JPH06200618A - Manufacture of concrete panel - Google Patents

Abstract

PURPOSE:To promote durability by having polyolefin resin contain short fibers to form a resin sheet, and sticking the sheet on a wooden plywood. CONSTITUTION:Short fibers having 2mm-25mm of cut-length are mixed with polyolefin resin such as polypropylene, etc., at rate of 5%-60% to form a synthetic resin film sheet 2 have approximate 0.5mm-1.5mm in thrickness. The sheet 2 is stuck on a wooden plywood 1 having 11mm-13mm in thickness, applying liquid adhesive thereon and contacting a polyproylene sheet therewith by binding with cold-pressing. An adhesive film is put between the sheet and wooden plywood and is bound with hot-pressing, or adherence can be made by using an ultrasonic welder or high frequency welder.

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 a concrete panel product used in civil engineering construction work and the like.

[0002]

2. Description of the Related Art A concrete panel is used for driving concrete in civil engineering construction work, and the material thereof is exclusively made of wood plywood.

[0003]

Concrete panels are mainly used because wooden synthetic boards are manufactured at a low price, and concrete panels are widely used. There is a drawback that cement adheres to the surface and becomes unusable after repeated use, and it is then discarded by incineration or the like, which is a great use of Nanyo wood. By the way, the heavy use of South Sea timber has a direct impact on the destruction of nature, and the Ministry of International Trade and Industry strictly guides the import control from the viewpoint of global environment protection. There is.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and is characterized in that the cut length is approximately the same as that of a polyolefin-based resin having a far better releasability than wooden plywood. 5% of 2 mm to 25 mm organic short fibers
-60%, and the thickness is about 0.5 mm-1.
It is formed by adhering it to a wooden plywood in the form of a sheet of about 5 mm.

[0005]

[Function] A cut length of approximately 2 mm to 25 mm on the upper surface of plywood
By attaching a sheet of 0.5 mm to 1.5 mm polyolefin-based resin in which the organic short fibers mentioned above are mixed in a proportion of 5% to 60%, it has been difficult to use the conventional polyolefin-based resin and wood plywood. Adhesion was facilitated by mixing the above short fibers, and the durability such as boiling property was remarkably improved. In addition, by sticking it on the surface of the panel, it has excellent releasability from cement, it can be easily removed from concrete, there is no cement adherence, and the number of times of use is improved dramatically.

Further, mixing the short fibers into the polyolefin synthetic resin also has the effect of significantly reducing the tensile elongation of the polyolefin resin sheet. For example, in the case of a non-reinforced polyolefin synthetic resin sheet (polypropylene), the breaking elongation is 200%, but the sheet has
By incorporating cotton short fibers in a weight percentage of 0%, the elongation at break can be kept below 10%.
When used as a concrete panel, it not only improves the initial adhesiveness, but also greatly suppresses the swelling adhesion failure (including the failure during use) of the adhesive sheet.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings are sectional views of the products of the present invention. 1 is a wooden plywood, a conventional commercial product can be used as it is, but when used in the present invention, a thickness of 2-3 mm is prepared in advance.
It is made thin so that the overall wall thickness is finished 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.

2 is a polyolefin resin adhered to the upper surface of the above-mentioned wooden plywood, such as polypropylene and polyethylene, which is made of polypropylene having a high hardness and a high heat insulating property, and is a short fiber having a cut length of 8 mm. Polyester 65%, cotton 35% short fiber 30% to the above resin
% Mixed with a thickness of 1 mm was used.

The use of a polyolefin resin as the synthetic resin material in the present invention is because the polyolefin resin has excellent heat resistance such as boiling property 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 natural fibers and organic fibers is high.

The short fibers may be obtained by collecting various pieces of cloth discharged from a sewing factory and chopping them into a cut length of about 2 mm to 25 mm with a crusher. For example, it is useful as a measure against work waste, and the unit price can be reduced.

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 heat roll machine, or forming short fibers into a non-woven fabric and calendering the fibers The short fiber mixed sheet may be manufactured by a method of manufacturing a mixed sheet, or by separately sandwiching a nonwoven fabric between polypropylene double molten sheets and press-bonding them to integrally mold them.

When 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 applied and pressure-bonded by cold pressing. It may be pressed or adhered using an ultrasonic welder or a high-frequency welder. Also, when the polypropylene sheet is in a molten state at the stage of preparation, the adhesive film is pressure-bonded to the wooden plywood by the above hot press etc. You may. If the fibers are exposed by sanding the polypropylene sheet, the adhesive effect is further enhanced.

[0013]

The results of the performance test when a polyolefin sheet (polypropylene as an example) is used in the present invention are as follows.

[0014]

[Table 1]

Thus, polypropylene containing fibers is compared to polypropylene containing no fibers a. Improves elastic modulus and prevents sheet elongation. b. It has good heat resistance and does not cause creep (expansion due to thermal cycle, bulging or sinking and peeling from wood). c. The entire sheet is less affected by heat and shrinks less. d. Excellent response to temperature differences. e. It is suitable for hot pressing, especially at 100 ° C. or higher. As described above, by incorporating the short fibers in polypropylene, the required characteristics of the concrete panel can be realized.

[0016] Also, cutting with a saw or the like becomes easy, and nailing is easy without fear of cracking due to nailing. In particular, polypropylene is alkali resistant, has excellent releasability from concrete, the surface is finished smoothly, concrete panels are easily removed, and concrete pieces do not adhere even if used many times. However, it is the same as a new product, and polypropylene is a sheet with an appropriate thickness, and it has excellent heat resistance due to the mixture of short fibers, and it can be used for dozens of times if handled carefully so as not to damage the wooden part of the formwork. Endures. It can be used more than 10 times longer than the conventional wooden concrete panel which cannot be used after 3 to 4 times.

In the conventional example, in which a resin liquid is sprayed on the surface of a wooden concrete panel to improve the durability, a coating is thin and the durability of use is only improved at most about three times. On the other hand, Japanese Patent Application Laid-Open No. 2-3014051 discloses a method for producing a concrete panel by heat-fusing a polyolefin film and a non-woven fabric to form a composite film, and adhering the composite film to a wooden plywood. Although it is characterized in that it can be adhered to a wooden plywood by heat-sealing it with a polyolefin and leaving the lower surface of the nonwoven fabric as it is, the polyolefin has the disadvantage that a thin film must be used.

Further, this product requires a furnace for melting a polyolefin resin for adhering a composite film,
Further, a mechanical device for making a composite film is required. Therefore,
Although a double step of adhering 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 at the same time to manufacture the sheet integrally, which facilitates the manufacturing. Is.

That is, in this product, the non-adhesiveness of the polyolefin is improved by adhering it to the wooden plywood through the non-woven fabric, but in the present invention, the short fibers are adhered in the state where they are completely mixed in the sheet. The process cost is reduced by simplifying the process.

In the case of a polyolefin resin sheet containing no short fibers, the tensile strength is increased, the heat resistance is increased, the elongation is small with respect to the heat generated when the cement is solidified, and the durability is a major problem. A certain creep (peeling between the resin sheet and the wood part due to heat blister) does not occur, and the sheet has an appropriate thickness, and the durability is completely different. In the present invention, it is possible to use the concrete panel of the conventional wooden plywood more than 10 times the number of times of use, but at the cost of increasing the unit price by 20 to 30%,
It is very economically beneficial.

[Brief description of drawings]

FIG. 1 is a cross-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

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[Procedure amendment]

[Submission date] September 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Accordingly, polypropylene containing fibers is compared to polypropylene containing no fibers: a. Improves elastic modulus and prevents sheet elongation. b. It has good heat resistance and does not cause creep (peeling and bulging or shrinking due to heat cycle and peeling from wood). c. The entire sheet is less affected by heat and shrinks less. d. Excellent response to temperature differences. e. It is suitable for hot pressing, especially at 100 ° C or higher. As described above, by incorporating the short fibers in polypropylene, the required characteristics of the concrete panel can be realized.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

Compared to a polyolefin resin sheet containing no short fibers, the tensile strength is increased, the heat resistance is increased, the elongation is small with respect to the heat generated when the cement is solidified, and the durability problem is large. Creep (peeling from the resin sheet due to swelling due to heat), which is a problem, does not occur, and the sheet has an appropriate thickness, and the durability is completely different. In the present invention, a concrete panel made of conventional wooden plywood that can be used ten times or more than the number of times that it can be used can be manufactured at a cost of 20 to 30%, which is very economically advantageous.

Claims (2)

[Claims] 1. A polyolefin resin containing short fibers having a cut length of about 2 mm to 25 mm at a rate of 5% to 60% to prepare a resin sheet having a thickness of about 0.5 mm to 1.5 mm. The thickness of the sheet is about 11 mm to 13 mm
A method for manufacturing a concrete panel, characterized in that the concrete panel is pasted onto the wooden plywood. 2. The method for producing a concrete panel according to claim 1, wherein the short fibers are made of natural fibers and synthetic fibers, or a mixed fiber thereof.