15results about How to "Low free formaldehyde content" patented technology

The invention relates to the technical field of adhesives, and discloses a preparation method and application of a modified urea-formaldehyde resin adhesive. The invention adopts an "alkali-acid-alkali" synthesis process, and adds a cyclic heterocyclic polyphenol flame retardant in the early stage of the reaction of formaldehyde and urea to participate in the synthesis reaction of synthesizing urea-formaldehyde resin. The phenolic hydroxyl group in the flame retardant structure can react with formaldehyde, thereby reducing the free formaldehyde content in the molecule; the structure contains phosphorus and nitrogen synergistic flame retardant elements, which can promote the endothermic dehydration carbonization reaction of hydroxyl-containing compounds and play a positive role in inhibiting the combustion-supporting factors of charcoal materials; the epoxy group of epoxidized lignin can undergo a cross-linking reaction with urea-formaldehyde resin, thereby promoting the reaction of lignin and formaldehyde and reducing the formaldehyde release of plywood; the urea-formaldehyde resin adhesive has low free formaldehyde content and short curing time, and the plywood prepared by using the adhesive has low formaldehyde release, good flame retardant performance and high bonding strength.

The present invention relates to the field of C08L23 / 12, and in particular to an environmentally friendly modified urea-formaldehyde resin and a preparation method and application thereof. The preparation raw materials include, by weight, 8000-12000 parts of formaldehyde, 2500-3000 parts of a first urea, 4000-5000 parts of a second urea, 200-250 parts of a third urea, 50-100 parts of a modifier, 100-200 parts of a triazine-type nitrogen-containing heterocyclic organic compound, 10-15 parts of a first alkali solution, 10-15 parts of a second alkali solution, 5-10 parts of a third alkali solution, 25-35 parts of an acid solution, and 500-800 parts of an auxiliary agent. The urea-formaldehyde resin prepared by the present invention has a free formaldehyde content of less than 0.1% after testing, and is an environmentally friendly resin.

The invention discloses a low-free-formaldehyde sodium glutamate-based gypsum retarder as well as a preparation method and application thereof, and belongs to the technical field of building material admixtures. The preparation method comprises the following steps: by taking sodium glutamate and formaldehyde as raw materials, carrying out an addition reaction at low temperature under a weakly alkaline condition regulated by calcium hydroxide to generate an intermediate; and then heating under an acidic condition to carry out dehydration polycondensation, and neutralizing by negative pressure and lime milk to prepare the sodium glutamate-formaldehyde condensation compound. The invention also discloses a retarder composition containing the condensate and a phosphate / zinc sulfate mixture. According to the invention, the content of free formaldehyde (1t; 300 mg / kg) is obviously reduced through improvement; the problem that the strength of gypsum is reduced due to a traditional retarder is solved by using the chelation of calcium ions and zinc sulfate.

The invention discloses a preparation method of medicinal formaldehyde casein, which comprises the following steps: (1) adding casein and a 0.5 M carbonate aqueous solution into a reaction container, and stirring for dissolving; paraformaldehyde is added; reacting to obtain a reaction solution containing formaldehyde casein; (2) adding ammonia water into the reaction liquid containing the formaldehyde casein, and reacting; filtering and washing a filter cake to obtain a formaldehyde casein crude product; (3) dissolving the formaldehyde casein crude product in an organic solvent, stirring and pulping to obtain a pulping mixed solution; (4) filtering the pulping mixed solution, and washing with an organic solvent to obtain a filter cake; drying under reduced pressure to obtain a dried material; (5) transferring the dried material into a rotary vibration sieve, and sieving by using a 35-mesh sieve; and collecting the material passing through the screen to obtain the medicinal formaldehyde casein. The method has the advantages of simple operation, easily available raw materials, low free formaldehyde content, high casein content, excellent product quality, high operation safety and environmental friendliness, and is suitable for industrial production.

The application belongs to the technical field of retanning agent preparation, and particularly relates to an environment-friendly melamine resin retanning agent and a preparation method thereof. Oxidized starch is prepared by using raw materials including starch, hydrogen peroxide and sodium persulfate; then the oxidized starch is mixed with raw materials such as melamine, dicyandiamide, urea, formaldehyde and sodium sulfamate to prepare a retanning agent prepolymer; finally, sodium alginate intercalated LDHs and polyethylene glycol are added, and after mixed reaction, the environment-friendly melamine resin retanning agent is prepared by spray drying, which can effectively improve the softness and thickening rate of leather and reduce the content of free formaldehyde.

The invention belongs to the technical field of melamine materials, and particularly relates to an environment-friendly melamine composite material and a preparation method thereof. The environment-friendly melamine composite material is prepared from a component A and a component B, wherein the component A is prepared from the following raw materials in parts by mass: 70-80 parts of a modified melamine resin prepolymer, 10-15 parts of a cross-linking agent and 2-5 parts of straws; the component B is prepared from the following raw materials in parts by mass: 70-80 parts of a polycarbonate polyurethane prepolymer and 15-20 parts of a photo-initiation composite material. The environment-friendly melamine composite material is prepared, the content of free formaldehyde in melamine resin is reduced, meanwhile, degradable materials such as straw and eggshells are added, environmental protection is facilitated, and the prepared environment-friendly melamine composite material has good water resistance, stain resistance, heat insulation performance and the like and also has excellent mechanical performance.

The invention relates to the technical field of furan resin, in particular to high-strength furan resin as well as a preparation method and application thereof. The high-strength furan resin comprises the following components in parts by weight: 35-60 parts of furfuryl alcohol, 15-25 parts of formaldehyde, 5-10 parts of urea, 1-3 parts of a formaldehyde reducing agent and 3-5 parts of a cross-linking agent. The high-strength furan resin provided by the invention is high-performance furan resin with high mechanical strength, excellent moisture resistance and low free formaldehyde release, and has a wide application prospect in the field of casting. The introduced cross-linking agent can improve the cross-linking density, improve the tensile strength and avoid brittle failure. In addition, carboxyl in molecules of the cross-linking agent can adjust polarity and compatibility of the system, phase separation in storage and use processes is inhibited, and the storage stability of the resin is remarkably improved. The formaldehyde reducing agent introduced by the invention can be subjected to nucleophilic addition reaction with free formaldehyde in a system, so that the formaldehyde content can be efficiently and enduringly reduced, and the production and use environment can be improved.

According to the preparation process of the environment-friendly ENF-grade fireproof plate, firstly, glue solution urea-formaldehyde resin and melamine formaldehyde resin are modified, then the glue solution urea-formaldehyde resin and the melamine formaldehyde resin are mixed according to the proportion of 5: 5 to form mixed glue solution, and the prepared fireproof plate is good in surface abrasion resistance and bonding strength. And the plant negative oxygen ion extracting solution is added, so that the prepared fireproof plate has the effects of reducing aldehyde and releasing negative oxygen ions. Then, chitosan is used for modifying glass fibers, then the adhesive film paper, the non-woven fabric and the modified glass fibers are impregnated, the fireproof plate can release formaldehyde capable of being volatilized under the high-temperature effect of hot pressing, and the remaining formaldehyde is purified through the formaldehyde purifying function of the newly-added plant negative oxygen ion extracting solution; and finally, the formaldehyde emission of the produced fireproof plate reaches the ENF level.

The application discloses a preparation method of hydrogenated aldehyde ketone resin without free formaldehyde, belongs to the technical field of aldehyde ketone resin synthesis, and aims to solve the technical problems of high free formaldehyde content, and further improved hydroxyl value stability and transparency in the hydrogenated aldehyde ketone resin in the prior art, and specifically comprises the following steps: under the protection of an inert gas atmosphere, phenylacetone, polyformaldehyde and a solvent are mixed and stirred, the reaction system is heated to 60-75 DEG C, and an inorganic alkali is added into the reaction system. The application is characterized in that the basic aldehyde ketone resin solution prepared by condensation of polyformaldehyde and phenylacetone in a water-free environment with a nickel catalyst is catalytically hydrogenated, not only the hydrogenated aldehyde ketone resin with stable hydroxyl value and extremely low colority is effectively obtained, but also the free formaldehyde content in the hydrogenated aldehyde ketone resin is effectively reduced, and the wide applicability of the hydrogenated aldehyde ketone resin in high-end coatings, adhesives and electronic materials is improved.

The invention discloses a preparation method of medicinal formaldehyde casein, comprising the steps of (1) adding casein and 0.5M carbonate aqueous solution into a reaction vessel, stirring and dissolving; adding paraformaldehyde; reacting to obtain a reaction solution containing formaldehyde casein; (2) adding ammonia water into the reaction solution containing formaldehyde casein, reacting; filtering, washing the filter cake with water, and obtaining a crude formaldehyde casein product; (3) dissolving the crude formaldehyde casein product in an organic solvent, stirring and beating to obtain a beating mixed solution; (4) filtering the beating mixed solution, washing with an organic solvent, obtaining a filter cake; drying under reduced pressure to obtain a dry material; (5) transferring the dry material into a rotary vibrating screen, sieving with a 35-mesh screen; collecting the material passing through the screen, namely, the medicinal formaldehyde casein. The invention is simple to operate, has readily available raw materials, low free formaldehyde content, high casein content, excellent product quality, high operational safety, environmental friendliness, and is suitable for industrial production.

This invention discloses a water-resistant starch adhesive and its preparation method. The adhesive is composed of the following raw materials in parts by weight: 380-420 parts starch, 15-18 parts polyvinyl alcohol, 4-6 parts urea, 0.5-1.5 parts urea-formaldehyde resin, 1-3 parts borax, 10-12 parts sodium hydroxide, and 1000-1200 parts water. In the preparation process, polyvinyl alcohol, urea, and a trace amount of urea-formaldehyde resin are first pre-condensed at 65-75°C under acidic conditions (pH 4.2-4.8) to generate a polyvinyl alcohol-urea condensate. Then, the condensate is combined with starch and other raw materials in a one-pot process to complete gelatinization and final product formulation. This invention uses the polyvinyl alcohol-urea condensate to effectively replace more than 90% of the conventionally used commercial urea-formaldehyde resin, resulting in extremely low free formaldehyde content, a delamination time of 27-28 hours, and an adhesive strength of 850-860 N / m. The overall raw material cost is reduced by approximately 13%, and the process is simple, making it suitable for the production of corrugated cardboard adhesives.

This invention discloses a high-strength, flame-retardant, and moisture-proof furniture board and its preparation method, relating to the field of furniture board technology. The board produced by this invention uses bamboo as raw material, which is processed into wood shavings. Urea-formaldehyde resin, nanocellulose made from waste materials during bamboo shavings processing, a waterproofing agent, and a flame retardant are added, and the board is then hot-pressed and laid together. Hydroxymethylated sodium lignosulfonate and melamine are added to the urea-formaldehyde resin to improve its performance. The board is laid by horizontally laying the core layer of wood shavings and vertically laying the surface layer of wood shavings, followed by a surface-core-surface layer arrangement to obtain a furniture board.

The invention belongs to the technical field of polymer adhesives, and relates to a preparation process of melamine formaldehyde resin with high viscosity and low free formaldehyde, which comprises the following steps: fully stirring formaldehyde and water, regulating the pH value to 9.0-9.5 by using a sodium hydroxide solution, and controlling the temperature to 25-30 DEG C; adding polyvinyl alcohol, heating to 50 DEG C, and preserving heat for 10-30 minutes; sequentially adding melamine and an environment-friendly accelerant, stirring, heating to 90 DEG C, keeping the temperature for 10 minutes, and adding residual formaldehyde; and keeping the temperature at 92-95 DEG C, reacting for 10 minutes, measuring a mist point, slightly cooling when the mist point reaches 20 DEG C, cooling when the water-soluble ratio is detected to be 1: 2.5, naturally cooling to 60 DEG C, adding urea, cooling to normal temperature, and discharging glue. The prepared melamino-formaldehyde resin is also applied to preparation of impregnated paper. The polyvinyl alcohol can improve the viscosity of the resin, reduce the brittleness of the cured glue and improve the yield of the impregnated paper; by adding the environment-friendly accelerant and urea, the plasticity of the resin is improved, the resin is fully reacted, and the content of free formaldehyde is reduced.

The invention provides a self-flame-retardant organic phase change energy storage composite material and a preparation process thereof, and belongs to the technical field of preparation of organic phase change energy storage materials. The preparation process comprises the following steps: preparing a novel flame retardant intermediate product; preparing a novel flame retardant; preparing the modified melamine formaldehyde; and preparing the organic phase change energy storage composite material. The microcapsule organic phase change energy storage composite material with a multi-layer structure is prepared, the defect of low thermal conductivity is overcome by taking the methanol modified melamino-formaldehyde as a shell and adding the conductive filler, the prepared organic phase change energy storage composite material has good thermal conductivity and thermal stability, and the novel flame retardant is added, so that the composite material has good thermal conductivity and thermal stability. The organic phase change energy storage composite material has good flame retardant property.

The invention relates to the technical field of melamine adhesives, and discloses a melamine adhesive with a long storage period and a preparation method thereof. On the basis of the melamine adhesive, the oxidation mixing agent, the alcohol solution and the stabilizer are introduced, so that the storage stability of the adhesive is improved, the storage time of the melamine adhesive is prolonged, and the formaldehyde emission is reduced.