JPH11200619A - Manufacture of panel for concrete form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel for a concrete form repeatingly usable for a concrete in a well-separative manner without separation between a polyolefin based resin film and a wood plate in long-time use. SOLUTION: In a manufacture of a panel 3 for a concrete form by adhering a plastic film to the surface of a wood plate, polyolefin based resin film formed with hot-melt adhesive applied to the upper face of the wood plate is temporarily adhered thereto with a flat press machine and then the upper face of the wood plate and the side faces (the butt ends) on four peripheries are adhered thereto with a vacuum press machine. In this case, the hot-melt adhesive preferably contains 70-95 wt.% a olefin copolymer and 5-30 wt.% adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a durable concrete formwork panel having good adhesion of a polyolefin resin film, good releasability of concrete, and reusability.

[0002]

2. Description of the Related Art When constructing a concrete structure by pouring concrete at a construction site or the like, a wooden board such as plywood has been used as a form since ancient times. In the case of large buildings, metal plates and plastic plates have come to be used in place of wooden plates.However, the characteristics of lightweight and inexpensive wooden plates are preferred. Is widely used. However, when a wood board is used as a panel for a concrete formwork, there is a problem that the wood board has poor peelability of hardened concrete. In particular, when the size of the wooden board is increased as in recent years, this is a bigger problem. Due to poor releasability, the surface condition of the wooden board becomes rough and defective in a single use, and breakage occurs at the time of release from the mold, so that repeated use is restricted, and as a result, the cost of the mold is high. When a wooden board was used, the surface of the concrete in contact with it was poor in smoothness.

[0003] In order to remedy such drawbacks of the wood board, attempts have been made to use the wood board surface coated with a plastic film or sheet. Various types of plastic films, such as polyolefin, polyamide, polyester, polyvinyl chloride, and polyurethane, have been tried, but they are inexpensive, have good releasability from concrete, and are resistant to alkali of cement. A film of a polyolefin resin is most suitable as having a property of being resistant and having high strength.

[0004] An adhesive is used to attach the polyolefin resin film or sheet to the surface of a wooden board. There are various solvent-based and water-based liquid adhesives, and those having excellent adhesive strength can be selected according to the type of plastic film. However, when a liquid adhesive is used, there are many disadvantages to industrial production because a long time is required for drying, a large drying apparatus is required, and in the case of a solvent, a recovery process is required. In order to avoid this, several methods using a hot-melt adhesive as an adhesive have been disclosed.

Japanese Patent Application Laid-Open No. 50-44626 discloses a technique for bonding a synthetic resin film or sheet such as medium or low pressure polyethylene or vinyl chloride to the surface of a plywood using a hot melt adhesive mainly composed of a thermoplastic synthetic resin. Is disclosed. The hot melt adhesive used here is mainly composed of polyamide, polyester, ethylene-vinyl acetate copolymer (EVA), polyethylene, and polypropylene, and if necessary, additives such as a tackifying resin are compounded. I have. Japanese Patent Publication No. 63-11984 discloses a technique of overlaying a synthetic resin sheet on the surface of a plate material such as plywood via an adhesive obtained by mixing a thermosetting resin adhesive and a hot melt adhesive. Urea resin, urea melamine resin, phenol resin, etc. are used as thermosetting resin adhesives, and ethylene-vinyl acetate copolymer resin (EVA), polyethylene resin, polypropylene resin, polyamide resin, etc. are used as hot melt type adhesives. It discloses a polymer in which a tackifier such as a rosin-based resin or a terpene resin, a wax or the like is added. Japanese Patent Application Laid-Open No. Hei 6-88425 discloses that a surface of a wooden concrete form substrate and one end of a four-way edge are covered with a plastic film, but a hot-melt adhesive is used for laminating a film of polyethylene, polypropylene, polyester or the like on the substrate. It mentions using an adhesive such as.

However, when a plastic film is bonded to a mold made of another material such as wood or metal with a hot melt adhesive as described above, it is a reality that sufficient bonding durability is not actually obtained. . In particular, a conventional hot melt adhesive was not sufficient for a plastic film to satisfactorily adhere a polyolefin resin film such as polypropylene or poleretin to a concrete form made of these materials. That is, there was a problem in water resistance and weather resistance as well as the initial adhesive strength. Since concrete formwork is generally used outdoors, this problem has led to the delamination of the plastic film layer.
In addition, the conventional plastic film adhesive product had to be discarded if the plastic film on the surface was peeled, scratched, torn, or stained while being used several times. .

On the other hand, as a conventional method of bonding a plastic film to a wooden board, a roll press machine or a flat press machine is often used. Since only the upper surface of the film was bonded, it was peeled off after several uses and was unusable. In addition to these two methods,
There is a vacuum press machine. In this method, the upper surface of the wooden board is
A plastic film can be adhered to the side (kiguchi) of the circumference, but in a large area such as a wooden plate for concrete formwork, air enters between the wooden plate and the plastic film and the adhesion cannot be completely performed.

[0008]

DISCLOSURE OF THE INVENTION The present invention has no peeling between a plastic film and a concrete form substrate, especially a wooden substrate over a long period of use, has good releasability from concrete, can be used repeatedly, and has good design. Yes,
Another object of the present invention is to provide a panel for concrete formwork in which an environmentally friendly plastic film is adhered and laminated. Further, the present invention replaces the plastic film on the surface with a new one when the surface is damaged. An object of the present invention is to provide a concrete formwork panel which can be used.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been accomplished as a result of intensive studies to obtain a concrete formwork panel free of the above-mentioned drawbacks. That is, the present invention relates to a method of manufacturing a concrete form panel by bonding a plastic film to the surface of a wooden board, and first, using a flat plate press, a polyolefin-based resin in which a hot melt adhesive is applied to the upper surface of the wooden board. A method for producing a panel for a concrete formwork, comprising temporarily bonding a film and then bonding the upper surface and four side surfaces (a wooden edge) of the wooden board using a vacuum press machine.

In the present invention, a polyolefin-based resin film is stuck on a wooden board to form a panel for concrete formwork. However, by using a film of polypropylene, polyethylene, or the like as the polyolefin-based resin film, it is possible to adhere concrete. Therefore, a characteristic that a stripper is not required, a beautiful concrete surface can be obtained, and a harmful gas such as a PVC plate is not generated at the time of disposal and the environment is good. Further, the advantages of using the hot melt adhesive of the present invention are as follows. That is, (1) the adhesive strength is large, (2) the weather resistance and light resistance are excellent, and (3) even when the polypropylene film is damaged, the operation of peeling the damaged film and replacing the new film is easy. (That is, the polyolefin resin film can be easily peeled off by heating the concrete panel to melt the hot melt adhesive).

In the concrete formwork panel of the present invention, the polyolefin resin film to be adhered to the surface of the plate-shaped material may be either an inflation film or a cast film, and a normal commercial product can be used as it is. . Polyethylene may be polymerized by low-pressure method, medium-pressure method or high-pressure method, and polypropylene may be a copolymerized polypropylene obtained by copolymerizing ethylene, butene, or a blended polypropylene obtained by blending an atactic polymer, polybutene, or the like. Good. In some cases, a polyolefin-based resin film to which an ultraviolet absorber, an antioxidant, a coloring agent, or the like is added is more preferable. Polyolefin resin film may be used by activating the surface by corona discharge treatment or the like,
This is not necessary in the case of the present invention. If the thickness of the polyolefin-based resin film is about 10 μm or more, the object can be sufficiently achieved, and preferably 30 to 300 μm, more preferably 50 to 200 μm.

Since the polyolefin-based resin film has little adhesion of concrete, it does not require a peeling agent, and a beautiful concrete surface can be obtained. In addition, when discarded, no harmful gas such as a PVC plate is generated, which is good for the environment. In the present invention, a hot-melt adhesive is used as the adhesive, and the hot-melt adhesive mainly contains an α-olefin copolymer and a tackifier. The α-olefin copolymer is a copolymer composed of two or more kinds of α-olefin monomers, and a small amount of other copolymerizable monomers can be copolymerized with the α-olefin copolymer if necessary. α-olefins include ethylene, propylene, pentene-1,4-
Methylpentene-1, butene-1, hexene-1, octene-1, decene-1, dodecene-1 are included. Propylene, ethylene, pentene-1, 4-methylpentene-1, butene-1, and hexene-1 are preferred. Particularly preferred is a copolymer composed of propylene, ethylene and butene-1. Examples of the monomer copolymerizable with the α-olefin that can be used together with the α-olefin include a vinyl ester of a saturated carboxylic acid, an unsaturated carboxylic acid, and an alkyl ester of an unsaturated carboxylic acid. In addition, you may add the homopolymer of (alpha) -olefin, for example, polyethylene, polypropylene, polybutene, etc.

The tackifier used in the present invention is preferably a saturated petroleum resin such as an aliphatic hydrocarbon, a cycloaliphatic hydrocarbon, or a hydrogenated petroleum resin. These are commercially available as commercial products, for example, Archon (manufactured by Arakawa Chemical Co., Ltd.), Escolets (manufactured by Tonex Corporation), FIR-600 (manufactured by Mitsui Petrochemical Co., Ltd.) and the like can be used. As the tackifier, rosin and its derivatives, terpene resins, and the like can be added as necessary, in addition to the saturated petroleum resin.

The α-olefin copolymer and the tackifier in the hot melt adhesive composition are 70 to 95% by weight and 5% by weight.
-30% by weight, preferably 75-90% by weight and 10-2
5% by weight, more preferably 80-90% by weight and 10-2
It is blended at a ratio of 0% by weight. If the amount of the α-olefin copolymer is less than 70% by weight, the proportion of the tackifier increases, the tackiness increases, the handling becomes difficult, and the bonding strength after bonding decreases. If the proportion of the α-olefin copolymer is more than 95% by weight, the adhesion to the plate tends to decrease.

The hot-melt adhesive composition may further contain a lubricant or a cold-resistant agent in order to adjust the adhesive properties and other properties. As the lubricant, wax such as paraffin wax, microcrystalline wax, low molecular weight polyethylene wax, Fischer-Tropsch wax, modified wax, and metal soap such as calcium stearate and zinc stearate can be used.
Synthetic rubbers such as polyisobutylene, butyl rubber, and styrene butadiene rubber can be used as the cold-resistant agent. Further, an antioxidant, a filler, a plasticizer, a special oligomer, and the like can be added to the adhesive as other additives.

The amount of the hot-melt adhesive to be used varies to some extent depending on the condition of the surface of the wooden board to be bonded. In the case of bonding the polyolefin resin film to the wooden board, the thickness is about 10 μm to 300 μm, preferably 30 to 200 μm. used. Vicat of the hot melt adhesive of the present invention
Softening temperature is 50 to 150 ° C, preferably 60 to 120 ° C
It is. When the softening temperature is lower than 50 ° C., the adhesive is softened and easily peeled off when overheated by solar heat or the like during use as a concrete form panel. The softening temperature is 15
If the temperature is higher than 0 ° C., a high temperature is required for the bonding process, which may cause a trouble such as warpage of the mold in addition to damaging the polyolefin-based resin film and wasteful energy consumption.

The melt viscosity M of the hot melt adhesive of the present invention
FR (190 ° C) is 0.5 to 100, preferably 1 to 5
Desirably, it is 0. This hot melt adhesive has a large adhesive strength between the polypropylene film and the wooden board and is water resistant,
In addition to good alkali resistance, weather resistance, light resistance, and the like, when the polypropylene film is damaged by use, there is an advantage that the operation of peeling the polypropylene film and replacing it with a new one is easy.

The production of the concrete formwork panel of the present invention is generally carried out by applying a hot-melt adhesive to a polyolefin resin film, laminating the adhesive-coated film on a wooden board, thermocompression bonding of the laminate, and cooling. Is performed along the steps of When laminating the adhesive-coated film and the wooden board, it is preferable to use a continuous long film that has been coated with an adhesive in advance, cooled and wound into a roll, for example. It is also possible to adopt a method in which the hot melt adhesive is applied to the wooden board or to both the polyolefin resin film and the wooden board. The hot melt adhesive can be applied by using a roll coater, a die coater, or the like, which has been used for a conventional hot melt adhesive.

As the substrate of the concrete formwork panel of the present invention, any of the materials conventionally used as concrete formwork can be applied, but it is lightweight, easy to process, easy to assemble on site, and inexpensive. A wood board is preferred in terms of low height and the like. Examples of the wood board include plywood, particle board, and hard board. However, not only concrete formwork panels with wooden boards as substrates,
Metal, FRP, or the like can be used as the substrate.

The adhesion of the polyolefin resin film to the wooden board is not sufficient when used only on the upper surface of the wooden board, and it is necessary to adhere the polyolefin resin film also to the four side surfaces (kiguchi). In the present invention, a flat plate press and a vacuum press are used to bond the polyolefin resin film to the upper surface of the wooden board and the four sides (kiguchi), but the flat plate press uses the upper surface of the wooden board and the polyolefin resin film. The air between them is removed and temporary bonding is performed, and then, the main bonding of the upper surface and the bonding of the four side surfaces (kiguchi) are performed by a vacuum press machine.
The panel for concrete formwork manufactured in this way has high durability and can be used repeatedly 10 times or more.
When the polyolefin-based resin film-coated concrete formwork panel is damaged or damaged due to use and can no longer be used, peel off the polyolefin-based resin film and attach a new polyolefin-based resin film to the surface of the wooden board. , Can also be used.

[0021]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a perspective view of a propylene film temporarily bonded to the upper surface of a wooden board by a flat press machine, and FIG. 2 is a concrete form panel in which the upper surface and four side surfaces (kiguchi) are further bonded by a vacuum press machine. It is a perspective view of. The following hot melt adhesive formulations were melt blended with an extruder pelletizer to form pellets. (1) 65 parts by weight of ethylene-α-olefin copolymer (density 0.88 g / cm ³ , Vicat softening point 60 ° C, MFR (190 ° C) 3.8) (2) Saturated petroleum resin (softening point 115 ° C) 35 parts by weight (3) Lubricant (fatty acid amide) 0.1 part by weight

[0022] The obtained pellets are extruded to a thickness of 8
It was extruded onto a 100 μm thick polypropylene film in the form of a 0 μm film to prepare a hot melt adhesive laminated polypropylene film. This hot melt adhesive laminated polypropylene film is laminated on the wooden board so that the adhesive side is in contact with the wooden board, and the upper surface is temporarily bonded at 110 ° C., 2 kgf / cm ² for 10 seconds by a flat plate press, Next, at 125 ° C. in a vacuum press machine, 2.
The top surface and the four side surfaces (kiguchi) were adhered to each other under the conditions of 5 kgf / cm ² and 25 seconds to prepare a polypropylene film-coated concrete form panel.

On the other hand, for comparison, hot-melt adhesive was used in the same manner as described above, except that a commercially available EVA-based hot-melt adhesive (trade name “Kranbetter” manufactured by Kurashiki Spinning Co., Ltd.) was used as the hot-melt adhesive. A hot-melt adhesive-laminated propylene film is prepared by laminating the hot-melt adhesive-laminated propylene film on a wooden board so that the adhesive side is in contact with the wooden board.
° C., adhered under the conditions of 2.5 kgf / cm ^2, 25 seconds, to produce a panel for polypropylene film coated concrete formwork.

The concrete formwork panels prepared in Examples and Comparative Examples, and unprocessed wood boards not laminated with a polypropylene film were pneumatically evaluated by the following evaluation methods, adhesive strength, weather resistance, concrete adhesion, And the number of usable times was evaluated. [Evaluation method] (1) Air biting: Air is input between the wooden board and the hot melt adhesive, and the state in which the polypropylene film is floating is visually observed. (2) Adhesive strength: A 1-inch wide test piece was prepared from a polypropylene film-coated concrete formwork panel, and the adhesive strength was measured at a peel angle of 180 °. (3) Weathering resistance: The polypropylene film-coated concrete formwork panel was exposed outdoors, and the state of peeling was observed over time.

(4) Releasability from Concrete Surface The state of adhesion of concrete to the formwork surface after use twice was evaluated by visual observation. (5) Number of Uses The number of uses until the polypropylene film becomes practically unusable due to peeling of the polypropylene film, breakage or warpage of the mold itself, or adhesion of concrete to the mold surface. The evaluation results are shown in Table 1.

[0026]

[Table 1] a): Reduced number of usable times due to film peeling

[0027]

Industrial Applicability The polyolefin resin film-coated concrete formwork panel of the present invention has a higher adhesive strength than a conventional wood board laminated with a plastic film using a hot-melt adhesive or a solvent-based adhesive. In addition, it has excellent durability, has good mold release properties from concrete, has good design, can be used repeatedly, and improves the adhesion of various finishing materials to the concrete surface. This has a great effect that the material can be prevented from peeling and falling.

[Brief description of the drawings]

FIG. 1 is a perspective view of a hot-melt adhesive-applied polypropylene film temporarily bonded to an upper surface of a wooden board by a flat plate press.

FIG. 2 is a perspective view of a concrete formwork panel obtained by temporarily bonding a polypropylene film coated with a hot-melt adhesive to the wood board of FIG. 1 and bonding the upper surface and four sides (kiguchi) to each other by a vacuum press machine. is there.

[Brief description of reference numerals]

 1 Wood board 2 Hot melt adhesive coated polypropylene film 3 Concrete formwork panel

Claims (2)

[Claims] 1. A method for manufacturing a concrete formwork panel by bonding a plastic film to a surface of a wooden board, wherein a polyolefin resin having a hot melt adhesive applied to an upper surface of the wooden board using a flat plate press. After the film is temporarily bonded, the upper surface and the four side surfaces (kiguchi) of the wood board to which the polyolefin resin film is temporarily bonded are bonded using a vacuum press machine. Production method. 2. The hot-melt adhesive comprises 70 to 95% by weight of an α-olefin copolymer and 5 to 30% by weight of an adhesion promoter, and the α-olefin copolymer is ethylene as one of the constituent monomer components. The concrete formwork panel according to claim 1 or 2, wherein the tackifier is a saturated petroleum resin.