JPH10138224A - Release sheet for concrete form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To upgrade releasability of concrete after curing by laminating a pressure sensitive adhesive layer on one surface of an olefin resin film containing specific amount of olefin resin and specific amount of concrete curing retarder. SOLUTION: An olefin resin film contains 100 pts.wt. of olefin resin and 0.01 to 8 pts.wt. of concrete curing retarder. Resin used for the film includes low-density, intermediate-density and high-density polyethylenes or polyethylenes, and ultraviolet absorbent, plasticizer and filler are added as needed. The retarder has a function of delaying curing reaction of concrete in case of curing curable concrete and composition, and includes gluconic acid, tartaric acid and citric acid. Adding amount of the retarder provides no effect of curing delay if it is less than 0.01 pts.wt., and lowers strength of the sheet if it exceeds 8 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a release sheet for a concrete formwork.

[0002]

2. Description of the Related Art Conventionally, concrete products or structures are made of a wooden form made of plywood or particle board, a metal form made of ordinary steel or galvanized steel, or a plastic molded form. Has been used. The above-mentioned wooden formwork takes advantage of inexpensiveness and the like, and is usually used by applying a release agent or a paint of a urethane type, an acrylic type, an epoxy type or the like to the surface, but the obtained concrete product or It has the disadvantage that the dimensional stability of the structure is poor and the durability is inferior to other forms.

[0003] On the other hand, metal molds are more expensive than wooden molds, but have the advantages of excellent dimensional stability, durability, and a remarkable increase in the number of reuses. However, metal molds, like wooden molds, have poor mold release properties with hardened concrete, and the surface finish of the resulting concrete product or structure is poor. It has the trouble of having to apply it. Also, the plastic molding form has an advantage that the releasability from concrete is good and the surface finish of the obtained concrete product or structure is beautiful, but it has a disadvantage that it is easily deformed and has poor durability. Have.

As an attempt to improve the releasability of the metal mold, for example, JP-A-54-162823 discloses
There is disclosed a steel mold having a two-layer film formed by fusion-bonding a film comprising a polyolefin compound (upper layer) and an adhesive polyolefin (lower layer) on the surface. However, JP
The steel formwork disclosed in the 4-162823 publication cannot be laminated at a construction site, requires a new production line, and after several uses, discards the polyolefin compound having reduced peeling performance. Has the disadvantage of being extremely difficult.

[0005] The concrete used is a curable concrete composition in which cement, sand and pebbles are mixed at a certain ratio and kneaded with water. A concrete structure or a concrete product is produced.However, the surface of the obtained concrete structure or the concrete product dries faster than the inside thereof, so that the surface of the concrete structure or the concrete product hardens or becomes harder. Since the accompanying shrinkage proceeds more rapidly, minute cracks and cracks are generated on the surface of the obtained concrete structure or concrete product, which not only impairs the appearance but also may lower the strength. Further, since the concrete is a cured product of a hydrophilic substance,
Waterproof performance is not enough.

Conventionally, in order to prevent the occurrence of cracks and cracks on the surface of the concrete structure or the concrete product, the hardenable concrete composition is added to a concrete hardening retarder for delaying hardening of concrete or a hardening agent for hardening concrete. The concrete shrinkage reducing agent which reduces shrinkage was mixed. However, in the method of mixing the concrete hardening retardant or the concrete shrinkage reducing agent into the entire hardenable concrete composition, it is necessary to mix a considerable amount of the cement with cement in order to exhibit the effect.

However, since most of the concrete hardening retarders and concrete shrinkage reducing agents have air entrainment properties, when the mixing amount is large, the strength of the obtained concrete structure or concrete product may be reduced. There is. Further, the agent comprising the concrete hardening retarder or the concrete shrinkage reducing agent necessary only for the surface layer of the obtained concrete structure or concrete product is mixed with the entire hardenable concrete composition. This not only increases the cost of the product, but also increases the cost required for mixing them.

[0008] Waterproofing agents used for imparting waterproofness to the surface of a concrete structure or a concrete product also have the same problems as the concrete hardening retarder or concrete shrinkage reducing agent.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above facts, and has as its object to provide a concrete having good mold release properties after hardening, and a hardening speed. Release sheet for concrete formwork that has no risk of causing cracks or cracks on the surface of the resulting concrete structure or concrete product due to imbalance in shrinkage rate during curing or curing, or that has been effectively waterproofed Is to provide.

[0010]

According to the first aspect of the present invention,
A concrete mold release sheet characterized in that an adhesive layer is laminated on one surface of an olefin resin film comprising 100 parts by weight of an olefin resin and 0.01 to 8 parts by weight of a concrete setting retarder. Is what you do.

The invention according to claim 2 is characterized in that 100 parts by weight of an olefin resin and a concrete shrinkage reducing agent of 0.01 to 100 parts by weight are used.
The gist of the present invention is a release sheet for a concrete form, characterized in that an adhesive layer is laminated on one surface of an olefin resin film composed of 8 parts by weight.

The invention according to claim 3 is characterized in that 100 parts by weight of an olefin resin and 0.01 to 0.01% of a concrete waterproofing agent are used.
The gist of the present invention is a release sheet for a concrete form, characterized in that an adhesive layer is laminated on one surface of an olefin resin film composed of 8 parts by weight.

The resin used for the polyolefin resin film used in the present invention is not particularly limited. For example, low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutene-1, poly (4 -Methylpentene-1) as well as copolymers containing other olefin monomers such as ethylene and propylene as main components and other α-olefins and other monomers copolymerizable therewith (for example, ethylene-propylene copolymer). A copolymer, an ethylene-butene-1 copolymer, an ethylene-hexene-1 copolymer, an ethylene-4-methylpentene-1 copolymer, an ethylene-octene-1 copolymer, etc.). These polyolefin resins may be used alone, or two or more kinds may be used in combination. In addition, an ultraviolet absorber, an antistatic agent, a plasticizer, a filler, and the like may be added to the resin as needed.

Examples of the ultraviolet absorber include salicylic acid esters, benzophenones, benzotriazoles, and cyanoacrylates.

Examples of the antistatic agent include nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, polyoxyethylene alkyl ether, polyoxyethylene allyl ether, polyoxyethylene alkylamine, and polyoxyethylene alkylamide. , Alkyl sulfonate, alkyl benzene sulfonate,
Examples include anionic antistatic agents such as alkyl sulfates and alkyl phosphates, and cationic antistatic agents such as quaternary ammonium nitrates.

As the plasticizer, phthalic acid-based plasticizers such as dioctyl phthalate, diisononyl phthalate, octyldecyl phthalate and diisodecyl phthalate, which are added for the purpose of imparting flexibility to the olefin resin film, Adipic acid plasticizers such as di-2-ethylhexyl adipate, diisononyl adipate, diisodecyl adipate, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate, tricresyl phosphate, trixylyl phosphate, and tributyl phosphate , Triphosphate-2
-Ethylhexyl, octyldiphenyl phosphate, chlorinated paraffin, chlorinated fatty acid esters, epoxy soybean oil and the like.

Examples of the filler include calcium carbonate, talc (basic magnesium silicate), kaolin (aluminum silicate), silica, titanium oxide and the like.

The concrete hardening retardant used in the first aspect of the present invention shifts from the polyolefin resin film to the hardenable concrete composition when the hardenable concrete composition is hardened, and delays the hardening reaction of the cement. Although it is not particularly limited as long as it has a function, for example, gluconic acid, tartaric acid,
Hydroxycarboxylic acids such as citric acid and malic acid, or salts thereof, ketocarboxylic acids such as pyruvic acid; polyhydric alcohols such as sorbitol and arabitol; sugars such as glucose, mannose and saccharose; sodium fluorosilicate and sodium iodide , Sodium humate,
Examples include sodium tannate, tannin, linseed oil and the like. Examples of commercially available products include "Disparite CR" (manufactured by Nippon Jikko Co., Ltd.) containing sodium gluconate as a main component.

The amount of the concrete hardening retardant added is
It is 0.01 to 8 parts by weight based on 100 parts by weight of the olefin resin. If the amount is less than 0.01 part by weight, the effect of retarding curing is hardly obtained. If the amount exceeds 8 parts by weight, the strength of the obtained release sheet for concrete formwork may be reduced.

The concrete shrinkage reducing agent used in the second aspect of the present invention transfers from the polyolefin resin film to the hardenable concrete composition when the hardenable concrete composition is hardened, and reduces the shrinkage of the hardening concrete during hardening. Although it is not particularly limited as long as it has a function of reducing, for example, polyethers such as polyethylene oxide and polypropylene oxide, glycol ethers such as 1,2-dimethoxyethane and 1,2-diethoxyethane And amino alcohols such as 2-amino-1-butanol. Examples of commercially available products include "HIVIGARD" (manufactured by Fujisawa Pharmaceutical Co., Ltd.) containing derivatives of glycol ether and amino alcohol as main components.

The amount of the concrete shrinkage reducing agent is as follows:
0.01 to 100 parts by weight of polyolefin resin
8 parts by weight. If the amount is less than 0.01 part by weight, the effect of reducing shrinkage is hardly obtained, and if it exceeds 8 parts by weight, the strength of the obtained release sheet for concrete formwork may be reduced.

The concrete waterproofing agent used in the third aspect of the present invention transfers from the polyolefin resin film to the curable concrete composition when the curable concrete composition is cured, and imparts waterproofness to the concrete after curing. It is not particularly limited as long as it has a function of imparting, for example, calcium chloride,
Inorganic waterproofing agents such as sodium silicate, silica powder, zirconium compound, etc .; (meth) acrylates such as ethyl acrylate, ethyl methacrylate, butyl acrylate and butyl methacrylate; and ethylene such as 2-imidazoricinone. Urea derivatives, pyridine-2-carboxylic acid,
Pyridine-2,3-dicarboxylic acid, pyridine-2,3
Organic waterproofing agents such as pyridinecarboxylic acids such as 4-tricarboxylic acid and salts thereof, long-chain aliphatic hydrocarbons, higher fatty acids, and paraffins and paraffin waxes composed of the same fatty acid salts. Examples of commercially available products include “Onoda NN” (manufactured by Chichibu Onoda Co.) containing paraffin as a main component.

The amount of the concrete waterproofing agent is 0.01 to 8 parts by weight based on 100 parts by weight of the olefin resin. If the amount is less than 0.01 parts by weight, the waterproof effect is hardly obtained, and if it exceeds 8 parts by weight, the strength of the obtained release sheet for concrete formwork may be reduced.

The method for forming the olefin resin into a sheet is not particularly limited, and examples thereof include a method by melt extrusion.

The release sheet for concrete formwork of the present invention can produce a hardened concrete having higher surface properties by using two or more of a concrete hardening retarder, a concrete shrinkage reducing agent and a concrete waterproofing agent. it can.

Examples of the pressure-sensitive adhesive used in the present invention include all those used as ordinary pressure-sensitive adhesive tapes or sheets. Acrylic pressure-sensitive adhesives are suitable for decorative applications in that they have good weather resistance. is there.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

(Example 1) Polypropylene resin (trade name "Polypropylene RB110", manufactured by Tokuyama Corporation) 100
A 200 μm-thick film was obtained by T-die extrusion molding of 0.05 parts by weight and 0.05 part by weight of a concrete hardening retarder (trade name “Disparite CR” manufactured by Nippon Jikko Co., Ltd., mainly containing sodium gluconate). One surface of the film was subjected to corona discharge treatment (degree of treatment: 45 dyne /
cm) and apply a pressure-sensitive adhesive (manufactured by Soken Chemical Co., Ltd.) on the corona discharge treated surface such that the thickness after drying becomes 40 μm.
A product name "SK1717") is applied and dried to laminate an adhesive layer, and then a release paper (manufactured by Kite Kagaku Co., Ltd., product name "SLK-80C") is pasted on the pressure-sensitive adhesive layer and temporarily bonded to a concrete mold. A release sheet for a frame was prepared.

Example 2 A release sheet for a concrete form was prepared in the same manner as in Example 1 except that the amount of the concrete retarder was changed from 0.05 part by weight to 1 part by weight.

Example 3 A release sheet for a concrete form was prepared in the same manner as in Example 1 except that the amount of the concrete retarder was changed from 0.05 parts by weight to 5 parts by weight.

(Comparative Example 1) A release sheet for a concrete formwork was produced in the same manner as in Example 1 except that no concrete hardening retardant was added.

(Comparative Example 2) A release agent (manufactured by Kobunshi Kagaku Kenkyusho Co., Ltd., trade name "Donox C-11M"), which is usually used as a coating-type release agent, was used for an iron plate for a formwork (manufactured by NS Pete Corporation) 10g / m ² on the product name “Metal Foam”)
To form an iron plate for a formwork that was applied at a coating amount of 1 and subjected to a release treatment.

Comparative Example 3 A release sheet for a concrete form was prepared in the same manner as in Example 1 except that the amount of the concrete retarder was changed from 0.05 parts by weight to 10 parts by weight.

(Example 4) 100 polypropylene resin (trade name "polypropylene RB110" manufactured by Tokuyama Corporation)
A 200-μm-thick film was formed by T-die extrusion molding of 0.05 parts by weight and 0.05 parts by weight of a concrete shrinkage reducing agent (trade name “HIVIGARD”, manufactured by Fujisawa Pharmaceutical Co., Ltd., mainly composed of a derivative of glycol ether and amino alcohol). And one surface of the obtained film was subjected to corona discharge treatment (degree of treatment: 45).
dyne / cm), a pressure-sensitive adhesive (manufactured by Soken Chemical Co., Ltd., trade name “SK1717”) is applied to the corona discharge treated surface so that the thickness after drying becomes 40 μm, and the adhesive layer is dried. Then, release paper (trade name “SLK-80C”, manufactured by Kite Chemical Co., Ltd.) was stuck and temporarily attached on the pressure-sensitive adhesive layer to prepare a release sheet for concrete formwork.

Example 5 A release sheet for a concrete form was prepared in the same manner as in Example 4 except that the amount of the concrete shrinkage reducing agent was changed from 0.05 part by weight to 1 part by weight.

Example 6 A release sheet for a concrete form was prepared in the same manner as in Example 4, except that the amount of the concrete shrinkage reducing agent was changed from 0.05 parts by weight to 5 parts by weight.

Comparative Example 4 A release sheet for a concrete form was prepared in the same manner as in Example 4 except that the amount of the concrete shrinkage reducing agent was changed from 0.05 parts by weight to 10 parts by weight.

(Example 7) Polypropylene resin (trade name "polypropylene RB110", manufactured by Tokuyama Corporation) 100
A 200 μm-thick film was formed by T-die extrusion molding of 0.05 parts by weight and 0.05 parts by weight of a concrete waterproofing agent (trade name “Onoda NN” manufactured by Chichibu Onoda Co., Ltd., mainly composed of paraffin). One surface is subjected to a corona discharge treatment (degree of treatment: 45 dyne / cm), and a pressure-sensitive adhesive (trade name “SK1717” manufactured by Soken Chemical Co., Ltd.) is applied to the corona discharge treated surface so that the thickness after drying becomes 40 μm. ) Is applied and dried to laminate the pressure-sensitive adhesive layer. Then, release paper (trade name “SLK-80” manufactured by Kite Chemical Co., Ltd.) is applied from above the pressure-sensitive adhesive layer.
C ") was temporarily attached to prepare a release sheet for a concrete formwork.

Example 8 A release sheet for a concrete form was prepared in the same manner as in Example 4 except that the amount of the concrete waterproofing agent was changed from 0.05 part by weight to 1 part by weight.

Example 9 A release sheet for a concrete form was produced in the same manner as in Example 4, except that the amount of the concrete waterproofing agent was changed from 0.05 parts by weight to 5 parts by weight.

Comparative Example 5 Except that the amount of the concrete waterproofing agent was changed from 0.05 parts by weight to 10 parts by weight,
A release sheet for a concrete formwork was produced in the same manner as in Example 4.

Examples 1 to 9, Comparative Examples 1 and 3
Peeling off the release paper of the release sheet for concrete form obtained in ~ 5, affixing each to an iron plate for form (manufactured by NS Pete Co., Ltd., trade name "Metal Foam"), combining these, width 160mm x height 600mm x length 10
A base concrete construction test frame of 00 mm was assembled, the ready-mixed concrete composition was poured, and the mixture was allowed to stand at 25 ° C. for 2 days to prepare a base concrete. or,
For Comparative Example 2, a basic concrete was produced in the same manner. However, for Comparative Examples 3 to 5, the release sheet was broken when the ready-mixed concrete composition was injected, and the following evaluations could not be made.

With respect to the foundation concrete obtained above, the releasability from the release sheet for the concrete form attached to the iron plate for the form, the presence or absence of cracks on the concrete surface, and the waterproofness of the concrete were measured by the following methods.
The results are shown in Tables 1 and 2.

Releasability of Concrete After Hardening The releasability between concrete and a release sheet for concrete formwork or an iron plate for formwork subjected to release treatment is as follows.
The presence or absence of concrete adhesion on the formwork surface after peeling was measured visually. There is virtually no concrete adhesion
Those that were good were described by the notation method of “good”, and those that had adhered were described by “not attached”.

The presence or absence of cracks on the concrete surface The presence or absence of cracks on the base concrete surface was visually measured.

Concrete waterproofness The obtained foundation concrete block is half-height (3
0cm) and left for 24 hours. After this,
After drying in an oven at 110 ° C. for 3 hours, the water absorption was calculated. Next, the amount of water absorption of the foundation concrete prepared without performing any treatment on the iron plate for formwork was similarly determined, and this was taken as 100.
And the water absorption ratio was calculated.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

The release sheet for a concrete form according to the present invention is constructed as described above, so that the releasability of the concrete form is extremely excellent, and at the same time, the curing speed and shrinkage at the time of curing are obtained. Due to the imbalance in speed, there is no possibility that cracks or cracks will be generated on the surface of the obtained concrete structure or concrete product, or water resistance is effectively imparted. In addition, the peeling sheet for concrete formwork can be easily peeled or replaced at the time of re-peeling due to the deterioration of the performance of the concrete formwork sheet. The work of sticking and re-peeling the release sheet for the formwork can be easily performed.

Claims (3)

[Claims] 1. A peeling method for a concrete formwork, wherein an adhesive layer is laminated on one surface of an olefin resin film comprising 100 parts by weight of an olefin resin and 0.01 to 8 parts by weight of a concrete hardening retardant. Sheet. 2. An exfoliation for concrete formwork, wherein an adhesive layer is laminated on one surface of an olefin resin film comprising 100 parts by weight of an olefin resin and 0.01 to 8 parts by weight of a concrete shrinkage reducing agent. Sheet. 3. A release sheet for a concrete formwork, wherein an adhesive layer is laminated on one surface of an olefin resin film comprising 100 parts by weight of an olefin resin and 0.01 to 8 parts by weight of a concrete waterproofing agent. .