JPH0380953B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a concrete formwork and a method for manufacturing the same, and aims to obtain a concrete formwork that has good peelability from concrete and can be reused many times. It is.

[Conventional technology]

Conventionally, this type of concrete formwork has been provided by forming a thick layer of acrylic resin, urethane resin, etc. on the surface of plywood (generally called painted formwork).

[Problem that the invention seeks to solve]

These concrete formworks have smooth surfaces, and the adhesion force due to the anchoring effect of concrete is reduced, so the mold release effect is improved. In addition, since the durability of the plywood itself has been improved by improving its waterproof properties through the coating, the number of times it has been reused as formwork has increased compared to plywood formwork that has not been subjected to any surface treatment. Ta.
That is, plywood formwork for 1 to 3 turns, painted formwork for 5 to 3 turns.
7 rotations is a common number of diversions.

However, since the surface of painted formwork is smooth, the concrete surface has a mirror finish, and when applying mortar to the concrete surface, the adhesion between the mortar and the anchor effect decreases, causing peeling. There remains the problem that it becomes easier to do.

Furthermore, the coating surface is weak and easily damaged by impact and abrasion during concrete pouring, which causes problems such as a decrease in the mold release effect and sun cracking on the coating surface after long-term use. have

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a substrate 1
An unsaturated polyester resin prepared by adding and mixing zinc or a zinc compound is coated on top of the resin, and while the unsaturated polyester resin is in an uncured state, a paper 3 is placed on top of the resin to form an uncured resin paper laminate. A plurality of sheets of this resin-uncured paper laminate plate A are stacked with the unsaturated polyester resin in an uncured state, and during the stacking period, the layer on the resin side of the paper 3 is impregnated with the unsaturated polyester resin. Let it polymerize and harden.
Furthermore, the desired concrete formwork is obtained by coating and impregnating the surface of the resulting cured resin plate-like body B with an aqueous solution or dispersion of zinc or a zinc compound.

[Effect]

Since the concrete formwork of the present invention is constructed as described above, it has the following effects.

(a) Since the concrete formwork of the present invention is impregnated with unsaturated polyester resin at the interface between the paper 3 and the unsaturated polyester resin layer 2, the flexibility of the resin-impregnated fibers of the paper 3 makes the resin layer No coating film cracks occur.

(b) Since the surface of paper 3 is impregnated with zinc or a zinc compound, when concrete formwork is poured into concrete, the interface area of the poured concrete (range 0.2 to 0.3 m/m of the concrete surface)
Zinc or zinc in zinc compounds is eluted into cement paste with alkaline water.

Cement paste is hardened by a hydration reaction, but since zinc is eluted into the cement paste, the hydration reaction that occurs at that time causes calcium silicate (C-S-H) and calcium hydroxide (Ca(OH) ₂ ) and the calcium salt of zincate (Ca[Zn(OH) ₃ ·H ₂ O] ₂ ) are produced.

This product, calcium salt of zincic acid (Ca[Zn(OH) ₃ . H ₂ O] ₂ ), has a flaky or plate-like crystal structure, so entanglement between crystals is weak and delamination between crystals occurs. At the same time, the anchoring effect on the substrate surface decreases.

In addition, due to the generation of hydrogen due to the reaction between alkali and zinc, a porous structure is created, which weakens the structural strength at the interface between the formwork and concrete, that is, in the range of 0.2 to 0.3 m/m of the concrete surface.

Furthermore, zinc ions have the effect of suppressing (delaying) the hydration reaction of cement paste.

Therefore, the adhesion of the cement paste in the interface area between the concrete formwork and the poured concrete is reduced, and the mold release effect is improved.

(c) Even if the surface of the concrete form is damaged due to impact or abrasion during concrete pouring, the paper layer on the surface of the concrete form is impregnated with zinc or a zinc compound, and the surface paper layer of the concrete form is impregnated with zinc or a zinc compound. Since the resin-impregnated paper layer and resin layer are formed, the mold release effect at the damaged area does not deteriorate.

(d) Furthermore, as mentioned above, the concrete surface is formed into a rough surface due to the presence of the zinc-impregnated layer 3b on the surface of the paper 3, and when the concrete formwork is peeled off, a part of the paper 3 is peeled off and left behind. Therefore, when the decorative mortar is overcoated, the anchoring effect of the decorative mortar does not deteriorate.

Furthermore, the concrete formwork can be mass-produced by depositing the uncured resin paper laminate plate A as described above.

[Explanation of configuration]

As shown in Figure 1, an unsaturated polyester resin mixed with a curing agent, an accelerator, and zinc or a zinc compound is coated on the surface of the substrate 1 using a coating device such as a roll coater, flow coater, or spray. A cured unsaturated polyester resin layer 2' is formed.

Plywood, fiberboard, wood chip board, etc. are used as the substrate 1, and as the unsaturated polyester resin, wax-added unsaturated polyester resin or non-wax type unsaturated polyester resin is used.

Curing agents include organic peroxide curing agents such as benzoyl peroxide, methyl ethyl ketone, peroxide, acetyl peroxide, ketone peroxide, and acyl peroxide; accelerators include cobalt accelerators, vanadium accelerators,
Manganese-based accelerators, tertiary amine-based accelerators, etc. are used.

The zinc or zinc compound may be any zinc compound including granular or powdered zinc and zinc acetate, zinc carbonate, zinc chloride, zinc nitrate, zinc oxide, zinc hydroxide, zinc sulfate, zinc sulfide, zinc sulfite, and the like.

For example, using a roll coater, 40 to 80 g of unsaturated polyester resin to which 50 to 60% of methyl ethyl ketone peroxide as a hardening agent and 0.1 to 1% of additives and 5% of zinc sulfate powder as a zinc compound were added. Apply ² /m2.

Immediately coat the top surface with cobalt naphthenate cobalt 3-10, which is a cobalt-based accelerator, using a flow coater.
% additives are added from 0.1 to 1%. Furthermore, an uncured unsaturated polyester resin layer 2' is formed by applying 40 to 80 g/m ² of an unsaturated polyester resin to which 5% of zinc sulfate powder is added as a zinc compound.

Next, while the resin is in an uncured state, that is, on the uncured unsaturated polyester resin layer 2', paper 3 is pasted using a laminator device.

The unsaturated polyester resin used is one dissolved in monomers (mostly styrene).

As the paper 3, any material such as textured or ungrained thin paper, cardboard, nonwoven fabric, synthetic paper, etc. may be used.

In this way, the uncured unsaturated polyester resin layer 2' is deposited on the surface of the substrate 1, and the resin uncured paper laminate plate A with the paper 3 laminated thereon is deposited, and during the deposition period, the unsaturated polyester resin layer is deposited. Polymerizes and hardens.

When the uncured resin paper laminate plate A is deposited in this way for a long time, the resin is impregnated into the paper 3 by deposition at the interface between the uncured layer 2' of unsaturated polyester resin and the paper 3. This impregnated layer is also called a resin impregnated layer 3a.

The unsaturated polyester resin is in a form dissolved in monomers (mostly styrene), and since the paper 3 is formed on the surface of the uncured layer 2' of the resin, the styrene monomer evaporates and the styrene monomer evaporates. The styrene monomer is filled between the fibers of the paper 3 which is not impregnated with unsaturated polyester resin. For this purpose, the uncured layer 2' of unsaturated polyester resin is cut off from contact with air (oxygen in the air), and the curing agent,
Polymerization and curing is accomplished by the action of an accelerator. In this way, a resin-impregnated cured layer 3a is formed in the paper 3 on the unsaturated polyester resin layer 2 side.

In this way, the unsaturated polyester resin layers 2 and 3 are pasted on the surface of the substrate 1, and the paper 3 is pasted on the resin layer, and at least the unsaturated polyester resin is impregnated at the interface of the paper layer 3 and polymerized and hardened. A resin-impregnated layer 3a is obtained.

Furthermore, a roll coater is applied to the surface of the obtained plate-shaped body.
A synthetic resin mixed with zinc or a zinc compound is applied using a coating device such as a flow coater or a sprayer. In this way, the zinc impregnated layer 3
b is formed.

Zinc or zinc compounds include zinc and zinc acetate, zinc carbonate, zinc chloride, zinc nitrate, zinc oxide,
Any zinc compound including zinc hydroxide, zinc sulfate, zinc sulfide, zinc sulfite, etc. may be used, and an aqueous solution or dispersion thereof may be used.

A penetrant (surfactant) may be added to the aqueous solution or dispersion to promote its penetration into the paper layer.

A concrete formwork is obtained by coating and impregnating an aqueous solution or dispersion of zinc or a zinc compound and then drying it using a drying device.

〔Effect of the invention〕

(a) On the surface of the substrate 1, a resin layer 2, a resin-impregnated paper layer 2a,
Since the paper 3 was formed and the unsaturated polyester resin was used for the resin layer 2, the mold release from the concrete was good and the releasability was improved.

(b) The waterproof property of the resin layer formed on the surface protects the substrate 1 from corrosion caused by alkaline water in concrete, and the unsaturated polyester resin improves abrasion resistance, impact resistance, and chemical resistance.

(c) Furthermore, due to the flexibility of the fibers of the resin-impregnated paper 3, the resin layer did not develop coating cracks, and the number of times it could be used as concrete formwork was significantly increased.

(d) Furthermore, since the paper 3 is laminated on the surface of the concrete formwork, the concrete surface after concrete pouring and hardening exhibits a moderately rough surface, making it possible to smoothly apply decorative mortar to the concrete surface.

(e) The resin layer 2 mixed with zinc or a zinc compound on the surface of the substrate and the surface paper 3 impregnated with zinc or a zinc compound. It reduces the adhesion and improves the releasability.

(f) Zinc is leached each time it is used as a formwork, and even if the surface is damaged by concrete pouring, the mold release effect will not deteriorate because the impregnated zinc will be leached out.

[Brief explanation of drawings]

FIG. 1: An explanatory diagram of the first step of the manufacturing method of the present invention,
FIG. 2: An explanatory diagram of the second process, FIG. 3: An explanatory diagram of the third process, and FIG. 4: A side view of the concrete formwork of the present invention. 1...Substrate, 2...Unsaturated polyester resin layer,
2'... uncured unsaturated polyester resin layer, 3... paper,
3a...Resin-impregnated layer, 3b...Zinc-impregnated layer, A...Resin uncured paper laminate plate, B...Resin cured plate.

Claims (1)

[Claims] 1. An unsaturated polyester resin layer 2 mixed with zinc or a zinc compound on the surface of a substrate 1, a paper 3 layered on the resin layer 2, and a layer of paper 3 on the resin layer 2 side of the paper 3. A resin-impregnated layer 3a is formed in which at least unsaturated polyester resin is impregnated and polymerized and cured, and a zinc-impregnated layer 3b is formed in the layer on the surface side of the paper 3, in which zinc or a zinc compound is impregnated. Concrete formwork characterized by: 2. An unsaturated polyester resin mixed with zinc or a zinc compound is applied to the surface of the substrate 1, and while the unsaturated polyester resin is in an uncured state, paper is overlaid on the surface to form a resin-uncured paper laminate plate A. After forming, a plurality of sheets of the paper laminate plate A are stacked with the unsaturated polyester resin in an uncured state, and during this stacking period, the layer on the resin side of the paper is impregnated with the unsaturated polyester resin. At the same time, a cured resin plate B is formed by polymerizing and curing this unsaturated polyester resin, and the surface of the obtained cured resin plate B is coated and impregnated with an aqueous solution or dispersion of zinc or a zinc compound, and then dried. A method for manufacturing concrete formwork, characterized by: obtaining a desired concrete formwork.