A method for preparing an ink system defoaming composition

Abstract

The present application relates to a kind of preparation methods of ink system defoaming composition with oil, it is prepared by modified polysiloxane, silicon dioxide, catalyst, polyether-polysiloxane copolymer and alkyne alcohol polyether.The modified polysiloxane with new structure and silicon dioxide under the action of catalyst form defoaming composition, then again with the alkyne alcohol polyether with neutral symmetrical structure and polyether-polysiloxane copolymer compound, the composition obtained has good foam control performance, and the compatibility of ink system is good, and side effect such as shrinkage hole, shrinkage edge is not easy to produce.

Description

Technical Field

[0001] This invention relates to a method for preparing an ink system defoaming composition, belonging to the field of fine chemical technology. Background Technology

[0002] Water-based inks are homogeneous pastes composed of binders, pigments, and additives. Most of the additives used are surfactants, which function to disperse and wet. These surfactants have low surface tension, leading to the generation of numerous bubbles both during production and customer use. This negatively impacts production efficiency and the decorative properties of the coating, and more importantly, severely reduces the protective function and lifespan of the coating. Therefore, foam control during the production and use of water-based inks is a crucial issue.

[0003] Defoamers are substances commonly used to eliminate harmful air bubbles. From a compositional perspective, defoamers are mainly classified into mineral oil-based, polyether-based, silicone-based, and modified silicone-based defoamers. Specifically, in water-based ink systems, mineral oil-based and modified silicone-based defoamers are the most favored. Mineral oil-based defoamers were widely used in the early days because of their good compatibility with inks and the absence of pinholes and fisheyes. For example, US201100392 describes defoamers used in water-based coatings and inks prepared with silica, mineral oil, and emulsifiers. However, given the diverse and complex nature of surfactants, the drawbacks of mineral oil-based defoamers—poor defoaming performance and high dosage—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 polyether. For example, CN101088589 introduces ABA-type block silicone polyether defoamers; CN101096417, CN101541858A, US5804099A, US5613988A, and US20020132860 mainly introduce branched polyether-modified polysiloxanes, controlling foam control performance by adjusting the water solubility of silicone polyethers; US6391831B1 introduces styrene-modified polysiloxane defoamers; US201032425A introduces fluorinated polyether-modified polysiloxane defoamers; and US2017158813 introduces the application of epichlorohydrin-modified polyethers in water-based inks. The domestic market for defoamers specifically for water-based inks is relatively underdeveloped. Many technical documents still describe how silicone paste is emulsified to prepare emulsions for use in ink production. For example, CN113069796A describes a method for preparing silicone paste using end-group isomeric alcohol ether-terminated polyether-modified silicone oil and silica, and how this silicone paste is used in water-based ink systems. CN109651617A describes a method for preparing emulsions using hydroxyl-containing polyether-modified organosilicon, which exhibits excellent defoaming properties in water-based inks.

[0004] The problem encountered in implementing the aforementioned patents is that the defoaming ability of polyether-modified polysiloxanes is insufficient. People often consider adding silicone grease to improve defoaming and foam-suppressing performance, which creates a contradiction between defoaming performance and compatibility. 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 novel modified polysiloxane and silica composition to form an antifoaming composition under the action of a catalyst. This composition, when combined with alkynyl alcohol polyether and polyether-polysiloxane copolymer with a neutral symmetrical structure, exhibits 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 ink system defoaming composition, which can effectively balance foam control performance and surface control performance.

[0007] The components of the ink system defoaming composition of the present invention include modified polysiloxane, silica, catalyst, polyether-polysiloxane copolymer and alkynyl alcohol polyether.

[0008] A. Modified polysiloxane

[0009] The modified polysiloxane is obtained by hydrosilylation reaction of hydrogen-containing polysiloxane, tris(trimethylsiloxy)vinylsilane, and xylitol allyl ether under the action of chloroplatinic acid.

[0010] The structural formula of the hydrogen-containing polysiloxane is as follows:

[0011]

[0012] In formula (Ⅰ), the subscripts a and b represent the average degree of polymerization of the two repeating units. The dynamic viscosity of the hydrogen-containing polysiloxane at 25°C is 5–30 mPa·s, and the hydrogen content is 0.1–1.2%.

[0013] The raw materials used to prepare the modified polysiloxane are as follows (by weight percentage):

[0014]

[0015] The sum of the above-mentioned mass percentages is 100%.

[0016] The modified polysiloxane is prepared by adding hydrogen-containing polysiloxane and tris(trimethylsiloxy)vinylsilane to a flask, stirring and heating. When the temperature reaches 60-80°C, 1-2 ppm of chloroplatinic acid catalyst is added and the temperature is maintained for 10-30 minutes. Then, xylitol allyl ether and the remaining chloroplatinic acid catalyst are added, and the temperature is further increased to 100-140°C and maintained until the product in the flask becomes transparent. The product is then cooled to room temperature to obtain the modified polysiloxane.

[0017] The amount of the modified polysiloxane used is 10-60% of the total mass of the defoaming composition of the ink system.

[0018] B. Silicon dioxide

[0019] Silica is classified into two types according to its manufacturing method: precipitated silica and fumed silica. It is also classified into two types according to its surface properties: hydrophilic silica and hydrophobic silica. The preferred specific surface area of ​​this invention is 50–500 m². 2 / g hydrophobic silica.

[0020] 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.

[0021] The silica described in this invention has a specific surface area of ​​50-200 m². 2 / g and specific surface area 250-500m² 2 A composition of two hydrophobic silicas with different specific surface areas per g, wherein the difference in their specific surface areas is greater than 80 m². 2 / g.

[0022] The amount of silica used is 3-20% of the total mass of the defoaming composition in the ink system.

[0023] C. Catalyst

[0024] The catalyst is selected from sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium acetate, monoethanolamine, diethanolamine, and triethanolamine.

[0025] The amount of the catalyst used is 0.1% to 2% of the total mass of the defoaming composition in the ink system.

[0026] D. Polyether-polysiloxane copolymer

[0027] The polyether-polysiloxane copolymer has the following structural formula:

[0028]

[0029] In formula (II), the subscript c takes values ​​from 5 to 20, and the subscripts d and e are the average degrees of polymerization of ethylene oxide (EO) and propylene oxide (PO), respectively, with d being 1 to 15 and e being 0 or 1 to 15; R is selected from methyl, ethyl, propyl, butyl, and acetyl.

[0030] The amount of the polyether-polysiloxane copolymer used is 20-60% of the total mass of the ink system defoaming composition.

[0031] E. Acynyl alcohol polyether

[0032] The general structural formula of the alkynyl alcohol polyether is as follows:

[0033]

[0034] In formula (Ⅲ), the subscripts f and g represent the average degree of polymerization of ethylene oxide (EO) and propylene oxide (PO), and the average values ​​of f and g are 1 to 10; R 1 It is an alkyl group with 1 to 6 hydrogen atoms and carbon atoms.

[0035] The amount of the alkynyl alcohol polyether used is 10-30% of the total mass of the ink system defoaming composition.

[0036] The total mass percentage of the raw materials used in preparing the defoaming composition of the ink system is 100%.

[0037] The preparation method of the defoaming composition of the ink system is as follows:

[0038] The first step is to add modified polysiloxane A, silica B and catalyst C to a container, heat to 100-150°C, and mix vigorously at a speed of 2000-5000 rpm for 2-6 hours. Finally, the mixture is treated with a homogenizer under a pressure of 1-10 MPa to disperse silica B into particles smaller than 1000 nm.

[0039] The second step involves adding polyether-polysiloxane D and alkynyl alcohol polyether E to the mixture obtained in the first step and mixing them evenly to obtain the ink system defoaming composition.

[0040] The defoaming composition of the ink system of the present invention can be used directly or prepared into an emulsion. The mass percentages of the raw materials for preparing the emulsion are as follows:

[0041]

[0042] The total mass percentage of all raw materials used in preparing the emulsion is 100%.

[0043] The emulsifier is a nonionic surfactant selected from one or more of the following: nonanoic 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, sorbitan trifatty acid ester polyoxyethylene ether, and castor oil polyoxyethylene ether.

[0044] The thickener is selected from one or more of polyvinyl alcohol, carbomer, xanthan gum, cellulose ethers, polyacrylates and polyacrylamide.

[0045] The water mentioned is the continuous phase constituting the oil-in-water emulsion; it is clean water or ice in solid form used in industrial production processes.

[0046] 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-nitropropionamide, 2-bromo-2-nitro-1,3-propanediol, potassium sorbate, p-hydroxybenzoate, sodium lactate, and sodium benzoate.

[0047] The preparation method of the defoamer for the emulsion-type ink system is as follows:

[0048] At room temperature, add the ink defoamer composition and emulsifier to the container, set the rotation speed to 1000-3000 rpm, add the designed amount of water within 20-50 minutes, and then process it through a homogenizer to control the emulsion particle size to 1-5 μm. Finally, add thickener and preservative to the emulsion to obtain the emulsion-type ink system defoamer. Specific implementation methods

[0049] Example 1:

[0050] Preparation of modified polysiloxane A1:

[0051] Add 76 parts of hydrogen-containing polysiloxane (dynamic viscosity at 25°C is 5.5 mPa·s, hydrogen content is 0.75%) and 7 parts of tris(trimethylsiloxyvinylsilane) to a flask, then start stirring and heating. When the temperature reaches 60°C, add 2 ppm of chloroplatinic acid catalyst and keep warm for 10 min. Then add 16 parts of xylitol allyl ether and 2 ppm of chloroplatinic acid catalyst, and continue heating to 140°C and keep warm until the product in the flask becomes transparent. Cool down to room temperature to obtain modified polysiloxane A1.

[0052] Example 2:

[0053] Preparation of modified polysiloxane A2:

[0054] Add 35 parts of hydrogen-containing polysiloxane (dynamic viscosity of 27 mPa·s at 25°C, hydrogen content of 1.15%) and 9 parts of tris(trimethylsiloxyvinylsilane) to a flask, then start stirring and heating. When the temperature reaches 80°C, add 1 ppm of chloroplatinic acid catalyst and keep warm for 20 min. Then add 55 parts of xylitol allyl ether and 7 ppm of chloroplatinic acid catalyst, and continue heating to 115°C and keep warm until the product in the flask becomes transparent. Cool down to room temperature to obtain modified polysiloxane A2.

[0055] Example 3:

[0056] Preparation of modified polysiloxane A3:

[0057] Add 65 parts of hydrogen-containing polysiloxane (dynamic viscosity at 25°C is 16 mPa·s, hydrogen content is 0.13%) and 6 parts of tris(trimethylsiloxyvinylsilane) to a flask, then start stirring and heating. When the temperature reaches 68°C, add 1.6 ppm of chloroplatinic acid catalyst and keep warm for 30 min. Then add 28 parts of xylitol allyl ether and 5 ppm of chloroplatinic acid catalyst, and continue heating to 105°C and keep warm until the product in the flask becomes transparent. Cool to room temperature to obtain modified polysiloxane A3.

[0058] Example 4:

[0059] Preparation of modified polysiloxane A4:

[0060] Add 45 parts of hydrogen-containing polysiloxane (dynamic viscosity of 21 mPa·s at 25°C, hydrogen content of 0.35%) and 7 parts of tris(trimethylsiloxy)vinylsilane to a flask, then start stirring and heating. When the temperature reaches 73°C, add 1.2 ppm of chloroplatinic acid catalyst and keep warm for 23 min. Then add 47 xylitol allyl ether and 4.2 ppm of chloroplatinic acid catalyst, and continue heating to 114°C and keep warm until the product in the flask becomes transparent. Cool to room temperature to obtain modified polysiloxane A4.

[0061] Example 5:

[0062] Preparation of modified polysiloxane A5:

[0063] 68 parts of hydrogen-containing polysiloxane (dynamic viscosity at 25°C: 10.4 mPa·s, hydrogen content: 0.20%) and 8 parts of tris(trimethylsiloxyvinylsilane) were added to a flask, and stirring was started while heating. At 63°C, 1.8 ppm of chloroplatinic acid catalyst was added, and the temperature was maintained for 16 min. Then, 23 parts of xylitol allyl ether and 5.2 ppm of chloroplatinic acid catalyst were added, and the temperature was further increased to 128°C and maintained until the product in the flask became transparent. The mixture was then cooled to room temperature to obtain modified polysiloxane A5. Comparative Example 1:

[0064] Preparation of modified polysiloxane A51 (without the use of tritrimethylsiloxyvinylsilane in the reaction):

[0065] 74.8 parts of hydrogen-containing polysiloxane (dynamic viscosity at 25°C was 10.4 mPa·s, hydrogen content was 0.20%) were added to a flask, stirring was started and the temperature was raised. When the temperature reached 63°C, 1.98 ppm of chloroplatinic acid catalyst was added and the temperature was maintained for 16 min. Then, 25.3 parts of xylitol allyl ether and 5.72 ppm of chloroplatinic acid catalyst were added, and the temperature was raised to 128°C and maintained until the product in the flask became transparent. The product was then cooled to room temperature to obtain modified polysiloxane A51.

[0066] Comparative Example 2:

[0067] Preparation of modified polysiloxane A52 (using polyether instead of xylitol allyl ether in the reaction):

[0068] 74.8 parts of hydrogen-containing polysiloxane (dynamic viscosity at 25℃ is 10.4 mPa·s, hydrogen content is 0.20%) were added to a flask, stirring was started and the temperature was raised. When the temperature reached 63℃, 1.98 ppm of chloroplatinic acid catalyst was added and the temperature was maintained for 16 min. Then, 25.3 parts of allyl polyether (structural formula CH2=CHCH2(EO)4H) and 5.72 ppm of chloroplatinic acid catalyst were added, and the temperature was raised to 128℃ and maintained until the product in the flask became transparent. The product was then cooled to room temperature to obtain modified polysiloxane A52.

[0069] Example 6:

[0070] Preparation of DF-1 defoaming composition for ink system

[0071] The first step involves adding 56 parts of modified polysiloxane A2, 0.5 parts of potassium carbonate catalyst, and 2 parts of precipitated hydrophobic silica (with a specific surface area of ​​70 m²) to a container. 2 / g) and 2 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 105℃, and vigorously sheared and mixed at 3500rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 5MPa to disperse the silica into particles of 800nm.

[0072] The second step involves adding 21 parts of polyether-polysiloxane D (subscript c=10, d=9, e=0, R is n-butyl) and 18.5 parts of alkynyl alcohol polyether E (subscript f=6, g=5, R is n-butyl) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-1 of the ink system is obtained.

[0073] Example 7:

[0074] Preparation of DF-2 defoaming composition for ink system

[0075] The first step involves adding 12 parts of modified polysiloxane A4, 0.2 parts of sodium bicarbonate catalyst, and 2 parts of fumed hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 / g) and 1 part of fumed hydrophobic silica (specific surface area of ​​450m²) 2 / g), heated to 132℃, and vigorously sheared and mixed at 4800rpm for 5.5h. Finally, it was treated with a homogenizer under a pressure of 9MPa to disperse the silica into particles of 650nm.

[0076] The second step involves adding 58 parts of polyether-polysiloxane D (subscript c=5, d=14, e=8, R is acetyl) and 26.8 parts of alkynyl alcohol polyether E (subscript f=2, g=9, R is acetyl) to the mixture obtained in the first step. 1 The ink system defoaming composition DF-2 is obtained by mixing n-butyl with the product evenly.

[0077] Example 8:

[0078] Preparation of DF-3 defoaming composition for ink systems

[0079] The first step involves adding 36.2 parts of modified polysiloxane A1, 1.8 parts of sodium acetate catalyst, and 3 parts of fumed hydrophobic silica (with a specific surface area of ​​200 m²) to a container. 2 / g) and 7 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 147℃, and subjected to strong shear mixing at 2200rpm for 2.5h. Finally, it was treated with a homogenizer under a pressure of 1.2MPa to disperse the silica into particles of 963nm.

[0080] The second step involves adding 40 parts of polyether-polysiloxane D (subscript c=18, d=2, e=2, R is methyl) and 12 parts of alkynyl alcohol polyether E (subscript f=9, g=2, R is methyl) to the mixture obtained in the first step. 1 When the hexyl group is mixed evenly, the defoaming composition DF-3 of the ink system is obtained.

[0081] Example 9:

[0082] Preparation of DF-4, an antifoaming composition for ink systems

[0083] The first step involves adding 59 parts of modified polysiloxane A5, 1 part of sodium bicarbonate catalyst, and 10 parts of fumed hydrophobic silica (with a specific surface area of ​​150 m²) to a container. 2 / g) and 8 parts of fumed hydrophobic silica (specific surface area of ​​260m²) 2 / g), heated to 132℃, and vigorously sheared and mixed at 2900rpm for 4h. Finally, it was treated with a homogenizer under a pressure of 6MPa to disperse the silica into particles of 560nm.

[0084] The second step involves adding 20 parts of polyether-polysiloxane D (subscripts c=12, d=10, e=14, R is propyl) and 12 parts of alkynyl alcohol polyether E (subscript f=4, g=4, R is propyl) to the mixture obtained in the first step. 1 When methyl groups are mixed evenly, the defoaming composition DF-4 for the ink system is obtained.

[0085] Comparative Example 3:

[0086] Preparation of the ink system defoaming composition DF-41 (using modified polysiloxane A51 instead of A5).

[0087] The first step involves adding 59 parts of modified polysiloxane A51, 1 part of sodium bicarbonate catalyst, and 10 parts of fumed hydrophobic silica (with a specific surface area of ​​150 m²) to a container. 2 / g) and 8 parts of fumed hydrophobic silica (specific surface area of ​​260m²) 2 / g), heated to 132℃, and vigorously sheared and mixed at 2900rpm for 4h. Finally, it was treated with a homogenizer under a pressure of 6MPa to disperse the silica into particles of 560nm.

[0088] The second step involves adding 20 parts of polyether-polysiloxane D (subscripts c=12, d=10, e=14, R is propyl) and 12 parts of alkynyl alcohol polyether E (subscript f=4, g=4, R is propyl) to the mixture obtained in the first step. 1 When methyl groups are mixed evenly, the defoaming composition DF-41 of the ink system is obtained.

[0089] Comparative Example 4:

[0090] Preparation of defoaming composition DF-42 for ink systems (using modified polysiloxane A52 instead of A5).

[0091] The first step involves adding 59 parts of modified polysiloxane A52, 1 part of sodium bicarbonate catalyst, and 10 parts of fumed hydrophobic silica (with a specific surface area of ​​150 m²) to a container. 2 / g) and 8 parts of fumed hydrophobic silica (specific surface area of ​​260m²) 2 / g), heated to 132℃, and vigorously sheared and mixed at 2900rpm for 4h. Finally, it was treated with a homogenizer under a pressure of 6MPa to disperse the silica into particles of 560nm.

[0092] The second step involves adding 20 parts of polyether-polysiloxane D (subscripts c=12, d=10, e=14, R is propyl) and 12 parts of alkynyl alcohol polyether E (subscript f=4, g=4, R is propyl) to the mixture obtained in the first step. 1 When methyl groups are mixed evenly, the defoaming composition DF-42 for the ink system is obtained.

[0093] Example 10:

[0094] Preparation of DF-5 defoaming composition for ink systems

[0095] The first step involves adding 40 parts of modified polysiloxane A3, 0.5 parts of catalyst monoethanolamine, and 2 parts of precipitated hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 123℃, and vigorously sheared and mixed at 3800rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 3MPa to disperse the silica into particles of 780nm.

[0096] The second step involves adding 43.5 parts of polyether-polysiloxane D (subscript c=10, d=10, e=5, R is methyl) and 11 parts of alkynyl alcohol polyether E (subscript f=8, g=3, R is methyl) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-5 of the ink system is obtained.

[0097] Comparative Example 5:

[0098] Preparation of DF-51, an antifoaming composition for ink systems (removal of weakly alkaline catalyst)

[0099] The first step is to add 40.5 parts of modified polysiloxane A3 and 2 parts of precipitated hydrophobic silica (specific surface area of ​​110 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 123℃, and vigorously sheared and mixed at 3800rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 3MPa to disperse the silica into particles of 780nm.

[0100] The second step involves adding 43.5 parts of polyether-polysiloxane D (subscript c=10, d=10, e=5, R is methyl) and 11 parts of alkynyl alcohol polyether E (subscript f=8, g=3, R is methyl) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-51 of the ink system is obtained.

[0101] Comparative Example 6:

[0102] Preparation of DF-52 defoaming composition for ink systems (by replacing the weak alkaline catalyst with a strong alkaline catalyst).

[0103] The first step involves adding 40 parts of modified polysiloxane A3, 0.5 parts of potassium hydroxide catalyst, and 2 parts of precipitated hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 123℃, and vigorously sheared and mixed at 3800rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 3MPa to disperse the silica into particles of 780nm.

[0104] The second step involves adding 43.5 parts of polyether-polysiloxane D (subscript c=10, d=10, e=5, R is methyl) and 11 parts of alkynyl alcohol polyether E (subscript f=8, g=3, R is methyl) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-52 of the ink system is obtained.

[0105] Comparative Example 7:

[0106] Preparation of DF-53, an antifoaming composition for ink systems (with only polyether-polysiloxane copolymer added).

[0107] The first step involves adding 40 parts of modified polysiloxane A3, 0.5 parts of catalyst monoethanolamine, and 2 parts of precipitated hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 123℃, and vigorously sheared and mixed at 3800rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 3MPa to disperse the silica into particles of 780nm.

[0108] The second step involves adding 54.5 parts of polyether-polysiloxane D (subscripts c=10, d=10, e=5, R is methyl) to the mixture obtained in the first step and mixing thoroughly to obtain the ink system defoaming composition DF-53.

[0109] Comparative Example 8:

[0110] Preparation of DF-54, an antifoaming composition for ink systems (with only alkynyl alcohol polyether added).

[0111] The first step involves adding 40 parts of modified polysiloxane A3, 0.5 parts of catalyst monoethanolamine, and 2 parts of precipitated hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 123℃, and vigorously sheared and mixed at 3800rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 3MPa to disperse the silica into particles of 780nm.

[0112] The second step involves adding 54.5 parts of acetylacetonate polyether E (subscript f = 8, g = 3, R) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-54 of the ink system is obtained.

[0113] Comparative Example 9:

[0114] Preparation of DF-55 defoaming composition for ink systems (using only alkynyl alcohol polyether and polyether-polysiloxane copolymer)

[0115] Add 43.5 parts of polyether-polysiloxane D (subscript c=10, d=10, e=5, R is methyl) and 11 parts of alkynyl alcohol polyether E (subscript f=8, g=3, R is methyl) to a container. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-55 of the ink system is obtained.

[0116] Comparative Example 10:

[0117] Preparation of DF-56, an antifoaming composition for ink systems (without alkynyl alcohol polyether and polyether-polysiloxane copolymer).

[0118] Add 40 parts of modified polysiloxane A3, 0.5 parts of catalyst monoethanolamine, and 2 parts of precipitated hydrophobic silica (specific surface area of ​​110 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heat to 123℃, maintain a speed of 3800rpm for strong shear mixing for 3.5h, and finally process with a homogenizer under a pressure of 3MPa to disperse silica into 780nm particles to obtain ink system defoaming composition DF-56.

[0119] Comparative Example 11:

[0120] Preparation of DF-57 defoaming composition for ink systems (using only one type of silica)

[0121] The first step involves adding 40 parts of modified polysiloxane A3, 0.5 parts of catalyst monoethanolamine, and 5 parts of precipitated hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 After heating to 123°C, the mixture was subjected to intense shearing and mixing at 3800 rpm for 3.5 hours. Finally, it was homogenized under a pressure of 3 MPa to disperse the silica into 780 nm particles.

[0122] The second step involves adding 43.5 parts of polyether-polysiloxane D (subscript c=10, d=10, e=5, R is methyl) and 11 parts of alkynyl alcohol polyether E (subscript f=8, g=3, R is methyl) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-57 of the ink system is obtained.

[0123] Comparative Example 12:

[0124] Preparation of DF-58 defoaming composition for ink system (the specific surface area difference between the two silicas is less than 80).

[0125] The first step involves adding 40 parts of modified polysiloxane A3, 0.5 parts of catalyst monoethanolamine, and 2 parts of precipitated hydrophobic silica (with a specific surface area of ​​200 m²) to a container. 2 / g) and 3 parts of fumed hydrophobic silica (specific surface area of ​​250m²) 2 / g), heated to 123℃, and vigorously sheared and mixed at 3800rpm for 3.5h. Finally, it was treated with a homogenizer under a pressure of 3MPa to disperse the silica into particles of 780nm.

[0126] The second step involves adding 43.5 parts of polyether-polysiloxane D (subscript c=10, d=10, e=5, R is methyl) and 11 parts of alkynyl alcohol polyether E (subscript f=8, g=3, R is methyl) to the mixture obtained in the first step. 1 When hydrogen atoms are mixed evenly, the defoaming composition DF-58 of the ink system is obtained.

[0127] Example 11:

[0128] Preparation of DF-6 defoaming composition for ink systems

[0129] The first step involves adding 5 parts of modified polysiloxane A1, 15 parts of modified polysiloxane A1, 0.5 parts of the catalyst triethanolamine, and 1 part of precipitated hydrophobic silica (with a specific surface area of ​​110 m²) to a container. 2 / g) and 5 parts of fumed hydrophobic silica (specific surface area of ​​380m²) 2 / g), heated to 145℃, and vigorously sheared and mixed at 2500rpm for 6h. Finally, it was treated with a homogenizer under a pressure of 4.5MPa to disperse the silica into particles of 800nm.

[0130] The second step involves adding 20 parts of polyether-polysiloxane (subscript c=5, d=9, e=0, R is methyl), 25.5 parts of polyether-polysiloxane (subscript c=17, d=8, e=4, R is methyl), and 15 parts of alkynyl alcohol polyether (subscript f=2, g=5, R is methyl) to the mixture obtained in the first step. 1(for hydrogen atoms), 13 parts alkynyl alcohol polyether E (subscript f=7, g=7, R) 1 When the methyl atoms are mixed evenly, the defoaming composition DF-6 of the ink system is obtained.

[0131] Example 12:

[0132] Raw materials required for E-5 defoamer in emulsion ink systems:

[0133]

[0134]

[0135] At room temperature, ink defoamer composition DF-5, fatty alcohol polyoxyethylene ether (3) and fatty alcohol polyoxyethylene ether (9) were added to a container. The rotation speed was set to 2000 rpm. The designed amount of water was added within 40 minutes and then processed through a homogenizer to control the emulsion particle size to below 5 μm. Finally, acrylic thickener and preservative Kathon were added to the emulsion, and the pH value of the emulsion was adjusted to 7.5 to obtain emulsion-type ink system defoamer E-5.

[0136] The performance of the defoaming composition of the ink system prepared by the method of the present invention is mainly evaluated from the following aspects:

[0137] 1. Compatibility test:

[0138] Weigh 250g of commercially available water-based ink (composed of acrylic resin and red pigment) and 0.2g of the test sample (with the same 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 above dispersion and drop it onto black and white paper. Use a 40μm wire rod to scrape it evenly at a constant speed and observe the state of the dispersion on the black and white paper (porosity). The results are shown in Table 1.

[0139] 2. Foam control performance:

[0140] 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.

[0141] Table 1. Test results of compatibility and foam control performance.

[0142]

[0143]

[0144] The data above shows that:

[0145] The defoaming compositions of ink systems prepared using the patented components, whether the original solutions DF-1 to DF-6 or the emulsion E-1, all exhibit excellent compatibility and foam control performance.

[0146] Comparison reveals that the modified polysiloxanes prepared using tris(trimethylsiloxyvinylsilane) and xylitol allyl ether exhibit better performance, while the modified polysiloxanes obtained by removing tris(trimethylsiloxyvinylsilane) or xylitol allyl ether, namely DF-41 and DF-42, show poor performance. This indicates that there is a synergistic effect between tris(trimethylsiloxyvinylsilane) and xylitol allyl ether.

[0147] The defoaming compositions DF-51 and DF-52 of the ink system indicate that only weak bases can be used for catalysis in the system of the patented invention. During the experiment, it was also found that the viscosity of the composition obtained by strong base catalysis was significantly higher, which may be due to some silicon-hydrogen bonds undergoing cross-linking reaction under strong base conditions.

[0148] The experimental results of the ink system defoaming compositions DF-53 to DF-54 indicate that there is a compatibility and synergistic effect between polyether-polysiloxane and alkynyl alcohol polyether. DF-55 is a sample prepared using only polyether-polysiloxane and alkynyl alcohol polyether. It has good compatibility but poor defoaming effect. DF-56 has good defoaming effect but poor compatibility. This further illustrates that there is an interaction between the polyether-polysiloxane and alkynyl alcohol polyether combination and the modified polysiloxane.

[0149] The results of comparing DF-5 with DF-57 and DF-58 show that the difference in specific surface area between using one type of silica and using two types does not exceed 80 m². 2 When the concentration of silica is / g, the compatibility of the defoaming composition with the ink is not affected, but the foam control time is slightly worse.

Claims

1. A defoamer composition for an ink system, characterized in that, It is prepared from modified polysiloxane A, silica B, catalyst C, polyether-polysiloxane copolymer D, and alkynyl alcohol polyether E: A. Modified polysiloxane, wherein the modified polysiloxane is obtained by hydrosilylation reaction of hydrogen-containing polysiloxane, tris(trimethylsiloxy)vinylsilane, and xylitol allyl ether under the action of chloroplatinic acid; The structural formula of the hydrogen-containing polysiloxane used in the preparation of the modified polysiloxane is as follows: In formula (Ⅰ), the subscripts a and b represent the average degree of polymerization of the two repeating units. The dynamic viscosity of the hydrogen-containing polysiloxane at 25°C is 5–30 mPa·s, and the hydrogen content is 0.1–1.2%. The raw materials used to prepare the modified polysiloxane are as follows (by weight percentage): The sum of the mass percentages of the above substances is 100%; The modified polysiloxane is prepared as follows: hydrogen-containing polysiloxane and tris(trimethylsiloxy)vinylsilane are added to a flask, stirring is started and the temperature is raised. When the temperature reaches 60-80°C, 1-2 ppm of chloroplatinic acid catalyst is added and the temperature is maintained for 10-30 min. Then xylitol allyl ether and the remaining chloroplatinic acid catalyst are added, and the temperature is raised to 100-140°C and maintained until the product in the flask becomes transparent. The product is then cooled to room temperature to obtain the modified polysiloxane. The amount of the modified polysiloxane used is 10-60% of the total mass of the defoaming composition of the ink system; B. Silica, wherein the silica has a specific surface area of ​​50–200 m². 2 / g and specific surface area 250-500m² 2 A composition of two hydrophobic silicas with different specific surface areas per g, wherein the difference in their specific surface areas is greater than 80 m². 2 / g; The amount of silica used is 3-20% of the total mass of the defoaming composition in the ink system; C. Catalyst, wherein the catalyst is selected from sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium acetate, monoethanolamine, diethanolamine and triethanolamine; The amount of the catalyst used is 0.1% to 2% of the total mass of the defoaming composition in the ink system; D. Polyether-polysiloxane copolymer The polyether-polysiloxane copolymer has the following structural formula: In formula (II), the subscript c takes values ​​from 5 to 20, the subscripts d and e are the average degree of polymerization of ethylene oxide (EO) and propylene oxide (PO), respectively, d is 1 to 15, and e is 0 or 1 to 15; R is selected from methyl, ethyl, propyl, butyl, and acetyl end-capping groups; The amount of the polyether-polysiloxane copolymer used is 20-60% of the total mass of the ink system defoaming composition; E. Acynyl alcohol polyether, wherein the general structural formula of the acynyl alcohol polyether is as follows: In formula (Ⅲ), the subscripts f and g represent the degree of polymerization of ethylene oxide (EO) and propylene oxide (PO), and the average values ​​of f and g are 1 to 10; R 1 It is an alkyl group with 1 to 6 hydrogen atoms and carbon atoms; The amount of the acetylacetonate polyether used is 10-30% of the total mass of the defoaming composition of the ink system; The total mass percentage of the raw materials used in preparing the defoaming composition of the ink system is 100%. The preparation method of the defoaming composition of the ink system is as follows: The first step is to add modified polysiloxane A, silica B and catalyst C to a container, heat to 100-150°C, and mix vigorously at a speed of 2000-5000 rpm for 2-6 hours. Finally, the mixture is treated with a homogenizer under a pressure of 1-10 MPa to disperse silica B into particles smaller than 1000 nm. The second step involves adding polyether-polysiloxane D and alkynyl alcohol polyether E to the mixture obtained in the first step and mixing them evenly to obtain the ink system defoaming composition.

2. The defoaming composition for an ink system according to claim 1, characterized in that, The hydrophobic material on the silica surface 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.

3. The defoaming composition for an ink system according to claim 1, characterized in that, The defoaming composition of the ink system is prepared as an emulsion using emulsifiers, water, thickeners, and preservatives. The mass percentages of the raw materials used to prepare the emulsion are as follows: The total mass percentage of all raw materials used in preparing the emulsion is 100%. The emulsifier is a nonionic surfactant selected from one or more of the following: nonanoic 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, sorbitan trifatty acid ester polyoxyethylene ether, and castor oil polyoxyethylene ether. The thickener is selected from one or more of polyvinyl alcohol, carbomer, xanthan gum, cellulose ethers, polyacrylates and polyacrylamide; The water mentioned is clean water used in industrial production processes or ice in solid form; 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-nitropropionamide, 2-bromo-2-nitro-1,3-propanediol, potassium sorbate, p-hydroxybenzoate, sodium lactate, and sodium benzoate.

4. The defoaming composition for an emulsion-type ink system according to claim 3, characterized in that, The preparation method of the defoamer for the emulsion-type ink system is as follows: At room temperature, add the ink defoamer composition and emulsifier to the container, set the rotation speed to 1000-3000 rpm, add the designed amount of water within 20-50 minutes, and then process it through a homogenizer to control the emulsion particle size to 1-5 μm. Finally, add thickener and preservative to the emulsion to obtain the emulsion-type ink system defoamer.

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