阅读说明：本技术 一种高密度纤维板的制备方法 (Preparation method of high-density fiberboard ) 是由 林桂成 陈元坤 潘光鹏 韦华龙 邓伟华 黄城 冯祖晓 于 2021-09-23 设计创作，主要内容包括：本发明提供一种高密度纤维板的制备方法,包括以下步骤：S1.将原木材料切片,调节木片含水率在30～40％；S2.将所述木片先进行初步软化,然后蒸煮,最后进行热磨；所述初步软化为采用纤维素酶和木聚糖酶酶解2～4d；所述蒸煮过程中,向蒸煮液中加入木片质量1～3％的碳酸钠和亚硫酸氢钠作为助剂；S3.将热磨后的纤维进行调施胶工序,然后进行干燥；S4.将干燥后的纤维进行板坯成型,然后再经过板坯预压,热压机热压,裁边,即得高密度纤维板的制备方法。该制备方法将木片先采用酶解进行初步软化,然后加助剂进行蒸煮,再热磨,可以提高纤维含量和改善纤维形态和物理性能,从而改善纤维板的性能。(The invention provides a preparation method of a high-density fiberboard, which comprises the following steps: s1, slicing a raw wood material, and adjusting the water content of wood chips to be 30-40%; s2, primarily softening the wood chips, then cooking, and finally carrying out hot grinding; performing preliminary softening by adopting cellulase and xylanase for enzymolysis for 2-4 d; in the cooking process, sodium carbonate and sodium bisulfite with the mass of 1-3% of wood chips are added into the cooking liquid as an auxiliary agent; s3, performing glue mixing and applying process on the hot-ground fibers, and then drying; and S4, forming the dried fiber into a board blank, then pre-pressing the board blank, hot-pressing the board blank by a hot press, and cutting edges to obtain the high-density fiberboard. The preparation method comprises the steps of firstly carrying out preliminary softening on wood chips by enzymolysis, then adding an auxiliary agent for stewing, and then carrying out hot grinding, so that the fiber content can be increased, the fiber form and the physical properties can be improved, and the performance of the fiberboard can be improved.)

1. The preparation method of the high-density fiberboard is characterized by comprising the following steps of:

s1, slicing a raw wood material, and adjusting the water content of wood chips to be 30-40%;

s2, primarily softening the wood chips, then cooking, and finally carrying out hot grinding;

performing preliminary softening by adopting cellulase and xylanase for enzymolysis for 2-4 d;

in the cooking process, sodium carbonate and sodium bisulfite with the mass of 1-3% of wood chips are added into the cooking liquid as an auxiliary agent;

s3, performing glue mixing and applying process on the hot-ground fibers, mixing and applying glue on the adhesive and the curing agent, and then drying;

and S4, forming the dried fiber into a board blank, then pre-pressing the board blank, hot-pressing the board blank by a hot press, and cutting edges to obtain the high-density fiberboard.

2. The method for preparing a high-density fiberboard of claim 1, wherein in the step S1, the raw material of the pine and the eucalyptus is selected in the slicing step in a ratio of 1: 1-3, and the high-density fiberboard is peeled and sliced.

3. The method for manufacturing high-density fiberboard of claim 1, wherein in the step S2, the cellulase dosage is 10 to 30IU/g and the xylanase dosage is 5 to 20IU/g based on the mass of the wood chips.

4. The method for preparing high-density fiberboard of claim 1, wherein in step S2, cellulase and xylanase are mixed, and then mixed with water at a mass ratio of 1: 80-200 to form an enzymatic hydrolysate, and the enzymatic hydrolysate is uniformly sprayed on wood chips for enzymolysis.

5. The method for preparing high-density fiberboard of claim 1, wherein in step S2, the cooking pressure is controlled to be 0.8 to 1.1MPa and the cooking time is controlled to be 2 to 5 min.

6. The method for preparing a high-density fiberboard of claim 1, wherein the mass ratio of the sodium carbonate to the sodium bisulfite is 1: 1-2.

7. The method for manufacturing high-density fiberboard of claim 1, wherein in the step S2, paraffin wax is added in an amount of 0.3 to 0.5% by weight of the wood chips during the hot grinding, and the pressure in the hot grinding chamber is controlled to be 0.8 to 0.9 bar.

8. The method for preparing the high-density fiberboard of claim 1, wherein in the step S3, the adhesive and the curing agent are mixed and sized, and the amount of the adhesive is 8-12%; the moisture content of the dried fiber is 10-12%.

9. The method for preparing high-density fiberboard of claim 1, wherein in step S3, the adhesive is urea-formaldehyde resin adhesive or melamine adhesive; the curing agent is ammonium chloride.

Technical Field

The invention relates to the technical field of fiber boards, in particular to a preparation method of a high-density fiber board.

Background

The high-density fiberboard is a board prepared by applying urea-formaldehyde resin or other synthetic resin to wood fiber or other plant fiber as raw material under the conditions of heating and pressurizing. The high-density fiberboard is compatible with all the advantages of medium density fiberboard by virtue of excellent physical properties, is widely applied to interior decoration of indoor and outdoor horizontal, office, high-grade furniture, sound and high-grade cars, and can also be used as a manufacturing material of antistatic floors, wall panels, security doors, wall panels, partition plates and the like of computer rooms. It is also a good material for packaging. In recent years, the wood floor is used for replacing high-grade hardwood to be directly processed into composite floors, reinforced floors and the like, is widely applied to interior decoration, and has good comment of users on smooth surfaces, solid texture and ultra-long service life. The high-density fiber board on the market at present has the defects of large pores, poor adsorbability and unstable chemical property.

The production process of the prior medium and high density fiberboard mainly comprises the procedures of raw wood chipping (or outsourcing wood chips), wood chip screening and cleaning, cooking, hot grinding, glue mixing and applying, drying, prepressing, hot pressing, sawing, cooling and the like. The most common raw wood at present is pine wood, when the pine wood material is insufficient, eucalyptus or other miscellaneous wood can be matched, but the pine wood content is required to be more than 50 percent generally, so the dependence on the pine wood is too high. The eucalyptus is listed as the lower raw material of the artificial fiberboard due to poor fiber shape and poor physical and mechanical properties of the fast-growing eucalyptus tip wood, is generally used only as a matching raw material and cannot be used as a main raw material, and when the proportion is too high, the problems of too low strength, fluffing, incompact structure, layer rising and the like of the fiberboard are caused by agreement, so that the research focus of the current stage is on how to improve the performance of the eucalyptus fibers and meet the requirements of the fiberboard manufacture.

Disclosure of Invention

The invention aims to solve the problems and provide a preparation method of a high-density fiberboard, which adopts a high proportion of eucalyptus as a raw material to obtain the high-density fiberboard with good performance.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation method of a high-density fiberboard comprises the following steps:

s1, slicing a raw wood material, and adjusting the water content of wood chips to be 30-40%.

S2, primarily softening the wood chips, then cooking, and finally carrying out hot grinding.

The preliminary softening is to carry out enzymolysis for 2-10 hours by adopting cellulase and xylanase.

In the cooking process, sodium carbonate and sodium bisulfite with the mass of 1-3% of wood chips are added into the cooking liquid as an auxiliary agent.

And S3, performing glue mixing and applying process on the hot-ground fibers, mixing and applying glue on the adhesive and the curing agent, and then drying.

And S4, forming the dried fiber into a board blank, then pre-pressing the board blank, hot-pressing the board blank by a hot press, and cutting edges to obtain the high-density fiberboard.

Preferably, in step S1, the cutting step is to peel and cut the pine and eucalyptus wood in a ratio of 1: 1-3.

Preferably, in the step S2, the dosage of the cellulase is 10-30 IU/g and the dosage of the xylanase is 5-20 IU/g based on the mass of the wood chips.

Preferably, in step S2, cellulase and xylanase are mixed, and then mixed with water at a mass ratio of 1: 80-200 to obtain an enzymatic hydrolysate, and the enzymatic hydrolysate is uniformly sprayed on the wood chips for enzymolysis.

Preferably, in step S2, the cooking pressure is controlled to be 0.8 to 1.1MPa, and the cooking time is controlled to be 2 to 5 min. The mass ratio of the sodium carbonate to the sodium bisulfite is 1: 1-2.

Preferably, in step S2, 0.3 to 0.5 wt% of paraffin wax is added during hot grinding, and the pressure in the hot grinding chamber is controlled to be 0.8 to 0.9 bar.

Preferably, in step S3, the adhesive and the curing agent are mixed and applied with the adhesive amount being 8-12%; the moisture content of the dried fiber is 10-12%.

Preferably, in step S3, the adhesive is urea-formaldehyde resin adhesive or melamine adhesive; the curing agent is ammonium chloride.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

1. according to the preparation method of the high-density fiberboard, wood chips are firstly subjected to preliminary softening by enzymolysis, then the wood chips are added with the auxiliary agent for cooking, and then the wood chips are subjected to hot grinding, so that the fiber content can be increased, the fiber form and the physical properties can be improved, and the performance of the fiberboard can be improved.

2. According to the preparation method of the high-density fiberboard, the xylanase and the cellulase are beneficial to softening of wood chips and scattering of fibers, the brittleness of the fibers is improved, and the separation degree of the fibers is increased. The spraying mode can save energy and reduce sewage discharge.

The cell wall of the wood chip is composed of a plurality of layers which are different in structure and chemical properties, when xylanase and cellulase act on the wood chip, the cohesion of the fiber is reduced, the fiber cell wall is separated, the internal tissue structure of the fiber cell wall becomes more loose, and the xylanase is also beneficial to promoting the release of fiber moisture, so that the fiber is easy to absorb water, swell and become soft. The wood chips are easy to split when being subsequently cooked and hot-milled, and the number of capillary pores of the wood chips is increased, so that the penetration of corresponding chemicals is facilitated, the efficiency is improved, and the use of additives is reduced.

During cooking, sodium carbonate and sodium bisulfite are used as auxiliary agents, and the sodium carbonate is added to remove lignin, impurities and the like of the wood chips, so that the content of cellulose is improved. The sulfite cooking liquor acts with lignin in the raw material, thereby realizing the separation of the components of the raw material and simultaneously increasing the permeation of the cooking liquor to the raw material. The permeation of the cooking liquor to the raw material depends on the diffusion function of the cooking liquor and the capillary action of the raw material, and the addition of the auxiliary agent also contributes to the forced permeation caused by the pressure rise in the cooking process. Thereby improving the problems of low utilization rate and poor performance of the eucalyptus fiber.

3. The preparation method of the high-density fiberboard adopts a large proportion of eucalyptus and pine to prepare the density fiberboard, has low cost and high resource utilization rate, has good economic benefit, and is easy to realize industrial production.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A preparation method of a high-density fiberboard comprises the following steps:

s1, slicing a raw wood material, and adjusting the water content of wood chips to be 30-40%. In the slicing procedure, pine and eucalyptus wood are used as raw materials, and peeling and slicing are carried out.

S2, primarily softening the wood chips, then cooking, and finally carrying out hot grinding.

The preliminary softening is carried out by enzymolysis for 3 hours by adopting cellulase and xylanase. The dosage of cellulase is 20IU/g and the dosage of xylanase is 10IU/g based on the mass of the wood chips. Mixing cellulase and xylanase, mixing the mixture with water in a mass ratio of 1: 80-200 to obtain an enzymolysis solution, and uniformly spraying the enzymolysis solution on wood chips for enzymolysis. The enzymolysis conditions are as follows: the temperature was 30 ℃.

In the cooking process, sodium carbonate and sodium bisulfite with the mass of 2 percent of wood chips are added into the cooking liquid as an auxiliary agent. And in the cooking process, the cooking pressure is controlled to be 0.9MPa, and the cooking time is controlled to be 3 min. The mass ratio of the sodium carbonate to the sodium bisulfite is 1: 1.

During hot grinding, 0.4% paraffin by weight of wood chips is added, and the pressure in a hot grinding chamber is controlled at 0.85 bar.

And S3, performing glue mixing and applying process on the hot-ground fibers, mixing and applying glue on the adhesive and the curing agent, and then drying.

Mixing an adhesive and a curing agent for sizing, wherein the adhesive dosage is 10%; the moisture content of the dried fiber was 11%. The adhesive is urea-formaldehyde resin adhesive or melamine adhesive; the curing agent is ammonium chloride.

The temperature of the drying inlet and the drying outlet is adjusted according to the requirement of production on the moisture content of the fiber, but the moisture content of the fiber is required to be stable. The inlet temperature is generally; 160 ℃ and an outlet temperature of 70 ℃. When the wood chips are drier, the outlet temperature is controlled to be lower; when the chips are relatively fresh, the exit temperature should be controlled somewhat higher.

And S4, forming the dried fiber into a board blank, then pre-pressing the board blank, hot-pressing the board blank by a hot press, and cutting edges to obtain the high-density fiberboard.

The slab prepressing process comprises the following steps: pre-pressing is carried out at normal temperature, and the maximum linear pressure is 190 kg/cm; the hot pressing process comprises the following steps: adopting a single-layer or multi-layer press, wherein the hot pressing temperature is 180 ℃, the hot pressing time is 0.2min/mm, and the maximum hot pressing pressure is 2.7 MPa; the post-processing technology comprises the following steps: cooling, cutting edges and sanding at normal temperature, wherein the cooling is carried out in a turning plate cooling device for 20 min.

Example 2

A preparation method of a high-density fiberboard comprises the following steps:

s1, slicing a raw wood material, and adjusting the water content of wood chips to be 30-40%. In the slicing procedure, pine and eucalyptus wood are used as raw materials, and peeling and slicing are carried out.

S2, primarily softening the wood chips, then cooking, and finally carrying out hot grinding.

The preliminary softening is carried out by enzymolysis for 3 hours by adopting cellulase and xylanase. The dosage of cellulase is 20IU/g and the dosage of xylanase is 10IU/g based on the mass of the wood chips. Mixing cellulase and xylanase, mixing the mixture with water in a mass ratio of 1: 80-200 to obtain an enzymolysis solution, and uniformly spraying the enzymolysis solution on wood chips for enzymolysis. The enzymolysis conditions are as follows: the temperature was 30 ℃.

In the cooking process, sodium carbonate and sodium bisulfite with the mass of 2 percent of wood chips are added into the cooking liquid as an auxiliary agent. And in the cooking process, the cooking pressure is controlled to be 0.9MPa, and the cooking time is controlled to be 3 min. The mass ratio of the sodium carbonate to the sodium bisulfite is 1: 1.

During hot grinding, 0.4% paraffin by weight of wood chips is added, and the pressure in a hot grinding chamber is controlled at 0.85 bar.

And S3, performing glue mixing and applying process on the hot-ground fibers, mixing and applying glue on the adhesive and the curing agent, and then drying.

Mixing an adhesive and a curing agent for sizing, wherein the adhesive dosage is 10%; the moisture content of the dried fiber was 11%. The adhesive is urea-formaldehyde resin adhesive or melamine adhesive; the curing agent is ammonium chloride.

The temperature of the drying inlet and the drying outlet is adjusted according to the requirement of production on the moisture content of the fiber, but the moisture content of the fiber is required to be stable. The inlet temperature is generally; 160 ℃ and an outlet temperature of 70 ℃. When the wood chips are drier, the outlet temperature is controlled to be lower; when the chips are relatively fresh, the exit temperature should be controlled somewhat higher.

And S4, forming the dried fiber into a board blank, then pre-pressing the board blank, hot-pressing the board blank by a hot press, and cutting edges to obtain the high-density fiberboard.

The slab prepressing process comprises the following steps: pre-pressing is carried out at normal temperature, and the maximum linear pressure is 190 kg/cm; the hot pressing process comprises the following steps: adopting a single-layer or multi-layer press, wherein the hot pressing temperature is 180 ℃, the hot pressing time is 0.2min/mm, and the maximum hot pressing pressure is 2.7 MPa; the post-processing technology comprises the following steps: cooling, cutting edges and sanding at normal temperature, wherein the cooling is carried out in a turning plate cooling device for 20 min.

Example 3

A preparation method of a high-density fiberboard comprises the following steps:

s1, slicing a raw wood material, and adjusting the water content of wood chips to be 30-40%. In the slicing procedure, pine and eucalyptus wood are used as raw materials, and peeling and slicing are carried out.

S2, primarily softening the wood chips, then cooking, and finally carrying out hot grinding.

The preliminary softening is carried out by enzymolysis for 3 hours by adopting cellulase and xylanase. The dosage of cellulase is 20IU/g and the dosage of xylanase is 10IU/g based on the mass of the wood chips. Mixing cellulase and xylanase, mixing the mixture with water in a mass ratio of 1: 80-200 to obtain an enzymolysis solution, and uniformly spraying the enzymolysis solution on wood chips for enzymolysis. The enzymolysis conditions are as follows: the temperature was 30 ℃.

In the cooking process, sodium carbonate and sodium bisulfite with the mass of 2 percent of wood chips are added into the cooking liquid as an auxiliary agent. And in the cooking process, the cooking pressure is controlled to be 0.9MPa, and the cooking time is controlled to be 3 min. The mass ratio of the sodium carbonate to the sodium bisulfite is 1: 1.

During hot grinding, 0.4% paraffin by weight of wood chips is added, and the pressure in a hot grinding chamber is controlled at 0.85 bar.

And S3, performing glue mixing and applying process on the hot-ground fibers, mixing and applying glue on the adhesive and the curing agent, and then drying.

Mixing an adhesive and a curing agent for sizing, wherein the adhesive dosage is 10%; the moisture content of the dried fiber was 11%. The adhesive is urea-formaldehyde resin adhesive or melamine adhesive; the curing agent is ammonium chloride.

The temperature of the drying inlet and the drying outlet is adjusted according to the requirement of production on the moisture content of the fiber, but the moisture content of the fiber is required to be stable. The inlet temperature is generally; 160 ℃ and an outlet temperature of 70 ℃. When the wood chips are drier, the outlet temperature is controlled to be lower; when the chips are relatively fresh, the exit temperature should be controlled somewhat higher.

And S4, forming the dried fiber into a board blank, then pre-pressing the board blank, hot-pressing the board blank by a hot press, and cutting edges to obtain the high-density fiberboard.

The slab prepressing process comprises the following steps: pre-pressing is carried out at normal temperature, and the maximum linear pressure is 190 kg/cm; the hot pressing process comprises the following steps: adopting a single-layer or multi-layer press, wherein the hot pressing temperature is 180 ℃, the hot pressing time is 0.2min/mm, and the maximum hot pressing pressure is 2.7 MPa; the post-processing technology comprises the following steps: cooling, cutting edges and sanding at normal temperature, wherein the cooling is carried out in a turning plate cooling device for 20 min.

Comparative example 1

Compared with the embodiment 2, the preparation method of the high-density fiberboard does not comprise a primary softening process and comprises direct cooking and hot grinding. The other steps are the same.

Comparative example 2

Compared with the embodiment 2, the preparation method of the high-density fiberboard only adds xylanase for enzymolysis in the primary softening process, the using amount is 20IU/g, and other steps are the same.

Comparative example 3

Compared with the embodiment 2, the preparation method of the high-density fiberboard only adds cellulase for enzymolysis in the primary softening process, the dosage is 20IU/g, and other steps are the same.

Comparative example 4

Compared with the embodiment 2, the preparation method of the high-density fiberboard only adds sodium carbonate as an auxiliary agent in the cooking process, the using amount of the sodium carbonate is 2 percent of the mass of the wood chips, and other steps are the same.

Comparative example 5

Compared with the embodiment 2, the preparation method of the high-density fiberboard only adds sodium bisulfite as an auxiliary agent in the cooking process, the using amount of the sodium bisulfite is 2 percent of the mass of the wood chips, and other steps are the same.

Fiberboards having a gauge of 1220mm x 2440mm, the thickness of which was 20mm, were prepared by the methods provided in examples 1-3 and comparative examples 1-5, respectively, and then the fiberboards were subjected to performance tests, and the results were recorded as follows:

wherein the static bending strength and the elastic modulus are measured according to the measuring method specified in GB/T11718-2009 at 6.8; the internal bond strength was measured by the internal bond strength measuring method specified in GB/T17657.

TABLE 1 results record

From the data of examples 1 to 3, it can be seen that the high-density fiberboard prepared by the preparation method of the present invention meets the national requirements by peeling and slicing the raw material of eucalyptus, which is the pine wood, in a ratio of 1: 1-3, but the raw material of eucalyptus, which is the pine wood, is preferably selected in a ratio of 1: 1-2 because the raw material of eucalyptus, which is the pine wood, is just up to the standard.

It can be seen from the comparative data of comparative examples 1-3 and example 2 that the performance of the high-secretin fiberboard is improved by using xylanase and cellulase for preliminary softening and then using sodium carbonate and sodium bisulfite as auxiliary agents during cooking.

And the xylanase and the cellulase have combined action, so that the softening of wood chips and the scattering of fibers are promoted, the brittleness of the fibers is improved, the separation degree of the fibers is increased, and the single action effect is slightly poor. The sodium carbonate and the sodium bisulfite are used as auxiliary agents, lignin, impurities and the like of the wood chips can be removed, and meanwhile, the permeation of the cooking liquor to the raw materials is increased, so that the content of cellulose is increased, and the single action effect is slightly poor.

The above description is intended to describe in detail the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the claims of the present invention, and all equivalent changes and modifications made within the technical spirit of the present invention should fall within the scope of the claims of the present invention.