Hyrate FN" manufactured by Nichirin Chemical Co., Ltd.
(1.4% by weight of bound phosphorus), "Cifix PI120" (2.% by weight of bound phosphorus), "Cifix PI129" (0. box weight% of bound phosphorus), "Scifix PI18" (0. 6% by weight), “
Scifix P18” (0.8% by weight of bound phosphorus), “
"Syfix P12" (bound phosphorus 0.0% by weight), Nippon Star Chemical "Buribain" (bound phosphorus 1-1.5% by weight),
"Gelastar BP-3" (0.3% by weight of bound phosphorus), "
Vetrocoat UJ2200” (bound phosphorus 0.3% by weight)
(dextrinization), “Dexel UJ”, “Gumtex” (dextrinization), “British Gum 75”
(dextrinization), “Hoster SI” manufactured by Matsutani Chemical Industry Co., Ltd.
Examples include "OO" and "Hoster D-13".

This phosphate ester compound (a and others) may be added at a ratio of 100 to 500 blood, preferably 500 to 350 blood, in the total amount of the chemical conversion treatment solution.

If the amount added is too small, the effect of adding the phosphate ester compound (particularly improving paint adhesion in new song processing) cannot be expected, while if it is excessive, the effect corresponding to the amount added cannot be expected. The viscosity of the processing liquid increases, resulting in poor workability. Component 'b} used in the present invention is a reaction product (b-1) of aliphatic C,-9 amino alcohol and phosphoric acid or condensed phosphoric acid or a salt thereof, aliphatic C2-6 polyhydric alcohol and Reaction product b-2 with phosphoric acid or condensed phosphoric acid or a salt thereof, and phosphoric acid ester of poly(3-15 mol) alkylene oxide C2-3 adduct of higher alcohol or alkylphenol b-3
are mentioned, and at least one of them may be used.

Specifically, the amino alcohol in the above component b-1 includes monoethanolamine, jetanolamine,
Examples include oxydiethanolamine, dipropanolamine, triethanolamine, and tripropanolamine.

Examples of salts of phosphoric acid and condensed phosphoric acid include alkali metal salts (eg, Na salt), ammonium salts, and amine salts (eg, trietanoamine salt, triethylamine salt). Component b-1 is, for example, the above-mentioned Hakama Kaisho 52-43737.
It can be obtained by heating the above-mentioned amino alcohol component and phosphoric acid component in a mixed state as disclosed in No.

The reaction time must be maintained at 180 qo for at least 3 whiskers, and the reaction temperature is at least 170 qo, preferably at least 18 qo. In addition, in the present invention, in addition to carrying out the heating reaction at 18 psi for 1 hour as disclosed in the above-mentioned Samurai Batsu No. 52-43737, (i) the heating time is 180 psi.
oo for 1.5 hours or more, preferably 2 hours or more,
(ii) Component b-1 obtained by increasing the reaction by maintaining the heating temperature at 190 °C or higher for 1 hour, or by maintaining the heating temperature at 180 °C for 1 hour under reduced pressure in a dish, or a combination thereof. It has been found that the same effect can be achieved even if the amount added is halved.

The reason is that Example 1 of the above-mentioned Japanese Patent Application Laid-Open No. 52-43737
The liquid chromatogram of the reaction product obtained by the method of the present invention is as shown in FIG. 1, while the liquid chromatogram shown in FIGS. The product obtained by the method is characterized by strong peaks of ■ and ■, but in the method of the present invention, the peaks of ■ and ■ disappear and the peaks of ■ and ■ become stronger, and when the reaction proceeds further, the peaks of ■ and This is because only a peak was observed, and from this it can be inferred that the reaction products of both methods are different. The active ingredient of component b-1 is considered to be a phosphate ester, but it may be a fully esterified product, a partially esterified product, or a mixture thereof.

In addition, component b-1 may be used in a state containing a derivative (mainly considered to be an amino alcohol component salt of a phosphoric acid component). Specific examples of the polyhydric alcohol in component b-2 above include ethylene glycol, propylene glycol, 1,3-butanediol, 4-ethoxy-2,3-butanediol, and glycerin.

As salts of phosphoric acid and condensed phosphoric acid, the above component b-1
You can use the same salt as in . This component b-2 can be obtained by heating the above-mentioned polyhydric alcohol component and phosphoric acid component in a mixed state to a temperature of 150 to 19,000 under reduced pressure or normal pressure. The reaction product is considered to be a phosphate ester, but it may also be a fully or partially esterified product or a mixture thereof. As a specific example,
Examples include ethylene glycol acid phosphate ("EGAP" manufactured by Johoku Kagaku Co., Ltd.), sodium glycerophosphate, and triethanolamine salt of ethylene glycol acid phosphate. Component b-3 is an alkyl phosphate ester type surfactant modified with ethylene oxide or propylene oxide, and specifically includes the following. (i) Mixtures of ethoxylated/nilphenol or octylphenol monoesterates and gesters containing 3 to 15 moles of ethylene oxide.

For example, the phosphate ester of nonylphenol ethoxylated with 6 moles of ethylene oxide, the phosphate ester of nonylphenol ethoxylated with 10 moles of ethylene oxide.

As a commercially available product, “Gafatsuku RE-610” manufactured by GAF
``Seranol PS-17'' manufactured by Lone Progil,
``EMCO'S-141'' manufactured by Witco Chemical Company. (
ii) Higher alcohol alkylene oxide adduct phosphate ester o■ Phosphate ester of ethoxylated tridecyl alcohol, for example phosphate ester of tridecyl alcohol ethoxylated with 8 mol of ethylene oxide.

As a commercially available product, “Seranol PA” manufactured by Lone Pro Gil
-21 HASOSCHETE PROTEX Co., Ltd. "Phosphack DI Shuyama Other Linear C with 6 moles of propylene oxide,
Phosphate ester of o-,2 alcohol, phosphate ester of oxotridecyl alcohol ethoxylated with 4 moles of ethylene oxide.

■ C, . with 6 ethylene oxide groups. A mixture of mono-esterification products and gestation products of oxoalcohols having an alkyl group of -, 3, such as a phosphate ester of oxotridecyl alcohol ethoxylated with 6 moles of ethylene oxide.

This component b-3 may be a fully esterified product or a partially esterified product or a mixture thereof, or a salt thereof (
For example, Na salt, triethylamine salt, triethylamine salt) can also be used.

In the present invention, as the component b, one or more of b-1, b-2 and b-3 is added to the total amount of the chemical conversion treatment solution.
What is necessary is just to add it so that it may become a ratio of 00 to 500 & wind.
If the amount added is too small, the crystals of the chemical conversion coating will not become granular.
Crystal collapse is not reduced, the adhesion of the crystals is poor, and the bending and unbinding properties after coating are poor. Furthermore, the amount of sludge generated is not reduced. On the other hand, if it is in excess, film adhesion during chemical formation will be inhibited, and in the case of component b-3, foaming of the treatment liquid will increase. The zinc phosphate film chemical conversion treatment solution to which the above-mentioned components a and b are added may be any ordinary one, and its standard formulation is as follows.

Zn ion 700-180 Hard Ni ion 500-200
Urigo N03 ion 400~1
20 hard P04 ions 7000
~1200 wind SiF6 ions
Wind total acidity of 300-100* 10-
25 points free acidity* 0.5-2.
0 point acid ratio* 6-2
0*Total acidity is the amount of 0.1N NaOH required until the solution turns pink with 0.1N NaOH using phenolphthalein as an indicator.

*Free acidity is determined by taking the treatment solution at a concentration of 10% and fromphenol blue. The amount of 0.1N NaOH required until the liquid turned green to blue using 0.1N NaOH as an indicator. *Metal materials to be chemically treated with the treatment solution of the present invention, which has an acid ratio of total acidity/free acidity or higher, include, for example, steel sheets, heat-dipped galvanized steel sheets, electrolytic galvanized steel sheets, and heat-alloyed steel sheets. Examples include bonded galvanized steel sheets and alloy electrogalvanized steel sheets.

The treatment of such a metal material with the chemical conversion treatment solution of the present invention may be carried out by a method known per se. for example,
The metal material is brought into contact with a titanium phosphate-based surface conditioning solution for a few seconds, and after being fixed with a roll, it is soaked or sprayed in a treatment solution heated to about 60 to 75 minutes for 3 to 20 minutes.
The product may be brought into contact with the product for a few seconds, rolled, and then brought into contact with an aqueous solution of a chromic acid-based post-treatment agent (warmed to about 65 qo) for several seconds by soaking or spraying, and dried with a roll. Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

The standard formulation of the zinc phosphate film chemical conversion treatment solution used in these examples is as follows.

Zn ion 10 squares N
i-ion 140 four N
03 Aeon 90Q Tough P
04 AEON 750 cucumber S
iF6 ion Iso O style total acidity 150 points free acidity
1.9 point acid ratio
80 Example 1 '11 Components a and b are added in the indicated amounts as shown in Table 1 to the above-mentioned standard formulation treatment solution, and the mixture is subjected to chemical conversion treatment.

t2} The metal material used is a heat soaked galvanized steel plate (minimized spangle ten skin pass) with a thickness of 0.35. '3} The above metal material was first coated with a titanium phosphate surface conditioner ("Fixodine 5J 0" manufactured by Nippon Paint Co., Ltd.).
．． After soaking in a 3% by weight aqueous solution at 25oo for 2 seconds, roll-rolling, soaking in a chemical conversion treatment solution for 5 seconds at 660-roll-rolling twice, washing with clean water, and then using a chromic acid treatment agent (Nippon Paint). 0 of “Deoxylite 41” manufactured by
．． It is immersed in a box weight % aqueous solution at 65°C for 2 seconds, then dried on a roll without washing with water.

'4 - Apply the above chemically treated metal material to an epoxy primer (Nippon Paint Co., Ltd.'s "Superlac DIFPOI").
It was bar coated with Primer J and baked to a final board temperature of 190°C (dry coating coverage: 5 coats/final).

Next, apply an oil-free polyester top coat (“Superlac DIFF 80 No. 23” manufactured by Nippon Paint Co., Ltd.).
Blue) was applied to the surface until the board temperature reached 20030 (Top coat dry coating amount 15 days/final). '
51 Table 1 shows the results of various performance tests on the chemically treated boards and painted boards obtained in this way.

In addition, the results of sludge generation tests in chemical conversion treatment liquids are also the first.
Shown in the table. In addition, this example, the following comparative example, and Example 2-2
The reaction product b-1 of amino alcohol and phosphoric acid used in steps 6 to 6 was produced by the method disclosed in the examples of JP-A-52-43737.

That is, both mixtures were held at 180 oo for 1 hour. Ship/Ear Comparative Example 1 The same procedure as in Example 1 was carried out except that the indicated amount of component a or b shown in Table 2 was added to the above-mentioned standard formulation treatment liquid.

The results are shown in Table 2. Table 2 Example 2 Example 2 was carried out in the same manner as in Example 1, except that components a and b shown in Table 3 were added in the indicated amounts to the treatment liquid of the above standard formulation.

The results are shown in Table 3. The amino alcohol and phosphoric acid reaction product b-1 used in Examples 7 and 8 was produced by holding a mixture of both under reduced pressure (0.8 atm) at 180 pm for 2 hours. The liquid chromatogram was similar to that shown in FIG.

ship snake The various test methods are as follows.

'1} Reference photo of crystal form of chemical conversion coating: Scanning electron micrograph (magnification 75) ■ Bending processability test of chemical conversion coating: 'a} 2 bending test: Round grains with two diameters are placed on a chemical conversion coating. After folding it 18 times, the outer surface of the folded portion is observed using a scanning electron microscope.

○: Almost no crystal collapse.

△: The crystal has collapsed to an intermediate degree between ○ and ×.

×: The crystal has almost completely collapsed. {b} Bent part cloth cost test: The bent part of the chemical conversion treated board according to 'a} above is rubbed several times with a cloth and then observed with a scanning electron microscope.

○: Almost all crystals remain Δ: Crystals remain to an extent intermediate between ○ and ×.

×: Almost no crystals remain. '31 Paint adhesion test: 'a} OTT test: Painted board was heated in a constant temperature room at 20°C for 18 days.
After 0° bending and pressure bonding with a force, an adhesive tape is attached to the bent part, and when the adhesive tape is peeled off, the state of peeling of the coating film on the new bent part is observed.

'b} T test: Two coated plates of the same thickness are sandwiched in a constant temperature room at 20qo, bent at 180o, crimped with a force, and then carried out in the same manner as in [a} above.

5 points: No peeling of the coating film is observed.

4.5 points: Peeling of the paint film is observed in an area of less than 5%.

4 points: Peeling of the paint film with an area of 5 to less than 1 inch is observed 3.
5 points: 3 where paint film peeling of less than 10-20% area is observed
Point: Peeling of the paint film in an area of 20 to less than 50% is observed 2
Point: 50 to 80% area peeling of paint film is observed 1
Point: Peeling of paint film is observed in 80-100% area [c
} Coin scratch test: Hold a coin against the painted surface and pull it with enough force to observe the extent of scratches.

5 points: There is only a small scratch at first, but then the coin slides on the painted surface. 4 points: About 10 to 30% of the stuck area peels off at the interface between the chemical conversion film and the primer layer. 3 points: It sticks. Two points where about half of the part peels off at the interface between the chemical conversion film and the primer layer: One point where about half to 90% of the stuck part peels off at the interface between the chemical conversion film and the primer layer: More than 90% of the stuck part peels off at the interface between the chemical conversion film and the primer layer [41 Sludge generation test 'a' Heating test: Put 400% of the chemical conversion treatment liquid into a beaker and heat it with a 300W technical heater (voltage 100V)
).

After maintaining the temperature at 70±5°C for 20 minutes while shaking, the amount of sludge generated (the total amount of sludge that adhered to the heater and that that settled in the beaker) was measured.

'b} K value: Since this K value is generally employed as one measure of evaluation of sludge generation during chemical conversion treatment, the K value under the chemical conversion treatment conditions in Examples and Comparative Examples was calculated.

K value = Etching amount / Film amount Etching amount = (Weight of board before treatment - Weight of board after film removal) / Board area (T/R) Amount of film = (Weight of board after treatment - Weight of board after peeling) / Board area (1/2) To remove the chemical coating, use a solution in which 10 parts of ammonium dichromate is dissolved in 1 part of 28-30% aqueous ammonia, and after soaking the treated board in the solution for 5 minutes at room temperature. Adopt the method of wiping with a sponge.

〔supplementary explanation〕

The amount of zinc (△Zn) that can become sludge when a galvanized steel sheet is chemically treated is per unit area, △Zn=ZE
-ZC=Ew-Cw×0.428 Here, ZE is the amount of zinc eluted during the formation time per unit area of the galvanized steel sheet = Etching amount (Ew) (Ew/〆) Zc is the unit area of the galvanized steel sheet Amount of zinc in the film generated during per-conversion time = film amount (Cw) x (32/Zn3(P
○4) 2) (evening/de) = Cw x 0.428 {i) Conditions for not generating sludge: △Zn=0, so K value = Ew/Cw
=0.428(ii) Conditions for generating sludge: △Z
Since n>0, K value=Ew/Cw>0.428 Therefore, the larger the K value=Ew/Cw is compared to 0.428, the greater the amount of sludge generated.

[Brief explanation of drawings]

1 to 3 are liquid chromatograms of the additive components used in the present invention. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A treatment solution for chemically forming a zinc phosphate film on a metal surface, which comprises (a) a phosphate ester of starch or its decomposition product, and (b) an aliphatic C_1_-_
9 Reaction product b-1 of amino alcohol and phosphoric acid or condensed phosphoric acid or a salt thereof, aliphatic C_2_-
_6 Reaction product b-2 of polyhydric alcohol and phosphoric acid or condensed phosphoric acid or their salts, and poly(3 to 15 mol) of higher alcohol or alkylphenol
An improvement of a zinc phosphate film chemical conversion treatment solution, characterized in that at least one phosphate ester compound (b-3) of an alkylene oxide C_2_-_3 adduct is added. 2 The amount of each of component (a) and component (b) added is 100~
The treatment liquid of item 1 above, which has a concentration of 5000 ppm.