JP7059109B2 - How to paint a sealant for automobiles - Google Patents

Description

The present invention relates to a method for coating an automobile sealing material.

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

Further, Patent Document 2 discloses that the heat-shielding and soundproofing paint applied to the roofing material of a building is a synthetic emulsion paint containing a flaky pigment.

Japanese Unexamined Patent Publication No. 4-8778 Japanese Patent Application Laid-Open No. 2003-238879

By the way, for the purpose of improving the fuel efficiency of automobiles, it is required to reduce the weight of each part used in automobiles. In the case of the weather strip, the weight can be reduced by reducing the specific gravity of the rubber material constituting the weather strip, but if the specific gravity of the rubber material is reduced, the sound insulation performance is lowered and the noise outside the vehicle interior is easily transmitted. There is a problem. In other words, it is difficult to achieve both weight reduction and sound insulation performance of the weather strip.

In particular, in recent years, the number of automobiles that do not emit engine noise, such as electric vehicles, has increased, and in the case of such automobiles, the noise emitted by the automobile itself has decreased, so it is small from the outside, which has not been a problem in the past. Intrusion of sound is also subject to sound insulation. For this reason, the demand for sound insulation performance of the weather strip is becoming stricter.

In this regard, Patent Document 1 applies a paint containing fluororesin, glass fiber, carbon fiber, etc. 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.

Further, in Patent Document 2, a heat-shielding and sound-insulating paint containing a flaky pigment is applied to the roofing material of a building, which blocks vibration sounds such as rain noise and weather. An elastically deformable material such as a strip is not an object to be painted, and it is unclear whether even if the weather strip is painted with such a paint, it contributes to the improvement of the sound insulation of the weather strip.

The present invention has been made in view of this point, and an object of the present invention is to make it possible to simultaneously meet the demand for weight reduction of a sealing material for automobiles and the demand for improvement of sound insulation. be.

In order to achieve the above object, the present invention is a coating method for forming a magnesium sulfate fiber-containing coating film on the surface of an automobile sealing material, wherein a magnesium sulfate fiber-containing dispersion liquid in which magnesium sulfate fibers are dispersed in water is used. It is characterized by comprising a step of applying it to the surface of the automobile sealing material and a step of applying a water-based paint wet-on-wet to the coated surface of the magnesium sulfate fiber-containing dispersion liquid in the automobile sealing material. do.

According to this coating method, it is simpler than the method of once mixing the material to be contained in the coating film with the water-based paint and using it. In the method of once mixing with a water-based paint and using it, for example, viscosity adjustment becomes a problem.

Further , by applying the coating composition containing magnesium sulfate fiber to the surface of the sealing material for automobiles, a coating film containing magnesium sulfate fibers is formed on the surface of the sealing material for automobiles. The presence of magnesium sulfate fibers in the coating film enhances sound insulation. It is presumed that the reason is that, for example, the composite of the resin in the coating film and the magnesium sulfate fiber increases the internal loss of the coating film and enhances the sound insulation. Since the intrusion of noise from the outside of the vehicle interior is suppressed by this coating film, the sound insulation property is enhanced when the specific weight of the material of the sealing material for automobiles is reduced to reduce the weight.

In addition, the presence of magnesium sulfate fibers in the coating film improves the slipperiness of the automobile sealant, and the slip resistance when the automobile sealant rubs against another object such as an automobile body or wind glass. Is reduced. Although minute irregularities derived from magnesium sulfate fibers may be formed on the surface of the dry-cured coating film, the sealing function of the sealing material for automobiles (water-stopping when in contact with the vehicle body of an automobile, etc.) Is maintained without inferiority.

Further , the fiber diameter of the magnesium sulfate fiber can be defined as a fiber diameter of 1 nm or more and 1000 nm or less.

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

Further , the water-based coating composition containing at least one of the urethane resin and the silicone resin is advantageous in improving the wear resistance and slipperiness of the sealing material for automobiles.

Further , the magnesium sulfate fiber is contained in an amount of 0.2 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the main resin component (main element for forming a coating film) of the coating composition. do.

As the lower limit of the content of magnesium sulfate fiber, 0.5 parts by mass is more preferable. On the other hand, as the upper limit of the content of magnesium sulfate fiber, 30 parts by mass is more preferable. Here, the main resin component is a main active ingredient that forms a coating film after coating and drying, and can be paraphrased as a coating film forming element or a coating film composition.

When the content of the magnesium sulfate fiber is reduced, the effect of improving the sound insulation and the slipperiness by dispersing the magnesium sulfate fiber in the coating film is diminished. From that point of view, the content is preferably at least the above lower limit. On the other hand, when the content of the magnesium sulfate fiber is large, the coating film becomes brittle and loses its flexibility. From that point of view, the content is preferably not more than or equal to the upper limit.

Further , since the cellulose fiber is further contained , the sound insulation property is further enhanced.

Further , when the coating composition is applied to the surface of the rubber sponge material, the sound insulation can be improved when the specific gravity of the material of the sealing material for automobiles is reduced to reduce the weight. Examples of the sealing material for automobiles include a door weather strip, a door opening seal, a sealing material for a trunk, a glass run channel, and a sealing material for closing a service hole for assembling door equipment of a door panel.

Here, the rubber sponge material is made of EPDM and has a specific gravity of 0.7 or less.

Generally, when the specific gravity of the sound insulating material becomes small, the sound insulating property decreases according to the law of mass. However, although the sound insulation property is certainly lowered as the specific gravity becomes smaller, the coating film in which the magnesium sulfate fiber is present suppresses the deterioration of the sound insulation property due to the decrease in the specific gravity. That is, it is advantageous in simultaneously meeting the conflicting demands of weight reduction and sound insulation improvement .

According to the present invention, since the coating composition applied to the surface of the automobile sealing material contains magnesium sulfate fibers, the demand for weight reduction of the automobile sealing material and the demand for improved sound insulation can be met at the same time. be able to.

It is a perspective view which made a partial cross section which shows the weather strip which concerns on embodiment of this invention. It is an enlarged sectional view which shows a part of the weather strip which concerns on embodiment of this invention. It is a perspective view which shows the outline of the wear resistance test. It is a partial cross-sectional perspective view explaining the method of making a sample of a weather strip. It is sectional drawing which shows the outline of the transmission sound measurement test equipment. FIG. 2 is a diagram corresponding to FIG. 2 according to another embodiment of the present invention.

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 essentially merely an example and is not intended to limit the present invention, its application or its use.

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

The weather strip 1 is interposed between the peripheral edge of the vehicle body door opening (not shown) and the peripheral edge of the door (not shown), and is interposed between the peripheral edge of the vehicle body door opening (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, and the mounting base 2 and the hollow seal portion 3 are integrally molded by a molding method such as an extrusion molding method. ing. The mounting base portion 2 and the hollow seal portion 3 are made of a rubber sponge material 4 (shown in FIG. 2).

The mounting base 2 is mounted on the peripheral edge of the door by a well-known fixing means such as a fastener or 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 edge portion of the door and elastically deforms, whereby the sealing property can be obtained. The cross-sectional shape of the hollow seal portion 3 shown in FIG. 1 is an example, and is not limited to the shape shown in the figure. As shown in FIG. 2, the hollow seal portion 3 is covered with a coating film (resin coating film) 6 containing magnesium sulfate fibers 5 dispersed on the surface of the rubber sponge material 4.

As the rubber material of the rubber sponge material 4, for example, EPDM (ethylene-propylene-diene copolymer) can be preferably used. Other rubber materials or other elastic materials with rubber-like elasticity, such as IR (isoprene rubber), CR (chloroprene rubber), thermoplastic estramer (olefin-based or styrene-based thermoplastic estramer), 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-foaming 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 even more preferably 0.5 or less. Since the rubber sponge material 4 is a material that constitutes most of the weather strip 1, the weight of the weather strip 1 can be significantly reduced by setting the specific gravity of the rubber sponge material 4 to 0.7 or less. ..

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

The coating film 6 can contain a coupling agent such as a carbodiimide, an isocyanate, or a silane coupling agent from the viewpoint of obtaining interfacial adhesion by a chemical bond between the resin which is a coating film forming element and the magnesium sulfate fiber 5.

Magnesium sulfate fiber is a whisker-like basic magnesium sulfate magnesium inorganic fiber obtained by hydrothermal synthesis using magnesium sulfate and magnesium hydroxide as raw materials.

Further, as the magnesium sulfate fiber 5, those having a fiber diameter of nano size (1 nm or more and 1000 nm or less) to about 20 μm or less can be preferably adopted. The average fiber diameter of the magnesium sulfate fiber 5 is more preferably 500 nm or more and 1000 nm or less. The fiber length of the magnesium sulfate fiber 5 is preferably 1 μm or more and 100 μm or less, and the average fiber length is preferably 10 μm or more and 30 μm or less. The specific surface area (surface area per unit volume) of the magnesium sulfate fiber 5 is preferably 1 m ² / g or more and 50 m ² / g or less, and more preferably 7 m ² / g or more and 15 m ² / g or less.

Further, the magnesium sulfate fiber is contained so as to be 0.2 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the main resin component (coating film forming element) of the coating composition according to the embodiment.

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

[Painting method]
The first step of mixing magnesium sulfate fiber 5 with an aqueous paint in which the main resin component (coating film forming element) is dispersed in water to prepare a magnesium sulfate fiber-containing paint composition, and the rubber sponge of the magnesium sulfate fiber-containing paint. It includes a second step of applying to the surface of the material 4 and a third step of drying and curing the coating film obtained in the second step. For the application of the magnesium sulfate fiber-containing paint, for example, the paint gun (spray gun) 13 shown in FIG. 4 or the like can be used, or a blade or the like may be used.

According to this coating method, it is possible to obtain a resin coating film 6 in which magnesium sulfate fibers 5 are evenly dispersed throughout.

<Example / Comparative example>
[Example 1]
Example 1 is a case where a magnesium sulfate fiber-containing resin coating film is formed on the surface of a rubber sponge material by the above-mentioned coating method.

A magnesium sulfate fiber-containing paint having the formulation shown in Table 1 and an EPDM rubber sponge plate (specific gravity 0.48) having a thickness of 2 mm and being extruded and vulcanized were prepared. This magnesium sulfate fiber-containing paint is a mixture of water-based paint and magnesium sulfate fiber. The content of magnesium sulfate fiber is 5 parts by mass with respect to 100 parts by mass of the main resin component (coating film forming element) of the water-based paint. The magnesium sulfate fiber used has a fiber diameter of several hundred nm and a fiber length of 1 to 100 μm.

After degreasing the surface of the rubber sponge plate with thinner, the magnesium sulfate fiber-containing paint having the composition shown in Table 1 was applied to the rubber sponge plate by the coating gun 13 as shown in FIG. After that, the coating film was dried and cured by holding it in an oven at a temperature of 90 ° C. for 10 minutes.

The resin coating film of the sound-insulating sponge material (corresponding to the sealing material for automobiles) 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 magnesium sulfate fibers are removed from the formulation of Example 1, and the same rubber sponge plate as in Example 1 is prepared and the same as in Example 1. A resin coating film containing no magnesium sulfate fiber was formed.

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

The wear resistance in Table 2 is the Gakushin type wear tester (stroke: 150 mm, speed: 60 times / minute) equipped with a glass wearer for wear resistance test (t = 3.5 mm) as shown in FIG. The number of times when the coated surface of the evaluation coating sample was worn or peeled off and the substrate was exposed was examined. The larger the number of times, the better the wear resistance of the coating film.

The static friction coefficient and dynamic friction coefficient in Table 3 were obtained by the following procedure. Using a Haydon tester (HEIDON TRIBOGEAR TYPE32, stylus: glass watch glass, load: 20N), the measured values were obtained by sliding twice at a sliding speed of 1000 mm / min and then sliding the third time. .. The smaller these friction coefficients are, the better the slipperiness of the coating film is.

In Example 1 in which magnesium sulfate fibers were dispersed in the resin coating film, the wear resistance did not change as compared with Comparative Example 1 in which magnesium sulfate fibers were not contained, and the friction coefficient of Example 1 was smaller than that of Comparative Example 1. It can be seen that the slipperiness is excellent.

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

<Sound insulation evaluation>
[Comparison of Example 1 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 was prepared by applying the paints of Examples 1 and Comparative Examples 1 to 4 under the same conditions and methods as in Example 1 described above. The sound insulation 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. A weather strip 1 is sandwiched between the upper and lower jigs 21 and 22, compressed so that the total height is 34% lower, a sound source (90 dB uniform in the reverberation room) is placed on the reverberation room side, and an omnidirectional microphone is placed on the anechoic room side. 23 was arranged and the transmitted sound was measured. Shielding plates 24 and 25 are provided on the reverberation room side of the jigs 21 and 22. The measurement frequency is 100 Hz to 10000 Hz.

By the measurement of the transmitted sound, the sound pressure of Example 1 is lower in the frequency range of 2000 Hz to 3500 Hz than that of Comparative Example 1, and in particular, the sound pressure is lower by about 3 dB at the maximum at 2500 Hz and its vicinity. I understood.

Further, it was found that in Example 1, the sound pressure was lower in the frequency range of 2000 Hz to 3500 Hz than in Comparative Examples 2 to 4, and in particular, the sound pressure was lower by about 3 dB at the maximum in 2500 Hz and its vicinity. rice field.

As described above, although the magnesium sulfate fiber lowered the sound pressure of the transmitted sound, Comparative Examples 2 to 4 were the same as those of Comparative Example 1, and the effect of lowering the sound pressure was not observed in the materials other than the magnesium sulfate fiber.

As described above, according to this embodiment, the coating film containing magnesium sulfate fibers is applied to the surface of the sealing material for automobiles by applying the coating composition containing magnesium sulfate fibers to the surface of the sealing material for automobiles. It can be formed on the surface of the sealing material. The presence of magnesium sulfate fibers in the coating film increases the internal loss of the coating film and enhances the sound insulation. Since the formation of this coating film can suppress the intrusion of noise from the outside of the vehicle interior, it is possible to improve the sound insulation when the specific weight of the material for the automobile sealing material is reduced to reduce the weight.

In addition, the presence of magnesium sulfate fibers in the coating film improves the wear resistance of the automobile sealant, and the automobile sealant slips when it rubs against another object such as an automobile body or wind glass. Resistance is reduced. Micro irregularities derived from magnesium sulfate fibers may be formed on the surface of the dry-cured coating film, but the sealing function of the sealing material for automobiles (water-stopping when in contact with the vehicle body of an automobile, etc.) is inferior. Can be maintained without.

<Example 2>
The above embodiments are merely exemplary in all respects and should not be construed in a limited way. Further, all modifications and modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

In the above embodiment, the coating composition containing magnesium sulfate fibers has been described, but the present invention is not limited to this, and as shown in FIG. 6, the coating composition may further contain cellulose fibers 7.

Cellulose fiber 7 is a fiber obtained from a plant material such as pulp. As the pulp used as a raw material for the cellulose fiber 7, chemical pulp, mechanical pulp, used paper pulp and the like can be adopted.

Examples of chemical pulp include softwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (LKP) and other broadleaf kraft pulp (LKP), softwood bleached kraft pulp (NBKP), and softwood unbleached kraft pulp (NUKP). Pulp (NKP) and the like can be mentioned.

Mechanical pulp includes stone ground pulp (SGP), pressurized stone ground pulp (PGW), refiner ground pulp (RGP), chemi-grand pulp (CGP), thermo-grand pulp (TGP), ground pulp (GP), and thermomechanical. Examples thereof include pulp (TMP), chemithermomechanical pulp (CTMP), and bleached thermomechanical pulp (BTMP).

Waste paper pipes are manufactured from used tea paper, kraft envelope used paper, magazine used paper, newspaper used paper, leaflet used paper, office used paper, cardboard used paper, upper white used paper, Kent used paper, imitation used paper, ground ticket used paper, and sashimi used paper. It is also possible to use deinked pulp (DIP) obtained by deinking used paper pulp.

The pulp may be used alone or in combination of two or more. Other plant raw materials include pulp obtained from linter pulp, hemp, bagasse, kenaf, esparto grass, bamboo, rice husks, straw and the like. Further, wood, hemp, bagasse, kenaf, esparto grass, bamboo, rice husk, straw and the like, which are raw materials for pulp, can be directly used as plant raw materials.

Further, as the cellulose fiber 7, those having a fiber diameter of nano size (1 nm or more and 1000 nm or less) to about 20 μm or less can be preferably adopted. The fiber length of the cellulose fiber 7 is preferably 1 μm or more and 100 μm or less. The specific surface area of the cellulose fiber 7 is preferably 5 m ² / g or more and 600 m ² / g or less.

Such a cellulose fiber 7 can usually be obtained by defibrating a plant raw material (fiber raw material) by a known method. As a manufacturing method when pulp is used as a plant raw material, for example, pulp in an aqueous dispersion state may be subjected to defibration by mechanical treatment, or may be subjected to defibration by chemical treatment such as enzyme treatment or acid treatment. good. Examples of the defibration method by mechanical treatment include a grinder method in which pulp is ground between rotating grindstones, a counter-collision method using a high-pressure homogenizer, and a crushing method using a ball mill, a roll mill, a cutter mill, and the like. Usually, the defibration treatment is repeated until the cellulose fiber 7 obtained by defibrating the pulp has a desired size. In the case of plant raw materials other than pulp, cellulose fibers 7 can be obtained by the same method.

The content of the cellulose fibers 7 in the resin coating film 6 is preferably 0.2% by mass or more and 50% by mass or less. Plant-derived hemicellulose, lignin, and the like related to the raw material of the cellulose fiber 7 may remain in the resin coating film 6.

Similar to Example 1, a coating composition containing both magnesium sulfate fibers 5 and cellulose fibers 7 can be applied to the surface of a rubber sponge material to form a coating film (Example 2).

The second embodiment will be described in detail below. In the second embodiment, since the cellulose fiber 7 is contained in the coating film, there is a problem that the viscosity of the paint becomes very high and it becomes difficult to paint when the cellulose fiber 7 is mixed in the state of the liquid paint which is usually performed and the contained paint is adjusted and painted. .. Therefore, a step of applying the cellulose dispersion liquid in which the cellulose fibers 7 are dispersed in water to the surface of the weather strip and a step of applying the water-based paint to the coated surface of the cellulose dispersion liquid in the weather strip wet-on-wet. It is believed that this can solve this problem.

In Example 2, not only the cellulose fiber 7 but also the magnesium sulfate fiber 5 is dispersed in water, and the cellulose fiber / magnesium sulfate fiber dispersion liquid is applied to the surface of the weather strip, and the cellulose dispersion liquid in the weather strip is used. A step of applying a water-based paint on the coated surface wet-on-wet was performed.

Here, wet-on-wet application means that the cellulose fibers or magnesium sulfate fibers may be wet with water at the stage of applying the water-based paint, and excess water may be removed before applying the water-based paint 12. It may include a step of removing. Here, "wet-on-wet" means that the water-based paint is applied in a state where the cellulose fibers or magnesium sulfate fibers are wet with water over the entire coating layer of the cellulose fibers or magnesium sulfate fibers previously applied. do.

A sample was prepared in which the surface of the hollow seal portion 3 of the weather strip 1 was coated with the water-based paint having the composition shown in Table 4 under the same conditions and methods as in the sound insulation evaluation of Example 1 described above.

In the application of the cellulose dispersion or the cellulose / magnesium sulfate dispersion, after degreasing the surface of the hollow seal portion 3 of the weather strip 1 with a thinner, the cellulose dispersion or the cellulose / magnesium sulfate dispersion is applied to the hollow seal portion by a painting gun. No. 3 was applied, and subsequently, the water-based paint having the composition of Table 4 was applied to the coated surface of the cellulose dispersion liquid or the cellulose / magnesium sulfate dispersion liquid with a painting gun without providing a drying step. After that, the coating film was dried and cured by holding it in an oven at a temperature of 90 ° C. for 10 minutes. That is, a sample was prepared by a wet-on-wet coating method. The coating amount is adjusted by adjusting the number of sprays of the coating gun, etc., and in the cellulose dispersion, the coating film contains 1 to 3 parts by mass of cellulose fibers with respect to 100 parts by mass of the main resin component (coating film forming element) of the water-based paint. Was formed (Comparative Example 5). Further, in the cellulose / magnesium sulfate dispersion, a coating film containing 1 to 3 parts by mass of cellulose fibers and magnesium sulfate fibers is formed with respect to 100 parts by mass of the main resin component (coating film forming element) of the water-based paint. (Example 2). The weather strip 1 is an extruded sponge material (specific gravity 0.48) having a thickness of 2 mm.

As a result of sound insulation evaluation in the same manner as in Example 1, in the case of Example 2 containing both magnesium sulfate fiber 5 and cellulose fiber 7, the frequency of 2000 Hz to 4000 Hz was higher than that of the water-based paint (Comparative Example 1). It was found that the sound pressure became low in the range, and in particular, the sound pressure became low by about 5 dB at 2500 Hz to 3000 Hz and its vicinity.

In comparison with Comparative Example 5 (shown in Table 4) containing only cellulose fiber 7, Example 2 containing both magnesium sulfate fiber 5 and cellulose fiber 7 has a sound pressure in the frequency range of 2500 Hz to 3000 Hz. It was found that the sound pressure became lower and the sound pressure became lower by about 2 dB at the maximum.

As the cellulose fiber 7, a 2% cellulose fiber slurry made from broad-leaved bleached kraft pulp diluted with ion-exchanged water is used, and the fiber diameter of the cellulose fiber is several tens of nm and the fiber length is 1 to 100 μm. .. The magnesium sulfate fiber used has a fiber diameter of several hundred nm and a fiber length of 1 to 100 μm.

[Effect of fiber diameter of cellulose fiber]
Using 2% cellulose fiber slurries having fiber diameters of 10 nm, 100 nm, 1 μm, and 10 μm, respectively, the weather strips having different fiber diameters of the cellulose fibers were prepared according to the conditions and methods of Example 1. Then, the transmitted sound of those weather strips was measured by the equipment shown in FIG.

As a result, it was confirmed that substantially the same sound insulation characteristics can be obtained even if the fiber diameters of the cellulose fibers are different, although there are some variations.

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

1 Weather strip (seal material for automobiles)
2 Mounting base 3 Hollow seal part 4 Rubber sponge material 5 Magnesium sulfate fiber 6 Coating film

Claims (1)

It is a coating method that forms a magnesium sulfate fiber-containing coating film on the surface of a sealing material for automobiles.
A step of applying a cellulose fiber / magnesium sulfate fiber-containing dispersion liquid in which cellulose fibers and magnesium sulfate fibers are dispersed in water to the surface of the automobile sealing material, and
A method for coating an automobile sealant, which comprises a step of applying a water-based paint wet-on-wet to a coated surface of the cellulose fiber / magnesium sulfate fiber-containing dispersion liquid in the automobile sealant.

Images