Corrosion-resistant PVC adhesive strip for pouring acrylic plate and preparation method thereof

Abstract

The application discloses a kind of corrosion-resistant PVC adhesive strips for pouring acrylic plate and preparation method thereof, comprising: 100 parts of PVC resin with polymerization degree of 2500, 35-55 parts of dibutyl phthalate, 3-8 parts of epoxy soybean oil, 5-10 parts of heat stabilizer, 10-30 parts of inorganic filler, 1-5 parts of lubricant.Further add 20-40 parts of trioctyl trimellitate, 5-15 parts of butyronitrile rubber.The application combines macromolecular plasticizer with high polymerization degree PVC resin powder, and the plasticizer is closely combined with resin network, so that MMA liquid immersion does not easily precipitate and migrate, and the problem of acrylic corrosion is solved from the root.The weather resistance of PVC adhesive strip is enhanced, and after long-term use in high temperature environment, the adhesive strip can still maintain good elasticity and mechanical properties, and is not easy to deform and shrink.After testing, the PVC adhesive strip is not corroded after 30H of MMA liquid immersion, and the shrinkage rate is 3% after 2 hours of 120 degree high temperature treatment.

Description

Technical Field

[0001] This invention relates to the field of extruded PVC elastomer materials, specifically to a corrosion-resistant PVC strip for casting acrylic sheets and its preparation method. The PVC strip can meet the requirement of not corroding and cracking after prolonged contact with MMA (methyl methacrylate). Background Technology

[0002] In the production process of casting acrylic sheets, a PVC sealing strip needs to be installed between two tempered glass molds to form an injection cavity. After the acrylic prepolymer is injected into the cavity, the PVC strip and the mold undergo two processes: water bath polymerization and high-temperature polymerization. The PVC strip needs to be immersed in the acrylic prepolymer for a long time and then subjected to a high-temperature treatment of 60℃-120℃. During this period, the PVC strip needs to maintain good sealing performance, and at the same time, it must not corrode, crack, deform, or affect the polymerization rate of the acrylic prepolymer. This requires the PVC strip to have resistance to MMA corrosion, high-temperature dimensional stability, and compatibility with the polymerization process.

[0003] Currently, most PVC sealing strips on the market use DOP (dibutyl phthalate) as a plasticizer. This type of plasticizer has a small molecular weight and good compatibility with the organic solvent MMA. Therefore, during the production of acrylic sheets using DOP-plasticized PVC strips, the plasticizer inside the PVC is very easy to precipitate and migrate. At the same time, MMA, as a solvent, penetrates into the PVC molecular chains, thereby reducing the intermolecular forces between the PVC molecular chains, causing environmental stress cracking and corrosion of the material, ultimately leading to the cracking of the sealing strip and further affecting the production quality of the acrylic sheets.

[0004] Therefore, developing a PVC adhesive strip specifically designed for casting acrylic sheets, possessing excellent chemical corrosion resistance, strong bonding with acrylic materials, and good weather resistance, as well as its preparation method, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a corrosion-resistant PVC adhesive strip for casting acrylic sheets and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A corrosion-resistant PVC strip for casting acrylic sheets comprises the following components in parts by weight: 100 parts of PVC resin with a degree of polymerization of 2500, Trioctyl trimellitate (TOTM) 20-40 parts; Dibutyl phthalate (DOP) 35-55 parts; Epoxidized soybean oil (ESO) 3-8 parts; 5-10 parts heat stabilizer; 10-30 parts of inorganic filler; 1-5 parts lubricant; 5-15 parts of nitrile rubber.

[0007] In the above scheme, the combination of PVC resin with a degree of polymerization of 2500 and trioctyl trimellitate is the core component of the PVC adhesive strip of this invention. The high-polymerization-degree PVC resin has longer and more tightly intertwined molecular chains, forming a physical network that more effectively binds plasticizer molecules, slowing their migration to MMA. Simultaneously, the high-polymerization-degree resin itself has better thermal stability, which can delay molecular chain movement at high temperatures, further suppressing dimensional changes. Meanwhile, TOTM molecules are large in volume and highly polar, forming a strong interaction with the molecular chains of high-polymerization-degree PVC, further reducing plasticizer precipitation and improving corrosion resistance.

[0008] The heat stabilizer is one or a mixture of several of barium stearate, zinc stearate, and tris[2,4-di-tert-butylphenyl]phosphite.

[0009] The inorganic filler is selected from one or a mixture of several of the following: light calcium carbonate, precipitated barium sulfate, and nano-silica.

[0010] The lubricant is one or a mixture of calcium stearate, polyethylene wax, and stearic acid.

[0011] The acrylonitrile content of the nitrile rubber is 20%, 35%, or 40%.

[0012] This invention further discloses a method for preparing corrosion-resistant PVC for casting acrylic sheets, comprising the following steps: Step 1: Add 100 parts of PVC resin with a degree of polymerization of 2500, 20-40 parts of trioctyl trimellitate, 35-55 parts of dibutyl phthalate, 3-8 parts of epoxidized soybean oil, and 5-10 parts of heat stabilizer to a high-speed mixer and stir for at least 2 minutes for initial mixing at a speed of 2500 r / min and a frequency of 45 Hz. Then add 5-10 parts of heat stabilizer and mix at high speed for at least 3 minutes at a speed of 2500 r / min and a frequency of 45 Hz. Step 2: Continue to add 10-30 parts of inorganic filler, 1-5 parts of lubricant, and 5-15 parts of nitrile rubber, and then knead at high speed for 4 minutes in a high-speed mixer at a speed of 2500 r / min and a frequency of 45 Hz. Step 3: When extruding using a single-screw extruder, the temperature of the feeding zone of the single-screw extruder is 145-150℃. The screw is divided into four temperature zones from the feed to the extrusion port: Zone 1 temperature is set at 160-165℃, Zone 2 temperature is set at 170-175℃, Zone 3 temperature is set at 180-185℃, and Zone 4 temperature is set at 190-195℃. The screw speed is set at 25-35 rpm. Step 4: Cool the extruded PVC strip with cooling water, and then use a traction machine to pull and wind the PVC strip.

[0013] After adopting the above technical solutions, the beneficial effects of the present invention are as follows: This invention relates to a corrosion-resistant PVC strip for casting acrylic sheets, which is based on 100 parts of PVC resin with a degree of polymerization of 2500, 35-55 parts of dibutyl phthalate, 3-8 parts of epoxidized soybean oil, 5-10 parts of heat stabilizer, 10-30 parts of inorganic filler, and 1-5 parts of lubricant. Further added are 20-40 parts of trioctyl trimellitate and 5-15 parts of nitrile rubber.

[0014] Compared to existing technologies, this invention utilizes a combination of macromolecular plasticizers and high-polymerization-degree PVC resin powder. The plasticizer and resin network are tightly bonded, preventing easy precipitation and migration during MMA immersion, thus fundamentally solving the acrylic corrosion problem. Simultaneously, the weather resistance of the PVC strip is enhanced. Even under high-temperature environments, the strip maintains good elasticity and mechanical properties after long-term use, and is not easily deformed or shrunk. Testing showed that the PVC strip showed no corrosion after immersion in MMA solution for 30 hours, and a shrinkage rate of only 3% after 2 hours of high-temperature treatment at 120 degrees Celsius. Detailed Implementation

[0015] The present invention will be further described below with reference to embodiments: The present case will be clearly described in detail below. Any person skilled in the art who understands the embodiments of the present case can make changes and modifications based on the technology taught in the present case without departing from the spirit and scope of the present case.

[0016] Examples 1-4: A corrosion-resistant PVC strip for casting acrylic sheets, composed of the following components by weight, as shown in Table 1:

[0017] The inorganic filler in Example 1 is light calcium carbonate; the lubricant is a mixture of calcium stearate and stearic acid in a mass ratio of 1:1; the heat stabilizer is a mixture of barium stearate and zinc stearate in a mass ratio of 1:1; and the acrylonitrile content of the nitrile rubber is 20%. The inorganic filler in Example 2 is a mixture of light calcium carbonate and precipitated barium sulfate in a mass ratio of 3:2; the lubricant is stearic acid; the heat stabilizer is tris[2,4-di-tert-butylphenyl]phosphite; and the acrylonitrile content of the nitrile rubber is 35%. In Example 3, the inorganic filler was a mixture of light calcium carbonate and nano silica in a mass ratio of 4:1; the lubricant was a mixture of polyethylene wax and stearic acid in a mass ratio of 1:1; the heat stabilizer was a mixture of tris[2,4-di-tert-butylphenyl] phosphite and zinc stearate in a mass ratio of 1:1; and the acrylonitrile content of the nitrile rubber was 40%. The inorganic filler in Example 4 is a mixture of light calcium carbonate, precipitated barium sulfate, and nano silica in a mass ratio of 1:1:1; the lubricant is a mixture of polyethylene wax and calcium stearate in a mass ratio of 1:1; the heat stabilizer is a mixture of barium stearate and zinc stearate in a mass ratio of 1:1; and the acrylonitrile content of the nitrile rubber is 35%.

[0018] The corrosion-resistant PVC strips for casting acrylic sheets in the above embodiments are prepared by the following methods: Step 1: Add 100 parts of PVC resin with a degree of polymerization of 2500, 20-40 parts of trioctyl trimellitate, 35-55 parts of dibutyl phthalate, 3-8 parts of epoxidized soybean oil, and 5-10 parts of heat stabilizer to a high-speed mixer and stir for at least 2 minutes for initial mixing at a speed of 2500 r / min and a frequency of 45 Hz. Then add 5-10 parts of heat stabilizer and mix at high speed for at least 3 minutes at a speed of 2500 r / min and a frequency of 45 Hz. Step 2: Continue to add 10-30 parts of inorganic filler, 1-5 parts of lubricant, and 5-15 parts of nitrile rubber, and then knead at high speed for 4 minutes in a high-speed mixer at a speed of 2500 r / min and a frequency of 45 Hz. Step 3: When extruding using a single-screw extruder, the feeding zone temperature of the single-screw extruder is 145-150℃, and the temperatures of the four continuous temperature zones of the screw are set as follows: Zone 1 160-165℃, Zone 2 170-175℃, Zone 3 180-185℃, Zone 4 190-195℃, and the screw speed is 25-35 rpm. Step 4: Cool the extruded PVC strip with cooling water and then use a traction machine to pull the PVC strip.

[0019] Comparative Examples 1-2: A corrosion-resistant PVC strip for casting acrylic sheets, composed of the following components in parts by weight, as shown in Table 2:

[0021] The inorganic filler in Comparative Examples 1-2 is a mixture of light calcium carbonate and precipitated barium sulfate in a mass ratio of 3:2; the lubricant is stearic acid; the heat stabilizer is a mixture of barium stearate and zinc stearate in a mass ratio of 1:1; and the acrylonitrile content of the nitrile rubber is 35%. The preparation process of the corrosion-resistant PVC strips for casting acrylic sheets is the same as in the examples.

[0022] The corrosion-resistant PVC strips for cast acrylic sheets prepared in Examples 1-4 and Comparative Examples 1-2 were tested for performance. The testing methods were as follows: Each group of PVC strips was baked in an oven at 120℃ for 2 hours, and the dimensional shrinkage rate was measured. The PVC strips were then immersed in MMA solution for 30 hours, and the corrosion and cracking of the strips were observed. The test results are shown in Table 3.

[0023] As shown in Table 3, the PVC strips of Comparative Examples 1 and 2 exhibited shrinkage rates greater than 10%, and both corroded and cracked after immersion in MMA solution. The strips obtained in the examples all had shrinkage rates less than 10%, and none were corroded after immersion in MMA solution. The high-polymerization-degree resin powder effectively enhances intermolecular forces, which helps prevent the plasticizer and other additives from precipitating out of the MMA solution, thus preventing corrosion of the strips. The plasticizer TOTM has a large molecular weight, is resistant to migration and volatility, and has good compatibility with PVC, making it difficult to precipitate out. It also improves the toughness of the material, helping to reduce shrinkage.

[0024] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A corrosion-resistant PVC strip for casting acrylic sheets, characterized in that, Includes the following components in parts by weight: 100 parts of PVC resin with a degree of polymerization of 2500; Trioctyl trimellitate (TOTM) 20-40 parts; Dibutyl phthalate (DOP) 35-55 parts; Epoxidized soybean oil (ESO) 3-8 parts; 5-10 parts heat stabilizer; 10-30 parts of inorganic filler; 1-5 parts lubricant; 5-15 parts of nitrile rubber.

2. The corrosion-resistant PVC strip for casting acrylic sheets according to claim 1, characterized in that, The heat stabilizer is one or a mixture of several of barium stearate, zinc stearate, and tris[2,4-di-tert-butylphenyl]phosphite.

3. The corrosion-resistant PVC strip for casting acrylic sheets according to claim 1, characterized in that, The inorganic filler is selected from one or a mixture of several of the following: light calcium carbonate, precipitated barium sulfate, and nano-silica.

4. The corrosion-resistant PVC strip for casting acrylic sheets according to claim 1, characterized in that, The lubricant is one or a mixture of calcium stearate, polyethylene wax, and stearic acid.

5. The corrosion-resistant PVC strip for casting acrylic sheets according to claim 1, characterized in that, The acrylonitrile content of the nitrile rubber is 20%, 35%, or 40%.

6. A method for preparing the corrosion-resistant PVC strip for casting acrylic sheets as described in claim 1, characterized in that, Includes the following steps: Step 1: Add 100 parts of PVC resin with a degree of polymerization of 2500, 20-40 parts of trioctyl trimellitate, 35-55 parts of dibutyl phthalate, 3-8 parts of epoxidized soybean oil, and 5-10 parts of heat stabilizer to a high-speed mixer and stir for at least 2 minutes for initial mixing at a speed of 2500 r / min and a frequency of 45 Hz. Then add 5-10 parts of heat stabilizer and mix at high speed for at least 3 minutes at a speed of 2500 r / min and a frequency of 45 Hz. Step 2: Continue to add 10-30 parts of inorganic filler, 1-5 parts of lubricant, and 5-15 parts of nitrile rubber, and then knead at high speed for 4 minutes in a high-speed mixer at a speed of 2500 r / min and a frequency of 45 Hz. Step 3: Extrude using a single-screw extruder. The temperature in the feeding zone is 145-150℃, the temperature in screw zone 1 is 160-165℃, the temperature in screw zone 2 is 170-175℃, the temperature in screw zone 3 is 180-185℃, the temperature in screw zone 4 is 190-195℃, and the screw speed is 25-35 rpm. Step 4: Cool the extruded PVC strip with cooling water, and then use a traction machine to pull and wind the PVC strip.

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