High-strength flame-retardant CPVC (Chlorinated Polyvinyl Chloride) solvent type adhesive and preparation method thereof

Abstract

The invention discloses a high-strength flame-retardant CPVC (chlorinated polyvinyl chloride) solvent type adhesive which is prepared from the following raw materials in parts by weight: 15-25 parts of CPVC resin, 5-10 parts of chlorinated rubber, 0.5-1.0 part of vinyltriethoxysilane, 51-70 parts of a mixed solvent, 3-8 parts of a flame retardant, 1-3 parts of a stabilizer, 0-2 parts of a tackifier and 1-2 parts of a plasticizer. A preparation method of the high-strength flame-retardant CPVC solvent type adhesive comprises the following steps: adding the mixed solvent into a stirrer, adding the CPVC resin, the chlorinated rubber and the vinyltriethoxysilane, dissolving and stirring for 3 hours, then adding the stabilizer and the flame retardant, continuously stirring for 30 minutes, then adding the plasticizer and the tackifier, uniformly stirring, and filtering to obtain the product. The high-strength flame-retardant CPVC solvent type adhesive disclosed by the invention is relatively good in bonding strength, water pressure bursting strength and oxygen index, and wide in application.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a high-strength flame-retardant CPVC solvent-based adhesive and its preparation method. Background Technology

[0002] CPVC (chlorinated polyvinyl chloride) is a high-performance engineering plastic with excellent heat resistance, chemical corrosion resistance, and mechanical properties, making it widely used in construction, chemical, and electrical industries. Due to its superior high-temperature resistance and flame-retardant properties, along with high mechanical strength and resistance to chemical corrosion, CPVC piping systems have gradually replaced metal pipes as the mainstream choice for fire protection and water distribution systems. Pipe connections are generally made using solvent-based adhesives. The adhesive softens and corrodes the bonding surfaces of the pipe fittings; as the solvent evaporates, intermolecular forces bind the two surfaces together, and the bond solidifies, generating strength.

[0003] Traditional CPVC solvent-based adhesives have limited strength, making them unsuitable for applications requiring high connection strength. For example, in building water supply and drainage systems, pipe connections need to withstand pressure and external forces. Insufficient adhesive strength can lead to leaks at pipe joints, affecting system operation. Furthermore, most existing adhesives have poor flame retardant properties. In areas with high fire safety requirements, such as electrical equipment housings and decorative materials in public places, adhesives can easily ignite and spread fire in the event of a fire, posing serious safety hazards. In addition, some adhesives exhibit poor stability during storage, prone to stratification and sedimentation, leading to performance degradation and affecting usability. Moreover, some adhesives use highly toxic solvent systems, posing risks to the environment and the health of operators, failing to meet modern environmental protection standards.

[0004] CN106318279B discloses a high-strength CPVC solvent-based adhesive and its preparation method, belonging to the field of adhesive technology. It consists of the following components by weight: 10-15 parts CPVC resin, 55-73 parts CPVC solvent, 1-5 parts reinforcing agent, 10-30 parts reinforcing agent solvent, and 0-2 parts filler. The reinforcing agent is cellulose acetate, with a degree of esterification of 200-300 and an acetyl content of 32-42%. The high-strength CPVC solvent-based adhesive of this invention exhibits excellent heat resistance and bonding properties, and is mainly used in CPVC piping systems, especially suitable for CPVC piping systems containing hot fluids. However, it still does not solve the problems of the prior art.

[0005] With the continuous development of technology and the expansion of application fields, higher requirements are being placed on the performance of CPVC solvent-based adhesives. Developing a CPVC solvent-based adhesive that combines high-strength bonding performance with excellent flame-retardant properties is of significant practical importance. Summary of the Invention

[0006] The high-strength, flame-retardant CPVC solvent-based adhesive provided by this invention is composed of the following raw materials in parts by weight: 15-25 parts CPVC resin, 5-10 parts chlorinated rubber, 0.5-1.0 parts vinyltriethoxysilane, 51-70 parts mixed solvent, 3-8 parts flame retardant, 1-3 parts stabilizer, 0-2 parts tackifier, and 1-2 parts plasticizer. CPVC resin and chlorinated rubber, as the main film-forming substances, work together to impart excellent mechanical properties to the adhesive. The use of vinyltriethoxysilane coupling agent further enhances the bonding force between the adhesive and the bonded materials, improving the adhesive strength and meeting the requirements of various applications with high connection strength.

[0007] Furthermore, the CPVC resin has a K-value ranging from 57 to 67 and a chlorine content of 66% to 69%. The K-value limits the degree of polymerization of the resin, ensuring that the resin has good solubility and mechanical properties. The chlorine content endows the CPVC resin with certain flame-retardant properties, while also enhancing its chemical corrosion resistance.

[0008] Furthermore, the chlorinated rubber has a chlorine content of 62–68 wt% and an initial thermal decomposition temperature of not less than 160°C. Chlorinated rubber can improve the flexibility, water resistance, and weather resistance of adhesives, while also exhibiting good compatibility with CPVC resin, thus synergistically enhancing the overall performance of the adhesive.

[0009] Further, the mixed solvent is a mixture of methyltetrahydrofuran, acetone, and methyl acetate, or a mixture of choline chloride, urea, and γ-valerolactone, wherein the mass ratio of methyltetrahydrofuran, acetone, and methyl acetate is 1:1:1, and the mass ratio of choline chloride, urea, and γ-valerolactone is 1:1:0.5. The mixture of choline chloride, urea, and γ-valerolactone forms a eutectic solvent, where hydrogen bonding enhances the solubility of CPVC. γ-valerolactone is a bio-based solvent, resulting in a combination with good solubility and low VOC emissions.

[0010] Furthermore, the flame retardant is a POSS nano flame retardant, which is prepared as follows: 2.5 kg of octachloropropyl cage-type silsesquioxane is dissolved in 150 L of acetonitrile, then 1.67 kg of tetramethylethylenediamine and 0.18 kg of sodium iodide are added. After stirring and reacting at 60 °C for 2 hours, the filter cake is filtered and dried to obtain 3 kg of product POSS-[TMEDA]Cl2. POSS-[TMEDA]Cl2 is dissolved in 18 L of deionized water, and then 2.7 kg of potassium hexafluorophosphate is added. The reaction is carried out at 20-30 °C for 24 hours. After the reaction is completed, the reactants are poured into 60 L of acetonitrile to precipitate the product. The resulting mixture is filtered, and the filter cake is vacuum dried to obtain 3.3 kg of POSS nano flame retardant. POSS nano flame retardant is a temperature-sensitive flame retardant modified with ionic liquid. When the temperature rises, it triggers the release of free radicals, which combine with Cl· generated from the dehydrochlorination of CPVC, terminating the chain reaction. At the same time, during combustion, it decomposes to generate PO· free radicals, which work together with POSS to form a cross-linked network structure of Si-OC, thereby improving the flame retardant performance of the adhesive.

[0011] Furthermore, the flame retardant is nano-magnesium hydroxide with carbon nanotubes coated on its surface. The nano-magnesium hydroxide forms a three-dimensional thermally conductive network through the surface coating of carbon nanotubes. During combustion, it decomposes and absorbs heat, while the carbon nanotubes promote the densification of the char layer and increase the oxygen index.

[0012] Furthermore, the plasticizer is epoxy methyl ricinoleate, which, as a bio-based plasticizer, replaces traditional petroleum-based plasticizers. The intermolecular forces between the epoxy groups of epoxy methyl ricinoleate and the Cl atoms of CPVC resin weaken the intermolecular forces of CPVC molecules and improve processing fluidity. At the same time, its long-chain fatty acid structure interweaves with the cage structure of POSS flame retardant, enhancing the dispersibility of the flame retardant and increasing the oxygen index by more than 2%.

[0013] Furthermore, the stabilizer is a thiol methyltin and epoxidized vegetable oil complex, wherein the epoxidized vegetable oil includes epoxidized soybean oil and epoxidized linseed oil, and the epoxy value is 0.48-0.55 mol / 100g.

[0014] Furthermore, the tackifier is nano-silica and hydrogenated terpene resin, wherein the specific surface area of ​​nano-silica is 180-220 m² / g, the softening point of hydrogenated terpene resin is between 90-120℃, and the mass ratio of nano-silica to hydrogenated terpene resin is between 1:(2~5). Due to its unique three-dimensional network structure and numerous silanol groups on its surface, the tackifier silica penetrates the hydrogenated terpene resin, cooperating with the coupling agent at the bond sites, thus increasing tack while preventing sedimentation, further improving the long-term storage stability of the adhesive.

[0015] This invention provides a method for preparing the high-strength flame-retardant CPVC solvent-based adhesive described above: A mixed solvent is added to a nitrogen-sealed star-shaped stirrer with a jacket or coil, and the temperature is controlled at 60-70°C using a water bath. CPVC resin, chlorinated rubber, and vinyltriethoxysilane are added and stirred for 3 hours to dissolve. Then, a stabilizer and flame retardant are added, and stirring continues for 30 minutes. Finally, a plasticizer and a tackifier are added, and the mixture is stirred until homogeneous before filtration to obtain the high-strength flame-retardant CPVC solvent-based adhesive.

[0016] The present invention has the following advantages: (1) The formulation of this invention is reasonably designed, and the fully enclosed production process is environmentally friendly. The solubility parameters of the mixed solvent are close to those of POSS nano flame retardant, which better solves the problem of nanoparticle dispersion compatibility.

[0017] (2) The use of a dual-composite system of stabilizers captures free radicals and forms ionic coordination with POSS nano flame retardants to achieve high thermal stability. The tackifier uses fumed nano-sized silica combined with hydrogenated terpene resin, which improves thixotropy, stability and interfacial strength. Unlike traditional tackifiers, it is more suitable for fire-fighting pipeline systems under high pressure.

[0018] (3) This invention solves the shortcomings of traditional adhesives such as low flame retardancy and poor high temperature durability. It has a wider range of applications, is economical and environmentally friendly, and meets the emission requirements of VOC organic matter. In addition to being applicable to ordinary CPVC hot and cold water systems, it can also be applied to other CPVC pipe systems, including industrial chemical pipe systems and high-pressure fire protection CPVC pipe systems. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 A high-strength flame-retardant CPVC solvent-based adhesive is composed of the following raw materials: 20 kg of CPVC resin, 5 kg of chlorinated rubber, 0.5 kg of vinyltriethoxysilane, 18 kg of methyltetrahydrofuran, 18 kg of acetone, 18 kg of methyl acetate, 3 kg of POSS nano flame retardant, 1 kg of stabilizer, 1 kg of tackifier, and 1 kg of epoxy methyl ricinoleate.

[0021] The CPVC resin has a K value of 62-65 and a chlorine content of 68%.

[0022] The chlorinated rubber has a chlorine content of 64 wt% and an initial thermal decomposition temperature of 162°C.

[0023] The stabilizer is a complex of 0.5 kg methyltin mercaptan and 0.5 kg epoxidized vegetable oil, including epoxidized soybean oil and epoxidized linseed oil, with an epoxy value of 0.50 mol / 100g.

[0024] The tackifier is nano-silica and hydrogenated terpene resin, wherein the specific surface area of ​​nano-silica is 210 m² / g, the softening point of hydrogenated terpene resin is 110℃, and the mass ratio of nano-silica to hydrogenated terpene resin is 1:3.

[0025] The preparation method of the POSS nano flame retardant is as follows: 2.5 kg of octachloropropyl cage-type silsesquioxane is dissolved in 150 L of acetonitrile, then 1.67 kg of tetramethylethylenediamine and 0.18 kg of sodium iodide are added. After stirring and reacting at 60 °C for 2 hours, the filter cake is filtered and dried to obtain 3 kg of product POSS-[TMEDA]Cl2. POSS-[TMEDA]Cl2 is dissolved in 18 L of deionized water, and then 2.7 kg of potassium hexafluorophosphate is added. The reaction is carried out at 20-30 °C for 24 hours. After the reaction is completed, the reactants are poured into 60 L of acetonitrile to precipitate the product. The resulting mixture is filtered, and the filter cake is vacuum dried to obtain 3.3 kg of POSS nano flame retardant.

[0026] The preparation method of the above-mentioned high-strength flame-retardant CPVC solvent-based adhesive is characterized in that a mixed solvent is added to a nitrogen-sealed star-shaped stirrer with a jacket or coil, the temperature is controlled at 60-70°C by a water bath, CPVC resin, chlorinated rubber and vinyltriethoxysilane are added and stirred for 3 hours, then a stabilizer and flame retardant are added, and stirring is continued for 30 minutes, then a plasticizer and a tackifier are added, and after stirring evenly, the mixture is filtered to obtain the high-strength flame-retardant CPVC solvent-based adhesive.

[0027] Example 2 A high-strength flame-retardant CPVC solvent-based adhesive is composed of the following raw materials: 22 kg of CPVC resin, 8 kg of chlorinated rubber, 0.8 kg of vinyltriethoxysilane, 18 kg of methyltetrahydrofuran, 18 kg of acetone, 18 kg of methyl acetate, 3.3 kg of POSS nano flame retardant, 2 kg of stabilizer, 2 kg of tackifier, and 1 kg of epoxy methyl ricinoleate.

[0028] The CPVC resin has a K value of 62-65 and a chlorine content of 68%.

[0029] The chlorinated rubber has a chlorine content of 64 wt% and an initial thermal decomposition temperature of 162°C.

[0030] The stabilizer is a complex of 1 kg thiol methyltin and 1 kg epoxidized vegetable oil, wherein the epoxidized vegetable oil includes epoxidized soybean oil and epoxidized linseed oil, and the epoxy value is 0.50 mol / 100g.

[0031] The tackifier is nano-silica and hydrogenated terpene resin, wherein the specific surface area of ​​nano-silica is 210 m² / g, the softening point of hydrogenated terpene resin is 110℃, and the mass ratio of nano-silica to hydrogenated terpene resin is 1:3.

[0032] The preparation method of the POSS nano flame retardant is as follows: 2.5 kg of octachloropropyl cage-type silsesquioxane is dissolved in 150 L of acetonitrile, then 1.67 kg of tetramethylethylenediamine and 0.18 kg of sodium iodide are added. After stirring and reacting at 60 °C for 2 hours, the filter cake is filtered and dried to obtain 3 kg of product POSS-[TMEDA]Cl2. POSS-[TMEDA]Cl2 is dissolved in 18 L of deionized water, and then 2.7 kg of potassium hexafluorophosphate is added. The reaction is carried out at 20-30 °C for 24 hours. After the reaction is completed, the reactants are poured into 60 L of acetonitrile to precipitate the product. The resulting mixture is filtered, and the filter cake is vacuum dried to obtain 3.3 kg of POSS nano flame retardant.

[0033] The preparation method of the above-mentioned high-strength flame-retardant CPVC solvent-based adhesive is characterized in that a mixed solvent is added to a nitrogen-sealed star-shaped stirrer with a jacket or coil, the temperature is controlled at 60-70°C by a water bath, CPVC resin, chlorinated rubber and vinyltriethoxysilane are added and stirred for 3 hours, then a stabilizer and flame retardant are added, and stirring is continued for 30 minutes, then a plasticizer and a tackifier are added, and after stirring evenly, the mixture is filtered to obtain the high-strength flame-retardant CPVC solvent-based adhesive.

[0034] Example 3 A high-strength flame-retardant CPVC solvent-based adhesive is composed of the following raw materials: 20 kg of CPVC resin, 5 kg of chlorinated rubber, 0.5 kg of vinyltriethoxysilane, 18 kg of methyltetrahydrofuran, 18 kg of acetone, 18 kg of methyl acetate, 3 kg of nano-magnesium hydroxide coated with carbon nanotubes, 1 kg of stabilizer, 1 kg of tackifier, and 1 kg of epoxy methyl ricinoleate.

[0035] The CPVC resin has a K value of 62-65 and a chlorine content of 68%.

[0036] The chlorinated rubber has a chlorine content of 64 wt% and an initial thermal decomposition temperature of 162°C.

[0037] The stabilizer is a complex of 0.5 kg thiol methyltin and 0.5 kg epoxidized vegetable oil, including epoxidized soybean oil and epoxidized linseed oil, with an epoxy value of 0.50 mol / 100 g.

[0038] The tackifier is nano-silica and hydrogenated terpene resin, wherein the specific surface area of ​​nano-silica is 210 m² / g, the softening point of hydrogenated terpene resin is 110℃, and the mass ratio of nano-silica to hydrogenated terpene resin is 1:3.

[0039] The preparation method of the above-mentioned high-strength flame-retardant CPVC solvent-based adhesive is characterized in that a mixed solvent is added to a nitrogen-sealed star-shaped stirrer with a jacket or coil, the temperature is controlled at 60-70°C by a water bath, CPVC resin, chlorinated rubber and vinyltriethoxysilane are added and stirred for 3 hours, then a stabilizer and flame retardant are added, and stirring is continued for 30 minutes, then a plasticizer and a tackifier are added, and after stirring evenly, the mixture is filtered to obtain the high-strength flame-retardant CPVC solvent-based adhesive.

[0040] Example 4 A high-strength flame-retardant CPVC solvent-based adhesive is composed of the following raw materials: 20 kg of CPVC resin, 5 kg of chlorinated rubber, 0.5 kg of vinyltriethoxysilane, 60 kg of mixed solvent, 3 kg of POSS nano flame retardant, 1 kg of stabilizer, 1 kg of tackifier, and 1 kg of epoxy methyl ricinoleate.

[0041] The CPVC resin has a K value of 62-65 and a chlorine content of 68%.

[0042] The chlorinated rubber has a chlorine content of 64 wt% and an initial thermal decomposition temperature of 162°C.

[0043] The stabilizer is a complex of 0.5 kg thiol methyltin and 0.5 kg epoxidized vegetable oil, including epoxidized soybean oil and epoxidized linseed oil, with an epoxy value of 0.50 mol / 100 g.

[0044] The tackifier is nano-silica and hydrogenated terpene resin, wherein the specific surface area of ​​nano-silica is 210 m² / g, the softening point of hydrogenated terpene resin is 110℃, and the mass ratio of nano-silica to hydrogenated terpene resin is 1:3.

[0045] The preparation method of the POSS nano flame retardant is as follows: 2.5 kg of octachloropropyl cage-type silsesquioxane is dissolved in 150 L of acetonitrile, then 1.67 kg of tetramethylethylenediamine and 0.18 kg of sodium iodide are added. After stirring and reacting at 60 °C for 2 hours, the filter cake is filtered and dried to obtain 3 kg of product POSS-[TMEDA]Cl2. POSS-[TMEDA]Cl2 is dissolved in 18 L of deionized water, and then 2.7 kg of potassium hexafluorophosphate is added. The reaction is carried out at 20-30 °C for 24 hours. After the reaction is completed, the reactants are poured into 60 L of acetonitrile to precipitate the product. The resulting mixture is filtered, and the filter cake is vacuum dried to obtain 3.3 kg of POSS nano flame retardant.

[0046] The mixed solvent is a mixture of 24 kg of choline chloride, 24 kg of urea, and 12 kg of γ-valerol.

[0047] The preparation method of the above-mentioned high-strength flame-retardant CPVC solvent-based adhesive is characterized in that choline chloride, urea, and γ-valerol are sequentially added to a nitrogen-sealed star-shaped stirrer with a jacket or coil, the temperature is controlled at 60-70°C by water bath, and the mixture is stirred and dissolved. Then, CPVC resin, chlorinated rubber, and vinyltriethoxysilane are added and stirred for 3 hours. After that, stabilizer and flame retardant are added, and stirring is continued for 30 minutes. Then, plasticizer and tackifier are added, and the mixture is stirred evenly and then filtered to obtain the high-strength flame-retardant CPVC solvent-based adhesive.

[0048] Comparative Example 1 The epoxy methyl ricinoleate in Example 1 is removed, and the rest is the same as in Example 1, so it will not be repeated here.

[0049] The properties of the high-strength flame-retardant CPVC solvent-based adhesives prepared in the examples and comparative examples were tested according to QB / T2568-2002 and GB33372-2020, and the oxygen index was tested according to GB / T2406.2-2009 Method B. The test results are shown in Table 1.

[0050] The oxygen index test method is as follows: For sample preparation, a mold cavity with a length of 200 mm, a width of 20 mm, and a thickness of 0.2 mm was made using a stainless steel sample block. Polytetrafluoroethylene (PTFE) spray was applied into the cavity. After pouring the adhesive into the mold, it was scraped in one direction at a constant rate using a scraper. The mold cavity was placed in a vacuum drying oven at 120℃ and a vacuum of 2 kPa for 40 minutes. After drying, it was removed, cooled to room temperature, and demolded to obtain the adhesive sample. The above sample was tested for oxygen index according to Method B of GB / T2406.2-2009. The test results are shown in Table 1.

[0051] Table 1 The test data from Examples 1-4 show that the high-strength flame-retardant CPVC solvent-based adhesive prepared by this invention exhibits good bonding strength, hydrostatic burst strength, and oxygen index. Data from Example 4 indicates that using a eutectic solvent yields the best results. Data from Comparative Example 1 shows that epoxy methyl ricinoleate can improve product performance, particularly by increasing the oxygen index.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-strength flame-retardant CPVC solvent-based adhesive, characterized in that, It is composed of the following raw materials in parts by weight: 15-25 parts CPVC resin, 5-10 parts chlorinated rubber, 0.5-1.0 parts vinyltriethoxysilane, 51-70 parts mixed solvent, 3-8 parts flame retardant, 1-3 parts stabilizer, 0-2 parts tackifier, and 1-2 parts plasticizer.

2. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The CPVC resin has a K value range of 57-67 and a chlorine content of 66-69%.

3. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The chlorinated rubber has a chlorine content of 62–68 wt% and an initial thermal decomposition temperature of not less than 160°C.

4. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The mixed solvent is a mixture of methyltetrahydrofuran, acetone and methyl acetate, or a mixture of choline chloride, urea and γ-valerolactone, wherein the mass ratio of methyltetrahydrofuran, acetone and methyl acetate is 1:1:1, and the mass ratio of choline chloride, urea and γ-valerolactone is 1:1:0.

5.

5. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The flame retardant is a POSS nano flame retardant, which is prepared as follows: octachloropropyl cage-type silsesquioxane is dissolved in acetonitrile, then tetramethylethylenediamine and sodium iodide are added. After stirring and reacting at 60°C for 2 hours, the filter cake is filtered and dried to obtain the product POSS-[TMEDA]Cl2. POSS-[TMEDA]Cl2 is dissolved in deionized water, and then potassium hexafluorophosphate is added. The mixture is reacted at 20-30°C for 24 hours. After the reaction is completed, the reactants are poured into acetonitrile to precipitate the product. The resulting mixture is filtered, and the filter cake is vacuum dried to obtain the POSS nano flame retardant.

6. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The flame retardant is nano-magnesium hydroxide with carbon nanotubes coated on its surface.

7. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The plasticizer is epoxy methyl ricinoleate.

8. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The stabilizer is a complex of thiol methyltin and epoxidized vegetable oil, including epoxidized soybean oil and epoxidized linseed oil, with an epoxy value of 0.48-0.55 mol / 100g.

9. The high-strength flame-retardant CPVC solvent-based adhesive according to claim 1, characterized in that, The tackifier is nano-silica and hydrogenated terpene resin, wherein the specific surface area of ​​nano-silica is 180-220 m² / g, the softening point of hydrogenated terpene resin is between 90-120℃, and the mass ratio of nano-silica to hydrogenated terpene resin is between 1:(2~5).

10. A method for preparing a high-strength flame-retardant CPVC solvent-based adhesive according to any one of claims 1-8, characterized in that, The mixed solvent is added to a nitrogen-sealed star-shaped stirrer with a jacket or coil. The temperature is controlled at 60-70℃ by water bath. CPVC resin, chlorinated rubber and vinyltriethoxysilane are added and stirred for 3 hours to dissolve. Then, stabilizer and flame retardant are added and stirring is continued for 30 minutes. Plasticizer and tackifier are then added and stirred evenly. The mixture is then filtered to obtain a high-strength flame-retardant CPVC solvent-based adhesive.

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