Modified urea-formaldehyde resin with low content of formaldehyde, and preparation method and application thereof

A urea-formaldehyde resin and low-formaldehyde technology, applied in the preparation of fiberboard, modified urea-formaldehyde resin, and the field of preparation, can solve the problems of low bonding strength, secondary pollution of melamine, etc., and achieve the effect of improving uniformity

Inactive Publication Date: 2015-08-19
王良源
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is that the bonding strength of the current modified urea-formaldehyde resin is low, and the addition of melamine is prone to secondary pollution

Method used

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  • Modified urea-formaldehyde resin with low content of formaldehyde, and preparation method and application thereof
  • Modified urea-formaldehyde resin with low content of formaldehyde, and preparation method and application thereof
  • Modified urea-formaldehyde resin with low content of formaldehyde, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Add 10 parts by weight of urea-formaldehyde resin and 6.5 parts by weight of propyl benzoate into a stirring tank, and mix at 50-70° C. to obtain modified urea-formaldehyde resin A.

[0050] Add the above-mentioned modified urea-formaldehyde resin A to 125 parts by weight of the fiber slurry and mix evenly, and dry the mixture at 50-70°C until the water content is 15wt%, to obtain a mixture. The mixture was pre-pressed at 4-5MPa for 30s to form a blank, and the blank was isostatically pressed at 8MPa and 70°C for 1min to form a slab. Hot press the slab, the hot pressing conditions are: temperature 110-120°C; rise to 13.5-19MPa within 20-30s, hold pressure for 60-120s; decompress to 3.5-5.5MPa within 10-15s, hold Press for 65-135s; then rise to 6-8.5MPa within 10-15s, hold the pressure for 50-75s; finally depressurize uniformly to 0MPa within 30-45s. The hot-pressed sheet was cooled to room temperature, tempered and sanded to obtain a fiberboard A with a thickness of 25...

Embodiment 2

[0052] Add 20 parts by weight of urea-formaldehyde resin and 11 parts by weight of propyl benzoate into a stirring tank, and mix at 50-70° C. to obtain modified urea-formaldehyde resin B.

[0053] The modified urea-formaldehyde resin B was added to 167 parts by weight of the fiber slurry for mixing, and the mixture was dried at 60-70° C. until the water content was 10 wt % to obtain a mixture. The mixture was pre-pressed at 4-5MPa for 40s to form a blank, and the blank was isostatically pressed at 7MPa and 70°C for 50s to form a slab. Hot press the slab, the hot pressing conditions are: temperature 110-120°C; rise to 13.5-19MPa within 20-30s, hold pressure for 60-120s; decompress to 3.5-5.5MPa within 10-15s, hold Press for 65-135s; then rise to 6-8.5MPa within 10-15s, hold the pressure for 50-75s; finally depressurize uniformly to 0MPa within 30-45s. The hot-pressed sheet was cooled to room temperature, tempered and sanded to obtain a fiberboard B with a thickness of 25 mm. ...

Embodiment 3

[0055] Heat 100 parts by weight of formaldehyde to 35-40°C, adjust the pH value to 7.0-8.0 with 20-25 wt% sodium hydroxide solution, add 33-35 parts by weight of urea and 0.02-0.03 parts by weight of diatomaceous earth, and raise the temperature to 88 React at -90°C for 30-40min; use 20-25wt% sodium hydroxide solution to adjust the pH value of the above product to 6.5-7.5, add 17-19 parts by weight of urea and 0.01-0.02 parts by weight of diatomaceous earth, at 88-92°C The reaction is terminated when the mixture is dropped into 70-75°C water and becomes white mist; adjust the pH value of the above product to 7.5-7.8 with 25-30wt% sodium hydroxide solution, and when the temperature drops to 75-80°C, add 15- 17 parts by weight of urea and 0.02-0.03 parts by weight of diatomaceous earth were reacted for 20 minutes, and the filtrate was filtered; then 8-10 parts by weight of urea and 0.03-0.04 parts by weight of diatomaceous earth were added to the obtained filtrate, and the temper...

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Abstract

The invention belongs to the technical field of adhesives, and relates to a modified urea-formaldehyde resin with a low content of formaldehyde. The modified urea-formaldehyde resin with a low content of formaldehyde comprises urea-formaldehyde resin and propyl benzoate. The invention also relates to a preparation method of the modified urea-formaldehyde resin, and a use of the modified urea-formaldehyde resin in production of fiberboards. The modified urea-formaldehyde resin can be used in the fields of building, decoration and industrial manufacturing, and can be used in bonding sheets, ceramics and plastics as an adhesive.

Description

technical field [0001] The invention belongs to the technical field of adhesives, and in particular relates to a modified urea-formaldehyde resin with low formaldehyde content, a preparation method and its application in fiberboard preparation. Background technique [0002] Formaldehyde is a recognized carcinogen. Scientific research at home and abroad has confirmed that formaldehyde can cause cell apoptosis by regulating DNA expression, cause oxidative damage to biological macromolecules (protein, DNA), and cause cell canceration. [0003] At present, most of the wood-based panels produced in China have residual free formaldehyde. The main sources of free formaldehyde are: i. The urea-formaldehyde resin commonly used in the manufacture of fiberboard uses formaldehyde as the main raw material, and there will still be unreacted free formaldehyde in the urea-formaldehyde resin; ii. Formaldehyde is released; iii. Hemicellulose in wood gradually decomposes to formaldehyde. Fre...

Claims

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Application Information

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IPC IPC(8): C08L61/24C08K5/101C08K3/34B27N3/04
Inventor 王良源
Owner 王良源
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