JP2017186388A - Heat-foamable emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material capable of forming a coating film which has good heating drying property, has excellent appearance, and can exhibit excellent vibration-damping properties even when used as a vibration-damping material.SOLUTION: A heat-foamable emulsion composition contains an emulsion polymer, where the emulsion polymer has a storage elastic modulus at 70°C and 1 Hz when dymanic viscoelasticity is measured of 5.0×10Pa or more, the composition further contains a surfactant component, and the surfactant component has a lamellar length at 55°C in 1.0 mass% aqueous solution larger than a lamellar length at 20°C.SELECTED DRAWING: None

Description

The present invention relates to a heat-foamable emulsion composition, and more specifically, includes a heat-foamable emulsion composition that can be suitably used for various structures that require vibration damping, and the heat-foamable emulsion composition. The present invention relates to a paint and a coating film obtained using the paint.

In recent years, emulsion compositions have been used to form coatings that perform various functions in the manufacture of many industrial products in consideration of environmental protection, workability during coating formation, safety for industrial products, etc. ing. For example, foamable emulsion compositions that foam (mechanical foaming) by stirring or the like and exhibit a desired function have been proposed (see, for example, Patent Documents 1 to 3).
By the way, in recent years, vibration damping properties have attracted attention as one of new functions, and emulsion compositions are also used for vibration damping materials.

Damping materials are used to prevent vibrations and noise of various structures and keep quiet. They are used under the interior floors of automobiles, as well as railway vehicles, ships, aircraft, electrical equipment, and building structures. Widely used for construction and construction equipment. As a damping material, a plate-shaped or sheet-shaped molded product made of a material having vibration absorption performance and sound absorption performance has been used, but as an alternative, a coating film using an emulsion composition is used. Various paints have been proposed that can obtain a vibration absorption effect and a sound absorption effect by forming (see, for example, Patent Documents 4 to 7).

JP 62-124137 A JP 2011-184637 A JP2013-1891A JP 2007-85385 A Japanese Patent No. 5159628 JP 2013-199531 A Japanese Patent No. 56607779

In the coating material containing the emulsion composition, water is volatilized after application and the emulsion particles are fused to form a coating film. From the viewpoint of efficiency, it is conceivable to heat dry (baked) the applied paint, but in that case, especially when the film thickness is thick, a film is formed from the surface of the paint film, so-called skinning occurs, Since the water in the coating film is difficult to escape during drying, the heat drying property is not good. Thus, if heat drying property is bad and a favorable coating film is not formed, while the external appearance of a coating film will be inferior, it will become impossible to fully express desired functions, such as vibration damping.

Various paints have been proposed as described above, but it is preferable to form a coating film that has good heat drying properties, excellent appearance, and can exhibit excellent vibration damping properties when used as a vibration damping material. No paint has been found yet.

The present invention has been made in view of the above-mentioned present situation, and it is possible to suitably form a coating film that has good heat drying properties, excellent appearance, and can exhibit excellent vibration damping properties when used as a vibration damping material. It aims at providing the paint which can be performed.

This inventor examined various materials with good heat drying property, and paid attention to the heat foamable emulsion composition. By using the heat-foamable emulsion composition, foaming occurs at the time of heat-drying to form a water evaporation path, which may improve the heat-dryability of the paint. Next, the present inventor has studied various methods for suitably adjusting the foaming properties, and as a result, in the emulsion composition, the physical properties of the emulsion polymer and the surfactant component under high temperature conditions are important. I found it. For example, by using a surfactant component having a lamellar length under a high temperature condition that is larger than a lamellar length under a normal temperature condition, bubbles are not only generated during heating and drying, but the bubbles can be stabilized. Further, by setting the storage elastic modulus of the emulsion polymer under a high temperature condition to be within a predetermined numerical range, the shape of the foam generated at the time of heat drying can be maintained in an appropriate shape. Then, the present inventor uses a novel heat-foamable emulsion composition in which both the storage elastic modulus of the emulsion polymer under high temperature conditions and the lamellar length under high temperature conditions of the surfactant component are specified. The present inventors have arrived at the present invention by conceiving that the above-mentioned problems can be satisfactorily solved by improving the heat-drying property.

That is, the present invention is a heat-foamable emulsion composition containing an emulsion polymer, and the emulsion polymer has a storage elastic modulus of 5.0 × 10 ³ at 70 ° C. and 1 Hz when dynamic viscoelasticity is measured. The composition further includes a surfactant component, and the surfactant component has a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution thereof is larger than a lamellar length at 20 ° C. It is a heat-foamable emulsion composition.
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.

<The heat-foamable emulsion composition of the present invention>
That the heat-foamable emulsion composition of the present invention contains the surfactant component is that the emulsion polymer is obtained by emulsion polymerization, and the composition is used by using all of the components during emulsion polymerization. The composition may contain a component, or a part of the component may be used at the time of emulsion polymerization, and the rest of the component may be added to the obtained emulsion polymer so that the composition contains the component. The composition may contain the component by forming the emulsion polymer by the component acting on a polymer polymerized by a method other than emulsion polymerization. Among these, from the viewpoint of making the effect of the present invention remarkable, the heat-foamable emulsion composition of the present invention is an emulsion polymer obtained by emulsion polymerization, and all or one of the components during emulsion polymerization is obtained. By using parts, the composition preferably contains the component. Moreover, when using this component at the time of emulsion polymerization, this component may be a normal surfactant (a compound different from the emulsion polymer), and is a structural unit constituting a part of the polymer forming the emulsion polymer. Although it may be, it is more preferably a compound different from the emulsion polymer.
In the present specification, the emulsion polymer refers to a polymer that forms emulsion particles in the heat-foamable emulsion composition.

Using the heat-foamable emulsion composition of the present invention, a coating film that is excellent in appearance and can exhibit a desired function, for example, excellent damping properties in a wide temperature range when used for damping materials Can get to.
The reason why it is possible to suitably obtain a coating film that is excellent in appearance by using the heat-foamable emulsion composition of the present invention and can exhibit vibration damping properties when used for a vibration damping material is considered as follows. . Conventionally, for example, pigments such as calcium carbonate, thickeners, dispersing agents, foaming agents such as a heat-expandable capsule-type foaming agent are mixed in the coating material for vibration damping materials, and volatile components such as water in the emulsion by heat drying However, if a certain amount of the foaming agent is not added, the coating film is blistered. This is because, as described above, the evaporation path of the volatile components inside the coating film is blocked by forming the dry film by evaporating the volatile components from the coating surface before all the volatile components are evaporated from the inside of the coating film. This is considered to be because the dry film is lifted by the vapor of volatile components remaining inside the coating film. The foaming agent is thermally expanded to form an evaporation path for volatile components, thereby facilitating the escape of vapor and preventing blistering.
The heat-foamable emulsion composition of the present invention contains a specific emulsion polymer and a specific surfactant component, so that the coating film with good appearance is suppressed even if the heat-expandable capsule-type foaming agent is reduced or zero. Can be obtained. The reason for this is that the heat-foamable emulsion composition of the present invention contains the emulsion polymer and the surfactant component, thereby stabilizing the foam generated during heat-drying and maintaining its shape appropriately. This is presumably because the bubbles suitably form an evaporation path in the film on the surface of the coating film and maintain water drainage even under continued heating, so that a good coating film appearance can be obtained. Moreover, since the coating film obtained in this way has a porous structure, it can exhibit excellent vibration damping properties in a wide temperature range.

(Surfactant component)
The heat-foamable emulsion composition of the present invention contains a surfactant component, and the surfactant component has a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution thereof larger than a lamellar length at 20 ° C.
In the present specification, the lamella length refers to an index indicating how much the liquid film extends. A platinum ring (ring diameter: 14.54 mm, ring wire diameter: 0.40 mm) is immersed in a liquid and then pulled up in the vertical direction to maximize the stress caused by the liquid film formed between the ring and the liquid surface. The distance by which the ring is lifted until the liquid film breaks can be measured as the lamella length.
Detailed measurement conditions of the lamella length are as described later in the examples.
In addition, when the heat-foamable emulsion composition of the present invention contains two or more surfactant components, the surfactant component mixed at the same mass ratio as the surfactant component contained in the emulsion composition What is necessary is just to measure the lamella length in the 1.0 mass% aqueous solution about this mixture.

By using a surfactant component in which a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution of the surfactant component is larger than a lamellar length at 20 ° C., foaming during coating, The occurrence of coating film defects such as pinholes can be suppressed, and the generation of blisters during heat drying can be suppressed to obtain a coating film having a good appearance.

From the viewpoint of improving the appearance of the coating film, the surfactant component preferably has a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution of 1.5 cm or more, and is 1.7 cm or more. More preferably, it is 2.0 cm or more. In addition, the difference between the lamellar length at 55 ° C. and the lamellar length at 20 ° C. in the 1.0% by mass aqueous solution of the surfactant component is better as the effect becomes more remarkable. It is preferably 0.1 cm or more, more preferably 0.12 cm or more, and particularly preferably 0.20 cm or more.
In addition, among surfactant components, those having a high viscosity under high temperature conditions and those having generally good foam shape retention properties (for example, preferred among the surfactant components described later) are selected. The lamellar length at 55 ° C. in the 1.0 mass% aqueous solution and the difference between the lamellar length at 55 ° C. and the lamellar length at 20 ° C. can be suitably controlled.

The surfactant component means all agents that can function as a surfactant contained in the composition regardless of the purpose of use. That is, the surfactant component in the composition may have other functions as long as it can function as a surfactant. Examples of the purpose of use include the purpose of use as a dispersant, a wet penetrant, a foaming agent, and the like.

As the surfactant component, one or more of an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, and a polymer surfactant can be used. .
Examples of the anionic surfactant include fatty acid (salt), alkyl ether carboxylic acid (salt), N-acyl amino acid (salt), alkane sulfonic acid (salt), α-olefin sulfonic acid (salt), α-sulfo. Alkyl ester (salt), alkylbenzene sulfonic acid (salt), alkyl sulfosuccinic acid (salt), acyl isethionic acid (salt), N-acyl-N-alkyl taurine (salt), alkyl sulfate (salt), alkyl ether sulfate ( Salt), alkyl phosphoric acid ester (salt), polyoxyalkylene alkyl ether phosphoric acid ester (salt), alkyl diphenyl ether disulfonate, and the like, and one or more of them can be used. Of these, alkylsulfosuccinic acid (salt) is preferable.

As said anionic surfactant, 1 type (s) or 2 or more types of reactive surfactants, such as a sulfosuccinate type reactive anionic surfactant and an alkenyl succinate type reactive anionic surfactant, should be used. Can do.
Commercially available sulfosuccinate-type reactive anionic surfactants include Latemul S-120, S-120A, S-180 and S-180A (all trade names, manufactured by Kao Corporation), Eleminol JS-20 (Product) Name, manufactured by Sanyo Chemical Industries).
As a commercial item of an alkenyl succinate type reactive anionic surfactant, Latemul ASK (trade name, manufactured by Kao Corporation) and the like can be mentioned.
Furthermore, polyoxyethylene polycyclic phenyl ether sulfate (salt), polyoxyalkylene alkyl ether sulfate (salt), etc. can be used as an anionic surfactant as long as the lamellar length according to the present invention is satisfied. It is.

The nonionic surfactant is not particularly limited. For example, polyoxyethylene alkyl ether; polyoxyethylene alkyl aryl ether; sorbitan aliphatic ester; polyoxyethylene sorbitan aliphatic ester; aliphatic such as monolaurate of glycerol Monoglyceride; polyoxyethyleneoxypropylene copolymer; condensation products of ethylene oxide and aliphatic amines, amides or acids. For example, as a commercial product, Emulgen 1118S (manufactured by Kao Corporation) and the like can be mentioned. Also, allyloxymethylalkoxyethylhydroxypolyoxyethylene (for example, “ADEKA rear soap ER-20” manufactured by ADEKA), polyoxyalkylene alkenyl ether (for example, “Latemul PD-420”, “Latemul PD-” manufactured by Kao Corporation) Nonionic surfactants having reactivity such as “430” and the like can also be used. These 1 type (s) or 2 or more types can be used.

The cationic surfactant is not particularly limited, and examples thereof include dialkyldimethylammonium salts, ester-type dialkylammonium salts, amide-type dialkylammonium salts, dialkylimidazolinium salts, and the like. Can be used.

The amphoteric surfactant is not particularly limited, and examples thereof include alkyldimethylaminoacetic acid betaine, alkyldimethylamine oxide, alkylcarboxymethylhydroxyethylimidazolinium betaine, alkylamidopropylbetaine, alkylhydroxysulfobetaine, and the like. 1 type (s) or 2 or more types can be used.

The polymer surfactant is not particularly limited. For example, polyvinyl alcohol and a modified product thereof; (meth) acrylic water-soluble polymer; hydroxyethyl (meth) acrylic water-soluble polymer; hydroxypropyl (meth) acrylic Water-soluble polymers such as polyvinyl pyrrolidone, and one or more of them can be used.

The surfactant component may further have a substituent. Examples of the substituent include a hydrocarbon group, amino group, alkoxy group, alkylamino group, alkoxysulfonyl group, sulfoalkyl group, aminoalkyl group, carboxylic acid group, polyalkylene oxide chain-containing group, and alkenyloxy group. It is done.

The surfactant component is preferably a compound having no reactive carbon-carbon unsaturated bond from the viewpoint of improving the appearance of the coating film. When a compound that does not have a reactive carbon-carbon unsaturated bond is used as the surfactant component, the heat-foamable emulsion composition of the present invention has a surfactant (emulsion polymer) separately from the constituent units of the emulsion polymer. Other compounds). Thereby, the effect of the present invention for improving the appearance of the coating film can be exhibited more remarkably.

The said surfactant component can be obtained by making it react using a conventionally well-known method. Moreover, it is also possible to use a commercially available product as a surfactant component, or a product obtained by adding an aqueous solvent to a commercially available product and appropriately adjusting the solid content concentration.

In the heat-foamable emulsion composition of the present invention, the content of the surfactant component is preferably 0.1 to 20% by mass with respect to 100% by mass of all monomer components used as the raw material of the emulsion. From the viewpoint of exhibiting the effects of the present invention, the content of the surfactant component is more preferably 0.5% by mass or more, further preferably 1% by mass or more, and 2% by mass or more. It is more preferable that the content is 3% by mass or more. Further, the content of the surfactant component is more preferably 15% by mass or less, further preferably 10% by mass or less, further preferably 8% by mass or less, and 6% by mass or less. It is particularly preferred.

In addition, in this specification, all the monomer components used as the raw material of the emulsion are derived from the monomer unit used as the raw material of the emulsion as well as the monomer unit constituting the emulsion polymer in the heat-foamable emulsion composition of the present invention. The oligomers and monomers are not meant to be a surfactant component. The content of the component is a total amount of the surfactant (compound different from the emulsion polymer) and the structural unit derived from the compound in the emulsion polymer. In other words, the content of the component is the total amount of all the surfactants used in obtaining the heat-foamable emulsion composition of the present invention.

The content of the surfactant component in the heat-foamable emulsion composition of the present invention described above includes those that become the constituent units of the emulsion polymer by adding up the amounts of all the surfactants used as raw materials. Can be calculated. The content is the sum of the amount of the surfactant (a compound different from the emulsion polymer) in the heat-foamable emulsion composition of the present invention and the amount of the structural unit derived from the surfactant in the emulsion polymer. Can also be calculated.
In addition, the preferable content of the surfactant (a compound different from the emulsion polymer) in the heat-foamable emulsion composition of the present invention is within the range of the preferable content of the surfactant component described above. It is one of the preferable forms in the heat-foamable emulsion composition of the invention. In this preferred embodiment, a surfactant component may be included as a constituent unit of the emulsion polymer in addition to the surfactant in the heat-foamable emulsion composition of the present invention.
The content of the surfactant in the heat-foamable emulsion composition of the present invention can be determined by analyzing the components extracted from the heat-dried coating film using a high performance liquid chromatograph. Even when a surfactant having a reactive carbon-carbon unsaturated bond at the time of polymerization is used, it is possible to analyze those which are not constituent units of the emulsion polymer.

(Emulsion polymer obtained by polymerizing monomer components)
The heat-foamable emulsion composition of the present invention contains an emulsion polymer obtained by polymerizing monomer components. Especially, it is preferable that the heat-foamable emulsion composition of this invention contains the emulsion polymer formed by emulsion-polymerizing a monomer component.
The emulsion polymer has a storage elastic modulus of 5.0 × 10 ³ Pa or more at 70 ° C. and 1 Hz when dynamic viscoelasticity is measured. From the viewpoint of improving the appearance of the coating film and the vibration damping properties, the storage elastic modulus is preferably 1.0 × 10 ⁴ Pa or more, and preferably 1.6 × 10 ⁴ Pa or more. More preferably, it is more preferably 2.2 × 10 ⁴ Pa or more, and particularly preferably 4.0 × 10 ⁴ Pa or more from the viewpoint of excellent vibration damping. It is most preferable that it is x10 ⁴ Pa or more.

The emulsion polymer in the heat-foamable emulsion composition of the present invention preferably has a storage elastic modulus of 5.0 × 10 ⁵ Pa or less. The storage elastic modulus is more preferably 3.0 × 10 ⁵ Pa or less, further preferably 1.5 × 10 ⁵ Pa or less, and particularly preferably 5.0 × 10 ⁴ Pa or less. .
The storage elastic modulus is measured by the method described later in Examples.
In addition, the said storage elastic modulus can be controlled by adjusting the weight average molecular weight and composition of an emulsion polymer, and a glass transition temperature.

The emulsion polymer according to the present invention preferably has a weight average molecular weight of 30,000 to 500,000. When the emulsion polymer according to the present invention has such a weight average molecular weight, the storage elastic modulus is in a more appropriate range, the appearance of the resulting coating film is more excellent, and the emulsion polymer is used as a vibration damping material. In some cases, excellent vibration damping can be exhibited. The weight average molecular weight of the emulsion polymer according to the present invention is preferably 35,000 or more, more preferably 50,000 or more, and particularly preferably 90,000 or more, particularly from the viewpoint of further improving the appearance. is there. The weight average molecular weight is more preferably 420,000 or less, still more preferably 400,000 or less, still more preferably 270,000 or less, and particularly preferably 150,000 or less.
In addition, a weight average molecular weight (Mw) can be measured on the conditions as described in the Example mentioned later using GPC.

The emulsion polymer according to the present invention preferably has a glass transition temperature of -20 to 40 ° C. When an emulsion polymer having such a glass transition temperature is used as the emulsion polymer according to the present invention, the storage elastic modulus of the emulsion polymer at 70 ° C. and 1 Hz when dynamic viscoelasticity is measured may be moderate. it can. Moreover, when using a coating film as a damping material, the damping property in the practical temperature range of a coating film can be expressed effectively. The glass transition temperature of the emulsion polymer according to the present invention is more preferably −15 to 35 ° C., and further preferably −10 to 30 ° C.
The glass transition temperature (Tg) can be calculated by the method described in Examples described later. Further, when at least one of the emulsion polymers according to the present invention is obtained by multistage polymerization (for example, emulsion particles having a core part and a shell part), the glass transition temperature is all It means Tg (total Tg) calculated from the monomer composition used in the stage.

When at least one of the emulsion polymers according to the present invention is in a form in which two or more polymer chains are complexed, the glass transition temperature of one polymer chain (for example, the polymer chain of the core portion) is 0 to 60 ° C. Preferably there is. More preferably, it is 10-50 degreeC.
Moreover, it is preferable that the glass transition temperature of the other polymer chain (for example, polymer chain of a shell part) is -30-30 degreeC. More preferably, it is -20-20 degreeC.
Moreover, it is preferable that the difference of the glass transition temperature of one polymer chain and the other polymer chain is 5-60 degreeC. By providing a difference in the glass transition temperature in this manner, for example, when applied to a damping material application, it becomes possible to express a higher damping property under a wide temperature range, and is particularly in a practical range of 20 to Damping performance in the 60 ° C. region is further improved. The difference in glass transition temperature is more preferably 10 to 50 ° C, still more preferably 20 to 40 ° C.

As the emulsion polymer, various polymers that are miscible with a surfactant can be used. For example, it is one of the preferred embodiments in the present invention to include a polymer having a monomer unit having a carboxylic acid (salt) group. A carboxylic acid (salt) group means a carboxylic acid group and / or a carboxylic acid group.
The salt of the carboxylate group is preferably a metal salt, an ammonium salt, or an organic amine salt. 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 calcium and magnesium; trivalent metals such as aluminum and iron. Atoms are preferred. Moreover, as an organic amine which forms organic amine salt, alkanolamines, such as ethanolamine, diethanolamine, and triethanolamine, and a triethylamine are suitable.

The emulsion polymer preferably contains a (meth) acrylic polymer. The (meth) acrylic polymer refers to a polymer having a structural unit derived from a (meth) acrylic monomer. The (meth) acrylic monomer refers to a monomer having 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, or a derivative of such a monomer.

The (meth) acrylic polymer is preferably a (meth) acrylic acid polymer. The (meth) acrylic acid polymer refers to a polymer having a structural unit derived from a (meth) acrylic acid monomer. 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 the group is a carboxylic acid group (—COOH Group), a carboxylate group (—COOM group), or an acid anhydride group (—C (═O) —O—C (═O) — group). M represents a metal salt, an ammonium salt, or an organic amine salt. Examples of the metal atom forming the metal salt and the organic amine forming the organic amine salt include those mentioned above as the metal atom and organic amine forming the carboxylate salt. The (meth) acrylic acid monomer is preferably (meth) acrylic acid (salt).

The (meth) acrylic acid polymer may be composed only of a structural unit derived from a (meth) acrylic acid monomer, but a structural unit derived from a (meth) acrylic acid monomer, and other It is preferable that it comprises a structural unit derived from a copolymerizable unsaturated monomer. That is, it is preferable that the monomer component for obtaining the (meth) acrylic acid-based polymer comprises a (meth) acrylic acid-based monomer and other copolymerizable unsaturated monomers, The content ratio of the (meth) acrylic acid monomer described later and the content ratio of other copolymerizable unsaturated monomers are more preferable. By including the (meth) acrylic acid monomer, the dispersibility of the inorganic pigment and the like is improved in the paint containing the heat-foamable emulsion composition of the present invention, and the function of the resulting coating film is further improved. Moreover, it becomes easy to adjust the acid value of a polymer, a glass transition temperature, other physical properties, etc. by including the unsaturated monomer which can be copolymerized.

The (meth) acrylic acid polymer is, for example, a monomer composed of 0.1 to 5% by mass of a (meth) acrylic acid monomer and 95 to 99.9% by mass of other copolymerizable unsaturated monomers. It is preferable that it is obtained by copolymerizing the components. In the monomer component, the (meth) acrylic acid monomer is preferably 0.3% by mass or more, and the other copolymerizable unsaturated monomer is more preferably 99.7% by mass or less, and the (meth) acrylic acid monomer Is more preferably 0.5% by mass or more, and other copolymerizable unsaturated monomer is 99.5% by mass or less, (meth) acrylic acid monomer is 0.7% by mass or more, and other copolymers It is particularly preferred that the possible unsaturated monomers are 99.3% by weight or less. In the monomer component, the (meth) acrylic acid monomer is preferably 5% by mass or less, the other copolymerizable unsaturated monomer is preferably 95% by mass or more, and the (meth) acrylic acid monomer is 4% by mass. %, More preferably 96% by mass of other copolymerizable unsaturated monomers, 3% by mass or less of (meth) acrylic acid monomer, 97% by mass of other copolymerizable unsaturated monomers It is still more preferable that it is above. By setting it within such a range, the monomer component is stably copolymerized.

Other copolymerizable unsaturated monomers include (meth) acrylic monomers other than (meth) acrylic acid monomers; unsaturated monomers having aromatic rings; acrylonitrile, vinyl formate, vinyl acetate, vinyl propionate; And polyfunctional unsaturated monomers such as methylolpropane diallyl ether.
As the (meth) acrylic monomer other than the (meth) acrylic acid monomer, for example, 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 the monomer in which this group has a carboxylic acid ester group, or the derivative of such a monomer is mentioned.

Examples of (meth) acrylic monomers other than the above (meth) acrylic monomers include, for example, 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, Sooctyl 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, Reallyl cyanurate, ethylene glycol 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 .; esterified products of (meth) acrylic monomers other than these, and the like, and it is preferable to use one or more of these. .

As a monomer component used as a raw material for the (meth) acrylic acid polymer, a (meth) acrylic monomer other than the (meth) acrylic acid monomer is added to 100% by mass of all monomer components used as a raw material for the emulsion polymer. On the other hand, the content is preferably 20% by mass or more, more preferably 40% by mass or more, and still more preferably 60% by mass or more. Moreover, it is preferable to contain 99.9 mass% or less of (meth) acrylic-type monomers other than the said (meth) acrylic acid-type monomer with respect to 100 mass% of all the monomer components. It is more preferable.

Examples of the unsaturated monomer having an aromatic ring include divinylbenzene, styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, and the like, and preferably styrene.
That is, it is also one preferred embodiment of the present invention that the (meth) acrylic acid polymer is a styrene (meth) acrylic acid polymer obtained from a monomer component containing styrene. With such a configuration, the effects of the present invention can be sufficiently exhibited while reducing costs.

When the monomer component that is the raw material of the (meth) acrylic acid polymer includes the unsaturated monomer having an aromatic ring, the monomer component is 1% by mass or more with respect to 100% by mass of all monomer components used as the raw material of the emulsion. It is preferable to include 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and particularly preferably 40% by mass or more. The monomer component preferably contains the unsaturated monomer having an aromatic ring in an amount of 80% by mass or less, more preferably 70% by mass or less, and more preferably 60% by mass or less, based on 100% by mass of the total monomer components. It is more preferable to include. 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-acid type polymer.

The heat-foamable emulsion composition of the present invention contains an aqueous solvent, and the emulsion polymer is preferably dispersed in the aqueous solvent. In this specification, being dispersed in an aqueous solvent means being dispersed without being dissolved in an aqueous solvent. In this specification, the aqueous solvent may contain other organic solvents as long as it contains water, but is preferably water.

The heat-foamable emulsion composition of the present invention may contain one type of emulsion polymer obtained by polymerizing monomer components, or may contain two or more types. When the heat-foamable emulsion composition of the present invention contains two or more emulsion polymers according to the present invention, it may be a mixture obtained by mixing (blending) two or more emulsion polymers according to the present invention, It may be an emulsion polymer in which two or more kinds of polymer chains obtained by producing (for example, multistage polymerization) containing two or more kinds of polymer chains in a series of production steps are combined. In order to obtain one containing two or more emulsion polymers according to the present invention in a series of production steps, production conditions such as monomer dropping conditions may be appropriately set. Examples of the composite of the two or more polymer chains include a form having a core part and a shell part described later. The emulsion polymer according to the present invention has a core part and a shell part. For example, the emulsion polymer according to the present invention comprises two kinds of emulsion polymers according to the present invention, and the two kinds of emulsions according to the present invention. One in which one of the polymers forms a core and the other forms a shell. In addition, the said (meth) acrylic-type polymer is a polymer obtained using the monomer component containing a (meth) acrylic-acid type monomer, for example, a (meth) acrylic-acid type monomer forms the core part of an emulsion. It may be contained in either the monomer component or the monomer component forming the shell portion, or may be contained in both of them.

Further, at least one of the emulsion polymers forming the emulsion particles may be in the form of a composite of two or more polymer chains.

When the emulsion polymer is in a form in which two or more kinds of polymer chains are combined, one polymer chain and the other polymer chain may be completely compatible with each other and may have a homogeneous structure in which they cannot be distinguished. , They may not be completely compatible but may be formed inhomogeneously (for example, a core-shell composite structure or a microdomain structure). In order to draw out and produce a stable emulsion, for example, a core-shell composite structure is preferable.
An emulsion having a core-shell composite structure can exhibit excellent vibration damping properties over a wide range from room temperature to high temperature when used for vibration damping materials. 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 average particle diameter of the emulsion particles is preferably 80 to 450 nm.
By using emulsion particles having an average particle diameter in this range, the basic performance such as coating film appearance and coating properties can be made sufficient. It can be made better. 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 size is preferably 100 nm or more.
The average particle diameter of the emulsion particles can be measured by the method described in Examples described later.

It is preferable that the content rate of the said emulsion is 40-80 mass% with respect to the whole emulsion, and it is more preferable that it is 50-70 mass%.
In addition, solid content here means components other than solvents, such as an aqueous solvent contained in an emulsion.

Although it does not specifically limit as pH of the said emulsion, It is preferable that it is 2-10, It is more preferable that it is 3-9.5, It is still more preferable that it is 7-9. The pH of the emulsion can be adjusted by adding ammonia water, water-soluble amines, alkali hydroxide aqueous solution, or the like to the resin.
In this specification, pH can be measured by the method as described in the Example mentioned later.

The viscosity of the emulsion is not particularly limited, but is preferably 1 to 10000 mPa · s, more preferably 5 to 4000 mPa · s, still more preferably 10 to 2000 mPa · s, and 30 to 1000 mPa · s. It is more preferable that it is s, and it is especially preferable that it is 80-500 mPa * s.
In the present specification, the viscosity can be measured according to the conditions described in Examples described later.

Although the manufacturing method of the said emulsion polymer is not restrict | limited in particular, 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 emulsion polymer may be produced by a method other than emulsion polymerization, for example, by forming a emulsion by allowing a surfactant to act on a polymer polymerized by suspension polymerization.

The solid content of the emulsion according to the present invention is preferably 20% by mass or more and more preferably 30% by mass or more in 100% by mass of the solid content of the heat-foamable emulsion composition of the present invention. Preferably, it is more preferably 40% by mass or more, and particularly preferably 50% by mass or more. The content is preferably 99% by mass or less, more preferably 97% by mass or less, still more preferably 95% by mass or less, and particularly preferably 93% by mass or less. Most preferably, it is 91 mass% or less.
In addition, solid content means components other than solvents, such as an aqueous solvent.

The heat-foamable emulsion composition of the present invention may be an emulsion polymer obtained by emulsion polymerization using a monomer emulsion containing all of a surfactant and a monomer component as a raw material, and a part of the surfactant and the monomer component. It is also possible to obtain an emulsion polymer by emulsion polymerization using a monomer emulsion containing as a raw material, and then add the remainder of the surfactant to the obtained emulsion polymer. Thus, by emulsion polymerization using a monomer emulsion containing at least a part of a surfactant and a monomer component as a raw material, at least a part of the surfactant component is included as a surfactant that forms an emulsion. Become. In this case, at least a part of the surfactant component may be a normal surfactant (a compound separate from the polymer), a structural unit constituting a part of the polymer, and a surfactant. There may be.

The heat-foamable emulsion composition of the present invention may contain other components as long as it contains a surfactant component and an emulsion polymer.
When other components are included, the ratio of the other components to the entire heat-foamable emulsion composition of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less. The term “other components” as used herein means a non-volatile content (solid content) remaining in the coating film even after the heat-foamable emulsion composition of the present invention is applied and dried by heating. Volatile components are not included.

As described above, the heat-foamable emulsion composition of the present invention preferably contains a solvent such as an aqueous solvent.
The content of the solvent is preferably 3% by mass or more, more preferably 10% by mass or more, and more preferably 20% by mass or more in 100% by mass of the heat-foamable emulsion composition of the present invention. More preferably, it is particularly preferably 30% by mass or more. Further, the content of the solvent is preferably 97% by mass or less, more preferably 90% by mass or less, and still more preferably 80% by mass or less.

The heat-foamable emulsion composition of the present invention can be used to apply the coating itself to form a vibration-damping film, but is usually used to obtain the paint of the present invention described later.

The heat-foamable emulsion composition of the present invention is preferably used for a vibration damping material. In other words, the heat-foamable emulsion composition of the present invention is preferably a resin composition for vibration damping materials. The vibration damping material is preferably an automobile vibration damping material. In the present specification, the “resin composition for damping material” can be restated as “damping material”. In other words, the present invention is a vibration damping material containing an emulsion polymer, and the emulsion polymer has a storage elastic modulus of 5.0 × 10 ³ Pa at 70 ° C. and 1 Hz when dynamic viscoelasticity is measured. The damping material further contains a surfactant component, and the surfactant component has a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution thereof is larger than a lamellar length at 20 ° C. It is also a damping material.

<Coating material of the present invention>
The present invention is also a paint comprising the heat-foamable emulsion composition of the present invention and a pigment.
The preferable thing of the heat-foamable emulsion composition which the coating material of this invention contains is the same as the preferable thing of the heat-foamable emulsion composition of this invention mentioned above.
In the solid content of 100% by mass of the paint of the present invention, the solid content of the heat-foamable emulsion composition is preferably 1% by mass or more, more preferably 5% by mass or more, and more preferably 10% by mass or more. More preferably. The solid content of the heat-foamable emulsion composition is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less.

As the pigment, for example, one or more of an inorganic colorant, an organic colorant, a rust preventive pigment, a filler and the like can be used. Examples of the inorganic colorant include titanium oxide, carbon black, and a petiole. Examples of the organic colorant include dyes and natural pigments. Examples of the rust preventive pigment include a metal phosphate, a metal molybdate, and a metal borate. Examples of the filler include calcium carbonate, kaolin, silica, talc, barium sulfate, alumina, iron oxide, glass talk, magnesium carbonate, aluminum hydroxide, diatomaceous earth, clay, and other inorganic fillers; glass flakes, mica and other scaly forms Examples of inorganic fillers include fibrous inorganic fillers such as metal oxide whiskers, glass fibers, and wollastonite. Above all, the pigment is preferably an inorganic pigment.
The pigment preferably has an average particle diameter of 1 to 50 μm. The average particle diameter of the pigment 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.
As a compounding quantity of the said pigment, it is preferable to set it as 10-900 mass parts with respect to 100 mass parts of solid content of resin in the coating material of this invention, More preferably, it is 200-800 mass parts, More preferably, it is 300. It is -500 mass parts.

The paint of the present invention may further contain a dispersant.
Examples of the dispersant include inorganic dispersants such as sodium hexametaphosphate and sodium tripolyphosphate, and organic dispersants such as polycarboxylic acid-based dispersants.
As a compounding quantity of the said dispersing agent, 0.1-8 mass parts is preferable at solid content with respect to 100 mass parts of solid content of resin in the coating material of this invention, 0.5-6 mass parts is more preferable, 1 -3 mass parts is still more preferable.

The paint of the present invention may further contain a thickener.
Examples of the thickener include polyvinyl alcohol, cellulose derivatives, polycarboxylic acid resins, and the like.
As a compounding quantity of the said thickener, 0.01-5 mass parts is preferable by solid content with respect to 100 mass parts of solid content of the resin in the coating material of this invention, 0.1-4 mass parts is more preferable, 0.3-2 mass parts is still more preferable.

The paint of the present invention may further contain other components. As other components, for example, foaming agent; solvent; gelling agent; antifoaming agent; plasticizer; stabilizer; wetting agent; antiseptic agent; antifoaming agent; An inhibitor etc. are mentioned, These 1 type (s) or 2 or more types can be used.
The pigment, dispersant, thickener, and other components are, for example, a butterfly mixer, a planetary mixer, a spiral mixer, a kneader, a dissolver, etc. Can be mixed.

Examples of the solvent include water; and organic solvents such as ethylene glycol, butyl cellosolve, butyl carbitol, and butyl carbitol acetate. What is necessary is just to set suitably as a compounding quantity of a solvent, in order to adjust solid content concentration of the coating material of this invention.

By obtaining a coating film by using the coating material of the present invention, in particular, by heating and drying the coating material of the present invention to obtain a coating film, the coating material is foamed simultaneously with the drying of the coating material, thereby evaporating a solvent such as water. Can be formed. As a result, the swelling of the coating film can be suppressed, and a coating film having a good appearance can be obtained. Further, since the surfactant component functions as a foaming agent, it is possible to reduce the amount of an expensive foaming agent that has been conventionally used (for example, a heat-expandable capsule foaming agent). For example, the content of the heat-expandable capsule-type foaming agent is preferably 2% by mass or less, more preferably 1% by mass or less, with respect to 100% by mass of all monomer components used as the raw material for the emulsion polymer. Most preferably, it is 0 mass%.
Since the coating material of the present invention contains a specific emulsion polymer and a specific surfactant component, the content of the heat-expandable capsule-type foaming agent is set to 2% by mass or less, or the foaming agent is reduced. Can be sufficiently prevented from maintaining the shape of the coating film, and the appearance of the coating film can be further improved.

<The coating film of this invention and its manufacturing method>
The present invention is also a coating film obtained using the paint of the present invention.
The preferable thing of the coating material used in order to obtain the coating film of this invention is the same as that of the preferable thing of the coating material of this invention mentioned above.
The present invention is also a coating film obtained by foaming a paint containing an emulsion polymer obtained by polymerizing a monomer component, a surfactant component, and a pigment.
Below, the preferable form of the coating film of this invention is demonstrated.

The coating film of the present invention preferably has an average thickness of 2 to 8 mm. By setting it to 2 mm or more, the functions required for the coating film such as vibration damping can be more sufficiently exhibited. Moreover, by making it 8 mm or less, the heat drying property at the time of baking becomes more favorable, peeling of a coating film, generation | occurrence | production of a crack, etc. can be prevented, and a favorable coating film can be formed. The average thickness of the coating film is more preferably 6 mm or less, and still more preferably 5 mm or less.

The base material for forming the 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 and the like. Especially, forming a coating film on the surface of a steel plate is one of the preferable usage forms of the coating film of this invention.

The coating film of the present invention can be obtained, for example, by applying the coating composition of the present invention using a brush, spatula, air spray, airless spray, mortar gun, ricin gun or the like.

The present invention is a method for producing a coating film using a coating material, and the coating composition is obtained by heating the coating composition containing the heat-foamable emulsion composition of the present invention and a pigment to foam the coating material. It is also the manufacturing method of the coating film characterized by including a process. Here, the paint to be heated is a mixture of the emulsion polymer, the surfactant component, and the pigment, but the order of the combination is not particularly limited. The coating film of the present invention is preferably obtained by foaming the applied paint of the present invention by heating and drying. In order to foam the paint by heat-drying the paint, the surfactant component is usually not mechanically foamed by stirring the paint before heat-drying. In the heat drying step, it is preferable that the coating film formed by applying the coating material on the substrate is set to 40 to 200 ° C. More preferably, it is 90-180 degreeC, More preferably, it is 100-160 degreeC. You may perform preliminary drying at low temperature before a heat drying process.
Moreover, it is preferable that the time which makes a coating film the said temperature is 1 to 300 minutes. More preferably, it is 2 to 250 minutes, and particularly preferably 10 to 150 minutes.

The vibration damping property of the coating film of the present invention can be evaluated by measuring the loss factor of the film.
The loss factor is usually expressed by η and indicates how much the vibration applied to the coating film is attenuated. The above loss factor indicates that the higher the numerical value, the better the damping performance.
The loss factor can be measured by the method described in Examples described later.

The coating film of the present invention is excellent in appearance, can exhibit remarkable vibration damping properties in a wide temperature range when used as a vibration damping material, and is used for transportation vehicles such as automobiles, railway vehicles, ships, aircraft, and electrical equipment, It can be suitably used for building structures, construction equipment, and the like.

By using the heat-foamable emulsion composition of the present invention, it is possible to suitably obtain a coating film that is excellent in appearance and can exhibit vibration damping outstandingly in a wide temperature range when used as a vibration damping material.

Hereinafter, the present invention will be described in more detail with reference to modes for carrying out the invention, but the present invention is not limited only to the modes for carrying out these inventions. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

In the following examples and comparative examples, various parameters were evaluated as follows. The results are shown in Table 1.
<Storage modulus>
Dynamic viscoelasticity measurement was performed with a parallel plate having a diameter of 8 mm using a rheometer ARES-G2 manufactured by TA Instruments Japan. As measurement conditions, the frequency dependence (0.1-100 Hz) at 70 ° C. was measured, and the storage elastic modulus (G ′) at 1 Hz was determined.
<Lamellar length>
As a method for measuring the lamella length, a platinum ring having a ring wire diameter of 0.40 mm and a ring diameter of 14.54 mm is used, and a stage tension speed (DY-500 manufactured by Kyowa Interface Science Co., Ltd.) is used. Second, pre-wet stage vertical speed 1.0 mm / second, pre-wet immersion distance 2.50 mm, pre-wet immersion time 2 seconds, the lamella length of the liquid adjusted to a predetermined temperature and surfactant concentration in advance was measured.

In the following examples and comparative examples, various resin properties were evaluated as follows.
<Average particle size>
The average particle size of the emulsion particles was measured using a particle size distribution measuring device (Otsuka Electronics FPAR-1000) by a dynamic light scattering method.
<Nonvolatile content (N.V.)>
About 1 g of the obtained emulsion was weighed, and after 150 ° C. for 1 hour 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 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 a homopolymer (single polymer) composed of each monomer component.

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

The surfactant used in the following examples will be described.
The polyoxyethylene alkyl ether, sulfosuccinate, disodium salt has the following formula (i):

It is a compound represented by these. In the formula, n represents the average number of moles added. In the present specification, the compound of n = 8 is also represented as (i)-<1>.

The polyoxyethylene alkyl ether / sulfosuccinic acid half ester salt has the following formula (ii):

(Wherein R represents a secondary alkyl group having 12 to 14 carbon atoms).
In the formula, n represents the average number of moles added. In the present specification, a compound of n = 9 is also represented as (ii)-<1>.
N-alkylmonoamido disodium sulfosuccinate has the following formula (iii):

(Wherein R represents an alkyl group having 14 to 20 carbon atoms). In the present specification, this compound is also referred to as (iii).

The commercially available surfactants used in Examples and Comparative Examples will be described.
Neoperex G-65 (trade name, sodium dodecylbenzenesulfonate: manufactured by Kao Corporation)
New Coal 707SF (trade name, polyoxyethylene polycyclic phenyl ether / sulfate ester salt: manufactured by Nippon Emulsifier Co., Ltd.)
Lebenol WX (trade name, sodium polyoxyethylene alkyl ether sulfate: manufactured by Kao Corporation)

Example 1
280.7 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, 520 parts of methyl methacrylate, 160 parts of 2-ethylhexyl acrylate, 310 parts of butyl acrylate, 10.0 parts of acrylic acid, and t-dodecyl mercaptan (also referred to as t-DM) 2.0 as a polymerization chain transfer agent were added to the dropping funnel. Part, a monomer emulsion consisting of 180.0 parts of polyoxyethylene alkyl ether / sulfosuccinate / disodium salt (i)-<1> and deionized water previously adjusted to a 20% aqueous solution was charged. Next, while maintaining the internal temperature of the polymerization vessel at 75 ° C., 27.0 parts of the monomer emulsion, 5 parts of a 5% potassium persulfate aqueous solution as a polymerization initiator (oxidant), and 2% hydrogen sulfite 10 parts of an aqueous sodium solution was added to initiate initial polymerization. After 40 minutes, the remaining monomer emulsion was uniformly added dropwise over 210 minutes while maintaining the inside of the reaction system at 80 ° C. At the same time, 95 parts of a 5% aqueous potassium persulfate solution and 90 parts of a 2% aqueous sodium hydrogen sulfite solution were uniformly added dropwise over 210 minutes, and the temperature was maintained for 60 minutes after completion of the addition to complete the polymerization.
After cooling the resulting reaction solution to room temperature, 16.7 parts of 2-dimethylethanolamine and 39 parts of deionized water were added, the non-volatile content was 55.0%, the glass transition temperature was 3 ° C., the pH was 8.0, and the viscosity was 200 mPa · s. An acrylic emulsion (resin composition 1) having an average particle size of 230 nm and a weight average molecular weight of 102,000 was obtained.

(Example 2)
In the preparation of the monomer emulsion of Example 1, 520 parts of styrene was used instead of 520 parts of methyl methacrylate, the amount of 2-ethylhexyl acrylate was changed from 160 parts to 130 parts, and the amount of butyl acrylate was changed from 310 parts to 340 parts. The acrylic resin having the non-volatile content of 55.1%, the glass transition temperature of 3 ° C., the pH of 7.8, the viscosity of 250 mPa · s, the average particle size of 200 nm, and the weight average molecular weight of 95,000 was changed to An emulsion (resin composition 2) was obtained.

(Example 3)
In the preparation of the monomer emulsion of Example 1, polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i) previously adjusted to a 20% aqueous solution (i)-<1> in place of 180.0 parts in advance. Except for using adjusted polyoxyethylene alkyl ether / sulfosuccinic acid half ester salt (ii)-<1> 180.0 parts, the same operation as in Example 1 was carried out, the non-volatile content was 55.0%, and the glass transition temperature. An acrylic emulsion (resin composition 3) having a temperature of 3 ° C., a pH of 8.1, a viscosity of 300 mPa · s, an average particle diameter of 230 nm, and a weight average molecular weight of 103,000 was obtained.

Example 4
The same procedure as in Example 3 was performed except that the amount of t-DM was changed from 2.0 parts to 1.0 part in the preparation of the monomer emulsion of Example 3, and the non-volatile content was 55.0%, glass An acrylic emulsion (resin composition 4) having a transition temperature of 3 ° C., a pH of 8.1, a viscosity of 350 mPa · s, an average particle diameter of 210 nm, and a weight average molecular weight of 417,000 was obtained.

(Example 5)
The same procedure as in Example 3 was performed except that the amount of t-DM was changed from 2.0 parts to 5.0 parts in the preparation of the monomer emulsion of Example 3, and the nonvolatile content was 55.0%, glass An acrylic emulsion (resin composition 5) having a transition temperature of 3 ° C., a pH of 8.1, a viscosity of 250 mPa · s, an average particle diameter of 220 nm, and a weight average molecular weight of 42,000 was obtained.

(Example 6)
In the preparation of the monomer emulsion of Example 1, polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i) previously adjusted to a 20% aqueous solution (i)-<1> in place of 180.0 parts in advance. Adjusted polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i)-<1> 50.0 parts and polyoxyethylene alkyl ether, sulfosuccinic acid half ester salt (ii)-< Except for using 1> 130.0 parts, the same operation as in Example 1 was performed, the non-volatile content was 55.1%, the glass transition temperature was 3 ° C., the pH was 8.1, the viscosity was 300 mPa · s, the average particle size was 200 nm, and the weight An acrylic emulsion (resin composition 6) having an average molecular weight of 115000 was obtained.

(Example 7)
In the preparation of the monomer emulsion of Example 1, polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i) previously adjusted to a 20% aqueous solution (i)-<1> in place of 180.0 parts in advance. The same operation as in Example 1 was carried out except that 180.0 parts of adjusted N-alkylmonoamido disodium sulfosuccinate (iii) was used, and a non-volatile content of 54.5%, a glass transition temperature of 3 ° C., a pH of 8.0, An acrylic emulsion (resin composition 7) having a viscosity of 300 mPa · s, an average particle diameter of 210 nm, and a weight average molecular weight of 97000 was obtained.

(Example 8)
In the preparation of the monomer emulsion of Example 1, polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i) previously adjusted to a 20% aqueous solution (i)-<1> in place of 180.0 parts in advance. Adjusted polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i)-<1> 60.0 parts and Newcol 707SF (trade name, polyoxyethylene polycyclic phenyl ether / sulfuric acid prepared beforehand in 20% aqueous solution) (Ester salt: manufactured by Nippon Emulsifier Co., Ltd.) Except for using 120.0 parts, the same operation as in Example 1 was performed, the non-volatile content was 55.0%, the glass transition temperature was 3 ° C., the pH was 8.0, and the viscosity was 200 mPa · s. An acrylic emulsion (resin composition 8) having an average particle diameter of 250 nm and a weight average molecular weight of 103000 was obtained.

Example 9
In the preparation of the monomer emulsion of Example 1, in a dropping funnel, 515 parts of methyl methacrylate, 160 parts of 2-ethylhexyl acrylate, 310 parts of butyl acrylate, 10.0 parts of acrylic acid, 5 parts of acrylonitrile, 2.0 parts of t-DM, The same operation as in Example 1 except that 180.0 parts of polyoxyethylene alkyl ether / sulfosuccinic acid half ester salt (ii)-<1> and deionized water 183.0 parts previously adjusted to a 20% aqueous solution were charged. Then, an acrylic emulsion (resin composition 9) having a nonvolatile content of 55.3%, a glass transition temperature of 3 ° C., a pH of 8.2, a viscosity of 300 mPa · s, an average particle diameter of 190 nm, and a weight average molecular weight of 91000 was obtained.

(Example 10)
In the preparation of the monomer emulsion of Example 9, polyoxyethylene alkyl ether / sulfosuccinic acid half ester salt (ii) previously adjusted to a 20% aqueous solution (<1>) was adjusted to a 20% aqueous solution in advance instead of 180.0 parts. Except for using 180.0 parts of Neoperex G-65 (trade name, sodium dodecylbenzenesulfonate, Neoperex G-65 with a solid concentration of 65% diluted to a solid concentration of 20%: manufactured by Kao Corporation) The same operations as in Example 9 were carried out, and an acrylic emulsion (resin composition) having a non-volatile content of 55.0%, a glass transition temperature of 3 ° C., a pH of 8.1, a viscosity of 300 mPa · s, an average particle diameter of 190 nm, and a weight average molecular weight of 94,000. 10) was obtained.

(Comparative Example 1)
In the preparation of the monomer emulsion of Example 1, 260 parts of methyl methacrylate, 260 parts of styrene, 130 parts of 2-ethylhexyl acrylate, 340 parts of butyl acrylate, 10.0 parts of acrylic acid, 10.0 parts of t-DM, The same operation as in Example 1 except that 180.0 parts of polyoxyethylene alkyl ether / sulfosuccinic acid half ester salt (ii)-<1> and deionized water 183.0 parts previously adjusted to a 20% aqueous solution were charged. Then, an acrylic emulsion (resin composition 11) having a nonvolatile content of 55.0%, a glass transition temperature of 3 ° C., a pH of 8.0, a viscosity of 250 mPa · s, an average particle diameter of 210 nm, and a weight average molecular weight of 25000 was obtained.

(Comparative Example 2)
In the preparation of the monomer emulsion of Example 1, polyoxyethylene alkyl ether, sulfosuccinate, disodium salt (i) previously adjusted to a 20% aqueous solution (i)-<1> in place of 180.0 parts in advance. The same operation as in Example 1 was carried out except that 180.0 parts of adjusted rebenol WX (trade name, sodium polyoxyethylene alkyl ether sulfate: manufactured by Kao Corporation) was used. The nonvolatile content was 55.2%, and the glass transition temperature. An acrylic emulsion (resin composition 12) having a temperature of 3 ° C., a pH of 8.0, a viscosity of 300 mPa · s, an average particle diameter of 190 nm, and a weight average molecular weight of 101000 was obtained.

(Comparative Example 3)
The same procedure as in Example 10 was performed, except that the amount of t-DM was changed from 2.0 parts to 8.0 parts in the preparation of the monomer emulsion of Example 10, a nonvolatile content of 55.0%, glass An acrylic emulsion (resin composition 13) having a transition temperature of 3 ° C., a pH of 8.2, a viscosity of 250 mPa · s, an average particle diameter of 210 nm, and a weight average molecular weight of 36000 was obtained.

(Comparative Example 4)
In preparation of the monomer emulsion of Comparative Example 3, Neoperex G-65 (trade name, sodium dodecylbenzenesulfonate, neoperex G-65 having a solid concentration of 65%, which was previously adjusted to a 20% aqueous solution, had a solid content concentration of 20%. Except that 180.0 parts of polyoxyethylene alkyl ether sulfosuccinic acid half ester salt (ii)-<1> 180.0 parts previously adjusted to a 20% aqueous solution was used instead of 180.0 parts. The same operations as in Comparative Example 3 were carried out, and an acrylic emulsion (resin composition) having a non-volatile content of 54.9%, a glass transition temperature of 3 ° C., a pH of 8.1, a viscosity of 300 mPa · s, an average particle diameter of 200 nm, and a weight average molecular weight of 33,000. 14) was obtained.

<Preparation of paint>
The resin compositions 1 to 10 of Examples 1 to 10 and the resin compositions 11 to 14 of Comparative Examples 1 to 4 were blended as follows to prepare paints, and various characteristics were evaluated as follows. The results are shown in Table 1.
-Resin composition 1-14 350 parts-Calcium carbonate NN # 200 ^{* 1} 620 parts-Dispersant Aquaric DL-40S ^{* 2} 6 parts-Thickener Acreset WR-650 ^{* 3} 4 parts * 1: Nitto Powder Kogyo Co., Ltd. filler * 2: Nippon Shokubai Co., Ltd. polycarboxylic acid type dispersant (active ingredient 44%)
* 3: Nippon Shokubai Co., Ltd. Alkali-soluble acrylic thickener (active ingredient 30%)

Evaluation methods for various properties are shown below.
About the coating material obtained by the said Example and the comparative example, the external appearance evaluation of the coating film and the vibration damping test were implemented with the following method. The results are shown in Table 1.

<Appearance evaluation of coating film>
On the steel plate (trade name SPCC-SD, width 75 mm × length 150 mm × thickness 0.8 mm, manufactured by Nippon Test Panel Co., Ltd.), the prepared paint was applied so that the coating thickness was 3 mm. Then, it dried for 50 minutes at 150 degreeC using the hot air dryer, and evaluated the surface state of the obtained dry coating film on the following references | standards. In addition, foaming was generated from the paint by heating using a hot air dryer.
○: No abnormality.
O: Slight coating film blisters and cracks are observed in some places.
(Triangle | delta): The blister and crack of a coating film are seen in some places.
X: Swelling occurs throughout the coating film, peeling and cracks are observed.

<Vibration suppression test>
The above-mentioned paint was applied to a cold rolled steel sheet (trade name SPCC, width 15 mm × length 250 mm × thickness 1.5 mm, manufactured by Nippon Test Panel Co., Ltd.) with a thickness of 3 mm, pre-dried at 80 ° C. for 30 minutes, and then 150 Drying was carried out at a temperature of 30 ° C. for 30 minutes to form a damping material film having a surface density of 4.0 kg / m ² on the cold rolled steel sheet. In addition, foaming was generated from the paint by heating in the preliminary drying and the drying after the preliminary drying.
Measurement of vibration damping is performed by evaluating the loss factor at each temperature (20 ° C, 30 ° C, 40 ° C, 50 ° C, 60 ° C) using the cantilever method (loss factor measurement system manufactured by Ono Sokki Co., Ltd.). did. In addition, the evaluation of the vibration damping performance is performed based on the total loss factor (the sum of the loss factors at 20 ° C., 30 ° C., 40 ° C., 50 ° C., and 60 ° C.). It was supposed to be.

Considering together the working mechanism exerted by the configuration of the present invention described in the examples and comparative examples described above, 70 in the case of measuring dynamic viscoelasticity in a heat-foamable emulsion composition. An emulsion polymer having a storage elastic modulus of 5.0 × 10 ³ Pa or more at 1 ° C. at 1 ° C., and a surface activity that has a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution thereof larger than that at 20 ° C. It was found that by using the agent component, it is possible to suitably form a coating film having good heat drying property of the paint, excellent appearance, and exhibiting excellent vibration damping properties when used as a vibration damping material.

Claims (10)

A heat-foamable emulsion composition comprising an emulsion polymer,
The emulsion polymer has a storage elastic modulus at 70 ° C. and 1 Hz when dynamic viscoelasticity is measured of 5.0 × 10 ³ Pa or more,
The composition further comprises a surfactant component,
The surfactant component is a heat-foamable emulsion composition characterized in that a lamellar length at 55 ° C in a 1.0 mass% aqueous solution thereof is larger than a lamellar length at 20 ° C. 2. The heat-foamable emulsion composition according to claim 1, wherein the emulsion polymer has a storage elastic modulus of 5.0 × 10 ⁵ Pa or less. The heat-foamable emulsion composition according to claim 1, wherein the surfactant component has a lamellar length at 55 ° C. in a 1.0 mass% aqueous solution of 1.5 cm or more. The heat-foamable emulsion composition according to any one of claims 1 to 3, wherein the emulsion polymer includes a polymer having a monomer unit having a carboxylic acid (salt) group. The heat-foamable emulsion composition according to any one of claims 1 to 4, wherein the emulsion polymer contains a (meth) acrylic polymer. The heat-foamable emulsion composition according to claim 1, wherein the composition is used for a vibration damping material. The heat-foamable emulsion composition according to claim 6, wherein the vibration damping material is an automobile vibration damping material. A paint comprising the heat-foamable emulsion composition according to any one of claims 1 to 7 and a pigment. A coating film obtained by using the paint according to claim 8. A method of producing a coating film using a paint,
Heat-foamable emulsion composition according to any one of claims 1 to 7, and a paint film comprising a step of foaming the paint to obtain a paint film by heating the paint containing the pigment. Manufacturing method.