Impact-resistant powder coating composition

Abstract

The invention discloses an impact-resistant powder coating composition, which comprises thermosetting resin, a curing agent and an auxiliary agent, the auxiliary agent comprises an impact-resistant auxiliary agent adopting a core-shell structure, and the core of the impact-resistant auxiliary agent contains not less than 50wt% of cross-linked rubber; on the premise of obviously improving the impact resistance (mainly low-temperature impact resistance) of the powder coating, the weather resistance of the powder coating is not negatively influenced.

Description

Technical Field

[0001] The invention belongs to the field of powder coatings, and in particular relates to an impact-resistant powder coating composition. Background Art

[0002] Thermosetting powder coatings are widely used to replace paints and water-based paints to achieve protective decoration of products in various fields because of their advantages such as green environmental protection, low energy consumption, easy construction and no (or at least very little) VOC emissions. Specifically, the current thermosetting powder coatings (especially weather-resistant thermosetting powder coatings mainly used outdoors) have poor impact resistance and may crack when hit, thereby reducing the protectiveness of the powder coating. The current common solution is to improve the mechanical properties of the coating by adding toughening agents. Commonly used toughening agents include toughening agents with flexible polymer chain structures or toughening agents with core-shell structures; but the use of these toughening agents will lead to poor weather resistance of powder coatings.

[0003] Therefore, the applicant hopes to conduct research and development to solve the above technical problems. Summary of the invention

[0004] In view of this, the object of the present invention is to provide an impact-resistant powder coating composition, which can significantly improve the impact resistance (mainly low-temperature impact resistance) of the powder coating without negatively affecting its weather resistance.

[0005] The technical solution adopted by the present invention is as follows: An impact-resistant powder coating composition comprises a thermosetting resin, a curing agent and an auxiliary agent, wherein the auxiliary agent comprises an impact-resistant auxiliary agent with a core-shell structure, and the core of the impact-resistant auxiliary agent contains no less than 50wt% of cross-linked rubber.

[0006] Preferably, the inner core of the impact-resistant additive contains 85-100 wt % of cross-linked rubber.

[0007] Preferably, the cross-linked rubber comprises silicone-acrylate cross-linked rubber, and the weight proportion of the silicone-acrylate cross-linked rubber to the cross-linked rubber is preferably 50-100wt%, more preferably 65-100wt%, further preferably 80-100wt%, and further preferably 90-100wt%.

[0008] Preferably, the shell of the impact-resistant additive contains not less than 60 wt % of methacrylate, more preferably 70-100 wt %.

[0009] Preferably, the D50 particle size range of the impact-resistant additive is 0.3-0.45 mm, more preferably 0.32-0.42 mm; and / or the D90 particle size range of the impact-resistant additive is 0.65-0.8 mm, more preferably 0.68-0.76 mm.

[0010] Preferably, the sum of the weight parts of the thermosetting resin and the curing agent accounts for 40-80wt% of the weight of the impact-resistant powder coating composition, and more preferably 45-75wt%; and / or the weight part ratio of the thermosetting resin to the impact-resistant powder coating composition is 35-75wt%, and more preferably 40-70wt%.

[0011] Preferably, the weight ratio of the impact-resistant additive to the impact-resistant powder coating composition is 0.1-6 wt %, more preferably 0.5-5 wt %, and further preferably 1-4 wt %.

[0012] Preferably, the thermosetting resin includes polyester resin and / or epoxy resin and / or acrylic resin and / or fluorocarbon resin.

[0013] Preferably, the thermosetting resin is polyester resin, and the curing agent includes triglycidyl isocyanurate (TGIC) and / or hydroxyalkylamide (HAA).

[0014] Preferably, the polyester resin satisfies at least one of the following characteristics: i).. Acid value range is 15-85mgKOH / g, more preferably 20-55mgKOH / g, further preferably 25-45mgKOH / g; ii) a viscosity of 1200-5000 mPa.s at 200°C, more preferably 1500-3500 mPa.s; iii). The glass transition temperature is 45-65°C, more preferably 55-65°C.

[0015] It should be noted that the viscosity value detection standard involved in this application is based on ASTM D 4287-1994, and the detection equipment used can be a standard commercial cone and plate viscometer (for example, ICI cone and plate viscometer (CONE & PLATE), brand CAP 2000 VISCOMETER from Brookfield); the acid value detection standard involved is based on ISO 3682-1998; the glass transition temperature detection standard involved is based on ISO 11357-2-2013; the D50 and D90 particle size data involved are obtained by particle size distribution test using laser diffraction (for example, Malvern Particle Size Analyzer 2000), and the test standard is ISO 13320-2009.

[0016] The present application proposes to use a cross-linked rubber whose core contains not less than 50wt% as an impact-resistant additive for a powder coating composition. After implementation verification, it is found that while the impact resistance of the coating (mainly low-temperature impact resistance) is significantly improved, it will not have a negative impact on its weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a photo of the coating corresponding to Example 1 after the low-temperature impact resistance test. DETAILED DESCRIPTION

[0018] An embodiment of the present application proposes an impact-resistant powder coating composition, comprising a thermosetting resin, a curing agent and an auxiliary agent, wherein the auxiliary agent comprises an impact-resistant auxiliary agent with a core-shell structure, and the inner core of the impact-resistant auxiliary agent contains not less than 50wt% of a cross-linked rubber.

[0019] Preferably, in this embodiment, the inner core of the impact-resistant additive contains 85-100wt% of a cross-linked rubber; further preferably, in this embodiment, the cross-linked rubber includes a silicone-acrylate cross-linked rubber, and the weight ratio of the silicone-acrylate cross-linked rubber to the cross-linked rubber is preferably 50-100wt%, more preferably 65-100wt%, further preferably 80-100wt%, and further preferably 90-100wt%.

[0020] Preferably, in this embodiment, the shell of the impact-resistant additive contains not less than 60 wt % of methacrylate, more preferably 70-100 wt %.

[0021] Preferably, in the present embodiment, the D50 particle size range of the impact-resistant additive is 0.3-0.45 mm, more preferably 0.32-0.42 mm; and / or preferably, in the present embodiment, the D90 particle size range of the impact-resistant additive is 0.65-0.8 mm, more preferably 0.68-0.76 mm.

[0022] Preferably, the impact-resistant additive used in this embodiment can be Metablen S-2501 produced by MITSUBISHIRAYON CO., LTD.; its core contains 100wt% of cross-linked rubber, and its shell contains 100% of methacrylate; its D50 particle size is about 0.37mm, and its D90 particle size is 0.73mm.

[0023] Preferably, in order to further facilitate the achievement of the target technical effect, in this embodiment, the sum of the weight parts of the thermosetting resin and the curing agent accounts for 40-80wt% of the weight of the impact-resistant powder coating composition, and more preferably 45-75wt%; and / or the weight part ratio of the thermosetting resin to the impact-resistant powder coating composition is 35-75wt%, and more preferably 40-70wt%.

[0024] Preferably, in this embodiment, the weight ratio of the impact-resistant additive to the impact-resistant powder coating composition is 0.1-6 wt %, more preferably 0.5-5 wt %, and further preferably 1-4 wt %.

[0025] Preferably, in this embodiment, the thermosetting resin includes polyester resin and / or epoxy resin and / or acrylic resin and / or fluorocarbon resin, and the curing agent can be specifically selected according to the selected thermosetting resin, and this application does not impose a sole limitation during implementation.

[0026] Preferably, in order to further facilitate the achievement of the target technical effect, the thermosetting resin is a polyester resin, and the curing agent includes triglycidyl isocyanurate (TGIC) and / or hydroxyalkylamide (HAA).

[0027] Preferably, in this embodiment, the polyester resin satisfies at least one of the following characteristics: i).. Acid value range is 15-85mgKOH / g, more preferably 20-55mgKOH / g, further preferably 25-45mgKOH / g; ii) a viscosity of 1200-5000 mPa.s at 200°C, more preferably 1500-3500 mPa.s; iii) a glass transition temperature of 45-65°C, more preferably 55-65°C; All kinds of raw materials involved in this application can be directly purchased on the market, and the sources of raw materials are easy to obtain.

[0028] In the specific implementation of the present application, it is also possible to add known leveling agents, degassing agents, antioxidants, dispersants, fillers, pigments, stabilizers, curing accelerators, functional additives and / or other additives to the impact-resistant powder coating composition, which are conventional technical choices of those skilled in the art; specifically, fillers and / or pigments can be selected from carbon black, aluminum hydroxide, barium sulfate, TiO 2 wait.

[0029] When preparing the impact-resistant powder coating composition of the present application, any known preparation process can be used for preparation; preferably, in this embodiment, the impact-resistant powder coating composition is obtained by mixing, melt extrusion, and crushing. Of course, other known preparation processes can also be used to obtain the impact-resistant powder coating composition of this embodiment, and the present application has no particular and unique limitation on its preparation process.

[0030] In order to verify the technical effect of the present application, the present application specifically conducted the following multiple groups of examples as raw materials for powder coating composition formulations for specific test performance comparison: Example 1: An impact-resistant powder coating composition, the raw materials of which include 70wt% of polyester resin, brand GH-3331 provided by Zhejiang Guanghua, the viscosity of which is in the range of 2500-3500mPa.s at 200°C, and the acid value of which is in the range of 32-37 mgKOH / g; 6.4wt% of TGIC, brand HT-702 produced by Huangshan Huahui; 1.5wt% of leveling agent, brand RESIFLOW PV-67C produced by ESTRON; 0.5wt% of degassing agent, specifically benzoin (conventional commercial product); 4wt% of impact-resistant additive, brand Metablen S-2501 produced by MITSUBISHI RAYON CO., LTD. and 17.6wt% of TiO 2 ; The formula raw materials are subjected to the processes of weighing, premixing, melt extrusion, grinding, cyclone separation and the like to prepare an impact-resistant powder coating composition.

[0031] Embodiment 2: The remaining technical solutions of Embodiment 2 are the same as those of Embodiment 1, except that, in Embodiment 2, the weight proportion of the impact-resistant additive is increased to 6wt%, and TiO 2 The weight proportion is reduced to 15.6wt%.

[0032] Embodiment 3: The remaining technical solutions of Embodiment 3 are the same as those of Embodiment 1, except that, in Embodiment 3, the weight proportion of the impact-resistant additive is reduced to 1wt%, and TiO 2 The weight proportion increased to 20.6wt%.

[0033] Embodiment 4: The remaining technical solutions of Embodiment 4 are the same as those of Embodiment 1, except that, in Embodiment 4, the weight proportion of the impact-resistant additive is reduced to 0.5wt%, and TiO 2 The weight proportion increased to 21.1wt%.

[0034] Embodiment 5: The remaining technical solutions of Embodiment 5 are the same as those of Embodiment 1, except that, in Embodiment 5, the weight proportion of the impact-resistant additive is reduced to 0.1wt%, and TiO 2 The weight proportion increased to 21.5wt%.

[0035] Embodiment 6: The remaining technical solutions of Embodiment 6 are the same as those of Embodiment 1, except that, in Embodiment 6, the weight proportion of the impact-resistant additive is reduced to 0.05wt%, and TiO 2 The weight proportion increased to 21.55wt%.

[0036] Example 7: The rest of the technical scheme of Example 7 is the same as that of Example 1, except that, in Example 7, the brand of polyester resin is replaced by ALLNEX's CRYLCOAT® 4642-3, which has a viscosity range of 1500-2300 mPa.s at 200°C and an acid value range of 32-38 mgKOH / g.

[0037] Example 8: The rest of the technical scheme of Example 8 is the same as that of Example 1, except that, in Example 8, the brand of polyester resin is replaced by Crylcoat 2671-3 of ALLNEX, which has a viscosity range of 4300-7300 mPa.s at 200°C and an acid value range of 45-51 mgKOH / g.

[0038] Example 9: The rest of the technical scheme of Example 9 is the same as that of Example 1, except that, in Example 9, TGIC is replaced by alkylamide (HAA), and its brand is Primid® XL-552.

[0039] Comparative Example 1: The remaining technical solutions of this comparative example 1 are the same as those of Example 1, except that: in this comparative example 1, the weight proportion of the impact-resistant additive is reduced to 0wt%, and TiO 2 The weight proportion increased to 21.6wt%.

[0040] Comparative Example 2: The rest of the technical solutions of Comparative Example 2 are the same as those of Example 1, except that in Comparative Example 2, the impact-resistant additive in Example 1 is replaced by GRILTEX ES 502 GRINDING from EMS.

[0041] Comparative Example 3: The rest of the technical solutions of this comparative example 3 are the same as those of Example 1, with the only difference being that in this comparative example 3, the impact-resistant additive in Example 1 is replaced by TS2300 from Tiansong.

[0042] The present application obtains the corresponding powder coating compositions according to the implementation schemes proposed in the above Examples 1-9 and Comparative Examples 1-3.

[0043] The powder coating compositions prepared in Examples 1-9 and Comparative Examples 1-3 were respectively used, and the same aluminum plate was selected as the substrate. The powder coating compositions were cured by baking heating, wherein the heating temperature was 200° C. and the heating time was 12 minutes. Coatings were obtained respectively, and the film thickness of the cured coatings was 60-90 μm. The performance test comparison results are shown in Table 1 below (please refer to Figure 1 Table 1 Performance test comparison of each group of embodiments and comparative examples

[0044]

[0045] After comparative testing, it was found that the powder coating compositions provided in Examples 1-4 & 7-9 have both excellent low-temperature impact resistance and weather resistance.

[0046] It should be noted that the coating performance test involved in this embodiment is carried out according to the test standards described in Table 2 below. Table 2 Test items and test standards

[0047]

[0048] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An impact-resistant powder coating composition, characterized in that: The invention comprises a thermosetting resin, a curing agent and an auxiliary agent, wherein the auxiliary agent comprises an impact-resistant auxiliary agent with a core-shell structure, and the core of the impact-resistant auxiliary agent contains no less than 50wt% of a cross-linked rubber.

2. The impact-resistant powder coating composition according to claim 1, characterized in that: The inner core of the impact-resistant additive contains 85-100 wt % of cross-linked rubber.

3. The impact-resistant powder coating composition according to claim 1 or 2, characterized in that: The cross-linked rubber includes silicone-acrylate cross-linked rubber, and the weight proportion of the silicone-acrylate cross-linked rubber to the cross-linked rubber is preferably 50-100wt%, more preferably 65-100wt%, further preferably 80-100wt%, and further preferably 90-100wt%.

4. The impact-resistant powder coating composition according to claim 1, characterized in that: The shell of the impact-resistant additive contains not less than 60 wt % of methacrylate, more preferably 70-100 wt %.

5. The impact-resistant powder coating composition according to claim 1, characterized in that: The D50 particle size range of the impact-resistant additive is 0.3-0.45 mm, more preferably 0.32-0.42 mm; and / or the D90 particle size range of the impact-resistant additive is 0.65-0.8 mm, more preferably 0.68-0.76 mm.

6. The impact-resistant powder coating composition according to claim 1, characterized in that: The sum of the weight parts of the thermosetting resin and the curing agent accounts for 40-80wt% of the weight part of the impact-resistant powder coating composition, and more preferably 45-75wt%; and / or the weight part of the thermosetting resin accounts for 35-75wt% of the weight part of the impact-resistant powder coating composition, and more preferably 40-70wt%.

7. The impact-resistant powder coating composition according to claim 1 or 6, characterized in that: The weight proportion of the impact-resistant additive to the impact-resistant powder coating composition is 0.1-6 wt %, more preferably 0.5-5 wt %, and further preferably 1-4 wt %.

8. The impact-resistant powder coating composition according to claim 1, characterized in that: The thermosetting resin includes polyester resin and / or epoxy resin and / or acrylic resin and / or fluorocarbon resin.

9. The impact-resistant powder coating composition according to claim 1, characterized in that: The thermosetting resin is polyester resin, and the curing agent includes triglycidyl isocyanurate (TGIC) and / or hydroxyalkylamide (HAA).

10. The impact-resistant powder coating composition according to claim 9, characterized in that: The polyester resin meets at least one of the following characteristics: i) Acid value range is 15-85mgKOH / g, more preferably 20-55mgKOH / g, further preferably 25-45mgKOH / g; ii) a viscosity of 1200-5000 mPa.s at 200°C, more preferably 1500-3500 mPa.s; iii). The glass transition temperature is 45-65°C, more preferably 55-65°C.

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