阅读说明：本技术 一种无铬压铸铝封闭剂、制备方法及其应用 (Chromium-free die-casting aluminum sealant, preparation method and application thereof ) 是由 段勇旭 秦远春 潘微 龙义福 于 2021-07-15 设计创作，主要内容包括：本发明公开了一种无铬压铸铝封闭剂、制备方法及其应用,所述封闭剂包括以下重量份的组份：3-缩水甘油醚氧丙基三甲氧基硅烷15-150份、水560-970份、无水乙醇10-100份、4-磺胺基苯甲酸或苯甲酸钠5-75份、壳聚糖或纤维素0.1-65份、硝酸铈或硝酸钴0.01-15份、纳米二氧化硅或水性硅溶胶0.1-10份、EDTA二钠或柠檬酸钠0.5-25份。本发明的无铬压铸铝封闭剂可以大幅度提高压铸铝的耐蚀性能,可以完全取代传统的六价铬钝化,且不含氟,还更加环境友好。(The invention discloses a chromium-free die-casting aluminum sealant, a preparation method and application thereof, wherein the sealant comprises the following components in parts by weight: 15-150 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 970 parts of water 560-. The chromium-free die-casting aluminum sealant disclosed by the invention can greatly improve the corrosion resistance of die-casting aluminum, can completely replace the traditional hexavalent chromium passivation, does not contain fluorine, and is more environment-friendly.)

1. The chromium-free die-casting aluminum sealant is characterized by comprising the following components in parts by weight: 15-150 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 970 parts of water 560-.

2. The chromium-free die-casting aluminum sealant as claimed in claim 1, wherein the sealant comprises the following components in parts by weight: 25-125 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 933 parts of water 647-.

3. The chromium-free die-casting aluminum sealant according to claim 1 or 2, which is characterized by comprising the following components in parts by weight: 35-100 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 900 parts of water 711-.

4. The chromium-free die-cast aluminum sealant according to claim 3, which comprises the following components in parts by weight: 50 parts of 3-glycidoxypropyltrimethoxysilane, 824.5 parts of water, 60 parts of absolute ethyl alcohol, 30 parts of 4-sulfanilic acid or sodium benzoate, 28 parts of chitosan or cellulose, 2 parts of cerium nitrate or cobalt nitrate, 0.5 part of nano silicon dioxide or aqueous silica sol and 5 parts of EDTA disodium or sodium citrate.

5. The preparation method of the chromium-free die-casting aluminum sealant as claimed in any one of claims 1 to 4, which is characterized by comprising the following steps: adding a certain weight part of 3-glycidol ether oxypropyl trimethoxy silane into a container, dropwise adding water under stirring, adding absolute ethyl alcohol after dropwise adding, stirring for 1.5-2.5 h, then adding 4-sulfanilic acid or sodium benzoate, adding chitosan or cellulose under stirring, stirring uniformly, then adding cerium nitrate or cobalt nitrate, nano silicon dioxide or aqueous silica sol, fully mixing uniformly, then adding EDTA disodium or sodium citrate, stirring uniformly, and adding the rest water to 1000 parts, thus obtaining the die-casting aluminum sealant.

6. The preparation method of the chromium-free die-casting aluminum sealant as claimed in claim 5, wherein the components in certain parts by weight are as follows: 15-150 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 970 parts of water 560-.

7. The method for preparing the chromium-free die-casting aluminum sealant according to claim 5, wherein the preparation process is carried out at normal temperature and normal pressure.

8. The preparation method of the chromium-free die-casting aluminum sealant according to claim 5, wherein the stirring speed is 300-600 rpm.

9. The use of the chromium-free die-casting aluminum sealant as claimed in any one of claims 1 to 4 or the chromium-free die-casting aluminum sealant prepared by the preparation method as claimed in any one of claims 5 to 8 in surface treatment of die-casting aluminum.

10. The chromium-free die-casting aluminum sealant according to claim 9, wherein the sealant is diluted by adding 15% by mass into water to form a die-casting aluminum sealant solution and then directly used.

Technical Field

The invention relates to the technical field of metal surface treatment, in particular to a die-casting aluminum sealing agent, a preparation method and application thereof.

Technical Field

The die-casting of aluminum is a process of metal smelting and processing, and is to cast in a die by utilizing the gravity of metal. "aluminum die casting" is not done by gravity, but rather by applying some pressure. Somewhat like "injection molding". But it has a set of systems with higher technical content, such as core-pulling, cooling, etc. In general, the parts are formed by feeding material through a centralized inlet into the cavity to be cast. The aluminum suitable for the die casting process is die cast aluminum, and is generally die cast aluminum alloy.

The die-cast aluminum has the following characteristics: the product quality is good, the size precision of the casting is high, generally equivalent to 6-7 grades, and even can reach 4 grades; the surface smoothness is good, and is generally equivalent to 5-8 grades; the strength and the hardness are higher, and the strength is generally improved by 25-30% compared with sand casting. ② the economic effect is excellent. Because die-casting aluminium casting size is accurate, advantage such as the table is bright and clean, generally no longer carry out machining and directly use, or the processing volume is very little, so both improved metal utilization ratio, reduced a large amount of processing equipment and man-hour again. In addition, the casting is low in price, and other metal or nonmetal materials can be used for combining die-casting aluminum, so that the assembly time is saved, and the metal is saved.

Along with the rapid industrial development, the requirement of the market on the corrosion resistance of die-casting aluminum is generally improved, and particularly, the existing hexavalent chromium chromate sealing agent in the current market is not environment-friendly and is difficult to treat waste water, so that the wide application of the die-casting aluminum is increasingly limited. In view of the above, it is very important to develop a die-casting aluminum sealant for replacing hexavalent chromium passivation, and the sealant is required to improve the corrosion resistance of a film layer after the surface treatment of a die-casting aluminum product and to be more environment-friendly than the hexavalent chromium sealant.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a chromium-free die-casting aluminum sealant which is required to improve the corrosion resistance of a film layer after the surface treatment of a die-casting aluminum product and maintain the natural color of a workpiece and is more environment-friendly than the traditional hexavalent chromium sealant.

The invention also aims to provide a preparation method of the chromium-free die-casting aluminum sealant.

The invention also aims to provide application of the chromium-free die-casting aluminum sealant in surface treatment of die-casting aluminum.

In order to achieve the above purpose, the invention adopts the following technical scheme:

a chromium-free die-casting aluminum sealant comprises the following components in parts by weight: 15-150 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 970 parts of water 560-.

In a specific embodiment, the sealant comprises the following components in parts by weight: 25-125 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 933 parts of water 647-.

In a preferred embodiment, the sealant comprises the following components in parts by weight: 35-100 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 900 parts of water 711-.

In a more preferred embodiment, the sealant comprises the following components in parts by weight: 50 parts of 3-glycidoxypropyltrimethoxysilane, 824.5 parts of water, 60 parts of absolute ethyl alcohol, 30 parts of 4-sulfanilic acid or sodium benzoate, 28 parts of chitosan or cellulose, 2 parts of cerium nitrate or cobalt nitrate, 0.5 part of nano silicon dioxide or aqueous silica sol and 5 parts of EDTA disodium or sodium citrate.

In another aspect of the present invention, the preparation method of the chromium-free die-casting aluminum sealant comprises the following steps: adding a certain weight part of 3-glycidol ether oxypropyl trimethoxy silane into a container, dropwise adding water under stirring, adding absolute ethyl alcohol after dropwise adding, stirring for 1.5-2.5 h, then adding 4-sulfanilic acid or sodium benzoate, adding chitosan or cellulose under stirring, stirring uniformly, then adding cerium nitrate or cobalt nitrate, nano silicon dioxide or aqueous silica sol, fully mixing uniformly, then adding EDTA disodium or sodium citrate, stirring uniformly, and adding the rest water to 1000 parts, thus obtaining the die-casting aluminum sealant.

In a specific embodiment, the components in a certain weight part are as follows: 15-150 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 970 parts of water 560-.

In a specific embodiment, the preparation process is carried out at normal temperature and normal pressure.

In a specific embodiment, the rotation speed of the stirring is 300-600 rpm.

In still another aspect of the present invention, the use of the foregoing chromium-free die cast aluminum sealant in the surface treatment of die cast aluminum is provided.

When the die-casting aluminum sealant is used specifically, the die-casting aluminum sealant is added into water according to the mass fraction of 15% to be diluted to form a die-casting aluminum sealant solution and then is directly used.

Compared with the prior art, the chromium-free die-casting aluminum sealant disclosed by the invention has at least the following beneficial effects:

(1) the chromium-free die-casting aluminum sealant can greatly improve the corrosion resistance of die-casting aluminum. After the die-casting aluminum product is treated, the salt spray resistance can reach 720h, the surface is free of corrosion, and the sealing agent is far better than the traditional sealing agent.

(2) The chromium-free die-casting aluminum sealant can completely replace the traditional hexavalent chromium passivation, does not contain fluorine and is more environment-friendly; the sealing agent can be used as a bare corrosion-resistant protective film after sealing treatment, and the film layer has lower contact resistance and obviously improved corrosion resistance.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The chromium-free die-casting aluminum sealant is prepared from the following components in parts by weight: 15-150 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 970 parts of water 560-.

In an alternative scheme, the composition is prepared from the following components in parts by weight: 15-150 parts of 3-glycidoxypropyltrimethoxysilane, 970 parts of water 560-.

In a preferred scheme, the traditional Chinese medicine composition is prepared from the following components in parts by weight: 50 parts of 3-glycidyl ether oxypropyltrimethoxysilane, 650 parts of water, 60 parts of absolute ethyl alcohol, 30 parts of 4-sulfanilamide benzoic acid, 28 parts of chitosan, 2 parts of cerium nitrate, 0.5 part of nano silicon dioxide and 5 parts of EDTA disodium.

The chromium-free die-casting aluminum sealant is prepared by the following specific steps: accurately weighing 3-glycidoxypropyltrimethoxysilane, adding the 3-glycidoxypropyltrimethoxysilane into a four-neck flask, dropwise adding water while stirring, adding ethanol after dropwise adding, stirring for 2 hours, adding 4-sulfanilic acid, adding chitosan while stirring, stirring uniformly, adding cerium nitrate and nano-silica, mixing uniformly, adding EDTA disodium, stirring uniformly, adding water to a scale of 1L, and obtaining the die-casting aluminum sealant.

The temperature and pressure in the preparation process are not particularly limited, and may be, for example, at normal temperature and normal pressure, or preferably at normal temperature and normal pressure. In addition, the preparation process mainly comprises the steps of mixing and uniformly stirring the components in sequence, the stirring speed is not particularly limited, and can be adjusted according to the actual situation, for example, the stirring speed is 300-600 rpm, but is not limited thereto.

The chromium-free die casting aluminum sealant of the invention needs to be diluted when in use, for example, the die casting aluminum sealant is diluted by adding the die casting aluminum sealant into water according to the mass fraction of 15 percent, so that a die casting aluminum sealant solution can be obtained and used separately.

The invention is further illustrated, but not limited, by the following more specific examples.

Without being particularly specified, the main raw materials of the examples of the present invention and comparative examples are commercially available.

Among them, testing of corrosion properties of passivation film

Detecting the prepared die-casting aluminum test plate, wherein the detection is as follows:

(1) salt spray resistance test

The die cast aluminum panels were placed in a salt spray test chamber and tested continuously for 720 hours, expressed as area of panel blackening/area of test panel (%). The salt spray test is carried out according to the ASTMB117-03 standard, and the set conditions of the salt spray box are 35 +/-1 ℃ of temperature, 47 +/-1 ℃ of saturated air, 5 +/-l% of salt water mass concentration, 6.5-7.2 of pH value and 1-2 ml of spray amount per 80 square centimeters per hour.

(2) Conductivity test

The surface contact resistance of the sample is measured by using a microohm meter, two electrodes are in contact with the measured surface, and the area of the electrodes is 1 cm²And the electrode pressure is 1.4MPa, two points are arbitrarily selected on the surface of the sample for measurement, and the average value (not more than 15m omega) is obtained after 3 times of tests.

Example 1

Accurately weighing 40g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 50g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 25g of 4-sulfanilic acid, adding 32g of chitosan under stirring, uniformly stirring, adding 2g of cerium nitrate and 0.5g of nano silicon dioxide, fully and uniformly mixing, adding 8g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 2

Accurately weighing 40g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 50g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 35g of 4-sulfanilic acid, adding 25g of chitosan under stirring, uniformly stirring, then adding 3g of cerium nitrate and 0.7g of nano silicon dioxide, fully and uniformly mixing, then adding 6g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 3

Accurately weighing 40g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 50g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 38g of 4-sulfanilic acid, adding 28g of chitosan under stirring, uniformly stirring, adding 1g of cerium nitrate and 1g of nano-silica, fully and uniformly mixing, adding 6g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 4

Accurately weighing 45g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 60g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 25g of 4-sulfanilic acid, adding 28g of chitosan under stirring, uniformly stirring, adding 3g of cerium nitrate and 1g of nano-silica, fully and uniformly mixing, adding 10g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 5

Accurately weighing 50g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 60g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 25g of 4-sulfanilic acid, adding 30g of chitosan under stirring, uniformly stirring, adding 2g of cerium nitrate and 0.5g of nano silicon dioxide, fully and uniformly mixing, adding 5g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 6

Accurately weighing 15g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 100g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 75g of 4-sulfanilic acid, adding 65g of chitosan under stirring, uniformly stirring, adding 15g of cerium nitrate and 0.1g of nano silicon dioxide, fully and uniformly mixing, adding 0.5g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 7

Accurately weighing 150g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 10g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 5g of 4-sulfanilic acid, adding 1g of chitosan under stirring, uniformly stirring, then adding 1g of cerium nitrate and 10g of nano-silica, fully mixing uniformly, then adding 25g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 8

Accurately weighing 80g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 20g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 60g of 4-sulfanilic acid, adding 50g of chitosan under stirring, uniformly stirring, then adding 10g of cerium nitrate and 0.2g of nano silicon dioxide, fully and uniformly mixing, then adding 1g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 9

Accurately weighing 125g of 3-glycidoxypropyltrimethoxysilane, adding the 3-glycidoxypropyltrimethoxysilane into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 80g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 15g of 4-sulfanilic acid, adding 5g of chitosan under stirring, uniformly stirring, then adding 1.5g of cerium nitrate and 8g of nano silicon dioxide, fully and uniformly mixing, then adding 20g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 10

Accurately weighing 50g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water while stirring, adding 60g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 25g of sodium benzoate, adding 30g of chitosan while stirring, uniformly stirring, adding 2g of cerium nitrate and 0.5g of nano-silica, fully and uniformly mixing, adding 5g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 11

Accurately weighing 15g of 3-glycidol ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 100g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 75g of 4-sulfanilic acid, adding 65g of cellulose under stirring, uniformly stirring, then adding 15g of cerium nitrate and 0.1g of nano silicon dioxide, fully and uniformly mixing, then adding 5g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 12

Accurately weighing 150g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 10g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 5g of 4-sulfanilic acid, adding 1g of chitosan under stirring, uniformly stirring, then adding 1g of cobalt nitrate and 10g of nano-silica, fully mixing uniformly, then adding 25g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 13

Accurately weighing 80g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 20g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, then adding 60g of 4-sulfanilic acid, adding 50g of chitosan under stirring, uniformly stirring, then adding 10g of cerium nitrate and 0.2g of aqueous silica sol, fully and uniformly mixing, then adding 1g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Example 14

Accurately weighing 125g of 3-glycidyl ether oxypropyl trimethoxy silane, adding into a 2L four-neck flask, dropwise adding 500g of water under stirring, adding 80g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 15g of 4-sulfanilic acid, adding 5g of chitosan under stirring, uniformly stirring, adding 1.5g of cerium nitrate and 8g of nano silicon dioxide, fully and uniformly mixing, adding 20g of sodium citrate, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealant.

Comparative example 1

Accurately weighing 40g of KH550 silane coupling agent, adding into a 2L four-neck flask, dropwise adding 500g of water while stirring, adding 50g of absolute ethanol after dropwise adding, stirring for 2 hours, adding 25g of 4-sulfanilic acid, adding 32g of chitosan while stirring, uniformly stirring, adding 2g of cerium nitrate and 0.5g of nano-silica, fully mixing uniformly, adding 8g of EDTA disodium, uniformly stirring, and adding water to 1L to obtain the die-casting aluminum sealing agent.

Comparative example 2

Accurately weighing 40g of aminosilane, adding the aminosilane into a 2L four-neck flask, dropwise adding 500g of water while stirring, adding 50g of absolute ethyl alcohol after dropwise adding, stirring for 2h, adding 35g of 4-sulfanilic acid, adding 25g of chitosan while stirring, uniformly stirring, adding 3g of cerium nitrate and 0.7g of nano silicon dioxide, fully and uniformly mixing, adding 6g of EDTA disodium, uniformly stirring, and adding 1L of water to obtain the die-casting aluminum sealant.

Comparative example 3

Accurately weighing 40g of epoxy silane, adding the epoxy silane into a 2L four-neck flask, dropwise adding 500g of water while stirring, adding 50g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 38g of 4-sulfanilic acid, adding 28g of chitosan while stirring, uniformly stirring, adding 1g of cerium nitrate and 1g of nano silicon dioxide, fully mixing uniformly, adding 6g of EDTA disodium, uniformly stirring, and adding 1L of water to obtain the die-casting aluminum sealant.

Comparative example 4

Accurately weighing 45g of triethoxymethylsilane, adding the triethoxymethylsilane into a 2L four-neck flask, dropwise adding 500g of water while stirring, adding 60g of absolute ethyl alcohol after dropwise adding, stirring for 2 hours, adding 25g of 4-sulfanilic acid, adding 28g of chitosan while stirring uniformly, adding 3g of cerium nitrate and 1g of nano silicon dioxide, fully mixing uniformly, adding 10g of EDTA disodium, stirring uniformly, and adding 1L of water to obtain the die-casting aluminum sealant.

The chromium-free die-casting aluminum sealant is used in the experimental process:

adding the die-casting aluminum sealant into water for dilution according to the mass fraction of 15%, thereby obtaining a die-casting aluminum sealant solution. Taking a die-cast aluminum test plate, and carrying out ultrasonic degreasing and cleaning on the surface of the test plate by using a weakly alkaline degreasing agent to remove oil contamination impurities; carrying out trivalent chromium passivation after washing; washing with water, soaking in sealant solution at room temperature for 6min, washing with pure water, and oven drying at 100 deg.C for 30 min.

And (3) carrying out relevant performance tests on the die-cast aluminum after soaking and drying according to the salt spray resistance test method and the conductivity method, wherein the test results are shown in the following table:

the analysis on the table shows that the corrosion resistance of the die-casting aluminum sealing agent prepared by the invention in neutral salt spray test of the processed die-casting aluminum product reaches over 720h, the corrosion resistance of the processed die-casting aluminum product in alternative solution also reaches over 430h, the salt spray resistance of the die-casting aluminum sealing agent is obviously superior to that of the comparative example, and the die-casting aluminum sealing agent has good conductivity.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.