JP2015196118A - Active vibration control coating film, and manufacturing method therefor - Google Patents

Abstract

Disclosed is a vibration-damping coating film that exhibits excellent vibration damping properties. A vibration-damping coating film formed on a substrate, the coating film being on the side opposite to the side in contact with the substrate rather than the hardness of the coating surface on the side in contact with the substrate A vibration-damping coating film having a high surface hardness and a difference in hardness of two or more pencil hardnesses. The thickness of the vibration-damping coating film is 2 to 8 mm, and the coating film is a vibration-damping coating film that is a coating film obtained from a damping material composition comprising an acrylic emulsion and a crosslinking agent. . [Selection figure] None

Description

The present invention relates to a vibration-damping coating film and a method for producing the same. More specifically, the present invention relates to a vibration-damping coating film used for preventing vibration and noise in various structures and maintaining quietness, and a manufacturing method thereof.

The damping material is for keeping vibration and noise in various structures and keeping quiet, for example, in addition to being used under the indoor floor of an automobile, a railway vehicle, a ship, an aircraft, an electrical device, Widely used in building structures and construction equipment. As a material used for such a damping material, conventionally, a molded product such as a plate-shaped molded body or a sheet-shaped molded body made of a material having vibration absorption performance and sound absorption performance has been used. Application type damping material (paint) has been developed as an alternative material for processed products. For example, a coating film formed by spraying or applying an arbitrary method to a corresponding part by a spraying method, vibration absorption effect and Various damping coatings capable of obtaining a sound absorbing effect have been proposed.

Conventional coating-type vibration damping materials include water-based paints (see Patent Document 1) having vibration damping properties containing a heat-expandable organic hollow filler at a predetermined ratio, water-based resin emulsions, inorganic fillers, and water retention. An aqueous coating type vibration damping material containing at least microballoon particles that start expansion under a heating temperature condition below the boiling point of water with an expansion agent while encapsulating an expansion agent that volatilizes and expands by heating with the agent ( Patent Document 2) is disclosed. In addition, an emulsion-type paint with a specified paint solid content, pigment volume concentration, and volume concentration of a large particle size pigment with a specified particle size is applied to a specified coating thickness and dried under specified conditions to apply coating type damping A method of forming a coating film of a material is disclosed (see Patent Document 3).

JP 7-145331 A JP 2010-1111746 A JP 2010-58070 A

As described above, various types of coating-type damping materials are known. The demand for coating-type damping materials that can easily form a coating film on a substrate having a complicated shape has been increasing year by year, and the damping properties required for the coating film formed in this way have become even higher. ing.

This invention is made | formed in view of the said present condition, and aims at providing the damping coating film which exhibits the outstanding damping property.

The inventor conducted various studies on the vibration-damping coating film exhibiting excellent vibration damping properties, and found that the vibration-damping coating film formed on the base material was determined based on the hardness of the coating film surface on the side in contact with the base material. If the surface of the coating film opposite to the side in contact with the substrate has a pencil hardness of 2 or more levels, it is found that the coating film has excellent vibration damping properties. The present inventors have arrived at the present invention.

That is, the present invention is a vibration-damping coating film formed on a substrate, wherein the coating film is a coating on the side opposite to the side in contact with the substrate rather than the hardness of the coating surface on the side in contact with the substrate. It is a vibration-damping coating film characterized in that the film surface has a high hardness and the difference in hardness is two or more in pencil hardness.
The present invention is described in detail below.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

<1. Damping coating film>
The vibration-damping coating film of the present invention has a higher hardness on the surface of the coating film opposite to the side in contact with the substrate than the hardness of the coating film surface on the side in contact with the substrate, and the difference in hardness is 2 in pencil hardness. It is a coating film at a stage or higher. The difference in altitude is preferably 3 or more in pencil hardness. More preferably, there are four or more stages. The vibration-damping coating film of the present invention may be composed of a single layer or may be a laminate of a plurality of layers. When the vibration-damping coating film of the present invention is a laminate of a plurality of layers, the above-mentioned "coating surface on the side opposite to the side in contact with the substrate" is the coating film of the uppermost layer of the laminated layers Means surface.
The hardness of the coating film surface on the side in contact with the base material was peeled off from the base material by performing a release treatment such as applying a release agent on the base material in advance or stretching a release film such as a tetron film. The surface can be measured according to JIS K5400-8-4. The coating film surface on the side opposite to the side in contact with the substrate can be measured in the same manner.

In the vibration-damping coating film of the present invention, the hardness of the coating film surface on the side in contact with the substrate is preferably 8B to 6H in pencil hardness. More preferably, it is 6B-4H, More preferably, it is 4B-3H.
Moreover, it is preferable that the hardness of the coating-film surface on the opposite side to the side which contact | connects a base material is 6B-8H in pencil hardness. More preferably, it is 4B-8H, More preferably, it is 2B-8H.
Considering the application in which the vibration-damping coating film of the present invention is used, the hardness of the coating film surface on the side in contact with the substrate and the hardness of the coating film surface on the side opposite to the side in contact with the substrate are in such a range. It is preferable that it exists in.

The vibration-damping coating film of the present invention preferably has a thickness of 2 to 8 mm. In consideration of exhibiting more sufficient vibration damping properties, preventing the occurrence of blistering of the coating film and forming a good coating film, such a thickness is preferable. The thickness of the vibration-damping coating film is more preferably 2 to 6 mm, and still more preferably 3 to 6 mm.
When the vibration-damping coating film of the present invention is a laminate of a plurality of layers, the total thickness of the laminated layers is preferably in the above range.
The film thickness of the coating film can be measured with calipers.

The vibration-damping coating film of the present invention preferably has a glass transition temperature of 10 to 50 ° C. after drying. In order for the coating film to exhibit excellent vibration damping properties, it is necessary that the coating film is not too hard, and if the glass transition temperature of the coating film after drying the vibration damping coating is such a temperature, it is practical. Excellent vibration damping can be achieved in the temperature range. Since the glass transition temperature of the coating film of the vibration damping coating is affected by the content of components other than the polymer such as the pigment in addition to the glass transition temperature of the polymer contained in the vibration damping coating, By adjusting the content of the components, the glass transition temperature of the vibration-damping paint can be adjusted to the above-mentioned preferable range. The glass transition temperature of the coating film after drying is more preferably 15 to 45 ° C, and further preferably 20 to 40 ° C.
The glass transition temperature of the coating film after drying of the vibration-damping paint can be measured by the method described in Examples using a dynamic viscoelasticity measuring apparatus RSA-III (manufactured by TA Instruments) described in Examples.

The vibration-damping coating film of the present invention is particularly suitable for a composition that forms a coating film as long as the coating film surface in contact with the substrate and the coating film surface on the opposite side satisfy the above-mentioned predetermined requirements. Although it does not restrict | limit, It is preferable that it is a coating film obtained from the damping material compound containing a polymer emulsion and a crosslinking agent.

The monomer component that is a raw material of the polymer (polymer (A)) forming the polymer emulsion in the present invention is not particularly limited as long as the effects of the present invention can be exhibited, but the unsaturated carboxylic acid single amount The body is preferably included. More preferably, it comprises an unsaturated carboxylic acid monomer and another monomer copolymerizable with the unsaturated carboxylic acid monomer. The unsaturated carboxylic acid monomer is not particularly limited as long as it is a compound having an unsaturated bond and a carboxyl group in the molecule, but preferably contains an ethylenically unsaturated carboxylic acid monomer.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited. For example, (meth) acrylic acid, crotonic acid, itaconic acid, citraconic acid, fumaric acid, maleic acid, maleic anhydride, monomethyl fumarate, monoethyl One type or two or more types of unsaturated carboxylic acids such as fumarate, monomethyl maleate, monoethyl maleate, or derivatives thereof may be used. Among these, (meth) acrylic acid monomers such as (meth) acrylic acid are preferable. That is, the polymer (polymer (A)) forming the polymer emulsion is a (meth) acrylic polymer in which at least one of the monomer components is a (meth) acrylic acid monomer, One of preferred embodiments of the present invention, wherein the vibration-damping coating film of the present invention comprises an acrylic emulsion which is an emulsion of a (meth) acrylic polymer and a crosslinking agent. It is one of the preferred embodiments of the present invention that the coating film is obtained from the above.

The (meth) acrylic polymer is a polymer obtained from a monomer component containing a (meth) acrylic acid monomer and / or a (meth) acrylic monomer.
Here, the (meth) acrylic acid monomer has an acryloyl group or a methacryloyl group, or a group in which a hydrogen atom in these groups is replaced with another atom or atomic group, and a -COOH group. The (meth) acrylic monomer has an acryloyl group or a methacryloyl group, or a group in which a hydrogen atom in these groups is replaced with another atom or atomic group, and- A monomer in the form of a COOH group in the form of an ester or salt, or a derivative of such a monomer.

As said (meth) acrylic-type polymer, what is obtained using the monomer component containing a (meth) acrylic-acid type monomer is preferable. In the (meth) acrylic polymer, at least one of the monomer components is C (R ⁴ ) ₂ ═CH—COOR ⁵ or C (R ⁶ ) ₂ ═C (CH ₃ ) —COOR ^7. (R ⁴ , R ⁵ , R ⁶ and R ⁷ are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group or an organic amine group). Is preferably obtained.

The monomer component used as the raw material for the (meth) acrylic polymer is 0.1 to 20% by mass of the (meth) acrylic acid monomer with respect to 100% by mass of the total monomer components, and other common components. It preferably contains 80 to 99.9% by mass of a polymerizable ethylenically unsaturated monomer. By including the (meth) acrylic acid monomer, the dispersibility of the filler such as inorganic powder is improved in the vibration damping composition containing the acrylic emulsion, and the vibration damping is further improved. become. Moreover, by having a functional group, a crosslinked structure can be formed later using a crosslinking agent, and the coating film hardness can be increased.
Moreover, it becomes easy to adjust the acid value, Tg, physical properties, etc. of a polymer by including another copolymerizable ethylenically unsaturated monomer. In the monomer component, if the (meth) acrylic acid monomer is 0.1% by mass or more and 20% by mass or less, the monomer component is stably copolymerized. The coating film formed from the vibration damping composition containing the (meth) acrylic polymer has excellent vibration damping properties due to the synergistic effect of the monomer units formed from these monomers. In addition to being able to exhibit it, the coating film appearance is also excellent.
More preferably, 0.5 to 3% by mass of the (meth) acrylic acid monomer and 100 to 97% to 99% of other copolymerizable ethylenically unsaturated monomers with respect to 100% by mass of all monomer components. .5% by mass.
Other copolymerizable ethylenically unsaturated monomers include (meth) acrylic monomers other than (meth) acrylic acid monomers, unsaturated monomers having aromatic rings, and nitrogen atoms Examples thereof include unsaturated monomers and other monomers copolymerizable with (meth) acrylic acid monomers.

Examples of the (meth) acrylic monomer include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, pentyl acrylate, pentyl methacrylate, isoamyl acrylate, isoamyl methacrylate, hexyl acrylate, hexyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, octyl acrylate, octyl methacrylate, isooctyl acrylate, isooctyl Methacrylate, nonyl acrylate, nonyl methacrylate, isononyl acrylate, isononyl methacrylate, decyl acrylate, decyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, vinyl formate, vinyl acetate, vinyl propionate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, diallyl phthalate, triallylcia Nurate, ethylene grease Diacrylate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, diethylene glycol Dimethacrylate, allyl acrylate, allyl methacrylate, etc .; salts and esterified products of (meth) acrylic monomers other than these may be mentioned, and it is preferable to use one or more of these.

The salt is preferably a metal salt, ammonium salt, organic amine salt or the like. Examples of the metal atom forming the metal salt include monovalent metal atoms such as alkali metal atoms such as lithium, sodium and potassium; divalent metal atoms such as alkaline earth metal atoms such as calcium and magnesium; aluminum, Trivalent metal atoms such as iron are preferred. Further, as the organic amine salt, an alkanolamine salt such as an ethanolamine salt, a diethanolamine salt, or a triethanolamine salt, or a triethylamine salt is preferable.

As a monomer component used as the raw material of the said (meth) acrylic-type polymer, it contains 20 mass% or more of (meth) acrylic-type monomers with respect to 100 mass% of all monomer components. It is preferable. More preferably, it is 30 mass% or more.

Examples of the unsaturated monomer having an aromatic ring include divinylbenzene, styrene, α-methylstyrene, vinyltoluene, and ethylvinylbenzene. Styrene is preferred.
That is, the (meth) acrylic polymer forming the acrylic emulsion is a styrene (meth) acrylic polymer obtained from a monomer component containing styrene. One.

When the polymer (polymer (A)) forming the polymer emulsion is a (meth) acrylic polymer having an aromatic ring, the unsaturated monomer having an aromatic ring with respect to 100% by mass of all monomer components. It is preferable to contain 1 to 70% by mass of the monomer. More preferably, it is 5-60 mass%, More preferably, it is 10-40 mass%. In addition, it is not necessary to use the unsaturated monomer which has an aromatic ring as a monomer component used as the raw material of the said (meth) acrylic-type polymer.

The polymer (polymer (A)) forming the polymer emulsion is also preferably obtained from a monomer component containing a polar group-containing monomer. When the polymer (A) has a polar group, the interaction between the polymers in the damping material becomes larger, and the friction between the polymers becomes larger, so that the damping performance is more fully exhibited. Become.
The polar group contained in the polar group-containing monomer is not particularly limited as long as it is generally a polar group in an organic compound, and examples thereof include a hydroxyl group, a carboxyl group, and a nitrile group. Preferably, it is a carboxyl group.

Other monomers copolymerizable with the above (meth) acrylic acid monomer include polyfunctional allyl monomers such as trimethylolpropane diallyl ether, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, and diethylene glycol mono And vinyl ether monomers such as vinyl ether.

The damping composition in the present invention may contain one type of polymer (polymer (A)) forming a polymer emulsion, or may contain two or more types. Further, the polymer (A) may be composed of two or more kinds of polymers, and they may be combined. In addition, when the polymer (A) is in a form having a core part and a shell part to be described later, the polymer (A) is composed of two types of polymers, and one of the two types of polymers is a core part, The other may form the shell part. For example, the unsaturated carboxylic acid monomer and the other monomer copolymerizable with the unsaturated carboxylic acid monomer are a monomer component that forms the core part of the emulsion and a monomer component that forms the shell part. It may be contained in any of these, and may be used for both of them.

Moreover, it is preferable that at least 1 type in the polymer which forms a polymer emulsion is a form of the emulsion particle which has a core part and a shell part. Thereby, the interface between polymers can be increased and effects, such as a vibration damping improvement, can be enlarged.

When the polymer emulsion in the present invention includes emulsion particles having a core part and a shell part, the core part and the shell part may be completely compatible with each other and may have a homogeneous structure in which they cannot be distinguished. A core-shell composite structure or microdomain structure that is not completely compatible but heterogeneously formed may be used, but among these structures, the characteristics of the emulsion are fully exploited to produce a stable emulsion. Therefore, a core / shell composite structure is preferable.
An emulsion having a core-shell composite structure is excellent in vibration damping properties in a wide range within a practical temperature range. Especially in the high temperature range, it exhibits excellent vibration damping performance compared to other forms of vibration damping composition. As a result, within the practical temperature range, the vibration damping performance covers a wide range from room temperature to high temperature range. Can be demonstrated.
In the core / shell composite structure, the surface of the core part is preferably covered with the shell part. In this case, it is preferable that the surface of the core part is completely covered with the shell part, but it may not be completely covered. For example, the core part may be covered in a mesh shape or in some places. The part may be exposed.

The polymer (polymer (A)) forming the polymer emulsion preferably has a glass transition temperature of -20 to 40 ° C. When a polymer (A) having such a glass transition temperature is used, the vibration damping performance in the practical temperature range of the vibration damping material can be effectively expressed. The glass transition temperature of the polymer (A) is more preferably -15 to 35 ° C, still more preferably -10 to 30 ° C.
The glass transition temperature (Tg) may be determined based on the knowledge already obtained, and may be controlled by the type and use ratio of the monomer component described later. It can be calculated from the following formula (1).

In the formula, Tg ′ is Tg (absolute temperature) of the polymer. W ₁ ′, W ₂ ′,... Wn ′ are mass fractions of the respective monomers with respect to the total monomer components. T ₁ , T ₂ ,... Tn are glass transition temperatures (absolute temperatures) of homopolymers (homopolymers) composed of the respective monomer components.

When at least one of the polymers (A) is in the form of emulsion particles having a core part and a shell part, the glass transition temperature of the polymer in the core part is preferably 0 to 60 ° C. More preferably, it is 10-50 degreeC.
The glass transition temperature of the polymer in the shell part is preferably -30 to 30 ° C. More preferably, it is -20-20 degreeC.
Moreover, it is preferable that the difference of the glass transition temperature of the polymer of a core part and the polymer of a shell part is 5-60 degreeC. By providing a difference in the glass transition temperature in this way, for example, when applied to a damping material application, it becomes possible to express higher damping properties under a wide temperature range, which is a practical range in particular. The vibration damping property in the ˜60 ° C. region will be further improved. The difference in glass transition temperature is more preferably 5 to 50 ° C, still more preferably 5 to 40 ° C.

When at least one of the polymers (polymer (A)) forming the polymer emulsion is in the form of emulsion particles having a core part and a shell part, the monomer component forming the core part and the shell part are formed. The mass ratio with respect to the monomer component (monomer component forming the core portion / monomer component forming the shell portion) is preferably 30/70 to 70/30. With such a mass ratio, the effect of being a structure having a core portion and a shell portion can be more fully exhibited. The mass ratio of the monomer component forming the core part and the monomer component forming the shell part is more preferably 35/65 to 55/45.

The polymer (A) preferably has a weight average molecular weight of 20,000 to 800,000. In order to exhibit vibration damping properties, it is preferable to change the vibrational energy applied to the polymer to thermal energy due to friction, and a polymer that can move when vibration is applied to the polymer. It is necessary to be. When the polymer (A) has such a weight average molecular weight, the polymer can sufficiently move when vibration is applied, and high damping properties can be exhibited. The weight average molecular weight of the polymer (A) is more preferably 30,000 to 400,000.

The weight average molecular weight (Mw) can be determined by GPC (gel permeation chromatography) measurement under the following measurement conditions.
Measuring instrument: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)
Molecular weight column: TSK-GEL GMHXL-L and TSK-GELG5000HXL (both manufactured by Tosoh Corporation) are connected in series. Eluent: Tetrahydrofuran (THF)
Standard material for calibration curve: Polystyrene (manufactured by Tosoh Corporation)
Measurement method: The measurement object is dissolved in THF so that the solid content is about 0.2% by mass, and the molecular weight is measured using an object obtained by filtration through a filter as a measurement sample.

The average particle diameter of the emulsion particles in the polymer emulsion is preferably 80 to 450 nm.
By using emulsion particles with an average particle size in this range, the basic properties such as coating film appearance and coating properties required for vibration damping materials will be sufficient, and vibration damping will be even better. It can be. The average particle diameter of the emulsion particles is more preferably 400 nm or less, still more preferably 350 nm or less. The average particle diameter is more preferably 100 nm or more.
The average particle size (volume average particle size) was determined by diluting the emulsion with distilled water, thoroughly stirring and mixing, then collecting about 10 ml in a glass cell, and measuring the particle size distribution by a dynamic light scattering method (Particle Sizing Systems). It can obtain | require by measuring by "NICOMP Model 380" by a company.

The emulsion particles having the above average particle diameter preferably have a particle size distribution defined by a value obtained by dividing the standard deviation by the volume average particle diameter (standard deviation / volume average particle diameter × 100) of 40% or less. More preferably, it is 30% or less. When the particle size distribution is 40% or less, coarse particles are not included, and as a result, the vibration damping composition can exhibit sufficient heat drying properties.

The crosslinking agent contained in the vibration-damping composition in the present invention is one that can form a crosslinked structure in the polymer (A) that forms the polymer emulsion, or that can form a crosslinked structure alone. That's fine. As what can form a crosslinked structure in the polymer (A) which forms a polymer emulsion, zinc oxide, calcium hydroxide, oxazoline, carbodiimide, etc. are mentioned. Examples of crosslinking agents that can form a crosslinked structure include polyfunctional (meth) acrylate monomers such as ethylene glycol dimethacrylate and trimethylolpropane triacrylate, trimethylolpropane diallyl ether, and pentaerythritol triallyl ether. Examples thereof include polyfunctional allyl monomers and polyfunctional vinyl ether monomers such as diethylene glycol divinyl ether.
These 1 type (s) or 2 or more types can be used. The vibration damping composition contains a cross-linking agent, and the cross-linking reaction is sufficiently advanced in the vicinity of the coating surface opposite to the substrate to increase the hardness of the coating surface. The appearance is excellent.
The blending ratio of the crosslinking agent is preferably 0.1 to 10 parts by mass and more preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the solid content of the vibration damping composition.

As long as it contains a polymer emulsion and a crosslinking agent, the vibration damping composition in the present invention may contain other components or may contain a neutralizing agent.
The neutralizing agent is not particularly limited, and examples thereof include tertiary amines such as triethanolamine, 2-methylaminoethanol, dimethylethanolamine, diethylethanolamine and morpholine; diglycolamine, aqueous ammonia; sodium hydroxide and the like. Can be used. These may be used alone or in combination of two or more. Among these, it is preferable to use a volatile base that volatilizes when the coating film is heated. More preferably, an amine having a boiling point of 80 ° C. or higher, particularly 80 to 360 ° C. is used because heat drying properties are improved and vibration damping properties are improved. As such a neutralizing agent, for example, tertiary amines such as triethanolamine, dimethylethanolamine, diethylethanolamine, morpholine, and diglycolamine are preferable. More preferably, an amine having a boiling point of 130 to 280 ° C is used. In addition, the said boiling point is a boiling point in a normal pressure.
The molecular weight of the neutralizing agent is not particularly limited, but is preferably 130 to 280 from the viewpoint of volatility.
Furthermore, it is preferable to add the neutralizing agent so that the neutralizing agent is 0.6 to 1.4 equivalents with respect to 1 equivalent of the acid group of the polymer contained in the polymer emulsion. . More preferably, it is 0.8-1.2 equivalent.

The vibration damping composition of the present invention may further contain other components. Examples of other components include pigments, foaming agents, thickeners, solvents, fillers, gelling agents, dispersants, antifoaming agents, coloring agents, rust preventive pigments, plasticizers, stabilizers, wetting agents, and antiseptics. Agents, antifoaming agents, antiaging agents, antifungal agents, ultraviolet absorbers, antistatic agents, and the like, and one or more of these can be used.
In addition, the said other component can be mixed with the said damping composition etc. using a butterfly mixer, a planetary mixer, a spiral mixer, a kneader, a dissolver etc., for example.

As said pigment, 1 type (s) or 2 or more types, such as the coloring agent mentioned later and a rust preventive pigment, can be used, for example. As a compounding quantity of the said pigment, it is preferable to set it as 0.2-700 mass parts with respect to 100 mass parts of solid content of a damping composition, More preferably, it is 100-550 mass parts.

As the foaming agent, for example, a low-boiling hydrocarbon encapsulated heated expansion capsule, an organic foaming agent, an inorganic foaming agent, and the like are suitable, and one or more of these can be used. Examples of the heated expansion capsule include Matsumoto Microsphere F-30, F-50 (manufactured by Matsumoto Yushi Co., Ltd.); EXPANSELL WU642, WU551, WU461, DU551, DU401 (manufactured by Nippon Expandcel). Examples of the organic foaming agent include azodicarbonamide, azobisisobutyronitrile, N, N-dinitrosopentamethylenetetramine, p-toluenesulfonylhydrazine, p-oxybis (benzenesulfohydrazide), and the like. Examples of the foaming agent include sodium bicarbonate, ammonium carbonate, silicon hydride and the like.
As a compounding quantity of the said foaming agent, it is preferable to set it as 0.2-3.0 mass parts with respect to 100 mass parts of solid content of a damping composition, More preferably, 0.3-2.0 mass parts It is.

Examples of the thickener include polyvinyl alcohol, cellulose derivatives, polycarboxylic acid resins, and the like. As a compounding quantity of a thickener, it is preferable to set it as 0.01-2 mass parts by solid content with respect to 100 mass parts of solid content of a damping composition, More preferably, it is 0.05-1.5 mass. Part, more preferably 0.1 to 1 part by weight.

Examples of the solvent include ethylene glycol, butyl cellosolve, butyl carbitol, butyl carbitol acetate, and the like. What is necessary is just to set suitably as a compounding quantity of a solvent so that the solid content density | concentration of the emulsion composition for damping materials in the thick film coating composition for heat-drying may become the range mentioned above.

Examples of the filler include inorganic fillers such as calcium carbonate, kaolin, silica, talc, barium sulfate, alumina, iron oxide, titanium oxide, glass talk, magnesium carbonate, aluminum hydroxide, talc, diatomaceous earth, and clay; glass Examples of the inorganic filler include flakes and mica; and fibrous inorganic fillers such as metal oxide whiskers and glass fibers.
As a compounding quantity of a filler, it is preferable to set it as 50-800 mass parts with respect to 100 mass parts of solid content of a damping composition, More preferably, it is 200-700 mass parts.
When the thickness of the coating film is increased, the vibration damping performance can be improved, and a high vibration damping property can be obtained at a low cost by blending an inexpensive filler.

As said filler, a thing with an average particle diameter of 1-50 micrometers is preferable.
The average particle diameter of the filler can be measured by a laser diffraction particle size distribution measuring device, and is a value of 50% diameter by weight from the particle size distribution.

Examples of the gelling agent include starch and agar.
Examples of the dispersant include inorganic dispersants such as sodium hexametaphosphate and sodium tripolyphosphate, and organic dispersants such as polycarboxylic acid-based dispersants.
Examples of the antifoaming agent include silicon-based antifoaming agents.
Examples of the colorant include organic or inorganic colorants such as titanium oxide, carbon black, dial, hansa yellow, benzine yellow, phthalocyanine blue, and quinacridone red.
Examples of the rust preventive pigment include a metal phosphate, a metal molybdate, and a metal borate.

Although it does not specifically limit as pH of the said damping material compound, It is preferable that it is 2-10, More preferably, it is 3-9.5, More preferably, it is 7-9. The pH of the polymer emulsion can be adjusted by adding ammonia water, water-soluble amines, alkali hydroxide aqueous solution and the like to the resin.
In this specification, pH can be measured with a pH meter. For example, it is preferable to measure the value at 25 ° C. using a pH meter (“F-23” manufactured by Horiba, Ltd.).

Although it does not specifically limit as a viscosity of the said damping material compound, It is preferable that it is 1-10000 mPa * s, More preferably, it is 5-5000 mPa * s. Among them, more preferably, it is 5 to 2000 mPa · s, and further preferably 5 to 1500 mPa · s. Among them, more preferably, it is 5 to 1000 mPa · s, and particularly preferably 5 to 500 mPa · s. Especially preferably, it is 10-500 mPa * s, More preferably, it is 20-500 mPa * s, Most preferably, it is 50-500 mPa * s.
The viscosity can be measured using a B-type rotational viscometer under the conditions of 25 ° C. and 30 min ⁻¹ .

Although the manufacturing method in particular of the said polymer emulsion is not restrict | limited, For example, it can manufacture by the method similar to the manufacturing method of the emulsion for damping materials of Unexamined-Japanese-Patent No. 2011-231184.

The substrate for forming the vibration-damping coating film of the present invention is not particularly limited as long as the coating film can be formed, and may be any metal material such as a steel plate, plastic material, or the like. Among them, since the vibration-damping coating film of the present invention is used for various structures such as automobiles, railway vehicles, ships, aircrafts, and electrical equipment, it is not possible to form a coating film on the surface of a steel plate that is a material for these materials. It is one of the preferable usage forms of the vibration-damping coating film of the present invention.
Such a steel plate with a vibration damping material characterized in that a vibration damping coating film is formed on the surface is also one aspect of the present invention.
The steel plate with the vibration damping material of the present invention may be any steel as long as the vibration-damping coating film of the present invention is formed on at least a part of the steel sheet. In addition to the vibration-damping coating film of the present invention, the present invention Another coating film that does not correspond to the vibration-damping coating film may be formed. Two or more types of coating film corresponding to the vibration-damping coating film of the present invention may be formed on the steel plate.

<2. Manufacturing method of vibration-damping coating film>
The present invention is also a method for producing a vibration-damping coating film, which comprises a polymer, a crosslinking agent, and a neutralizing agent, and has a pH-dependent crosslinking composition for forming a crosslinked structure. And a step of forming a coating film by coating the base material on the substrate, and a step of forming a non-uniform cross-linking structure in the coating film by making the concentration of the neutralizing agent in the coating film non-uniform. It is also the manufacturing method (henceforth the manufacturing method of the 1st damping film of this invention) of dampening film which becomes.
In the first method for producing a vibration-damping coating film of the present invention, there is a difference between the hardness of the coating film surface on the side in contact with the substrate and the hardness of the coating film surface on the side opposite to the side in contact with the substrate. This is a preferred method for producing a vibration-damping coating film of the present invention.

The first method for producing a vibration-damping coating film according to the present invention is a method for forming a coating film having a non-uniform crosslinked structure using a pH-dependent crosslinking composition. The pH-dependent crosslinkable composition is a composition in which the degree of progress of the cross-linking reaction is affected by the pH, and the first method for producing a vibration-damping coating film is as follows: In this method, the concentration of the neutralizing agent in the coating film is made non-uniform so as to make the pH non-uniform and form a non-uniform crosslinked structure.
The first method for producing a vibration-damping coating film of the present invention comprises applying a crosslinkable composition having a pH dependency on the formation of a crosslinked structure on a substrate, which contains a polymer, a crosslinking agent, and a neutralizing agent. Other steps may be included as long as it includes a step of forming a coating film and a step of making the concentration of the neutralizing agent in the coating film non-uniform and forming a non-uniform crosslinked structure in the coating film. Further, a step of forming another coating film may be included.

The method for making the neutralizing agent concentration in the coating film non-uniform is not particularly limited, but a method of volatilizing a part of the neutralizing agent in the coating film is preferable. By this method, the neutralizing agent concentration in the coating film can be easily made non-uniform. Specifically, it is possible to use a method in which a temperature difference is generated depending on a site in the coating film so that a difference is caused in the degree of volatilization of the neutralizing agent.
When forming a coating film with a different degree of cross-linking structure between the coating surface on the substrate side and the coating surface on the opposite side of the substrate, the coating surface on the substrate side is opposite to the substrate. The method of heating so that a temperature difference may arise with the coating-film surface of the side can be used.

When using the method of volatilizing a part of neutralizing agent in the said coating film, it is preferable to make the coating film formed by apply | coating a crosslinkable composition on a base material at 80-200 degreeC. By setting it at such temperature, it is preferable to dry the coating film and volatilize the neutralizing agent in the coating film at the same time. More preferably, it is 90-180 degreeC, More preferably, it is 100-170 degreeC.
Moreover, it is preferable that the time which makes a coating film the said temperature is 10 to 240 minutes. More preferably, it is 20 to 180 minutes, and particularly preferably 30 to 120 minutes.
In order to make the coating film excellent in vibration damping properties and coating film appearance, it is necessary to allow a sufficient crosslinking reaction to proceed in the vicinity of the coating film surface opposite to the substrate. Some degree of heating is required to advance the crosslinking reaction, but if the heating temperature is high, the water remaining inside the coating film boils violently, and the coating film may swell to deteriorate the appearance of the coating film. There is. The heating temperature and time are preferable heating conditions considering that both the vibration damping properties and the appearance of the coating film are excellent.

The pH-dependent crosslinkable composition is not particularly limited as long as it contains a polymer, a crosslinking agent, and a neutralizing agent and causes a difference in the progress of the crosslinking reaction depending on the pH. A composition containing a cross-linking agent that causes a difference in the degree of progression and a composition containing an oxidative curable monomer can be suitably used. When an oxidation-curing monomer is used, the curing reaction proceeds more in the vicinity of the coating surface on the side that comes into contact with the air (the coating surface on the side opposite to the substrate), so the coating surface on the substrate side is opposite to the substrate. A difference in hardness is generated in the coating film with the coating film surface on the side.
The pH-dependent crosslinkable composition is more preferably a composition containing the above-described polymer emulsion. More preferably, it is a composition containing the acrylic emulsion mentioned above.

As the crosslinking agent that causes a difference in the progress of the crosslinking reaction depending on the pH, one or more of zinc oxide, calcium hydroxide, oxazoline, carbodiimide and the like are preferably used. Among these, zinc oxide and oxazoline are preferable.
The blending ratio of the crosslinking agent that causes a difference in the progress of the crosslinking reaction depending on the pH is 0.1 to 20 parts by mass with respect to 100 parts by mass of the solid content of the pH-dependent crosslinking composition. Preferably, it is 0.2-10 mass parts.

As the above-mentioned oxidatively curable monomer, one kind of a polyfunctional allyl monomer such as trimethylolpropane diallyl ether, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, or the like, or a dicyclopentadiene monomer such as dicyclopentenyloxy methacrylate, or the like Two or more are preferably used. Among these, polyfunctional allylic monomers are preferable.
The blending ratio of the above-mentioned oxidation-curable monomer is preferably 1 to 40% by mass with respect to 100% by mass of the monomer component that is a raw material of the polymer contained in the pH-dependent crosslinking composition, It is more preferable that it is 2-20 mass%.

The neutralizing agent contained in the pH-dependent crosslinking composition includes tertiary amines such as triethanolamine, 2-methylaminoethanol, dimethylethanolamine, diethylethanolamine, morpholine; monoethanolamine, diglycolamine One type or two or more types such as aqueous ammonia are preferably used. Since these neutralizing agents are volatilized at the temperature normally used for drying the coating film, by using these neutralizing agents, the neutralizing agent in the coating film is volatilized simultaneously with the drying of the coating film. Can be made.
Among these, tertiary amines such as triethanolamine, 2-methylaminoethanol, dimethylethanolamine, diethylethanolamine and morpholine are preferable.
The blending ratio of the neutralizing agent is preferably 0.1 to 10 parts by mass, and 0.2 to 5 parts by mass with respect to 100 parts by mass of the solid content of the pH-dependent crosslinkable composition. More preferably.

The pH-dependent crosslinkable composition may contain components other than the polymer, the crosslinking agent, and the neutralizing agent. Other components are the same as the other components other than the neutralizing agent, the crosslinking agent and the (meth) acrylic polymer included in the above-described vibration damping composition in the present invention, and the preferable blending ratio is also the same.

The present invention is also a method for producing a vibration-damping coating film, which comprises a step of applying a first damping material composition on a substrate to form a first coating film; On the first coating film, a second crosslinkable composition comprising a polymer and a crosslinking agent, which is different from the first damping material composition, is applied, and what is the first coating film? A method for producing a vibration-damping coating film (hereinafter also referred to as a second method for producing a vibration-damping coating film of the present invention), which comprises a step of forming a second coating film having a different surface hardness. is there.
Such a method for producing the second vibration-damping coating film of the present invention is also a suitable method for producing the vibration-damping coating film of the present invention.
As long as the manufacturing method of the 2nd damping coating film of this invention includes the process of forming a 1st coating film, and the process of forming a 2nd coating film, the process of forming another coating film May be included.

The manufacturing method of the 2nd damping coating film of this invention may include the process of drying these coating films in addition to the process of forming a 1st coating film, and the process of forming a 2nd coating film. preferable. In the second method for producing a vibration-damping coating film of the present invention, the first coating film may be formed and dried, and then the second coating film may be formed and dried. After forming the coating film and the second coating film, these coating films may be dried at once. More preferably, after forming the first coating film and the second coating film, these coating films are dried at once. That is, it is preferable to perform the process of drying a coating film after performing the process of forming a 1st coating film, and the process of forming a 2nd coating film.
When the manufacturing method of the second vibration-damping coating film includes a step of forming a third coating film (third coating film or later), the drying process performs a process of forming all coating films. It is preferable to dry all the formed coating films at once.
In the second method for producing a vibration-damping coating film of the present invention, the preferable temperature and time for drying the coating film are the same as those in the first method for producing a vibration-damping coating film of the present invention. It is the same as the temperature and time when a part of the neutralizing agent is volatilized.

As the first vibration damping composition, a composition containing the above-described polymer emulsion is suitable. The first vibration damping composition may or may not contain a crosslinking agent.
As the second crosslinkable composition, the above-described vibration damping composition (a vibration damping composition containing a polymer emulsion and a crosslinking agent) in the present invention can be suitably used.
As the first vibration-damping compound and the second vibration-damping compound, those prepared as appropriate are used so that the surface hardness of the first coating film differs from that of the second coating film. be able to.

In the first and second methods for producing a vibration-damping coating film of the present invention, a method for forming a coating film of a vibration-damping composition or a crosslinkable composition on a substrate is not particularly limited. A method of applying using a spatula, an air spray, an airless spray, a mortar gun, a ricin gun or the like can be used.

The preferable film thickness of the vibration-damping coating film formed by the first and second vibration-damping coating film manufacturing methods of the present invention is the same as the preferable film thickness of the above-described vibration-damping coating film of the present invention. .

The vibration damping properties of the vibration damping coating film formed by the vibration damping coating film of the present invention and the first and second vibration damping coating film manufacturing methods of the present invention measure the loss factor of the film. Can be evaluated.
The loss factor is usually expressed by η and indicates how much the vibration applied to the damping material is attenuated. The loss factor indicates that the higher the numerical value, the better the damping performance.
As a method for measuring the loss factor, a resonance method for measuring near the resonance frequency is generally used, and there are a half width method, an attenuation rate method, and a mechanical impedance method. In the present invention, the loss factor of the vibration-damping coating film is preferably measured by a resonance method (3 dB method) using a cantilever method. The measurement using the cantilever method can be performed using, for example, a CF-5200 FFT analyzer manufactured by Ono Sokki Co., Ltd.

Since the vibration-damping coating film of the present invention has the above-described configuration and exhibits excellent vibration-damping properties, materials such as steel plates constituting various structures such as automobiles, railway vehicles, ships, aircraft, and electrical equipment A coating film can be formed on the surface of the film and used suitably.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

In the following production examples, various physical properties and the like were evaluated as follows.
<Average particle size>
The volume average particle diameter of the emulsion particles was measured using a particle size distribution measuring apparatus (“NICOMP Model 380” manufactured by Particle Sizing Systems) by a dynamic light scattering method.
<Nonvolatile content (N.V.)>
About 1 g of the obtained emulsion was weighed, and after 110 hours at 110 ° C. with a hot air dryer, the remaining amount after drying was regarded as a non-volatile content, and the ratio to the mass before drying was expressed in mass%.
<PH>
The value at 25 ° C. was measured with a pH meter (“F-23” manufactured by Horiba, Ltd.).
<Viscosity>
Using a B-type rotational viscometer (“VISCOMETER TUB-10” manufactured by Toki Sangyo Co., Ltd.), the measurement was performed at 25 ° C. and 20 rpm.

<Weight average molecular weight>
It measured by GPC (gel permeation chromatography) on the following measurement conditions.
Measuring instrument: HLC-8120GPC (trade name, manufactured by Tosoh Corporation)
Molecular weight column: TSK-GEL GMHXL-L and TSK-GELG5000HXL (both manufactured by Tosoh Corporation) are connected in series. Eluent: Tetrahydrofuran (THF)
Standard material for calibration curve: Polystyrene (manufactured by Tosoh Corporation)
Measurement method: The measurement object is dissolved in THF so that the solid content is about 0.2% by mass, and the molecular weight is measured using an object obtained by filtration through a filter as a measurement sample.

<Glass glass transition temperature (Tg)>
The Tg of the polymer was calculated from the monomer composition used in each stage using the following calculation formula (1).

In addition, Tg calculated from the monomer composition used in all stages was described as “total Tg”.
The Tg values of the respective homopolymers used to calculate the glass transition temperature (Tg) of the polymerizable monomer component by the above calculation formula (1) are shown below.
Methyl methacrylate (MMA): 105 ° C
Styrene (St): 100 ° C
Butyl acrylate (BA): -56 ° C
2-ethylhexyl acrylate (2EHA): -70 ° C
Acrylic acid (AA): 95 ° C

Production Example 1
285 parts of deionized water was charged into a polymerization vessel equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel. Thereafter, the internal temperature was raised to 75 ° C. while stirring under a nitrogen gas stream. On the other hand, 170 parts of styrene, 130 parts of methyl methacrylate, 95 parts of butyl acrylate, 95 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, 3.0 parts of t-dodecyl mercaptan which is a polymerization chain transfer agent, 20% in advance A first-stage monomer emulsion consisting of 90 parts of emulsifier Hytenol 18E (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 97 parts of deionized water prepared in an aqueous solution was charged. Next, while maintaining the internal temperature of the polymerization vessel at 80 ° C., 11 parts of the above monomer emulsion, 6.6 parts of 3% potassium persulfate aqueous solution which is a polymerization initiator (oxidant), and 2% 5.0 parts of an aqueous sodium hydrogen sulfite solution was added to initiate initial polymerization. After 20 minutes, the remaining monomer emulsion was uniformly added dropwise over 120 minutes while maintaining the inside of the reaction system at 80 ° C. At the same time, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 120 minutes, and the same temperature was maintained for 60 minutes after completion of the addition. Next, in the dropping funnel 60 parts of styrene, 140 parts of methyl methacrylate, 190 parts of butyl acrylate, 100 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, 3.0 parts of t-dodecyl mercaptan, Haitenol adjusted to a 20% aqueous solution in advance A second-stage monomer emulsion consisting of 75 parts of 18E (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 100 parts of deionized water was charged and added dropwise uniformly over 120 minutes. At the same time, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 120 minutes. After completion of the addition, the same temperature was maintained for 90 minutes to complete the polymerization. After cooling the resulting reaction liquid to room temperature, 25 parts of 2-dimethylethanolamine was added, and the nonvolatile content was 54.9%, pH 7.9, viscosity 360 mPa · s, average particle diameter of emulsion 190 nm, weight average molecular weight 51000, An emulsion 1 having a first stage Tg of 16 ° C., a second stage Tg of −13 ° C., and a total Tg of 0 ° C. was obtained.

Production Example 2
285 parts of deionized water was charged into a polymerization vessel equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel. Thereafter, the internal temperature was raised to 75 ° C. while stirring under a nitrogen gas stream. On the other hand, 350 parts of styrene, 40 parts of butyl acrylate, 100 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, 2.5 parts of t-dodecyl mercaptan which is a polymerization chain transfer agent, an emulsifier previously adjusted to a 20% aqueous solution. A first-stage monomer emulsion consisting of 90 parts of Latemul 118B (trade name, manufactured by Kao) and 97 parts of deionized water was charged. Next, while maintaining the internal temperature of the polymerization vessel at 80 ° C., 11 parts of the above monomer emulsion, 6.6 parts of 3% potassium persulfate aqueous solution which is a polymerization initiator (oxidant), and 2% 5.0 parts of an aqueous sodium hydrogen sulfite solution was added to initiate initial polymerization. After 20 minutes, the remaining monomer emulsion was uniformly added dropwise over 120 minutes while maintaining the inside of the reaction system at 80 ° C. At the same time, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 120 minutes, and the same temperature was maintained for 60 minutes after completion of the addition. Next, Lathemul 118B (trade name, Kao), which was prepared by adding 150 parts of styrene, 200 parts of butyl acrylate, 140 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, 2.5 parts of t-dodecyl mercaptan and 20% aqueous solution in a dropping funnel. (Manufactured) A second-stage monomer emulsion consisting of 75 parts and 100 parts of deionized water was charged and added dropwise uniformly over 120 minutes. At the same time, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 120 minutes. After completion of the addition, the same temperature was maintained for 90 minutes to complete the polymerization. After cooling the obtained reaction liquid to room temperature, 25 parts of 2-dimethylethanolamine was added, non-volatile content 55.0%, pH 8.2, viscosity 290 mPa · s, average particle diameter of emulsion 200 nm, weight average molecular weight 65000, Emulsion 2 having a first stage Tg of 31 ° C., a second stage Tg of −28 ° C., and a total Tg of 1 ° C. was obtained.

Production Example 3
285 parts of deionized water was charged into a polymerization vessel equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel. Thereafter, the internal temperature was raised to 75 ° C. while stirring under a nitrogen gas stream. On the other hand, 340 parts of methyl methacrylate, 100 parts of butyl acrylate, 50 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, 1.0 part of t-dodecyl mercaptan, which is a polymerization chain transfer agent, were previously adjusted to a 20% aqueous solution. A first-stage monomer emulsion consisting of 90 parts of emulsifier Latemul 118B (trade name, manufactured by Kao) and 97 parts of deionized water was charged. Next, while maintaining the internal temperature of the polymerization vessel at 80 ° C., 11 parts of the above monomer emulsion, 6.6 parts of 3% potassium persulfate aqueous solution which is a polymerization initiator (oxidant), and 2% 5.0 parts of an aqueous sodium hydrogen sulfite solution was added to initiate initial polymerization. After 20 minutes, the remaining monomer emulsion was uniformly added dropwise over 120 minutes while maintaining the inside of the reaction system at 80 ° C. At the same time, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 120 minutes, and the same temperature was maintained for 60 minutes after completion of the addition. Next, 200 parts of methyl methacrylate, 200 parts of 2-ethylhexyl acrylate, 20 parts of acrylic acid, 1.0 part of t-dodecyl mercaptan, 75 parts of Latemuru 118B (trade name, manufactured by Kao) previously adjusted to a 20% aqueous solution in a dropping funnel And a second-stage monomer emulsion consisting of 100 parts of deionized water was added dropwise uniformly over 120 minutes. At the same time, 80 parts of a 3% potassium persulfate aqueous solution and 30 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 120 minutes. After completion of the addition, the same temperature was maintained for 90 minutes to complete the polymerization. After cooling the resulting reaction liquid to room temperature, 25 parts of 2-diethylethanolamine was added, and the nonvolatile content was 55.1%, pH 8.0, viscosity 500 mPa · s, average particle diameter of emulsion 180 nm, weight average molecular weight 132000, An emulsion 3 having a first stage Tg of 33 ° C., a second stage Tg of −18 ° C., and a total Tg of 5 ° C. was obtained.

Specific contents of each trade name used in the above Production Examples 1 to 3 are as follows.
<Emulsifier>
* Hightenol 18E: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl ether ammonium sulfate (anionic)
* Latemuru 118B: manufactured by Kao Corporation, sodium polyoxyethylene alkyl ether sulfate (anionic)

Example 1
100 parts of the emulsion 1 obtained in Production Example 1, 2.0 parts of zinc oxide, and 250 parts of calcium carbonate (NN # 200, manufactured by Nitto Flour Chemical Co., Ltd., average particle diameter 20 μm) as a filler are mixed. A vibration damping composition 1 was obtained.
A vibration-damping coating film was formed on the base material using the obtained damping material composition 1 and dried at 130 ° C., and various properties described in Table 1 were evaluated. Evaluation methods for various properties are shown below.

Examples 2 to 6, Comparative Examples 1 and 2
A coating film was formed on the base material using the damping material formulations 2 to 6 and the comparative damping material formulations 1 and 2 produced by changing the blending as shown in Table 1, and the drying temperatures listed in Table 1 After drying, the various characteristics were evaluated in the same manner as the vibration damping composition 1. The results are shown in Table 1. In each of the damping material formulations 2 to 6 and the comparative damping material formulations 1 and 2, the blending amount of the emulsion is 100 parts.
In Table 1, “TMPDAE” means trimethylolpropane diallyl ether.

Example 7
As shown in Table 2, two types of damping material blends were produced, a first coating film was formed on the substrate, and a second coating film was further formed on the first coating film. Then, after drying these coating films at a drying temperature of 130 ° C., various characteristics were evaluated in the same manner as the vibration damping composition 1. The results are shown in Table 2. The amount of the emulsion of the vibration damping composition 7 is 100 parts.

<Evaluation of coating surface hardness>
On the Teflon (trademark) board (100 mm width x 150 mm length x thickness 2 mm), the prepared vibration damping composition was applied so that the coating film thickness of the composition was 4 mm. Then, it dried for 50 minutes at the drying temperature of Table 1 using the hot-air drying furnace, peeled the dry coating film from the Teflon (trademark) board, and was left to stand in 25 degreeC atmosphere for 1 hour. Thereafter, the coating film hardness was measured according to the pencil scratch value of JIS K5400-8-4. The weight of the weight was 500 g, and the evaluation was made based on whether or not the surface was scratched even a little.
According to the following Table 3, the hardness was scored and evaluated based on the following criteria from the hardness difference between the surface of the coating film in contact with the substrate and the surface of the coating film on the side opposite to the substrate.
◎: Hardness difference 4 or more ○: Hardness difference 3
Δ: Hardness difference 2
X: Hardness difference 1 or less

<Vibration suppression test>
The prepared damping material composition was applied to a cold rolled steel plate (SPCC, width 15 mm × length 250 mm × thickness 1.5 mm) with a thickness of 3 mm, dried at 150 ° C. for 30 minutes, and then onto the cold rolled steel plate. A damping material film having an areal density of 4.0 kg / m ² was formed. The vibration damping property was measured by a resonance method (3 dB method) at 20 ° C., 40 ° C. and 60 ° C. using a cantilever method (loss factor measurement system, Ono Sokki Co., Ltd.). The greater the loss factor, the better the vibration damping.

<Appearance evaluation of coating film>
On the steel plate (SPCC-SD, width 75 mm × length 150 mm × thickness 0.8 mm: manufactured by Nippon Test Panel Co., Ltd.), the prepared damping material composition was applied so that the coating film thickness of the composition was 4 mm. . Then, it dried for 50 minutes using the hot air dryer, and evaluated the surface condition of the obtained dry coating film on the following references | standards.
○: No abnormality (no swelling or cracks in the coating film)
Δ: Dandruff and cracks are found in various places of the coating film ×: Dandruff and cracks are seen throughout the coating film

Claims (6)

A vibration-damping coating film formed on a substrate, wherein the coating film has a hardness on the surface of the coating film opposite to the side in contact with the substrate rather than the hardness of the coating film surface on the side in contact with the substrate. A vibration-damping coating film that is high and has a hardness difference of two or more pencil hardnesses. The vibration-damping coating film according to claim 1, wherein the vibration-damping coating film has a thickness of 2 to 8 mm. The vibration-damping coating film according to claim 1 or 2, wherein the vibration-damping coating film is a coating film obtained from a damping material composition comprising an acrylic emulsion and a crosslinking agent. . A steel plate with a damping material, wherein the damping coating film according to any one of claims 1 to 3 is formed on a surface. A method for producing a vibration-damping coating film, the production method comprising:
A step of forming a coating film by applying a crosslinkable composition having a pH dependency on the formation of a crosslinked structure, including a polymer, a crosslinking agent and a neutralizing agent;
And a step of making the concentration of the neutralizing agent in the coating film non-uniform, and forming a non-uniform cross-linked structure in the coating film. A method for producing a vibration-damping coating film, the production method comprising:
Applying a first damping material formulation on a substrate to form a first coating;
On the first coating film, a second crosslinkable composition comprising a polymer and a crosslinking agent, which is different from the first damping material composition, is applied, and what is the first coating film? And a step of forming a second coating film having a different surface hardness.