JP2003221928A - Covering seat for form surface for placing concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of securely preventing concrete from sticking to a form body for placing concrete and smooth repetitive use of a concrete placing form. <P>SOLUTION: The covering sheet has a synthetic resin sheet and a surface layer made of a cohesive formed on the one side face. The exposed face of the resin sheet has a concrete peelability, and the surface layer is detachably stuck to the form surface for placing concrete. The sheet has an adhesion preventive function between the form and concrete on placing concrete. By covering the surface of a form for placing concrete, adhesion of concrete onto the form body is effectively prevented and repeated use of the form can be smoothly realized. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover sheet for the surface of a concrete pouring formwork which is detachably attached to a concrete pouring surface of a concrete pouring formwork.

[0002]

2. Description of the Related Art Concrete pouring formwork is used for concrete pouring at civil engineering construction sites, and wood, metal, resin, etc. are used as the material of such concrete formwork. Each time a wooden formwork is used, the condition of the surface in contact with the concrete deteriorates and the concrete gradually becomes less likely to peel off, so it can only be used repeatedly several times. On the other hand, the metal formwork also has a problem of concrete adhesion. Therefore, the metal mold is usually used by applying an oil-based release agent on the surface thereof, but it takes time and effort to apply the release agent and also has an adverse effect on the environment. In addition, resin molds that have become widespread in recent years generally have excellent concrete releasability, but during repeated use, concrete easily becomes more likely to adhere to the surface, and after several times of repeated use, it adheres to the surface. It is necessary to remove the existing concrete by shaving work and apply a release agent.

[0003]

Under such circumstances, the present invention can reliably prevent concrete from adhering to the concrete pouring formwork main body and facilitate the repeated use of the concrete pouring formwork. It aims to provide the technology to achieve.

[0004]

The present invention comprises a resin sheet and a surface layer formed on one surface of the resin sheet, the exposed surface of the resin sheet having concrete releasability, A covering sheet for a concrete pouring formwork surface, wherein the surface layer has a function of being adhered to the surface of a concrete pouring formwork to prevent adhesion between concrete and the formwork during concrete pouring. provide. Since the covering sheet has concrete releasability on the exposed surface of the resin sheet, it is possible to easily remove the formwork from the concrete after placing the concrete using the formwork to which the covering sheet is stuck. it can. Furthermore, when concrete adheres to the surface of the covering sheet and cannot be easily removed, the used concrete covering sheet is peeled off from the mold to easily remove the adhered concrete from the mold. be able to. By peeling the used covering sheet and then attaching a new covering sheet to the surface of the mold, the mold can be reused in a good condition. In the covering sheet of the present invention, the resin sheet may be a single-layer resin sheet, or may be a multi-layer sheet in which a plurality of unit resin sheets are laminated via a layer made of an adhesive. In the latter case, when concrete adheres to the exposed surface of the resin sheet, only the unit resin sheet on the outermost side where the concrete adheres is peeled off together with the adjacent adhesive layer to remove the peeling. The unit resin sheet immediately below the prepared pressure-sensitive adhesive layer is newly exposed, and a good surface state equivalent to the state before use is restored.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the coating sheet of the present invention,
As the resin sheet, sheets made of various thermoplastic resins can be applied. As the thermoplastic resin, polyester resin, polyalkyl (meth) acrylate,
Polyolefin resins (for example, ethylene polymers, ethylene copolymers, propylene polymers, propylene copolymers, etc.) and the like can be mentioned. Above all, they have excellent releasability from concrete and are relatively easy to recycle. A polyolefin resin is preferable because it produces less toxic gas during combustion. Among the polyolefin resins, polypropylene resins, that is, propylene polymers and propylene copolymers are preferable from the viewpoint of mechanical strength, hardness, heat resistance and the like.

In the covering sheet of the present invention, the pressure-sensitive adhesive constituting the surface layer includes not only those generally used as pressure-sensitive adhesives but also those usually used as adhesives. The pressure-sensitive adhesive applied to the present invention can be appropriately selected from various pressure-sensitive adhesives and adhesives in consideration of the material of the formwork to which the coating sheet of the present invention is attached, for example,
Acrylic, vinyl ether, silicone, rubber,
Examples thereof include urethane-based and epoxy-based pressure-sensitive adhesives or adhesives. The pressure-sensitive adhesive is the adhesive strength (when peeled at 90 degrees) Cs between the surface layer made of the pressure-sensitive adhesive and the frame to which the covering sheet is attached.
Is preferably 300 gf / 25 mm or more and 1500 gf / 25 mm or less. When the adhesive force Cs between the surface layer and the surface of the mold is 300 gf / 25 mm or more and 1500 gf / 25 mm or less, the mold is removed from the concrete after placing the concrete using the mold to which the covering sheet is attached. At this time, the covering sheet is not peeled off from the surface of the mold, and can be easily peeled off when peeling the used covering sheet from the mold. The type of the pressure-sensitive adhesive is not particularly limited, and for example, a solution-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot melt-type pressure-sensitive adhesive and the like can be applied.
The thickness of the surface layer made of an adhesive is not particularly limited, but generally about 10 to 50 μm is suitable.

The thickness of the coating sheet of the present invention is not critically limited and may be appropriately determined according to the kind of resin constituting the resin sheet, but generally 50 μm or more and 1 mm.
The following degree is preferable, and about 50 μm or more and 500 μm or less is more preferable. When the thickness of the covering sheet is within such a range, the covering sheet can be easily attached to the mold without forming wrinkles, and can be smoothly peeled off. When the thickness of the covering sheet is 50 μm or more, it is possible to effectively prevent the generation of wrinkles at the time of sticking and the breakage at the time of placing concrete. From the viewpoint of the state of the concrete surface that is formed when concrete is placed using two or more connected formwork to form a wall surface,
The thickness of the covering sheet is preferably about 1 mm or less.

[0008] The adhesive force Cc between the exposed surface of the resin sheet and the concrete (at the time of 90 degree peeling) may be smaller than the adhesive force Cs between the surface layer made of the adhesive and the surface of the mold to which the covering sheet is attached. preferable. When Cc is larger than Cs, the covering sheet is peeled off from the surface of the mold when the mold is removed from the cast concrete. In order to reduce the adhesive force between the exposed surface of the resin sheet and concrete, the exposed surface of the resin sheet is preferably treated with a silicone-based or fluorine-based release agent. The treatment of the resin sheet surface with the release agent can be performed, for example, by applying the release agent or a solution or dispersion containing the release agent to the surface of the resin sheet.

In addition, the resin sheet contains 0.1% by weight or more and 30% by weight or less of a modified resin selected from a fluorine-modified resin and a silicon-modified resin so that good concrete releasability can be maintained for a long time. Is preferred. When such a modified resin is added to improve concrete peelability, if the amount of the modified resin is less than 0.1% by weight, the concrete peelability is not sufficiently improved, and
If it is more than 30% by weight, the concrete peeling property will not be improved any more, and the strength of the resin sheet will be lowered, and the cost will be disadvantageous.

In the present invention, the resin sheet may be a single-layer resin sheet, or may be a multi-layer resin sheet in which a plurality of unit resin sheets are laminated with a layer made of a pressure-sensitive adhesive interposed therebetween. Here, the unit resin sheet means a thin single-layer resin sheet or a thin multi-layer sheet composed of a plurality of layers that are firmly bonded and integrated so as not to separate between layers. When a concrete sheet adheres to the exposed surface of the resin sheet in a covering sheet made of a multi-layer resin sheet, only the unit resin sheet on the outermost side where the concrete is attached remains with the adjacent adhesive layer. By peeling and removing from the portion, the unit resin sheet immediately below the peeled and removed pressure-sensitive adhesive layer is newly exposed, and a good surface state equivalent to the state before use is restored.

The thickness of the unit resin sheet in the multilayer resin sheet is not particularly limited as long as the unit resin sheet has a peelable strength, and the total thickness of the covering sheet is usually about 1 mm or less. In addition, although it may be appropriately determined according to the number of unit resin sheets to be laminated, the lower limit of the thickness of the unit resin sheet is about 10 μm, which is 10 μm.
This is because if it is thinner than that, it is easy to tear at the time of peeling. The type of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer provided between the unit resin sheets is not particularly limited, and, for example, a solution-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot melt-type pressure-sensitive adhesive or the like can be applied. The thickness of the pressure-sensitive adhesive layer made of a pressure-sensitive adhesive is not particularly limited, but generally about 5 to 10 μm is suitable.

When the resin sheet is a multi-layer resin sheet, for each unit resin sheet constituting the multi-layer resin sheet, one unit resin sheet and a unit resin sheet adjacent to the unit resin sheet are Adhesive force Cn with the layer of the pressure-sensitive adhesive on the side far from the surface layer, and the unit resin sheet and the pressure-sensitive adhesive on the side farther from the surface layer than the layer of the pressure-sensitive adhesive adjacent to the layer of the pressure-sensitive adhesive. The adhesive force Cf with the layer of the formula is:
It is preferable to satisfy Cf> Cn.

Further, the adhesive force C _u between the surface of one unit resin sheet far from the surface layer and the concrete is the unit resin sheet and each unit resin sheet not farther from the surface layer than the unit resin sheet and those unit resin sheets. It is preferable that it is smaller than the adhesive force between each pressure-sensitive adhesive layer adjacent to and the adhesive force Cs between the surface layer and the mold surface.

In order to properly control the adhesive force between each unit resin sheet and concrete, the surface of each unit resin sheet far from the surface layer is preferably treated with a silicone-based or fluorine-based release agent. Further, each unit resin sheet may contain a modified resin selected from a fluorine-modified resin and a silicon-modified resin in an amount of 0.1% by weight or more and 30% by weight or less so that good concrete releasability can be maintained for a long time. preferable. When such a modified resin is added to improve concrete peelability, when the amount of the modified resin is less than 0.1% by weight, the concrete peelability is not sufficiently improved, and more than 30% by weight. If it is too much, the concrete peeling property will not be improved anymore, and the strength of the resin sheet will be deteriorated, which is also disadvantageous in terms of cost.

[0015]

EFFECTS OF THE INVENTION When concrete is cast using a plywood, metal or resin mold, if the covering sheet of the present invention is adhered to the surface of the mold, the concrete mold surface It can be effectively prevented from adhering to the mold, and the life of the mold can be remarkably extended. Further, by peeling off the covering sheet after use, if necessary, and replacing it with a new sheet, it is possible to always maintain a good surface condition when using the mold. Further, in the case of a covering sheet having a plurality of unit resin sheets, the unit resin sheet is peeled off when the concrete adheres, so that a good surface condition can be always maintained when the mold is used.

[0016]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. Example 1 Polypropylene resin (MI (melt index): 2.0 g / 10 min homopolymer) was plasticized at a temperature of 220 ° C. by a kneading extruder, and then a molding die was used to obtain a film having a thickness of 200 μm. The sheet was processed. Corona treatment was applied to one surface of this sheet, and an acrylic adhesive was applied to the treated surface to a thickness of 10 μm to obtain a coating sheet (thickness 210 μm; hereinafter referred to as sheet I). .

(Example 2) Polypropylene resin (MI
(Melt index: 2.0 g / 10 min homopolymer) was plasticized by a kneading extruder at a temperature of 220 ° C., and then a sheet having a thickness of 200 μm was processed using a shaping die. Corona treatment is applied to both sides of this sheet, one side is coated with an acrylic adhesive with a thickness of 10 μm, and the back side of this sheet is coated with a silicone release agent with a thickness of 3 μm for coating. A sheet (thickness 213 μm; hereinafter referred to as sheet II) was obtained.

(Example 3) Polypropylene resin (MI
(Melt index): 2.0 g / 10 min homopolymer) and fluororesin-modified polypropylene resin (BY27-
201; Toray Dow Corning Silicone) 5
After mixing by wt% and plasticizing at a temperature of 220 ° C. by a kneading extruder, a sheet having a thickness of 200 μm was processed using a shaping die. Corona treatment was applied to one side of this sheet, and an acrylic pressure-sensitive adhesive was applied to the treated side in a thickness of 10 μm to obtain a covering sheet (thickness 210 μm; hereinafter referred to as sheet III). .

(Example 4) Polypropylene resin (MI
(Melt index): 2.0 g / 10 min homopolymer) and fluororesin-modified polypropylene resin (BY27-
201; Toray Dow Corning Silicone) 5
After mixing by wt% and plasticizing with a kneading extruder at a temperature of 220 ° C., a film having a thickness of 30 μm was prepared using a shaping die. Corona treatment was applied to both sides of this film, a silicone-based release agent was applied to one side to a thickness of 3 μm, and an acrylic adhesive was applied to the back side of the film.
It was applied to a thickness of μm. A total of five films prepared in the same manner were laminated to obtain a coating sheet having a thickness of 215 μm (thickness 215 μ; hereinafter referred to as sheet IV).

[Evaluation] The coating sheets (sheets I to IV) produced in Examples 1 to 4 were attached to the concrete placing surface of the concrete placing form to produce a surface-coated form. The adhesive strength between the casting surface of the mold and the covering sheet is 90 °
It was measured by a peel test. Using this, concrete pouring and deframing were repeated, and the surface condition of the surface-coated mold was observed. As a control, concrete was repeatedly cast using a mold to which the covering sheet had not been adhered, and the condition of the mold surface was observed.

[0021]

[Table 1] * 1: The numbers in parentheses are the peel strength, and the other figures are 90 ° peel strength.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Tatsumi             2-27-1, Shinkawa, Chuo-ku, Tokyo             Within Lastec Co., Ltd. F term (reference) 4F100 AB02C AE20C AK01A AK17A                       AL06A AL08A AP02C BA02                       BA03 BA06 BA07 BA10A                       BA10C CB05B GB07 JL13B                       JL14 JL14A YY00A

Claims (11)

[Claims] 1. A resin sheet and a surface layer made of an adhesive formed on one surface thereof, the exposed surface of the resin sheet having concrete releasability, and the surface layer for concrete pouring. A sheet for covering the surface of a concrete pouring form, which is detachably attached to the surface of the form and has a function of preventing adhesion between concrete and the form during concrete pouring. 2. The adhesive strength Cs of the surface layer upon peeling at 90 degrees from plywood, steel plate or resin plate is 300 gf / 25 mm or more, 1
The covering sheet according to claim 1, wherein the covering sheet is 500 gf / 25 mm or less, and the Cs is larger than an adhesive force Cc between the exposed surface of the resin sheet and the concrete. 3. The covering sheet according to claim 1, wherein the resin sheet is a single-layer resin sheet. 4. The coating sheet according to claim 1, wherein the resin sheet is a multi-layer sheet in which a plurality of unit resin sheets are laminated with a layer made of a pressure-sensitive adhesive interposed therebetween. 5. An adhesive force Cn between one unit resin sheet and a pressure-sensitive adhesive layer adjacent to the unit resin sheet and farther from the surface layer than the unit resin sheet, and the pressure-sensitive adhesive of the pressure-sensitive adhesive. Adhesive force Cf between the adhesive layer and the unit resin sheet which is adjacent to the layer and is farther from the surface layer than the adhesive layer
Satisfies the formula: Cf> Cn, The covering sheet according to claim 4. 6. The covering sheet according to claim 4, wherein the surface of each unit resin sheet far from the surface layer has concrete releasability. 7. The covering sheet according to claim 4, wherein each unit resin sheet has a thickness of 10 μm or more. 8. The covering sheet according to claim 3, wherein the exposed surface of the resin sheet is treated with a silicone-based or fluorine-based release agent. 9. The covering sheet according to claim 4, wherein the surface of each unit resin sheet far from the surface layer is treated with a silicone-based or fluorine-based release agent. . 10. The resin sheet contains a modified resin selected from a fluorine-modified resin and a silicon-modified resin in an amount of 0.1% by weight or more and 30% by weight or less.
The coating sheet according to [4]. 11. At least one unit resin sheet contains a modified resin selected from a fluorine-modified resin and a silicon-modified resin in an amount of 0.1% by weight or more and 30% by weight or less. The covering sheet according to the above 1. The resin sheet is