High and low temperature resistant water-based peelable protective coating and preparation method thereof

Abstract

The invention provides a high and low temperature resistant water-based peelable protective coating and a preparation method thereof, and relates to the technical field of coating preparation. The high and low temperature resistant water-based peelable protective coating is prepared from the following components in parts by weight: 30 to 50 parts of polyurethane emulsion, 20 to 30 parts of epoxy resin, 20 to 30 parts of acrylic emulsion, 10 to 15 parts of polytetrafluoroethylene, 20 to 30 parts of filler, 10 to 20 parts of auxiliaries and the balance of water. According to the invention, the polyurethane emulsion, the epoxy resin and the acrylic emulsion are used as main film-forming substances, and the stable performance of the coating in a wide temperature range is realized through scientific proportioning and process optimization. The polyurethane emulsion endows the coating with good flexibility and wear resistance, the epoxy resin improves the hardness and adhesive force of the coating, and the acrylic emulsion enhances the weather resistance and water resistance of the coating. Through the synergistic effect of the three components, the coating can still keep stable physical and chemical properties in an extremely high-temperature or low-temperature environment, is not easy to blister and wrinkle, and is easy to peel.

Description

Technical Field

[0001] The invention relates to the technical field of coating preparation, in particular to a high and low temperature resistant water-based strippable protective coating and a preparation method thereof. Background Art

[0002] Strippable coating is a functional special coating used for temporary protection of substrate surface. During the construction process of large ship-related parts, the construction period is long, and it is inevitable to be contaminated by dust, rain, oil, welding slag, iron filings, etc., which increases the subsequent maintenance cost and wastes manpower, material and financial resources. The traditional solution is to wrap canvas or aluminum foil on the surface of the protected object, but the temporary protection effect is not ideal, and there is still a large amount of cleaning and repair work in the follow-up. At present, more and more solutions for temporary protection using strippable coatings are being adopted. The construction period of large ships is generally more than one year. The adhesion between the strippable coating and the organic primer increases with time, so the strippable coating needs to have complete strippable performance for more than one year. Because general water-based strippable coatings are thermoplastic resin films with poor water resistance, they are prone to blistering, wrinkling and even peeling when exposed to rain, and their water resistance needs to be improved. In actual use, the time span is large, and it needs to experience hot summers and cold winters. Under high temperature conditions, the film of thermoplastic water-based strippable coating becomes soft, and even when the temperature is higher than the glass transition temperature of the coating, the strength of the film decreases, the performance deteriorates, and it is easy to break during the stripping process. In cold winters, especially in the north, below zero degrees, some paint films become more brittle, have no ductility, and are completely unstrippable.

[0003] In many industrial fields, it is often necessary to protect various equipment, workpieces, etc. to prevent them from being eroded and worn by the external environment. Traditional protective coatings often have deficiencies in high and low temperature resistance and are difficult to peel off after use, which brings great difficulties to subsequent maintenance and cleaning. Therefore, it is of great practical significance to develop a high and low temperature resistant, water-based, peelable protective coating. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a high and low temperature resistant water-based peelable protective coating and a preparation method thereof, which solves the problems raised by the above-mentioned background technology.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical scheme: a high and low temperature resistant water-based strippable protective coating, comprising the following components in parts by weight: 30-50 parts of polyurethane emulsion, 20-30 parts of epoxy resin, 20-30 parts of acrylic emulsion, 10-15 parts of polytetrafluoroethylene, 20-30 parts of filler, 10-20 parts of additives, and the balance of water.

[0008] Preferably, the high and low temperature resistant water-based strippable protective coating comprises the following components in parts by weight: 40 parts of polyurethane emulsion, 25 parts of epoxy resin, 25 parts of acrylic emulsion, 13 parts of polytetrafluoroethylene, 25 parts of filler, 15 parts of additives, and the balance of water.

[0009] Preferably, the filler comprises the following components in parts by weight: 4-6 parts of carbon fiber, 4-6 parts of talc powder, 4-6 parts of mica powder, 4-6 parts of bentonite, and 4-6 parts of quartz powder.

[0010] Preferably, the auxiliary agent includes the following components in parts by weight: 2-4 parts of plasticizer, 2-4 parts of dispersant, 2-4 parts of defoamer, 2-4 parts of leveling agent, and 2-4 parts of film-forming auxiliary agent.

[0011] Preferably, the plasticizer is dioctyl phthalate, the dispersant is sodium polyacrylate, the defoamer is a polyether siloxane copolymer, the leveling agent is a polyether modified siloxane, and the film-forming aid is any one or more of dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, and tripropylene glycol n-butyl ether.

[0012] The present invention further discloses a method for preparing a high and low temperature resistant water-based strippable protective coating, comprising the following steps:

[0013] Step 1: Mix polyurethane emulsion, epoxy resin, acrylic emulsion, polytetrafluoroethylene and water, and stir evenly to obtain a mixed solution A;

[0014] Step 2: Add filler to the mixed solution A and continue stirring until it is evenly dispersed to obtain a mixed solution B;

[0015] Step 3: Add an auxiliary agent and a pH adjuster to the mixed solution B, and stir thoroughly to obtain a mixed solution C;

[0016] Step 4: Filter the final mixed solution C to obtain the finished protective coating.

[0017] Preferably, in steps 1 to 3, the stirring speed is 500-1500 rpm, and the stirring time is 30-60 min.

[0018] Preferably, in step 2, the adding time of each filler is 1-3 minutes. After adding, stir for 5-10 minutes before adding the next filler. After adding all the fillers, stir at a speed of 1200-1500 rpm for 20-30 minutes.

[0019] Preferably, in step three, the addition time of each auxiliary agent is 1-3 minutes. After the addition, stir for 5-10 minutes before adding the next auxiliary agent. After all the auxiliary agents are added, stir at a speed of 1200-1500 rpm for 20-30 minutes.

[0020] Preferably, in step three, a pH adjuster is added until the pH of the mixed solution C is 7.3-7.8.

[0021] (III) Beneficial effects

[0022] The present invention provides a high and low temperature resistant water-based peelable protective coating and a preparation method thereof, which has the following beneficial effects:

[0023] 1. This high and low temperature resistant water-based peelable protective coating uses polyurethane emulsion, epoxy resin and acrylic emulsion as the main film-forming substances. Through scientific proportioning and process optimization, the coating has achieved stable performance in a wide temperature range. Polyurethane emulsion gives the coating good flexibility and wear resistance, epoxy resin improves the hardness and adhesion of the coating, and acrylic emulsion enhances the weather resistance and water resistance of the coating. The synergistic effect of the three enables the coating to maintain stable physical and chemical properties in extremely high or low temperature environments, is not easy to bubble or wrinkle, and is easy to peel off.

[0024] 2. Polytetrafluoroethylene is also added to the coating of the present invention. This component has extremely low surface energy, so that the coating can form a smooth film after coating, further improving the water resistance and chemical resistance of the coating. At the same time, the addition of polytetrafluoroethylene also gives the coating excellent self-cleaning properties, which can effectively resist the adhesion of pollutants such as dust and oil, and reduce the subsequent cleaning workload.

[0025] 3. In the selection of fillers, the present invention uses a variety of inorganic materials such as carbon fiber, talcum powder, mica powder, bentonite and quartz powder, which not only have excellent physical and chemical stability, but also can enhance the mechanical strength and wear resistance of the coating. Through reasonable proportioning and dispersion process, these fillers can be evenly dispersed in the coating to form a dense coating structure and improve the overall performance of the coating.

[0026] 4. In terms of the addition of auxiliary agents, the present invention uses a variety of functional auxiliary agents such as plasticizers, dispersants, defoamers, leveling agents and film-forming agents. Each auxiliary agent plays its unique role and jointly improves the comprehensive performance of the coating. The addition of plasticizers such as dioctyl phthalate effectively improves the flexibility and ductility of the coating, making it difficult to soften at high temperatures and difficult to become brittle at low temperatures, thereby ensuring the strippability of the coating. Dispersants such as sodium polyacrylate help various pigments and fillers to be evenly dispersed in the coating, avoid agglomeration, and improve the flatness and aesthetics of the coating. The use of defoamers such as polyether siloxane copolymers effectively eliminates the bubbles generated by the coating during preparation and construction, ensuring the compactness and adhesion of the coating. Leveling agents such as polyether modified siloxanes promote the flow and spreading of the coating, making the coating more uniform and smooth, thereby improving the overall aesthetics of the coating. Film-forming aids such as dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol n-butyl ether, etc., promote the film-forming process of the coating, improve the hardness and wear resistance of the coating, and also help the drying and curing of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the preparation method of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] The embodiment of the present invention provides a high and low temperature resistant water-based strippable protective coating, comprising the following components in parts by weight: 30 parts of polyurethane emulsion, 20 parts of epoxy resin, 20 parts of acrylic emulsion, 10 parts of polytetrafluoroethylene, 20 parts of filler, 10 parts of additives, and the balance of water.

[0031] The filler includes the following components in parts by weight: 4 parts of carbon fiber, 4 parts of talc powder, 4 parts of mica powder, 4 parts of bentonite, and 4 parts of quartz powder.

[0032] Secondly, the additives include the following components in parts by weight: 2 parts of plasticizer, 2 parts of dispersant, 2 parts of defoamer, 2 parts of leveling agent, and 2 parts of film-forming aid; specifically, the plasticizer is dioctyl phthalate, the dispersant is sodium polyacrylate, the defoamer is a polyether siloxane copolymer, the leveling agent is polyether modified siloxane, and the film-forming aid is dipropylene glycol monomethyl ether.

[0033] like Figure 1As shown, the embodiment of the present invention also provides a method for preparing a high and low temperature resistant water-based strippable protective coating, comprising the following steps:

[0034] Step 1: Mix polyurethane emulsion, epoxy resin, acrylic emulsion, polytetrafluoroethylene and water, stir evenly, the stirring speed is 500 rpm, the stirring time is 30 min, and a mixed solution A is obtained;

[0035] Step 2: Add fillers to the mixed solution A. The adding time of each filler is 1 minute. After adding, stir for 5 minutes and then add the next filler. After adding all the fillers, stir at a speed of 1200 rpm for 20 minutes. Continue stirring until uniformly dispersed to obtain a mixed solution B.

[0036] Step 3: Add an auxiliary agent and a pH adjuster to the mixed solution B. The adding time of each auxiliary agent is 1 min. After adding, stir for 5 min and then add the next auxiliary agent. After adding all the auxiliary agents, stir at a speed of 1200 rpm for 20 min. Add a pH adjuster until the pH of the mixed solution C is 7.3 to obtain a mixed solution C.

[0037] Step 4: Filter the final mixed solution C to obtain the finished protective coating.

[0038] Embodiment 2:

[0039] An embodiment of the present invention provides a high and low temperature resistant water-based strippable protective coating, comprising the following components in parts by weight: 40 parts of polyurethane emulsion, 25 parts of epoxy resin, 25 parts of acrylic emulsion, 13 parts of polytetrafluoroethylene, 25 parts of filler, 15 parts of additives, and the balance of water.

[0040] The filler includes the following components in parts by weight: 5 parts of carbon fiber, 5 parts of talc powder, 5 parts of mica powder, 5 parts of bentonite, and 5 parts of quartz powder.

[0041] Secondly, the additives include the following components in parts by weight: 3 parts of plasticizer, 3 parts of dispersant, 3 parts of defoamer, 3 parts of leveling agent, and 3 parts of film-forming aid; specifically, the plasticizer is dioctyl phthalate, the dispersant is sodium polyacrylate, the defoamer is a polyether siloxane copolymer, the leveling agent is polyether modified siloxane, and the film-forming aid is dipropylene glycol monopropyl ether.

[0042] like Figure 1 As shown, the embodiment of the present invention also provides a method for preparing a high and low temperature resistant water-based strippable protective coating, comprising the following steps:

[0043] Step 1: Mix polyurethane emulsion, epoxy resin, acrylic emulsion, polytetrafluoroethylene and water, stir evenly, the stirring speed is 1000 rpm, the stirring time is 45 minutes, and a mixed solution A is obtained;

[0044] Step 2: Add fillers to the mixed solution A. The adding time of each filler is 2 minutes. After adding, stir for 8 minutes and then add the next filler. After adding all the fillers, stir at a speed of 1400 rpm for 25 minutes. Continue stirring until uniformly dispersed to obtain a mixed solution B.

[0045] Step 3: Add an auxiliary agent and a pH adjuster to the mixed solution B. The adding time of each auxiliary agent is 2 minutes. After adding, stir for 8 minutes and then add the next auxiliary agent. After adding all the auxiliary agents, stir at a speed of 1400 rpm for 25 minutes. Add a pH adjuster until the pH of the mixed solution C is 7.5 to obtain a mixed solution C.

[0046] Step 4: Filter the final mixed solution C to obtain the finished protective coating.

[0047] Embodiment three:

[0048] The embodiment of the present invention provides a high and low temperature resistant water-based strippable protective coating, comprising the following components in parts by weight: 50 parts of polyurethane emulsion, 30 parts of epoxy resin, 30 parts of acrylic emulsion, 15 parts of polytetrafluoroethylene, 30 parts of filler, 20 parts of additives, and the balance of water.

[0049] The filler includes the following components in parts by weight: 6 parts of carbon fiber, 6 parts of talcum powder, 6 parts of mica powder, 6 parts of bentonite, and 6 parts of quartz powder.

[0050] Secondly, the additives include the following components in parts by weight: 4 parts of plasticizer, 4 parts of dispersant, 4 parts of defoamer, 4 parts of leveling agent, and 4 parts of film-forming aid; specifically, the plasticizer is dioctyl phthalate, the dispersant is sodium polyacrylate, the defoamer is a polyether siloxane copolymer, the leveling agent is polyether modified siloxane, and the film-forming aid is tripropylene glycol n-butyl ether.

[0051] like Figure 1 As shown, the embodiment of the present invention also provides a method for preparing a high and low temperature resistant water-based strippable protective coating, comprising the following steps:

[0052] Step 1: Mix polyurethane emulsion, epoxy resin, acrylic emulsion, polytetrafluoroethylene and water, stir evenly, the stirring speed is 1500 rpm, the stirring time is 60 min, and a mixed solution A is obtained;

[0053] Step 2: Add fillers to the mixed solution A. The adding time of each filler is 3 minutes. After adding, stir for 10 minutes and then add the next filler. After adding all the fillers, stir at a speed of 1500 rpm for 30 minutes. Continue stirring until uniformly dispersed to obtain a mixed solution B.

[0054] Step 3: Add an auxiliary agent and a pH adjuster to the mixed solution B, the addition time of each auxiliary agent is 3 minutes, stir for 10 minutes after addition, and then add the next auxiliary agent, stir at a speed of 1500 rpm for 30 minutes after adding all the auxiliary agents, and add a pH adjuster until the pH of the mixed solution C is 7.8 to obtain a mixed solution C;

[0055] Step 4: Filter the final mixed solution C to obtain the finished protective coating.

[0056] Comparative Example:

[0057] A high and low temperature resistant water-based strippable protective coating comprises the following components in parts by weight: 30 parts of polyurethane emulsion, 20 parts of epoxy resin, 10 parts of filler, 4 parts of auxiliary agent and the balance of water.

[0058] The filler includes the following components in parts by weight: 5 parts of carbon fiber and 5 parts of talc powder.

[0059] Secondly, the auxiliary agent includes the following components in parts by weight: 2 parts of plasticizer and 2 parts of dispersant; specifically, the plasticizer is dioctyl phthalate, and the dispersant is sodium polyacrylate.

[0060] The preparation method of the high and low temperature resistant water-based strippable protective coating comprises the following steps:

[0061] Step 1: Mix the polyurethane emulsion, epoxy resin and water, stir evenly, the stirring speed is 500 rpm, the stirring time is 30 min, and a mixed solution A is obtained;

[0062] Step 2: Add filler to the mixed solution A, stir at 1200 rpm for 20 min, and continue stirring until uniformly dispersed to obtain mixed solution B;

[0063] Step 3: Add an auxiliary agent and a pH adjuster to the mixed solution B, stir at a speed of 1200 rpm for 20 min, and add a pH adjuster until the pH of the mixed solution C is 7.3 to obtain a mixed solution C;

[0064] Step 4: Filter the final mixed solution C to obtain the finished protective coating.

[0065] Experimental example:

[0066] The protective coatings prepared in Examples 1, 2, 3 and the comparative example were tested for strippability, and the results are shown in the following table:

[0067] Example -20℃ 30 days peelability 30℃ 30 days peelability 60℃30 days peelability Embodiment 1 Complete peeling without residue Complete peeling without residue Complete peeling without residue Embodiment 2 Complete peeling without residue Complete peeling without residue Complete peeling without residue Embodiment 3 Complete peeling without residue Complete peeling without residue Complete peeling without residue Comparative Example The paint film becomes brittle and breaks Not easy to peel off completely The paint film becomes soft and difficult to peel off

[0068] In summary, it can be seen from the test results in the above table that the strippable protective coating provided by the present invention has greatly improved strippability compared to general water-based strippable coatings, and is easy to be completely stripped without residue between -20°C and 60°C, has long-term complete strippability, and is particularly suitable for temporary protection of various metal plate substrate surfaces.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high and low temperature resistant water-based peelable protective coating, characterized in that: The invention comprises the following components in parts by weight: 30-50 parts of polyurethane emulsion, 20-30 parts of epoxy resin, 20-30 parts of acrylic emulsion, 10-15 parts of polytetrafluoroethylene, 20-30 parts of filler, 10-20 parts of auxiliary agent and the balance of water.

2. The high and low temperature resistant water-based peelable protective coating according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 40 parts of polyurethane emulsion, 25 parts of epoxy resin, 25 parts of acrylic emulsion, 13 parts of polytetrafluoroethylene, 25 parts of filler, 15 parts of auxiliary agent and the balance of water.

3. A high and low temperature resistant water-based strippable protective coating according to claim 1 or 2, characterized in that: The filler comprises the following components in parts by weight: 4-6 parts of carbon fiber, 4-6 parts of talc powder, 4-6 parts of mica powder, 4-6 parts of bentonite, and 4-6 parts of quartz powder.

4. A high and low temperature resistant water-based peelable protective coating according to claim 1 or 2, characterized in that: The auxiliary agent comprises the following components in parts by weight: 2-4 parts of plasticizer, 2-4 parts of dispersant, 2-4 parts of defoamer, 2-4 parts of leveling agent and 2-4 parts of film-forming auxiliary agent.

5. The high and low temperature resistant water-based peelable protective coating according to claim 4, characterized in that: The plasticizer is dioctyl phthalate, the dispersant is sodium polyacrylate, the defoamer is a polyether siloxane copolymer, the leveling agent is a polyether modified siloxane, and the film-forming aid is any one or more of dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, and tripropylene glycol n-butyl ether.

6. A method for preparing a high and low temperature resistant water-based strippable protective coating, characterized in that: The following steps are involved: Step 1: Mix polyurethane emulsion, epoxy resin, acrylic emulsion, polytetrafluoroethylene and water, and stir evenly to obtain a mixed solution A; Step 2: Add filler to the mixed solution A and continue stirring until it is evenly dispersed to obtain a mixed solution B; Step 3: Add an auxiliary agent and a pH adjuster to the mixed solution B, stir thoroughly, and obtain a mixed solution C; Step 4: Filter the final mixed solution C to obtain the finished protective coating.

7. A method for preparing a high and low temperature resistant water-based strippable protective coating according to claim 6, characterized in that: In step 1 to step 3, the stirring speed is 500-1500 rpm, and the stirring time is 30-60 min.

8. The method for preparing a high and low temperature resistant water-based strippable protective coating according to claim 7, characterized in that: In step 2, the addition time of each filler is 1-3 minutes. After adding, stir for 5-10 minutes before adding the next filler. After adding all the fillers, stir at a speed of 1200-1500 rpm for 20-30 minutes.

9. The method for preparing a high and low temperature resistant water-based strippable protective coating according to claim 8, characterized in that: In step 3, the addition time of each additive is 1-3 minutes. After adding, stir for 5-10 minutes before adding the next additive. After adding all the additives, stir at a speed of 1200-1500 rpm for 20-30 minutes.

10. The method for preparing a high and low temperature resistant water-based strippable protective coating according to claim 9, characterized in that: In step 3, a pH adjuster is added until the pH of the mixed solution C is 7.3-7.8.

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