JPH0230747B2 - BODEISHIIRAANOTOFUHOHO - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method of applying a body sealer to fill gaps in joints of steel plates of vehicles, for example. [Prior art] Seams and joints of steel plates and members of vehicles, etc.
A bead of body sealer is applied to fill in the gaps. On top of that, the next step is intermediate coating and top coating. Body sealers are used during storage after application or during heating and drying of the paint film during the intermediate coating and top coating processes.
The viscosity is high to prevent it from dripping. Therefore, during application, it is difficult to penetrate into the gaps between joints and joints, and it is necessary to push it in with a brush, spatula, etc. This pushing operation scrapes off the body sealer at the edge portion of the steel plate, exposing the steel plate, which is unfavorable in terms of rust prevention. JP-A-57-180678 discloses a method of imparting sealing properties to gaps by heat flow effect,
JP-A-59-131668 discloses a body sealer that self-penetrates into gaps to provide sealing properties. Spray coating is generally known as a method for coating paints, vinyl chloride resin plastisol undercoats, and high viscosity liquids. Japanese Patent Publication No. 52-105947
The publication discloses a method in which a high viscosity liquid can be sprayed by heating it within the spray gun or on the way to the gun. [Problems to be Solved by the Invention] The method disclosed in JP-A-57-180678 and the body sealer disclosed in JP-A-59-131668 are not effective in sealing gaps. However, it is insufficient to cover the edges of the steel plates at joints. When a conventional vinyl chloride plastisol is used as a body sealer for spray application, there are problems in that it splatters and the applied surface becomes earthworm skin, making it undesirable to use as a body sealer. The heating method disclosed in JP-A-52-105947 has the risk of gelling the body sealer and requires a considerable amount of heat for heating.
It's not a good method. The present invention overcomes the drawbacks of the above-mentioned conventional methods,
It is an object of the present invention to provide a method for applying a body sealer that has good sealing properties, good covering properties, a smooth application surface, and can be easily applied. [Means for Solving the Problems] In order to solve the problems, the method of applying a body sealer to which the present invention is applied is to apply a plasticizer to a vinyl chloride resin, a vinyl chloride copolymer resin, or a blend resin of these resins. The kinematic viscosity (shear rate 9410 sec ^-1 ) is 2000 cps or less, and the static viscosity (shear rate 4.2 sec ^-1 ) is 15000 to 70000 cps by mixing the adhesive and adhesion promoter.
The method used is to spray a sealer adjusted to the desired temperature into the gaps. The base resin of the body sealer is a single resin of vinyl chloride, a copolymer resin of vinyl chloride, or a blend resin thereof. Copolymer resins include, for example, vinyl chloride and vinyl acetate, vinylidene chloride, acrylic ester, maleic anhydride, or maleic acid. It is a copolymer with acid ester, etc. Examples of plasticizers include phthalate esters such as butylbenzyl phthalate (BBP), diisodecyl phthalate (DIDP), di-2-ethylhexyl phthalate (DOP), di-2-ethylhexyl adipate (DOA), and butyl phthalyl butyl glycosyl phthalate. Polyester plasticizers such as phthalate-based, adipic-acid, and trimethic acid-based plasticizers can be used. Fillers include, for example, calcium carbonate (CaCO ₃ ),
Clay, talc, bentonite, kaolin, zinc white, titanium oxide, silica, etc. are used. As the adhesion promoter, for example, acrylic, amine, or imine adhesives can be used. [Operation] According to the method of the present invention, the kinematic viscosity (corresponding to the viscosity during spraying) of the body sealer is as low as 2000 cps or less, so the body sealer is easy to spray during application. On the other hand, since the static viscosity (corresponding to the viscosity after application) is 15,000 to 70,000 cps, the leveling of the coated surface is good and there is no sagging during heating and drying. Experiments have shown that the kinematic viscosity of body sealer is
If it is over 2000cps, it will not become a spray. Also 2000cps
Even if it is below, if the static viscosity is 70,000 cps or more, the leveling of the surface to which the body sealer is applied will be poor, resulting in a vermiform skin. and the static viscosity is
If it is less than 15,000 cps, the body sealer will sag during heating drying in the next process. [Example] Examples of the present invention will be described in detail below. First, adjust the body sealer. Base resin (vinyl chloride or vinyl chloride copolymer), plasticizer (butylbenzyl phthalate, di2-ethylhexyl phthalate), filler (particle size 1.5 μm calcium carbonate, particle size 0.07 μm calcium carbonate), adhesive A body sealer is obtained by weighing and mixing the agents (amine type) at the weight ratios (Wt%) shown in Table 1.
The static viscosity of the obtained body sealer was measured at a shear rate of 4.2 sec ^-1 using a BH type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd.), and the static viscosity at a shear rate of 9410 sec ^-1 was measured using a capillary extrusion viscometer (manufactured by Rigosha Co., Ltd.). Measure the kinematic viscosity of each.
Your BH type rotational viscometer rotates a rotor immersed in a sample slowly at a constant speed, measures the torque received from the sample, and converts it into viscosity. The latter type of capillary extrusion type viscometer measures the speed at which a sample passes through a capillary under a constant pressure and converts it into viscosity. Among the body sealers mixed at the weight ratio in Table 1, the examples shown in Examples 1 to 5 have a kinematic viscosity of 2000 cps.
The following sealer has a static viscosity adjusted to 15,000 to 70,000 cps and is used in the method of applying the present invention. The examples shown in Comparisons 1 to 4 have either dynamic viscosity or static viscosity outside the above range, and are sealers to which the present invention is not applicable. When the body sealers of each of the above examples were subjected to a heat-resistant flow test according to JISK-6830, the heat-resistant flow (mm)
As shown in Table 1, it suggests that there is no risk of the body sealer sagging during heating. Furthermore, the body sealer of each of the above examples is sprayed using a spray device. The spray device uses a known airless or air spray gun. For the experiment, apply in the positional relationship shown in the figure. Open a gap d of 1 mm between flat steel plate 1 and L steel plate 2, and use the material bonded together by spot welding at positions P ₁ and P ₂ , and spray toward this gap at a 45 degree angle from a distance of 50 mm from the gap. Apply with gun 3. The pressure applied to the sealer with gun 3 is 3Kg/cm ² . The sprayability at this time is as shown in Table 1, where the kinematic viscosity (viscosity during spraying) of the sealer is 2000 cps.
If it's less than that, it's generally good, but if it's more than that, it gets extremely bad. Also, for the finished appearance of spray coating, the lower the kinematic viscosity of the sealer, the better for both the degree of scattering and smoothness (leveling). In order to check whether the sealing property is good or not, the L steel plate 2 is peeled off from the flat steel plate 1, and the penetration distance of the body sealer is measured. In other words, 1 of flat steel plate 1 and L steel plate 2
Check how much the body sealer has penetrated into the gaps of mm. As shown in Table 1, the lower the kinematic viscosity and static viscosity, the longer the penetration distance and the better the sealing performance. Next, we conducted the following experiment to investigate the characteristics of multiple coatings. Apply body sealer in the same way as above to the board that has been electrodeposited with anti-rust paint. After preheating it, apply an intermediate coat of 20 μm and a top coat of 20 μm, then dry. When the completed painted surfaces were visually inspected to judge whether they were good or bad, as shown in Table 1, all the examples to which the present invention was applied were beautiful. The pressure applied to the sealer by a spray gun during application is relatively low, preferably 5 kg/cm ² or less; if it is higher than that, the body sealer may scatter. The thickness of the coating film is preferably 0.7 to 3.0 mm; if it is less than 0.7 mm, the edge portions of the steel plate will be insufficiently coated, and if it is thicker than 3.0 mm, sagging may occur. [Effects of the Invention] As explained above, in the body sealer application method to which the present invention is applied, since the viscosity of the sealer is set as above, it has good sprayability and can be applied over a wide area. can be reliably sealed, and the sealing and covering properties are improved. Since there is no need to correct the body sealer by pushing it in, there is no need to worry about the edges being exposed, and by eliminating the correction process, the work time can be shortened. No sagging during heating or drying in the next process, resulting in a beautiful coating finish, as well as beautiful intermediate and top coats.

【table】

[Table] * Spreads in granular form without atomizing.

[Brief explanation of drawings]

The figure is a perspective view illustrating a part of the method to which the present invention is applied. 1...Flat steel plate, 2...L steel plate, 3...Spray gun, d...Gap, _P1 , _P2 ...Spot welding position.

Claims (1)

[Claims] 1 Mix a plasticizer and an adhesion promoter with vinyl chloride resin, vinyl chloride copolymer resin, or a blend resin of these resins to reduce the kinematic viscosity to 2000 cps or less.
A method for applying a body sealer, which comprises spraying a sealer whose static viscosity is adjusted to 15,000 to 70,000 cps into a gap to fill the gap.