High-temperature-resistant strippable coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of coatings, and provides a high-temperature-resistant strippable coating as well as a preparation method and application thereof. The high-temperature-resistant strippable coating provided by the invention adopts thermoplastic elastic polyurethane resin, water-based self-crosslinking acrylic resin and water as main components, the glass-transition temperature of the thermoplastic elastic polyurethane resin is 0-15 DEG C, and the glass-transition temperature of the water-based self-crosslinking acrylic resin is 30-60 DEG C; the mass ratio of the thermoplastic elastic polyurethane resin to the water-based self-crosslinking acrylic resin is (1-3): 1. The high-temperature-resistant strippable coating provided by the invention is easy to strip after forming a film, the coating has relatively high tensile strength and tearing strength, is not easy to tear into small fragments, is suitable for various different materials, does not damage or influence the coated surface, and has a good application prospect. The film can be formed at room temperature and at high temperature (such as baking and heating at the temperature of more than or equal to 130 DEG C), and the coating film obtained by any film forming mode has excellent peelability.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and more specifically, to a high-temperature resistant peelable coating and its preparation method and application. Background Art

[0002] Most high-value-added commodities require temporary protection during storage and transportation. There are various solutions for the flat parts of commodities (such as wrapping with plastic protective films, etc.), but for irregular surfaces, the protection means are relatively limited, with low efficiency and high costs. In addition, for some commodities that need to be partially protected during multiple processes of production and processing, the options for protection schemes are limited. Currently, manual protection is mostly used, but this method has low efficiency and high costs.

[0003] The peelable protective coating is applied to the surface of the article to be protected. After drying, it can form a coating with a certain protective effect, which can protect the commodity, preventing the surface from being scratched, contaminated by dust and rain during transportation and storage, and can also protect the local or all parts of the commodity during multiple processes of production and processing. It can protect both the flat part and the shaped part of the commodity, and at the same time will not cause any damage to the commodity, and can be easily peeled off. After use, it is easy to remove. This kind of temporary protection material is convenient to use, has high efficiency, and a wide range of application scenarios. However, most of the currently commercially available peelable protective coatings can only be used at room temperature and will fail at high temperatures (such as ≥130°C) during operation, resulting in inability to peel off, and cannot meet the protection requirements of some articles that need to be processed at higher temperatures in post-processing.

[0004] Therefore, there is an urgent need to develop a high-temperature resistant and peelable coating that can be used both in a room temperature environment and in a high-temperature environment, and can provide temporary protection for articles of different materials. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above prior art. For this purpose, the present invention provides a high-temperature resistant peelable coating and its preparation method and application. The high-temperature resistant peelable coating provided by the present invention can form a film at room temperature and can also be baked into a film (the baking temperature can be ≥130°C). It is easy to construct, can be mechanically constructed industrially, has high efficiency, low cost, can be applied to the surfaces of various materials (such as metals, plastics, glasses, ceramics, and coatings, etc.) and play a temporary protection role, has no influence on the articles to be protected, is easy to peel off later, and is environmentally friendly.

[0006] The first aspect of the present invention provides a high-temperature resistant peelable coating.

[0007] Specifically, a high-temperature resistant peelable coating comprises the following components:

[0008] Thermoplastic elastic polyurethane resin

[0009] Waterborne self-crosslinking acrylic resin

[0010] Water;

[0011] The glass transition temperature of the thermoplastic elastomeric polyurethane resin is 0 - 15°C;

[0012] The glass transition temperature of the waterborne self-crosslinking acrylic resin is 30 - 60°C;

[0013] The mass ratio of the thermoplastic elastomeric polyurethane resin to the waterborne self-crosslinking acrylic resin is (1 - 3):1.

[0014] The present invention utilizes a combination of a thermoplastic elastomeric polyurethane resin and a waterborne self-crosslinking acrylic resin in a specific ratio. The glass transition temperature (Tg) of the thermoplastic elastomeric polyurethane resin is low, while that of the waterborne self-crosslinking acrylic resin is high. When used in combination in a specific ratio, it can not only ensure that the coating film is easily torn off, but also ensure that the coating film has a certain tensile strength and is not easily torn into small pieces, improving the peelability of the coating. At the same time, it has high-temperature resistance and can still maintain the same characteristics after high-temperature baking, and can be easily peeled off from the surface of the article, meeting the requirements for use at room temperature and at high temperature. If the elastomeric thermoplastic urethane resin with a low Tg is used alone or in excessive amounts, after film formation at room temperature, the tensile strength is low, it is fragile during peeling, and the peelability is poor. After baking film formation, it is not easily peeled off from the substrate. If the waterborne self-crosslinking acrylic resin with a high Tg is used alone or in excessive amounts, it is not easily film-formed at room temperature and cannot be peeled off. After baking film formation, the paint film is too brittle and still cannot be peeled off.

[0015] Preferably, by weight, the high-temperature resistant peelable coating comprises the following components:

[0016] Thermoplastic elastomeric polyurethane resin 25 - 50 parts

[0017] Waterborne self-crosslinking acrylic resin 15 - 30 parts

[0018] Water 10 - 30 parts.

[0019] Preferably, the glass transition temperature of the thermoplastic elastomeric polyurethane resin is 5 - 10°C, and / or the glass transition temperature of the waterborne self-crosslinking acrylic resin is 30 - 50°C.

[0020] More preferably, the glass transition temperature of the thermoplastic elastomeric polyurethane resin is 6 - 10°C, and / or the glass transition temperature of the waterborne self-crosslinking acrylic resin is 33 - 45°C.

[0021] Preferably, the thermoplastic elastic polyurethane resin is at least one of the thermoplastic elastic polyurethane resin with model number A089 produced by Guangzhou Haoyi New Material Technology Co., Ltd., the thermoplastic elastic polyurethane resin with model number B1103 produced by Bayer, and the thermoplastic elastic polyurethane resin with model number Wb2349 produced by Wanhua.

[0022] Preferably, the waterborne self-crosslinking acrylic resin is the waterborne self-crosslinking acrylic resin with model number 139 produced by Badfu and / or the waterborne self-crosslinking acrylic resin with model number B358 produced by Baolijia.

[0023] Preferably, the mass ratio of the thermoplastic elastic polyurethane resin to the waterborne self-crosslinking acrylic resin is (2 - 3):1.

[0024] Preferably, the high-temperature peelable coating further comprises additives, and the additives include at least one of a wetting agent, a film-forming aid, an aqueous color paste, and a thickener.

[0025] More preferably, by weight, the additives comprise the following components:

[0026]

[0027] Even more preferably, by weight, the additives comprise the following components:

[0028]

[0029] Preferably, the wetting agent is the wetting agent with model number TEGO 245 produced by Degussa and / or the wetting agent with model number BYK 333 produced by BYK Chemie GmbH.

[0030] Preferably, the film-forming aid is the film-forming aid with model number alcohol ester 12 produced by Eastman Chemical Company and / or the film-forming aid with model number CL3101 produced by Solvay.

[0031] Preferably, the aqueous color paste is the aqueous color paste with model number Cody Sc series produced by Cody and / or the special color paste for waterborne industrial paints produced by Shiming.

[0032] Preferably, the thickener is the thickener with model number Borchers 0625 produced by Milliken and / or the thickener with model number Mingling PRU45 produced by Mingling Chemie GmbH.

[0033] Preferably, the film-forming temperature of the high-temperature resistant strippable coating is 15 - 220 °C, and / or the film-forming time of the high-temperature resistant strippable coating is 5 - 40 min. The high-temperature resistant strippable coating provided by the present invention can form a film at room temperature or at high temperature (such as baking and heating at 50 - 220 °C). Whether it forms a film at low temperature or high temperature, it does not affect the excellent strippable performance of the coating.

[0034] More preferably, the film-forming temperature of the high-temperature resistant strippable coating is 20 - 190 °C, and / or the film-forming time of the high-temperature resistant strippable coating is 10 - 30 min.

[0035] Even more preferably, the film-forming temperature of the high-temperature resistant strippable coating is 50 - 190 °C, and / or the film-forming time of the high-temperature resistant strippable coating is 20 - 30 min.

[0036] The second aspect of the present invention provides a preparation method of a high-temperature resistant strippable coating.

[0037] A preparation method of a high-temperature resistant strippable coating includes the following steps:

[0038] Mix each component to obtain the high-temperature resistant strippable coating.

[0039] Preferably, mix each component while stirring.

[0040] The third aspect of the present invention provides an application of a high-temperature resistant strippable coating.

[0041] An application of a high-temperature resistant strippable coating in the temporary protection of glass, metal, ceramic, plastic, cement or coating surface.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] The high-temperature resistant peelable coating provided by the present invention uses thermoplastic elastic polyurethane resin, waterborne self-crosslinking acrylic resin and water as the main components. The glass transition temperature of the thermoplastic elastic polyurethane resin used is 0-15°C, and the glass transition temperature of the waterborne self-crosslinking acrylic resin is 30-60°C. The mass ratio of the thermoplastic elastic polyurethane resin to the waterborne self-crosslinking acrylic resin is (1-3):1. The high-temperature resistant peelable coating provided by the present invention can form a film at room temperature or at high temperature (such as baking and heating at ≥130°C to form a film). Moreover, it is easy to peel off after film formation. No matter which film-forming method is used, it does not affect the peelable performance of the coating. The obtained coating has a certain tensile strength and is not easily torn into small pieces. It has high-temperature resistance. The high-temperature resistant peelable coating of the present invention can be further coated on the surface of an article to play a temporary protection role (such as dust prevention, waterproofing, anti-impact, etc.), and is applicable to surfaces of various materials and different shapes (such as metal, plastic, glass, ceramic and coating surfaces, etc., which can be flat surfaces or other shaped surfaces, and even applicable to the surfaces of irregular articles). It can be peeled off at any time after film formation without affecting the protected article. It is convenient to use. Just add clear water to brush or spray. It is convenient to use. It can be constructed manually or can also be applied to industrial automatic spraying or dipping. After the high-temperature resistant peelable coating provided by the present invention forms a film, it can also be applied to the process of multiple spraying and multiple baking, and its peelable performance is not affected, which is also a performance that currently commercially available products cannot achieve. This product is non-toxic and environmentally friendly, does not contain heavy metals, halogens, aromatic hydrocarbons and organotin, and meets the requirements of the US FDA standard and the EU RoHS. Detailed Embodiments

[0044] In order to make those skilled in the art more clearly understand the technical solutions described in the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0045] The raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions.

[0046] The raw materials involved in the examples and comparative examples of the present invention:

[0047] Thermoplastic elastic polyurethane resin: The thermoplastic elastic polyurethane resin with the model number A089 produced by Guangzhou Haoyi New Material Technology Co., Ltd., and the glass transition temperature is 6°C.

[0048] Waterborne self-crosslinking acrylic resin: The waterborne self-crosslinking acrylic resin with the model number 139 produced by Badfu, and the glass transition temperature is 33°C.

[0049] Waterborne polyurethane emulsion: Produced by Guangzhou Guanzhi New Material Company, model number 3168.

[0050] Waterborne styrene-modified acrylic resin: Produced by Badfu Co., Ltd., model number 366.

[0051] Wetting agent: Produced by Degussa Co., Ltd., model number TEGO 245.

[0052] Film-forming aid: Alcohol ester 12 produced by Eastman Co., Ltd.

[0053] Waterborne color paste: Special color paste for Shiming waterborne industrial paint.

[0054] Thickener: Produced by Münzing Co., Ltd., model number PRU45.

[0055] Example 1

[0056] A high-temperature resistant peelable coating, by weight, comprises the following components (Table 1):

[0057]

[0058] The preparation method of the above high-temperature resistant peelable coating comprises the following steps:

[0059] Weigh each component, add each component while stirring, and after stirring evenly, a high-temperature resistant peelable coating is prepared.

[0060] Examples 2 - 4

[0061] Examples 2 - 4 provide high-temperature resistant peelable coatings, which are different from Example 1 in that the components and their dosages are different, as shown in Table 1 below. The preparation methods are the same as those in Example 1.

[0062] Comparative Example 1

[0063] A coating, which is different from Example 1 in that the ratio of thermoplastic elastomeric polyurethane resin to waterborne self-crosslinking acrylic resin is different, as shown in Table 1 below.

[0064] Comparative Example 2

[0065] A coating, which is different from Example 1 in that the ratio of thermoplastic elastomeric polyurethane resin to waterborne self-crosslinking acrylic resin is different, as shown in Table 1 below.

[0066] Comparative Example 3 (without thermoplastic elastomeric polyurethane resin)

[0067] A coating, which is different from Example 1 in that the thermoplastic elastomeric polyurethane resin is replaced with an equal amount of waterborne polyurethane emulsion.

[0068] Comparative Example 4 (without waterborne self-crosslinking acrylic resin)

[0069] A coating, which is different from Example 1 in that the waterborne self-crosslinking acrylic resin is replaced with an equal amount of waterborne styrene-modified acrylic resin.

[0070] Comparative Example 5 (raising the Tg of thermoplastic elastomeric polyurethane resin)

[0071] A coating, which is different from Example 1 in that the thermoplastic elastomeric polyurethane resin is replaced with a thermoplastic elastomeric polyurethane resin having a glass transition temperature of 20 °C.

[0072] Comparative Example 6 (lowering the Tg of thermoplastic elastomeric polyurethane resin)

[0073] A coating, which is different from Example 1 in that the thermoplastic elastomeric polyurethane resin is replaced with a thermoplastic elastomeric polyurethane resin having a glass transition temperature of -5 °C.

[0074] Comparative Example 7 (lowering the Tg of waterborne self-crosslinking acrylic resin)

[0075] A coating, which is different from Example 1 in that the waterborne self-crosslinking acrylic resin is replaced with a waterborne self-crosslinking acrylic resin having a glass transition temperature of 25 °C.

[0076] Comparative Example 8 (raising the Tg of waterborne self-crosslinking acrylic resin)

[0077] A coating, which is different from Example 1 in that the waterborne self-crosslinking acrylic resin is replaced with a waterborne self-crosslinking acrylic resin having a glass transition temperature of 65 °C.

[0078] The raw materials and dosages of each example and each comparative example are as follows:

[0079] Table 1 Components and Dosages (parts by weight) of Each Example and Comparative Example

[0080]

[0081]

[0082] Product Effect Test

[0083] 1. Test Method

[0084] (1) Peelability: The coating is applied to the surface of the article to be protected. After film formation, the film layer is scratched with a utility knife and then torn off by hand. Then, it is classified according to the ease of tearing, divided into 0-5 levels, a total of 6 levels;

[0085] Level 5 indicates that the film layer can be easily peeled off as a whole and the film layer is not easily broken;

[0086] Level 4 indicates that the film layer can be easily peeled off and can be peeled off in large pieces;

[0087] Level 3 indicates that the film layer can be peeled off relatively easily and there will be small fragments in the film layer;

[0088] Level 2 indicates that the film layer is difficult to peel off and the film layer is all small fragments;

[0089] Level 1 indicates that the film layer is difficult to peel off and the ones that can be peeled off are all small fragments;

[0090] Level 0 indicates that the film layer cannot be peeled off.

[0091] According to the above method, the air-drying strippability, one-time baking strippability (50°C * 30 min or 180°C * 20 min), two-time baking strippability (first bake at 130°C * 20 min, and then bake at 190°C * 20 min), and strippability after standing at room temperature for 15 days of each coating were tested respectively.

[0092] (2) Tensile strength: GB / T 1040 "Determination of Tensile Properties of Plastics".

[0093] (3) Tear strength: GB / T 16777-2008 "Test Methods for Building Waterproof Coatings".

[0094] (4) FDA test: Article 21 of the US Food and Drug Administration, "Food and Drugs", USA FDA21.

[0095] (5) ROHs test: EU 2011 / 65 / EU, "Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment" (Restriction of Hazardous Substances), usually abbreviated as RoHS2 Directive.

[0096] (6) Water resistance: GB / T 1733-1993 "Method for Determining Water Resistance of Paint Films".

[0097] (7) Construction performance: GB / T 6753.6—1986 "Large Area Brushing Test of Coating Products".

[0098] The performance of the coatings of each example and comparative example was tested on different substrate surfaces of glass substrates, stainless steel substrates, ABS plastic substrates (ABS is a terpolymer of three monomers: acrylonitrile (A), butadiene (B), and styrene (S)), and baking paint coatings (simulating multi-process complex protection processes).

[0099] 2. Test results

[0100] Table 2 Test results of each example and each comparative example (on glass substrates)

[0101]

[0102]

[0103] Table 3 Test results of each example and each comparative example (on stainless steel substrates)

[0104]

[0105]

[0106] Table 4 Test Results of Each Example and Each Comparative Example (on ABS Plastic Substrate)

[0107]

[0108] Table 5 Test Results of Each Example and Each Comparative Example (on Baked Paint Coating, Simulating Multi - process Complex Protection Process)

[0109]

[0110]

[0111] Note: "Baked paint coating" refers to the coating obtained by spraying water - soluble amino baked paint on a glass substrate, baking at 170 °C for 20 min, and then cooling.

[0112] As can be seen from the above Tables 2 - 5, the coatings of Examples 1 - 4 have excellent application properties, good water resistance (the coating shows no change for at least 6 - 12 hours in the water resistance test), high tensile strength (up to 2.45 - 2.6 MPa) and tear strength (15 - 18 N / mm), can be peeled off after film - forming and are not easily torn into small pieces, have excellent peelability, and have excellent performance when used on different substrate surfaces (glass substrate, stainless - steel substrate, ABS plastic substrate, baked paint coating) (the peelability can reach Grade 4 - 5), have a wide range of applications, and both the FDA detection and the FDA detection results are qualified, and are environmentally friendly. In addition, whether the coating is air - dried, baked - dried, or baked twice (130 °C * 20 min + 190 °C * 20 min), or left at room temperature for 15 days, the peelability of the coating basically does not decrease, indicating that the coating has good high - temperature resistance and a wide usable temperature range, can be used both at room temperature and at high temperature without affecting the performance of the coating, thus broadening the application scenarios of the coating.

[0113] Compared with Example 1, in Comparative Example 1, due to the lower amount of thermoplastic elastomeric polyurethane resin than the water - borne self - crosslinking acrylic resin, the tensile strength and tear strength decreased, and the peelability became worse.

[0114] Compared with Example 1, in Comparative Example 2, due to the excessive amount of thermoplastic elastomeric polyurethane resin, the tensile strength and tear strength decreased, and the peelability became worse.

[0115] Compared with Example 1, in Comparative Example 3, the thermoplastic elastomeric polyurethane resin was replaced with an aqueous polyurethane emulsion in equal amounts (i.e., without thermoplastic elastomeric polyurethane resin), in Comparative Example 4, the waterborne self-crosslinking acrylic resin was replaced with a waterborne styrene-modified acrylic resin in equal amounts (i.e., without waterborne self-crosslinking acrylic resin), in Comparative Example 5, the Tg of the thermoplastic elastomeric polyurethane resin was increased, in Comparative Example 6, the Tg of the thermoplastic elastomeric polyurethane resin was decreased, in Comparative Example 7, a self-crosslinking acrylic resin with a lower Tg was used, and in Comparative Example 8, the Tg of the waterborne self-crosslinking acrylic resin was increased. All of the above led to a decrease in the tensile strength and tear strength of the resulting coating film, and the peelability became poor. In particular, the coating film obtained by baking might even fail and did not have peelability.

Claims

1. A high temperature resistant peelable coating, characterized in that: The components include: Thermoplastic elastic polyurethane resin Waterborne self-crosslinking acrylic resin water; The glass transition temperature of the thermoplastic elastic polyurethane resin is 0-15°C; The glass transition temperature of the water-based self-crosslinking acrylic resin is 30-60°C; The mass ratio of the thermoplastic elastic polyurethane resin to the water-based self-crosslinking acrylic resin is (1-3):

1.

2. The high temperature resistant peelable coating according to claim 1, characterized in that: The high temperature resistant strippable coating comprises the following components in parts by weight: Thermoplastic elastic polyurethane resin 25-50 parts 15-30 parts of water-based self-crosslinking acrylic resin 10-30 parts of water.

3. The high temperature resistant peelable coating according to claim 1, characterized in that: The glass transition temperature of the thermoplastic elastic polyurethane resin is 5-10°C, and / or the glass transition temperature of the water-based self-crosslinking acrylic resin is 30-50°C.

4. The high temperature resistant peelable coating according to claim 1, characterized in that: The mass ratio of the thermoplastic elastic polyurethane resin to the water-based self-crosslinking acrylic resin is (2-3):

1.

5. The high temperature resistant peelable coating according to claim 1, characterized in that: The thermoplastic elastic polyurethane resin is at least one of the thermoplastic elastic polyurethane resin with model number A089 produced by Guangzhou Haoyi New Materials Technology Co., Ltd., the thermoplastic elastic polyurethane resin with model number B1103 produced by Bayer, and the thermoplastic elastic polyurethane resin with model number Wb2349 produced by Wanhua, and / or the water-based self-cross-linking acrylic resin is the water-based self-cross-linking acrylic resin with model number 139 produced by Badfu and / or the water-based self-cross-linking acrylic resin with model number B358 produced by Baoliga.

6. The high temperature resistant peelable coating according to claim 1, characterized in that: The high temperature resistant strippable coating also includes an auxiliary agent, and the auxiliary agent includes at least one of a wetting agent, a film-forming auxiliary agent, a water-based color paste, and a thickener.

7. The high temperature resistant peelable coating according to claim 6, characterized in that: In parts by weight, the auxiliary agent includes the following components:

8. The high temperature resistant peelable coating according to claim 1, characterized in that: The film-forming temperature of the high-temperature resistant strippable coating is 15-220° C., and / or the film-forming time of the high-temperature resistant strippable coating is 5-40 minutes.

9. The method for preparing the high temperature resistant strippable coating according to any one of claims 1 to 8, characterized in that: The steps include: The components are mixed to prepare the high temperature resistant strippable coating.

10. Use of the high temperature resistant strippable coating according to any one of claims 1 to 8 in temporary protection of glass, metal, ceramic, plastic, cement or coating surfaces.

Images