JPH08907B2 - Sealant for automatic application - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride plastisol sealing material used as a sealing material for a steel sheet joining portion of an automobile. The sealing material of the present invention is useful for automatic application by a robot or the like.

[0002]

2. Description of the Related Art Vinyl chloride plastisol is used as a sealing material in a steel sheet joining portion of an automobile.
By the way, in order to apply the sealing material, there is known a method of manually applying the sealing material while discharging the sealing material from a spray gun. However, the manual coating method has a problem that it is difficult to obtain stable coating quality because of large variations due to individual differences. Therefore, automatic application by robots is being considered. However, in the case of automatic coating, there is a problem that it is difficult to obtain stable quality when the discharge amount is changed. Therefore, the applicants of the present application have filed Japanese Patent Application Laid-Open Nos. 62-246981 and 6
Japanese Unexamined Patent Publication No. 2246982 discloses a sealing material in which the viscosity of the sealing material is appropriately defined and stable coating quality can be obtained even when the discharge amount is changed.

[0003]

In a sealing material spray-applied by hand, there is a problem that the spray pattern fluctuates due to temperature fluctuations, etc., even though the sealing material is applied with a constant discharge amount. there were. This is due to a large change in viscosity of the sealing material in the high shear rate region during spraying. To solve this problem, simply lower the viscosity of the sealing material. This is because the lower the viscosity, the smaller the change in viscosity with respect to temperature changes. However, simply lowering the viscosity also lowers the viscosity in the low shear rate region, causing problems such as sagging.

The present invention has been made in view of such circumstances, and although the viscosity can be maintained to some extent in the low shear rate region, the viscosity in the high shear rate region is low, and the viscosity against the temperature fluctuation is high. The purpose is to reduce the change.

[0005]

As a result of various investigations in view of the above problems, the present inventors set the kinematic viscosity in the high shear rate region and the static viscosity in the low shear rate region within the optimum range at each temperature. The present invention has been completed by finding that the above-mentioned problems can be solved by the above. That is, the sealing material for automatic coating of the present invention is a sealing material coated with a spray using a vinyl chloride resin and a plasticizer as a base material, and a vinyl chloride resin having a particle size distribution of 0.2 to 50 μm. % By weight, 20-35% by weight of fine particle calcium carbonate, and 5-10% by weight of a viscosity reducing agent, and the kinematic viscosity at 20 ° C. at a shear rate of 9400 sec ⁻¹ is 500-1000 cps and at 20 ° C. The ratio of the kinematic viscosity to the kinematic viscosity at 35 ° C. is 1.5 or less, and the static viscosity at 20 ° C. at a shear rate of 4 sec ⁻¹ is 50000 cps or more.

[0006] Sealing material of the invention Ri vinyl chloride plastisol der, the vinyl chloride-based resin, polyvinyl chloride or polymer chain in a copolymer material having a vinyl chloride groups,
Examples thereof include copolymers of vinyl chloride and vinyl acetate, vinylidene chloride, acrylic acid ester, maleic anhydride or maleic acid. Alternatively, these blend polymers can be used.

In the present invention, the vinyl chloride resin is added with
Those having a particle size distribution of 2 to 50 μm are used. By having such a wide particle size distribution, it is possible to have viscosity characteristics as described below. The vinyl chloride resin is contained in the sealing material in an amount of 5 to 25% by weight.
As the plasticizer, for example, phthalic acid, adipic acid-based polyester, trimellitic acid, and pyromellitic acid-based polyester are known. The plasticizer may be added in an amount of about 20 to 40% by weight based on the whole sealing material.

The sealing material of the present invention contains fine particle calcium carbonate. The fine particle calcium carbonate refers to one having an average particle diameter of around 0.07 μm, and the fine particle calcium carbonate is 20 in the sealing material of the present invention.
˜35% by weight. This fine particle calcium carbonate imparts an appropriate thixotropy, and can prevent sagging in a low shear rate region.

Further, the sealing material of the present invention contains a viscosity reducing agent such as a petroleum high boiling point solvent in an amount of 5 to 10% by weight. This thinning agent has the function of lowering the kinematic viscosity in the high shear rate region. In addition, other additives such as powder fillers such as calcium carbonate, clay, talc, and silica, adhesion promoters such as amine compounds, heat stabilizers composed of organic acid salts of metals such as barium, zinc, tin, lead, and calcium. Can be used in a conventional manner.

With the above composition, the sealing material of the present invention exhibits a peculiar viscosity behavior as follows. That is, 2 when the shear rate is 9400 sec ^-1
The kinematic viscosity at 0 ° C. is 500 to 1000 cps.
Therefore, the viscosity during spraying is low even at low temperatures.
This can prevent the spray pattern from changing. Furthermore, the static viscosity at 20 ° C. at a shear rate of 4 sec ⁻¹ is 50000 cps or more. This prevents dripping after application.

The greatest feature of the present invention is that the ratio of the kinematic viscosity at 20 ° C. to the kinematic viscosity at 35 ° C. is 1.5 or less. As a result, the fluctuation of the viscosity with respect to the fluctuation of the temperature is small, and the fluctuation of the spray pattern can be further prevented.

[0012]

With the sealing material for automatic coating of the present invention, the viscosity in the high shear rate region is low, and the fluctuation of the kinematic viscosity due to temperature fluctuation is small. Therefore, the variation of the spray pattern with respect to the variation of the discharge amount and the variation of the temperature becomes small, and stable coating can be performed. In addition, the static viscosity in the low shear rate region is extremely high, and drooping is prevented.

That is, according to the sealing material of the present invention,
The variation of the spray pattern with respect to the temperature variation is small, and the variation of the spray pattern with respect to the variation of the discharge amount is small. Therefore, even if the temperature or discharge amount changes, it is possible to apply with a stable spray pattern,
The coating quality is improved. In addition, sagging after application is prevented. Due to these effects, the sealing material of the present invention is most suitable for automatic application.

[0014]

Embodiments will be specifically described below with reference to embodiments. Example 1 Secondary aggregation type vinyl chloride resin (particle size 0.2 to 50 μm)
m) 14 parts by weight, general-purpose type B vinyl chloride resin (“Zeon 51” manufactured by Nippon Zeon Co., Ltd., average particle size 40 μm)
m), 12 parts by weight, fine particle calcium carbonate powder having an average particle diameter of 0.07 μm (“Neolite SP” Takehara Chemical Co., Ltd.)
28 parts by weight, 8 parts by weight of a thinning agent, DO as a plasticizer
P26 parts by weight and 12 parts by weight of other additives such as an adhesion-imparting agent were mixed with a disper to obtain a sealing material of this example.

This sealing material has a shear rate of 9400 s.
the viscosity at 20 ° C. in ec ⁻¹ is 750 cps,
The viscosity at 20 ° C. at a shear rate of 4 sec ⁻¹ is 8500.
It is 0 cps. The kinematic viscosity at a shear rate of 9400 sec ^-1 was measured with a capillary extrusion viscometer and the shear rate was 4 sec.
^{-1 The} static viscosity was measured with a B type viscometer. The kinematic viscosity at 35 ° C was measured and the ratio to the kinematic viscosity at 20 ° C was
It is 1.48 .

This sealing material was pressurized by a coating device (plunger type constant supply pump with an initial coating control function) and discharged from a nozzle tip to measure the spray pattern coating width at 20 ° C and 35 ° C. . Of course, at a high temperature of 35 ° C., the spray pattern spreads, and the difference was 8 mm, which was extremely small compared to the conventional case. In addition, the dropping property of this sealing material was evaluated. The drooping property was measured by applying a sealing material in the shape of a semicircular bead having a diameter of 10 mm and scraping it off with a spatula without scraping it from the spatula. And, when it does not droop over 150 mm or more, it is ○, 100 mm to 150 m
The case where it drooped in less than m was evaluated as Δ, and the case where it drooped in less than 100 mm was evaluated as x. As a result, the sealing material of this example did not droop even when scratched by 150 mm or more, and was extremely excellent in drooping property. (Examples 2 to 5 and Comparative Examples 1 to 5) Each sealing material was prepared with the composition shown in Table 1, and the viscosity and temperature sensitivity (20 ° C. and 35 ° C.) were the same as in Example 1.
The ratio of kinematic viscosity in the above), variation in coating width, and sagability were measured. The results are shown in Table 1. As the general-purpose type A vinyl chloride resin, "Zeon 121" (manufactured by Nippon Zeon Co., Ltd., average particle size: 1 to 2 µm) was used, and the calcium carbonate powder was "N".
CC # 45 "(manufactured by Nitto Koka Co., Ltd.) was used.

[0017]

[Table 1]

(Evaluation) The sealing material of Comparative Example 1 has a narrow particle size distribution of the vinyl chloride resin, a relatively large amount of the filler, and does not contain a thinning agent, and therefore has a high kinematic viscosity at 20 ° C. ing. Therefore, the temperature sensitivity is also high, and the variation of the coating width is 15 mm, which is about twice that of Example 1. Therefore, in Comparative Example 2 in which the amount of calcium carbonate was decreased and the amount of plasticizer was increased, the kinematic viscosity decreased by 500 cps, but at 20 ° C.
The static viscosity at 1 is extremely reduced, causing dripping.

In Comparative Examples 3 and 4, the amount of the vinyl chloride resin is large and the kinematic viscosity is slightly high, so that the temperature sensitivity is high. In the sealing material of Comparative Example 4, the temperature sensitivity is in an appropriate range, but the static viscosity at 20 ° C. is low and sagging occurs. Further, the sealing material of Comparative Example 5 has a small amount of finely divided calcium carbonate and does not contain a viscosity reducing agent, so that both the kinematic viscosity and the static viscosity are extremely high and spray application is difficult.

On the other hand, in the sealing material of the example, since the vinyl chloride resin, the fine particle calcium carbonate and the viscosity reducing agent are adjusted to the optimum ranges, the kinematic viscosity, the static viscosity and the temperature sensitivity are in the optimum ranges. As a result, the variation in the coating width is small and there is no sagging property. Therefore, it is most suitable for automatic application.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiro Miyajima 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor Haruji Shibata 1 Toyota Town, Aichi Prefecture, Toyota Motor Corporation ( 72) Inventor Kenji Tamura 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) Reference JP 62-246981 (JP, A) JP 62-246982 (JP, A) JP Heihei 3-162440 (JP, A) JP 62-246983 (JP, A)

Claims (1)

[Claims] 1. A sealing material, which comprises a vinyl chloride resin and a plasticizer as a base material and is applied by spraying, wherein 5 to 25% by weight of the vinyl chloride resin having a particle size distribution of 0.2 to 50 μm and fine carbon dioxide. Includes 20-35% by weight calcium and 5-10% by weight thinning agent, shear rate 940
Kinematic viscosity at 0 ° C at ⁰ sec ^-1 is 500-1
The static viscosity at 20 ° C. is 5,000 cps, the ratio of the kinematic viscosity at 20 ° C. to the kinematic viscosity at 35 ° C. is 1.5 or less, and the static viscosity at 20 ° C. at a shear rate of 4 sec ⁻¹ is
A sealing material for automatic application, which is characterized by 0 cps or more.