JPH07189482A - Concrete form panels - Google Patents

Abstract

PURPOSE:To make the surface smooth and even by installing a resin sheet made of a mixture of polyethylene resin and pulp fiber to a front layer and the lowest layer and a wooden venner to an intermediate part, thereby laminat ing them. CONSTITUTION:A pulp resin sheet, which is a mixture of polyethylene resin and pulp fiber, is installed to a front layer 1 and the lowest layer 5. A wooden veneer, whose fiber direction is in parallel to the longitudinal direction, is installed to a second layer 2 and a fourth layer 4. A wooden veneer, whose fiber direction is at right angles to the longitudinal direction, is installed to a third layer 3. Furthermore, each layer of the layers from 1 to 5 is laminated and bonded with each other, thereby forming a concrete form panel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete formwork panel used for concrete construction.

[0002]

2. Description of the Related Art Conventionally, plywood mainly made from South Sea wood has been used for concrete formwork panels. However, the resources of South Sea lumber suitable for plywood production are rapidly decreasing, and the shortage of high-quality logs used for the surface layer of plywood is serious. On the other hand, in recent concrete construction, as the exposed surface of concrete is used as it is, and the tendency to omit mortar finishing is becoming stronger and stronger, the surface of concrete formwork panels is increasingly smooth and has no defects. It came to be requested.

Along with such changes in the demand structure for concrete formwork panels, metal and plastic concrete formwork panels have recently begun to appear in various markets. There are problems such as disposal of waste materials and cost increase, and there is nothing to satisfy.

[0004]

DISCLOSURE OF THE INVENTION The present invention is equivalent to the conventional plywood concrete formwork panel in the above-mentioned on-site cutting, waste material treatment, cost, and the like, and the conventional plywood concrete mold. The object is to provide a concrete formwork panel that is much smoother than the formwork panel.

[0005]

[Means for Solving the Problems] In the conventional plywood for concrete formwork, a good quality veneer without defects such as cracks and knot holes is selected and used for the surface layer, but the surface smoothness is still insufficient, It is not possible to cope with the recent construction methods that use exposed concrete surfaces as finishing surfaces.

The present invention has been solved by using, as a plywood front plate, a sheet which is low in cost and easy to dispose of waste materials and has various properties required for the plywood front plate. An idea similar to this is one in which phenol resin-impregnated paper is used instead of the front plate, but not only is phenol-impregnated paper costly, but it also has difficulties in treating waste materials after use as panels for concrete formwork. Therefore, it is rarely used at present.

According to the present invention, polyethylene flakes obtained by finely cutting waste polyethylene resin products such as food containers and waste paper pulp fibers obtained from waste paper products are formed into a sheet (hereinafter, this sheet will be referred to as "sheet"). Is simply used as the front and back plates of the plywood, and the conventional plywood manufacturing technology is applied to manufacture the panel. The manufacturing method will be described in detail below.

First, waste polyethylene products such as food containers are finely crushed to form polyethylene flakes, and the waste paper pulp fibers are mixed with the flakes to form a sheet. Examples of the forming method include the well-known wet papermaking method and wet forming method. The pulp resin sheet thus obtained is combined with a wood veneer as shown in FIG. 1 and laminated and bonded. That is, a pulp resin sheet is used for the surface layer and the bottom layer, a wood veneer whose fiber direction is parallel to the longitudinal direction of the panel is used for the second layer and the fourth layer, and a fiber direction is orthogonal to the longitudinal direction of the panel for the third layer. A wood veneer and a wood veneer are arranged, laminated in the thickness direction, and thermocompression molded into a plate-shaped panel.

In the structure of the laminate, the fiber directions of the wood veneer are all opposite to the fiber directions of the veneer of a normal plywood for concrete formwork. That is, in a normal plywood for concrete formwork, the fiber directions of the wood veneers of the second layer and the fourth layer are orthogonal to the longitudinal direction, and the fiber directions of the wood veneer of the third layer are parallel to the longitudinal direction. The fiber direction of the wood veneer of the plywood for concrete formwork is reversed because the tensile strength of the resin sheet is not as great as that of the wood veneer. This is because by imparting a predetermined bending strength required in the longitudinal direction by making the concrete form panel parallel to the longitudinal direction.

For the adhesion between the third layer and the second layer and between the third layer and the fourth layer, a urea melamine co-condensation resin adhesive or a phenol resin adhesive usually used for JAS type 1 plywood is used. You can use it. No adhesive is required to bond the pulp resin sheet and the wood veneer. If the temperature at which the polyethylene resin is semi-fluidized and the pressure required for ordinary plywood production are applied, the polyethylene resin of the pulp resin sheet is semi-fluidized to generate an adhesive force. The adhesive force thus generated causes the pulp resin sheet to adhere to the wood veneer, and the above five layers are integrated to form one panel.

The temperature at which the polyethylene resin of the pulp resin sheet becomes semi-fluid and exhibits an adhesive force is 180 to 20 degrees Celsius.
It is 0 degrees. At a temperature higher than this, the polyethylene resin is too fluidized and the sheet shape cannot be maintained. If the temperature is lower than this temperature, the polyethylene resin will not be sufficiently fluidized and a sufficient adhesive force cannot be obtained. Therefore, 180-degree Celsius
If you heat from the front and back of the laminate at a temperature of 200 degrees,
The polyethylene resin of the pulp resin sheet of the surface layer quickly becomes semi-fluid, and the surface layer and the bottom layer adhere to the second layer and the fourth layer, respectively. The adhesive used for adhering the third layer and the second layer and the third layer and the fourth layer may be an adhesive usually used for adhering plywood, but for the surface layer and the bottom layer, ordinary plywood production Since a high temperature is applied for a while, the pressing time can be appropriately lengthened or shortened depending on the curing conditions of the adhesive used.

Further, since the polyethylene resin is semi-fluidized, the surface layer and the bottom layer are adhered to the second layer and the fourth layer, respectively, and the surface state of the heat plate which is a heat medium is on the front surface and the back surface. Transcribed. Therefore, if the hot plate is provided with a predetermined three-dimensional pattern, the three-dimensional pattern can be transferred to the concrete form panel, and the three-dimensional pattern can be transferred to the concrete surface. Therefore, the concrete formwork panel of the present invention can be used not only for a general concrete formwork panel but also for the purpose of forming various three-dimensional uneven patterns on concrete.

Further, the pressing pressure at the time of adhesion may be a general plywood manufacturing condition, that is, a range of 7 to 15 kg / cm ² . When the temperature condition is in the range of 180 to 200 degrees Celsius, the pulp resin sheet maintains the sheet shape and the polyethylene resin is semi-fluidized, so that the pressing pressure can be appropriately selected in the range of 7 to 15 kg / cm ^2. .

As equipment used for the bonding step, equipment used for general plywood production can be used almost as it is. However, the pulp resin sheet and the wood veneer are adhered to each other by the adhesive force of polyethylene resin, and the polyethylene resin remains semi-fluidized at high temperature, so the adhesive force immediately after taking it out from the hot press is so strong. is not. Therefore, after the hot pressing is completed, it is necessary to hold the panel while pressing it until the adhesive strength of the polyethylene resin becomes sufficiently large until the panel is naturally cooled.

The polyethylene resin and the pulp fiber, which are the raw materials for the polyethylene resin sheet, can be used not only to supply an inexpensive concrete formwork panel but also to prevent pollution by exclusively using waste materials or those recovered from waste products. It is also significant from the point of view. Of course, in the present invention, not only waste materials or those recovered from waste products,
It goes without saying that polyethylene resin and pulp which are generally used as raw materials for products can be used.

[0016]

In the concrete formwork panel according to the present invention, in the panel manufacturing process, the polyethylene resin on the surface is in contact with the hot press hot plate and is semi-fluidized, so that the surface of the hot plate is transferred to the surface of the panel. It Therefore, if an extremely smooth hot plate is used, an extremely smooth surface can be formed on the surface of the panel. Therefore, if this panel is used as a concrete formwork panel, an extremely smooth concrete surface can be obtained.

A conventional concrete formwork panel made of a single wood veneer gradually becomes difficult to separate from concrete after being used many times. Therefore, even if it is used once or twice, the surface of the concrete becomes rough due to poor peeling, and it is often impossible to use up to the physical endurance limit. Since the polyethylene resin originally has a very poor adhesion to concrete, the concrete and the concrete form panel are easily peeled off even when the panel of the present invention is used as the concrete form panel 20 times or more. The concrete surface at that time is almost the same as the surface of the formwork, and can be used as a concrete formwork up to the physical endurance limit.
Moreover, the waste material treatment of the used concrete formwork, which is a problem at the construction site, does not generate toxic gas even if it is incinerated like the conventional wood concrete formwork.

Further, as mentioned above, since the smooth surface of the hot plate is transferred to the surface of the panel, if the hot plate is provided with a predetermined three-dimensional uneven pattern, the three-dimensional uneven pattern is also formed on the concrete formwork panel. Can be transferred, and the three-dimensional uneven pattern can be transferred to the concrete surface. Therefore, the concrete formwork panel of the present invention can be used not only for a general concrete formwork panel but also for the purpose of forming various three-dimensional uneven patterns on concrete.

[0019]

【Example】

(Example 1) Newspaper waste fiber 15%, polyethylene flake 85% by weight in dry state, thickness 5 mm, basis weight 9
A pulp resin sheet having a width of 930 mm and a length of 1860 mm at 00 g / m ² is arranged in the first layer and the fifth layer, and the second layer and the fourth layer have the same size and a thickness of 3.6 mm and a fiber direction. A celaya veneer parallel to the longitudinal direction and a ceraya veneer having a thickness of 2 mm with the fiber direction orthogonal to the longitudinal direction are arranged in the third layer, respectively. The adhesive was applied in a total amount of 350 g / m ² on the front and back sides, and bonded by a hot press for plywood under the following conditions.

Temperature: 180 ° C. Clamping pressure: 12 kg / cm ² Clamping time: 4 minutes 30 seconds After adhering, gently taking out from the hot press, stacking 50 sheets of the panel and pressing with a pressure of 6 kg / cm ² from above. While standing still for 2 hours and naturally cooling, a panel having a thickness of 11.5 mm was obtained.

According to the above. The obtained panels were subjected to a bending rigidity test of plywood for concrete formwork using a 900 mm width test piece based on the Japanese Agricultural Standards for plywood for concrete formwork,
Further, repeated boiling test of plywood for concrete formwork according to the same standard was conducted. The results are shown at the end. Separately from the above test, the concrete form was repeatedly used 20 times, but there was no problem of peeling from the concrete.

Further, the smoothness of the surface of the concrete using the panel was far superior to that of the conventional concrete form frame using the wood veneer as the surface layer.

Example 2 A pulp resin sheet having a width of 930 mm and a length of 1860 mm, having a dry weight of 25% kraft waste paper fibers and 75% polyethylene flakes, a thickness of 4.5 mm and a basis weight of 1000 g / m ^2. Hemlock veneer, which has the same dimensions and a thickness of 3.5 mm, and whose fiber direction is parallel to the longitudinal direction, is arranged in the first and fifth layers.
Hemlock veneers of the above dimensions having a thickness of 2.0 mm in which the fiber direction is orthogonal to the longitudinal direction are arranged in the layers, and the urea melamine co-condensation resin adhesive is added to the third layer of hemlock veneers in a total amount of 350 g / front and back. m ^{2 was} applied, and the other conditions were the same as in Example 1, and the components were bonded by a hot press for plywood.

After adhering, after gently removing from the hot press, 50 panels were piled up and left standing for 2 hours while being pressed with 6 kg / cm ² from above, and naturally cooled to a thickness of 11.5 mm.
Got a panel of.

In the same manner as in Example 1, the panel thus obtained was subjected to a bending rigidity test and a repeated boiling test of a concrete formwork plywood using a 900 mm-width test piece based on the Japanese Agricultural Standards of the concrete formwork plywood. The results are shown at the end. Separately from the above test, the concrete form was repeatedly used 20 times in the same manner as in Example 1, but there was no problem of peeling from the concrete, and the smoothness of the surface of the concrete was the same as in Example 1 in the conventional case. It was far superior to the concrete formwork.

(Example 3) In a dry weight ratio, newspaper waste paper fibers 15%, polyethylene flakes 85%, thickness 5 mm, basis weight 900 g / m ² , width 930 mm x length 186
A 0 mm pulp resin sheet is arranged in the first layer and the fifth layer, and in the second layer and the fourth layer, a ceraya veneer having the same size and a thickness of 3.6 mm and the fiber direction parallel to the longitudinal direction is used. Each layer has a 2 mm thick ceraya veneer of the above dimensions in which the fiber direction is orthogonal to the longitudinal direction, and the urea melamine co-condensation resin adhesive is applied to the third layer of celaya veneer in a total amount of 350 g / cm ² on the front and back sides. Bonding was done with a hot press with an embossed plate with a rough texture on the surface of the hot plate.

Hot pressing conditions such as temperature, pressing pressure and pressing time were the same as in Example 1, and after hot pressing, a foamed plastic sheet having a foaming ratio of 20 times was put between the panels on the upper surface of Example 1. It was cooled while being pressed under the same conditions as in 1.

Concrete work was carried out by using this as a concrete form, and a concrete surface having a rough textured surface was obtained. The same panel was used 5 times for the above purpose, but there was no problem with peeling from the concrete.

(Summary of Examples)

[Table 1]

[Brief description of drawings]

FIG. 1 is a sectional view of a concrete formwork panel according to the present invention.

[Explanation of symbols]

 1 Surface layer (pulp resin sheet) 2 2nd layer (wood veneer) 3 3rd layer (wood veneer) 4 4th layer (wood veneer) 5 5th layer (pulp resin sheet)

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 27/32 Z 8115-4F E04G 9/04

Claims (2)

[Claims] 1. A resin sheet made of a mixture of polyethylene resin and pulp fiber is arranged on the surface layer and the lowermost layer, and
A wood veneer whose fiber direction is parallel to the longitudinal direction is arranged in each of the layers and the fourth layer, and a wood veneer whose fiber direction is orthogonal to the longitudinal direction is arranged in the third layer, and the above layers are laminated and bonded in the thickness direction. Panels for concrete formwork that are characterized by: 2. The concrete formwork panel according to claim 1, wherein a three-dimensional concavo-convex pattern is formed on the surface of the surface layer.