A strong penetration and retort resistant two-component epoxy dip coating for water-based textile paper tubes and a method for its preparation

Abstract

The application discloses a kind of strong penetration cooking-resistant type water-based textile paper tube two-component epoxy dip coating and preparation method thereof, belong to water-based paint technical field.The coating is composed of A component and B component, A component uses the composite wetting penetrant that self-emulsifying submicron water-based epoxy dispersion and sulfobutane acid dioctyl sodium salt, acetylene glycol surfactant are composed of;B component selects fast-drying water-soluble modified polyamine curing agent, adds reactive curing accelerator.By the synergy of small particle size epoxy dispersion and composite wetting penetrant, the technical problem that traditional water-based paint is poor in paper tube fiber permeability, weak adhesion is solved;At the same time, through the synergistic effect of fast-drying curing agent and accelerator, the drying time is shortened.The coating has the characteristics of low VOC content, environmental protection safety, strong penetration to paper tube substrate, fast drying speed, excellent adhesion, and the dense paint film formed after curing has the performance of saturated water vapor cooking resistance.

Description

A two-component epoxy impregnation coating for textile paper tubes with strong penetration and resistance to boiling, and its preparation method. Technical Field

[0001] This invention belongs to the field of waterborne coating technology, specifically relating to a dip coating for paper tubes in the textile industry, and more particularly to a two-component waterborne epoxy coating with excellent permeability, rapid drying ability and resistance to saturated steam cooking, and its preparation method. Background Technology

[0002] Paper tubes for textiles are widely used in the textile industry, primarily for winding various types of yarn, such as cotton yarn, synthetic fiber yarn, and wool yarn, to facilitate yarn storage, transportation, and subsequent processing. Textile mills have high humidity levels, and during textile production, the paper tubes frequently come into contact with and rub against textile equipment and yarn. Therefore, the coating for paper tubes must possess good water resistance and abrasion resistance. Additionally, the paper tubes may undergo some bending and deformation during winding, requiring the coating to simultaneously possess good flexibility and strong adhesion. Due to the high cost of yarn, to avoid economic losses caused by yarn spoilage due to paper tube swelling and deformation, paper tube processing companies typically use saturated steam boiling of finished paper tubes to test the water resistance of the coating film and control the tube breakage rate. This method determines whether the paper tube will deform, absorb water, and swell after winding. Wax / paraffin impregnation is a relatively traditional and basic treatment method, mainly aimed at improving the water and moisture resistance of the paper tubes. However, its abrasion resistance, hardness, and temperature resistance are poor, failing to meet the requirements of high-speed winding of high-end textiles (such as synthetic fiber filaments). Coating is one of the most common surface treatment methods for industrial paper tubes. By applying one or more layers of special coatings to the surface of the paper tube, the performance of the paper tube can be improved.

[0003] Currently, there are two main types of paper tube coatings on the market: 1. Solvent-based coatings: These are mainly solvent-based alkyd or epoxy varnishes. Although these coatings dry quickly and have good penetration into paper tubes, they contain large amounts of volatile organic compounds (VOCs) such as benzene and esters, with VOC content typically exceeding 500g / L. They have a strong odor, are flammable and explosive, posing serious health hazards to production workers and the environment. With increasingly stringent national environmental regulations, their application is facing greater and greater restrictions. 2. Traditional water-based coatings: These are mainly single-component acrylic emulsion coatings. Although these coatings are environmentally friendly, their film-forming mechanism relies on the physical accumulation of water after evaporation, resulting in low cross-linking density and extremely poor water resistance and boiling resistance, making it difficult to meet the performance requirements of textile paper tubes. While traditional two-component waterborne epoxy coatings offer improved chemical resistance, they still present several problems: First, the high surface tension of water results in poor wetting and penetration of the coating into the paper tube fibers, leading to poor adhesion. Second, the slow evaporation of water results in a long drying cycle, making it easy for paper tubes to stick together during dip coating, thus affecting production efficiency. Finally, the activation period is usually short, making on-site application inconvenient.

[0004] Therefore, developing a water-based textile paper tube coating that meets environmental protection requirements and has performance equal to or even better than solvent-based coatings, especially one with strong penetration, fast drying and excellent resistance to boiling, is a technical challenge that needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a highly penetrating, retort-resistant, water-based two-component epoxy impregnation coating for textile paper tubes and its preparation method. This invention solves the technical problems of poor penetration and weak adhesion of traditional water-based coatings to paper tube fibers by utilizing the action of small-particle-size epoxy dispersions and composite wetting and penetrating agents. Simultaneously, the drying time is shortened by combining fast-drying curing agents and accelerators. The prepared coating features low VOC content, environmental safety, strong penetration into paper tube substrates, fast drying speed, and excellent adhesion. The dense coating film formed after curing has resistance to saturated water vapor retort, effectively preventing deformation of the paper tube under usage conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A two-component epoxy impregnation coating for textile paper tubes with strong penetration and resistance to boiling is composed of component A and component B. Before use, component A and component B are mixed at a mass ratio of 5:1 to 10:1.

[0008] Component A, by mass parts, is made from the following raw materials:

[0009] Self-emulsifying submicron-sized aqueous epoxy dispersion: 100 parts;

[0010] Film-forming aid: 3-8 parts;

[0011] Composite wetting and penetrating agent: 0.5-2 parts;

[0012] Leveling agent: 0.2-1 part;

[0013] Defoamer: 0.1-0.5 parts;

[0014] Deionized water: 10-30 parts;

[0015] Thickener: 0.1-0.5 parts;

[0016] Component B, by mass parts, is made from the following raw materials:

[0017] Fast-drying water-soluble modified polyamine curing agent: 100 parts;

[0018] Reactive curing accelerator: 2-10 parts;

[0019] Quick-drying cosolvent: 10-20 parts;

[0020] Deionized water: 10-30 parts;

[0021] Further, the self-emulsifying submicron-sized aqueous epoxy dispersion is an aqueous dispersion of bisphenol A type epoxy resin with a solid content of 50-60%, an average particle size of less than 500 nanometers, and an epoxy equivalent of 450-550 g / eq. More preferably, it is Hansoh EPI-REZ™ 5003-W-55, Hansoh EPI-REZ™ 3520-WY-55, or Huntsman Araldite® PZ 3961-1.

[0022] Furthermore, the composite wetting and penetrating agent is formulated by compounding sodium dioctyl sulfosuccinate and acetylene glycol surfactant in a mass ratio of 1:1 to 1:3. The acetylene glycol surfactant is 2,4,7,9-tetramethyl-5-decyn-4,7-diol (TMDD).

[0023] Furthermore, the film-forming aid is one or a mixture of two of dipropylene glycol butyl ether or propylene glycol phenyl ether and dodecyl alcohol ester;

[0024] Furthermore, the leveling agent is BYK-348 or BYK-3455 from BYK Chemicals.

[0025] Furthermore, the defoamer is an organosilicon-based agent;

[0026] Furthermore, the thickener is preferably a nonionic associative polyurethane thickener, HEUR.

[0027] Further, the fast-drying water-soluble modified polyamine curing agent is a water-soluble modified aliphatic amine or modified alicyclic amine curing agent with a solid content of 45-55% and an active hydrogen equivalent of 80-150 g / eq. Further, Cardlite LITE 3040, Cardlite NX-8101, or Huntsman Aradur® 3986 XW 55 are preferred.

[0028] Furthermore, the reactive curing accelerator is a tertiary amine compound containing active hydrogen, preferably 2,4,6-tris(dimethylaminomethyl)phenol.

[0029] Furthermore, the fast-drying cosolvent is one or a mixture of at least two of ethanol, isopropanol, or n-butanol.

[0030] The present invention also provides a method for preparing the above-mentioned coating, comprising the following steps:

[0031] (1) Preparation of component A: Add a measured amount of self-emulsifying submicron-sized aqueous epoxy dispersion to a stirred tank. While stirring, add film-forming aid, composite wetting and penetrating agent, leveling agent and defoamer in sequence. Stir at medium speed for 15-30 minutes to disperse it evenly. Then slowly add deionized water and finally add thickener to adjust to the application viscosity. Adjust the viscosity of the coating to 40±5 seconds under the test conditions of Forecast-4 cup (25℃). After stirring evenly, filter and discharge to obtain component A.

[0032] (2) Preparation of component B: In a clean stirred tank, add the measured amount of fast-drying water-soluble modified polyamine curing agent, start stirring, and add the reactive curing accelerator, fast-drying cosolvent and deionized water in sequence. Stir for 25~35 minutes, and pay attention to controlling the system temperature not to exceed 40℃ until the system is clear and transparent. Filter the material to obtain component B.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) This invention uses an epoxy emulsion with an average particle size of less than 500 nanometers, combined with a composite wetting and penetrating agent. The sodium dioctyl sulfosuccinate in the composite wetting and penetrating agent can quickly reduce the surface tension of the coating. The acetylene glycol surfactant, as a low-foaming wetting agent, further helps the penetration, allowing the coating to easily and quickly penetrate into the interior of the paper tube fibers, improving the adhesion of the paint film and effectively preventing the paint film from peeling off. Furthermore, a cross-linking network is formed between the polyamine curing agent and the epoxy resin, and a reactive accelerator is introduced to further enhance the cross-linking, making the paint film dense. After cooking in saturated steam for 2.0 hours, the paint film does not bubble or peel off, and the paper tube is undamaged and undeformed.

[0035] (2) The present invention uses the combined action of fast-drying curing agent and reactive accelerator, combined with fast-drying cosolvent, to shorten the drying time of the paint film. The surface drying time is ≤1 hour, which solves the problems of low construction efficiency and easy sticking to pipes of water-based coatings.

[0036] (3) The present invention uses water as the dispersion medium and the co-solvent used is a low-toxicity alcohol. The amount used is small and the VOC content is extremely low. Compared with traditional solvent-based coatings, it improves the working environment and is environmentally friendly and safe. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below. The self-emulsifying submicron-sized aqueous epoxy dispersion is Hansen EPI-REZ™ 3520-WY-55; the leveling agent is BYK-348 from BYK Chemical. The fast-drying water-soluble modified polyamine curing agent is Huntsman Aradur® 3986 XW 55. The polyurethane thickener is selected from the nonionic associative polyurethane thickener HEUR, and the acetylene glycol surfactant is 2,4,7,9-tetramethyl-5-decyn-4,7-diol (TMDD). Example 1:

[0038] A two-component epoxy impregnation coating for textile paper tubes with strong penetration and resistance to boiling.

[0039] (1) Component A

[0040] Self-emulsifying submicron-sized aqueous epoxy dispersion: 100 kg;

[0041] Propylene glycol phenyl ether: 5 kg;

[0042] Composite wetting and penetrating agent: Sodium dioctyl sulfosuccinate and ethynyl diol surfactant (TMDD) in a 1:2 ratio: 1.5 kg;

[0043] Leveling agent: 0.5 kg;

[0044] Organosilicon defoamer: 0.3 kg;

[0045] Deionized water: 20kg;

[0046] Polyurethane thickener: 0.3kg

[0047] Add the self-emulsifying submicron-sized aqueous epoxy dispersion, film-forming aid, composite wetting and penetrating agent, leveling agent, and defoamer to a 1000L stirred tank. Start stirring and mix at 300 rpm for 20 minutes to ensure uniform dispersion. Then, slowly add 20 kg of deionized water and continue stirring for 10 minutes. Finally, add 0.3 kg of polyurethane thickener under low-speed stirring to adjust the viscosity to 40 seconds at Forecast cup (25°C). After thorough mixing, filter to obtain component A.

[0048] (2) Preparation of component B:

[0049] Fast-drying water-soluble modified fatty amine curing agent: 100kg

[0050] 2,4,6-Tris(dimethylaminomethyl)phenol: 6 kg

[0051] Quick-drying cosolvent isopropanol: 15kg

[0052] Deionized water: 25kg

[0053] Add the above materials to a 500L stirred tank, start stirring, and stir at 400 rpm for 30 minutes, controlling the temperature not to exceed 40℃, until the system is completely homogeneous and clear. Filter to obtain component B.

[0054] Before construction, thoroughly mix component A and component B at a mass ratio of 8:1. Example 2:

[0055] A two-component epoxy impregnation coating for textile paper tubes with strong penetration and resistance to boiling.

[0056] (1) Component A

[0057] Self-emulsifying submicron-sized aqueous epoxy dispersion: 100 kg;

[0058] Propylene glycol phenyl ether: 7 kg;

[0059] Composite wetting and penetrating agent: Sodium dioctyl sulfosuccinate and ethynyl diol surfactant (TMDD) in a 1:1 ratio: 1.0 kg;

[0060] Leveling agent: 0.8 kg;

[0061] Organosilicon defoamer: 0.4 kg;

[0062] Deionized water: 15kg;

[0063] Polyurethane thickener: 0.4 kg;

[0064] Add the self-emulsifying submicron-sized aqueous epoxy dispersion, film-forming aid, composite wetting and penetrating agent, leveling agent, and defoamer to a 1000L stirred tank. Start stirring and mix at 300 rpm for 25 minutes to ensure uniform dispersion. Then, slowly add 15 kg of deionized water and continue stirring for 10 minutes. Finally, add 0.4 kg of polyurethane thickener under low-speed stirring to adjust the viscosity to 45 seconds at Forecast cup (25°C). After thorough mixing, filter to obtain component A.

[0065] (2) Preparation of component B:

[0066] Fast-drying water-soluble modified fatty amine curing agent: 100kg

[0067] 2,4,6-Tris(dimethylaminomethyl)phenol: 9kg

[0068] fast-drying cosolvent n-butanol: 10kg

[0069] Deionized water: 15kg

[0070] Add the above materials to a 500L stirred tank, start stirring, and stir at 400 rpm for 35 minutes, controlling the temperature not to exceed 40℃, until the system is completely homogeneous and clear. Filter to obtain component B.

[0071] Before construction, mix component A and component B thoroughly at a mass ratio of 10:1.

[0072] Comparative Example 1:

[0073] The difference between Comparative Example 1 and Example 1 is that, except that the self-emulsifying submicron-sized aqueous epoxy dispersion in component A is replaced with an equal amount of conventional aqueous epoxy emulsion (Nanya Plastics: NPEW-261W55), the other components and preparation methods are the same as in Example 1.

[0074] Comparative Example 2:

[0075] The difference between Comparative Example 2 and Example 1 is that the composite wetting and penetrating agent in component A is replaced with an equal amount of sodium dioctyl sulfosuccinate, while the other components and preparation methods are the same as in Example 1.

[0076] Comparative Example 3:

[0077] Compared with Example 1, Comparative Example 3 differs in that the ethynylene glycol surfactant (TMDD) in the composite wetting and penetrating agent of component A is replaced with an equal amount of fatty alcohol polyoxyethylene ether (AEO), while the other components and preparation methods are the same as in Example 1.

[0078] Comparative Example 4:

[0079] The difference between Comparative Example 4 and Example 1 is that, except for the absence of a reactive curing accelerator in component B, the other components and preparation methods are the same as in Example 1.

[0080] The components A and B prepared in the above embodiments and comparative examples were mixed according to the mass ratio specified in the embodiments, and stirred with an electric stirrer for 3-5 minutes until the system was homogeneous. The pot life test environment for the mixed coating was 25℃ and 60%RH. The coating was applied using a dip-coating method. Standard curing conditions were used for the paint film: 25±2℃ and 65±5%RH. All paint film performance tests were conducted after 7 days of curing under standard conditions to ensure complete curing of the paint film.

[0081] Table 1:

[0082] Test ItemsTest StandardsExample 1Example 2Comparative Example 1Comparative Example 2Comparative Example 3Comparative Example 4Appearance of Paint FilmVisual inspectionThe paint film is smooth and flat without defectsThe paint film is flat with high glossThe surface of the paint film is rough with a granular feelThere are a small number of pinholes in the paint filmThere are a large number of pinholes and shrinkage holes in the paint filmThe paint film is smooth and flatSurface Drying Time (h, 25℃)GB / T 1728-1979≤ 1.0≤ 1.2≤ 1.5≤ 1.0≤ 1.0>10.0Hard Drying Time (baked at 80℃, h)GB / T 1728-1979≤ 0.5≤ 0.5≤ 0.6≤ 0.5≤ 0.5>3.0Adhesion (grade)GB / T 9286114231Hardness (Pencil Method)GB / T 6739H2HBHF<HB (softening)Gloss (60°)GB / T 9754859060826580Flexibility (mm)GB / T 1731121111Steam Resistance (100℃ saturated steam, 2.0 h)Enterprise StandardNo blistering, no peelingNo blistering, no peelingSerious blistering and peelingSlight loss of gloss, blisteringObvious blistering and loss of glossThe paint film softens and turns whiteAbrasion Resistance (mass loss, g)Taber Abrasion Test (under a load of 500 g and CS-10 abrasive wheel, 1000 revolutions)1210>50 (paint film peeling)203525 Table

[0083] The coatings of Example 1 and Example 2 can dry quickly, have an adhesion of grade 1, mechanical properties: H hardness, 1 mm flexibility, and excellent steam resistance.

[0084] In Comparative Example 1, the submicron epoxy was replaced with conventional micron-sized epoxy. The micron-sized particles were difficult to penetrate the paper tube fibers smoothly, and only a paint film with poor surface adhesion and loose structure could be formed. This paint film could not resist the erosion of water vapor, resulting in the failure of the interface due to damage. In Comparative Example 2, the acetylene glycol surfactant in the composite wetting agent was removed, resulting in a decrease in adhesion, pinholes in the paint film, and a deterioration in steam resistance. In Comparative Example 3, TMDD was replaced with a conventional fatty alcohol polyoxyethylene ether, generating a large amount of foam, serious paint film defects, further deterioration in adhesion, and obvious deterioration in steam resistance. The synergistic effect between the combination of dioctyl sulfosuccinate sodium salt and TMDD was demonstrated. The sulfosuccinate quickly wets, and TMDD further penetrates, ensuring a dense and defect-free paint film. In the absence of TMDD penetration and insufficient density. In Comparative Example 4, the accelerator DMP-30 was removed, resulting in a significant increase in drying time, unable to meet the efficiency requirements of industrial production. Within the conventional detection period, the paint film was soft, and the steam resistance was poor, showing softening and whitening because the cross-linking reaction was incomplete and a paint film with a dense network structure was not formed.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly penetrating, retort-resistant, water-based two-component epoxy impregnation coating for textile paper tubes, characterized in that, Composed of component A and component B, components A and B are mixed at a mass ratio of 5:1 to 10:1 before use; component A is made from the following raw materials by mass: self-emulsifying submicron waterborne epoxy dispersion: 100 parts; film-forming aid: 3-8 parts; composite wetting and penetrating agent: 0.5-2 parts; Leveling agent: 0.2-1 part; Defoamer: 0.1-0.5 parts; Deionized water: 10-30 parts; Thickener: 0.1-0.5 parts; Component B, by mass, is made from the following raw materials: water-soluble modified polyamine curing agent: 100 parts; curing accelerator: 2-10 parts; fast-drying co-solvent: 10-20 parts; deionized water: 10-30 parts; wherein, the composite wetting and penetrating agent is compounded from sodium dioctyl sulfosuccinate and acetylene glycol surfactant in a mass ratio of 1:1 to 1:3; wherein the self-emulsifying submicron-sized aqueous epoxy dispersion is an aqueous dispersion of bisphenol A type epoxy resin with an average particle size of less than 500 nanometers, a solid content of 50-60%, and an epoxy equivalent of 450-550 g / eq; the acetylene glycol surfactant in the composite wetting and penetrating agent is 2,4,7,9-tetramethyl-5-decyn-4,7-diol; the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

2. The highly penetrating, retort-resistant, water-based two-component epoxy impregnation coating for textile paper tubes according to claim 1, characterized in that, The film-forming aid is one or a mixture of at least two of dipropylene glycol butyl ether, propylene glycol phenyl ether, or dodecyl alcohol ester; the thickener is a nonionic associative polyurethane thickener.

3. A method for preparing a two-component epoxy impregnation coating for textile paper tubes with strong penetration and resistance to boiling, as described in any one of claims 1-2, characterized in that, Includes the following steps: (1) Preparation of component A: Add self-emulsifying submicron-sized aqueous epoxy dispersion to a stirred tank. While stirring, add film-forming aid, composite wetting and penetrating agent, leveling agent and defoamer in sequence. Stir at medium speed for 15-30 minutes. Then add deionized water. Finally, add thickener to adjust the viscosity to 35-45 seconds under the test conditions of Fore-4 cup at 25℃. After stirring evenly, filter out the material to obtain component A. (2) Preparation of component B: Add water-soluble modified polyamine curing agent to a stirred tank. Start stirring. Add curing accelerator, fast-drying cosolvent and deionized water in sequence. Stir for 25-35 minutes under the condition of controlling the temperature not to exceed 40℃ until the system is clear and transparent. Filter out the material to obtain component B.