JPH0365785B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for trimming edges (hereinafter simply referred to as "ears") of coating resin that protrude from a base material during extrusion coating of a thermoplastic resin. Conventional techniques Conventionally known side trimming methods include a method in which after extrusion coating, the thermoplastic resin is cooled and solidified with a cooling roll, and then trimmed by applying cutters to both sides (Fig. 2), high-pressure water,
Methods such as side trimming using laser beams have been used. Problems to be Solved by the Invention In the former method, there is no problem when the base material is paper, plastic, aluminum foil, etc., but when the base material is a metal plate, the tension on the ears may be Because it cannot be cut, it is unstable and cannot be trimmed, and the cutter blade comes into contact with the metal plate and breaks, resulting in a short lifespan. The latter method has problems such as high equipment costs. The present invention has been made to solve these conventional problems, and makes it possible to easily perform side trimming of the ears. Means for Solving the Problems The side trimming method of the present invention continuously trims only the edges of the thermoplastic resin by using the cooling roll and nip roll and the edge of the metal plate without using tools such as cutters. This is a method of cutting.
That is, the present invention extrudes a thermoplastic resin melt-kneaded in an extruder into a film form from a T-die,
In a method of manufacturing a surface-treated metal plate by directly and continuously coating a preheated metal substrate in a molten state, the metal substrate is coated with a cooling roll at the pressure bonding point during extrusion coating of a thermoplastic resin. A method for manufacturing a surface-treated metal sheet, which comprises: cooling the extruded and coated thermoplastic resin directly with a nip roll, and trimming edges of the coating resin that protrude from the metal substrate. It is. Function Next, the present invention will be specifically explained. In FIG. 1, 1 is a metal plate, 2 is a die, 3 is a thermoplastic resin in a molten state, 4 is a cooling roll, and 5 is a nip roll. The surface material of Nitzprol 5 is heat resistant as it comes into contact with high temperature resin.
It is also necessary to use a material with excellent peelability, such as silicone rubber, fluorine rubber, etc. The thermoplastic resin 3 in a molten state extruded from the die 2 is pressed onto the metal plate 1 by a cooling roll 4 and a nip roll 5. In the trimming method of the present invention, the edges 9 of the coating resin protruding from the metal plate during extrusion trimming are attached to the cooling roll 4 so as to obtain an appropriate adhesive force, and the edges are stretched and cut. . FIG. 3 is an explanatory view showing the principle in which the coated metal plate bites into the surface of the nip roll and the selvage is trimmed by being rolled down in the AA′ cross section of FIG. 1. The ears attached to the cooling roll are peeled off from the cooling roll using a doctor blade, scraper roll, etc., and then removed using a suction machine. Alternatively, it can be collected by winding up the band-shaped ears or by other means. At this time, the rubber hardness of Nipprol is preferably 50 degrees or more; lower hardness is not preferred because the ears cannot be cut. Further, the recommended pressure for crimping is in the range of 20 to 50 kg/cm. If it is less than 20 kg/cm, it will be difficult to trim, and if it exceeds 50 kg/cm, there will be no change in the trimming condition and the life of the roll will only be shortened, which is not preferable. By using this method, all the trimmed ears can be reused and there is little equipment cost. It has many advantages such as easy work and no need for adjustment even if the width of the base material changes. The trimming method of the present invention can be used for:
The base material is a cold-rolled steel plate, galvanized steel plate, aluminium-plated steel plate, aluminum plate, stainless steel plate, etc. with a thickness of 0.2 to 2 mm. The thickness of the resin to be laminated varies depending on the rubber hardness and crimping pressure, but is the maximum. and up to the same thickness as the base material. If the thickness is greater than this, good trimming cannot be expected. As the resin to be laminated, it is possible to use any resin that can be extruded with a T-die, such as polyethylene, polypropylene, polycarbonate, nylon, polyurethane, and fluorine. It can also be used for lamination of two or more layers, and there is no problem with the same resin, but when laminating different types of resin, the difference in melting point of each resin can be used.
Although temperatures up to 60°C are possible, temperatures below 40°C are preferred from the viewpoint of work stability. If there is a temperature difference larger than this, the appropriate range of resin temperature during trimming will be exceeded, so when extruding two layers at the same time, work under high melting point conditions, especially if the film thickness of low melting point resin is thick. This is because good trimming cannot be expected. When using the method of the present invention, there are two points that are particularly important to adjust during operation: the temperature of the cooling roll and the temperature of the resin at the pressing point (during trimming). The temperature of the cooling roll is controlled in order to attach the ears to the cooling roll with an appropriate adhesive force; if the temperature is too low, the ears will not stick and trimming will be impossible, and if the temperature is too high, the ears that have been trimmed will not be cooled. It becomes difficult to peel off from the roll. The appropriate temperature range for the cooling roll varies depending on the type of resin, and is preferably from the melting point to -70°C. For example, a temperature range of 50 to 120°C is recommended for polyethylene, and a range of 100 to 170°C for polypropylene. The temperature of the resin at the crimping point is to stretch and cut the selvedge, and a melting point of ±30°C is ideal. At temperature, the ears are in a molten state, they only stretch and are impossible to cut. The effects will be explained below based on examples. Example Hot-dip galvanized steel sheets of various thicknesses shown in Table 1 were used as metal substrates, and after preheating (150°C),
On top of this, the laminated resin shown in Table 1 was extruded from a two-layer T-die to the thickness shown in Table 1. At the extrusion point, the metal plate was cooled from the back side with a cooling roll, while the coated resin surface was pressed down with a Nippro roll (surface material is silicone rubber with a hardness of 75° and a thickness of 20 mm) to extrude from the metal substrate. Coating resin ears trimmed. Table 1 shows cooling roll temperature, pressure bonding point resin temperature,
Adhesion strength and trimming condition are shown. The melting point was measured using the DSC method. Adhesive strength and trimming condition were evaluated based on the following criteria. (1) Evaluation of adhesive strength ○...Peel strength 1.0Kg/cm or more, good. △...Peel strength: 0.2 to 1.0 Kg/cm, adhesive strength is unstable. ×...Peel strength less than 0.2Kg/cm, no adhesion. (2) Evaluation of trimming condition ○...Good. ○～△...Slight edges remain on the edges of the laminated resin. △...Some ears remain on the edges of the laminated resin. △～×: Significant ears remain on the edges of the laminated resin. ×……Trimming is not possible.

【table】

【table】

[Table] Comparative Examples Similarly, comparative examples are shown in Table 2. Effects of the Invention According to the method of the present invention, good trimming can be performed, all trimmed ears can be reused, and the operation is easy with almost no equipment cost. There are many advantages such as no need for adjustment even if the width of the base material changes.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the process of the present invention, FIG. 2 is an explanatory diagram of the conventional method, and FIG. 3 is a schematic explanatory diagram of the end face of the AA' cut portion in FIG. 1. 1...Metal plate, 2...Dice, 3...Resin, 4
...Cooling roll, 5...Nippro roll, 6,7...
... Roll, 8 ... Laminated resin, 9 ... Trimmed ears, 10 ... Side trimming.

Claims (1)

[Claims] 1. A thermoplastic resin melt-kneaded in an extruder is
In the method of manufacturing surface-treated metal plates by extruding the film from a die and directly and continuously coating it in a molten state onto a preheated metal substrate, the pressure bonding point is In this process, the metal substrate is directly cooled by a cooling roll, and the extruded and coated thermoplastic resin is compressed with a Nippro roll at a pressure of 20 to 50 kg/kg.
Surface treatment characterized by reducing the edge of the coating resin in a range of cm, adhering the edge of the coating resin to a cooling roll, stretching the edge, and trimming the edge of the coating resin protruding from the metal substrate using the edge of the metal substrate. Method of manufacturing metal plates. 2 The surface temperature of the cooling roll is below the melting point of the thermoplastic resin and at least 70°C lower than the melting point of the thermoplastic resin, and the temperature of the thermoplastic resin at the compression point is 30°C below the melting point of the thermoplastic resin. 2. The method for producing a surface-treated metal plate according to claim 1, wherein the temperature is below a high temperature and above a temperature that is 30° C. lower than the melting point of the thermoplastic resin. 3. The method for manufacturing a surface-treated metal sheet according to claim 1 or 2, wherein two types of thermoplastic resins are extruded and laminated in two layers, and the difference in melting point between the two resins is within 40°C.