JPS6168379A - Method of forming resin layer on surface of plywood for concrete frame - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a resin layer of polyolefin resin on the surface of plywood used as concrete formwork.

[Conventional technology]

Boards for concrete formwork are required to have impact resistance and durability due to the severe usage conditions, and at the same time, are required to be releasable from the concrete surface after concrete is poured.

Therefore, at the factory lζ, acrylic paint was applied to the surface of the board.
Urethane-based paints and the like have been applied, but this method has many problems due to the pollution caused by solvents such as thinner. Therefore, recently, boards with a resin film attached to the surface have begun to be used. As a method of pasting a resin film on the surface of a board, as in JP-A No. 58-128850, an adhesive polyolefin resin is first heat-sealed onto the plywood, and then a polyolefin resin film of the same type is placed on top of the adhesive polyolefin resin. There is one that is attached by placing it on the surface and applying heat and pressure.

[Problem that the invention seeks to solve]

The method disclosed in this (7)%lP No. 1988-128850 involves scattering thermoplastic synthetic resin powder onto a wooden board, and then melting the powder on the wood board using a heating device. This molten powder is passed between the costume press rolls to form an adhesive layer of uniform thickness, and a thermoplastic synthetic resin film is supplied on top of this adhesive layer and heated and pressed.
A resin layer is formed on the surface of a wooden board. In this method fζB, the upper layer (or upper surface) of the film is not melted, but only the lower layer (or lower surface) is melted, and the film and adhesive layer are bonded together with their interfaces melted together. However, the temperature range for creating such a molten state is very narrow, and it is difficult to control the temperature of the heating roll. For example, when the temperature reaches its peak, the pressure of water vapor generated from the plywood increases, pushing the film upward and creating bubbles. If the final temperature is too low, there is a problem that melting will be incomplete and adhesive strength will not be obtained.

In the present invention, even if water vapor is generated from the plywood, it is evacuated to the outside of the resin layer without forming air bubbles between the plywood and the wood Bw layer to ensure complete fusion, and the resin layer has strong adhesive strength to the plywood. The purpose of this invention is to provide a method for forming on the surface of plywood.

[Means for Solving the Problems J] The present invention involves spraying adhesive polyolefin resin powder on the surface of plywood, preheating the powder, and heating and pressing it with a heating roll to melt the resin powder. In a product that is fused to the plywood surface to form an air-permeable adhesive layer made of a bonding polyolefin resin on the surface of the plywood, the same type of non-adhesive polyolefin resin is applied as a surface layer agent on the adhesive layer. After supplying it in a completely molten state and applying pressure with heating rolls to form a non-adhesive polyolefin resin layer on the plywood surface, immediately blow cold air while passing through a group of cooling rolls. A sanitizing layer is formed on the surface of the plywood by rapidly cooling the surface of the resin layer to below the thermal deformation temperature of the resin.

[Effect]

The same type of non-adhesive polyolefin resin supplied as the Table 11 material is supplied in a completely molten T8 state on the adhesive layer in a molten state, so the adhesive layer and surface material are completely fused, making it strong. Adhesive strength is ensured, and water vapor generated from the plywood can penetrate this completely molten film, creating negligible small holes.
The pores are immediately pressurized with a cooling roll, and the holes are then cooled under pressure.At the same time as the pressure is cooled, cold air is blown out to rapidly cool the molten resin from the surface. It becomes smaller, stronger, and has a smoother surface.

[Example 1] The apparatus shown in FIG. 1 was used, and the heating roll 5 was 2
00°C1 The second heating rolls 9 are each set at 250°C, the cooling roll group 101ζ circulates cold water at 12°C, and the cold air device 12 is a Colder low-temperature air generator that applies the principle of portex tubes. 5C cold air was blown. An infrared heating furnace with a length of 4 m is used as the heating device 4, an electrostatic powder coating machine is used as the powder dispersing device 2, and the feeding speed of the roller conveyor 11 is 6 m/'I.
dl.

As the adhesive polyolefin resin powder 3, powder of ER resin ER61ON manufactured by Showa Denko K.K., particle size 50 was used.
~150 mesh was used, and HIZEX 8000F (low pressure polyethylene, melting point 133°C, manufactured by Mitsui Petrochemical Industries, Ltd.) was used as a non-adhesive polyolefin resin.
) was used in the form of pellets and strained using an extruder 6 so that the molten resin was discharged onto the plywood in a curtain shape from a T-die. Plywood 1 was a commercially available 5-ply product with a thickness of 12 mm. In addition, numeral 5' is a roll for the support of the heating roll 5, 9 is a roll for the support for the second heating roll 9, and 10' is a roll.
The bearings of the cooling roll group 10 are roll groups, and the bearings of rolls 5 and 9 do not require heating, and the 10 bearings of the roll group do not require cooling. - Apply 25 f? of the adhesive polyolefin resin powder 3 onto the plywood 1 that is being transferred to the roller conveyor 11? /M2 ratio
The powder 3 was melted by passing it under the heating device 4 while being dispersed, and the powder 3 was fused onto the plywood 1 using the heating roll 5 to form an air-permeable adhesive layer. Then, the non-adhesive polyolefin resin is supplied in a molten state from the T-die of the extruder 6 onto the adhesive layer in a curtain shape, and is pressed with a heating roll 9.

At this time, water vapor generated from the plywood broke through the resin layer, and some negligible small holes were observed on the surface of the plywood, but these small holes were closed when pressurized with Cooling Ro-Machi Roo OA. At the same time, the cold air device 12
The resin was rapidly cooled to below its heat deformation temperature (80°C) by blowing cold air from it, resulting in smaller crystals, increased strength, and a smooth surface with excellent impact resistance, core durability, and mold releasability. A board for concrete formwork was obtained.

It is preferable that the surface temperature of the cooling roll group 10 is maintained between 10°C and 20°C. In addition, since the first and second cooling rolls play the role of surface forming, the roll pressure is set to 20 to obtain a linear pressure of 9/cR, and the third and subsequent rolls are used to form the resin layer. Since the purpose is to lower the surface of the resin to a temperature below the thermal deformation temperature of the resin, the linear pressure was set at 5 kg 7 am. Moreover, the temperature of the cold air blown out from the cold air device was 5°C.

[Example 2] The apparatus shown in FIG. 2 was used, and the heating roll 5
is set at 200°C, and the second heating roll 9 is set at 250°C, cold water at 12°C is circulated through the cooling roll group 10, and the cooling air device i! For t12, a one-kolder low-temperature air generator was used, applying the principle of portex tubes.
Heating bag! 4, using an infrared heating furnace with a length of 4 m,
An electrostatic powder coating machine was used as the powder scattering machine 2, and the feeding speed of the roller conveyor 11 was 6 m71B. As the adhesive polyolefin resin powder 3, powder of ER resin ER61ON manufactured by Showa Denko K.K., particle size 50 to 15 is used.
As the non-adhesive polyolefin resin film 7 as the surface layer material, a film of HIZEX 8000F (low-pressure polyethylene, melting point 133° C.) manufactured by Mitsui Petrochemical Industries, Ltd. and having a thickness of 100 μm was used. Furthermore, plywood 1 was a commercially available product with a thickness of 12 mm and 5 plies.

In addition, reference numeral 5 indicates a roll for the heating roll 5, 9 indicates a roll for the second heating roll 9, 10' indicates a roll group for the cooling roll n10, and the holder indicates that the rolls 5 and 9 are heated, respectively. In addition, the ten roll groups do not require cooling. The rest was the same as in Example 1. The adhesive polyolefin resin powder 3 is uniformly spread at a ratio of 25y/M'' onto the plywood 1 transported by the roller conveyor 11, and then passed through the heating device 4 and the heating roll 5, and then film-wrapped. The film 7 as a surface layer material is fed out from the feeding device @8 via the film supply kite roll,
It is supplied so as to be in contact with the surface of the second heating roll 9. The film 7 that came into contact with the second heating roll 9 set at 250°C immediately (ζ) melts and forms a shape that is transferred to the surface of the plywood 1 as the roll rotates, and the plywood surface f
A resin layer is then formed.

The bow I was then rapidly cooled from the resin surface by the 10th roller 1 of the cooling roll IRIO, and the surface was formed to be smooth.Then, the resin was passed through the subsequent cooling roll group while being blown with 5°C cold air by the cooling air device 12. The resin was rapidly cooled to a temperature below the heat distortion temperature (80°C). As a result, some negligible small holes were observed between the second heating roll 9 and the cooling roll group, but one of the cooling roll groups 10
After passing through the lO-ru, it was not crushed and the surface became smooth and glossy. The surface resin layer of the small concrete formwork board thus obtained had extremely strong adhesion strength to the plywood, and was excellent in durability and mold releasability.

[Comparative example]

Figure 2 (Using the device shown, the temperature of the second heating roll 9 is set to 170°C, room temperature water of 24°C is circulated through the cooling roll group, and the cooling air device 12 is not operated. Other than that, the same plywood 11 as in Example 2, adhesive polyolefin resin powder 3, and non-adhesive polyolefin resin film 7 were used. A resin layer is formed by spraying, heating with a heating device 4, heating and pressing with a heating roll 5, supplying a film 7 on the top surface, and applying the adhesive by a second heating roll 9 heated to 170°C. After bonding the film 7 on the layer by heating and pressing, the sample was cooled with a cooling roll group 10 circulating water at 24° C., and the sample obtained in Examples 1 and 2.
In order to compare the adhesive strength with the samples obtained in J.
ISK68541? :, according to tensile speed 50 tm
The results of the 90° peel test are as follows.

As is clear from the above, according to the method of the present invention, the adhesive strength between the plywood and the resin layer is greatly improved compared to the conventional product.

〔Effect of the invention〕

In this way, in the present invention, a completely molten non-adhesive polyolefin resin is supplied onto the adhesive polyolefin resin layer formed by fusing the plywood 1ζ, and after being cross-pressed with a heating roll, The resin is quickly cooled and pressurized by the cooling rolls, and in addition to the cooling and pressurized by the cooling rolls, the cooling air device 11 blows cold air to cool the resin down to below its thermal deformation temperature, thereby eliminating the generation of air bubbles. ,
Complete fusion is achieved, the resin layer on the plywood surface is smooth and glossy, and the resin crystals are small, so the adhesive strength with the plywood is strong, and it has excellent durability and mold releasability.

[Brief explanation of the drawing]

The drawings are schematic side views of an apparatus for carrying out the method of the present invention, and FIG. 1 is a schematic side view of the device used in Example 1, and FIG. 2 is a schematic side view of the device used in Example 2 ( 1... Plywood, 2... Electrostatic powder coating machine, 3... Adhesive polyolefin resin powder, 4...
・Heating device, 5... heating roll, 6...
extruder, 7... non-adhesive polyolefin resin film, 8...
...Film unwinding device, 9...Second heating roll, 10...Cooling roll group,
11... Roll conveyor, 12...? &1Lft
! .

Claims (1)

[Claims] In products where a breathable adhesive layer made of adhesive polyolefin resin is fused to the surface of plywood, the same type of non-adhesive polyolefin resin is supplied as a surface layer agent in a completely melted state on top of the adhesive layer. After applying pressure with heating rolls to form a non-adhesive polyolefin resin layer on the surface of the plywood, the plywood is quickly passed through a group of cooling rolls while blowing cold air until the surface of the resin layer reaches a temperature below the heat distortion temperature of the resin. A method for forming a resin layer on the surface of a concrete formwork board, which is characterized by rapid cooling.