A method for preparing a water-based ink defoamer composition

Abstract

This invention relates to a method for preparing an ink defoamer composition, which is prepared from end-hydrogen-containing polysiloxane, allyl alcohol polyether, catalyst, hydrophobic particles, and alkynyl alcohol-modified polysiloxane. The end-hydrogen-containing polysiloxane is first thoroughly ground and mixed with silica, and then, under the action of a catalyst, a spatially structured hydrogen-containing polysiloxane is formed. This is then reacted with polyether. The resulting product exhibits significantly improved foam control performance compared to a simple mixture of polyether-modified polysiloxane and hydrophobic particles. This product, when further compounded with alkynyl alcohol-modified polysiloxane having a neutral symmetrical structure, demonstrates excellent foam control performance and is less prone to side effects such as pinholes and edge shrinkage.

Description

Technical Field

[0001] This invention relates to a method for preparing a water-based ink defoamer composition, belonging to the field of fine chemical technology. Background Technology

[0002] In daily life and industrial production, various factors can lead to the generation of excessive foam, directly impacting production efficiency and product quality, and in severe cases, halting production. In recent years, the country has vigorously promoted environmental protection measures, replacing solvent-based products with water-based ones. During the manufacturing process of water-based products, it is inevitable to add a large amount of additives to reduce the surface tension of the water system. Water-based inks are homogeneous pastes composed of binders, pigments, and additives, with most of the additives being surfactants that function as dispersants and wetting agents. These surfactants have low surface tension, resulting in numerous bubbles during both production and customer use, affecting production efficiency, the decorative properties of the coating, and, more importantly, severely reducing the protective function and lifespan of the coating. Therefore, foam control during the use of water-based inks is a crucial issue.

[0003] From a compositional perspective, defoamers are mainly classified into mineral oil-based, polyether-based, silicone-based, and modified silicone-based defoamers. In water-based ink systems, mineral oil-based and modified silicone-based defoamers are the most favored. Mineral oil-based defoamers were initially widely used due to their good compatibility with inks and the absence of pinholes and fisheyes. However, given the diverse and complex range of surfactants available, the drawbacks of mineral oil-based defoamers—poor defoaming performance and high dosage requirements—have become increasingly apparent. Most importantly, mineral oil-based defoamers can affect the gloss of inks. Therefore, most defoamers currently used in water-based inks are derived from research on modified silicone or modified polyethers. US2017158813 describes the application of epoxychlorobutane-modified polyether in water-based inks; US201100392 describes defoamers in water-based coatings and inks prepared from silica, mineral oil, and emulsifiers; Gosmeet's series of patent applications, US6391831, US6001887, US5613988, and US6187891, all revolve around polyether-modified polysiloxanes. The development of defoamers specifically for water-based inks in China is relatively lagging. Much of the technical documentation still focuses on how to emulsify silicone paste to prepare emulsions for ink production. For example, CN113069796A describes a silicone paste prepared using isomeric alcohol ether-terminated polyether-modified silicone oil and silica, which is then used for defoaming in water-based ink systems. CN109651617A describes an emulsion prepared using hydroxyl-containing polyether-modified organosilicon, exhibiting excellent defoaming performance in water-based inks. CN108299938A describes a silicone paste prepared by reacting polyether-modified silicone oil with silazane-modified nano-silica, which is then mixed with sorbitol, Tween, sodium carboxymethyl cellulose, and emulsified to prepare an ink defoamer with short defoaming time, long foam suppression time, and no oil floating phenomenon.

[0004] The problem encountered in implementing the aforementioned patent is that the defoaming ability of polyether-modified polysiloxane is insufficient, requiring the addition of silicone paste to improve defoaming and foam suppression performance, thereby affecting the compatibility between the defoamer and the ink. Therefore, balancing foam control performance and compatibility has always been a key focus of research and development.

[0005] Through extensive experimental research, the inventors of this patent developed a method to first thoroughly grind and mix end-side hydrogen-containing polysiloxane with silica, then form a spatially structured hydrogen-containing polysiloxane under the action of a catalyst, and then react it with polyether. The resulting product exhibits significantly improved foam control performance compared to the product obtained by simply mixing polyether-modified polysiloxane with hydrophobic particles. This product, when further compounded with alkynol-modified polysiloxane having a neutral symmetric structure, demonstrates good foam control performance and is less prone to side effects such as pinholes and edge shrinkage. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing an aqueous ink defoamer composition, which can effectively balance foam control performance and surface control performance.

[0007] The components of the ink defoamer composition of the present invention include end-hydrogen-containing polysiloxane, allyl alcohol polyether, catalyst, hydrophobic particles, and alkynyl alcohol-modified polysiloxane.

[0008] A. End-side hydrogen-containing polysiloxane

[0009] The end-side hydrogen-containing polysiloxane has the following structure:

[0010]

[0011] In formula (Ⅰ), subscripts a and b are subscripts of two chain segments. The end-chain hydrogen-containing polysiloxane has a dynamic viscosity of 5–50 mPa·s at 25°C, a hydrogen content of 0.05–1.2%, and at least one side-chain silane-hydrogen bond is present.

[0012] The amount of the end-side hydrogen-containing polysiloxane used is 10-60% of the total mass of the ink defoamer composition.

[0013] B. Allyl alcohol polyether

[0014] The allyl alcohol polyether has the following structural formula:

[0015] CH2=CHCH2O(EO) c (PO) d R 1

[0016] Formula (II)

[0017] In formula (II), the subscript c takes values ​​from 5 to 20, and the subscript d takes values ​​from 0 to 10. 1 The terminator is a capping group selected from hydrogen atom, methyl, ethyl, propyl, and butyl.

[0018] The amount of allyl alcohol polyether used is 20-60% of the total mass of the ink defoamer composition.

[0019] C. Catalyst

[0020] The catalyst described is a hydrosilylation catalyst, selected from metal complexes such as platinum and rhodium. These complexes are selected from one or more of the following: platinum-alcohol complexes, platinum-olefin complexes, platinum-ether complexes, platinum-ketone complexes, isopropanol chloroplatinate solution, rhodium-alcohol complexes, and rhodium-ketone salt complexes.

[0021] The amount of catalyst used is 5 to 20 ppm of the total mass of the ink defoamer composition.

[0022] D. Hydrophobic particles

[0023] The hydrophobic particles are key microparticles in the defoamer composition. These hydrophobic particles refer to metal oxides, including one or more of silicon dioxide, aluminum oxide, zinc oxide, or magnesium oxide. Preferably, this invention uses hydrophobic silicon dioxide with a specific surface area of ​​50–500 m². 2 / g.

[0024] Generally, hydrophobic silica is obtained by heating and stirring hydrophilic silica and a hydrophobic agent in a reaction vessel. The material used in this invention to make the silica surface hydrophobic is selected from low-viscosity trimethylsiloxy-terminated polydimethylsiloxane, low-viscosity hydroxyl-terminated polydimethylsiloxane, hexamethyldisilazane, hexamethyldisilazane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, tetrachlorosilane, stearic acid, stearyl alcohol, octamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, and hexamethylcyclotrisiloxane.

[0025] The hydrophobic particles mentioned above have a specific surface area of ​​120–400 m². 2 / g of fumed hydrophobic silica and a specific surface area of ​​80-150m² 2 A mixture of precipitated hydrophobic silica in a mass ratio of 4:6 to 8:2.

[0026] The amount of the hydrophobic particles used is 3-20% of the total mass of the ink defoamer composition.

[0027] E. Alkyne-modified polysiloxane

[0028] The alkynyl alcohol-modified polysiloxane described herein has the following structural formula with centrosymmetric characteristics:

[0029]

[0030] In equation (Ⅲ), the subscripts e, f and g represent the degree of aggregation of the corresponding chain segments. The value of e is 2 to 10; the value of f is 0 or an integer from 1 to 4; and the value of g is an integer from 1 to 6.

[0031] The amount of the alkynyl alcohol modified polysiloxane is 10-60% of the total mass of the ink defoamer composition.

[0032] The total mass percentage of the above-mentioned ink defoamer composition is 100%.

[0033] The preparation method of the ink defoamer composition is as follows:

[0034] First, add end-side hydrogen-containing polysiloxane A and silica D to a container, heat to 50-120°C, and maintain a speed of 1000-12,000 rpm for strong shear mixing to ensure that silica D is fully dispersed.

[0035] In the second step, catalyst C is added to the mixture obtained in the first step, and the mixture is kept at a temperature of 0.5 to 5 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, and the viscosity becomes 2 to 8 times the original. Then, allyl alcohol polyether B is added to it, and the mixture is kept at a temperature of 0.5 to 5 hours to allow the end-side hydrogen-containing polysiloxane and polyether to undergo an addition reaction to form a transparent product of polyether on the surface of the spatially branched polysiloxane.

[0036] The third step involves adding alkynyl alcohol-modified polysiloxane to the product obtained in the second step, stirring until homogeneous, and then cooling to room temperature to obtain the ink defoamer composition.

[0037] The ink defoamer composition of the present invention can be used directly or formulated into an emulsion. The raw materials involved in formulating the emulsion are as follows:

[0038]

[0039] The emulsifier refers to a nonionic surfactant selected from one or more of the following: nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, fatty acid polyoxyethylene ether, straight-chain fatty alcohol polyoxyethylene ether, branched-chain fatty alcohol polyoxyethylene ether, sorbitan monofatty acid ester, sorbitan trifatty acid ester, sorbitan monofatty acid ester polyoxyethylene ether, and castor oil polyoxyethylene ether.

[0040] The thickener is selected from one or more of polyvinyl alcohol, carbomer, xanthan gum, cellulose ethers, polyacrylates and polyacrylamide.

[0041] The water mentioned is the continuous phase constituting the oil-in-water emulsion, and it is clean water, process water, or ice in solid form used in industrial production processes.

[0042] Depending on the required shelf life of the emulsion, a certain amount of preservative and bactericide needs to be added. The preservative is selected from one or more of the following: 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benzisothiazolinone, octylisothiazolinone, 2,2-dibromo-3-hypopropoxylamide, 2-bromo-2-nitro-1,3-propanediol, potassium sorbate, p-hydroxybenzoate, iodopropynyl butylcarbamate, sodium lactate, and sodium benzoate.

[0043] The total mass percentage of all components used to prepare the emulsion is 100%.

[0044] The preparation method of the emulsion-type ink defoamer is as follows:

[0045] At room temperature, add the ink defoamer composition and emulsifier to a container and mix for 10 to 30 minutes at a speed of 300 to 2000 rpm. Then, add water within 20 to 50 minutes and process it through a homogenizer to control the emulsion particle size to 2 to 10 μm. Finally, add thickener and preservative to the emulsion to obtain the emulsion-type ink defoamer. Specific implementation methods

[0046] Example 1:

[0047] Preparation of ink defoamer composition:

[0048] First, add 17 parts of end-side hydrogen-containing polysiloxane (viscosity 6 mPa·s, hydrogen content 1.2%), 1.2 parts of fumed hydrophobic silica R972 with a specific surface area of ​​130 m2 / g, and 1.8 parts of precipitated hydrophobic silica D10 with a specific surface area of ​​80 m2 / g to a container, heat to 50°C, and maintain a speed of 1000 rpm for strong shear mixing to ensure that the silica is fully dispersed;

[0049] The second step involves adding 10 ppm of platinum-alcohol complex to the mixture obtained in the first step and maintaining the temperature for 0.5 h to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity increase of 7.5 times. Then, 20 parts of allyl alcohol polyether (c=5, d=0, R...) are added to the mixture. 1 = Hydrogen atom), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product of polyether on the surface of spatially branched polysiloxane;

[0050] The third step involves adding 60 parts of alkynyl alcohol-modified polysiloxane (e=2, f=0, g=1) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D1.

[0051] Example 2:

[0052] Preparation of ink defoamer composition:

[0053] The first step involves adding 42 parts of end-side hydrogen-containing polysiloxane (viscosity 48 mPa·s, hydrogen content 0.06%) and 14.4 parts of a specific surface area of ​​380 m² to a container. 2 / g of fumed hydrophobic silica 630 and 3.6 parts with a specific surface area of ​​150m² 2 / g of precipitated hydrophobic silica 383DS was heated to 115℃ and subjected to intense shear mixing at a speed of 11500rpm to ensure thorough dispersion of silica.

[0054] The second step involves adding 18 ppm of platinum-ketone complex to the mixture obtained in the first step and incubating it at this temperature for 4.8 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that doubles. Then, 30 parts of allyl alcohol polyether (c=18, d=2, R...) are added to the mixture. 1 =Methyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product of polyether on the surface of spatially branched polysiloxane;

[0055] The third step involves adding 10 parts of alkynyl alcohol-modified polysiloxane (e=9, f=4, g=6) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D2.

[0056] Example 3:

[0057] Preparation of ink defoamer composition:

[0058] The first step involves adding 58 parts of end-side hydrogen-containing polysiloxane (viscosity 10 mPa·s, hydrogen content 0.2%) and 3 parts of a specific surface area of ​​220 m² to a container. 2 / g of fumed hydrophobic silica R974 and 2 parts with a specific surface area of ​​100m² 2 / g of precipitated hydrophobic silica was heated to 95℃ and subjected to vigorous shear mixing at a speed of 5000rpm to ensure thorough dispersion of silica.

[0059] The second step involves adding a 5 ppm solution of chloroplatinic acid in ethanol (calculated as platinum) to the mixture obtained in the first step, and incubating for 2 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity four times its original value. Then, 25 parts of allyl alcohol polyether (c=16, d=10, R...) are added. 1 =Butyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product on the surface of the polyether that is spatially branched on the polysiloxane;

[0060] The third step involves adding 12 parts of alkynyl alcohol-modified polysiloxane (e=6, f=1, g=3) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D3.

[0061] Example 4:

[0062] Preparation of ink defoamer composition:

[0063] The first step involves adding 12 parts of end-hydrogen-containing polysiloxane (viscosity 23 mPa·s, hydrogen content 0.87%) and 7 parts of a specific surface area of ​​240 m² to a container. 2 / g of fumed hydrophobic silica and 3 parts of a specific surface area of ​​90m² 2 / g of precipitated hydrophobic silica was heated to 75℃ and subjected to intense shear mixing at a speed of 8000rpm to ensure thorough dispersion of silica.

[0064] The second step involves adding 12 ppm of rhodium-alcohol complex to the mixture obtained in the first step and incubating it at this temperature for 3 hours. This allows the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that is six times higher than before. Then, 60 parts of allyl alcohol polyether (c=10, d=3, R...) are added to the mixture. 1 =propyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product on the surface of the polyether branched in space.

[0065] The third step involves adding 18 parts of alkynyl alcohol-modified polysiloxane (e=8, f=2, g=6) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D4.

[0066] Example 5:

[0067] Preparation of ink defoamer composition:

[0068] The first step involves adding 60 parts of end-side hydrogen-containing polysiloxane (viscosity 43 mPa·s, hydrogen content 0.75%) and 1.8 parts of a specific surface area of ​​160 m² to a container. 2 / g of fumed hydrophobic silica and 1.2 parts with a surface area of ​​120m² 2 / g of precipitated hydrophobic silica was heated to 105℃ and subjected to intense shear mixing at a speed of 3000rpm to ensure thorough dispersion of silica.

[0069] The second step involves adding 8 ppm of a rhodium-ketone complex to the mixture obtained in the first step and maintaining the temperature for 2.5 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that is 8 times higher than before. Then, 22 parts of allyl alcohol polyether (c=18, d=0, R...) are added to the mixture. 1 =Ethyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product of polyether on the surface of spatially branched polysiloxane;

[0070] The third step involves adding 15 parts of alkynyl alcohol-modified polysiloxane (e=10, f=0, g=4) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D5.

[0071] Comparative Example 1:

[0072] Preparation of ink defoamer composition:

[0073] The first step involved adding 60 parts of end-hydrogen-containing polysiloxane (viscosity 43 mPa·s, hydrogen content 0.75%) and 8 ppm of rhodium-ketone complex to a container and incubating for 2.5 hours to allow the end-hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity eight times higher than before. Then, 22 parts of allyl alcohol polyether (c=18, d=0, R...) were added. 1 =Ethyl), continue to keep warm, allowing the end-containing hydrogen-containing polysiloxane and polyether to undergo an addition reaction, forming a transparent product with the polyether branched on the surface of the polysiloxane; then add 1.8 parts of a specific surface area of ​​160m² to the above transparent product. 2 / g of fumed hydrophobic silica and 1.2 parts with a surface area of ​​120m² 2 / g of precipitated hydrophobic silica was subjected to intense shear mixing at a speed of 3000rpm to ensure thorough dispersion of the silica.

[0074] In the second step, 15 parts of alkynyl alcohol modified polysiloxane (e=10, f=0, g=4) are added to the product obtained in the second step, stirred evenly, and cooled to room temperature to obtain ink defoamer composition D5-1.

[0075] Comparative Example 2:

[0076] Preparation of ink defoamer composition:

[0077] The first step involves adding 60 parts of end-side hydrogen-containing polysiloxane (viscosity 43 mPa·s, hydrogen content 0.75%) and 1.8 parts of a specific surface area of ​​160 m² to a container. 2 / g of fumed hydrophobic silica and 1.2 parts with a surface area of ​​120m² 2 / g of precipitated hydrophobic silica was heated to 105℃ and subjected to intense shear mixing at a speed of 3000rpm to ensure thorough dispersion of silica.

[0078] The second step involves adding 8 ppm of a rhodium-ketone complex and 22 parts of allyl alcohol polyether (c = 18, d = 0, R...) to the mixture obtained in the first step. 1 =Ethyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product of polyether on the surface of spatially branched polysiloxane;

[0079] The third step involves adding 15 parts of alkynyl alcohol-modified polysiloxane (e=10, f=0, g=4) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D5-2.

[0080] Comparative Example 3:

[0081] Preparation of ink defoamer composition:

[0082] The first step is to add 60 parts of end-side hydrogen-containing polysiloxane (viscosity 43 mPa·s, hydrogen content 0.75%) and 3 parts of a specific surface area of ​​160 m² to a container. 2 / g of fumed hydrophobic silica was heated to 105℃ and subjected to intense shear mixing at a speed of 3000rpm to ensure thorough dispersion of silica.

[0083] The second step involves adding 8 ppm of a rhodium-ketone complex to the mixture obtained in the first step and maintaining the temperature for 2.5 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that is 8 times higher than before. Then, 22 parts of allyl alcohol polyether (c=18, d=0, R...) are added to the mixture. 1 =Ethyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product of polyether on the surface of spatially branched polysiloxane;

[0084] The third step involves adding 15 parts of alkynyl alcohol-modified polysiloxane (e=10, f=0, g=4) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D5-3.

[0085] Comparative Example 4:

[0086] Preparation of ink defoamer composition:

[0087] The first step involves adding 70 parts of end-side hydrogen-containing polysiloxane (viscosity 43 mPa·s, hydrogen content 0.75%) and 1.8 parts of a specific surface area of ​​160 m² to a container. 2 / g of fumed hydrophobic silica and 1.2 parts with a surface area of ​​120m² 2 / g of precipitated hydrophobic silica was heated to 105℃ and subjected to intense shear mixing at a speed of 3000rpm to ensure thorough dispersion of silica.

[0088] The second step involves adding 8 ppm of a rhodium-ketone complex to the mixture obtained in the first step and incubating it at this temperature for 2.5 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that is eight times greater than before. Then, 27 parts of allyl alcohol polyether (c=18, d=0, R...) are added to the mixture. 1 =Ethyl), continue to keep warm, allowing the hydrogen-containing polysiloxane and polyether on the end side to undergo an addition reaction, forming polyether on the surface of the spatially branched polysiloxane, ink defoamer D5-4.

[0089] Comparative Example 5:

[0090] Preparation of ink defoamer composition:

[0091] The first step involves adding 60 parts of end-side hydrogen-containing polysiloxane (viscosity 43 mPa·s, hydrogen content 0.75%) and 1.8 parts of a specific surface area of ​​160 m² to a container. 2 / g of fumed hydrophobic silica and 1.2 parts with a surface area of ​​120m² 2 / g of precipitated hydrophobic silica was heated to 105℃ and subjected to intense shear mixing at a speed of 3000rpm to ensure thorough dispersion of silica.

[0092] The second step involves adding 8 ppm of a rhodium-ketone complex to the mixture obtained in the first step and maintaining the temperature for 2.5 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that is 8 times higher than before. Then, 22 parts of allyl alcohol polyether (c=18, d=0, R...) are added to the mixture. 1 =Ethyl), continue to keep warm, so that the hydrogen-containing polysiloxane and polyether on the end side can undergo an addition reaction to form a transparent product of polyether on the surface of spatially branched polysiloxane;

[0093] The third step involves adding 15 parts of alkynyl alcohol-modified hydrogen-containing polysiloxane (in the alkynyl alcohol polyether structure, f = 0, g = 4; the hydrogen content of the hydrogen-containing polysiloxane is 0.2%, and the viscosity is 10 mPa·s) to the product obtained in the second step, stirring until homogeneous, and cooling to room temperature to obtain ink defoamer composition D5.

[0094] Example 6:

[0095] Raw materials required for emulsion-type ink defoamer:

[0096]

[0097]

[0098] At room temperature, add the ink defoamer composition and emulsifier to a container and mix for 20 minutes at a speed of 1000 rpm. Then, add water within 30 minutes and process the mixture through a colloid mill to control the emulsion particle size to 2-10 μm. Finally, add thickener and preservative to the emulsion to obtain emulsion-type ink defoamer E1.

[0099] Example 7:

[0100] Raw materials required for emulsion-type ink defoamer:

[0101]

[0102] At room temperature, add the ink defoamer composition and emulsifier to a container and mix for 10 minutes at a speed of 2000 rpm. Then, add water within 50 minutes and process it through a homogenizer to control the emulsion particle size to 2-10 μm. Finally, add thickener and preservative to the emulsion to obtain emulsion-type ink defoamer E2.

[0103] Example 8:

[0104] Raw materials required for emulsion-type ink defoamer:

[0105]

[0106] At room temperature, add the ink defoamer composition and emulsifier to a container and mix for 30 minutes at a speed of 300 rpm. Then, add water within 20 minutes and process the mixture with a ball mill to control the emulsion particle size to 2-10 μm. Finally, add thickener and preservative to the emulsion to obtain emulsion-type ink defoamer E3.

[0107] The properties of the silyl ether composition prepared by the method of the present invention are mainly evaluated from the following aspects:

[0108] 1. Compatibility test:

[0109] Weigh 250g of commercially available water-based ink (composed of acrylic resin and red pigment) and 0.2g of the test sample (with equal solid content) into a container. Disperse the ink at 1500rpm for 10min, then add 50g of deionized water and let it stand for 5min. Take a small amount of the dispersion and drop it onto black and white paper. Scrape the paper evenly with a 40μm wire rod and observe the state of the dispersion on the black and white paper (pinhole condition). The pinhole condition is expressed as 1mm of pinhole per square centimeter of dry film. The results are shown in Table 1.

[0110] 2. Foam control performance:

[0111] Add 200g of water to the water-based ink mixture used for the compatibility test and mix well. Take 100g of the above diluted solution and add it to a graduated cylinder with a volume of 250ml. Blow air into the mixture at a flow rate of 1.5L / min and record the time it takes for the foam to reach the 250mL mark. The longer the time, the better the foam suppression performance. The results are shown in Table 1.

[0112] Table 1. Test results of wettability and foam control performance.

[0113] sample Compatibility / individual Foam control time D1 1 10′35″ D2 1 12′18″ D3 1 9′45″ D4 0 11′29″ D5 0 10′13″ D5-1 6 9′58″ D5-2 0 2′33″ D5-3 5 5′28″ D5-4 10 14′35″ D5-5 15 13′47″ E1 0 10′25″ E2 0 11′47″ E3 0 13′27″

[0114] The data above shows that:

[0115] The patented ink defoamer composition, whether in its original form or as an emulsion, exhibits excellent compatibility and foam control performance. In comparison, D5-1 suffers from incomplete dispersion of silica due to the lack of prior mixing and dispersion with the end-hydrogen-containing polysiloxane, thus affecting compatibility. D5-2, while exhibiting good compatibility, lacks the viscosity-increasing method of the end-hydrogen-containing polysiloxane to encapsulate the silica; therefore, while also demonstrating good compatibility, its foam control performance is weaker. D5-2 illustrates the importance of mixing different types of silica; D5-4 demonstrates the significant contribution of alkynyl alcohol-modified polysiloxanes with centrosymmetric structural characteristics to compatibility.

[0116] The above embodiments demonstrate that by using spatial branching to embed silica into the structure of polysiloxane, the effectiveness of silica can be fully utilized; the alkynyl alcohol-modified polysiloxane with the patented structure can effectively help solve the compatibility problem.

Claims

1. An ink defoamer composition, characterized in that, It consists of end-hydrogen-containing polysiloxane, allyl alcohol polyether, catalyst, hydrophobic particles, and alkynyl alcohol-modified polysiloxane. A. End-side hydrogen-containing polysiloxane, wherein the end-side hydrogen-containing polysiloxane has the following structure: Equation (I) In formula (I), subscripts a and b are subscripts of two chain segments, and the amount of end-side hydrogen-containing polysiloxane is 10-60% of the total mass of the ink defoamer composition; B. Allyl alcohol polyether, wherein the allyl alcohol polyether has the following structural formula: CH2=CHCH2O(EO) c (PO) d R 1 Formula (II) In formula (II), the subscript c takes values ​​from 5 to 20, and the subscript d takes values ​​from 0 to 1 to 10; R 1 The terminating group is selected from hydrogen atom, methyl, ethyl, propyl, and butyl; the dosage is 20-60% of the total mass of the ink defoamer composition; C. Catalyst, wherein the catalyst is selected from one or more of platinum-alcohol complexes, platinum-olefin complexes, platinum-ether complexes, platinum-ketone complexes, isopropanol chloroplatinate solution, rhodium-alcohol complexes, and rhodium-ketone salt complexes; the amount used is 5 to 20 ppm of the total mass of the ink defoamer composition; D. Hydrophobic particles, wherein the hydrophobic particles are hydrophobic silica, and the amount used is 3-20% of the total mass of the ink defoamer composition; E. Alkynol-modified polysiloxane, wherein the alkynol-modified polysiloxane has the following structural formula with centrosymmetric characteristics: Formula (III) In formula (Ⅲ), the subscripts e, f, and g represent the degree of polymerization of the corresponding repeating units. The value of e is 2 to 10; the value of f is 0 or an integer from 1 to 4; the value of g is an integer from 1 to 6; and the dosage is 10% to 60% of the total mass of the ink defoamer composition. The total mass percentage of the raw materials used to prepare the ink defoamer composition is 100%. The preparation method of the ink defoamer composition is as follows: First, add end-side hydrogen-containing polysiloxane A and silica D to a container, heat to 50~120℃, and maintain a speed of 1000~12,000 rpm for strong shear mixing to ensure that silica D is fully dispersed. The second step involves adding catalyst C to the mixture obtained in the first step and keeping it at a temperature of 0.5 to 5 hours to allow the end-side hydrogen-containing polysiloxane to undergo a spatial branching reaction, resulting in a viscosity that is 2 to 8 times higher than the original. Then, allyl alcohol polyether B is added to the mixture, and the temperature is maintained to allow the end-side hydrogen-containing polysiloxane and polyether to undergo an addition reaction, forming a transparent product of polyether on the surface of the spatially branched polysiloxane. The third step involves adding alkynyl alcohol-modified polysiloxane to the product obtained in the second step, stirring until homogeneous, and then cooling to room temperature to obtain the ink defoamer composition.

2. The ink defoamer composition according to claim 1, characterized in that, The end-side hydrogen-containing polysiloxane has a dynamic viscosity of 5~50 mPa·s at 25°C, a hydrogen content of 0.05~1.2%, and at least one side-chain silane-hydrogen bond is present.

3. The ink defoamer composition according to claim 1, characterized in that, The hydrophobic silica surface material is selected from low-viscosity trimethylsiloxy-terminated polydimethylsiloxane, low-viscosity hydroxyl-terminated polydimethylsiloxane, hexamethyldisilazane, hexamethyldisilazane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, tetrachlorosilane, stearic acid, stearyl alcohol, octamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, and hexamethylcyclotrisiloxane.

4. The ink defoamer composition according to claim 1, characterized in that, The hydrophobic silica mentioned has a specific surface area of ​​120~400 m². 2 / g of fumed hydrophobic silica and a specific surface area of ​​80~150m² 2 A mixture of precipitated hydrophobic silica in a mass ratio of 4:6 to 8:

2.

5. The ink defoamer composition according to claim 1, characterized in that, It is formulated with emulsifiers, thickeners, water, and preservatives as an emulsion-type ink defoamer, with the following mass percentages: Ink defoamer composition 5~50%; Emulsifier 0.5-5%; Thickener 0.5-3%; Water content: 45-93%; Preservative 0.1~0.5%.

6. The emulsion-type ink defoamer according to claim 5, characterized in that, The emulsifier is selected from one or more of the following: nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, fatty acid polyoxyethylene ether, straight-chain fatty alcohol polyoxyethylene ether, branched-chain fatty alcohol polyoxyethylene ether, sorbitan mono-fatty acid ester, sorbitan tri-fatty acid ester, sorbitan mono-fatty acid ester polyoxyethylene ether, sorbitan tri-fatty acid ester polyoxyethylene ether, and castor oil polyoxyethylene ether.

7. The emulsion-type ink defoamer according to claim 5, characterized in that, The thickener is selected from one or more of polyvinyl alcohol, carbomer, xanthan gum, cellulose ethers, polyacrylates and polyacrylamide.

8. The emulsion-type ink defoamer according to claim 5, characterized in that, The water mentioned is clean water, process water, or ice in solid form used in industrial production.

9. The emulsion-type ink defoamer according to claim 5, characterized in that, The preservative is selected from 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benzisothiazolinone, octylisothiazolinone, 2,2-dibromo-3-hypopropamide, 2-bromo-2-nitro-1,3-propanediol, potassium sorbate, and p-hydroxybenzoate. milk Sodium acid One or more of sodium benzoate.

10. The emulsion-type ink defoamer according to claim 5, characterized in that, The preparation method of the emulsion-type ink defoamer is as follows: At room temperature, add the ink defoamer composition and emulsifier to a container and mix at a speed of 300~2000 rpm for 10~30 min; then add water within 20~50 min and process it through a homogenizer to control the emulsion particle size to 2~10 μm; finally, add thickener and preservative to the emulsion to obtain the emulsion-type ink defoamer.

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