1. The utility model provides a carbon fiber reinforced die mould graphite pipe which characterized in that: the graphite tube is prepared from the following raw materials in parts by weight: 20-30 parts of phenolic resin, 2-6 parts of epoxy resin, 1-3 parts of zinc chloride, 6-12 parts of nitrile rubber, 6-12 parts of carbon fiber, 6-12 parts of siloxane, 200-400 parts of ethanol and 65-85 parts of graphite powder.

2. The carbon fiber reinforced profiled graphite tube of claim 1, wherein: the graphite powder is prepared from high-purity graphite, the graphite content is more than or equal to 99.9 percent, and the preparation method of the graphite powder comprises the following steps: the proportion of 30-60 meshes of graphite powder is 2/3, and the proportion of 80-100 meshes of graphite powder is 1/3.

3. The carbon fiber reinforced profiled graphite tube of claim 1, wherein: the carbon fiber is a commercial product of high-modulus carbon fiber, the length of the fiber is 5-50mm, and the purity of the fiber is more than or equal to 99.9%.

4. The carbon fiber reinforced profiled graphite tube of claim 1, wherein: the phenolic resin is prepared from the following raw materials in parts by mass: formaldehyde: sodium carbonate 100: 45: 1; the specific manufacturing process method comprises the following steps:

(1) dissolving phenol into liquid from the crystal, and then putting the phenol into a reaction kettle;

(2) putting formaldehyde into a reaction kettle, keeping the temperature in the reaction kettle at 35-40 ℃, stirring for 10-15 minutes, opening an atmospheric valve before stirring, and stopping stirring for 2-3 minutes after stirring uniformly;

(3) adding a sodium carbonate catalyst into the kettle, closing all valves, starting stirring and heating, wherein the stirring and heating speed is less than or equal to 1.5 ℃/min, stopping heating and stirring when the stirring and heating is carried out until the temperature in the kettle is 85 ℃, opening an atmospheric valve and a reflux valve, and waiting for reflux;

(4) timing when the reflux valve begins to generate reflux, naturally refluxing the reflux in 20 minutes before refluxing, stirring after 20 minutes, and controlling the heating device to reflux under the constant temperature condition;

(5) when the stirring reflux is close to the end point, sampling is carried out once every 10 minutes, the reflux time is controlled according to the water stratification, and when the resin-water stratification ratio is 2: 1, reaching the polymerization end point, and ending the reflux time;

(6) when the polymerization end point is reached, continuously stirring, opening cooling water to cool, adding hydrochloric acid to neutralize until the pH value is 7 when the temperature of the kettle reaches 60 ℃;

(7) adding water for washing, wherein the adding amount of the water is 1.5 times of the volume of the resin, and washing off salt in the resin;

(8) standing for layering, removing a water layer, closing a reflux valve, opening a dehydration valve, and preparing for dehydration treatment;

(9) carrying out vacuum dehydration with the vacuum degree of 0.085-0.095 MPa, maintaining for 30-40 minutes, sampling and observing, and dehydrating for 150-210 minutes;

(10) sampling every 10 minutes, cooling to 20 ℃ to observe whether the resin is transparent or not, and when the detection indexes are as follows: the dehydration end point is set when the water content is less than or equal to 8 percent and the viscosity is 90 'to 300';

(11) closing the dewatering valve, stopping the vacuum pump, continuing stirring, opening cooling water to cool to 30-35 ℃, taking the resin out of the kettle, filtering, and storing in a resin storage tank for later use.

5. The carbon fiber reinforced profiled graphite tube of claim 4, wherein: in the step (6), the mass fraction of the hydrochloric acid is 36%.

6. The carbon fiber reinforced profiled graphite tube of claim 1, wherein: the epoxy resin is prepared from the following raw materials in percentage by mass: bisphenol A: sodium hydroxide: benzene: 100 parts of deionized water: 126: 33: 438: 219;

the specific manufacturing process method comprises the following steps:

(1) completely pumping epoxy chloropropane into a reaction kettle, and pumping bisphenol A into the reaction kettle to distribute the bisphenol A on the epoxy chloropropane;

(2) introducing steam to enable the temperature in the reaction kettle to reach 70 ℃, starting a stirrer after bisphenol A is completely melted, continuously stirring and heating to 75 ℃, and turning off the steam;

(3) dropwise adding a sodium hydroxide aqueous solution with the mass fraction of 20% into a reaction kettle;

(4) the dropping speed is controlled by observing the temperature change, and the temperature of the reaction kettle is ensured to be less than or equal to 75 ℃ in the dropping process;

(5) continuously stirring for 1.5 hours after the dropwise adding is finished, keeping the temperature of the reaction kettle at 74-75 ℃ by keeping introducing steam, turning off the heating steam until the temperature in the kettle is reduced to 60 ℃, and carrying out primary water washing;

(6) adding 57% of benzene into the high-level tank;

(7) starting a condensation system, adding benzene liquid in the high-level tank into the reaction kettle, and adding deionized water accounting for 60% of the total amount into the high-level tank;

(8) continuing stirring for 30 minutes, then standing for layering for 50 minutes, opening a kettle bottom valve, discharging a water layer, performing secondary water washing, adding the residual benzene and deionized water into the high-level tank, and repeating the step (8);

(9) and (3) distillation: opening a vacuum system at normal temperature, evaporating benzene liquid, and observing the flow rate of reflux liquid: enabling the reflux to stably and slowly flow down along the visual clock wall, slowly raising the temperature of the reaction kettle when the reflux of the condensate is less, continuously controlling the reflux amount, and stopping heating when the kettle temperature is 70 ℃ until the reflux is basically stopped;

(10) discharging, and recovering benzene liquid for treatment.

7. The carbon fiber reinforced profiled graphite tube of claim 6, wherein: in the step (4), the temperature of the reaction kettle is 73-74 ℃ in the dripping process, the flow rate is slow in the dripping process, the flow rate can be increased after one hour, and the total dripping time is 345-375 minutes.

8. A method of producing a carbon fibre reinforced profiled graphite tube as claimed in any one of claims 1 to 7, characterised in that: the method comprises the following steps:

(1) resin components: putting phenolic resin and epoxy resin into a container, heating to 50 ℃, continuously stirring for 30 minutes, and then keeping for later use;

(2) carbon fiber treatment: soaking the carbon fiber by siloxane and ethanol for 3-6 hours, and then air-drying for later use;

(3) adding zinc chloride, nitrile rubber, graphite powder and air-dried carbon fibers into a mixer, uniformly mixing and stirring, then discharging, screening and separating, manually breaking the large particles into lumps, and mixing in the mixer;

(4) putting the materials in the step (1) and the step (3) into a kneading pot for kneading for 50-70 minutes;

(5) and (4) sealing and storing the kneaded material for 24 hours, and then putting the kneaded material into an extruder to extrude and form a graphite tube.

9. The method of making a carbon fiber reinforced profiled graphite tube of claim 8, wherein: before the materials in the step (4) are put into a kneading pot, the viscosity of the resin component prepared in the step (1) is kept at 1-4 minutes, before the materials are put, the resin component is heated to 50-55 ℃ by water bath, and then the resin component is put into the kneading pot at one time; the kneading pot is controlled at 45 ℃ in summer and 75 ℃ in winter.

10. The method of making a carbon fiber reinforced profiled graphite tube of claim 8, wherein: in the step (5), the extrusion pressure of the extruder is 18Mpa, the bin temperature of the extruder is 50-60 ℃, the head temperature is 75-85 ℃, and the outlet temperature of the nozzle is 190-200 ℃.

Background

With the rapid development of the current world industry, the graphite tubular heat exchanger is widely applied to the industrial fields of petrochemical industry, medicine, light industry, metallurgy, textile and the like due to the excellent corrosion resistance, high thermal conductivity and lower price, and a large amount of precious metal materials are saved for the country. However, since it is difficult to make a breakthrough in temperature, pressure, thermal expansion coefficient, service life, etc., the application range of graphite equipment is greatly limited.

The traditional graphite tubular heat exchanger has a plurality of problems in production practice and application, such as: small pressure resistance, poor temperature resistance, short service life, high repair rate, poor quality stability and the like. The most problematic link is the fracture or leakage of graphite heat exchange.

Traditional die mould graphite pipe is by high viscosity phenolic resin and graphite powder through hot extrusion moulding, and the material composition is: the mass percent of the phenolic resin is about 23 percent, the mass percent of the graphite powder is about 77 percent, and the physical and mechanical properties of the traditional phenolic resin profiled graphite pipe are as follows: the volume density is more than or equal to 1800kg/m³(ii) a The compressive strength is more than or equal to 73.5 MPa; the tensile strength is more than or equal to 16.7 MPa; the bending strength is more than or equal to 50.0 (phi 32/phi 22) MPa; a thermal conductivity of 31.4-40.7W/(m & lt K.); coefficient of linear expansion 8.2 x 10-⁶/℃。

The pressed graphite heat exchange tube produced by the traditional process method has the defects of low mechanical strength, poor toughness, poor thermal shock resistance and easy fracture in use. Therefore, the key for improving the overall performance of the graphite tubular heat exchanger is to solve the technical problems of good strength, toughness and dimensional stability of the graphite heat exchange tube.

Disclosure of Invention

The invention aims to provide a carbon fiber reinforced compression type graphite tube and a preparation method thereof. The graphite tube and the method solve the defects that the traditional graphite heat exchange tube is made of brittle materials, and improve the overall performance of the graphite tube-in-tube heat exchanger by improving the strength, toughness and dimensional stability of the graphite heat exchange tube.

The technical scheme of the invention is as follows: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 20-30 parts of phenolic resin, 2-6 parts of epoxy resin, 1-3 parts of zinc chloride, 6-12 parts of nitrile rubber, 6-12 parts of carbon fiber, 6-12 parts of siloxane, 200-400 parts of ethanol and 65-85 parts of graphite powder.

In the carbon fiber reinforced pressed graphite tube, the graphite powder is prepared from high-purity graphite, the graphite content is not less than 99.9%, and the graphite powder preparation method comprises the following steps: the proportion of 30-60 meshes of graphite powder is 2/3, and the proportion of 80-100 meshes of graphite powder is 1/3.

In the carbon fiber reinforced compression type graphite tube, the carbon fibers are high-modulus carbon fiber commercial products, the length of the fibers is 5-50mm, and the purity of the fibers is more than or equal to 99.9%.

In the carbon fiber reinforced pressed graphite tube, the phenolic resin is prepared from the following raw materials in parts by mass: formaldehyde: sodium carbonate 100: 45: 1; the specific manufacturing process method comprises the following steps:

(1) dissolving phenol into liquid from the crystal, and then putting the phenol into a reaction kettle;

(2) putting formaldehyde into a reaction kettle, keeping the temperature in the reaction kettle at 35-40 ℃, stirring for 10-15 minutes, opening an atmospheric valve before stirring, and stopping stirring for 2-3 minutes after stirring uniformly;

(3) adding a sodium carbonate catalyst into the kettle, closing all valves, starting stirring and heating, wherein the stirring and heating speed is less than or equal to 1.5 ℃, stirring and heating to 85 ℃, stopping heating and stirring under the condition of 85 ℃ in the kettle, opening an atmospheric valve and a reflux valve, and waiting for reflux;

(4) timing when the reflux valve begins to generate reflux, naturally refluxing the reflux in 20 minutes before refluxing, stirring after 20 minutes, and controlling the heating device to reflux under the constant temperature condition;

(5) when the stirring reflux is close to the end point, sampling is carried out once every 10 minutes, the reflux time is controlled according to the water stratification, and when the resin-water stratification ratio is 2: 1, reaching the polymerization end point, and ending the reflux time;

(6) when the polymerization end point is reached, continuously stirring, opening cooling water to cool, adding hydrochloric acid to neutralize until the pH value is 7 when the temperature of the kettle reaches 60 ℃;

(7) adding water for washing, wherein the adding amount of the water is 1.5 times of the volume of the resin, and washing off salt in the resin;

(8) standing for layering, removing a water layer, closing a reflux valve, opening a dehydration valve, and preparing for dehydration treatment;

(9) carrying out vacuum dehydration with the vacuum degree of 0.085-0.095 MPa, maintaining for 30-40 minutes, sampling and observing, and dehydrating for 150-210 minutes;

(10) sampling every 10 minutes, cooling to 20 ℃ to observe whether the resin is transparent or not, and when the detection indexes are as follows: the dehydration end point is set when the water content is less than or equal to 8 percent and the viscosity is 90 'to 300';

(11) closing the dewatering valve, stopping the vacuum pump, continuing stirring, opening cooling water to cool to 30-35 ℃, taking the resin out of the kettle, filtering, and storing in a resin storage tank for later use.

In the carbon fiber reinforced pressed graphite tube, in the step (6), the mass fraction of hydrochloric acid is 36%.

In the carbon fiber reinforced pressed graphite tube, the epoxy resin is prepared from the following raw materials in parts by mass: bisphenol A: sodium hydroxide: benzene: 100 parts of deionized water: 126: 33: 438: 219;

the specific manufacturing process method comprises the following steps:

(1) completely pumping epoxy chloropropane into a reaction kettle, and pumping bisphenol A into the reaction kettle to distribute the bisphenol A on the epoxy chloropropane;

(2) introducing steam to enable the temperature in the reaction kettle to reach 70 ℃, starting a stirrer after bisphenol A is completely melted, continuously stirring and heating to 75 ℃, and turning off the steam;

(3) dropwise adding a sodium hydroxide aqueous solution with the mass fraction of 20% into a reaction kettle;

(4) the dropping speed is controlled by observing the temperature change, and the temperature of the reaction kettle is ensured to be less than or equal to 75 ℃ in the dropping process;

(5) continuously stirring for 1.5 hours after the dropwise adding is finished, keeping the temperature of the reaction kettle at 74-75 ℃ by keeping introducing steam, turning off the heating steam until the temperature in the kettle is reduced to 60 ℃, and carrying out primary water washing;

(6) adding 57% of benzene into the high-level tank;

(7) starting a condensation system, adding benzene liquid in the high-level tank into the reaction kettle, and adding deionized water accounting for 60% of the total amount into the high-level tank;

(8) continuing stirring for 30 minutes, then standing for layering for 50 minutes, opening a kettle bottom valve, discharging a water layer, performing secondary water washing, adding the residual benzene and deionized water into the high-level tank, and repeating the step (8);

(9) and (3) distillation: opening a vacuum system at normal temperature, evaporating benzene liquid, and observing the flow rate of reflux liquid: enabling the reflux to stably and slowly flow down along the visual clock wall, slowly raising the temperature of the reaction kettle when the reflux of the condensate is less, continuously controlling the reflux amount, and stopping heating when the kettle temperature is 70 ℃ until the reflux is basically stopped;

(10) discharging, and recovering benzene liquid for treatment.

In the carbon fiber reinforced pressure type graphite tube, in the step (4), the temperature of the reaction kettle is 73-74 ℃ in the dropping process, the flow rate is slow at the beginning of the dropping process, the flow rate can be increased after one hour, and the total dropping time is 345-375 minutes.

The preparation method of the carbon fiber reinforced compression type graphite tube comprises the following steps:

(1) resin components: putting phenolic resin and epoxy resin into a container, heating to 50 ℃, and continuously stirring for 30 minutes;

(2) carbon fiber treatment: soaking the carbon fiber by siloxane and ethanol for 3-6 hours, and then air-drying for later use;

(3) adding zinc chloride, nitrile rubber, graphite powder and air-dried carbon fibers into a mixer, uniformly mixing and stirring, then discharging, screening and separating, manually breaking the large particles into lumps, and mixing in the mixer;

(4) putting the materials in the step (1) and the step (3) into a kneading pot for kneading for 50-70 minutes;

(5) and (4) sealing and storing the kneaded material for 24 hours, and then putting the kneaded material into an extruder to extrude and form a graphite tube.

In the preparation method of the carbon fiber reinforced compression type graphite tube, before the material in the step (4) is put into a kneading pot, the viscosity of the resin component prepared in the step (1) is kept at 1-4 minutes, before the material is put, the resin component is heated to 50-55 ℃ by using a water bath, and then the resin component is put into the kneading pot at one time; the kneading pot is controlled at 45 ℃ in summer and 75 ℃ in winter.

In the preparation method of the carbon fiber reinforced compression type graphite tube, in the step (5), the extrusion pressure of the extruder is 18Mpa, the temperature of a bin of the extruder is 50-60 ℃, the temperature of a machine head is 75-85 ℃, and the temperature of a nozzle outlet is 190-200 ℃.

The invention has the beneficial effects that: compared with the prior art, the carbon fiber reinforced compressed graphite tube and the preparation method thereof have the advantages that 5-50mm of short carbon fibers are added into the solid components of the compressed graphite tube in a filling mode, so that the skeleton reinforcing effect is formed, and the strength of the graphite tube is improved.

Pretreating the chopped carbon fibers by using a coupling agent (siloxane KH-560) by adopting a chemical grafting method; the linear carbon fiber is changed into a branch type, so that the anchoring effect is enhanced, and the strength, toughness, wear resistance, size stability, shock resistance and vibration resistance of the graphite tube are improved.

The epoxy resin is used as a compatilizer and a toughening agent to improve the brittleness of the graphite tube and improve the bonding performance of various materials.

The carbon fiber reinforced compressed graphite pipe has the advantages that the acid corrosion resistance of the phenolic resin compressed graphite pipe is improved, and the alkali resistance and the solvent resistance are greatly improved.

The carbon fiber reinforced compression type graphite tube successfully introduces the high-performance elastomer component, and the maximum advantages of the carbon fiber reinforced compression type graphite tube are good toughness and plasticity.

Compared with the existing similar product 'externally wound carbon fiber reinforced graphite tube' in the market, the carbon fiber reinforced pressed graphite tube has the advantages of shorter manufacturing process route, less equipment investment and lower product cost price. The externally wound carbon fiber reinforced graphite pipe is only used for reinforcing the annular direction, and the product is reinforced in an all-dimensional manner and has higher performance stability. Thereby greatly improving the thermal shock resistance, abrasion resistance and fracture resistance of the graphite heat exchanger and expanding the application range of the graphite tubular heat exchanger in the environments of high temperature, high pressure and the like. There is a well established experience in the use of evaporators, and the performance and service life of the evaporator are not comparable to those of equipment using ordinary graphite heat exchange tubes.

At present, no carbon fiber reinforced compression type graphite tube product produced by a compression molding method exists at home and abroad, and the project is a unique technical product. The successful development of the carbon fiber reinforced compression type graphite pipe breaks through the technical barriers abroad, solves the key technical problem of domestic replacement of imported graphite equipment, and has staged historical significance. The domestic graphite heat exchanger technology is close to the foreign technology by one step. Promotes the upgrade of the domestic graphite tubular heat exchanger. The historical technical problem that the heat exchange tube of the graphite heat exchanger is poor in strength and toughness is thoroughly solved.

Graphite tube type heat exchangers such as phosphoric acid heaters are key equipment in a wet-process phosphoric acid concentration device, and graphite tubes and joints of the graphite tubes and tube plates are prone to cracking due to heating steam pressure fluctuation and the like. The carbon fiber reinforced graphite tube has the characteristics that the working temperature and the working pressure are higher than those of a common compression graphite tube, the service life is long, and the reliability is high.

The carbon fiber reinforced compression type graphite tube and the preparation method are based on the existing compression type graphite tube manufacturing process and production equipment, the original operation process method of key procedures such as graphite tube extrusion molding and the like is not changed as far as possible, equipment of key procedures such as extrusion molding, mixing and kneading ingredients and the like is not changed, and the operation habits of important procedures are not changed. The production and manufacture of "pressed graphite tubes" is a practical technique that requires a high degree of practical skill from the operator. The working experience and the technical level of operators are key factors for ensuring the quality and the performance of the graphite tube product. Therefore, the stability of the operation method of the extrusion molding process is kept, and the operation skills which are groped and mastered by the existing operators for a long time are fully utilized, which is a crucial factor. And the method also is a powerful guarantee for smoothly converting the research and development results into large-scale production.

With the development trend of industrial scale, the graphite heat exchanger is also developing towards large scale, the common compression type graphite pipe can not meet the production requirement, and the enhanced graphite pipe is a necessary material for manufacturing large-scale tube equipment.

The carbon fiber reinforced compression type graphite tube and the preparation method thereof have the advantages that the tensile strength is 1.33 times of that of a common tube and 1.13 times of that of an impregnated graphite tube through all-round tests, and the test data are shown in Table 1

Numbering	Name (R)	Maximum power (KN)	Strength (MPa)
				1	Pressed graphite tube 1	7.08	7.49
2	Reinforced graphite pipe (non-heat treatment)	31.81	33.6
				3	Pressed graphite tube 2	20.52	21.71
4	Enhanced graphite pipe (after heat treatment)	27.76	29.37
				5	Pressed graphite tube 3	23.19	25.23
6	Graphite impregnated tube	26.19	27.71

The carbon fiber reinforced compression type graphite tube and the preparation method thereof have the following experimental steps of:

(1) piece 4 was sampled from the tube.

(2) Weighing: the total weight was 10.9993 g.

(3) Acid cooking: according to the mature acid boiling process, the sample is placed into a container, 60% phosphoric acid is added, and the mixture is heated until the acid liquor is boiled and kept for 96 hours. (the sample pieces were placed in the reaction flask without being taken out even though continuous heating was not possible.)

(4) After the reaction is finished, the sample block is taken out and put into a drying oven to be dried, and the temperature is kept at 160 ℃ for more than 2 hours.

(5) Repeating: it was found to be 11.0182 g.

(6) And (3) experimental observation: the color of the acid solution is unchanged after acid cooking, but white substances are generated on the surface of the sample block, the measured weight is increased by 0.0189g, and the weight gain ratio is 0.17%. The white substance should be analyzed to be CaSO₄。

Accordingly, the corrosion resistance of the new pipe can be judged to be acceptable.

In summary, aiming at the defects in the prior art, in order to improve the product quality stability of the graphite tube-type heat exchanger and manufacture a high-end graphite heat exchanger with more excellent performance, the invention seeks a solution to the defects of the traditional graphite heat exchange tube, develops a new product of the carbon fiber reinforced compression type graphite tube with high toughness and high strength, and fills the technical blank of graphite equipment manufacturing enterprises in the field of high-end graphite products. The product is mainly applied to the fields: the heat exchanger comprises a large tubular heat exchanger, a graphite tubular phosphoric acid evaporator, a middle-high end graphite heat exchanger with relatively harsh working conditions and high stability requirements, a graphite condenser, a high-pressure tubular heat exchanger, a graphite pipeline and the like.

The carbon fiber reinforced compression type graphite tube and the preparation method mainly solve the defects that the traditional graphite heat exchange tube is a brittle material, and improve the overall performance of the graphite tube heat exchanger by improving the strength, toughness and dimensional stability of the graphite heat exchange tube.

At present, no carbon fiber reinforced graphite tube product produced by a compression molding method exists at home and abroad, and the carbon fiber reinforced compression graphite tube and the preparation method thereof are unique technical products at the present stage. The novel graphite heat exchange tube has the advantages of stable quality, excellent performance, low manufacturing cost and simple manufacturing process. The high-strength high-toughness high-strength high.

The carbon fiber reinforced compression type graphite tube and the preparation method thereof complete processes of small test, pilot test, practice verification and the like at present and are successful. In 2019, 10 and 22 months, the carbon fiber reinforced compression type graphite tube for the graphite tube heat exchanger successfully completes the conversion of research and development results, and the technology is grounded. The method is successfully applied to the Hubei Yihua 780 square graphite tube-array evaporator, has no problems in use so far, prolongs the service life by 1.5 times compared with the traditional equipment, and has basically equivalent overhaul period to foreign products. The technical problem that the same type of products can not meet the high-temperature and high-pressure process conditions is solved, and the problem does not occur after 19 months of operation.

FIG. 1 is a first reaction process in the preparation of phenolic resin;

FIG. 2 is a second reaction step in the preparation of phenolic resin;

FIG. 3 shows a third reaction step in the preparation of phenolic resin.

Detailed Description

The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.

Example 1 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 20g of phenolic resin, 2g of epoxy resin, 1g of zinc chloride, 6g of nitrile rubber, 6g of carbon fiber, 6g of siloxane, 200g of ethanol and 65g of graphite powder.

Example 2 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 30g of phenolic resin, 6g of epoxy resin, 3g of zinc chloride, 12g of nitrile rubber, 12g of carbon fiber, 12g of siloxane, 400g of ethanol and 85g of graphite powder.

Example 3 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 25g of phenolic resin, 4g of epoxy resin, 2g of zinc chloride, 9g of nitrile rubber, 9g of carbon fiber, 9g of siloxane, 2300g of ethanol and 75g of graphite powder.

Example 4 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 20g of phenolic resin, 6g of epoxy resin, 2g of zinc chloride, 9g of nitrile rubber, 9g of carbon fiber, 9g of siloxane, 300g of ethanol and 75g of graphite powder.

Example 5 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 30g of phenolic resin, 2g of epoxy resin, 2g of zinc chloride, 9g of nitrile rubber, 9g of carbon fiber, 9g of siloxane, 300g of ethanol and 75g of graphite powder.

Example 6 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 22g of phenolic resin, 5g of epoxy resin, 1g of zinc chloride, 10g of nitrile rubber, 8g of carbon fiber, 8g of siloxane, 250g of ethanol and 70g of graphite powder.

Example 7 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 28g of phenolic resin, 3g of epoxy resin, 3g of zinc chloride, 10g of nitrile rubber, 7g of carbon fiber, 7g of siloxane, 240g of ethanol and 70g of graphite powder.

Example 8 of the invention: a carbon fiber reinforced compression type graphite tube is prepared from the following raw materials in parts by weight: 24g of phenolic resin, 5g of epoxy resin, 2g of zinc chloride, 8g of nitrile rubber, 10g of carbon fiber, 10g of siloxane, 350g of ethanol and 75g of graphite powder.

In the above embodiments, the graphite powder is made of high-purity graphite, and the graphite content is greater than or equal to 99.9%. The preparation method of the graphite powder comprises the following steps: the proportion of 30-60 meshes of graphite powder is 2/3, and the proportion of 80-100 meshes of graphite powder is 1/3. Test verification: the graphite powder is prepared according to the particle size ratio in the range, so that the volume filling ratio of the solid can be ensured to be higher, and the best strength of the liquid and solid mixed bonding material (pouring) can be effectively improved. The zinc chloride is a reagent grade commercial product, and the purity of the zinc chloride is more than or equal to 99.9 percent. The nitrile rubber is industrial grade 80-mesh nitrile rubber powder sold in the market, and the purity is more than or equal to 99.9%. The siloxane is a reagent grade commercial product, and the purity of the siloxane is more than or equal to 99.9 percent. Ethanol is a reagent grade product sold in the market; the purity is more than or equal to 99.9 percent. The fiber is a commercial product of high-modulus carbon fiber, the length of the carbon fiber is 5-50mm, and the purity of the carbon fiber is more than or equal to 99.9%. Tests prove that the fiber in the specification range is the optimum range of uniform dispersion and agglomeration reduction in the mixing process, and the anchoring, pulling and reinforcing effects in use are considered.

The phenolic resin and the epoxy resin are prepared by the following method. Specifically, the phenolic resin manufacturing process method comprises the following steps:

the concrete raw materials comprise the following components in parts by mass: phenol: formaldehyde: sodium carbonate 100: 45: 1.

(1) and (3) dissolving phenol into liquid from the crystal, heating a phenol barrel by using steam at the temperature of 80-100 ℃ so as to dissolve the phenol, and then putting the phenol into a reaction kettle.

(2) Respectively adding the metered phenol and formaldehyde into a reaction kettle, keeping the temperature in the kettle at 35-40 ℃, stirring for 10-15 minutes, opening an atmospheric valve before stirring, and stopping for 2-3 minutes after stirring uniformly.

(3) Adding the measured sodium carbonate catalyst into the kettle, closing all valves, starting stirring and heating, wherein the stirring and heating speed is 1 ℃/min and cannot exceed 1.5 ℃/min at most, and stirring and heating to 85 ℃. Stopping heating and stirring at 85 deg.C, opening atmospheric valve and reflux valve, and waiting for reflux. At this time, the polymerization reaction started and the reaction was accompanied by heat generation, so that the temperature in the reactor gradually increased.

(4) Phenol reacts with excess formaldehyde under the action of an alkaline catalyst to produce a phenolic resole resin. Because of the influence of the phenolic hydroxyl groups, ortho-and one para-position on the phenolic nucleus is activated, and these active positions, when attacked by formaldehyde, produce ortho-and para-hydroxymethylphenols, the reaction of which is shown in FIG. 1.

In addition to reacting with phenol, hydroxymethylphenol may also continue to react with formaldehyde to produce polyhydroxymethylphenol, as shown in FIG. 2.

The methylol phenol reacts with phenol or with each other to produce a phenolic resin of linear structure, as shown in FIG. 3.

(5) Observing the rising temperature, generating reflux when the temperature of the kettle rises to 100-105 ℃, and returning the reflux to the reaction kettle through the condenser. Stirring and heating are not started within 20 minutes when the reflux is started, so that the reflux is naturally performed, the stirring is started after 20 minutes, and the reflux is performed under the condition of constant temperature by controlling a heating device, wherein the reflux time is 150-210 minutes.

(6) When the stirring reflux is close to the end point, samples are taken every 10 minutes, and the reflux time is controlled according to the water stratification. The resin to water layering ratio is 2: the end of the polymerization was reached at 1 hour and the reflux time was over.

(7) And when the polymerization end point is reached, continuing stirring, opening cooling water to reduce the temperature, and adding 36 mass percent hydrochloric acid to neutralize until the pH value is 7 when the kettle temperature reaches 60 ℃.

(8) The resin was washed with water in an amount of about 1.5 times the volume of the resin to wash out the salt in the resin.

(9) Standing for layering, removing water layer, closing reflux valve, opening dehydration valve, and preparing for dehydration.

(10) Vacuum dehydration is carried out. The vacuum degree reaches 0.085-0.095 MPa, the sample is kept for 30-40 minutes for sampling and observation, and the dehydration time is 150-210 minutes.

(11) Sampling every 10 minutes, cooling to 20 ℃ to observe whether the resin is transparent or not, and when the detection indexes are as follows: the dehydration end point is determined when the water content is less than or equal to 8 percent and the viscosity is 90 'to 300'.

(12) Closing the dewatering valve, stopping the vacuum pump, continuing stirring, opening cooling water, cooling to 30-35 ℃, taking the resin out of the kettle, filtering, and storing in a resin storage tank for later use.

The preparation process method of the epoxy resin comprises the following steps:

the raw materials comprise: epichlorohydrin, bisphenol A, sodium hydroxide, benzene and deionized water.

The concrete raw materials comprise the following components in parts by mass: epoxy chloropropane: bisphenol A: sodium hydroxide: benzene: 100 parts of deionized water: 126: 33: 438: 219.

specifically, the manufacturing process method of the epoxy resin comprises the following steps:

(1) firstly, completely pumping the epoxy chloropropane into a reaction kettle, and then pumping the bisphenol A into the reaction kettle to ensure that the bisphenol A is distributed on the epoxy chloropropane.

(2) And introducing steam to ensure that the temperature in the reaction kettle reaches 70 ℃ and the bisphenol A is completely melted for about 20 minutes. Starting the stirrer, continuously stirring, heating to 75 ℃, and turning off steam.

(3) Dissolving sodium hydroxide into an aqueous solution with the mass concentration of 20%, and then slowly dropwise adding the aqueous solution of sodium hydroxide into the reaction kettle at the dropping speed of 5-8 drops per minute.

(4) The dropping speed is controlled by observing the temperature change, the temperature of the reaction kettle is ensured not to exceed 75 ℃ in the dropping process, the temperature is optimal to be 73-74 ℃, the flow rate is slow at the beginning of the dropping process, the flow rate can be properly increased after one hour, and the total time is about 6 hours.

(5) After the dropwise addition, the stirring was continued for 1 hour and 30 minutes, and the temperature of the reaction kettle was maintained at 74 ℃ to 75 ℃ by keeping the steam introduced. Turning off the heating steam, and carrying out first water washing when the temperature in the kettle is reduced to 60 ℃.

(6) 57 percent of the total feeding amount of the benzene is added into a high-level tank, and the following materials are forbidden during feeding: benzene was charged to the kettle under vacuum.

(7) And starting a condensing system, and adding the benzene liquid in the high-level tank into the reaction kettle. 60% of the total charge of deionized water was added to the overhead tank.

(8) Stirring was continued for about 30 minutes, followed by 50 minutes of quiescent stratification. And opening a kettle bottom valve, discharging a water layer, and carrying out secondary water washing. Adding the rest benzene and deionized water, and the operation steps are the same as above; if the washing effect is not obvious, the third washing can be carried out. And only adding deionized water for the third washing, and if the third washing is needed, weighing the deionized water for the third washing.

(9) And (3) distillation: at the temperature below 30 ℃ (normal temperature), a vacuum system is started to evaporate the benzene liquid, the flow rate of the reflux liquid is observed, and the reflux liquid is optimally stable and slowly flows down along the visual clock wall. When the reflux of the condensate is less, slowly raising the temperature of the reaction kettle, continuously controlling the reflux amount, and stopping heating until the kettle temperature is about 70 ℃ until the reflux is basically stopped. The reflux cooling adopts secondary cooling, and the secondary cooling is adopted, so that the benzene vapor is condensed and collected to the maximum extent, and the benzene vapor is prevented from being emitted into the air.

(10) Discharging (the finished product is golden yellow like soybean oil), and recovering benzene liquid for treatment.

The preparation method of the carbon fiber reinforced pressed graphite tube in each of the above embodiments is as follows:

(1) preparation of the resin component: putting phenolic resin and epoxy resin into a container, heating the container, keeping the temperature at 50 ℃, continuously stirring for 30 minutes, and then keeping for later use;

(2) carbon fiber treatment: the carbon fibers were treated by a soaking method using siloxane (3% of silane 560 coupling agent) and ethanol for 3 to 6 hours, and then air-dried for use. The carbon fiber size specification is as follows: chopped fibers having a length of 5 mm.

(3) Adding zinc chloride, nitrile rubber, graphite powder and air-dried carbon fibers into a mixer, uniformly mixing and stirring, then discharging, screening and separating, manually breaking the large particles into lumps, and mixing in the mixer;

(4) and (4) putting the materials in the step (1) and the step (3) into a kneading pot for kneading for 50-70 minutes. Before the materials are put into a kneading pot, the viscosity of the resin component prepared in the step (1) is kept between 1 and 4 minutes, and the viscosity can be tested by adopting a ball drop method. Before feeding, heating the resin components to 50-55 ℃ by using a water bath, and then feeding the resin components into a kneading pot at one time; the kneading pot is controlled at 45 ℃ in summer and 75 ℃ in winter.

(5) And (4) sealing and storing the kneaded material for 24 hours, and then putting the kneaded material into an extruder to extrude and form a graphite tube. The extrusion pressure of the extruder is 18Mpa, the bin temperature of the extruder is 50-60 ℃, the head temperature is 75-85 ℃, and the outlet temperature of the nozzle is 190-200 ℃. The material should be used up within 6 hours.