High-strength intumescent sealing tape as well as preparation method and application thereof

Abstract

The invention provides a high-strength expansive type sealing tape as well as a preparation method and application thereof. The high-strength expansive type sealing tape is prepared from a coated material and a coating layer coated on the surface of the coated material, the coated material is a non-woven fabric; the coating layer comprises the following components in parts by weight: 2-5 parts of modified sodium polyacrylate resin, 0.8-1.5 parts of benzotriazole, 5-15 parts of a humectant, 30-50 parts of a filler, 10-15 parts of a binder, 0.02-0.1 part of a preservative and 20-40 parts of water.The high-strength expansive type sealing tape has a good sealing effect and tear resistance in different pipelines, has good expansive performance, and can be used for sealing the pipelines. And the thread is easier to wind and fit, the use is simple, the unused thread can be reused after being soaked in water, and the sealing effect of the product is not influenced.

Description

Technical Field

[0001] The invention relates to the technical field of sealing tapes, and in particular to a high-strength expansion type sealing tape and a preparation method and application thereof. Background Art

[0002] As an indispensable component of industrial, construction and civil facilities, the sealing performance of pipeline connections is directly related to the safety, stability and service life of the system. Whether it is petrochemical pipelines, water supply and drainage systems, or gas transmission networks, the selection of sealing materials has always been one of the core technologies to ensure leak-free operation. Although traditional sealing materials (such as polytetrafluoroethylene raw tape, rubber sealing rings, anaerobic adhesives, etc.) perform well in specific scenarios, they generally have problems such as rapid performance degradation, inconvenient construction, and non-reusability under complex working conditions (such as high temperature and high pressure, chemical corrosion, and dynamic vibration). In recent years, with the development of industrial equipment towards lightweight and high integration, as well as increasingly stringent environmental protection regulations, the market demand for new sealing materials that are both high-strength, aging-resistant, easy to construct, and sustainable has become more urgent.

[0003] Commonly used sealing materials in the prior art include polytetrafluoroethylene raw tape, rubber sealing ring, anaerobic adhesive, and expansion type sealing material. Among them, polytetrafluoroethylene raw tape is one of the most widely used thread sealing materials. Its advantages are strong chemical inertness, high temperature resistance (-180℃ to 260℃) and low friction coefficient, but it cannot be reused. Once disassembled after installation, the material loses its sealing ability due to plastic deformation and needs to be completely replaced, resulting in waste of resources. It is easy to crack in extremely low temperature environments, and is easily scratched by the sharp edges of threads when thin layers are wound. Multiple layers of winding are required to make up for the lack of strength. It cannot adapt to the gap changes caused by temperature or pressure fluctuations, and the long-term sealing reliability is insufficient. Rubber seals fill the gap through elastic deformation and are suitable for static sealing scenarios, but their defects are poor aging resistance, limited chemical compatibility, large differences in tolerance to oils, acid and alkali media, incorrect selection can easily lead to swelling failure, high installation accuracy requirements, and precise matching of groove dimensions. Improper installation can easily lead to distortion or extrusion damage. Anaerobic adhesive is a single-component liquid sealant. It is difficult to disassemble and repair after curing. Forced disassembly can easily damage the thread surface. A clean and dry surface is required, and the curing time is greatly affected by temperature and gap. In recent years, materials such as water-swellable rubber (WSR) have achieved adaptive sealing by swelling with water absorption. However, the existing technology has the following bottlenecks: the expansion rate is inconsistent with the mechanical properties. Although highly absorbent resins (such as sodium polyacrylate) have a high expansion ratio, they have low mechanical strength and are easily powdered under mechanical stress; and the addition of reinforcing fillers (such as carbon black) will inhibit water absorption. In a long-term hot and humid environment, the material is prone to hydrolysis or oxidative degradation, resulting in a decline in expansion capacity, weak adhesion to the surface of metal or plastic pipes, and easy to fall off due to vibration or pressure fluctuations.

[0004] In summary, developing a sealing tape with good sealing performance, strong anti-tearing ability and reusable is an urgent problem to be solved in the present invention. Summary of the Invention

[0005] Object of the Invention:

[0006] In view of the deficiencies in the prior art, the present invention provides a high-strength expandable sealing tape, its preparation method and application. The high-strength expandable sealing tape of the present invention has good sealing effect and anti-tearing ability in different pipelines, has good expansion performance, is easier to wind and fit the thread, is simple to use, and can be reused after being immersed in water if not used up, without affecting the sealing effect of the product.

[0007] Technical Solution of the Invention:

[0008] The present invention provides a high-strength expandable sealing tape, which is characterized in that it comprises a material to be coated and a coating layer coated on its surface; the material to be coated is non-woven fabric; the components of the coating layer are calculated by weight and include: 2-5 parts of modified sodium polyacrylate resin, 0.8-1.5 parts of benzotriazole, 5-15 parts of humectant, 30-50 parts of filler, 10-15 parts of binder, 0.02-0.1 part of preservative, and 20-40 parts of water.

[0009] Further, the non-woven fabric is polyester fiber non-woven fabric or glass fiber non-woven fabric, and the gram weight is 80-150 g / m 2 。

[0010] Further, the thickness of the coating layer is 0.5-2 mm, and the coating amount is 200-500 g / m 2 。

[0011] Further, the preparation of the coating layer includes the following steps:

[0012] Step 1: Add the binder to water, stir and dissolve it, then add benzotriazole, humectant, and preservative, and stir evenly to obtain a mixed auxiliary material;

[0013] Step 2: Slowly add the filler to the mixed auxiliary material prepared in Step 1, and mix at a stirring speed of 300-450 revolutions per minute at 100-120 °C for 10-15 minutes to obtain a mixture;

[0014] Step 3: Finally, add the modified sodium polyacrylate resin to the mixture prepared in Step 2, and mix at a stirring speed of 300-450 revolutions per minute at 100-120 °C for 2-5 minutes to obtain the coating layer.

[0015] Further, the modified sodium polyacrylate resin is prepared by reacting hydroxyethyl acrylate, attapulgite, acrylic acid, ammonium bicarbonate, and ethylene glycol diglycidyl ether.

[0016] The present invention provides a method for preparing a high-strength expandable sealing tape, which is characterized by comprising the following steps:

[0017] Step 1: Dilute with water in the coating layer, uniformly coat the coating layer on the surface of the non-woven fabric, and control the coating thickness;

[0018] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60-80 °C, and then cut it into strips with a width of 10-50 mm and a length of 5-20 m per roll to obtain the high-strength expandable sealing tape.

[0019] Furthermore, in Step 1, the mass ratio of water to the coating layer is 1-1.5:1; the moisture content of the coated non-woven fabric after drying in Step 2 is 1-5%.

[0020] The present invention provides an application of a high-strength expandable sealing tape, which is characterized in that the high-strength expandable sealing tape is applied to the sealing of pipe threaded connections.

[0021] Furthermore, the using method of the high-strength expandable sealing tape includes the following steps: Soak the high-strength expandable sealing tape in water to activate it, and then wind it around the threaded part of the pipe, with 2-4 layers of winding.

[0022] Furthermore, a pre-tightening force of 5-15 N is applied when winding the high-strength expandable sealing tape.

[0023] Further, the moisturizer is one or a mixture of glycerol, propylene glycol, sorbitol, etc.

[0024] Further, the filler is one or a mixture of mica powder, bentonite, calcium carbonate, etc.

[0025] Further, the binder is one or a mixture of pregelatinized starch, potassium silicate, gelatin, etc.

[0026] Further, the preservative is one or a mixture of Kathon, benzisothiazolinone, methylisothiazolinone, etc.

[0027] Beneficial effects:

[0028] The high-strength expandable sealing tape of the present invention has good sealing effects and anti-tearing ability in different pipes, has good expansion performance, is easier to wind and fit the threads, is simple to use, and the unused part can be used again after being soaked in water without affecting the sealing effect of the product. Specific embodiments

[0029] The present invention will be described below in conjunction with specific implementation examples. It should be noted that the following examples are examples of the present invention, only for illustrating the present invention, and not for limiting the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the gist or scope of the present invention.

[0030] In the following preparation examples, examples and comparative examples, attapulgite was purchased from Hebei Hezhen Industry Co., Ltd.; pregelatinized starch was purchased from Ningjin Jiahe Energy Saving Materials Co., Ltd.; potassium silicate (potassium water glass) was purchased from Shandong Baite New Materials Co., Ltd., potassium type silica sol, mica powder, calcium carbonate were 1000 mesh; bentonite was sodium-based bentonite, purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd., 1250 mesh, whiteness 90%, water content 1.2%; Kathon was purchased from Qingdao Xiangze Chemical Co., Ltd.; polytetrafluoroethylene was purchased from Shandong Dongyue Polymer Materials Co., Ltd.

[0031] Note: The following preparations are based on 1 g as 1 part by weight;

[0032] Preparation of modified sodium polyacrylate resin:

[0033] S1: Add 10 g of attapulgite to 500 mL of 2 mol / L hydrochloric acid solution, stir at 60 °C for 2 hours, then wash with deionized water until the pH value is 7, and disperse in 500 mL of deionized water to obtain an attapulgite dispersion. Dilute 10 g of acrylic acid with a sodium hydroxide solution with a volume concentration of 20% to an acrylic acid solution with a mass concentration of 60%;

[0034] S2: Add 20 g of hydroxyethyl acrylate and 0.2 g of potassium persulfate to the attapulgite dispersion in step S1, introduce nitrogen, start stirring, heat up to 75 °C, after reacting for 3 hours, cool and pour into anhydrous ethanol for precipitation and filtration to obtain a hydroxyethyl acrylate-attapulgite product;

[0035] S3: Pour the hydroxyethyl acrylate-attapulgite product prepared in step S2 into the acrylic acid solution prepared in step S1, add 0.05 g of N,N'-methylenebisacrylamide and 0.1 g of ammonium bicarbonate, introduce nitrogen, start stirring, heat up to 75 °C, after reacting for 2 hours, lower the temperature of the reaction system to 45 °C, slowly dropwise add 10 g of ethylene glycol diglycidyl ether, after the addition is complete, continue stirring and reacting for 3 hours. After the reaction is completed, cool the reaction product to room temperature, pour it into anhydrous ethanol for precipitation, filtration and drying to obtain the modified sodium polyacrylate resin.

[0036] Preparation of coating layer A:

[0037] Step 1: Add 5 g of pregelatinized starch and 6.5 g of potassium silicate to 30 g of water, stir and dissolve, then add 1 g of benzotriazole, 8 g of glycerol, 0.05 g of Kathon, and stir evenly to obtain a mixed auxiliary material;

[0038] Step 2: Slowly add 20 g of mica powder, 20 g of bentonite, and 3.6 g of calcium carbonate to the mixed auxiliary materials prepared in Step 1, and mix them at a stirring speed of 350 revolutions per minute at 100 °C for 10 minutes to obtain a mixture.

[0039] Step 3: Finally, add 5 g of modified sodium polyacrylate resin to the mixture prepared in Step 2, and mix it at a stirring speed of 350 revolutions per minute at 100 °C for 2 minutes to obtain Coating A.

[0040] Preparation of Coating B:

[0041] Step 1: Add 7 g of pregelatinized starch and 5 g of potassium silicate to 40 g of water, stir and dissolve, then add 0.8 g of benzotriazole, 5 g of glycerol, 5 g of sorbitol, 0.03 g of Kathon, and 0.05 g of benzisothiazolinone, and stir evenly to obtain mixed auxiliary materials.

[0042] Step 2: Slowly add 20 g of mica powder, 20 g of bentonite, and 3.6 g of calcium carbonate to the mixed auxiliary materials prepared in Step 1, and mix them at a stirring speed of 350 revolutions per minute at 100 °C for 10 minutes to obtain a mixture.

[0043] Step 3: Finally, add 5 g of modified sodium polyacrylate resin to the mixture prepared in Step 2, and mix it at a stirring speed of 350 revolutions per minute at 100 °C for 2 minutes to obtain Coating B.

[0044] Preparation of Coating C:

[0045] Step 1: Add 5 g of pregelatinized starch and 6.5 g of potassium silicate to 30 g of water, stir and dissolve, then add 1 g of benzotriazole, 8 g of glycerol, and 0.05 g of Kathon, and stir evenly to obtain mixed auxiliary materials.

[0046] Step 2: Slowly add 20 g of mica powder, 20 g of bentonite, and 3.6 g of calcium carbonate to the mixed auxiliary materials prepared in Step 1, and mix them at a stirring speed of 350 revolutions per minute at 100 °C for 10 minutes to obtain a mixture.

[0047] Step 3: Finally, add 10 g of modified sodium polyacrylate resin to the mixture prepared in Step 2, and mix it at a stirring speed of 350 revolutions per minute at 100 °C for 2 minutes to obtain Coating C.

[0048] Example 1

[0049] Preparation of high-strength intumescent sealing tape:

[0050] Step 1: Dilute 5 kg of Coating A with 5 kg of water, and evenly coat the coating on a base paper with a grammage of 80 g / m 2On the surface of the non-woven fabric, the coating layer thickness is 0.5 mm and the coating amount is 200 g / m 2 ;

[0051] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60°C until the moisture content is 3%, and then cut it into a width of 10 mm and 10 m per roll to obtain a high-strength expandable sealing tape.

[0052] Example 2

[0053] Preparation of high-strength expandable sealing tape:

[0054] Step 1: Dilute 5 kg of Coating Layer A with 7.5 kg of water, and evenly coat the coating layer on the surface of the non-woven fabric with a gram weight of 150 g / m 2 On the surface of the non-woven fabric, the coating layer thickness is 2 mm and the coating amount is 500 g / m 2 ;

[0055] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60°C until the moisture content is 5%, and then cut it into a width of 10 mm and 10 m per roll to obtain a high-strength expandable sealing tape.

[0056] Example 3

[0057] Preparation of high-strength expandable sealing tape:

[0058] Step 1: Dilute 5 kg of Coating Layer B with kg of water, and evenly coat the coating layer on the surface of the non-woven fabric with a gram weight of 100 g / m 2 On the surface of the non-woven fabric, the coating layer thickness is 1 mm and the coating amount is 400 g / m 2 ;

[0059] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60°C until the moisture content is 3%, and then cut it into a width of 10 mm and 10 m per roll to obtain a high-strength expandable sealing tape.

[0060] Example 4

[0061] Preparation of high-strength expandable sealing tape:

[0062] Step 1: Dilute 5 kg of Coating Layer C with 5 kg of water, and evenly coat the coating layer on the surface of the non-woven fabric with a gram weight of 100 g / m 2 On the surface of the non-woven fabric, the coating layer thickness is 1 mm and the coating amount is 400 g / m 2 ;

[0063] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60°C until the moisture content is 3%, and then cut it into a width of 10 mm and 10 m per roll to obtain a high-strength expandable sealing tape.

[0064] Example 5

[0065] Preparation of high-strength expandable sealing tape:

[0066] Step 1: Dilute 5 kg of coating layer A with 5 kg of water, and evenly coat the coating layer on the surface of non-woven fabric with a grammage of 80 g / m 2 , with a coating layer thickness of 0.5 mm and a coating amount of 150 g / m 2 ;

[0067] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60 °C until the moisture content is 3%, and then cut it into a width of 10 mm, 10 m per roll, to obtain the high-strength expandable sealing tape.

[0068] Comparative Example 1

[0069] Preparation of high-strength expandable sealing tape:

[0070] Step 1: Weigh 5 kg of polytetrafluoroethylene as the coating layer, and evenly coat the coating layer on the surface of non-woven fabric with a grammage of 80 g / m 2 , with a coating layer thickness of 0.5 mm and a coating amount of 200 g / m 2 ;

[0071] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60 °C until the moisture content is 3%, and then cut it into a width of 10 mm, 10 m per roll, to obtain the high-strength expandable sealing tape.

[0072] Comparative Example 2

[0073] Step 1: Weigh 5 kg of modified sodium polyacrylate resin as the coating layer, and evenly coat the coating layer on the surface of non-woven fabric with a grammage of 80 g / m 2 , with a coating layer thickness of 0.5 mm and a coating amount of 200 g / m 2 ;

[0074] Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60 °C until the moisture content is 3%, and then cut it into a width of 10 mm, 10 m per roll, to obtain the high-strength expandable sealing tape.

[0075] Performance test:

[0076] 1. Sealing performance test: Test according to the standard of GB / T 20801.5-2006 "Code for Pressure Piping - Industrial Piping", water tightness cyclic test, wind the sealing tape around the standard threaded joint (DN50 pipe), cycle 100 times under dynamic pressure (0.5 - 2.5 MPa), and then conduct high and low temperature cycle (10 times) in the range of -40 °C to 120 °C to test the leakage amount.

[0077] 2. Tensile strength: Tested according to GB / T 1040.3 "Test Method for Tensile Properties of Plastics". Use a universal material testing machine, cut samples according to standard dimensions (25 mm × 150 mm), with a tensile rate of 500 mm / min, and record the elongation at break.

[0078] 3. Swelling test: Tested according to ASTM D570 "Standard Test Method for Water Absorption of Plastics". Immerse the sealing tape in water at 25 °C, weigh and measure the dimensions after 10 minutes, and calculate the volume swelling rate.

[0079] 4. Reusability verification: Immerse and dry the sealing tape repeatedly in water for activation 3 times, test the swelling rate, calculate the swelling rate, and a swelling rate decay ≤ 5% is considered qualified.

[0080] Test the high-strength swelling sealing tapes prepared in each example and comparative example according to the above test methods, and the test results are shown in Table 2.

[0081] Table 2

[0082]

[0083] It can be seen from Table 1 that the high-strength swelling sealing tapes prepared in Examples 1-3 have excellent sealing effects and anti-tearing abilities. At the same time, they have good swelling properties. The unused sealing tapes can be used again after being immersed in water, without affecting the product's sealing effect. From the comparison between Example 4 and the examples, it can be known that when preparing the coating layer, adding too much modified sodium polyacrylate resin will cause the sealing performance, anti-tearing ability, and swelling performance of the prepared high-strength swelling sealing tape to decline, and the reusability becomes low, failing to achieve the expected effect. From the comparison between Example 5 and Example 1, it can be known that when preparing the high-strength swelling sealing tape, reducing the coating layer amount will cause the sealing performance, anti-tearing ability, and swelling performance of the prepared high-strength swelling sealing tape to decline, and the reusability becomes low, failing to achieve the expected effect. From the comparison between Comparative Example 1 and Example 1, it can be known that replacing the modified sodium polyacrylate resin with polytetrafluoroethylene will cause the sealing performance, anti-tearing ability, and swelling performance of the prepared high-strength swelling sealing tape to decline, and the reusability becomes low, failing to achieve the expected effect. From the comparison between Comparative Example 2 and Example 1, it can be known that replacing the coating layer with modified sodium polyacrylate resin will cause the sealing performance and anti-tearing ability of the prepared high-strength swelling sealing tape to decline. Although sodium polyacrylate resin itself has high water absorption, the lack of a humectant may affect its water absorption rate and water retention ability, resulting in unstable swelling rate and low reusability, failing to achieve the expected effect.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength expandable sealing strip, characterized in that, It includes a material to be coated and a coating layer coated on its surface; the material to be coated is non-woven fabric; the components of the coating layer by weight include: 2-5 parts of modified sodium polyacrylate resin, 0.8-1.5 parts of benzotriazole, 5-15 parts of humectant, 30-50 parts of filler, 10-15 parts of binder, 0.02-0.1 part of preservative, and 20-40 parts of water.

2. The high-strength expandable sealing tape according to claim 1, characterized in that, The non-woven fabric is a polyester fiber non-woven fabric or a glass fiber non-woven fabric, with a gram weight of 80-150 g / m 2 .

3. The high-strength expandable sealing tape according to claim 1, characterized in that, The thickness of the coating layer is 0.5 - 2 mm, and the coating amount is 200 - 500 g / m 2 .

4. The high-strength expandable sealing strip according to claim 1, characterized in that The preparation of the coating layer includes the following steps: Step 1: Add the binder to water, stir and dissolve it, then add benzotriazole, humectant, and preservative, and stir evenly to obtain a mixed auxiliary material. Step 2: Slowly add the filler to the mixed auxiliary material prepared in Step 1, and knead at a stirring speed of 300-450 revolutions per minute at 100-120 °C for 10-15 minutes to obtain a mixture. Step 3: Finally, add the modified sodium polyacrylate resin to the mixture prepared in Step 2, and knead at a stirring speed of 300-450 revolutions per minute at 100-120 °C for 2-5 minutes to obtain the coating layer.

5. A high-strength expandable sealing tape according to claim 4, characterized in that, The modified sodium polyacrylate resin is prepared by reacting hydroxyethyl acrylate, attapulgite, acrylic acid, ammonium bicarbonate, and ethylene glycol diglycidyl ether.

6. The preparation method of a high-strength expandable sealing tape according to any one of claims 1-5, characterized in that, It includes the following steps: Step 1: Dilute the coating layer with water, evenly coat the coating layer on the surface of the non-woven fabric, and control the coating thickness. Step 2: After the coating in Step 1 is completed, dry the coated non-woven fabric at 60-80 °C, and then cut it into a width of 10-50 mm and a length of 5-20 m per roll to obtain a high-strength expandable sealing tape.

7. The preparation method of a high-strength expandable sealing tape according to claim 6, characterized in that, In Step 1, the mass ratio of water to the coating layer is 1-1.5:1; the moisture content of the coated non-woven fabric after drying in Step 2 is 1-5%.

8. Use of a high-strength expandable sealing tape according to any one of claims 1-5, characterized in that The high-strength expandable sealing tape is applied to the sealing of pipe threaded connections.

9. The application of a high-strength expandable sealing tape according to claim 8, characterized in that The usage method of the high-strength expandable sealing tape includes the following steps: Immerse the high-strength expandable sealing tape in water to activate it, and then wind it around the pipe threaded part for 2-4 layers.

10. The application of a high-strength expandable sealing strip according to claim 9, characterized in that, A pre-tightening force of 5-15 N is applied when winding the high-strength expandable sealing tape.

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