JP2622652B2 - Method of manufacturing concrete panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing concrete panel products used in civil engineering construction work and the like.

[0002]

2. Description of the Related Art In civil engineering construction work, concrete panels are used for pouring concrete, and these materials are made exclusively of wooden plywood.

[0003]

Concrete panels are mainly used and often used because wooden composite boards are manufactured at a low cost, but such concrete panel products are 3-4. There is a drawback that the cement adheres to the surface and becomes unusable after repeated use, and after that, it is disposed of by incineration or the like. By the way, the heavy use of South Sea lumber is directly linked to the destruction of nature, and the Ministry of International Trade and Industry has strictly guided import control in terms of global environmental protection, and it has become a problem that further improvement in durability is required. I have.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is characterized by the fact that the cut length is approximately equal to that of a polyolefin resin which is much more releasable than wooden plywood. 5% of organic short fibers of 2mm to 25mm
６０60%, and the thickness is approximately 0.5 mm〜1.
It is configured as a sheet having a size of about 5 mm and attached to a wooden plywood.

[0005]

[Function] On the plywood upper surface, cut length is about 2mm ~ 25mm
By adhering a sheet of polyolefin resin of 0.5 mm to 1.5 mm in which the obtained organic short fibers are mixed at a ratio of 5% to 60%, a polyolefin resin and a wooden plywood, which were conventionally difficult, are attached. Adhesion became easier by mixing the above-mentioned short fibers, and durability such as boiling property was remarkably improved. By sticking to the surface of the panel, it is excellent in releasability from cement, can be easily removed from concrete, does not adhere to cement, and the number of times of use is remarkably improved.

Further, by mixing short fibers into the polyolefin-based synthetic resin, there is also an effect that the tensile elongation of the polyolefin-based resin sheet is significantly reduced. For example, in the case of a non-reinforced polyolefin-based synthetic resin sheet (polypropylene), it exhibits a breaking elongation of 200%.
By mixing short cotton fibers at a weight percentage of 0%, the elongation at break can be suppressed to 10% or less.
This greatly reduces poor adhesion (including defects during use) due to swelling of the adhesive sheet when used as a concrete panel.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a product according to the present invention. 1 is a wooden plywood, and a conventional commercially available product can be used as it is, but when it is used in the present invention, the thickness is 2-3 mm in advance.
The thickness is made as thin as possible so that the overall thickness is in the range of about 11 mm to 13 mm. At this time, the vertical and horizontal dimensions are conventional standard dimensions, but special dimensions may be designed.

Reference numeral 2 denotes a polyolefin resin adhered to the upper surface of the wooden plywood, which is made of polypropylene, polyethylene, or the like. 30 fibers of 65% polyether and 35% cotton in the above resin
% Was used.

The reason for using a polyolefin-based synthetic resin material in the present invention is that the polyolefin-based material has excellent heat resistance such as boiling properties and can be obtained at a low cost. The short fibers may be organic fibers such as natural fibers, synthetic fibers, and wood chips. It is preferable that the mixing ratio of the natural fiber and the organic fiber is higher.

[0010] The short fiber may be obtained by collecting various pieces of cloth discharged from a sewing factory and chopping it with a crusher into a cut length of about 2 mm to 25 mm. This is useful as a countermeasure for work waste and can reduce the unit price.

As a method of mixing short fibers, a method of kneading polypropylene and short fibers into a sheet by using a twin-screw kneading extruder or a hot roll machine, or forming a short fiber into a nonwoven fabric, and using a calender or the like A short fiber mixed sheet may be manufactured by a method of manufacturing a mixed sheet, or by separately pressing a non-woven fabric between two double melted sheets of polypropylene and pressing them integrally.

In bonding the polypropylene sheet and the wooden plywood, a liquid adhesive was applied to the entire upper surface of the wooden plywood, and the polypropylene sheet was abutted and pressed by cold pressing. Or using an ultrasonic welder or a high-frequency welder, and bonding the adhesive film in the molten state at the stage of preparing the polypropylene sheet to a wooden plywood by hot pressing as described above. May be. If the fibers are exposed by sanding the polypropylene sheet, the initial adhesiveness is improved and the adhesive effect is further increased.

[0013]

The results of performance tests using a polyolefin sheet (eg, polypropylene) according to the present invention are as follows.

[0014]

[Table 1]

Thus, the fiber-containing polypropylene has the following advantages: a. The elastic modulus is improved, and the elongation of the sheet is prevented. b. Good heat resistance and no creep (stretching and shrinking due to thermal cycling and peeling off from wood). c. The entire sheet is less affected by heat and shrinks less. d. Excellent response to temperature differences. e. Hot pressing is particularly preferable when the temperature is 100 ° C. or higher. As described above, when the short fibers are contained in the polypropylene, the required characteristics of the concrete panel can be realized.

In addition, cutting with a saw or the like is easy, and nailing is easy without fear of cracking due to nailing. In particular, polypropylene is alkali-resistant, has excellent mold release properties from concrete, has a smooth surface, is easy to remove concrete panels, does not adhere to concrete pieces no matter how many times it is used, and is used 20 times per time. However, it is the same as a new one, and polypropylene is a sheet of moderate thickness, has excellent heat resistance by mixing short fibers, and can be used several tens of times if handled carefully so as not to damage the wooden part of the formwork To withstand. 10 times or more of durable use can be realized as compared with a wooden concrete panel which cannot be used after three to four times of conventional use.

In the conventional example, when a film is formed by spraying a resin liquid on the surface of a wooden concrete panel to improve the durability, the film is thin and the use durability is improved only about three times at most. On the other hand, Japanese Patent Application Laid-Open No. Hei 2-3014051 discloses a method in which a polyolefin film and a nonwoven fabric are heat-fused to produce a composite film, which is bonded to a wooden plywood to produce a concrete panel. Although it is characterized in that it is heat-fused with a polyolefin and the lower surface of the nonwoven fabric is left as a nonwoven fabric to enable adhesion to a wooden plywood, the polyolefin has a drawback that a thin film must be used.

Furthermore, this requires a furnace for melting a polyolefin-based resin for producing a composite film and bonding,
Also, a mechanical device for producing a composite film is required. Therefore,
Although a double step of bonding the composite film and the wooden plywood is required, in the present invention, for example, in the process of manufacturing a polyolefin resin sheet, fibers can be mixed simultaneously and the sheet can be manufactured integrally, so that manufacturing is easy. It is.

That is, in this method, the non-adhesiveness of polyolefin is improved by bonding it to a wooden plywood via a nonwoven fabric. However, the present invention relates to a method in which short fibers are completely mixed in a sheet. And the process cost is reduced by simplifying the process.

In the case of a polyolefin resin sheet mixed with short fibers, the tensile strength is increased, the heat resistance is increased, the elongation is small with respect to the heat generated during the solidification of cement, and the durability is a major problem. There because click rape (peeling between the resin sheet and the wood in swelling due to heat) does not occur,
In addition, the sheet has a moderate thickness, and the durability is completely different. In the present invention, one that can be used more than 10 times the number of times of using a conventional wooden plywood concrete panel,
The cost can be increased by 20 to 30%, which is very economically advantageous.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view of a product manufactured by the product of the present invention.

[Explanation of symbols]

 1 Wooden plywood 2 Synthetic resin film sheet

Claims (4)

(57) [Claims] 1. A polyolefin resin pellet and a short fiber having a cut length of about 2 mm to 25 mm are heated and kneaded at a ratio of 5% to 60% using a twin-screw kneading extruder to a thickness of about 0.5 mm to about 0.5 mm. A method for producing a concrete panel, comprising: preparing a resin sheet of about 1.5 mm, and attaching the sheet to a wooden plywood having a thickness of about 11 mm to 13 mm with an adhesive . 2. The physical properties of the resin sheet are as follows: tensile elongation at break.
(%) 5 to 45, molding shrinkage (%) 0.5 to 1
The concrete panel according to claim 1, wherein
Manufacturing method . 3. In bonding a resin sheet and a wooden plywood,
3. The method for manufacturing a concrete panel according to claim 1, wherein a liquid adhesive is applied to the entire upper surface of the wooden plywood, and the resin sheet is brought into contact with the upper surface and pressed by a cold press. 4. A contact surface of a resin sheet with a wooden plywood.
Sanding treatment to make the short fibers exposed on the entire contact surface
4. The method according to claim 1, wherein said step is performed.
Method of manufacturing concrete panels .