17 results about "Biurea" patented technology

The invention provides a preparation method of an ADC foaming agent for improving foaming pore density, which comprises the following steps: step 1, mixing a modified inorganic nucleating agent with water according to a predetermined mass ratio, adding a dispersing agent, and uniformly mixing to prepare uniform and stable suspension slurry to prevent agglomeration of the nucleating agent; 2, when the conversion rate of the biurea reaches 80%-85%, adding the suspension slurry, so that the inorganic nucleating agent is uniformly attached to the surface of the ADC crystal; and 3, continuing the oxidation reaction until the biurea conversion rate reaches 92% or above, and then washing, centrifuging and drying to obtain the ADC foaming agent. The ADC foaming agent for improving the foaming pore density is prepared by the method. The inorganic nucleating agent is added in the stage of preparing the ADC foaming agent, and compared with the inorganic nucleating agent added in the subsequent foam material preparation process, the density of foaming pores can be remarkably improved.

The invention provides a method for generating biurea through a condensation reaction of hydrazine hydrate and urea, which comprises the following steps: a first stage: mixing urea and a hydrazine hydrate solution in proportion, and continuously adding into a first condensation kettle; and in the second condensation kettle, setting a higher pressure and temperature range, supplementing a proper amount of urea to ensure the reactant concentration, adding the residual ammonium sulfate catalyst, and continuing to accelerate the reaction. The method has the advantages of high yield, high purity, energy conservation and the like.

The invention provides a method for controlling an oxidation reaction of an ADC (azodicarbonamide) foaming agent by intermittently introducing chlorine, which comprises the following steps: dissolving biurea and water in a reaction kettle according to a solid-to-liquid ratio of 1: (2-3) to obtain biurea slurry; adding halide into the biurea slurry as an oxidation aid, and introducing chlorine into the reaction kettle for reaction under the condition that the temperature in the reaction kettle is adjusted to 10-40 DEG C; when the reaction is carried out to 85%-90%, chlorine introduction is stopped, polyoxyethylene stearate is added into the reaction kettle to serve as a surfactant, and the mass ratio of reactants in the reaction kettle to polyoxyethylene stearate is 100: (0.01-0.1); continuously introducing chlorine into the reaction kettle, and controlling the chlorine to be intermittently introduced into the reaction kettle until the reaction is finished; the chlorine introduction time is 1-30 min / time, and the intermittent time is 1-40 min / time; filtering and cleaning reactants in the reaction kettle step by step, and drying, crushing, grading and the like after the pH value of the reactants reaches 6.5 to obtain a finished product ADC foaming agent. The end point of the ADC oxidation reaction can be effectively controlled, and excessive chlorine is prevented from decomposing the product.

The invention provides a production method for improving the yield of an ADC foaming agent, which comprises the following steps: fully mixing urea and hydrazine hydrate in a premixing tank according to the mass ratio of (2.4-3.5): 1 to obtain a premixed solution; continuously adding the premixed solution into the condensation reaction kettle, dropwise adding concentrated hydrochloric acid with the concentration of more than 31% until the pH value of the materials in the condensation reaction kettle is 2.0-3.0, heating the materials in the condensation reaction kettle to 90-110 DEG C, and carrying out condensation reaction; adjusting the gas phase ammonia partial pressure in the condensation reaction kettle according to the progress of the condensation reaction; when the concentration of hydrazine hydrate in the condensation reaction kettle is lower than 1g / L, stopping the condensation reaction, carrying out solid-liquid separation and washing on materials in the condensation reaction kettle to obtain a biurea solid, and carrying out an oxidation process on the biurea solid to obtain the ADC foaming agent. According to the production method for improving the yield of the ADC foaming agent, the self-condensation reaction of urea can be effectively inhibited, and the yield of the ADC foaming agent is improved.

The present application relates to the field of functional nutritional fortifier micro-encapsulation technology, and discloses a kind of micro-encapsulated spray-dried 25-hydroxyvitamin D3 and its preparation method.The microcapsule is composed of 25-hydroxyvitamin D3, synergistically modified embedding matrix material, isophorone diisocyanate derived biuret small molecule and various additives, wherein the synergistically modified embedding matrix material is formed by casein and hydroxypropyl-beta-cyclodextrin under the action of covalent bridging, aromatic amine crosslinking network and boron-nitrogen synergistic coordination to form a dynamic covalent-supramolecular coupled multi-network structure.Through the synergistic effect of the multi-network structure and the interface self-assembly small molecule, the multiple confinement and interface stable regulation of 25-hydroxyvitamin D3 are realized.The preparation method includes the construction of synergistically modified embedding matrix material, emulsification and spray-drying steps.The microcapsule product obtained by the present application has the advantages of high embedding rate, strong thermal stability, excellent antioxidant performance and controllable release behavior, and is suitable for food fortification and feed additive fields.

The invention relates to the field of chemical production, in particular to a green production method of an ADC foaming agent. The green production method of the ADC foaming agent comprises the following steps: mixing biurea, an acidic medium aqueous solution and a catalyst to obtain slurry; placing the slurry in a reactor for reaction; after the reaction is finished, carrying out solid-liquid separation on a reaction product, collecting a solid phase, washing and drying to obtain an azodicarbonamide product; wherein in the step S2, the tail gas which does not participate in the reaction is guided out, and after the oxidizing gas is supplemented, the tail gas is introduced into the reactor again to participate in the reaction; the liquid-phase mother liquor obtained through separation in the step S3 is subjected to pH adjustment, and is completely or partially recycled to the step S1 to be used for preparing the slurry. The green production method of the ADC foaming agent provided by the invention is environment-friendly, green production is realized from the source, the production efficiency and economy are greatly improved, and the product quality is excellent.

The invention relates to the field of foaming polymer materials, and discloses a foaming master batch raw material composition, a foaming master batch using the raw material composition, a preparation method of the foaming master batch, an EPDM / PP TPV micro-foaming material composition, an EPDM / PP TPV micro-foaming material, and a preparation method and application of the EPDM / PP TPV micro-foaming material. The raw material composition for the foaming master batch comprises a base material, extending oil, a first foaming agent, a second foaming agent, an auxiliary foaming agent and a surfactant, the first foaming agent is one or more of azodicarbonamide, 4, 4 '-oxybisbenzenesulfonyl hydrazide, trihydrazino-s-triazine and biurea, and the second foaming agent is an inorganic foaming agent. The EPDM / PP TPV micro-foaming material prepared by using the foaming master batch disclosed by the invention is lower in foaming agent consumption and higher in tensile strength and elongation at break under the same foaming ratio.

The presently claimed invention relates to dielectric polishing composition comprising (A) surface - modified colloidal silica particles comprising a negatively - charged group on the surface of the particles, wherein the surface-modified colloidal silica particles have a negative charge, a particle size of from 5 nm to 200 nm, and a zeta potential < -35 mV at a pH in the range of from ≥ 2.0 to ≤ 4.5; (B) at least one buffering agent selected from L-arginine, lysine, or histidine; (C) at least one iron (III) oxidizer; (D) at least one pH adjusting agent selected from 2-amino-2-methyl- propan-1-ol or phosphoric acid and salts thereof; (E) at least one stabilizer; (F) at least one corrosion inhibitor selected from formamidine sulfinic acid, L- cysteine, ethylene thiourea, thiourea, N-(4-pyridyl)thiourea), N-(n-propyl)thiourea, cysteine sulfinic acid, 4-aminobenzene-1- sulfinic acid, N-(2-mercaptopropionyl)glycine, 2-oxooxane-4-sulfonic acid, L-cysteic acid, 2- amino-thiobiuret, L-methionine, or homocysteine; and (G) an aqueous medium, wherein the pH of the composition is in the range of from ≥ 2.0 to ≤ 5.0.

The invention provides a method for directly preparing biurea from benzophenonetazine, which comprises the following steps of: adding an acid catalyst into a mixed solution of benzophenonetazine, urea and an organic solvent, heating for reaction, and finally centrifugally separating to directly obtain the biurea. The benzophenonetazine and the urea are used as raw materials, the raw materials are dissolved in the reaction solvent, the reaction product biurea is not dissolved in the reaction solvent, the product is easy to separate and purify, inorganic salt and ammonia nitrogen wastewater are not generated in the reaction, the technological process is simple, and the method has the advantages of being easy to implement industrially and remarkable in economic benefit.

The present invention provides a non-fire-spreading grease composition which contains: (a) as a thickening agent, a diurea compound that is represented by formula (1) R1-NHCONH-R2-NHCONH-R3 (wherein R2 represents an aromatic hydrocarbon group having 6 to 15 carbon atoms, R1 and R3 may be the same or different and each represent an aliphatic hydrocarbon group having 8 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 15 carbon atoms, and the proportion of the aliphatic hydrocarbon group in the total of R1 and R3 is 50-100 mol%); (b) a base oil that has a kinematic viscosity at 40°C of 300 mm2 / s or more; (c) at least one substance that is selected from the group consisting of rice wax, carnauba wax, and montanic acid derivatives; and (c) at least one substance that is selected from the group consisting of organic sulfonic acid metal salts, sodium sebacate, and glycerol.

The invention relates to the technical field of ADC preparation, in particular to an alkaline ADC foaming agent condensation mother liquor treatment system which comprises a biurea reactor, a centrifugal machine, an HDCA mother liquor tank, a first desorption tower, a second desorption tower and a hydrolysis tower. Liquid obtained after products of the biurea reactor are centrifuged is communicated with an HDCA mother liquor tank through a pipeline, two outlet pipelines of the HDCA mother liquor tank are communicated with a urea dissolving tank and a first desorption tower respectively, a second desorption tower is arranged on the lower portion of the first desorption tower, a low-pressure steam pipeline is arranged on the lower portion of the second desorption tower, and the top of the first desorption tower is communicated with an ammonia recovery procedure through a pipeline. A liquid outlet of the first desorption tower is communicated with the hydrolysis tower through a pipeline, the upper part of the hydrolysis tower is communicated with the lower part of the first desorption tower through a pipeline, and the side part of the hydrolysis tower is provided with a medium-pressure steam pipeline. The system can hydrolyze the mother liquor, ammonia in the mother liquor is recycled, the conductivity of the treated liquid wastewater is smaller than 10 us / cm < 2 >, the content of ammonia nitrogen is smaller than 10 ppm, the content of urea is smaller than 100 ppm, and the system is energy-saving and environment-friendly.

The application provides a preparation method of azodicarbonamide, comprising the following steps: S1, uniformly mixing hydrogen peroxide solution with a stabilizer and a cocatalyst to obtain a first reaction solution; S2, mixing biurea, water and a catalyst to obtain a second reaction suspension; S3, dropwise adding the preheated first reaction solution into the second reaction suspension to perform an oxidation reaction, and obtaining azodicarbonamide after the reaction is completed; the stabilizer in the step S1 is one or more of 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid, 8-hydroxyquinoline, sodium dihydrogen pyrophosphate and nitrilotrimethylene phosphoric acid. In the application, the selection of the hydrogen peroxide stabilizer and the cocatalyst can reduce the decomposition speed of hydrogen peroxide and improve the utilization rate of hydrogen peroxide, so that the loss of raw materials is reduced, the cost of raw materials is reduced, and the production profit is improved.

The invention provides a method for producing an ADC foaming agent by oxidizing HDCA with nitrogen dioxide. The method comprises the following steps: preparing a biurea solid and a sulfuric acid solution into slurry, continuously introducing nitrogen dioxide gas, and oxidizing to prepare azodicarbonamide. The method has the advantages that the water phase can be recycled, other catalysts are not added, and enrichment of inorganic salt in the wastewater can be effectively avoided; meanwhile, the nitrogen oxide gas can be recycled, and high-purity nitrogen dioxide is regenerated through oxygen supplementation in a water-free and acid-free environment. Based on the characteristics, the method does not generate waste water, does not enrich salts, and reduces the process flow.

The application provides a preparation method of an ADC foaming agent for improving foaming cell density, which comprises the following steps: step 1: mixing a modified inorganic nucleating agent and water according to a predetermined mass ratio, adding a dispersing agent, uniformly mixing, and preparing a uniform and stable suspension slurry to prevent the nucleating agent from agglomerating; step 2: when the conversion rate of biurea reaches 80%-85%, the suspension slurry is added, and the inorganic nucleating agent is uniformly attached to the surface of the ADC crystal; step 3: continuing the oxidation reaction until the conversion rate of biurea reaches more than 92%, and then performing washing, centrifugation and drying to obtain the ADC foaming agent. The ADC foaming agent for improving foaming cell density is prepared by the above method. In the preparation process of the ADC foaming agent, the inorganic nucleating agent is added, compared with adding the inorganic nucleating agent in the subsequent preparation process of the foaming material, and the foaming cell density can be significantly improved.

The application provides a preparation method of azodicarbonamide, which comprises the following steps: step (1), mixing biurea, a ferrous compound catalyst and water according to a certain proportion to prepare a biurea suspension; step (2), adjusting the pH value of the biurea suspension prepared in step (1) to 2-6, and heating the biurea suspension with the pH value of 2-6 to 50-100 DEG C to obtain a second suspension; step (3), slowly dropping hydrogen peroxide solution into the second suspension obtained in step (2) to react for a certain time to obtain solid azodicarbonamide; and step (4), separating and washing the solid azodicarbonamide prepared in step (3), so that azodicarbonamide is obtained. In the application, hydrogen peroxide is used as an oxidant, a ferrous compound is used as a catalyst, and the ferrous compound and hydrogen peroxide are reacted, so that biurea can be efficiently oxidized to obtain azodicarbonamide, there is no risk of harmful gas leakage, no waste salt is generated, the preparation process is clean and green.

The grease composition contains a base oil, a diurea compound as a thickener, and at least one wax selected from the group consisting of rice wax, lanolin wax, carnauba wax, and castor wax.