JPH0539397A - Vinyl chloride plastisol composition - Google Patents

Abstract

PURPOSE:To obtian the subject composition which retains adhesive strength and crack resistance and has good durability with controlled deterioration of extensibility in particular by incorporating an epoxy resin base stabilizer for vinyl chloride resin and a tackifier comprising a blocked isocyanate. CONSTITUTION:The objective vinyl chloride plastisol composition contains a vinyl chloride resin, a plasticizer, additives, and a filler, wherein the additives contain an epoxy stabilizer for vinyl chloride resin, a tackifier comprising a blocked isocyanate, and 0.3-1.0wt.% perchlorate.

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 composition which is used as a sealing material at a joint of steel plates of vehicles, tools and electric appliances.

[0002]

2. Description of the Related Art Conventionally, a vinyl chloride plastisol-based material mainly containing vinyl chloride resin has been used as a sealing material for sealing seams formed by welding sheet metal members such as automobile parts. This sealing material keeps the airtightness of the seam and keeps the steel sheet waterproof, dustproof and rustproof.

This vinyl chloride plastisol composition usually contains a vinyl chloride resin, a plasticizer and a filler, and since the plasticizer is incorporated in a large amount, it softly penetrates into a joint or the like to form a coating film. By the way, in order to improve the adhesive strength of the vinyl chloride plastisol composition to the steel sheet, there is a method of increasing the content of the vinyl chloride resin, but in this case it affects the storage stability of the composition, so it is limited. There is. In addition, there is also a method of increasing the amount of vinyl chloride resin in order to maintain the rustproof property to enhance the retention of the plasticizer, prevent migration and extraction of the plasticizer, and prevent deterioration of the elongation of the coating film.

Therefore, a vinyl chloride plastisol composition having excellent coatability and good rust resistance has a composition containing a resin component containing a copolymer of vinyl acetate and vinyl chloride as a main component and a plasticizer containing a polyester plasticizer as a main component. It is disclosed (Japanese Patent Laid-Open No. 2-255749).

[0005]

As a mechanism for reducing the rust-preventive property of the sealing coating film, the deterioration of the coating film over time causes a decrease in elongation and cracks and the like, resulting in incomplete coating and rusting. It is possible. Since the vinyl chloride resin itself of the vinyl chloride plastisol composition does not have sufficient adhesiveness to a metal, it is copolymerized or an adhesion-imparting agent is added to enhance the adhesiveness. Furthermore, due to changes over time, temperature,
To prevent deterioration such as elongation under the influence of humidity,
Various stabilizers have been added.

Particularly, a stabilizer for epoxy vinyl chloride resin which is effective for imparting crack resistance to a coating film is used, and a blocked isocyanate is used as an adhesion imparting agent. If a combination of both is baked to form a cured film, the adhesiveness and durability of the sealing coating film may not be sufficient.
The present invention has been made in view of the above circumstances, durability and particularly elongation while maintaining adhesive strength and coating film crack resistance in a system containing an epoxy resin-based vinyl chloride resin stabilizer and a block isocyanate adhesion promoter. An object is to provide a vinyl chloride plastisol composition with suppressed deterioration.

[0007]

The vinyl chloride plastisol composition of the present invention is a vinyl chloride plastisol composition containing a vinyl chloride resin, a plasticizer, an additive, and a filler. It is characterized in that it contains 0.3 to 1.0% by weight of a stabilizer for vinyl chloride resin, a block isocyanate adhesion-imparting agent and perchlorates.

This vinyl chloride plastisol composition contains an ordinary vinyl chloride resin, a plasticizer, and a filler, has an adhesion-imparting agent containing a blocked isocyanate as a main component, and an epoxy vinyl chloride stabilizer. Salt has been added.
As the vinyl chloride resin, a copolymer with vinyl acetate is mainly used. As the plasticizer, polyester-based ones such as phthalic acid dioctyl ester, phthalic acid butylbenzyl ester, phthalic acid diisodecyl ester, phthalic acid diisononyl ester, adipic acid dioctyl ester, and sebacic acid dioctyl ester are used.

As the filler, for example, calcium carbonate, talc, clay, silica, titanium oxide, etc. are used. The additives include a block isocyanate adhesion promoter, an epoxy vinyl chloride resin stabilizer, and perchlorates. The adhesion-imparting agent contains, for example, a blocked isocyanate as a main component, and an adhesive having good compatibility with vinyl chloride can be used.

As the stabilizer, an epoxy-based vinyl chloride resin stabilizer and other oxidation stabilizers, chelating agents, lead-based stabilizers, metal soaps and the like are used in combination. The above composition alone does not necessarily provide sufficient durability for rust prevention of the vinyl chloride plastisol composition. Therefore, it is necessary to further improve the adhesiveness and durability of the sealing coating film in order to further improve its rust prevention property. However, in order to maintain the adhesiveness of the vinyl chloride plastisol composition, it is preferable to use a blocked isocyanate adhesive, and an epoxy resin-based stabilizer for vinyl chloride resin is indispensable for preventing cracking of the sealing coating.

However, according to the study by the present inventors, it was found that the addition of a small amount of perchlorate to the above composition can maintain the adhesiveness and improve the durability of elongation. Therefore, the rustproof property of the sealing coating film can also be improved. Perchlorates used here include NaClO ₄ , NaClO ₃ , KClO ₄ , and KCl.
O ₃ or the like is used.

The amount of perchlorates added is 0.3 to 1.0.
% Range. If it is less than 0.3%, the effect of addition is insufficient, and if it exceeds 1.0%, an effect commensurate with the amount added cannot be obtained, which is not preferable. It is speculated that these perchlorates accelerate the dissociation of the block of the blocked isocyanate. However, it does not affect the storage stability of the composition.

[0013]

The vinyl chloride plastisol composition of the present invention contains a small amount of perchlorates. Due to the presence of this perchlorate, deterioration of elongation and deterioration of adhesive strength due to aging can be suppressed. Further, deterioration of elongation of the sealing coating film is suppressed and cracking of the coating film can be prevented. Therefore, this vinyl chloride plastisol composition can improve the rust preventive property of the seam of the steel sheet.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples. The basic composition of the vinyl chloride plastisol composition is as follows. Vinyl chloride resin (paste type) 24% by weight,
Plasticizer (Polyester W-1000, manufactured by Dainippon Ink and Chemicals, Inc.) 29% by weight, filler (calcium carbonate) 28% by weight, and adhesion promoter 5% by weight.

As shown in Table 1, the amounts of stabilizers such as epoxy vinyl chloride stabilizer, vinyl chloride deterioration inhibitor (phosphoric acid chelator No. 5, oxidation stabilizer No. 6) and perchlorate (NaClO ₄ ) are as shown in Table 1. Each was blended individually. These vinyl chloride sol-blended mixtures were mixed using a kneader with a pressure reducing device, and then defoamed to prepare a sealing composition.

Nos. 1 and 2 are examples of the present invention, and Nos. 3 to 6 are
Is a comparative example. The test conditions shown in Table 1 are as follows. Adhesive force (shear adhesive force) Based on JASO M323-77 A sealant was applied to a steel plate coated with cation electrodeposition to a thickness of 1 mm using a spacer to prepare a test plate.
The curing conditions are 120 ° C. for 30 minutes for low temperature baking and 140 ° C. for 30 minutes for high temperature baking.

In the table, Cf indicates cohesive failure and Af indicates interfacial failure. For the elongation, the strength was measured using a test plate cured at 140 ° C. for 60 minutes. The elongation deterioration rate was 16 hours at 50 ° C. and 95% RH for 16 hours, and 80 hours at 80 ° C. for 8 hours as one cycle, and the elongation rate after deterioration was measured for 15, 30, and 90 cycles, respectively, and compared with the initial elongation. Then, the change rate was obtained. In the table, the larger the negative value, the smaller the elongation and the deterioration.

[0018]

[Table 1] The coating film cracking resistance is 15 × on a steel plate that has been subjected to cationic electrodeposition coating.
Apply it on a ribbon of 120 × 3mm and apply 8 ± at 95 ± 2 ℃.
After pre-drying for 1 minute, apply topcoat paint (baked enamel or acrylic enamel) on top. And 16
After baking at 0 ± 2 ° C. for 1 hour ± 5 minutes and drying, the degree of cracking of the sealant coating film was observed.

As a result, in the case of the examples of the present invention in which the No. 1 and No. 2 perchlorates were added, the adhesive strength at low temperature curing was improved and the cohesive failure was compared with the No. 3 to No. 6 comparative examples. Has become. However, Nos. 3 to 6 indicate that interfacial peeling occurs and the adhesiveness is insufficient. Also, the deterioration rate of elongation is about -8% in Nos. 1 and 2 of the examples, whereas it is as large as -20% in Nos. 3 to 6 of the comparative examples. Therefore, by adding a small amount of perchlorate, it is possible to improve adhesiveness and suppress elongation deterioration at the same time.

Since No. 3 of the comparative example does not contain perchlorate, the adhesive strength at low temperature curing is small and the elongation deterioration is large. N
If the amount of perchlorate of o4 is 0.1%, the effect is insufficient, the adhesive strength at low temperature curing is small, and the elongation deterioration is large. When the No. 5 PVC deterioration inhibitor is added, the elongation deterioration rate is improved, but the low temperature adhesive strength is low. When the No. 6 oxidation stabilizer is added, the adhesiveness is at the same level as in the example, but the elongation deterioration rate is large. Therefore, coating film cracking occurs.

[0021]

The vinyl chloride plastisol composition of the present invention contains a small amount of perchlorates. Therefore, the adhesiveness is improved, the elongation is not deteriorated even with the aging of the coating film, and the film has crack resistance. Moreover, the addition of the perchlorates does not cause the vinyl chloride plastisol composition to deteriorate in performance such as storage stability and coating property.

Therefore, since the steel sheet joint can be covered with this sealing material for a long period of time, rust can be prevented from occurring and rust prevention can be improved.

Claims (1)

[Claims] 1. A vinyl chloride plastisol composition comprising a vinyl chloride resin, a plasticizer, an additive and a filler, wherein the additive comprises an epoxy vinyl chloride resin stabilizer and a block isocyanate adhesion promoter and A vinyl chloride plastisol composition comprising 0.3 to 1.0% by weight of perchlorates.