Efficient organic silicon defoaming agent suitable for metal working fluid as well as preparation method and application of efficient organic silicon defoaming agent

Abstract

The invention provides an efficient organic silicon defoaming agent suitable for metal working fluid as well as a preparation method and application of the efficient organic silicon defoaming agent. The defoaming agent is prepared from low-molecular-weight naphthenic base modified polydimethylsiloxane, a nonionic emulsifier, a zwitterionic emulsifier, a surface activity regulator, an anti-foaming layer enhancer and a high-temperature-resistant additive, the high-efficiency defoaming agent suitable for the metal working fluid is developed by designing an organic silicon defoaming agent taking low-molecular-weight naphthenic base modified polydimethylsiloxane as a core and adopting a composite emulsification system and a functional auxiliary agent as auxiliary materials, so that the stability and rapid defoaming performance under high-temperature and high-shear conditions are ensured, and the working condition requirements of modern working fluid are met.

Description

Technical Field

[0001] The present application relates to the technical field of defoamers, and in particular to a high-efficiency organosilicon defoamer suitable for metalworking fluids, a preparation method thereof, and an application thereof. Background Art

[0002] Metalworking fluid, also known as metal cutting fluid or metal coolant, plays an important role in cooling, lubricating, rust prevention and cleaning during metal processing. However, during the circulation and high-speed stirring of the liquid, a large amount of foam is easily formed due to the mixing of air and the action of surfactants. The generation of foam not only affects the cooling and lubricating properties of the processing fluid, but also causes unstable operation of the pump system, misjudgment of the liquid level and equipment failure, reducing processing efficiency and product quality.

[0003] Existing metalworking fluid defoamers are mainly mineral oil, ester or silicone oil modified products, but there are problems such as foam regeneration, poor system compatibility, impact on metal surface quality and high temperature failure. Foam regeneration: After rapid defoaming, traditional defoamers have insufficient foam suppression persistence, and foam is prone to repeated generation, requiring frequent addition of defoamers. Poor system compatibility: Mineral oil defoamers are prone to stratification or oil stains in aqueous metalworking fluids, affecting the transparency and performance of the processing fluid. Impact on metal surface quality: Some defoamers may form residues on the metal surface, resulting in a decrease in the quality of subsequent coating or welding. High temperature failure: Many defoamers are unstable under high temperature and high shear conditions, and it is difficult to meet the stringent requirements of modern metalworking fluids for defoamers.

[0004] With the rapid development of modern industry, the performance requirements for metalworking fluids are increasing. An efficient and environmentally friendly defoamer with high defoaming efficiency, good foam suppression and no negative impact on the performance of the processing fluid is needed to meet the needs under complex working conditions. Summary of the invention

[0005] The present application provides a high-efficiency organosilicon defoamer suitable for metalworking fluids and a preparation method and application thereof to solve the problems existing in the related technologies. The technical solution is as follows:

[0006] In a first aspect, the present application provides an efficient organosilicon defoamer suitable for metalworking fluids, comprising the following raw materials in parts by weight:

[0007]

[0008] In one embodiment, the low molecular weight cycloalkyl modified polydimethylsiloxane is prepared by introducing cycloalkyl side groups into the siloxane main chain, and the structural formula of the low molecular weight cycloalkyl modified polydimethylsiloxane is:

[0009] (CH 3 )3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ;

[0010] R 1 is a cycloalkyl group; preferably, R 1 It is cyclopentyl, cyclohexyl, cycloheptyl; the ratio of m / n is 1:1 to 1:10; m=1-50, n=10-100, and m and n are integers.

[0011] In one embodiment, the low molecular weight cycloalkyl modified polydimethylsiloxane is prepared by the following method:

[0012] Octamethylcyclotetrasiloxane and cycloalkylmethyldimethoxysilane are subjected to ring-opening polymerization in the presence of a catalyst; after the polymerization reaction is completed, hexamethyldisiloxane is used to end-cap and terminate the reaction; and low molecular weight cycloalkyl modified polydimethylsiloxane is obtained after separation. In one embodiment, the nonionic emulsifier is fatty alcohol polyoxyethylene ether, and the structural formula is:

[0013] R 2 -(OCH 2 CH 2 ) o -OH;

[0014] R 2 It is a C10-C18 long-chain alkyl or phenyl group; o=3-25, and o is an integer.

[0015] In one embodiment, the zwitterionic emulsifier is an alkyl betaine, and the structural formula is:

[0016] R 3 -N + (CH 3 ) 2 CH 2 COO - ;

[0017] R 3 It is a C10-C18 long chain alkyl group.

[0018] In one embodiment, the surfactant is a fluorine-modified polyether having the structural formula:

[0019] CF 3 (CF 2 ) p CH 2 CH2 O(CH 2 CH 2 O) q H;

[0020] p=3-7, q=5-15, and p and q are integers.

[0021] In one embodiment, the anti-foaming layer reinforcing agent is a vinyl-containing modified siloxane; the structural formula is:

[0022] (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ;

[0023] y=10-60, and y is an integer.

[0024] In one embodiment, the high temperature resistant additive is a high temperature resistant fatty acid ester; the structural formula is:

[0025] R 4 COO(CH 2 CH 2 O) x H;

[0026] R 4 It is a C16-C18 long chain alkyl group, x=10-20, and x is an integer.

[0027] In a second aspect, the present application provides a method for preparing a high-efficiency organosilicon defoamer suitable for metalworking fluids, comprising the following steps:

[0028] Step S1, adding a nonionic emulsifier and a zwitterionic emulsifier to a low molecular weight cycloalkyl modified polydimethylsiloxane in a flowing state under stirring, and stirring evenly; slowly heating and keeping the temperature to form a stable emulsified system;

[0029] Step S2, adding a surfactant regulator, an anti-foaming layer enhancer and a high temperature resistance additive to the emulsified system in sequence, stirring after each addition to mix evenly;

[0030] Step S3, after the mixing is completed, continue stirring and slowly cool down, filter, and obtain the high-efficiency organosilicon defoamer suitable for metalworking fluid.

[0031] In one embodiment, in step S1, the nonionic emulsifier is preliminarily dissolved at room temperature; the stirring rate is 500-1000 rpm; the low molecular weight cycloalkyl modified polydimethylsiloxane is heated to 40-50°C to achieve a fluid state; the temperature is slowly raised to 60-70°C and kept warm for 5-10 minutes.

[0032] In one embodiment, the stirring rate in step S2 is 700-1200 rpm; and the stirring time is 10-15 min.

[0033] In one embodiment, in step S3, the temperature is lowered to room temperature.

[0034] In a third aspect, the embodiments of the present application provide an application of the above-mentioned high-efficiency silicone defoaming agent suitable for metalworking fluids in aqueous cutting fluids, oily grinding fluids, and high-temperature and high-speed cutting fluids.

[0035] The advantages or beneficial effects of the above technical solution include at least:

[0036] The high-efficiency organosilicon defoamer suitable for metalworking fluids of the present application is developed by designing an organosilicon defoamer with a low molecular weight cycloalkyl modified polydimethylsiloxane as the core, supplemented by a composite emulsification system and functional additives, to ensure stability and rapid defoaming performance under high temperature and high shear conditions, and to meet the requirements of modern processing fluid working conditions.

[0037] The above summary is for the purpose of description only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent through the following detailed description. DETAILED DESCRIPTION

[0038] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the description is considered to be exemplary rather than restrictive in nature.

[0039] The defoamer for metalworking fluid is required to have fast defoaming and long-term anti-foaming performance, and have no negative impact on the lubricity, cooling and stability of the metalworking fluid. However, the existing defoamers have problems such as foam regeneration, poor system compatibility, affecting the metal surface quality and high-temperature failure. Therefore, in order to overcome the above problems and make the defoamer meet the use of metalworking fluid, the present application provides a high-efficiency silicone defoamer suitable for metalworking fluid, including the following raw materials in parts by weight:

[0040]

[0041] Selecting low molecular weight polydimethylsiloxane can ensure stability and rapid defoaming performance under high shear conditions; using cycloalkyl to modify it can enhance the dispersibility and antifoaming durability of silicone and prevent the defoamer from agglomerating or precipitating in the liquid; and the composite emulsification system of non-ionic emulsifier and zwitterionic emulsifier can improve the dispersibility of the defoamer in aqueous metalworking fluid to prevent oil spots or stratification problems; enhance the stability of the defoamer under hard water conditions to avoid emulsification failure. The use of surfactant regulators and anti-foaming layer enhancers can reduce the surface tension of the processing fluid, accelerate the diffusion of the defoamer to the gas-liquid interface, and form a stable anti-foaming layer after the foam breaks to prevent foam regeneration; anti-high temperature additives can ensure the long-lasting performance of the defoamer under high temperature and high shear conditions to meet the requirements of modern processing fluid working conditions.

[0042] In one embodiment, the low molecular weight cycloalkyl modified polydimethylsiloxane is prepared by introducing cycloalkyl side groups into the siloxane main chain, and the structural formula of the low molecular weight cycloalkyl modified polydimethylsiloxane is:

[0043] (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ;

[0044] R 1 is a cycloalkyl group; preferably, R 1 It is cyclopentyl, cyclohexyl, cycloheptyl; the ratio of m / n is 1:1 to 1:10; m=1-50, n=10-100, and m and n are integers.

[0045] Low molecular weight cycloalkyl modified polydimethylsiloxane is used as the core component, and cycloalkyl side groups are introduced into the main chain of siloxane. Its unique molecular structure gives it the ability to diffuse quickly to the gas-liquid interface, which can quickly destroy the bubble film layer and cause the bubble to collapse, achieving excellent rapid defoaming effect, and can enhance the dispersibility and anti-foaming durability of silicone, preventing the defoaming agent from agglomerating or precipitating in the liquid.

[0046] In one embodiment, the low molecular weight cycloalkyl modified polydimethylsiloxane is prepared by the following method:

[0047] Octamethylcyclotetrasiloxane and cycloalkylmethyldimethoxysilane undergo a ring-opening polymerization reaction in the presence of a catalyst; after the polymerization reaction is completed, hexamethyldisiloxane is used for end-capping to terminate the reaction; and low molecular weight cycloalkyl modified polydimethylsiloxane is obtained after separation.

[0048] In one embodiment, the molar ratio of octamethylcyclotetrasiloxane to cycloalkylmethyldimethoxysilane is m / 4:n.

[0049] In one embodiment, the catalyst is KOH, and the mass concentration of the catalyst is 0.1%-0.5%.

[0050] In one embodiment, the ring-opening polymerization reaction conditions are: under nitrogen protection, 80-100° C. for 4-8 hours.

[0051] In one embodiment, hexamethyldisiloxane is added as a capping agent, and the reaction is continued for 1-2 hours; acetic acid is added with a mass concentration of 0.1-0.5% to terminate the reaction.

[0052] In one embodiment, after the reaction is completed, unreacted monomers and low-boiling point by-products are removed by distillation under reduced pressure.

[0053] In one embodiment, the polymer is washed with an organic solvent and dried to obtain pure low molecular weight cycloalkyl-modified polydimethylsiloxane.

[0054] In one embodiment, octamethylcyclotetrasiloxane and cycloalkylmethyldimethoxysilane are added to a reactor in a molar ratio of m / 4:n; KOH is added to make the mass concentration of sodium hydroxide 0.1%-0.5%; the reaction is carried out at 80-100° C. for 4-8 hours under nitrogen protection; and a ring-opening polymerization reaction is carried out;

[0055] After the polymerization reaction is completed, hexamethyldisiloxane is added as a capping agent and the reaction is continued for 1-2 hours; acetic acid is added to a mass concentration of 0.1-0.5% to terminate the reaction;

[0056] After the reaction was completed, unreacted monomers and low-boiling point by-products were removed by distillation under reduced pressure.

[0057] The polymer is washed with an organic solvent and dried to obtain pure low molecular weight cycloalkyl-modified polydimethylsiloxane.

[0058] In one embodiment, the cycloalkylmethyldimethoxysilane is one of cyclopentylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane or cycloheptylmethyldimethoxysilane. In one embodiment, the nonionic emulsifier is fatty alcohol polyoxyethylene ether, and the structural formula is:

[0059] R 2 -(OCH 2 CH 2 ) o -OH;

[0060] R 2It is a C10-C18 long-chain alkyl or phenyl group; o=3-25, and o is an integer.

[0061] Nonionic emulsifiers can improve the dispersibility of defoamers in aqueous metalworking fluids to prevent oil spots or stratification problems.

[0062] In one embodiment, the zwitterionic emulsifier is an alkyl betaine, and the structural formula is:

[0063] R 3 -N + (CH 3 ) 2 CH 2 COO - ;

[0064] R 3 It is a C10-C18 long chain alkyl group.

[0065] Zwitterionic emulsifiers can enhance the stability of defoamers in hard water conditions and avoid emulsification failure.

[0066] The composite emulsification system composed of nonionic emulsifier and zwitterionic emulsifier can form a stable microemulsion structure in the liquid, inhibiting the formation of bubble nuclei. The anti-foam layer enhancer further inhibits the proliferation and diffusion of foam by forming a high-strength protective film at the gas-liquid interface. The two work together to significantly extend the anti-foaming time and meet the long-term process requirements.

[0067] In one embodiment, the surfactant is a fluorine-modified polyether having the structural formula:

[0068] CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H;

[0069] p=3-7, q=5-15, and p and q are integers.

[0070] In one embodiment, the anti-foaming layer reinforcing agent is a vinyl-containing modified siloxane; the structural formula is:

[0071] (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ;

[0072] y=10-60, and y is an integer.

[0073] The use of fluorine-modified polyether as a surfactant regulator and vinyl-containing modified siloxane as an anti-foaming layer enhancer can ensure the uniform distribution of active ingredients in different matrices and maintain the physical and chemical properties of metalworking fluids. The distribution efficiency of the defoamer on the interface is optimized, thereby enhancing the overall defoaming speed. This makes the defoamer have excellent compatibility and can show good dispersibility in both aqueous and oily metalworking fluids, without affecting the transparency and lubricity of the system, and without forming solid residues.

[0074] In one embodiment, the high temperature resistant additive is a high temperature resistant fatty acid ester; the structural formula is:

[0075] R 4 COO(CH 2 CH 2 O) x H;

[0076] R 4 It is a C16-C18 long chain alkyl group, x=10-20, and x is an integer.

[0077] The high temperature resistant additive of the present application is a fatty acid ester with a long-chain alkyl and polyethylene glycol structure, which enhances the thermal stability and shear stability of the molecular chain, and can still maintain stable performance under high temperature and high shear conditions, ensuring the continued effectiveness of the defoamer under harsh working conditions. The synergistic effect with the defoaming core component enables the product to be widely used in high temperature metal processing, petrochemical industry and other harsh operating environments.

[0078] The present application also provides a method for preparing a high-efficiency organosilicon defoamer suitable for metalworking fluids, comprising the following steps:

[0079] Step S1, adding a nonionic emulsifier and a zwitterionic emulsifier to a low molecular weight cycloalkyl modified polydimethylsiloxane in a flowing state under stirring, and stirring evenly; slowly heating and keeping the temperature to form a stable emulsified system;

[0080] Step S2, adding a surfactant regulator, an anti-foaming layer enhancer and a high temperature resistance additive to the emulsified system in sequence, stirring after each addition to mix evenly;

[0081] Step S3, after the mixing is completed, continue stirring and slowly cool down, filter, and obtain the high-efficiency organosilicon defoamer suitable for metalworking fluid.

[0082] In one embodiment, in step S1, the nonionic emulsifier is preliminarily dissolved at room temperature; the stirring rate is 500-1000 rpm; the low molecular weight cycloalkyl modified polydimethylsiloxane is heated to 40-50°C to achieve a fluid state; the temperature is slowly raised to 60-70°C and kept warm for 5-10 minutes.

[0083] The nonionic emulsifier is dissolved in advance, and the low molecular weight cycloalkyl modified polydimethylsiloxane is mixed with each other to achieve a fluid state to ensure uniform mixing.

[0084] In one embodiment, the stirring rate in step S2 is 700-1200 rpm, and the stirring time is 10-15 min. The stirring speed is controlled to be moderate 700-1200 rpm to avoid bubble generation.

[0085] In one embodiment, in step S3, the temperature is lowered to room temperature. After the mixing is completed, the temperature is slowly lowered to room temperature while continuing to stir to prevent the components from stratifying; the final product is filtered to remove possible impurities or incompletely dissolved particles.

[0086] The following is a further description with reference to specific embodiments.

[0087] Example 1

[0088] In parts by weight, 75 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 12 parts of nonionic emulsifier, 8 parts of zwitterionic emulsifier, 8 parts of surfactant regulator, 3 parts of anti-foaming layer enhancer, and 2 parts of high temperature resistance additive;

[0089] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11), m=n=50; octamethylcyclotetrasiloxane and partially hydrolyzed cyclohexylmethyldimethoxysilane are added to the reactor in a molar ratio of 1:4; KOH is added to make the mass concentration of sodium hydroxide 0.3%; under nitrogen protection, react at 90°C for 6h; carry out ring-opening polymerization; after the polymerization reaction, hexamethyldisiloxane is added as a capping agent and the reaction is continued for 1.5h; acetic acid is added to make the mass concentration of acetic acid 0.3% to terminate the reaction; unreacted monomers and low-boiling point by-products are removed by reduced pressure distillation; the polymer is washed with an organic solvent and dried over anhydrous magnesium sulfate to obtain the above-mentioned low molecular weight cyclohexyl modified polydimethylsiloxane; the non-ionic emulsifier structure is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C16 alkyl group; o=10;

[0090] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C16 alkyl group;

[0091] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 5, q = 10;

[0092] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ; y = 40;

[0093] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=15;

[0094] Preparation steps:

[0095] A low molecular weight cycloalkyl modified polydimethylsiloxane is placed in a reaction kettle and heated to 40-50°C to make it flowable; at the same time, a nonionic emulsifier is stirred and pre-dissolved at room temperature, and under the condition of continuous stirring at 500-1000rpm, the nonionic emulsifier and the zwitterionic emulsifier are gradually added to the polydimethylsiloxane; after stirring evenly, the temperature is slowly raised to 60-70°C and maintained for 5-10min, and the two are fully mixed to form a stable emulsified system; a surfactant regulator, an anti-foaming layer enhancer and an anti-high temperature additive are added in sequence, and each addition is stirred for 10-15min to ensure that the components are evenly distributed; the stirring speed is controlled to 700-1200rpm to avoid bubble generation; after mixing, the temperature is slowly lowered to room temperature while continuing to stir to prevent the components from stratifying; the final product is filtered to remove possible impurities or incompletely dissolved particles, so as to obtain the high-efficiency silicone defoamer suitable for metalworking fluids.

[0096] Example 2

[0097] In parts by weight, 69 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 15 parts of nonionic emulsifier, 5 parts of zwitterionic emulsifier, 10 parts of surfactant regulator, 3 parts of anti-foaming layer enhancer, and 3 parts of high temperature resistance additive;

[0098] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclopentyl (C 5 H 9 ), m=10, n=100; octamethylcyclotetrasiloxane and partially hydrolyzed cyclopentylmethyldimethoxysilane are added to the reactor in a molar ratio of 1:40; KOH is added to make the mass concentration of sodium hydroxide 0.1%; under nitrogen protection, react at 80°C for 8h; carry out ring-opening polymerization; after the polymerization reaction is completed, hexamethyldisiloxane is added as a capping agent and the reaction is continued for 1h; acetic acid is added so that the mass concentration of acetic acid is 0.5% to terminate the reaction; unreacted monomers and low-boiling point by-products are removed by reduced pressure distillation; the polymer is washed with an organic solvent and dried over anhydrous magnesium sulfate to obtain the above-mentioned low molecular weight cyclopentyl modified polydimethylsiloxane;

[0099] The structure of nonionic emulsifier is R 2 -(OCH 2 CH 2) o -OH; R 2 is a C10 alkyl group; o=3;

[0100] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C18 alkyl group;

[0101] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 3, q ​​= 15;

[0102] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ; y = 10;

[0103] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C18 alkyl group, x=10;

[0104] The preparation method is the same as that in Example 1.

[0105] Example 3

[0106] In parts by weight, 60 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 13 parts of nonionic emulsifier, 10 parts of zwitterionic emulsifier, 7 parts of surfactant regulator, 2 parts of anti-foaming layer enhancer, and 5 parts of high temperature resistance additive;

[0107] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n-Si(CH 3 ) 3 ; R 1 Cycloheptyl (C 7 H 13 ), m=10, n=50; octamethylcyclotetrasiloxane and partially hydrolyzed cycloheptylmethyldimethoxysilane are added to the reactor in a molar ratio of 1:20; KOH is added to make the mass concentration of sodium hydroxide 0.5%; under nitrogen protection, react at 100°C for 4h; carry out ring-opening polymerization; after the polymerization reaction is completed, hexamethyldisiloxane is added as a capping agent and the reaction is continued for 2h; acetic acid is added to make the mass concentration of acetic acid 0.1% to terminate the reaction; unreacted monomers and low-boiling point by-products are removed by reduced pressure distillation; the polymer is washed with an organic solvent and dried over anhydrous magnesium sulfate to obtain the above-mentioned low molecular weight cycloheptyl modified polydimethylsiloxane;

[0108] The structure of nonionic emulsifier is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C18 alkyl group; o=25;

[0109] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C14 alkyl group;

[0110] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 4, q = 5;

[0111] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ;y=20;

[0112] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) xH; R 4 is a C18 alkyl group, x=20;

[0113] The preparation method is the same as that in Example 1.

[0114] Example 4

[0115] In parts by weight, 72 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 10 parts of nonionic emulsifier, 7 parts of zwitterionic emulsifier, 5 parts of surfactant regulator, 1 part of anti-foaming layer enhancer, and 4 parts of high temperature resistance additive;

[0116] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11 ), m=20, n=40; ​​octamethylcyclotetrasiloxane and partially hydrolyzed cyclohexylmethyldimethoxysilane were added to the reactor in a molar ratio of 1:8; KOH was added to make the mass concentration of sodium hydroxide 0.2%; the reaction was carried out at 95°C for 5 hours under nitrogen protection; a ring-opening polymerization reaction was carried out; after the polymerization reaction was completed, hexamethyldisiloxane was added as a capping agent and the reaction was continued for 1.5 hours; acetic acid was added to make the mass concentration of acetic acid 0.4% to terminate the reaction; unreacted monomers and low-boiling point by-products were removed by reduced pressure distillation; the polymer was washed with an organic solvent and dried over anhydrous magnesium sulfate to obtain the above-mentioned low molecular weight cyclohexyl modified polydimethylsiloxane; the non-ionic emulsifier structure is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C12 alkyl group; o=15;

[0117] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C10 alkyl group;

[0118] The surfactant structure is CF 3 (CF 2 )p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 7, q = 12;

[0119] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ;y=30;

[0120] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=15;

[0121] The preparation method is the same as that in Example 1.

[0122] Example 5

[0123] In parts by weight, 64 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 14 parts of nonionic emulsifier, 6 parts of zwitterionic emulsifier, 9 parts of surfactant regulator, 2 parts of anti-foaming layer enhancer, and 5 parts of high temperature resistance additive;

[0124] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11), m15, n=90; octamethylcyclotetrasiloxane and partially hydrolyzed cyclohexylmethyldimethoxysilane were added to the reactor in a molar ratio of 1:24; KOH was added to make the mass concentration of sodium hydroxide 0.4%; the reaction was carried out at 85°C for 7h under nitrogen protection; a ring-opening polymerization reaction was carried out; after the polymerization reaction was completed, hexamethyldisiloxane was added as a capping agent and the reaction was continued for 1.5h; acetic acid was added to make the mass concentration of acetic acid 0.2% to terminate the reaction; unreacted monomers and low-boiling point by-products were removed by reduced pressure distillation; the polymer was washed with an organic solvent and dried over anhydrous magnesium sulfate to obtain the above-mentioned low molecular weight cyclohexyl modified polydimethylsiloxane; the non-ionic emulsifier structure is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C14 alkyl group; o=20;

[0125] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C12 alkyl group;

[0126] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 6, q = 8;

[0127] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ; y = 60;

[0128] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=20;

[0129] The preparation method is the same as that in Example 1.

[0130] Comparative Example 1

[0131] In parts by weight, 75 parts of polydimethylsiloxane, 12 parts of nonionic emulsifier, 8 parts of zwitterionic emulsifier, 8 parts of surfactant regulator, 3 parts of anti-foaming layer enhancer, and 2 parts of high temperature resistance additive;

[0132] The structure of polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Methyl (-CH 3 ), m=n=50;

[0133] The structure of nonionic emulsifier is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C16 alkyl group; o=10;

[0134] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C16 alkyl group;

[0135] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 5, q = 10;

[0136] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ; y = 40;

[0137] The structure of high temperature resistant additive is R 4COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=15;

[0138] The preparation method is the same as that in Example 1.

[0139] Comparative Example 2

[0140] In parts by weight, 75 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 20 parts of nonionic emulsifier, 8 parts of surfactant regulator, 3 parts of anti-foaming layer enhancer, and 2 parts of high temperature resistance additive;

[0141] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11 ), m=n=50;

[0142] The structure of nonionic emulsifier is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C16 alkyl group; o=10;

[0143] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 5, q = 10;

[0144] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ; y = 40;

[0145] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=15;

[0146] The preparation method is the same as that in Example 1.

[0147] Comparative Example 3

[0148] In parts by weight, 75 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 20 parts of zwitterionic emulsifier, 8 parts of surfactant regulator, 3 parts of anti-foaming layer enhancer, and 2 parts of high temperature resistance additive;

[0149] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11 ), m=n=50;

[0150] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C16 alkyl group;

[0151] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O) q H; p = 5, q = 10;

[0152] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 )3 ; y = 40;

[0153] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=15;

[0154] The preparation method is the same as that in Example 1.

[0155] Comparative Example 4

[0156] In parts by weight, 75 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 12 parts of nonionic emulsifier, 8 parts of zwitterionic emulsifier, 8 parts of surfactant regulator, and 2 parts of high temperature resistance additive;

[0157] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11 ), m=n=50;

[0158] The structure of nonionic emulsifier is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C16 alkyl group; o=10;

[0159] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C16 alkyl group;

[0160] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2 O)q H; p = 5, q = 10;

[0161] The structure of high temperature resistant additive is R 4 COO(CH 2 CH 2 O) x H; R 4 is a C16 alkyl group, x=15;

[0162] The preparation method is the same as that in Example 1.

[0163] Comparative Example 5

[0164] In parts by weight, 75 parts of low molecular weight cycloalkyl modified polydimethylsiloxane, 12 parts of nonionic emulsifier, 8 parts of zwitterionic emulsifier, 8 parts of surfactant regulator, and 3 parts of anti-foaming layer enhancer;

[0165] The structure of low molecular weight cycloalkyl modified polydimethylsiloxane is (CH 3 ) 3 SiO-(Si(CH 3 ) 2 O) m -(Si(CH 3 )(R 1 )O) n -Si(CH 3 ) 3 ; R 1 Cyclohexyl (C 6 H 11 ), m=n=50;

[0166] The structure of nonionic emulsifier is R 2 -(OCH 2 CH 2 ) o -OH; R 2 is a C16 alkyl group; o=10;

[0167] Zwitterionic emulsifiers are alkane structures with R 3 -N + (CH 3 ) 2 CH 2 COO - ; R 3 is a C16 alkyl group;

[0168] The surfactant structure is CF 3 (CF 2 ) p CH 2 CH 2 O(CH 2 CH 2O) q H; p = 5, q = 10;

[0169] The structure of the anti-foam layer reinforcing agent is (CH 3 ) 3 SiO-[Si(CH 3 )(CH=CH 2 )O] y -Si(CH 3 ) 3 ; y = 40;

[0170] The preparation method is the same as that in Example 1.

[0171] Test condition settings:

[0172] 1. Place the water-based cutting fluid in the circulation system, set the speed of the circulation pump to 3000rpm, and control the temperature at 50℃; the composition of the water-based cutting fluid is: 8% polyoxyethylene alcohol ester; 8% carboxylate; 15% borate; 3% OP-10; 2% ethylene glycol butyl ether; 64% water;

[0173] Add defoamer: add defoamer at 0.1% of the total mass of the cutting fluid; mix evenly with a stirrer;

[0174] Data Records:

[0175] Use a standard foam measuring instrument to record the initial value of the foam height. Record the foam height every 10 seconds until the foam disappears completely. Observe for 120 minutes and record whether the foam is regenerated. The results are shown in Table 1:

[0176] Table 1 Defoaming performance in water-based cutting fluid

[0177]

[0178]

[0179] As can be seen from Table 1, Comparative Example 1 uses polydimethylsiloxane as the base component and has not been modified by cycloalkane. The defoaming performance is significantly reduced. It takes twice as long to eliminate the foam to less than 5 mm, and the foam regenerates within 90 minutes, requiring repeated addition of defoaming agent. Comparative Examples 2 and 3 do not use a composite emulsifier, but only a single emulsifier. The defoaming rate is lower than that of Example 1. Comparative Example 4 does not contain an anti-foaming layer enhancer. After the first 10 seconds, as the defoaming progresses, the defoaming efficiency per unit time is low. This is because without an anti-foaming layer enhancer, the foam regenerates while it is broken, resulting in a decrease in the defoaming efficiency. Comparative Example 5 does not contain an anti-high temperature additive. At 50°C, the effect of temperature is not very obvious in the early stage, but as the defoaming agent stays in a high temperature environment, the defoaming performance is gradually affected and decreases.

[0180] 2. The oily grinding fluid is placed in a circulation system, the circulation pump speed is set to 4000 rpm, and the temperature is controlled at 80°C; the oily grinding fluid composition is: base oil (synthetic oil) 70%; extreme pressure additive (sulfurized fatty acid ester) 15%; anti-wear agent (boric acid ester) 6%; rust inhibitor (benzotriazole derivative) 6%; antioxidant (fatty amine) 3%.

[0181] Add defoamer: add defoamer at 0.05% of the total mass of the cutting fluid; mix evenly with a stirrer;

[0182] Data Records:

[0183] Use a standard foam measuring instrument to record the initial value of the foam height. Record the foam height every 15 seconds until the foam disappears completely. The results are shown in Table 2:

[0184] Table 2 Defoaming performance of oily grinding fluid under high temperature and high shear

[0185]

[0186] As can be seen from Table 2, Example 1 and Comparative Examples 1-4 exhibit similar defoaming properties as those in aqueous cutting fluids. However, it should be noted that Comparative Example 5 does not contain an anti-high temperature additive, and at 80°C, the temperature exhibits a strong influence, especially as the defoaming agent stays in a high temperature environment, the defoaming performance decreases significantly, the defoaming ability gradually decreases, and even within the observation time, the foam is not completely eliminated.

[0187] In summary, this application has developed a highly efficient silicone defoamer with rapid defoaming, long-term foam suppression, excellent compatibility and environmental protection in response to the special needs of metalworking fluids. Through a series of experimental verifications, the defoamer of the present invention can significantly improve the performance of metalworking fluids, effectively reduce equipment failure rates and energy consumption, and provide an efficient solution for the metalworking industry.

[0188] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0189] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0190] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. High-efficiency silicone defoamer suitable for metalworking fluids, characterized by: The invention comprises the following raw materials in parts by weight:

2. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 1, characterized in that: The low molecular weight cycloalkyl modified polydimethylsiloxane is prepared by introducing cycloalkyl side groups into the main chain of siloxane. The structural formula of the low molecular weight cycloalkyl modified polydimethylsiloxane is: <h2 style=";text-align:left;direction:ltr">(CH3)3SiO-(Si(CH3)2O)<h2 style=";text-align:left;direction:ltr"> m <h2 style=";text-align:left;direction:ltr"> -(Si(CH3)(R1)O)<h2 style=";text-align:left;direction:ltr"> n <h2 style=";text-align:left;direction:ltr"> -Si(CH3)3; R1 is a cycloalkyl group; preferably, R1 is a cyclopentyl group, a cyclohexyl group, or a cycloheptyl group; the ratio of m / n is 1:1 to 1:10; m=1-50, n=10-100, and m and n are integers.

3. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 2, characterized in that: The low molecular weight cycloalkyl modified polydimethylsiloxane is prepared by the following method: Octamethylcyclotetrasiloxane and cycloalkylmethyldimethoxysilane undergo a ring-opening polymerization reaction in the presence of a catalyst; after the polymerization reaction is completed, hexamethyldisiloxane is used for end-capping to terminate the reaction; and low molecular weight cycloalkyl modified polydimethylsiloxane is obtained after separation.

4. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 1, characterized in that: The nonionic emulsifier is fatty alcohol polyoxyethylene ether, and the structural formula is: R2-(OCH2CH2) o -OH; R2 is a C10-C18 long-chain alkyl group or a phenyl group; o=3 to 25, and o is an integer.

5. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 1, characterized in that: The zwitterionic emulsifier is an alkyl betaine, and the structural formula is: R3-N + (CH3)2CH2COO - 4 R3 is a C10-C18 long chain alkyl group.

6. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 1, characterized in that: The surfactant is a fluorine-modified polyether, and the structural formula is: CF3(CF2) p CH2CH2O(CH2CH2O) q H; p=3-7, q=5-15, and p and q are integers.

7. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 1, characterized in that: The anti-foam layer reinforcing agent is a vinyl-containing modified siloxane; the structural formula is: (CH3)3SiO-[Si(CH3)(CH=CH2)O] y -Si(CH3)3; y=10-60, and y is an integer.

8. The high-efficiency organosilicon defoamer suitable for metalworking fluid according to claim 1, characterized in that: The high temperature resistant additive is a high temperature resistant fatty acid ester; the structural formula is: R4COO(CH2CH2O) x H; R4 is a C16-C18 long chain alkyl group, x=10-20, and x is an integer.

9. A method for preparing a high-efficiency organosilicon defoamer suitable for metalworking fluids, characterized in that: The following steps are involved: Step S1, adding a nonionic emulsifier and a zwitterionic emulsifier to a low molecular weight cycloalkyl modified polydimethylsiloxane in a flowing state under stirring, and stirring evenly; slowly heating and keeping the temperature to form a stable emulsified system; Step S2, adding a surfactant regulator, an anti-foaming layer enhancer and a high temperature resistance additive to the emulsified system in sequence, stirring after each addition to mix evenly; Step S3, after the mixing is completed, continue stirring and slowly cool down, filter, and obtain the high-efficiency organosilicon defoamer suitable for metalworking fluid.

10. Use of the high-efficiency organosilicon defoamer suitable for metalworking fluids according to any one of claims 1 to 9 in aqueous cutting fluids, oily grinding fluids, and high-temperature and high-speed cutting fluids.

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