Preparation method of high solid content expandable melamine modified urea resin

The invention discloses a preparation method of high solid content expandable melamine modified urea resin. The preparation method is as follows: a non-dehydration preparation process is adopted, paraformaldehyde is depolymerized under the alkaline condition to obtain high concentration formaldehyde solution, and the high concentration formaldehyde solution reacts with urea and melamine to directly prepare the high solid content expandable melamine modified urea resin. The solid content of the prepared urea resin is 70%-80%, the viscosity is 800-1200MPa and the content of free formaldehyde is 0.1%-0.25%. The apparent density of the melamine modified urea resin foam material obtained through foaming is up to 0.03-0.05g/cm<3>, the oxygen index is 50%-70%, the foam material can meet the requirements of the new building material with light weight and fire resistance; and the invention provides a new way for the development and utilization of the fire resistant and environmentally friendly urea ...

CHINESE BLACK WATTLE TANNING GUM USING ACTIVE PHYNOL-UREA-FORMALDYDE RESIN AS CROSS-LINKER

This invention relates to a Chinese acacia tannic adhesive used to make outdoor veneer board. In its preparing process, an active PUF (phenol-Urea-Formaldehyde) resin with low molecular weight is used as both cross-linking and strengthening agents. Acacia extract is dissolved in water to prepare a solution with 40-50% concentration, which is uniformly mixed with said PUF resin and wheat flour to obtain a tannic adhesive. The PUF resin contains a certain quantit of free formaldehyde and more hydroxy methyl. The veneer board made up by use of said adhesive according to common used pressing technology with phenolic adhesive can meet the strength requirement of class-one veneer board in GB9846.4-88 standard, but has lower cost.

Preparation of alkali lignin-phenolic composite adhesive for timber industry

The invention relates to a method for preparing an alkali lignin-phenolic resin composite adhesive for wood adhesive, which comprises the steps that hydroxymethylation alkali lignin is prepared; and the alkali lignin-phenolic resin composite adhesive is prepared. The method adopts hydroxymethyl reaction to improve the activation of alkali lignin; the hydroxymethylation alkali lignin is prepared; lignin is selected and added by three batches; the batch addition of the lignin can achieve the function of adjusting the degree of the hydroxymethyl reaction, contribute to the realization of the hydroxymethyl reaction, reduce the condensation reaction between lignin hydroxymethyls and achieve the aim of the farthest activation of the lignin. In the synthetic process, the PH value and viscosity in the reaction are strictly controlled; and the batch feeding method is used to carry out orderly and rapid hydroxymethyl reaction. As the lignin has huge molecular weight, large space steric hindrance ...

Method for manufacturing E0 level wood veneer

The invention provides a preparation method of plywood of E0 grade. The urea formaldehyde resin adhesive has an advantage of simple preparation technology, good reproducibility, lower cost and long store time. By using the urea formaldehyde resin adhesive, the plywood/three-ply board/overlaying panel/multilayer board accord with the requirements of plywood of E0 in terms of the bonding strength and the formaldehyde emission. The method in the invention has the advantages that: the preparation of the urea formaldehyde resin adopts the alkali-acid-alkali traditional craft; the urea and the melamine are added in three times; the urea is added in three times which adjusts the quality of the resin molecule; especially, the urea, which is added in the second time, not only degrades and resets the large molecules but also decreases the content of the ether linkage and reduces the release of the formaldehyde; during the composite process, the pH value in the condensation polymerization is rigidly ...

Preparation method of high solid content expandable melamine modified urea resin

The invention discloses a preparation method of high solid content expandable melamine modified urea resin. The preparation method is as follows: a non-dehydration preparation process is adopted, paraformaldehyde is depolymerized under the alkaline condition to obtain high concentration formaldehyde solution, and the high concentration formaldehyde solution reacts with urea and melamine to directly prepare the high solid content expandable melamine modified urea resin. The solid content of the prepared urea resin is 70%-80%, the viscosity is 800-1200Mpa and the content of free formaldehyde is0.1%-0.25%. The apparent density of the melamine modified urea resin foam material obtained through foaming is up to 0.03-0.05g/cm<3>, the oxygen index is 50%-70%, the foam material can meet the requirements of the new building material with light weight and fire resistance; and the invention provides a new way for the development and utilization of the fire resistant and environmentally friendly urea ...

Preparation method of phenol-urea-formaldehyde resin adhesive for E0-grade outdoor plywood

MANUFACTURING METHOD FOR HARD FIBERBOARD BY USE OF CONDENSED TANNIN EXTRACTS

The present invention relates to a manufacturing process of hard fibre-board by use of condensed tannin extracts as glue stock. The present invention is characterized by that it uses condensed tannin extracts as glue stock to make hard fibre-board. it not only can ensure the quality of fibre-board, but also the volatile phenol content of waste water from the production of fibre-board is up to the discharge standard defined in the National Standard GB8978-88.

Wood fiber reinforced flame retardant foam composite plate and manufacturing method thereof

The invention relates to a wood fiber reinforced flame retardant foam composite plate and a preparation method thereof. The external layer of the composite plate is a wood panel, and the foam core plate in the internal layer is a wood fiber reinforced phenol formaldehyde foam material or a melamine modified formaldehyde foam material. The wood fiber is treated by a coupling agent. The invention further relates to a manufacturing method of the plate. The wood panel is adhered to the external layer panel of the foam core plate. The plate can be manufactured by performing lamination thermal composition on the materials by using an adhesive, and also can be manufactured by directly foaming between fixed dual-layer panels. The foam core plate uses wood fiber reinforced phenol formaldehyde foam or melamine modified formaldehyde foam material. The flame retardant performance can accord with the specified standard. The foam core plate is flame retardant and small in smoke amount, generates no harmful ...

Preparation of urea-melamine-formaldehyde resin adhesive for E0 floor

The invention discloses a method for preparing a urea-melamine-formaldehyde resin adhesive for an E0-level floor. In the first step, formaldehyde solution, melamine and urea are mixed, the pH value of the mixture is regulated, the temperature is raised to 80-95 DEG C, and the reaction lasts 40-60 minutes, wherein, the mol ratio between formaldehyde and the total amount of the urea and the melamine is 2.05-2.12 : 1; in the second step, the pH value is regulated to be 5.0-6.0, and the reaction is underway till the turbidity point; in the third step, the pH value is regulated to be 6.0-6.9, the urea and the melamine are added, and the mol ratio between the formaldehyde and the total amount of the urea and the melamine which are added in the first step and the second step is 1.48-1.74 : 1, and the reaction lasts 30-70 min at a temperature of 90 DEG C; in the fourth step, the pH value is regulated to be 7.5-9.0, the melamine is added, and the reaction lasts 20-80 min at a temperature of 80-90 ...

Preparation method of Chinese black wattle tannin gum using active phenolic resin as cross linker

Method of preparing alkali lignin modified phenolic resin

A method for preparing alkali lignin modified phenol-formaldehyde resin comprises the following steps: phenol, a first batch of formaldehyde solution, alkali lignin, metal oxide and dilution water are added into a reactor; a second batch of formaldehyde solution is added into the reactor; and a third batch of formaldehyde solution and a first batch of alkaline solution are added, formaldehyde trapping agent and a second batch of alkaline solution are added, and then material is discharged after cooling. The invention adopts the copolymerization technique to prepare an alkali lignin phenol formaldehyde adhesive, lignin and the phenol are added simultaneously, obtained hydroxymethylated lignin is reacted with hydroxymethyl phenol, a small part of the obtained hydroxymethylated lignin participates in the polycondensation of the hydroxymethyl phenol to form a main chain, and a large part of the obtained hydroxymethylated lignin forms branch chains through graft copolymerization, therefore, ...

Heat treatment method for prolonging service life of heavy drill rod made of 42CrMo material

The invention discloses a heat treatment method for prolonging the service life of a heavy drill rod made of a 42CrMo material, which is characterized in that a national standard 42CrMo raw material added with a V element is adopted to manufacture the drill rod, and a heat treatment mode of quenching, tempering with a sodium nitrate solution and secondary tempering with the sodium nitrate solution at the tail part of the drill rod is adopted. Quenching, heating to 850-870 DEG C, keeping the temperature after uniform temperature, discharging from the furnace, and cooling with water; tempering with a sodium nitrate solution, namely putting the whole drill rod quenched to the room temperature into the sodium nitrate solution heated to 400 +/-5 DEG C for heat preservation, discharging from the furnace, and performing air cooling; and carrying out secondary tempering on the tail part of the drill rod by using a sodium nitrate solution, vertically putting 20-30mm of the tail part of the drill ...

Preparation method of phenol-urea-formaldehyde resin adhesive for E0-grade outdoor plywood

The invention discloses a preparation method of a phenol-urea-formaldehyde resin adhesive for E0-grade outdoor plywood. The preparation method comprises the following steps: step 1, mixing phenol, a formaldehyde solution and urea, adding a catalyst, and rising the temperature for reaction; step 2, adding the formaldehyde solution and urea which can also be added in the step 3 again, adding an alkali metal hydroxide solution for reaction; step 3, continuing to add the formaldehyde solution and the alkali metal hydroxide solution, if the urea is not added in the former step, adding the urea forreaction at the moment; and step 4, adding the urea and the alkali metal hydroxide solution for reaction until the viscosity is 1.5-2.0 seconds measured by a gardner-holdt tube reverse bubble measurement method, and then discharging. The adhesive-making process is mild in reaction and is easy to control, repeatability is good, and the storage life of the adhesive is more than 30 days. The strength of ...

Wood fiber reinforced inflaming retarding foam material and machining method thereof

The invention discloses a wood fiber reinforced inflaming retarding foam material and a machining method thereof. The composite foam material is prepared from the following components in parts by weight: 40-95 parts of foaming flame-retarded resin, 0.1-8 parts of curing agent, 0.5-8 parts of surfactant, 1-50 parts of wood fiber and 0.5-10 parts of flexibilizer. The wood fiber is treated by using a coupling agent and then dried, and the coupling agent accounts for 0.15-0.5 percent of the mass of the wood fiber. A naturally expanded foaming method or die foaming method is adopted. The wood fiber reinforced inflaming retarding foam material can be widely applied to fields of insulation of building outer wall bodies, architectural ornament, traffic vehicles, water ships, aerospace, electromechanical equipment, industrial sound absorption, heat preservation and shock absorption and the like, and is a composite foaming material with actual application value.

CHINESE BLACK WATTLE TANNIN GUM USING ACTIVE BAKELITE AS CROSS-LINKER

This invention relates to a process to prepare Chinese acacia tannic adhesive used for making outdoor veneer board, in which active phenolic resin with low molecular weight, instead of paraform, is used as both cross-linking and strengthening agents. It features the preparation of active phenolic resin which has low molecular weight and 1/2.2-1/3.4 of P/F molar ratio and contains a certain quantity of free formaldehyde and more hydroxy methyl. The veneer board made up by use of said adhesive according to the common used pressing technology with phenolic adhesive can meet the strength requirement of class-one veneer board in GB9846.4-88 standard, but has lower cost.

Preparation method of Chinese black wattle tanning gum using active phenol-urea-formol resin as cross-linker

Preparation of alkali lignin-phenolic composite adhesive for timber industry

The invention relates to a method for preparing an alkali lignin-phenolic resin composite adhesive for wood adhesive, which comprises the steps that hydroxymethylation alkali lignin is prepared; and the alkali lignin-phenolic resin composite adhesive is prepared. The method adopts hydroxymethyl reaction to improve the activation of alkali lignin; the hydroxymethylation alkali lignin is prepared; lignin is selected and added by three batches; the batch addition of the lignin can achieve the function of adjusting the degree of the hydroxymethyl reaction, contribute to the realization of the hydroxymethyl reaction, reduce the condensation reaction between lignin hydroxymethyls and achieve the aim of the farthest activation of the lignin. In the synthetic process, the PH value and viscosity in the reaction are strictly controlled; and the batch feeding method is used to carry out orderly and rapid hydroxymethyl reaction. As the lignin has huge molecular weight, large space steric hindrance ...

Thermal treatment process capable of improving low-temperature impact work of ASTM508Gr2 steel

The invention relates to a thermal treatment process capable of improving low-temperature impact work of ASTM508Gr2 steel. The thermal treatment process adopts a thermal treatment mode of normalization, quenching and tempering, and specifically comprises the following steps of: firstly, heating to be 640-660 DEG C, keeping the temperature, further raising the temperature to be 880-920 DEG C, keeping the temperature, and cooling down in a blowing mode; heating to be 640-660 DEG C, keeping the temperature, further raising the temperature to be 870-900 DEG C, keeping the temperature, rapidly reducing the temperature to be within 780-820 DEG C, keeping the temperature for 1-3 hours, discharging out of a furnace and quenching, wherein the quenching medium is water; heating to be 300-350 DEG C, keeping the temperature, further raising the temperature to be 670-690 DEG C, keeping the temperature, and cooling down by using #20 mechanical oil. Through normalization, alloy elements can be subjected ...

Wood fiber reinforced inflaming retarding foam material and machining method thereof

The invention discloses a wood fiber reinforced inflaming retarding foam material and a machining method thereof. The composite foam material is prepared from the following components in parts by weight: 40-95 parts of foaming flame-retarded resin, 0.1-8 parts of curing agent, 0.5-8 parts of surfactant, 1-50 parts of wood fiber and 0.5-10 parts of flexibilizer. The wood fiber is treated by using a coupling agent and then dried, and the coupling agent accounts for 0.15-0.5 percent of the mass of the wood fiber. A naturally expanded foaming method or die foaming method is adopted. The wood fiber reinforced inflaming retarding foam material can be widely applied to fields of insulation of building outer wall bodies, architectural ornament, traffic vehicles, water ships, aerospace, electromechanical equipment, industrial sound absorption, heat preservation and shock absorption and the like, and is a composite foaming material with actual application value.

Method of preparing alkali lignin modified phenolic resin

A method for preparing alkali lignin modified phenol-formaldehyde resin comprises the following steps: phenol, a first batch of formaldehyde solution, alkali lignin, metal oxide and dilution water are added into a reactor; a second batch of formaldehyde solution is added into the reactor; and a third batch of formaldehyde solution and a first batch of alkaline solution are added, formaldehyde trapping agent and a second batch of alkaline solution are added, and then material is discharged after cooling. The invention adopts the copolymerization technique to prepare an alkali lignin phenol formaldehyde adhesive, lignin and the phenol are added simultaneously, obtained hydroxymethylated lignin is reacted with hydroxymethyl phenol, a small part of the obtained hydroxymethylated lignin participates in the polycondensation of the hydroxymethyl phenol to form a main chain, and a large part of the obtained hydroxymethylated lignin forms branch chains through graft copolymerization, therefore, ...

Method for manufacturing E0 level wood veneer

Preparation method for PTUF resin adhesive used by E0-level outdoor plywood

The invention relates to a preparation method for PTUF resin adhesive used by E0-level outdoor plywood. The preparation method comprises the following steps: step 1: stirring and adding PT activate fluid and a first batch of urea U (1); adding a first batch of formalin F (1); increasing temperature to 88-92 DEG C; reacting for 40 min; step 2: adding a second batch of urea U (2); adding a second batch of formalin F (2); gradually adding a first batch of NaOH solution NaOH (1) within 30 min; reacting for 70 min at a temperature of 85-88 DEG C; step 3: adding a third batch of urea U (3); adding a third batch of formalin F (3); gradually adding a second batch of NaOH solution NaOH (2) in 20 min; reacting at a temperature of 80-85 DEG C until the viscosity is 40-50 s; detecting the viscosity through a 70 DEG C coating-4 cup; step 4: adding a fourth batch of urea U (4); adding a third batch of NaOH solution NaOH (3); reacting for 10-20 min at a temperature of 80-85 DEG C; reducing temperature ...

Manufacturing method for hard fiberboard by use of condensed tannin extracts