CN115197659B - Preparation method of pre-reaction solution for adhesive containing hydrotalcite compound - Google Patents

Abstract

The present invention provides a method for preparing a pre-reaction solution for an adhesive containing a hydrotalcite composite. The pre-reaction solution uses magnesium nitrate and aluminum nitrate to prepare magnesium-aluminum hydrotalcite, and then prepares a laminated hydrotalcite-sodium phenate compound. A hydrotalcite-sodium phenate compound is first coated on the surface of magnesium oxide particles, and then the large molecular weight p-tert-butylphenol formaldehyde resin can be adsorbed on the surface of magnesium oxide particles, so that the magnesium oxide particles in the pre-reaction solution are suspended in the solution Neutralization is not easy to coagulate with each other to form precipitates, thereby preventing the solid-liquid stratification of the pre-reaction solution. The pre-reaction liquid prepared by the invention can be applied to prepare the adhesive of chlorinated rubber, and improve the adhesive force, heat resistance and storage stability of the adhesive. The pre-reaction liquid is easy to prepare and is suitable for popularization and application.

Description

Method for preparing pre-reaction liquid for adhesive containing hydrotalcite composite

Technical field:

The invention provides a pre-reaction liquid for an adhesive containing a hydrotalcite compound and also provides a method for preparing the pre-reaction liquid, belonging to the technical field of chlorinated rubber adhesives.

Background technology:

Chlorinated rubber adhesive is one of the adhesive varieties commonly used in material bonding. Pre-reaction liquid needs to be added during the preparation of chlorinated rubber adhesive. Pre-reaction liquid with good performance can significantly improve the adhesion of adhesive to the surface of materials (such as glass, metal, cloth, etc.) and improve the high-temperature bonding performance of adhesive. Pre-reaction liquid is generally obtained by reacting magnesium oxide solid powder and tert-butyl phenolic resin. However, in production, storage and application, the pre-reaction liquid often encounters the phenomenon of phase separation, that is, the pre-reaction liquid undergoes solid-liquid stratification (Document 1: Chen Denglong, How to overcome the stratification phenomenon of chloroprene rubber adhesive pre-reaction liquid and the remedy after stratification, "China Adhesives", 2003, 12 (2), 38-40). The solid-liquid stratification of the pre-reaction liquid not only reduces the performance of the adhesive product, but also brings many inconveniences to users. At the same time, due to the inhomogeneity of appearance, the white precipitation at the bottom of the barrel also causes users to distrust the manufacturer, thereby affecting its market sales. The main reason for the solid-liquid stratification phenomenon in the pre-reaction liquid is that the polar low molecular weight resin contained in the phenolic resin will be preferentially adsorbed on the surface of the magnesium oxide particles, thereby preventing the formation of a thick chlorinated rubber adsorption layer on the suspended magnesium oxide particles, or the chlorinated rubber adsorbed on the surface of the magnesium oxide particles will be replaced by these low molecular weight resins, and the molecular chain length of these low molecular weight resins is not enough to form a sufficiently thick adsorption layer on the surface of the magnesium oxide particles, so that the magnesium oxide suspended particles lose stability and gradually produce flocculent precipitation, and finally produce solid-liquid stratification phenomenon (Document 2: Guo Jizhong, Phenolic Resin for Chloroprene Adhesives, "Adhesives", 1983, 2(7), 23-31).

Summary of the invention:

In order to solve the problems existing in the prior art, the present invention provides a pre-reaction liquid for chlorinated rubber adhesive, which is not prone to solid-liquid stratification.

Another object of the present invention is to provide a method for preparing a pre-reaction liquid for a chlorinated rubber adhesive, which is simple, has readily available raw materials, and is easy to promote and apply in the market.

The present invention also provides application of the pre-reaction liquid for chlorinated rubber adhesive in the adhesive field.

The specific technical solutions of the present invention are as follows:

A pre-reaction liquid for chlorinated rubber adhesive, the preparation steps of which are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 7.0-10.0 with an alkali solution under stirring conditions at a speed of 100-1000 r/min, and then the mixture is reacted for 0.5-3 h under nitrogen protection and stirring conditions at a speed of 500-1500 r/min, the resulting mixture is placed in a closed reactor and reacted at 70-120°C for 2-24 h, the resulting mixture is filtered, and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for later use;

(2) Mixing the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed at room temperature, and then reacting for 10-48 hours under nitrogen protection and stirring at a speed of 200-1200 r/min, filtering the obtained product, and washing it with distilled water from which carbon dioxide has been removed until the filtrate is neutral, drying the filtered precipitate at 80-115° C. for 10-48 hours, and grinding the dried solid into a (300-500) mesh white hydrotalcite-sodium phenolate composite powder for later use;

(3) adding the hydrotalcite-sodium phenolate complex powder prepared in step (2) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the resulting mixture to reflux reaction at 45-70° C. and stirring at a speed of 200-3000 r/min for 3-6 hours, and then allowing to stand for 12-36 hours to obtain a solution containing a magnesium oxide-hydrotalcite-sodium phenolate complex;

(4) Adding p-tert-butylphenol formaldehyde resin to the solution containing the magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3), and reflux the resulting mixture at 25-60°C and at a stirring speed of 200-1200 r/min for 6-10 hours to obtain a pre-reaction solution for chlorinated rubber adhesive.

The further design of the present invention is:

The alkali solution in step (1) is 5-25wt% NaOH solution.

In step (1), the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water for removing carbon dioxide is (1-1.06):(0.32-0.43):(15-30).

The weight ratio of the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed is 1:(0.22-0.46):(5-14) in step (2).

The weight ratio of the hydrotalcite-sodium phenolate composite powder prepared in step (2) described in step (3), magnesium oxide, ethyl acetate and cyclohexane is (0.5-1.5): (2-3.8): (1.2-2): (20-38).

The weight ratio of the solution containing the magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) described in step (4) to the p-tert-butylphenol formaldehyde resin is (24-46):(22-40).

The present invention also provides a pre-reaction liquid for chlorinated rubber adhesive and application of the pre-reaction liquid in chlorinated rubber adhesive.

Compared with the prior art, the working principle and advantages of the present invention are as follows:

Step 1 of the present invention is to prepare a layered magnesium aluminum hydrotalcite using aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed as raw materials, wherein the molecular formula of the hydrotalcite is [Mg _1-x Al _x (OH) ₂ ](NO ₃ ) _x , where x is 0.17-0.22. The hydrotalcite is based on the structure of brucite [Mg(OH) ₂ ], and the Mg ²⁺ in the unit layer formed by the shared edge of the MgO ₆ octahedron can be isomorphously replaced by Al ³⁺ within a certain range, so that the layer plate is positively charged, and there is exchangeable NO ₃ ^- between the layers to balance the positive charge on the layer plate, so that the overall structure of the hydrotalcite is electrically neutral. The surface of the inorganic layer of magnesium-aluminum hydrotalcite is positively charged, and the metal ions at the edge of the inorganic layer of hydrotalcite are in an unsaturated coordination state, which has strong activity, and the flat hydroxyl groups at the edge of the hydrotalcite layer are easy to provide electrons, which is conducive to attracting other positively charged particles around (Document 3: Zhou Yinghui et al., Theoretical Study on the Adsorption of Azo Dye Acid Orange in Hydrotalcite Interlayers, "Industrial Catalysis", 2008, 16 (10), 180-183). In this hydrotalcite structure, the interaction between nitrate ions and inorganic layers is weak, so the nitrate ions between the layers can undergo interlayer exchange reactions with other ions and molecules to form a new interlayer structure composite, which will have different physical and chemical properties from the original hydrotalcite compound.

The step 2 of the present invention is to make the hydrotalcite-sodium phenolate complex by interlayer ion exchange reaction between the magnesium aluminum hydrotalcite with nitrate ions embedded between the inorganic layers prepared in step 1 and sodium phenolate. Sodium phenolate can ionize negatively charged phenolate ions in aqueous solution. The volume of phenolate ions is much larger than nitrate ions. When phenolate ions are embedded between the hydrotalcite layers, the spacing between the hydrotalcite layers is increased, and the specific surface area of the hydrotalcite inorganic layers is also expanded, exposing more active sites. In addition, phenol anions are adsorbed on the surface of the hydrotalcite layers, and the hydrophilic surface of the hydrotalcite inorganic layers is modified into a hydrophobic surface, so that the hydrotalcite layers are easily dispersed in the hydrophobic mixed organic solvent formed by ethyl acetate and cyclohexane; otherwise, the hydrotalcite inorganic layers with unmodified strong hydrophilicity on the surface will cause polymerization and precipitation between the hydrotalcite particles in the hydrophobic organic solvent because the two properties are completely opposite.

Step 3 of the present invention is to react the hydrotalcite-sodium phenolate complex obtained in step 2 with magnesium oxide (active light magnesium oxide) particles. Active light magnesium oxide has high activity, and the particle surface easily absorbs moisture in the environment to form a magnesium hydroxide layer, and the surface of the magnesium hydroxide layer is positively charged (Document 4: Zhang Dongsheng. Research on Surface Modification of Magnesium Hydroxide [D]. Shaanxi: Xi'an University of Electronic Science and Technology, 2013). Therefore, the electron-donating hydroxyl groups at the edge of the hydrotalcite inorganic layer in the hydrotalcite-sodium phenolate complex interact with the positively charged surface of the active light magnesium oxide particles, thus forming a magnesium oxide-hydrotalcite-sodium phenolate complex, in which the magnesium oxide particles are coated by the hydrotalcite-sodium phenolate complex, so that these independent magnesium oxide particles are not easy to agglomerate and precipitate.

The fourth step of the present invention is to react the magnesium oxide-hydrotalcite-sodium phenolate complex obtained in the third step with p-tert-butylphenol formaldehyde resin. When adding 4-tert-butylphenol formaldehyde resin, the migration speed of 4-tert-butylphenol formaldehyde resin with small molecular weight will be faster than that of 4-tert-butylphenol formaldehyde resin with large molecular weight due to its small molecular chain. Therefore, these 4-tert-butylphenol formaldehyde resins with small molecular weight will first contact the hydrotalcite-sodium phenolate complex wrapped outside the magnesium oxide particles. Since these 4-tert-butylphenol formaldehyde resins with small molecular weight also contain the same phenol group as that in the hydrotalcite-sodium phenolate complex, according to the principle of like attracts like, these 4-tert-butylphenol formaldehyde resins with small molecular weight will be adsorbed by the hydrotalcite-sodium phenolate complex lamellae, which causes the molecular weight loaded by the lamellae of the hydrotalcite-sodium phenolate complex to be too large, thereby weakening the interaction between the hydrotalcite-sodium phenolate complex and the magnesium oxide surface, that is, the hydrotalcite-sodium phenolate complex will detach from the magnesium oxide particle surface, thereby exposing the active sites on the magnesium oxide surface; at this time, the molecular weight Large p-tert-butylphenol formaldehyde resins will replace the hydrotalcite-sodium phenolate complex and react with the surface of magnesium oxide, that is, these large molecular weight p-tert-butylphenol formaldehyde resins replace the hydrotalcite-sodium phenolate complex and wrap on the surface of magnesium oxide particles, thereby forming a sufficiently thick large molecular weight p-tert-butylphenol formaldehyde resin adsorption layer on the surface of magnesium oxide particles. The large molecular weight p-tert-butylphenol formaldehyde resin has excellent suspension properties, thereby allowing the magnesium oxide particles to be suspended in the solution and maintain sufficient stability.

In the pre-reaction liquid prepared by the present invention, due to the presence of the hydrotalcite-sodium phenolate complex, the low molecular weight resin contained in the p-tert-butylphenol formaldehyde resin cannot be preferentially adsorbed on the surface of the magnesium oxide particles, and finally the large molecular weight p-tert-butylphenol formaldehyde resin is adsorbed on the surface of the magnesium oxide particles. The large molecular weight p-tert-butylphenol formaldehyde resin has good suspension properties and can suspend the coated magnesium oxide particles in the solution. The magnesium oxide particles are also separated by these large molecular weight resins, which prevents the magnesium oxide particles from agglomerating with each other to form precipitation, thereby preventing the pre-reaction liquid from generating a solid-liquid stratification phenomenon.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention.

FIG. 1 is a flow chart of a process for preparing a pre-reaction solution for a chlorinated rubber adhesive according to the present invention.

FIG2 is an X-ray powder diffraction pattern of the sample; in FIG2 a is a sample of the colloid prepared in step (1) of Example 3 after drying, and b is a hydrotalcite-sodium phenolate composite powder prepared in step (2) of Example 3 of the present invention.

DETAILED DESCRIPTION

The chemical raw materials used in the following embodiments: sodium phenol comes from Jining Chengtai Chemical Co., Ltd.; the chlorinated rubber used is produced by Jiangsu Ruihe New Material Co., Ltd., and CR600 type chlorinated rubber is used; the magnesium oxide used is the active light magnesium oxide produced by Japan Shendao Chemical Co., Ltd., and the product model is 150; the p-tert-butylphenol formaldehyde resin used is produced by Jinan Shanhai Chemical Technology Co., Ltd., and the product model is 2402; the antioxidant 264 comes from Zhengzhou Piney Chemical Reagent Factory; 120# solvent oil comes from Lanzhou Petrochemical Co., Ltd.; other chemical reagents are all commercially available, chemically pure reagents.

Example 1

A pre-reaction liquid for chlorinated rubber adhesive, the preparation steps of which are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 7.0 with an alkali solution under a stirring condition of a rotation speed of 100 r/min, and then the mixture is reacted for 0.5 h under nitrogen protection and a stirring condition of a rotation speed of 500 r/min. The resulting mixture is placed in a closed reactor and reacted at 70°C for 2 h. The resulting mixture is filtered and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for standby use; the alkali solution in step (1) is a 5wt% NaOH solution, and the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water from which carbon dioxide has been removed in step (1) is 1:0.32:15;

(2) Mixing the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed at room temperature, and then reacting the mixture for 10 hours under nitrogen protection and stirring at a speed of 200 r/min, filtering the obtained product and washing it with distilled water from which carbon dioxide has been removed until the filtrate is neutral, drying the filtered precipitate at 80° C. for 10 hours, and grinding the dried solid into a 300-mesh white hydrotalcite-sodium phenolate composite powder for later use; The weight ratio of the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed described in step (2) is 1:0.22:5;

(3) adding the hydrotalcite-sodium phenolate complex powder prepared in step (2) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 45°C and stirring at a speed of 200 r/min for 3 hours, and then standing for 12 hours to obtain a solution containing a magnesium oxide-hydrotalcite-sodium phenolate complex; the weight ratio of the hydrotalcite-sodium phenolate complex powder prepared in step (2), magnesium oxide, ethyl acetate and cyclohexane in step (3) is 0.5:2:1.2:20;

(4) Adding 4-tert-butylphenol formaldehyde resin to the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3), and reflux the resulting mixture at 25°C and 200 r/min for 6 hours to obtain a pre-reaction liquid for chlorinated rubber adhesive; the weight ratio of the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) and 4-tert-butylphenol formaldehyde resin is 24:22.

Example 2

A pre-reaction liquid for chlorinated rubber adhesive, the preparation steps of which are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 8.0 with an alkali solution under a stirring condition of a rotation speed of 300 r/min, and then the mixture is reacted for 1 hour under the protection of nitrogen and a stirring condition of a rotation speed of 700 r/min. The resulting mixture is placed in a closed reactor and reacted at 80°C for 7 hours, the resulting mixture is filtered, and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for standby use; the alkali solution in step (1) is a 10wt% NaOH solution, and the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water from which carbon dioxide has been removed in step (1) is 1.02:0.34:18;

(2) Mixing the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed at room temperature, and then reacting the mixture for 20 hours under nitrogen protection and stirring at a speed of 500 r/min, filtering the obtained product and washing it with distilled water from which carbon dioxide has been removed until the filtrate is neutral, drying the filtered precipitate at 90° C. for 20 hours, and grinding the dried solid into a 300-mesh white hydrotalcite-sodium phenolate composite powder for later use; The weight ratio of the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed described in step (2) is 1:0.28:7;

(3) adding the hydrotalcite-sodium phenolate complex powder prepared in step (2) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 50°C and stirring at a speed of 1000 r/min for 3 hours, and then standing for 18 hours to obtain a solution containing a magnesium oxide-hydrotalcite-sodium phenolate complex; the weight ratio of the hydrotalcite-sodium phenolate complex powder prepared in step (2), magnesium oxide, ethyl acetate and cyclohexane in step (3) is 0.75:2.4:1.4:25;

(4) Adding 4-tert-butylphenol formaldehyde resin to the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3), and reflux the resulting mixture at 35°C and 500 r/min for 7 hours to obtain a pre-reaction liquid for chlorinated rubber adhesive; the weight ratio of the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) and 4-tert-butylphenol formaldehyde resin is 29:27.

Example 3

A pre-reaction liquid for chlorinated rubber adhesive, the preparation steps of which are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 9.5 with an alkali solution under a stirring condition of a rotation speed of 550 r/min, and then the mixture is reacted for 2 hours under nitrogen protection and a stirring condition of a rotation speed of 1000 r/min. The resulting mixture is placed in a closed reactor and reacted at 100°C for 24 hours. The resulting mixture is filtered and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for standby use; the alkali solution in step (1) is a 15wt% NaOH solution, and the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water from which carbon dioxide has been removed in step (1) is 1.04:0.37:22;

(2) Mixing the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed at room temperature, and then reacting the mixture for 30 hours under nitrogen protection and stirring at a speed of 800 r/min, filtering the obtained product and washing it with distilled water from which carbon dioxide has been removed until the filtrate is neutral, drying the filtered precipitate at 100° C. for 30 hours, and grinding the dried solid into a 500-mesh white hydrotalcite-sodium phenolate composite powder for later use; The weight ratio of the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed described in step (2) is 1:0.34:10;

(3) adding the hydrotalcite-sodium phenolate complex powder prepared in step (2) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 56°C and stirring at a speed of 1700 r/min for 5 hours, and then standing for 24 hours to obtain a solution containing a magnesium oxide-hydrotalcite-sodium phenolate complex; the weight ratio of the hydrotalcite-sodium phenolate complex powder prepared in step (2), magnesium oxide, ethyl acetate and cyclohexane in step (3) is 1:2.9:1.6:29;

(4) adding p-tert-butylphenol formaldehyde resin to the solution containing the magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3), and subjecting the resulting mixture to reflux reaction at 50°C and a stirring speed of 700 r/min for 8 hours to obtain a pre-reaction liquid for a chlorinated rubber adhesive; the weight ratio of the solution containing the magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) and the p-tert-butylphenol formaldehyde resin is 35:31.

管压40.0kV,管流30.0mA)，试验结果如附图2所示。The samples prepared in steps (1) and (2) of this embodiment were subjected to X-ray powder diffraction analysis. The X-ray powder diffraction was performed on a Rigaku D/MAX X-ray diffractometer using CuKα (

The tube voltage is 40.0 kV, the tube current is 30.0 mA), and the test results are shown in Figure 2.

In the accompanying drawing 2, a is the powder of the colloid prepared in step (1) of Example 3 after drying at 100°C for 48 hours, and b is the powder of the hydrotalcite-sodium phenolate complex prepared in step (2) of Example 3. The sample of the colloid prepared in step (1) of Example 3 after drying is a characteristic X-ray diffraction spectrum of magnesium-aluminum hydrotalcite, and the first diffraction peak of the X-ray powder diffraction pattern represents the interlaminar spacing between adjacent layers of hydrotalcite. Compared with the powder sample of the colloid prepared in step (1) of Example 3 after drying, the first diffraction peak of the X-ray powder diffraction of the hydrotalcite-sodium phenolate complex prepared in Example 3 moves toward the small-angle diffraction direction, indicating that phenolate ions have been embedded between the hydrotalcite layers in the hydrotalcite-sodium phenolate complex.

Example 4

A pre-reaction liquid for chlorinated rubber adhesive, the preparation steps of which are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 9.0 with an alkali solution under a stirring condition of a rotation speed of 750 r/min, and then the mixture is reacted for 2.5 hours under nitrogen protection and a stirring condition of a rotation speed of 1300 r/min, the resulting mixture is placed in a closed reactor and reacted for 12 hours at 90°C, the resulting mixture is filtered, and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for standby use; the alkali solution in step (1) is a 20wt% NaOH solution, and the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water from which carbon dioxide has been removed in step (1) is 1.05:0.4:26;

(2) Mixing the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed at room temperature, and then reacting for 40 hours under nitrogen protection and stirring at a speed of 1000 r/min, filtering the obtained product and washing it with distilled water from which carbon dioxide has been removed until the filtrate is neutral, drying the filtered precipitate at 108° C. for 40 hours, and grinding the dried solid into a 500-mesh white hydrotalcite-sodium phenolate composite powder for standby use; The weight ratio of the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed described in step (2) is 1:0.4:12;

(3) adding the hydrotalcite-sodium phenolate complex powder prepared in step (2) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 64°C and stirring at a speed of 2200 r/min for 4 hours, and then standing for 30 hours to obtain a solution containing a magnesium oxide-hydrotalcite-sodium phenolate complex; the weight ratio of the hydrotalcite-sodium phenolate complex powder prepared in step (2), magnesium oxide, ethyl acetate and cyclohexane in step (3) is 1.25:3.4:1.8:33;

(4) Adding 4-tert-butylphenol formaldehyde resin to the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3), and reflux the resulting mixture at 55°C and at a stirring speed of 1000 r/min for 9 hours to obtain a pre-reaction liquid for chlorinated rubber adhesive; the weight ratio of the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) and 4-tert-butylphenol formaldehyde resin is 41:36.

Example 5

A pre-reaction liquid for chlorinated rubber adhesive, the preparation steps of which are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 10.0 with an alkali solution under a stirring condition of a rotation speed of 1000 r/min, and then the mixture is reacted for 3 hours under nitrogen protection and a stirring condition of a rotation speed of 1500 r/min. The resulting mixture is placed in a closed reactor and reacted for 18 hours at 120°C, the resulting mixture is filtered, and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for standby use; the alkali solution in step (1) is a 25wt% NaOH solution, and the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water from which carbon dioxide has been removed in step (1) is 1.06:0.43:30;

(2) Mixing the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed at room temperature, and then reacting for 48 hours under nitrogen protection and stirring at a speed of 1200 r/min, filtering the obtained product, and washing it with distilled water from which carbon dioxide has been removed until the filtrate is neutral, drying the filtered precipitate at 115° C. for 48 hours, and grinding the dried solid into a 400-mesh white hydrotalcite-sodium phenolate composite powder for standby use; The weight ratio of the colloid obtained in step 1, sodium phenolate and distilled water from which carbon dioxide has been removed described in step (2) is 1:0.46:14;

(3) adding the hydrotalcite-sodium phenolate complex powder prepared in step (2) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 70°C and stirring at a speed of 3000 r/min for 6 hours, and then standing for 36 hours to obtain a solution containing a magnesium oxide-hydrotalcite-sodium phenolate complex; the weight ratio of the hydrotalcite-sodium phenolate complex powder prepared in step (2), magnesium oxide, ethyl acetate and cyclohexane in step (3) is 1.5:3.8:2:38;

(4) Adding 4-tert-butylphenol formaldehyde resin to the solution containing the magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3), and subjecting the resulting mixture to reflux reaction at 60°C and a stirring speed of 1200 r/min for 10 hours to obtain a pre-reaction liquid for a chlorinated rubber adhesive; the weight ratio of the solution containing the magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) and the 4-tert-butylphenol formaldehyde resin is 46:40.

Comparative Example 6

This example is to illustrate the effect of the hydrotalcite-sodium phenolate complex on the performance of the pre-reaction liquid. In the preparation process, only hydrotalcite is used, and no sodium phenolate is used. That is, compared with Example 3, this example does not have step (2) of Example 3, and the preparation process does not involve the preparation of the hydrotalcite-sodium phenolate complex. The other preparation steps and reagent dosages are the same as those in Example 3. The specific test steps are as follows:

(1) Aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water from which carbon dioxide has been removed are mixed and stirred at room temperature, the pH of the resulting mixture is adjusted to 9.5 with an alkali solution under a stirring condition of a rotation speed of 550 r/min, and then the mixture is reacted for 2 hours under nitrogen protection and a stirring condition of a rotation speed of 1000 r/min. The resulting mixture is placed in a closed reactor and reacted at 100°C for 24 hours. The resulting mixture is filtered and washed with distilled water from which carbon dioxide has been removed until the filtrate is neutral, and the filtered colloid is used for standby use; the alkali solution in step (1) is a 15wt% NaOH solution, and the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and water from which carbon dioxide has been removed in step (1) is 1.04:0.37:22;

(2) adding the colloid prepared in step (1) and magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 56°C and stirring at a speed of 1700 r/min for 5 hours, and then standing for 24 hours to obtain a solution containing colloid and magnesium oxide, wherein the weight ratio of the colloid prepared in step (1), magnesium oxide, ethyl acetate and cyclohexane in step (2) is 1:2.9:1.6:29;

(3) adding p-tert-butylphenol formaldehyde resin to the solution containing colloid and magnesium oxide prepared in step (2), and reflux the resulting mixture at 50°C and 700 r/min for 8 hours to obtain a mixed solution, wherein the weight ratio of the solution containing colloid and magnesium oxide prepared in step (2) to p-tert-butylphenol formaldehyde resin is 35:31.

Comparative Example 7

This example is to illustrate the effect of the hydrotalcite-sodium phenolate complex on the performance of the pre-reaction liquid. No hydrotalcite or sodium phenolate is used in the preparation process. Compared with Example 3, this example does not include step (1) and step (2) of Example 3 and does not involve the preparation of the hydrotalcite-sodium phenolate complex. The other preparation steps and reagent dosages are the same as those in Example 3. The specific test steps are as follows:

(1) adding magnesium oxide to a mixed solvent of ethyl acetate and cyclohexane, and subjecting the obtained mixture to reflux reaction at 56°C and stirring at a speed of 1700 r/min for 5 hours, and then standing for 24 hours to obtain a solution containing magnesium oxide; in step (1), the weight ratio of magnesium oxide, ethyl acetate and cyclohexane is 2.9:1.6:29;

(2) adding p-tert-butylphenol formaldehyde resin to the magnesium oxide-containing solution prepared in step (1), and subjecting the resulting mixture to reflux reaction at 50°C and a stirring speed of 700 r/min for 8 hours to obtain a pre-reaction liquid for chlorinated rubber adhesive; the weight ratio of the magnesium oxide-containing solution prepared in step (1) to the p-tert-butylphenol formaldehyde resin is 35:31.

Comparative Example 8

This example is to illustrate the effect of the magnesium oxide-hydrotalcite-sodium phenolate complex on the performance of the pre-reaction solution. Compared with Example 3, the preparation process of this example does not involve the preparation of the magnesium oxide-hydrotalcite-sodium phenolate complex. Only the hydrotalcite-sodium phenolate complex powder and magnesium oxide are physically mixed at room temperature. The other preparation steps and reagent dosages are the same as those in Example 3. The specific test steps are as follows:

Steps (1) and (2) of this embodiment are the same as steps (1) and (2) of embodiment 3.

(3) adding the hydrotalcite-sodium phenolate complex powder and magnesium oxide prepared in step (2) to a mixed solvent of ethyl acetate and cyclohexane at room temperature to obtain a solution containing the hydrotalcite-sodium phenolate complex and magnesium oxide, wherein the weight ratio of the hydrotalcite-sodium phenolate complex powder prepared in step (2), magnesium oxide, ethyl acetate and cyclohexane in step (3) is 1:2.9:1.6:29;

(4) Adding p-tert-butylphenol formaldehyde resin to the solution containing the hydrotalcite-sodium phenolate complex and magnesium oxide obtained in step (3), and subjecting the resulting mixture to reflux reaction at 50°C and a stirring speed of 700 r/min for 8 hours to obtain a pre-reaction liquid for a chlorinated rubber adhesive, wherein the weight ratio of the solution containing the hydrotalcite-sodium phenolate complex and magnesium oxide prepared in step (3) to the p-tert-butylphenol formaldehyde resin is 35:31.

Comparative Example 9

This example is to illustrate the effect of the weight ratio of the hydrotalcite-sodium phenolate complex to magnesium oxide in the magnesium oxide-hydrotalcite-sodium phenolate complex on the performance of the pre-reaction liquid. Compared with Example 3, the weight ratio of the hydrotalcite-sodium phenolate complex to magnesium oxide in step (3) of the preparation process of this example is 0.3:2.9, which is not within the scope of the claims (0.5-1.5):(2-3.8). The other preparation steps and reagent amounts are the same as those in Example 3.

Application Example 10

This example uses the pre-reaction liquid prepared in Example 3 (the amount added to the chlorinated rubber adhesive is 5, 25, and 50 parts by weight, respectively) and the pre-reaction liquid samples obtained in Comparative Examples 7-9 to prepare the chlorinated rubber adhesive. The weight of the pre-reaction liquid obtained in Comparative Examples 7-9 in the chlorinated rubber adhesive is 50 parts. The formula of the chlorinated rubber adhesive in this example is shown in Table 1:

Table 1 Chlorinated rubber adhesive formula

Preparation method of chlorinated rubber adhesive:

A mixed solvent consisting of toluene, 120# solvent oil and ethyl acetate is added into a rubber preparation kettle at room temperature, chlorinated rubber and antioxidant are added into the mixed solvent and stirred to completely dissolve, and then the pre-reaction liquid is added and stirred thoroughly to obtain the product.

Effect embodiment:

The following is a storage stability test of the pre-reaction solutions obtained in Examples 1-5 and Comparative Examples 6-9. The adhesive strength, heat resistance and storage stability tests were performed on each adhesive sample obtained in Application Example 10. The test methods and test results are shown below.

1. Adhesion test

A 2.5 cm wide canvas was prepared into a sample strip. Each adhesive obtained in Example 10 was evenly coated on a pair of sample pieces. The coating length was about 15 cm, the coating thickness was 0.2 mm, the amount of adhesive was 1000-1200 g/m ² , and it was coated in two layers. After the first layer was naturally air-dried, the second layer was then applied. The coating was air-dried again until the solvent was basically evaporated. When the adhesive layer felt sticky but not sticky to the touch, the adhesive surfaces of the two sample pieces were aligned and bonded, and they were hammered tightly with a hammer. After 24 hours at room temperature, a double-layer canvas bonded sample strip was obtained. The peel strength was tested according to the method of GB-2792-81.

2. Heat resistance test

The double-layer canvas bonded specimens obtained in the above-mentioned adhesion test were placed at 50°C for drying for 120 hours, and the specimens were taken out and their peel strength was tested according to the GB-2792-81 method.

3. Storage stability test

Observe the samples for precipitation and stratification within 5 days.

4. The results in Table 2 show that the pre-reaction liquid samples prepared in Examples 1-5 did not have precipitation and stratification, indicating that Examples 1-5 prepared within the parameter ranges required by the claims all obtained stable pre-reaction liquids that were not prone to solid-liquid stratification. The samples of Comparative Examples 6-9 all produced solid-liquid stratification, indicating that the storage stability of the samples of Comparative Examples 6-9 was poor. The pre-reaction liquid of Comparative Example 6 contained only hydrotalcite and no sodium phenolate, so no phenol anion was adsorbed on the surface of the hydrotalcite inorganic layer plate, and the hydrophilic surface of the hydrotalcite inorganic layer plate was not modified to a hydrophobic surface. The strongly hydrophilic hydrotalcite inorganic layer plate in the hydrophobic organic solvent would cause polymerization and precipitation between the hydrotalcite particles due to the completely opposite properties of the two. Since the pre-reaction liquid sample of Comparative Example 6 immediately showed precipitation and solid-liquid stratification after preparation, its storage performance was very unstable, so the pre-reaction liquid sample of Comparative Example 6 was not used in Application Example 10 to prepare the adhesive and the corresponding test links. The pre-reaction liquid of Comparative Example 7 does not contain the hydrotalcite-sodium phenolate complex. Therefore, in this embodiment, the small molecular weight of the tert-butylphenol formaldehyde resin will first interact with the magnesium oxide, and the molecular chain length of these low molecular weight resins is not enough to form a sufficiently thick adsorption layer on the surface of the magnesium oxide particles, thereby causing the suspended magnesium oxide particles to lose stability and ultimately produce a solid-liquid stratification phenomenon. The preparation process of the pre-reaction solution of Comparative Example 8 does not involve the preparation of the magnesium oxide-hydrotalcite-sodium phenolate composite. The magnesium oxide-hydrotalcite-sodium phenolate composite is formed by the interaction of the electron-donating hydroxyl group located at the edge of the hydrotalcite inorganic layer plate in the hydrotalcite-sodium phenolate composite with the surface of the positively charged active light magnesium oxide particles under heating and a certain reaction time. The magnesium oxide particles in the magnesium oxide-hydrotalcite-sodium phenolate composite are coated by the hydrotalcite-sodium phenolate composite, so that the small molecular weight p-tert-butylphenol formaldehyde resin will first contact the hydrotalcite-sodium phenolate composite wrapped outside the magnesium oxide particles. Since the small molecular weight p-tert-butylphenol formaldehyde resin also contains the same phenol group as that in the hydrotalcite-sodium phenolate composite, according to the principle of like attracts like, these small molecular weight p-tert-butylphenol formaldehyde resins will be adsorbed by the hydrotalcite-sodium phenolate composite layer plate; while in Comparative Example 8, the hydrotalcite-sodium phenolate composite is only physically mixed with magnesium oxide, and no adsorption is produced. The magnesium oxide-hydrotalcite-sodium phenolate complex, that is, the magnesium oxide particles are not coated by the hydrotalcite-sodium phenolate complex, then the small molecular weight p-tert-butylphenol formaldehyde resin with a faster migration rate will directly act on the surface of the magnesium oxide particles, thereby generating a solid-liquid stratification phenomenon. In the preparation process of the pre-reaction liquid of Comparative Example 9, the weight ratio between the hydrotalcite-sodium phenolate complex and the magnesium oxide in step (3) is 0.3:2.9, which is not within the scope of the claims (0.5-1.5): (2-3.8), that is, the amount of the hydrotalcite-sodium phenolate complex is too small, then the surface of the magnesium oxide particles is not completely coated by a sufficient amount of the hydrotalcite-sodium phenolate complex, so that part of the surface of the magnesium oxide particles is exposed, resulting in the small molecular weight p-tert-butylphenol formaldehyde resin being adsorbed on the exposed surface of these magnesium oxide particles. The same as the above reason, the small molecular weight p-tert-butylphenol formaldehyde resin is adsorbed on the surface of the magnesium oxide, which will cause the pre-reaction liquid to generate a solid-liquid stratification phenomenon.

The results in Table 3 show that in Application Example 10, when the weight of Example 3 in the chlorinated rubber adhesive increases from 5 parts to 50 parts, the adhesive's bonding strength, heat resistance and storage stability are constantly increasing, which shows that the pre-reaction solution prepared in Example 3 does play a role in enhancing the performance of the chlorinated rubber adhesive. Although the weight of the samples prepared in Comparative Examples 7-9 in the chlorinated rubber adhesive is also 50 parts, the adhesive performance of these Comparative Examples is far inferior to the adhesive performance of the Example 3 containing the same weight. As for Comparative Example 7, this example does not contain the hydrotalcite-sodium phenolate composite, and the bonding strength and heat resistance of the adhesive of this example are 34.9% and 51.2% lower than the bonding strength and heat resistance of the adhesive of Example 3 (50 parts by weight), respectively, and the adhesive of Comparative Example 7 is unstable and easy to delaminate, which shows that the role of the hydrotalcite-sodium phenolate composite in the present invention is very important. As for Comparative Example 8, this example does not contain magnesium oxide-hydrotalcite-sodium phenolate complex. The bonding strength and heat resistance of the adhesive in this example are 25.6% and 48.8% lower than those of the adhesive in Example 3 (50 parts by weight), respectively. In addition, the adhesive in Comparative Example 8 is unstable and easily delaminated, which shows that the formation of magnesium oxide-hydrotalcite-sodium phenolate complex plays a very important role in the present invention. As for Comparative Example 9, the weight ratio of the hydrotalcite-sodium phenolate complex to magnesium oxide in this example is 0.3:2.9, which is not within the scope of the claims (0.5-1.5):(2-3.8), that is, the amount of the hydrotalcite-sodium phenolate complex is too little. The bonding strength and heat resistance of the adhesive in this example are 18.6% and 29.3% lower than those of the adhesive in Example 3 (50 parts by weight), respectively. In addition, the adhesive in Comparative Example 9 is unstable and easily delaminated, which shows that the ratio of the amount of the hydrotalcite-sodium phenolate complex to magnesium oxide is also very important in the present invention.

Table 2 Results of storage stability tests on the pre-reaction solution samples prepared in Examples 1-5 and the samples prepared in Comparative Examples 6-9

Table 3 Results of the adhesion, heat resistance and storage stability tests of the chlorinated rubber adhesive prepared from samples prepared from Example 3 and Comparative Examples 7-9 (accounting for 50 parts by weight in the adhesive) in Application Example 10

Claims (5)

1. A preparation method of a pre-reaction liquid for an adhesive containing a talcum compound comprises the following preparation steps:

(1) Mixing and stirring aluminum nitrate nonahydrate, magnesium nitrate hexahydrate and distilled water with carbon dioxide removed at room temperature, regulating the pH of the obtained mixed solution to 7.0-10.0 with alkali liquor under the stirring condition of the rotating speed of 100-1000r/min, then reacting for 0.5-3h under the protection of nitrogen and the stirring condition of the rotating speed of 500-1500r/min, placing the obtained mixture into a closed reaction kettle, reacting for 2-24h at 70-120 ℃, filtering the obtained mixture, washing the obtained mixture with distilled water with carbon dioxide removed until the filtrate is neutral, and filtering the obtained jelly for later use;

(2) Mixing the jelly obtained in the step 1, sodium phenolate and distilled water with carbon dioxide removed at room temperature, then reacting for 10-48 hours under the protection of nitrogen and under the stirring condition of the rotating speed of 200-1200r/min, filtering the obtained product, washing the obtained product with distilled water with carbon dioxide removed until the filtrate is neutral, drying the filtered precipitate at 80-115 ℃ for 10-48 hours, and grinding the dried solid into (300-500) mesh white hydrotalcite-sodium phenolate composite powder for later use;

(3) A solution of the hydrotalcite-containing compound was prepared by the following preparation method: adding hydrotalcite-sodium phenolate compound powder prepared in the step (2) and magnesium oxide into a mixed solvent of ethyl acetate and cyclohexane, carrying out reflux reaction on the obtained mixture for 3-6 hours at 45-70 ℃ under the stirring condition of the rotating speed of 200-3000r/min, and then standing for 12-36 hours to obtain a solution containing the magnesium oxide-hydrotalcite-sodium phenolate compound, wherein the weight ratio of the hydrotalcite-sodium phenolate compound powder prepared in the step (2) to the magnesium oxide, the ethyl acetate and the cyclohexane is (0.75-1.5): (2.4-3.8): (1.4-2): (25-38);

(4) Adding p-tert-butylphenol formaldehyde resin into the solution containing the magnesium oxide-hydrotalcite-sodium phenolate compound prepared in the step (3), and carrying out reflux reaction on the obtained mixture for 6-10h at 25-60 ℃ under the stirring condition of the rotating speed of 200-1200r/min to obtain a pre-reaction solution for the chlorinated rubber adhesive.

2. The process according to claim 1, wherein the lye in step (1) is a 5-25wt% NaOH solution.

3. The production method according to claim 1, wherein the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and carbon dioxide-removing water in step (1) is (1-1.06): (0.32-0.43): (15-30).

4. The preparation method of claim 1, wherein the weight ratio of the jelly obtained in the step (2) to the sodium phenolate to the distilled water from which the carbon dioxide is removed is 1: (0.22-0.46): (5-14).

5. The preparation method according to claim 1, wherein the solution containing magnesium oxide-hydrotalcite-sodium phenolate complex prepared in step (3) and p-tert-butylphenol formaldehyde resin are both prepared in step (4) in a weight ratio of (24-46): (22-40).

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