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CN-121975387-A - Airtight coating for granary and preparation method thereof

CN121975387ACN 121975387 ACN121975387 ACN 121975387ACN-121975387-A

Abstract

The application relates to the technical field of coatings, and provides an airtight coating for a granary and a preparation method thereof. The airtight coating for the granary comprises, by mass, 40-50 parts of acrylic emulsion, 0.2-0.45 part of layered barrier material, 4-7 parts of cross-linking agent, 3-12 parts of auxiliary agent, and the balance of deionized water, wherein the balance is up to 100 parts. The application not only endows the granary with better initial air tightness by the combined action of the acrylic emulsion with the core-shell structure, the layered barrier material, the cross-linking agent and the like, but also can maintain more stable sealing performance under the long-term grain storage working condition of the granary, and simultaneously has the performances of crack resistance, adhesion, damp heat resistance and the like.

Inventors

  • Nie huang
  • ZHENG DONGYANG
  • PAN TAO

Assignees

  • 河南聚恒新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260303

Claims (10)

  1. 1. The airtight coating for the granary is characterized by comprising the following components in parts by mass: 40-50 parts of acrylic emulsion, 0.2 To 0.45 parts of lamellar barrier material, 4-7 Parts of cross-linking agent, 3-12 Parts of auxiliary agent, Deionized water, the balance being added to 100 parts; The acrylic emulsion comprises an acrylic emulsion with a core-shell structure, and comprises a core layer, an inner shell layer and an outer shell layer, wherein the core layer comprises butyl acrylate, isooctyl acrylate and acrylic acid, the inner shell layer comprises methyl methacrylate and acrylic acid, and the outer shell layer comprises styrene, methyl methacrylate and methacrylic acid; The mass ratio of the core layer, the inner shell layer and the outer shell layer is (2.5-6.5): 1-3.5): 1.
  2. 2. The airtight coating for a grain bin according to claim 1, wherein, The mass ratio of the butyl acrylate, the isooctyl acrylate and the acrylic acid in the core layer is 1 (0.1-0.3): 0.001-0.015% The mass ratio of the methyl methacrylate to the acrylic acid in the inner shell layer is 1 (0.06-0.25), and/or In the outer shell layer, the mass ratio of the styrene to the methyl methacrylate to the methacrylic acid is1 (0.9-1) to 0.1-0.2.
  3. 3. The airtight coating for a grain bin according to claim 1, wherein, The layered barrier material comprises graphene oxide, and/or The crosslinking agent comprises carbodiimide crosslinking agent and aqueous polyurethane crosslinking agent, and/or The auxiliary agent comprises a dispersing agent, a defoaming agent, a film forming agent, a preservative, a leveling agent and a pH regulator.
  4. 4. The airtight coating for barn according to claim 3, wherein, The mass ratio of the carbodiimide crosslinking agent to the aqueous polyurethane crosslinking agent in the crosslinking agent is (1.5-3): 1, and/or In the auxiliary agent, the mass ratio of the dispersing agent to the defoaming agent to the film forming agent to the preservative to the leveling agent to the pH regulator is 1 (0.2-2), 1 (10) to 0.2-2 to 1.5-14 to 0.05-0.85.
  5. 5. A process for preparing a grain-barrier coating according to any one of claims 1 to 4, comprising the steps of: s100, preparing the acrylic emulsion; s200, adding the layered barrier material into deionized water for dispersion treatment, and adjusting pH to obtain layered barrier material dispersion liquid; S300, carrying out first stirring treatment on the acrylic emulsion, and adding the layered barrier material dispersion liquid, the auxiliary agent and the cross-linking agent in the process of the first stirring treatment to obtain the airtight coating for the granary; The acrylic emulsion comprises an acrylic emulsion with a core-shell structure, and comprises a core layer, an inner shell layer and an outer shell layer, wherein the core layer comprises butyl acrylate, isooctyl acrylate and acrylic acid, the inner shell layer comprises methyl methacrylate and acrylic acid, and the outer shell layer comprises styrene, methyl methacrylate and methacrylic acid; The mass ratio of the core layer, the inner shell layer and the outer shell layer is (2.5-6.5): 1-3.5): 1.
  6. 6. The method of producing the acrylic emulsion according to claim 5, comprising the steps of: s110, after mixing the butyl acrylate, the isooctyl acrylate and the acrylic acid, adding a first part of core layer initiator and a first part of core layer emulsifier, and performing first shearing treatment to obtain core layer pre-emulsion; S120, adding a second part of the core layer initiator and a second part of the core layer emulsifier into deionized water, and then adding the core layer pre-emulsion to perform first heat preservation treatment to obtain core layer emulsion; S130, mixing the methyl methacrylate and the acrylic acid, adding an inner shell layer initiator, and performing second heat preservation treatment to obtain an inner shell layer emulsion; S140, adding the inner shell emulsion into the core layer emulsion, and performing third heat preservation treatment to obtain an intermediate emulsion; S150, after dissolving a shell layer emulsifier in deionized water, adding a mixture of the styrene, the methyl methacrylate and the methacrylic acid, and performing second shearing treatment to obtain a shell layer emulsion; S160, dripping the shell emulsion into the intermediate emulsion, performing fourth heat preservation treatment, and adjusting pH to obtain the acrylic emulsion.
  7. 7. The method according to claim 6, wherein, The mass ratio of the first part of the core layer initiator to the second part of the core layer initiator is 1 (1.8-2.2), and/or The mass ratio of the first part of the core layer emulsifier to the second part of the core layer emulsifier is 1 (1-1.1), and/or The temperature of the first heat preservation treatment is 75-80℃, and/or The first heat-preserving treatment is carried out for 1-2h, and/or The temperature of the second heat preservation treatment is 80-85℃, and/or The second heat preservation treatment time is 2-3h, and/or The temperature of the third heat preservation treatment is 80-85℃, and/or The time of the third heat preservation treatment is 1-2h, and/or The temperature of the fourth heat preservation treatment is 80-85℃, and/or The fourth heat preservation treatment time is 1.5-2h, and/or The pH was adjusted to 7-8.
  8. 8. The method according to claim 5, wherein in S200, The solid content of the layered barrier material dispersion is 1-3%, and/or Said pH is adjusted to 7-8.5, and/or The dispersing treatment time is 10-20min.
  9. 9. The method according to claim 5, wherein S200 further comprises: s210, adding an interfacial activator into the layered barrier material dispersion liquid to carry out second stirring treatment for 20-40min; Wherein the interfacial activator comprises a silane coupling agent.
  10. 10. The method according to claim 5, wherein in S300, The rotational speed of the first stirring treatment is 300-500rpm, and/or the pH of the airtight coating for the granary is 7.5-8.5.

Description

Airtight coating for granary and preparation method thereof Technical Field The application relates to the technical field of coatings, in particular to an airtight coating for a granary and a preparation method thereof. Background The granary (including a flat granary, a shallow circular granary, a vertical granary and matched granary tops, granary walls, terraces, expansion joints, wall penetrating pipelines and the like) is generally required to realize high-level air tightness in the grain storage process so as to meet the operation requirements of low-oxygen grain storage, nitrogen, carbon dioxide air conditioning, phosphine fumigation and the like, reduce the risk of worm and mildew and reduce the consumption of medicaments or inert gases. In addition to relying on structural sealing (door and window, valve member and wall-penetrating part sealing), the existing granary airtight measures also often adopt coating type sealing materials to seal the surfaces of concrete, mortar or metal base materials so as to reduce gas permeation caused by base material pores and cracks. At present, the coating type sealing material for the granary mostly adopts an organic polymer film forming system (such as acrylic acid, polyurethane, epoxy or a composite system thereof) to be matched with various auxiliary agents and fillers to form a coating. The aqueous acrylic emulsion has better construction safety, lower odor, certain adhesive force to various base materials, relatively moderate cost, and can obtain different elasticity and hardness through formula adjustment, thereby having higher use foundation in the applications of granary sealing, dampproof, mildew proof and the like. However, the granary environment has the characteristics of large temperature and humidity fluctuation, condensation and salt/alkaline migration, frequent substrate microcrack and deformation and the like, and the traditional aqueous acrylic coating often has a plurality of limitations in terms of gas barrier capability, as the common acrylic emulsion can still have micropore channels after film formation, and when the film thickness of the coating is insufficient or microcracks and pinholes appear, the gas permeability is easy to rise, and the higher airtight level is difficult to keep for a long time. Secondly, the durability and weather resistance of the coating are also limited, and under the action of external factors such as damp heat, ultraviolet rays, alkaline substrate exudates, salt fog or cleaning agents, the problems such as chalking, whitening, light loss, embrittlement or adhesive force reduction and the like of the coating can occur, so that the airtight stability of the coating is affected. In addition, the elasticity and the hardness of the coating are difficult to be combined, namely, the coating is likely to crack due to stress concentration caused by granary structural change and temperature fluctuation, and if the coating is too soft, the surface wear resistance, scratch resistance and anti-adhesion performance are insufficient, so that new defect points are formed. Accordingly, there remains a need in the art to further explore new airtight coatings for barns and methods of preparing the same to address the above challenges and meet the needs. Disclosure of Invention Aiming at the defects in the prior art, the application aims to provide the airtight coating for the granary and the preparation method thereof. In order to achieve the above purpose, the application adopts the following technical scheme: According to the first aspect, the embodiment of the application provides an airtight coating for a granary, which comprises, by mass, 40-50 parts of acrylic emulsion, 0.2-0.45 part of layered blocking material, 4-7 parts of cross-linking agent, 3-12 parts of auxiliary agent and the balance of deionized water, and the balance of the coating is 100 parts, wherein the acrylic emulsion comprises the acrylic emulsion with a core-shell structure and comprises a core layer, an inner shell layer and an outer shell layer, the core layer comprises butyl acrylate, isooctyl acrylate and acrylic acid, the inner shell layer comprises methyl methacrylate and acrylic acid, the outer shell layer comprises styrene, methyl methacrylate and methacrylic acid, and the mass ratio of the core layer, the inner shell layer and the outer shell layer is (2.5-6.5) to (1-3.5) to 1. In an alternative embodiment, the mass ratio of butyl acrylate, isooctyl acrylate, and acrylic acid in the core layer is 1 (0.1-0.3): 0.001-0.015), and/or the mass ratio of methyl methacrylate to acrylic acid in the inner shell layer is 1 (0.06-0.25), and/or the mass ratio of styrene, methyl methacrylate, and methacrylic acid in the outer shell layer is 1 (0.9-1): 0.1-0.2. In an alternative embodiment, the layered barrier material comprises graphene oxide, and/or the crosslinking agent comprises a carbodiimide crosslinking agent and an aqueous polyurethane crosslinking agent