JP6247347B2 - Damping emulsion and damping composition - Google Patents

Description

The present invention relates to a damping material emulsion and a damping material composition. More specifically, the present invention relates to an emulsion for damping material and a damping material composition useful as a damping material used to prevent vibration and noise in various structures and maintain quietness.

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. If the shape of the sound generation location is complicated, it is difficult to apply these molded products to the vibration generation location. Various methods have been studied. For example, an asphalt sheet containing an inorganic powder has been used under the floor of an automobile, but it has been desired to improve workability and the like because it has to be heat-sealed.

Accordingly, coating type damping materials (paints) have been developed as an alternative material for such molded products. For example, a coating formed by spraying or spraying on a corresponding portion by any method. Various vibration-damping paints that can obtain a vibration absorption effect and a sound absorption effect by using a film have been proposed. Specifically, for example, as a water-based vibration-damping paint with improved coating film hardness obtained by blending a synthetic resin powder with a color developing agent such as asphalt, rubber, synthetic resin, and the like suitable for indoor use in automobiles, Anti-vibration coatings in which activated carbon is dispersed as a filler in a resin emulsion have been developed.

As an emulsion for a vibration damping material, for example, an aqueous polymer dispersion containing two or more polymers having different glass transition temperatures, the aqueous polymer dispersion has at least a specific structure. An emulsion for an aqueous vibration damping material comprising a polymer having a low glass transition temperature and a polymer having a specific structure and a high glass transition temperature is disclosed (for example, see Patent Document 1). Moreover, it is a copolymer emulsion for a vibration damping material obtained by copolymerizing a monomer mixture that essentially contains an acrylic monomer, and contains 25% by mass or more of methyl methacrylate with respect to the monomer mixture. A copolymer emulsion is disclosed (for example, see Patent Document 2). Such conventional emulsions for vibration damping materials were intended to give high vibration damping properties in a wide temperature range, but are more suitable as materials used for vibration damping materials of various structures. Therefore, it has been required to have a higher level of vibration control.

Furthermore, the vibration-damping water-based coating composition is a vibration-damping water-based coating composition comprising a resin emulsion and a filler as essential components, and the resin emulsion has a Tg of 10 to 50 ° C. A vibration-damping water-based paint having a loss angle tangent (tan δ) of 1.5 or more and an average particle diameter of resin particles of 150 to 1000 nm, wherein the filler comprises 1 to 45% by weight of activated carbon. In a vibration-damping aqueous coating composition comprising a composition (for example, see Patent Document 3), a vinyl acetate resin emulsion and a filler as essential components, the vinyl acetate resin has a Tg of 10 to 50 ° C. There is disclosed a vibration-damping water-based coating composition (see, for example, Patent Document 4) having a gel fraction measured with a methanol solvent of 0 to 30% and a loss angle tangent (tan δ) of 1.5 or more. ing However, when it is a vibration damping composition containing such a composition and other raw materials, sufficient properties are not obtained in the dispersibility and heat drying properties of other raw materials, and various structures There was room for improvement as an emulsion for a vibration damping material that can be suitably used for a body or the like.

JP 2005-281576 A (page 1-2) Japanese Patent Laying-Open No. 2005-28177 (page 1-2) JP-A-10-324822 (page 1-2) JP-A-10-204370 (page 1-2)

The present invention has been made in view of the above-described present situation, and an object thereof is to provide an emulsion for a vibration damping material and a vibration damping material composition capable of forming a vibration damping material excellent in vibration damping performance at a higher level. It is what.

The inventor conducted various studies on methods for producing a vibration damping material having excellent vibration damping properties using an emulsion for vibration damping materials composed of a polymer obtained by polymerizing monomer components. The present inventors have found that there is a correlation with the vibration damping properties of the film formed using the emulsion. That is, it has been found that by designing the polymer density so as to be a certain value or higher, an emulsion that exhibits outstanding vibration damping properties can be obtained in the vibration damping material. Such knowledge is not recognized in the prior art at all, and is a new knowledge discovered by the present inventor, and the fact that it has been found that the polymer density greatly affects the vibration damping performance itself has important technical significance. It can be said that there is. The polymer density can be obtained by calculation, and by setting this to 1.11 g / cm ³ or more, the loss of dynamic viscoelasticity of the film formed from the emulsion for damping material, which becomes an index of damping properties The loss factor of the damping material composition including the tangent (tan δ) and the damping material emulsion can be made higher than ever. In addition, by controlling the weight average molecular weight of the polymer and using a polymer synthesized mainly with an acrylic monomer, the heat drying property and dispersibility of other raw materials contained in the vibration damping composition are increased. It was found that a better damping material can be obtained. And the damping material formed using such emulsion for damping materials can be used suitably with respect to various structures which require damping properties, and can solve the above-mentioned problem wonderfully. The present invention has been conceived and reached the present invention.
In addition, this invention provides the new polymer design method of enabling the polymer design of the emulsion for damping materials by calculation of a polymer density. It can be said that it has unprecedented efficiency and usefulness as a technique capable of simulating polymer design.

That is, the present invention is an emulsion for vibration damping materials composed of a polymer obtained by polymerizing monomer components, and the emulsion for vibration damping materials having a polymer density of 1.11 g / cm ³ or more.
The present invention is also a vibration damping composition containing the above damping material emulsion, pigment, foaming agent and thickener as essential components.
The present invention is described in detail below.

The emulsion for vibration damping materials of the present invention is composed of a polymer obtained by polymerizing monomer components. The emulsion for vibration damping materials usually contains a polymer and a medium, and the polymer exists in a form dispersed in the form of particles in the medium. The medium is not particularly limited as long as the polymer is not dissolved in the medium and can be dispersed in the medium. Examples of such a medium include water, aqueous solvents such as one or two or more kinds of solvents that can be mixed with water, and mixed solvents in which water is the main component. Medium. Among these, water is preferable in consideration of safety and environmental impact when applying the paint containing the emulsion for vibration damping material of the present invention.

The polymer may be a homopolymer (homopolymer) obtained by polymerizing one kind of monomer, or a copolymer (copolymer) obtained by polymerizing two or more kinds of monomers. There is no particular limitation. Moreover, the emulsion for vibration damping materials may be composed of a single type of polymer, or may be composed of a plurality of types of polymers. For example, it may include two types of polymers, a homopolymer and a copolymer, or may include three or more types of polymers. The combination of contained polymers is not particularly limited, and is preferably determined as appropriate according to the use of the damping material.

The content of the nonvolatile component in the emulsion for damping material, that is, the polymer content obtained by polymerizing the monomer component, is preferably 30 to 70% by mass with respect to 100% by mass of the total amount of emulsion for damping material. It is. If it exceeds 70% by mass, the viscosity of the emulsion for vibration damping materials becomes too high, and sufficient dispersion stability cannot be maintained, which may cause aggregation. If it is less than 30% by mass, sufficient vibration damping properties may not be exhibited. More preferably, it is 40-65 mass%.

The polymer has a polymer density of 1.11 g / cm ³ or more. The higher the polymer density, the better the damping performance. This is because the polymer chains are tightly packed, and the friction between the polymer chains is likely to occur, and vibration energy is converted into thermal energy. This is probably because the conversion efficiency has improved. The polymer density should just be 1.11 g / cm < ³ > or more as the whole polymer contained in the emulsion for vibration damping materials. That is, the average of the polymer density contained in the emulsion for damping material may be 1.11 g / cm ³ or more, and in the emulsion for damping material of the present invention, the polymer density is less than 1.11 g / cm ^3. The polymer may be included. The polymer density is more preferably 1.13 g / cm ³ or more, still more preferably 1.19 g / cm ³ or more, and particularly preferably 1.22 g / cm ³ or more.

In the present invention, the “polymer density” can be calculated from a monomer for producing a polymer, and a monomer composition constituting the polymer can be designed based on the calculation. The polymer density can be calculated by using Synthia Modules Materials Studio ^R Ver4.3 (Cynthia Module Material Studio version 4.3) manufactured by Accelrys Corporation. First, a monomer structure is created from Visualizer Materials Studio ^R Ver4.3 (Visualizer Material Studio version 4.3) manufactured by Accelrys Co., Ltd. using 3-D Sketcher (sketcher), and a repeating structure is defined. Using the defined monomer structure, polymer properties (polymer density, etc.) are calculated with the Synthia module. The polymer density is preferably calculated at a temperature of 298K and a molecular weight of 100,000. The Synthia module is a software that can calculate the physical properties of polymers by using quantitative structure property relationship (QSPR). The physical properties of polymers can be calculated from the monomer structure using the connectivity index obtained from graph theory. Can be calculated. Detailed theory is described in the following literature.
Title: “Prediction of Polymer Properties, Third Edition”
Author: Josef Bicerano
Publisher: Marcel Dekker Ink. , New York
ISBN: 978 0824 708214
Copyright: 2002

The polymer density can be calculated using the above-mentioned Synthia module, whether it is a homopolymer (homopolymer) or a copolymer (copolymer). In addition, when an emulsion for vibration damping materials is actually produced by synthesizing a copolymer, a plurality of particulate polymers are usually formed. These particulate polymers are derived from raw material monomers respectively. The proportion of structures to be made may be different. Therefore, the proportion (mass fraction) occupied by the monomer structure in the copolymer is preferably determined from the proportion of the monomer component when the polymer is synthesized.

When the emulsion for vibration damping materials contains a plurality of types of polymers, the total density of the plurality of types of polymers can be determined by the volume fraction from the total amount of all the polymers. For example, assuming that the total amount of the polymer in the emulsion for vibration damping materials is 100% by mass, the polymer X having a polymer density X contains a mass%, and the polymer Y having a polymer density Y contains b% by mass (a + b = 100), the total polymer density Z = (a + b) / (a / X + b / Y), that is, (total weight of polymer) / (total volume of polymer). The same method can be used when three or more kinds of polymers are used. In the case where a plurality of types of polymers are included in the vibration damping emulsion, the polymer density in the vibration damping emulsion may be 1.11 g / cm ³ or more as a whole. The form may include a polymer having a polymer density of 1.11 g / cm ³ or more and a polymer having a polymer density of less than 1.11 g / cm ³ .

The polymer has a polymer density of 1.11 g / cm ³ or more. According to this, the polymer has a damping performance that is superior to that produced from a conventional emulsion for damping materials. A vibration material can be formed. For example, the vibration damping property can be evaluated by a loss tangent in dynamic viscoelasticity measurement. By setting the polymer density to 1.11 g / cm ³ or more, the loss of the film formed from this emulsion for vibration damping materials The peak value of the tangent can be made as excellent as 2.5 or more. That is, the film formed from the above damping material emulsion preferably has a loss tangent (peak value) of 2.5 or more in dynamic viscoelasticity measurement. The loss tangent is more preferably 2.6 or more, further preferably 2.7 or more, particularly preferably 2.8 or more, and most preferably 2.9 or more.

The loss tangent is usually expressed as tan δ, obtained by dynamic viscoelasticity measurement, and a value obtained by dividing the loss elastic modulus by the storage elastic modulus. The value of tan δ increases as the rate of loss of the elastic modulus increases. Since loss of the elastic modulus means vibration damping, the greater the value of tan δ, the better the vibration damping performance.
The loss tangent can be measured by using a film as a sample and using a dynamic viscoelasticity measuring apparatus (model: RSA III, manufactured by TA Instruments). The measurement conditions are preferably measured under the following conditions.
Measurement mode: Pull mode Measurement frequency: 1 Hz
Temperature increase rate: 3 ° C./min.
Elongation rate: 0.1%
Measurement temperature: -40 to 80 ° C
The film is produced by casting the emulsion for vibration damping material of the present invention on a form glass plate so that the dry film thickness is 0.1 mm, drying at 95 ° C. for 30 minutes, and then drying at 130 ° C. for 30 minutes. It can be obtained by peeling from the glass plate. As a dimension of a film, what was produced in the magnitude | size of 25 mm (length) x 5 mm (width) x 0.1 mm (thickness) can be used.

The polymer is preferably formed by polymerizing a monomer component containing a monomer having a homopolymer density of 1.15 g / cm ³ or more at 20% by mass or more with respect to 100% by mass of all monomer components. By using such a polymer, it is possible to form a film having better vibration damping properties, and it can be particularly suitably used for applications that require excellent vibration damping properties. More preferably, it is a monomer component containing 30% by mass or more of a monomer having a homopolymer density of 1.15 g / cm ³ or more, more preferably 40% by mass or more.

The glass transition temperature (Tg) of the polymer, that is, the glass transition temperature of the polymer obtained by polymerizing the monomer component, is preferably -20 to 40 ° C. By being in such a range, it becomes possible to express higher vibration damping properties under a wide temperature range in the practical temperature range. More preferably, it is -15-35 degreeC, More preferably, it is -10-30 degreeC.
The Tg of the polymer may vary greatly when measured by various thermal analysis methods. Therefore, in the present case, in the case of a homopolymer, a polymer handbook (J. Brandrup (J. Brandrup) is used. ), Etc., Polymer Handbook, 3rd edition, New York, John Wiley & Sons, Inc. (1989, IV209-IV258). Moreover, Tg (K) of a copolymer (copolymer) is calculated | required by the theoretical formula shown by following formula (1) using Tg of the said homopolymer.

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

When two or more polymers are used as the polymer, it is preferable to use ones having different Tg. Thus, by providing a difference in glass transition temperature (Tg), it becomes possible to express higher vibration damping properties under a wide temperature range. When three or more kinds of polymers are used, it is sufficient that at least two of these polymers have different Tg, and the remaining one or more kinds have the same Tg as one of the two kinds of polymers. It may be a thing.

As the polymer having a different Tg, a polymer having a high Tg is referred to as “polymer (A)”, and a polymer having a low Tg is referred to as “polymer (B)”. If the difference is less than 10 ° C, the vibration damping property may not be sufficiently exhibited in a practical temperature range, for example, in the range of 20 to 60 ° C. More preferably, it is 12 degreeC or more as a difference of Tg, More preferably, it is 14 degreeC or more. Moreover, even if the temperature difference is too large, there is a possibility that the vibration damping property in the practical temperature range may not be sufficient, so that the difference in Tg is preferably 100 ° C. or less. More preferably, it is 90 degrees C or less, More preferably, it is 80 degrees C or less.

Specifically, the glass transition temperature (TgA) of the polymer (A) is preferably 0 ° C. or higher. As a result, the drying property of the damping material coating formed using the paint (damping material composition) containing the emulsion for damping material of the present invention is improved, and the expansion and cracks of the coating surface are sufficiently suppressed. Will be. That is, a vibration damping material having extremely excellent vibration damping properties is formed. The glass transition temperature (TgA) of the polymer (A) is more preferably 5 ° C. or higher. Moreover, as glass transition temperature (TgB) of the said polymer (B), -50 degreeC or more and 10 degrees C or less are preferable. More preferably, it is −20 ° C. or higher and 0 ° C. or lower.

The polymer preferably has a weight average molecular weight of 20,000 to 400,000. If it is less than 20,000, there is a possibility that the coating film swells when a vibration damping composition containing an emulsion for vibration damping material is applied and dried by heating, and sufficient heat drying property may not be obtained. is there. If it exceeds 400,000, there is a risk that the coating film will be cracked or peeled off from the base material when drying by heating, and sufficient film-forming property may not be obtained. If the weight average molecular weight is too large, sufficient vibration damping properties may not be obtained. Moreover, there is a possibility that a sufficient balance of damping properties cannot be maintained. More preferably, it is 30000-300000 as a weight average molecular weight, More preferably, it is 35000-250,000, Most preferably, it is 40000-200000.
The weight average molecular weight can be determined, for example, 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.

As described above, by setting the glass transition temperature and the weight average molecular weight of the polymer to a more preferable range, it is possible to achieve sufficient vibration damping properties in a wider temperature range, and when used for various structures. It can be particularly preferably used. As a preferable polymer form, the glass transition temperature is −20 to 40 ° C. and the weight average molecular weight is 20000 to 400000.

The monomer component for forming the polymer is not particularly limited as long as it is a polymerizable monomer capable of setting the polymer density of the emulsion for damping material to 1.11 g / cm ³ or more. For example, when the emulsion for vibration damping materials contains a plurality of types of polymers, the polymerizable monomer to be used is selected so that the polymer density of at least one type of polymer is 1.11 g / cm ³ or more. The polymer density should be 1.11 g / cm ³ or more on average. For example, (meth) acrylic monomers and other polymerizable monomers copolymerizable with (meth) acrylic monomers described later (for example, ethylenically unsaturated monomers copolymerizable with (meth) acrylic monomers) are used. be able to. These monomers can be used alone or in combination of two or more.
Examples of polymers obtained by polymerizing such monomer components include acrylic resins, urethane resins, SBR resins, epoxy resins, vinyl acetate resins, vinyl acetate-acrylic resins, vinyl chloride resins, vinyl chloride-acrylic resins. Resin, vinyl chloride-ethylene-based resin, vinylidene chloride-based resin, styrene-butadiene-based resin, acrylonitrile-butadiene-based resin, polyester resin, etc. may be used, and the polymer density of the polymer in the emulsion for vibration damping materials as a whole is 1.11 g / If it is cm ³ or more, the effect of the present invention will be sufficiently exerted.

As a monomer component for forming the said polymer, the form containing a (meth) acrylic-type monomer and the other copolymerizable ethylenically unsaturated monomer may be sufficient, for example. By including a (meth) acrylic monomer and another copolymerizable ethylenically unsaturated monomer, it becomes easy to adjust the acid value, Tg, physical properties and the like of the emulsion. Also, by using a (meth) acrylic monomer, as will be described later, improvement in dispersibility of pigments, foaming agents, thickeners, etc., improvement in vibration damping properties, etc. In addition, the storage stability can be improved.
The content ratio of the above (meth) acrylic monomer and other copolymerizable ethylenically unsaturated monomer is 10 to 100% by mass of (meth) acrylic monomer with respect to 100% by mass of all monomer components, and others. It is preferable that 0-90 mass% of the copolymerizable ethylenically unsaturated monomer is included. In the said monomer component, when a (meth) acrylic-type monomer is less than 10 mass%, there exists a possibility that an emulsion cannot be copolymerized stably. In the emulsion according to the present invention, the synergistic effect of the monomer units formed from these monomers makes it possible to more fully exhibit excellent heat drying properties and vibration damping properties in the aqueous vibration damping material. More preferably, it comprises 20 to 100% by mass of (meth) acrylic monomer and 0 to 80% by mass of other copolymerizable ethylenically unsaturated monomer with respect to 100% by mass of all monomer components.
Other copolymerizable ethylenically unsaturated monomers include monomers other than (meth) acrylic monomers that can be copolymerized with (meth) acrylic monomers.

The polymer is preferably polymerized mainly with a (meth) acrylic monomer. As the above polymer is a (meth) acrylic polymer obtained by polymerizing a (meth) acrylic monomer as a main component, it is included in the vibration damping composition requiring the damping material emulsion of the present invention as necessary. Dispersibility of pigments, foaming agents, thickeners and the like is improved, and vibration damping properties are further improved. In addition, when a vibration damping composition is produced using the emulsion for vibration damping materials, it is also preferable from the viewpoint of good storage stability. For example, when a polymer mainly composed of vinyl acetate is used, when it is used as a vibration damping composition (paint), the storage stability may be deteriorated due to the aggregation of the polymer. In the case of polymerized mainly with a meth) acrylic monomer, excellent storage stability can be obtained.
In addition, in the case of polymerizing mainly a (meth) acrylic monomer, in the production of the vibration damping emulsion of the present invention, 50% by mass or more of (meth) acrylic based on 100% by mass of all monomer components to be polymerized. It is preferable to polymerize a monomer component containing a monomer. More preferably, it is 55 mass% or more as content of a (meth) acrylic-type monomer, More preferably, it is 60 mass% or more.
The (meth) acrylic monomer means a monomer having a (meth) acryloyl group, and the (meth) acryloyl group may have a substituent. For example, (meth) acrylic acid, (meth) acrylic acid ester, metal salt of (meth) acrylic acid, etc. may be used. In addition, the (meth) acryloyl group may have a substituent, and crotonic acid, citraconic acid, itaconic acid, maleic acid, fumaric acid and the like are also included in the monomer having a (meth) acryloyl group. Two or more kinds may be used.

The (meth) acrylic polymer may be a homopolymer or a copolymer, and is not particularly limited. However, from the viewpoint of having excellent vibration damping properties in a wide temperature range, the acrylic copolymer It is preferable that That is, the polymer is preferably copolymerized mainly with a (meth) acrylic monomer. The (meth) acrylic copolymer is a copolymer obtained using at least one (meth) acrylic monomer and, if necessary, another polymerizable monomer. That is, it means that at least one of the above monomers is an acrylic monomer having a (meth) acryloyl group. In addition, when using 2 or more types of acrylic polymers, these are various physical properties, such as a weight average molecular weight, a glass transition temperature, SP value (solubility coefficient), the kind of monomer used, the usage rate of a monomer, etc., for example. Any one of them may be different.

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, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,4-butane Dioldiak 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, allyl acrylate, allyl methacrylate, 2-chloroethyl (meth) In addition to acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, and the like, it is preferable to use one or more of these salts and esterified products. From the viewpoint of high polymer density of the homopolymer, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylic acid and the like are preferable. More preferred are methyl acrylate and ethyl acrylate.

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 suitable, and the organic amine salt is preferably an alkanolamine salt such as an ethanolamine salt, diethanolamine salt, or triethanolamine salt, or a triethylamine salt.

As said monomer component, the other polymerizable monomer copolymerizable with a (meth) acrylic-type monomer may be included. Examples of other polymerizable monomers include vinyl monomers having no aromatic ring such as vinyl formate, vinyl acetate, vinyl propionate, vinyl chloride, and vinyl fluoride; styrene, divinylbenzene, α-methylstyrene, vinyltoluene, Vinyl monomers having an aromatic ring such as ethyl vinyl benzene, chloromethyl styrene and fluoromethyl styrene; vinyl monomers such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, diacetone acrylamide, N-methylol acrylamide, N- Examples thereof include polymerizable monomers having a nitrogen atom and an unsaturated bond such as methylol methacrylamide.

Among the other copolymerizable ethylenically unsaturated monomers, nitrogen atoms and unsaturated bonds such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, diacetone acrylamide, N-methylol acrylamide, N-methylol methacrylamide, etc. The polymerizable monomer has preferably 40% by mass or less with respect to 100% by mass of all monomer components. More preferably, it is 20 mass% or less.

The polymer is preferably obtained by emulsion polymerization of a monomer component. According to this, since the polymer can be uniformly dispersed in the medium, the uniformity in the emulsion for vibration damping materials is improved, and more stable characteristics can be obtained.
The emulsion for vibration damping material of the present invention is 1.0 part by weight or more of anionic property with respect to 100 parts by weight of the total amount of monomer components used in the production of a polymer obtained by emulsion polymerization of monomer components using an anionic emulsifier. It is preferable that it is polymerized containing an emulsifier. If it is less than 1.0 part by weight, there is a possibility that excellent drying properties and vibration damping properties cannot be exhibited. Moreover, there is a possibility that the pigment miscibility when mixed with the pigment may not be sufficient, and there is a possibility that it cannot be used as a damping material for various structures. Preferably it is 2.0 weight part or more, More preferably, it is 2.5 weight part or more. In consideration of economy, it is preferably 5.0 parts by weight or less.

The emulsion for vibration damping material is preferably an aqueous emulsion in which water is a continuous phase and a polymer obtained by polymerizing monomer components in the presence of the anionic emulsifier is dispersed. Usually, a damping material is applied by applying a damping material composition comprising such an emulsion for damping materials which essentially requires such a polymer (emulsion particles) and, if necessary, other additives and solvents. Will be formed. Hereinafter, the particulate polymer is also referred to as an emulsion particle.

From the above, it is preferable to include a step of polymerizing the monomer component by emulsion polymerization in the presence of an anionic emulsifier as the method for producing the emulsion for vibration damping materials. The form for carrying out the emulsion polymerization is not particularly limited, and for example, the polymerization can be carried out by appropriately adding a monomer component, a polymerization initiator and an anionic emulsifier in an aqueous medium. Moreover, it is preferable to use a polymerization chain transfer agent or the like for molecular weight adjustment. By carrying out polymerization by adding a polymerization chain transfer agent, the weight average molecular weight can be controlled. For example, when a polymerization chain transfer agent is not used in the conventional method for producing an emulsion for vibration damping materials, the possibility that the weight average molecular weight is 100,000 or less is extremely low, the weight average molecular weight is large, and sufficient film formation is achieved. However, the weight average molecular weight can be controlled (for example, 100,000 or less) by using a polymerization chain transfer agent. That is, a form in which the polymer is polymerized using a polymerization chain transfer agent and a weight average molecular weight is 100,000 or less is also a preferred form of the present invention. In addition, although the case where emulsion polymerization was performed was described here, using a polymerization chain transfer agent can also be applied to the case where polymerization of a polymer is not performed by emulsion polymerization.
As the anionic emulsifier, those described later can be used. Further, other emulsifiers can be used together with the anionic emulsifier when carrying out the emulsion polymerization. As other emulsifiers, one or more of nonionic surfactants, cationic surfactants, amphoteric surfactants, polymer surfactants and the like can be used.

The emulsion for vibration damping material of the present invention may be a mixture (blend) of emulsion particles obtained by emulsion polymerization of monomer components using an anionic emulsifier and other emulsion particles. In this case, the mass ratio of emulsion particles formed by emulsion polymerization of monomer components using an anionic emulsifier and other emulsion particles (emulsion particles formed by emulsion polymerization of monomer components using an anionic emulsifier / other emulsion particles) ) Is preferably set to 100 to 50/0 to 50.

The anionic emulsifier is a sulfate compound or a succinate compound, and the sulfate compound includes an aliphatic alkyl group having 8 or more carbon atoms, an oleyl group, an alkylphenyl group, a styryl group, and a benzyl group. It is preferable to have at least one group selected from the group consisting of: As the aliphatic alkyl group having 8 or more carbon atoms, those having 12 or more carbon atoms or one or more aromatic rings are more preferable.

The anionic emulsifier is not particularly limited, and examples thereof include polyoxyalkylene alkyl ether sulfate, polyoxyalkylene oleyl ether sulfate sodium salt, polyoxyalkylene alkylphenyl ether sulfate, alkyl diphenyl ether disulfonate, poly Oxyalkylene (mono, di, tri) styryl phenyl ether sulfate, polyoxyalkylene (mono, di, tri) benzyl phenyl ether sulfate, alkenyl succinate; and sodium dodecyl sulfate, potassium dodecyl sulfate, ammonium Alkyl sulfate salts such as alkyl sulfate; sodium dodecyl polyglycol ether sulfate; sodium sulforicinoate; sulfone Alkyl sulfonates such as paraffin salts; alkyl sulfonates such as sodium dodecylbenzene sulfonate and alkali metal sulfates of alkali phenol hydroxyethylene; high alkyl naphthalene sulfonates; naphthalene sulfonic acid formalin condensates; sodium laurate, triethanolamine oleate, tri Fatty acid salts such as ethanolamine abietate; polyoxyalkyl ether sulfate ester; polyoxyethylene carboxylic ester sulfate salt; polyoxyethylene phenyl ether sulfate ester; succinic acid dialkyl ester sulfonate salt; polyoxyethylene alkyl aryl sulfate One type or two or more types such as a salt can be used. Since these anionic emulsifiers all have a highly hydrophobic skeleton, all of them exhibit the same effect. By using these anionic emulsifiers, the characteristics of the emulsion for vibration damping materials of the present invention are more effectively exhibited.
Polyoxyalkylene (mono, di, tri) styryl phenyl ether sulfate ester salt is polyoxyalkylene monostyryl phenyl ether sulfate ester salt, polyoxyalkylene distyryl phenyl ether sulfate ester salt, polyoxyalkylene tristyryl phenyl ether salt. It means any of the sulfate ester salts, and the polyoxyalkylene (mono, di, tri) benzyl phenyl ether sulfate salt is a polyoxyalkylene monobenzyl phenyl ether sulfate salt or a polyoxyalkylene dibenzyl phenyl ether sulfate salt. , Or any one of polyoxyalkylene tribenzylphenyl ether sulfate salts.

Examples of compounds particularly suitable as the anionic emulsifier include Latemul WX, Latemuru 118B, Perex SS-H, Emulgen 1118S, Emulgen A-60, B-66 (manufactured by Kao Corporation), New Coal 707SF, New Coal 707SN, Examples include New Coal 714SF, New Coal 714SN (manufactured by Nippon Emulsifier Co., Ltd.), ABEX-26S, ABEX-2010, 2020, 2030, DSB (manufactured by Rhodia Nikka Co., Ltd.) and the like. In addition, surfactants corresponding to these nonionic types can also be used.

As the anionic emulsifier, the reactive emulsifier may be a reactive anionic surfactant, a sulfosuccinate-type reactive anionic surfactant, an alkenyl succinate-type reactive anionic surfactant, or the like. Two or more kinds can be used. 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-2 (Products) Name, manufactured by Sanyo Kasei Co., Ltd.), Adekari Soap SR-10, SR-20, SR-30 (manufactured by ADEKA) and the like. 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, (meth) acrylic acid polyoxyethylene sulfonate salt (for example, “Eleminol RS-30” manufactured by Sanyo Chemical Industries, “Antox MS-60” manufactured by Nippon Emulsifier Co., Ltd.), allyloxymethylalkyloxypolyoxy Sulfate ester (salt) having an allyl group such as sulfonate salt of ethylene (for example, “Aqualon KH-10” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), ammonium polyoxyalkylene alkenyl ether sulfate (for example, “Latemul PD-” manufactured by Kao Corporation 104 "etc.) can also be used.

As the anionic emulsifier, the following surfactants can also be used as reactive emulsifiers. Sulfoalkyl (carbon number 1 to 4) ester salt type surfactant of aliphatic unsaturated carboxylic acid having 3 to 5 carbon atoms, for example, 2-sulfoethyl (meth) acrylate sodium salt, 3-sulfopropyl (meth) acrylate ammonium (Meth) acrylic acid sulfoalkyl ester salt type surfactants such as salts; sulfopropylmaleic acid alkylester sodium salt, sulfopropylmaleic acid polyoxyethylene alkylester ammonium salt, sulfoethylfumaric acid polyoxyethylene alkylester ammonium salt, etc. Aliphatic unsaturated dicarboxylic acid alkyl sulfoalkyl diester salt surfactants.

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. 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.

Among the above surfactants, it is preferable to use a non-nonylphenyl type surfactant from the environmental viewpoint. The amount of the surfactant used may be appropriately set according to the type of surfactant used, the type of monomer component, etc., for example, the total amount of monomer components used to form the emulsion It is preferable that it is 1.0 weight part or more with respect to 100 weight part, More preferably, it is 2.0 weight part or more. More preferably, it is 2.5 parts by weight or more. Moreover, it is suitable that it is 5.0 weight part or less from the point of economical efficiency.

Examples of the protective colloid include polyvinyl alcohols such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, and modified polyvinyl alcohol; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose salt; natural polysaccharides such as guar gum Etc., and one or more of these can be used. The protective colloid may be used alone or in combination with a surfactant. The use amount of the protective colloid may be appropriately set according to the use conditions and the like, for example, 5 weights with respect to 100 parts by weight of the total amount of monomer components used to form the acrylic copolymer. The amount is preferably at most 3 parts by weight, more preferably at most 3 parts by weight.

The polymer in the present invention may be emulsion particles having a core part and a shell part. If the emulsion particles are in such a form, the emulsion for vibration damping material of the present invention will exhibit more excellent effects. Emulsion particles having a core part and a shell part have excellent vibration damping properties over a wide range within the practical temperature range, especially in the high temperature range, compared to other forms of vibration damping composition. Demonstrate. As a result, the damping performance can be exhibited over a wide range from the normal temperature to the high temperature range within the practical temperature range. When the emulsion particles are such, 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 from each other. It may be a core / shell composite structure or a microdomain structure. Among these structures, a core / shell composite structure is preferable in order to sufficiently draw out the characteristics of the emulsion particles and produce stable emulsion particles.
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.

In the emulsion particles having the core part and the shell part, the polymer forming the core part and the polymer forming the shell part include, for example, polymer density, weight average molecular weight, glass transition temperature, SP value (solubility coefficient). ), Any of the various physical properties such as the type of monomer used, the proportion of monomer used, and the like may be used. Among them, it is preferable that there is a difference in at least one of polymer density, weight average molecular weight, and glass transition temperature.

When the particles of the emulsion are emulsion particles having a core part and a shell part, the polymer density is calculated separately for the polymer forming the core part and the polymer forming the shell part, and from the total amount of all polymers. It can be determined by volume fraction. For example, assuming that the total amount of polymers in the emulsion for damping material is 100% by mass, the polymer density of the polymer C forming the core part is C, the polymer density of the polymer forming the shell part is S, and the polymer C When the mass fraction is d mass% and the mass fraction of the polymer S is e mass%, the total polymer density F = (d + e) / (d / C + e / S), that is, (weight of the whole polymer) / ( The volume of the whole polymer).

When the polymer is an emulsion particle having a core part and a shell part, the difference in glass transition temperature (Tg) between the monomer component forming the core part and the monomer component forming the shell part is 10 to 60 ° C. Is preferred. When the difference in Tg is less than 10 ° C. or greater than 60 ° C., there is a possibility that vibration damping properties cannot be obtained over a wide temperature range (20 ° C. to 60 ° C.). More preferably, the difference in Tg is 15 to 55 ° C, and further preferably 20 to 50 ° C.

Moreover, in the emulsion particle | grains which have the said core part and shell part, it is preferable that mass ratio of the monomer component which forms a core part, and the monomer component which forms a shell part is 20 / 80-70 / 30. When the mass ratio of the monomer components forming the core part is smaller than 20/80 or larger than 70/30, there is a possibility that vibration damping properties in a wide temperature range cannot be obtained.

Although it does not specifically limit as pH of the said emulsion for damping materials, For example, it is preferable that it is 2-10, More preferably, it is 3-9. The pH of the emulsion for vibration damping materials can be adjusted by adding ammonia water, water-soluble amines, aqueous alkali hydroxide solution and the like to the emulsion.

Although it does not specifically limit as a viscosity of the said emulsion for damping materials, For example, it is preferable that it is 10-10000 mPa * s. More preferably, it is 50-5000 mPa * s, More preferably, it is 100-2000 mPa * s.
The viscosity can be measured using a B-type rotational viscometer under the conditions of 25 ° C. and 20 rpm.

When the emulsion particles in the present invention are emulsions having a core part and a shell part, it is preferable to obtain the emulsion particles using a usual emulsion polymerization method. Specifically, in the presence of an emulsifier and / or protective colloid, a monomer component is emulsion-polymerized in an aqueous medium to form a core portion, and then the monomer component is further emulsion-polymerized into an emulsion containing the core portion to form a shell portion. It is preferable to obtain by multistage polymerization to form.

The polymerization initiator is not particularly limited as long as it is a substance that decomposes by heat and generates radical molecules, but a water-soluble initiator is preferably used. For example, persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate; water-soluble such as 2,2′-azobis (2-amidinopropane) dihydrochloride, 4,4′-azobis (4-cyanopentanoic acid) Thermal decomposition initiators such as hydrogen peroxide; hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and Rongalite, potassium persulfate and metal salts, redox polymerization of ammonium persulfate and sodium bisulfite, etc. An agent etc. are mentioned, These 1 type (s) or 2 or more types can be used.
The amount of the polymerization initiator used is not particularly limited, and may be set as appropriate according to the type of the polymerization initiator. For example, the total amount of monomer components used to form the polymer is 100 parts by weight. 0.1 to 2 parts by weight, and more preferably 0.2 to 1 part by weight.

In order to promote emulsion polymerization, the polymerization initiator can be used in combination with a reducing agent as necessary. Examples of the reducing agent include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, and glucose; for example, reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite. These 1 type (s) or 2 or more types can be used.
The amount of the reducing agent used is not particularly limited and is preferably 0.05 to 1 part by weight with respect to 100 parts by weight of the total amount of monomer components used to form the polymer.

The polymerization chain transfer agent is not particularly limited, for example, alkyl mercaptans such as hexyl mercaptan, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan; carbon tetrachloride , Halogenated hydrocarbons such as carbon tetrabromide and ethylene bromide; mercaptocarboxylic acid alkyl esters such as mercaptoacetic acid 2-ethylhexyl ester, mercaptopropionic acid 2-ethylhexyl ester, mercaptopyropionic acid tridecyl ester; mercaptoacetic acid methoxybutyl Mercaptocarboxylic acid alkoxyalkyl ester such as ester, mercaptopropionic acid methoxybutyl ester; carboxylic acid mercaptoal such as octanoic acid 2-mercaptoethyl ester Glycol ester or, alpha-methylstyrene dimer, terpinolene, alpha-terpinene, .gamma.-terpinene, dipentene, anisole, allyl alcohol and the like. These may be used alone or in combination of two or more. Among these, it is preferable to use alkyl mercaptans such as hexyl mercaptan, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, and n-tetradecyl mercaptan. The amount of the polymerization chain transfer agent used is usually 2.0 parts by weight or less, preferably 1.0 parts by weight or less, with respect to 100 parts by weight of all monomer components.

The emulsion polymerization may be performed in the presence of a chelating agent such as sodium ethylenediaminetetraacetate, a dispersing agent such as sodium polyacrylate, an inorganic salt, or the like, if necessary. Moreover, as addition methods, such as a monomer component and a polymerization initiator, methods, such as a batch addition method, a continuous addition method, a multistage addition method, are applicable, for example. Moreover, you may combine these addition methods suitably.

Regarding the emulsion polymerization conditions in the above production method, the polymerization temperature is not particularly limited, and is preferably 0 to 100 ° C., and more preferably 40 to 95 ° C., for example. Also, the polymerization time is not particularly limited, and for example, it is preferably 1 to 15 hours, and more preferably 5 to 10 hours.
Moreover, it does not specifically limit as addition methods, such as a monomer component and a polymerization initiator, For example, methods, such as a batch addition method, a continuous addition method, a multistage addition method, are applicable. Moreover, you may combine these addition methods suitably.

In the manufacturing method of the emulsion for vibration damping materials in the present invention, it is preferable to neutralize the emulsion with a neutralizing agent after producing the emulsion by emulsion polymerization. As a result, the emulsion is stabilized. The neutralizing agent is not particularly limited, and for example, tertiary amines such as triethanolamine, dimethylethanolamine, diethylethanolamine and morpholine; ammonia water; sodium hydroxide and the like can be used. These may be used alone or in combination of two or more.

The emulsion for damping material of the present invention can constitute a damping material blend together with other components (components other than the emulsion for damping material). Such a damping material composition essentially including the emulsion for damping material of the present invention is one of the preferred embodiments of the present invention, and forms a damping material capable of exhibiting excellent damping properties. It is something that can be done.

For example, the damping material composition preferably contains 50 to 90% by mass of solid content with respect to 100% by mass of the total amount of the damping material composition. More preferably, it is 60-90 mass%, More preferably, it is 70-90 mass%. Moreover, it is preferable that pH of a damping material compound shall be 7-11. More preferably, it is 7-9.
As a compounding quantity of the emulsion for damping materials in the said damping material composition, the solid content of the emulsion for damping materials will be 10-60 mass% with respect to 100 mass% of solid content of a damping material composition, for example. It is preferable to set so. More preferably, it is 15-55 mass%.

The damping property of the damping material composition can be evaluated by measuring the loss factor of the film formed from the damping material composition.
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. The peak value of the loss coefficient of the film formed from the vibration damping composition is preferably 20% or more. More preferably, it is 21% or more, still more preferably 22% or more, and particularly preferably 23% or more.
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 vibration damping composition of the present invention, the loss factor of the film formed from the vibration damping composition is preferably measured by a resonance method using a cantilever method (3 dB method). The measurement using the cantilever method can be performed using, for example, a CF-5200 type FFT analyzer manufactured by Ono Sokki Co., Ltd.
In addition, the loss factor was applied to a cold rolled steel plate (SPCC-SD: 250 × 10 × 1.6 mm) with a coating volume of 200 × 10 × 3.0 mm, dried at 95 ° C. × 30 minutes, and then 130 It is preferable to measure by forming a film by baking at 60 ° C. for 60 minutes. For example, the loss factor is preferably measured by measuring the loss factor at each temperature of 20 ° C., 30 ° C., 40 ° C., 50 ° C., and 60 ° C. by the resonance method (3 dB method) and evaluating the peak value therein. . In addition, since the practical temperature range of the film formed from the vibration damping composition is usually 20 to 60 ° C., even if the vibration damping performance is evaluated by the total loss coefficient at each temperature of 20 to 60 ° C. Good.

Examples of the other components include a solvent, a plasticizer, a stabilizer, a thickener, a wetting agent, a preservative, a foaming agent, a filler, a colorant, a dispersant, a rust preventive pigment, an antifoaming agent, and an antiaging agent. One type or two or more types of antifungal agents, ultraviolet absorbers, antistatic agents and the like can be used. Among these, it is preferable to include a filler. It is also preferable to include a pigment (colorant or rust preventive pigment).
In addition, the said other component can be mixed with the said emulsion for damping materials etc. using a butterfly mixer, a planetary mixer, a spiral mixer, a kneader, a dissolver etc., for example.

It is preferable that the said damping material formulation has an emulsion for damping materials, a pigment, a foaming agent, and a thickener as essential components. That is, the present invention is also a vibration damping composition containing the above-mentioned emulsion for vibration damping materials, pigment, foaming agent and thickener as essential components. By setting it as such a form, it can be set as the damping material compound which can be used suitably for various uses.

Examples of the pigment (colorant) include organic or inorganic pigments 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.

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 weight part by solid content with respect to 100 weight part of solid content of the emulsion for vibration damping materials. More preferably, it is 0.05-1.5 weight part, More preferably, it is 0.1-1 weight part.
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; Examples of the inorganic filler include glass flakes and mica; and fibrous inorganic fillers such as metal oxide whiskers and glass fibers. As a compounding quantity of an inorganic filler, it is preferable to set it as 50-700 weight part with respect to 100 weight part of solid content of the emulsion for vibration damping materials. More preferably, it is 100-550 weight part. Moreover, it is preferable that the said damping material composition is 50 to 90% of the volume fraction of a filler. By setting it as such a range, favorable coating films, such as heat drying property, are obtained. As a volume fraction of a filler, More preferably, it is 60 to 88%, More preferably, it is 70 to 85%.

As the other component, a foaming agent is preferably used. In this case, as described later, it is preferable to heat-dry the vibration damping composition to form a vibration damping coating film. By further adding a foaming agent to the above damping material emulsion, effects such as formation of a uniform foamed structure of the damping material and thickening of the film are exhibited, resulting in sufficient heat drying properties and high damping. Sex will be expressed. Thus, the damping material composition comprising the damping material emulsion and the foaming agent of the present invention is also one of the preferred embodiments of the present invention. In addition, other components may be further included as necessary.

The foaming agent is not particularly limited, and 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 0.5-5.0 weight part with respect to 100 weight part of emulsion for damping materials. More preferably, it is 1.0 to 3.0 parts by weight.

It is preferable that the vibration damping composition further comprising a foaming agent further comprises an inorganic pigment, thereby more sufficiently exhibiting heat drying properties and high vibration damping properties as described above. It becomes possible to confirm.
It does not specifically limit as said inorganic pigment, For example, 1 type (s) or 2 or more types, such as the inorganic coloring agent mentioned above and an inorganic rust preventive pigment, can be used.

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 for damping materials in a damping material formulation may become the range mentioned above.
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.

As the other component, a polyvalent metal compound may be further used. In this case, the polyvalent metal compound improves the stability, dispersibility, heat drying property, and damping property of the damping material formed from the damping material formulation. It does not specifically limit as a polyvalent metal compound, For example, zinc oxide, zinc chloride, zinc sulfate etc. are mentioned, These 1 type (s) or 2 or more types can be used.
The form of the polyvalent metal compound is not particularly limited, and may be, for example, a powder, an aqueous dispersion, an emulsion dispersion, or the like. Especially, since the dispersibility in a damping material formulation improves, it is preferable to use it with the form of an aqueous dispersion or an emulsion dispersion, More preferably, it is used with the form of an emulsion dispersion. Moreover, it is preferable that the usage-amount of a polyvalent metal compound shall be 0.05-5.0 weight part with respect to 100 weight part of solid content in a damping material compound. More preferably, it is 0.05-3.5 weight part.

The said damping material composition forms the coating film used as a damping material, for example by apply | coating to a base material and drying. The substrate is not particularly limited. Moreover, as a method of apply | coating a damping material compound to a base material, it can apply | coat using a brush, a spatula, an air spray, an airless spray, a mortar gun, a lysing gun etc., for example.
The coating amount of the vibration damping composition may be appropriately set depending on the application, desired performance, etc., but it is preferable that the thickness of the coating film during drying is 0.5 to 8.0 mm. . More preferably, it is 3.0-6.0 mm.
Moreover, it is also preferable to apply so that the surface density of the coating film at the time of drying (after) is 1.0 to 7.0 kg / m ² . More preferably, it is 2.0-6.0 kg / m < ² >. In addition, by using the vibration damping composition of the present invention, it is possible to obtain a coating film that hardly undergoes expansion or cracking during drying and that hardly causes the paint on the inclined surface to slide off.
As described above, the coating method of the damping material composition to be coated and dried so that the thickness of the coating film when dried is 0.5 to 8.0 mm, and the surface density of the coating film after drying. A method of applying a vibration damping composition that is applied so as to be 2.0 to 6.0 kg / m ² and dried is also one of the preferred embodiments of the present invention. Moreover, the damping material obtained by the coating method of the damping material composition is also one of the preferred embodiments of the present invention.

The condition for applying the vibration damping composition and then drying to form a coating film may be heat drying or room temperature drying, but heat drying is preferred from the viewpoint of efficiency. The heat drying temperature is preferably 80 to 210 ° C. More preferably, it is 110-180 degreeC, More preferably, it is 120-170 degreeC.

The emulsion for a vibration damping material of the present invention has the above-described configuration, and can form a good vibration damping material having excellent vibration damping properties at a higher level. And it can keep quietness by preventing vibration and noise in various structures. For example, it is used under the indoor floor of automobiles, railway cars, ships, aircraft, electrical equipment, building structures, construction It can be set as the damping material compound widely used for equipment and the like.

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 examples, various physical properties and the like were evaluated as follows.
<Polymer density>
Using the above-described method, the homopolymer density calculated by the Synthia module (Materials Studio ^R Ver4.3, manufactured by Accelrys Co., Ltd.) and the polymer density of the copolymers used in Examples, Comparative Examples, and Reference Examples are as follows. Calculated. In the calculation of the polymer density, the temperature was set at 298K and the molecular weight was set at 100,000.
Below, the polymer density of each homopolymer calculated about the polymerizable monomer used in Examples 1-5, Comparative Examples 1-3, and Reference Examples 1-2 is shown.
Vinyl acetate (VAc): 1.22 g / cm ³
Methyl acrylate (MA): 1.24 g / cm ³
Ethyl acrylate (EA): 1.15 g / cm ³
2-ethylhexyl acrylate (2EHA): 1.00 g / cm ³
Methyl methacrylate (MMA): 1.16 g / cm ³
Butyl methacrylate (BMA): 1.04 g / cm ³
Styrene (St): 1.07 g / cm ³
Acrylic acid (AA): 1.35 g / cm ³
<Tg>
From the monomer composition used in each stage, the calculation was performed using the above-described Fox formula (the above calculation formula (1)). In addition, Tg calculated from the monomer composition used in all stages was described as “total Tg”. The Tg value of each homopolymer used to calculate the glass transition temperature (Tg) of the polymer synthesized from the polymerizable monomer component is shown below. In addition, the polymer handbook mentioned above was quoted about the glass transition temperature of the homopolymer.
Vinyl acetate (VAc): 30 ° C
Methyl acrylate (MA): 9 ° C
Ethyl acrylate (EA): -22 ° C
2-ethylhexyl acrylate (2EHA): -70 ° C
Methyl methacrylate (MMA): 105 ° C
Butyl methacrylate (BMA): 20 ° C
Styrene (St): 100 ° C
Acrylic acid (AA): 95 ° C

<Weight average molecular weight>
The weight average molecular weight was determined by the GPC (gel permeation chromatography) measurement described above.
<Dynamic viscoelasticity measurement>
The loss tangent was measured under the measurement conditions described above using a dynamic viscoelasticity measuring apparatus (model: RSA III, manufactured by TA Instruments). The same applies to the method for producing the clear film used as the sample.
<Dynamic viscoelasticity measurement>
As described above, the loss factor is measured at 20 ° C., 30 ° C., 40 ° C., 50 ° C., and 60 ° C. using a cantilever method using a CF-5200 type FFT analyzer manufactured by Ono Sokki Co., Ltd. The loss factor was measured by a resonance method (3 dB method). Table 1 below shows the peak values. The same applies to the method for producing a coating film produced from the vibration damping composition.
<Heat drying property>
The prepared aqueous coating composition was applied onto the cationic electrodeposition coated plate so that the dry film thicknesses were 1.5 mm, 3.0 mm, and 4.5 mm. Then, it dried for 30 minutes at 150 degreeC using the hot air dryer, and the swelling and crack generation | occurrence | production state of the obtained dried coating film were evaluated on the following references | standards.
・ Evaluation criteria (visual evaluation)
○: Occurrence of swelling / cracking has not been confirmed △: Slight occurrence of swelling / cracking has been confirmed ×: Many swelling / cracking has occurred

<Nonvolatile content (NV)>
About 1 g of the obtained emulsion for vibration damping materials was weighed, and after 110 hours at 110 ° C. with a hot air drier, the remaining amount of 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, the measurement was performed at 25 ° C. and 20 rpm.

Example 1
35 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 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 33 parts of vinyl acetate, 33 parts of methyl acrylate, 32 parts of ethyl acrylate, 2 parts of acrylic acid, 0.4 part of t-dodecyl mercaptan as a chain transfer agent, polyoxyethylene previously adjusted to a 26% aqueous solution in the dropping funnel. A monomer emulsion consisting of 9.6 parts of alkyl ether sulfate (trade name: Latemul WX, manufactured by Kao Corporation) and 26 parts of deionized water was charged.
The reaction was started by dropping the monomer emulsion into a polymerizer adjusted to 70 ° C., and after raising the temperature to 75 ° C., the monomer emulsion was added over 3 hours while maintaining the internal temperature at 75 ° C. It was dripped uniformly. At the same time, 10 parts of 5% aqueous potassium persulfate solution and 10 parts of 2% aqueous sodium hydrogensulfite solution were uniformly added over 3 hours. After completion of the dropwise addition, the reaction was continued at 75 ° C. for 2 hours to completely consume each monomer. Thereafter, the reaction solution was cooled to 25 ° C. and an appropriate amount of 25% ammonia water was added to obtain an emulsion for vibration damping materials.
The obtained emulsion for vibration damping materials had a non-volatile content of 53.2%, a pH of 7.9, and a viscosity of 110 mPa · s.

Examples 2 to 5, Comparative Examples 1 to 3, and Reference Examples 1 to 2
Except for the monomer compositions shown in Tables 1 and 2 below, an emulsion for vibration damping materials was obtained in the same manner as in Example 1. With respect to the obtained emulsion for vibration damping materials, various physical properties were measured in the same manner as in Example 1, and the results are shown in Tables 1 and 2 below.

Preparation of damping material blends The emulsions for damping materials obtained in Examples 1 to 5, Comparative Examples 1 to 3 and Reference Examples 1 to 2 were blended as follows, and the loss factor and heating were used as damping material blends. Dryability was evaluated. The evaluation results are shown in Tables 1 and 2 below.
Emulsions for damping material 100 parts filler Calcium carbonate NN # 200 ^{* 1} 250 parts Dispersant Aquaric DL-40S ^{* 2} 1 part thickener Acre reset WR-650 ^{* 3} 2 parts Antifoam Nopco 8034L ^{* 4} 0.3 Part blowing agent F-30 ^{* 5} 2 parts * 1: Nitto Flour Chemical Co., Ltd. filler * 2: Nippon Shokubai Co., Ltd. Special polycarboxylic acid type dispersant (active ingredient 44%)
* 3: Nippon Shokubai Co., Ltd. Alkali-soluble acrylic thickener (active ingredient 30%)
* 4: Defoaming agent (main component: hydrophobic silicone + mineral oil) manufactured by San Nopco Co., Ltd.
* 5: Foaming agent manufactured by Matsumoto Yushi

As a result, in Examples 1 to 5 in which the polymer density was 1.11 g / cm ³ or more, the peak value of the loss tangent was 2.5 or more, and excellent vibration damping properties were obtained. Further, the peak value of the loss coefficient was 20% or more. In Comparative Examples 1 to 3, the polymer density was a numerical value less than 1.11 g / cm ³ , and the peak value of loss tangent was also as low as 2.40 or less. In Reference Example 1, the polymer density is 1.11 g / cm ³ or more and high vibration damping properties are obtained, but the weight average molecular weight is 12000 and less than 20000. The swelling of the coating film was observed, and the heat drying property was not sufficient. In Reference Example 2, since the weight average molecular weight was 560000, which was larger than 400000, many cracks of the coating film and peeling from the substrate were observed during heat drying. In addition, due to the large weight average molecular weight, the vibration damping property was lowered as compared with Example 3 produced with the same monomer composition. Moreover, in the storage stability, as in Examples 1 and 3 to 5, the emulsion for a vibration damping material using a polymer polymerized mainly with a (meth) acrylic monomer was excellent. In Example 2 in which polymerization was carried out mainly using vinyl acetate, the polymer particles aggregated when stored for one week at 25 ° C. when used as a vibration damping composition. Examples 1 and 3-5 In the same manner, no aggregation occurred when stored at 25 ° C. for 1 week.
From the above results, it is proved that a vibration damping agent having excellent vibration damping properties can be formed when the polymer density is 1.11 g / cm ³ or more. Furthermore, it has been proved that both heat drying properties can be achieved by controlling the weight average molecular weight.

For reference, the homopolymer density of other compounds is also described below.
Butyl acrylate (BA): 1.07 g / cm ³
Cyclohexyl acrylate (CHA): 1.14 g / cm ³
Methacrylic acid (MAA): 1.22 g / cm ³
Acrylic nitrile (AN): 1.18 g / cm ³
Acrylamide (AAm): 1.27 g / cm ³
Hydroxyethyl acrylate (HEA): 1.30 g / cm ³
Vinyl fluoride: 1.31 g / cm ³
Vinyl chloride: 1.38 g / cm ³

Claims (5)

An emulsion for a vibration damping material composed of a polymer obtained by polymerizing monomer components,
The polymer is 50 to 100% by mass of (meth) acrylic acid, metal salt of (meth) acrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl with respect to 100% by mass of all monomer components to be polymerized. (Meth) acrylic monomers selected from acrylate and butyl methacrylate ;
50-0% by weight of vinyl formate, vinyl acetate, vinyl propionate, scan styrene, divinylbenzene, alpha-methyl styrene, vinyl toluene, ethyl vinyl benzene or we other copolymerizable ethylenically unsaturated monomer selected And a monomer component containing
The polymer has a polymer density of 1.13 g / cm ³ or more and a weight average molecular weight of 20,000 to 400,000.
The emulsion for vibration damping materials is used as an essential component of a vibration damping material composition that is applied to a substrate to form a vibration damping coating film. The polymer, the monomer of the homopolymer density 1.15 g / cm ³ or more, obtained by polymerizing a monomer component containing 20% by mass or more with respect to 100 wt% of the total monomer components to claim 1, wherein The emulsion for damping materials as described. The emulsion for vibration damping materials according to claim 1 or 2 , wherein the polymer has a glass transition temperature of -20 to 40 ° C. The films formed from the emulsion for vibration damping materials is emulsion for vibration damping materials according to any one of claims 1 to 3, wherein the loss tangent in a dynamic viscoelasticity measurement is 2.5 or more. A damping material composition comprising the emulsion for damping material according to any one of claims 1 to 4 , a pigment, a foaming agent, and a thickener as essential components.