Manufacturing method of homogeneous bamboo-wood composite plywood

Abstract

The invention belongs to the technical field of artificial board preparation, and particularly relates to a manufacturing method of homogeneous bamboo-wood composite plywood. In order to solve the problem that in the prior art, a technical method which is good in effect and convenient to operate is lacked for manufacturing the homogeneous bamboo-wood composite plywood, the manufacturing method of the homogeneous bamboo-wood composite plywood comprises the steps that a woven bamboo curtain is soaked in soaking phenolic glue and then dried; coating the surface of the wood veneer with a coating adhesive containing phenolic resin glue and an expansion auxiliary agent, and combining the impregnated bamboo wood and the glued wood veneer to obtain a core layer; and the surface layer, the core layer and the bottom layer are combined with one another and subjected to preheating treatment, prepressing and hot pressing under the heating condition, and the bamboo-wood composite plywood is obtained. According to the bamboo-wood composite plywood, the surface of the wood veneer is coated with the adhesive, and the expansion additive is added into the coated adhesive, so that holes and gaps in a board blank are effectively filled with the adhesive after the adhesive is heated and expanded in the preheating treatment and hot pressing processes, and the uniformity of the mechanical strength and the use durability of the bamboo-wood composite plywood are effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial board preparation, and in particular relates to a method for manufacturing a homogeneous bamboo-wood composite plywood. Background Art

[0002] Bamboo has become a green material with great potential to replace wood due to its excellent performance, eco-friendliness and processability, and is suitable for a variety of traditional and modern application scenarios. At present, most of the bamboo used to make bamboo-wood composite plywood is in the form of woven bamboo curtains, which are made by weaving radial bamboo strips through cotton thread. Compared with processing forms such as bamboo mats and bamboo shavings, bamboo curtain processing can meet large-scale production more quickly and ensure a stable supply of raw materials. Compared with bamboo shavings, bamboo curtains retain the natural form of bamboo, and the structural strength of the finished product is higher than that of bamboo shavings. However, since bamboo curtains are made of radial bamboo strips woven through cotton thread, there are wide gaps between bamboo strips, especially when multiple bamboo curtains are used in a bamboo-wood composite plywood, even bamboo-wood composite plywood manufactured under high temperature and high pressure conditions will have many uneven holes. These holes will cause local quality defects and uneven performance of the plywood, greatly reducing the service life of the plywood, and will also affect the aesthetics of the edges of the product.

[0003] In response to this problem, people have also conducted exploration and research in long-term production and life practices. For example, in the Chinese invention patent application entitled "Special Filling Powder for Plywood" with application number "201110246542.3", a special filling powder for plywood is provided. Heavy calcium carbonate, pregelatinized starch, grain powder and wood powder are mixed with resin glue in different proportions. The obtained adhesive has good dispersibility and fluidity. During the hot pressing process, it can better penetrate into the gaps in the wood tissue and play a filling and strengthening role. However, the filling effect of this filling powder depends on the flow of the glue liquid during hot pressing. Due to the effect of the hot pressing temperature, the glue liquid solidifies quickly, the filling effect is general, and the amount of glue applied to the veneer needs to be increased to achieve the effect. In the Chinese invention patent entitled "Method for producing homogeneous container bottom plate" with application number "201210398982.5", medium and low density wood veneers are used for multiple times of dipping and then composited with bamboo veneers to produce a homogeneous bamboo-wood composite bottom plate with uniform texture and high strength. However, this method requires multiple dippings to make the density of bamboo veneer close to that of wood veneer, and it is also necessary to ensure that the amount of dipping is uniform each time. The holes on the edge of the finished product are improved, but the production efficiency is reduced and the production cost is increased. In addition, the holes and gaps on the edge of the finished board after the sawing and milling of plywood are mostly filled with inorganic putty for decoration. However, the strength and elasticity of inorganic putty are poor, the filling effect is poor, and it is easy to fall off. In the Chinese invention patent application entitled "A Plywood Putty and Its Preparation Method" with application number "201611171640.4", a putty for filling holes, gaps, debonding and other defects that appear in plywood after hot pressing is disclosed; in the Chinese invention patent application entitled "A Plywood Adaptive Filling Filler and Its Preparation Method and Application" with application number "202311109756.5", a filling filler is prepared by adding wood powder and stone powder to a flexible foaming adhesive to fill the surface defects of plywood. The above filling putty only covers the holes and gaps on the surface of the plywood, and the holes inside it still exist. The uniformity of the strength of the board cannot be guaranteed, and it causes local damage during use, and its durability is inconsistent.

[0004] In summary, the prior art lacks a technical method with good effect and convenient operation to produce homogeneous bamboo-wood composite plywood. Summary of the invention

[0005] The object of the present invention is to provide a method for manufacturing a homogeneous bamboo-wood composite plywood in view of the above problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for manufacturing a homogeneous bamboo-wood composite plywood comprises the following steps:

[0008] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0009] Step 2: applying a coating adhesive comprising a phenolic resin glue and an expansion aid to the surface of the wood veneer to obtain a glue-coated wood veneer;

[0010] Step 3: Compounding the glue-impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2 to obtain a core layer;

[0011] Step 4: Use 3-5 pieces of wood veneer symmetrically to form the surface layer and the bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack;

[0012] Step 5: preheat the board stack obtained in step 4 under heating conditions, obtain a slab after pre-pressing, and then hot-press the slab to obtain a bamboo-wood composite plywood, and then obtain a finished plywood after sawing and trimming.

[0013] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, the coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 10-15 parts of expansion aid.

[0014] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, the expansion aid includes 0.5-2 parts by weight of sodium bicarbonate, 0.2-0.5 parts by weight of alum, 0.5-0.8 parts by weight of sodium hydroxide, 1-2 parts by weight of dioctyl phthalate, 5-10 parts by weight of flour and 3-6 parts by weight of calcium carbonate.

[0015] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, the viscosity of the coating adhesive is 2000cps-3500cps.

[0016] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, in the step 2, the adhesive applied to the surface of the wood veneer is 350-450 g / m 2 .

[0017] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, the core layer in step three is composed of a glue-coated wooden veneer and a glue-impregnated bamboo material alternately stacked or a glue-coated wooden veneer and two glue-impregnated bamboo materials alternately stacked.

[0018] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, the total number of core layers is 6-15 layers.

[0019] In the above-mentioned method for manufacturing homogeneous bamboo-wood composite plywood, the thickness of the board stack assembly in step 4 is 25-45 mm.

[0020] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, the temperature of the preheating treatment in step 5 is 30-45° C., and the treatment time is 25-35 minutes.

[0021] In the above-mentioned method for manufacturing a homogeneous bamboo-wood composite plywood, in step 5, the hot pressing temperature of the slab is 130-150° C., the pressure is 3.0-5.0 MPa, and the hot pressing time is calculated based on the thickness of the slab stack of 0.8-1.2 min / mm.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] 1. The present invention coats adhesive on the surface of the wood veneer, and adds an expansion aid to the adhesive, so that the adhesive expands after heating during preheating and hot pressing to effectively fill the holes and gaps in the slab, and finally achieves uniform distribution of density, strength and thickness of the bamboo-wood composite plywood, improves the uniformity of mechanical strength and durability of the bamboo-wood composite plywood, and is convenient and easy to operate in adjusting the glue.

[0024] 2. The internal expansion filling method adopted by the present invention effectively compensates for the defects of too many holes and gaps on the edges of the finished board, improves the aesthetics of the board, and improves production efficiency and reduces labor costs compared to the method of using putty to scrape and fill the holes and gaps on the edges of plywood in the prior art. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific implementation methods.

[0026] Example 1

[0027] This embodiment provides a method for manufacturing a homogeneous bamboo-wood composite plywood, comprising the following steps:

[0028] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0029] Step 2: Apply the coating adhesive containing phenolic resin glue and expansion aid to the surface of the wood veneer to obtain the coated wood veneer. The viscosity of the adhesive is adjusted to 3000cps, and the amount of the adhesive applied to the surface of the wood veneer is 400g / m 2 ;

[0030] Step 3: Combine the impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2, in a combination method of alternately stacking one glue-coated wood veneer and two impregnated bamboo materials, for a total of 15 layers, to obtain a core layer;

[0031] Step 4: symmetrically use 3 wooden veneers to form a surface layer and a bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack, and the thickness of the board stack is 41mm;

[0032] Step 5: preheat the board stack obtained in step 4 under heating conditions, the preheating temperature is 40° C., the treatment time is 25 min, and a slab is obtained after pre-pressing. The slab is then hot-pressed at a temperature of 140° C., a pressure of 4.0 MPa, and a hot-pressing time of 49.2 min to obtain a bamboo-wood composite plywood, which is then sawed to the edges to obtain a finished plywood.

[0033] The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 10 parts of expansion aid; the expansion aid includes 0.5 parts of sodium bicarbonate, 0.2 parts of alum, 0.5 parts of sodium hydroxide, 1 part of dioctyl phthalate, 8 parts of flour and 3 parts of calcium carbonate in mass parts respectively.

[0034] Example 2

[0035] This embodiment provides a method for manufacturing a homogeneous bamboo-wood composite plywood, comprising the following steps:

[0036] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0037] Step 2: Apply the coating adhesive containing phenolic resin glue and expansion aid to the surface of the wood veneer to obtain the coated wood veneer. The viscosity of the adhesive is controlled at 3000cps, and the amount of the adhesive applied to the surface of the wood veneer is 300g / m 2 ;

[0038] Step 3: Combine the impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2, in a combination method of alternately stacking one glue-coated wood veneer and two impregnated bamboo materials, for a total of 15 layers, to obtain a core layer;

[0039] Step 4: symmetrically use 3 wooden veneers to form a surface layer and a bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack, and the thickness of the board stack is 41mm;

[0040] Step 5: preheat the board stack obtained in step 4 under heating conditions, the preheating temperature is 40° C., the treatment time is 35 min, and a slab is obtained after pre-pressing. The slab is then hot-pressed at a temperature of 140° C., a pressure of 4.0 MPa, and a hot-pressing time of 49.2 min to obtain a bamboo-wood composite plywood, which is then sawed to the edges to obtain a finished plywood.

[0041] The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 15 parts of expansion aid; the expansion aid includes 2 parts by weight of sodium bicarbonate, 0.5 parts by weight of alum, 0.8 parts by weight of sodium hydroxide, 2 parts by weight of dioctyl phthalate, 10 parts by weight of flour and 6 parts by weight of calcium carbonate.

[0042] Example 3

[0043] This embodiment provides a method for manufacturing a homogeneous bamboo-wood composite plywood, comprising the following steps:

[0044] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0045] Step 2: Apply the coating adhesive containing phenolic resin glue and expansion aid to the surface of the wood veneer to obtain the coated wood veneer. The viscosity of the adhesive is controlled at 3000cps, and the amount of the adhesive applied to the surface of the wood veneer is 400g / m 2 ;

[0046] Step 3: Combine the impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2, in a combination manner of alternately stacking one glue-coated wood veneer and one impregnated bamboo material, for a total of 10 layers, to obtain a core layer;

[0047] Step 4: symmetrically use 4 wooden veneers to form a surface layer and a bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack, and the thickness of the board stack is 35mm;

[0048] Step 5: preheat the board stack obtained in step 4 under heating conditions, the preheating temperature is 42° C., the treatment time is 30 min, and a slab is obtained after pre-pressing. The slab is then hot-pressed at a temperature of 140° C., a pressure of 4.0 MPa, and a hot-pressing time of 35 min to obtain a bamboo-wood composite plywood, which is then sawed to the edges to obtain a finished plywood.

[0049] The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 12 parts of expansion aid; the expansion aid includes 1 part of sodium bicarbonate, 0.3 parts of alum, 0.6 parts of sodium hydroxide, 1.5 parts of dioctyl phthalate, 8 parts of flour and 5 parts of calcium carbonate in mass parts.

[0050] Example 4

[0051] This embodiment provides a method for manufacturing a homogeneous bamboo-wood composite plywood, comprising the following steps:

[0052] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0053] Step 2: Apply the coating adhesive containing phenolic resin glue and expansion aid to the surface of the wood veneer to obtain the coated wood veneer. The viscosity of the adhesive is controlled at 2000cps, and the amount of the adhesive applied to the surface of the wood veneer is 350g / m 2 ;

[0054] Step 3: Combine the impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2, in a combination method of alternately stacking one glue-coated wood veneer and two impregnated bamboo materials, for a total of 15 layers, to obtain a core layer;

[0055] Step 4: symmetrically use 3 wooden veneers to form a surface layer and a bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack, and the thickness of the board stack is 25 mm;

[0056] Step 5: preheat the board stack obtained in step 4 under heating conditions, the preheating temperature is 30° C., the treatment time is 25 min, and a slab is obtained after pre-pressing. The slab is then hot-pressed at a temperature of 130° C., a pressure of 3.0 MPa, and a hot-pressing time of 20 min to obtain a bamboo-wood composite plywood, which is then sawed to the edges to obtain a finished plywood.

[0057] The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 10 parts of expansion aid; the expansion aid includes 2 parts by weight of sodium bicarbonate, 0.2 parts by weight of alum, 0.5 parts by weight of sodium hydroxide, 1 part by weight of dioctyl phthalate, 5 parts by weight of flour and 3 parts by weight of calcium carbonate.

[0058] Example 5

[0059] This embodiment provides a method for manufacturing a homogeneous bamboo-wood composite plywood, comprising the following steps:

[0060] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0061] Step 2: Apply the coating adhesive containing phenolic resin glue and expansion aid to the surface of the wood veneer to obtain the coated wood veneer. The viscosity of the adhesive is controlled at 3500cps, and the amount of the adhesive applied to the surface of the wood veneer is 450g / m 2 ;

[0062] Step 3: Combine the impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2, in a combination method of alternately stacking one glue-coated wood veneer and two impregnated bamboo materials, for a total of 15 layers, to obtain a core layer;

[0063] Step 4: symmetrically use 5 wooden veneers to form a surface layer and a bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack, and the thickness of the board stack is 45mm;

[0064] Step 5: preheat the board stack obtained in step 4 under heating conditions, the preheating temperature is 45° C., the treatment time is 35 min, and a slab is obtained after pre-pressing. The slab is then hot-pressed at a temperature of 150° C., a pressure of 5.0 MPa, and a hot-pressing time of 54 min to obtain a bamboo-wood composite plywood, which is then sawed to the edges to obtain a finished plywood.

[0065] The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 15 parts of expansion aid; the expansion aid includes 0.5 parts of sodium bicarbonate, 0.5 parts of alum, 0.8 parts of sodium hydroxide, 2 parts of dioctyl phthalate, 10 parts of flour and 6 parts of calcium carbonate in mass parts.

[0066] Comparative Example 1

[0067] This comparative example provides a method for manufacturing a bamboo-wood composite plywood, comprising the following steps:

[0068] Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material;

[0069] Step 2: Apply the coating adhesive containing phenolic resin glue and flour to the surface of the wood veneer to obtain the coated wood veneer. The viscosity of the adhesive is adjusted to 3000cps, and the amount of the adhesive applied to the surface of the wood veneer is 400g / m 2 ;

[0070] Step 3: Combine the impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2, in a combination method of alternately stacking one glue-coated wood veneer and two impregnated bamboo materials, for a total of 15 layers, to obtain a core layer;

[0071] Step 4: symmetrically use 3 wooden veneers to form a surface layer and a bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack, and the thickness of the board stack is 41mm;

[0072] Step 5: preheat the board stack obtained in step 4 under heating conditions, the preheating temperature is 40°C, the treatment time is 25 minutes, and a slab is obtained after pre-pressing. The slab is then hot-pressed at a temperature of 140°C, a pressure of 4.0 MPa, and a hot-pressing time of 49.2 minutes to obtain a bamboo-wood composite plywood. After sawing and milling the edges, the holes and gaps on the edges of the boards are patched to obtain a finished plywood.

[0073] The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 10 parts of flour.

[0074] Application Example 1

[0075] The finished plywood obtained in Examples 1-2 and Comparative Example 1 was used as the test object, and the test was carried out using the GB / T19536-2015 "Plywood for Container Bottom Plate" standard. The results are shown in the following table:

[0076]

[0077]

[0078] Result analysis: It can be seen from the above experimental data that the plywood prepared by the present invention has better uniformity in density and mechanical strength, and the expected purpose of the present invention is achieved.

[0079] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for manufacturing a homogeneous bamboo-wood composite plywood, characterized in that: The following steps are involved: Step 1: impregnating the woven bamboo curtain with phenolic resin and then drying it to obtain the impregnated bamboo material; Step 2: applying a coating adhesive comprising a phenolic resin glue and an expansion aid to the surface of the wood veneer to obtain a glue-coated wood veneer; Step 3: combining the glue-impregnated bamboo material obtained in step 1 and the glue-coated wood veneer obtained in step 2 to obtain a core layer; Step 4: Use 3-5 pieces of wood veneer symmetrically to form the surface layer and the bottom layer, and then combine the surface layer, the core layer and the bottom layer to obtain a board stack; Step 5: preheat the board stack obtained in step 4 under heating conditions, obtain a slab after pre-pressing, and then hot-press the slab to obtain a bamboo-wood composite plywood, and then obtain a finished plywood after sawing and trimming.

2. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: The coating adhesive is prepared by mixing 100 parts of phenolic resin glue and 10-15 parts of expansion aid.

3. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 2, characterized in that: The expansion aid comprises 0.5-2 parts by weight of sodium bicarbonate, 0.2-0.5 parts by weight of alum, 0.5-0.8 parts by weight of sodium hydroxide, 1-2 parts by weight of dioctyl phthalate, 5-10 parts by weight of flour and 3-6 parts by weight of calcium carbonate.

4. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: The viscosity of the coating adhesive is 2000cps-3500cps.

5. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: In the step 2, the adhesive applied to the surface of the wood veneer is 350-450g / m 2 .

6. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: The core layer in step three is composed of a glue-coated wooden veneer and a glue-impregnated bamboo material alternately stacked, or a glue-coated wooden veneer and two glue-impregnated bamboo materials alternately stacked.

7. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 6, characterized in that: The total number of the core layer is 6-15 layers.

8. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: The thickness of the plate stack assembly in step 4 is 25-45 mm.

9. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: The temperature of the preheating treatment in step 5 is 30-45° C., and the treatment time is 25-35 minutes.

10. The method for manufacturing a homogeneous bamboo-wood composite plywood according to claim 1, characterized in that: In the step 5, the hot pressing temperature of the slab is 130-150° C., the pressure is 3.0-5.0 MPa, and the hot pressing time is calculated based on the thickness of the slab stack 0.8-1.2 min / mm.

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