JPS59102053A - Concrete mold frame and production thereof - 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] The present invention relates to a concrete formwork and a method for manufacturing the same = 1
- related.

Conventionally, concrete formwork has been used in which impregnated paper impregnated with synthetic resin such as phenol resin or melamine resin is adhered to the surface of plywood.

By pasting impregnated paper on the surface of plywood in this way, the surface strength can be improved, the plywood can be prevented from deteriorating due to the absorption of alkaline water in cement, and the concrete surface can be hardened by extracting soluble components from the plywood with alkaline water. Prevention of inhibition is achieved.

In addition, the surface of this impregnated paper is made of plastic, which prevents scratches on the surface and prevents cement from adhering to the surface.In other words, it has good removability, can be used more often as a formwork, and has a smooth surface that allows it to be used as a mold. In construction, it has the effect of creating a beautiful finish on concrete surfaces.

In this case, the impregnated paper used is impregnated paper in which the impregnated synthetic resin is completely cured, semi-cured impregnated paper, or uncured impregnated paper.

Although considerable advantages can be obtained by pasting impregnated paper as described above, the following problems remain in the conventional method.

(2) When adhering impregnated paper with completely cured synthetic resin, an optional adhesive is applied to the surface of the plywood or the back of the impregnated paper, and the sheets are laminated via the adhesive and bonded under heat and pressure. However, at this time, the impregnated paper 1 becomes plastic due to complete hardening of the synthetic resin, so the activity of the impregnated resin is lost and its adhesive strength is reduced.

■ When adhering impregnated paper with semi-cured or uncured synthetic resin, the impregnated paper is laminated on the surface of the plywood and bonded using the self-adhesive force of the impregnated resin by hot pressing. In this case, the synthetic resin must be completely cured by heat and pressure, which requires a long heat and pressure time, and high heat and pressure temperatures are required for phenol resins, melamine resins, and the like.

■ In the case of high-pressure impregnation, the resin flows due to the pressure and temperature during hot pressure, and the synthetic resin tends to adhere to the hot plate and mirror plate, leading to a decrease in quality. Therefore, it is necessary to use methods such as inserting release paper between impregnated paper and a hot plate and applying heat pressure, or applying heat pressure at low temperature and pressure to reduce the flow of the resin, which reduces productivity and increases cost. It was the cause.

■ When phenolic resin-impregnated paper is laminated and bonded under heat and pressure, a phenolic resin adhesive is used as the adhesive for the plywood, but in this case, the price of phenolic resin adhesive is 2 times lower than that of Uniar resin, for example. This will double, leading to a rise in costs.

■ When using a plywood adhesive other than phenolic resin, the temperature during hot pressing must be raised to a temperature that sufficiently hardens the impregnated synthetic resin, and the high heat causes the adhesive layer to form a bond. The adhesive deteriorates and the adhesive strength of the plywood itself decreases.

■ Because it is a high-temperature adhesive, if the moisture content of the plywood itself is high, punctures are likely to occur due to the evaporation of that moisture, so unless you adjust the moisture content of the plywood or press it at a low temperature for a long time, C will not be achieved. This also applies when a synthetic resin adhesive having a high curing temperature is used.

■ If the resin in the impregnated paper is left in an uncured state, when used as a formwork, the uncured resin may contaminate the concrete surface, cause curing failure, or reduce the hardness of the impregnated paper itself. Concrete is weak and easily scratches on the surface, so use concrete for those scratches!・Due to the anchoring effect, peeling from concrete does not occur smoothly, reducing the number of times it can be used as formwork.

The object of the present invention is to solve the above-mentioned problems of conventional concrete forms to which synthetic resin-impregnated paper is attached. That is, in the present invention, as described below, paper is pasted during hot pressing, and a release layer is formed by penetrating and impregnating the paper with a release agent or a synthetic resin. In this way, the present invention utilizes heat during hot pressing to bond paper and plywood, which eliminates waste in terms of process, provides sufficient adhesion, and allows easy release of concrete formwork, which is often reused. This is what we are trying to provide.

The specific configuration of the present invention will be explained below.

■ Apply adhesive to the surface of the veneer and layer thin paper on top of it to create a composite of the veneer and thin paper. The adhesive is a thermosetting adhesive such as urea resin, melamine resin, phenol resin, vinyl resin, and vinegar/vinyl resin, which is generally used in plywood production or paper pasting. 30~1s for thin paper
o g/m2 tissue paper, rayon paper, manila paper, synthetic paper, IQ-timento paper, kraft paper, non-woven fabric, etc. may be used.

■Next, multiple composites of veneer and thin paper are piled up, and the stack is cold-pressed to impregnate the adhesive into the veneer and thin paper and temporarily bonded, creating a temporarily bonded composite of veneer and thin paper. obtain. The amount of adhesive to be applied is appropriately determined depending on the type and viscosity of the adhesive, as well as the type and thickness of the thin paper. It is not preferable that the amount of adhesive applied is larger than necessary because the adhesive tends to seep through the thin paper and seep out onto the surface during cold pressing and later hot pressing.

For example, in the case of thin paper 1 of 30 to 150 g/m2, 5 to 1
A coating weight of 50 g/m2 is preferred.

■ Next, the obtained temporarily bonded composite is used as a front veneer, and the front veneer and multiple veneers are laminated with an adhesive so that the thin paper of the front veneer faces the top surface to form a laminate. .

The adhesives used here are those commonly used in plywood manufacturing, such as urea resin, melamine resin, and phenol 411/fat.

The front veneer and the veneer may be laminated in either an even number or an odd number, and the fiber directions of the veneers may be parallel or orthogonal.

(2) Next, after stacking a plurality of the laminates, the stacks are cold-pressed and temporarily bonded.

■ Next, the temporarily bonded laminate is simultaneously hot-press molded according to the plywood manufacturing conditions. In this way, plywood with tissue paper pasted on its surface is obtained.

In the obtained plywood, the adhesive sufficiently penetrates and impregnates the veneer or thin paper, and is cured, so that the veneer and the thin paper are firmly bonded.

Next, the surface of the plywood is ground as necessary to remove surface paper that is not impregnated with adhesive. After temporary adhesion by cold pressing in this way,
Thin paper is pasted by hot-press molding, and the adhesive sufficiently penetrates into the veneer or thin paper, and the adhesive is cured to improve adhesive strength.

Further, if necessary, by polishing and removing the surface paper that is not impregnated with the adhesive of the thin paper, the surface is smoothed and a reinforced part impregnated with the adhesive and hardened is revealed on the surface, improving the surface strength.

■Next, a release agent is applied to the thin paper layer on the surface of the plywood, and a release tank is formed by penetrating and impregnating the thin paper.

Instead of a mold release agent, a synthetic resin may be applied to form a release layer. As the mold release agent, emulsion resin type, phenol resin type, epoxy resin type, urethane resin type, etc. are used.

When a mold release agent is applied, the mold release agent itself does not become strong when it dries, and as a result, paper-to-paper peeling tends to occur in areas of the surface paper that are not impregnated with the adhesive. Therefore, it is preferable to apply the adhesive after polishing off the portion that is not impregnated with the adhesive to make the surface layer a reinforced portion.

When a synthetic resin is applied, the resin permeates and impregnates paper parts that are not impregnated with the adhesive and becomes a reinforced part, so there is no need to grind the surface. (Although there is no problem with grinding.) In this way, a concrete formwork with a mold release agent layer or a synthetic resin layer formed on the surface of the thin paper is obtained.

In addition, in the process of ■~■ above, thin paper and multiple veneers are laminated with adhesive so that the thin paper is on the top surface, and then cold press temporarily bonded, and then hot pressure molded to form plywood. good.

(Actions and effects of the present invention) The effects of the present invention are summarized as follows.

(2) Since paper is applied to the surface of the plywood at the same time as the plywood is manufactured, the paper is easily applied and the adhesive strength is improved, which improves productivity.

(2) The back side of the paper layer is impregnated with an adhesive, and the front side is coated with a rounding agent or synthetic resin to improve mold releasability.

■ When applying a mold release agent, remove by polishing the portion of the paper surface that is not impregnated with adhesive.-9-tsts.

Therefore, the thin paper is strengthened, and when applying synthetic resin, the synthetic resin is applied and impregnated to form a reinforced portion without grinding the surface portion of the paper that is not impregnated with adhesive.

In this way, the surface of the mold is less likely to be scratched, and together with the mold releasability, the number of times the mold can be used can be greatly increased.

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Claims (1)

[Claims] (11) A paper layer ♂ whose surface is impregnated with an adhesive during plywood production and adhered through the adhesive; peeled off with a release agent or synthetic resin that is impregnated into the surface of the paper layer. Concrete formwork characterized by forming layers. (2) Thin paper is laminated on the surface of the veneer via adhesive, the front veneer is cut, and the front veneer and a plurality of veneers are attached to the front veneer. The thin paper of the veneer is laminated via an adhesive so that the top surface is the top surface, and this laminate is simultaneously hot-press molded according to the plywood manufacturing conditions.Then, the surface of the obtained plywood and the thin paper surface are molded as necessary. 1. A method for manufacturing concrete formwork, characterized in that after grinding, a release agent or synthetic resin is applied to the entire surface and penetrated and impregnated into the thin paper layer on the second side to form a release layer.