JPH0145506B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a highly permeable sealant composition, particularly a vinyl chloride resin sealant composition that has high permeability into narrow areas such as gaps between metal plate joints. Conventionally, as sealants for sealing joints formed by spot welding of sheet metal parts of automobile bodies, for example, there are vinyl chloride plastisol-based sealants whose main component is paste-like vinyl chloride resin, and other sealants. Depending on the working conditions, those with a viscosity of 20,000 to 150,000 cps (20°C) are used, and depending on the application conditions, fluid or non-flowable materials are used. To seal the seams described above using such a sealant, use a coating machine such as a sealing gun to apply a bead to the steel plate joint, and then use a brush or rubber spatula to fill the gaps between the seams. This is done by removing excess sealant at the same time as rubbing it in, then spraying the paint, and gelling or curing the paint film when it is baked in a baking oven. However, with such sealants,
As shown in FIG. 1, the sealant 5 has poor permeability into the gap 4 of the seam 3 between the steel plates 1 and 2, and only adheres to the surface of the seam 3 of the steel plates.
When removing excess sealant 5 with a spatula or the like, the thickness of the coating film may become extremely thin, or if the application is done in a complicated manner, defects may occur where no sealant remains. In such a case, water may leak from outside the vehicle body, or the steel plate may rust due to this. In order to prevent such water leakage, it is necessary to sufficiently infiltrate the gap between the steel plate joints with the sealing agent so as to sufficiently fill the gap. For this purpose, low filler formulation,
Low clay due to high plasticizer formulation and high leveling formulation.
It is necessary to use a high-leveling sealant. However, if the viscosity of the sealant made by the above method is less than 15,000 (at 20°C), it will show permeability of 8 mm or more even when there is no gap between overlapped parts, but the fluidity will be 50 to 150 mm at all times and in 30 minutes at 140°C. However, the sealant sag occurs during work or during the post-process painting process, making it difficult to put it into practical use. The present invention was made by focusing on the problems of conventional sealants as described above, and includes 100 to 200 parts by weight of plasticizer to 100 parts by weight of vinyl chloride polymer.
100 to 400 parts by weight of filler, 0.1 to 20 parts by weight of adhesion promoter, 0.1 to 10 parts by weight of stabilizer and 1 to 100 parts of blocked isocyanate prepolymer as permeability agent.
Consisting of 20 parts by weight, viscosity at 20℃ is 15,000~
The present invention aims to solve the above problems with a highly permeable sealant composition having a pressure of 30,000 cp and a fluidity of 10 mm or less. The base range of the sealant composition according to the invention is an average degree of polymerization of 500 to 3000, preferably
500-1500 vinyl chloride polymer. In addition to vinyl chloride homopolymers, such vinyl chloride polymers may also be copolymers with up to 20 mol% of other copolymerizable monomers, and these are usually in the form of vinyl chloride paste resin. used in Copolymerizable monomers for vinyl chloride include vinylidene chloride, vinyl bromide, vinyl fluoride, vinyl acetate, styrene, vinyltoluene, vinylpyridine, alkyl acrylate, (for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n -butyl acrylate, etc.), acrylic acid,
Examples include methacrylic acid, alkyl methacrylates (eg, methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, etc.), acrylonitrile, methacrylototrile, and the like. As the plasticizer, any plasticizer that is normally used for vinyl chloride resin can be used, such as dibutyl phthalate, dihexyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate (hereinafter referred to as DOP), - Phthalate esters such as n-octyl phthalate, diisooctyl phthalate, dinonyl phthalate, butylbenzyl phthalate, trimellitic acid esters such as tributyl trimellitate, trioctyl trimellitate, dioctyl adipate, dioctyl azelate, dioctyl Aliphatic polybasic acid esters such as sebacate, phosphate esters such as tricresyl phosphate, tricylenyl phosphate, monooctyl diphenyl phosphate, trioctyl phosphate, tributylacetyl citrate, trioctyl acetyl citrate,
Citric acid esters such as tributyl citrate,
Examples include epoxidized animal and vegetable oils such as epoxidized soybean oil and epoxidized linseed oil. Among these, alkyl esters of aromatic or aliphatic polycarboxylic acids are preferred, and phthalate esters are particularly preferred. These plasticizers are used in an amount of 100 to 200 parts by weight, preferably 130 parts by weight, per 100 parts by weight of vinyl chloride polymer.
~160 parts by weight is blended. Examples of the filler include calcium carbonate, talc, titanium oxide, clay, and silica, with calcium carbonate being preferred. These fillers are blended in an amount of 100 to 400 parts by weight, preferably 150 to 350 parts by weight, per 100 parts by weight of the vinyl chloride polymer. Examples of adhesives include acrylic resins, epoxy resins, and amine resins. Examples of acrylic resins include alkyl methacrylates such as methyl acrylate, ethyl acrylate, isopropyl acrylate, and butyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and butyl acrylate; acrylic acid, methacrylic acid, acrylonitrile, and methacrylate; There are homopolymers of acrylic monomers such as lonitrile, acrylamide, methacrylamide, copolymers of these with each other, or copolymers of the acrylic monomers with other copolymerizable monomers, etc. 0.1 to 20 parts by weight, preferably 5 parts by weight per 100 parts by weight of vinyl chloride polymer
~20 parts by weight is blended. Examples of epoxy resins include epichlorohydrin-bisphenol A-type epoxy resins, polyhydric alcohol-epichlorohydrin-type epoxy resins, organic acid-epichlorohydrin-type epoxy resins, and epoxidized animal and vegetable oils. Most preferably, these epoxy resins are used in an amount of 0.1 to 20 parts by weight per 100 parts by weight of vinyl chloride polymer.
It is blended in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight.
Examples of the amine resin include polyamide, melamine resin, benzoguanamine resin, etc., but polyamide with an amine value of 200 to 400 is preferred, and these amine resins are used in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the vinyl chloride polymer. , preferably 0.1 to 10 parts by weight. As the stabilizer, any stabilizer commonly used for vinyl chloride resins can be used. For example, lead, cadmium, barium,
Metal combinations of zinc, calcium, etc. and stearic acid, lauric acid, ricinoleic acid, naphthenic acid, 2-ethylhexoic acid, etc., and organic tin compounds such as dibutyltin dilaurylate, dibutyltin dimaleate, dibutyltin dimercaptide, etc. are preferred. It is an organic tin compound. These stabilizers are
It is blended in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the vinyl chloride polymer. The blocked isocyanate prepolymer used as the permeability imparting agent is one obtained by reacting an isocyanate compound and a predetermined amount of blocking agent in an inert solvent at a temperature of room temperature to 160°C with the addition of a catalyst if necessary. There are various types depending on the type of isocyanate compound and blocking agent used, but they are classified according to the blocking agent commonly used. Such blocking agents include, for example, phenol, cresol, xylenol, p
-ethylphenol, o-, isopropylphenol, p-tert-butylphenol, p-tert-
Phenols such as octylphenol, thymol, p-naphthol, p-nitrophenol, p-chlorophenol, methanol, ethanol,
Alcohols such as propanol, butanol, ethylene glycol, methyl cellosolve, butyl cellosolve, methyl carbitol, benzyl alcohol, phenyl cellosolve, furifuryl alcohol, cyclohexanol, activated methylene such as malonic acid, dimethyl, diethyl malonate, ethyl acetate, etc. mercaptans such as butyl mercaptan, thiophenol, and tert-dodecyl mercaptan; acid amide systems such as acetanilide, acetanisidide, acetate amide, and benzamide; imide systems such as succinimide and maleic imide; diphenylamine, phenylnaphthylamine, and aniline. , amine type such as carbazole, imidazole,
Imidazole type such as 2-ethylimidazole, urea type such as urea, thiourea, ethylene urea, carbamate type such as phenyl phenylcarbamate, 2-oxazoline, imine type such as ethylene imine, propylene imine, formaldoxime , oxime series such as acetaldoxime, methyl ethyl ketoxime, cyclohexanone oxime,
There are sulfite-based salts such as sodium bisulfite and potassium bisulfite, and amine-based ones are preferable. These blocked isocyanate prepolymers are used in an amount of 1 part by weight per 100 parts by weight of vinyl chloride polymer.
~20 parts by weight, preferably 1 to 10 parts by weight. The highly permeable sealant composition according to the present invention comprises:
It is obtained by thoroughly kneading the above components using a kneader, extruder, roll, etc., and its viscosity at 20°C is 15,000 to 30,000 cp.
and the fluidity is within 10mm. In addition, "fluidity" as used in this specification refers to a 70-degree angle formed by applying a semicircular sealing agent composition 3 mm in height and 10 mm in width onto a steel plate coated with cationic or anionic electrodeposition. This refers to the distance that the sealant composition drips after being held at room temperature for 10 minutes and at 140°C for 30 minutes. Also, “permeability”
This means that two steel plates coated with cationic or anionic electrodeposition are stacked together, a sealant composition is applied to the joint, held horizontally and at an angle of 70° at room temperature for 10 minutes, and then held at 140°C for 30 minutes. This refers to the distance that the sealant composition penetrates when two steel plates are peeled off after cooling. The sealant composition of the present invention having the above configuration is used, for example, in the following manner. That is, using a sealing gun (not shown), the sealant composition was discharged in a bead shape onto the seams 13 (for example, spot welding locations) of metal plates 11 and 12 such as steel plates, as shown in FIG. 2A. Afterwards, using a brush, spatula, etc. (not shown),
The sealing of the gap 14 is completed by correcting the gap 14 as shown in FIG. Since the sealant composition according to the present invention has the above-mentioned physical properties, it can be used for sealing various parts, but it is particularly suitable for sealing gaps in spot welding parts of automobile bodies, for example, as shown in Fig. 3. , roof drip rail 15, trunk opening 16, rear combination lamp 17, floor 18
Used to seal gaps in areas such as 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, a sealant composition is applied to the sealing area having the above-mentioned gap using a sealing gun, and after correction, baking is performed at, for example, 120 to 170 for 5 to 20 minutes, preferably 130 to Temporarily bake the sealant at 150℃ for 15 to 20 minutes. Then, if necessary, after performing intermediate painting by spray painting, etc.,
After baking for ~40 minutes and then applying a top coat using spray painting, etc.
By baking for 40 minutes, the car body is painted and the sealing parts are completed at the same time. Next, the present invention will be explained in more detail by giving Examples. Examples 1 to 2 and Comparative Examples 1 to 4 Vinyl chloride paste resin (degree of polymerization 1650) (Zeon 121, manufactured by Nippon Zeon Co., Ltd.), calcium carbonate (Whiten SB, Shiraishi Calcium Co., Ltd.) in the proportions shown in Table 1 ), (C ₄ H ₉ ) ₂ Sn(SRCOOR′) ₂
[However, in the formula, R is an alkyl group having 3 or less carbon atoms,
R' represents an alkyl group having 8 to 12 carbon atoms. ] Dibutyltin mercaptide (StanciereT−
86, manufactured by Dainippon Ink Chemical Co., Ltd.), polyamide amine (polymer consisting of an unsaturated fatty acid with 18 carbon atoms, linoleic acid dimer, and alkylene polyamine, amine value approximately 240) (Versamide 115, manufactured by Henkel Japan Co., Ltd.) , blocked isocyanate prepolymer (A) (amine-based blocked isocyanate
Neolets U-314 manufactured by Polyvinylchemie), blocked isocyanate prepolymer (B) (phenol blocked isocyanate, manufactured by Sumitomo Bayer Urethane Co., Ltd., Desmodyur BL-1100), carbon number 2
~12 aliphatic polybasic acids, aliphatic polyhydric alcohols having 2 to 12 carbon atoms, and polyester polyols (molecular weight approximately 2200) consisting of alkylene oxides having 2 to 4 carbon atoms (Paraplex G50, manufactured by Rohm and Herrs); and After kneading a compound consisting of di-2-ethylhexyphthalate (DOP) with a kneader, defoaming stirring was performed for 60 minutes.
Various sealant compositions were prepared.

[Table] The sealant composition obtained in this way
The test was conducted in accordance with JIS K6830, and the results shown in Table 2 were obtained. Further, as shown in Fig. 3, 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 drip rail, trunk opening, rear combination lamp, floor, etc. The sealant composition was applied to the diameter gap using a sealing gun in the shape of a bead with a diameter of about 3 mm, a part of which was brushed, 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. The sagging and permeability during the operation were as shown in Table 2.

[Table] As is clear from Table 2, in Comparative Example 1, the viscosity
At 40,000 cp, the permeability is 0 to 1 mm and the fluidity is 1 mm, so it hardly penetrates into the gaps between the steel plate joints.
In Comparative Example 2, the viscosity was 11000 cp and the permeability was 8 mm or more, but the fluidity was 45 mm, which caused problems in work. In Comparative Example 3, the permeability was 3 to 4 mm and the fluidity was 19 mm at 19,000 cp per year, and although the permeability was improved, the fluidity was increased. In Comparative Example 3, a commonly used polyester leveling agent was added, and the permeability was 5 mm or more, but the fluidity was extremely high, especially at 26 mm at 140°C for 30 minutes. It is expected that work will sag. On the other hand, the sealant composition according to the present invention has a viscosity of 15,000 to 30,000 cp (at 20°C) and is made of vinyl chloride resin platisol containing a blocked isocyanate prepolymer as a permeability imparting agent. Both the properties and permeability are appropriate, and sufficient permeability can be obtained without impairing workability. As described above, the present invention includes 100 to 200 parts by weight of a plasticizer, 100 to 400 parts by weight of a filler, 0.1 to 20 parts by weight of an adhesion promoter, based on 100 parts by weight of a vinyl chloride polymer.
It consists of 0.1 to 10 parts by weight of a stabilizer and 1 to 20 parts by weight of a blocked isocyanate prepolymer as a permeability imparting agent, and has a viscosity of 15,000 to 15,000 at 20°C.
30,000 cp and has a fluidity of 10 mm or less, it is a highly permeable sealant composition, so it has appropriate permeability and fluidity, so when sealing the seam gap, the sealant composition It is possible to improve the permeability into the gap between the steel plate joints without deteriorating the workability of the steel plate, and it is possible to prevent water leakage due to coating defects as in the conventional method.
Further, the above effect is particularly great when an amine type is used as the blocked isocyanate prepolymer. Therefore, the above-mentioned sealant composition is extremely effective for parts such as automobile bodies, which have many spot welded parts and it is important to seal the seam gaps.Especially if sealing is performed after electrodeposition coating Since it can be hardened in the baking process of the subsequent intermediate painting and top coating, workability and economical efficiency are improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a state in which a conventional sealant composition is applied to a steel plate joint, FIG. 2A is a perspective view showing a state in which a sealant composition according to the present invention is applied with a sealing gun, and FIG. 2B 3 is a perspective view showing a modified state of the sealant composition, and FIG. 3 is a schematic perspective view showing a portion of an automobile body to which the sealant composition is to be used. 11, 12... Steel plate, 13... Seam, 14...
Gap, 15... Sealant composition.

Claims (1)

[Claims] 1 Vinyl chloride polymer 100 with an average degree of polymerization of 500 to 3000
Plasticizer for vinyl chloride polymer 100 to parts by weight
200 parts by weight, 100-400 parts by weight of powdered inorganic filler,
0.1 to 20 parts by weight of at least one adhesion promoter selected from the group consisting of acrylic resins, epoxy resins and amino resins, and 0.1 parts by weight of a stabilizer for vinyl chloride polymers.
~10 parts by weight and 1 to 20 parts by weight of a permeability imparting agent made of a blocked isocyanate prepolymer, and has a viscosity of 15,000 to 30,000 cp at 20°C,
A highly permeable sealant composition with fluidity within 10 mm.