JPH0481637B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a sealing material applied to the joints of steel plates, which in particular penetrates into gaps between steel plates at room temperature, further promotes penetration when heated, and does not run off at room temperature or when heated. That is, the present invention relates to a vinyl resin sealing material that does not exhibit drooping properties. (Prior Art) Conventionally, sealants that have fluidity or do not have fluidity have been used to seal joints or joints formed by spot welding or the like in sheet metal members of automobile bodies. However, products that have the former fluidity have the disadvantage that they tend to sag and run off during coating and heating, especially when sealing the joints of steel plates that are close to vertical, and products that do not have the latter fluidity. The sealant does not penetrate into the gap between the steel plates, and when removing excess sealant with a spatula, the coating film becomes extremely thin, or if the coating method is complicated, the sealant may not remain in the defective area. may occur. In this case, water may leak from outside the vehicle body, or the steel plate may rust due to this. In order to solve these problems, Japanese Unexamined Patent Publication No. 57-
As seen in Japanese Patent No. 180678, a sealing material that does not have fluidity at room temperature but becomes fluid when heated has been proposed. (Problems to be Solved by the Invention) However, the fact that the sealant does not have fluidity at room temperature means that it does not conform well to the sealing part, and as shown in FIG. 1
Since it becomes difficult for the sealing material 15 to penetrate into the gap 14 of No. 3, further improvement is required to achieve a complete sealing effect. (Means for Solving the Problems) The present invention has been made by focusing on the above-mentioned conventional problems, and uses vinyl chloride resin, which is a resin with good low-temperature curing properties and a resin with thixotropic properties. By mixing thixotropy imparting agent, thixotropy adjusting agent, resin stabilizer, anti-foaming agent, adhesion imparting agent, filler and plasticizer as a base, the above problems are solved and the permeability into gaps is improved at room temperature. To provide a sealing material which has the following properties and does not exhibit drooping properties at room temperature or when heated. First, as the base vinyl chloride resin, a combination of a low-temperature curing vinyl chloride resin and a copolymer resin of vinyl chloride and vinyl acetate is used, and the mixing ratio of the two is approximately 1:1 to 0.5. When the same amounts are mixed, low-temperature curability is particularly improved, and dripping of the sealant during baking is prevented. In addition, the low-temperature curing resin mentioned here alone lacks physical properties,
On the other hand, if the amount of vinyl chloride vinyl acetate copolymer resin is large, storage stability becomes a problem and costs increase.
Therefore, the amount of vinyl chloride-vinyl acetate copolymer resin in the base vinyl chloride resin is about 30-50%. In addition, the vinyl chloride resin that is the base of these
To 50 to 80 parts by weight, 20 to 50 parts by weight of vinyl chloride resin, which provides high thixotropy by secondary aggregation of fine particles, is mixed as a thixotropy imparting agent to obtain a vinyl chloride resin component. If the amount of vinyl chloride resin used to impart thixotropy is too large, the resin will become too thixotropic and no sagging will occur, but no permeability will be obtained.On the other hand, if too little is used, the permeability effect will be obtained but sag will occur and the workability and appearance will deteriorate. Getting worse. In the present invention, this thixotropy imparting agent is the most important element, and in order to obtain low viscosity, easy penetration, and properties that do not run off, the amount of this high thixotropy resin is smaller than that of the above-mentioned low temperature curing resin. It is necessary that
It is preferably 80% of the low temperature curing resin. What is the vinyl chloride resin that gives steel thixotropy?
When mixed with phthalic acid (DOP), the viscosity was measured by setting the rotational speed of the viscometer to correspond to a shear rate of 0.4 and 9300, and the viscosity of the former was approximately equal to that of the latter. Refers to resin that is 200 times or more. In addition, thixotropy regulators, resin stabilizers, anti-foaming agents, adhesion agents, fillers and plasticizers are blended. As a thixotropy regulator, 30 to 70 parts by weight of resin acid surface-treated calcium carbonate is used. If the amount of this modifier exceeds 70 parts by weight, the physical properties will be impaired.
On the other hand, if the amount is less than 30 parts by weight, sagging will occur, and if only a high thixotropy resin is used, this phenomenon will increase and the problem of high cost will arise. The resin stabilizer functions as an anti-aging agent, and is an organic tin compound, preferably dibutyltin malate, which is added in an amount of 1 to 5 parts by weight. If it is less than 1 part by weight, there will be no effect, and if it is more than 5 parts by weight, the cost will increase, which is not preferable. The antifoaming agent acts as a moisture absorbent, and is made of calcium oxide, which is added in an amount of 5 to 15 parts by weight. Less than 5 parts by weight has no effect;
If it exceeds 15 parts by weight, the amount of moisture absorbed becomes too large, which is not preferable. Modified polyamide and acrylic ester are used as adhesion agents, and are added in an amount of 10 to 30 parts by weight. Normally, modified polyamide and acrylic ester are used alone, but desired physical properties cannot be obtained with modified polyamide alone, and cold resistance and adhesion are poor with acrylic ester alone. However, by using these two together, the physical properties and adhesion can be improved, and it is preferable to add the modified polyamide in an amount of 5 to 10 parts by weight, and the acrylic ester in an amount of 5 to 20 parts by weight. As the modified polyamide, a polymerized fatty acid polycondensate of polyamine is preferably used, and as the acrylic ester, an acrylic ester of trimethylolpropane is preferably used. In the present invention, when actually adding a resin stabilizer, anti-foaming agent, and adhesion imparting agent, each is added in an amount within the above-mentioned range, so that the total amount is 20 to 40 parts by weight. Calcium carbonate, which is commonly used, is used as a filler, but in order to achieve the purpose of the present invention,
100-400 parts by weight is an acceptable range. It is preferable to use a phthalate-based plasticizer, and as a matter of course, too little will result in poor stability, and too much will result in poor physical properties. In the present invention, it is added in an amount of 100 to 200 parts by weight. In addition, "fluidity" used in this specification
A semi-cylindrical sealant with a height of 3 mm and a width of 10 mm is applied to a steel plate coated with a cationic or anionic electrodeposition coating, and then heated at a 70 degree angle for 10 minutes and 140 degrees at room temperature.
The distance that the sealant drips after being held at ℃ for 30 minutes. Also, "permeability" refers to two steel plates coated with cationic or anionic electrodeposition coating, a sealant applied to the joint, held horizontally and at an angle of 70 degrees for 10 minutes at room temperature, and then further heated to 140°C.
This is the distance that the sealant penetrates when two steel plates are separated after being held for 30 minutes and cooled. The sealing material of the present invention having the above configuration is used, for example, in the following manner. That is, as shown in FIG. 1A, the sealing material is discharged in a bead shape onto the seam 3 (for example, a spot welding location) of metal plates 1 and 2 such as steel plates using a sealing gun (not shown), and then The gap 4 is completely sealed by making corrections as shown in FIG. 1B using a brush, spatula, etc., and then heating the sealing material to penetrate into the gap 4. Since the sealing material of the present invention has the above-mentioned physical properties, it can be used for sealing various parts, but it is particularly suitable for sealing at spot welds on automobile bodies, for example, as shown in Fig. 2. It is used to seal gaps in areas such as the roof drip rail 5, trunk opening 6, rear combination lamp 7, and floor 8. Sealing of such gaps in an automobile body is usually carried out in the following steps. That is, after the white body is degreased with an alkaline solution, it is subjected to a chemical conversion treatment using a chemical conversion treatment solution such as an aqueous phosphate solution, and then immersed in a cationic electrodeposition bath or an anionic electrodeposition bath to perform electrodeposition coating. For example, the car body after electrodeposition painting
After baking at 170°C for 30 minutes, apply a sealant to the sealing area having the above-mentioned gap using a sealing gun, and after making corrections, bake at 120 to 170°C for 5 to 20 minutes, preferably at 130°C.
Pre-baking the sealant at ~150°C for 15-20 minutes. Then, if necessary, apply an intermediate coat using a spray coating method, etc., and then heat the coating at 140 to 160℃ for 20 to 30 minutes.
After baking for 40 minutes and applying a topcoat using a spray coating method, etc.
By baking for a minute, the sealing area can be completed at the same time as painting the car body. (Example) Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Examples 1 to 3, Comparative Examples 1 to 10 The raw materials shown in the upper row of Table 1 were mixed and dispersed in the mixing ratios, defoamed under reduced pressure, and sealing materials were prepared. The sealant obtained in this way
The test was conducted in accordance with JISK6830, and the results are listed in Table 1. In addition, as shown in Fig. 2, a sealing gun is used to seal the sealing parts of the automobile body after cationic electrodeposition coating, such as the spot welding gaps of the roof trip rail 5, truck opening 6, rear combination lamp 7, floor 8, etc. The sealing material was applied to the diameter gap using a sealing gun in the form of a bead with a diameter of about 3 mm, a part of which was finished with a brush, and then calcined at 140°C for 10 minutes.
After keeping it at room temperature for 10 minutes, it was further baked at 140°C for 30 minutes to complete the sealing. In this case, evaluate the dripping and permeability during work, and
The table is shown below.

【table】

【table】

[Table] From Table 1, Comparative Example 1 has a large amount of highly thixotropic resin, so no permeability is obtained at all, and Comparative Example 2 has a small amount of highly thixotropic resin, so although it has high permeability, it has high fluidity. , the storage stability tends to deteriorate, and in Comparative Example 3, the elongation is low because the low-temperature curing vinyl chloride resin is much larger than the vinyl chloride vinyl acetate copolymer (PVC/PVAc copolymer) resin. In Example 4, the storage stability is extremely poor when the PVC/PVAc copolymer resin is high, and in Comparative Example 5, the permeability is high when the surface treatment calcium carbonate is low, but the fluidity is high and sag may occur during car body work. Recognize. Furthermore, in Comparative Example 6, if there is a large amount of surface-treated calcium carbonate, permeability cannot be obtained and elongation tends to decrease, Comparative Example 7 cannot obtain adhesive strength if there is a large amount of acrylic ester, and Comparative Example 8 has a modified surface. When the amount of polyamide is large, the storage stability is extremely poor, and in Comparative Example 9, when the amount of calcium carbonate is small, the permeability tends to increase, but the storage stability tends to deteriorate, and in Comparative Example 10, the amount of calcium carbonate is increased,
It can be seen that if the amount of plasticizer is increased at the same time, the fluidity increases, causing sagging during application to a car body, and also reduces the permeability. On the other hand, when the sealant of the present invention was used as a sealant for automobiles, it was confirmed that it penetrated between the steel plates when applied at room temperature, and there was no problem with dripping during work. It was confirmed that this penetration was facilitated, a complete sealing effect was obtained, and there was no sagging. (Effects of the Invention) As explained above, the sealing material of the present invention is based on a low-temperature curing vinyl chloride resin and a vinyl chloride-vinyl acetate copolymer resin, and a specific amount of a highly thixotropic vinyl chloride resin and a thixotropic vinyl chloride resin. The composition contains a conditioner, a resin stabilizer, an anti-foaming agent, an adhesion promoter, a filler, and a plasticizer, so it has appropriate fluidity at room temperature, making it easy to apply and eliminating gaps between steel sheets during application. This penetration is further promoted during heating to provide a complete sealing effect, and the effect is that it does not run off during operation or after baking.

[Brief explanation of the drawing]

FIG. 1A is a perspective view showing a state in which the sealant of the present invention is applied to a steel plate joint with a sealing gun, FIG. 1B is a perspective view showing a modified state of the sealant shown in FIG. 1A, and FIG. 3 is a schematic perspective view showing a portion of an automobile to which a sealing material is to be applied, and FIG. 3 is a sectional view showing a state in which a conventional sealing material is applied to a steel plate joint. 1, 2... Steel plate, 3... Seam, 4... Gap, 5
... Roof drip, 6 ... Trunk opening, 7
...Rear combination lamp, 8...Floor, 1
1, 12... steel plate, 13... joint, 14... gap.

Claims (1)

[Claims] 1. A vinyl chloride resin obtained by adding 20 to 50 parts by weight of a vinyl chloride resin that imparts thixotropic properties through secondary aggregation of microparticles to 80 to 50 parts by weight of a vinyl chloride resin and a vinyl chloride-vinyl acetate copolymer. 100 parts by weight of components, 30 to 70 parts by weight of a thixotropic regulator, 1 to 5 parts by weight of a resin stabilizer,
5 to 15 parts by weight of anti-foaming agent and 10 to 30 parts by weight of adhesion agent
parts by weight, 100 to 400 parts by weight of filler, and 100 parts by weight of plasticizer.
A highly permeable sealant characterized by comprising ~200 parts by weight.