JPH03256742A - Manufacture of resin laminate coated metal sheet - Google Patents

Abstract

PURPOSE:To upgrade the quality of a product by measuring the refractive index of a laminated thermoplastic resin film on a metal sheet in a non-contact manner, adjusting the calorie to be transmitted to the thermoplastic resin at the time of laminating and controlling the crystallized state of the thermoplastic resin film. CONSTITUTION:A 25mu saturated polyester resin film is fixed by pressure in the range of approximately 300m/min. line speed on a heated sheet of 0.265mm thickness by the electric resistance heating method, and then a laminate steel sheets are continuously manufactured by the method of quenching and drying under water. In that case, the refractive index of the saturated polyester resin film is measured on the position where quenching and drying were carried out by utilizing a device in which a spectral reflection measuring device and an infrared ray film thickness meter are combinedly used in the six points in the width direction of the laminate steel sheet, and the current of electric resistance heating and the sheet feeding speed are controlled so that respective birefringence degree of the saturated polyester resin film comes to, and the refractive index in the thickness direction at respective measuring points comes close to 1.563+ or -0.003, and the laminate sheet is manufactured.

Description

Detailed Description of the Invention [Industrial Field of Application] This invention relates to a resin laminate coating that online controls the crystalline state of a thermoplastic resin film within a predetermined range on a thermoplastic resin laminate metal plate manufactured at high speed. This invention relates to a method for manufacturing a metal plate.

[Prior Art] In recent years, resin-laminated metal plates in which resin is bonded onto metal plates have been used for container materials, home appliances, building materials, and the like.

There are two methods for laminating resin on a metal plate: one method is to apply an adhesive and adhere the resin film, the other is the thermal bonding method where part or all of the resin film is heated above its melting point and bonded, and the resin is extruded from a T-tie. There is a T-die method in which the material is directly laminated onto a metal plate.

When a thermoplastic resin is laminated onto a metal plate, the processability of the resin film has a large relationship with the crystalline state of the resin film.

The crystalline state of thermoplastic resin is 8.0 structure consisting of oriented crystals and amorphous, R consisting of non-oriented crystal and amorphous,
It can be roughly divided into three crystalline states: 0 structure, N structure consisting only of amorphous structure, and O structure structure. A resin with an 8.0 structure changes to an R,0 structure when the oriented crystals are destroyed by heating. In addition, when the N, O structure of highly crystalline resin is heated, cold crystals are generated,
Changes to R,0 structure. Any structural changes are a function of temperature and time. That is, it is known that even if a resin is heated to the same temperature, if the time is long, a structural change will occur, but if the time is short, no structural change will occur.

Among the crystal structures, the R,0 structure has the worst workability.

In particular, in the case of polyester, cracks may occur in the resin, or in extreme cases, the resin may become powdery. Therefore, depending on the use, processing, or heating process of the resin-laminated steel sheet, it may be necessary to differentiate the crystal structure of the thermoplastic resin film into an 8.0 structure or an N,0 structure.

For example, a tin plate laminated with polyester is
When performing extremely severe ironing processing such as I-forming, the crystalline state of the resin film must be an N,O structure. Even if the crystalline state of the resin film is 8.0 structure as well as 8.0 structure, the resin film will have defects. This is because the resin film is violently stretched during ironing, and the resin film after ironing changes from an N,O structure to an 8.0 structure. In the case of a resin film having an 8,0 structure that has already been stretched, the film is stretched beyond the limit of the resin, so that the film cannot follow the processing and film defects occur. Furthermore, in severe cases, not only the film is defective, but also the tin plate as a base material may be broken, making it impossible to process.

In addition, when a highly crystalline thermoplastic resin laminated metal plate undergoes a heating process such as painting baking,
Structure is desirable. If the crystal structure of the resin film is 8.0, cold crystals will form and processability will be lost thereafter. In particular, when thermoplastic polyester is used, it may turn into powder and not form a film. If the crystal structure of the thermoplastic resin film is 8.0, the temperature at which the oriented crystals are destroyed is higher than the temperature at which cold crystals are formed, and the temperature is higher than the temperature at which the oriented crystals are formed.
．． Since the zero structure is stable at considerably high temperatures,
8.0 structure is desirable.

In order to manufacture a laminated metal plate in which the crystal structure of the thermoplastic resin film is 8.0, it is necessary to laminate the stretched and oriented film at a temperature below which the oriented crystals are destroyed. Therefore, lamination is performed by using an adhesive or adhesive layer or by melting only a portion of the stretched and oriented film. If the temperature during lamination is too high, the oriented crystals will be destroyed and an R,O structure will result, so temperature control during lamination is important.

The N,O structure is created by rapidly cooling the resin in a molten state. If the molten state is incomplete, that is, if the heating is insufficient and crystals remain, or if the cooling is insufficient, the R,O structure will be formed. Furthermore, if the temperature of the resin is increased too much, the resin will decompose, so temperature control during lamination is also important in this case as well.

Furthermore, in the lamination process, the N and O structure of the thermoplastic resin film is transferred to the laminate film even when the laminated metal plate is made into an 8.0 structure, or when it goes through a heating process such as painting and baking. It is necessary to control the crystalline state of the resin film by adjusting the amount of heat applied.

Therefore, when manufacturing a laminated metal plate made of silent plastic resin, it may be necessary to create different crystal structures for the resin film, and also when the laminated metal plate is passed through a heating process. There has been a need to control the crystalline state of resin films by adjusting the amount of heat transferred to the laminate film. Therefore, in order to supply a thermoplastic resin laminated metal plate with a stable crystalline state at a low cost, it has become important to control the crystalline state of a thermoplastic resin film online.

[Problem to be Solved by the Invention 11J] As described above, the crystalline state of the thermoplastic resin coating of the thermoplastic resin laminated metal plate may have a large effect on the workability of the laminated metal plate.

However, there is no method for controlling the crystalline state by online measuring data regarding the crystalline state of a thermoplastic resin film laminated on a metal plate that is passed at high speed. For this reason, methods have been adopted to control the crystalline state of the thermoplastic resin film by adjusting the heating furnace temperature, metal plate temperature, or plate passing speed using empirical or calculation methods.
By measuring the crystalline state of the thermoplastic resin film off-line, it has been confirmed that the thermoplastic resin film has been manufactured in a predetermined crystalline state. Off-line measurement takes time, and if the crystalline state of the thermoplastic resin film is out of a predetermined range, a large number of defective products will be manufactured, increasing manufacturing costs.

Therefore, in order to supply thermoplastic resin laminated steel sheets with stable quality at low cost, it has become important to control the crystalline state of the thermoplastic resin film online.

The present invention measures the refractive index of a thermoplastic resin film non-destructively online in a continuous production line for thermoplastic resin laminated metal plates during high-speed sheet passing, and transmits the refractive index to the thermoplastic resin film based on the results. By adjusting the amount of heat,
The aim is to provide a thermoplastic resin laminated metal plate with stable quality by controlling the crystalline state of the thermoplastic resin film online.

[Means for Solving the Problem] The present invention measures the refractive index of a thermoplastic resin film laminated on a metal plate online in a non-contact manner, and measures the refractive index transmitted to the thermoplastic resin during lamination based on the result. This method is characterized by controlling the crystalline state of the thermoplastic resin film online by adjusting the amount of heat used.

Although the present invention is effective for thermoplastic resin-coated metal plates, it is particularly desirable that it be adopted as a method for manufacturing saturated polyester resin-coated metal plates whose workability is greatly affected by the crystalline state of the resin film.

In the non-contact, non-destructive method for measuring the refractive index of a thermoplastic resin film in the present invention, it is desirable to use a device that uses a spectral reflectance measuring device and an infrared film thickness meter in combination. According to this device, it is possible to optically measure the refractive index of the resin film in the thickness direction in a non-contact and non-destructive manner even during high-speed sheet passing. In principle,
The difference in optical path length is determined using a spectral reflectance measuring device, and the refractive index in each direction of the resin is calculated from the film thickness determined using an infrared film thickness meter.

It is well known that S fat having oriented crystals has birefringence. Therefore, by calculating the degree of birefringence by measuring the refractive index in each direction using the above-mentioned refractive index measuring device, it is possible to know the degree of orientation of the 8.0 structure of the resin film.

When birefringence is not exhibited, the structure of the resin film is either an R,0 structure or an N,0 structure, with the N,0 structure exhibiting a smaller refractive index.

In addition, even if we focus only on the refractive index in the thickness direction of the thermoplastic resin film, the highest value is shown when the film has an 8.0 structure in the crystalline state, and the values decrease in the order of R,0 structure and N,0 structure. becomes.

However, the degree of birefringence and the refractive index value in each direction of the film in each crystalline state differ depending on the type of thermoplastic resin. For this reason, we measured the birefringence and refractive index in each direction of the thermoplastic resin coating in each crystalline state of a laminated metal plate whose crystalline state is known in advance, and then measured it during actual manufacturing. By comparing the values, it becomes possible to recognize the crystalline state of the resin film.

The amount of heat transferred to the resin film can be adjusted by adjusting the output of the heat source, the sheet passing speed, etc. alone or in combination. For example, when heating a metal plate by electric resistance heating and laminating resin on it, the amount of heat transferred to the resin film can be adjusted by adjusting the output of the electric resistance heating alone or in combination with the sheet threading speed. do.

Therefore, by using the method of the present invention, for example, B,
When manufacturing a laminated metal plate with a thermoplastic resin film having an O structure, N When manufacturing a laminated metal plate with a thermoplastic resin film having a zero structure, the amount of heat transferred to the resin film is adjusted so that birefringence does not occur and the refractive index of the film is minimized. , it is possible to control the crystalline state of the thermoplastic resin film.

[Function] As detailed above, the refractive index of the thermoplastic resin film on the laminated metal plate is measured online during high-speed threading in a continuous production line for thermoplastic resin laminated metal plates, and the lamination process is performed based on the results. By adjusting the amount of heat transferred to the thermoplastic resin during heating, it becomes possible to control the crystalline state of the thermoplastic resin film. Furthermore, it is also possible to apply the present invention to the case where a thermoplastic resin laminated metal plate is threaded through a threading line that involves heating, such as a coil coating line.

Therefore, it is possible to manufacture a thermoplastic laminated metal plate in which the crystalline state of the thermoplastic resin film is stable at a low cost.

[Example 1] A 25μ saturated polyester resin film is pressed onto a 0.265mm thick tin plate heated by electric resistance heating at a line speed of about 300m/min, and then rapidly cooled in water and dried. In a line that continuously manufactures laminated steel sheets by this method, the refractive index of the saturated polyester resin film is measured in the width direction of the laminated steel sheet by using a device that combines a spectral reflectance measurement device and an infrared film thickness meter at the position after rapid cooling and drying. The current and threading speed of electrical resistance heating were controlled so that each birefringence of the saturated polyester resin film was 0 and the refractive index in the thickness direction was 1.563 ± 0.003 at each measurement point. , produced laminated steel sheets.

We measured the X-ray diffraction and infrared spectra of the saturated polyester resin coating on the manufactured laminated steel sheets, and found that the laminated steel sheets had a complete N,0 structure in the width and length directions, and that stable manufacturing was possible. confirmed.

Example 2 Molten polypropylene resin was pressed from a T-die onto a 0.3 mm copper plate that had been preheated by high-frequency heating during sheet passing at a line speed of about 150 m/min, and a film thickness of 40 μm was obtained.
In the line for forming the laminate film, after the film cooling process, the refractive index in the thickness direction of the polypropylene resin was measured at three points in the width direction using a device that combines a spectral reflectance measuring device and an infrared film thickness meter. The output of high-frequency heating, the temperature during extrusion of the polypropylene resin, and the sheet passing speed were adjusted so that the refractive index of the polypropylene resin was 1.450±0.005.

We measured the X-ray diffraction and infrared spectra of the polypropylene resin coating on the manufactured laminated copper plate, and found that the laminated copper plate had a complete N,0 structure in the width and length directions, and that stable production was possible. confirmed.

Example 3 In coil coating with a flame heating furnace, a 30 μ biaxially stretched saturated polyester film was laminated on one side of a 0.2 mm aluminum plate with an adhesive at a line speed of about 120 m/min. Paint was applied to the opposite side using a roll coater and baked. At the exit of the heating furnace, the refractive index of the saturated polyester film was measured at five points in the width direction by using a device that combined a spectroscopic-reflection measuring device and an infrared film thickness meter,
The line speed or heating furnace temperature was adjusted so that Δy of the birefringence of the saturated polyester film was 0.2 or more -E, and the coating was baked.

We measured the X-ray diffraction and infrared spectra of the saturated polyester resin film on the painted laminated aluminum plate.
8. Across the width direction and longitudinal direction of the laminated aluminum plate.
It was confirmed that the zero structure remained completely and that stable production was possible.

[Effects of the Invention] As described above, according to the present invention, the refractive index of a thermoplastic resin film on a laminated metal plate can be measured online during high-speed threading in a continuous production line for thermoplastic resin laminated metal plates. By adjusting the amount of heat transferred to the thermoplastic resin based on the results, it is possible to control the crystalline state of the thermoplastic resin film, resulting in a thermoplastic laminated metal plate with a stable crystalline state of the thermoplastic resin film. can be manufactured at low cost.

Claims (1)

[Claims] 1. In a continuous production line for thermoplastic resin laminated metal plates, the refractive index of the thermoplastic resin film on the laminated metal plate was measured online non-destructively, and based on the results, the thermoplastic A method for producing a resin laminate-coated metal plate, characterized in that the crystalline state of a thermoplastic resin film is controlled online by adjusting the amount of heat transferred to the resin film. 2. The method for manufacturing a resin laminate-coated metal plate according to claim 1, wherein the thermoplastic resin is a saturated polyester resin. 3. The method for manufacturing a resin laminate-coated metal plate according to claim 1 or 2, characterized in that the refractive index measurement method uses a device that combines a spectral reflectance measuring device and an infrared film thickness meter.