Abstract: Zinc 2-mercaptobenzothiazole (ZMBT) is widely used in the matting system of powder coatings. In this paper, the following hypothesis was put forward for the structural model of its matting: the structural model of “epoxy resin curing agent + zinc ion” can be used as a matting agent for epoxy resin powder coatings. Based on this assumption, two aromatic amines, 4,4-diaminobenzene methane (DDM) and 4,4-diaminodiphenylsulfone (DDS), were synthesized as complexes with zinc chloride, and the matting effects of the two aromatic amines and the corresponding zinc salts were compared with those of ZMBT. The results showed that both complexes had similar matting effects to ZMBT in powder coatings, but lower film gloss could not be obtained by compounding with other matting substances.

1 Introduction
Zinc 2-mercaptobenzothiazole (ZMBT) as the basis of the establishment of the powder coating matting system is widely used; the system matting effect is stable, the gloss can be adjustable, and at the same time, has excellent anti-yellowing performance, but the storage stability of powder coatings is not good. ZMBT is made of 2-mercaptobenzothiazole (MBT) in alkaline conditions and zinc ions complexed from the decomposition of the [1], in which MBT can be and epoxy group [1], the ring-opening addition reaction [1]. ring-opening addition reaction [2], which can be used as a curing agent or curing accelerator for epoxy resins. In order to investigate the matting mechanism of aromatic amine zinc salts on powder coatings, we put forward the following hypothesis: is it possible to achieve the matting effect when the curing agent of epoxy resin is combined with zinc ions?
Based on the above hypothesis, we selected two aromatic amine epoxy resin curing agents: 4,4-diaminobenzylmethane (DDM) and 4,4-diaminodiphenylsulfone (DDS), of which DDM is more reactive and can directly cure E-12 epoxy resin for powder coatings, while DDS is less reactive and can be reacted with liquid epoxy, and both of the aromatic amines can be effectively complexed with zinc ions [3]. Therefore, in this paper, we designed and synthesized the complexes of the above two epoxy resin curing agents with zinc ions (as shown in Fig. 1), and compared the matting effects of the two aromatic amine curing agents and the corresponding zinc salt complexes with the conventional zinc 2-mercaptobenzothiazole system.

2 Experimental Part
2.1 Raw materials
Zinc chloride (analytically pure), ethanol (95%), DDM, DDS, ZMBT, zinc dimethyldithiocarbamate (ZDEC, melting point 250°C), epoxy resin E-12, Xinzhongfa 50/50 polyester P5086, Anhui Excalibur 50/50 polyester SJ3#B, Yulin polyester YL5050, aluminum salts, barium matting, lightening agent, leveling agent, benzoin, carbon black etc. are all industrial grade.
2.2 Experimental equipment
Three-necked flask (500mL), oil bath with magnetic stirring, filter extraction device, twin-screw extruder, high-pressure electrostatic spraying equipment, constant temperature blast oven, coating film thickness meter, gloss meter, coating film impactor, metallurgical microscope and so on.
2.3 DDM/zinc ion complex preparation
The synthesis process of aromatic amine/zinc salt complex was as follows [4], 19.8 g DDM was added to the flask with 100 mL of ethanol and stirred in an oil bath at 60°C until complete dissolution, 14 g of zinc chloride was added to the solution, a large number of solids were precipitated immediately, and the reaction was continued to be stirred for 30 min, then cooled, filtered, washed, and dried in oven at 50°C for 2 h to obtain 30 g of yellowish powdered solids, i.e., DDM/ Zn2+ complex, yield 88.7%, melting point 320 ℃.
2.4 Preparation of DDS/Zn ion complexes
Add 24.8 g of DDS and 100 mL of ethanol in a flask, stir in an oil bath at 60 ℃ until completely dissolved, add 14 g of zinc chloride to the solution, stir the reaction for 2 h, then cool, filter, wash, and dry in an oven at 50 ℃ for 2 h to obtain 32 g of white powdery solid, i.e., DDS/Zn2+ complex, with a yield of 82.3% and a melting point of 315 ℃.
2.5 Powder coating and coating preparation
The experimental resin, curing agent and filler were mixed well according to the formula, and then incorporated into the extrusion → cooling and pressing → crushing → sieving → powder coating, and then electrostatically sprayed on the tinplate, with the thickness of 70~90 μm, and then cured at 200 ℃/12 min to obtain the coating film.

02 Improvement of mechanical properties additives
This type of additives is to enhance the waterborne polyurethane material some specific physical properties of the substance. Waterborne polyurethane material itself is not any performance is so significant, the only additives will have the value of use.
03Processing performance improvement additives
Waterborne polyurethane materials have many characteristics of the material itself, such as viscosity, which makes processing more complicated, therefore, in the processing and use of waterborne polyurethane, it is more and more critical to improve the processing performance of the additives.
04Auxiliaries to improve surface properties and appearance
Waterborne polyurethane has antistatic agents with antistatic effects, whitening agents for coatings, and sliding agents.
05Flame retardant additives
Auxiliaries that make materials incombustible or prevent materials from burning.
06Auxiliaries to improve flow and rheological properties
Waterborne polyurethane materials have different requirements according to the differences in the applicable objects. Such as wood adhesive due to the porous nature of the material, the viscosity of the water-based polyurethane adhesive is required to be large enough to avoid the glue to penetrate into the internal structure of the wood and it is difficult to ensure the amount of sizing, at this time, it is necessary to add thickening agent.

Polyurethane adhesive manufacturing in addition to isocyanate and polyol basic raw materials, add a variety of additives is also very important. Additives can be selected production process, improve the adhesive sizing process, improve product quality and expand the scope of application.
Solvent
In order to adjust the viscosity of polyurethane adhesive, easy to process operation, in the preparation process of polyurethane adhesive or formulated for use, often use solvents. Organic solvents for polyurethane adhesives must be “urethane grade solvents”, which basically do not contain water, alcohols and other active hydrogen compounds. “Urethane grade solvent” is the isocyanate equivalent as the main indicator, that is, the consumption of 1 mol of NCO-based solvent required for the number of grams, the value must be greater than 2,500, less than 2,500 below is unqualified. Therefore, the purity of solvents used in polyurethane adhesives is higher than that of general industrial products.

Polyurethane adhesive solvents usually include ketones (milk methyl ethyl ketone, acetone), aromatic hydrocarbons (such as toluene〉, dimethyl formamide, tetrahydrofurfura, etc.. The choice of solvent can be based on the principle of solubilization of polyurethane molecules and solvents – that is, similar solubility parameters SP, similar polarity, and the solvent itself, such as the rate of volatilization and other factors to determine. Can use mixed solvents to improve solubility, adjust the volatilization rate to adapt to the requirements of different bonding processes.
Physical properties of solvents commonly used in polyurethane adhesives
Catalyst
The preparation of polyurethane resin there are mainly three kinds of reaction need catalyst: NCO/NCO, NCO/OH, NCO/H2O. the manufacture of polyurethane adhesive mainly need to use NCO/OH reaction catalyst and NCO/H2O reaction catalyst.

As defoamer
Dimethylsiloxane Mixed Cyclic (DMC) is widely used as an antifoam agent because of its low surface tension, good chemical stability, non-toxicity and other characteristics. It is used in petroleum, chemical, medical, pharmaceutical, food processing, textile, printing and dyeing, paper making and other industries, only need to add a small amount to achieve good defoaming effect.
As mold release agent
Dimethylsiloxane Mixed Cyclic (DMC) is often used as a mold release agent for molding and precision casting of various rubber and plastic products due to its non-adhesion to rubber, plastic, metal and other materials. This not only makes mold release easy, but also ensures that the surface of the product is smooth and clear.
As an insulating, dust-proof, and mold-proof coating
A layer of Dimethicone Mixed Cyclic (DMC) is dip-coated on the surface of glass and ceramics, and after heat treatment, it can form a semi-permanent waterproof, mold-proof and insulating film. In addition, it can be used to treat insulating devices to improve their insulating properties or optical instruments to prevent mold from developing on parts such as lenses.
As a lubricant

Dimethylsiloxane Cyclic Mixture (DMC) is suitable as a lubricant for rubber and plastic shaft conveyor bearings and gears. It can also be used as a lubricant for rolling friction between steel at high temperatures, or for friction between steel and other metals.
As an additive
Dimethylsiloxane Cyclic Mixture (DMC) can be used as a brightener for paints, adding gloss and water repellency to paints. It also improves the printing quality of inks and the brightness of varnishes2.
In summary, dimethicone mixed cyclic (DMC), as a multifunctional silicone intermediate, has a wide range of applications in several industries. From the production of silicone rubber and silicone fluids to its use as defoamers, mold release agents, insulating coatings, lubricants and additives, its uses are diverse and important.

In this study, we propose a simple and easy method to prepare superhydrophobic coatings that can be applied on a large scale: firstly, by utilizing the internal porous structure of MCM-41, its extremely large specific surface area (>900 m2/g) and strong adsorptive properties, low surface energy PDMS was loaded into MCM-41 using a vacuum-negative pressure method, resulting in the production of hydrophobically modified MCM-41 (MCM-41/PDMS); Subsequently, MCM-41/PDMS, epoxy resin, curing agent and diluent were blended using the blending method to produce the superhydrophobic coatings, and the coatings were sprayed on the surface of the substrate using the simple spraying method to form the epoxy/polydimethylsiloxane/MCM-41 superhydrophobic coatings. In addition, by adjusting the ratio of MCM-41/PDMS and epoxy resin, a balance of hydrophobicity and adhesion was obtained, and mechanical durability tests such as tape peel resistance test and abrasion resistance test were performed on the superhydrophobic coatings under this formulation.

Translated with DeepL.com (free version)

Arabinose, also known as L(+)-Ganaldose, L(+)-Apentose, pectinose, etc. It is originally a L-monosaccharide extracted from the colloid secreted by the Arabic tree through complex chemical and physical methods. Natural L-arabinose rarely exists free. D-arabinose-5-phosphate disodium salt is an arabinose derivative and can be used as a pharmaceutical synthesis intermediate. If D-arabinose-5-phosphate disodium salt is inhaled, move the patient to fresh air; if skin contact occurs, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical attention if you feel unwell.

Preparation^[1]

D-arabinose-5-phosphate disodium salt can be used as a pharmaceutical synthesis intermediate, such as preparing arabinose-5-[(2-hydroxy-3-N, N, N-trimethylammonium) propane [base] phosphate: 2.7g (0.01mol) D-arabinose-5-phosphate disodium salt (manufactured by Sigma Co.), 50g water and 10g 1NHCl were introduced into the reactor and heated to 60°C. Then, 3.0g (0.02mol) glycidyltrimethylammonium chloride solution dissolved in 10g of ion-exchange water was added dropwise within 2 hours while maintaining the reaction system at 60°C. Next, the reaction was carried out at 60°C for 3 hours. After the reaction is completed, the solvent is distilled off under reduced pressure, and the residue is washed with ethanol 10 times the volume of the remaining plastic deodorant residue to remove unreacted glycidyltrimethylammonium chloride. The obtained crude product was purified by ion gas phase silica exchange chromatography (ion exchange resin: AG501X8, trade name, manufactured by BIO-RAD Co.). Thus, 1.1 g of arabinose-5-[(2-hydroxy-3-N,N,N-trimethylamino)propyl]phosphate was obtained (isolated yield: 32%).

As a new type of phosphorus-based flame retardant, aluminum diethylphosphinate has high thermal stability, chemical stability and environmental friendliness. It can be used as an excellent flame retardant for polymer materials to replace environmentally harmful halogens. Flame retardants. Organic aluminum hypophosphite and zinc salts have good flame retardancy due to their high phosphorus content. At the same time, due to the introduction of alkyl groups in the molecular structure, their hydrophobicity and thermal decomposition temperature are greatly increased compared to inorganic hypophosphite. Applications In polymer materials, it will not migrate or absorb moisture, can withstand high processing temperatures, and will not cause a decrease in the insulation performance of the material. It has good compatibility with the matrix resin and can maintain the mechanical properties of the matrix material. Due to these characteristics as an excellent flame retardant, it has been widely used in flame retardant fields of engineering plastics such as high processing temperatures, high shear strength, and high CTI values, especially in fields such as glass fiber reinforced nylon and polyester.

Preparation^[1]

1. Take 100 grams of sodium hypophosphite monohydrate and first dissolve it in 556g of water. Then, the mixed solution and stirring rod were added to a 2L self-designed reactor equipped with a thermometer and a line bubble aerator.

2. When the solution is heated to 30°C in the hot water bath, ethylene enters the reactor in the form of microbubbles through the linear bubble aerator. At the same time, a mixed solution of 8 mL benzophenone, 2 mL reactive amine, 9 mL persulfate and 21 mL threonine was added dropwise to the linear bubble aerator, and blown into the reactor through the flow of ethylene, that is, ethylene and photoinitiator were added simultaneously. Add to heated, stirred hypophosphite solution. The reactor was exposed to UV light generated by an appropriate light source (500W high pressure, quartz, mercury vapor lamp). After the addition was complete, the reaction mixture was stirred vigorously and held at 30°C for 2.8 hours.

3. Evaporate the final solution obtained in step 2 in a vacuum to remove the solvent, and dilute it with 650 mL of distilled water to obtain sodium diethylphosphinate.

4. Add distilled water, raise the temperature to 88°C, and drop in 30% Al₂(SO₄)₃18H ₂O aqueous solution, the dropping rate is controlled between 2.5L and 10L/min, and the dropping time is 30-60min. After the dropwise addition, the reaction is completed for 3 hours to obtain a white precipitate, cool it, and filter the precipitate to form a filter cake. After washing with distilled water, heat and dry under vacuum to obtain a white powdery solid, that is, diethyl aluminum diethyl hypophosphite;

5. The yield of the finally obtained aluminum diethylphosphinate was 120.7g, with a yield of 98.9%, and the purity measured by HPLC was 99.3%.

Flame retardant mechanism^[2]

The main chemical bonds in the structure of diethyl aluminum phosphinate are P-C, P=O, and P-O. Its flame retardant process is relatively complicated. Since aluminum diethyl phosphinate itself has a high phosphorus content, it has The basic flame retardant characteristics of phosphorus flame retardants are that they are both gas phase flame retardant and condensed phase flame retardant. First, aluminum diethyl hypophosphite is thermally decomposed at high temperatures. The (PO*) free radicals formed from P-O can capture the more active O and OH free radicals in the air, which can reduce the oxygen content in the limited space to a certain extent. content to terminate the combustion chain reaction. On the other hand, aluminum diethyl hypophosphite forms a condensed phase non-flammable liquid membrane during the reaction between high temperature and oxygen, covering the surface of the burning material to isolate the air and achieve a flame retardant effect. The phosphoric acid absorbs the gas during the heating process. It is thermally decomposed into metaphosphoric acid, and metaphosphoric acid is further decomposed to form P, P* and water, which effectively absorbs the OH and NH₂^– produced in the matrix, and at the same time makes the It absorbs heat and dehydrates and carbonizes the matrix. The final P element of the most organic silicone coating additives forms a stable carbon layer of pearlescent pigments to fix the carbon skeleton of some combustibles on the surface of the substrate to form a heat insulation layer. This carbon layer isolates oxygen and is difficult to burn. Diethyl hypophosphorous acid Salt can achieve good flame retardant effect.

Apply^[2]

As early as the late 1970s and early 1980s, the American Pennwalt Company had been testing the properties of various dialkyl hyponates. The American company Ticona has studied the performance of zinc, aluminum and calcium phosphinate as flame retardants in PA and PBT, and concluded that the addition amount of aluminum/calcium methylethylphosphinate in PBT is 15% and in PA The amount of addition inAt 20%, vertical combustion UL94 can reach V-0 level. The application of aluminum diethyl hypophosphite in polyester is relatively mature and relatively successful. Ramani et al. added a compound flame retardant of aluminum diethyl hypophosphite (ADP) and montmorillonite in a certain proportion to butylene terephthalate resin, which can effectively improve its flame retardant properties. When montmorillonite The soil content is 2.5%, the ADP content is 15.5%, the limiting oxygen index (LOI value) of the composite resin is as high as 35.5%, and the vertical combustion test shows that its fire rating can reach UL-94/V-O. In the process of preparing flame-retardant polyester (PET), Brehme et al. used 20% aluminum diethyl hypophosphite to increase the LOI value of their terephthalic acid composite resin to 45.5%, while also reaching the UL94/V0 standard. . Braun U et al. studied the synergistic flame retardant mechanism of nylon 66 using a phosphorus-nitrogen composite flame retardant. The phosphorus-nitrogen system mainly consists of aluminum diethylphosphinate and melamine polyphosphate. Research on its flame retardant mechanism using equipment such as thermogravimetry and scanning electron microscopy shows that the synergistic flame retardant has good flame retardant effects.

Ethylene phosphorus (chloroethylphosphonic acid) is a plant growth regulator that slowly releases ethylene when the pH value is greater than 3, and the residue is non-toxic and harmless phosphate. Ethylene is an excellent plant growth regulator. It plays an important role in growth processes such as seed germination, plant growth, flowering, fruit ripening, tissue senescence and shedding. In addition, when plants are exposed to harsh environmental stress, attack by pests and diseases, or mechanical damage, ethylene can respond quickly and enhance various plant resistances.

However, since ethylene is often a gaseous substance and cannot be used directly in the field or outdoors, the application of ethylene on plants is greatly limited. The synthesis of vinyl phosphorus provides the possibility for the application of ethylene on plants. The pH value of plant tissue cell fluid is generally greater than 4. Ethylene phosphorus sprayed on the plant surface enters the functional plant tissue through plant seeds, leaves or fruits, and then the ethylene released has the same effect as the endogenous ethylene hormone. Ethylene phosphorus’ ripening technology for bananas and other agricultural products has been used around the world for more than 100 years, and has been used in my country for nearly 50 years.

Vinyl phosphorus has been gradually popularized in my country for applications in rubber flow, fruit ripening, tobacco leaf yellowing, and grain production due to its ability to increase plant milk secretion, accelerate maturation, abscission, senescence, promote flowering, and control growth. Greening and increasing production of crops and melons, and increasing the sugar content of sugarcane. At present, there are more than 50 kinds of food and cash crops that use ethephon all year round around the world, and it has broad application prospects in agriculture and horticulture.

Physical and chemical properties^[1]

Vinyl phosphorus is a plant growth regulator that promotes maturation and is widely used in cotton, rubber, bananas, tomatoes, tobacco leaves, rice and other plants. The chemical name of vinyl phosphorus is 2-chloroethylphosphonic acid. It has good water solubility and is used on crops, usually using aqueous agents. Currently, 40% vinyl phosphorus aqueous agents are widely used. In order to reduce the cost of packaging and transportation and improve the use effect, manufacturers try to increase the concentration of vinyl phosphorus aqueous agent. At present, the conventional vinyl phosphorus technical material is solid vinyl phosphorus with a content of 80%-90%.

The concentration range of the ethephon aqueous agent prepared from the above-mentioned raw materials is generally 65%-70%. If the concentration is above 70%, solid ethylene phosphorus will precipitate during the 0°C cold storage test, affecting storage and use. . It has been reported that 80%-90% ethylene phosphorus original drug is used, ammonia gas is introduced during the preparation process, or ammonium bicarbonate is added to change the freezing point of the ethylene phosphorus solution diethanolamine, and 70%-80% diethanolamine can be prepared. Liquid vinyl phosphorus. However, the above method adds ammonia or ammonium bicarbonate, which increases the cost of raw materials in the production process. The total production cost of the enterprise cannot be saved, and there is no advantage in market competition.

Preparation ^[2]

The synthesis of vinyl phosphorus was first reported by Kabachnik MI and Rossiiskaya PA in 1946, and was subsequently reported in many literatures. According to its reaction mechanism, it can be divided into two main types. One is through Michaelis-Arbuzon rearrangement reaction, which mainly includes the synthesis method using ethylene oxide as raw material and phosphoric acid or alkyl phosphonate as raw material; the other is through free radical reaction. The reaction can be a synthesis method of reacting phosphite diester with vinyl chloride or vinyl acetate.

my country’s industry currently uses the phosphorus trichloride-ethylene oxide method to produce ethylene phosphorus. The reactions in each step are as follows:

(l) Esterification reaction of phosphorus trichloride and ethylene oxide

(2) Rearrangement reaction of tris(2-chloroethyl)phosphite

Acidolysis of (3) 2-chloroethylphosphonate di(2-chloroethyl) ester

This method has the advantages of lower raw material cost and simpler process operation using the original dispersant imported from Germany, but it also has the disadvantages of low selectivity of each reaction step and more impurities. The main by-product in the esterification reaction is chloroethanol, which is produced due to the reaction between hydrogen chloride in phosphorus trichloride and ethylene oxide; the main by-product in the rearrangement reaction is chloroethanol, which is generated by dehydration of chloroethanol at high temperature. The dichloroethane and phosphonous acid, 2-chloroethylphosphonic acid diester produced by the reaction of ethyl chloride, chloroethanol and phosphorus trichloride remove one molecule of dichloroethane or one molecule of hydrogen chloride in the molecule, or the cyclic ester or Vinyl phosphonic acid diester; the main by-products in the acidolysis reaction are vinyl phosphoric acid produced by the reaction of vinyl phosphoric acid diester and hydrogen chloride, and hydroxyethyl produced by the reaction of 2-chloroethylphosphonic acid and a small amount of water in hydrogen chloride. During the acidolysis process of phosphonic acid and high temperature for a long time, part of the ethylene phosphorus undergoes intermolecular and intramolecular dehydration to form ethylene phosphoric anhydride; during the production process, the fluctuating process conditions corrode the equipment, causing the product to contain metal compounds.

Detection method

The current detection methods for ethylene phosphorus mainly include automatic potentiometric titration, headspace GC, capillary GC, ion chromatography, etc. The analysis methods of vinyl phosphorus aqueous agent in the national standard are acid-base titration volumetric method and diazomethane methyl ester derivatization-gas spectrometry method. Phosphoric acid, phosphorous acid and the product vinyl phosphorus are mostly used in industrial production.The acid-base titration method is used for detection. This detection method cannot effectively distinguish between acid anhydride and vinyl phosphorus, resulting in a large error between the detection results and the analysis results such as gas chromatography. In 2009, the country issued new vinyl phosphorus standards, requiring the purity of vinyl phosphorus to be no less than 89%, and it was implemented on July 1, 2010.

Iron is an essential trace element for animals. It is an essential component of hemoglobin and myoglobin and interacts with cytochrome enzyme, peroxidase, catalase, acetyl-CoA, and succinate dehydrogenase. , amino silicone oil emulsion xanthine oxidase activity is closely related. Iron participates in the normal transportation of oxygen within the body’s tissues, directly affects the body’s ability and protein metabolism, and also affects the immune function and reproductive performance of the animal body. Ferric pyrophosphate is a yellow-white to yellow-brown crystalline powder with a slight iron odor. Ferric pyrophosphate is an iron nutritional supplement used in milk powder, baby food and general food; it can also be used as a catalyst; as an anti-corrosion pigment.

Structure

Preparation^[2]

A method for producing iron pyrophosphate that improves whiteness and processing performance. The method emulsifies ordinary iron pyrophosphate through microencapsulation technology, and specifically includes the following steps: (1) Ultrafinely pulverized ordinary iron pyrophosphate Ferric phosphate or ordinary undried ferric pyrophosphate wet material is mixed with glyceryl monostearate and calcium carbonate to form a suspension above 80°C, and is emulsified by high-speed shearing and homogenization to obtain a mixed emulsion; (2) The emulsion is spray-dried with an inlet air temperature of 160-190°C and an outlet air temperature of 80-95°C. The spray-dried powder is screened to obtain the target product.

Apply^[3-4]

Iron pyrophosphate has a lighter color and no iron odor, causing no adverse color changes and limited flavor changes to food carriers. It is highly safe, has little gastrointestinal irritation, and has no adverse reactions or side effects. In 1994, the U.S. Food and Drug Administration listed it on the GRAS (Generally Recognized as Safe) list of substances. The bioavailability is high, similar to water-soluble ferrous gluconate. This is mainly due to the fact that ferric pyrophosphate has an additional mineral absorption mechanism. Under the acidic conditions of the stomach (pH 2 to 3.5), iron can be released quickly and in large quantities. , combined with the effects of other synergistic factors in food that promote iron absorption, can achieve higher bioavailability. In addition, it is stable in nature, can withstand high temperatures, is not easily oxidized, will not accelerate fat oxidation, and remains unchanged during storage. Ferric pyrophosphate has a wide range of applications and is mainly used in feed and food additives. It is suitable for flour, biscuits, bread, dry mixed milk powder, rice flour, soy milk powder and other products. It is also used in infant formula foods, health foods, and convenience foods abroad. and functional fruit drinks and other products. Examples of its application are as follows:

1) Prepare an iron pyrophosphate feed additive, which is an iron pyrophosphate salt loaded on a porous mineral material. The content of the iron pyrophosphate salt in the porous mineral material is 1~10% by weight. , its preparation method is to use porous mineral materials as dispersants, load iron pyrophosphate particles synthesized by chemical methods on porous mineral materials, and then dry and crush or spray dry them. The invention has a narrow particle size distribution and better solves the problem of agglomeration of iron pyrophosphate particles. The prepared loaded iron pyrophosphate has the advantage of high bioavailability and can be used as a feed additive for livestock, poultry and aquatic products. Iron supplementation for animals, etc. can also be used to supplement phosphorus in the diet.

2) Prepare a coated iron pyrophosphate composition, in which, relative to 100 parts by mass of iron pyrophosphate, the iron pyrophosphate is decomposed by 0.05 to 1 mass parts of enzyme lecithin and 1 to 10 mass parts of polyoxygen Coated with ethylene sorbitan fatty acid ester or 1 to 10 parts by mass of glycerol fatty acid ester, the composition has a ξ potential of -25 to -39 mV and an average particle size of 1 to 4 μm. The present invention also relates to fermented milk fortified with an iron component, wherein 100 g of fermented milk with an absolute value of ξ potential of 10 mv or less contains 1.0-10 mg of the coated iron pyrophosphate composition in terms of iron derived from iron pyrophosphate. . The coated ferric pyrophosphate composition of the present invention can be used for fermented milk such as yogurt, yogurt drinks, and lactic acid bacteria drinks.

Zinc dihydrogen phosphate is a white triclinic crystal or white solid substance, which is deliquescent and decomposes at 100°C when exposed to water. It contains high levels of free acid and is highly corrosive. It is used as an analytical reagent and preservative and is also used in the glass and ceramic industries.

Research^[3]

Wang Rui et al. synthesized organic phosphonic acid corrosion inhibitors using tetraethylene pentamine, formaldehyde and phosphorous acid as raw materials, compounded with zinc dihydrogen phosphate, and investigated the relationship between organic phosphonic acid corrosion inhibitors and zinc dihydrogen phosphate. The influence of mass ratio, compound system addition amount, corrosion time, corrosion temperature and system pH value on the corrosion inhibition effect of the compound system. The results show that the corrosion inhibition rate of organic phosphonic acid corrosion inhibitors alone is 76.92%. After compounding organic phosphonic acid corrosion inhibitors and zinc dihydrogen phosphate at a mass ratio of 3:1, the corrosion inhibition rate can reach 96.59%. The compound corrosion inhibitor also has the advantages of low dosage, good stability, good temperature resistance and salt resistance.

Preparation^[4]

Preparation of zinc dihydrogen phosphate crystal:

1. Add high-purity zinc oxide into the enamel reactor, add deionized water, and stir into a paste with a solid content of 55-65%; the high-purity zinc oxide refers to a content of 99.99%. Zinc oxide antioxidant 4020 containing Fe, Cu, Ni, Cr, Co, Mn, Ti, V and Pb content less than 0.5ppm;

2. Add the high-purity reagent phosphoric acid with a concentration of 85% into the enamel reactor, add deionized water to prepare a phosphoric acid with a concentration of 75%, raise the temperature to 85-95°C, and slowly stir with sufficient stirring. Add the zinc oxide paste prepared in step 1.2) for reaction. Keep the reactant solution clear and transparent throughout the reaction process. When the pH value is 1 to 2, a zinc dihydrogen phosphate solution is obtained. The high-purity reagent phosphoric acid refers to the content. Phosphoric acid with a content of 99.99%, and metal element impurities Fe, Cu, Ni, Cr, Co, Mn, Ti, V, and Pb are all less than 0.3ppm;

3. Heat the zinc dihydrogen phosphate solution to 135~140℃ and concentrate the reactant to a specific gravity of 1.66~1.70. Put the material into a cooling container. When the temperature drops to 70~75℃, stir and place in the cooling container. Add cooling water to cool the crystallization to room temperature to obtain zinc dihydrogen phosphate crystal;

4. Put the zinc dihydrogen phosphate crystal into a centrifuge to separate the liquid from solid, spin dry and set aside.

Apply^[5]

Zinc dihydrogen phosphate can be used to prepare zinc metaphosphate as an optical glass additive. Put the dried zinc dihydrogen phosphate crystals into a silica ceramic crucible, put the silica ceramic crucible into a calcining furnace, and calcine at a temperature of 950 to 1350°C for 3 to 5 hours to form a glassy partial crucible. Zinc phosphate flows into a container filled with cooling water to form glass slag-like zinc metaphosphate; the main content of silica in the silica ceramic crucible is 99.99%, including metal element impurities Fe, Cu, Ni, Cr, The contents of Co, Mn, Ti, V and Pb are all less than 0.3ppm.

CN201910394813 discloses a metal treatment agent for the surface treatment process of high-anti-corrosion finished auto parts products, which is composed of the following raw materials: boric acid, phosphoric acid, triethanolamine, sericin, vinyltrimethoxysilane, urotropine, and aminotrimethylidene Phosphonic acid, zinc dihydrogen phosphate, tartaric acid and ferrous oxalate; the mass fractions of each raw material are: 20-22 parts of boric acid, 18-20 parts of phosphoric acid, 6-8 parts of triethanolamine, 2-6 parts of sericin, 3-7 parts of vinyltrimethoxysilane, 1-3 parts of methenamine, 1-3 parts of aminotrimethylenephosphonic acid, 2-4 parts of zinc dihydrogen phosphate, 2-8 parts of tartaric acid, 8-8 parts of ferrous oxalate 12 servings. The formula of the invention is simple and practical. The metal workpiece is invaded into the phosphating solution and can be deposited on the surface at normal temperature to form a water-insoluble crystalline phosphate conversion film. The film layer has a microporous structure, is firmly combined with the substrate, and has good properties. Adsorption, lubricity, corrosion resistance, non-adhesion to molten metal and high electrical insulation.