JP3278004B2 - Fluororesin aqueous dispersion for building exterior material, method for producing the same, and application thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention provides a new and useful
The present invention relates to an aqueous dispersion of a fluororesin for a building exterior material, a method for producing the same, and an application thereof. More specifically, the present invention relates to a fluororesin aqueous dispersion for building exterior materials obtained by using a fluorine atom-containing monomer consisting of only chlorotrifluoroethylene as an essential component, a method for producing the same, and an application thereof. , As the minimum essential monomer component,
The present invention relates to an aqueous dispersion of a core-shell type fluororesin for a building exterior material, which comprises a fluorine atom-containing monomer consisting of chlorotrifluoroethylene alone, and which can be suitably used particularly for coating, and a method for producing the same and its application.

[0002]

2. Description of the Related Art In the field of exterior coating materials, in recent years,
There is a great demand for a coating material that is extremely practical and has no deterioration or discoloration over a long period of time. Particularly, in the field of civil engineering and construction, coating of the surface of a so-called alkaline inorganic cured material such as a concrete frame, a wall material or a roof material is carried out. , Water resistance and weather resistance.

Among these coating materials, aqueous organic polymer materials such as acrylic copolymers and acrylic-styrene copolymers are widely used because of their simple coating treatment.

[0004] However, especially when used as building exterior materials, those having a life of at least 10 years or more, and moreover, semi-permanent ones are being demanded, and acrylic copolymers and acrylic-styrene are required. When an aqueous polymer such as a system copolymer is used for the top coat, it is difficult to say that the weather resistance is sufficient, and as a result, recoating is required within a short period of time.

[0005] On the other hand, fluoroolefin copolymers are known as binders that provide high weather resistance and high chemical resistance, and organic solvent solutions are already commercially available.

However, since commercially available binders contain organic solvents, they have problems in terms of fire danger, harmfulness, air pollution, and the like, and aqueous binders are required.

On the other hand, tetrafluoroethylene,
Although the use of aqueous dispersions of polymers (fluoroolefin polymers) such as vinylidene fluoride or hexafluoropropylene has been proposed, all of these polymers require baking at high temperatures. That is.

Incidentally, Japanese Patent Application Laid-Open No. 57-38845 discloses a copolymer of vinylidene fluoride and hexafluoropropylene, and the copolymer has an intrinsic viscosity [η] of 0. Despite having a low molecular weight of 0.1 to 0.5, baking at a high temperature of 180 to 230 ° C is still required.

Therefore, even in the case of architectural paints which need to form a coating film at room temperature or factory paints which rely on forced drying, the above-mentioned high-temperature baking is not practically practical. It is possible and not suitable for such applications.

[0010] Moreover, the fluoroolefin-based monomers are expensive, so that the copolymer is
It is disadvantageous from an economical point of being composed only of the fluoroolefin-based monomers.

Japanese Patent Application Laid-Open No. 61-26167 discloses a method for solving various problems as described above, which comprises a fluoroolefin, an alkyl vinyl ether, and a carboxylic acid vinyl ester.
An emulsion copolymer-based coating resin composition has been disclosed, and as an exterior coating material, it can be said that it is suitable for the time being. It is insufficient in terms of dispersibility and stain resistance.

As described above, as far as the prior art is concerned, a water-based coating composition containing a highly durable fluoroolefin unit as a main component uses a relatively large amount of expensive fluoroolefin-based monomers. The fact is that it is not sufficient in terms of adhesion to the substrate, dispersibility of the pigment, and stain resistance. It is.

[0013]

SUMMARY OF THE INVENTION However, the present inventors have proposed an expensive fluoroolefin-based monomer without impairing the performance of any of the fluoroolefin-based aqueous coating compositions known in the prior art. With the greatest aim of expanding the field of application of the composition by reducing the amount of the compounds used and improving various properties such as adhesion to the base material and dispersibility of the pigment, Started.

Accordingly, an object of the present invention is to provide, in part, an expensive fluoroolefin-based monomer without impairing the performance of the fluoroolefin-based aqueous coating composition of this kind. The purpose of the present invention is to expand the field of application of the composition by reducing the amount of the composition used and improving various properties such as adhesion to a substrate and dispersibility of a pigment.

[0015]

Means for Solving the Problems In view of the present situation, the present inventors have conducted intensive studies with the aim of solving the problems to be solved by the invention as described above. By localizing, the amount of the fluoroolefin-based monomer used can be reduced for the first time, and in addition, when the obtained emulsion is used for water-based paint, its durability can be reduced. Without impairing the ability to improve various properties such as adhesion to the substrate and pigment dispersibility,
Upon finding out, the present invention has been completed.

That is, in preparing a fluoroolefin-based emulsion, a so-called core-shell polymerization method in which a fluoroolefin unit derived from a fluoroolefin-based monomer is localized relatively only inside the emulsion particles. For the first time, we find what we can achieve by applying
The present invention has been completed.

That is, according to the present invention, basically, the interior of the particle is occupied by a resin derived from a fluorine atom-containing monomer consisting of only chlorotrifluoroethylene, while the outer shell of the particle is made of fluorine. An object of the present invention is to provide an aqueous dispersion (fluoroolefin copolymer emulsion) of a core-shell type fluororesin for a building exterior material, which is occupied by a resin derived from atoms-free monomers. ,
Or,

In preparing an aqueous resin dispersion by radical emulsion polymerization in an aqueous medium in the presence of an emulsifier, a fluorine atom-containing monomer consisting of only chlorotrifluoroethylene is required as a first step. Polymerizing the monomer mixture as the component (a) to obtain an aqueous dispersion of a fluorine-containing resin; as a second step, in the presence of the aqueous dispersion of the fluororesin, a fluorine-free monomer A core-shell type fluororesin aqueous dispersion for building exterior materials, in which the interior of particles is occupied by a resin derived from monomers containing no fluorine atom, comprising polymerizing a monomer mixture containing as an essential component To provide a method for producing a polymer (fluoroolefin-based copolymer emulsion),

At the same time, while the interior of the particle is occupied by a resin derived from a fluorine atom-containing monomer consisting only of chlorotrifluoroethylene, the particle outer shell has a fluorine atom-free monomer. For a building exterior material comprising such a core-shell type fluororesin aqueous dispersion (fluoroolefin copolymer emulsion) for a specific building exterior material as occupied by a resin derived from It is intended to provide a paint, and also an application of the paint for a building exterior material.

The core-shell polymerization method referred to in the present invention is:
In a method of subjecting a monomer mixture to radical emulsion polymerization in an aqueous medium in the presence of an emulsifier, a particle mixture obtained by subjecting a monomer mixture having a different composition to at least two stages of a stepwise polymerization step. It can be defined as a polymerization method in which emulsion particles having different compositions are obtained along the radial direction.

Specifically, for example, when two types of monomer mixtures, monomer mixture A and monomer mixture B, are used, first, monomer mixture A is polymerized, and then, By polymerizing the monomer mixture B, the polymer A obtained from the monomer mixture A is present inside the particles (core portion), and the monomer mixture B is present outside the particles (shell portion). Emulsion particles in the form of the presence of polymer B obtained from B are obtained.

In this case, the polymerization of the monomer mixture A may be performed, and then the polymerization of the monomer mixture B may be continued in the same reaction vessel. After the completion of the polymerization of the monomer mixture A, the product may be taken out once, and thereafter, the polymerization of the monomer mixture B may be carried out.
In addition to the reaction of only two steps, polymerization of other types of monomers may be repeated to give a multi-layer structure, that is, a so-called multilayer structure.

In the present invention, such a monomer mixture A is a monomer mixture containing a fluorine atom-containing monomer (fluoroolefin monomer) consisting of only chlorotrifluoroethylene as an essential component. A monomer mixture is used. As one monomer mixture B, a monomer mixture containing no fluorine atom, that is, a monomer mixture containing a monomer having no fluorine atom as an essential component Is used.

[0024]

[0025]

As the monomers other than the fluorine atom-containing monomers constituting the monomer mixture A, various monomers such as those used as the monomer mixture B exemplified below are used. You can do it.

These monomers are appropriately selected in consideration of the glass transition point, the minimum film forming temperature, and the like of the finally obtained copolymer. Preferably, in addition to fluoroolefin monomers, carboxylic acid vinyl ester monomers, olefins, carboxyl group-containing monomers and / or monomers copolymerizable therewith. Combinations of crosslinkable monomers are suitable.

Next, used as a monomer mixture B,
Examples of the above-mentioned monomers having no fluorine atom include the following. That is, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl 2-ethylhexanoate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl salicylate, vinyl monochloroacetate, Including vinyl cyclohexanecarboxylate or vinyl p-tert-butylbenzoate,

Further, there are various vinyl ester monomers of carboxylic acid such as "Veova" (vinyl ester manufactured by Shell Co., Netherlands), and among these monomers, particularly preferable. Examples include vinyl pivalate, vinyl caproate, vinyl 2-ethylhexanoate, vinyl versatate (vinyl neononanoate, vinyl neodecanoate), vinyl laurate, vinyl stearate, vinyl cyclohexanecarboxylate, p-tert.
And vinyl esters of carboxylic acids having a linear, branched or cyclic alkyl structure having 5 or more carbon atoms, such as vinyl butyl benzoate or "Veoba".

As described above, the carboxylic acid moiety in the carboxylic acid vinyl ester monomer has a straight-chain, branched or cyclic alkyl structure having 5 or more carbon atoms in the acid. In order to enhance the weather resistance and the like of the film, a material having a carbon number of 6 or more is more preferable.

That is, a straight chain having 5 or more carbon atoms
Vinyl ester monomers of a carboxylic acid having a branched or cyclic alkyl structure have a bulky alkyl group in the molecular structure, so that the water repellency of the finally obtained film is improved, and high-temperature water or base This has the effect of suppressing the hydrolysis of the ester bond due to an acidic substance or the like.

Therefore, by using the monomers, it is possible to satisfy the long-term durability after forming the film. On the other hand, in the case of a carboxylic acid vinyl ester having less than 5 carbon atoms, although a film having good weather resistance can be obtained, difficulties are observed in water resistance and alkali resistance over a long period of time.

Furthermore, only typical ones used as the above-mentioned monomer mixture B are exemplified, and methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, Isoamyl-, n-hexyl-, n-octyl- or 2-ethylhexyl-
Alkyl vinyl ethers having various linear or branched alkyl groups such as vinyl ether; cyclopentyl vinyl ether, cyclohexyl vinyl ether or methyl

Various cycloalkyl vinyl ethers having a (alkyl-substituted) cyclic alkyl group, such as cyclohexyl vinyl ether; or various aralkyl vinyl ethers, such as benzyl vinyl ether or phenethyl vinyl ether;
Vinyl ethers having various substituted or unsubstituted alkyl groups, such as various hydroxyalkyl vinyl ethers such as hydroxybutyl vinyl ether;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3
-Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, polyethylene glycol Various hydroxyalkyl esters of (meth) acrylic acid, such as mono (meth) acrylate;

Or hydroxyl group-containing monomers represented by various unsaturated group-containing polyhydroxyalkyl esters, such as polyhydroxycarboxylic acid dihydroxyalkyl esters, such as maleic acid and fumaric acid. And so on,

(Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-alkoxymethylated (meth) acrylamide, diacetone acrylamide,
Various carboxylic acid amide group-containing monomers, such as N-methylol (meth) acrylamide;

P-styrenesulfonamide, N-methyl-p-styrenesulfonamide, N, N-dimethyl-p
-Various sulfonic acid amide group-containing monomers represented by styrene sulfonamide and the like; various N, N- monomers such as N, N-dimethylaminoethyl (meth) acrylate
Dialkylaminoalkyl (meth) acrylates or adducts with compounds having both an active hydrogen group and a tertiary amino group, which can react with various polycarboxylic acid anhydride group-containing monomers such as maleic anhydride And various tertiary amino group-containing monomers.

Represented by (meth) acrylonitrile,
Various cyano group-containing monomers; Condensation of various hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids, such as hydroxyalkyl (meth) acrylate, with various phosphate esters. Various monomers having a phosphate group obtained by the reaction;
Various kinds of monomers having a sulfonic acid group, such as 2-acrylamido-2-methylpropanesulfonic acid;

Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-
Alkyl (meth) acrylates having various C _{1 to} C ₈ , linear, branched or cyclic alkyl groups, such as ethylhexyl (meth) acrylate and cyclohexyl (meth) acrylate; or styrene, α-methylstyrene, p-tert-butyl-
Styrene, various kinds of aromatic vinyl compounds such as p-methylstyrene, various kinds of styrene or styrene derivatives, and the like;

Various (substituted) aromatic nucleus-containing (meth) acrylates such as benzyl (meth) acrylate; various unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and various monovalent acids Diesters with alcohols; vinyl chloride, vinylidene chloride, ethylene,
Various olefins such as propylene and butene-1;
Various acid anhydride group-containing monomers such as (meth) acrylic acid or crotonic acid or maleic acid, fumaric acid, itaconic acid or citraconic acid, and also various maleic anhydride- or itaconic anhydride-containing monomers. And carboxyl group-containing monomers or dicarboxylic acids typified by various unsaturated group-containing hydroxyalkyl esters / monocarboxylic acids, such as adducts with glycols.

Of these, the use of crotonic acid or itaconic acid is desirable from the viewpoint of copolymerizability. The purpose of introducing the acid group-containing monomers is to improve the stability of the aqueous resin dispersion (polymer emulsion) and to improve the adhesion to the substrate in the final use. It is to make it hurry.

If only typical representative examples of the crosslinkable monomers are given, butadiene, hexadiene, octadiene, decadiene, tetradecadiene,
-In various molecules, such as methyl-octadiene, decatriene, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene, trivinylbenzene, diallyl phthalate Monomers having two or more polymerizable unsaturated groups, or vinyltriethoxysilane, trimethoxysilylvinylether, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyl Methyldimethoxysilane, γ-
Various hydrolyzable silyl group-containing monomers such as (meth) acryloyloxypropyltriethoxysilane and γ- (meth) acryloyloxypropylmethyldiethoxysilane.

Of these, selected from the group consisting of hexadiene, octadiene, decadiene, tetradecadiene, 2-methyl-octadiene and decatriene,
One or more mixtures and / or vinyltriethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth)
Acryloyloxypropyltriethoxysilane, γ-
The use of various hydrolyzable silyl group-containing monomers such as (meth) acryloyloxypropylmethyldiethoxysilane and tris (2-methoxyethoxy) vinylsilane also provides a stable aqueous resin dispersion. desirable.

The purpose of introducing a crosslinkable monomer is to improve so-called durability such as water resistance, alkali resistance and solvent resistance, or to use a polymer having a low glass transition point. In addition, it is for imparting toughness to a film obtained from the polymer.

These monomers are appropriately selected in consideration of the glass transition point, the minimum film forming temperature, and the like of the finally obtained copolymer. Preferably, a combination of a carboxylic acid vinyl ester monomer, an olefin, a carboxyl group-containing monomer and a crosslinkable monomer is suitable. The main components constituting the monomer mixture B according to the present invention have been described above.

Next, the above-mentioned emulsifier is used to stably disperse the above-mentioned various monomers in an aqueous medium and, in addition, to sufficiently improve various properties of the film in the final use mode. The anionic emulsifier having no fluorine atom and / or the nonionic emulsifier having no fluorine atom are preferably used. Specific examples include the following.

That is, first, as typical anionic emulsifiers (including reactive emulsifiers) having no fluorine atom, only typical ones are exemplified, and alkyl (benzene) sulfonate and alkyl sulfate salt are exemplified. ,
Polyoxyethylene alkylphenol sulfate, styrene sulfonate, vinyl sulfate and various derivatives thereof.

As used herein, the term "salt" refers to a salt derived from a hydroxide of an alkali metal or a salt derived from a so-called volatile base such as ammonia or triethylamine. Among these, it is particularly desirable to use one or two or more mixtures selected from the group consisting of (substituted) alkyl (benzene) sulfonic acid salts and vinylsulfonic acid salts.

Next, as nonionic emulsifiers having no fluorine atom (including reactive emulsifiers), only typical ones are exemplified, and polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ether, Oxyethylene higher fatty acid esters, ethylene oxide-propylene oxide block copolymers and various derivatives thereof,
These may be used alone or in combination of two or more.
Of course.

Among these, the use of polyoxyethylene (substituted) alkyl (phenyl) ether is desirable also from the viewpoint of the physical properties of the finally obtained film.
The amount of use of these various emulsifiers is appropriately in the range of 0.5 to 10% based on the total weight of the monomers, including the anionic emulsifier and the nonionic emulsifier. .

Further, in combination with these emulsifiers,
Water-soluble oligomers composed of polycarboxylic acid or sulfonic acid salt, various water-soluble polymer substances such as polyvinyl alcohol or hydroxyethyl cellulose,
It can be used as a so-called protective colloid.

Here, “having no fluorine atom”
The meaning is as follows. Usually, the polymerization of fluoroolefin monomers in an aqueous medium is carried out using a fluorine atom-containing emulsifier, but in conventional systems, such a fluorine atom-containing emulsifier is inevitably used. Therefore, the surface of the particles has a relatively low energy. Therefore, when an aqueous resin dispersion (polymer emulsion) obtained according to the prior art is applied to a substrate, there is a disadvantage that the adhesion to the substrate is inevitably poor.

In the present invention, in order to overcome such drawbacks, polymerization in an emulsifier system having no fluorine atom is appropriate and preferred. However, the use of a fluorine atom-containing emulsifier, such as a perfluorooctanoate, is never prevented.

The core-shell type polymer emulsion of the present invention or the core-shell type polymer emulsion obtained according to the method of the present invention can be prepared by mixing various monomers as described above in the presence of the emulsifier. It is obtained by polymerizing in an aqueous medium.

The polymerization initiator used at that time includes:
In the emulsion polymerization, there is no particular limitation as long as it is generally used.

Specific examples include various water-soluble inorganic peroxides such as hydrogen peroxide; various persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate;
Various organic peroxides such as cumene hydroperoxide, benzoyl peroxide and t-butyl hydroperoxide; various azo-based initiators such as azobisisobutyronitrile and azobiscyanovaleric acid. However, these may be used alone or in combination of two or more.

The amount of the polymerization initiator used is suitably in the range of 0.1 to 2% by weight based on the total amount of monomers. It is needless to say that a so-called redox polymerization method in which these polymerization initiators are used in combination with a metal ion and a reducing agent may be used.

Specific examples of such a reducing agent include sodium bisulfite, sodium metabisulfite, sodium bithiosulfate, sodium hydrosulfate, sodium formaldehyde sulfoxylate, reducing sugar, and the like. Particularly representative examples are copper sulfate, ferric chloride, ferric sulfate and silver nitrate. Further, various chain transfer agents can be used.

In the present invention, first, in the coexistence of an aqueous medium, preferably, ion-exchanged water and an emulsifier, first, the monomer mixture A as it is or in an emulsified state is collectively or divided into or continuously added or added dropwise to the reaction vessel, the presence of a polymerization initiator, Te than a gauge pressure in the range of about ^{1kg / cm 2 ~100kg / cm 2} , and about 50 ° C. ~ The polymerization is carried out at a reaction temperature within a range of 150 ° C., and first, an emulsion polymer A is prepared.

Next, in the presence of the polymer A thus obtained, the monomer mixture B is also placed in the reaction vessel, as it is, or in an emulsified state, collectively, dividedly or continuously. The polymerization may be carried out in the presence of the polymerization initiator at a reaction temperature in the range of about 50 ° C. to 100 ° C. and at an arbitrary pressure. In the present invention, depending on the case, it goes without saying that there is no problem even if the pressure is higher than this or the temperature is lower than this.

Here, the ratio of the monomer mixture A to the monomer mixture B is 30 to 9 of the monomer mixture A.
A mixing ratio of 70 to 10 parts by weight of the monomer mixture B to 0 parts by weight is appropriate. In this case, the ratio between the core and the shell is the same as the charge ratio,
While the core is in the range of 30 to 90 parts by weight, the shell is in the range of 70 to 10 parts by weight, whereby a core-shell type polymer emulsion having such a ratio is obtained.

It is necessary that the amount of the fluorine atom-containing monomers composed of only chlorotrifluoroethylene contained in the total monomers be approximately 30% by weight or more. If it is less than this, satisfactory results cannot be obtained in terms of the so-called durability of the finally obtained film.

The ratio of the total amount of monomers to water is such that the final solid content is 1 to 60% by weight, preferably 15% by weight.
The range of about 55% by weight is appropriate, but the ratio should be set to such a ratio.

Further, in carrying out the emulsion polymerization of the monomer mixture A, in order to grow or control the particle diameter, the emulsion particles may be allowed to exist in an aqueous phase before polymerization. Of course.

As the water in the aqueous medium used here, it is basically appropriate to use ion-exchanged water, but the amount of such water must be 70% by weight or more in the aqueous medium. It is. Here, an organic solvent may be used together with the remaining less than 30% by weight. Here, the organic solvent is not particularly limited, and any general-purpose organic solvent can be used.

As the organic solvents, only typical ones are exemplified, and various ketones such as acetone, methyl ethyl ketone and methyl amyl ketone; various esters such as ethyl acetate and butyl acetate; Various aromatic hydrocarbons such as benzene, toluene and xylene; various aliphatic hydrocarbons such as hexane and heptane; various alcohols such as methanol, ethanol, isopropanol and butanol; carbon tetrachloride, methylene So-called halogen-containing organic solvents containing various chlorofluorocarbon solvents such as dichloride and hexafluoroisopropanol.

In the polymerization reaction, when the pH in the system is approximately 1.0
The pH may be adjusted by using a so-called pH buffer such as disodium phosphate or borax, or sodium bicarbonate or ammonia. Just do it. Under a pH condition higher than this, when a film is formed, only a film having a so-called lack of durability, such as water resistance and alkali resistance, can be obtained, which is a cause of deterioration in various performances.

In this way, the core-shell type polymer emulsion of the present invention is obtained. The state of the system after the completion of the reaction is such that unreacted gaseous monomers are extremely contained in the emulsion particles. Partly, it is surviving. Most of such residual monomers are unreacted fluoroolefin monomers, but in order not to destroy the emulsion, and to remove it stably,
You should do the following:

That is, after neutralizing all or a part of the acidic groups based on the acid group-containing monomers converted into the polymer with the basic substance, the unreacted monomers are removed. Or after adding a silicon compound and / or a mineral oil compound, unreacted monomers may be removed.

As the basic substances mentioned here, only typical ones are exemplified.
Hydroxides of alkali metals such as potassium hydroxide; various organic amines such as triethylamine; and ammonia. Of these, particularly preferred are organic amines such as triethylamine and ammonia. And volatile base materials.

Further, the above-mentioned silicon compound and / or
Alternatively, as the mineral oil-based compound, a known and commonly used aqueous defoaming agent may be used.

As a method for removing unreacted monomers, unreacted gaseous monomers may be removed at room temperature or under a heating condition of 100 ° C. or less under normal pressure or reduced pressure. By removing the creatures,
It can also be by using a steam distillation method or the like. At this time, a so-called inert gas such as nitrogen gas is bubbled into the system to promote the removal of unreacted gaseous monomers.
The effect of the removal can be increased.

The core-shell type polymer emulsion of the present invention, or the core-shell type polymer emulsion obtained by the method of the present invention, has a number-average molecular weight in terms of a number-average molecular weight in terms of having no crosslinkable monomers. , 5,000
The range of 0 to 1,000,000 is appropriate, and the weight average molecular weight is 10,000 to 3,000,000.
00 is appropriate, and the minimum film forming temperature is suitably in the range of about 0 ° C to 60 ° C. Further, as the particle diameter of the core-shell polymer, generally,
A range of 0.02 to 0.5 microns (μm) is appropriate.

The core-shell type polymer emulsion according to the present invention can be further blended with a thickener, a film-forming auxiliary, etc., to form a coating for building exterior materials. As the thickener used in this case, a cellulose thickener represented by hydroxyethylcellulose, carboxymethylcellulose and the like; a urethane thickener; and a polycarboxylic acid thickener can be used.

Examples of the above-mentioned film-forming assistants include, in addition to the above-mentioned various solvents, ester-based or ether-based derivatives of ethylene glycol; or ester-based or ether-based derivatives of diethylene glycol; Alternatively, various plasticizers, such as “Texanol” (a product of Eastman Chemical Co., USA), commonly used for water-based paints can be used.

In addition to these, titanium oxide, mica,
Various inorganic pigments such as talc, clay, precipitated barium sulfate, silica powder, calcium carbonate, iron oxide, zinc oxide, aluminum powder, and carbon black; various organic pigments such as azo, phthalocyanine, and quinacridone Or plastic pigments; or these various pigments can be used in the form of a dispersion pigment dispersed in water with an emulsifier or dispersant, depending on the final purpose. , As appropriate.

Further, various additives necessary for forming a coating material include, for example, dispersants, wetting agents, thixotropic agents, ultraviolet absorbers, antioxidants, water repellents, and antifreeze agents. The use of antiseptic, antiseptic or antifoaming agents is appropriately selected and used in consideration of various properties of the obtained film.

Thus, a coating for building exterior materials containing a core-shell type polymer emulsion can be obtained. There is no particular limitation on applying such a coating for building exterior materials to a base material for building exterior. As an example, brush coating, roller coating, spray coating, roll coater coating, or showering coating is preferably used.

At this time, for construction site construction, it is desirable to use a paint having a minimum film-forming temperature of 0 ° C. or less with a film-forming aid added. The coating method is a brush, roller or spray. It is better to use such a method, and for roofing and wall materials, such as tiles, for so-called factory line painting, according to the general heating and forced drying method, and according to the drying conditions. It is desirable to select and use a coating material having a minimum film forming temperature of about 60 ° C. or lower, preferably 50 ° C. or lower, in a state in which the film forming aids are added. The coating method includes a roll coater and a roller. ,
It is preferable to use a method such as spraying, showering, flow coater, or dip coating such as dipping.

Regardless of whether it is for on-site construction or for factory line painting or forcibly drying by heating, drying by room temperature is, of course, one method, but by any means, a temperature of 60 ° C. or more, substantially In order to carry out in an atmosphere at a temperature of 200 ° C. or less, after coating, if necessary, after setting time, by heating and drying, the film forming property or film forming property can be further strengthened. In order to ensure the long-term durability of the film,
It is also desirable to reduce the blocking as much as possible and also to ensure stain resistance.

In addition, the above-mentioned paint for architectural exterior material, or a paint for architectural exterior material containing a pigment or the like, is directly coated on the base material with one coat or in multiple coats. Thus, it may be applied, or, acrylic copolymer, acrylic-styrene copolymer system, acrylic-urethane combined system, silicon-acryl combined system, epoxy system,
A coating material containing a binder, such as a urethane-based or silicon-based material, which generally has good alkali resistance, was coated with a primer, and then a top coat was coated with a coating for architectural exterior materials. You may make it aim at improvement and improvement, such as weather resistance.

In any of the above coating systems, a paint for architectural exterior materials containing a core-shell type polymer emulsion as an essential film-forming component, or a paint for architectural exterior materials containing pigments and the like. The dry film thickness is preferably 5 μm or more.

When the thickness is less than 5 μm, the long-term durability of the film tends to be insufficient.

Thus, according to the present invention or according to the method of the present invention, various film properties such as super weather resistance, water resistance, chemical resistance and stain resistance are excellent.
A protective film of the substrate is formed.

The base material in the present invention includes, for example, cement mortar, cement concrete, AL
Particularly typical is a hardened material (concrete frame, wall material or roof material) prepared by hydrating and crystallizing an alkaline substance, such as C, asbestos concrete, wood cement board, or calcium silicate board. It is. In addition to these substrates, it can be applied to metals, plastics, woods, glasses, papers, fibers, and the like.

The core-shell type polymer emulsion according to the present invention is characterized by being excellent in the weather resistance, chemical resistance, and stain resistance of the coating film, and the long-term boiling water resistance and the alkali resistance at high temperatures. Therefore, it can be widely used as an aqueous coating composition for exterior use, and further as an exterior coating agent for metals, plastics, woods, inorganic base materials, papers, fibers and the like.

[0088]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, comparative examples, applied technical examples and comparative applied technical examples. In the following, all parts and percentages are all unless otherwise specified. It shall be based on weight.

Example 1 (Preparation Example of Core-Shell Fluororesin Aqueous Dispersion) A stainless steel pressure-resistant reaction equipped with a stirrer, a nitrogen inlet tube, a thermometer and a temperature controller and having an inner volume of 2 liters (l) The container (autoclave) is filled with nitrogen gas,
The system was sufficiently replaced, and 800 g of ion-exchanged water, 20 g of sodium dodecylbenzenesulfonate, 20 g of polyoxyethylene nonylphenyl ether, and 10 g of borax as a pH buffer were added and dissolved.

Next, 200 g of vinyl neononanoate was added.
10 g of crotonic acid and 5 g of octadiene were further added to 300 g of liquefied chlorotrifluoroethylene.
g was also charged, and ethylene gas was injected until the pressure reached 15 kg / cm ² .

The internal temperature of the autoclave was raised to 80 ° C. At this time, the pressure in the system during the reaction is approximately 25
The ethylene gas was adjusted to be kg / cm ² .

At the same temperature, 3 g of potassium persulfate was added to 10 g
An aqueous catalyst solution dissolved in 0 g of ion-exchanged water was pressed into the reaction vessel over 2 hours. After the addition of the catalyst aqueous solution, the polymerization temperature was maintained at the same temperature for 4 hours to continue the polymerization reaction, thereby obtaining a polymer emulsion having a fluorine atom.

Next, 280 g of vinyl neodecanoate and 20 g of crotonic acid were charged into the reaction vessel.
Thereafter, ethylene gas was injected until the pressure became 30 kg / cm ² , and the internal temperature of the autoclave was raised to 80 ° C. At this time, the pressure in the system during the reaction is almost
Ethylene gas was adjusted to be 30 kg / cm ² .

Subsequently, at the same temperature, an aqueous catalyst solution obtained by dissolving 2 g of potassium persulfate in 100 g of ion-exchanged water was pressed into the reaction vessel over 2 hours. After addition of the catalyst aqueous solution, the temperature is maintained for 10 hours at the same temperature,
The polymerization reaction was allowed to continue.

The reaction was allowed to proceed at a pH of 3.5. During this reaction, as the monomer was consumed, the pressure in the system decreased. In each case, the pressure of the reaction system was maintained at 30 kg / cm ² by introducing ethylene.

After completion of the reaction, the mixture is cooled to room temperature and
Ammonia water was added until the pH became approximately 7.5, and 1 g of a 5% aqueous dispersion of “NOPCO 8034L” [a silicon-based defoaming agent manufactured by San Nopco] was added. Stirred.

Next, unreacted gas was gradually taken out of the system, and the pressure in the system was returned to normal pressure.

Thereafter, unreacted gas dissolved in the dispersion was distilled off under reduced pressure. The dispersion obtained here has a nonvolatile content of 50.2%, a pH of 7.2,
The minimum film forming temperature is 43 ° C. and the average particle size is 0.09
μm, a white core-shell type polymer emulsion. Hereinafter, this is abbreviated as (A-1).

(A-1) was analyzed by elemental analysis, ion chromatography analysis, infrared absorption spectrum and compositional analysis by pyrolysis gas chromatography to find that the content of the fluoroolefin monomer was about 30% by weight. It was confirmed that there was.

Example 2 (Preparation Example of Core-Shell Fluororesin Aqueous Dispersion) A 2-liter stainless steel pressure-resistant reaction vessel (autoclave) equipped with a stirrer, a nitrogen inlet tube, a thermometer and a temperature controller was filled with nitrogen gas. Thus, after sufficiently replacing the system,
800 g of ion-exchanged water, 20 g of sodium dodecylbenzenesulfonate, 20 g of polyoxyethylene nonylphenyl ether, and 10 g of borax as a pH buffer were added and dissolved.

Then, 2-ethylhexanoate vinyl 2
30 g, 10 g of crotonic acid, 10 g of tris (2-methoxyethoxy) vinylsilane, and 350 g of chlorotrifluoroethylene collected by liquefaction were further charged, and ethylene gas was injected until the pressure reached 15 kg / cm ² .

[0102] The internal temperature of the autoclave was raised to 80 ° C. At this time, the pressure in the system during the reaction is approximately 25
The ethylene gas was adjusted to be kg / cm ² .

At the same temperature, 3 g of potassium persulfate was added to 10 g
An aqueous catalyst solution dissolved in 0 g of ion-exchanged water was pressed into the reaction vessel over 2 hours. After the addition of the catalyst aqueous solution, the polymerization temperature was maintained at the same temperature for 4 hours to continue the polymerization reaction, thereby obtaining a polymer emulsion having a fluorine atom.

Next, into this reaction vessel, 210 g of neodecanoic acid and 20 g of crotonic acid were injected.
Ethylene gas was injected until the pressure reached 30 kg / cm ² . The internal temperature of the autoclave was raised to 80 ° C. At this time, the internal pressure during the reaction was approximately 30 kg /
The ethylene gas was adjusted so as to be cm ² .

Thereafter, at the same temperature, an aqueous catalyst solution obtained by dissolving 2 g of potassium persulfate in 100 g of ion-exchanged water was pressed into the reaction vessel over 2 hours. Even after the addition of the catalyst aqueous solution, the polymerization reaction was continued at the same temperature for 10 hours.

The pH during the reaction proceeded at 3.5. During the reaction, the pressure in the system decreased as the monomers were consumed. In each case, the pressure of the reaction system was maintained at 30 kg / cm ² by introducing ethylene.

After completion of the reaction, the reaction mixture is cooled to room temperature and
% Ammonia water was added until the pH became approximately 7.5, and 1 g of a 5% aqueous dispersion of "Nopco 8034L" was further added, followed by thorough stirring.

Next, unreacted gas was gradually taken out of the system, and the pressure in the system was returned to normal pressure.

Thereafter, unreacted gas dissolved in the dispersion was distilled off under reduced pressure. The resulting dispersion is a white core-shell polymer emulsion having a nonvolatile content of 50.0%, a pH of 7.4, a minimum film-forming temperature of 18 ° C., and an average particle size of 0.1 μm. Met.
Hereinafter, this is abbreviated as (A-2).

This (A-2) was analyzed by elemental analysis, ion chromatography, infrared absorption spectrum and compositional analysis by pyrolysis gas chromatography to show that the content of the fluoroolefin monomer was about 35% by weight. Was confirmed.

Comparative Example 1 (Preparation Example of Polymer Emulsion of Uniform Composition) A 2-liter stainless steel pressure-resistant reaction vessel (autoclave) equipped with a stirrer, a nitrogen inlet tube, a thermometer and a temperature controller was purged with nitrogen gas. After sufficiently replacing the inside of the system, 800 g of ion-exchanged water, 20 g of sodium dodecylbenzenesulfonate, 20 g of polyoxyethylene nonylphenyl ether, and 10 g of borax as a pH buffer were added and dissolved.

Then, 200 g of vinyl nonanoate, 280 g of vinyl neodecanoate, 5 g of octadiene and 30 g of crotonic acid were charged, and 300 g of liquefied and collected chlorotrifluoroethylene were also charged.

Subsequently, ethylene gas was supplied at 15 kg / c.
Press-fit until m ² . Autoclave internal temperature 80
° C, where the pressure in the system during the reaction is almost
Ethylene gas was adjusted to be 30 kg / cm ² .

At the same temperature, 5 g of potassium persulfate was added.
Was dissolved in 200 g of ion exchanged water,
It was pressed into the reaction vessel for 3 hours. After addition of the catalyst aqueous solution, the temperature is maintained for 10 hours at the same temperature,
The polymerization reaction was continued to obtain a control polymer emulsion in which the fluorine atoms were uniformly contained in the particles. The pH during the reaction proceeded at 3.5.

During the reaction, the pressure in the system decreased as the monomers were consumed. Each time, the pressure in the reaction system was maintained at 30 kg / cm ² by introducing ethylene.

After the completion of the reaction, the mixture is cooled to room temperature and
% Ammonia water is added until the pH becomes approximately 7.5, 1 g of a 5% aqueous dispersion of "Nopco 8034L" is added, and the mixture is stirred well.
The system was gradually removed from the system and the internal pressure was returned to normal pressure.

Next, unreacted gas dissolved in the dispersion was distilled off under reduced pressure. The control dispersion obtained here had a nonvolatile content of 50.2% and a pH of 7.2.
The minimum film forming temperature is 45 ° C. and the average particle diameter is 0.1.
It was a white core-shell polymer emulsion having a thickness of 08 µm. Hereinafter, this is abbreviated as (B-1).

This (B-1) was analyzed by elemental analysis, ion chromatographic analysis, infrared absorption spectrum, and compositional analysis by pyrolysis gas chromatography to find that the content of the fluoroolefin monomer was about 30% by weight. Was confirmed.

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

Examples 4 and 5 and Comparative Example 2 These examples were prepared by using various fluororesin aqueous dispersions obtained in Examples 1 and 2 and Comparative Example 1, respectively, for paints for building exterior materials. And for each,
Evaluation of various performances was conducted.

First, the above-mentioned aqueous dispersions of various fluororesins were diluted so that the nonvolatile content became 45%, and an aqueous dispersion paste of titanium oxide (titanium oxide content = 70%) was prepared.
Formulated so that the pigment volume concentration (PVC) is 15%,
A 3% aqueous solution of hydroxyethylcellulose as a thickener is added separately to increase the viscosity by 2% each, and "Texanol" as a film-thickening aid is added separately to each other by 2%. Various paints for building exterior materials were obtained.

Next, the coating material for building exterior material thus obtained was applied on a slate plate using a No. 60 bar coater, and dried at 60 ° C. for 20 minutes. Thereafter, the specimen was dried at room temperature for 7 days to produce various specimens. And for each specimen,
Various performance evaluation tests were performed. The results of these tests are summarized in Table 1.

[0128]

[Table 1]

<< Footnotes to Table 1 >><Test Items and Evaluation Criteria> “Mitsuzawa Value”: A 60-degree gloss value obtained using a Murakami gloss meter. It shows that the dispersibility is good.

"Adhesiveness" ... The dried coating film was immersed in tap water for 5 hours, and then dried at room temperature for 1 day. Then, a goth adhesion test was performed, and the film was peeled off with cellophane tape, and the degree of peeling of the coating film was visually determined.

◎: No external appearance defect ×: Coating peeled off

"Accelerated weathering resistance": Abbreviation of "accelerated weathering resistance": After performing a test for 3,000 hours using a dual panel light control weather meter, the appearance of each coating film was visually judged. did.

A: No abnormality in appearance. B: Gloss is observed in the coating. X: Blistering, peeling, and whitening are observed in the coating.

The core-shell type fluororesin aqueous dispersion (polymer emulsion) according to the present invention has good pigment dispersibility without impairing weather resistance as compared with a control product having a uniform composition.
In addition, it can be seen that the adhesion to the substrate also gives a good film or coating.

[0135]

As described above, the aqueous dispersion of the core-shell type fluororesin (fluoroolefin copolymer emulsion) according to the present invention has more localized fluorine atoms than the aqueous fluororesin dispersion having a uniform composition. Thus, the present invention provides a paint for a building exterior material in which the acid content of the pigment is good and the adhesion to the base material is also good, without impairing the weather resistance.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 259/00-259/08

Claims (8)

(57) [Claims] (1) The inside of the particle is chlorotrifluoroethylene.
While it is occupied by the resin derived from the fluorine atom-containing monomers consisting only of the resin, the outer shell of the particles is occupied by the resin derived from the monomer having no fluorine atom. Aqueous dispersion of core-shell type fluororesin for building exterior materials . 2. The aqueous dispersion of a core-shell type fluororesin for a building exterior material according to claim 1, wherein the monomer having no fluorine atom contains vinyl carboxylate as an essential component. 3. In preparing an aqueous resin dispersion by radical polymerization in an aqueous medium in the presence of an emulsifier, chlorotrifluoroethylene is prepared as a first step .
Polymerizing a monomer mixture containing a fluorine atom-containing monomer consisting of only an essential component to obtain an aqueous dispersion of a fluororesin, as a second step, in the presence of the aqueous dispersion of the fluororesin Characterized by polymerizing a monomer mixture containing a monomer having no fluorine atom as an essential component,
A method for producing an aqueous dispersion of a core-shell type fluororesin for a building exterior material . 4. The aqueous dispersion of a core-shell type fluororesin for a building exterior material according to claim 3, wherein the monomers to be polymerized in the second step are those containing vinyl carboxylate as an essential component. How to make the body. 5., characterized in that it contains as an essential film-forming component an aqueous dispersion of Koashi <br/> E le type fluororesin for exterior building material according to claim 1, building exterior material coatings. 6. A building exterior material comprising the core-shell type aqueous fluororesin dispersion for building exterior material obtained by the production method according to claim 3 or 4 as an essential film-forming component . Paint . 7. The coating material for building exterior materials according to claim 5, further comprising a thickener and a film-thickening aid as essential components. 8. A building according to any one of claims 5 to 7.
Architectural exterior materials that have been coated with an exterior paint and dried.