JPH0245961B2 - KONKURIITOCHIKOMYOKATAWAKURIKEIZAI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold release agent for concrete pouring, particularly to a mold release agent containing a novel fluorine-containing polymer having a good mold release effect.

Many concrete products are used in various buildings and buildings, and they come in a variety of shapes. These come in a wide variety of forms, including those that are constructed on-site, or those that are pre-configured in a factory to a predetermined shape or size and then assembled on-site. In any case, a large number of molds of various shapes are used to manufacture these structures.

When using these molds, a mold release agent is usually used, which may inhibit the surface condition of the manufactured product, or
Alternatively, when the mold is used repeatedly, the condition of the molding surface of the mold is maintained in good condition.

Conventionally, as these mold release agents, for example, various vegetable oils, animal oils, mineral oils, paraffin waxes, spindle oils, acrylic resins, epoxy resins, etc. have been proposed and actually used. However, the majority of these materials require application to the surface of the mold each time molding is performed, or there are problems with mold releasability, or there are problems with the material of the mold used, especially when using synthetic resin molds. In particular, the range of selection of the mold release agent is not always satisfactory, as the range of selection of the mold release agent is subject to considerable restrictions, such as partially dissolving or deforming the mold release agent, or partially dissolving the mold release agent into the mold.

In view of these points, the present inventors have found that when molding a concrete structure using formwork materials, particularly various synthetic resin formworks, the releasability thereof is good;
In addition, as a result of various research and studies aimed at finding a mold release agent that does not leave any concrete residue on the formwork, can be stably used repeatedly after a single treatment, and does not damage the formwork itself, we have found that: It has been found that the above object can be achieved by using a certain fluorine-containing polymer.

Thus, the present invention has a hardening site and an intrinsic viscosity measured at 30°C in tetrahydrofuran of 0.05 to
The present invention provides a mold release agent for concrete pouring, which contains a solvent-soluble fluorine-containing polymer of 2.0 dl/g.

The fluorine-containing polymer used in the present invention must first have a curing site. If there are no hardened areas, the durability is poor and unsuitable when applied to the mold surface. As a hardened part,
It is selected from hydroxyl group, epoxy group, carboxyl group, acid amide group, ester group, unsaturated bond, active hydrogen, and halogen, and it is necessary to have at least one of these.

Also, if the intrinsic viscosity is too low, the mechanical strength will be insufficient when applied to the mold surface, and if it is too high, the solution concentration will have to be lowered due to viscosity, and if it is insoluble in solvents. Both are unsuitable because it is difficult to uniformly apply them to the mold surface.

As the fluorine-containing polymer used in the present invention, either an addition polymer type or a condensation polymer type can be used. Examples of addition polymer systems include addition polymers or addition copolymers of fluorine-containing unsaturated compounds; examples of condensation polymer systems include epoxy resins having a fluorine-containing difunctional group;
Alternatively, examples include condensates of fluorine-containing diols, dibasic acids, anhydrides, diisocyanates, etc., which form ester bonds, urethane bonds, urea bonds, etc.

These fluorine-containing polymers are preferably addition polymers such as copolymers of fluoroolefin and hydrocarbon vinyl ethers from the viewpoint of durability, mechanical strength, releasability from concrete, and the like.

The fluoroolefin-vinyl ether copolymer that can be suitably used in the present invention preferably contains 30 to 70 mol% and 70 to 30 mol% of units based on fluoroolefin and vinyl ether, respectively, and the preferred fluoroolefin component is Examples include tetrafluoroolefin and chlorotrifluoroethylene, and preferred vinyl ether components include alkyl vinyl ethers having a _C2-8 linear, _branched , or cyclic alkyl group. In addition, as the comonomer that provides a curing site in such a copolymer, functional group-containing vinyl ethers such as hydroxyalkyl vinyl ether or glycidyl vinyl ether are preferred.

The above copolymers can be produced by causing a copolymerization reaction by allowing a polymerization initiator or a polymerization initiation source such as ionizing radiation to act on a monomer mixture of a predetermined ratio in the presence or absence of a polymerization medium. be.

A curing agent such as a polyfunctional compound having reactivity with the curing site of the fluorine-containing polymer used in the present invention is 0.1 to 100 parts by weight, based on 100 parts by weight of the polymer.
Preferably, it is suitably blended in a proportion of 0.5 to 50 parts by weight.

Furthermore, in addition to this, a curing aid or curing catalyst can be appropriately blended. For example, for a fluorine-containing polymer whose curing site is a hydroxyl group, diisocyanate or titanium alkoxide can be preferably used as a curing agent if the fluorine-containing polymer is to be cured at room temperature. In addition, if the fluorine-containing polymer is to be heat-cured as desired, melamine curing agents, urea resin curing agents, polybasic acid curing agents, etc. used in ordinary thermosetting acrylic paints can be used as curing agents. It is valid. Here, examples of the melamine curing agent include butylated melamine, methylated melamine, epoxy-modified melamine, etc., and those having various degrees of modification from 0 to 6 can be used, and the degree of self-condensation can also be selected as appropriate. Examples of the urea resin include methylated urea, butylated urea, and the like.

Further, as the polybasic acid curing agent, long-chain aliphatic dicarboxylic acids, aromatic polycarboxylic acids or their anhydrides, blocked polyvalent isocyanates, etc. are used.

When using Melamis or urea hardening agent,
Curing can also be accelerated by the addition of acidic catalysts. As another example, when the curing site of the fluorine-containing polymer is an epoxy group, amines, carboxylic acids, phenols, alcohols, etc. are effective as curing agents. Aromatic diols are useful as curing aids. It is desirable to select such a curing system appropriately depending on the type of substrate.

The fluorine-containing polymer used as a mold release agent in the present invention can be used alone, but it can also be used in combination with titanium white, color pigments such as iron oxides, extender pigments such as calcium carbonate, solvents such as xylene and toluene, etc. A curing agent or the like can be used in combination, and this may be preferable in terms of cost and operation. When using other components in combination like this, the amount of fluorine-containing polymer to be used is strictly determined by the type of other components used, but in general, it is appropriate to use 20 to 60% by weight of the fluorine-containing polymer. It is.

In fact, when using other components such as those mentioned above, for example, 20 to 60% by weight of a fluorine-containing polymer and 40 to 60% by weight of a pigment.
It is practical to use about 0% by weight, about 40 to 20% by weight of the solvent, and about 3 to 12% by weight of the curing agent. When these other components are used together, there is no particular restriction on the method of mixing them with the fluorine-containing polymer, and they may be mixed by any known means as appropriate.

Furthermore, there are no particular restrictions on the material of the formwork for concrete pouring to which the mold release agent of the present invention is applied; for example, various plastics and materials reinforced with fiber reinforcement such as glass fiber, metals, water, etc. It is widely applied to formwork made of various materials such as hard inorganic materials and those reinforced with reinforcing materials such as fibers.

The concrete material to be used is not particularly limited, and various cements and mixtures thereof with other materials such as gypsum, lime, and resin, as well as aggregates, reinforcing materials, etc., may be used.

Next, the present invention will be explained by examples.

Example 1 The molar ratio of chlorotrifluoroethylene, cyclohexyl vinyl ether, and hydroxybutyl vinyl ether is 50, 40, and 10%, the hydroxyl value is 50 mgKOH/g, and the intrinsic viscosity measured at 30°C in tetrahydrofuran is 0.23 dl/g. Add 46% by weight of a fluorine-containing polymer, 50% by weight of a 50/50 mixed solvent of xylene/methyl isobutyl ketone, and 4% by weight of an isocyanate hardener, mix uniformly, and apply to the inner surface of a urethane resin mold. It was dried at ~30°C for 3 days. Concrete consisting of 1 part of Bortland cement, 2 parts of sand, 3 parts of gravel, and 0.6 parts by weight of water was poured into the resulting form and cured at 20 to 30°C for 7 days.

The hardened concrete was easily released from the formwork, and the resulting concrete surface was smooth and free of any deposits, and the release agent applied inside the formwork completely adhered to the mold surface. It was still there.

Example 2 Fluorine-containing copolymer 40 in which the molar ratio of chlorotrifluoroethylene, cyclohexyl vinyl ether, and glycidyl vinyl ether is 52, 10, and 38%, and the intrinsic viscosity measured at 30°C in tetrahydrofuran is 0.19 dl/g. % by weight, 40% by weight of xylene/methyl isobutyl ketone 50/50 mixed solvent, 2% by weight of dimethylcyclohexylamine hydrochloride and 18% by weight of titanium white, and the mixed solution was uniformly coated on the same mold as in Example 1 and dried. However, as a result of molding concrete in the same manner, the same results as in Example 1 were obtained.

Claims (1)

[Claims] 1. Has a hardening site and is heated at 30°C in tetrahydrofuran.
1. A mold release agent for concrete pouring, comprising a solvent-soluble fluorine-containing polymer having an intrinsic viscosity of 0.05 to 2.0 dl/g. 2. The mold release agent according to claim 1, wherein the curing site is at least one selected from hydroxyl group, epoxy group, carboxyl group, acid amide group, ester group, unsaturated bond, active hydrogen, and halogen. 3. The fluorine-containing polymer is a copolymer of a fluoroolefin and a hydrocarbon vinyl ether, containing 30 to 70 mol% and 70 to 30 mol% of units based on the fluoroolefin and vinyl ether, respectively, and containing hydroxyalkyl vinyl ether or hydroxyalkyl vinyl ether. The mold release agent according to claim 1, which contains units based on glycidyl vinyl ether in a proportion of 30 mol% or less.