A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide, its preparation method and application

Abstract

The present invention discloses a condensate-type automotive cavity anti-corrosion wax composite with graphene oxide, and its preparation method and application. This anti-corrosion wax is mainly used for anti-corrosion of automotive cavities, especially for the gap parts that require permeability, and plays the roles of penetration, filling, and anti-corrosion. Its main components include graphene oxide, solid paraffin, oil-based graphite dispersant, 1,2-polybutadiene, liquid paraffin, and drier. Spraying the present invention at room temperature on the inner wall or gaps of automotive cavities, in order to ensure full filling without missing coating, it is necessary to inject wax appropriately in excess, and then flash dry at 60-70 °C in the drying oven for 1 minute, and the anti-corrosion wax can achieve the effect of condensate flash drying without flowing, that is, the surface dry state. It solves the problems that the surface drying time of traditional automotive cavity anti-corrosion wax is slow and it is easy to overflow from the drain holes during the natural drying stage after wax spraying construction in the painting workshop.

Description

Technical Field

[0001] The invention belongs to the field of anti-corrosion waxes, and in particular relates to a graphene oxide composite condensation type automobile cavity anti-corrosion wax used in the automobile field. Background Art

[0002] With the scale and industrialization of the automobile industry, the problem of rust has gradually increased. Automobile cavity rust has been a thorny problem that has always plagued automobile OEMs. The traditional cavity anti-corrosion method generally uses solvent-based cavity protection wax, which is sprayed on the door or chassis crossbeam and longitudinal beam through airless spraying. However, since the anti-corrosion wax is in liquid state, overspraying will cause flow, which will pollute the subsequent assembly workshop and cause excessive VOC, resulting in odor in the car. In order to control the flow, controlling the spraying amount will cause missing coating, and the purpose of anti-corrosion will not be fully achieved. Therefore, the research and development of cavity anti-corrosion wax for automobile cavities has always been an eternal topic for scientific researchers. Summary of the invention

[0003] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a graphene oxide composite condensed type automobile cavity anti-corrosion wax. The condensed type automobile cavity anti-corrosion wax provided by the present invention can achieve a condensed gel effect in a relatively short time at 60°C, and can be completely dried as it is gradually oxidized and dried. It does not contain any solvents and reaches nearly 100% solid content. Moreover, under the protection of graphene oxide, it has excellent anti-corrosion effect.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a graphene oxide composite condensation type automobile cavity anti-corrosion wax, which includes 2-5 parts of graphene oxide, 15-35 parts of solid paraffin, 0.2 parts of oily graphite dispersant, 15-25 parts of 1,2 polybutadiene, 30-50 parts of liquid paraffin and 0.1-0.5 parts of drying agent in parts by weight.

[0005] Furthermore, the preparation method of graphene oxide includes the following steps: taking an appropriate amount of graphite powder and adding it to a container, and adding an appropriate amount of deionized water and an aqueous dispersant, after ultrasonic dispersion for 10 minutes, slowly adding concentrated sulfuric acid and fluorozirconic acid to the container, slowly heating the container to 50°C, and stirring for 5 minutes; then slowly adding potassium permanganate in batches, continuing to stir for 12 hours, and then very slowly adding a trace amount of hydrogen peroxide to the container, continuing to stir for 1 hour, the solution changes from black to bright yellow, and stops when no bubbles are generated, and the obtained reaction product is centrifuged and washed with deionized water until the pH is 6-7, concentrating the product, vacuum drying at 60°C, and grinding to obtain graphene oxide.

[0006] Furthermore, the aqueous dispersant is selected from BKY 190.

[0007] Furthermore, the solid paraffin is selected from No. 56 fully refined paraffin.

[0008] Further, the liquid paraffin is selected from heavy liquid paraffin.

[0009] Further, the oily graphite dispersant is selected from one or two of the products named DISPERBYK-2117 or SP-4320, and its amine value is 20-30 KOH / g.

[0010] Further, the 1,2-polybutadiene is selected from one or two of the products named Lithene PM4 or Lithene N4-9000 and is 1,2-polybutadiene with a 1,2-vinyl microstructure.

[0011] Further, the drier is selected from one, two or three of zirconium octoate, cerium octoate and manganese octoate.

[0012] A preparation method of a graphene oxide composite condensate type automotive cavity anti-corrosion wax, comprising the following steps:

[0013] 1) Preparation of paraffin / graphene oxide microcapsules: After heating and melting solid paraffin, add the ground graphene oxide powder and the oily graphite dispersant, disperse at high speed for 30 min under a vacuum and negative pressure environment, and granulate the obtained mixed wax powder to make paraffin / graphene oxide microcapsule wax powder with a particle size of about 75 microns;

[0014] 2) Add 1,2-polybutadiene to liquid paraffin, heat to 60 °C, and stir for 30 min; after cooling to 20 °C, add the paraffin / graphene oxide microcapsule wax powder obtained in step 1), disperse at high speed for 10 min, then add the drier, and continue to stir for 10 min to obtain the graphene oxide composite condensate type automotive cavity anti-corrosion wax.

[0015] Further, in step 1), during the granulation process of the obtained mixed wax powder, the mixed wax powder adheres to soybean wax on the surface during the rolling process on a drum machine with soybean wax attached to the surface.

[0016] Further, the soybean wax is hydrogenated soybean wax with a melting point of 51-55 °C.

[0017] The application of a graphene oxide composite condensate type automotive cavity anti-corrosion wax provided by the present invention in automotive cavity anti-corrosion.

[0018] Compared with the traditional technology, the beneficial effects of the present invention are as follows:

[0019] 1. The condensate-type automotive cavity anti-corrosion wax composite with graphene oxide provided by the present invention changes the film-forming mechanism of traditional solvent-based anti-corrosion waxes through the volatilization of solvents or moisture. Through the paraffin / graphene oxide microcapsule structure, wrapped with soybean wax on the outside, it is dispersed in heavy liquid paraffin and 1,2-polybutadiene, and through medium-high temperature flash drying, the purpose of surface drying is achieved. At the same time, the through-drying is achieved through the oxygen curing mechanism, using the cross-linking reaction of 1,2-polybutadiene and metal driers to further realize the through-drying effect and improve the film-forming dropping point. At the same time, the use of 1,2-polybutadiene avoids the risk of damaging the outer layer of soybean wax at room temperature caused by the use of alkyd resin or vegetable oil, and has a lower odor.

[0020] 2. The condensate-type automotive cavity anti-corrosion wax composite with graphene oxide provided by the present invention uses the combined action of 1,2-polybutadiene, paraffin, and graphene oxide treated with zirconium fluozirconate to form an anti-corrosion film, which is denser, has a higher cross-linking degree, a stronger shielding effect, and better anti-corrosion performance. For traditional solvent-based anti-corrosion waxes, the general salt spray time is 720h, for water-based anti-corrosion waxes it is 480h, and for fully solid-containing anti-corrosion waxes it is 1000h. The condensate-type automotive cavity anti-corrosion wax of the present invention can reach more than 2400h in the salt spray test, which is more than 3 times that of traditional solvent-based anti-corrosion waxes.

[0021] 3. In the graphene oxide used in the preparation of the condensate-type automotive cavity anti-corrosion wax provided by the present invention, the zirconium element in the zirconium fluozirconate can passivate the metal surface and shield the corrosive medium, and has better anti-corrosion performance than traditional graphene oxide.

[0022] 4. The condensate-type automotive cavity anti-corrosion wax composite with graphene oxide forms a microcapsule structure by combining graphene oxide with solid paraffin and is dispersed in liquid paraffin. Since the melting point of solid paraffin is around 56°C, when the flash drying temperature reaches 60°C, the solid paraffin becomes liquid and overflows from the hollow structure of graphene oxide. The solid paraffin mixes with the liquid paraffin. During the subsequent air cooling process, wax crystals rapidly precipitate and encapsulate part of the liquid paraffin, forming a semi-solid gel state to achieve the surface drying effect. In the present invention, the paraffin / graphene oxide microcapsule structure is adopted to solve the problem of the long surface drying time of the cavity protection wax. Graphene oxide is a powdery substance with a hollow layered structure. Under the action of an oil-based dispersant, liquid paraffin No. 56 reaching its melting point is filled into the hollow layered structure of graphene oxide, and the graphene oxide filled with paraffin is used as the core to spray and make fine particle size wax powder. To avoid the product viscosity increase caused by the dissolution of the surface wax powder when the wax powder is dispersed in liquid paraffin, a layer of plant soybean wax is wrapped on its surface during the production of the wax powder to delay the dissolution of the surface layer of paraffin wax powder No. 56 during dispersion. During use, the paraffin / graphene oxide microcapsule structure is dispersed and suspended in heavy liquid paraffin and is very stable at normal temperature (≤35°C). After being sprayed onto the automotive cavity, due to its very good fluidity, it can fully penetrate into the cavity gaps to form good adhesion and filling. When the automotive body passes through the flash drying line, the hot air quickly conducts heat through the metal sheet to raise the wax temperature above 60°C. The low melting point soybean wax first ruptures, and then the paraffin liquefies and oozes out after reaching its melting point, including the paraffin inside the graphene oxide layered structure, which is miscible with the heavy liquid paraffin. After air cooling, the temperature drops sharply, the paraffin crystallizes and becomes viscous, and encapsulates the heavy liquid paraffin to form a semi-solid state. The whole process takes 1 minute to achieve the purpose of rapid surface drying.

[0023] 5. To prevent possible high-temperature situations during the later use of the whole vehicle, it is necessary to solve the problem of actual drying after surface drying. The condensate-type automotive cavity anti-corrosion wax composite with graphene oxide provided by the present invention adds 1,2-polybutadiene with an unsaturated structure (1,2-vinyl microstructure). Under the action of a metal drier and oxygen, it can gradually crosslink and form a film at normal temperature to achieve the effect of actual drying and reach a completely dry state in 72 hours, enabling the cavity protection wax to withstand high temperatures above 90°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a mechanism diagram of a condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to the present invention.

[0025] Figure 2 It is an application process diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will be described in detail below with reference to the embodiments.

[0027] Example 1 A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide

[0028] (1) The formulation composition is as follows

[0029] By weight ratio,

[0030]

[0031] In this example, the 1,2-polybutadiene used is a 1,2-polybutadiene product with a 1,2-vinyl microstructure and a trade name of Lithene PM4.

[0032] In this example, the oil-based graphite dispersant is a dispersant with a trade name of DISPERBYK-2117.

[0033] (2) The preparation method is as follows:

[0034] 1. Preparation of graphene oxide:

[0035] Take 1.5 g of graphite powder and add it to a container, then add 20 g of deionized water and 0.05 g of water-based dispersant BKY 190, and ultrasonically disperse for 10 min. After forming a homogeneous solution, slowly add 80 g of concentrated sulfuric acid and 20 g of zirconium fluoride to the container, slowly heat the container to 50 °C, and keep it warm and stir for 5 min; then slowly add 9 g of potassium permanganate in batches, continue to keep it warm and stir for 12 h, and then very slowly drop a small amount of hydrogen peroxide into the container, with the criterion of not increasing the reaction temperature too quickly (the dropping process lasts for 1 h), until the solution changes from black to slightly purple and finally to bright yellow and stops generating bubbles, continue to keep it warm and stir for 1 h. Wash the obtained reaction product with deionized water by centrifugation until the pH is 6-7, concentrate the product, dry it in vacuum at 60 °C, and grind it to a particle size of less than 25 microns to obtain graphene oxide for standby.

[0036] 2. Preparation of paraffin / graphene oxide microcapsules:

[0037] Heat 32 g of No. 56 fully refined paraffin to 70 °C until it is completely melted, then add 2 g of ground graphene oxide powder and 0.2 g of oil-based graphite dispersant, and disperse at high speed for 30 min. The whole process is carried out in a vacuum and negative pressure environment to obtain mixed wax powder. Use a fully automatic drum machine to granulate the obtained mixed wax powder. During the powder spraying process, 2 g of hydrogenated soybean wax with a melting point of 51 °C is attached to the drum. The mixed wax powder will attach soybean wax on the surface during the tumbling process, and the attachment thickness is 3-5 microns, forming wax powder with a paraffin / graphene oxide microcapsule structure and a particle size of about 75 microns. During the subsequent dispersion process of this wax powder in liquid paraffin, the viscosity of the solution will not increase due to the microdissolution of solid paraffin and liquid paraffin.

[0038] 3. Preparation of Condensed Automotive Cavity Anticorrosive Wax Composed of Graphene Oxide:

[0039] Add 18.5 g of 1,2-polybutadiene to 45 g of liquid paraffin, heat to 60 °C, and stir for 30 min; after cooling to 20 °C, add the paraffin / graphene oxide microcapsule wax powder obtained in Step 2, disperse at a high speed of 1200 revolutions per minute for 10 min, then add driers (0.2 g of cerium isooctanoate and 0.1 g of zirconium isooctanoate), and continue to stir for 10 min to obtain the condensed automotive cavity anticorrosive wax composed of graphene oxide.

[0040] (III) Comparative Examples and Performance Testing

[0041] 1. Comparative Example 1

[0042] Add 33 g of fully refined paraffin wax No. 56 to 47 g of liquid paraffin, heat to 60 °C, and stir for 30 min; then add 20 g of 1,2-polybutadiene (trade name: Lithene PM4), disperse at a high speed of 1200 revolutions per minute for 10 min, then add driers (0.2 g of cerium isooctanoate and 0.1 g of zirconium isooctanoate), and continue to stir for 10 min to obtain the anticorrosive wax.

[0043] 2. Comparative Example 2

[0044] The preparation method is the same as that in (II). The difference is that in Step 2, during the granulation process of the obtained mixture using a fully automatic rotary drum machine, during the powder spraying process, hydrogenated soybean wax with a melting point of 51 °C does not adhere to the rotary drum.

[0045] 3. Comparative Example 3

[0046] The preparation method is the same as that in (II). The difference is that in Step 1, during the preparation of graphene oxide, phosphoric acid is used to replace zirconium fluozirconate.

[0047] 4. Comparative Example 4

[0048] The preparation method is the same as that in (II). The difference is that in Step 3, linseed oil is used to replace 1,2-polybutadiene.

[0049] The specific detection technical indicators are shown in Table 1:

[0050] Table 1 Performance Comparison of Automotive Cavity Anticorrosive Waxes Prepared in Examples and Comparative Examples

[0051]

[0052] ① Note: Increased from 950 cps to 7790 cps

[0053] As can be seen from Table 1, in Comparative Example 1, the lack of the paraffin / graphene oxide microcapsule structure led to a decline in rust prevention performance, and neither the surface drying time nor the through drying time could meet the requirements of body production; in Comparative Example 2, due to the lack of surface protection for the paraffin / graphene oxide powder, there was a phenomenon of slight dissolution of solid paraffin and liquid paraffin during long-term contact, resulting in an increase in viscosity and being unfavorable for construction; in Comparative Example 3, phosphoric acid in the reaction process was used to replace zirconium fluozirate, and after testing, the rust prevention performance was only at the level of traditional solvent-based rust prevention wax, less than 1 / 3 of that of the present invention; in Comparative Example 4, linseed oil was used to replace 1,2-polybutadiene with the trade name Lithene PM4, and the salt spray performance decreased in the test data, indicating that the film-forming compactness was inferior to that of the present invention, and the through drying did not meet the standard, indicating that the dryness was inferior to that of the present invention.

[0054] The action mechanism of the condensate-type automotive cavity anti-corrosion wax provided by the present invention is as follows: as Figure 1 shown, during the surface drying process, for the body sprayed with the anti-corrosion wax, after passing through the flash drying and baking line, the temperature is quickly conducted from the hot air to the anti-corrosion wax through the metal sheet. When the temperature gradually rises, the low-melting-point soybean wax first melts, and the microcapsule structure is damaged. When the temperature reaches 60 °C, the paraffin completely melts and migrates out of the graphene oxide structure, mixing with the liquid paraffin and liquid 1,2-polybutadiene. At the same time, the graphene oxide powder is also dispersed in this liquid. The "vacated" interlayer structure of graphene oxide will also absorb some oils and gradually adsorb and arrange on the metal surface to form a barrier-type protective layer. When the body exits the baking line and encounters a strong cooling process, the temperature of the paraffin quickly returns below the melting point, with a temperature difference of 20 - 30 °C. The wax crystal form becomes coarser, the viscosity suddenly increases, and it forms a gel-state oil-wax semi-solid form by wrapping the liquid paraffin. This form reaches the surface dry state and no longer has fluidity at room temperature.

[0055] The application of the condensate-type automotive cavity anti-corrosion wax compounded with graphene oxide provided by the present invention in automotive cavity anti-corrosion. In actual application, as Figure 2 , when the body moves to the wax spraying room, it is sprayed at the designated station, mainly targeting the folded edge gaps inside the car doors. When the body sprayed with the anti-corrosion wax passes through the baking tunnel, when the anti-corrosion wax is heated to 60 °C, it reaches the lowest viscosity state in about 1 minute, forming a good filling effect on the gaps. Then, after air cooling, the wax reaches the normal temperature state from 60 °C in a short time. The rapid temperature difference makes the wax crystal form coarser and precipitate, and the viscosity increases sharply, reaching the gel state, that is, the surface dry state, and the drying speed is only affected by the temperature and not by the film thickness.

Claims

1. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide, Characterized in that, The condensate-type automotive cavity anti-corrosion wax, by weight ratio, includes 2-5 parts of graphene oxide, 15-35 parts of solid paraffin, 0.2 part of oil-based graphite dispersant, 15-25 parts of 1,2-polybutadiene, 30-50 parts of liquid paraffin, and 0.1-0.5 part of drier, The preparation method includes the following steps: 1) Preparation of paraffin / graphene oxide microcapsules: After heating and melting solid paraffin, add the ground graphene oxide powder and oil-based graphite dispersant, disperse at high speed for 30 min under vacuum and negative pressure environment, and granulate the obtained mixed wax powder to form paraffin / graphene oxide microcapsule wax powder with a particle size of 75 microns; 2) Add 1,2-polybutadiene to liquid paraffin, heat to 60 °C, and stir for 30 min; after cooling to 20 °C, add the paraffin / graphene oxide microcapsule wax powder obtained in step 1), disperse at high speed for 10 min, then add the drier, and continue to stir for 10 min to obtain the condensate-type automotive cavity anti-corrosion wax composite with graphene oxide.

2. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 1, Characterized in that, The preparation method of the graphene oxide includes the following steps: Take an appropriate amount of graphite powder and add it to a container, and add an appropriate amount of deionized water and water-based dispersant. After ultrasonic dispersion for 10 min, slowly add concentrated sulfuric acid and zirconium fluoride to the container, slowly heat the container to 50 °C, and keep stirring for 5 min; then add potassium permanganate in batches slowly, continue to keep stirring for 12 h, then very slowly drop a small amount of hydrogen peroxide into the container, continue to keep stirring for 1 h, the solution changes from black to bright yellow, and stop when no more bubbles are generated. Wash the obtained reaction product with deionized water by centrifugation until the pH is 6-7, concentrate the product, dry it under vacuum at 60 °C, and grind it to obtain graphene oxide.

3. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 2, Characterized in that, The water-based dispersant is selected from BKY 190.

4. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 1, Characterized in that, The solid paraffin is selected from No. 56 fully refined paraffin; the liquid paraffin is selected from heavy liquid paraffin; the oil-based graphite dispersant is selected from one or two of the products named DISPERBYK-2117 or SP-4320, and its amine value is 20-30 KOH / g.

5. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 1, Characterized in that, The 1,2-polybutadiene is selected from one or two of the products named Lithene ultra® PM4 or Lithene ultra® N4-9000, and is 1,2-polybutadiene with a 1,2-vinyl microstructure.

6. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 1, Characterized in that, The drier is selected from one, two or three of zirconium isooctanoate, cerium isooctanoate and manganese isooctanoate.

7. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide, characterized in that, in step 1), during the granulation of the obtained mixed wax powder, the mixed wax powder is tumbled on a drum machine with a layer of soybean wax attached to its surface, and soybean wax adheres to the surface during the tumbling process.

8. A condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 7, characterized in that, the soybean wax is hydrogenated soybean wax with a melting point of 51-55 °C.

9. Application of the condensate-type automotive cavity anti-corrosion wax composite with graphene oxide according to claim 1 in automotive cavity anti-corrosion.

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