JPH0245378Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is used for concrete peeling as a mold release material attached to the concrete contact surface of concrete pouring formwork or sheathing boards used in the construction of concrete buildings, for example. Regarding the seat.

Conventional technology and its problems Conventionally, for example, construction of columns, beams, walls, floors, stairs, etc. of reinforced or steel-framed concrete buildings, or construction of foundations, waist walls, underground beams, etc. of steel-framed or unreinforced concrete buildings, etc. As is well known, concrete construction is carried out by temporarily constructing formwork made of wood, metal, etc. Recently, plywood has been commonly used as such a formwork, especially as a weir plate, and a so-called veneer temporary frame is used, in which plywood is used as a panel and attached to batten material. However, when constructing a concrete building using such wooden formwork, the following problems inevitably arise.

In other words, during concrete pouring, concrete may seep into the water-absorbing wooden formwork and be lost, misalignment of the surface of the weir plates at joints, differences in the quality of the sheath plates, number of uses, etc. Due to differences in surface conditions, incomplete fusion of cement paste, sand, and gravel, irregularities, or many uneven bubbles and color may occur on the concrete-constructed surface, that is, the so-called bare bare surface. In most cases, a considerable amount of concrete is damaged, resulting in many defective areas such as missing concrete parts (so-called junks) where gravel is exposed, especially at the external and internal corners of columns and beams, and the finish is not in good condition. Repairs or finishing work had to be carried out.

Furthermore, the removal of formwork from concrete,
It is actually quite difficult to remove the formwork because of the adhesive parts between the two, and the weir plates are often damaged when removing the formwork.Even if you handle it carefully, the temporary plywood frame can only be used three times at most. However, the disadvantage was that the cost of formwork materials increased somewhat.

To address this drawback, a proposal has been made in the past to bond a synthetic resin plate-shaped body to one side of the formwork in advance in order to facilitate the peeling of the formwork from the concrete (Japanese Patent Publication No. 52-27646). ,in this case,
Not only is it impossible to prevent cement paste from leaking out from the joints of the formwork, but it also creates unevenness, or so-called mismatch, between adjacent weir plates, resulting in the same drawbacks as the conventional method described above. It was hot. On the other hand, there has also been a proposal to completely lay a synthetic resin film or sheet as a mold release material on the inner surface of the formwork (Special Publications Publication No. 48).
-38184), but it is not only difficult to actually lay it in a stretched state on the inner surface of the formwork on site, but even after concrete is poured, a film or sheet based on the heat generated by the concrete during the curing period. Due to its thermal expansion, it wrinkles and digs into the concrete frame, and after the formwork is removed, a portion of the film is torn and remains on the concrete frame, which is an inconvenience.

On the other hand, it is used for holes for anchor bolts provided in the foundations of concrete buildings, foundations for equipment installation, etc., or for forming openings such as through holes in ceilings, walls, floors, beams, etc. The formation of holes and other openings in concrete buildings, such as formwork, is mainly done by using embedded formwork, which is formed into a cylindrical shape with a bottom, using a frame material such as plywood, and this is used directly as a formwork for forming concrete foundations, etc. After positioning and inserting and fixing the formwork inside, concrete for the foundation is poured, and after it solidifies, the embedded formwork is damaged and removed using tools such as a crowbar, nail puller, or chisel. I was getting used to it. However, the formation of such openings requires a great deal of labor and time, including the removal of the embedded formwork.
In other words, the formwork is firmly fixed under the lateral pressure of the concrete poured around it.
Moreover, since it is strongly adhered to the concrete surface, in order to remove it, the formwork must be struck or pried with a crowbar or other tools to separate it from the concrete surface, and the formwork must be destroyed and removed. It was a hassle. Furthermore, the impact applied when removing the formwork may cause damage or cracks to the surrounding concrete, reducing the strength of the concrete, and the top edge of the concrete foundation may be damaged when the formwork is removed. In order to complete the construction, it was necessary to level the top with mortar after installing anchor bolts, etc. In addition to the above, synthetic resin pipes such as vinyl chloride pipes, metal pipes, wooden or metal rods, etc. may also be used as molds for forming such openings, but in any case, Removal work is extremely difficult and troublesome due to adhesion to concrete, and has almost the same problems as described above.

In order to solve the above-mentioned problems all at once, the applicant of the present application has published the previous application of Japanese Patent Application Laid-Open No. 55-111562 and Utility Model Application No. 58-19051, in which the inner surface of the formwork for concrete pouring or the opening We proposed that the outer surface of the part of the forming concrete formwork to be buried in concrete be coated with a closed-cell foamed polyethylene sheet as a concrete release material. With this proposal, it is possible to easily attach the work to the formwork, and it does not cause wrinkles or tears, and it is possible to achieve extremely good mold releasability from concrete, as described above. Although a concrete mold release material with excellent practicality that can solve various problems at once was obtained, it was found that, on the other hand, it still had the following drawbacks. That is, the above-mentioned sheet has a pressure-sensitive adhesive layer previously provided on the back surface of the sheet so that it can be easily attached to the formwork at the concrete pouring site. It was provided as a product covered and protected with release paper. For this reason, in the above-mentioned pasting work, the release paper had to be removed and pasted onto the formwork at the concrete pouring site, which was not only a little troublesome, but also caused the paper to be removed from the sheet. There was an inconvenience that the release paper had to be disposed of because it was no longer needed. Furthermore, since the sheet is made of foamed polyethylene, its tensile strength is relatively low, especially when it is thin, and when the used sheet is peeled off from the formwork, the sheet is There was also the inconvenience that it would tear and a part of it would remain attached to the formwork.

In order to solve the above-mentioned problems, this invention proposes a concrete peeling sheet that is a further improvement on the above-mentioned invention and invention related to the applicant's previous application.

That is, this invention uses a foamed synthetic resin sheet as the sheet material in order to facilitate the pasting process and prevent wrinkles and tears, as well as a polyethylene film laminated to the sheet. If this film is used, it is possible to improve the tensile strength while maintaining good releasability to concrete.Moreover, if the film is provided with fine irregularities by embossing, It was discovered that the product could be provided as a roll without the need for release paper, and the problems described above could be solved all at once, and the product was completed based on this knowledge.

Means to Solve the Problems This invention is based on a flexible foamed synthetic resin sheet body 1 with a thickness of 1 to 5 mm, on one side of which a high-pressure polyethylene film 2 is provided with fine irregularities 2a by embossing. Along with being laminated and integrated,
The gist of the present invention is a concrete peeling sheet characterized in that a pressure-sensitive adhesive layer 3 is applied and formed on the other surface of the sheet body 1.

Embodiments Hereinafter, this invention will be explained based on illustrated embodiments.

As shown in FIGS. 1 and 2, the concrete peeling sheet A of the embodiment of this invention has a high-pressure polyethylene film 2 laminated and integrated on one side of a flexible foamed synthetic resin sheet body 1. , a pressure-sensitive adhesive layer 3 is applied and formed on the other side of the sheet body 1, and is provided in the form of a roll.

The material of the foamed synthetic resin sheet body 1 is not particularly limited as long as it is flexible;
More preferably, it is non-hygroscopic, has good thermal stability, little thermal expansion and contraction, has excellent weather resistance, is easy to cut, and is as inexpensive and lightweight as possible.
Moreover, it is preferable that the adhesive has suitable tension resistance and cushioning properties, and is excellent in workability for application without causing wrinkles. For this reason, a material made of closed-cell foamed polyethylene is preferably used. The thickness of the sheet body 1 is preferably about 1 to 5 mm. In other words, if it is less than 1 mm, it lacks the ability to absorb steps at the connection points between formworks and irregularities on the formwork surface, which not only deteriorates the finished surface condition of the concrete surface, but also makes it impossible to obtain the required strength. It is not suitable for practical use because it is likely to tear during the adhesion work, and the sheet body 1 itself is likely to wrinkle due to the heat generation of the concrete during adhesion and during the curing period after concrete placement. On the other hand, if the thickness exceeds 5 mm, the bulk will increase, which is disadvantageous in terms of transportation, storage, and even adhesion work.Not only will the material cost be high, but the joint portion 7 during use as shown in FIG. This results in disadvantages such as the height difference becoming larger. In the case of foamed polyethylene, it is more desirable to use one with a thickness of approximately 2 to 3 mm. Further, if the foaming ratio of the sheet body 1 is less than 20 times, the sheet body 1 lacks cushioning properties and is inferior in workability. On the other hand, if it is 60 times or more, the cushioning properties will be too high and the finished dimensional accuracy of the concrete will deteriorate. Therefore, the foaming ratio is 20~
It is desirable that it be about 60 times. In the case of foamed polyethylene, one having an expansion ratio of approximately 20 to 40 times is preferably used.

On one side of the sheet body 1, a high-pressure polyethylene film 2, which has been provided with fine irregularities 2a by embossing, is laminated and heated under pressure. In this invention, it is necessary to use a high-pressure polyethylene film 2. This film 2 by itself has extremely good releasability against concrete C, is inexpensive, lightweight, and can be easily cut, and when it is laminated and integrated with the sheet body 1, it has an appropriate tensile strength as a whole. is obtained, and there is no inconvenience such as wrinkles or damage when peeled off from the formwork or sheathing plate 4. Furthermore, it is water resistant, has good thermal stability, and has little thermal expansion and contraction, so it is easy to stick and pull. It has good peeling workability and can provide an extremely good concrete surface finish. this film 2
If the thickness is less than 15 μm, appropriate tensile strength cannot be obtained, and if it is more than 50 μm, the material will not only lack flexibility and have poor workability, but also increase material costs. Therefore, it is preferable to use a material having a thickness of about 15 to 50 μm. More preferably 20~
A material with a diameter of about 40 μm is used. Furthermore, the film 2 has fine irregularities 2 formed by embossing.
It is necessary that a is given. The irregularities 2a may take any form, such as a striped pattern, a so-called silk grain pattern, or a tortoiseshell pattern. The reason why the unevenness 2a is formed in this way is to form unevenness corresponding to the unevenness 2a on the concrete surface to obtain a good finished state, and also to form this concrete peeling sheet A as shown in FIG. This is to prevent the adhesive layer 3, which will be described later, from firmly adhering to the surface even when rolled up, thereby eliminating the need for release paper as in conventional products.

On the other hand, a pressure-sensitive adhesive layer 3 is previously provided on the other surface of the sheet main body 1 in order to perform the adhesion work reliably and easily. This adhesive layer 3 has a sufficient adhesion effect to the formwork to the extent that the sheet A can be peeled off from the concrete together with the formwork after the concrete has hardened, and can also be easily peeled off and removed from the formwork. In addition, it is desirable that the performance is less likely to deteriorate regardless of differences in temperature and humidity due to differences in region or season of use. For this reason, acrylic pressure-sensitive adhesives are preferably used.

Next, a specific usage example of the above-mentioned concrete peeling sheet A will be shown.

columns of reinforced or steel-framed concrete buildings;
When constructing beams, walls, floors, stairs, etc., or the foundations, waist walls, underground beams, etc. of steel frame or unreinforced concrete buildings, formwork must be assembled at the construction site in advance as shown in Figure 3. After that, the concrete peeling sheet A is completely laid along the inner surface of the weir plate 4 of the formwork through the adhesive layer 3 on the back side of the sheet A to complete the formwork apparatus. Above sheet A
Concrete C is poured into a weir 4 surrounded by concrete, and after it solidifies, the formwork and the weir 4 are removed.

In addition, holes for anchor bolts are provided in the foundations of concrete buildings, foundations for equipment installation, etc., or holes for forming openings such as through holes in ceilings, walls, floors, beams, etc. When forming openings such as holes in concrete structures such as formwork, synthetic resin pipes such as vinyl chloride, paper tubes, metal pipes such as stainless steel, aluminum, and iron, natural materials such as wood, bamboo, etc. , the concrete peeling sheet A is applied to the surface of the part of the embedding formwork 5 for embedding a block molded product such as cement, bricks, etc., glass pipes, etc. to be embedded in the cement C, via the adhesive layer 3 on the back side thereof. After pasting and directly positioning and inserting and fixing this into a formwork for forming a concrete foundation, etc., concrete for the foundation is placed, and after solidification, it is pulled out using a hanging fitting 6 or the like.

Effects of the invention As described above, in this invention, a high-pressure polyethylene film 2 is laminated and integrated on one side of a flexible foamed synthetic resin sheet body 1, and a pressure-sensitive adhesive layer is formed on the other side of the sheet body 1. Since the film 3 is formed by coating, the adhesive layer 3 makes it extremely easy to attach the film to the formwork, and the removability of the film 2 to concrete makes it extremely easy to remove the formwork. It can be done neatly, has good workability, and can significantly shorten the construction period. Further, since the sheet body 1 and the film 2 are laminated and integrated, sufficient tensile strength can be obtained even when peeling from the mold, and there is no problem of tearing. , and the film 2
Since it is water resistant, so-called jitters and the like will not occur due to loss of the cement paste due to penetration into the formwork, and as a result, the desired design strength and accuracy can be ensured through proper concrete mixing. can be maintained. In addition, the film 2
Since fine irregularities 2a are formed by embossing, irregularities corresponding to the irregularities 2a are formed on the concrete surface, and not only can the surface finish be made beautiful, but also the concrete peeling sheet Even if A is rolled up as shown in FIG. 1, the contact area with the adhesive layer 3 is small and the adhesive force is weak, so it can be easily peeled off. There is no inconvenience such as a part of the material remaining attached. Therefore, as mentioned above, the concrete release sheet A can be provided in the form of a roll, which is convenient for transportation and storage.Moreover, release paper can be eliminated, reducing material costs, and it can be provided in the form of a roll. There is no need to peel off the release paper and stick it on.
This operation can be performed extremely easily, and the trouble of disposing of release paper that is no longer needed can be eliminated.

Furthermore, the sheet main body 1 has a thickness of 1 to 5
Since it is made of flexible foamed synthetic resin with a diameter of 1.5 mm, unevenness on the surface of the formwork and slight differences in the shedding plates can be corrected to almost flatness, making it possible to finish the concrete surface flat, and especially when forming openings in concrete. By adhering it to the surface of the embedded formwork, the flexibility of the sheet body 1 and the easy peelability of the film 2 from the concrete prevents any damage to the area around the opening. It is convenient because the frame can be easily pulled out.

As described above, this invention has excellent practical effects that can solve all the problems that have conventionally been encountered when constructing concrete buildings and forming openings.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention; Fig. 1 is a perspective view showing a wrapped concrete peeling sheet according to this invention, Fig. 2 is an enlarged cross-sectional view of the sheet, and Fig. 3 is an illustration of the sheet wrapped in concrete. FIG. 4 is a cross-sectional view showing a state in which the sheet is adapted to form an opening and an opening. 1... Foamed synthetic resin sheet body, 2... High-pressure polyethylene film, 2a... Irregularities, 3... Pressure-sensitive adhesive layer. A...Concrete peeling sheet, C...Concrete.

Claims (1)

[Claims for Utility Model Registration] (1) A high-pressure polyethylene film 2 with fine irregularities 2a formed by embossing is laminated and integrated on one side of a flexible foamed synthetic resin sheet body 1 with a thickness of 1 to 5 mm. A concrete peeling sheet characterized in that a pressure-sensitive adhesive layer 3 is applied and formed on the other surface of the sheet main body 1. (2) The concrete peeling sheet according to claim 1, wherein the foamed synthetic resin sheet body 1 is made of closed-cell foamed polyethylene. (3) The concrete peeling sheet according to claim 1 or 2, wherein the foamed synthetic resin sheet body 1 is foamed 20 to 60 times. (4) The concrete peeling sheet according to any one of claims 1 to 3, wherein the high-pressure polyethylene film 2 has a thickness within the range of 15 to 50 μm.