JP2726943B2 - Concrete form board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention forms an overlay of a polyolefin resin on the surface of a wooden board used for a concrete form,
The present invention relates to a high-quality concrete formwork plate for improving the mold releasability and the number of diversions, and a method for manufacturing the plate at low cost.

<Prior Art> Various attempts have been made to overlay a polyolefin resin having excellent performance as a surface material of a concrete formwork on the surface of a formwork plate. For example,
JP-B-58-22334, JP-B-62-32109, JP-B-63-11984, JP-B-62-53343 and the like are known. JP-B-58-22334, JP-B-62-32109
JP-A-63-11984 and JP-B-63-11984 perform overlay processing by a method of heat-sealing on a substrate using a hot-melt type adhesive resin to obtain an excellent formwork plate. Is what you do. Further, Japanese Patent Publication No. Sho 62-53343 discloses a method of overlaying a polyolefin resin film on plywood with an adhesive directly.

<Problems to be Solved by the Invention> Since a polyolefin resin is originally nonpolar, it is necessary to heat-bond it with a hot-melt type of bonding resin to bond it onto an essential plate, because bonding costs and bonding costs are low. Although it is an advantageous method in terms of strength, the water in the wooden board evaporates rapidly due to heating, and water vapor expands at the same time as decompression, bubbles are generated in the molten resin, and the sheet is pushed up and the surface is pushed up In fact, production was difficult due to blistering.

In addition, the overlay plywood for concrete formwork manufactured by the conventional method uses natural wood as it is,
Cracks and pits are present on the substrate surface. Regarding the quality of one kind of plywood for concrete formwork of Japanese agricultural and forestry standard,
The existence of cracks with a width of 1.5 mm and insect holes with a major axis of 10 mm has been recognized. If such a concave portion is overlaid as it is, the portion becomes a bridge made of only the polyolefin resin sheet, and the physical strength is weakened.

Furthermore, the above-mentioned conventional method is to overlay a polyolefin-based resin film as a secondary process again on a plywood once manufactured, a wood board such as a particle board, etc. If overlay processing becomes possible at the stage of primary processing of manufacturing, it is expected that the cost of the manufacturing process will be drastically reduced.However, with the conventional technology, it is not possible to incorporate this overlay processing step into the primary processing line. There were various problems such as possible.

<Means for Solving the Problems> In order to solve the conventional problems, in the present invention, first, one side of a polyolefin resin film is subjected to an oxidation treatment by a method such as corona discharge machining, and then an adhesive is applied. Is used for laminating with a nonwoven fabric to produce a composite sheet in which the polyolefin resin film and the nonwoven fabric are firmly integrated. Then, a non-woven fabric having a polyolefin-based resin layer adhered to the surface thereof, and a non-woven fabric adhered under the adhesive by applying a reaction-curable adhesive between the non-woven fabric side of the composite sheet and the wooden board, and pressing and bonding. An overlay wood board for concrete formwork is provided which is adhered to the wood board via a layer and yet another adhesive and the non-woven fabric layer is impregnated with an adhesive. Adhesion between the polyolefin-based resin film and the nonwoven fabric can be performed under ideal conditions without restrictions such as wood-like shape and water content, so that a reliable adhesive strength can be easily obtained. The composite sheet thus obtained is then adhered to a wooden board. Since the adhesive of this composite sheet is a non-woven fabric, adhesion to wood is easy. In addition, in the case of thermocompression bonding using a thermosetting adhesive, there is an action of degassing the water vapor generated in the wood from around the fibers of the nonwoven fabric,
Vapor pressure is low and puncture does not occur. Therefore, by using the composite sheet, a wooden board manufacturing process, that is,
It became possible to finish the secondary processing overlay by incorporating it into the primary processing line. Here, the method for manufacturing the concrete formwork plate according to the present invention will be described in detail.

First, regarding the production of a composite sheet, a dry laminator that can continuously feed a polyolefin resin film and a nonwoven fabric is used. The polyolefin-based resin film is subjected to an oxidation treatment such as corona discharge machining or the like on the adhesion side in advance, and the surface is polarized. An adhesive is applied to the film, and after passing through a drying zone, the film is overlaid with a nonwoven fabric and heat-pressed with a nip roll. As the adhesive used here, aqueous vinyl urethane-based, epoxy-modified acrylic-based emulsion type, polyester urethane elastomer and the like can be used. The coating thickness of the adhesive is desirably slightly larger in consideration of the penetration into the nonwoven fabric fiber, and is suitably 30 to 50 g / m ² . In addition, about the manufacturing method of a composite sheet, you may use methods, such as a wet laminator other than the said dry laminator.

Next, the composite sheet thus obtained is bonded to a wooden board. First, as a first method, a reaction-curable adhesive is applied onto a wooden board such as a plywood, a particle board, or a wafer board. When the non-woven fabric side of the composite sheet is placed on the adhesive-coated surface and pressed by a press at room temperature, the reaction-curable adhesive penetrates into the gaps between the fibers of the non-woven fabric. After that, when heated and pressed using a hot press, the adhesive cures by reaction, so when the press is released, the adhesive strength is exhibited, and bubbles are generated even if some water vapor remains under the sheet Without doing this, a resin overlay wood board with high adhesive strength can be obtained. At this time, if the kind of the reactive curing adhesive is appropriately used, the bonding can be performed only by the cold press. It is also possible to apply a method of manufacturing continuously using a pressure roll.

A second method is a method of performing overlay processing in a process of manufacturing a wooden board.

When the wood board is plywood, during the deposition step in the plywood manufacturing process, the nonwoven fabric surface of the composite sheet is polymerized via the same adhesive on the outermost side of the veneer group laminated by applying a plywood adhesive, After that, if heating and pressing using a hot press under the same conditions as when manufacturing ordinary plywood, the composite sheet is bonded to the surface simultaneously with the bonding of the veneer group, so it is very easy to obtain a resin overlay plywood be able to. However, the temperature of the hot press must be a temperature that does not reach the melting point of the resin constituting the composite sheet.

When the wooden board is a particle board or a wafer board, a thermosetting adhesive is applied to the nonwoven fabric side of the composite sheet, chips or wafers are formed thereon, and the composite sheet is formed using a hot press. If hot pressing is performed at a temperature below the melting point of the resin, the resin film overlay can be formed simultaneously with the curing and molding of the particle board and the wafer board.

As the reaction-curable adhesive used in the first method, any of urea resin, melamine resin, phenol resin, urethane-based resin, epoxy-based resin, ultraviolet-curable resin, and the like can be used. For example, a commonly used wood adhesive can be used, but a plate having poor water resistance cannot be used because it is a plate used as a concrete formwork.

The adhesive used in the second method can be used almost as it is if it is a thermosetting adhesive used for plywood.

<Operation> If a polyolefin resin film, which is originally difficult to bond due to its molecular structure, is to be firmly bonded directly to a wooden board, temperature conditions, moisture contained in the wooden board, and the shape of the wooden board are restricted. Although there are many elements, it is difficult to obtain ideal bonding conditions.In the present invention, first, a polyolefin resin film and a nonwoven fabric are first bonded to produce a composite film, and then the composite film is produced. Since the nonwoven fabric side is bonded to a wooden board, the nonwoven fabric has an effect of realizing strong adhesion with a polyolefin resin film.
Next, it has a very advantageous property that sufficient adhesive strength can be obtained even with an inexpensive wood adhesive to a wooden board, and at the time of bonding processing, an action of allowing generated steam to escape along the periphery of the fiber. To eliminate water vapor damage during the bonding process. In addition, due to the deaeration, it is possible to realize simultaneous overlay processing using composite sheets in the process of manufacturing a wood board such as plywood, particle board, and wafer board.

Furthermore, even when the overlay sheet becomes a bridge due to cracks, insect holes, etc. on the surface of the wooden board, the fibers of the nonwoven fabric are long, so that the function of reinforcing the film is maintained, and the strength of the bridge portion is maintained.

<Example 1> First, production of a composite sheet will be described with reference to FIG.

A polyolefin resin film 1 is a commercially available biaxially oriented reinforced polypropylene film having a thickness of 30 μm, one surface of which is oxidized by corona discharge machining, and an adhesive 2 for polyester urethane elastomer dry lamina manufactured by Aika Kogyo Co., Ltd. Using an adhesive, the non-woven fabric 3 was made by Asahi Kasei Kogyo Co., Ltd.
/ m ² was used. The polyolefin film 1 is fed out with the oxidized surface facing down, and an adhesive 2 is applied between the gravure roll 4 and the rubber roll 5. The adhesive was attached to the surface of the gravure roll 4, the excess was scraped off with a doctor blade 6, and the setting was made such that the adhesive could be applied on the film at a rate of 50 g / m ² . The film 1 coated with the adhesive is heated and semi-dried by a radiation type drying device 7, polymerized with the nonwoven fabric 3, and pressure-bonded between a rubber roll 8 and a heating roll 9 to form a composite sheet 10. was taken.

Next, a concrete form plate manufactured using the composite sheet 10 thus manufactured will be described with reference to FIG. A commercially available 12 mm thick 5-ply plywood is used as the wood board 11, and a mixture of melamine urea resin adhesive UM82 manufactured by Aika Kogyo Co., Ltd. and UM82 mixed with 10% flour is used as the adhesive 12, and 200 g / m ² , the non-woven fabric 3 side of the composite sheet 10 obtained above was placed with the adhesive facing the adhesive, and after a cold pressure of 20 minutes, a pressure of 5 kg / cm ^{2 at} a temperature of 105 ° C. and 5 kg / cm ² was obtained.
After hot-pressing for a minute, it was taken out, and no bubbles were generated at the time of decompression, and an overlay plywood for concrete formwork in which the sheet and the plywood were firmly bonded was obtained.

<Example 2> Wood board using composite sheet 10 obtained in the same manner as in Example 1
A wafer wood having a thickness of 17.2 mm manufactured by Louisiana Pacific Co. of the United States was used as 11, and as an adhesive 12, a flour 2 was added to a phenolic resin adhesive P-82H manufactured by Aika Kogyo Co., Ltd.
A mixture of 0% is applied to the surface of the wafer wood at a rate of 250 g / m ² , the composite sheet 10 is placed thereon, and after a cold pressure of 20 minutes, a temperature of 110 ° C. and a pressure of 5 kg After hot-pressing for 7 minutes under the condition of / cm ² , no air bubbles are generated at the time of decompression, the composite sheet and wafer wood are firmly adhered, and the surface is smooth and the resin overlay is used for concrete formwork with resin overlay A plate was obtained.

<Example 3> A composite sheet 10 obtained in the same manner as in Example 1 was used.
200 g of melamine urea resin adhesive UM82 manufactured by Aika Kogyo Co., Ltd. mixed with 20% flour as adhesive 12
/ m ² after application, 9 layers are superimposed on the curved wooden mold of R600 so that each fiber direction is orthogonal, and the composite sheet is superimposed on both outer sides with the same adhesive, and high frequency is applied on the outer surface. Thus applying a heating electrode plate is pressed against the curved wooden, and heated at a high frequency while pressurized to a pressure of about 5 kg / cm ^2, the internal temperature 8
The adhesive was completely cured when it was heated and pressed for about 20 minutes at about 0 ° C to 100 ° C, and the board thickness was about 12 mm.
An R600 curved concrete formwork plate (FIG. 3) overlaid on both sides with a polyolefin-based resin sheet was obtained.

<Example 4> As the nonwoven fabric 3, a nonwoven fabric 805 manufactured by Miki Tokushu Paper Co., Ltd.
An overlay plywood having excellent performance as a concrete formwork plate was obtained in the same manner as in Example 1 except that the composite sheet 10 was formed using −20 and a thickness of 20 g / m ² .

<Example 5> Using a composite sheet 10 obtained in the same manner as in Example 1, 20% flour was mixed with a phenolic resin adhesive P-82 manufactured by Aika Kogyo Co., Ltd. as an adhesive 12 on the nonwoven fabric surface of the composite sheet. and ones is applied at a rate of 200 g / m ^2, a chip crusted the adhesive thereon was placed in the particle size forming separate, temperature 145 ° C., under a pressure of 15 kg / cm ^2, heat-pressed, 15 After 15 minutes, when decompressed and taken out, a resin-overlaid particle board with a thickness of 15 mm having excellent performance as a concrete formwork plate was obtained.

<Example 6> Except for using a composite sheet 10 obtained in the same manner as in Example 1 and using a wafer as a wooden board, the composite sheet 10 has excellent performance as a concrete form plate in the same manner as in Example 5. A 15 mm thick resin overlay wafer board with a smooth surface was obtained.

<Example 7> Melamine urea resin adhesive UM manufactured by Aika Kogyo Co., Ltd.
After applying a mixture of 82% and flour 10% at a rate of 200 g / m ² , five layers are alternately stacked so that the fiber directions are orthogonal to each other, and the same adhesive as the adhesive 12 is applied thereon in the same ratio. After coating, a composite sheet obtained in the same manner as in Example 1
When 10 were stacked and heated and removed for 4 minutes under the conditions of a temperature of 120 ° C. and a pressure of 15 kg / cm ^2, a plywood for a concrete formwork having excellent performance was obtained without decompression due to air bubbles caused by steam.

<Effect of the Invention> Since the concrete formwork plate according to the present invention has a polyolefin-based resin on the surface, components in the wood that affect the hardening reaction of the ready-mixed concrete are blocked by the surface resin, and There is no fear of causing obstacles. In addition, when the mold is released after the concrete is hardened, the polyolefin resin is non-polar, so that it is easily removed without being fixed, and the concrete molded product is not damaged. Furthermore, since the polyolefin resin is chemically stable, it does not change even when exposed to the alkali, moisture, heat and the like of the ready-mixed concrete for a long time, and has an excellent performance that it can be used many times repeatedly. In terms of structure, the nonwoven fabric is integrated under the polyolefin resin layer, so the strength of the surface material is high, and even if there are some defects on the surface of the base wood board, it is enough to cover it can.

The first characteristic effect of the method of the present invention is that when a polyolefin-based resin film is adhered onto a wooden board, the film and the nonwoven fabric are first completely adhered to each other and then adhered to the wooden board. It is easy to secure the adhesive strength between the resin and the nonwoven fabric. The second characteristic effect is that when the composite sheet and the wooden board are bonded by heating, the presence of the nonwoven fabric makes it easy for water vapor to escape, and does not cause air bubble damage. Therefore, by inserting the composite sheet into the wood board manufacturing run-in, a very simple overlay processing method can be realized in which the original wood board is completed and the overlay of the resin sheet is completed. Therefore, the work of repairing the surface of the wooden board can be omitted, and the adhesive to the wooden board can be an ordinary adhesive. The present invention can provide a concrete formwork plate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a method for producing a composite sheet used in the present invention, and FIGS. 2 and 3 are sectional views of an embodiment of a concrete formwork plate according to the present invention. 1 ... polyolefin resin film, 2 ... adhesive, 3 ... nonwoven fabric, 10 ... composite sheet, 11 ... wood board, 12 ... adhesive,

Claims (5)

(57) [Claims] 1. A nonwoven fabric side of a composite sheet formed by bonding a nonwoven fabric with an adhesive to a lower surface of a polyolefin resin film having a lower surface subjected to an oxidation treatment, and the nonwoven fabric side is attached to one or both surfaces of the wooden board via the adhesive. A concrete formwork plate adhered and having the nonwoven fabric layer impregnated with an adhesive. 2. A polyolefin resin film is subjected to an oxidizing treatment on one side, and then a non-woven fabric is bonded using an adhesive to form a composite sheet. The composite sheet and the wooden board are attached to the upper surface of the wooden board or A concrete formwork which is polymerized via a reaction-curable adhesive applied to the nonwoven fabric surface of a composite sheet, and is bonded by hot or cold pressing at a temperature not reaching the melting point of the resin constituting the composite sheet. Manufacturing method 3. A polyolefin resin film is subjected to an oxidizing treatment on one side, and then a non-woven fabric is bonded using an adhesive to form a composite sheet. Polymerizing via a thermosetting adhesive applied to the outermost surface of the composite sheet or the non-woven fabric surface of the composite sheet, and hot-pressing this at a temperature not reaching the melting point of the resin constituting the composite sheet to perform overlaying simultaneously with the production of plywood A method for producing a plate for a concrete formwork, characterized in that: 4. After subjecting one surface of the polyolefin resin film to an oxidation treatment, a nonwoven fabric is bonded using an adhesive to form a composite sheet, and the composite sheet is used in a particle board or wafer board manufacturing process. A thermosetting adhesive is applied to the nonwoven fabric surface of the composite sheet and polymerized on the outside of the particle or wafer small particle layer, and this is heated and pressed at a temperature not reaching the melting point of the resin constituting the composite sheet, and the particle board or wafer is heated. A method for producing a plate for a concrete formwork, wherein overlay is performed simultaneously with molding of a board. 5. The method according to claim 2, wherein a biaxially stretched polypropylene film is used as the polyolefin-based resin film.