Functionalized density board and method of making the same

Abstract

The application discloses a kind of functional density board.It is composed of wood fiber, binder and multifunctional additive, by mixing and heating the pulverized agricultural and forestry waste with starch, water, into paste, then adding inorganic functional additive, silane coupling agent and ammonium persulfate, stirring reaction, cold-pressing forming, standing, pulverizing to obtain multifunctional additive, the inorganic functional additive is composed of 10-35wt% attapulgite, 10-15wt% dolomite, 0-15wt% tourmaline, 0-10wt% potassium feldspar, 0-10wt% calcite, 15-30wt% water glass and 5-15wt% calcium sulfate.Compared with prior art, the density board of the application overcomes the problem that existing density board is flammable and prone to mold when damp, has good flame retardant, smoke suppression, antibacterial and anticorrosive properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of density board, and particularly relates to a functionalized density board. BACKGROUND

[0002] The density board has smooth and even surface, fine material, stable performance, and good decoration on the surface of the board, and is widely applied in domestic furniture, decoration, building, handicraft and packaging. However, the wood material itself is flammable and is prone to mildew when wet, and with the improvement of the living standard of residents in China, higher requirements are put forward for the functional properties (flame retardancy, antibacterial property, corrosion resistance, etc.) of the density board. SUMMARY

[0003] In order to overcome the problems of flammability and mildew of the density board when wet, the present application provides a functionalized density board.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] The functionalized density board is composed of wood fibers, a binder and a multifunctional additive, characterized in that the multifunctional additive is prepared by a method comprising the following steps:

[0006] The pulverized agricultural and forestry waste is mixed with starch and water and heated, and after becoming a paste, inorganic functional additives, silane coupling agent and ammonium persulfate are added, and after stirring for a certain time, the mixture is cooled and cold-pressed into a shape, and after standing for a certain time, it is pulverized to obtain the multifunctional additive, wherein the mass ratio of the agricultural and forestry waste to the starch is 10-30:1-5;

[0007] The mass of the inorganic functional additives, the silane coupling agent and the ammonium persulfate is 5-10%, 1-3% and 0.2-0.5% of the total mass of the agricultural and forestry waste and the starch, respectively;

[0008] The inorganic functional additives are composed of 10-35wt% attapulgite, 10-15wt% dolomite, 0-15wt% tourmaline, 0-10wt% potassium feldspar, 0-10wt% calcite, 15-30wt% water glass and 5-15wt% calcium sulfate.

[0009] Preferably, the agricultural and forestry waste is straw, bark and / or wheat straw.

[0010] Preferably, the pulverized agricultural and forestry waste is mixed with starch and water and heated to a temperature of 50-70℃.

[0011] Preferably, the stirring time is 30-60min.

[0012] Preferably, the standing time is 12-48h.

[0013] Preferably, the mass ratio of the agricultural and forestry waste to the starch is 20-30:5.

[0014] Preferably, the mass of the water is 20-40% of the total mass of the agricultural and forestry waste and the starch.

[0015] Preferably, in the functionalized density board, the mass ratio of the multifunctional additive to the wood fiber is 1:2-4.

[0016] The preparation method of the functionalized density board comprises the following steps: uniformly mixing wood fiber, a binder and a multifunctional additive, and then performing hot pressing and cold pressing to obtain the functionalized density board.

[0017] Preferably, the amount of the binder is 10-25wt% of the total amount of the material.

[0018] The binder is a urea-formaldehyde resin binder. The urea-formaldehyde resin binder can be prepared by a urea stepwise addition method using 45-65wt% of aldehyde and 35-55wt% of urea, wherein the aldehyde is formaldehyde or glutaraldehyde, and the specific operation process is as follows:

[0019] First, 50-65wt% of the total amount of urea is added to the aldehyde, and the temperature is controlled at 70-85℃, the pH is controlled at 7-8.5, and the reaction is performed for 20-50min;

[0020] Then, 20-35wt% of the total amount of urea is added, the temperature is controlled at 75-95℃, the pH is controlled at 4.5-6.5, and the reaction is performed for 30-90min;

[0021] Finally, the remaining urea is added, the temperature is controlled at 65-85℃, the pH is controlled at 7-8.5, and the reaction is performed for 10-40min.

[0022] Preferably, the hot pressing temperature is 190-240℃, the pressure is 12-18 MPa, and the time is 50-100s.

[0023] Preferably, the cold pressing pressure is 5-8 MPa, and the time is 120-300s.

[0024] Beneficial effects:

[0025] The density board of the present application overcomes the problems of flammability and mold growth in the presence of moisture of the existing density board, and has good flame retardation, smoke suppression, antibacterial and corrosion resistance. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The heat release rate (HRR) curve of the density board (A) without adding a multifunctional additive and the functionalized density board (B) with adding a multifunctional additive.

[0027] Figure 2Specific extinction area (SEA) curves of the density board without adding multifunctional additive (A) and the functionalized density board with adding multifunctional additive (B).

[0028] Figure 3 Smoke production rate (SPR) curves of the density board without adding multifunctional additive (A) and the functionalized density board with adding multifunctional additive (B).

[0029] Figure 4 Total smoke production (TSP) curves of the density board without adding multifunctional additive (A) and the functionalized density board with adding multifunctional additive (B).

[0030] Figure 5 CO2 release rate (CO2P) curves of the density board without adding multifunctional additive (A) and the functionalized density board with adding multifunctional additive (B).

[0031] Figure 6 Mold proof photos of the density board without adding multifunctional additive (left sample in each culture dish) and the functionalized density board with adding multifunctional additive (right sample in each culture dish) against (a, b) Alternaria alternata, (c, d) Aspergillus niger, (e, f) mixed bacteria. DETAILED DESCRIPTION

[0032] The technical solutions of the present application are further described below in combination with examples.

[0033] Example 1

[0034] (I) Preparation of multifunctional additive:

[0035] (1) The straw was crushed into fine powder and passed through a 100 mesh sieve for standby use;

[0036] (2) 300 g of straw powder and 70 g of starch were stirred and mixed, then 100 g of water was added and stirred and heated to 60°C until a uniform paste was formed;

[0037] (3) 25 g of mixed additive (composed of 35 wt% attapulgite, 10 wt% dolomite, 5 wt% potassium feldspar, 5 wt% calcite, 30 wt% water glass and 15 wt% calcium sulfate) was added to the above paste, stirred uniformly, 10 g of silane coupling agent KH560 and 2 g of ammonium persulfate were added, and stirred at 300 rpm for 60 min;

[0038] (4) The temperature was reduced to room temperature, cold-pressed into shape, and crushed to 100 mesh after standing for 36 h to obtain the multifunctional additive.

[0039] (II) Preparation of urea-formaldehyde resin adhesive:

[0040] (1) 95.0 g of formaldehyde was heated in a water bath to 75°C, and during the heating process, the pH was controlled to be 7.5, 32.5 g of urea was added, and the reaction was stirred for 30 min, and the pH was controlled to be 7.0 during the reaction;

[0041] (2) The pH of the above solution was adjusted to 5.0, and the temperature was raised to 90°C, 16.0 g of urea was added, and the reaction was stirred for 50 min, and the pH was maintained at 4.5 during the reaction;

[0042] (3) The pH of the above mixture was adjusted to 7.5, and the temperature was lowered to 75°C, 10.0 g of urea was added, and the reaction was stirred for 15 min, and the pH was controlled to be 7.5 during the reaction;

[0043] (4) After standing and cooling to room temperature, the adhesive was obtained.

[0044] (Three) Preparation of functionalized density board:

[0045] (1) The raw wood was crushed into wood fibers with a length of 3 cm, and was steamed at 75°C for 10 h, and the water content was controlled to be 40-60%, and then was dried at 180°C to obtain modified wood fibers with a water content of 3-6%;

[0046] (2) 250 g of modified wood fibers and 70 g of multifunctional additives were weighed, and 85 g of adhesive was added and stirred thoroughly;

[0047] (3) The above mixture was placed in a 200*200*10mm mold, and the temperature of the hot press was adjusted to 210°C, the pressure was 14 MPa, and the hot pressing time was 60 s;

[0048] (4) The wood board after hot pressing was cold pressed at 6 MPa for 200 s;

[0049] (5) The cold-pressed wood board was placed at room temperature for 12 h, and the edges were cut to obtain the functionalized density board.

[0050] Performance test results of functionalized density board:

[0051] The static bending strength and elastic modulus can meet the standard of GB / T 31765-2015 ordinary type high density fiberboard.

[0052] Cone calorimeter test HRR=290 kW / m 2 , THR=52 MJ / m 2 , COP=0.0042 g / s, CO2P=0.23 g / s, SPR=0.013 m 2 / s, RSR=1.3 m 2 ·s / m 2 , TSP=1.20 m 2 , TSR=138 m 2 / m 2 , SEA = 93 m 2 / kg, the limiting oxygen index reaches B1 level.

[0053] According to the test method of GB / T 18261-2013, after 7 days of inoculation, 28 days of mildew prevention experiment proves that the control efficacy can reach 82%, reaching the mildew level of LY / T 2230-2013 artificial board standard.

[0054] According to GB / T 13942.1-2009 Wood durability Part 1: Natural resistance Laboratory test method, after 7 days of inoculation, 84 days of corrosion experiment, the mass loss rate is 4.8%, reaching the I level of GB / T 13942.1-2009 strong corrosion artificial board standard.

[0055] Example 2

[0056] (I) Preparation of multifunctional additive:

[0057] (1) The straw and bark were crushed into fine powder, respectively, and passed through a 100 mesh sieve for standby;

[0058] (2) 200g of straw powder, 100g of bark powder and 50g of starch were stirred and mixed, then 125g of water was added, and stirred and heated to 50℃ until a uniform paste was formed;

[0059] (3) 30g of mixed additive (composed of 30wt% attapulgite, 5wt% tourmaline, 10wt% dolomite, 10wt% potassium feldspar, 5wt% calcite, 30wt% water glass and 10wt% calcium sulfate) was added to the above paste, stirred uniformly, 7.5g of silane coupling agent KH560 and 1.5g of ammonium persulfate were added, and stirred at 500 rpm for 30 min;

[0060] (4) The temperature was reduced to room temperature, and cold-pressed into a shape, and crushed to 100 mesh after standing for 24h to obtain the multifunctional additive.

[0061] (II) Preparation of urea-formaldehyde resin adhesive:

[0062] (1) 95.0g of formaldehyde was heated in water bath to slowly warm up to 80℃, and 35.0g of urea was added during the warming process, and stirred for 50min, and the pH was controlled at 7.5 during the reaction;

[0063] (2) The pH of the above mixture was adjusted to 5.5, and the temperature was raised to 80℃, 15.0g of urea was added, and stirred for 80min, and the pH was maintained at 5.5 during the reaction;

[0064] (3) The mixture is adjusted to pH = 7.0, cooled to 65℃, 10.0g urea is added, and stirred for 35min, and the pH is controlled at 7.0 during the reaction;

[0065] (4) After standing and cooling to room temperature, the adhesive is obtained.

[0066] (Three) Preparation of functionalized density board:

[0067] (1) The raw wood is crushed into wood fibers with a length of 5 cm, and is steamed at 85℃ for 8h with water control, the moisture content is 50%, and then is dried at 180℃ hot air to form modified wood fibers with a moisture content of 5%;

[0068] (2) 200g of modified wood fibers and 100g of multifunctional additives are weighed, and 50g of adhesive is added and stirred thoroughly;

[0069] (3) The mixture is laid in a 200*200*10mm mold, the temperature of the hot press is adjusted to 200℃, the pressure is 16MPa, and the hot pressing time is 60s;

[0070] (4) The wood board after hot pressing is cold pressed at 5MPa for 240s;

[0071] (5) The cold-pressed wood board is placed at room temperature for 12h, and the edges are cut to obtain the functionalized density board.

[0072] In addition, under the same conditions, a blank sample of density board without adding multifunctional additives is prepared.

[0073] Performance test results of functionalized density board:

[0074] The static bending strength and elastic modulus can reach the standard of GB / T 31765-2015 ordinary type high density fiberboard.

[0075] Cone calorimeter test HRR = 260 kW / m 2 , THR = 48 MJ / m 2 , COP = 0.0039 g / s, CO2P = 0.21 g / s, SPR = 0.012 m 2 / s, RSR = 1.1 m 2 ·s / m 2 , TSP = 1.18 m 2 , TSR = 132 m 2 / m 2 , SEA = 90 m 2 / kg, and the limiting oxygen index reaches B1 level.

[0076] Figures 1-5The HRR, SEA, SPR, TSP and CO2P profiles of the cone calorimeter test of the density board blank sample (A) and the functionalized density board (B) respectively, it can be seen that after adding the multifunctional additive of the application, the flame retardant performance of the density board is significantly improved.

[0077] According to the test method of GB / T 18261-2013, after 7 days of inoculation and 28 days of mildew prevention experiment, the control efficacy can reach 87%, reaching the mildew-proof grade of artificial board standard LY / T 2230-2013.

[0078] Figure 6 The mildew prevention photos of the density board blank sample (left) and the functionalized density board (right) against Alternaria alternata (a, b), Aspergillus niger (c, d) and mixed bacteria (e, f) respectively, it can be seen that after adding the multifunctional additive of the application, the growth of mold can be obviously inhibited, and the mildew-proof performance of the density board is significantly improved.

[0079] According to GB / T 13942.1-2009 Wood durability Part 1: Naturally durable wood - Laboratory test methods, after 7 days of inoculation and 84 days of corrosion resistance experiment, the mass loss rate is 3.9%, reaching the I-class strong corrosion resistance artificial board standard of GB / T 13942.1-2009.

[0080] Example 3

[0081] (I) Preparation of multifunctional additive:

[0082] (1) Straw, wheat straw and crushed into fine powder, respectively, pass through 100 mesh sieve, reserve;

[0083] (2) Stir and mix 150g of straw powder, 100g of wheat straw powder, 50g of bark powder and 75g of starch, then add 100g of water, stir and heat to 70℃ until a uniform paste is formed;

[0084] (3) Add 20g of mixed additives (composed of 25wt% attapulgite, 5wt% tourmaline, 15wt% dolomite, 10wt% potassium feldspar, 10wt% calcite, 25wt% water glass and 10wt% calcium sulfate) to the above paste, stir uniformly, add 5g of silane coupling agent KH560 and 1g of ammonium persulfate, stir at 300 rpm for 60 min;

[0085] (4) Reduce the temperature to room temperature, cold-press into shape, and crush to 100 mesh after standing for 48h, to obtain the multifunctional additive.

[0086] (II) Preparation of urea-formaldehyde resin adhesive:

[0087] (1) 65.0 g glutaraldehyde is heated in a water bath to slowly warm up to 80°C, and 45.0 g urea is added during the warming process while controlling pH = 7.0, and stirring for 50 min, and the pH is controlled to be 7.5 during the reaction;

[0088] (2) The pH of the above mixture is adjusted to 5.5, and the temperature is raised to 80°C, 15.0 g of urea is added, and stirring is carried out for 80 min, and the pH is maintained at 5.5 during the reaction;

[0089] (3) The pH of the above mixture is adjusted to 7.0, and the temperature is lowered to 65°C, 10.0 g of urea is added, and stirring is carried out for 35 min, and the pH is controlled to be 7.0 during the reaction;

[0090] (4) After standing and cooling to room temperature, the adhesive is obtained.

[0091] (Three) Preparation of functionalized density board:

[0092] (1) The raw wood is crushed into wood fibers with a length of 6 cm, and is steamed at 80°C for 10 h, and the water content is controlled to be 40%, and then is dried at 180°C hot air to become modified wood fibers with a water content of 4%;

[0093] (2) 250 g of modified wood fibers and 60 g of multifunctional additives are weighed, and 75 g of adhesive is added, and the mixture is stirred thoroughly;

[0094] (3) The above mixture is laid in a 200*200*10mm mold, and the temperature of the hot press is adjusted to 200°C, the pressure is 12 MPa, and the hot pressing time is 80 s;

[0095] (4) The wood board after hot pressing is cold pressed at 6 MPa for 210 s;

[0096] (5) The cold-pressed wood board is placed at room temperature for 18 h, and the edges are cut to obtain the functionalized density board.

[0097] Performance test results of the functionalized density board:

[0098] The static bending strength and elastic modulus can reach the standard of GB / T 31765-2015 ordinary type high-density fiberboard.

[0099] Cone calorimeter test HRR = 270 kW / m 2 , THR = 50 MJ / m 2 , COP = 0.0035 g / s, CO2P = 0.21 g / s, SPR = 0.011 m 2 / s, RSR = 1.1 m 2 ·s / m 2 , TSP = 1.15 m 2 , TSR = 131 m 2 / m 2 , SEA = 88 m 2 / kg, the limiting oxygen index reaches B1 level.

[0100] According to the test method of GB / T 18261-2013, after 7 days of inoculation, 28 days of mildew resistance experiment proves that the control efficacy can reach 77%, reaches the mildew resistance level of LY / T 2230-2013 artificial board standard.

[0101] According to GB / T 13942.1-2009 Wood durability Part 1: Natural resistance Laboratory test method, after 7 days of inoculation, 84 days of corrosion resistance experiment, the mass loss rate is 3.2%, reaches the I level of GB / T 13942.1-2009 strong corrosion resistance artificial board standard.

[0102] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement of the technical solutions recorded in the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A functionalized density board, consisting of wood fiber, binder and multifunctional additive, characterized in that: The multifunctional additive is prepared by a method comprising the following steps: The pulverized agricultural and forestry waste is mixed with starch and water, heated to form a paste, and then inorganic functional additives, silane coupling agent and ammonium persulfate are added, stirred and reacted for a certain time, cooled, cold-pressed, and then crushed after standing for a certain time to obtain the multifunctional additive, wherein the mass ratio of agricultural and forestry waste to starch is 10-30:1-5; The mass of inorganic functional additives, silane coupling agent and ammonium persulfate is 5-10%, 1-3% and 0.2-0.5% of the total mass of agricultural and forestry waste and starch, respectively; The inorganic functional additives are composed of 10-35wt% attapulgite, 10-15wt% dolomite, 0-15wt% tourmaline, 0-10wt% potassium feldspar, 0-10wt% calcite, 15-30wt% water glass and 5-15wt% calcium sulfate.

2. The functionalized density board of claim 1, wherein: The agricultural and forestry waste is straw, tree bark and / or wheat straw.

3. The functionalized density board of claim 1, wherein: Heating to a temperature of 50-70℃.

4. The functionalized density board of claim 1, wherein: The stirring and reaction time is 30-60min.

5. The functionalized density board of claim 1, wherein: The standing time is 12-48h.

6. The functionalized density board of claim 1, wherein: The mass ratio of agricultural and forestry waste to starch is 20-30:

5.

7. The functionalized density board of claim 1, wherein: The mass of water is 20-40% of the total mass of agricultural and forestry waste and starch.

8. The functionalized density board of claim 1, wherein: In the functionalized density board, the mass ratio of multifunctional additive to wood fiber is 1:2-4.

9. A method of making the functionalized density board of any one of claims 1-8, comprising: After the wood fiber, adhesive and multifunctional additive are thoroughly mixed, the functionalized density board is obtained by hot pressing and cold pressing.

10. The method of claim 9, wherein: The amount of adhesive is 10-25wt% of the total material; the hot pressing temperature is 190-240℃, the pressure is 12-18 MPa, the time is 50-100s, the cold pressing pressure is 5-8 MPa, and the time is 120-300s.

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