JPH0531469B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides at least one adherend material selected from carbon, graphite, or their precursors;
A heat-resistant adhesive structure comprising an adhesive layer mainly made of a carbide or graphite compound of an adhesive made of a thermosetting composition, wherein the adhesive layer and the adherend have the same coefficient of thermal expansion. The present invention relates to a carbon and graphite bonded structure suitable for structures and a method for manufacturing the same. (Prior Art) Several types of carbon and graphite adhesives have been known and are commercially available, but at present no details have been published. These adhesives can be roughly classified as follows. (1) Carbon, graphite, or their precursors are used as aggregates, and thermosetting resins such as phenolic resins, epoxy resins, and furan resins are mixed as B-stage resins. (2) Aggregates made of carbon, graphite, or their precursors, mixed with a mixture of petroleum-based or coal-based tar, pitch, and B-stage thermosetting resin similar to (1). Among these, for (1), the product name V58a (manufactured by SIGRI in West Germany) is commercially available, and for (2), the product name Newcoat GC (American DYLON) is commercially available.
INDUSTRY INC.) is commercially available, and ``Tar-containing adhesive for refractory bricks'' is disclosed in Japanese Patent Application Laid-Open No. 114543/1983. (Problems to be Solved by the Invention) First, the carbon and graphite adhesive described in (1) above has the drawback that the carbonization yield of the cured resin is low, and the carbon of the adhesive Since the carbonization shrinkage is extremely large, the adhesive strength after carbonization is extremely low when no aggregate is added.For this reason, the adhesive thickness depends on the aggregate particle size, and high dimensional accuracy cannot be obtained. Furthermore, it was not possible to change the coefficient of thermal expansion of the adhesive layer after carbonization or graphitization. Therefore, the obtained bonded structure had the disadvantage of being susceptible to thermal shock. Next, in the carbon and graphite adhesive mentioned in (2), since the carbonization yield of the thermosetting resin is low, tar and pitch, which have a high carbonization yield, are added in an attempt to solve this drawback. be done. However, since pitch is inherently thermoplastic, there is a limit to the amount that can be added, and if too much is added, the adhesive layer will foam or soften during the carbonization process, so a fundamental solution cannot be reached, resulting in low adhesive strength and Since the thermal expansion coefficient of the adhesive layer after carbonization and graphitization cannot be controlled, the thermal shock resistance of the bonded portion is extremely low. In addition, in both (1) and (2), the bond between the adherend and the adhesive relies on physical adhesion (anchor effect), and is not based on actively introducing chemical bonding. It cannot be said that properties such as thermal shock resistance, dimensional stability, strength, elastic modulus, and toughness of the structure are fully brought out. (Means and effects for solving the problems) The present invention uses, as an adhesive, a thermosetting composition that exhibits low shrinkage during curing, a high carbonization yield, and low shrinkage during carbonization. Therefore, the adhesive layer and the adherend are strongly bonded, and basically high adhesive strength can be obtained after carbonization and graphitization without any aggregate.
Therefore, the adhesion accuracy is several μm, which is the same as precision machining.
Orders can be secured. In addition, by changing the composition of the thermosetting composition, the type of aggregate, and the amount added, it is possible to control the coefficient of thermal expansion of the adhesive layer of the resulting adhesive structure and make it match that of the adherend. Therefore, it is suitable for heat-resistant parts such as jigs, crucibles, heaters, etc., parts for chemical reaction devices that require complicated processing, parts for heat exchangers, etc., which are characterized by improving the thermal shock resistance of bonded structures. The object of the present invention is to provide a bonded structure made of carbon and graphite, and the above object can be achieved by providing the bonded structure made of carbon and graphite and the manufacturing method thereof according to the claims. . Next, the present invention will be explained in detail. That is, the present invention provides that an adherend made of carbon, graphite, or a precursor thereof mainly has two or more fused polycyclic aromatic compounds having two or more rings and at least one of a hydroxymethyl group and a halomethyl group. A thermosetting composition (hereinafter abbreviated as COPNA resin composition) formed by reacting a mixture of an aromatic crosslinking agent consisting of one or two or more aromatic rings with an acid catalyst, whose main component is a carbide or graphitized product. The present invention relates to a carbon or graphite adhesive structure comprising an adhesive layer, the adhesive layer and an adherend having the same coefficient of thermal expansion, and a method for manufacturing the same. The coefficient of thermal expansion of the adhesive layer containing carbide or graphitized material as a main component can be controlled according to the coefficient of thermal expansion of the adherend by a combination of the following four methods. (1) Use a condensed polycyclic aromatic compound containing at least one element of oxygen, sulfur, or halogen in the molecule, or add sulfur to the adhesive. (2) Use carbon precursor as aggregate. (3) Carbon, graphite, and expanded graphite are used as aggregates. (4) Change the heat treatment temperature of the bonded structure. Among these, (1) and (2) have the effect of increasing the thermal expansion coefficient of the adhesive layer containing carbide or graphitized material as a main component, and (3) and (4) have the effect of lowering it. By appropriately changing the presence, type, and amount of these additives, as well as the heat treatment temperature, it is possible to change the thermal expansion coefficient of the adhesive layer after graphitization at a temperature of, for example, 2800°C.
It can be controlled over a wide range of 2.0 to 8.0×10 ^-6 /°C (50 to 400°C). Further, the adhesive strength of an adhesive layer containing an additive or a graphitized material as a main component is dramatically improved when a surface functional group is present on the surface of the adherend before adhesion. Thermal shock resistance is mainly controlled by strength, thermal conductivity, modulus of elasticity, and coefficient of thermal expansion. In the case of adhesive structures, it is most important that the adherend and the adhesive layer have the same coefficient of thermal expansion, and secondly, high adhesive strength improves thermal shock resistance. As an adhesive, the softening point and melt viscosity of the so-called B-stage resin can be controlled over a wide range by changing the reaction conditions for producing the thermosetting intermediate reaction product. In particular, by using heavy oil and pitch-based condensed polycyclic aromatic compounds,
Carbonization yield is dramatically improved. In this case, the condensed polycyclic aromatic molecules that make up the heavy oil and pitch react directly with the aromatic crosslinking agent to form a thermosetting resin, which not only improves the carbonization yield but also reduces shrinkage during carbonization. It has small characteristics. Due to these effects, it has thermal shock resistance, dimensional stability, strength, and toughness, and
It is possible to obtain a bonded structure made of carbon or graphite, which has excellent bonding dimensional accuracy, is not limited in size or shape, and cannot be obtained by conventional machining. Hereinafter, the fused polycyclic aromatic compound, aromatic crosslinking agent, and acid catalyst, which are raw materials for the thermosetting composition of the present invention, will be explained. The fused polycyclic aromatic compound of the present invention has two or more rings,
Naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, acenaphthylene,
One or a mixture of two or more selected from derivatives with main skeletons of perylene and coronene, coal-based or petroleum-based heavy oil, tar, pitch, or oxides, sulfides, or halides of the above substances. Can be used. Furthermore, the oxygen, sulfur, or halogen contained therein may be present alone, as a functional group, or within a ring, and the number thereof is not limited. These oxygen, sulfur or halogens are
In addition to the methylene crosslinks that make up COPNA resin, these elements form three-dimensional crosslinks in the adhesive layer by dehydrogenation, so the coefficient of thermal expansion of the adhesive layer after carbonization and graphitization is It has the effect of enlarging it. Next, the crosslinking agent of the present invention includes an aromatic compound consisting of one or more aromatic rings having two or more of at least one of hydroxymethyl group and halomethyl group, such as p-xylylene dichloride, , 4-benzenedimethanol (p-xylylene glycol) or derivatives thereof can be used. In addition, the acid catalyst of the present invention includes aluminum chloride,
One or a mixture of two or more selected from Lewis acids such as boron fluoride, protonic acids such as sulfuric acid, phosphoric acid, organic sulfonic acids, and carboxylic acids, and derivatives thereof can be used. The fused polycyclic aromatic compound, crosslinking agent, and acid catalyst are
Regarding the mixing ratio for forming a COPNA resin composition, crosslinking agent/condensed polycyclic aromatic compound = 0.5 to 4.0
(molar ratio) range; the amount of acid catalyst added is based on the mixture of crosslinking agent/fused polycyclic aromatic compound.
A suitable range is 0.5 to 10 wt%. In addition, B
The reaction temperature range for obtaining the stage adhesive is preferably 60 to 300°C. In the manner described above, a so-called B-stage resin adhesive can be obtained by subjecting the COPNA resin composition to a heat reaction. Further, when sulfur or dinitronaphthalene is added to this B-stage resin adhesive, the amount added is preferably in the range of 0.5 to 10 wt%. Although the addition method may be by mixing powder, it is preferable to use a solvent such as carbon disulfide. The adhesive layer of the present invention uses carbon, graphite,
Expanded graphite, natural or synthetic polymers or precursors thereof can be used. In addition, the surface functional groups of the aggregate include hydrogen, halogen, hydroxyl group, carbonyl group, carboxyl group, aldehyde group, epoxy structure, kraton structure, ether structure, acid anhydride structure, etc.
It has the effect of strengthening the bond between COPNA resin and aggregate. On the other hand, when the same amount of aggregate is added, the coefficient of thermal expansion of the adhesive layer tends to decrease as the number of these surface functional groups decreases or as the thermal history temperature of the aggregate increases. The coefficient of thermal expansion decreases in the order of > graphite > expanded graphite. Further, the particle size of the aggregate is preferably 10 μm or less from the viewpoint of adhesive accuracy, and the amount added is not particularly limited, but is preferably in the range of 1 to 50 wt% based on the B-stage resin. As a method of addition, a method of mixing it into the COPNA resin composition before the heating reaction or a method of mixing it into the B-stage resin after the reaction can be used. The adherend of the present invention (1 in Fig. 1) is carbon,
Graphite or a precursor thereof can be used. Regarding adherends, if surface functional groups such as hydrogen, halogen, hydroxyl group, carbonyl group, carboxyl group, aldehyde group, epoxy structure, lactone structure, ether structure, acid anhydride structure, etc. are present on the adherend surface, carbonization may occur. , the adhesive strength after graphitization is significantly improved. For this reason, chemical introduction such as nitric acid treatment or introduction by oxygen gas plasma treatment (2 in FIG. 1) is suitable. If surface functional groups exist on the surface to be adhered in this way, apply a solution of a mixture of an aromatic crosslinking agent and an acid catalyst, such as alcohol, to the surface before adhesion. This further improves the adhesive strength. The adhesive operation is performed at room temperature if the B-stage COPNA resin composition (3 in Figure 1) is liquid at room temperature, or at 20 to 60 degrees below the softening point if it has a softening point.
After applying the adhesive to the surfaces to be adhered to at a high temperature of .degree. C., the surfaces to be adhered to each other are bonded together (3d in FIG. 1), and the adhesive is thermally cured. At this time, in order to obtain high adhesion accuracy,
It is preferable to fix the adhesive part with a jig. Thermal curing temperature range is 100-400℃, preferably
150-250°C is suitable. Carbonization after curing (4 in Figure 1) is carried out in a non-oxidizing atmosphere by raising the temperature from 600 to 1500°C at a temperature increase rate of 400°C/hr or less, preferably 100°C/hr or less. Graphitization (5 in Figure 1) is also carried out in a non-oxidizing atmosphere by raising the temperature to 2000-3000°C at a rate of 600°C/hr or less, preferably 200°C/hr or less. As described above, the jig has thermal shock resistance, dimensional stability, strength, and toughness, and has excellent adhesion dimensional accuracy, regardless of size or shape.
It is possible to provide heat-resistant parts such as crucibles and heaters, parts for chemical reaction equipment that require complicated processing, parts for heat exchangers, etc., and carbon and graphite bonded structures in shapes that could not previously be obtained by machining. . (Example) Next, the present invention will be described in more detail with reference to Examples. Example 1 Coal-based pitcher with a softening point of 85°C (average molecular weight approximately 400)
is a fused polycyclic aromatic compound, and p- is used as a crosslinking agent.
Xylene glycol (PXG) in a molar ratio of 1:2
A mixture of p-toluenesulfonic acid (PTS) and 5 wt% of p-toluenesulfonic acid (PTS) was reacted at 140° C. for 40 minutes to obtain a B-stage COPNA resin adhesive. As the adherend material, trade name T-6 (graphite material manufactured by IBIDEN Co., Ltd.) was used (Fig. 1a), and a 2 cm ² adherend surface was polished and a test piece was used which was ultrasonically cleaned in acetone. The adhering surface of the adherend material is CFS- manufactured by Tokuda Seisakusho Co., Ltd.
Pressure with 8EP-55 plasma sputtering device
Oxygen gas plasma treatment was performed at 0.3 mbar and an output of 500 W for 3 hours (Fig. 1b). Ethanol solutions of p-xylylene glycol and p-toluenesulfonic acid (concentrations: 0, 2.5,
5.0, 7.5wt%) was applied by spray and heated to 150℃. Applying the adhesive to the heated adhering surface (first
After Figure c), the adhesive was bonded (Figure 1D), the adhesive part was fixed with a graphite jig, and heated at 180°C for 40 minutes to harden the adhesive. Carbonization was carried out by heating the bonded part with a graphite jig in a non-oxidizing atmosphere at a temperature increase rate of 50 °C/hr to 100 °C (Fig. 1e), and graphitization was performed in the same manner for 3000 °C. ℃ (Fig. 1f). Further, the same operation was performed on a sample that was not subjected to oxygen gas plasma treatment. The tensile strength of the samples after carbonization and graphitization was measured. These results are shown in Table 1.

[Table] Example 2 Coal-based pitch with a softening point of 235°C and purified methylnaphthalene were mixed at a weight ratio of 1:2 to form a condensed polycyclic aromatic compound, and p-xylylene glycol was added as a crosslinking agent to the mixture by weight ratio. p-toluenesulfonic acid was added to this mixture at a ratio of 1:0.8.
10 wt%, 5 wt% sulfur, and 30 wt% of coal-based raw coke crushed to 5 μm or less as aggregate were added, and reacted at 120°C for 15 minutes to produce the B-stage.
COPNA resin adhesive was obtained. Using trade name T-4 and ET10 (graphite material made by IBIDEN Co., Ltd.; tensile strength of both approximately 200 Kg/cm ² ) as adherend materials, the 2 cm ² adhering surface was polished and then super-absorbed in acetone. A test piece that had been sonicated was used. Applying the adhesive at room temperature to the adherend surface of the adherend,
After adhesion, it was fixed with a metal jig and heated at 180°C for 60 minutes to harden the adhesive. After curing, the jig was removed and the temperature was raised to 1000°C at a rate of 30°C/hr in a non-oxidizing atmosphere to carbonize the bonded portion. In addition, test pieces were prepared in the same manner using an adhesive that did not contain aggregate. After carbonizing the sample, the thickness of the adhesive layer was measured using an optical microscope, and then the tensile strength of the bonded portion was measured. The results are shown in Table 2.

[Table] Example 3 Using adhesive a used in Example 1 and adhesive b in which 5 wt% sulfur was added to a, 10 μm of aggregate was used.
Three types of crushed coke (1) raw coal-based coke, (2) calcined coal-based coke, and (3) artificial graphite were each added at 30 wt% to the adhesive. Product names T-4, T-6 and ET10 (graphite material manufactured by IBIDEN Co., Ltd.) are used as adherends.
Thermal expansion coefficient (50~400℃) respectively (3.8, 4.8,
6.3×10 ^-6 /℃), a disk of 50 mmφ and 4 mm thickness with a hole of 8φ in the center was cut in half, and after bonding, the disk shape was prepared as shown in Example 1.
Carbonization was carried out after adhesion under the same conditions as above. After carbonization, the sample was heated at a heating rate of 400℃/hr in a non-oxidizing atmosphere.
The temperature was raised to 2000°C to graphitize the bonded area. After graphitization, the sample was sent to Fuji Denpai for the purpose of examining thermal shock resistance.
The outer periphery is rapidly heated using a high-frequency induction heating device manufactured by Co., Ltd.
The time until destruction was measured. The thermal shock resistance was evaluated by calculating the thermal shock resistance index FI shown in the following formula. FI=5.46+4.43ln (t/n) t: Power load time required for destruction n: Output coefficient 20KW 3.14 30KW 2.34 40KW 1.44 50KW 1.00 (The larger the FI value, the greater the thermal shock resistance.) This result is shown in the third section. Shown in the table.

[Table] (Effects of the Invention) As explained above, the carbon and graphite adhesive structure of the present invention has an adherend consisting of carbon, graphite, or a precursor thereof, which is mainly composed of a condensed polycyclic aromatic compound having two or more rings. A carbonized product of a thermosetting composition obtained by reacting a mixture of the aromatic crosslinking agent and an acid catalyst, which is composed of one or two or more aromatic rings having two or more of at least one of hydroxymethyl groups and halomethyl groups. Alternatively, it is an adhesive structure composed of an adhesive layer mainly composed of graphitized material, and is characterized in that the adhesive layer and the adherend have the same coefficient of thermal expansion. Alternatively, the coefficient of thermal expansion of the adhesive layer whose main component is graphitized material can be controlled over a wide range by appropriately changing the type and amount of additives such as aggregate and sulfur during manufacturing, as well as the heat treatment temperature. I can do it. Furthermore, the adhesive strength is dramatically improved when surface functional groups are present on the adhering surface of the adherend. The thermal shock resistance of the bonded structure of the present invention is extremely good because the adherend and the adhesive layer have the same coefficient of thermal expansion and high adhesive strength. Furthermore, by using heavy oil or a pitch-based condensed polycyclic aromatic compound, the carbonization yield can be dramatically improved. In this case, the condensed polycyclic aromatic molecules that make up the heavy oil and pitch react directly with the aromatic crosslinking agent to form a thermosetting resin, which not only improves the carbonization yield but also reduces shrinkage during carbonization. It has small characteristics and sufficient adhesive strength can be obtained even without aggregate. Therefore, adhesion accuracy comparable to precision machining accuracy can be obtained. Due to these characteristics, the bonded structure of the present invention has unprecedented thermal shock resistance, dimensional stability, strength, and toughness, as well as excellent bonding dimensional accuracy, and is not limited to size or shape. Heat-resistant parts such as jigs, crucibles, and heaters, parts for chemical reaction equipment with complex shapes, parts for heat exchangers, etc., as well as carbon and graphite structures with shapes that could not previously be obtained by machining. In addition to being able to supply the following, it is also possible to simplify processing steps that have been difficult to simplify in the past. These advantages enable significant cost savings;
The industrial effects are extremely large.

[Brief explanation of the drawing]

1A to 1F are steps for manufacturing the carbon and graphite bonded structure of the present invention. 1...Graphite adherend material, 2...Oxygen gas plasma,
3...Adhesive, 4...Carbide of adhesive, 5...Graphitized adhesive.

Claims (1)

[Scope of Claims] 1. At least one adherend material selected from carbon, graphite, or their precursors, and the following (a):
(b) An adhesive structure comprising an adhesive layer mainly composed of carbide or graphitized material obtained by firing a thermosetting composition formed by reacting the mixture of (b) and (c). . A carbon/graphite bonded structure, wherein the adhesive layer and the adherend have the same coefficient of thermal expansion. (a) A fused polycyclic aromatic compound mainly having two or more rings (b) An aromatic crosslinking agent consisting of one or two or more aromatic rings having two or more of at least one type of hydroxymethyl group or halomethyl group ( c) Acid catalyst. 2 The difference in thermal expansion coefficient between the adhesive layer and the adherend is 30
% or less, the carbon-graphite bonded structure according to claim 1. 3. The fused polycyclic aromatic compound having mainly two or more rings is one or a mixture of two or more selected from derivatives having a main skeleton of naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, acenaphthylene, perylene, and coronene. 2. The carbon or graphite adhesive structure according to claim 1, which is coal or petroleum-based heavy oil, tar, or pitch. 4. The carbon-graphite adhesive structure according to claim 1, wherein the fused polycyclic aromatic compound having mainly two or more rings contains at least one element selected from oxygen, sulfur, and halogen in the molecule. 5. The carbonaceous acid catalyst according to claim 1, wherein the acid catalyst is one or a mixture of two or more selected from aluminum chloride, boron fluoride, phosphoric acid, organic sulfonic acid, carboxylic acid, or derivatives thereof. , graphitic bonded structures. 6. The adhesive contains as an aggregate one or more compounds or mixtures selected from carbon, graphite, expanded graphite, natural or synthetic polymers, or their precursors. carbon, graphite bonded structure. 7. A method for producing a carbon-graphite bonded structure, comprising at least the following sequence of steps (a) to (c). (a) An aromatic crosslinking agent consisting mainly of a fused polycyclic aromatic compound having two or more rings and one or more aromatic rings having two or more of at least one type of hydroxymethyl group or halomethyl group; A thermosetting composition comprising an acid catalyst is heated at 60 to 300°C in an oxidizing or non-oxidizing atmosphere.
The process of heating to a temperature range of 150°C or less to produce an intermediate reaction product (B-stage resin) with a softening point of 150°C or less. (b) The intermediate reaction product (B-stage resin) obtained in step (a) above is applied as an adhesive to the adherend surfaces of the adherends, and after adhering the adherend surfaces together, oxidizing or non-oxidizing A process in which the adhesive is thermally cured by heating to a temperature range of 100 to 400°C in a neutral atmosphere. (c) A firing step in which the bonded structure obtained in step (b) is carbonized or graphitized in a non-oxidizing atmosphere. 8 The adhesive may contain carbon, graphite,
8. The manufacturing method according to claim 7, wherein one or more compounds or mixtures selected from expanded graphite, natural or synthetic polymers, or their precursors are mixed as an aggregate. 9 The adhering surface of the adherend before adhesion has at least one type selected from hydrogen, halogen, hydroxyl group, carbonyl group, carboxyl group, aldehyde group, epoxy structure, lactone structure, ether structure, and acid anhydride structure. The manufacturing method according to claim 7, which has a surface functional group. 10. The manufacturing method according to claim 7, wherein a surface functional group is introduced to the adhering surface of the adherend material by chemical reaction or plasma sputtering treatment before adhesion. 11. The manufacturing method according to claim 7, wherein the intermediate reaction product (B-stage resin) is used in the form of a solution dissolved in a bath agent. 12. The manufacturing method according to claim 7, wherein the fused polycyclic aromatic compound has at least one element selected from oxygen, sulfur, and halogen in the molecule. 13 The adhesive contains at least one selected from sulfur and dinitronaphthalene before adhesion.
The manufacturing method according to claim 7, wherein a seed is added.