High-temperature-resistant adhesive as well as preparation method and application thereof

Abstract

The invention provides a high-temperature-resistant adhesive as well as a preparation method and application thereof, and relates to the technical field of adhesives. The high-temperature-resistant adhesive provided by the invention is prepared from the following raw materials in parts by mass: 4 parts of starch, 1 part of acrylic resin, 1 part of shellac, 1 part of rosin, 1 part of asphalt, 1 part of polyvinyl alcohol, 1 part of carboxymethylcellulose, 6 parts of carbon fiber powder and 22 parts of water. The high-temperature-resistant adhesive provided by the invention has the characteristics of strong cohesiveness and excellent high-temperature resistance, is used for repairing the carbon-carbon thermal insulation cylinder, can generate a high-temperature-resistant, stable and complete protective coating, effectively solves the problems of outer wall blanks, pits and the like of the existing carbon / carbon thermal insulation cylinder, has a good protective effect on the carbon-carbon thermal insulation cylinder, and is safe and reliable. The repaired carbon-carbon thermal insulation cylinder is long in service life and attractive in appearance. In addition, the high-temperature-resistant adhesive provided by the invention is low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a high temperature resistant adhesive and a preparation method and application thereof. Background Art

[0002] Carbon-carbon composite materials have the advantages of low density, high specific gravity, ablation resistance, small thermal expansion coefficient, excellent thermal shock resistance, good friction and wear performance, etc. They are widely used in high-tech fields such as aviation, aerospace, machinery, chemical industry, electronics, metallurgy, medicine and defense industry. The preparation process of carbon-carbon composite materials includes the densification and molding process of carbon fiber preforms. The densification methods include chemical vapor deposition and liquid phase impregnation. The carbon-carbon insulation tube will deform during the preparation process. Some parts of the inner wall of the tube cannot be machined during processing, resulting in blanks. Adhesives are needed to repair the inner wall of the blank area.

[0003] Existing adhesives are often prepared from raw materials such as polypropylene and cohesive substances such as urethane, which are difficult to form a protective coating and have a poor protective effect on carbon-carbon insulation tubes. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a high temperature resistant adhesive and its preparation method and application. The high temperature resistant adhesive provided by the present invention has strong bonding and excellent high temperature resistance, and can form a complete protective layer when used for repairing carbon-carbon insulation tubes, and has excellent protective effect on carbon-carbon insulation tubes.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a high temperature resistant adhesive, which comprises the following preparation raw materials, measured by weight: 4 parts of starch, 1 part of acrylic resin, 1 part of shellac, 1 part of rosin, 1 part of asphalt, 1 part of polyvinyl alcohol, 1 part of carboxymethyl cellulose, 6 parts of carbon fiber powder, and 22 parts of water.

[0007] Preferably, the particle size of the carbon fiber powder is 5 to 50 μm.

[0008] The present invention provides a method for preparing the high temperature resistant adhesive described in the above technical solution, comprising the following steps:

[0009] Mixing starch, shellac, rosin, asphalt, polyvinyl alcohol and water to carry out esterification reaction to obtain an esterification reaction product;

[0010] The esterification reaction product is subjected to a polycondensation reaction to obtain a semi-finished adhesive product;

[0011] The semi-finished adhesive product, carboxymethyl cellulose and carbon fiber powder are mixed to carry out addition polymerization, and then acrylic resin is added to dilute to obtain a high temperature resistant adhesive.

[0012] Preferably, the esterification reaction temperature is 90-210° C. and the reaction time is 1-3 hours.

[0013] Preferably, the heating rate from room temperature to the temperature of the esterification reaction is 3-5°C / min.

[0014] Preferably, the polycondensation reaction is carried out at a temperature of 20 to 80° C. and for a time of 0.5 to 3 hours.

[0015] Preferably, the temperature of the addition polymerization reaction is 200-215° C., and the time is 2-4 hours.

[0016] Preferably, it is characterized in that the temperature is raised to the temperature of the addition polymerization reaction at a rate of 3 to 5°C / min.

[0017] Preferably, the polyaddition reaction system obtained by the polyaddition reaction is first cooled to 50-60° C. and then the acrylic resin is added for dilution.

[0018] The present invention also provides the use of the high temperature resistant adhesive described in the above technical solution or the high temperature resistant adhesive prepared by the preparation method described in the above technical solution in the repair of carbon-carbon insulation tubes.

[0019] The present invention provides a high temperature resistant adhesive, which comprises the following raw materials by weight: 4 parts of starch, 1 part of acrylic resin, 1 part of shellac, 1 part of rosin, 1 part of asphalt, 1 part of polyvinyl alcohol, 1 part of carboxymethyl cellulose, 6 parts of carbon fiber powder, and 22 parts of water. Among them, starch is a base material, and the main component plays an adhesive role. Acrylic resin is a curing agent, which can cross-link low molecular compounds or linear polymer compounds into a network structure, forming an insoluble and infusible solid adhesive layer. At the same time, acrylic resin also plays a certain role of a diluent, and the viscosity of the high temperature resistant adhesive can be adjusted. Shellac is an insect repellent to prevent insect erosion. Rosin plays a bonding role in the adhesive. Since the rosin itself has good adhesion, it can bond other components in the adhesive together to form a strong and reliable bond. Asphalt has good chemical stability, which can prevent the adhesive from being corroded by chemical substances, thereby extending the service life of the adhesive. Polyvinyl alcohol can achieve a bonding effect, and has relatively strong transparency and water resistance. Carboxymethyl cellulose is a thickener, which makes the adhesive more viscous and easy to form a protective coating. Carbon fiber powder can increase the viscosity of the adhesive and can also improve the high temperature resistance of the adhesive. The high temperature resistant adhesive provided by the present invention has strong bonding and excellent high temperature resistance. When used in the repair of carbon-carbon insulation tubes, it can form a stable, high temperature resistant protective coating. The coating will not crack and has a good protective effect on the carbon-carbon insulation tube. It can significantly increase the service life of the carbon-carbon insulation tube, and effectively solves the problems of the existing carbon / carbon insulation tube outer wall blanks, pits, etc. The repaired carbon-carbon insulation tube product has a beautiful appearance. Moreover, the high temperature resistant adhesive provided by the present invention is low in cost. DETAILED DESCRIPTION

[0020] The present invention provides a high temperature resistant adhesive, which comprises the following raw materials by weight: 4 parts of starch, 1 part of acrylic resin, 1 part of shellac, 1 part of rosin, 1 part of asphalt, 1 part of polyvinyl alcohol, 1 part of carboxymethyl cellulose, 6 parts of carbon fiber powder, and 22 parts of water. In the present invention, the particle size of the carbon fiber powder is preferably 20 μm. In the present invention, the acrylic resin preferably comprises DIANAL.

[0021] When the high temperature resistant adhesive provided by the present invention is used for repairing carbon-carbon heat preservation tubes, the rosin and shellac components will rise to the surface to form a protective coating.

[0022] The present invention provides a method for preparing the high temperature resistant adhesive described in the above technical solution, characterized in that it comprises the following steps:

[0023] Mixing starch, shellac, rosin, asphalt, polyvinyl alcohol and water to carry out esterification reaction to obtain an esterification reaction product;

[0024] The esterification reaction product is subjected to a polycondensation reaction to obtain a semi-finished adhesive product;

[0025] The semi-finished adhesive product, carboxymethyl cellulose and carbon fiber powder are mixed to carry out addition polymerization, and then acrylic resin is added to dilute to obtain a high temperature resistant adhesive.

[0026] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0027] The invention mixes starch, shellac, rosin, asphalt, polyvinyl alcohol and water, and performs esterification reaction to obtain an esterification reaction product.

[0028] In the present invention, the mixing preferably comprises: mixing starch, shellac, rosin and asphalt, and then adding polyvinyl alcohol and water to mix. In the present invention, the mixing temperature is preferably room temperature, the mixing is preferably stirred and mixed; the polyvinyl alcohol and water are preferably added by pumping.

[0029] In the present invention, the temperature of the esterification reaction is preferably 90-210°C, more preferably 140-200°C, and further preferably 150-180°C; the heating rate from room temperature to the temperature of the esterification reaction is preferably 3-5°C / min, and more preferably 4°C / min; starting from the time when the temperature rises to the temperature of the esterification reaction, the time of the esterification reaction is preferably 1-3h, more preferably 1.5-2.5h, and further preferably 1.5-2h.

[0030] After obtaining the esterification reaction product, the present invention performs a polycondensation reaction on the esterification reaction product to obtain a semi-finished adhesive product.

[0031] In the present invention, the temperature of the polycondensation reaction is preferably 20 to 80°C, more preferably 50 to 80°C, and further preferably 70 to 80°C; the time of the polycondensation reaction is preferably 0.5 to 3h, more preferably 0.75 to 2.5h, and further preferably 1 to 2h.

[0032] After the polycondensation reaction is completed, the present invention preferably further comprises cooling the system obtained by the condensation reaction to below 30° C. to obtain a semi-finished adhesive. The present invention has no particular limitation on the cooling, and any cooling method known to those skilled in the art can be used.

[0033] After obtaining the semi-finished adhesive, the present invention mixes the semi-finished adhesive, carboxymethyl cellulose and carbon fiber powder, performs addition polymerization, and then adds acrylic resin for dilution to obtain a high temperature resistant adhesive.

[0034] In the present invention, the temperature of the addition polymerization reaction is preferably 200-215°C, more preferably 205-215°C, and further preferably 208-215°C; the heating rate from below 30°C to the temperature of the addition polymerization reaction is preferably 3-4°C / min, and more preferably 4°C / min; starting from the time when the temperature rises to the temperature of the addition polymerization reaction, the time of the addition polymerization reaction is preferably 2.5-3h, and more preferably 3h; in a specific embodiment of the present invention, the reaction is preferably stopped when the viscosity at 80°C is 10-80cP (more preferably 10-50cP, and further preferably 14-22cP).

[0035] In the present invention, the polyaddition reaction system obtained by the polyaddition reaction is preferably first cooled (referred to as the first cooling) to 50-60°C (more preferably 55-60°C), and then acrylic resin is added for dilution, and then cooled (second cooling) to below 30°C under stirring conditions. The present invention has no special limitation on the first cooling, and a cooling method well known to those skilled in the art can be used. In the present invention, during the second cooling process, the volatilized acrylic resin flows back into the material through the condenser to achieve cooling of the material.

[0036] The present invention also provides the use of the high temperature resistant adhesive described in the above technical solution or the high temperature resistant adhesive prepared by the preparation method described in the above technical solution in the repair of carbon-carbon insulation tubes. In the present invention, the carbon-carbon insulation tube repair preferably includes the repair of the straight arm blank of the carbon-carbon insulation tube or the repair of the pits of the carbon-carbon insulation tube. The key raw materials of the high temperature resistant adhesive prepared by the present invention are carbon fiber powder, water and acrylic resin. The above three raw materials are the decisive factors. In addition to its high temperature resistance and improving the viscosity of the adhesive, the carbon fiber powder also plays a color adjustment role because its color is consistent with that of the carbon-carbon composite material with a small deviation. In addition, after it is mixed with the other raw materials and becomes a finished product of the high temperature resistant adhesive, during use, after the carbon-carbon insulation tube blank is repeatedly coated and polished, the carbon-carbon insulation tube blank can finally be perfectly repaired, and after the subsequent product is coated, there is no cracking in the repaired area and the product is uneven, which can perfectly solve the problem of the outer wall of the carbon-carbon insulation tube.

[0037] In order to further illustrate the present invention, the high temperature resistant adhesive and its preparation method and application are described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] In the following examples, the acrylic resin is an ultra-fine acrylic resin powder water-soluble SH-B63 water-based coating resin powder product.

[0039] Example 1

[0040] At room temperature, starch, shellac, rosin and asphalt are put into a reactor, and then polyvinyl alcohol and water are pumped in, and the temperature is raised to 180°C at a rate of 3°C / min, and then the esterification reaction is kept warm for 2 hours; when the system temperature reaches 80°C, the polycondensation reaction is carried out for 1.5 hours, and after the reaction is completed, the material is cooled to 30°C and discharged to obtain an adhesive semi-finished product; the adhesive semi-finished product is put into a polymerization reactor, carboxymethyl cellulose and carbon fiber powder (20μm) are added, and the temperature is raised to 208°C at a rate of 4°C / min. When the viscosity reaches the standard (viscosity is 18-22cP at 80°C), the reaction is stopped, cooled to 60°C, and acrylic resin (DIANAL) is added for dilution. The volatilized acrylic resin is refluxed through a condenser until the material is cooled to below 30°C to obtain a high temperature resistant adhesive (carbon-carbon insulation cylinder outer straight arm blank repair adhesive), which is packaged as a finished product. Among them, the mass ratio of starch, acrylic resin, shellac, rosin, asphalt, polyvinyl alcohol, carboxymethyl cellulose, carbon fiber powder and water is 4:1:1:1:1:1:1:6:22.

[0041] For carbon-carbon insulation tubes, whether they are repaired or unrepaired, if the allowable deviation is not specified in the dimensions, it shall be implemented in accordance with the provisions of the national standard size GB / T 1804 rough grade C. The remaining density and other aspects meet the national standard requirements for carbon-carbon insulation tubes (YS / T977-2014).

[0042] Example 2

[0043] At room temperature, starch, shellac, rosin and asphalt are put into a reactor, and then polyvinyl alcohol and water are pumped in, and the temperature is raised to 90°C at a rate of 3°C / min, and then the esterification reaction is kept warm for 2 hours; when the system temperature reaches 60°C, the polycondensation reaction is carried out for 1.5 hours, and after the reaction is completed, the material is cooled to 30°C and discharged to obtain an adhesive semi-finished product; the adhesive semi-finished product is put into a polymerization reactor, carboxymethyl cellulose and carbon fiber powder (20μm) are added, and the temperature is raised to 100°C at a rate of 4°C / min. When the viscosity reaches the standard (viscosity is 14-18cP at 80°C), the reaction is stopped, cooled to 60°C, and acrylic resin (DIANAL) is added for dilution. The volatilized acrylic resin is refluxed through a condenser until the material is cooled to below 30°C to obtain a high temperature resistant adhesive (carbon-carbon insulation cylinder outer straight arm blank repair adhesive), which is then packaged as a finished product. Among them, the mass ratio of starch, acrylic resin, shellac, rosin, asphalt, polyvinyl alcohol, carboxymethyl cellulose, carbon fiber powder and water is 4:1:1:1:1:1:1:6:22.

[0044] For carbon-carbon insulation tubes, whether they are repaired or unrepaired, if the allowable deviation is not specified in the dimensions, it shall be implemented in accordance with the provisions of the national standard size GB / T 1804 rough grade C. The remaining density and other aspects meet the national standard requirements for carbon-carbon insulation tubes (YS / T977-2014).

[0045] Example 3

[0046] At room temperature, starch, shellac, rosin and asphalt are put into a reactor, and then polyvinyl alcohol and water are pumped in, and the temperature is raised to 180°C at a rate of 3°C / min, and then the esterification reaction is kept warm for 1 hour; when the system temperature reaches 80°C, the polycondensation reaction is carried out for 0.75h, and after the reaction is completed, the material is cooled to 30°C and discharged to obtain an adhesive semi-finished product; the adhesive semi-finished product is put into a polymerization reactor, carboxymethyl cellulose and carbon fiber powder (20μm) are added, and the temperature is raised to 208°C at a rate of 4°C / min. When the viscosity reaches the standard (viscosity is 18-22cP at 80°C), the reaction is stopped, cooled to 60°C, and acrylic resin (DIANAL) is added for dilution. The volatilized acrylic resin is refluxed through a condenser until the material is cooled to below 30°C to obtain a high temperature resistant adhesive (carbon-carbon insulation cylinder outer straight arm blank repair adhesive), which is packaged as a finished product. Among them, the mass ratio of starch, acrylic resin, shellac, rosin, asphalt, polyvinyl alcohol, carboxymethyl cellulose, carbon fiber powder and water is 4:1:1:1:1:1:1:6:22.

[0047] For carbon-carbon insulation tubes, whether they are repaired or unrepaired, if the allowable deviation is not specified in the dimensions, it shall be implemented in accordance with the provisions of the national standard size GB / T 1804 rough grade C. The remaining density and other aspects meet the national standard requirements for carbon-carbon insulation tubes (YS / T977-2014).

[0048] After the outer wall blank area of ​​the carbon-carbon insulation tube was repaired with the high-temperature resistant adhesive prepared in this embodiment, the performance test results before and after the repair are shown in Table 1. After verification by vapor phase coating, after 1020°C vapor phase coating, the outer wall showed bright silver color, and the coating was perfectly formed with high hardness, wear resistance and oxidation resistance. The oxidation resistance test was carried out at 1500°C and in air for 10 hours to measure the weight gain rate. There is no abnormality in the appearance of the outer wall of the blank at the repaired part (less than 1.5mm, and the repair thickness shall not exceed 2mm) and the rest of the normal area. After the test was carried out in a high-temperature furnace, the carbon atoms were rearranged at a high temperature of 1900°C to optimize the structural performance. No cracks were found at the repaired blank after it was taken out of the furnace. The temperature of the single crystal furnace is generally around 1600°C. Therefore, the high-temperature resistant adhesive provided by the present invention can fully meet the requirements of the carbon-carbon insulation tube repair process.

[0049] Table 1 Performance comparison before and after repair

[0050] project Before repair Example 1 Example 2 Example 3 Mechanical strength 80MPa 140MPa 110MPa 120MPa Purity (solar grade) 80ppm 80ppm 80ppm 80ppm density <![CDATA[>1.2g / cm 3 ]]> <![CDATA[>1.2g / cm 3 ]]> <![CDATA[>1.2g / cm 3 ]]> <![CDATA[>1.2g / cm 3 <!-- 4 -->]]> Rockwell hardness 38HRC 43HRC 40HRC 42HRC Quality wear 0.5g 0.3g 0.4g 0.35g Oxidation weight gain rate 1.8％ 2.1％ 2.0％ 2.1％

[0051] It can be seen that the high temperature resistant adhesive provided by the present invention has the characteristics of strong adhesion and excellent high temperature resistance. It is used to repair the carbon-carbon insulation tube and can produce a high temperature resistant, stable and complete protective coating, which effectively solves the problems of the existing carbon / carbon insulation tube outer wall blanks, pits and other problems. It has a good protective effect on the carbon-carbon insulation tube, and the repaired carbon-carbon insulation tube has a long service life and is beautiful.

[0052] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A high temperature resistant adhesive, characterized in that: The preparation material comprises the following raw materials, in parts by mass: 4 parts of starch, 1 part of acrylic resin, 1 part of shellac, 1 part of rosin, 1 part of asphalt, 1 part of polyvinyl alcohol, 1 part of carboxymethyl cellulose, 6 parts of carbon fiber powder and 22 parts of water.

2. The high temperature resistant adhesive according to claim 1, characterized in that: The particle size of the carbon fiber powder is 5 to 50 μm.

3. The method for preparing the high temperature resistant adhesive according to claim 1 or 2, characterized in that: The following steps are involved: Mixing starch, shellac, rosin, asphalt, polyvinyl alcohol and water to carry out esterification reaction to obtain an esterification reaction product; The esterification reaction product is subjected to a polycondensation reaction to obtain a semi-finished adhesive product; The semi-finished adhesive product, carboxymethyl cellulose and carbon fiber powder are mixed to carry out addition polymerization, and then acrylic resin is added to dilute to obtain a high temperature resistant adhesive.

4. The preparation method according to claim 3, characterized in that: The temperature of the esterification reaction is 90-210° C. and the time is 1-3 hours.

5. The preparation method according to claim 2 or 4, characterized in that: The temperature is raised from room temperature to the temperature of the esterification reaction at a rate of 3 to 5°C / min.

6. The preparation method according to claim 3, characterized in that: The temperature of the polycondensation reaction is 20-80° C., and the time is 0.5-3 hours.

7. The preparation method according to claim 3, characterized in that: The temperature of the addition polymerization reaction is 200-215° C., and the time is 2-4 hours.

8. The preparation method according to claim 3 or 7, characterized in that: The temperature is raised to the temperature of the addition polymerization reaction at a rate of 3 to 5°C / min.

9. The preparation method according to claim 3 or 7, characterized in that: The polyaddition reaction system obtained by the polyaddition reaction is first cooled to 50-60° C. and then acrylic resin is added for dilution.

10. Use of the high temperature resistant adhesive according to any one of claims 1 to 2 or the high temperature resistant adhesive prepared by the preparation method according to any one of claims 3 to 9 in the repair of carbon-carbon insulation tubes.