A phenolic resin composite flame retardant material and preparation method thereof

Abstract

The present invention discloses a phenolic resin composite flame retardant material and a preparation method thereof, which is prepared from the following raw materials in parts by weight: 282-390 parts of phenolic resin, 868-1155 parts of urea-formaldehyde resin, 8-15 parts of aluminum hydroxide, 10-20 parts of borax, and 1-8 parts of nanocellulose. The phenolic resin ratio of the present invention is less than 30%, the final material is light-colored, and can be better applied to different scenes, and the oxygen index of the present invention exceeds 50, and the flame retardant performance of the treated glued wood reaches the B1 (B) grade requirement specified in the GB 8624-2012 standard. The prepared flame retardant can be coated on the surface of glued wood, thereby improving the fire retardant performance of glued wood.

Description

Technical Field

[0001] The invention relates to a flame retardant material, in particular to a phenolic resin composite flame retardant material and a preparation method thereof. Background Art

[0002] Glued laminated timber (GLT) is an engineered wood product made by laminating and gluing three or more layers of wood plies along the grain. It makes up for the defects of small diameter, low strength and uneven material of artificial forest wood. Since the beginning of the 21st century, glued laminated timber has begun to be used as a green building material in public buildings such as gymnasiums, exhibition halls, swimming pools and bridge engineering fields. It can be seen that GLT is constantly being widely used in large public buildings, meeting the requirements of green development in my country's construction industry and has broad application prospects. However, wood is a combustible material, and it is of great significance to improve the fire retardant properties of glued laminated timber.

[0003] There are two main ways to flame retardant glued wood. One is to pre-treat the wood raw materials; the other is to apply fire retardant coatings to the entire glued wood. Among them, the use of fire retardant coatings is simple to operate, has significant effects, and is widely used. Glued wood fire retardant coatings mainly include organic non-expanding fire retardant coatings (usually composed of organic resins containing halogens and flame retardant elements such as nitrogen and phosphorus, as well as various flame retardants and inorganic pigments and fillers), inorganic non-expanding fire retardant coatings (mainly composed of water glass, silica sol, phosphate, cement and such as alumina, asbestos powder, calcium carbonate, oxide casting, titanium dioxide, etc.), and expanding fire retardant coatings (composed of film-forming substances, foaming agents and high carbon content substances).

[0004] Commonly used flame retardants in the prior art include halogen flame retardants, organophosphorus flame retardants, nitrogen flame retardants, silicon flame retardants, etc. Among them, halogen flame retardants have the disadvantages of easily generating hydrogen halide gas during combustion, which is harmful to human health and environmental safety; silicon flame retardants are expensive and need to be used in combination with other flame retardants; phosphorus flame retardants are added in large amounts and will reduce the performance of polymer materials.

[0005] The flame retardant coating in the prior art is dark in color, which will affect the color of the final finished glulam when used, making it unsightly and having large color limitations. It will also affect or cover the texture of the wood itself, losing the beauty of the wood itself.

[0006] Therefore, there is a need for a flame retardant coating that can control costs while ensuring flame retardant properties and does not affect the original color of the wood. Summary of the invention

[0007] In order to solve the above technical problems, the purpose of the present invention is to provide a phenolic resin composite flame retardant material with good flame retardancy and a preparation method thereof.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides a phenolic resin composite flame retardant material, characterized in that it is prepared from the following raw materials in parts by weight: 282 to 390 parts of phenolic resin, 868 to 1155 parts of urea-formaldehyde resin, 8 to 15 parts of aluminum hydroxide, 10 to 20 parts of borax, and 1 to 8 parts of nanocellulose.

[0009] In a preferred technical solution, the nanocellulose is cellulose nanofibrils, cellulose nanocrystals, etc.

[0010] The preparation method of the phenolic resin composite flame retardant material comprises the following steps:

[0011] Step 1, add formaldehyde aqueous solution to a reaction kettle, adjust the pH value of the formaldehyde aqueous solution to 7.0-8.2 with sodium hydroxide solution, add urea, heat to 90-96° C., and keep warm for 28-33 minutes to obtain reaction system I;

[0012] Step 2: adding formic acid to adjust the pH value of the reaction system I obtained in step 1 to 4.0-4.7, lowering the system temperature to 40-45° C., adding phenol, raising the temperature to 90-95° C. within 30-40 minutes, and keeping the temperature at this temperature for 10-20 minutes to obtain a reaction system II;

[0013] Step 3, adding sodium hydroxide solution to adjust the pH value of the reaction system II obtained in step 2 to 6.7-7.0, cooling to 40° C., adding formaldehyde solution, heating to 90° C. and keeping warm for 30 min to obtain a reaction system III;

[0014] Step 4: Determine the viscosity of the sample of reaction system III obtained in step 3, cool to 30-40° C., add aluminum hydroxide, borax and nanocellulose, mix well and then discharge.

[0015] In the above preparation method, the added amount of each raw material is calculated in parts by weight: 896-1032 parts of formaldehyde solution and 550-630 parts of urea in step one, 130-170 parts of phenol in step two, 224-258 parts of formaldehyde solution in step three, 8-15 parts of aluminum hydroxide, 10-20 parts of borax, and 1-8 parts of nanocellulose in step four.

[0016] Furthermore, the concentration of the formaldehyde solution is 37 wt %.

[0017] Step 4: The sample viscosity is 20 to 70 seconds at 30°C using a QND-4 viscometer.

[0018] Another method for preparing the phenolic resin composite flame retardant material comprises the following steps:

[0019] Step 1, synthesizing urea-formaldehyde resin, taking formaldehyde solution, adjusting the pH value of the formaldehyde aqueous solution to 7.0-8.2 with sodium hydroxide solution, adding urea for the first time, heating to 90-96°C, keeping warm for 28-33min, then adjusting the pH value to 4.0-4.7 with formic acid, reacting at 90-96°C for 20-30min, taking a sample of the reaction solution and mixing it with water, when a white precipitate appears, this stage ends; adjusting the pH value of the reaction solution to 6.7-7.0 with sodium hydroxide solution, cooling to 70-72°C, dehydrating, the dehydration amount is 22-25% of the total amount of raw materials, adding urea for the second time, polycondensing at 60-65°C for 25-30min, cooling to 18-30°C and discharging;

[0020] Step 2, synthesizing phenolic resin, adding phenol, sodium hydroxide and water into a reaction kettle in sequence and stirring, keeping the temperature at 40-46°C, adding formaldehyde solution for the first time, then heating the reaction solution to 92-95°C within 50-60min, keeping the temperature for 13-16min, cooling to 40°C, adding formaldehyde solution for the second time, slowly heating to 92-95°C, keeping the temperature for 25-33min, sampling and measuring viscosity, when the viscosity reaches 100-500mPa·s, 20°C, rapidly cooling to below 40°C and discharging;

[0021] Step 3: Evenly mix the urea-formaldehyde resin synthesized in step 1, the phenol-formaldehyde resin synthesized in step 2, aluminum hydroxide, borax and nanocellulose.

[0022] In the above preparation method, the added amount of each raw material is calculated in parts by weight: 965-1050 parts of formaldehyde solution and 550-630 parts of urea in step one, 130-170 parts of phenol and 175-204 parts of formaldehyde solution in step two, and 8-15 parts of aluminum hydroxide, 10-20 parts of borax and 1-8 parts of nanocellulose in step three.

[0023] Furthermore, the concentration of the formaldehyde solution is 37 wt %.

[0024] In step 1, the amount of urea added for the first time is 468-504 parts, and the amount of urea added for the second time is 82-126 parts; in step 2, the amount of formaldehyde solution added for the first time is 140-163 parts, and the amount of formaldehyde solution added for the second time is 35-41 parts.

[0025] The advantages of the present invention are:

[0026] 1. The proportion of phenolic resin in the present invention is less than 30%, and the final material is light-colored, which can be better applied to different scenes;

[0027] 2. The oxygen index of the present invention exceeds 50, and the flame retardant performance of the glued laminated wood after being coated with the surface flame retardant coating reaches the B1 (B) grade requirement specified in the GB8624-2012 standard.

[0028] 3. Conventional phenolic resins are dark in color, which affects the color of the product itself. The flame retardant adhesive obtained by the present invention is light in color and will not cover or affect the color of the wood itself.

[0029] 4. The present invention can achieve a synergistic enhancement effect by compounding a variety of materials, thereby ensuring flame retardancy while controlling the cost of flame retardants. DETAILED DESCRIPTION

[0030] Embodiment 1:

[0031] Ingredients: calculated by weight, 1120 parts of formaldehyde solution with a concentration of 37wt%, 550 parts of urea, 130 parts of phenol, 8 parts of aluminum hydroxide, 10 parts of borax, and 2 parts of cellulose nanofibrils.

[0032] The phenolic resin composite flame retardant material is synthesized by reacting according to the following steps.

[0033] Step 1, add 896 parts of formaldehyde aqueous solution to a reaction kettle, adjust the pH value of the formaldehyde aqueous solution to 7.1 with sodium hydroxide solution, add 550 parts of urea, heat to 91° C.), and keep warm for 29 minutes to obtain a reaction system I;

[0034] Step 2: adding formic acid to adjust the pH value of the reaction system I obtained in step 1 to 4.1, lowering the system temperature to 41°C, adding 130 parts of phenol, raising the temperature to 90°C within 31 minutes, and keeping the temperature at this temperature for 11 minutes to obtain a reaction system II;

[0035] Step 3, adding sodium hydroxide solution to adjust the pH value of the reaction system II obtained in step 2 to 6.8, cooling to 40° C., adding 224 parts of formaldehyde solution, heating to 90° C. and keeping warm for 30 minutes to obtain a reaction system III;

[0036] Step 4: Measure the viscosity of the sample of reaction system III obtained in step 3, the viscosity is 20-70s on a QND-4 viscometer at 30° C. After cooling to 31° C., add 8 parts of aluminum hydroxide, 10 parts of borax and 2 parts of nanocellulose, mix well and discharge.

[0037] Thus, a light-colored phenolic resin composite flame retardant material is obtained. The oxygen index of the phenolic resin composite flame retardant material is greater than 50 as determined.

[0038] Embodiment two:

[0039] Ingredients: calculated by weight, 1254 parts of formaldehyde solution with a concentration of 37wt%, 630 parts of urea, 170 parts of phenol, 15 parts of aluminum hydroxide, 20 parts of borax, and 8 parts of nanocellulose.

[0040] Step 1, synthesizing urea-formaldehyde resin, taking 1050 parts of formaldehyde solution, adjusting the pH value of the formaldehyde aqueous solution to 7.1 with sodium hydroxide solution, adding 504 parts of urea for the first time, heating to 91°C, keeping warm for 28 minutes, then adjusting the pH value to 4.1 with formic acid, reacting at 91°C for 21 minutes, taking a sample of the reaction solution and mixing it with water, when a white precipitate appears, this stage is over; adjusting the pH value of the reaction solution to 6.7 with sodium hydroxide solution, cooling to 70°C, dehydrating, the dehydration amount is 22% of the total amount of raw materials, adding 126 parts of urea for the second time, polycondensing at 62°C for 25 minutes, cooling to 19°C and discharging;

[0041] Step 2, synthesizing phenolic resin, adding 170 parts of phenol, 2 parts of sodium hydroxide and 80 parts of water into a reactor in sequence, stirring, keeping the temperature at 40°C, adding 163 parts of formaldehyde solution for the first time, then heating the reaction solution to 92°C within 51 minutes, keeping the temperature for 15 minutes, cooling to 40°C, adding 41 parts of formaldehyde solution for the second time, slowly heating to 92°C, keeping the temperature for 25 minutes, sampling to measure the viscosity, and when the viscosity reaches 100-500mPa·s, 20°C, quickly cooling to below 40°C and discharging;

[0042] Step 3: Evenly mix the urea-formaldehyde resin synthesized in step 1, the phenol-formaldehyde resin synthesized in step 2, 15 parts of aluminum hydroxide, 20 parts of borax, and 8 parts of nanocellulose.

[0043] Thus, a light-colored phenolic resin composite flame retardant material is obtained. The oxygen index of the phenolic resin composite flame retardant material is greater than 50 as determined.

Claims

1. A method for preparing a phenolic resin composite flame retardant material, characterized in that: The steps include: Step 1, add 896-1032 parts of formaldehyde aqueous solution to a reaction kettle, adjust the pH value of the formaldehyde aqueous solution to 7.0-8.2 with sodium hydroxide solution, add 550-630 parts of urea, heat to 90-96° C., and keep warm for 28-33 minutes to obtain a reaction system I; Step 2: adding formic acid to adjust the pH value of the reaction system I obtained in step 1 to 4.0-4.7, lowering the system temperature to 40-45° C., adding 130-170 parts of phenol, raising the temperature to 90-95° C. within 30-40 minutes, and keeping the temperature at this temperature for 10-20 minutes to obtain a reaction system II; Step 3, adding sodium hydroxide solution to adjust the pH value of the reaction system II obtained in step 2 to 6.7-7.0, cooling to 40° C., adding 224-258 parts of formaldehyde solution, heating to 90° C. and keeping warm for 30 minutes to obtain a reaction system III; Step 4: Determine the viscosity of the sample of reaction system III obtained in step 3, cool to 30-40° C., add 8-15 parts of aluminum hydroxide, 10-20 parts of borax and 1-8 parts of nanocellulose, mix well and then discharge.

2. The method for preparing a phenolic resin composite flame retardant material according to claim 1, characterized in that: The concentration of the formaldehyde solution is 37 wt %.

3. The method for preparing a phenolic resin composite flame retardant material according to claim 1, characterized in that: Step 4: The sample viscosity is 20 to 70 seconds at 30°C using a QND-4 viscometer.

4. A method for preparing a phenolic resin composite flame retardant material, characterized in that: The steps include: Step 1, synthesizing urea-formaldehyde resin, taking 965-1050 parts of formaldehyde solution, adjusting the pH value of the formaldehyde aqueous solution to 7.0-8.2 with sodium hydroxide solution, adding 468-504 parts of urea for the first time, heating to 90-96°C, keeping warm for 28-33 minutes, then adjusting the pH value to 4.0-4.7 with formic acid, reacting at 90-96°C for 20-30 minutes, taking a sample of the reaction solution and mixing it with water, when a white precipitate appears, this stage ends; adjusting the pH value of the reaction solution to 6.7-7.0 with sodium hydroxide solution, cooling to 70-72°C, dehydrating, the dehydration amount is 22-25% of the total amount of raw materials, adding 82-126 parts of urea for the second time, polycondensing at 60-65°C for 25-30 minutes, cooling to 18-30°C and discharging; Step 2, synthesizing phenolic resin, adding 130-170 parts of phenol, sodium hydroxide and water to a reactor in sequence and stirring, keeping the temperature at 40-46°C, adding 140-163 parts of formaldehyde solution for the first time, then heating the reaction solution to 92-95°C within 50-60 minutes, keeping the temperature for 13-16 minutes, cooling to 40°C, adding 35-41 parts of formaldehyde solution for the second time, slowly heating to 92-95°C, keeping the temperature for 25-33 minutes, sampling and measuring the viscosity, and when the viscosity reaches 100-500mPa·s, 20°C, rapidly cooling to below 40°C and discharging; Step 3: Evenly mix the urea-formaldehyde resin synthesized in step 1, the phenol-formaldehyde resin synthesized in step 2, 8-15 parts of aluminum hydroxide, 10-20 parts of borax, and 1-8 parts of nanocellulose.

5. The method for preparing a phenolic resin composite flame retardant material according to claim 4, characterized in that: The concentration of the formaldehyde solution is 37 wt %.