JPH02301405A - Plate for concrete frame and its manufacture - Google Patents

Abstract

PURPOSE:To eliminate repairing of a woody plate surface and manufacture a plate for concrete frame, inexpensive and of superior quality, by means of an inexpensive adhesive by heat fusion bonding a polyolefin group resin film with a non-woven cloth to form a composite sheet and gluing the composite sheet to a woody plate. CONSTITUTION:While a polyolefin group resin film 1 and a non-woven cloth 2 are fed out respectively, bonding polyolefin group copolymerized resin 3 is discharged on the film 1, and while the resin is inserted between the film and non-woven cloth 2, the resin is laminated and pressurized between a pressure roll 5 and a cooling pressure roll 6 to completely fusion bond the copolymerized resin 3 in the molten state with the film 1. While being permeated into the spaces of fibers of the non-woven cloth 2, the resin is cooled and solidified and completely cooled by a cooling roll 7 and a composite sheet 8 constituted of the polyolefin group film and the non-woven cloth firmly integrated together with is manufactured. As for a woody plate 10, a plywood for the frame is used, and a reaction curing type adhesive 11 is applied between the non-woven cloth 2 side of the composite sheet 8 and the woody plate 10, pressed and bonded to manufacture an overlay woody plate for the concrete frame.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention forms an overlay of polyolefin resin on the surface of a wooden board used for concrete formwork, thereby improving the demoldability of the formwork and increasing the number of reuses. The present invention relates to a method for manufacturing concrete formwork plates and chain plates of relatively high quality at low cost.

<Prior Art> Various attempts have been made to overlay the surface of a formwork board with a polyolefin resin that has excellent performance as a surface material for concrete formwork. For example, Japanese Patent Publication No. 58-22554.

Special Publication No. Sho f; 2-55545, Special Publication No. Sho 63-119
Publication No. 84 and the like are known.

The above-mentioned Japanese Patent Publication No. 58-22334 and Japanese Patent Publication No. 63-1
The method disclosed in the 1984 publication is a method of thermally bonding onto a substrate using a hot melt adhesive, and
Japanese Patent Publication No. 62-53343 discloses a method in which one side of a polyolefin-based [111 sheet is subjected to corona discharge machining, an adhesive is applied to the sheet, and the sheet is pasted onto plywood.

<Problems to be Solved by the Invention> Since polyolefin resins are inherently non-polar, they have the property of not adhering to materials other than polyolefin materials.

Therefore, as mentioned above, in order to overlay a polyolefin resin sheet on a wood base material, corona discharge machining is applied to the adhesive side of the sheet to impart polarity to some of the surface molecules, and then the adhesive Therefore, it is necessary to use an expensive adhesive such as an epoxy-modified acrylic resin adhesive. However, there were still some parts that were unsatisfactory in terms of the adhesive strength of the product. In addition, in order to ensure the adhesive strength between the polyolefin resin sheet and the wooden board, there is a method of thermally fusing it using a hot melt adhesive or an adhesive polyolefin copolymer resin, but in this case, Currently, there are many problems in the manufacturing process, such as the moisture in the wooden board evaporating and the steam pushing up the sheet when the heat press releases the pressure, causing blisters on the surface.

Furthermore, in all of the above conventional methods, once commercialized plywood,
This involves overlaying a polyolefin resin sheet on top of a wooden board such as particle board as a secondary process, but if overlay processing becomes possible during the primary processing stage of manufacturing wood boards such as plywood, it would be possible to improve the manufacturing process. However, with the prior art, it has been impossible to incorporate this overlay processing process into the next processing line.

Also, an overlay wood board manufactured by a conventional method,
In particular, since plywood and the like are made of natural wood, there are cracks and holes on the surface of the base material.

Regarding the quality of the board surface of type 1 plywood for concrete formwork according to the Japanese Agricultural Standards, cracks with a width of 1.5 mm and exit holes with a major diameter of 10 mm have been observed, and such concave parts cannot be overlaid as they are. Then, there was a problem in that the portion became a bridge made only of the polyolefin resin sheet, and the physical strength was weakened.

<Means for solving the problems> In order to solve the above problems, in the present invention, first,
A composite sheet having an adhesive polyolefin copolymer resin between a polyolefin resin film and a nonwoven fabric and impregnating the inside of the nonwoven fabric with the resin is then manufactured, and then the nonwoven fabric side of this composite sheet and a wooden board are bonded together. By applying a reaction-curing adhesive between the two and applying pressure and bonding,
A polyolefin resin layer on the surface, an adhesive polyolefin copolymer resin layer below it, a nonwoven fabric layer impregnated from both sides with the same resin and a reaction-curing adhesive, and then firmly attached to the wooden board through the adhesive. Overlay wooden boards for glued concrete formwork can be obtained.

Therefore, the method for manufacturing a concrete form board according to the present invention will be described in detail.

First, a laminator that can feed the polyolefin resin film and the nonwoven fabric continuously is used. The adhesive polyolefin copolymer resin is discharged in a high-temperature molten state between the film and the nonwoven fabric in a curtain shape using an extruder and a T-die, and immediately pasted through a pressure roll, and when pressed, the molten state is The adhesive polyolefin copolymer resin is completely fused with the polyolefin 1M8'tl film on the surface, and penetrates into the gaps between the fibers of the nonwoven fabric and is strong. After developing strong adhesive properties and strongly adhering to fibers, it is cooled and solidified to obtain a composite sheet.

The composite sheet thus obtained has 1 to 181 polyolefin layers on the surface, an adhesive polyolefin copolymer resin layer below the layer, and a nonwoven fabric layer moderately impregnated with the resin. As for the method for manufacturing the composite sheet, for example, a method may be used in which nonwoven fabric is continuously supplied and laminated thereon using a coextruder that simultaneously extrudes two types of polyolefin resin and adhesive polyolefin copolymer resin. Alternatively, it can be easily produced by first forming a film of 2 m of resin, layering it with a nonwoven fabric, and heat-sealing it using a hot press. What should be noted here is that when manufacturing a composite sheet, temperature, pressure, time, etc. should be adjusted in consideration of the relationship between the melt properties of the adhesive polyolefin co-bonded resin and the degree of voids in the nonwoven fabric. Therefore, it is important that the resin penetrates into the inside of the nonwoven fabric appropriately. If penetration is incomplete, the anchoring effect will be insufficient and the adhesive strength will decrease. On the other hand, if the resin permeates excessively, the resin will protrude to the back side of the nonwoven fabric, which will become an obstacle when adhering the composite sheet and the wooden board.

Next, a wooden board is manufactured by overlaying this composite sheet.The first method is to apply a reaction-curing adhesive onto a wooden board such as plywood, particle board, or wafer board. Place the composite sheet on top with the nonwoven fabric side facing the adhesive-coated surface, and use a hot press to press the composite sheet at a temperature that does not reach the melting point of the resin that makes up the composite sheet, or use a cold press to heat it at room temperature. By applying pressure, the adhesive penetrates into the gaps between the fibers of the nonwoven fabric, and then the adhesive hardens due to a reaction. When the press is released, the adhesive has already exerted its adhesive strength, and some water vapor is released under the sheet. Resin-overlaid wood boards with high adhesive strength can be obtained without generating air bubbles even if they remain.

The second method is to perform overlay processing during the manufacturing process of the wood board.

If the wood board is plywood, during the plywood manufacturing process, a plywood adhesive is applied to the outermost side of the stacked veneers and the nonwoven fabric surface of the composite sheet is polymerized using the same adhesive. Then, by applying heat and pressure using a heat press in the same way as when manufacturing general plywood, the composite sheet is also bonded at the same time as the veneers, making it very easy to obtain resin overlay plywood. be able to. However, the temperature of the hot press must be below the melting point of the resin constituting the composite sheet.

If the wooden board is particle board or wafer board, apply a thermosetting adhesive to the nonwoven side of the composite sheet.
If chips or wafers are formed on top of the composite sheet and then hot-pressed and molded using a heat press at a temperature that does not reach the melting point of the resin constituting the composite sheet, a resin overlay board can be obtained at the same time as the particle board or wafer board is cured and molded. It will be done.

As the reaction-curing adhesive used in the first method, any of urea resin, melamine resin, phenol resin, urethane resin, epoxy resin, ultraviolet curable resin, etc. can be used, and mixing or co-condensation of these resins can be used. Any commonly used wood adhesive can be used. Furthermore, vinyl acetate emulsion resin, flour, etc. may be used for increasing the volume or for other purposes. Moreover, the adhesive used in the second method can be applied as is, if it is a thermosetting adhesive used for plywood or the like.

<Function> The nonwoven fabric of the present invention has the effect of connecting and adhering the polyolefin resin, which is originally difficult to bond due to its molecular structure, and the wood board using the fibers of the nonwoven fabric. As a method of bonding polyolefin resin and wood board, it is easy to bond the adhesive polyolefin copolymer S resin to the wood by heating it to melt it, but this method does not allow overlaying on the wood board. If you try to do this, the moisture in the wood will turn into water vapor and generate a large amount of water vapor, and when the pressure is released, the molten resin will be pushed up and bubbles will be formed, making it impossible to overlay.
If a composite sheet with non-woven fabric is used, it can be bonded to the wooden board at a temperature below the melting point of the resin that makes up the composite sheet, so there is no need to worry about air bubbles being generated when the press is released, and the polyolefin resin and the wooden board can be bonded well. Can be glued to. That is, the nonwoven fabric constituting the composite sheet is first bonded to a polyolefin resin film by thermocompression, impregnating the resin into the gaps between the fibers and strongly adhering the film. Next, when adhering to a wooden board using a reaction-curing adhesive, the adhesive easily penetrates between the fibers of the nonwoven fabric and hardens by reaction. In this way, the nonwoven fabric is impregnated with an adhesive polyolefin copolymer resin from one side and a reactive adhesive from the other, and the fibers connect both resins, filling almost all of the voids. It comes to work.

Another function of composite sheets is when overlaying wooden boards using reaction-curing adhesives, especially thermosetting adhesives, and during overlaying processes in the manufacturing process of plywood, particle boards, and wafer boards. When performing this process, it is generally very difficult to remove the water vapor generated during the heat pressing process that remains directly under the sheet because the sheet has no air permeability. In the case of , there is a nonwoven fabric directly under the polyolefin film, and most of the voids are impregnated with resin and adhesive, but a few voids are left around the thin fibers, and these voids are filled with water vapor. Since this is the degassing route, the amount of water vapor remaining directly under the sheet is extremely small, which helps prevent problems such as bubbles, blisters, and banks during depressurization.

The m fat overlay wood board manufactured in this way is
For relatively small depressions such as cracks and holes on the board surface, the resin sheet in the bridge area is not covered with polyolefin resin alone, but with a composite sheet integrated with nonwoven fabric, which improves physical strength, especially This results in increased stiffness.

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

As the polyolefin resin film 1, a 40μ thick film of Shiso Urex 2010HF manufactured by Showa Denko Co., Ltd. was used, as the nonwoven fabric 2, Nilux N-5040 manufactured by Asahi Kasei Co., Ltd. was used, and as the adhesive polyolefin copolymer resin 3, a film of Showa 4 was used. Using Kogyo ER resin ER523L,
Temperature 240°C 1 Discharge thickness 2 through extruder 4 with T-die
The film 1 and nonwoven fabric 2 are each fed out at a speed of 15 m/min, and the copolymer resin 3 is discharged onto the film, and while being sandwiched between the film 1 and the nonwoven fabric 2, the pressure roll 5 and When laminated and pressurized with the cooling pressure roll 6, the molten copolymer resin 3 is completely fused to the film 1, penetrates into the gaps between the fibers of the nonwoven fabric 2, and is cooled.
It was solidified and completely cooled by the cooling roll γ, and wound up onto a take-up roll 9 to form a composite sheet 8 in which the polyolefin resin film and the nonwoven fabric were firmly integrated.

Next, a concrete formwork plate manufactured using the composite sheet 8 thus manufactured will be explained with reference to FIG. 2.

As the wooden board 10, a commercially available plywood for formwork with a thickness of 12 mm and 5 brias was used, and as the adhesive 11, a mixture of melamine urea m fat adhesive UM-82 manufactured by Aikanigyo Co., Ltd. and 20% wheat flour was used. 20Of/M on the plywood! The nonwoven fabric 2 side of the composite sheet 8 obtained earlier was placed facing the adhesive, and after cold pressing for 20 minutes, the temperature was 105°C and the pressure was 5°C.
After heat-pressing for 5 minutes under the conditions of 9/d, the sample was taken out.
No air bubbles were generated during decompression, and an overlay plywood for concrete formwork was obtained in which the sheet and the plywood were firmly bonded.

<Example 2> A composite sheet 8 obtained in the same manner as in Example 1 was used, the wooden board 10 was Wafer Wood made by Louisiana Pacific Co., Ltd., and the adhesive 11 was Aikanigyo Co., Ltd.'s Hibi Phenol Resin Adhesive P-. Using a mixture of 82H and 20% wheat flour, spread it on the surface of the wafer wood at 250%.
The composite sheet 8 is placed on top of the coating at a ratio of 1/M', and after 20 minutes of cold pressing, the temperature is 110"C1 and the pressure is 5/c1.
When the composite sheet and wafer wood were firmly adhered to each other, no air bubbles were generated when the pressure was released, and the concrete formwork board with the resin overlay had a smooth surface and a tough resin overlay. was gotten.

<Example 5> A composite sheet 8 obtained in the same manner as in Example 1 was used, and the wooden board 10 was a 1.3 mm thick South Sea wood lauan veneer and urea resin adhesive UO-120 manufactured by Aikanigyo Co., Ltd. After applying an appropriate amount of a mixture of 10% wheat flour to
9 so that each M4 fiber direction is perpendicular to the curved wooden mold.
A composite sheet is stacked on both outer surfaces of the stacked sheets, and the outer surface of the composite sheet is pressed onto a curved wooden mold by applying an i-plate for high-frequency heating, and heated with high frequency while applying a pressure of about 5 kg/d.
2a so that the internal temperature is around 801C to 100C.
After heat-pressing for a minute, the adhesive was completely cured and a 1'L600 curved concrete formwork board (Fig. 3) with a thickness of about 12 mm and overlaid with a 1m polyolefin sheet on both sides was obtained. Ta.

<Example 4> An overlay plywood having excellent performance as a board for concrete formwork was obtained in the same manner as in Example 1 except that Eltas E5040 manufactured by Asahi Kasei Corporation was used as the nonwoven fabric 2.

<Example 5> Same as Example 1 except that as the polyolefin-based antigreasing film 1, a 50 μm thick film of Shifu Aroma-FA210 manufactured by Showa Denko Co., Ltd. was used, and as the nonwoven fabric 2, Penliese JP601 manufactured by Asahi Kasei Kogyo Co., Ltd. was used. In the same manner, a composite sheet was first manufactured.

Then, as adhesive 11, a mixture of phenol melamine resin adhesive P-85 manufactured by Aikani Gyo Co., Ltd. and 15% wheat flour was applied to this composite sheet at a ratio of 18Of/M'', and the same adhesive was sprinkled on top. The chips were formed according to particle size, and the temperature was 145°C and the pressure was 16ky/d.
When hot-pressed under the following conditions and decompressed and taken out after 15 minutes, a 12 mm thick W resin overlay particle board with excellent performance as a board for concrete formwork was obtained.

<Example 6> To obtain a 15 mm thick resin overlay wafer board with a smooth surface and excellent performance as a board for concrete formwork in the same manner as in Example 5 except that wafers were used instead of chips. was completed.

<Example 7> As the wooden board 10, a veneer of South Sea wood lauan with a thickness of 2.4 tons was mixed with an adhesive and 20% of melamine urea G8 fat adhesive UM-821ζ flour manufactured by Aikanigyo Co., Ltd.
After coating at a ratio of 00 f/Mt, five sheets were stacked alternately so that the fiber directions were perpendicular to each other, and the same adhesive was coated on top of them at the same ratio, and then manufactured in the same manner as in Example 5. Layer composite sheets, temperature 120℃, pressure 15kti
When the plywood was hot-pressed for 4 minutes under the conditions of /a4 and taken out, no damage caused by water vapor occurred during depressurization, and a plywood for concrete formwork with excellent performance was obtained.

<Effects of the Invention> Since the concrete formwork board according to the present invention has a polyolefin resin on the surface, the components in the wood that affect the hardening reaction of fresh concrete are blocked by the resin on the surface, so it is less resistant to concrete. There is no need to worry about causing any damage. Furthermore, when the concrete is removed from the mold after hardening, the olefin resin is non-polar, so it can be removed easily without sticking, and the concrete molded product will not be damaged.

Furthermore, polyolefin resins are chemically stable, so
It has excellent properties such as being able to be used repeatedly without changing even when exposed to fresh concrete's alkali, moisture, heat generation, etc. for a long period of time. In addition, since the m#I nonwoven fabric is integrated under the polyolefin resin layer, the surface material has high strength and can be used even if there are some imperfections on the surface of the base wood board. I can cover it. A similar product using paper instead of non-woven fabric was previously proposed by the present inventors, but non-woven fabric mainly uses filaments with extremely long fluorine ml/a, which is different from paper, so it cannot be exposed to water for a long period of time. Excellent adhesive strength when immersed in water.

The first characteristic effect of the method of the present invention is that when pasting a polyolefin resin film onto a wooden board, first a composite sheet is created by heat-sealing the nonwoven fabric and the film, and then the composite sheet is The most important point is to attach the sheet to the wooden board. In other words, commonly used adhesives can be used as is for adhesion to wood boards, and complete adhesion can be achieved at a much lower temperature than the heat-sealing method. The nonwoven fabric on the adhesive side serves as an escape route for water vapor generated from the wood board, so no bubble problems occur. The second characteristic effect is that by taking advantage of the above-mentioned characteristics, the overlay is completed at the same time as the wood board is completed by inserting the composite sheet during the manufacturing process of the wood board. As described above, according to the method of the present invention, repair of the surface of the wooden board can be omitted and it can be easily manufactured using an inexpensive adhesive, so that it is possible to provide a board for concrete formwork that is inexpensive and of excellent quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a method for manufacturing a composite sheet used in the present invention, and FIGS. 2 and 3 are cross-sectional views of an embodiment of a concrete form plate according to the present invention. DESCRIPTION OF SYMBOLS 1...Polyolefin-based spun H-effect film, 2...Nonwoven fabric, 3...Adhesive polyolefin copolymer resin, 5...
Pressure roll, 6... Pressure cooling roll, 7...
- Cooling roll, 8... Composite sheet, 9... Winding roll, 10... Wooden board, 11... Adhesive.

Claims (4)

[Claims] (1) A composite sheet is prepared by heat-sealing a nonwoven fabric to the lower surface of a film having an adhesive polyolefin copolymer resin layer under a polyolefin resin layer and impregnating the nonwoven fabric with the copolymer resin. A board for concrete formwork, which is attached to one or both sides of a wooden board through a nonwoven fabric layer, and the nonwoven fabric layer is impregnated with an adhesive. (2) A hot-melted adhesive polyolefin copolymer resin is supplied between the polyolefin resin film and the nonwoven fabric, and the adhesive resin is applied to the nonwoven fabric layer. A composite sheet is formed in which a nonwoven fabric is adhered to the lower surface of the resin based resin via an adhesive polyolefin copolymer resin, and the composite sheet and a wooden board are applied to the upper surface of the wooden board or the nonwoven fabric surface of the composite sheet. 1. A method for producing concrete formwork plates, which comprises polymerizing via a mold adhesive and bonding the same by hot or cold pressure at a temperature below the melting point of the resin constituting the composite sheet. (3) A hot-melted adhesive polyolefin copolymer resin is supplied between the polyolefin resin film and the nonwoven fabric, and the adhesive resin is applied to the nonwoven fabric layer to impregnate it into the nonwoven fabric layer. A composite sheet is formed in which a nonwoven fabric is adhered to the lower surface of the system resin via an adhesive polyolefin copolymer resin, and the composite sheet is placed at the top of a group of laminated veneers immediately before the deposition process in the plywood manufacturing process. Concrete characterized in that the composite sheet is bonded at the same time as the veneer by polymerizing with a thermosetting adhesive on the outside and heat-pressing this at a temperature that does not reach the melting point of the resin constituting the composite sheet. Method of manufacturing formwork boards. (4) A hot-melted adhesive polyolefin copolymer resin is supplied between the polyolefin resin film and the nonwoven fabric, and the adhesive resin is applied to the nonwoven fabric layer. A composite sheet is formed in which a nonwoven fabric is adhered to the lower surface of the system resin via an adhesive polyolefin copolymer resin, and the composite sheet is applied to a small piece layer after the forming process during the manufacturing process of particle board or wafer board. Polymerizes through a thermosetting adhesive applied to the nonwoven fabric layer of the composite sheet, and heat-presses this at a temperature that does not reach the melting point of the resin that makes up the composite sheet, bonding the composite sheet at the same time as particle board or wafer board is cured and molded. A method of manufacturing a board for concrete formwork, characterized by: