A flux for tinplate production and a tinplate surface treatment method

Abstract

The invention discloses a flux for tinplate production and a tinplate surface treatment method, wherein the flux for tinplate production comprises the following components: divalent stannate, aminosulfonic acid and salts thereof, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water; the concentration of the divalent stannate is 0.1-3 g / L in terms of divalent tin ions; the concentration of aminosulfonic acid and salts thereof is 0.5-5 g / L in terms of aminosulfonic acid ions; the concentration of the alkylphenol polyoxyethylene ether is 0.1-1 g / L; the concentration of benzylidene acetone is 0.1-1 g / L; the concentration of catechol is 0.5-3 g / L; and the concentration of the polyether is 0.05-0.5 g / L. The tinplate surface treatment method comprises the following steps: applying flux for tinplate production to the surface of the cleaned tinplate, and then performing soft melting, passivation and oiling treatments. The grain orientation of the tinplate layer is uniform, the grain arrangement of the alloy layer is dense and uniform, and the corrosion resistance is good.

Description

Technical Field

[0001] The invention relates to the field of tinplate production, and in particular to a flux for tinplate production and a tinplate surface treatment method. Background Art

[0002] The tin layer on the surface of tinplate is generally treated by soft melting, that is, the tinplate is heated to a certain temperature above the melting point of tin to melt the tin layer, and then quickly cooled by quenching water, the tin layer is recrystallized and a tin-iron alloy layer is formed at the interface of tin and iron, which can greatly improve the corrosion resistance and decorative effect of the tinplate. At present, the mainstream electroplating tinning process for tinplate production is the acid sulfate electroplating tinning process, and the tin plating solutions used are mainly phenolsulfonic acid (PSA) tin plating solution and methanesulfonic acid (MSA) tin plating solution; on the tinplate production line using PSA tin plating solution, the tin layer is soft melted using the diluted PSA tin plating solution; and on the tin plating line using MSA tin plating solution, the tin layer is soft melted generally using a special flux. Since the environmental protection of MSA tin plating solution is far better than that of PSA tin plating solution, the MSA tin plating solution system is used in more and more tin plating lines, and the components of MSA plating solution are not suitable for use as flux, so a special flux needs to be used in combination with MSA plating solution.

[0003] Chinese patent CN 103215623 B discloses an improved flux method for tin and tin alloys, wherein the flux composition includes one or more organic compounds having one or more sulfonic acid groups, salts thereof or anhydrides thereof; the flux composition is then homogenized on the tin or tin alloy to inhibit oxidation of the tin or tin alloy and to increase the brightness of the tin or tin alloy. U.S. Patent No. 6409850B1 discloses a composition used as a flux in a tin plating process to obtain a bright tin plating layer and a method for treating a matte tin-plated plate, wherein the composition comprises an aqueous solution of one or more hydroxyphenyl compounds of the general formula (I), wherein M = cationic species, preferably H, substituted or unsubstituted ammonium, alkali metal, alkaline earth metal or tin; R = H, C1-C6 straight or branched alkyl, alkoxy or alkenyl, or aryl (which may be substituted); m = 2 or 3; n = 0, 1 or 2, and the composition contains about 0.1 g / 1 to saturated compounds of the general formula (I).

[0004] In the prior art, the main function of flux or soldering agent is to obtain a bright tin-plated layer, and in order to achieve this goal, it is usually required to evenly apply the flux to the surface of the tin-plated plate. In order to achieve uniform distribution of the flux on the surface of the tin-plated plate, in addition to the good wettability of the flux itself, it is also hoped to improve the wettability of the surface of the tin-plated plate. The prior art is to dissolve and remove the tin oxide on the surface of the tin layer through the corrosion of the acid in the flux, but this brings a problem. After removing the tin oxide on the surface of the tin-plated plate, the corrosion resistance of the tin-plated plate is reduced. Through research and development, it is found that keeping a certain amount of tin oxide on the surface of the tin-plated plate does not cause poor surface wetting.

[0005] In view of this, it is urgent to develop a special flux for tinplate and a surface treatment method for tinplate, which can not only achieve the brightness of the tinplate layer, but also achieve micro-oxidation on the surface of the tinplate, thereby further enhancing the corrosion resistance of the tinplate. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of the present invention is to provide a flux for tinplate production and a tinplate surface treatment method, which can not only achieve the brightness of the tinplate layer, but also achieve micro-oxidation of the tinplate surface, thereby further enhancing the corrosion resistance of the tinplate.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a flux for tinplate production, a flux for tinplate production, characterized in that it comprises the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0009] The divalent stannate has a concentration of 0.1-3 g / L in terms of divalent tin ions;

[0010] The aminosulfonic acid and its salts have a concentration of 0.5-5 g / L based on aminosulfonate ions;

[0011] The concentration of the alkylphenol polyoxyethylene ether is 0.1-1g / L;

[0012] The concentration of the benzylideneacetone is 0.1-1g / L;

[0013] The concentration of the catechol is 0.5-3 g / L;

[0014] The concentration of the polyether is 0.05-0.5 g / L.

[0015] Preferably, the concentration of the divalent tin ions is 0.5-1.5 g / L; and / or

[0016] The concentration of the aminosulfonate ion is 1-3 g / L; and / or

[0017] The concentration of the alkylphenol polyoxyethylene ether is 0.2-0.5 g / L; and / or

[0018] The concentration of the benzylideneacetone is 0.2-0.6 g / L; and / or

[0019] The concentration of the catechol is 1-2 g / L; and / or

[0020] The concentration of the polyether is 0.1-0.3 g / L; and / or

[0021] The pH value of the flux used in the production of tinplate is 2-6, and the pH value is adjusted by using dilute sulfuric acid or sodium hydroxide.

[0022] Preferably, the divalent tin ion is selected from one or more of stannous sulfate, tin phenolsulfonate or tin methanesulfonate; and / or

[0023] The sulfamate ion is selected from one or more of sulfamate, sodium sulfamate, zinc sulfamate or ammonium sulfamate; and / or

[0024] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 800-2000 and a hydroxyl value between 53-130 mgKOH / g.

[0025] Preferably, the polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value ranging between 93-112 mgKOH / g.

[0026] Preferably, the pH of the flux for tinplate production is 2.5-4.

[0027] A second aspect of the present invention provides a tinplate surface treatment method, comprising the following steps:

[0028] (1) Soft fluxing: After the surface of the tinplate is cleaned, a flux for tinplate production is applied to the surface of the tinplate, and then a drying treatment is performed; the dried tinplate is then heated until the tin layer is completely melted, and then the heated tinplate is rapidly cooled;

[0029] (2) The tin-plated sheet after the reflow treatment is subjected to chromate electrolytic passivation and oiling treatment.

[0030] Preferably, in step (1), the coating method is immersion, spraying or immersion plus spraying; and / or

[0031] During the coating process, the use temperature of the flux for tinplate production is controlled to be 25-65° C., and the surface reaction time is 1-5 s; and / or

[0032] After the coating process is completed, the excess flux for tinplate production on the surface of the tinplate is squeezed out by a squeezing roller, and a flux water film layer is formed on the surface of the tinplate. The thickness of the flux water film layer is controlled to be 2-10 ml / m 2 ; and / or

[0033] The drying process uses hot air drying; and / or

[0034] During the drying process, the drying temperature is controlled to be 100-180°C; and / or

[0035] The heating method is resistance heating, induction heating or a combination of resistance heating and induction heating; and / or

[0036] The heating temperature is 235-315° C. and the holding time is 0.5-5 s; and / or

[0037] The rapid cooling process adopts water cooling process.

[0038] Preferably, in the step (1), during the coating process, the use temperature of the flux for tinplate production is 40-50° C.; and / or

[0039] The thickness of the co-solvent water film layer is 3-7 ml / m 2 ; and / or

[0040] The heating temperature is 240-290° C. and the holding time is 1-3 seconds; and / or

[0041] During the water cooling process, the water temperature is controlled at 50-90°C.

[0042] Preferably, in the step (1), during the water cooling process, the water temperature is controlled at 70-85°C.

[0043] Preferably, in step (2), during the chromate electrolytic passivation, the passivation charge is controlled to be 3-6C / dm 2 .

[0044] The proportioning principle of the flux for tinplate production of the present invention is:

[0045] The main function of divalent stannate is to provide an inducer for the soft melting reaction of the flux, the function of aminosulfonic acid root is to catalyze the soft melting reaction, alkylphenol polyoxyethylene ether as a non-ionic surfactant plays a role in making the flux fully wet the surface of the tinplate, benzyl acetone plays a role in increasing the surface brightness of the tin coating during the soft melting process, the main function of catechol is to inhibit the oxidation of divalent tin ions in the flux and the oxidation of some organic matter, and plays a role as a stabilizer in the flux, the function of polyether is to act as an auxiliary surfactant, and to play a defoaming role to prevent the flux from generating excessive foam during use.

[0046] The beneficial effects of the present invention are as follows:

[0047] 1. The flux for tinplate production and the surface treatment method of tinplate of the present invention can not only achieve the brightness of the tinplate layer, but also achieve micro-oxidation of the surface of the tin layer of the tinplate during the reflow process, thereby further enhancing the corrosion resistance of the tinplate;

[0048] 2. The surface treatment method of the tinplate of the present invention greatly enhances the corrosion resistance of the tinplate after the treatment, the tin layer grains are uniformly oriented, the alloy layer grains are densely and evenly arranged, the corrosion resistance is good, and it is not easy to produce defects such as uneven color after subsequent passivation treatment. DETAILED DESCRIPTION

[0049] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form.

[0050] The flux for tinplate production provided by the present invention comprises the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzyl acetone, catechol, polyether and water;

[0051] The concentration of divalent stannate is 0.1-3 g / L, preferably 0.5-1.5 g / L, calculated as divalent tin ions.

[0052] The concentration of aminosulfonic acid and its salts is 0.5-5 g / L, preferably 1-3 g / L, calculated as aminosulfonic acid ion;

[0053] The concentration of alkylphenol polyoxyethylene ether is 0.1-1g / L, preferably 0.2-0.5g / L;

[0054] The concentration of benzylideneacetone is 0.1-1 g / L, preferably 0.2-0.6 g / L;

[0055] The concentration of catechol is 0.5-3 g / L, preferably 1-2 g / L;

[0056] The concentration of the polyether is 0.05-0.5 g / L, preferably 0.1-0.3 g / L.

[0057] The pH of the flux used in the production of tinplate is 2-6, and the pH value is adjusted by using dilute sulfuric acid or sodium hydroxide, and the preferred pH value is 2.5-4.

[0058] Among the above components, the divalent tin ion is selected from one or more of stannous sulfate, tin phenolsulfonate or tin methanesulfonate; the aminosulfonate ion is selected from one or more of aminosulfonic acid, sodium aminosulfonate, zinc aminosulfonate or ammonium aminosulfonate; the polyether is selected from polyoxypropylene glycol with a relative molecular mass between 800-2000 and a hydroxyl value range between 53-130 mgKOH / g. In a further preferred embodiment, the polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value range between 93-112 mgKOH / g.

[0059] In the process of producing tinplate, after the steel plate is electroplated with tin, a matte tin layer will be deposited on the surface. This tin layer has many pores and poor corrosion resistance, so it cannot be directly used as the surface of the tinplate finished product and needs to be surface treated. The above-mentioned flux for tinplate production is used as a flux in the tinplate surface treatment method, and the tinplate surface treatment method includes the following steps:

[0060] (1) Soft flux treatment: After the surface of the tinplate is cleaned, the flux for tinplate production is applied to the surface of the tinplate, and then the tinplate is dried; the dried tinplate is then heated until the tin layer is completely melted, and then the heated tinplate is quickly cooled;

[0061] The specific process is as follows: before the surface treatment of the tinplate, the surface of the tinplate after electroplating needs to be fully cleaned. Generally, the method of rinsing with clean water is used to clean the residual plating solution on the surface of the tinplate, and then the above-mentioned flux for tinplate production is applied to the cleaned surface of the tinplate. After that, a surface reaction time of 1-5s is required to make the flux for tinplate production fully wet the surface of the tin layer and form a surface film on the surface of the tin layer. The coating method adopts immersion, spraying or immersion plus spraying. The use temperature of the flux for tinplate production is 25-65°C (in a further preferred embodiment, the use temperature of the flux for tinplate production is 40-50°C); then a pair of squeezing rollers are used to squeeze out the excess flux for tinplate production on the surface of the tin-plated layer coated with the flux for tinplate production, and a uniform flux water film layer is formed on the surface of the tinplate, and the thickness of the flux water film layer is controlled to be 2-10ml / m 2 The preferred thickness of the co-solvent water film layer is 3-7 ml / m 2; Then, hot air is used for surface drying treatment, and the moisture of the flux water film layer is completely dried by hot air with a drying temperature of 100-180°C; then the tinplate is heated by resistance heating, induction heating, or resistance heating and induction heating, and the heating temperature is controlled to be 235-315°C (that is, the tinplate is heated to a temperature within the range of 235-315°C), and then the holding time is controlled to be 0.5-5s at this temperature (in a further preferred embodiment, the heating temperature is 250-285°C, and the holding time is 1-3s). During this process, the tin layer melts and a tin-iron alloy layer is formed at the interface between the tin layer and the steel plate. Then the tinplate is quickly cooled to a certain temperature, generally using a water cooling treatment method, that is, the tinplate is directly put into water with a certain temperature, and the water temperature is controlled to be 50-90°C. In a further preferred embodiment, the water temperature is controlled to be 70-85°C.

[0062] (2) The tinplate after soft melting treatment is subjected to chromate electrolytic passivation and oiling treatment.

[0063] The specific process is as follows: the tinned plate after soft melting is passivated with a charge of 3-6C / dm 2 Chromate electrolytic passivation treatment is then carried out and oiling is performed.

[0064] During the above-mentioned tinplate surface treatment method, after the tinplate is soft-melted, a tin layer structure of pure tin + tin-iron alloy is formed on its surface, the corrosion resistance is greatly enhanced, the tin layer has uniform grain orientation, the alloy layer has dense and uniform grain arrangement, good corrosion resistance, and is not prone to defects such as uneven color after subsequent passivation treatment.

[0065] The flux for tinplate production and the surface treatment method of tinplate of the present invention are further described below with reference to specific examples; in the following embodiments, divalent tin ions are selected from stannous sulfate, tin phenolsulfonate or tin methanesulfonate; aminosulfonate ions are selected from aminosulfonic acid, sodium aminosulfonate, zinc aminosulfonate or ammonium aminosulfonate; polyether is selected from polyoxypropylene glycol with a relative molecular mass between 800-2000 and a hydroxyl value range of 53-130 mgKOH / g. In the following embodiments 1-8, the tinplate surface treatment method of the present invention is used, and the tin plating amount is 2.8 g / m 2 In Comparative Examples 1-3, conventional commercially available flux was used for treatment. The treatment method was as follows: the flux was evenly applied to the tin-plating amount of 2.8 g / m 2 The surface of the tinplate that has not been softened is squeezed dry with a water squeeze roller and dried with hot air, and then the tinplate is heated for softening and quenching, and then the surface of the tinplate is passivated.

[0066] Example 1

[0067] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0068] Wherein, the divalent stannate is stannous sulfate, and the concentration of divalent tin ions is 1 g / L;

[0069] Aminosulfonic acid and its salts use aminosulfonic acid, and the concentration of aminosulfonic acid ion is 1g / L;

[0070] The concentration of alkylphenol polyoxyethylene ether is 0.5g / L;

[0071] The concentration of benzylideneacetone was 0.4 g / L;

[0072] The concentration of catechol was 2 g / L;

[0073] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 800-2000 and a hydroxyl value between 53-130 mgKOH / g, and its concentration is 0.3 g / L;

[0074] The pH of the flux used in the production of the above-mentioned tinplate is 3.5-4.5.

[0075] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 40°C, the surface reaction time is 1.5s, and the thickness of the flux water film layer is 7ml / m 2 , the drying temperature is 180℃ during the drying treatment; the heating temperature is 245℃ during the heating treatment, the holding time is 2s, the water temperature is 70℃ during the water cooling treatment; during the passivation treatment after soft melting, 3C / dm 2 Passivation power treatment.

[0076] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0077] Example 2

[0078] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0079] Wherein, the divalent stannate is tin phenolsulfonate, and the concentration of divalent tin ions is 1 g / L;

[0080] The aminosulfonic acid and its salt adopt sodium aminosulfonate, and the concentration of aminosulfonate ion is 1g / L;

[0081] The concentration of alkylphenol polyoxyethylene ether is 0.2g / L;

[0082] The concentration of benzylideneacetone is 0.2 g / L;

[0083] The concentration of catechol was 1.5 g / L;

[0084] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.1 g / L;

[0085] The pH of the flux used in the production of the above-mentioned tinplate is 3.5-4.5.

[0086] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 40°C, the surface reaction time is 1s, and the thickness of the flux water film layer is 6ml / m 2 The drying temperature is 110℃ during the drying treatment; the heating temperature is 275℃ during the heating treatment, the holding time is 1s, the water temperature is 80℃ during the water cooling treatment; 4C / dm 2 Passivation power treatment.

[0087] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0088] Example 3

[0089] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0090] The divalent stannate is tin methanesulfonate, and the concentration of divalent tin ions is 1.5 g / L;

[0091] The aminosulfonic acid and its salt adopt potassium aminosulfonate, and the concentration of aminosulfonate ion is 0.6g / L;

[0092] The concentration of alkylphenol polyoxyethylene ether is 0.3g / L;

[0093] The concentration of benzylideneacetone was 0.6 g / L;

[0094] The concentration of catechol was 1 g / L;

[0095] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.2 g / L;

[0096] The pH of the flux used in the production of the above-mentioned tinplate is 4-5.

[0097] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 40°C, the surface reaction time is 3s, and the thickness of the flux water film layer is 5ml / m 2 The drying temperature is 170℃ during the drying treatment; the heating temperature is 260℃ during the heating treatment, the holding time is 2s, the water temperature is 85℃ during the water cooling treatment; during the passivation treatment after soft melting, 6C / dm 2 Passivation power treatment.

[0098] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0099] Example 4

[0100] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0101] The divalent stannate is tin phenolsulfonate, and the concentration of divalent tin ions is 1.5 g / L;

[0102] Ammonium sulfamate is used as sulfamate acid and its salt, and the concentration of sulfamate ion is 2.5 g / L;

[0103] The concentration of alkylphenol polyoxyethylene ether is 0.5g / L;

[0104] The concentration of benzylideneacetone is 0.2 g / L;

[0105] The concentration of catechol was 2 g / L;

[0106] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.3 g / L;

[0107] The pH of the flux used in the production of the above-mentioned tinplate is 3-4.

[0108] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 40°C, the surface reaction time is 4s, and the thickness of the flux water film layer is 5ml / m 2 The drying temperature is 165℃ during the drying treatment; the heating temperature is 245℃ during the heating treatment, the holding time is 3s, the water temperature is 80℃ during the water cooling treatment; 4C / dm 2 Passivation power treatment.

[0109] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0110] Example 5

[0111] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0112] Wherein, the divalent stannate is stannous sulfate, and the concentration of divalent tin ions is 2g / L;

[0113] The aminosulfonic acid and its salt adopt potassium aminosulfonate, and the concentration of aminosulfonate ion is 4g / L;

[0114] The concentration of alkylphenol polyoxyethylene ether is 0.3g / L;

[0115] The concentration of benzylideneacetone was 0.4 g / L;

[0116] The concentration of catechol was 1.5 g / L;

[0117] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.2 g / L;

[0118] The pH of the flux used in the production of the above-mentioned tinplate is 2.5-3.5.

[0119] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 40°C, the surface reaction time is 3.5s, and the thickness of the flux water film layer is 4.5ml / m 2 The drying temperature is 150℃ during the drying treatment; the heating temperature is 275℃ during the heating treatment, the holding time is 1s, the water temperature is 85℃ during the water cooling treatment; during the passivation treatment after soft melting, 4C / dm 2 Passivation power treatment.

[0120] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0121] Example 6

[0122] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0123] Wherein, the divalent stannate is tin phenolsulfonate, and the concentration of divalent tin ions is 2 g / L;

[0124] Aminosulfonic acid and its salts use aminosulfonic acid, and the concentration of aminosulfonic acid ion is 5g / L;

[0125] The concentration of alkylphenol polyoxyethylene ether is 0.2g / L;

[0126] The concentration of benzylideneacetone was 0.6 g / L;

[0127] The concentration of catechol was 1 g / L;

[0128] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.1 g / L;

[0129] The pH of the flux used in the production of the above-mentioned tinplate is 2-3.

[0130] In this embodiment, the flux for tinplate production is used in the surface treatment method of tinplate, wherein in the soft melting treatment, the coating method adopts immersion, the use temperature of the flux for tinplate production is 40°C, the surface reaction time is 2.5s, and the thickness of the flux water film layer is 3ml / m 2 The drying temperature is 160℃ during the drying treatment; the heating temperature is 260℃ during the heating treatment, the holding time is 2s, the water temperature is 75℃ during the water cooling treatment; during the passivation treatment after soft melting, 6C / dm 2 Passivation power treatment.

[0131] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0132] Example 7

[0133] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0134] Wherein, the divalent stannate is tin phenolsulfonate, and the concentration of divalent tin ions is 0.5 g / L;

[0135] The aminosulfonic acid and its salt adopt sodium aminosulfonate, and the concentration of aminosulfonate ion is 3g / L;

[0136] The concentration of alkylphenol polyoxyethylene ether is 1g / L;

[0137] The concentration of benzylideneacetone is 0.5 g / L;

[0138] The concentration of catechol was 3 g / L;

[0139] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.05 g / L;

[0140] The pH of the flux used in the production of the above-mentioned tinplate is 2.5-3.5.

[0141] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 25°C, the surface reaction time is 5s, and the thickness of the flux water film layer is 4ml / m 2 The drying temperature is 175℃ during the drying treatment; the heating temperature is 250℃ during the heating treatment, the holding time is 1s, the water temperature is 50℃ during the water cooling treatment; during the passivation treatment after soft melting, 5C / dm 2 Passivation power treatment.

[0142] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0143] Example 8

[0144] The flux for tinplate production in this embodiment has the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzylidene acetone, catechol, polyether and water;

[0145] The divalent stannate is tin phenolsulfonate, and the concentration of divalent tin ions is 4 g / L;

[0146] The aminosulfonic acid and its salt adopt sodium aminosulfonate, and the concentration of aminosulfonate ion is 0.5g / L;

[0147] The concentration of alkylphenol polyoxyethylene ether is 0.1g / L;

[0148] The concentration of benzylideneacetone is 1 g / L;

[0149] The concentration of catechol was 0.5 g / L;

[0150] The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g, and its concentration is 0.5 g / L;

[0151] The pH of the flux used in the production of the above-mentioned tinplate is 5-6.

[0152] In this embodiment, the flux for tinplate production is used in the tinplate surface treatment method. In the soft melting treatment, the coating method adopts immersion. The use temperature of the flux for tinplate production is 65°C, the surface reaction time is 1s, and the thickness of the flux water film layer is 2ml / m2 The drying temperature is 125℃ during the drying treatment; the heating temperature is 275℃ during the heating treatment, the holding time is 3s, the water temperature is 95℃ during the water cooling treatment; during the passivation treatment after soft melting, 5C / dm 2 Passivation power treatment.

[0153] After the above treatment, the tin-plated layer of the tinplate in this embodiment is bright and there is no uneven surface color.

[0154] Comparative Example 1

[0155] In this comparative example, a commercially available sulfonic acid-containing commercial flux is used in the tinplate surface treatment method. In the soft melting treatment, the use temperature of the sulfonic acid-containing commercial flux is 45°C, the soft melting temperature is 240°C, the holding time is 2s, and the water temperature during the water cooling treatment is 80°C; during the passivation treatment after soft melting, 3C / dm 2 Passivation power treatment.

[0156] After the above treatment, the surface of the tin plating becomes dark and the surface color is slightly uneven.

[0157] Comparative Example 2

[0158] In this comparative example, a commercially available sulfonic acid-containing commercial flux is used in the tinplate surface treatment method. In the soft melting treatment, the use temperature of the sulfonic acid-containing commercial flux is 50°C, the soft melting temperature is 260°C, the holding time is 2s, and the water temperature during the water cooling treatment is 80°C; during the passivation treatment after soft melting, 4C / dm 2 Passivation power treatment.

[0159] After the above treatment, the surface of the tin plating layer is bright, but the uneven surface color becomes more obvious.

[0160] Comparative Example 3

[0161] In this comparative example, a commercially available sulfonic acid-containing commercial flux is used in the tinplate surface treatment method. In the soft melting treatment, the use temperature of the sulfonic acid-containing commercial flux is 60°C, the soft melting temperature is 260°C, the holding time is 2s, and the water temperature during the water cooling treatment is 80°C; during the passivation treatment after soft melting, 6C / dm 2 Passivation power treatment.

[0162] After the above treatment, the surface of the tin plating is bright, but the uneven surface color becomes very obvious.

[0163] Corrosion resistance test

[0164] The iron dissolution value (ISV) test method in GB / T22316-2008 standard was used to test the tinplates treated in Examples 1-8 and Comparative Examples 1-3, and the test results were as follows:

[0165] The ISV value of the tin coating of the tinplate in Example 1 is 20.1 μg.

[0166] The ISV value of the tin coating of the tinplate in Example 2 is 18.3 μg.

[0167] The ISV value of the tin coating of the tinplate in Example 3 is 13.9 μg.

[0168] The ISV value of the tin coating of the tinplate in Example 4 is 17.7 μg.

[0169] The ISV value of the tin coating of the tinplate in Example 5 is 19.2 μg.

[0170] The ISV value of the tin coating of the tinplate in Example 6 is 14.5 μg 2 .

[0171] The ISV value of the tin coating of the tinplate in Example 7 is 16.5 μg.

[0172] The ISV value of the tin coating of the tinplate in Example 8 is 17.6 μg.

[0173] The ISV value of the tin coating of the tinplate in Comparative Example 1 is 25.8 μg.

[0174] The ISV value of the tin coating of the tin-plated sheet in Comparative Example 2 is 22.1 μg.

[0175] The ISV value of the tin coating of the tinplate in Comparative Example 3 is 19.5 μg.

[0176] In combination with Examples 1-8 and Comparative Examples 1-3, the surface of the tinplate treated in Examples 1-8 is bright and has uniform color. Under the same passivation power treatment conditions, the ISV of the tin coating of the tinplate treated in Example 1 is significantly smaller than that of Comparative Example 1, and the ISV of the tin coating of the tinplate treated in Examples 2-8 is significantly smaller than the ISV value of the tin coating of the tinplate in Comparative Examples 1-3. The smaller the ISV value, the stronger the corrosion resistance. Therefore, the corrosion resistance of the tinplate treated in the present invention is better than that of the tinplate treated in Comparative Examples 1-3.

[0177] It can be seen that the flux for tinplate production and the surface treatment method for tinplate of the present invention can not only achieve the brightness of the tinplate layer, but also achieve micro-oxidation on the surface of the tinplate, thereby further enhancing the corrosion resistance of the tinplate; after the tinplate is treated by the surface treatment method for tinplate of the present invention, the corrosion resistance is greatly enhanced, the tin layer grains are uniformly oriented, the alloy layer grains are densely and uniformly arranged, the corrosion resistance is good, and it is not easy to produce defects such as uneven color after subsequent passivation treatment.

[0178] In summary, the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A tinplate surface treatment method, characterized in that: The following steps are involved: (1) Soft fluxing: After the surface of the tinplate is cleaned, a flux for tinplate production is applied to the surface of the tinplate, and then a drying treatment is performed; the dried tinplate is then heated until the tin layer is completely melted, and then the heated tinplate is rapidly cooled; (2) subjecting the tinplate after the reflow treatment to chromate electrolytic passivation and oiling treatment, The flux for tinplate production comprises the following components: divalent stannate, aminosulfonic acid and its salt, alkylphenol polyoxyethylene ether, benzyl acetone, catechol, polyether and water; The divalent stannate has a concentration of 0.1-3 g / L in terms of divalent tin ions; The aminosulfonic acid and its salts have a concentration of 0.5-5 g / L based on aminosulfonic acid ions; The concentration of the alkylphenol polyoxyethylene ether is 0.1-1g / L; The concentration of the benzylideneacetone is 0.1-1g / L; The concentration of the catechol is 0.5-3 g / L; The concentration of the polyether is 0.05-0.5 g / L.

2. The tinplate surface treatment method according to claim 1, characterized in that: The concentration of the divalent tin ions is 0.5-1.5 g / L; The concentration of the aminosulfonate ion is 1-3 g / L; The concentration of the alkylphenol polyoxyethylene ether is 0.2-0.5 g / L; The concentration of the benzylideneacetone is 0.2-0.6 g / L; The concentration of the catechol is 1-2 g / L; The concentration of the polyether is 0.1-0.3 g / L; The pH value of the flux used in the production of tinplate is 2-6, and the pH value is adjusted by using dilute sulfuric acid or sodium hydroxide.

3. The tinplate surface treatment method according to claim 2, characterized in that: The divalent tin ion is selected from one or more of stannous sulfate, tin phenolsulfonate or tin methanesulfonate; The sulfamate ion is selected from one or more of sulfamate, sodium sulfamate, potassium sulfamate or ammonium sulfamate; The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 800-2000 and a hydroxyl value between 53-130 mgKOH / g.

4. The tinplate surface treatment method according to claim 3, characterized in that: The polyether is selected from polyoxypropylene glycol with a relative molecular mass between 1000-1200 and a hydroxyl value between 93-112 mgKOH / g.

5. The tinplate surface treatment method according to claim 2, characterized in that: The pH of the flux for tinplate production is 2.5-4.

6. The tinplate surface treatment method according to claim 1, characterized in that: In the step (1), the coating method is immersion, spraying or immersion plus spraying; During the coating process, the use temperature of the flux for tinplate production is controlled to be 25-65°C, and the surface reaction time is 1-5s; After the coating process is completed, the excess flux for tinplate production on the surface of the tinplate is squeezed out by a squeezing roller, and a flux water film layer is formed on the surface of the tinplate. The thickness of the flux water film layer is controlled to be 2-10 ml / m 2 ; Hot air drying is used in the drying process; During the drying process, the drying temperature is controlled to be 100-180°C; The heating method is resistance heating, induction heating or a combination of resistance heating and induction heating; The heating temperature is 235-315°C and the holding time is 0.5-5s; The rapid cooling process adopts water cooling process.

7. The tinplate surface treatment method according to claim 6, characterized in that: In the step (1), during the coating process, the use temperature of the flux for tinplate production is 40-50°C; The thickness of the co-solvent water film layer is 3-7 ml / m 2 ; The heating temperature is 245-285°C and the holding time is 1-3s; During the water cooling process, the water temperature is controlled at 50-90°C.

8. The tinplate surface treatment method according to claim 6, characterized in that: In the step (1), during the water cooling process, the water temperature is controlled to be 70-85°C.

9. The tinplate surface treatment method according to claim 6, characterized in that: In the step (2), during the chromate electrolytic passivation, the passivation charge is controlled to be 3-6C / dm 2 .