CN102975251A - Flame retardant for wood as well as preparation method and applications of flame retardant for wood - Google Patents

Abstract

The present invention relates to a kind of flame retardant, and its raw material comprises phosphoric acid, urea, catalyst, water, silica sol and boric acid; use. The flame retardant provided by the invention not only has a remarkable flame retardant effect, but also has better dimensional stability and anti-corrosion functions. In addition, the flame retardant also has the function of eliminating formaldehyde, which can effectively improve the environmental protection characteristics of the wood-based panel when used in the treatment of the wood-based panel. The wood flame retardant provided by the invention has a simple preparation method and low cost, which is far lower than the price of the existing domestic and foreign flame retardants.

Description

Wood flame retardant, preparation method and use thereof

technical field

The invention relates to the field of flame retardant materials, in particular to a wood flame retardant, a preparation method and an application thereof.

Background technique

Wood and its products are widely used in interior decoration, furniture manufacturing, house construction and exterior decoration. These materials are combustible materials, which are easy to cause fire, shrink when dry and expand when wet, and have poor dimensional stability. They are easy to rot when used outdoors. Improving the flame retardancy, dimensional stability and corrosion resistance of materials has become an issue of widespread concern all over the world.

At present, the most common method to prevent fires of wood and its products is to use flame retardants in these materials. Most of these flame retardants are based on compounds containing phosphorus, nitrogen, boron, aluminum and halogens. It is widely used because of its good performance, no toxic gas (except halogen flame retardants), no precipitation, no volatilization, low price, wide range of sources, and high safety.

For example, the article "Research on Wood Flame Retardant Treatment Process" (Author: Li Yanyun, etc.) published in the second issue of "Fine Chemical Industry" in 2000 discloses a phosphorus-nitrogen inorganic flame retardant, which is mainly composed of dicyandiamide , formaldehyde, urea, and ammonium dihydrogen phosphate in a certain proportion. This inorganic flame retardant is mainly used in solution form, such as by impregnating wood to obtain flame retardant effect. Phosphorus-nitrogen flame retardants have a flame-retardant synergistic effect, reduce the decomposition temperature, increase the formation of charcoal, reduce the generation of flammable gases, and reduce heat.

A Chinese patent application with publication date of April 5, 2000 and publication number CN1249325A discloses a fire retardant, which is mixed with urea, phosphoric acid, borax, boric acid, etc., and is suitable for cotton cloth, chemical fiber Flame retardant treatment of combustibles such as paper, wood, etc.

A Chinese patent application with a publication date of July 26, 2006 and a publication number of CN1807552A discloses a phosphorus-nitrogen composite flame retardant. The flame retardant is chemically reacted with urea and phosphoric acid and then added with a neutralizing agent such as ammonia. It is made by neutralization reaction and is suitable for flame retardant of combustibles such as textiles and wood products. The preparation method of the flame retardant is relatively simple, safe and environmentally friendly.

The Chinese patent with the patent number ZL200710122243.2 provides a flame retardant with the effect of absorbing formaldehyde for wood and wood-based panels and its preparation method. The flame retardant prepared by this technology is colorless, odorless and non-toxic , has the property of suppressing smoke, and has low preparation cost.

Although the flame retardants disclosed in the above documents have the advantages of simple manufacturing methods and low cost, they have poor anti-loss properties and do not contribute much to the dimensional stability and antiseptic effect of wood.

Contents of the invention

In order to overcome the technical defect of the single effect of the existing flame retardant and develop a new multifunctional flame retardant material, the purpose of the present invention is to provide a wood flame retardant.

Another object of the present invention is to provide a preparation method of wood flame retardant.

Another object of the present invention is to provide a use of a wood flame retardant.

Flame retardant provided by the invention comprises the following raw materials by weight:

Phosphoric acid: 20-200 parts;

Urea: 20-100 parts;

Catalyst: 0.1～1.0 parts;

Water: 40～250 parts;

Silica sol: 10-100 parts;

Boric acid: 1 to 15 parts;

The catalyst is composed of the following components by weight: 0.8-1.2 parts of tin chloride; 1.5-2.5 parts of copper sulfate; 0.8-1.2 parts of sodium chloride; 0.8-1.2 parts of ferric chloride; 0.8-1.2 parts of aluminum sulfate; 0.8-1.2 parts and 1.5-2.5 parts of zinc chloride.

When the wood flame retardant provided by the invention acts on wood, the silica sol contributes to the swelling of the wood cell wall and improves the retention of the flame retardant component (the polymerization product of phosphoric acid and urea under the action of a catalyst) in the cell wall. When the wood is dry, there are hydrogen bonds and intermolecular forces between the wood, flame retardant components, and nano-silica, so that the stability and loss resistance of the wood are also significantly improved. The wood flame retardant provided by the invention also contains boric acid, which can effectively improve the corrosion resistance of wood.

Preferably, the flame retardant comprises the following raw materials in parts by weight:

Phosphoric acid: 50-150 parts;

Urea: 30-60 parts;

Catalyst: 0.2～0.5 parts;

Water: 50-200 parts;

Silica sol: 20-60 parts;

Boric acid: 5-10 parts.

The phosphoric acid is an aqueous phosphoric acid solution with a mass percent concentration of 80-90%.

The silica sol can be selected from common commercially available products, wherein the content of silicon dioxide is about 20-30wt%.

The water is preferably demineralized water with a hardness lower than 8.

The present invention also provides the preparation method of described wood flame retardant, comprises the following steps:

(1) Add phosphoric acid into the reaction kettle, stir and heat to raise the temperature to 50-60°C;

(2) Add urea into the reaction kettle and stir evenly;

(3) When the temperature rises to 90-120°C, add a catalyst into the reaction kettle, and stop heating after the temperature rises to 130-140°C;

(4) Cool down the reaction kettle to 60-80°C, add water and boric acid, and stir evenly;

(5) When the temperature of the reactor is lowered to 20-30°C, add an inorganic base until the pH value is 8.5-9.5, then add silica sol into the reactor, and stir evenly.

Wherein, the various components of the catalyst can be mixed in any order of addition in advance, and then added into the reaction kettle as a whole.

Wherein, the inorganic base is sodium hydroxide or potassium hydroxide.

Wherein, the inorganic base is an aqueous solution with a mass percent concentration of 30-50%.

During the above preparation process, the stirring speed is 50-70 rpm.

In the step (3), after the temperature rises to 130-140° C., the heating is stopped when the volume of the reactants in the reactor increases to 2-3 times of the original volume.

The present invention also provides the use of the wood flame retardant described in any one of the above technical solutions as a wood dimension stabilizer.

The present invention also provides the use of the wood flame retardant described in any one of the above technical solutions as a wood preservative.

The flame retardant of the invention can not only play an excellent flame retardant effect, but also obviously improve the dimensional stability and corrosion resistance of wood, and has multiple composite functions.

The technical solution of the present invention has the following advantages:

1) The treatment agent of the present invention not only has a remarkable flame retardant effect, but also has better dimensional stability and anti-corrosion functions.

2) The preparation of the present invention has the function of eliminating formaldehyde. It is used in the treatment of wood-based panels such as plywood, which can effectively improve the environmental protection characteristics of wood-based panels.

3) The preparation method of the preparation of the present invention is simple and the cost is low. The manufacturing cost of the liquid treatment agent of the present invention with a solid content of about 40% is about 2,800 yuan/ton, which is far lower than the prices of existing domestic and foreign flame retardants.

Detailed ways

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

1. Prepare raw materials according to the following weight ratio:

Demineralized water (hardness below 8 degrees): 100kg;

Phosphoric acid (aqueous solution with mass concentration of 85%): 100kg;

Urea (nitrogen content is about 46.4%): 50kg;

Catalyst: 0.35kg;

Silica sol (mass fraction of silica is about 25%): 20kg;

Boric acid (content above 99%) 5kg.

Among them, the catalyst is a light yellow-green powder prepared by the Environmental Protection Flame Retardant Technology Center of the School of Materials Science and Technology, Beijing Forestry University. The preparation process is as follows: 1.0 parts of tin chloride, 2.0 parts of copper sulfate, 0.9 parts of sodium chloride, 1.1 parts of ferric chloride, 0.8 parts of aluminum sulfate, 1.2 parts of boric acid and 1.8 parts of zinc chloride are ground and mixed uniformly.

2. The preparation process is as follows:

1) Add phosphoric acid solution to a reaction kettle equipped with a stirrer, a thermometer and a condenser, stir and heat while stirring, so that the temperature rises to about 60°C;

2) Add urea into the reactor, and at the same time continue to stir the mixture of phosphoric acid and urea, so that the material is distributed and heated evenly;

3) When the temperature rises to 120°C, slowly and evenly add the catalyst to the reaction kettle to make the mixture react. At this time, the reaction material turns light green; continue heating until the temperature reaches about 135°C, and observe the reaction phenomenon while heating , as the temperature rises, the light green liquid gradually turns into a milky white viscous substance, the foam increases sharply, the temperature rises faster, the volume of the material expands rapidly, a large amount of gas is discharged from the condenser tube, and the volume of the reactant in the reactor increases Stop heating when it reaches about twice the original volume, and continue to stir. The materials in the reactor continue to react violently by their own heat release, and the temperature continues to rise. When the reaction becomes stable and the temperature begins to drop, it indicates that the reaction is complete;

4) When the temperature drops to about 70°C, add demineralized water and boric acid at a temperature of 50°C to the reaction kettle, and stir evenly;

5) When the temperature drops to about 30°C, adjust the pH value between 8.5-9.5 with sodium hydroxide solution (mass concentration 40%), and finally add silica sol into the reaction kettle and stir evenly;

6) Pour the resulting product into a container and store it for later use.

Product technical indicators:

Appearance: Transparent liquid

Solid content (wt%): 43

pH value: 8.5-9.5

Viscosity (coated - 4 cups) (25°C, S): 10.2

Specific gravity (g/cm ³ ): 1.21

Validity period (year): 2

Example 2

1. Prepare raw materials according to the following weight ratio:

Softened water: 180kg;

Phosphoric acid (85% aqueous solution): 150kg;

Urea (nitrogen content is about 46.4%): 54kg;

Catalyst: 0.48kg;

Silica sol (mass fraction of silica is about 20%): 60kg;

Boric acid (content above 99%) 10kg.

Among them, the catalyst is a light yellow-green powder prepared by the Environmental Protection Flame Retardant Technology Center of the School of Materials Science and Technology, Beijing Forestry University. The preparation process is as follows: 0.9 parts of tin chloride, 1.6 parts of copper sulfate, 1.0 parts of sodium chloride, 1.0 parts of ferric chloride, 1.2 parts of aluminum sulfate, 1.1 parts of boric acid and 2.0 parts of zinc chloride are ground and mixed uniformly.

2. The preparation process is as follows:

1) Add phosphoric acid to a reaction kettle equipped with a stirrer, a thermometer and a condenser, stir while heating to raise the temperature to 50°C;

2) Add urea into the reactor, and at the same time continue to stir the mixture of phosphoric acid and urea, so that the material is distributed and heated evenly;

3) Continue heating until the temperature rises to 115°C, slowly and evenly add catalyst to the reaction kettle to make the mixture react; continue heating until the temperature reaches about 130°C, observe the reaction phenomenon while continuing to heat, High, the light green liquid gradually turns into a milky white viscous substance, the foam increases sharply, the temperature rise speed is obviously accelerated, the volume of the material expands rapidly, a large amount of gas is discharged from the condenser tube, and the volume of the reactant in the reactor increases to 2.5% of the original volume When the time is doubled, stop heating and continue stirring. The materials in the reactor continue to react violently by their own heat release, and the temperature continues to rise. When the reaction becomes stable, the temperature will no longer rise.

4) When the temperature drops to about 65°C, add demineralized water and boric acid at a temperature of 40°C to the reaction kettle, and stir evenly;

5) When the temperature is lowered to about 20°C, use sodium hydroxide to adjust the solution (mass concentration 45%) to adjust the pH value between 8.5-9.5, and finally add silica sol to the reaction kettle and stir evenly;

6) Pour the resulting product into a container for storage.

Product technical indicators:

Appearance: Transparent liquid

Solid content (wt%): 42

pH value: 8.5-9.5

Viscosity (coated - 4 cups) (25°C, S): 10.3

Specific gravity (g/cm3): 1.19

Validity period (year): 2

Example 3

1. Prepare raw materials according to the following weight ratio:

Softened water: 100kg;

Phosphoric acid (80% aqueous solution): 65kg;

Urea (nitrogen content is about 46.4%): 38kg;

Catalyst: 0.28kg;

Silica sol (mass fraction of silica is about 30%): 30kg;

Boric acid (more than 99%) 6kg;

Wherein, catalyst is with embodiment 1.

2. The preparation process is the same as in Example 1.

The technical index of the obtained product:

Appearance: Transparent liquid

Solid content (wt%): 46

pH value: 8.5-9.5

Viscosity (coated - 4 cups) (25°C, S): 10.4

Specific gravity (g/cm3): 1.22

Validity period (year): 2

Example 4

1. Prepare raw materials according to the following weight ratio:

Softened water: 70kg;

Phosphoric acid (90% aqueous solution): 50kg;

Urea: (nitrogen content is about 46.4%) 32kg;

Catalyst: 0.25kg;

Silica sol (mass fraction of silica is about 25%): 50kg;

Boric acid (content above 99%) 8kg;

Wherein, catalyst is with embodiment 2.

2. The preparation process is the same as in Example 2.

The technical index of the obtained product:

Appearance: Transparent liquid

Solid content (wt%): 45

pH value: 8.5-9.5

Viscosity (coated - 4 cups) (25°C, S): 10.4

Specific gravity (g/cm ³ ): 1.21

Validity period (year): 2

Experimental example 1

Plywood was prepared by using the flame retardant products of Examples 1-4 of the present invention respectively.

Experimental Materials:

Veneer: Poplar veneer, thickness 1.4-1.5mm, moisture content 7%-9%, format 450×450mm;

Adhesive: commercially available modified urea-formaldehyde resin adhesive (melamine modified, the molar ratio of dosage to urea-formaldehyde resin dosage is 1.1), the performance index of the product is as follows:

2. Specific experimental steps:

1) Glue adjustment: add 15% flour and 1% ammonium chloride to the adhesive by weight, and stir evenly;

2) Apply glue to the veneer, the amount of glue applied is 280g/m ² on both sides;

3) Carry out cold pressing, hot pressing, cooling and edge trimming of the five-layer veneer blanks in sequence. The cold pressing pressure is 1-1.2MPa, the cold pressing time is 30min; the hot pressing pressure is 1.0-1.2MPa, the hot pressing temperature is 120°C, and the hot pressing time is 60s/mm.

4) Prepare the flame retardant of Examples 1-4 of the present invention into an aqueous solution with a solid content of 10 wt%, and dip the plywood for 10 minutes;

5) Use a dehumidification drying box to dry the treated plywood at a drying temperature of 60°C so that the final moisture content reaches 10-12%;

3. Performance testing of plywood

According to GB/T17657-1999 "Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels", the performance of the prepared plywood was tested, and the results are shown in Table 1.

Refer to GB/T2406-93 "Plastic Combustibility Test Method Oxygen Index Method" to measure the oxygen index index of the prepared plywood products. The oxygen index of Class B1 stipulated in GB50222-95 "Code for Fire Protection Design of Building Interior Decoration" is ≥ 48%.

Comparative example 1

Except that the flame retardant of the present invention was not impregnated, other steps were the same as in Experimental Example 1, and the same plywood was prepared as a control.

Comparative example 2

Use commercially available nitrogen-phosphorus water-based flame retardant (CAS No.: 68333-79-9, Shanghai Xinhua Flame Retardant General Factory, degree of polymerization less than 20) to replace the flame retardant of the present invention for impregnation (solid content concentration , immersion time, etc. are the same as in Experimental Example 1), other steps are the same as in Experimental Example 1, and the same plywood is prepared as a control.

The results of Experimental Example 1 and Comparative Examples 1 and 2 are shown in Table 1:

Table 1 Plywood performance test results

The results in Table 1 show that the flame retardant of the present invention not only has remarkable flame retardant effect, but also has obvious formaldehyde elimination effect. The plywood impregnated with the flame retardant of the present invention has an oxygen index of more than 57%, and the formaldehyde emission can be stabilized at E ₀ level (≤0.5mg/L), which is superior to existing products.

Experimental example 2

Poplar wood was treated with the flame retardant products of Examples 1-4 of the present invention respectively.

Poplar: 10 years old, sapwood, dimensional stability and loss resistance test specimen size (radial x chord x axial) 30 x 30 x 5mm, anti-corrosion test specimen size (radial x chord x Axial) 20×20×10mm;

Treat the poplar wood specimens according to the following process:

The flame retardants of Examples 1-4 of the present invention were formulated into aqueous solutions with a solid content of 10 wt%.

Poplar wood specimens were extracted with a mixture of benzene and ethanol (2:1) (V/V) for 12 hours before use, placed in a blast drying oven at 105°C for 12 hours, weighed the absolute dry specimens and Measure its size.

Put the test piece in the beaker filled with the above flame retardant, press the test piece with stones. Put the beaker into a vacuum box and keep it for 0.5 hours at a vacuum degree of 0.02MPa at room temperature; return to normal pressure and keep it for 24 hours. Take out the test piece, wipe the surface clean; put it in a blast drying oven at 105°C for 12 hours, and measure its weight and size.

The anticorrosion test specimens were subjected to white rot fungi and brown rot fungi experiments (placed in the test box under normal conditions for 1 month), and then the weight of the specimens was measured.

Put the treated specimens for dimensional stability and anti-loss experiments into a beaker filled with clean water to ensure that the water surface covers the specimens. Put the beaker into a vacuum dry box with a vacuum degree of 0.02MPa, keep it for 0.5 hours, and keep it at normal pressure for 24 hours, and measure its weight and size. Then put the test piece in a blast drying oven at 105°C for 12 hours, weigh the weight of the dry test piece and measure its size.

Comparative example 3

No flame retardant was used to treat the specimen, and the other steps were the same as in Experimental Example 2.

Comparative example 4

The nitrogen-phosphorus water-based flame retardant of Comparative Example 2 was used to prepare an aqueous solution with a solid content of 10 wt%, and the poplar was treated, and the treatment steps were the same as in Experimental Example 2.

The results of Experimental Example 2 and Comparative Examples 3 and 4 are shown in Table 2:

Table 2 Performance test results of specimens

The results in Table 2 show that the wood treated with the flame retardant of the present invention has shown a dimensional stabilization effect, has good loss resistance, and also has excellent anti-corrosion effect, which is not available in the existing flame retardants. Function.

The results of Experimental Examples 1-2 and Comparative Examples 1-4 show that the flame retardant provided by the present invention not only has an ideal flame retardant effect, but also has obvious dimensional stability and anti-corrosion effects, and is a new type of multifunctional flame retardant. fuel products.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. a wood fire retardant is characterized in that, comprises by weight following raw material:

Phosphoric acid: 20～200 parts;

Urea: 20～100 parts;

Catalyst: 0.1～1.0 part;

Water: 40～250 parts;

Ludox: 10～100 parts;

Boric acid: 1～15 part;

Described catalyst consists of the following composition by weight: 0.8～1.2 part of stannic chloride; 1.5～2.5 parts in copper sulphate; 0.8～1.2 part in sodium chloride; 0.8～1.2 part in iron chloride; 0.8～1.2 part in aluminum sulfate; 1.5～2.5 parts of 0.8～1.2 part of boric acid and zinc chloride.

2. fire retardant according to claim 1 is characterized in that, comprises by weight following raw material:

Phosphoric acid: 50～150 parts;

Urea: 30～60 parts;

Catalyst: 0.2～0.5 part;

Water: 50～200 parts;

Ludox: 20～60 parts;

Boric acid: 5～10 parts.

3. fire retardant according to claim 1 and 2 is characterized in that, described phosphoric acid is that mass percent concentration is 80～90% phosphate aqueous solution.

4. the preparation method of each described fire retardant of claim 1-3 is characterized in that, may further comprise the steps:

(1) in reactor, adds phosphoric acid, stir and heating, make temperature rise to 50～60 ℃;

(2) in described reactor, add urea, stir;

When (3) temperature rises to 90～120 ℃, in described reactor, add catalyst, after temperature rises to 130～140 ℃, stopped heating;

(4) described reactor is cooled to 60～80 ℃, adds entry and boric acid, stir;

When (5) reactor was cooled to 20～30 ℃, adding inorganic base to pH value was 8.5～9.5, adds Ludox again in described reactor, stirred and get final product.

5. preparation method according to claim 4 is characterized in that, described inorganic base is NaOH or potassium hydroxide.

6. preparation method according to claim 5 is characterized in that, described inorganic base is that mass percent concentration is 30～50% the aqueous solution.

7. each described preparation method is characterized in that according to claim 4-6, and the rotating speed of described stirring is 50～70 rev/mins.

8. each described preparation method is characterized in that according to claim 4-6, in the described step (3), and after temperature rises to 130～140 ℃, stopped heating when described reactor internal reaction object amasss 2～3 times that increase to original volume.

9. each described fire retardant of claim 1-3 is as the purposes of timber size stabilizing agent.

10. each described fire retardant of claim 1-3 is as the purposes of timber preservative.