JPH0154387B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides an emulsion-based baking type that has good workability and forms a durable and excellent rust-preventing coating film on the object to be treated by baking, and is particularly useful for rust-preventing concrete reinforcing bars. This relates to rust preventives. [Prior art] In general, reinforcing bars used in concrete are used in two ways: one is assembled on-site as a reinforcement for concrete structures, and the other is used in factories as a reinforcement for precast boards and lightweight aerated concrete.
There are various usage modes. In any of these usage modes, problems arise due to rusting of reinforcing bars for concrete. In other words, when reinforcing bars are used on-site, they are exposed to wind, rain and sunlight until they are buried in concrete, causing rust, and if concrete is poured in this condition, the reinforcing function of the reinforcing bars is lost. It is not fully demonstrated. Recently, sea sand is often used as sand for concrete, so even after being buried in concrete, the salt contained in the sea sand corrodes the reinforcing bars, which significantly reduces the durability of concrete structures. There are problems such as a decline. Furthermore, in concrete structures built near the coast, the penetration of salt causes corrosion of the reinforcing bars, resulting in a phenomenon in which the strength of the concrete structures decreases in a short period of time, leading to their destruction. On the other hand, even when used on a factory line,
Especially when used for lightweight cellular concrete, the reinforcing bars used as reinforcing materials are extremely susceptible to rusting because the concrete for the framework is neutralized rather than alkaline and is porous, allowing water and air to permeate easily. It is in an easy condition. As described above, rusting of reinforcing bars for concrete has become a major problem, and there is a strong desire to develop an effective rust prevention method. Therefore, various rust prevention methods for concrete reinforcing bars have been proposed in recent years. These rust prevention methods can be roughly divided into two methods: mixing synthetic resin, etc. and cement, etc., and applying a cement-based rust preventive agent made from this mixture to the reinforcing bars; A method of forming a rust-preventing coating on the surface of reinforcing bars using a water-based anti-rust paint made of rubber latex, silica powder, lime, etc., or an aqueous emulsion made of synthetic resin, talc, rock wool, etc. There are four types of methods: 1, a method of baking epoxy resin powder onto the surface of reinforcing bars; A specific example of the above method is
2843, Special Publication No. 36-23879, and Special Publication No. 15062 of 1972, there are various methods of adding methyl cellulose to Portland cement, adding various latexes, and methods of applying these. As seen in No. 58-1698 and Japanese Unexamined Patent Publication No. 56-164048, there is a method of preparing a cement-based rust preventive agent using a synthetic resin emulsion and quick-hardening cement, and applying the same. However, these proposed methods have the problem that the cement-based rust preventive has a pot life, which limits the period of use, and the rust preventive coating is brittle and may peel off when the painted reinforcing bars are transported. do. Cracks occur due to shrinkage of the paint film. There are concerns about the rust prevention ability because it easily decreases due to phenomena such as pinholes forming in the paint film, and there are also problems such as the rust prevention being drastically reduced when the cement is neutralized. As a result, the reliability is not completely satisfactory. A specific example of the above method is a method in which a polystyrene resin solution paint is applied to the surface of the reinforcing steel to form a dense coating film, as disclosed in Japanese Patent Publication No. 1581/1981. This method provides excellent rust prevention properties, but since it uses solvents, it poses a risk of deterioration of the working environment, fire, and explosion, and is expected to cause problems such as air pollution. There are some drawbacks. A specific example of the above method is as shown in Japanese Patent Application Laid-Open No. 50-97617, in which a water-based rust-preventive paint is made by adding and mixing silica powder, lime, etc. to rubber latex, and this creates a rust-preventive coating. There is a method of forming a copolymer consisting of an unsaturated carboxylic acid, an alkyl acrylate, a vinyl monomer, and an aqueous emulsion consisting of talc, rock wool, etc., as shown in JP-A-52-136229. . However, the rust-preventing coatings formed by these methods are inferior in density to those of the organic solvent-based coatings, and therefore have the disadvantage that their rust-preventing properties do not reach a practical level.
A specific example of the above method includes baking and painting epoxy resin powder onto reinforcing bars. This method forms an extremely tough anti-corrosion coating, making it the most reliable of the anti-corrosion treatment methods, but it is expensive and has drawbacks in terms of adhesion of the coating to concrete. [Problems to be solved by the invention] As described above, the various methods proposed for the purpose of rust prevention of concrete reinforcing bars each have their own drawbacks, and a satisfactory rust prevention method has not been obtained. That is the reality. This invention was made in view of these circumstances, and focused on the advantages of water-based emulsion-based rust preventives, such as good workability, storage stability (pot life), and economic efficiency. By improving the lack of density of the film and improving the adhesion of the film to the object to be treated, it is possible to form an excellent and durable anti-rust coating on objects to be treated such as reinforcing bars. The purpose of this invention is to provide an aqueous emulsion type rust preventive agent. [Means for Solving the Problems] In order to achieve the above object, the present invention uses an acrylic copolymer, a styrene-acrylic copolymer,
The main component is at least one polymer selected from the group consisting of synthetic rubber latex, natural rubber latex, ethylene-vinyl acetate copolymer, vinyl acetate-versatic acid vinyl ester copolymer, and vinyl chloride-vinylidene chloride copolymer. The composition is such that at least component (A) of the following components (A) and (B) is blended into an aqueous polymer emulsion. (A) Polystyrene, polyacrylonitrile, acrylonitrile-styrene copolymer, polymethyl methacrylate, styrene-methyl methacrylate copolymer, polypropylene, polyethylene, phenolic resin initial condensate, uncured epoxy resin, rosin, petroleum resin, and room temperature at least one compound selected from the group consisting of solid bituminous substances, at a temperature at least 10°C higher than the minimum film forming temperature of the above emulsion and from 40 to 40°C;
A heat-melting organic filler made of a compound having a melting point or softening point within the temperature range of 250°C. (B) Bituminous emulsion. That is, the emulsion-based baking type rust preventive agent of the present invention is essentially a water-based emulsion-based rust preventive agent, but whereas conventional water-based emulsion-based rust preventive agents form a film through the process of coating and drying. ,
The process involves not only coating and pre-drying but also baking. Then, during the above baking,
The above component (A) of the present invention melts at the baking temperature and fills the pores or voids in the polymer aqueous emulsion coating film produced in the pre-drying step to densify the coating film. This is the greatest feature of this invention. In the emulsion-based baking type rust preventive agent of the present invention, the polymer of the polymer aqueous emulsion and the heat-melting organic filler are combined in order to withstand the heat during baking and to ensure mutual compatibility. limited to specific things. As described above, according to the present invention, the above-mentioned aqueous polymer emulsion coating film and the above-mentioned (A) component filling the pores provide the surface of the treated object with properties comparable to or better than those of organic solvent-based coatings. This results in the formation of a dense, highly durable anti-corrosion baked coating with low water permeability and air permeability, which exhibits excellent anti-corrosion effects on objects to be treated such as reinforcing bars. In this case, the heat-melting organic filler not only fills the pores of the aqueous polymer emulsion coating, but also melts and intervenes between the emulsion coating and the object to be treated, such as reinforcing steel, so that the two adhere closely together. It acts to improve sex. In particular, we have made lightweight concrete reinforcing bars coated with the emulsion-based baking type rust preventive agent of this invention and formed with a polymer aqueous emulsion coating (containing a heat-melting organic filler) on the surface through a pre-drying coating process. foam concrete
When used as reinforcing bars in the production of Autoclaved Light-weight Concrete (hereinafter abbreviated as "ALC"), the heat generated when the reinforced concrete is placed in an autoclave and heat-treated at 180°C, 10 atm, and 10 hours is reduced. Since it can be used as heat for drying in the baking process, it is possible to form a dense anti-corrosion baking coating with sufficient strength on concrete reinforcing bars without a special baking process. At this time, the heat-melting organic filler in the emulsion coating film melts during heating in the autoclave treatment and exerts a reinforcing effect on the emulsion coating film, and also melts between the anti-rust baking coating film and the concrete structure. By intervening, the effect of improving the adhesion between the reinforcing bars and the concrete frame can be exerted, thereby significantly increasing the effectiveness of the reinforcing bars as a concrete reinforcing material. Further, a bituminous emulsion (component B) may be blended with the above-mentioned component A in the emulsion-based baking type rust preventive agent of the present invention. The emulsion-based baking type rust preventive agent containing the above bituminous emulsion is able to exhibit better adhesion to reinforcing steel after pouring concrete, even without special heat treatment, compared to those without bituminous emulsion. become. For example, when reinforcing bars are baked with the rust preventive agent of the present invention in advance and assembled and used on-site, heating is not performed after concrete casting as in the production of Example ALC. It also exhibits the effect of significantly increasing the adhesion between the reinforcing bars and the concrete frame, and at the same time further increasing the adhesion between the reinforcing bars and the rust-preventing coating of the present invention.
Although it is not clear why the bituminous emulsion exhibits the above-mentioned effect, it is presumed that the tackiness of the bituminous emulsion contributes in some way. The aqueous polymeric emulsion having the ability to form a coating is not particularly limited, and any aqueous polymeric emulsion that can withstand the heat during baking and has the ability to form a coating can be used. It is. Preferred are aqueous synthetic resin emulsions conventionally used in emulsion paints, such as aqueous acrylic resin emulsions and aqueous vinyl acetate resin emulsions, and rubber latexes can also be suitably used. The above polymer aqueous emulsion has a minimum film forming temperature of 50
℃ or less, especially 20℃ or less. If the minimum film forming temperature exceeds 50℃, high temperatures are required for film formation, and the resulting coating film may have blisters that are difficult to repair during the film formation process. Because it may cause coarse pores,
It is appropriate to refrain from its use. especially,
With anticorrosion agents for concrete reinforcing bars, the resulting coating film is in contact with the alkaline components of concrete for a long period of time, so
It is desirable to use an aqueous polymeric emulsion that has the ability to form a coating that is resistant to decomposition even when in contact with an alkali component for a long period of time. From the above viewpoint, representative examples of suitable polymeric aqueous emulsions are as follows:
It is as follows. Methyl methacrylate/butyl acrylate [65/35 to 25/75 (molar ratio, same below)] copolymer, methyl methacrylate/2-ethylhexyl acrylate (80/20 to 40/60) copolymer, etc. Aqueous emulsion of acrylic copolymer, styrene/butyl acrylate (65/35~25/
75) Copolymers, aqueous emulsions of styrene-acrylic copolymers such as styrene/2-ethylhexyl acrylate (80/20 to 40/60) copolymers, styrene-butadiene rubber latex, acrylonitrile rubber latex, butyl rubber synthetic rubber latex or natural rubber latex such as chloroprene rubber latex, methylbutadiene methacrylate rubber latex, ethylene/vinyl acetate (35/65 to 65/35) copolymer emulsion, vinyl acetate/vinyl versatility Examples include aqueous emulsions of ester (90/10 to 50/50) copolymers and aqueous emulsions of vinyl chloride/vinylidene chloride copolymers. Each of the above-exemplified aqueous polymer emulsions exhibits excellent effects, but what is more preferable is based on the molecular structure of each of the above-exemplified polymers, and cross-linked with carboxyl groups, glycidyl groups, methylol groups, etc. It is an aqueous emulsion containing a polymer into which a reactive group has been introduced. In this invention, the aqueous polymer emulsion includes both those without and those with a crosslinkable group introduced therein. A specific example of those into which a group capable of crosslinking reaction has been introduced is a polymer aqueous emulsion obtained by copolymerizing a crosslinking reactive monomer such as acrylic acid in a proportion of about 10 mol % or less. When such an aqueous emulsion of a crosslinkable polymer is used in combination with a crosslinkable heat-melting organic filler as described later, it forms a rust-preventing coating film with even better density and adhesion. This makes it possible to further improve the rust prevention effect. Typical examples of the aqueous crosslinkable polymer emulsions mentioned above include carboxyl-modified styrene-butadiene rubber latex, aqueous emulsions of acrylic copolymers containing carboxyl or glycidyl groups, and styrene-acrylic copolymers containing carboxyl or glycidyl groups. Examples include aqueous emulsions of polymers. The heat-melting organic filler (component A) to be dispersed in the aqueous polymer emulsion as described above is
It has a melting point or softening point that is at least 10°C higher than the minimum film forming temperature of the aqueous emulsion and within a temperature range of 40 to 250°C. The melting point or softening point (hereinafter referred to as "melting point") of the heat-melting organic filler is lower than the minimum film forming temperature of the aqueous polymer emulsion, or the difference therebetween is 10°C.
If it is less than that, the melting of the heat-melting organic filler will proceed before the formation of a film of the polymer is sufficient, making it difficult to obtain a dense rust-preventing baked coating film, which is an object of the present invention. It becomes impossible to achieve the goal. 10% higher than the minimum film forming temperature of this aqueous emulsion.
Even if the temperature is higher than ℃, if the absolute value is below 40℃, it becomes extremely difficult to handle, which not only causes problems in terms of practicality, but also reduces the heat resistance of the coating film when applied to concrete reinforcing bars. This may weaken the reinforcing effect of the reinforcing bars. On the other hand, if the melting point reaches a high temperature exceeding 250°C, the physical properties of the aqueous polymer emulsion coating film may deteriorate during the baking process due to the high temperature, which is not practical. Therefore, it is necessary to use a heat-melting organic filler having a melting point as described above. As the heat-melting organic filler used in this invention, any material may be used as long as it satisfies the above requirements, but it should be one that has good compatibility with the polymer in the aqueous emulsion. It is preferable to use a rust preventive agent, and depending on the purpose of the rust preventive agent, for example, if it is for concrete reinforcing bars, use one with excellent alkali resistance, or use the most suitable one with the above-mentioned polymers having similar characteristics. It is preferable to select and use them. Examples of suitable heat-melting organic fillers are as follows. Polystyrene, acrylonitrile/styrene (0/100 to 60/40) copolymer,
Styrene/methyl methacrylate (0/100-100/
0) Copolymer, polypropylene, polyethylene,
Examples include synthetic resins such as phenolic resin initial condensates, uncured epoxy resins, rosin, petroleum resins, and bituminous materials that exhibit a glass-like solid state at room temperature.
These exemplified materials not only have good compatibility with the polymers of the aqueous emulsions already exemplified as those preferably used in this invention, but also have excellent alkali resistance, and are suitable for emulsion-based baking molds according to the present invention. It is particularly suitable for use as a rust preventive agent. Among the examples listed above, uncured cross-linked resins such as phenolic resin initial condensates (including alkylphenol resin initial condensates) and uncured epoxy resins form a tough film on their own to prevent Not only does it improve the mechanical properties and density of the rust coating, but when used in combination with the crosslinkable polymer mentioned above, it crosslinks and hardens integrally with the polymer, creating a rust-preventive coating. The denseness and adhesion to the object to be treated are greatly improved, and the best effects can be achieved. The shape and dimensions of the above-mentioned heat-melting organic filler are not particularly limited as long as it can be dispersed in the above-mentioned aqueous polymer emulsion.
Any shape and size such as powder, particulate, flake or short fibers can be used without any problem. However, if the rust preventive agent is too fine, it may cause the paint film to sag during application, which is undesirable, and it is therefore desirable to use granular or short fibrous materials. By using a product with such a shape, the coating properties of the obtained rust preventive agent are extremely good, and it can be applied to objects with complex shapes and reinforcing bars made of iron materials of various different diameters. Effects such as being able to apply the coating uniformly and without uneven thickness, and with less sagging even if the coating is thick, are achieved, and as a result, the rust-preventing ability of the rust-preventing coating film is further improved. Therefore, it is particularly preferable to use the above-mentioned granular or short fibrous filler as the heat-melting organic filler.
Specifically speaking, it is desirable that all or part of the particulate material has a particle size of 10 μm or more, especially 40 μm or more, and the upper limit of the particle size depends on the storage stability of the resulting rust preventive agent. Alternatively, it is preferable to set the thickness to about 200 μm in consideration of the smoothness of the coated surface. In addition, in the case of short fibers,
It is preferable to use fibers with a length of about 0.1 to 10 mm. In addition, in the rust preventive agent of the present invention, an inorganic filler can be used in combination with the above-mentioned heat-melting organic filler, and in that case, as the inorganic filler, granules with a particle size of about 10 to 200 μm are used as the inorganic filler. It is preferable to use a material. When such an inorganic filler is used, it is possible to improve the coating accuracy of the rust preventive agent by its own action, so it is recommended to use a powdered heat-melting organic filler at the same time. There is no problem. The blending amount of the above-mentioned heat-melting organic filler varies depending on the type of filler, but generally, based on the solid content of the polymer in the aqueous polymer emulsion, the solid content is 100 parts by weight. (hereinafter referred to as “Department”)
It is preferable to set the amount of the filler in the range of 3 to 500 parts per unit. In order to obtain a dense coating film, the amount may be set at 10 to 500 parts when no bituminous emulsion is used, and the range from 3 to 500 parts when bituminous emulsion is used as described above.
Particular preference is given in each case to a range of 20 to 100 parts. If the amount of the heat-melting organic filler is more than 500 parts, not only the density and adhesion of the coating film will not improve any further, but also the mechanical properties of the coating film may be impaired in some cases. Therefore, it is preferable to set the blending amount of the heat-melting organic filler within the range of 3 to 500 parts as described above. The general blending amount of heat-melting organic fillers is as above, but among heat-melting organic fillers, relatively coarse fillers such as granular and fibrous materials are used to improve coating properties. When using the above-mentioned relatively coarse filler as all or part of the heat-melting organic filler with the expectation that It is desirable to have a proportion of ~400 parts, preferably 40-400 parts. In this case, a heat-melting organic filler may be used alone as a relatively coarse filler to satisfy the above value. It may be used in combination with an inorganic filler so that the total amount of both is used. In some cases, the above value may be satisfied only with an inorganic filler. However, in this case as well, since it is necessary to use a heat-melting organic filler, it is necessary to use a heat-melting organic filler in the form of a powder or the like within the above-mentioned general formulation range. Furthermore, as already mentioned, the emulsion-based baking type rust preventive agent of the present invention may contain a bitumen emulsion (component <<B>>) together with the above-mentioned heat-melting organic filler (component <<A>>). In this invention, bituminous emulsion refers to one or more bituminous materials such as straight asphalt, semi-blown asphalt, natural asphalt, cutback asphalt, coal tar, oil tar, tar pitch, petroleum pitch, fatty acid bitter, etc., combined with an emulsifier. It is a common bitumen emulsion obtained by emulsifying it in an aqueous medium using stabilizers, protective colloids, etc. The bituminous material used in the bitumen emulsion may be modified by adding a polymer such as rubber. In addition, bituminous emulsions are usually classified into cationic, anionic, and nonionic types depending on the type of emulsifier, but when used in this invention, the above-mentioned polymeric aqueous emulsion, heat-melting organic filler, and It is preferable to select appropriately in consideration of the stability of mixing with inorganic fillers, antirust pigments, etc., which will be described later. The amount of the bitumen emulsion blended is set so that the solid content of the bitumen emulsion is 5 to 100 parts, particularly 7 to 30 parts, based on 100 parts of the solid content of the polymer in the aqueous polymer emulsion. It is preferable that
If the amount is less than 5 parts, no significant improvement will be observed in the adhesion between the coating film and the concrete of the building frame, between the coating film and the reinforcing bars, or in the water resistance, and therefore no significant improvement can be expected in terms of rust prevention. On the other hand, if the amount is more than 100 parts, not only the adhesion and water resistance of the coating film will not be improved as described above, but also the mechanical properties of the coating film may be easily impaired, which is not preferable. In addition, the emulsion-based baking type rust preventive agent of the present invention contains the above-mentioned heat-melting organic filler (<<A>> component).
In addition to the above-mentioned bitumen emulsion (component <<B>>), inorganic fillers, synthetic pigments, etc. may be appropriately blended as necessary. Typical examples of the above-mentioned inorganic fillers include kansuishi,
Examples include powdery or granular materials made of silica sand, talc, clay, anhydrous calcium carbonate, etc., and further examples include asbestos. This inorganic filler not only improves the coating properties of the rust preventive agent, but also reinforces the rust preventive paint film to prevent cracking over time, and also improves the adhesion between the rust preventive paint film and the concrete structure. Various desirable effects can be realized. The amount of the inorganic filler to be blended is 40 to 500 parts, preferably 80 to 500 parts, per 100 parts of polymer solid content, based on the polymer aqueous emulsion when bituminous emulsion is not added. It is desirable to set the number to 400 copies. Furthermore, when blending a bituminous emulsion, the amount of inorganic filler blended can be increased compared to the above, and the amount of inorganic filler per 100 parts of polymer solid content is 40 to 40 parts per 100 parts of polymer solid content. 800 copies, preferably 80-500
It can be set to become a section. In addition, when using the rust preventive for the purpose of improving the coating properties, granules or short fibrous materials with a particle size of about 10 to 200 μm, especially granules, in the same shape as the heat-melting organic filler may be used. It is desirable that the total amount is 10 to 400 parts, particularly 40 to 400 parts, per 100 parts of the solid content of the polymer. When blending an inorganic filler, the total amount of the coarse particulate matter with the coarse heat-melting organic filler as described above is 10 parts per 100 parts of polymer solid content.
The remainder may be in the form of fine particles or powder, as long as it falls within the range of 400 parts to 400 parts, preferably 40 to 400 parts. Rather, in order to comprehensively exhibit the effect of the inorganic filler blend, it is desirable that coarse particles occupy the above proportion in the total blend of the inorganic filler, and the remainder be in the form of fine particles or powder. For example, it is most preferable to use a mixture of silica sand with a particle size of 40 to 150 μm and one or more of talc powder, clay powder, anhydrous calcium carbonate powder, and silica powder at a ratio of about 1:0.1 to 1:5 (weight ratio). It is. Further, as the anti-corrosive pigment, any pigment that is blended in ordinary anti-corrosive paints can be used. Typical examples include zinc phosphate, aluminum phosphate, lead phosphate, zinc molybdate, barium metaborate, calcium hydroxide, and the like. These antirust pigments can be used alone or in combination to improve the antirust effect of the antirust agent. The amount of the above anti-rust pigment is:
It is desirable to set the amount of the pigment in an amount of 10 to 200 parts per 100 parts of the solid content of the polymer in the aqueous polymer emulsion. In other words, the blending amount is 10
If the amount is less than 200 parts, a sufficient enhancement effect cannot be expected, and even if it exceeds 200 parts, not only will no further enhancement in rust preventive power be obtained, but the storage stability of the rust preventive agent itself will deteriorate. This is because such disadvantages arise. In addition to the above-mentioned raw materials, the emulsion-based baking type rust preventive agent of the present invention further contains, if necessary,
Other additives such as pigment dispersants, antifoaming agents, thickeners, and colorants are appropriately selected and blended. in this case,
The above additives are selected based on the object to which the rust preventive agent is applied. Further, the emulsion-based baking type rust preventive agent of the present invention is produced using the above-mentioned raw materials and according to a conventional method for producing emulsion-based paints. Rust prevention treatment using the emulsion-based baking type rust preventive agent of the present invention is normally carried out as follows.
First, the above-mentioned emulsion-based baking type rust preventive agent is applied to the object to be treated, such as concrete reinforcing bars, using an appropriate method such as roller coating or dipping, and then pre-drying is performed to form an aqueous polymeric emulsion. A polymer film (emulsion film) containing an organic filler, or an organic filler and a bituminous emulsion, or in some cases an inorganic filler, an anticorrosion pigment, etc. Let it form on top. The above pre-drying process forms a polymer aqueous emulsion into a film, but is generally carried out under temperature conditions that do not melt or soften the heat-melting organic filler.
It is carried out at a temperature of ~100℃. As already mentioned, if the above-mentioned pre-drying is performed at a temperature at which the heat-melting organic filler melts or softens, the heat-melting organic filler will melt and fluidize before or during the formation of the emulsion coating film. Therefore, sufficient void filling is not performed, and the rust preventive effect unique to the rust preventive agent of the present invention cannot be obtained. In addition, even if the temperature range is such that the heat-melting organic filler does not melt or soften, if the pre-drying temperature is set to a high temperature of 100°C or higher, blistering and rough pores will occur in the emulsion coating film that is formed, making it uniform and dense. It becomes difficult to form a rust-proof coating film. Therefore, the pre-drying conditions are appropriately set taking these into consideration. After an emulsion coating film is formed by preliminary drying in this manner, baking is performed to form the emulsion coating film into a dense rust-preventing baked coating film. The above-mentioned baking is performed by heat treatment at a temperature that melts or softens the thermofusible organic filler, generally in the range of 100 to 200°C, for 5 to 30 minutes or longer. .
As a result, the heat-melting organic filler melts and fluidizes, filling pinholes and voids in the emulsion coating, and this effect, combined with the so-called baking effect, makes the emulsion coating extremely dense and rust-proof. It becomes a baked coating. At this time, the heat-melting organic filler is also present between the anti-rust baking coating and the object to be treated or the concrete skeleton, contributing to improving the adhesion between the two. In addition, when bituminous emulsion is present, the adhesion described above is further improved, and the adhesion between the rust-proof reinforcing bars and the concrete of the building structure during on-site construction is also better, and water resistance is also improved, resulting in excellent rust prevention. The effect is demonstrated. In addition, when using a crosslinking hardening material for one or both of the polymeric material and the heat-melting organic filler in the aqueous emulsion, various conditions must be set so that the crosslinking hardening reaction is completed during the baking process. What is done is done. In addition, when using the rust preventive agent of the present invention for rust prevention of reinforcing bars for ALC plates, autoclave treatment (usually at 180°C, 10 atm,
Since the 10 hour condition) can be used directly as an alternative to the above-mentioned baking, there is no need to go through the baking process again, making it possible to shorten the manufacturing process. [Effects of the Invention] As described above, the emulsion-based baking type rust preventive agent of the present invention has the following properties unique to the aqueous emulsion-based rust preventive agent:
This paint has advantages such as good workability, storage stability (pot life) and economic efficiency, and also exhibits a dense baked coating comparable to solvent-based rust preventives and excellent adhesion to objects to be treated such as reinforcing bars. This is an extremely useful product in fields where prevention of rusting of concrete reinforcing bars is strongly desired. Next, examples of the present invention will be described together with comparative examples. [Examples 1 to 12, Comparative Examples 1 to 3] Bisphenol A type epoxy resin (R-304, manufactured by Mitsui Petrochemical Epoxy Co., Ltd.) with a melting point of 100°C was crushed and classified with a sieve, and then fine particle size was obtained. For particles, further air separation is performed to obtain particles with particle sizes of 10 μm or less, 10-43 μm, 43-104 μm, and 104-
Heat-fusible organic fillers having four types of particle sizes within the range of 140 μm were obtained. Next, the granular heat-fusible organic filler and, in some cases, silica sand with a particle size of 43 to 140 μm as an inorganic filler are mixed with carboxylated styrene-butadiene rubber latex (JSR0596,
Comparative Example 1 was prepared by blending a product manufactured by Japan Synthetic Rubber Co., Ltd. with a solid content of 50% (weight, same hereinafter) (minimum film forming temperature 0°C) in the proportions shown in Table 1 below. Comparative Example 2 contains no filler at all, Comparative Example 3 contains only an inorganic filler, and Comparative Example 3 contains Portland cement. The thus obtained rust preventive agent was examined for its paintability and rust preventive performance on the object to be treated using the methods described below, and the results are also shown in Table 1. Paintability: Add water to each rust preventive to reduce the viscosity to approximately 800 cps
(20℃), and 2mm diameter reinforcing bars and 12mm diameter reinforcing bars were dip coated. This is 60
Pre-dry at 185°C for 5 minutes, then dry at 185°C for 10 minutes.
After baking for a minute, the coating thickness of each part was measured and the appearance was inspected to check the uniformity of the coating. Rust prevention: Reinforcing bars that have been rust-proofed in the same manner as above are placed in a 5% sodium chloride aqueous solution at 50°C for 70 minutes.
After being immersed for a day, the state of rusting was observed.

【table】

[Examples 13 and 14, Comparative Example 4]

Paraffin wax (wax) with a softening point of 47°C, paraffin wax (wax) with a softening point of 70°C, and microcrystalline wax (wax) with a softening point of 84°C were prepared. A wax-based organic filler was obtained by treating these waxes in the following manner. That is, 1 part of a nonionic emulsifier was added to 100 parts of the above wax, melted and mixed at 105°C, and the product was dropped into 300 parts of hot water (90 to 95°C) under high speed stirring to disperse the wax into fine particles. I let it happen. After cooling, the particulate wax is filtered,
After washing with cold water, classify with a sieve to obtain a particle size of 74~
A 140 μm wax-based filler was used. The three types of wax-based fillers, inorganic fillers, and anti-corrosion pigments thus obtained were mixed into an aqueous acrylic copolymer emulsion (Yodozol MM62, manufactured by Kanebo NSC, solid content 50%, minimum film forming temperature). 50
℃) in the proportions shown in Table 2 to prepare a rust preventive agent. The heat-melting organic filler used in Comparative Example 4 has a softening point of 47°C, which is lower than the minimum film-forming temperature of the aqueous emulsion, which is 50°C. does not meet the requirements for organic fillers used in The paintability and antirust performance of the rust preventive agent thus obtained were examined using the methods described below, and the results are also shown in Table 2. Paintability: Add water to rust preventive agent to reduce viscosity to approximately 800 cps
(20°C), and 2mm and 12mm diameter reinforcing bars and L-beam steel were dip coated. Pre-dry this at 65℃ for 10 minutes, and then
After baking at 120°C for 10 minutes, the uniformity of the coating film was checked in the same manner as in Example 1. Rust prevention: The above test piece was tested according to JIS K5400 salt spray test, and after 240 hours rust,
The occurrence of blisters was observed.

[Examples 15 and 16, Comparative Example 5]

Styrene prepared by dissolving 5 parts of polyvinyl alcohol with a degree of polymerization of 1700 and a degree of saponification of 88 mol% in 250 parts of water, and 1 part of benzoyl peroxide dissolved in this.
Add 100 parts, heat with stirring, and bring to 80℃ for 55 minutes.
Holds time. After cooling, the reactant was taken out, thoroughly washed with water and dried, and then classified using a sieve to obtain polystyrene resin particles having a particle size of 45 to 104 μm. The melting point of this product was 180°C.
Next, this polystyrene resin granule was used as an organic filler, and together with the raw materials shown in Table 3, an aqueous emulsion of styrene-acrylic acid ester copolymer (Yodozol GF 1, manufactured by Kanebo NSC, solid content 50%) was prepared. , a minimum film forming temperature of 0°C) were blended and mixed in the proportions shown in Table 3 to prepare a rust preventive agent. The thus obtained rust preventive agent was tested for paintability and rust preventive performance according to the methods described below, and the results are also shown in Table 3. Paintability: Add water to rust preventive agent to reduce viscosity to approximately 800 cps
(20℃) was applied with a brush to 2mm diameter and 9mm diameter reinforcing bars and L-shaped steel, and then heated to 80℃ for 10 minutes.
After pre-drying for a minute, it was baked at 200°C for 10 minutes.
The uniformity of the coating film on the sample obtained here was checked in the same manner as in Example 1. Rust prevention: Similar to Example 13, it was conducted according to the JIS K5400 salt spray test.

[Examples 17 and 18, Comparative Examples 6 and 7]

0.2 parts of sodium dodecylbenzenesulfonate and 1 part of polyoxyethylene nonyl phenyl ether were dissolved in 130 parts of water, and the temperature was raised to 80°C with stirring. Next, a mixture of 95 parts of styrene and 5 parts of methacrylic acid and a mixture of 0.1 part of ammonium persulfate and 20 parts of water were each added dropwise over 2 hours, and heated to 80°C for 2 hours.
It kept time. After cooling this, aqueous ammonia was added to adjust the pH to 9. the result,
A dispersion liquid (solid content 40%, viscosity 200 cps (at 20°C)) containing fine particulate styrene-methacrylic acid copolymer (carboxyl group-containing resin) with an average particle diameter of 0.4 μm was obtained. Next, the dispersion of carboxyl group-containing resin (organic filler) obtained as described above was added to an aqueous emulsion (acrylic copolymer) of carboxyl group-containing acrylic copolymer along with other raw materials shown in Table 4. Polymer emulsion A) [Yodozol 32A812, manufactured by Kanebo NSC, solid content
50%, minimum film forming temperature 15℃] or acrylic copolymer emulsion containing no carboxyl group (acrylic copolymer B) [Yodozol D22, manufactured by Kanebo NSC, solid content 50%, minimum film forming temperature 26 ℃] in the proportions shown in Table 4 to prepare a rust preventive agent. In Comparative Examples 6 and 7, the above organic filler dispersion was not used. The paintability and rust prevention performance of the rust preventive agent obtained in this way were investigated using the methods described below.
The results are also shown in Table 4. Paintability: Add water to rust preventive agent to reduce viscosity to approximately 800 cps
(20℃), 2mm diameter and 9mm diameter.
Dip-coat mm-diameter reinforcing bars and L-shaped steel at 80°C.
After pre-drying at 190℃ for 10 minutes, it was baked at 190℃ for 30 minutes. Example 1 for the sample obtained here
The uniformity of the coating film was checked in the same manner as above. Rust prevention: Similar to Example 13, it was conducted according to the JIS K5400 salt spray test.

[Example 19, Comparative Example 8]

Instead of acrylic copolymer emulsion A,
Styrene-butadiene rubber latex (JSR0591,
Manufactured by Japan Synthetic Rubber Co., Ltd., solid content 50%, minimum film forming temperature 0
A rust preventive agent (Example 19, Comparative Example 8) was obtained in the same manner as in Example 17 and Comparative Example 6, except that the anti-corrosion agent (Example 19, Comparative Example 8) was used. The paintability and rust prevention properties of the thus obtained rust preventives of Example 19 and Comparative Example 8 were examined in the same manner as in Example 17 and Comparative Example 6, and both showed good paintability. Although there was no major difference, the rust prevention performance of Example 19 was 240.
Although no rust was observed even after the passage of time, in Comparative Example 6, the coating film partially blistered and rust spots were observed. [Example 20] Uncured phenolic resin beads (Bell Pearl S830, manufactured by Kanebo Co., Ltd.) with an average particle size of 20 μm were used as an organic filler, and they were mixed with methylol group-containing vinyl acetate acrylic beads together with other raw materials shown in Table 5. Prepare a rust inhibitor by mixing aqueous polymer emulsion (125-2833, manufactured by National Starch and Chemical Co., Ltd., solid content 50%, minimum film forming temperature 0°C) in the proportions shown in the table. did. The resulting rust preventive was tested for paintability (viscosity was approximately
600 cps, and the baking time was set at 180°C for 20 minutes), and the rust prevention properties were investigated. The results are also shown in Table 5.

【table】

[Table] Manufactured by Kogyo Co., Ltd. [Example 21] _C9 petroleum resin with a softening point of 90°C (Alcon P-90,
Arakawa Chemical Industries Co., Ltd.) was crushed and classified with a sieve to collect granules with a particle size of 43 to 104 μm, which was used as an organic filler to produce styrene-acrylic ester along with other raw materials shown in Table 6. A rust preventive agent was obtained by blending the copolymer into an aqueous emulsion (Yodozol GF-1) in the proportions shown in Table 6. The paintability and antirust performance of the obtained rust preventive agent were examined using the methods described below, and the results are also shown in Table 6. Paintability: Add water to rust preventive agent to reduce viscosity to approximately 800 cps
(20℃)
Roller coating was applied to the molded steel. After pre-drying this at 50°C for 10 minutes and baking it at 130°C for 30 minutes, the uniformity of the coating film was checked in the same manner as in Example 1. Rust prevention: Similar to Example 13, it was conducted based on the JIS K5400 salt spray test.

【table】

[Examples 22 to 28, Comparative Example 9]

Styrene prepared by dissolving 5 parts of polyvinyl alcohol with a degree of polymerization of 1700 and a degree of saponification of 88 mol% in 250 parts of water, and 1 part of benzoyl peroxide dissolved therein.
Add 100 parts, heat with stirring, and bring to 80℃ for 5 minutes.
Holds time. After cooling, the reactant was taken out, thoroughly washed with water and dried, and then classified using a sieve to obtain polystyrene resin particles having a particle size of 43 to 74 μm. The melting point of this product was 180°C.
Next, this polystyrene resin granule was used as an organic filler, and an aqueous emulsion of an acrylic copolymer (Yodozol AD82 , manufactured by Kanebo NSC, solid content 45%, minimum film forming temperature 0°C)
were mixed in the proportions shown in Table 7 to prepare rust preventives (Examples 22 to 27).For comparison, a rust preventive containing no asphalt emulsion (Example 28) and an organic filler were also prepared. A conventional rust preventive agent (Comparative Example 9) containing no asphalt emulsion was also prepared at the same time.The rust preventive agent thus obtained was tested for paintability, rust preventive agent, and cement mortar according to the method described below. The results are shown in Table 7. Paintability: Add water to each rust preventive to reduce the viscosity to approximately 800 cps.
(20°C), 2 mm diameter reinforcing bars, 12 mm diameter reinforcing bars, and L-shaped steel were dip coated. Pre-dry this at 70℃ for 10 minutes, and then
After baking at 200°C for 20 minutes, the uniformity of the coating was checked by measuring the thickness of each part and inspecting the appearance. Rust prevention: The test pieces prepared in the above paintability test were tested according to the JIS K5400 salt spray test, and the occurrence of rust and blisters was observed after 240 hours. Cement mortar adhesion: The test piece prepared in the above paintability test was placed vertically in a standard sand mortar obtained by kneading 100 parts of Portland cement, 200 parts of Toyoura standard sand, and 65 parts of water, and the test piece was placed vertically at 20°C.
After curing in a humid air for 28 days, the mortar was destroyed and the state of adhesion of the mortar to the test piece was observed.

【table】

[Table] As is clear from the results in Table 7, the rust inhibitor of Example 28, which does not contain an asphalt emulsifier, has a higher Although it exhibits excellent properties as a rust preventive agent in terms of paintability, rust prevention, and cement mortar adhesion, there is still room for improvement in cement mortar adhesion. In the case of rust inhibitors (Examples 22 to 27), cement mortar adhesion is also good. In addition, the effect of improving adhesion by blending this asphalt emulsifier is that the blending amount of the asphalt emulsifier is
This is particularly noticeable when the solid content is within the range of 5 to 100 parts. Note that when the rust preventive agent of Example 28 was used for rust prevention of reinforcing bars for ALC, it exhibited adhesion between the coating film and the concrete frame that was sufficiently satisfactory for practical use. [Examples 29 to 33] A bisphenol A type epoxy resin (R-304, manufactured by Mitsui Petrochemical Epoxy Co., Ltd.) with a melting point of 100°C was crushed, classified with a sieve, and a portion with a particle size of 43 to 104 μm was collected. This was used as a hot melt organic filler. Separately, 80 parts of coal tar (JIS K2439 refined tar No. 1) and coal tar pitch (JIS K2439 refined tar No. 1)
20 parts of general purpose pitcher) were heated and melted at 60°C, and then 3 parts of polyoxyethylene nonyl phenyl ether and 0.5 part of polypynyl alcohol were dissolved.
A coal tar emulsion (solid content 60%) was prepared by adding it to warm water at 60°C and stirring. The above organic filler and coal tar emulsion were combined with other raw materials in an aqueous emulsion of carboxylated styrene-acrylic acid ester copolymer (Iodosol GF-1, manufactured by Kanebo NSC, solid content 50%, minimum film formation). temperature 0℃)
and were mixed in the proportions shown in Table 8 to prepare rust preventive agents (Examples 29 and 30). For comparison, rust preventives containing no coal tar emulsion were also prepared at the same time (Examples 31 and 32). The thus obtained rust preventive was tested for paintability, rust preventive and cement mortar adhesion in the same manner as in Examples 22 to 27, and the results are also shown in Table 8.

[Table] From the results in Table 8, in the case of a rust preventive agent containing bituminous emulsion (coal tar emulsion), even if the amount of inorganic filler added is increased, the physical properties of the coating film decrease, and therefore the rust prevention property decreases. It can be seen that this method is advantageous in terms of economy as well.

Claims (1)

[Claims] 1 Acrylic copolymer, styrene-acrylic copolymer, synthetic rubber latex, natural rubber latex, ethylene-vinyl acetate copolymer, vinyl acetate-versatonic acid vinyl ester copolymer, and vinyl chloride-chloride Add the following to a polymer aqueous emulsion whose main component is at least one polymer selected from the group consisting of vinylidene copolymers.
An emulsion-based baking type rust preventive agent containing at least component (A) of component (A) and component (B). (A) Polystyrene, polyacrylonitrile, acrylonitrile-styrene copolymer, polymethyl methacrylate, styrene-methyl methacrylate copolymer, polypropylene, polyethylene, phenolic resin initial condensate, uncured epoxy resin, rosin, petroleum resin, and room temperature at least one compound selected from the group consisting of solid bituminous substances, at a temperature at least 10°C higher than the minimum film forming temperature of the above emulsion and from 40 to 40°C;
A heat-melting organic filler made of a compound having a melting point or softening point within a temperature range of 250°C. (B) Bituminous emulsion. 2. The emulsion-based baking-type rust preventive agent according to claim 1, wherein the aqueous polymeric emulsion having coating film-forming ability has a minimum film-forming temperature of 50°C or less. 3. A patent claim in which the heat-melting organic filler has a melting point or softening point at least 50°C higher than the minimum film-forming temperature of the aqueous polymer emulsion and within a temperature range of 40 to 250°C. The emulsion-based baking type rust preventive agent according to item 1 or 2. 4 The blending amount of the heat-melting organic filler is 100% of the solid content of the polymer in the polymer aqueous emulsion.
3 to 500 parts by weight of thermofusible organic filler
The emulsion-based baking type rust preventive agent according to any one of claims 1 to 3, wherein the proportion is set to be in parts by weight. 5 At least a portion of the heat-melting organic filler is
Granules with a particle size of 10 to 200 μm or fiber length of 0.1 to 10
mm short fibrous material, and is blended in a total amount of 10 to 400 parts by weight based on 100 parts by weight of the solid content of the polymer in the aqueous polymer emulsion. The emulsion-based baking type rust preventive agent according to any one of Item 4. 6. Claim 1, wherein the heat-melting organic filler has a group capable of crosslinking in its molecule.
The emulsion-based baking type rust preventive agent according to any one of items 1 to 5. 7. The emulsion-based baking type rust preventive agent according to claim 6, wherein the group capable of crosslinking reaction is a carboxyl group, a glycidyl group, or a methylol group. 8. A patent in which the heat-melting organic filler having a crosslinkable group in its molecule is at least one compound selected from the group consisting of an uncured epoxy resin, a phenolic resin initial condensate, and an alkylphenol resin initial condensate. The emulsion-based baking type rust preventive agent according to claim 6 or 7. 9. High-molecular substance The emulsion-based baking-type rust preventive agent according to claim 6, wherein the high-molecular substance of the aqueous emulsion has a group capable of crosslinking reaction in its molecule. 10. The emulsion-based baking type rust preventive agent according to claim 9, wherein the group capable of crosslinking reaction is a carboxyl group, a glycidyl group, or a methylol group. 11 Polymer The polymer of the aqueous emulsion is
Selected from the group consisting of carboxylated styrene-butadiene rubber, alkyl group-containing acrylic copolymer, carboxyl group-containing styrene-acrylic copolymer, glycidyl group-containing acrylic copolymer, and glycidyl group-containing styrene-acrylic copolymer The emulsion-based baking type rust preventive agent according to claim 9 or 10, which is at least one compound comprising: 12. The emulsion-based baking type rust preventive according to any one of claims 1 to 11, wherein the bitumen emulsion is at least one bitumen emulsion selected from the group consisting of an asphalt emulsion, a tar emulsion, and a tarpitch emulsion. agent. 13. Claim 1, wherein the amount of bituminous emulsion blended is set at a ratio of 5 to 100 parts by weight based on 100 parts by weight of the solid content of the polymer in the aqueous emulsion of the polymer. or 12th
The emulsion-based baking type rust preventive agent according to any one of the above. 14. The emulsion-based baking type rust preventive agent according to any one of claims 1 to 13, which contains an inorganic filler. 15 A patent claim in which the blending amount of the inorganic filler is set at a ratio of 40 to 800 parts by weight based on 100 parts by weight of the solid content of the polymer in the aqueous polymer emulsion. Range 1
The emulsion-based baking type rust preventive agent described in item 4. 16 At least a portion of the inorganic filler has a particle size of 10
It is a granular material of ~200μ or a short fibrous material with a fiber length of 0.1 to 10 mm, and the total amount is 10 to 100 parts by weight per 100 parts by weight of the solid content of the polymer in the polymer aqueous emulsion.
The emulsion-based baking type rust preventive agent according to claim 14 or 15, which is blended in a proportion of 400 parts by weight. 17. The emulsion-based baking type rust preventive agent according to any one of claims 1 to 16, which contains a rust preventive pigment. 18 A patent claim in which the amount of the rust preventive pigment is set to be 10 to 200 parts by weight per 100 parts by weight of the solid content of the polymer in the aqueous polymer emulsion. The emulsion-based baking type rust preventive agent according to item 17.