Phosphorus-free pre-filming agent and pre-filming method

Abstract

The invention relates to the field of pre-filming, and discloses a non-phosphorus pre-filming agent and a pre-filming method, and the pre-filming agent comprises a reaction product of a compound as shown in a formula I and a compound as shown in a formula II, hydrolytic polymaleic anhydride and at least one azole compound. The pre-filming agent provided by the invention forms an obvious bluish violet film layer on the surface of an object to be pre-filmed, the color development time of titration of copper sulfate is obviously higher than the performance of more than 10s in the national standard HG / T3778-2005, and the pre-filming agent has few components, no phosphorus and no zinc, meets the current increasingly stringent pollutant discharge requirements, and has good application prospects. The problems of large discharge and large supplement after pre-filming of industrial enterprises and up-to-standard discharge of total phosphorus in discharged sewage are solved, and the method is particularly suitable for treatment of circulating cooling water with low-hardness and low-alkali water quality; # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of pre-filming, and in particular to a phosphorus-free pre-filming agent and a pre-filming method. Background Art

[0002] Pre-filming agents are often used when industrial circulating cooling water systems are newly started or started after maintenance and cleaning. Pre-filming is one of the important links in industrial water treatment technology and an important means to improve the corrosion resistance of circulating water equipment. At present, the commonly used pre-filming agents on the market are mostly composite agents of polyphosphate and zinc salt. Generally, the ratio of sodium hexametaphosphate to zinc sulfate heptahydrate is 4:1.6, the dosage is 400-800 mg / L, the pre-filming pH value is 5.5-6.5, and the pre-filming time is 12-48 hours. The above-mentioned pre-filming agents are used in large amounts, have high phosphorus content, and are prone to form calcium phosphate scale. A large amount of sewage discharge is required after pre-filming, and the discharged phosphorus has a great impact on the biochemical system in sewage treatment. In recent years, there have been new requirements for the standards for direct discharge of water pollutants, including GB 31570-2015 "Petroleum Refining Industry Pollutant Emission Standards" and GB 31571-2015 "Petrochemical Industry Pollutant Emission Standard Requirements". From July 1, 2017, the total phosphorus in the external water discharged by enterprises shall be ≤1.0mg / L, and the total zinc shall be ≤2.0mg / L. The total phosphorus limit for special emission areas is 0.5mg / L. The requirements for phosphorus and zinc emissions are increased. Therefore, the application of phosphorus-based pre-filming agents is restricted, and it is imperative to develop and apply phosphorus-free pre-filming agents. Summary of the invention

[0003] The purpose of the present invention is to overcome the above problems existing in the prior art and to provide a phosphorus-free pre-filming agent and a pre-filming method.

[0004] In order to achieve the above-mentioned object, the first aspect of the present invention provides a phosphorus-free pre-filming agent, wherein the pre-filming agent comprises a reaction product of a compound represented by formula I and a compound represented by formula II, hydrolyzed polymaleic anhydride and at least one azole compound;

[0005]

[0006] Wherein, R1 is sodium or potassium, R2 is R3, R4 and R5 are each independently selected from H or C1-C4 alkyl.

[0007] The second aspect of the present invention provides a pre-filming method, which comprises: contacting an object to be pre-filmed with the pre-filming agent in the presence of water.

[0008] Through the above technical scheme, the pre-filming agent provided by the present invention forms a distinct blue-purple film layer on the surface of the object to be pre-filmed, and the color development time of copper sulfate titration is significantly higher than the performance of more than 10s in the national standard HG / T3778-2005, and the pre-filming agent has fewer components, is phosphorus-free and zinc-free, and meets the increasingly stringent pollutant emission requirements. It solves the problem of large-scale discharge and replenishment of industrial enterprises after pre-filming and the discharge of total phosphorus in the discharged wastewater meeting the emission standards, and is particularly suitable for circulating cooling water treatment with low hardness and low alkali water quality. DETAILED DESCRIPTION

[0009] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0010] The first aspect of the present invention provides a phosphorus-free pre-filming agent, the pre-filming agent comprising a reaction product of a compound represented by the following formula I and a compound represented by the following formula II, hydrolyzed polymaleic anhydride and at least one azole compound;

[0011]

[0012] Wherein, R1 is sodium or potassium, R2 is R3, R4 and R5 are independently selected from H or C1-C4 alkyl. R3, R4 and R5 are independently selected from H or C1 alkyl.

[0013] In the present invention, in order to obtain a better pre-filming effect, the weight ratio of the reaction product of the compound represented by Formula I and the compound represented by Formula II to the hydrolyzed polymaleic anhydride is preferably 1:0.4-5.4, which can be 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.4 or the range formed by any two of the above values ​​and the value within the range. The hydrolyzed polymaleic anhydride described in the present invention may exist in the form of a solution when actually used, and the weight ratio of the hydrolyzed polymaleic anhydride in this application is the amount of solute.

[0014] In the present invention, the preparation method of the reaction product may include: reacting the compound shown in Formula I with the compound shown in Formula II under acid catalysis, and directly mixing the compound shown in Formula I with the compound shown in Formula II in water to react. The product after the reaction does not need to remove other components except water, and can be directly used as one of the components of the pre-filming agent of the present application. The weight ratio of the reaction product of the compound shown in Formula I and the compound shown in Formula II in the present application refers to the amount of solid content therein.

[0015] Preferably, the molar ratio of the compound represented by formula I and the compound represented by formula II in the reaction product of the compound represented by formula I and the compound represented by formula II is 1:0.15-6, which can be 1:0.15, 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.5, 1:2, 1:0.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6 or the range formed by any two of the above values ​​and the value within the range. The molar ratio of the compound represented by formula I and the compound represented by formula II can also be controlled to be 1:0.15-6 during the preparation process.

[0016] In the present invention, the acid catalyst is preferably sulfuric acid and / or nitric acid. The molar ratio of the catalyst to the compound represented by formula I is 0.2-6:1, preferably 0.8-4:1, in terms of hydrogen ions.

[0017] Preferably, the reaction conditions include: the mixing is carried out at a temperature sufficient to evaporate water, preferably the mixing is carried out under heating conditions at 100-180° C., and the mixing time is 2-10 hours.

[0018] In the present invention, in order to obtain a better pre-filming effect, the weight ratio of the reaction product of the compound represented by Formula I and the compound represented by Formula II and at least one azole compound is preferably 1:0.02-0.4, and can be 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, 1:0.1, 1:0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.25, 0.3, 0.35, 0.4 or the range formed by any two of the above values ​​and the value within the range.

[0019] In the present invention, in order to obtain a better pre-filming effect, the at least one azole compound is preferably mercaptobenzothiazole and / or benzotriazole.

[0020] The inventors of the present invention have found that when the molecular weight distribution of the reaction product of the compound represented by Formula I and the compound represented by Formula II is in the range of 300-700, the pre-filming effect is the best.

[0021] The inventors of the present invention have found that when the relative molecular weight of the hydrolyzed polymaleic anhydride is 400-800, the pre-filming effect is the best; preferably, the limiting viscosity of the hydrolyzed polymaleic anhydride at 30° C. is 0.06-0.1 dL / g.

[0022] According to a preferred embodiment of the present invention, the pre-filming agent is composed of the above components. Each component can be provided in the form of a solution or a suspension, but the content or dosage thereof is calculated on a dry basis (solid content).

[0023] The second aspect of the present invention provides a pre-filming method, which comprises: contacting an object to be pre-filmed with the pre-filming agent in the presence of water.

[0024] In the present invention, in order to obtain a better pre-filming effect, the concentration of the reaction product of the compound represented by Formula I and the compound represented by Formula II in water is 60-150 mg / L, which can be 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L, 100 mg / L, 110 mg / L, 120 mg / L, 130 mg / L, 140 mg / L, 150 mg / L or the range formed by any two of the above values ​​and the value within the range. Preferably, the concentration of the hydrolyzed polymaleic anhydride is 45 mg / L-120 mg / L , can be 45mg / L, 50mg / L, 60mg / L, 70mg / L, 80mg / L, 90mg / L, 100mg / L, 110mg / L, 120mg / L or the range formed by any two of the above values ​​and the value within the range; more preferably, the concentration of the at least one azole compound shown is 2-5mg / L, can be 2mg / L, 2.5mg / L, 3mg / L, 3.5mg / L, 4mg / L, 4.5mg / L, 5mg / L or the range formed by any two of the above values ​​and the value within the range.

[0025] In the present invention, in order to obtain a better pre-filming effect, the pH of the contact system is controlled to be 6.5-7.5. The contact conditions include: a temperature of 20-45°C, which can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C or any two of the above values ​​and values ​​within the range; a time of 8-72h, which can be 8h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h, 72h or any two of the above values ​​and values ​​within the range; preferably, the pH is controlled by mixing with a pH regulator. More preferably, the acidic regulator is sulfuric acid and / or aminosulfonic acid. Further preferably, the alkaline regulator is sodium bicarbonate and / or sodium carbonate, which can adjust the pH without affecting the pre-filming effect.

[0026] In the present invention, the pre-filming agent is more suitable for treating circulating cooling water with low hardness and low alkalinity. Preferably, the sum of the calcium hardness and the total alkalinity of the water is 150 mg·L -1 Below, it can be 0mg·L -1 、10mg·L -1 , 20mg·L -1 、30mg·L -1 , 40mg·L -1 , 50mg·L -1 、60mg·L -1 、70mg·L -1 、80mg·L -1 、90mg·L -1 、100mg·L -1 、110mg·L -1 、120mg·L -1 、130mg·L -1 、140mg·L -1 、150mg·L -1 Or the range formed by any two of the above values ​​and the value within the range, preferably 20-130 mg·L -1 More specifically, the chloride ion concentration in the water of the contact system is 10-50 mg·L -1 , preferably the pH is 6-8, and more preferably the conductivity is 50-300 μs / cm.

[0027] Preferably, the surface of the object to be pre-coated is metal, such as copper, iron, zinc or aluminum.

[0028] In the present invention, in actual use, the water is generally industrial circulating cooling water. When the industrial circulating cooling water system is newly started or started after maintenance and cleaning, the pre-filming method of the present invention can be used to add the pre-filming agent.

[0029] The invention also provides the use of the above-mentioned non-phosphorus pre-filming agent in prolonging the color development time of copper sulfate titration.

[0030] The present invention will be described in detail below through examples. In the following preparation examples, the molecular weight of the reaction product in the prepared reaction product is tested by mass spectrometry, and the scanning mode is FTMS-p ESI Full ms [100-1000];

[0031] In the following preparation examples, the feed ratio of each monomer actually involved in the polymerization is determined by testing the content of unreacted monomers, and then the content of each structural unit in the polymer is determined. Since there is no monomer residue in the reaction product, the molar ratio of each monomer residue in the reaction product is equal to the molar ratio of the feed amount;

[0032] The hydrolyzed polymaleic anhydride reagent was purchased from Shandong Taihe Science and Technology Co., Ltd., and the solid content determination standard was: GB / T10535-2014.

[0033] The quality of the test water is shown in Table 1.

[0034] Table 1

[0035] Water Quality Calcium hardness Total Alkalinity <![CDATA[Cl - ]]> pH Conductivity Water quality 1 45 25 13 6.5 109 Water quality 2 30 45 18 6.9 133 Water quality 3 50 50 26 6.9 157 Water quality 4 50 80 28 7.1 208 Water quality 5 80 45 31 6.8 231

[0036] Note: pH has no unit, the unit of conductivity is μs / cm, and the other units are mg / L. Calcium hardness and total alkalinity are both measured in CaCO3, the same below. The determination methods of each parameter are as follows: Calcium hardness: refer to standard GB / T 6910-2006; Total alkalinity: refer to standard GB / T15451-2006; Cl - : Refer to standard GB / T 15453-2008; pH value: Refer to standard GB / T 6920-1986; Conductivity: Refer to standard GB / T 6908-2008. The water used in each test is surface water diluted or supplemented with corresponding calcium hardness and alkalinity, where calcium hardness is supplemented with anhydrous CaCl2, calculated as CaCO3; alkalinity is supplemented with anhydrous sodium bicarbonate, calculated as CaCO3.

[0037] The solid content determination method of the product obtained in the preparation example includes:

[0038] Weigh about 1g of the obtained product sample to an accuracy of 0.0002g, place it in a weighed flat weighing dish, and carefully shake it to allow the sample to flow naturally to form a uniform film on the bottom of the dish. Then put it in an electric drying oven, heat it from room temperature, dry it at 120℃ for 4h, and weigh it every 0.5h until constant weight is reached. After constant weight, take it out, put it in a desiccator to cool it to room temperature, and weigh it.

[0039] The solid content calculation formula is: solid content = [(m2-m1) / m] × 100%

[0040] m2: weight of the dried sample and weighing dish, g;

[0041] m1: net weight of weighing dish, g;

[0042] m: The mass of the sample, g.

[0043] Preparation Example 1

[0044] Prepare the reaction product of the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all H): add 32.7g (0.15mol) of the compound represented by formula I (R1 is sodium), 14.9g (0.1mol) of the compound represented by formula II (R3, R4 and R5 are all H) and 100mL of water into a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, start stirring, so that the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all H) are fully dissolved and mixed. Afterwards, 5 g (containing H2SO4, 0.05 mol) of concentrated sulfuric acid was added at 20°C, the oil bath (dimethyl silicone oil) was heated to 130°C, the reaction was carried out for 6 hours, 40 g of water was evaporated, and the remaining liquid was cooled to obtain the reaction product of the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all H), which is the S1 product. No residual monomers (Formula I and Formula II) were found by liquid chromatography, and the solid content was 40% by weight, and the molecular weight distribution was in the range of 327-683.

[0045] Preparation Example 2

[0046] Prepare the reaction product of the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all H): add 32.7g (0.15mol) of the compound represented by formula I (R1 is sodium), 134.1g (0.9mol) of the compound represented by formula II (R3, R4 and R5 are all H) and 100mL of water into a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, start stirring, so that the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all H) are fully dissolved and mixed. Afterwards, 45 g (containing H2SO4, 0.45 mol) of concentrated sulfuric acid was added at 20°C, the oil bath (dimethyl silicone oil) was heated to 130°C, the reaction was carried out for 6 hours, 50 g of water was evaporated, and the remaining liquid was cooled to obtain the reaction product of the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all H), which is the S2 product. No residual monomers (Formula I and Formula II) were found by liquid chromatography, and the solid content was 59.6% by weight and the molecular weight was 327.

[0047] Preparation Example 3

[0048] Prepare the reaction product of the compound represented by formula I (R1 is potassium) and the compound represented by formula II (R3, R4 and R5 are all H): add 23.4g (0.1mol) of the compound represented by formula I (R1 is potassium), 2.3g (0.015mol) of the compound represented by formula II (R3, R4 and R5 are all H) and 100mL of water into a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, start stirring, so that the compound represented by formula I (R1 is potassium) and the compound represented by formula II (R3, R4 and R5 are all H) are fully dissolved and mixed. Afterwards, 3.15 g (containing HNO3, 0.034 mol) of concentrated nitric acid was added at 20°C, the oil bath (dimethyl silicone oil) was heated to 110°C, the reaction was carried out for 2 hours, 25 g of water was evaporated, and the remaining liquid was cooled to obtain the reaction product of the compound represented by formula I (R1 is potassium) and the compound represented by formula II (R3, R4 and R5 are all H), which is the S3 product. No residual monomers (Formula I and Formula II) were found by liquid chromatography, and the solid content was 22.8% by weight, and the molecular weight distribution was in the range of 327-683.

[0049] Preparation Example 4

[0050] Preparation of the reaction product of the compound shown in formula I (R1 is potassium) and the compound shown in formula II (R3, R4 and R5 are all CH3): Add 35.1g (0.15mol) of the compound shown in formula I (R1 is potassium), 19.3g (0.1mol) of the compound shown in formula II (R3, R4 and R5 are all CH3) and 100mL of water to a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, start stirring, and fully dissolve and mix the compound shown in formula I (R1 is potassium) and the compound shown in formula II (R3, R4 and R5 are all CH3). Add 9.3g (containing HNO3, 0.1mol) of concentrated nitric acid at 20°C. The heating bath (heating medium is dimethyl silicone oil) containing the aforementioned flask was heated to 180°C and reacted for 6 hours. 55 g of water was evaporated and the remaining liquid was cooled to obtain the reaction product of the compound represented by formula I (R1 is potassium) and the compound represented by formula II (R3, R4 and R5 are all CH3), which is the S4 product. No residual monomers (Formula I and Formula II) were found by liquid chromatography, and the solid content was 44.2% by weight. The molecular weight distribution was in the range of 365-700.

[0051] Preparation Example 5

[0052] Preparation of the reaction product of the compound of formula I (R1 is sodium) and the compound of formula II (R3, R4 and R5 are all CH3): Add 32.7g (0.15mol) of the compound of formula I (R1 is sodium), 19.3g (0.1mol) of the compound of formula II (R3, R4 and R5 are all CH3) and 100mL of water to a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, start stirring to fully dissolve and mix the compound of formula I (R1 is sodium) and the compound of formula II (R3, R4 and R5 are all CH3). Add 9.3g (containing 0.1mol of HNO3) of concentrated nitric acid at 20°C. The heating bath (heating medium is dimethyl silicone oil) containing the aforementioned flask was heated to 180°C, reacted for 6 hours, 50 g of water was evaporated, and the remaining liquid was cooled to obtain the reaction product of the compound represented by formula I (R1 is sodium) and the compound represented by formula II (R3, R4 and R5 are all CH3), which is the S5 product. No residual monomers (Formula I and Formula II) were found by liquid chromatography, and the solid content was 44.5% by weight. The molecular weight distribution was in the range of 365-700.

[0053] Preparation Example 6

[0054] Prepare the reaction product of potassium citrate and the compound shown in formula II (R3, R4 and R5 are all H): add 46.0g (0.15mol) of potassium citrate, 14.9g (0.1mol) of the compound shown in formula II (R3, R4 and R5 are all H) and 100mL of water into a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, start stirring, so that the potassium citrate and the compound shown in formula II (R3, R4 and R5 are all H) are fully dissolved and mixed. Afterwards, 5 g (containing H2SO4, 0.05 mol) of concentrated sulfuric acid was added at 20°C, the oil bath (dimethyl silicone oil) was heated to 130°C, the reaction was carried out for 6 hours, 40 g of water was evaporated, and the remaining liquid was cooled to obtain the reaction product of sodium citrate and the compound represented by formula II (R3, R4 and R5 are all H), which is the S6 product. No residual monomers (potassium citrate and formula II) were found by liquid chromatography, and the solid content was 42% by weight, and the molecular weight distribution was in the range of 343-692.

[0055] Preparation Example 7

[0056] Preparation of the reaction product of the compound shown in formula I (R1 is sodium) and ethanolamine: 32.7g (0.15mol) of the compound shown in formula I (R1 is sodium), 6.1g (0.1mol) of ethanolamine and 100mL of water were added to a four-necked flask equipped with a stirrer, a distillation apparatus and a thermometer, and stirring was started to fully dissolve and mix the compound shown in formula I (R1 is sodium) and ethanolamine. After that, 5g (containing H2SO4, 0.05mol) of concentrated sulfuric acid was added at 20°C, the oil bath (dimethyl silicone oil) was heated to 130°C, the reaction was carried out for 6h, 40g of water was evaporated, and the remaining liquid was cooled to obtain the reaction product of the compound shown in formula I (R1 is sodium) and ethanolamine, which is S7 product. No residual monomer (formula I and ethanolamine) was found by liquid chromatography, and its solid content was 37% by weight, and its molecular weight distribution was in the range of 338-663.

[0057] Example 1

[0058] Weigh 46.7 g of S1 product with a solid content of 40 wt % (prepared according to Preparation Example 1), 16.7 g of hydrolyzed polymaleic anhydride reagent (limiting viscosity at 30° C. is 0.08 dl / g, weight-average molecular weight is 695 g / mol, and hydrolyzed polymaleic anhydride content is 55 wt %), and 1.3 g of benzotriazole, add 35.3 g of water, and shake well to obtain the required 100 g of the preparation.

[0059] The agent was added to the test water to make the concentration of the agent 300 mg / L, and added to a 2L beaker to obtain a cleaning pre-filming agent, and a rotating hanging film pre-filming test was carried out. The test temperature was 25°C, the test time was 24h, the test water was water quality 1 in Table 1, the pH was controlled at 7.2±0.2, the pH regulator was sodium bicarbonate, and the pre-filming test of the phosphorus-free pre-filming agent was carried out in accordance with the national standard HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems", wherein the hanging film material was carbon steel, and the carbon steel model was 20#. Three new hanging films were processed according to the requirements of HG / T3523-2008, hung on the hanging film rack of the rotating hanging film instrument, and then placed in a 2L beaker containing the cleaning pre-filming agent, and the rotation rate was 75r / min. The test results of film color and state are shown in Table 2.

[0060] Example 2

[0061] Weigh 23.3 g of S2 product with a solid content of 59.6 wt % (prepared according to Preparation Example 2), 33.3 g of hydrolyzed polymaleic anhydride reagent (limiting viscosity at 30°C is 0.075 dl / g, weight-average molecular weight is 631 g / mol, and hydrolyzed polymaleic anhydride content is 55 wt %), and 1 g of benzotriazole, add 42.0 g of water, and shake well to obtain the required 100 g of the agent.

[0062] The agent was added to the test water to make the concentration of the agent 300 mg / L, and then added to a 2L beaker to obtain a cleaning pre-filming agent. The rotating hanging film pre-filming test was carried out at a test temperature of 25°C and a test time of 24h. The test water was water quality 2 in Table 1, and the pH was controlled at 6.8±0.2. The pH regulator was sodium bicarbonate. The pre-filming test of the phosphorus-free pre-filming agent was carried out in accordance with the national standard HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems". The hanging film material was carbon steel, and the carbon steel model was 20#. Three new hanging films were processed according to the requirements of HG / T3523-2008, hung on the hanging film rack of the rotating hanging film instrument, and then placed in a 2L beaker containing the cleaning pre-filming agent, and the rotation rate was 75r / min. The test results of film color and state are shown in Table 2.

[0063] Example 3

[0064] Weigh 30.0 g of S3 product with a solid content of 22.8 wt % (prepared according to Preparation Example 3), 38.3 g of hydrolyzed polymaleic anhydride reagent (limiting viscosity at 30°C is 0.065 dl / g, weight-average molecular weight is 563 g / mol, and hydrolyzed polymaleic anhydride content is 55 wt %), and 0.7 g of benzotriazole, add 31.0 g of water, and shake well to obtain the required 100 g of the preparation.

[0065] The agent was added to the test water to make the concentration of the agent 300 mg / L, and then added to a 2L beaker to obtain a cleaning pre-filming agent. The rotating hanging film pre-filming test was carried out. The test temperature was 25°C, the test time was 24h, the test water was water quality 3 in Table 1, the pH was controlled at 7.0±0.2, and the pH regulator was aminosulfonic acid. The pre-filming test of the phosphorus-free pre-filming agent was carried out in accordance with the national standard HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems". Among them, the hanging film material was carbon steel, and the carbon steel model was 20#. Three new hanging films were processed according to the requirements of HG / T3523-2008, hung on the hanging film rack of the rotating hanging film instrument, and then placed in a 2L beaker containing the cleaning pre-filming agent, and the rotation rate was 75r / min. The test results of film color and state are shown in Table 2.

[0066] Example 4

[0067] Weigh 20.0 g of S4 product with a solid content of 44.2 wt % (prepared according to Preparation Example 4), 26.7 g of hydrolyzed polymaleic anhydride reagent (limiting viscosity at 30° C. is 0.085 dl / g, weight-average molecular weight is 725 g / mol, and hydrolyzed polymaleic anhydride content is 55 wt %), and 0.7 g of benzotriazole, add 51.7 g of water, and shake well to obtain 100 g of the required preparation.

[0068] The agent was added to the test water to make the concentration of the agent 300 mg / L, and then added to a 2L beaker to obtain a cleaning pre-filming agent. The rotating hanging film pre-filming test was carried out. The test temperature was 25°C, the test time was 24h, the test water was water quality 4 in Table 1, the pH was controlled at 6.7±0.2, and the pH regulator was aminosulfonic acid. The pre-filming test of the phosphorus-free pre-filming agent was carried out in accordance with the national standard HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems". Among them, the hanging film material was carbon steel, and the carbon steel model was 20#. Three new hanging films were processed according to the requirements of HG / T3523-2008, hung on the hanging film rack of the rotating hanging film instrument, and then placed in a 2L beaker containing the cleaning pre-filming agent, and the rotation rate was 75r / min. The test results of film color and state are shown in Table 2.

[0069] Example 5

[0070] Weigh 40 g of S5 product with a solid content of 44.5 wt % (prepared according to Preparation Example 5), 30.0 g of hydrolyzed polymaleic anhydride reagent (limiting viscosity at 30° C. is 0.095 dl / g, weight-average molecular weight is 772 g / mol, and hydrolyzed polymaleic anhydride content is 55 wt %), and 1.0 g of benzotriazole, add 29.0 g of water, and shake well to obtain 100 g of the desired preparation.

[0071] The agent was added to the test water to make the concentration of the agent 300 mg / L, and added to a 2L beaker to obtain a cleaning pre-filming agent, and a rotating hanging film pre-filming test was carried out. The test temperature was 25°C, the test time was 24h, the test water was water quality 5 in Table 1, the pH was controlled at 7.3±0.2, the pH regulator was aminosulfonic acid, and the pre-filming test of the phosphorus-free pre-filming agent was carried out in accordance with the national standard HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems", wherein the hanging film material was carbon steel, and the carbon steel model was 20#. Three new hanging films were processed according to the requirements of HG / T3523-2008, hung on the hanging film rack of the rotating hanging film instrument, and then placed in a 2L beaker containing the cleaning pre-filming agent, and the rotation rate was 75r / min. The test results of film color and state are shown in Table 2.

[0072] Example 6

[0073] The method of Example 1 was followed, except that the amount of hydrolyzed polymaleic anhydride was 8.4 g and the amount of water was 43.6 g. The test results are shown in Table 2.

[0074] Example 7

[0075] The method of Example 1 was followed, except that the amount of benzotriazole was 9.3 g and the amount of water was 27.3 g. The test results are shown in Table 2.

[0076] Comparative Example 1

[0077] The method of Example 1 was followed, except that the S1 product was not added, the hydrolyzed polymaleic anhydride was 60 g, the benzotriazole was 4.7 g, and the water was 35.3 g. The test results are shown in Table 2.

[0078] Comparative Example 2

[0079] The method of Example 1 was followed, except that no hydrolyzed polymaleic anhydride was added, the S1 product was 70 g, the benzotriazole was 1.9 g, and the water was 28.1 g. The test results are shown in Table 2.

[0080] Comparative Example 3

[0081] The method of Example 1 was followed, except that no benzotriazole was added, the S1 product was 50.2 g, the hydrolyzed polymaleic anhydride was 17.9 g, and the water was 31.9 g. The test results are shown in Table 2.

[0082] Comparative Example 4

[0083] The method of Example 1 was followed, except that the hydrolyzed polymaleic anhydride was replaced with a maleic acid-acrylic acid copolymer (weight average molecular weight 616 g / mol, Shandong Taihe Technology Co., Ltd.). The test results are shown in Table 2.

[0084] Comparative Example 5

[0085] The method of Example 1 was followed, except that benzotriazole was replaced with hexamethylenetetramine. The test results are shown in Table 2.

[0086] Comparative Example 6

[0087] The method of Example 1 was followed, except that the S1 product was replaced with the S6 product in Preparation Example 6. The test results are shown in Table 2.

[0088] Comparative Example 7

[0089] The method of Example 1 is followed, except that the S1 product is replaced by the S7 product in Preparation Example 7.

[0090] Test Case

[0091] (1) After the pre-filming is completed, take out the test pieces and blow dry one of them with a hair dryer. According to the requirements of HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems", the time difference of the color change of the membrane in response to the drop of copper sulfate solution should be ≥10 seconds, and the color development time of saturated copper sulfate is shown in Table 2.

[0092] (2) After the other two test pieces were taken out, the weights of the test pieces before and after pre-coating were recorded, and the average corrosion rate was calculated. The corrosion rate is shown in Table 2.

[0093] The average corrosion rate is calculated as:

[0094] F=(C×△W) / (A×T×ρ)

[0095] C: calculation constant, in mm / a, C = 8.76 × 10 7 ;

[0096] △W: Corrosion weight loss of specimen (g);

[0097] A: Area of ​​the specimen (cm 2 );

[0098] T: corrosion test time (h);

[0099] ρ: Density of the specimen material (kg / m 3 ).

[0100] Table 2

[0101] serial number Saturated copper sulfate color development time / s Film color and state Corrosion rate / (mm / a) Example 1 43.0 Continuous uniform blue-purple film 0.015 Example 2 40.8 Continuous and uniform blue film 0.018 Example 3 28.3 Blue film 0.030 Example 4 35.8 Blue-purple membrane 0.023 Example 5 45.3 Continuous uniform blue-purple film 0.015 Example 6 8.8 No obvious film 0.069 Example 7 5.6 Discontinuous light blue film 0.056 Comparative Example 1 4.5 No obvious film 0.102 Comparative Example 2 3.7 No obvious film 0.079 Comparative Example 3 7.9 No obvious film 0.065 Comparative Example 4 5.3 No obvious film 0.047 Comparative Example 5 3.9 No obvious film 0.081 Comparative Example 6 6.6 No obvious film 0.055 Comparative Example 7 8.7 No obvious film 0.106

[0102] It can be seen from the results that, using the embodiments of the present invention, the color change time difference of the film formed by the pre-filming agent to the dripping of copper sulfate solution is greater than the requirement of HG / T3778-2005 "Technical Rules for Chemical Cleaning and Pre-filming Treatment of Cooling Water Systems", which is not less than 10 seconds. The effect is obviously better than the requirements of HG / 3778-2005, the corrosion rate is low, and the pre-filming effect is better.

[0103] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A phosphorus-free pre-filming agent, characterized in that: The phosphorus-free pre-filming agent comprises: a reaction product of a compound represented by Formula I and a compound represented by Formula II, hydrolyzed polymaleic anhydride and at least one azole compound; Wherein, R1 is sodium or potassium, R2 is R3, R4 and R5 are each independently selected from H or C1-C4 alkyl.

2. The phosphorus-free pre-filming agent according to claim 1, wherein The weight ratio of the reaction product of the compound represented by formula I and the compound represented by formula II, the hydrolyzed polymaleic anhydride and at least one azole compound is 1:0.4-5.4:0.02-0.

2.

3. The phosphorus-free pre-filming agent according to claim 1 or 2, wherein: The molar ratio of the residue of the compound represented by formula I to the residue of the compound represented by formula II in the reaction product of the compound represented by formula I and the compound represented by formula II is 1:0.15-6; And / or, the at least one azole compound is mercaptobenzothiazole and / or benzotriazole.

4. The phosphorus-free pre-filming agent according to claim 1 or 2, wherein: The molecular weight distribution of the reaction product of the compound represented by formula I and the compound represented by formula II is in the range of 300-700.

5. The phosphorus-free pre-filming agent according to claim 1 or 2, wherein: The weight average molecular weight of the hydrolyzed polymaleic anhydride is 400-800 g / mol; And / or, the hydrolyzed polymaleic anhydride has a limiting viscosity of 0.06-0.1 dL / g at 30°C.

6. A pre-filming method, characterized in that: The method comprises: contacting the object to be pre-filmed with the phosphorus-free pre-filming agent according to any one of claims 1 to 5 in the presence of water.

7. The method according to claim 6, wherein: Controlling the pH of the contact system to be 6.5-7.5; And / or, the contacting conditions include: temperature of 20-45°C, time of 8-72h; And / or, the concentration of the reaction product of the compound represented by Formula I and the compound represented by Formula II in water is 60-150 mg / L.

8. The method according to claim 6 or 7, wherein: The sum of calcium hardness and total alkalinity of the water is 150 mg·L -1 the following; And / or, the surface of the object to be pre-coated is metal.

9. The method according to claim 7, wherein: The pH of the contact system is controlled by mixing with a pH regulator, wherein the pH regulator is an acidic regulator or an alkaline regulator.

10. The method according to claim 9, wherein: The acidic regulator is sulfuric acid and / or aminosulfonic acid; And / or, the alkaline regulator is sodium bicarbonate and / or sodium carbonate.

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