JPH09314051A - Production of inner surface coated drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a productivity and to produce a low cost inner surface coated drum by applying a baking type coating material on an inner surface after injecting a flange of a mouth piece previously mounting a gasket to a top board and fixing the flange. SOLUTION: In a steel made drum used as a vessel for transporting and storaging of food, etc., and subjected to an inner surface coating, the flange 6 of the mouth piece is injected and fixed to the top board, and the gaskets 8 and 9 are mounted at the flange 6 and a plug 7. At the time of producing such the inner surface coated drum, the flange 6 of the mouth piece is injected and fixed to the top board, then the baking type coating material is applied on the inner surface. Then a body having a physical property of 5-12MPa tensile stress at 100% elongation and 14-30MPa tensile strength is used for the gaskets 8 and 9, and EPDM is preferably used for a main base stock. The base stock in which at least >=70wt.% of the EPDM before vulcanization has >=25ML1+4 (100 deg.C) Mooney viscosity is preferably used for the EPDM.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a steel drum with a spinneret having an inner surface coated, which is used as a container for transporting and storing chemical products, foods and the like.

[0002]

2. Description of the Related Art Generally, steel drums are roughly classified into two types. One of them is a closed type drum specified by JIS Z 1601 (steel drum for liquid), and the other is an open drum specified by JIS Z 1600 (steel open drum). FIG. 4 shows a conceptual diagram of the closed type drum. The closed drum consists of a top plate 1 and a base plate 2.
The top plate 1 has a large cap 4 and a small cap 5. Generally, the large cap 4 is an inlet, and the small cap 5 serves as an exhaust port.
Then, as shown in FIG. 5, both the large cap and the small cap of the mouthpiece are
A flange 6 is press-fitted and fixed to the top plate 1, and a plug 7 is fastened to the flange 6 with a screw. Further, gaskets 8 and 9 are attached to the flange and the plug, respectively, in order to ensure the hermeticity of the base portion.

The flange is made of steel and the surface thereof is zinc-plated or chrome-plated, and the plug is also made of zinc die-cast. Further, NBR (nitrile rubber), SBR (styrene butadiene rubber), polyamide resin, fluororubber is used as the flange gasket, and polyethylene, NBR, IIR (butyl rubber) is used as the gasket for the plug,
It is selected and used from among the fluororubbers, taking into consideration its suitability for drum contents and transport and storage conditions.

On the other hand, the open drum is a canopy from which the top plate 1 can be removed, and has a structure in which a band is fitted and the canopy is fastened to the body with bolts or levers.
In the case of an open drum, the canopy may or may not have a base. The closed drum is used to store chemical products and petroleum products in various liquid containers, and the open drum is used to store powder, solids and paints, adhesives, synthetic resins, and other viscous liquid containers. The capacity of the drum is 20 to 200 l for all types, but 200 l is overwhelmingly large.

Next, a method of manufacturing these drums will be described. First, the body is formed by forming a rectangular steel plate of a predetermined size into a cylindrical shape and then joining the seams together, and then two or more or more ring zones and the bridging process of both ends are performed. On the other hand, the top plate and base plate are stamped from a steel strip into a tray shape, and the base plate is stamped with the manufacturing date, manufacturing company name, and the like. Then, after punching and pressing the top plate for the die, a flange having a gasket attached in advance is press-fitted therein and fixed to the top plate by a die press-fitting machine continuously arranged. After that, the body, the top plate and the base plate are degreased and washed, and if necessary, chemical conversion treatment is performed. Then, in the case of the closed type, the top plate and the base plate are wound around the body, and in the case of the open drum, only the base plate is wound around, and the outer surface is painted with a melamine alkyd-based baking type paint, and finally the flange of the top plate is plugged. Is tightened to produce the drum.

[0006]

When the contents to be stored in these drums are corrosive or when it is desired to avoid contact with iron, the drum is made at the stage of three pieces of the body, top plate and ground plate. A drum formed by applying an epoxyphenol-based or phenol-based baking-type paint once or twice on the inner surface side and then winding and winding it is used. However, the baking condition after the inner surface coating is that the ambient temperature is 200 ° C to 230 ° C.
The holding time at that temperature is about 15 minutes, and the ambient temperature of ordinary melamine alkyd coating on the outer surface of the drum is 130.
The temperature is significantly higher than that of ℃ to 140 ℃ and holding time of 15 minutes. Therefore, the conventional flange gasket sufficiently withstands the high temperature at the time of baking after coating the outer surface, but causes a large permanent deformation at the baking temperature after coating the inner surface.

Therefore, when the inner surface is coated on the top plate having the flange press-fitted, the gasket is permanently deformed due to the high temperature during baking, and the sealing property between the flange and the top plate is impaired. Therefore, the inner surface coating drum is manufactured. In this case, the die is only punched and pressed, and the flange is not press-fitted.The top plate is painted internally and baked, and then the flange that has been pre-painted with the same paint as the drum body inner surface is placed offline with the die press-in machine. It was press-fitted. Therefore, the process of flange press-fitting processing on the top plate differs between the normal non-inner surface coating drum and the inner surface coating drum, and in the mass continuous production process of the drum, the process control becomes complicated and There is a problem that the flange press-fitting process is required even after coating, which increases the facility cost and the number of personnel, and the cost is increased by coating the flange inner surface of the drum in another process.

Therefore, the present invention solves the above-mentioned problems of the conventional method for manufacturing an inner surface coating drum, and provides a method for manufacturing an inner surface coating drum with good productivity and low cost. In addition, in the case of a drum, a baking type paint is used for both the inner surface coating and the outer surface coating, and baking is always performed after coating. Therefore, the painting in the description of the manufacturing process includes the baking process.

[0009]

DISCLOSURE OF THE INVENTION The present invention is a method for manufacturing an inner coating drum which has good productivity and is low in cost, as a result of intensive studies to solve such a problem. The gist of the invention is as follows: (1) A method for manufacturing an inner coating drum, which comprises press-fitting and fixing a flange of a die having a gasket mounted thereon to a top plate, and then coating a baking-type paint on the inner surface. (2) Tensile stress at 100% elongation is 5-12 MPa
And a gasket having physical properties of tensile strength of 14 to 30 MPa is attached to the flange. (3) The method for producing an inner coating drum according to (2) above, wherein a gasket whose main material is EPDM is attached to the flange.

(4) At least 70 of EPDM before vulcanization
Weight% or more is Mooney viscosity 25ML1 + 4 (100 ° C)
The method for producing an inner coating drum as described in (3) above, wherein the gasket made of the above materials is mounted on the flange. (5) The method for producing an inner coating drum according to the above (3), wherein a gasket prepared by vulcanizing EPDM with a mixture of peroxide and sulfur is attached to the flange. (6) A gasket made of a material having a combined amount of a softening agent, a plasticizer, a tackifier and a lubricant of 8% by weight or less of the entire gasket is mounted on the flange. Is a method for manufacturing an inner coating drum.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. 1 is a diagram showing a manufacturing process of an inner coating drum according to the present invention, FIG. 2 is a diagram showing a manufacturing process of a conventional inner coating drum, and FIG. 3 is a manufacturing process of a drum without inner coating. It is a figure. In the case of a normal drum without internal coating, the flange is press-fitted after the top plate is molded.
As shown in FIG. 2, in the conventional method for manufacturing an inner surface coating drum, the flange is not press-fitted in the top plate processing, but the flange is press-fitted after the inner surface is coated.

On the other hand, in the manufacturing process according to the present invention, the press-fitting process of the flange is performed in the same process as in the case of a usual drum without inner surface coating, and thereafter the inner surface coating is performed, so that the process is simple. Unlike the conventional method, it is not necessary to install another flange press-fitting processing facility off-line after the inner surface coating process and allocate personnel for the process.
Further, as the flange to be press-fitted into the top plate, a normal unpainted flange can be used, so that it is not necessary to previously paint the inner surface of the flange of the flange unlike the conventional inner surface coating drum.
As described above, in the method for manufacturing the inner surface coating drum according to the present invention, the press-fitting process of the flange is performed in the same process as in the case of the drum without the normal inner surface coating. Therefore, the flange press-fitting process is performed on the top plate after the conventional inner surface coating. The productivity is greatly improved compared to the method.

The present inventor has studied various conditions under which the gasket of the flange will not be permanently deformed by baking after coating the inner surface.
The tensile stress at 0% is 5 to 12 MPa and the tensile strength is at 14 to 30 MPa, and preferably the tensile stress at 100% elongation is 6 to 10 MPa and the tensile strength is at 15 to 15.
It has been found that when the pressure is 25 MPa, permanent deformation does not occur due to baking after the inner surface is coated, and good airtightness can be secured during normal use of the drum.

Since the flange of the drum is press-fitted and fixed to the top plate, the flange gasket located between them is subjected to a large compressive stress. Therefore, if the strength of the gasket is not sufficient, permanent deformation occurs when the gasket is heated to a high temperature by baking after coating the inner surface.
Therefore, as a result of investigating the strength of the gasket required to prevent permanent deformation by baking after the inner surface coating, the physical properties of the gasket are that the tensile stress at 100% elongation is 5 MPa or more, preferably 6 MPa or more, and the tensile strength is Is 14M
It has been found that harmful permanent deformation does not occur if it is Pa or higher, preferably 15 MPa.

On the other hand, the gasket is compressed and elastically deformed by the flange and the top plate, and the contact area between the gasket and the flange and between the gasket and the top plate becomes large, so that good sealing performance can be obtained. However, when the strength of the gasket is too large, this elastic deformation is not sufficient and good sealing performance cannot be obtained. Therefore, as a result of investigating the strength of the gasket required to obtain a good sealing property, the physical properties of the gasket are that the tensile stress at an elongation of 100% is 12 MPa or less,
Desirably 10 MPa or less and a tensile strength of 30 MP
It has been found that a good sealing property can be obtained if it is a or less, preferably 25 MPa or less. In addition, the above-mentioned elongation 10
Regarding the tensile stress and tensile strength at 0%, a vulcanized sheet with a thickness of 2 mm was made from the same material as the gasket and
It is a value obtained by performing a tensile test according to SK 6301 (vulcanized rubber physical test method), and measuring the tensile strength and the tensile stress when the elongation is 100% (the test piece used at this time is a tumbbell type 3).

[0016] As a result of various studies on the gasket material in order to achieve this object, it was concluded that EPDM is the best because permanent deformation of the gasket after baking of the inner surface coating is small. EPDM is a rubber obtained by vulcanizing a terpolymer of an unsaturated compound having a double bond with ethylene and propylene. Since it has almost no double bond or polar group in the molecular main chain, EPDM Chemical resistance, water resistance, compared to rubber
It has excellent resistance to oxidative deterioration and low temperature resistance and is the most excellent gasket material for drum caps. EPDM includes fillers, softeners, plasticizers, tackifiers, lubricants, stabilizers, antioxidants, vulcanizing agents, vulcanization accelerators,
A vulcanization accelerating aid and the like are added as necessary.

Further, in the case of a gasket made of EPDM, as a result of examining the conditions for obtaining the strength of the gasket described in claim 2, as a result of the increase in Mooney viscosity of EPDM before vulcanization, the gasket after vulcanization Of the EPDM before vulcanization has a Mooney viscosity of 25 ML1 + 4 (100 ° C.) or more, preferably all of the EPDM before vulcanization has a Mooney viscosity of 25 to 90 ML.
Within the range of 1 + 4 (100 ° C), the tensile stress at 100% elongation is 5 MPa or more, and the tensile strength is 14MP.
It was found that a or more can be secured. The Mooney viscosity is JIS K 6300 (unvulcanized rubber physical test method).
ML1 + 4 (100 ° C.), M is Mooney viscosity, L is rotor L type, 1 + 4 is preheating time 1 minute and rotor operating time 4 minutes, and (100 ° C.) is test temperature 100 ° C., respectively. There is.

There are two methods of vulcanizing EPDM. One is using sulfur and the other is using peroxide. However, those vulcanized with sulfur have a large permanent deformation when the gasket is compressed, and the drum is vulcanized. When a chemical having a high dissolving power is filled, coloring may occur in the drum contents, which is not suitable for the purpose of the present invention. On the other hand, those vulcanized with peroxide have good permanent deformation during compression, but insufficient tensile strength, and when the gasket is compressed by press fitting the flange to the top plate, Cracks may occur.

Therefore, as a result of various studies to eliminate the drawbacks of these vulcanization methods, when vulcanized with a mixture of peroxide and sulfur, permanent deformation during compression and coloring and cracking of drum contents occur. We found that they can be solved at the same time. And regarding the mixing ratio of peroxide and sulfur, peroxide 1
It is preferable that sulfur is 0.5 to 10 parts (weight ratio) with respect to 00 parts. On the other hand, when the drum is filled with highly soluble chemicals such as gasoline, toluene, butyl acetate, and methylene chloride, conventional rubber gaskets elute some components from inside the gasket, It was sometimes colored. Conventional rubber gaskets were vulcanized by sulfur, and in order to improve moldability, a large amount of softening agents such as process oil or plasticizers such as dioctyl phthalate were added. When a highly soluble chemical was filled, it was found that these softening agents, plasticizers, etc. were eluted from the gasket and colored the drum contents.

Therefore, if the total amount of the main components that are eluted from the gasket, that is, the softening agent, the plasticizer, the tackifier, and the lubricant is set to 8% by weight or less of the entire gasket, a chemical having a strong solubility in the drum is obtained. It has been found that even if filled with a chemical, coloring practically causes no problem. Note that if the amount of the softening agent or the plasticizer added is too small, molding of the gasket becomes difficult. Therefore, in practice, the total amount of the softening agent, the plasticizer, the tackifier, and the lubricant is 3 to 8 of the total amount of the gasket. It is preferably within the range of wt%. Also, for other compounding agents such as fillers, stabilizers, anti-aging agents, vulcanizing agents, vulcanization accelerators, vulcanization accelerating aids, etc., those that do not have the risk of coloring the drum contents must be selected. It goes without saying that it must be done.

[0021]

EXAMPLES Next, the method for manufacturing the inner surface coating drum of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. (Example 1) A flange gasket having the composition shown in Example 1 of Table 1 was produced. This gasket is 100
Tensile stress at 8% elongation is 8MPa, tensile strength is 20M
It was Pa, and both of them satisfied the condition of claim 2. Next, attach this gasket to the flange, and
An inner surface coating drum was manufactured by the process of the present invention shown in FIG. In this manufacturing method, the flange press-fitting process to the top plate is performed in the same process as the drum without the usual inner surface coating, and the flange and the top plate are simultaneously coated on the inner surface. Productivity is significantly improved compared to the method of press-fitting the flange in which the inner surface of the drum is painted in advance. It also realized the major advantage of not requiring double capital investment for press-fitting presses and double-positioning of press-fitting workers. Further, there is also an advantage that it is not necessary to paint the inner surface side of the flange of the drum in advance. And in the performance test of this drum, in the water pressure test, the drop test, the airtight test,
No leakage was observed between the flange of the base and the top plate. And the deformation of the gasket removed from the flange was also slight. Further, in the results of the immersion test of this gasket, coloring of the liquid was not observed with any of the four types of chemicals.

Example 2 A flange gasket having the composition shown in Example No. 2 in Table 1 was prepared. In this gasket, the Mooney viscosity of the unvulcanized rubber is lower than in Example 1, and the amount of the softening agent and the plasticizer combined and the amount of sulfur of the vulcanizing agent are small. The tensile stress and tensile strength at 100% elongation of this gasket were slightly lower than those of Example 1, but
Within the scope of claim 2. Next, this gasket was attached to the flange to manufacture an inner coating drum in the process of the present invention shown in FIG. As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. In the performance test of this drum, no leakage was observed between the flange of the mouthpiece and the top plate in the water pressure test, the drop test, and the airtight test. And the deformation of the gasket removed from the flange was also slight. Further, in the immersion test, no coloring was observed with any of the four types of chemicals.

(Example 3) A flange gasket having the composition shown in Example No. 3 of Table 1 was prepared. In this gasket, the unvulcanized rubber has a higher Mooney viscosity than in Example 1, the amount of the softening agent and the plasticizer combined is small, and the amount of sulfur in the vulcanizing agent is smaller than that in Example 2. 10 of this gasket
The tensile stress and tensile strength at 0% elongation were slightly higher than those in Example 1, but they are within the range of claim 2. next,
This gasket was attached to the flange, and an inner surface coating drum was manufactured by the process of the present invention shown in FIG. As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. In the performance test of this drum, no leakage was observed between the flange of the mouthpiece and the top plate in the water pressure test, the drop test, and the airtight test. And the deformation of the gasket removed from the flange was also slight. In addition, in the immersion test, no coloration of the liquid was observed with any of the four types of chemicals.

Example 4 A flange gasket having the composition shown in Example No. 4 of Table 1 was produced. In this gasket, the Mooney viscosity of the unvulcanized rubber was below the range of claim 4, and the tensile stress and tensile strength at 100% elongation were also below the range of claim 2. Next, by mounting this gasket on the flange, in the process of the present invention shown in FIG.
An inner coating drum was manufactured. This manufacturing method is the same as in Example 1.
As detailed in, productivity, capital investment,
There was a great advantage in terms of personnel. On the other hand, in the performance test of this drum, no leakage was found between the flange of the mouthpiece and the top plate in the drop test and the airtight test, but a leak was seen from the same part in the hydraulic test. Therefore, in the case of the present embodiment, the manufacturing method had a great advantage as compared with the conventional method, but in terms of the performance of the drum, leakage occurred in the water pressure test, so that the top plate and the ground plate of the drum were like drums. There is a limitation that it cannot be used in applications where extremely large internal pressure is applied such as swelling. In the immersion test, no liquid coloring was observed with any of the four types of chemicals.

Example 5 A flange gasket having the composition shown in Example No. 5 of Table 1 was prepared. The type and composition of this gasket are similar to those of Example 1, but the vulcanizing agent is only sulfur, and thus it does not conform to claim 5. The tensile strength of this gasket is below the range of claim 2. Next, attach this gasket to the flange, and
An inner surface coating drum was manufactured by the process of the present invention shown in FIG. As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. On the other hand, in the performance test of this drum, leakage was observed between the flange and the top plate in all of the water pressure test, the drop test, and the airtight test. Therefore, in the case of the present embodiment, the manufacturing method had a very great advantage as compared with the conventional method, but since leakage occurred in the hydraulic test of the drum, the drop test and the airtight test, when a large internal pressure was applied,
There is a limitation that it cannot be used in a case where it may fall from a high place and in an application that requires a high degree of airtightness. In addition, in the immersion test, yellow coloring was observed with all four types of chemicals, so there was a limitation that chemicals with strong dissolving power could not be filled.

Example 6 A flange gasket having the composition shown in Example No. 6 in Table 1 was prepared. The type and composition of this gasket are similar to those of Example 1, but the vulcanizing agent is only peroxide, which is not compatible with claim 5. And
The tensile stress and tensile strength at 100% elongation of this gasket were within the scope of claim 2, but the property of easy tearing was observed. Next, this gasket was attached to the flange to manufacture an inner coating drum in the process of the present invention shown in FIG. As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. On the other hand, in the performance test of this drum,
In the drop test and the airtight test, no leak was found between the flange and the top plate, but in the hydraulic test, a leak was seen from the same place. Therefore, in the case of the present embodiment, the manufacturing method had a great advantage as compared with the conventional method, but in terms of the performance of the drum, leakage occurred in the water pressure test, so that the top plate and the ground plate of the drum were like drums. There is a limitation that it cannot be used in applications where extremely large internal pressure is applied such as swelling. On the other hand, in the immersion test, no yellow coloring was observed with any of the four types of chemicals.

Example 7 A flange gasket having the composition shown in Example No. 7 of Table 1 was prepared. The type and composition of this gasket are similar to those of Example 1, but the peroxide and sulfur of the vulcanizing agent are 1 to 1, which is more than the ratio of 2 to 0.1 in the case of Example 1. The sulfur content is significantly higher. The tensile stress and tensile strength at 100% elongation of this gasket were within the scope of claim 2, but both were considerably lower than those of Example 1. Next, by mounting this gasket on the flange, in the process of the present invention shown in FIG.
An inner coating drum was manufactured. This manufacturing method is the same as in Example 1.
As detailed in, productivity, capital investment,
There was a great advantage in terms of personnel. On the other hand, in the performance test of this drum, no leakage was observed between the flange and the top plate in the drop test and the airtight test, but in the hydraulic test, leakage from the same place was observed. Therefore, in the case of the present embodiment, the manufacturing method had a great advantage as compared with the conventional method, but in terms of the performance of the drum, leakage occurred in the water pressure test, so that the top plate and the ground plate of the drum were like drums. There is a limitation that it cannot be used in applications where extremely large internal pressure is applied such as swelling. In addition, in the immersion test, all four types of chemicals were found to have a pale yellow coloration, so there was a limitation that chemicals that had a strong dissolving power and were not allowed to be colored slightly could not be filled.

Example 8 A flange gasket having the composition shown in Example No. 8 of Table 1 was prepared. The type and composition of this gasket is similar to that of Example 1, except that a softener,
The combined amount of the plasticizer, the tackifier and the lubricant is 11% of the entire gasket, which does not conform to claim 6. The tensile strength of this gasket was below the range defined in claim 2.
Next, this gasket was attached to the flange to manufacture an inner coating drum in the process of the present invention shown in FIG. As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. On the other hand, in the performance test of this drum, no leakage was observed between the flange and the top plate in the drop test and the airtight test, but in the hydraulic test, leakage from the same place was observed. Therefore, in the case of the present embodiment, the manufacturing method had a great advantage as compared with the conventional method, but in terms of the performance of the drum, leakage occurred in the water pressure test, so that the top plate and the ground plate of the drum were like drums. There is a limitation that it cannot be used in applications where extremely large internal pressure is applied such as swelling. Further, in the dipping test, a light yellow coloring was observed in gasoline, toluene and butyl acetate dipping, and a yellow coloring was observed in methylene chloride dipping, so that there was a limitation that a solvent having a strong dissolving power cannot be filled.

Example 9 A flange gasket having the composition shown in Example No. 9 in Table 1 was prepared. The type of this gasket is NBR. This gasket stretches 100
%, The tensile stress, the tensile strength, and the elongation in Example 1
Although the value was larger than that of the EPDM-based gasket shown in Example 8, the compression set was as large as 22.5%. Next, this gasket was attached to the flange to manufacture an inner coating drum in the process of the present invention shown in FIG.
As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. On the other hand, in the performance test of this drum, wetting was observed between the flange and the top plate in all of the water pressure test, the drop test and the airtight test. Therefore, in the case of the present example, the manufacturing method had a great advantage as compared with the conventional method, but since leakage occurred in the hydraulic test, the drop test and the airtight test of the drum, it was high when a large internal pressure was applied. There is a limitation that it cannot be used in the case where it may fall from a place and in applications where a high degree of airtightness is required. The gasket removed from the flange had a large crescent shape when it was permanently deformed at the location compressed by the top plate. Further, in the immersion test, no coloring was observed in gasoline immersion, but yellow coloring was observed in toluene and butyl acetic acid immersion, and deep yellow coloring was observed in methylene chloride immersion, so the dissolving power excluding gasoline was There was also a restriction that strong chemicals could not be filled.

Example 10 A flange gasket having the composition shown in Example No. 10 in Table 1 was prepared. The type of this gasket is fluororubber. Both the tensile stress and tensile strength at 100% elongation of this gasket were generally lower than those of the EPDM-based gaskets shown in Examples 1 to 8, and the compression set was also large. Next, this gasket was attached to the flange to manufacture an inner coating drum in the process of the present invention shown in FIG. As described in detail in Example 1, this manufacturing method has great advantages in productivity, capital investment, personnel, etc., as compared with the conventional method. On the other hand, in the performance test of this drum, leakage was observed between the flange and the top plate in all of the water pressure test, the drop test, and the airtight test. Therefore, in the case of the present example, the manufacturing method had a great advantage as compared with the conventional method, but since leakage occurred in the hydraulic test, the drop test and the airtight test of the drum, it was high when a large internal pressure was applied. There is a limitation that it cannot be used in the case where it may fall from a place and in applications where a high degree of airtightness is required. The gasket removed from the flange had a large crescent shape when it was permanently deformed at the location compressed by the top plate.

Although a gasket made of fluororubber is expensive, it has been said that it is excellent in heat resistance. However, when a production test was actually conducted on an inner coating drum, the permanent deformation of the gasket was large as described above. It was found that leakage occurred in drum performance tests such as the water pressure test. On the other hand, it is clear that the EPDM gasket has the same price as the conventional general-purpose NBR, but has good durability against the high temperature during baking after the inner surface coating. Became. In the drum performance test, leaks tend to occur in the water pressure test because the internal pressure of the drum rises and the top plate bulges like a drum, and wrinkles occur on the top plate around the mouthpiece, causing a gap between the top plate and the flange. Is easy to open. In addition, in the immersion test, coloring was not seen with the four types of chemicals,
It showed good solvent resistance.

(Comparative Example 1) An EPDM-based gasket having the same composition as that of Example No. 1 in Table 1 was attached to the flange, and an inner surface coating drum was manufactured by the conventional process shown in FIG. In this manufacturing process, since the manufacturing process is different from that of a normal drum without internal coating, the process control is complicated and the productivity is significantly inferior to the manufacturing process according to the present invention. Further, after the inner surface coating, another flange press-fitting press was required, and it was necessary to increase the number of workers for the work. Further, it was necessary to coat the flange inner surface of the drum in a separate process. In the performance test of this drum, no leakage was observed between the flange of the mouthpiece and the top plate in the water pressure test, the drop test, and the airtight test, and the gasket removed from the flange was slightly deformed.

(Comparative Example 2) A NBR type gasket having the same composition as that of Example No. 9 in Table 1 was attached to the flange and
An inner coating drum was manufactured by the conventional method shown in FIG. As described in detail in Comparative Example 1, this manufacturing method has various drawbacks as compared with the manufacturing method of the present invention. Since the flange was press-fitted onto the top plate after the inner surface was coated, the gasket of the flange was heated only by baking, which has a low temperature after the outer surface is coated.In the performance test of the drum, the water pressure test, the drop test,
In the airtight test, no leakage was observed between the flange and the top plate, and the gasket removed from the flange was slightly deformed. On the other hand, in the immersion test, coloring of the liquid was observed with chemicals other than gasoline. This coloring is due to the material of the NBR gasket.

[0034]

[Table 1]

The types of drums, gasket material test methods, drum manufacturing method details, and drum performance test methods in the above-mentioned Examples and Comparative Examples are as follows. (1) Kind of drum A class I M grade product (capacity 200 l, plate thickness 1.2 mm) among liquid steel drums specified in JIS Z 1601.
The inner surface is painted with epoxy phenolic paint.

(2) Gasket material test method A material test was conducted by the following method. (A) Tensile Test (Tensile Stress at 100% Elongation, Tensile Strength and Elongation) A vulcanized sheet having a thickness of 2 mm was made of the same material as the gasket, and the tensile test was performed according to JIS K 6301 (vulcanized rubber physical test method). Performed, tensile strength, elongation and elongation 10
The tensile stress at 0% was measured. The dumbbell type No. 3 was used as the test piece. (B) Hardness test A vulcanized sheet having the same material as the gasket and having a thickness of 12 mm was prepared, and JIS K 6301 (vulcanized rubber physical test method) was used.
According to the above, the hardness was measured using a spring type hardness tester type A. (C) Compression set test Using a vulcanized test piece prepared from the same material as the gasket, a compression set test was conducted according to JIS K 6301 (vulcanized rubber physical test method). However, the size of the test piece was 5 mm width × 30 mm length × 2 mm thickness, the compression temperature was 230 ° C., the compression time was 30 minutes, the compression rate was 30%, and the strain was measured 30 minutes after the load was released.

(3) Details of Drum Manufacturing Method A drum was manufactured by the process of the present invention shown in FIG. That is, as in the case of a normal drum without an inner surface coating, the flange with a gasket was press-fitted and fixed to the top plate and then the inner surface was coated, and then the body and the main plate were wound around and the outer surface was coated. Then, an epoxy phenolic paint was used for the inner surface coating, and baking was performed by passing it through a tunnel-shaped hot air oven. The temperature in the tunnel hot air oven is low at the inlet and the outlet and high near the outlet in the central part, so the degree of curing of the coating film is 1
The temperature in the hot-air stove was adjusted so that it would be the same as when it was baked for 5 minutes.

The outer surface was coated with a melamine alkyd paint and baked by passing through a tunnel-shaped hot air oven. This baking is equivalent to baking at 130 ° C. for 20 minutes in a closed electric furnace. With this drum manufacturing method, the inner surface coating can be manufactured in exactly the same process as a normal drum without inner surface coating, and the conventional drum with inner surface coating and the conventional drum without inner surface coating can be manufactured in the top plate processing step. There is an advantage that there is no need to divide.
In addition, there is a great advantage that the flange press-fitting equipment and the personnel therefor are not required after the inner surface coating. Further, there is also a feature that it is not necessary to previously coat the inner surface side of the flange of the drum in a separate process.

(4) Method of drum performance test (a) Water pressure test, drop test and airtight test According to JIS Z 1601 (steel drum for liquid)
A water pressure test, a drop test and an air tightness test were performed. The internal pressure during the water pressure test was 0.5 MPa, the drop test was a diagonal drop at a drop height of 2.4 m, and the airtight test was an internal pressure of 0.4 MPa, which were stricter than JIS standards. Separately from the above test, the flange was removed from the mouthpiece part of the drum, the gasket was taken out, and its deformation was visually observed.

(B) Immersion test Approximately 100 ml of the test solution was placed in a glass bottle having a capacity of 450 ml, one gasket for a large stopper flange was completely immersed in the test solution, and the glass bottle was tightly capped at room temperature (at 20 ° C.). The test liquid was kept for 10 days in the air conditioner), and then the test liquid was visually observed for coloration. The four chemicals tested were gasoline, toluene, butyl acetate, and methylene chloride. The color tone of these chemicals before dipping is light pink for gasoline, and the others are colorless and transparent.

[0041]

As described above, in the method of manufacturing an inner surface coating drum according to the present invention, the flange press-fitting process to the top plate is performed in the same process as a normal drum without inner surface coating, and the flange and the top plate are simultaneously formed on the inner surface. Since it is painted, the productivity is greatly improved. It also has the great advantage that there is no need for double investment in the press-fitting press and double allocation of press-fitting work personnel. Further, there is no need to pre-coat the flange inner surface side of the drum in a separate process. Furthermore, EPDM was selected as the material of the gasket, the vulcanization method thereof was specified, and the upper limit of the amount of the component eluted in the solvent such as the softening agent was regulated, which was a drawback of the conventional flange gasket. It was also possible to solve the problem of coloring the contents of the drum when a highly soluble chemical was filled in the drum. In the examples, only the sealed steel drum having a capacity of 200 l was taken up, but the effect of the present invention is exhibited in the same manner in the open drum and the drums having other capacities, and other inner surfaces such as pail cans are coated. It has an extremely excellent effect that can be applied to a metal container.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of an inner coating drum according to the present invention,

FIG. 2 is a diagram showing a manufacturing process of a conventional inner coating drum,

FIG. 3 is a diagram showing a manufacturing process of a drum without inner surface coating;

FIG. 4 is a conceptual diagram of a sealed drum showing a general shape,

FIG. 5 is a conceptual diagram of a drum mouth part showing a general shape.

[Explanation of symbols]

 1 Top plate 2 Base plate 3 Body 4 Large plug 5 Small plug 6 Flange 7 Plug 8 Flange gasket 9 Plug gasket

Claims (6)

[Claims] 1. A method of manufacturing an inner surface coating drum, which comprises press-fitting a flange of a mouthpiece, to which a gasket is previously attached, onto a top plate, and then coating the baking-type paint on the inner surface. 2. Tensile stress at 100% elongation is 5 to 1
The method for producing an inner coating drum according to claim 1, wherein a gasket having physical properties of 2 MPa and a tensile strength of 14 to 30 MPa is attached to the flange. 3. The method for manufacturing an inner coating drum according to claim 2, wherein a gasket whose main material is EPDM is attached to the flange. 4. The inner coating according to claim 3, wherein a gasket made of a material in which at least 70% by weight or more of EPDM before vulcanization has a Mooney viscosity of 25 ML1 + 4 (100 ° C.) or more is attached to the flange. Drum manufacturing method. 5. The method for manufacturing an inner coating drum according to claim 3, wherein a gasket prepared by vulcanizing EPDM with a mixture of peroxide and sulfur is attached to the flange. 6. The flange is fitted with a gasket made of a material in which the total amount of the softening agent, the plasticizer, the tackifier and the lubricant is 8% by weight or less of the entire gasket. A method for manufacturing an inner surface coating drum as described.