CN115961474A - A glass fiber surface treatment agent and its application in the preparation of PTFE-glass fiber composite filter material - Google Patents

Abstract

A glass fiber surface treating agent relates to the technical field of surface treating agents, and comprises 0.2-0.7% of silane coupling agent, 20-40% of PTFE concentrated dispersion liquid, 0.1-0.5% of penetrating agent, 0.1-5% of amino protective agent, 0.1-5% of defoaming agent and the balance of pure water; by adding the amino protective agent, the amino contained in the coupling agent is protected from being oxidized at high temperature, and the yellowing of cloth caused by the generation of azo substances is avoided; and adding a defoaming agent to quickly eliminate bubbles; the invention also provides a method for preparing the PTFE-glass fiber composite filter material, which adopts a solution soaking dewaxing method to replace the traditional heat treatment and uses the glass fiber surface treating agent to treat the cloth, thereby making up the defects in the original preparation process.

Description

A glass fiber surface treatment agent and its application in the preparation of PTFE-glass fiber composite filter material

technical field

The invention relates to the technical field of surface treatment agents, in particular to a glass fiber surface treatment agent and its application in preparing PTFE-glass fiber composite filter materials.

Background technique

As the current mainstream dust filter bag, glass fiber cloth has the characteristics of smooth surface and small friction coefficient with dust, which is beneficial to the subsequent dust stripping. Its excellent chemical stability can deal with corrosive substances other than high temperature strong alkali and hydrofluoric acid. In addition, the main component of the cloth is silica, which is the most abundant element in the earth's crust. The source of raw materials is wide and the price is low, so glass fiber cloth is considered to be an ideal filter material.

However, glass fiber cloth also has the following disadvantages as a filter material. On the one hand, the fabric has poor folding resistance and wear resistance, and is easy to wear and break during use, which affects the service life of the material; on the other hand, the conventional glass fiber filter material does not Hydrolysis resistance is not enough to deal with high-temperature environments with complex chemical components such as waste incineration boilers and coal-fired power plants.

In order to truly reflect the practicability of glass fiber cloth, it is necessary to carry out surface treatment to enhance the wear resistance and chemical stability of the material. PTFE emulsion is a commonly used resin coating for glass fiber filter cloth, and its molecular chain is in a helical conformation. Protect the internal materials from outside intrusion, and the weather resistance of the glass fiber is significantly enhanced under the protection of the coating. However, the existence of the sizing agent on the surface of the glass fiber greatly increases the difficulty of bonding PTFE, and the sizing agent needs to be removed before the film can be covered. The heat treatment mentioned in the Chinese invention patent with the publication number CN108411633A will cause the sizing agent to oxidize and change color, causing cloth The face turns yellow; and in the Chinese invention patent with publication number CN107010847B, some additives are introduced, such as the improper use of silane coupling agent, which will cause the color of the cloth to deepen, and the products prepared by these methods will affect the color, which cannot satisfy consumers' requirements for the product. Appearance requirements; and surfactants are added to the formula, resulting in a long waiting time for the impregnation process to defoam, and a large number of bubbles are generated, which makes the color and performance of the cloth surface poor. All of the above have caused adverse effects on the appearance and performance of the product It shows that there are still some deficiencies in the surface treatment agent formulation and preparation process of the current PTFE-glass fiber composite filter material, which need to be further improved.

Contents of the invention

Aiming at the deficiencies in the prior art, the utility model provides a glass fiber surface treatment agent and its application in the preparation of PTFE-glass fiber composite filter material, which solves the problem of PTFE-glass fiber in the prior art. There are insufficient problems in the performance of the glass fiber surface treatment agent and the preparation process of the composite filter material.

A glass fiber surface treatment agent, including silane coupling agent 0.2-0.7%, PTFE concentrated dispersion 20-40%, penetrating agent 0.1-0.5%, amino protecting agent 0.1-5% and defoamer 0.1-5%, The balance is pure water.

Preferably, the content of the amino protecting agent is 0.5-3%.

Preferably, the content of the defoamer is 1-4%.

Preferably, the amino protecting agent is one of di-tert-butyl dicarbonate, benzyl chloroformate and p-methoxybenzyl bromide.

Preferably, the defoamer is one of emulsified silicone oil, polydimethylsiloxane and polyoxyethylene polyoxypropanolamine ether.

The present invention also provides a kind of method in preparing PTFE-glass fiber composite filter material, comprises the following steps:

(1) Dewaxing solution is configured in the dewaxing tank, and pure water is added in the cleaning tank;

(2) Soak the original cloth in a dewaxing tank for 2-7 minutes for dewaxing, while keeping the temperature of the dewaxing tank at 50-80°C to obtain a cloth with a wax content lower than 0.3%;

(3) Clean the cloth that has been dewaxed through the cleaning tank;

(4) Put the cleaned cloth into an oven at 120°C to dry for 10 minutes;

(5) Dip the dried cloth into the glass fiber surface treatment agent;

(6) Dry the cloth in an oven at 250° C. for 10 minutes to obtain a finished cloth.

Preferably, the dewaxing solution in step (1) includes a dewaxing agent and pure water, and the dewaxing agent includes 5-15% of a strong base and 3-10% of a penetrating agent.

Preferably, the strong base is sodium hydroxide or potassium hydroxide.

Preferably, in step (3), when using the cleaning tank to clean the cloth, it is necessary to measure the pH value of the cleaning tank every hour.

Compared with the prior art, the present invention has the following beneficial effects:

1. An amino protective agent is added to the glass fiber surface treatment agent, which is used to protect the amino group contained in the coupling agent from being oxidized under high temperature conditions, and to avoid the formation of azo substances that cause yellowing of the fabric.

2. The glass fiber surface treatment agent is added with a defoamer. On the one hand, it can help the emulsion in the dipping tank to defoam quickly, shorten the standing time, and improve production efficiency. On the other hand, it can reduce the bubbles generated during the production process, which helps The emulsion is evenly distributed on the surface of the glass fiber cloth, improving and improving the appearance and performance of the product.

3. And the solid content in the glass fiber surface treatment agent in the present invention is relatively low, the solid content is 15-35%.

4. The traditional heat treatment is replaced by the solution soaking dewaxing method, which avoids the yellowing of the fabric caused by the oxidation of the sizing agent during the dewaxing process, and effectively improves the appearance of the product;

5. At the same time, when the measured pH of the pure water in the cleaning tank reaches above 10, the pure water is divided into two parts, one part is diluted and reused, and the other part can be used as a supplement to the dewaxing tank after adding an appropriate amount of dewaxing agent Liquid, improve the utilization rate of raw materials, reduce waste liquid treatment costs, save production costs, and avoid environmental pollution;

Other advantages, objectives and features of the present invention will partly be embodied through the following descriptions, and partly will be understood by those skilled in the art through the study and practice of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and functions achieved by the present invention clearer and easier to understand, the present invention will be further elaborated below in conjunction with specific embodiments:

Example 1

To prepare the glass fiber surface treatment agent, the coupling agent is pre-hydrolyzed first, acetic acid and pure water are added in the pre-hydrolysis process, and then the mixed acid solution is slowly added to the coupling agent. Take 0.2% of the pre-hydrolyzed product and add a certain amount of pure water, then sequentially add 40% PTFE concentrated dispersion, 0.1% penetrant, 1% emulsified silicone oil, 0.5% di-tert-butyl dicarbonate and a certain amount of pure water, stir evenly so that the solid content of the final emulsion is 18%. Run the E-type glass raw cloth with a width of 1650mm at a linear speed of 2m/s, and stay in the dewaxing tank for 4min, wherein the mass fraction of sodium hydroxide in the dewaxing solution is 8%, and the mass fraction of penetrant is 5% , the temperature of the dewaxing tank is 70°C, pass through the cleaning tank, take samples every 1h to test the pH value of the cleaning tank, then dry the cloth in an oven at 120°C for 10 minutes, and impregnate the dewaxed cloth in the previously prepared glass fiber surface treatment agent Finally, the cloth was dried in an oven at 250°C for 10 minutes to obtain the finished cloth.

Example 2

To prepare the glass fiber surface treatment agent, the coupling agent is pre-hydrolyzed first, acetic acid and pure water are added in the pre-hydrolysis process, and then the mixed acid solution is slowly added to the coupling agent. Take 0.5% of the pre-hydrolyzed product and add a certain amount of pure water, then add 30% PTFE concentrated dispersion, 0.3% penetrant, 1.5% polydimethylsiloxane, 2% benzyl chloroformate and a certain amount of pure water. Quantity of pure water, stirred evenly so that the solid content of the final emulsion is 22%. Run the E-type glass raw cloth with a width of 1650mm at a linear speed of 2m/s, and stay in the dewaxing tank for 7 minutes, wherein the mass fraction of sodium hydroxide in the dewaxing solution is 5%, and the mass fraction of penetrating agent is 3%. , the temperature of the dewaxing tank is 80°C, pass through the cleaning tank, take samples every 1h to test the pH value of the cleaning tank, then dry the cloth in an oven at 120°C for 10 minutes, and impregnate the dewaxed cloth in the previously prepared glass fiber surface treatment agent Finally, the cloth was dried in an oven at 250°C for 10 minutes to obtain the finished cloth.

Example 3

To prepare the glass fiber surface treatment agent, the coupling agent is pre-hydrolyzed first, acetic acid and pure water are added in the pre-hydrolysis process, and then the mixed acid solution is slowly added to the coupling agent. Take 0.7% of the pre-hydrolyzed product and add a certain amount of pure water, then add 20% PTFE concentrated dispersion, 0.5% penetrant, 3% emulsified silicone oil, 2.5% p-methoxybenzyl bromide and a certain amount of Pure water, stirred evenly so that the solid content of the final emulsion is 28%. Run the E-type glass raw cloth with a width of 1650mm at a linear speed of 2m/s, soak it in a dewaxing tank for 2min, wherein the mass fraction of sodium hydroxide in the dewaxing solution is 15%, and the mass fraction of penetrating agent is 10% , the temperature of the dewaxing tank is 50°C, pass through the cleaning tank, take samples every 1h to test the pH value of the cleaning tank, then dry the cloth in an oven at 120°C for 10 minutes, and impregnate the dewaxed cloth in the previously prepared glass fiber surface treatment agent Finally, the cloth was dried in an oven at 250°C for 10 minutes to obtain the finished cloth.

Example 4

To prepare the glass fiber surface treatment agent, the coupling agent is pre-hydrolyzed first, acetic acid and pure water are added in the pre-hydrolysis process, and then the mixed acid solution is slowly added to the coupling agent. Take 0.4% of the pre-hydrolyzed product and add a certain amount of pure water, then add 25% PTFE concentrated dispersion, 0.2% penetrant, 4% polyoxyethylene polyoxypropanolamine ether, 3% di-tert-dicarbonate Butyl ester and a certain amount of pure water were stirred evenly so that the solid content of the final emulsion was 23%. Run the E-type glass raw cloth with a width of 1650mm at a linear speed of 2m/s, and stay in the dewaxing tank for 3 minutes, wherein the mass fraction of potassium hydroxide in the dewaxing solution is 10%, and the mass fraction of penetrating agent is 7% , the temperature of the dewaxing tank is 60°C, pass through the cleaning tank, take samples every 1h to test the pH value of the cleaning tank, then dry the cloth in an oven at 120°C for 10 minutes, and impregnate the dewaxed cloth in the previously configured glass fiber surface treatment agent Finally, the cloth was dried in an oven at 250°C for 10 minutes to obtain the finished cloth.

Comparative example 1

In Example 1, no amino-protecting agent di-tert-butyl dicarbonate was added, pure water of equal quality was added, and the rest of the conditions were the same.

Comparative example 2

In Example 2, no antifoaming agent polydimethylsiloxane was added, pure water of equal quality was added, and the surface treatment agent was prepared and left to defoam for 5 hours. During the dipping process, dense bubbles were found on both sides of the glass fiber cloth.

Comparative example 3

The dewaxing method in Example 3 was changed to heat treatment, and other conditions were the same, and the glass fiber cloth turned yellow after dewaxing.

Comparative example 4

The dewaxing solution in Example 4 was changed to pure water, and other conditions were the same.

The appearance performance test results of Examples and Comparative Examples are in Table 1. The industry requires that the gram weight be between 760-820g/m2, the hardness be lower than 10, the oil content be between 9%-13%, and the tensile strength be greater than 2400N/25mm. Aging resistance greater than 80%.

Table 1 Finished fabric appearance and performance test results

The test standards for the above tests are:

Weight test: GB/T 9914.3 (ISO 3374)

Stiffness test: ASTM D4032-08(2012)

Oil content test: GB/T 9914.2 (ISO 1887)

Tensile strength test: GB/T 7689.5 (ISO 4606)

Aging resistance test: place the glass fiber cloth in an oven at 200°C for 30 days, and test the retention rate of warp and weft tensile strength.

Solid content test: Take a certain amount of PTFE emulsion and dry it in an oven at 100°C to constant weight, and calculate the ratio of the remaining solid mass to the initial mass.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (9)

1. A glass fiber surface treatment agent, characterized in that it comprises silane coupling agent 0.2-0.7%, PTFE concentrated dispersion 20-40%, penetrating agent 0.1-0.5%, amino protecting agent 0.1-5% and defoaming agent Agent 0.1-5%, the balance is pure water. 2. A glass fiber surface treatment agent according to claim 1, characterized in that the content of said amino protecting agent is 0.5-3%. 3. A glass fiber surface treatment agent according to claim 1, characterized in that the content of the defoamer is 1-4%. 4. a kind of glass fiber surface treatment agent according to claim 1 or 2, is characterized in that, described amino protecting agent is di-tert-butyl dicarbonate, benzyl chloroformate and p-methoxybenzyl bromide A sort of. 5. A kind of glass fiber surface treatment agent according to claim 1 or 2, is characterized in that, described defoamer is emulsified silicone oil, polydimethylsiloxane and polyoxyethylene polyoxypropanolamine ether kind of. 6. A method for preparing PTFE-glass fiber composite filter material, is characterized in that, comprises the following steps: (1) Dewaxing solution is configured in the dewaxing tank, and pure water is added in the cleaning tank; (2) Soak the original cloth in a dewaxing tank for 2-7 minutes for dewaxing, while keeping the temperature of the dewaxing tank at 50-80°C to obtain a cloth with a wax content lower than 0.3%; (3) Clean the cloth that has been dewaxed through the cleaning tank; (4) Put the cleaned cloth into an oven at 120°C to dry for 10 minutes; (5) the finished cloth is immersed in the glass fiber surface treatment agent as claimed in claim 1; (6) Dry the cloth in an oven at 250° C. for 10 minutes to obtain a finished cloth. 7. according to a kind of method in the preparation PTFE-glass fiber composite filter material in claim 7, it is characterized in that, the dewaxing solution in the step (1) comprises dewaxing agent and pure water, and described dewaxing agent comprises strong Alkali 5-15% and penetrant 3-10%. 8. according to the method in a kind of preparation PTFE-glass fiber composite filter material in claim 8, it is characterized in that, described strong base is sodium hydroxide or potassium hydroxide. 9. according to a kind of method in the preparation PTFE-glass fiber composite filter material in claim 7, it is characterized in that, in step (3), when using cleaning tank to clean cloth, need every 1 hour to cleaning tank PH value is measured.