A kind of solvent-free soft repairing cement and preparation method thereof

Abstract

The invention discloses a solvent-free soft repairing mortar and a preparation method thereof, wherein the solvent-free soft repairing mortar comprises component A and component B, wherein component A and component B are in a weight ratio of 100:4.5-10; wherein component A comprises the following components in parts by weight: 100 parts of polybutadiene, 0.8-3 parts of chain extender, 30-65 parts of polyvinyl chloride-vinyl acetate paste resin, 0-15 parts of carbon black, 0-15 parts of titanium dioxide, 0-3 parts of organic bentonite, 0-3 parts of white carbon black, and 0-15 parts of filler; and component B comprises solvent-free polydiisocyanate. The invention has the advantages of environmental protection, flame retardancy, fast curing speed at room temperature, high bonding strength, good corrosion resistance, good wear resistance, etc.; and solves the problems of slow curing speed, low bonding strength, easy peeling and delamination, poor corrosion resistance and wear resistance of the existing solvent-based repairing mortar.

Description

Technical Field

[0001] The invention relates to the technical field of rubber linings, and in particular to a solvent-free soft repairing cement and a preparation method thereof. Background Art

[0002] Anti-corrosion rubber linings and wear-resistant rubber linings are widely used in surface protection of equipment involving chemical corrosion and wear, such as power plant flue gas desulfurization, seawater desalination equipment, water treatment equipment, chemical equipment, steelmaking equipment, food manufacturing equipment, mineral processing equipment, nuclear power condensers and pipelines, etc.

[0003] During the manufacturing, installation and use of the lining, there may be local defects or damage. Repairing with room temperature curing mastic is the most appropriate method.

[0004] There are two main types of soft rubber lining repair mortars available on the domestic market. The first type is single-component or two-component polyurethane, and the second type is solvent-based rubber repair mortar. Existing polyurethane repair mortar has good wear resistance, but poor hydrolysis resistance, so it is rarely used to repair corrosion-resistant rubber linings. It also has great limitations in the repair of wear-resistant rubber linings, because there is water in the medium that many wear-resistant rubber linings contact. Existing solvent-based rubber repair mortars mainly include chlorosulfonated polyethylene repair mortar and chloroprene rubber repair mortar, which is to make a mixed rubber by refining chlorosulfonated polyethylene or chloroprene rubber composition, and then cut into small pieces, put into a high-speed mixer mixing barrel, add toluene, xylene and other solvents, and stir at high speed for at least 7 hours to make mortar. The disadvantages of this type of repair mortar are that the production process is long, there is solvent, the odor is large, it can be burned, and it is slow to cure at room temperature, and it takes at least 2 days to fully cure. The bonding strength with rubber linings and metals is not high, and it is easy to peel and delaminate during use. Therefore, in order to solve the above-mentioned problems existing in the prior art, the present invention comes from this. Summary of the invention

[0005] In view of at least one of the above problems existing in the prior art, the present invention provides a solvent-free soft repairing glue and a preparation method thereof.

[0006] To achieve the above objectives, one of the objectives of the present invention is to provide a solvent-free soft repairing glue, comprising component A and component B, wherein the weight ratio of component A to component B is 100:4.5-10;

[0007] Component A includes the following components in parts by weight: 100 parts of polybutadiene, 0.8 to 3 parts of chain extender, 30 to 65 parts of polyvinyl chloride-vinyl acetate paste resin, 0 to 15 parts of carbon black, 0 to 15 parts of titanium dioxide, 0 to 3 parts of organic bentonite, 0 to 3 parts of white carbon black, and 0 to 15 parts of filler;

[0008] Component B comprises a solvent-free polydiisocyanate.

[0009] The solvent-free soft repairing putty of the present invention can react quickly with the polybutadiene in component A and the chain extender and the polyisocyanate crosslinking agent in component B at room temperature or high temperature to generate a three-dimensional network solidified material. The main chain of polybutadiene makes the polymer have properties similar to those of polymers such as natural rubber and butyl rubber, and has excellent hydrolysis resistance, electrical insulation, acid and alkali resistance, wear resistance, low temperature resistance, aging resistance, and good adhesion to non-polar and low-polar materials. The content of vinyl acetate in the polyvinyl chloride-vinyl acetate paste resin is 5% to 12%. Since flexible vinyl acetate is introduced into the rigid molecular chain segment of PVC, the polarity of PVC molecules is weakened, the attraction between molecules is reduced, and thus the gelation temperature is significantly reduced, and low-temperature gel curing can be achieved. At the same time, the introduction of the ester group also improves the adhesion between PVC and various adhesive substrates.

[0010] Preferably, the hardness of the solvent-free soft repair glue is Shore A: 50-85. It can quickly undergo cross-linking reaction and chain extension reaction at room temperature of 23°C, and can be fully cross-linked and cured in 4-12 hours to form a three-dimensional network solidified product. It has good corrosion resistance and wear resistance, and good adhesion to rubber and metal.

[0011] Preferably, the chain extender comprises the following components in parts by weight: 0-25 parts of low molecular weight polyol, 25-50 parts of castor oil and 50-60 parts of polyethylene powder, and is prepared into a paste. The paste is easy to be evenly dispersed into other components in component A. The hydroxyl groups of the low molecular weight polyol and castor oil can participate in the chain extension reaction, increase the length of the polymer molecular chain, increase the molecular weight, improve the tensile strength, and reduce the hardness.

[0012] Another object of the present invention is to provide a method for preparing a solvent-free soft repair mortar, wherein the method for preparing component A comprises the following steps:

[0013] Step 1: Add polybutadiene and chain extender into a mixing barrel of a low-speed mixer according to the formula ratio and stir evenly at a stirring speed of 50 to 100 rpm for at least 15 minutes;

[0014] Step 2, adding carbon black, titanium dioxide, organic bentonite, white carbon black and filler according to the formula ratio, stirring evenly, stirring at a speed of 50 to 100 rpm, and stirring for at least 30 minutes;

[0015] Step 3: Add polyvinyl chloride-vinyl acetate paste resin according to the formula ratio, stir evenly at a stirring speed of 50 to 100 rpm for at least 1.5 hours to obtain component A.

[0016] After the stirring time reaches the specified time in step 3, stop stirring, lift the stirring paddle, use a scraper to scrape the clay on the paddle and the wall of the mixing barrel, and visually inspect the uniformity of the clay. If the clay is fine, has a uniform viscosity, and has no powdery undispersed matter, it can be determined that it has been stirred evenly. Pour the clay into a packaging iron barrel, seal it and store it in a cool and dry place. When using, pack it in a 1 liter or 0.5 liter iron box, and add component B to component A and mix evenly.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] The solvent-free soft repairing putty of the present invention can react quickly with the polybutadiene in component A and the chain extender and the polyisocyanate crosslinking agent in component B at room temperature or high temperature to generate a three-dimensional network solidified material. The main chain of polybutadiene makes the polymer have properties similar to those of polymers such as natural rubber and butyl rubber, and has excellent hydrolysis resistance, electrical insulation, acid and alkali resistance, wear resistance, low temperature resistance, aging resistance, and good adhesion to non-polar and low-polar materials. The content of vinyl acetate in the polyvinyl chloride-vinyl acetate paste resin is 5% to 12%. Since flexible vinyl acetate is introduced into the rigid molecular chain segment of PVC, the polarity of PVC molecules is weakened, the attraction between molecules is reduced, and thus the gelation temperature is significantly reduced, and low-temperature gel curing can be achieved. At the same time, the introduction of the ester group also improves the adhesion between PVC and various adhesive substrates. The repair glue of the present invention has the advantages of being environmentally friendly, flame retardant, fast curing speed at room temperature, high bonding strength, good corrosion resistance, good wear resistance, etc. It solves the problems of slow curing speed, low bonding strength, easy peeling and delamination, poor corrosion resistance and wear resistance of existing solvent-based repair glue. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0020] A solvent-free soft repair mortar provided in an embodiment of the present invention comprises component A and component B, wherein the weight ratio of component A to component B is 100:4.5-10; wherein component A comprises the following components in parts by weight: 100 parts of polybutadiene, 0.8 to 3 parts of a chain extender, 30 to 65 parts of a polyvinyl chloride-vinyl acetate paste resin, 0 to 15 parts of carbon black, 0 to 15 parts of titanium dioxide, 0 to 3 parts of organic bentonite, 0 to 3 parts of white carbon black, and 0 to 15 parts of a filler; and component B comprises a solvent-free polydiisocyanate.

[0021] The present invention provides a method for preparing a solvent-free soft repairing mortar, wherein the method for preparing component A comprises the following steps:

[0022] Step 1: Add polybutadiene and chain extender into a mixing barrel of a low-speed mixer according to the formula ratio and stir evenly at a stirring speed of 50 to 100 rpm for at least 15 minutes;

[0023] Step 2, adding carbon black, titanium dioxide, organic bentonite, white carbon black and filler according to the formula ratio, stirring evenly, stirring at a speed of 50 to 100 rpm, and stirring for at least 30 minutes;

[0024] Step 3: Add polyvinyl chloride-vinyl acetate paste resin according to the formula ratio, stir evenly at a stirring speed of 50 to 100 rpm for at least 1.5 hours to obtain component A.

[0025] Table 1 Proportion of component A of the solvent-free soft repairing glue of the present invention

[0026]

[0027] According to the preparation method of component A, component A1, component A2, component A3, component A4, component A5, component A6 and component A7 are prepared for later use.

[0028] Table 2 Test data of hardness, tensile strength, elongation at break, adhesion to metal, and adhesion to natural rubber of soft repair cement samples (Y1 to Y7) made by mixing component A (A1 to A7) and component B

[0029]

[0030] Table 3 Test data of hardness, tensile strength, elongation at break, adhesion to metal, and adhesion to natural rubber of soft repair cement samples (Y1 to Y7) made by mixing component A (A1 to A7) and component B

[0031]

[0032] The above shows and describes the basic principle, main features, basic ratio of component A, and basic ratio of component A to component B of the present invention. By changing the weight of component A and the ratio of component B, the curing speed and the hardness of the product can be changed. Various raw materials required by the present invention can be purchased on the market.

[0033] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

[0034] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A solvent-free soft repair mortar, characterized in that: Comprising component A and component B, wherein the weight ratio of component A to component B is 100:4.5-10; Wherein, component A comprises the following components in parts by weight: 100 parts of polybutadiene, 0.8-3 parts of chain extender, 30-65 parts of polyvinyl chloride-vinyl acetate paste resin, 0-15 parts of carbon black, 0-15 parts of titanium dioxide, 0-3 parts of organic bentonite, 0-3 parts of white carbon black, and 0-15 parts of filler, wherein the filler comprises one or more of clay, barium sulfate, and talc; Component B includes a solvent-free polydiisocyanate; The polybutadiene is a solvent-free polybutadiene polymer, and the polybutadiene polymer is a composition of one or more hydroxyl-terminated polybutadienes, with a relative molecular weight of 2100-3200, a hydroxyl value of 0.5-0.9 mmol / g, and a viscosity of 4.5-7.0 Pa•s.

2. The solvent-free soft repair mortar according to claim 1, characterized in that: The hardness of the solvent-free soft repairing mortar is Shore A: 50-85.

3. The solvent-free soft repair mortar according to claim 1, characterized in that: The content of vinyl acetate in the polyvinyl chloride-vinyl acetate paste resin is 5% to 12%.

4. The solvent-free soft repair mortar according to claim 1, characterized in that: The chain extender comprises the following components in parts by weight: 0-25 parts of low molecular weight polyol, 25-50 parts of castor oil and 50-60 parts of polyethylene powder, and is prepared into a paste.

5. The solvent-free soft repair mortar according to claim 1, characterized in that: The solvent-free polydiisocyanate of component B has an isocyanate content of ≥25% and a viscosity of 90 mPa•s at 25°C.

6. The solvent-free soft repair cement according to claim 1, characterized in that: When the solvent-free soft repairing glue is used, component B is added to component A and mixed evenly, and then applied to the rubber lining to be repaired, and a cross-linking reaction and a chain extension reaction are rapidly carried out at room temperature to generate a three-dimensional network solidified product.

7. The solvent-free soft repair mortar according to claim 1, characterized in that: The solvent-free soft repairing cement is used for repairing soft anti-corrosion rubber linings and wear-resistant rubber linings.

8. A method for preparing the solvent-free soft repairing mortar according to any one of claims 1 to 7, characterized in that: The preparation method of component A comprises the following steps: Step 1: Add polybutadiene and chain extender into the mixing barrel of a low-speed mixer according to the formula ratio and stir evenly at a stirring speed of 50-100 rpm for at least 15 minutes; Step 2: Add carbon black, titanium dioxide, organic bentonite, white carbon black and filler according to the formula ratio, stir evenly, the stirring speed is 50-100 rpm, and the stirring time is at least 30 minutes; Step 3: Add polyvinyl chloride-vinyl acetate paste resin according to the formula ratio, stir evenly at a stirring speed of 50 to 100 rpm for at least 1.5 hours to obtain component A.

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