JPS6144065B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite plate, and more particularly, to a method for manufacturing a composite plate in which metal sheets are laminated on both sides of a thermoplastic synthetic resin sheet.

The above composite board is, for example, US Pat.
It has been known for a long time from No. 3382136, and is used for various purposes as an excellent composite material that has the characteristics of both metal and thermoplastic synthetic resin (hereinafter simply referred to as "synthetic resin").

Therefore, such a composite plate is basically manufactured continuously by a method including the following steps as disclosed in, for example, US Pat. No. 3,616,019.

That is, the method consists of (a) heating two metal sheets stretched at a constant tension, and (b) heating a preheated metal sheet and a synthetic resin sheet in a molten state, with a synthetic resin sheet between the metal sheets. This method includes a bonding step of obtaining a composite plate by supplying the composite plate between heated and pressure rollers, and (c) a cooling step of cooling the obtained composite plate.

However, one problem with the above method is that wrinkles and waves occur on the metal sheet surface of the composite plate. Such problems with the metal sheet surface impair the aesthetic appearance when the composite board is used, for example, as a material for furniture. The occurrence of wrinkles and waves is more pronounced as the metal sheet becomes thinner and the synthetic resin sheet becomes thicker.

Thus, the problem of wrinkles on the metal sheet surface is being solved by certain methods. The same applies to so-called transverse waves generated on the metal sheet surface in a direction perpendicular to the direction in which the composite plate is stretched.

However, no effective solution has yet been found for the so-called longitudinal waves that occur on the metal sheet surface in the direction of expansion of the composite plate.

An object of the present invention is to provide a composite plate having no longitudinal waves as described above on the metal sheet surface, and this object can be easily achieved according to the following invention.

That is, the present invention is a method for manufacturing a composite plate in which metal sheets are laminated on both sides of a thermoplastic synthetic resin sheet, which comprises the steps of: (a) preheating two metal sheets stretched at a constant tension; b) A bonding process for obtaining a composite plate by supplying a preheated metal sheet and a molten synthetic resin sheet between heated pressure rollers so that the synthetic resin sheet is interposed between the metal sheets; A deformation step in which the composite plate is passed between a plurality of rollers arranged in a staggered manner so as to impart deformation to the composite plate within a degree equivalent to its bending elastic limit; (d) Composition between the rollers in the deformation step; A method for manufacturing a composite plate, comprising: a cooling step of cooling the composite plate so that the temperature of the resin falls below its softening point.

Hereinafter, the method of the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 is a side view schematically showing an example of the method of the present invention, and FIG. 2 is a side view schematically showing the arrangement of rollers in the deformation step.

First, metal sheet 1 used in the method of the present invention,
1' and the synthetic resin sheet 2 will be explained.

The metal sheets 1 and 1' include aluminum,
Sheets of steel, iron, copper, tin or nickel or alloys thereof are used. metal sheet 1,1'
The thickness is less than 0.5mm, usually 0.05~0.5mm
are used.

Furthermore, the synthetic resin sheet 2 is not particularly limited as long as it can be used for normal extrusion molding.
For example, polyethylene, polypropylene, polybutene, polyvinyl chloride, polystyrene, polyamide, polycarbonate, etc. are used, but from the viewpoint of extrusion moldability, it is preferable to use polyolefin-based synthetic resins such as polyethylene, polypropylene, polybutene, etc.

The thickness of the synthetic resin sheet 2 is not particularly limited;
It is appropriately selected depending on the desired thickness of the laminate, but is generally 1 to 10 mm.

The metal sheets 1, 1' are pulled out from the uncoilers 3, 3' by take-off rollers 4, 4' in a stretched state with a constant tension. The tension applied to the metal sheets 1, 1' can be changed arbitrarily by adjusting the braking force of the uncoilers 3, 3', and is usually between 0.2 and 1'.
Controlled to a constant value within the range of 1.5Kg/ ^mm2 .

The stretched metal sheets 1, 1' are first passed through a surface treatment step 5, 5', where necessary surface treatments such as degreasing, washing, drying, etc. are performed according to conventionally known methods.

The metal sheets 1, 1' are then subjected to a preheating step 6,
Preheated through 6'. The preheating temperature is set to a temperature near the temperature of the heating pressure bonding rollers 8, 8', which will be described later. The preheated metal sheets 1, 1' are supplied together with the molten synthetic resin sheet 2 extruded from the extruder 7 between heated pressure rollers 8, 8' in the bonding process, and bonding is performed.

If the temperature of the synthetic resin sheet 2 is too low, it may not adhere well to the metal sheet, so it is necessary to determine the temperature of the synthetic resin sheet 2 in consideration of the wettability between the resin used and the metal. When using a polyolefin synthetic resin, it is best to select a temperature within the range of approximately 180 to 240°C. In addition, heated pressure bonding rollers 8, 8'
The temperature is the type of synthetic resin, metal sheet 1, 1'
It cannot be determined definitively because it depends on the drawing speed of the roller, but when using polyolefin-based synthetic resin, the surface temperature of the roller
The temperature is about 180-230℃.

The composite plate sent out from between the pressure rollers 8 and 8' is heated and aged in a heating step 9, if necessary. This heat aging is particularly significant when an adhesive is used in conjunction with the bonding of the metal sheet and the synthetic resin sheet. In other words, heat aging mainly
This has the effect of ripening the chemical reaction of the adhesive.

The gist of the method of the present invention is to introduce the composite plate obtained through the bonding process into a special deformation process.

The deformation process consists of a plurality of rollers 11, 11'... arranged in a staggered manner. These roller groups preferably have a diameter in the range of 50 to 200 m/m. Generally speaking, each roller has a distance between their axes relative to the roller diameter d.
It is arranged so that it is in the range of 0.5 to 2d. Also,
As shown in FIG. 2, the rollers are arranged so as to slightly overlap each other in the vertical direction and to impart a deformation of less than the bending elastic limit to the composite plate passing between the rollers. Such a slight overlap is determined by a method in which the cold bending elastic limit of the composite plate to be actually manufactured is determined in advance by varying the degree of overlap. For example, thickness 1.6m/
In the case of a composite board in which aluminum sheets with a thickness of 0.2 m/m are laminated on both sides of a polyethylene sheet with a thickness of
You can choose from a range of about 10m/m.

In the method of the present invention, it is important to cool the composite plate between the rollers 11, 11', . . . in the deformation step so that the temperature of the synthetic resin falls below its softening point.

The composite plate is cooled by roller 1 at the beginning of the deformation process.
The cooling process is performed by a cooling chamber 10 provided in front of the cooling chamber 10 and a blower 12 placed opposite the roller group. The cooling chamber 10 is for pre-cooling the entire composite plate passing through it, and this cooling is performed by air introduced into the cooling chamber 10 by a blower (not shown). be exposed. Further, the cold air blower 12 is used to ensure that the temperature of the synthetic resin in the composite plate falls below its softening point between the rollers 11, 11'. An air distribution tube (not shown) is provided with a length spanning the width of the composite plate. Moreover, the roller 11,
11'... It is also possible to allow cooling water to flow through itself.

Actual temperature control in the cooling process is performed by determining in advance the temperature of the metal sheet surface when the temperature of the synthetic resin is below its softening point, and using this temperature as an index.

For example, in the case of an aluminum-low-density polyethylene composite plate with the specifications mentioned above, the surface temperature of the aluminum sheet should be approximately 100 to 110°C near the entrance roller of the deformation process, and approximately 80 to 90°C near the exit roller. By cooling, the conditions of the cooling step of the present invention can be satisfied.

The softening point of the synthetic resin is measured in accordance with ASTM-D155, and is approximately 99°C in the case of low density polyethylene.

According to the method of the present invention described above, it is possible to almost completely prevent the generation of longitudinal waves on the metal surface, which has been difficult to prevent in the past, and to produce a composite plate with a beautiful appearance.

The reason why the method of the present invention can prevent the generation of longitudinal waves on the metal surface is not necessarily clear, but in the conventional manufacturing method, the synthetic resin enters a solidified state while being under tension in the stretching direction, thereby causing so-called vertical waves. In contrast to the generation of waves, in the method of the present invention, when the synthetic resin enters a solidified state, it is thought that the applied tension is relaxed by undergoing forced bending deformation.

Next, the present invention will be explained in more detail with reference to Examples.

Example Using the apparatus shown in Figure 1, a 0.15 m/m thick sheet was coated on both sides of a 1.7 m/m thick low density polyethylene sheet.
A composite plate made of laminated aluminum sheets was manufactured continuously.

Polyethylene (softening point: about 99°C) blended with a commercially available adhesive was extruded from extruder 2 at a rate of 470 kg/hr into a sheet with a thickness of 1.7 m/m and a width of 1000 m/m. The temperature of the sheet was approximately 220°C.

An aluminum sheet having a thickness of 0.15 m/m was pulled out from the uncoilers 3, 3' by take-up rollers 4, 4'. The tension on the aluminum sheet is approximately
It was 0.8Kg/ ^mm2 .

Pass the aluminum sheet through surface treatment step 5,
Degreasing, washing with water, chemical conversion treatment, and drying treatment were performed according to conventionally known methods.

After the surface-treated aluminum sheet was preheated to about 200° C. through preheating steps 6 and 6', it was fed together with the polyethylene sheet extruded from extruder 2 between hot pressure rollers 8 and 8' to perform lamination. The temperature of the heated pressure roller was about 210°C.

The composite plate sent out from the heated pressure bonding roller was pre-cooled through the cooling chamber 10 until the temperature of the aluminum sheet surface reached about 105°C.

Roller 1 in the process of deforming the pre-cooled composite plate
1, 11'...... and was cooled by a cold air blower 12. The temperature of the aluminum sheet surface of the composite plate is approximately 105% at the entrance roller position.
The temperature was approximately 85°C at the exit roller.

The dimensions and arrangement of the rollers in the deformation process are as follows.

Number of rollers: 11 Diameter of rollers: 100 m/m Distance between roller axes: 65 m/m Overlap of rollers: 3 m/m For the composite plate manufactured in this way, the generation of longitudinal waves can be determined using a differential transformer. When measured using a test device, the graph shown in FIG. 3a was obtained.

For comparison, a composite board was manufactured in the same manner as above except that the roller group in the deformation process was removed, and the generation of longitudinal waves in the obtained belly plywood was measured, and the graph shown in Figure 3b was obtained. Obtained.

In principle, a longitudinal wave test device has a roller freely supported at one end of a variable spindle of a differential transformer, and a fixed roller is provided opposite to the roller, and a plate-shaped sample piece is passed between both rollers. This device records the vertical movement of a variable spindle that follows the unevenness of the sample surface.

In this example, a plate-shaped specimen cut to a predetermined size is passed between the rollers from its width direction (perpendicular to the direction of withdrawal of the production line) to create surface irregularities (i.e., in the direction of withdrawal of the production line). We measured the so-called longitudinal waves generated in the Therefore, Figures 3a and 3b show the surface condition observed from the direction in which the composite plate is pulled out. Note that in this figure, the vertical axis is enlarged 500 times as compared to the horizontal axis.

As is clear from Figures 3a and 3b, four longitudinal waves are generated on the surface of the composite plate in the comparative method without the deformation process of the present invention, but the generation of longitudinal waves is prevented in the method of the present invention. ing.

[Brief explanation of the drawing]

FIG. 1 is a side view schematically showing an example of the method of the present invention, and FIG. 2 is a side view schematically showing the arrangement of rollers in the deformation step. Further, Figures 3a and 3b are graphs showing the surface condition of the composite board, where Figure a shows the composite board produced by the method of the present invention, and Figure b shows the composite board produced by the comparative method. 1, 1': metal sheet, 2: thermoplastic synthetic resin sheet, 3, 3': uncoiler, 4, 4': take-up roller, 8, 8': thermocompression roller, 11,
11': Roller group for deformation process, 12: Cold air blower.

Claims (1)

[Claims] 1. A method for manufacturing a composite plate in which metal sheets are laminated on both sides of a thermoplastic synthetic resin sheet, comprising: (a) preheating two metal sheets stretched at a constant tension; (b) A bonding process in which a preheated metal sheet and a molten synthetic resin sheet are supplied between heated pressure rollers so that the synthetic resin sheet is interposed between the metal sheets to obtain a composite plate; (c) A deformation step in which the obtained composite plate is passed between a plurality of rollers arranged in a staggered manner so as to impart deformation to the composite plate within a degree equivalent to its bending elastic limit; (d) between the rollers in the deformation step; A method for producing a composite board, comprising: a cooling step of cooling the composite board so that the temperature of the synthetic resin falls below its softening point. 2. In the method described in claim 1,
A method for manufacturing a composite board, wherein the cooling step includes a cold air blower provided opposite to the rollers in the deforming step. 3. In the method according to claim 1 or 2, the roller used in the deformation step has a diameter of 50 to 50 mm.
A method for manufacturing a composite board characterized by a thickness of 200 m/m. 4. Production of a composite plate according to any one of claims 1 to 3, characterized in that the distance between the axes of the rollers in the deformation step is in the range of 0.5 to 2d relative to the roller diameter d. Method. 5. A composite plate according to any one of claims 1 to 4, characterized in that the thermoplastic synthetic resin sheet is a polyolefin synthetic resin sheet having a thickness of 1 to 10 m/m. manufacturing method. 6 In the method according to any one of claims 1 to 5, the metal sheet has a thickness of 0.05 to 0.5
A method for producing a composite plate, characterized in that it is an aluminum sheet or a steel sheet with a thickness of m/m.