JPS59203673A - Manufacture of concrete form board and apparatus therefor - Google Patents

Abstract

PURPOSE:To manufacture the titled form board excellent in surface strength and releasability at a low cost, by forming an adhesive polyolefinic resin layer on the surface of plywood by hot press with a heating roll, and further forming a non-adhesive polyolefinic resin layer in the same way. CONSTITUTION:Plywood 1 for a concrete form board being carried by a roller conveyer 12 is circulated through a powder sprayer 3 to spread powdery adhesive polyolefinic resin 2 onto the plywood 1. Then, the plywood 1 is passed below a heater 4 to preheat the surface of the plywood 1 together with the powder 2 and then through heating rolls 5 to form an adhesive polyolefinic resin layer by hot press. Thereafter, a non-adhesive polyolefinic resin layer is formed thereon using the second powder sprayer 7, a heater 8 and the group 9 of heating rolls. Then, the plywood is immediately passed through press rolls 10 to flatten its surface while rolling it. Then, the plywood is cooled by the group 11 of cooling rolls. Hence, the plate 13 for a concrete form board is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and an apparatus for forming a strong and smooth coating of polyolefin resin on the surface of plywood used as concrete formwork.

The surface of plywood for concrete formwork is required to have impact resistance and durability, as well as formability with respect to concrete, due to the harsh usage conditions. In order to meet these demands, the present inventors have developed a method for forming a polyolefin resin film on the surface of plywood at low cost using powdered resin. Invented a method and device for improving Z properties.

Next, the method of the present invention will be explained.

FIG. 1 is a schematic diagram of an apparatus for carrying out the method of the invention. First, plywood 1 for concrete formwork is transferred to roller conveyor 1.
2i, the powder spreader 3 is advanced to spread adhesive polyolefin resin powder 2 on the surface of the plywood 1 by 10 to 2 times.
Spray at a rate of 0';i 7M2. As the adhesive polyolefin resin, a polyolefin resin which has been chemically modified to have adhesive properties, such as CMP, HA-40 manufactured by Tonen Petrochemical Co., Ltd., is used. The particle size of the powder is preferably 70 to 200 mesh, and it is preferable to use an electrostatic powder coating machine as the powder spreader 3. Next, the plywood surface is preheated together with the powder by passing it under a heating device 4 such as infrared rays, and then heated and pressurized by passing it through a heating roll 5 to firmly bond the adhesive polyolefin resin and the plywood and to minimize the unevenness of the plywood surface. In order to do this, the pressure of the heating roll 5 is maintained at a linear pressure of 30 Kg/cm or more to crush the protruding portions on the surface to form an adhesive polyolefin resin layer. Subsequently, the non-adhesive polyolefin resin powder 6 is spread onto the surface of the adhesive polyolefin resin layer through the second powder spreader 7. ;The attack rate can be adjusted as appropriate depending on the impact resistance and durability requirements of the product.
0 to 100 p/M2 is suitable.

The non-adhesive polyolefin resin is a general polyolefin resin that does not have adhesive properties, and is preferably the same type as the adhesive polyolefin resin used for the adhesive layer.The particle size is 70 to 200 mesh, and the grade is It is preferable that the molecular weight is as large as possible. Next, the resin powder is heated through a second heating device B, and then heated and pressed through a second heating roll group 9 to form a surface resin layer. The surface resin layer has an average thickness of 50 to 100 microns, and in order to completely melt it, two or more second heating roll groups 9 must be installed in succession to provide sufficient heating.

When the sufficiently heated and pressurized surface resin layer passes through the group of heating rolls, the temperature rapidly decreases from the surface and crystallization progresses. Even if pressure is applied after crystallization has progressed, no rolling effect will be produced, so it is necessary to apply pressure and shape with a pressure roll at f''fl, when crystallization begins.

The pressure roll is set at a temperature close to the softening temperature of the resin, so when it is pressed by the pressure roll, crystallization progresses, pressure is applied, and molding occurs at the same time, and there is no excessive cooling, making it ideal. It will be pressed under the temperature conditions of . In this way, a rolling effect is produced due to the pressing force, and directionality is created in the molecular arrangement. Therefore, the surface resin jm can be given physical properties similar to those obtained by bidirectional stretching, and its impact resistance is improved. Furthermore, if the roll surface of the pressure roll is mirror-finished, the finish of the resin surface after pressurization and molding will be good, and the releasability of concrete will be improved. After passing through the pressure roll 10, the surface is completely hardened and stabilized when it is cooled down to 70°C or less by the cooling roll 11.

Since the pressure roll has a rolling effect in the temperature range where resin crystallization progresses, it is desirable to maintain the temperature of the pressure roll between 90°C and 100'C.

Placing the pressure roll as close as possible to the final heating roll will prevent the crystallization of the surface resin layer from progressing. There is a limit to the shortening of the release heat radiation time to reach the pressure roll depending on the relationship.The limit of this release heat radiation time is about 3 seconds.If the feed speed is increased, 'r
Since the heating time for M Bs is short, there is a limit to the feeding speed. Therefore, the 9 auxiliary heating rolls 9s, which prevent the temperature from decreasing when the release heat dissipation time becomes long, have a complementary role to the second heating roll group 9, and the pressure may be low. Therefore, the roll diameter is relatively small (
It is necessary to install it as close to the pressure roll 10 as possible using a depth of 100 mm (φ).

The concrete formwork board manufactured by the method described above has a polyolefin-based surface and a layer of elbow fat on the surface.
ii1 Yamageki 1st student, i] Tokui student, r who excels in 1st student 1
Shows nature.

Next, a method of adding and using a fluorine resin will be explained. The fluorine-based resin is added to the non-adhesive polyolefin resin using a powder of low molecular weight tetrafluoroethylene. The appropriate amount of addition is 0.5 to 5%.

When fine powder of tetrafluoroethylene is added to the non-adhesive polyolefin resin that forms the surface, the releasability improves to less than 1i, so the adhesive strength decreases when the roll passes through the second heating roll group 9. This eliminates the protruding phenomenon of the resin surface when it enters the pressure roll, and prevents the surface of the resin from being partially cooled and hardened. Therefore, it goes without saying that the surface shape after passing through the pressure roll is much better, and the mold releasability of the product is improved.

Next, the present invention will be explained by examples.

<Example 1> The apparatus shown in FIG. 1 was used, and the heating roll 5 was
20'C, second addition iB% 0-le 1-n 9 is 190
°C1 The pressure roll 10 is set to 90"C, the cooling roll 11 is set to water-cooled temperature, and the infrared heating device d4 has a length of 4".
m, the length of the second heating device 8 was 2 m, the single-powder powder coater 3 and the second powder spreader 7 were powder electrostatic coating machines, and the feeding speed of the roller conveyor 12 was 10 m/min. As adhesive polyolefin resin powder 2, Tonen Petrochemical Co., Ltd. "Jk CMP, HA 40 70-1
50 mesh powder was used, and as the non-adhesive PoIJ iRefin resin powder, HiZEX 8200CP manufactured by Mitsui Petrochemical Industries, Ltd. was used. Also, plywood 1 has a thickness of 12
Mi'J, a commercially available 5-ply product was used.

On top of the plywood 1 is the CMP1-I manufactured by Tonen Petrochemical Co., Ltd.
A-40 adhesive polyolefin resin powder 2
After passing through the heating device 4 and passing through the heating roll 5 while uniformly scattering at a ratio of 0 yen/M2, the non-adhesive polyolefin resin powder of HiZEX 82oOCP manufactured by Mitsui Petrochemical Industries, Ltd. was sprinkled at a ratio of 80 f77M2. , and subsequently passed through a second heating device 8 and a second heating roll group 9, and then immediately passed through a pressure roll 10 and a cooling roll group 11 to perform surface finishing. At this time, the second
The distance between the rear roll of the heating roll group 9 and the pressure roll 1° is 450 mm IJ, and the heat radiation time is 2.7 mm.
It was seconds. In this way, a concrete formwork plywood 13 having excellent impact resistance, durability, and mold releasability was obtained.

<Example 2> As the non-adhesive polyolefin resin powder 6, HIZEX 8200BP manufactured by Mitsui Ishimagari Kagaku Kogyo Co., Ltd. and fluororesin Rublon Shi-5 manufactured by Daikin Industries, Ltd. were added at a ratio of 2% to a sufficient amount. Example 3 A plywood 13 for concrete formwork with better releasability was obtained using the same mixture as in Example 1. An auxiliary heating roll 9s shown in FIG. 2 is placed between the No. 2 heating roll group and the pressure roll.
The heating roll 5 was set at 220'C, the second
The heating roll group 9 is 190' (.

Auxiliary heating roll 9s is 200″c1 Pressure roll 10 is 9
0'C, the cooling roll group 11 is set to ice cold temperature,
The length of the infrared heating device 4 is 4nZ, and the length of the second heating device 8 is 277Z. is (3 m 7 min. The la of the final heating roll and pressure roll 10 of the second heating roll group 9
The distance between the auxiliary heating rolls 9s and the pressure roll is 2 (10mm IJ).The auxiliary heating rolls 9s
The pressure roll used was 80 mm, and the pressure roll was 300 mm. The same resin and plywood as in Example 1 were used, and the components from powder spreader 3 to second heating devices W and 8 were the same as in Example 1.
After passing through the second heating roll group 9, the resin surface on the surface of the plywood is reheated by an auxiliary heating roll 9s so that the temperature of the resin on the surface of the plywood does not drop. Send it to 10. The release heat radiation time from this auxiliary heating roll to the pressure roll was 2 seconds. After passing through the pressure roll, the plywood is taken out through the cooling roll.
Even though the feeding speed was slow, the heat was supplied from the auxiliary heating roll, so it did not crystallize before it entered the pressure roll, and the rolling effect was applied by the pressure roll, resulting in impact resistance and durability. A concrete formwork plywood 13 with excellent properties and preformability was obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of an embodiment of the apparatus of the present invention, and FIG. 2 is an enlarged side view of an embodiment in which an auxiliary heating roll is disposed between a second heating roll group and a pressure roll. . 1. Plywood, 2. Adhesive polyolefin resin powder,
3... Powder spreader, 4 - Heating device, 5... Heat roll, 6... Non-adhesive polyolefin resin powder, 7... Second powder spreader, 8... No. 2 heating device, 9 ・Second
Heat roll group, 9S/auxiliary heating roll, 10...pressure roll, 11...cooling roll group, 12...roller conveyor.

Claims (4)

[Claims] (1) Spread adhesive polyolefin resin powder on the surface of the plywood, preheat it, and then heat it with a heating roll.
Pressure is applied to melt the powder and form an adhesive resin layer on the plywood surface, followed by scattering the same type of non-adhesive polyolefin resin powder, preheating it, heating it again with a heating roll, and applying pressure. A concrete formwork characterized in that after a polyolefin resin layer is formed on the surface, it is immediately passed through pressure rolls to smooth the surface and at the same time is pressurized and shaped, and then the surface is cooled with cooling rolls. Method of manufacturing a board. (2) The method for producing a board for concrete formwork according to claim 1, characterized in that a fine powder of a fluorine-based resin is added to a powder of a non-adhesive polyolefin-based resin. (3) A powder spreader that spreads adhesive polyolefin uniform powder onto the surface of the plywood, a heating device that is disposed in the next step of the powder spreader and heats the powder spread on the plywood, and a heating device A heating roll is placed in the next process position to heat and press the heated powder, and it is suitable for the next process of the heating roll! Is there a non-adhesive powder placed on top of the powder? A second powder scattering machine that sprays Refine resin powder; a second heating device that is disposed in the next process of the first powder dispersion machine and heats the dispersed powder; and a second heating device that is disposed in the next process of the heating device. a second heating roll group that heats and presses the heated powder; and a pressure roll that is disposed in a step subsequent to the second heating roll group and smoothes the surface of the resin in a molten state, presses it, and molds it. 1. A manufacturing apparatus for a concrete formwork board, comprising: a group of cooling rolls for cooling the surface thereof. (4) The concrete according to claim 3, characterized in that an auxiliary heating roll is provided at a position as close as possible to a pressure roll disposed in the next step of the second heating roll. IJ - Upper formwork board mounting equipment.