JP2003042223A - Copolymer emulsion for damping material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolymer emulsion for a damping material suitably used as a material comprising a damping compound and providing a water base damping material exhibiting superior heating drying and damping performances. SOLUTION: This copolymer emulsion for the damping material formed by copolymerizing a monomer mixture having an essential acrylic monomer is so formed that gel fraction measured by toluene solvent is 0-45 wt.% and a loss coefficient (tanδ) of a film formed of the damping compound is 0.15 or more.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a copolymer emulsion for vibration damping materials. Specifically, the present invention relates to a copolymer emulsion for vibration damping materials that is preferably used as a constituent of a vibration damping composition.

[0002]

2. Description of the Related Art Damping materials are used to prevent vibrations and noises in various structures to maintain quietness, and are used under the floor of the interior of automobiles, railway cars, ships and aircraft. It may also be used for electrical equipment, building structures, construction equipment, etc. As such a damping material, for example, an asphalt sheet containing an inorganic powder has been used under the interior floor of an automobile, etc., but since it is necessary to heat-bond it, it is possible to improve workability and the like. It has been desired to study various vibration damping composition and polymers for forming vibration damping materials.

Japanese Unexamined Patent Publication No. 9-104842 discloses a water-based vibration-damping coating composition containing a specific amount of at least one color-developing agent selected from a synthetic resin emulsion and an asphalt emulsion, an inorganic filler and a synthetic resin powder. ing. JP-A-11-29737 discloses (a) an aliphatic conjugated diene monomer, (b) an ethylenically unsaturated carboxylic acid monomer, and (c) a monomer other than these monomers. Disclosed is a copolymer latex obtained by copolymerizing in the presence of α-methylstyrene dimer in a specific weight ratio, wherein the loss coefficient (tan δ) and the toluene insoluble content are specified. ing.

Japanese Patent Laid-Open No. 2000-178497 discloses that
Conjugated diene monomer (a), ethylenically unsaturated carboxylic acid amide monomer (b), ethylenically unsaturated carboxylic acid monomer (c), and ethylenically unsaturated monomer (d) other than the above Disclosed is a copolymer latex for a chipping resistant coating obtained by emulsion polymerization of a monomer mixture containing a specific amount of ## STR1 ## in the presence of an inorganic persulfate-based polymerization initiator.
Further, in JP-A-2000-178498, a conjugated diene monomer (a), an ethylenically unsaturated monomer having an epoxy group (b), an ethylenically unsaturated carboxylic acid alkyl ester monomer (c ), A copolymer latex for a vibration damping material obtained by emulsion polymerization of a monomer mixture containing the ethylenically unsaturated monomer (d) other than (b) and (c) in a specific weight ratio is disclosed. ing. Furthermore, JP-A-2000-17
8499 discloses a conjugated diene monomer (a), an epoxy group-containing ethylenically unsaturated monomer (b), an ethylenically unsaturated carboxylic acid amide monomer (c), (b) and ( Disclosed is a copolymer latex for vibration damping materials obtained by emulsion polymerization of a monomer mixture containing an ethylenically unsaturated monomer (d) other than c) in a specific weight ratio.

However, with these techniques, it has not been possible to obtain a damping material which achieves both excellent heat-drying properties and damping properties. That is, when a synthetic resin emulsion or an asphalt emulsion is used, the coating film is dried by heating to dry the surface and moisture in the undried coating film tends to evaporate, which causes blistering. There was room for improvement to improve sex. In addition, as the damping property, the loss factor (tan) of the steel sheet with a 2 mm thick asphalt sheet currently used is
δ) is about 0.1, and it is required to show a value higher than that. A copolymer latex formed from a conjugated diene monomer and other monomer. In the case of using, since the monomer unit formed of the conjugated diene-based monomer does not sufficiently exhibit the vibration damping property, there is room for improvement of the vibration damping property.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and is a copolymer emulsion for a vibration damping material which gives an aqueous vibration damping material exhibiting excellent heat-drying property and vibration damping property. It is intended to provide.

[0007]

The inventors of the present invention have investigated various polymers for damping materials, and a copolymer emulsion for damping materials which gives an aqueous damping material is excellent in workability and the like. First, focusing on the fact that the gel fraction of the copolymer emulsion for vibration damping materials is set to a specific range, the heat drying property becomes excellent and the temperature dependence of the vibration damping property decreases, that is, it is wide. It has been found that it becomes possible to exert damping properties in the temperature range. In addition, when the copolymer emulsion for vibration damping materials is made into a vibration damping composition, the loss coefficient (tan δ) of the coating film formed from the vibration damping composition is set to a specific value or more, whereby an aqueous system is obtained. The vibration damping material can exhibit excellent heat-drying property and vibration damping property, and it has been conceived that the above problems can be solved satisfactorily. Further, the unsaturated monomer having a functional group in the monomer mixture forming the copolymer emulsion is adjusted to a specific amount or less, or the ethylenically unsaturated carboxylic acid monomer and other copolymerizable ethylene It has also been found that when the unsaturated monomer has a specific ratio, it is possible to more sufficiently exhibit excellent heat drying property and vibration damping property in the water-based vibration damping material, and the present invention has been achieved. .

That is, the present invention provides a copolymer emulsion for damping material, which is obtained by copolymerizing a monomer mixture containing an acrylic monomer as an essential component, wherein the copolymer emulsion for damping material is a toluene solvent. It is a copolymer emulsion for vibration dampers, which has a gel fraction of 0 to 45% by weight and a loss coefficient (tan δ) of the coating formed from the vibration damper composition is 0.15 or more. The present invention is described in detail below.

The copolymer emulsion for damping material of the present invention comprises
It is formed by copolymerizing a monomer mixture containing an acrylic monomer as an essential component. The above-mentioned copolymer emulsion for damping material is an aqueous emulsion in which water is used as a continuous phase and a copolymer obtained by copolymerizing a monomer mixture containing an acrylic monomer is dispersed. Usually, the vibration damping material is formed by applying a vibration damping composition containing such a copolymer emulsion for vibration damping materials.

The above-mentioned copolymer emulsion for damping material has a gel fraction of 0 to 45% by weight measured with a toluene solvent.
The gel fraction in the present invention is an index showing the solubility in a toluene solvent of the film formed from the copolymer emulsion for damping material, and the higher the gel fraction is, the lower the solubility in the toluene solvent is. Means The gel fraction reflects the molecular structure of the resin, and if the gel fraction of the copolymer emulsion for damping material of the present invention exceeds 45% by weight, the loss of the coating film formed from the damping material formulation. The coefficient (tan δ) may not exceed 0.15. Further, the temperature dependence of the vibration damping property becomes large, and for example, the vibration damping property has a peak of the vibration damping property in a specific temperature region. In order to exhibit excellent vibration damping properties, the amount is preferably 5 to 45% by weight. More preferably, it is 0 to 30% by weight.

As a method for measuring the above gel fraction, for example,
For example, use the toluene insoluble content measurement method described below.
It is preferable to measureMeasuring method of gel fraction (toluene insoluble matter) 0.2cm thickness of copolymer emulsion for damping material on release paper
Pour it into the Mino formwork and make a film with a thickness of 0.2 cm.
To make. This film is 2 cm (length) x 2 cm (width) x
Cut into 0.2 cm and use as a test film. This test
The film is immersed in 100 ml of toluene, and at room temperature,
Stir with magnetic stirrer for 6 hours. Then 1
It is filtered through a 00 mesh wire mesh, the solid content of the filtrate is determined, and the gel
Calculate the minutes.

In the above copolymer emulsion for damping material, the loss coefficient (tan δ) of the coating formed from the damping material mixture is 0.15 or more. That is, a damping composition was prepared using the copolymer emulsion for damping material of the present invention, and the loss factor (tan δ) of the film formed from this damping composition.
Means 0.15 or more. The vibration damping property, that is, the loss coefficient correlates with tan δ of the coating used, and ta
The higher nδ is, the higher the loss coefficient is and the better the vibration damping property is. When the loss coefficient (tan δ) is less than 0.15, excellent damping properties of the water-based damping material cannot be exhibited. It is preferably 0.16 or more, and more preferably 0.18 or more.

Loss of the coating formed from the above damping composition
As a method of measuring the loss coefficient (tan δ), for example,
Prepare a vibration damper formulation as described in 1.
It is preferable to form a film (test piece) from the compound and measure it.
GoodComposition of damping material Copolymer emulsion for damping material 100 parts by weight Calcium carbonate: NN # 200 (trade name, manufactured by Nitto Koka Kogyo Co., Ltd.) 250 parts by weight Dispersant: Demol EP (trade name, manufactured by Kao Corporation) 1 part by weight Thickener: Acryset AT-2 (trade name, manufactured by Nippon Shokubai Co., Ltd.) 2 parts by weight Defoaming agent: Nopco 8034L (trade name, manufactured by San Nopco) 0.3 parts by weight

[0014]Measuring method of loss factor (tan δ) The above vibration damping composition was applied to a cation electrodeposition coated steel sheet (15 width x 2
50 length x 0.8 mm thickness) and flow into a 3 mm thick mold
Immersion and drying at 150 ° C for 30 minutes were used as test pieces. this
About test pieces Loss factor measurement system made by Ono Sokki Co., Ltd.
Measures the loss factor of the measurement environment at 25 ℃ using the cantilever method
To do.

The copolymer emulsion for damping material of the present invention comprises
When the number average molecular weight is small, in the vibration damping composition that requires the copolymer emulsion for vibration damping material of the present invention, the affinity between the filler such as the inorganic powder and the copolymer emulsion for vibration damping material is improved. Dispersibility is improved. Further, the glass transition point (Tg) is preferably -50 to 40 ° C.
If the Tg is less than -50 ° C or more than 40 ° C, the vibration damping property may not be sufficient. More preferably, −
It is 10 to 20 ° C. The Tg of the copolymer emulsion for damping material can be calculated by the Tg of the homopolymer of each monomer forming the copolymer emulsion for damping material.

The monomer mixture that will form the copolymer emulsion for damping material of the present invention essentially comprises an acrylic monomer, and is not particularly limited as long as the effects of the present invention can be exhibited. Not something. The acrylic monomer means a (meth) acrylic acid derivative such as (meth) acrylic acid or (meth) acrylic acid ester. The content of the acrylic monomer in the monomer mixture is, for example, preferably 50% by weight or more based on the total monomer mixture. In terms of vibration damping properties, the content of the conjugated diene-based monomer in such a monomer mixture is preferably 10% by weight or less based on the total monomer mixture. More preferably, it is 5% by weight or less,
Most preferably, it does not contain a conjugated diene monomer.

In the present invention, the above-mentioned monomer mixture preferably contains less than 10% by weight of an unsaturated monomer having a functional group with respect to the total monomer mixture. The functional group in the unsaturated monomer having a functional group may be any functional group that can be crosslinked when the copolymer emulsion for damping material is obtained by copolymerization. Due to the action of such a functional group, the film-forming property and the heat-drying property of the copolymer emulsion for damping material can be improved. More preferably,
It is 0.1 to 3.0% by weight. The above weight ratio is based on 100% by weight of the total monomer mixture.

Examples of the functional group include an epoxy group, an oxazoline group, a carbodiimide group, an aziridinyl group, an isocyanate group, a methylol group, a vinyl ether group, a cyclocarbonate group and an alkoxysilane group. One kind of these functional groups may be present in one molecule of the unsaturated monomer, or two or more kinds thereof may be present in one molecule.

Examples of the unsaturated monomer having a functional group include polyfunctional unsaturated monomers such as divinylbenzene and ethylene glycol di (meth) acrylate; glycidyl (meth) acrylate and acryl glycidyl ether. And the glycidyl group-containing unsaturated monomers of These may be used alone or in combination of two or more.

In the present invention, the above-mentioned monomer mixture is also used in an amount of 0.1 to 20% by weight of an ethylenically unsaturated carboxylic acid monomer and 99.9 to 10% of another copolymerizable ethylenically unsaturated monomer.
It preferably comprises 80% by weight. By containing an ethylenically unsaturated carboxylic acid monomer, in a vibration damping composition that requires a copolymer emulsion for vibration damping materials, the dispersibility of fillers such as inorganic powder is improved, and the vibration damping property is improved. It will be improved. Further, by containing other copolymerizable ethylenically unsaturated monomer, it becomes easy to adjust Tg, physical properties and the like of the copolymer emulsion for vibration damping materials. In the above-mentioned monomer mixture, if the ethylenically unsaturated carboxylic acid monomer is less than 0.1% by weight or more than 20% by weight, the emulsion may not be stably copolymerized. In the copolymer emulsion for vibration damping material of the present invention, due to the synergistic effect of the monomer units formed from these monomers, the heat-damping property and the excellent vibration damping property in the water-based vibration damping material are more sufficiently exhibited. It becomes possible to do. The above weight ratio is based on 100% by weight of the total monomer mixture.

The ethylenically unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include (meth) acrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, monomethyl fumarate, monoethyl fumarate, monomethylmai. 1 or 2 or more types of unsaturated carboxylic acids or their derivatives such as ates and monoethyl myates.

The above-mentioned other copolymerizable ethylenically unsaturated monomer is not particularly limited, and examples thereof include the above-mentioned unsaturated monomer having a functional group, methyl (meth) acrylate and ethyl (meth) acrylate. Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
(Meth) acrylic acid esters such as cyclohexyl (meth) acrylate; and one or more kinds of aromatic unsaturated monomers such as styrene.

As a method for copolymerizing the above-mentioned monomer mixture, for example, an emulsion polymerization method can be preferably applied. The mode of carrying out emulsion polymerization is not particularly limited, and for example, it can be carried out by appropriately adding a monomer mixture, a polymerization initiator and a surfactant to an aqueous medium and performing copolymerization. Further, a polymerization chain transfer agent or the like may be used for controlling the molecular weight.

The above-mentioned aqueous medium is not particularly limited, and examples thereof include water, a mixed solvent of one or more solvents capable of being mixed with water, or a mixture of such a solvent so that water is a main component. Examples of the mixed solvent include Among these, it is preferable to use water.

The above-mentioned polymerization initiator is not particularly limited,
For example, known water-soluble or oil-soluble initiators such as ammonium persulfate, potassium persulfate, hydrogen peroxide, butyl hydroperoxide and the like can be mentioned. Further, in order to accelerate emulsion polymerization, sodium bisulfite, L
-A redox initiator may be used using ascorbic acid or the like. These may be used alone or in combination of two or more.

The amount of the above-mentioned polymerization initiator to be used is not particularly limited and may be appropriately set depending on the kind of the polymerization initiator, and for example, it is based on 100 parts by weight of the total monomer mixture.
It is preferably 0.1 to 2 parts by weight. More preferably, it is 0.2 to 1 part by weight.

The surfactant is not particularly limited,
For example, any of anionic emulsifiers, nonionic emulsifiers and nonionic anionic emulsifiers can be used. Among these emulsifiers, it is preferable to use a nonionic emulsifier and a nonionic anionic emulsifier from the viewpoint of emulsion polymerization stability, and it is more preferable to use a nonionic emulsifier and a nonionic anionic emulsifier together. Examples of the anionic emulsifier include fatty acid soap, rosin acid soap,
Examples thereof include alkyl sulfonic acid soap, dialkyl aryl sulfonate, alkyl sulfosuccinate, polyoxyethylene alkyl sulfate and the like. As the nonionic emulsifier, for example, polyoxyethylene alkyl ether,
Examples thereof include polyoxyethylene alkylaryl ether, polyoxyethylene sorbitan fatty acid ester, and oxyethyleneoxypropylene block copolymer. These surfactants may be used alone or in combination of two or more.

The amount of the above-mentioned surfactant used is not particularly limited and may be appropriately set according to the type of the emulsifier. For example, with respect to 100 parts by weight of the total monomer mixture,
It is preferably 0.05 to 2.5 parts by weight. More preferably, it is 0.1 to 1 part by weight.

The polymerization chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans such as hexyl mercaptan, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, and n-tetradecyl mercaptan; Halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide, ethylene bromide, etc .; Mercaptocarboxylic acid alkyl esters such as mercaptoacetic acid 2-ethylhexyl ester, mercaptopropionic acid 2-ethylhexyl ester, mercapto pyropionic acid tridecyl ester; mercapto Acetoxy methoxybutyl ester, mercaptopropionic acid methoxybutyl ester and other mercaptocarboxylic acid alkoxyalkyl esters; Octanoic acid 2-mercaptoethyl ester and other carboxylic acid compounds And mercaptoalkyl esters, 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 0 to 1 part by weight, preferably 0 to 0.5 part by weight, based on 100 parts by weight of the total monomer mixture.

In the above emulsion polymerization, if necessary,
It may be carried out in the presence of a chelating agent such as sodium ethylenediaminetetraacetate, a dispersant such as sodium polyacrylate, and an inorganic salt. The addition method of the monomer mixture or the polymerization initiator, for example, a batch addition method, a continuous addition method,
A method such as a multi-stage addition method can be applied. Also, these addition methods may be combined appropriately.

The reaction conditions in the emulsion polymerization are as follows:
It may be appropriately set depending on the composition of the monomer mixture, the polymerization initiator used, and the like. The polymerization temperature is preferably, for example, 5 to 90 ° C. More preferably, it is 20 to 85 ° C. The polymerization time is preferably, for example, 3 to 8 hours. Further, the polymerization and the dropping are preferably performed with stirring.

The copolymer emulsion for damping material of the present invention comprises
The vibration damping composition can be constituted with additives, solvents and the like as required. Such a vibration damping composition, which essentially requires the copolymer emulsion for vibration damping of the present invention, is one of the preferred embodiments of the present invention, and exhibits excellent heat-drying property and vibration damping property. A water-based damping material can be formed.

The amount of the copolymer emulsion for damping material in the above-mentioned damping material compounded is, for example, 100% by weight of the solid content of the damping material, relative to the solid content of the copolymer emulsion for damping material. Is preferably 30 to 60% by weight. The solid content concentration of the vibration damping composition is, for example, 10 to 100% by weight of the vibration damping composition.
It is preferably set to 40% by weight.

Examples of the additives include fillers, colorants, preservatives, dispersants, thickeners, thixotropic agents, antifreezing agents,
Examples thereof include pH adjusters, defoaming agents, wetting agents, rust preventives, adhesion promoters and the like. These may be used alone or 2
You may use together 1 or more types. Among these, it is preferable to include a filler.

The above-mentioned filler is not particularly limited, and examples thereof include inorganic fillers such as calcium carbonate, kaolin, silica, talc, barium sulfate, alumina, iron oxide, titanium oxide and glass talk; glass flakes, mica and the like. Scale-like inorganic fillers: fibrous inorganic fillers such as metal oxide whiskers and glass fibers can be mentioned.

The blending amount of the filler in the vibration damping composition is preferably, for example, 50 to 400 parts by weight with respect to 100 parts by weight of the solid content of the copolymer emulsion for damping material. More preferably, it is 100 to 350 parts by weight.

The solvent is not particularly limited as long as the effects of the present invention are exhibited, and one kind or two or more kinds can be used. Further, the amount of the solvent blended may be appropriately set, for example, so that the solid content concentration of the damping material blend falls within the above range.

The above-mentioned vibration damping composition will be applied to a base material and dried to form a film as a vibration damping material. The base material is not particularly limited.
Further, as a method of applying the vibration damping composition to the substrate, for example, a brush, a spatula, an air spray, an airless spray,
It can be applied using a mortar gun, a ricin gun, or the like.

The conditions for forming the coating by drying after applying the above-mentioned vibration damping composition may be, for example, heat drying or room temperature drying, but in view of efficiency, heat drying is performed. It is preferable, and in the present invention, it is preferable because it is excellent in heat drying property. The heating and drying temperature is preferably 80 to 210 ° C., for example. More preferably, it is 110-160 degreeC.

The application of the vibration damping composition that requires the copolymer emulsion for vibration damping of the present invention is not particularly limited.
Since it is possible to exhibit excellent heat drying properties and vibration damping properties, for example, under the floor of the interior of an automobile, rail cars, ships,
It can be suitably applied to aircraft, electric equipment, building structures, construction equipment and the like.

[0041]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" is
It means "parts by weight".

Example 1 Deionized water was placed in a separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel.
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 126.9 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.9 parts, 2-ethylhexyl acrylate 147.3
Parts, 5.4 parts of glycidyl methacrylate, 5.4 parts of acrylic acid, nonipol 20 previously adjusted to a 25% aqueous solution
0 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Chemical Industry Co., Ltd.) 53.8 parts, Hitenol N-08 adjusted to a 20% aqueous solution (trade name, sulfate salt of polyoxyethylene alkyl ether: Daiichi Kogyo) (Pharmaceutical company)
A monomer emulsion consisting of 21.5 parts and 129.3 parts of deionized water was charged. Next, set the internal temperature of the separable flask to 7
The above monomer emulsion was uniformly added dropwise over 3 hours while maintaining the temperature at 0 ° C. At this time, 53.9 parts of a 5% aqueous potassium persulfate solution and 40 parts of a 2% aqueous sodium hydrogen sulfite solution were uniformly added dropwise over 3 hours. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 25% ammonia water was added to 5.1
Added in parts. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The nonvolatile content of the obtained aqueous resin (copolymer emulsion) is 55.1%,
The pH was 8.8 and the viscosity was 500 mPa · s. Table 1 shows the monomer composition of the above monomer emulsion.

Example 2 A separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel was charged with deionized water 17
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 127.2 parts of methyl methacrylate and styrene 23 were added to the dropping funnel.
0.1, butyl acrylate 170.8 parts, glycidyl methacrylate 5.4 parts, acrylic acid 5.4 parts, 2 in advance
Nonipol 200 adjusted to a 5% aqueous solution (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Chemical Industry Co., Ltd.)
53.8 parts, high tenol N- adjusted to a 20% aqueous solution
08 (trade name, sulfate ester salt of polyoxyethylene alkyl ether: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and a monomer emulsion consisting of 129.3 parts of deionized water were charged. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C.
At the same time, 53.9 parts of a 5% potassium persulfate aqueous solution,
40 parts of a 2% aqueous sodium hydrogen sulfite solution was uniformly added dropwise over 3 hours. After dripping, after aging at 76 ° C for 3 hours,
After cooling, 5.1 parts of 25% aqueous ammonia was added. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The nonvolatile content of the obtained aqueous resin (copolymer emulsion) was 55.0%, and the pH was 8.9.
The viscosity was 550 mPa · s. Table 1 shows the monomer composition of the above monomer emulsion.

Example 3 Deionized water was placed in a separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel.
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 124.2 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.9 parts, 2-ethylhexyl acrylate 147.3
Parts, 5.4 parts of glycidyl methacrylate, 5.4 parts of acrylic acid, 2.7 parts of t-dodecyl mercaptan, 2 in advance.
Nonipol 200 adjusted to a 5% aqueous solution (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Chemical Industry Co., Ltd.)
53.8 parts, high tenol N- adjusted to a 20% aqueous solution
08 (trade name, sulfate ester salt of polyoxyethylene alkyl ether: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and a monomer emulsion consisting of 129.3 parts of deionized water were charged. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C.
At the same time, 53.9 parts of a 5% potassium persulfate aqueous solution,
40 parts of a 2% aqueous sodium hydrogen sulfite solution was uniformly added dropwise over 3 hours. After dripping, after aging at 76 ° C for 3 hours,
After cooling, 5.1 parts of 25% aqueous ammonia was added. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The resulting aqueous resin (copolymer emulsion) has a nonvolatile content of 55.2%, a pH of 9.0,
The viscosity was 620 mPa · s. Table 1 shows the monomer composition of the above monomer emulsion.

Example 4 A separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel was charged with deionized water 17
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 127.1 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.7 parts, 2-ethylhexyl acrylate 147.1
Parts, 5.4 parts of divinylbenzene, 5.4 parts of acrylic acid,
53.8 parts of Nonipol 200 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Chemical Industry Co., Ltd.) adjusted to a 25% aqueous solution in advance, Hitenol N-08 (trade name, polyoxyethylene alkyl ether) adjusted to a 20% aqueous solution Sulfate ester salt: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 21.5
And a monomer emulsion consisting of 129.3 parts of deionized water. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C. At this time, 5% potassium persulfate aqueous solution 53.
9 parts and 40 parts of a 2% sodium hydrogen sulfite aqueous solution were uniformly added dropwise over 3 hours. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 5.1 parts of 25% ammonia water was added. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The obtained aqueous resin (copolymer emulsion) had a nonvolatile content of 55.1%, a pH of 8.7 and a viscosity of 480 mPa · s. Table 1 shows the monomer composition of the above monomer emulsion.

Example 5 A separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel was charged with deionized water 17
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 129.8 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.7 parts, 2-ethylhexyl acrylate 147.1
Part, trimethylolpropane trimethacrylate 2.7
Part, acrylic acid 5.4 parts, nonipol 200 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Kasei Co., Ltd.) adjusted to a 25% aqueous solution in advance, 53.8 parts, Hitenol N-08 adjusted to a 20% aqueous solution. (Commercial name, sulfate salt of polyoxyethylene alkyl ether: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) A monomer emulsion consisting of 21.5 parts and 129.3 parts of deionized water was charged. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C. At this time, 53.9 parts of a 5% aqueous potassium persulfate solution and 40 parts of a 2% aqueous sodium hydrogen sulfite solution were uniformly added dropwise over 3 hours. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 5.1 parts of 25% ammonia water was added. After cooling the emulsions, 10
It was filtered through a 0-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The obtained water-based resin (copolymer emulsion) has a nonvolatile content of 55.0%, a pH of 9.2, and a viscosity of 840 mPa.
It was s. Table 1 shows the monomer composition of the above monomer emulsion.

Comparative Example 1 Deionized water was placed in a separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel.
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 132.3 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.9 parts, 2-ethylhexyl acrylate 147.3
Part, acrylic acid 5.4 parts, nonipol 200 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Kasei Co., Ltd.) adjusted to a 25% aqueous solution in advance, 53.8 parts, Hitenol N-08 adjusted to a 20% aqueous solution. (Commercial name, sulfate salt of polyoxyethylene alkyl ether: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) A monomer emulsion consisting of 21.5 parts and 129.3 parts of deionized water was charged. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C. At this time, 53.9 parts of a 5% aqueous potassium persulfate solution and 40 parts of a 2% aqueous sodium hydrogen sulfite solution were uniformly added dropwise over 3 hours. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 5.1 parts of 25% ammonia water was added. After cooling the emulsions, 10
It was filtered through a 0-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The resulting aqueous resin (copolymer emulsion) has a nonvolatile content of 55.1%, a pH of 8.7, and a viscosity of 430 mPa.
It was s. Table 2 shows the monomer composition of the above monomer emulsion.

Comparative Example 2 Deionized water 17 was added to a separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen introducing tube and a dropping funnel.
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 116.1 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.9 parts, 2-ethylhexyl acrylate 147.3
Parts, glycidyl methacrylate 16.2 parts, acrylic acid 5.4 parts, nonipol 20 previously adjusted to 25% aqueous solution
0 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Chemical Industry Co., Ltd.) 53.8 parts, Hitenol N-08 adjusted to a 20% aqueous solution (trade name, sulfate salt of polyoxyethylene alkyl ether: Daiichi Kogyo) (Pharmaceutical company)
A monomer emulsion consisting of 21.5 parts and 129.3 parts of deionized water was charged. Next, set the internal temperature of the separable flask to 7
The above monomer emulsion was uniformly added dropwise over 3 hours while maintaining the temperature at 0 ° C. At this time, 53.9 parts of a 5% aqueous potassium persulfate solution and 40 parts of a 2% aqueous sodium hydrogen sulfite solution were uniformly added dropwise over 3 hours. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 25% ammonia water was added to 5.1
Added in parts. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The non-volatile content of the obtained aqueous resin (copolymer emulsion) is 55.0%,
The pH was 9.0 and the viscosity was 490 mPa · s. Table 2 shows the monomer composition of the above monomer emulsion.

Comparative Example 3 Deionized water 17 was added to a separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel.
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 116.2 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.9 parts, 2-ethylhexyl acrylate 147.3
Parts, 5.4 parts of glycidyl methacrylate, 5.4 parts of acrylic acid, 10.7 parts of t-dodecyl mercaptan, Nonipol 200 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Kasei Co., Ltd.) adjusted in advance to a 25% aqueous solution. From 53.8 parts, 21.5 parts of Hitenol N-08 (trade name, sulfate ester salt of polyoxyethylene alkyl ether: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) adjusted to a 20% aqueous solution, and 129.3 parts of deionized water Was charged. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C. At the same time, 53.9% 5% potassium persulfate aqueous solution was simultaneously added.
40 parts of a 2% aqueous sodium hydrogen sulfite solution was added dropwise uniformly over 3 hours. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 5.1 parts of 25% ammonia water was added. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The obtained water-based resin (copolymer emulsion) had a non-volatile content of 55.1%, a pH of 8.6, and a viscosity of 410 mPa · s. Table 2 shows the monomer composition of the above monomer emulsion.

Comparative Example 4 Deionized water 17 was added to a separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel.
0.5 parts were charged. Then, the internal temperature was raised to 70 ° C. while stirring under a nitrogen gas stream. On the other hand, 118.8 parts of methyl methacrylate and 25 parts of styrene were added to the dropping funnel.
3.9 parts, 2-ethylhexyl acrylate 147.3
Parts, 13.5 parts divinylbenzene, 5.4 acrylic acid
Parts, nonipol 200 (trade name, polyoxyethylene phenyl ether: manufactured by Sanyo Kasei Co., Ltd.) previously adjusted to 25% aqueous solution 53.8 parts, Hitenol N-08 adjusted to 20% aqueous solution (trade name, polyoxyethylene Sulfate ester salt of alkyl ether: manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 21.
A monomer emulsion consisting of 5 parts and 129.3 parts of deionized water was charged. Next, the monomer emulsion was uniformly added dropwise over 3 hours while maintaining the internal temperature of the separable flask at 70 ° C. At this time, 5% 5% potassium persulfate aqueous solution
3.9 parts, 2 parts of 2% sodium hydrogen sulfite aqueous solution 40 parts 3
It dripped uniformly over time. After completion of dropping, the mixture was aged at 76 ° C. for 3 hours, cooled, and 5.1 parts of 25% ammonia water was added. After cooling these emulsions, they were filtered through a 100-mesh stainless wire mesh and taken out. As a result, an aqueous resin (copolymer emulsion) was obtained. The nonvolatile content of the obtained aqueous resin (copolymer emulsion) is 55.1%, pH.
Was 8.8 and the viscosity was 530 mPa · s. Table 2 shows the monomer composition of the above monomer emulsion.

The following evaluation tests were conducted on the copolymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 4 above. The results are shown in Tables 1 and 2. (1) Gel Fraction (Toluene Insoluble Content) Each of the copolymer emulsions obtained in Examples and Comparative Examples was poured into a 0.2 cm thick mold on a release paper to prepare a 0.2 cm thick film. . This film is 2c
The test film was cut out into m (length) × 2 cm (width) × 0.2 cm. This test film is 100 ml of toluene
And was stirred with a magnetic stirrer for 6 hours at room temperature. Then, the mixture was filtered through a 100-mesh wire net, the solid content of the filtrate was determined, and the gel content was calculated.

(2) Loss factor The copolymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were blended as described below to obtain a damping material blend. A test piece was prepared from the composition of the vibration damping material as described below, and the loss coefficient (tan δ) was measured to confirm the vibration damping property. (Composition of vibration damping compound) Copolymer emulsion 100 parts Calcium carbonate: NN # 200 (trade name, manufactured by Nitto Koka Kogyo Co., Ltd.) 250 parts Dispersant: Demol EP (trade name, manufactured by Kao Co.) 1 part Thickener : Acryset AT-2 (trade name, manufactured by Nippon Shokubai Co., Ltd.) 2 parts antifoaming agent: Nopco 8034L (trade name, manufactured by San Nopco Co.) 0.3 part The above damping composition was subjected to cationic electrodeposition coated steel sheet (15 width) × 2
(50 length × 0.8 mm thickness), it was poured into a 3 mm thick mold and dried at 150 ° C. for 30 minutes to obtain a test piece. About this test piece, loss factor measurement system made by Ono Sokki Co., Ltd.
The cantilever method was used to measure the loss coefficient in a measurement environment of 25 ° C. to evaluate the vibration damping property. That is, the larger the value of the loss coefficient, the better the vibration damping property.

[0053]

[Table 1]

[0054]

[Table 2]

Tables 1 and 2 will be described below.
The emulsion composition is a monomer composition of the monomer emulsion used for producing the copolymer emulsion.

[0056]

EFFECT OF THE INVENTION The copolymer emulsion for vibration damping materials of the present invention, which has the above-mentioned constitution, can be preferably used as a constituent of the vibration damping composition. Further, the vibration damping composition that requires such a copolymer emulsion for vibration damping exhibits excellent heat-drying property and vibration damping property, so that a water-based vibration damping material can be formed.
The invention can be applied to not only the interior floor of automobiles but also railway cars, ships, aircraft, electric equipment, building structures, construction equipment and the like.

Continued front page    F term (reference) 3J048 AA06 BD04 EA36 EA37 EA38                 4J100 AB02P AJ01Q AJ02Q AJ08Q                       AJ09Q AL03P AL04P AL08P                       BC04 CA04 FA20 JA24 JA67

Claims (3)

[Claims] 1. A copolymer emulsion for damping material, which is obtained by copolymerizing a monomer mixture containing an acrylic monomer as an essential component, and the copolymer emulsion for damping material is measured in a toluene solvent. The gel fraction is 0 to 45% by weight, and the loss coefficient (tan δ) of the coating formed from the vibration damping composition is 0.
A copolymer emulsion for a vibration damping material, which is 15 or more. 2. The composition according to claim 1, wherein the monomer mixture contains less than 10% by weight of an unsaturated monomer having a functional group with respect to the total monomer mixture. Copolymer emulsion for vibration materials. 3. The monomer mixture comprises 0.1 to 20% by weight of an ethylenically unsaturated carboxylic acid monomer and 99.9 to 80% by weight of another copolymerizable ethylenically unsaturated monomer. The copolymer emulsion for vibration damping material according to claim 1 or 2, which is characterized by comprising.