CN100558520C - Preparation method of bamboo fiberboard with modified soybean protein adhesive - Google Patents

Abstract

The invention discloses a method for preparing a modified soybean protein adhesive for bamboo fiberboard, which comprises the following steps: 1) Glue adjustment: add 1 part of polyoxypropylene glyceryl ether to 88 parts of modifying reagent solution, and then gradually add 10 parts of soybean Isolate the protein and stir for 2-3 hours; then add 1 part of potassium sorbate as a preservative and stir evenly; 2) Sizing: mix the bamboo fiber and modified soybean protein adhesive evenly; 3) Hot pressing: adjust the result of step 2) The moisture content of bamboo fiber is 24-27% to obtain a slab; then the slab is hot-pressed to obtain a bamboo fiber board. Using the method of the invention can realize the non-formaldehyde production of the fiber board, thereby improving the quality grade of the fiber board product.

Description

Preparation method of bamboo fiberboard with modified soybean protein adhesive

technical field

The invention relates to a preparation process of a bamboo fiberboard with a modified soybean protein adhesive, in particular to a preparation process of an environment-friendly medium density fiberboard, which belongs to the field of wood-based panels.

Background technique

Fiberboard has uniform structure, moderate density, smooth surface and good processing performance, so it is widely used in furniture manufacturing and construction. At present, the raw materials widely used in the preparation of fiberboard are wood fiber and urea-formaldehyde resin. However, with the excessive cutting of forest resources, how to ensure sufficient supply of raw materials has become an important social and economic issue. In addition, urea-formaldehyde resin is derived from non-renewable petrochemical resources, and it is easy to release free formaldehyde in a hot and humid environment, which seriously pollutes the environment and endangers human health. With the continuous rise of crude oil prices and people's increasing concern about their own and environmental safety, this problem has become more serious. The research on environment-friendly wood-based panels based on renewable resources has been paid more and more attention by countries.

China is rich in bamboo resources. There are more than 400 species of bamboo in 40 genera, covering an area of 8 million hm ² , accounting for 40% of the world's bamboo forest area. It is distributed in other provinces and autonomous regions except Xinjiang, Inner Mongolia, Heilongjiang and Jilin. There are thousands of bamboo processing factories in my country, and the annual harvesting volume of bamboo forests reaches 400 million plants, 12 million tons. In the bamboo processing industry, a large amount of bamboo fiber residues are discarded and not fully utilized. Bamboo grows fast and has high output. Compared with wood, bamboo has the characteristics of high strength and good toughness. It is an ideal raw material for fiberboard. During the preparation of fiberboard, due to uneven sizing, it is easy to cause fiber agglomeration and felting, which directly affects the performance of the board. At present, the research on the production process of bamboo fiberboard for soybean protein adhesive is almost blank.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing bamboo fiberboard with a modified soybean protein adhesive, which can realize the non-formaldehyde production of the fiberboard, thereby improving the quality grade of the fiberboard product.

In order to solve the problems of the technologies described above, the invention provides a method for preparing a bamboo fiberboard of a modified soybean protein adhesive, comprising the following steps:

1), glue adjustment:

Add 1 part of polyoxypropylene glyceryl ether as a defoamer to 88 parts of modifying reagent solution, then gradually add 10 parts of soybean protein isolate, and stir for 2 to 3 hours; then add 1 part of potassium sorbate as a preservative, and stir evenly To obtain the modified soybean protein adhesive; the above parts are parts by weight;

2), sizing:

The bamboo fiber and the modified soybean protein adhesive are evenly mixed; the solid content of the modified soybean protein adhesive/the weight sum of the dry matter of the bamboo fiber and the solid content of the modified soybean protein adhesive=11～16:100;

3), hot pressing:

Adjustment step 2) The water content of the product is 24-27%, to obtain a slab; then the slab is hot-pressed to obtain a bamboo fiber board.

As the improvement of the bamboo fiberboard preparation method of the modified soybean protein adhesive of the present invention: step 1) in the modification reagent solution, the sodium hydroxide solution that the weight concentration is 0.2% or the sodium lauryl sulfate that the weight concentration is 1% solution.

As a further improvement of the bamboo fiberboard preparation method of the modified soybean protein adhesive of the present invention: Step 2) is: use compressed air to make the bamboo fibers in the drum in a suspended state, and transport the modified soybean protein adhesive to the drum for installation Spray the modified soybean protein adhesive evenly on the bamboo fiber in the form of mist; at the same time, rotate the drum to further uniformly stir the modified soybean protein adhesive and the bamboo fiber.

Further improvement of the preparation method of the bamboo fiber board as the modified soybean protein adhesive of the present invention: the hot pressing process parameters in step 3) are: temperature 170-180° C., pressure 5-7 MPa, time 47-70 s/mm.

Further improvement of the bamboo fiber board preparation method as the modified soybean protein adhesive of the present invention: the length of the bamboo fiber in step 2) is 10-20mm.

As a further improvement of the bamboo fiberboard preparation method of the modified soybean protein adhesive of the present invention: the weight sum of the solid content of the modified soybean protein adhesive/the dry matter of the bamboo fiber and the solid content of the modified soybean protein adhesive=13:100.

Further improvement of the bamboo fiber board preparation method as the modified soybean protein adhesive of the present invention: adjusting the moisture content to 25%.

In the preparation method of the present invention, in step 1), the sodium hydroxide solution with a weight concentration of 0.2% is formed by mixing 0.2 parts by weight of sodium hydroxide with 99.8 parts by weight of water; The sodium lauryl sulfate solution is formed by mixing 1 part by weight of sodium lauryl sulfate and 99 parts by weight of water. In step 2), the sizing method used is a sizing process of mixing and stirring suspended fibers and mist glue; the solid content of the modified soybean protein adhesive represents: the content of soybean protein isolate in the modified soybean protein adhesive. Step 3) The moisture content can be adjusted through the moisture regulating equipment, and the time of 47-70 s/mm means that it takes 47-75 s to press the bamboo fiberboard of every mm thickness.

The bamboo fiber board prepared by adopting the modified soybean protein adhesive does not release formaldehyde, is easily biodegradable after being discarded, and is an environment-friendly board.

In summary, the preparation method of the present invention has the following beneficial effects:

1. Bamboo fiber is used as raw material, so it has the advantages of wide source of raw materials and can reduce production costs; the discarded bamboo fiber board is easy to biodegrade and can be recycled;

2. Due to the uniform sizing, the bamboo fiber board obtained has excellent performance;

3. The modified soybean protein adhesive is used to ensure that the obtained bamboo fiberboard has no formaldehyde release, which meets the requirements of environmental protection and is an environmentally friendly product;

4. The preparation process is simple, easy for industrialization, and can promote the value-added utilization of soybean protein isolate and the resource utilization of bamboo industry processing residues.

Detailed ways

Below in conjunction with example the present invention is described in further detail.

Embodiment 1, a kind of bamboo fiber board preparation method of modified soybean protein adhesive, carry out following steps successively:

1), glue adjustment:

First add 0.2g sodium hydroxide in every 99.8g of water to prepare a concentration of 0.2% sodium hydroxide solution; then add 1kg polyoxypropylene glyceryl ether as a defoamer in 88kg of the above sodium hydroxide solution, and then use Add 10kg of soybean protein isolate while stirring at a speed of 20kg/h; then stir with an electric mixer at room temperature for 2 hours to dissolve all the soybean protein isolate, and finally add 1kg of potassium sorbate as a preservative, and stir well to obtain 100kg Modified soy protein adhesive.

2), sizing:

Weigh 74.3kg of bamboo fiber with a length of 10-20mm (the amount of dry matter is 66.9kg), put it into the rubber mixing drum, suspend the bamboo fiber in the drum with compressed air, and mix 100kg of modified soybean protein with a rubber pump The adhesive is transported to the sprayer installed in the drum, so that the modified soybean protein adhesive is evenly sprayed on the bamboo fiber in the form of mist; the modified soybean protein adhesive and the bamboo fiber are further uniformly mixed by the rotation of the drum; that is, the modified soybean protein adhesive The sum of the weight of the dry matter of the solid content/bamboo fiber and the solid content of the modified soybean protein adhesive=10/(66.9+10)=13%.

3), hot pressing: first adjust the moisture content of the product obtained in step 2) to 25% through a moisture adjustment device to obtain a slab; then pave the slab for hot pressing and curing molding, and set the thickness of the fiberboard to 9mm and the density to 0.67g /cm ³ , the controlled hot-pressing process conditions are: the hot-pressing temperature is 180°C, the pressure is 7MPa, and the time is 9min; the bamboo fiber board is obtained.

Embodiment 2, a kind of bamboo fiber board preparation method of modified soybean protein adhesive, carry out following steps successively:

1), glue adjustment:

With embodiment 1, obtain 100kg modified soybean protein adhesive.

2), sizing:

With embodiment 2.

3), hot pressing: first adjust the moisture content of the product obtained in step 2) to 25% through a moisture adjustment device to obtain a slab; then pave the slab for hot pressing and curing molding, and set the thickness of the fiberboard to 10mm and the density to 0.60g /cm ³ , the controlled hot-pressing process conditions are: the hot-pressing temperature is 170°C, the pressure is 7MPa, and the time is 8min; the bamboo fiber board is obtained.

Embodiment 3, a kind of bamboo fiberboard preparation method of modified soybean protein adhesive, carry out following steps successively:

1), glue adjustment:

First add the ratio of 1g sodium lauryl sulfate in every 99g water and be mixed with the sodium lauryl sulfate solution that concentration is 1%; Then add 1kg polyoxypropylene glyceryl ether in 88kg above-mentioned sodium lauryl sulfate solution as Defoamer, then gradually add 10kg of soybean protein isolate, stir with an electric mixer at room temperature for 3 hours to dissolve all the soybean protein isolate; finally add 1kg of potassium sorbate as a preservative, and mix well to obtain 100kg of modified soybean protein adhesive .

2), sizing:

Weigh 74.3kg of bamboo fiber with a length of 10-20mm (the amount of dry matter is 66.9kg), put it into the rubber mixing drum, suspend the bamboo fiber in the drum with compressed air, and mix 100kg of modified soybean protein with a rubber pump The adhesive is transported to the sprayer installed in the drum, so that the modified soybean protein adhesive is evenly sprayed on the bamboo fiber in the form of mist; the modified soybean protein adhesive and the bamboo fiber are further uniformly mixed by the rotation of the drum, that is, the modified soybean protein adhesive The sum of the weight of the dry matter of the solid content/bamboo fiber and the solid content of the modified soybean protein adhesive=10/(66.9+10)=13%.

3), hot pressing: first adjust the moisture content of the product obtained in step 2) to 25% through a moisture adjustment device to obtain a slab; then pave the slab for hot pressing and curing molding, and set the thickness of the fiberboard to 9mm and the density to 0.66g /cm ³ , the controlled hot-pressing process conditions are: the hot-pressing temperature is 170°C, the pressure is 6MPa, and the time is 8min; the bamboo fiber board is obtained.

Embodiment 4, a kind of bamboo fiber board preparation method of modified soybean protein adhesive, carries out following steps successively:

1), glue adjustment:

With embodiment 3, obtain 100kg modified soybean protein adhesive.

2), sizing:

Weigh 63kg of bamboo fiber with a length of 10-20mm (the amount of dry matter is 56.7kg), put it into the rubber mixing drum, suspend the bamboo fiber in the drum with compressed air, and put 100kg of modified soybean protein adhesive through a rubber pump It is transported to the sprayer installed in the drum, so that the modified soybean protein adhesive is evenly sprayed on the bamboo fiber in the form of mist; the modified soybean protein adhesive and the bamboo fiber are further uniformly mixed through the rotation of the drum, that is, the solidification of the modified soybean protein adhesive The weight sum of the dry matter of content/bamboo fiber and the solid content of modified soybean protein adhesive=10/(56.7+10)=15%.

3), hot pressing: first adjust the moisture content of the product obtained in step 2) to 27% through a moisture regulating device to obtain a slab; then pave the slab for hot pressing and curing molding, and set the thickness of the fiberboard to 9mm and the density to 0.58g /cm ³ , the controlled hot-pressing process conditions are: the hot-pressing temperature is 180°C, the pressure is 6MPa, and the time is 9min; the bamboo fiber board is obtained.

According to the method stipulated in GB/T 17657-1999, the physical and mechanical properties of medium density bamboo fiberboard were tested. The test results are shown in Table 1. The indicators such as static bending strength, internal bonding strength and water absorption thickness expansion rate all reached the first class of fiberboard. product national standards.

Table 1 Physical and mechanical properties test results of fiberboard

Density (g/cm³) Static Bending Strength (MPa) Internal bonding strength (MPa) Thickness expansion rate (%) Free formaldehyde emission (mg/100g) Example 1 0.67 28.9 0.63 6.5 0 Example 2 0.60 26.8 0.60 7.5 0 Example 3 0.66 25.3 0.65 8.2 0 Example 4 0.58 23.8 0.60 8.5 0 National standard for first-class fiberboard 0.45～0.88 ≥22.0 ≥0.55 ≤12.0 ≤40

Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (7)

1, a kind of bamboo fiberboard preparation method of modified soybean protein adhesive, it is characterized in that comprising the following steps: 1), glue adjustment: Add 1 part of polyoxypropylene glyceryl ether as a defoamer to 88 parts of modifying reagent solution, then gradually add 10 parts of soybean protein isolate, and stir for 2 to 3 hours; then add 1 part of potassium sorbate as a preservative, and stir evenly To obtain the modified soybean protein adhesive; the above parts are parts by weight; 2), sizing: The bamboo fiber and the modified soybean protein adhesive are evenly mixed; the solid content of the modified soybean protein adhesive/the weight sum of the dry matter of the bamboo fiber and the solid content of the modified soybean protein adhesive=11～16:100; 3), hot pressing: Adjustment step 2) The water content of the product is 24-27%, to obtain a slab; then the slab is hot-pressed to obtain a bamboo fiber board. 2, according to the described method for preparing the bamboo fiber board of modified soybean protein adhesive of claim 1, it is characterized in that: in described step 1), the modification reagent solution is the sodium hydroxide solution that weight concentration is 0.2% or is that weight concentration is 1 % sodium lauryl sulfate solution. 3. The method for preparing bamboo fiberboard with modified soybean protein adhesive according to claim 2, characterized in that: said step 2) is: using compressed air to make the bamboo fiber in the drum be in a suspended state, and the modified soybean The protein adhesive is transported to the sprayer installed in the drum, so that the modified soybean protein adhesive is evenly sprayed on the bamboo fiber in the form of mist; at the same time, the drum is rotated to further uniformly stir the modified soybean protein adhesive and the bamboo fiber. 4. The method for preparing bamboo fiberboard with modified soybean protein adhesive according to claim 3, characterized in that: the hot pressing process parameters in step 3) are: temperature 170-180°C, pressure 5-7MPa, time 47-70s /mm. 5. The method for preparing bamboo fiber board with modified soybean protein adhesive according to claim 4, characterized in that: the length of the bamboo fiber in the step 2) is 10-20 mm. 6. The method for preparing bamboo fiberboard with modified soybean protein adhesive according to claim 5, characterized in that: the weight sum of the solid content of modified soybean protein adhesive/the dry matter of bamboo fiber and the solid content of modified soybean protein adhesive =13:100. 7. The method for preparing bamboo fiber board with modified soybean protein adhesive according to claim 6, characterized in that the water content is adjusted to 25%.