Powdered casting coating and preparation and use method thereof

Abstract

The present invention relates to a powdered casting coating comprising, by weight, 0.00 parts of refractory aggregate, 0.1 to 10 parts of a film-forming material, 0.01 to 5 parts of an organic thickener, 0.1 to 10 parts of an inorganic thickener, 0.01 to 2 parts of a quaternary ammonium surfactant, 0.01 to 2 parts of a nonionic surfactant, 0.01 to 5 parts of a dispersant, and 0.01 to 1 part of a solid polysiloxane defoamer. The present invention also discloses methods for preparing and using the powdered casting coating. The powdered casting coating disclosed herein contains no liquid components and is a fully dry powder coating. The preparation process is simple, transportation is convenient, and the cost of using the casting coating is effectively reduced. The powdered casting coating disclosed herein can be mixed with water and mechanically stirred until uniformly mixed before use. It can be prepared and used on-site at any time, facilitating on-site coating management.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a powdered casting coating and a preparation and use method thereof. Background Art

[0002] Foundry coatings are typically sold as finished slurries, which contain 30% to 60% carrier fluid, with water-based coatings containing up to 50% water. For suppliers, slurries present transportation difficulties, while for manufacturers, the increased transportation costs increase the cost of using the coating. Existing dry powder coatings, due to imperfect formulations, offer performance indicators far below the technical standards of finished slurries. Summary of the Invention

[0003] Based on this, it is necessary to provide a powdered casting coating with good comprehensive performance and easy transportation, as well as a preparation and use method thereof, to address the problems of inconvenient transportation and high cost of use of slurry coatings.

[0004] In order to solve the above problems, the present invention adopts the following technical solutions:

[0005] The embodiment of the present invention discloses a powdered casting coating, which includes, by weight, 100 parts of refractory aggregate, 0.1 to 10 parts of film-forming material, 0.01 to 5 parts of organic thickener, 0.1 to 10 parts of inorganic thickener, 0.01 to 2 parts of quaternary ammonium surfactant, 0.01 to 2 parts of nonionic surfactant, 0.01 to 5 parts of dispersant, and 0.01 to 1 part of solid polysiloxane defoamer.

[0006] In one embodiment, the weight ratio of the inorganic thickener to the quaternary ammonium salt surfactant is 5 to 10:1.

[0007] In one embodiment, the film-forming material is a water-soluble resin and / or a redispersible latex powder.

[0008] Furthermore, the particle size of the film-forming material is ≥60 mesh.

[0009] Furthermore, the water-soluble resin is one or more of polyvinyl alcohol, water-based acrylic resin, and water-based phenolic resin.

[0010] Furthermore, the redispersible latex powder is one or more of vinyl acetate-ethylene copolymer latex powder, vinyl acetate-versatate copolymer latex powder, acrylic copolymer latex powder, styrene-butadiene copolymer latex powder, styrene-acrylic acid copolymer latex powder, vinyl acetate latex powder, and acrylic copolymer latex powder.

[0011] In one embodiment, the inorganic thickener is one or more of palygorskite clay, montmorillonite clay, clay, and illite raw powder.

[0012] In one embodiment, the organic thickener includes a hydrophilic organic thickener and a hydrophobically modified organic thickener.

[0013] Furthermore, the hydrophilic organic thickener is cellulose ether.

[0014] Furthermore, the cellulose ether is a delayed solubility cellulose ether and the viscosity of a 1% aqueous solution thereof is 300 to 1000 mPa·s.

[0015] Preferably, the cellulose ether is one or more of methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, methyl hydroxyethyl cellulose, and ethyl hydroxyethyl cellulose.

[0016] Furthermore, the hydrophobically modified organic thickener is one or more of an associative alkali-swellable thickener, a hydrophobically modified polyurethane thickener, a hydrophobically modified amino thickener, and a hydrophobically modified polyurea thickener.

[0017] In one embodiment, the alkyl carbon chain of the quaternary ammonium surfactant has more than 11 carbon atoms to improve the activation effect, and the negative point ion is a chloride ion or a bromide ion.

[0018] Preferably, the quaternary ammonium salt surfactant is one or more of dodecyltributylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, dodecyltributylammonium bromide, dodecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

[0019] In one embodiment, the nonionic surfactant is polyethylene glycol or polypropylene glycol.

[0020] Furthermore, the nonionic surfactant is solid.

[0021] Preferably, the molecular weight of the nonionic surfactant is ≥2000.

[0022] In one embodiment, the dispersant is one or more of maleic acid-acrylic acid copolymer salt, polymethacrylate salt, and succinate block copolymer salt; and the metal ion of the dispersant is sodium, potassium, or ammonium.

[0023] In one embodiment, the refractory aggregate is one or more of zircon powder, mullite, high-alumina bauxite, corundum powder, quartz powder, magnesia powder, forsterite, mica powder, and talc powder.

[0024] In a second aspect, an embodiment of the present invention further discloses a preparation method, which is applied to any of the above-mentioned powdered casting coatings, comprising the following steps:

[0025] Putting refractory aggregate, quaternary ammonium surfactant and nonionic surfactant into a ball mill and grinding them to obtain a mixture;

[0026] The mixed material is evenly mixed with a film-forming material, an organic thickener, an inorganic thickener, a dispersant, and a solid polysiloxane defoamer to obtain the powdery casting coating.

[0027] In a third aspect, an embodiment of the present invention further discloses a method of use, which is applied to any of the above-mentioned powdered casting coatings, comprising the following steps:

[0028] The powdery casting coating is added into water and stirred to obtain a compound, and the compound is applied to an object to be coated.

[0029] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0030] The powdered casting coating disclosed by the present invention has no liquid component in its ingredients and is a fully dry powder coating. The preparation process is simple and the transportation is convenient, and the transportation cost is reduced by 40% to 50%, thereby effectively reducing the use cost of the casting coating.

[0031] The powdered casting coating disclosed by the present invention can be used after being mixed with water and mechanically stirred evenly. It can be prepared and used at any time on site, which is convenient for on-site coating use management.

[0032] The powdered casting coating disclosed in the present invention has good comprehensive performance. After mixing with water, its suspension, coating wear resistance, high-temperature exposure cracking level, shear thinning index and other indicators all reach the level of finished slurry coatings directly configured by suppliers. The surface tension is lower than that of the finished slurry coating, which can better wet the sand mold surface and facilitate the application of the coating. DETAILED DESCRIPTION

[0033] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant examples. Preferred embodiments of the present invention are provided in the examples. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] One of the objects of the present invention is to disclose a powdered foundry coating, which comprises, by weight, 100 parts of refractory aggregate, 0.1 to 10 parts of a film-forming material, 0.01 to 5 parts of an organic thickener, 0.1 to 10 parts of an inorganic thickener, 0.01 to 2 parts of a quaternary ammonium surfactant, 0.01 to 2 parts of a nonionic surfactant, 0.01 to 5 parts of a dispersant, and 0.01 to 1 part of a solid polysiloxane defoamer.

[0036] The powdered casting coating disclosed in the embodiment of the present invention has a refractory aggregate that is a material with an anti-sand sticking effect, thereby preventing the casting from having sand sticking defects. The film-forming material ensures that the refractory aggregate particles can be bonded together to have the strength required by the coating system, and on the other hand, it regulates the fluidity of the coating system. The organic thickener can increase the application viscosity and suspension stability, preventing the refractory aggregate particles from settling. The inorganic thickener can form a structural viscosity, ensure the suspension uniformity of the coating system, and at the same time regulate the rheological properties and thixotropic properties of the coating system. The non-ionic surfactant can improve the wetting performance and application performance of the coating system on the sand mold substrate. The dispersant is combined with the film-forming material to further adjust the fluidity of the coating system, increase the solid content of the coating, and reduce the apparent viscosity of the coating system. The solid polysiloxane defoamer can eliminate bubbles in the coating system and increase the anti-foaming performance of the coating.

[0037] The powdered casting coating disclosed in the embodiment of the present invention uses all solid raw materials, thus avoiding the problem of uniform mixing of liquid materials and belonging to a fully dry powder coating.

[0038] The powdered casting coating disclosed in the embodiment of the present invention has a quaternary ammonium salt surfactant that can activate the gelling properties of an inorganic thickener without applying high-speed shear, and simultaneously has an antiseptic and sterilizing effect. Specifically, the inorganic thickener needs to be under high-speed shear to play a role in forming a colloidal suspension. The present invention uses a quaternary ammonium salt surfactant to activate the inorganic thickener, so that it can quickly swell in a solvent such as water under low-speed stirring to form a three-dimensional network structure without applying high shear. In addition, the quaternary ammonium salt surfactant has an antiseptic and sterilizing effect, so no additional preservative component needs to be added to the coating.

[0039] The powdered casting coating disclosed in the embodiments of the present invention includes an organic thickener and an inorganic thickener to improve thickening efficiency. The organic thickener is a combination of a hydrophilic thickener and a hydrophobically modified thickener, which can reduce the overall viscosity of the water-based system while ensuring good suspension stability. To improve the dissolution and dispersion of the hydrophilic thickener under low-speed stirring, a cellulose ether with delayed solubility is used. The dispersant is a polymer-based hyperdispersant, which effectively reduces the viscosity of the coating system and increases the coating's solids content.

[0040] A second object of the present invention is to disclose a method for preparing the powdered casting coating, comprising the following steps:

[0041] S110, placing 100 parts of refractory aggregate, 0.01-2 parts of quaternary ammonium surfactant, and 0.01-2 parts of nonionic surfactant into a ball mill in sequence, and ball milling for 5-30 minutes to obtain a mixture;

[0042] S120. Place the mixture, 0.1 to 10 parts of a film-forming material, 0.01 to 5 parts of an organic thickener, 0.1 to 10 parts of an inorganic thickener, 0.01 to 5 parts of a dispersant, and 0.01 to 1 part of a solid polysiloxane defoamer into a spiral mixer in sequence, start mixing for 5 to 30 minutes, and obtain the powdered casting coating of the present invention.

[0043] A third object of the present invention is to disclose a method for using the powdered casting coating, comprising the following steps:

[0044] S210, adding water to the mixing tank and starting stirring;

[0045] S220, slowly adding powdered casting coating into the stirring tank and continuously stirring for more than 1 hour to obtain a compound;

[0046] S230, applying the compound to the object to be coated.

[0047] Furthermore, in steps S210 and S220, the stirring speed is ≥80 rpm.

[0048] Furthermore, in steps S210 and S220, the weight ratio of water to powdered casting coating is 1:1-2.

[0049] Example 1

[0050] A powdered casting coating comprises: 1000 kg zircon powder, 20 kg water-based acrylic resin, 1 kg hydroxyethyl cellulose, 4 kg associative alkali-swellable thickener, 30 kg palygorskite clay, 5 kg dodecyltributylammonium bromide, 5 kg polyethylene glycol (PEG2000), 5 kg sodium salt of maleic acid-acrylic acid copolymer, and 5 kg solid polysiloxane defoamer.

[0051] The method for preparing the powdered casting coating of this embodiment comprises the following steps:

[0052] S110, placing 1000 kg of zircon powder, 5 kg of dodecyltributylammonium bromide, and 5 kg of polyethylene glycol (PEG2000) into a ball mill in sequence, and ball milling for 20 minutes to obtain a mixture;

[0053] S120. The mixture prepared in step S110, 20 kg of water-based acrylic resin, 1 kg of hydroxyethyl cellulose, 4 kg of associative alkali-swellable thickener, 30 kg of palygorskite clay, 5 kg of sodium salt of maleic acid-acrylic acid copolymer, and 5 kg of solid polysiloxane defoamer are sequentially placed into a spiral mixer, and mixing is started for 10 minutes to obtain the powdered casting coating of this embodiment.

[0054] Example 2

[0055] A powdered casting coating comprises: 1000 kg of mullite, 60 kg of vinyl acetate-ethylene copolymer latex powder, 1.5 kg of methyl hydroxyethyl cellulose, 3.5 kg of a hydrophobically modified polyurethane thickener, 40 kg of montmorillonite, 5 kg of dodecyltributylammonium chloride, 5 kg of polyethylene glycol (PEG4000), 5 kg of polymethacrylate sodium salt, and 3 kg of a solid polysiloxane defoamer.

[0056] The method for preparing the powdered casting coating of this embodiment comprises the following steps:

[0057] S110, placing 1000 kg of mullite, 5 kg of dodecyltributylammonium chloride, and 5 kg of polyethylene glycol (PEG4000) into a ball mill in sequence, and ball milling for 20 minutes to obtain a mixture;

[0058] S120. The mixture prepared in step S110, 60 kg of vinyl acetate-ethylene copolymer latex powder, 1.5 kg of methyl hydroxyethyl cellulose, 3.5 kg of a hydrophobically modified polyurethane thickener, 40 kg of montmorillonite, 5 kg of sodium polymethacrylate, and 3 kg of a solid polysiloxane defoamer are sequentially placed into a spiral mixer, and mixing is started for 10 minutes to obtain the powdered casting coating of this embodiment.

[0059] Example 3

[0060] A powdery casting coating comprises: 1000 kg of high-alumina bauxite, 20 kg of polyvinyl alcohol, 2 kg of ethyl hydroxyethyl cellulose, 3 kg of a hydrophobically modified amino thickener, 3 parts of 30 kg of montmorillonite, 5 kg of dodecyltributylammonium chloride, 3 kg of polypropylene glycol (PPG2000), 5 kg of sodium polymethacrylate, and 3 kg of a solid polysiloxane defoamer.

[0061] The method for preparing the powdered casting coating of this embodiment comprises the following steps:

[0062] S110, placing 1000 kg of high-alumina bauxite, 5 kg of dodecyltributylammonium chloride, and 3 kg of polypropylene glycol (PPG2000) into a ball mill in sequence, and ball-milling for 20 minutes to obtain a mixture;

[0063] S120. The mixture prepared in step S110, 20 kg of polyvinyl alcohol, 2 kg of ethyl hydroxyethyl cellulose, 3 kg of a hydrophobically modified amino thickener, 30 kg of montmorillonite, 5 kg of sodium polymethacrylate, and 3 kg of a solid polysiloxane defoamer are sequentially placed into a spiral mixer, and the mixing is started for 10 minutes to obtain the powdered casting coating of this embodiment.

[0064] Example 4

[0065] A powdered casting coating comprises: 500 kg of magnesia powder, 500 kg of forsterite, 20 kg of styrene-butadiene copolymer latex powder, 2 kg of methyl hydroxyethyl cellulose, 3 kg of a hydrophobically modified polyurea thickener, 80 kg of illite raw powder, 7 kg of cetyltrimethylammonium bromide, 1.5 kg of polypropylene glycol (PPG4000), 5 kg of potassium salt of succinate block copolymer, and 5 kg of a solid polysiloxane defoamer.

[0066] The method for preparing the powdered casting coating of this embodiment comprises the following steps:

[0067] S110, placing 500 kg of magnesia powder, 500 kg of forsterite, 7 kg of cetyltrimethylammonium bromide, and 1.5 kg of polypropylene glycol (PPG4000) into a ball mill in sequence, and ball milling for 30 minutes to obtain a mixture;

[0068] S120. The mixture prepared in step S110, 20 kg of styrene-butadiene copolymer latex powder, 2 kg of methyl hydroxyethyl cellulose, 3 kg of a hydrophobically modified polyurea thickener, 80 kg of illite raw powder, 5 kg of potassium salt of a succinate block copolymer, and 5 kg of a solid polysiloxane defoamer are sequentially placed into a spiral mixer, and mixing is started for 20 minutes to obtain the powdered casting coating of this embodiment.

[0069] Example 5

[0070] A powdery casting coating comprising:

[0071] 1000kg refractory aggregate, including 300kg zircon powder and 700kg mullite;

[0072] 60kg film-forming material, including 30kg water-based phenolic resin and 30kg acrylic copolymer latex powder;

[0073] 8kg organic thickener, including 2kg hydroxyethyl cellulose, 3kg associative alkali-swellable thickener, and 3kg hydrophobically modified polyurethane thickener;

[0074] 30kg inorganic thickener, including 10kg palygorskite clay, 5kg china clay, and 15kg montmorillonite clay;

[0075] 3.5 kg quaternary ammonium surfactant, including 2 kg dodecyltrimethylammonium chloride and 1.5 kg hexadecyltrimethylammonium chloride;

[0076] 4 kg non-ionic surfactant, including 2 kg polyethylene glycol (PEG2000) and 2 kg polypropylene glycol (PPG2000);

[0077] 8 kg dispersant, including 5 kg potassium salt of polymethacrylate and 3 kg ammonium salt of succinate block copolymer;

[0078] 6kg solid polysiloxane defoamer.

[0079] The method for preparing the powdered casting coating of this embodiment comprises the following steps:

[0080] S110, placing 300 kg of zircon powder, 700 kg of mullite, 2 kg of dodecyltrimethylammonium chloride, 1.5 kg of hexadecyltrimethylammonium chloride, 2 kg of polyethylene glycol (PEG2000), and 2 kg of polypropylene glycol (PPG2000) into a ball mill in sequence, and ball milling for 10 minutes to obtain a mixture;

[0081] S120. The mixture prepared in step S110, 30 kg of water-based phenolic resin, 30 kg of acrylic copolymer latex powder, 2 kg of hydroxyethyl cellulose, 3 kg of associative alkali-swellable thickener, 3 kg of hydrophobically modified polyurethane thickener, 10 kg of palygorskite clay, 5 kg of pottery clay, 15 kg of montmorillonite clay, 5 kg of potassium polymethacrylate, 3 kg of succinate block copolymer ammonium salt, and 6 kg of solid polysiloxane defoamer are sequentially placed into a spiral mixer and mixing is started for 30 minutes to obtain the powdered casting coating of this embodiment.

[0082] The powdered casting coatings described in Examples 1 to 5 were mixed with water at a weight ratio of 1:1 and mechanically stirred for 1 hour to produce composites. The properties of the composites were measured according to JB / T 9226-2008, and the shear thinning index (ratio of apparent viscosity at 6 rpm to apparent viscosity at 60 rpm) and the surface tension of the supernatant were determined. The test results are shown in Table 1. Comparative Example 1 is a mixture of an existing dry powder coating and water, and Comparative Example 2 is a finished, existing slurry-like water-based coating.

[0083] Table 1 Test results

[0084]

[0085]

[0086] The powdered foundry coating and water mixture disclosed in the embodiments of the present invention exhibits superior 24-hour suspension properties, coating wear resistance, high-temperature exposure cracking grade, and shear thinning index to existing dry powder coatings, reaching the level of finished slurry coatings. Furthermore, the surface tension of the powdered foundry coating and water mixture disclosed in the embodiments of the present invention is lower than that of existing dry powder coatings and finished slurry coatings, enabling better wetting of sand mold surfaces and facilitating coating application.

[0087] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A powdery casting coating, characterized in that: The composition comprises, by weight, 100 parts of refractory aggregate, 0.1 to 10 parts of film-forming material, 0.01 to 5 parts of organic thickener, 0.1 to 10 parts of inorganic thickener, 0.01 to 2 parts of quaternary ammonium surfactant, 0.01 to 2 parts of nonionic surfactant, 0.01 to 5 parts of dispersant and 0.01 to 1 part of solid polysiloxane defoamer; The weight ratio of the inorganic thickener to the quaternary ammonium salt surfactant is 5 to 10:1; The film-forming material is a water-soluble resin and / or a redispersible latex powder, wherein the water-soluble resin is one or more of polyvinyl alcohol, water-based acrylic resin, and water-based phenolic resin, and the redispersible latex powder is one or more of vinyl acetate-ethylene copolymer latex powder, acrylic copolymer latex powder, styrene-butadiene copolymer latex powder, styrene-acrylic acid copolymer latex powder, and vinyl acetate latex powder; The inorganic thickener is one or more of palygorskite clay, montmorillonite clay, clay, and illite raw powder; The organic thickener includes a hydrophilic organic thickener and a hydrophobically modified organic thickener, wherein the hydrophilic organic thickener is a cellulose ether, and the hydrophobically modified organic thickener is one or more of an associative alkali-swellable thickener, a hydrophobically modified polyurethane thickener, a hydrophobically modified amino thickener, and a hydrophobically modified polyurea thickener; The quaternary ammonium surfactant has an alkyl carbon chain with more than 11 carbon atoms and a negative ion such as chloride or bromide; The nonionic surfactant is polyethylene glycol or polypropylene glycol; The dispersant is one or more of maleic acid-acrylic acid copolymer salt, polymethacrylate, and succinate block copolymer salt, and the metal ion of the dispersant is sodium, potassium, or ammonium ion.

2. A method for preparing a powdery casting coating according to claim 1, characterized in that: The steps include: Putting refractory aggregate, quaternary ammonium surfactant and nonionic surfactant into a ball mill and grinding them to obtain a mixture; The mixed material is evenly mixed with a film-forming material, an organic thickener, an inorganic thickener, a dispersant, and a solid polysiloxane defoamer to obtain the powdery casting coating.

3. A method for using the powdered casting coating according to claim 1, characterized in that: The steps include: The powdery casting coating is added into water and stirred to obtain a compound, and the compound is applied to an object to be coated.

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