JP5438930B2 - Water-based vibration-damping coating composition - Google Patents

Description

  The present invention relates to an aqueous vibration-damping coating composition that is used in products that generate noise by vibrations such as automobiles, interior materials, metal roofs, building materials, home appliances, motors, and metal products, and that attenuates mechanical vibrations and noises.

  Conventionally, sheet-type damping materials such as asphalt sheets have been used for steel plates such as car bodies in order to impart damping properties. In order to automate the process of pasting this sheet-type vibration damping material or to improve the work environment, a vibration damping material using a water-based vibration damping coating composition made of a polymer has been developed and used (Non-patent Document) 1).

  A damping material using a polymer uses the viscoelasticity of the polymer, and uses a function of converting vibration energy from the outside into heat energy and releasing it to the outside to lose the vibration energy. . However, this damping effect is limited only to a temperature region near the glass transition temperature (Tg) of the polymer. Therefore, the conventional damping material using a polymer has a problem that the usable temperature range showing a high loss coefficient (tan δ) necessary for vibration damping is narrow.

  On the other hand, in order to express vibration damping properties in a wider temperature range, mixing two or more types of polymers having different glass transition temperatures has been performed (Patent Document 1). However, if the mixed polymer is incompatible, a peak of the loss factor appears at each glass transition temperature (hereinafter, the temperature range giving the peak of the loss factor is referred to as a peak temperature range), and a wide peak temperature range. Can't get. Moreover, if compatibility is good, it will become a single peak temperature. Thus, attempts have been made to select and mix semi-compatible polymers. However, although the width of the peak temperature region is widened, there is a problem that the temperature peak height is lowered and the vibration damping performance is lowered.

  In addition, a method has been proposed in which two or more polymers have a mutual network structure, or a compatibilizer is used for an incompatible resin (Patent Document 2). However, the width of the peak temperature range is widened, but there is a problem that the peak height is lowered and the vibration damping performance is lowered.

Also, a method using an inorganic filler such as mica has been proposed in order to reduce the weight of the vehicle body and reduce the manufacturing cost (Patent Document 3). However, when an inorganic filler is added, the loss factor increases. However, when the addition amount is increased, the damping property of the matrix resin is lowered, so that there is a problem that the addition amount cannot be increased.
Japanese Patent Laid-Open No. 9-151335 JP 2001-152028 A Japanese Patent Laid-Open No. 10-060311 “Latest Trends in Polymer Damping Materials and Applied Products”, issued by CMC Co., Ltd., 1997, p. 21

  In recent years, in light of the problem of depletion of energy such as petroleum resources and the problem of the generation of greenhouse gases such as carbon dioxide, automobiles also have a major challenge in reducing the weight of their bodies in order to reduce fuel consumption and exhaust gas. It has become. An object of the present invention is to solve the above-mentioned problems of the conventional water-based vibration-damping coating composition and to provide a water-based vibration-damping coating composition having high vibration-damping performance that contributes to weight reduction of the vehicle body. .

In order to solve the above problems, the aqueous vibration-damping coating composition of the present invention includes at least a matrix resin and a filler, and the matrix resin is a (meth) acrylic copolymer or a styrene acrylic copolymer,
The filler comprises a high aspect ratio inorganic filler, a low aspect ratio inorganic filler, and an organic filler. The high aspect ratio inorganic filler has a weight average aspect ratio of 20 to 90 and a content of 35 to 70% by weight of the total filler components. The low aspect ratio inorganic filler is an organic material having a weight average aspect ratio of 1 to 5, a content of 10 to 30% by weight of all filler components, and the organic filler is in a crystalline state at the use temperature, , a melting point of 60 to 160 ° C., a softening point of 70 to 140 ° C., content of Ri 3 to 40 wt% der of the total filler component, the organic filler, vinylidene chloride, acrylonitrile, acrylic acid, itaconic acid, acrylamide, Monomer selected from the group consisting of methacrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate Characterized in that it is a styrene-acrylic copolymer oligomers containing.

  FIG. 1 is a schematic diagram showing a conventional vibration damping mechanism described in Non-Patent Document 1, in which the horizontal axis indicates the temperature and the vertical axis indicates the value of the loss coefficient (tan δ). When two types of polymers A and B having different temperatures (peak temperatures) giving the peak of the loss coefficient are blended, the peak temperature becomes one when the compatibility is good, and the vibration damping property is exhibited in a wide temperature range. On the other hand, when the compatibility is inferior, the peak temperature does not become one, the loss factor decreases, and the vibration damping performance decreases.

  On the other hand, in the present invention, since an organic material that is in a crystalline state at the use temperature is used for the organic filler, the organic filler is incompatible with the matrix resin. Therefore, the organic filler does not affect the peak temperature of the matrix resin. Since the organic filler is in a crystalline state, it has a high rigidity, is hard, and a vibration damping material having a large vibration damping property can be obtained.

  In the present invention, the SP value of the organic filler is preferably 1 or more larger than the SP value of the matrix resin.

  Here, the SP value is an abbreviation for a solubility parameter, and is an index representing a tendency of solubility of a substance. The SP value is measured or calculated by various methods, and is described in detail, for example, in “Polymer Handbook, Second Edition” by H. Burrell: (1975). The calculation of the SP value of the polymer is described, for example, in “Coating Technology” Vol. 29, No. 6, page 161 (1990).

  In the present invention, the organic filler is preferably a polymer having a weight average molecular weight of 100 to 3500.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based damping paint composition which can manufacture the damping material which has a high loss coefficient in a wide temperature range can be provided.

Hereinafter, embodiments of the present invention will be described in detail.
The aqueous vibration-damping coating composition of the present invention includes at least a matrix resin and a filler, the filler is composed of a high aspect ratio inorganic filler, a low aspect ratio inorganic filler, and an organic filler, and the high aspect ratio inorganic filler is The average aspect ratio is 10 to 200, the content is 35 to 70% by weight of the total filler component, the low aspect ratio inorganic filler is 1 to 5 and the content is 10 to 30% of the total filler component. The organic filler is an organic material that is in a crystalline state at the use temperature, and has a melting point of 40 to 200 ° C. and a content of 3 to 40% by weight of the total filler components. .

  Matrix resins include polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, polyethylene, polypropylene, polyvinyl acetate, vinyl acetate copolymers, (meth) acrylic copolymers, styrene acrylic resins, polyvinylidene fluoride, and polyisoprene. Polymers such as acrylonitrile-butadiene rubber, styrene-butadiene rubber, butadiene rubber, natural rubber, isoprene rubber, polystyrene, styrene acrylic copolymer, polyester, polyurethane, and polyamide can be used. Preferably, it is a (meth) acrylic copolymer or a styrene acrylic resin.

  As an organic filler used by this invention, it is an organic material which is a crystalline state at use temperature, Comprising: What is melting | fusing point is 40-200 degreeC can be used. More preferably, the melting point is 50 to 160 ° C. The content of the organic filler is preferably 3 to 40% by weight of the total filler component. This is because if it exceeds 40% by weight, the loss factor decreases, and if it is less than 3%, the effect of increasing the loss factor is not sufficient.

Specific examples of the organic filler include styrene acrylic copolymer oligomer, low molecular 66 nylon, ethylene terephthalic acid oligomer, urethane oligomer , and cyclic amine.

  Specific examples of cyclic amines include p- (p-toluenesulfonylamide) diphenylamine, (4,4′-bis (α, α-dimethylbenzyl) diphenylamine, N, N′-di-2-naphthyl-p-phenylene. Examples thereof include diamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, and the like.

Furthermore, the SP value of the organic filler is preferably 1 or more larger than the SP value of the matrix resin. Those having a high SP value, a small molecular volume, and a large evaporation energy are preferred. This is because the cohesive force is large and the rigidity is increased.
Therefore, as a monomer used for the styrene acrylic copolymer oligomer, it is preferable to use a monomer having a large SP value. Examples of the monomer having an increased SP value include vinylidene chloride, acrylonitrile, acrylic acid, itaconic acid, acrylamide, methacrylamide, hydroxyethyl acrylate, and hydroxyethyl methacrylate. The SP value of the copolymer may be calculated by multiplying the SP value of each constituent monomer by the constituent mole fraction of the constituent monomer and adding up.

  Moreover, when using a polymer for an organic filler, the weight average molecular weight is 100-3500, More preferably, it is 500-2000. This is because if it is larger than 3500, the movement of the base material tends to be hindered, and if it is smaller than 100, bleeding or separation occurs.

  Further, the organic filler needs to be in a crystalline state at the use temperature. The crystalline state can be confirmed by differential scanning calorimetry (DSC) measurement, X-ray measurement or the like.

  In addition, in order to disperse | distribute an organic filler in matrix resin, the method of adding the emulsion and resin powder containing an organic filler to the resin emulsion and resin solution containing a matrix resin can be used.

  In the present invention, a high aspect ratio inorganic filler having a weight average aspect ratio of 10 to 200 defined by (major diameter of filler / filler thickness) and a low aspect ratio inorganic filler having a weight average aspect ratio of 1 to 5 are provided. Can be used. The aspect ratio of the high aspect ratio inorganic filler is more preferably 20 to 90. As the high aspect ratio inorganic filler, layered inorganic fillers such as mica, graphite, and talc can be used. Moreover, spherical inorganic fillers such as calcium carbonate, clay, and titanium oxide can be used as the low aspect ratio inorganic filler.

  Moreover, it is preferable that the high aspect ratio inorganic filler has a major axis of 100 μm or less, or a thickness or minor axis of 50 μm or less.

  The addition amount of the high aspect ratio inorganic filler is 35 to 70% by weight, more preferably 50 to 65% by weight of the total filler component. If the amount is less than 35% by weight, the effect is not sufficient. If the amount exceeds 70% by weight, the friction effect increases, but the effect of the present invention is hardly exhibited because the frictional effect is too high. Moreover, the addition amount of the low aspect ratio inorganic filler is 10 to 30% by weight, more preferably 10 to 25% by weight of the total filler component.

  A crosslinking agent for crosslinking the matrix can also be added. Generally, the heat resistance of the vibration damping material can be improved by crosslinking the matrix resin, but at the same time the loss factor is lowered. In the present invention, by using at least one crosslinking agent selected from the group consisting of an isocyanate compound, an epoxy compound, and a metal oxide as the crosslinking agent, the reduction in loss factor is suppressed while improving the heat resistance. be able to. These crosslinking agents react with a matrix resin having a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, or an acid anhydride group as a crosslinking reactive group. For example, when a hydroxyl group-containing acrylic copolymer is used for the matrix resin, an isocyanate compound is preferable. Moreover, when using a carboxyl group-containing acrylic copolymer for matrix resin, an epoxy compound and a metal oxide are preferable.

  The isocyanate compound has two or more isocyanate groups in the molecule, and includes aliphatic polyisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate, cyclohexylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and isocyanomethylcyclohexane. And aromatic polyisocyanates such as alicyclic polyisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate. Preferably, it is a polyisocyanate oligomer which is a derivative of a diisocyanate compound. The epoxy compound is a polyvalent epoxy compound having two or more epoxy groups in the molecule, and examples thereof include bisphenol type epoxy compounds, novolac type epoxy compounds, polyglycidyl ethers, and polyglycidyl amines. Examples of the acid anhydride compound include aromatic acid anhydrides such as phthalic anhydride, alicyclic acid anhydrides such as maleic anhydride, and aliphatic acid anhydrides such as polyadipic acid anhydride. A crosslinking agent can also be used individually or in combination of 2 or more types. A catalyst can also be used to improve the reactivity between the matrix resin and the crosslinking agent.

  The resin composition for damping material of the present invention can be molded into various shapes and used as a damping material. For example, the resin composition can be formed into a single sheet by hot pressing or the like and used as an unconstrained vibration damping material, or can be used as a restrained vibration damping material by laminating it between constraining layers that are difficult to deform. It can also be used as a paint type resin composition, applied to a substrate of various shapes to form a coating film, and combined with the substrate.

  Moreover, when using a coating-type resin composition, it is preferable to use an aqueous resin emulsion for the matrix resin and / or the organic filler. The aqueous resin emulsion can be prepared using a known polymerization method such as emulsion polymerization.

EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited to a following example.
Examples 1-4.
As the matrix resin, an emulsion (TT-405, styrene acrylate copolymer, solid content 50%, SP value of about 9.1) manufactured by High Pressure Gas Industry Co., Ltd. was used. As the high aspect ratio inorganic filler, mica having a weight average particle diameter of about 90 μm and a weight average aspect ratio of about 70 was used. As the low aspect ratio inorganic filler, heavy calcium carbonate having a weight average particle diameter of 3 μm and a weight average aspect ratio of about 1 was used. As the organic filler, a crystalline styrene acrylic copolymer oligomer (melting point 70 ° C.) having an SP value of 10.5, a weight average molecular weight of 1800 and incompatible with the matrix resin was used. 150 parts of these fillers were added to 100 parts of the matrix resin. And it dried at normal temperature and obtained the film. The blending ratio of the filler is shown in Table 1.

Example 5 FIG.
The same procedure as in Example 4 was performed, except that the organic filler was changed to p- (p-toluenesulfonylamide) diphenylamine (melting point: about 143 ° C.).

Example 6
The same procedure as in Example 4 was performed, except that mica having a weight average particle diameter of about 30 μm and a weight average aspect ratio of about 20 was used as the high aspect ratio inorganic filler.

Comparative Examples 1-10.
The same procedure as in Example 1 was performed except that the blending ratio of the filler was different.

Comparative Example 11
The same procedure as in Example 1 was performed except that an amorphous styrene acrylic copolymer oligomer having a weight average molecular weight of 4600 was used as the organic filler.

Comparative Example 12
The same procedure as in Example 4 was performed except that mica having a weight average particle diameter of about 10 μm and a weight average aspect ratio of about 5 was used as the high aspect ratio inorganic filler.

(Damping evaluation method)
A central excitation method was used as a test method, and measurement was performed with a loss coefficient measuring device manufactured by B & K.
A coating type damping material was applied to a 300 × 30 × 0.8 mm steel plate (SPCC) so that the surface density was 2.4 kg / m ² to prepare a test piece. The loss factor and bending stiffness ratio were calculated by the impedance method. The results at 45 ° C. converted to 200 Hz are shown in Table 1.

It is a schematic diagram showing a typical dynamic tan δ behavior in a polymer blend system.

Claims (3)

Including at least a matrix resin and a filler,
The matrix resin is a (meth) acrylic copolymer or a styrene acrylic copolymer,
The filler comprises a high aspect ratio inorganic filler, a low aspect ratio inorganic filler, and an organic filler,
The high aspect ratio inorganic filler has a weight average aspect ratio of 10 to 200, and a content of 35 to 70% by weight of the total filler components,
The low aspect ratio inorganic filler has a weight average aspect ratio of 1 to 5 and a content of 10 to 30% by weight of all filler components,
The organic filler is an organic material which is crystalline state at the use temperature, melting point 40 to 200 ° C., content of Ri 3 to 40 wt% der of the total filler component, the organic filler, vinylidene chloride, acrylonitrile, An aqueous vibration-damping coating composition, which is a styrene acrylic copolymer oligomer comprising a monomer selected from the group consisting of acrylic acid, itaconic acid, acrylamide, methacrylamide, hydroxyethyl acrylate, and hydroxyethyl methacrylate .   The water-based vibration-damping coating composition according to claim 1, wherein the SP value of the organic filler is one or more larger than the SP value of the matrix resin.   The water-based vibration-damping coating composition according to claim 1 or 2, wherein the organic filler is a polymer having a weight average molecular weight of 100 to 3,500.

Images