Low-formaldehyde-content medium-density fiberboard

Abstract

The invention belongs to the technical field of fiberboards, and relates to a low-formaldehyde-content medium-density fiberboard. The fiberboard comprises fibers, adhesive and propyl benzoate and is suitable for the fields of building, decorating, industrial manufacturing and the like.

Description

technical field

[0001] The invention belongs to the technical field of fiberboards, in particular to a medium density fiberboard with low formaldehyde content. 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 domestically produced fiberboards 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. Free formaldehyde remaining in fiberboard will endanger human health, so it is necessary t...

Examples

Embodiment 1

[0059] 125 parts by weight of fiber slurry, 10 parts by weight of urea-formaldehyde resin, and 6.5 parts by weight of propyl benzoate are uniformly mixed in a stirring tank, and the mixture is dried at 50-70°C until the water content is 15 wt%, 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. The slab is hot-pressed, and the hot-pressing conditions are: temperature 150-160°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 plate was cooled to normal temperature, tempered and sanded to obtain medium density fiberboard A with a thickness of 25 mm.

[0060] It has been determined that the composition of the medium density fiberboard A is 85wt% fiber, 10w...

Embodiment 2

[0062] 167 parts by weight of fiber slurry, 20 parts by weight of urea-formaldehyde resin, and 11 parts by weight of propyl benzoate are uniformly mixed in a stirring tank, and the mixture is dried at 60-70°C until the water content is 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. The slab is hot-pressed, and the hot-pressing conditions are: temperature 150-160°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 plate was cooled to normal temperature, tempered and sanded to obtain medium density fiberboard B with a thickness of 25 mm.

[0063] It has been determined that the composition of the medium density fiberboard B is 76wt% fiber, 15wt%...

Embodiment 3

[0065] 140 parts by weight of fiber slurry, 15 parts by weight of modified urea-formaldehyde resin, and 4.5 parts by weight of propyl benzoate were uniformly mixed in a stirring tank, and the mixture was dried at 80° C. until the moisture content was 10 wt % to obtain a mixture. The mixture is pre-pressed at 4-5MPa for 1min to form a blank, and the blank is isostatically pressed at 7-8MPa and 60-70°C for 50s to form a slab. The slab is hot-pressed, and the hot-pressing conditions are: temperature 150-160°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 plate was cooled to normal temperature, tempered and sanded to obtain a medium density fiberboard C with a thickness of 25 mm.

[0066] It has been determined that the composition of the medium density fiberboard C ...

technical field

[0001] The invention belongs to the technical field of fiberboards, in particular to a medium density fiberboard with low formaldehyde content. 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 domestically produced fiberboards 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. Free formaldehyde remaining in fiberboard will endanger human health, so it is necessary t...

Examples

Embodiment 1

[0059] 125 parts by weight of fiber slurry, 10 parts by weight of urea-formaldehyde resin, and 6.5 parts by weight of propyl benzoate are uniformly mixed in a stirring tank, and the mixture is dried at 50-70°C until the water content is 15 wt%, 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. The slab is hot-pressed, and the hot-pressing conditions are: temperature 150-160°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 plate was cooled to normal temperature, tempered and sanded to obtain medium density fiberboard A with a thickness of 25 mm.

[0060] It has been determined that the composition of the medium density fiberboard A is 85wt% fiber, 10w...

Embodiment 2

[0062] 167 parts by weight of fiber slurry, 20 parts by weight of urea-formaldehyde resin, and 11 parts by weight of propyl benzoate are uniformly mixed in a stirring tank, and the mixture is dried at 60-70°C until the water content is 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. The slab is hot-pressed, and the hot-pressing conditions are: temperature 150-160°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 plate was cooled to normal temperature, tempered and sanded to obtain medium density fiberboard B with a thickness of 25 mm.

[0063] It has been determined that the composition of the medium density fiberboard B is 76wt% fiber, 15wt%...

Embodiment 3

[0065] 140 parts by weight of fiber slurry, 15 parts by weight of modified urea-formaldehyde resin, and 4.5 parts by weight of propyl benzoate were uniformly mixed in a stirring tank, and the mixture was dried at 80° C. until the moisture content was 10 wt % to obtain a mixture. The mixture is pre-pressed at 4-5MPa for 1min to form a blank, and the blank is isostatically pressed at 7-8MPa and 60-70°C for 50s to form a slab. The slab is hot-pressed, and the hot-pressing conditions are: temperature 150-160°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 plate was cooled to normal temperature, tempered and sanded to obtain a medium density fiberboard C with a thickness of 25 mm.

[0066] It has been determined that the composition of the medium density fiberboard C ...

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