JPH03224960A - paper cylindrical formwork - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a paper cylindrical form used for forming voids in concrete floors, concrete walls, etc. This invention relates to paper cylindrical formwork with improved durability and water resistance.

[Prior art and problems to be solved by the invention] Conventionally, paper cylindrical forms have been used to form voids in concrete floors or walls, but most of these are made of paraffin-treated waterproof board paper. Because it is manufactured by winding and gluing paper strips of waterproof paper in a spiral shape using vinyl acetate adhesive, cement mills seep into the concrete, making it easier to remove formwork from concrete than concrete. It may not peel off and damage the concrete surface, or paper may remain on the surface, making it impossible to obtain a clean concrete surface. For this reason, it has been proposed to form plastic-processed paper by winding it into a spiral shape, but such a formwork is not suitable for forming a formwork in which the overlapping edges are made of general-purpose vinyl acetate-based paper, which is used for ordinary paper. Since this type of adhesive does not bond well, moisture in the cement may seep into this area, reducing the strength of the formwork. In addition, moisture in the concrete seeps through the edges, lowering the compressive strength of the formwork itself, and the formwork may buckle during concrete pouring or curing, making it impossible to form a perfect circular void. be.

Furthermore, it has been proposed to wrap a plastic film around the outermost surface of the form body, but the commonly used vinyl acetate adhesive does not adhere well to the edges, causing the same problem as above. In addition, wrinkles may occur on the surface of the formwork during storage, and unevenness may occur on the surface of the poured concrete. It has also been proposed to cover the entire formwork body with a plastic film;
Although it has good peelability from concrete, the plastic film may wrinkle due to the heat generated during concrete pouring, making it impossible to obtain a smooth concrete surface.

The present invention was made in view of the above circumstances, and it is an object of the present invention to provide a paper cylindrical formwork that is excellent in water resistance and has improved peelability from concrete without significantly increasing manufacturing costs.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention has a cylindrical paper body in which several layers of paper strips are spirally wound and bonded, and the outermost circumferential surface or the innermost circumferential surface of the plastic-processed paper is arranged so that one edge side of the processed plastic paper overlaps each other. To provide a cylindrical paper formwork characterized in that it is spirally wound and coated, and the shaped part is adhered with a water-resistant adhesive.

[For production]

The paper cylindrical formwork of the present invention is constructed as described above,
Even when using plastic-processed paper, water-resistant adhesive is used on the edges to ensure strong adhesion.
In addition, the cement mill will not seep into the area (it will peel off easily from the concrete surface, and water from the concrete will be blocked by the plastic-treated paper during concrete pouring or curing, and will not penetrate into the formwork body. Therefore, an extremely good circular gap or cylindrical body can be formed without causing buckling of the formwork body or wrinkles of the plastic processed paper.

In addition, the use of water-resistant adhesive can be limited to the edges of the plastic-processed paper (where the plastic-processed papers are bonded together), and between the plastic-processed paper and the main body.
Since vinyl acetate adhesive, which is an inexpensive general-purpose adhesive, can be used, there is no significant increase in manufacturing costs.

Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

Fig. 1.2 shows an embodiment of the present invention, in which a formwork 1 consists of a cylindrical body 2 in which a paper band is spirally wound and bonded, and a plastic processed paper 3 is placed on the outermost surface of the cylinder 2 with a plastic layer 4 on the outside. It is formed by being spirally wound and coated so that the edge 5 thereof overlaps the edge 6 of the adjacent plastic processed paper. 7 is a water-resistant adhesive used for adhering this overlapping part. Specifically, water-resistant adhesives such as acrylic and rubber adhesives, hot melt adhesives, etc. are used. The adhesive 8 used for the other parts is a vinyl acetate-based general-purpose adhesive. Here, the filter paper band used in the present invention is not particularly limited, but may be waterproof board paper, paperboard, etc. with a thickness of about 0.3 to 1 mm, and the plastic processed paper used for the outermost surface is 10 mm thick.
Kraft paper laminated with a resin such as polyethylene, polypropylene, polyester, etc. of ~50 μm can be preferably used.

When pouring concrete using this formwork 1 to form a cylindrical void in a concrete floor or wall, this formwork 1
Concrete is placed in contact with the outer peripheral surface of the concrete. in this case,
Even if a large amount of moisture occurs on the surface of the poured concrete, the plastic layer 4 of the plastic-processed paper 3 will reliably block the moisture from reaching the cylinder 2, and the overlapping parts of the plastic-processed paper will have a water-resistant adhesive. Since it is firmly bonded with a compound, moisture will not seep in from this part, and therefore the cylinder body 2 will not absorb moisture and its strength will not decrease, allowing stable concrete placement. I can do it.

Next, after the poured concrete has hardened, the formwork l is removed from the surface of the poured concrete. In this case, since the concrete pouring surface of the formwork l is formed of the plastic layer 4, It can reliably prevent the concrete mill from seeping into the surface layer of the formwork and integrating the formwork and poured concrete during heating and curing. The formwork l can be easily and cleanly peeled off from the surface of poured concrete without leaving any residue behind.

Furthermore, in this formwork 1, the use of an expensive water-resistant adhesive is limited to bonding between the edges 5 and 6 of the plastic processed paper 3, and the use of an inexpensive waterproof adhesive is limited to bonding between the plastic processed paper 3 and the cylinder body 2. Since a vinyl acetate-based adhesive is used, the above performance can be obtained without significantly increasing costs.

FIG. 3 shows another embodiment of the present invention, in which a mold l according to this embodiment has a plastic processed paper 3 on the innermost circumferential surface of a cylindrical body 2 in which a paper band is spirally wound and bonded. It is formed by spirally wrapping the plastic layer 4 on the inside so that its edge 5 overlaps the edge 6 of the adjacent plastic processed paper. This formwork l is used to fill the internal hollow part with concrete to form a cylindrical body, and the other configurations and effects are the same as the embodiment shown in Fig. 1.2. , the explanation thereof will be omitted.

Note that the paper cylindrical form frame of the present invention is not limited to the above embodiments, and various changes may be made without departing from the gist of the present invention.

〔Effect of the invention〕

As explained above, the paper cylindrical formwork of the present invention has excellent releasability, and when the formwork is removed from the concrete surface after the concrete has hardened, it does not damage the concrete surface or leave formwork fragments. The formwork can be easily and cleanly peeled off from the concrete surface without any problems. In addition, since it has excellent water resistance, the strength of the poured concrete does not decrease due to moisture (so that concrete can be poured stably).

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a paper cylindrical form according to an embodiment of the present invention, Fig. 2 is a partially enlarged sectional view of the form, and Fig. 3 is a sectional view showing another embodiment of the invention. FIG. l...Paper cylindrical formwork 2...Paper cylindrical body 3
...Plastic processed paper 7...Water resistant adhesive? −
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Claims (1)

[Claims] 1. Cover the outermost or innermost circumferential surface of a cylindrical paper body made by winding and bonding several layers of paper strips in a spiral shape, and wrapping the plastic processed paper in a spiral shape so that one edge side overlaps each other. A paper cylindrical form, characterized in that the overlapping portions are adhered with a water-resistant adhesive.