CN110549443A

CN110549443A - Multifunctional wood protective agent prepared from multi-element composite nano silica sol and preparation method thereof

Info

Publication number: CN110549443A
Application number: CN201910819060.9A
Authority: CN
Inventors: 余丽萍; 李利芬; 吴志刚; 田美芬
Original assignee: Guizhou University
Current assignee: Guizhou University
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2019-12-10
Anticipated expiration: 2039-08-30
Also published as: CN110549443B

Abstract

The invention relates to the technical field of wood protective agents, in particular to a multifunctional wood protective agent prepared from multi-element composite nano silica sol and a preparation method thereof. The invention uses cheap alkaline silica sol hydrolyzed by simple substance silicon and a plurality of medicaments to compound, prepares the multifunctional wood protective agent which can simultaneously endow wood with a plurality of effects such as flame retardance, corrosion resistance, mildew resistance, stable size and the like, and the protective agent selects special alkaline silica sol and a specific amount of boride and nitrogen and phosphorus compounds, thereby achieving multi-component compounding, bringing multiple effects, simultaneously enabling the sol system to be fully kept stable, not causing rapid gelation, and enabling people to have sufficient time for processing wood. The agent has wide raw material source, low price and simple preparation, and can be used for flame-retardant and anti-corrosion treatment of wood structure buildings.

Description

Multifunctional wood protective agent prepared from multi-element composite nano silica sol and preparation method thereof

Technical Field

The invention relates to the technical field of wood protective agents, in particular to a multifunctional wood protective agent prepared from multi-element composite nano silica sol and a preparation method thereof.

Background

Because China takes natural forest protection measures, the artificial fast-growing forest becomes a main timber forest, but the fast-growing wood has the defects of loose material, low density, low strength, corrosion resistance, flammability and the like, and the functional improvement of the artificial fast-growing forest wood is one of effective ways for relieving the shortage of wood resources and improving the industrial structure of wood. However, the conventional modifier with single function can not meet the requirements of people, the development of the modifier integrating multiple functions of corrosion prevention, mildew prevention, flame retardance, water resistance and the like is the main research direction of wood modification at present, and a multi-effect protective agent becomes the key point of wood modification research.

some medicaments have been the research focus of wood flame retardants due to the advantages of no toxicity, low price, good flame retardance, small influence on the mechanical properties of wood, simple treatment process and the like. For example, nitrogen and phosphorus systems mainly have good flame retardant effect on wood through the mechanisms of decomposing non-combustible gas by heating, reducing the thermal decomposition temperature, improving the char yield and the like. The boride is flame retardant through the mechanism that molten substances cover the surface of the wood to isolate oxygen and promote carbon formation, and has the functions of corrosion prevention, insect prevention and the like. However, the fatal defect of the agents is that the agents are easy to precipitate in a humid environment so as to lose the protection effect on wood.

researchers find that inorganic nano materials can be used for carrying out composite modification on wood base materials according to the facts that wood is slowly permeated by silicic acid for millions of years in nature and naturally mineralized to form silicified wood and based on a binary synergetic nano interface material technology. The nano silica sol has special surface effect, quantum size effect and small size effect, so that the interface effect and the compatibility between the medicine and wood can be enhanced. The wood is less destructive, and the excellent environmental characteristics of the wood are kept to the maximum extent.

At present, the main common researches for the nano-silica sol modification of wood are metal alkoxides M (OR) n (M is Si, Ti, B, Zn, Fe, etc., R is alkyl, and n is oxidation number), such as Tetraethoxysilane (TEOS), trimethoxy silane (MTMOS), n-butyl titanate (TBOT), tetraisopropyl titanate (TPT), etc. Although the wood has certain effect on improving the performance of various aspects of the wood, the wood has the biggest defects of high price, complex treatment process and no process and cost advantages in industrial production. The silica sol is compounded with other agents, but only one or two agents are compounded, the function is only single flame retardance or corrosion resistance, and the like, when the silica sol is compounded with a plurality of agents, the silica sol can be quickly gelled, and wood cannot be treated by the silica sol, so the silica sol on the market basically has a single function.

therefore, it is urgent to find a multifunctional wood protective agent which does not gel rapidly, has sufficient time for treating wood, and can simultaneously provide the functions of flame retardance, corrosion resistance, mildew resistance, dimensional stability and the like to the wood.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides a multifunctional wood protective agent prepared from multi-element composite nano silica sol and a preparation method thereof, and the preparation method specifically comprises the following steps:

A preparation method of a multifunctional wood protective agent prepared from multi-element composite nano silica sol comprises the following steps:

(1) Preparing raw materials: taking alkaline nano silica sol, borax, boric acid and nitrogen-phosphorus compounds;

(2) adding alkaline nano silica sol into a container provided with a stirrer, and adding boric acid and borax while stirring until the solution is completely dissolved;

(3) After the nitrogen and phosphorus compounds are completely dissolved, the nitrogen and phosphorus compounds are added and stirred continuously until the nitrogen and phosphorus compounds are completely dissolved.

Preferably, the weight parts of the components are as follows: 84-94 parts of alkaline nano silica sol, 1-4 parts of borax, 1-5 parts of boric acid, 0-2 parts of phosphoric acid and 2-8 parts of nitrogen and phosphorus compounds.

Preferably, the alkaline nano silica sol has a concentration of 10-30% and a particle size of less than 20 nm. The silica sol is prepared by a simple substance silicon hydrolysis method, has wide raw material sources, low price, environmental protection and better permeability to wood, and can well fix other compound agents in the wood by utilizing a gel system, thereby playing a role in durably protecting the wood.

preferably, the nitrogen and phosphorus compound is ammonium polyphosphate. Further preferably, the weight parts of the components are as follows: 84-92 parts of alkaline nano silica sol, 1-4 parts of borax, 1-4 parts of boric acid, 0.5-2 parts of phosphoric acid and 3-8 parts of ammonium polyphosphate. The borax and the boric acid can play a role in flame retardance and corrosion and mildew resistance; the ammonium polyphosphate can play a role in flame retardance; the phosphoric acid can play a role in delaying the gelation of a silica sol system and also play a certain flame retardant role, the composition of the phosphoric acid and the phosphoric acid has a synergistic effect, and the alkaline silica sol can improve the dimensional stability of the wood and increase the anti-losing performance of other medicaments.

Preferably, the nitrogen and phosphorus compound is ammonium dihydrogen phosphate. Further preferably, the weight parts of the components are as follows: 88-94 parts of alkaline nano silica sol, 1-3 parts of borax, 1.5-5 parts of boric acid, 0-2 parts of phosphoric acid and 2-5 parts of ammonium dihydrogen phosphate. The borax and the boric acid can play a role in flame retardance and corrosion and mildew resistance, the ammonium dihydrogen phosphate can play a role in flame retardance, the phosphoric acid can play a role in delaying the gelation of a silica sol system and also can play a certain role in flame retardance, the composition of the borax and the boric acid has a synergistic effect, the silica sol can improve the dimensional stability of wood, and the anti-leaching performance of other agents is improved.

Compared with the prior art, the invention has the technical effects that:

1. the multifunctional wood protective agent is prepared by compounding cheap alkaline silica sol hydrolyzed by simple substance silicon and various agents, and can endow wood with various functions of flame retardance, corrosion resistance, mildew resistance, stable size and the like.

2. The invention uses alkaline silica sol and various agents to carry out compounding, achieves multi-component compounding, brings multiple effects, simultaneously enables a sol system to be fully stable, does not cause rapid gelation, and can have sufficient time for treating wood.

3. the invention uses alkaline silica sol and various medicaments to compound, achieves multi-component compounding, brings multiple effects, simultaneously enables the sol to have moderate gelation time, the gelation time is too fast to facilitate wood treatment, the gelation time is too slow to fix the medicaments in the wood, the protective agent of the invention can be solidified in proper time, and the wood can smoothly absorb the protective agent and fix the medicaments in the wood.

4. The invention fixes other agents in the wood by using the alkaline silica sol, the agents cannot easily flow out in a rainy or humid environment, the long-lasting protection effect is realized on the wood, and all components are environment-friendly and nontoxic, and the environment cannot be polluted.

5. The invention uses alkaline silica sol and various medicaments for compounding, so that the oxygen index of wood is improved by 58-140%, the corrosion resistance is improved by 70-96%, the mould control efficiency is improved by 50-100%, the dimensional stability is improved by 25-49%, and the water absorption is reduced by 25-70%.

Detailed Description

The technical solution of the present invention is further defined below with reference to the specific embodiments, but the scope of the claims is not limited to the description.

Example 1

(1) Preparing raw materials: taking 336g of alkaline silica sol with the concentration of 10 percent and the particle size of less than 20nm, 16g of borax, 16g of boric acid, 8g of phosphoric acid and 32g of ammonium polyphosphate;

(2) Adding alkaline silica sol into a container provided with a stirrer, and adding boric acid and borax while stirring until the boric acid and borax are completely dissolved;

(3) adding phosphoric acid, stirring uniformly, adding ammonium polyphosphate, and continuously stirring until the ammonium polyphosphate is completely dissolved.

example 2

(1) Preparing raw materials: taking 360g of alkaline silica sol with the concentration of 20 percent and the particle size of less than 20nm, 8g of borax, 8g of boric acid, 4g of phosphoric acid and 24g of ammonium polyphosphate;

Example 3

(1) preparing raw materials: taking 380g of alkaline silica sol with the concentration of 30% and the particle size of less than 20nm, 4g of borax, 4g of boric acid, 2g of phosphoric acid and 12g of ammonium polyphosphate;

Example 4

(1) Preparing raw materials: 364g of alkaline silica sol with the concentration of 20 percent and the particle size of less than 20nm, 8g of borax, 12g of boric acid, 4g of phosphoric acid and 14g of ammonium dihydrogen phosphate are taken;

(3) adding phosphoric acid, stirring uniformly, adding ammonium dihydrogen phosphate, and continuously stirring until the ammonium dihydrogen phosphate is completely dissolved.

Example 5

(1) preparing raw materials: 376g of alkaline silica sol with the concentration of 10 percent and the particle size of less than 20nm, 4g of borax, 6g of boric acid, 0g of phosphoric acid and 8g of ammonium dihydrogen phosphate are taken;

(3) After stirring evenly, adding ammonium dihydrogen phosphate and continuing stirring until the ammonium dihydrogen phosphate is completely dissolved.

Example 6

(1) Preparing raw materials: taking 352g of alkaline silica sol with the concentration of 30% and the particle size of less than 20nm, 12g of borax, 20g of boric acid, 4g of phosphoric acid and 20g of ammonium dihydrogen phosphate;

Comparative example 1

(1) Preparing raw materials: taking 352g of alkaline silica sol with the concentration of 20 percent and the particle size of less than 20nm, 20g of borax, 20g of boric acid and 36g of ammonium polyphosphate;

(2) Adding alkaline silica sol into a container provided with a stirrer, adding boric acid and borax while stirring, and continuously stirring;

(3) Ammonium polyphosphate is added to continue stirring, gelation is rapidly carried out in the stirring process, and the experiment can not be continued.

Comparative example 2

(1) Preparing raw materials: taking 352g of alkaline silica sol with the concentration of 20 percent and the particle size of less than 20nm, 2g of borax, 2g of boric acid, 1g of phosphoric acid and 4g of ammonium polyphosphate;

(3) Adding phosphoric acid, stirring uniformly, adding ammonium polyphosphate, and continuously stirring until the ammonium polyphosphate is completely dissolved, wherein the gel time is long.

Comparative example 3

(4) Preparing raw materials: taking 352g of alkaline silica sol with the concentration of 20 percent and the particle size of less than 20nm, 16g of borax, 24g of boric acid and 24g of ammonium dihydrogen phosphate;

(5) adding alkaline silica sol into a container provided with a stirrer, adding boric acid and borax while stirring, and continuously stirring;

(6) ammonium dihydrogen phosphate is added to continue stirring, the gel is rapidly formed in the stirring process, and the experiment cannot be continued.

Comparative example 4

(4) Preparing raw materials: taking 352g of alkaline silica sol with the concentration of 20 percent and the particle size of less than 20nm, 0.8g of borax, 2g of boric acid, 1g of phosphoric acid and 4g of ammonium dihydrogen phosphate;

(5) Adding alkaline silica sol into a container provided with a stirrer, and adding boric acid and borax while stirring until the boric acid and borax are completely dissolved;

(6) Adding phosphoric acid, stirring uniformly, adding ammonium dihydrogen phosphate, and continuously stirring until the ammonium dihydrogen phosphate is completely dissolved, wherein the gel time is long.

Comparative example 5

The procedure was carried out as in example 1 of patent CN 201010558421.8.

the gel times of the examples and comparative examples were compared:

TABLE 1 gel time for each example and comparative example

	gel time
		example 1	12.5h
Example 2	8.5h
		Example 3	9h
Example 4	10.5h
		Example 5	28h
Example 6	15h
		comparative example 1	——
Comparative example 2	＞336h
		Comparative example 3	——
Comparative example 4	＞336h
		Comparative example 5	6h

And (3) performance detection: the wood was treated using each of the examples and comparative examples, and then measured for flame retardancy, corrosion resistance, mold resistance, wet-shrinkage-wet-expansion property, and moisture absorption property after the treatment.

1. the wood treatment method comprises the following steps:

(1) numbering, classifying and weighing the wood blocks.

(2) Putting the wood into a vacuum pressurizing device, firstly pumping the vacuum degree in the device to 0.085-0.095MPa by using a vacuum pump, and keeping the vacuum degree for 30-60 min.

(3) Sucking the prepared sol system into a vacuum pressurizing tank in a vacuum state, pressurizing to 0.6-2.0MPa, keeping for 30-180min, and soaking the sol system into the wood.

(3) And after the impregnation is finished, cleaning the surface of the wood. And then putting the wood into an electric heating forced air drying oven to be dried until the mass is not changed (putting the sample wood block into the oven, drying for 6 hours at 60 ℃, then drying for 2 hours at 103 ℃, taking out and weighing until the difference between the two masses is not large, namely the sample wood block is considered to be completely dried), adjusting for 14 days in a constant temperature and humidity box with the relative humidity of 60 percent at 25 ℃, and carrying out performance detection.

2. The raw material sources are as follows: the experimental wood is from Pinus massoniana grown in Yangtze county of Guizhou province, the width of the annual ring is moderate, and the sapwood (Pinus massoniana lamb) which is not obviously discolored is selected as the material of the sample, and the specification and the application of the sample are as follows:

TABLE 2 sample Specifications

sample specification	use of test samples
		5mm×10mm×120mm	Oxygen index test
20mm×5mm×50mm	Mildew resistance test
		20mm×20mm×20mm	dimensional stability and Water absorption
20mm×20mm×10mm	Corrosion protection and corrosion protection test after loss

3. all indexes followed by the experiment are international or forestry standard indexes, and the indexes are as follows:

(1) Flame retardancy: the determination is carried out according to GB/T2406.2-2009 flame behavior determination by oxygen index method part 2, room temperature test.

(2) Corrosion resistance: the determination is carried out according to LY/T1283 and 2011 laboratory test method for toxicity of wood preservatives to rot fungi.

(3) Mildew resistance: the determination is carried out according to GB/T18261-2013 test method for preventing and controlling wood mildew and blue-turning bacteria by using the mildew preventive.

(4) Dry shrinkage and wet swelling property: the measurement was carried out according to the method for measuring the dry shrinkage of wood and the method for measuring the wet swelling of wood according to GB/T1932-2009.

(5) water absorption: the determination is carried out according to GB/T1934.1-2009 test method for water absorption of wood.

4. Results of the experiment

4.1 flame retardancy:

A wood block with the specification of 5mm multiplied by 10mm multiplied by 120mm is placed on an intelligent oxygen limiting index analyzer to be burnt and tested for limiting Oxygen Index (OI), OI represents the volume fraction concentration of oxygen when an object just supports burning in a mixed gas of oxygen and nitrogen, the higher the OI is, the better the flame retardant property is, and the test results are as follows:

TABLE 3 limiting oxygen index test results

4.2 Corrosion resistance

sterilizing wood blocks with the specification of 20mm multiplied by 10mm, putting the wood blocks into a culture bottle full of wood rot fungi, putting the wood blocks into a constant-temperature constant-humidity incubator with the temperature of 25 ℃ and the relative humidity of 85% to be infected by the wood rot fungi for 12 weeks, taking out the wood blocks, measuring and calculating the mass loss rate of the wood blocks after being infected by white rot fungi, namely Coriolus Versicolor (CV) and brown rot fungi, namely plenopsis densicola (GT), wherein the smaller the mass loss rate is, the better the corrosion resistance of the sample is, and the results are as follows:

Table 4 corrosion resistance test results

4.3 mold resistance

Sterilizing wood blocks with the specification of 20mm multiplied by 5mm multiplied by 50mm, putting the wood blocks into a culture dish full of mildew, putting the wood blocks into a constant-temperature constant-humidity incubator with the temperature of 25 ℃ and the relative humidity of 85%, culturing for 4 weeks, taking out the wood blocks, measuring the infected areas of the wood blocks by aspergillus niger and trichoderma viride, determining the damage value and the prevention effect of a sample, wherein the smaller the damage value is, the higher the prevention effect is, the better the mildew prevention effect is, and the following results are obtained:

TABLE 5 results of the mildew resistance test

4.4 dimensional stability

The test of the dry shrinkage and the wet swelling of the sample wood with the specification of 20mm multiplied by 20mm is carried out according to the national standard, the smaller the dry shrinkage and the wet swelling, the better the dimensional stability of the sample, and the results are as follows:

TABLE 6 Dry shrinkage and Wet swell test results

4.5 Water absorption

the water absorption of the sample wood block with the specification of 20mm multiplied by 20mm is measured according to the international requirement. The results are as follows:

Table 7 water absorption test results

the comparison of the data shows that the wood protective agent disclosed by the invention achieves multi-component compounding, brings multiple effects, enables the gel to be fully kept stable, does not cause rapid gel, has sufficient time for treating wood with the wood protective agent disclosed by the invention, improves the oxygen index of the wood by 58% -140%, improves the corrosion resistance by 70% -96%, improves the mould control efficiency by 50% -100%, improves the dimensional stability by 25% -49%, and reduces the water absorption by 25% -70%.

Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solution of the present invention is not limited to the above-described embodiments, and many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.

Claims

1. a preparation method of a multifunctional wood protective agent prepared from multi-element composite nano silica sol is characterized by comprising the following steps:

2. The preparation method of the multifunctional wood protectant prepared from the multi-element composite nano silica sol according to claim 1, wherein the weight parts of the components are as follows: 84-94 parts of alkaline nano silica sol, 1-4 parts of borax, 1-5 parts of boric acid, 0-2 parts of phosphoric acid and 2-8 parts of nitrogen and phosphorus compounds.

3. The method for preparing the multifunctional wood protectant from the multi-element composite nano silica sol according to claim 2, wherein the alkaline nano silica sol has a concentration of 10-30% and a particle size of less than 20 nm.

4. the method for preparing the multifunctional wood protectant by using the multi-element composite nano silica sol according to claim 3, wherein the nitrogen phosphorus compound is ammonium polyphosphate.

5. the preparation method of the multifunctional wood protectant prepared from the multi-element composite nano silica sol according to claim 4, wherein the weight parts of the components are as follows: 84-92 parts of alkaline nano silica sol, 1-4 parts of borax, 1-4 parts of boric acid, 0.5-2 parts of phosphoric acid and 3-8 parts of ammonium polyphosphate.

6. The method for preparing the multifunctional wood protectant by using the multi-element composite nano silica sol according to claim 3, wherein the nitrogen and phosphorus compound is ammonium dihydrogen phosphate.

7. the preparation method of the multifunctional wood protectant prepared from the multi-element composite nano silica sol according to claim 6, wherein the weight parts of the components are as follows: 88-94 parts of alkaline nano silica sol, 1-3 parts of borax, 1.5-5 parts of boric acid, 0-2 parts of phosphoric acid and 2-5 parts of ammonium dihydrogen phosphate.

8. The multifunctional wood protective agent prepared from the multi-element composite nano silica sol prepared by the preparation method of the multifunctional wood protective agent prepared from the multi-element composite nano silica sol as claimed in claims 1-7.