JP3166169B2 - Method of protecting cementitious substrate and surface-protected cementitious substrate - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for protecting a cementitious substrate and a surface-protected cementitious substrate.
The present invention relates to a method for protecting a cementitious substrate having excellent chemical resistance and durability and a surface-protected cementitious substrate.

(Prior art) Portland cement concrete and cement mortar are widely used in the fields of civil engineering and construction as construction materials having excellent durability. However, since the surface of a structure using these is very often exposed to wind and rain, it is often desirable to protect the exposed surface with a coating material or a resin composition. For example, concrete reinforced with steel is used for bridge decks, building, roads, etc., but if the surface is exposed to rainwater, especially acid rain for a long period of time, these will penetrate into the concrete and become reinforced steel. Since rust is generated in the concrete, cracks are generated in the concrete due to the expansion of the rust, and damage to the structure is increased, which may lead to fatal deterioration. Concrete plates in chemical factories and plants are affected by various chemicals and are severely damaged. Concrete pipes such as hyum pipes are often used as sewage pipes. Because of this, concrete pipes are becoming severely damaged.

Various methods have been studied to protect cementitious substrates such as concrete from the rainwater (acid rain), sewage, chemicals, and the like. Adhesion and permeability are improved by mixing a synthetic polymer emulsion into cement base or cement mortar. Methods for improving air quality, water permeability, and the like are known. For example, a method for improving the adhesiveness of cement mortar is disclosed in
As disclosed in JP-A-18757, there is a method in which a synthetic polymer emulsion is previously applied to a base to enhance the adhesiveness of a mortar. However, with such a method, it is difficult to improve the essential porous structure to be non-porous, even though the air permeability and water permeability of the cement paste and cement mortar can be reduced.

In addition, although coating of a cementitious substrate with various synthetic resins has been studied, there is a problem that adhesion to the cementitious substrate is poor. For example, protection with urethane-based paints causes problems in the working environment because the resin is a solvent type, and poor adhesion to concrete base materials due to insufficient impregnation into concrete base materials because the resin itself is a polymer. There is.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art, improve the adhesion between the protective film and the concrete body, and prevent the penetration of rainwater, sewage, and the like. It is an object of the present invention to provide a method of protecting a cementitious substrate and a cementitious substrate whose surface is protected.

(Means for Solving the Problems) The present invention relates to an unsaturated dibasic acid and / or an acid anhydride thereof, a polyhydric alcohol, and if necessary, a polybasic acid obtained by a condensation reaction. After coating and curing a composition containing polyester and a dicyclopentadiene derivative represented by the following formula (I) on a cementitious base material, a thermosetting resin composition is coated and / or laminated with a reinforcing material on the cured product. And a method for protecting a cementitious substrate characterized by curing, and after applying and curing the above composition on a cementitious substrate, applying a thermosetting resin composition on the cured product and / or a reinforcing material. The invention relates to a laminated and cured surface protected cementitious substrate.

Wherein R ₁ is an alkylene glycol residue of 2 to 12 carbon atoms or at least two alkylene chains having 4 to 12 carbon atoms and linked by at least one oxygen atom, The alkylene chain represents an oxaalkylene glycol residue having at least 2 carbon atoms, and R ₂ represents a hydrogen or a methyl group.] The unsaturated polyester used in the present invention is not particularly limited and may be α, β- A polyester obtained by reacting an unsaturated dibasic acid and / or an acid anhydride thereof, a polyhydric alcohol and, if necessary, a polybasic acid by a condensation reaction is used.

Examples of the α, β-unsaturated dibasic acid and / or acid anhydride include maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride and the like. These may be used in combination of two or more.

Examples of polyhydric alcohols include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,6-hexanediol, and neopentyl glycol; and trihydric alcohols such as glycerin and trimethylolpropane. Alcohol, tetrahydric alcohols such as pentaerythritol and the like can be used. These may be used in combination of two or more.

The polybasic acids used as needed include phthalic acid, phthalic anhydride, succinic acid, azelaic acid, adipic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, citraconic acid, isophthalic acid, terephthalic acid Acid and trimellitic anhydride.

Further, as a polybasic acid used as needed, a dibasic acid having 12 or more carbon atoms can be used. Specific examples thereof include todecandioic acid, commercially available SLB-12 manufactured by Okamura Oil Co., Ltd., and ULB-20 which is a mixture of isomers of unsaturated dibasic acids having 16 carbon atoms (also Okamura Oil Co., Ltd.). )
SL-, a mixture mainly composed of saturated dibasic acids having 20 carbon atoms.
20 (also manufactured by Okamura Oil Co., Ltd.), and tall oil fatty acids, also known as dimer acids having 36 carbon atoms, are used as raw materials.
And quantified fatty acids. Commercial products of this dimer acid include Enpol 1022, Enpol 1024 (Emery), Versa Dime 216, Versa Dime 288 (Daiichi General), Harari Dimer # 200 (Harima Chemical Co., Ltd.)
Manufactured).

 These may be used in combination of two or more.

The unsaturated polyester used in the present invention is a known compound, and the method for producing the unsaturated polyester by reacting the above-mentioned acid component and alcohol component is mainly carried out by advancing a condensation reaction. The process proceeds by desorbing water generated when the components react to the outside of the system.

A general apparatus and reaction conditions for performing this reaction will be described.

The reaction device is made of glass, stainless steel, etc.
A stirring device, a fractionating device for preventing the distillation of alcohol components due to azeotropic distillation of water and alcohol components, a heating device for increasing the temperature of the reaction system, a temperature control circuit for this heating device, and a blowing device for nitrogen gas or the like are provided. It is preferable to use a reactor provided.

The reaction conditions are preferably such that the reaction temperature is 150 ° C. or higher.

In order to prevent a side reaction due to oxidation, the reaction is preferably performed while passing an inert gas such as nitrogen or carbon dioxide.

The reaction proceeds by heating the system in which the acid component and the alcohol component are mixed to remove low-molecular compounds such as condensed water formed outside the system. This is preferably carried out by natural distillation or by passing through an inert gas. This is performed by vacuum distillation.

Further, in order to promote the distillation of the condensed water, a solvent such as toluene or xylene can be added to the system as an azeotropic component to perform natural distillation.

In general, the progress of the reaction can be known by measuring the amount of distillate generated by the reaction, quantifying the terminal functional group, measuring the viscosity of the reaction system, and the like.

In the reaction, a polymerization inhibitor such as hydroquinone, parabenzoquinone, and hydroquinone monomethyl ether may be used.

In the present invention, the dicyclopentadiene derivatives represented by the above formula (I) are used, but these are already known compounds. The dicyclopentadiene derivative represented by the formula (I) is a group having an ethylenically unsaturated double bond at the 8- or 9-position of the dicyclopentadiene group, Are combined. Where R ₁ is a carbon atom of 2 to 12
Alkylene glycol residues or oxaalkylene glycol residues having from 4 to 12 carbon atoms and having at least two alkylene chains, wherein the alkylene chain has at least two carbon atoms; ₂ means hydrogen or a methyl group.

Examples of the dicyclopentadiene derivative include dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyloxypropyl acrylate, and dicyclopentenyloxypropyl methacrylate. As described in JP-B-61-43337, these compounds are prepared by subjecting dicyclopentadiene to an addition reaction with alkylene glycol or oxaalkylene glycol, and forming the resulting alkylene glycol monodicyclopentenyl ether or oxaalkylene glycol monodiene. It can be produced by subjecting cyclopentenyl ether to a condensation reaction with methacrylic acid or a transesterification reaction with methyl methacrylate. This methacrylic acid or methyl methacrylate can be replaced with acrylic acid or methyl acrylate. Also, as described in JP-A-57-200331, it can be produced by an addition reaction of alkylene glycol monoacrylate or alkylene glycol monomethacrylate with dicyclopentadiene.

The proportion of the dicyclopentadiene derivative represented by the formula (I) should be in the range of 60 to 1900 parts by weight with respect to 100 parts by weight of the unsaturated polyester from the viewpoint of impregnation of the composition with the cementitious base material. Is preferred.

When the composition containing the unsaturated polyester thus obtained and the dicyclopentadiene derivative represented by the formula (I) is cured, as a reaction catalyst, for example, benzoyl peroxide, methyl ethyl ketone peroxide, ditertiary butyl peroxide Organic peroxides such as oxide and cumene hydroperoxide are used. Further, as the polymerization accelerator, polyvalent metal salts such as cobalt naphthenate and cobalt octenoate, and aromatic amines such as dimethylaniline can be used.

The curing temperature is usually -20 to 160 ° C, and it is preferable to adjust the pot life of the composition by the addition amount of a reaction accelerator or the use of a polymerization inhibitor such as hydroquinone depending on the temperature difference between summer and winter.

In the present invention, the composition containing the unsaturated polyester and the dicyclopentadiene derivative represented by the formula (I) is applied to a cementitious base material and cured, and then the thermosetting resin composition is applied on the cured product. And / or cured with the reinforcement.

The cement base material in the present invention is cement concrete, cement mortar, slate, or the like.

As the thermosetting resin composition to be applied or laminated, an epoxy resin composition, an unsaturated polyester resin composition, a solventless urethane paint and the like are used. Among these, a radical polymerizable thermosetting resin composition is preferable, and an unsaturated polyester resin composition is more preferable because it has low viscosity, excellent workability, and balance with other properties.

Further, as the reinforcing material, glass mat, glass cloth, vinylon fiber, polyester fiber, a fiber cloth thereof, or the like is used.

The application of the composition and the thermosetting resin composition in the present invention can be performed by a method of applying a normal paint such as spraying or brushing, and the method of laminating the thermosetting resin together with the reinforcing material is also a usual method. Done in a way.

(Examples) Hereinafter, the present invention will be described in more detail with reference to examples. In addition,
In the examples, parts and% mean parts by weight and% by weight.

Synthesis Example 1 Synthesis of unsaturated polyester (A) 1.5 mol of maleic anhydride, 0.5 mol of adipic acid, 1.6 mol of neopentyl glycol and 0.6 mol of propylene glycol were mixed and heated to 200 ° C. in a nitrogen gas stream for 4 hours.
Then, the reaction was completed when the acid value reached 15 in 15 hours, and an unsaturated polyester (A) was obtained.

Synthesis Example 2 Synthesis of unsaturated polyester (B) 1.6 mol of maleic anhydride, 0.4 mol of dimer acid (manufactured by Harima Kasei Kogyo KK, Haridimer 200), 1.2 mol of diethylene glycol and 0.9 mol of propylene glycol were mixed in a stream of nitrogen gas. The temperature was raised to 200 ° C. in 4 hours.

Then, the reaction was completed when the acid value reached 20 in 10 hours, and an unsaturated polyester (B) was obtained.

Synthesis Example 3 Synthesis of dicyclopentenyloxyethyl methacrylate 660 parts of dicyclopentadiene, 160 of ethylene glycol
And 4 parts of p-toluenesulfonic acid were reacted at 120 ° C for 4 hours.
And 4 parts of p-toluenesulfonic acid, and the mixture was reacted at 100 ° C. for 5 hours while distilling off water. The obtained reaction product was neutralized with magnesium oxide. The reaction product was washed with water and purified by distillation under reduced pressure.

Example 1 15 parts of the unsaturated polyester (A) synthesized in Synthesis Example 1,
In a composition obtained by mixing 85 parts of dicyclopentenyloxyethyl methacrylate synthesized in Synthesis Example 3, 2 parts of cobalt naphthenate (metal content: 6%) and 4 parts of cumene hydroperoxide are dissolved, and the solution is determined according to JIS A 5304. It was applied to a concrete sidewalk board to a thickness of 400 g / m ² . After the composition was cured at room temperature, a resin composition obtained by dissolving 1 part of 55% methyl ethyl ketone peroxide in 100 parts of Polyset 5595APR (trade name, manufactured by Hitachi Chemical Co., Ltd., unsaturated polyester resin) and glass mat ( FE
Using two M-450 (trade name, manufactured by Fuji Fiberglass Co., Ltd.), a 2 mm thick FRP was laminated. After curing the FRP at room temperature, a square iron piece with a side of 40 mm was bonded to the surface of the FRP with an epoxy resin adhesive (Konishi Co., Ltd., bond kit set). A notch was reached, and the adhesive strength was measured using a Kenken-type adhesive strength tester. The strength at the time of the cohesive failure of the protective film from the concrete sidewalk board was 28 kg f / cm ² .

Example 2 15 parts of the unsaturated polyester (B) synthesized in Synthesis Example 2,
In a composition prepared by mixing 85 parts of dicyclopentenyloxyethyl methacrylate synthesized in Synthesis Example 3, 2 parts of cobalt naphthenate (metal content: 6%) and 4 parts of cumene hydroperoxide were dissolved, and the same as in Example 1 was performed. Was applied on a concrete sidewalk board, and FRP was laminated and cured in the same manner as in Example 1 to measure the adhesive strength. The strength at the time of the cohesive failure of the protective film from the concrete sidewalk board was 25 kg f / cm ² .

Comparative Example An FRP was laminated and cured in the same manner as in Example 1 except that the composition of the unsaturated polyester (A) and dicyclopentenyloxyethyl methacrylate was not used, and the adhesive force was measured. . Protective film occurs peeling at the interface between the FRP and concrete walkways plate, the strength at that time was found to be 4kg f / cm ^2.

(Effect of the Invention) According to the present invention, the adhesive strength between the protective film and the cementitious substrate can be improved, and the penetration of rainwater or sewage can be prevented. Chemical properties and durability can be improved.

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Claims (2)

(57) [Claims] 1. An unsaturated polyester obtained by subjecting an α, β-unsaturated dibasic acid and / or an acid anhydride thereof, a polyhydric alcohol and, if necessary, a polybasic acid to a condensation reaction, and an unsaturated polyester represented by the following formula (I): After coating and curing a composition containing the represented dicyclopentadiene derivative on a cementitious base material, a thermosetting resin composition is coated and / or laminated with a reinforcing material on the cured product and cured. How to protect cementitious substrates. Wherein R ₁ is an alkylene glycol residue of 2 to 12 carbon atoms or at least two alkylene chains having 4 to 12 carbon atoms and linked by at least one oxygen atom, The alkylene chain represents an oxaalkylene glycol residue having at least 2 carbon atoms, and R ₂ represents hydrogen or a methyl group] 2. The composition according to claim 1, which is applied to a cementitious substrate and cured, and then a thermosetting resin composition is applied and / or laminated with a reinforcing material on the cured product to cure the surface. Cementitious substrate.