JP2019206634A - Coating composition, and automobile sealant - Google Patents

Abstract

To fulfill both a request for reduced weight of an automobile sealant and a request for improved sound insulation.SOLUTION: A coating composition is applied to the surface of an automobile sealant and contains fibrous potassium titanate 5.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a coating composition and a sealing material for automobiles on which the coating composition is applied.

  Conventionally, for example, a weather strip is provided as a sealing material in an automobile. In the weather strip, a paint is applied to the surface for the purpose of imparting functions such as wear resistance and slipperiness (slidability). In Patent Document 1, wear resistance is improved by applying a coating composition containing polyurethane, fluororesin, silicone oil, mercaptosilicone, a halogenating agent and a solvent to a weather strip. Among these compositions, It is also disclosed that a part of the fluororesin is replaced with glass fiber, carbon fiber or the like.

  Further, Patent Document 2 discloses that the heat insulating and sound insulating paint applied to the roof material of a building is a synthetic emulsion paint containing flake pigments.

Japanese Patent Laid-Open No. 4-8778 JP 2003-238879 A

  Incidentally, there is a demand for weight reduction in parts used for automobiles for the purpose of improving automobile fuel efficiency. In the case of a weather strip, it is possible to reduce the weight by reducing the specific gravity of the rubber material constituting the weather strip. However, if the specific gravity of the rubber material is reduced, the sound insulation performance is reduced and noise outside the passenger compartment is easily transmitted. There is a problem. In other words, it is difficult to achieve both the weight reduction of the weather strip and the sound insulation performance.

  In particular, in recent years, there has been an increase in the number of cars that do not emit engine noise, such as electric cars. In such cars, the sound emitted by the cars themselves has decreased, and so there has been a small external noise that has not been a problem in the past. Sound intrusion is also subject to sound insulation. For this reason, the request | requirement with respect to the sound insulation performance of a weatherstrip has become severe.

  In this regard, in Patent Document 1, a paint containing fluororesin, glass fiber, carbon fiber, and the like is applied to the weather strip, but this paint is intended to improve wear resistance. It is unclear whether it contributes to improving the sound insulation of the weather strip.

  In Patent Document 2, a heat insulation and sound insulation paint containing flake pigment is applied to a roof material of a building, which blocks vibration noise such as rain noise and weather. What is elastically deformed like a strip is not an object to be coated, and even if the weather strip is painted with such a paint, it is unclear whether it contributes to improving the sound insulation of the weather strip.

  The present invention has been made in view of such points, and an object of the present invention is to be able to simultaneously meet the demand for weight reduction of a sealing material for automobiles and the demand for improvement in sound insulation. is there.

  In order to achieve the above object, the present invention provides a coating composition containing fibrous potassium titanate.

  The first invention is characterized in that the coating composition applied to the surface of the automotive sealing material contains fibrous potassium titanate.

  According to this structure, the coating composition containing fibrous potassium titanate is applied to the surface of the automotive sealing material by applying the coating composition containing fibrous potassium titanate to the surface of the automotive sealing material. Formed on the surface. The presence of fibrous potassium titanate in the coating film increases the sound insulation. The reason for this is presumed that, for example, the internal loss of the coating film increases due to the composite of the resin in the coating film and fibrous potassium titanate, and the sound insulation is increased. Since the invasion of noise from the outside of the passenger compartment is suppressed by this coating film, the sound insulation is enhanced when the specific gravity of the material for the automobile sealing material is reduced to reduce the weight.

  In addition, the presence of fibrous potassium titanate in the coating film improves the wear resistance and slipperiness of the automotive sealing material, and the automotive sealing material rubs against another object such as an automobile body or a window glass. Slip resistance when there is reduced. The surface of the dry-cured coating film may have micro unevenness derived from fibrous potassium titanate. However, the sealing function of the automotive sealing material (water-stopping when it comes into contact with the body of an automobile, etc.) Etc.) is maintained without inferiority.

  The second invention is characterized in that the fiber diameter of the fibrous potassium titanate is nano-sized. The fiber diameter of fibrous potassium titanate being nano-sized can be defined as a fiber diameter of 1 nm to 1000 nm.

  According to this configuration, the effect of suppressing the intrusion of noise from outside the vehicle compartment is improved.

  The third invention is an aqueous coating composition containing at least one of a urethane resin and a silicone resin.

  This configuration is advantageous for improving the wear resistance and slipperiness of the automotive sealing material.

  4th invention is contained so that the said fibrous potassium titanate may be 0.2 to 50 mass parts with respect to 100 mass parts of main resin components (coating film formation main element) of the said coating composition. It is characterized by.

  As a minimum of content of fibrous potassium titanate, 0.5 mass part is more preferable. On the other hand, as an upper limit of content of fibrous potassium titanate, 30 mass parts is more preferable. Here, the main resin component is a main active ingredient that forms a coating film after coating and drying, and can also be referred to as a coating film forming element or a coating film composition.

  When the content of fibrous potassium titanate decreases, the effect of improving sound insulation and slipperiness due to the dispersion of fibrous potassium titanate in the coating film is diminished. From this viewpoint, the content is preferably equal to or higher than the lower limit. On the other hand, if the content of fibrous potassium titanate is increased, the coating film becomes brittle and the flexibility is lost. From this viewpoint, the content is preferably not more than the above upper limit.

  According to a fifth aspect of the present invention, there is provided a sealing material for automobiles, wherein the coating composition is applied to the surface of a rubber sponge material.

  A sixth invention is a sealing material for automobiles, wherein the rubber sponge material is made of EPDM.

  According to this configuration, the sound insulation can be improved when the specific gravity of the material of the automotive sealing material is reduced to reduce the weight. Examples of the automobile sealing material include a door weather strip, a door opening seal, a trunk sealing material, a glass run channel, and a sealing material that closes a service hole for assembling door equipment on a door panel.

  7th invention is characterized by the specific gravity of the said rubber sponge material being 0.7 or less.

  Generally, when the specific gravity of the sound insulating material is reduced, the sound insulating property is reduced due to the law of mass. However, although the sound insulation performance is surely reduced as the specific gravity decreases, the coating film containing fibrous potassium titanate suppresses a decrease in sound insulation performance due to a decrease in specific gravity. In other words, it is advantageous in simultaneously satisfying conflicting demands for weight reduction and sound insulation.

  According to the present invention, since the coating composition applied to the surface of the automotive sealing material contains fibrous potassium titanate, it is necessary to reduce the weight of the automotive sealing material and to improve the sound insulation. You can respond at the same time.

It is the perspective view made into the partial cross section which shows the weather strip which concerns on embodiment of this invention. It is an expanded sectional view showing some weather strips concerning an embodiment of the present invention. It is a perspective view which shows the outline | summary of an abrasion resistance test. It is the perspective view made into the partial cross section explaining the preparation methods of the sample of a weather strip. It is sectional drawing which shows the outline | summary of a transmitted sound measurement test equipment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  A weather strip (door weather strip) 1 schematically shown in FIG. 1 is an automotive sealing material according to an embodiment of the present invention. The sealing material for automobiles is not limited to the weather strip 1 and is not shown. For example, a sealing material for closing a service opening for assembling a door opening seal, a trunk sealing material, a glass run channel, and a door panel door equipment assembly. The shape and size thereof are not particularly limited.

  The weather strip 1 is interposed between a peripheral edge of a door opening (not shown) of the vehicle body and a peripheral edge of the door (not shown), and the peripheral edge of the vehicle body door opening and the peripheral edge of the door. It is a member for sealing between the parts, and has an annular shape. The weather strip 1 can be attached to the peripheral edge of the door.

  The weather strip 1 includes a mounting base 2 attached to the peripheral edge of the door, and a hollow seal portion 3. The mounting base 2 and the hollow seal portion 3 are integrally formed by a molding method such as an extrusion molding method. ing. The mounting base 2 and the hollow seal portion 3 are composed of a rubber sponge material 4 (shown in FIG. 2).

  The attachment base 2 is attached to the peripheral portion of the door by a well-known fixing means such as a fastener or a double-sided tape (not shown). When the door is in the closed state, the hollow seal portion 3 is pressed against the vehicle body by the peripheral portion of the door and is elastically deformed, thereby obtaining a sealing property. The cross-sectional shape of the hollow seal portion 3 shown in FIG. 1 is an example, and is not limited to the illustrated shape. As shown in FIG. 2, the hollow seal portion 3 is formed by covering the surface of the rubber sponge material 4 with a coating film (resin coating film) 6 in which fibrous potassium titanate 5 is dispersed and contained.

  As the rubber material of the rubber sponge material 4, for example, EPDM (ethylene-propylene-diene copolymer) can be preferably used. For example, other rubber materials or other elastic materials having rubber-like elasticity such as IR (isoprene rubber), CR (chloroprene rubber), thermoplastic elastomer (olefinic or styrene thermoplastic elastomer), soft polyvinyl chloride, etc. It can also be used. The material of the rubber sponge material 4 may be a mixture of a plurality of types. Further, the weather strip 1 may be partially formed of a solid material (non-foamed material).

  The rubber sponge material 4 covered with the coating film 6 preferably has a specific gravity of 0.7 or less. The specific gravity of the rubber sponge material 4 is more preferably 0.6 or less, and still more preferably 0.5 or less. Since the rubber sponge material 4 is a material constituting most of the weather strip 1, the weather strip 1 can be significantly reduced in weight by setting the specific gravity of the rubber sponge material 4 to 0.7 or less. .

  As the resin component (coating film forming element) of the coating film 6, a urethane resin or a silicone resin can be preferably used. A urethane resin and a silicone resin may be used in combination. For example, other resins such as an acrylic resin, a vinyl chloride resin, and an epoxy resin may be used.

  The coating film 6 may contain a coupling agent such as carbodiimide, isocyanate, and silane coupling agent from the viewpoint of obtaining interfacial adhesion by chemical bonding between the resin as the coating film forming element and the fibrous potassium titanate 5. it can.

  Fibrous potassium titanate can be obtained by a firing method in which a mixture of potassium carbonate and titanium oxide is used as a raw material, for example, fired at a temperature of about 600 ° C. to 1200 ° C. and synthesized by a solid phase reaction. In addition, it can be obtained by a melting method. Fibrous potassium titanate can also be called potassium titanate whisker (potassium titanate whisker).

  As the fibrous potassium titanate 5, one having a fiber diameter of about nanometer (1 nm or more and 1000 nm or less) to 20 μm or less can be preferably used. The fiber diameter of the fibrous potassium titanate 5 is more preferably 300 nm or more and 600 nm or less. The fiber length of the fibrous potassium titanate 5 is preferably 1 μm or more and 100 μm or less, and more preferably 10 μm or more and 20 μm or less.

  Further, fibrous potassium titanate is contained in an amount of 0.2 to 50 parts by mass with respect to 100 parts by mass of the main resin component (coating film forming element) of the coating composition according to the embodiment.

<Method for producing weather strip 1>
The weather strip 1 can be obtained by forming the coating film 6 on the surface of the rubber sponge material 4 by painting. As the coating method, the following coating method can be employed.

[Coating method]
A first step of preparing a fibrous potassium titanate-containing coating composition by mixing fibrous potassium titanate 5 with an aqueous coating material in which a main resin component (coating film forming element) is dispersed in water; A second step of applying a potassium-containing paint to the surface of the rubber sponge material 4 and a third step of drying and curing the coating film obtained in the second step are provided. For example, a coating gun (spray gun) 13 shown in FIG. 4 can be used for applying the fibrous potassium titanate-containing paint, or a blade or the like may be used.

  According to this coating method, it is possible to obtain the resin coating film 6 in which the fibrous potassium titanate 5 is uniformly dispersed throughout.

<Examples and comparative examples>
[Example]
An example is a case where a fibrous potassium titanate-containing resin coating film is formed on the surface of a rubber sponge material by the above-described coating method.

  A fibrous potassium titanate-containing paint having the composition shown in Table 1 and a 2 mm thick extruded vulcanized EPDM rubber sponge plate (specific gravity 0.48) were prepared. This fibrous potassium titanate-containing paint is obtained by mixing fibrous potassium titanate with an aqueous paint. The content of fibrous potassium titanate with respect to 100 parts by mass of the main resin component (coating film forming element) of the water-based paint is 5 parts by mass.

  The fiber potassium titanate used has a fiber diameter of several hundred nm and a fiber length of 1 to 100 μm.

  After the surface of the rubber sponge plate was degreased using thinner, a fibrous potassium titanate-containing paint having the composition shown in Table 1 was applied to the rubber sponge plate with a coating gun 13 as shown in FIG. Thereafter, the coating film was dried and cured by holding it at 90 ° C. for 10 minutes in an oven.

  The resin coating film of the sound insulating sponge material (corresponding to an automobile sealing material) obtained as described above had a dry film thickness of 6 to 9 μm.

[Comparative Example 1]
As shown in Table 1, Comparative Example 1 is a water-based paint having a composition in which fibrous potassium titanate is removed from the composition of Example 1, and the same rubber sponge plate as that of Example is prepared. Thus, a resin coating film containing no fibrous potassium titanate was formed.

[Evaluation of the physical properties]
The physical properties of the sound-insulating sponge material (evaluation coating sample) of Examples and Comparative Example 1 were examined. The results are shown in Table 2.

  The wear resistance shown in Table 2 is the same as shown in FIG. 3, the Gakushin type wear tester equipped with a glass wear piece for wear resistance test (t = 3.5 mm) (stroke: 150 mm, speed: 60 times / min) The number of times when the coated surface of the evaluation coating sample was worn or peeled and the substrate was exposed was examined. It shows that the abrasion resistance of a coating film is excellent, so that this frequency | count is large.

  The static friction coefficient and dynamic friction coefficient in Table 3 were obtained by the following procedure. Using a Haydon tester (HEIDON TRIBOGEAR TYPE32, measuring element: glass watch glass, load: 20 N), a sliding value was obtained by sliding twice at a sliding speed of 1000 mm / min. . It shows that the slipperiness of a coating film is excellent, so that these friction coefficients are small.

  The example in which the fibrous potassium titanate is dispersed in the resin coating film is more than twice the wear resistance compared to the comparative example not containing fibrous potassium titanate. It is smaller than the example, and it can be seen that the slipperiness is excellent.

<Comparative Examples 2-4>
As in the example, 5 parts by mass of the material shown in Table 3 was added to 100 parts by mass of the main resin component (coating film forming element) of the coating composition in the water-based paint of Comparative Example 1 and the same as in the example. A rubber sponge plate was prepared, and a resin coating film was formed in the same manner as in Example 1.

<Sound insulation evaluation>
[Comparison of Examples and Comparative Examples 1 to 4]
As shown in FIG. 4, a sample in which the surface of the hollow seal portion 3 of the weather strip 1 was coated with the paints of the examples and comparative examples 1 to 4 by the same conditions and methods as in the above-described examples was prepared. Sex was evaluated. The weather strip 1 is an extruded sponge material (specific gravity 0.48) having a thickness of 2 mm.

  FIG. 5 shows a sound insulation test facility. The weather strip 1 is sandwiched between the upper and lower jigs 21 and 22 and compressed so that the total height is 34% lower. 23 was placed and the transmitted sound was measured. Shield plates 24 and 25 are provided on the reverberation chamber side of the jigs 21 and 22. The measurement frequency is 100 Hz to 10000 Hz.

  According to the measurement of transmitted sound, the sound pressure in the example is lower in the frequency range of 2000 Hz to 3500 Hz than in Comparative Examples 1 to 4, and particularly at 2500 Hz and its vicinity, the sound pressure is reduced by about 3 dB at the maximum. I understood it.

  In addition, it was found that the sound pressure in the example was lower in the frequency range of 2000 Hz to 3500 Hz than in Comparative Examples 2 to 4, and in particular at 2500 Hz and its vicinity, the sound pressure was reduced by about 3 dB at the maximum. .

  Thus, although fibrous potassium titanate lowered the sound pressure of the transmitted sound, Comparative Examples 2 to 4 were not different from Comparative Example 1, and the effect of lowering the sound pressure on materials other than fibrous potassium titanate was recognized. There wasn't.

  As described above, according to this embodiment, the coating composition containing fibrous potassium titanate is applied to the surface of the automotive sealing material to thereby apply the coating composition containing fibrous potassium titanate. A film can be formed on the surface of a sealing material for automobiles. The presence of fibrous potassium titanate in the coating film increases the internal loss of the coating film and increases the sound insulation. Since the intrusion of noise from the outside of the passenger compartment can be suppressed by the formation of this coating film, the sound insulation can be enhanced when the specific gravity of the material for the automobile sealing material is reduced to reduce the weight.

  In addition, the presence of fibrous potassium titanate in the coating film improves the wear resistance and slipperiness of the automotive sealing material, and the automotive sealing material rubs against another object such as an automobile body or a window glass. Slip resistance when there is reduced. The surface of the dry-cured coating film may have minute irregularities derived from fibrous potassium titanate, but the sealing function of automotive sealing materials (water-stopping when contacting a car body, etc.) Can be maintained without inferiority.

  The above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the present invention can be applied to, for example, a weather strip for automobiles.

1. Weather strip (automobile sealant)
2 Mounting base 3 Hollow seal part 4 Rubber sponge material 5 Fibrous potassium titanate 6 Coating film

Claims (7)

In the coating composition applied to the surface of the sealing material for automobiles,
A coating composition comprising fibrous potassium titanate. The coating composition according to claim 1,
The fiber composition of the fibrous potassium titanate is nano-sized. The coating composition according to claim 1 or 2,
A coating composition comprising an aqueous coating composition containing at least one of a urethane resin and a silicone resin. In the coating composition according to any one of claims 1 to 3,
The coating composition, wherein the fibrous potassium titanate is contained in an amount of 0.2 to 50 parts by mass with respect to 100 parts by mass of the main resin component of the coating composition.   An automotive sealing material, wherein the coating composition according to any one of claims 1 to 4 is applied to a surface of a rubber sponge material. The automotive sealing material according to claim 5,
The automotive sealing material, wherein the rubber sponge material is made of EPDM. The automobile sealing material according to claim 5 or 6,
A sealing material for automobiles, wherein the rubber sponge material has a specific gravity of 0.7 or less.

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