JPH0331754B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention relates to a vinyl chloride plastisol sealer that has almost no flow at room temperature due to the working conditions of the sealer process, and is designed to improve the sealing effect by causing flow during heat curing. . [Prior Art] Vinyl chloride plastisol sealers that have been commonly used for vehicles are known to have flow properties and those with almost no flow properties, depending on the application conditions. Those with the above-mentioned flow properties are JIS
In the fluidity test of K6830-13 (2), when tested using a 10φ semicircular beat, the
mm/10 minutes (horizontal), 20-200 mm/10 minutes (vertical)
At 140℃, 10~100mm/5 minutes (horizontal), 10~100mm/5 minutes (horizontal)
Flow properties of 200mm/5 minutes (vertical) are shown. Similarly, those without flow properties exhibit flow properties of 10 mm or less/30 minutes both horizontally and vertically at room temperature. [Problem to be solved by the invention] However, when a sealer with flow properties is applied to a sloped area and left at room temperature for a long time, most of the applied sealer will run off and the sealing effect will be significantly reduced. It is reduced and becomes difficult to use. In addition, if the above sealer with no flow properties is applied to a nearly horizontal area, the covering effect of the steel plate joints will be significantly inferior, and in some cases, brushing, etc.
Correction with a spatula is required. That is, all of the conventionally known sealers have been subject to limitations in terms of application locations and conditions of use. These drawbacks are due to the fact that they do not have the characteristics of eliminating flowability at room temperature, making them easy to handle, and also causing flow when heated and then curing. SUMMARY OF THE INVENTION An object of the present invention is to provide an extremely ideal sealer that eliminates all of the conventional drawbacks and has almost no flowability at room temperature, but exhibits flowability in the early stages of heating. [Means for Solving the Problems] The object of the present invention is achieved by blending a temperature-sensitive thixotropic agent into a base resin of vinyl chloride resin and its copolymer. This invention will be explained in detail below. First, the temperature-sensitive thixotropic agent referred to in this invention is a compounding component that is added to a sealer that is formed so as not to exhibit flowability at room temperature in order to impart flowability only when heated. Specifically, hydrogenated oils such as hydrogenated linseed oil and hydrogenated castor oil, and low-melting polyethylene, etc.
It is a thermoplastic resin with a melting point of 100℃ and high oil absorption. These thermoplastic resins may be blended alone into the base resin, or may be used in combination with conventional thixotropic agents. This hydrogenated linseed oil has a melting point of 69-71℃, hydrogenated castor oil has a melting point of 86-90℃, and low-melting polyethylene has a melting point of about 100℃.All of these resins are powder-like and have a large oil absorption capacity at room temperature. . The blending ratio of these temperature-sensitive thixotropic agents may be 0.1 to 10 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the total sealer.
Weight%. Next, the base resin of the sealer of the present invention refers to a vinyl chloride resin and a copolymer thereof having an average degree of polymerization of about 500 to 3,000. The blending ratio of this base resin is 10 to 50% by weight, preferably 15 to 30% by weight, based on 100 parts by weight of the total sealer. In the sealer of the present invention, fillers such as calcium carbonate, talc, zinc white, titanium oxide, clay, kaolin, silica, and alumina are optionally used in an amount of 20 to 60% by weight based on 100 parts by weight of the sealer. As the plasticizer, phthalate esters such as di-2-ethylhexyl phthalate (DOP) and diisononyl phthalate (DIDP) are preferable, and di-2-ethylhexyl adipate (DOA) and butyl phthalyl butyl glycolate (BPBG) are preferable. , di-2-ethylhexyl azelaate (DOZ), di-2 sebacate
-Ethylhexyl (DOS) etc., adipic acid type,
Polyester plasticizers such as trimellitic acid type and phthalic acid type can also be used. These plasticizers are used in an amount of 5 to 50% by weight based on 100 parts by weight of the total sealer. As for other additives, by using 0.1 to 30 parts by weight of well-known thixotropic agents in 100 parts by weight of the total sealer, it is possible to increase or decrease the amount of flow during heating. Any of silicic acid, silicic anhydride, organic bentonite, and ultrafine particles of calcium carbonate can be used. As the adhesion promoter, any of the well-known acrylic, amine, and imine adhesives can be preferably used, and the blending ratio is 0.1 to 100 parts by weight of the total sealer.
It is preferably about 10% by weight. In addition, when stability of the sealer is particularly required, a stabilizer may be appropriately used. Specific examples of these stabilizers are metal salts such as Pb, Ba, Zn, Sn, Ca, etc. Furthermore, the flow characteristics of the present invention can be easily adjusted by changing the type or amount of the above-mentioned compounding agents. [Action of the Invention] The heat-flowable vinyl chloride plastisol sealer of the present invention has an excellent sealing effect. Although the mechanism by which the heat-flowable vinyl chloride plastisol sealer exhibits such excellent sealing effects is not yet clear,
It can be considered as follows. That is, the temperature-sensitive thixotropy imparting agent has a large oil absorption capacity, and when the composition is blended and kneaded, liquid components are taken into the material, so-called structural viscosity is formed, and it does not have fluidity at room temperature. However, when heated in a drying oven, etc., this temperature-sensitive thixotropy agent melts at around its melting point of 69 to 100°C, destroying its structural viscosity, resulting in an immediate decrease in the viscosity of the PVC sol, making it difficult to flow. The heat flow properties shown in Table 2 are shown. Then, heating continues and when the melting temperature of the vinyl chloride resin reaches 110 to 120°C, the sealer begins to gel, loses fluidity, and stops flowing. Due to this behavior, during the assembly process of automobiles, etc., after the heat-flowable vinyl chloride plastisol sealer is applied until it is transferred to the drying oven, or while it is left in the process, it may flow and drip. Therefore, it is possible to provide a vinyl chloride plastisol sealer which has an excellent sealing effect and quickly flows and gels when it enters a drying oven. [Example] Examples 1 to 4, Comparative Examples 1 and 2

[Table] Vinyl chloride plastisol sealer compositions used in Examples and Comparative Examples are prepared by mixing the following substances. ●Vinyl chloride paste resin "G-121" manufactured by Nippon Zeon Co., Ltd. Straight type resin for vinyl chloride paste Average degree of polymerization: 1650 ●Filler "NS-100" manufactured by Nitto Funka Co., Ltd. Untreated heavy calcium carbonate Average Particle size: 1.5 μm ●Plasticizer “DOP” manufactured by Kyowa Hakko Co., Ltd. Molecular weight: 391 ●Thixotropic agent “Neolite SP” manufactured by Takehara Chemical Co., Ltd. Fatty acid-treated colloidal calcium carbonate Average particle size: 0.08 μm “Hakuenka CCR” Manufactured by Shiraishi Calcium Co., Ltd. Surface treated ultra-fine calcium carbonate Average particle size: 0.08 μm "Aerosil 380" manufactured by Nippon Aerosil Co., Ltd. Colloidal silica Surface area: 380 m ² /g ●Castor oil "Disparon 305" manufactured by Kusumoto Kasei Co., Ltd. Melting point ;88℃ ●Hydrogenated linseed oil (Note) Produced using the following synthesis method. Put 500g of linseed oil and 1g of Raney nickel in a flask and raise the temperature to 180℃ while stirring.
Next, hydrogen was gradually added and the reaction was carried out at 2.5 atmospheres for 2 hours. Take it out, cool it, and crush it. Melting point: 70
Obtain hydrogenated linseed oil at °C. ●Low-temperature melting polyethylene "UM-3220" manufactured by Ube Industries, Ltd. Low-density powder polyethylene Molecular weight: 20000-30000 ●Amine-based adhesion promoter "Tomide 235A" manufactured by Fuji Kasei Co., Ltd. Amine value: 360±20 ●Stabilizer "Tribase" manufactured by Sakai Kasei Co., Ltd. Tribasic lead sulfite The above substances were kneaded for 1.5 hours using a kneader equipped with a pressure reduction device according to the composition ratio shown in Table 1, and then degassed and stirred in the kneader for 2 hours. and discharged from the kneader to obtain six types of sealers. The sealers obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were tested according to JIS K6830.
The results are listed in Table 2 below. Note that the steel plate used in this test was subjected to cationic electrodeposition in advance.

[Table] As is clear from Table 2, the product of this example shows almost no flowability at room temperature, but has the property of flowing and post-curing when heated. When the Example product was applied to an inclined automobile door hemming part and a horizontal part and cured, it could be used very suitably. In addition, the sealer obtained in Comparative Example 1 can be used on sloped parts such as door hemming parts of automobiles, but
The sealing effect on the applicable area is poor, and the accuracy of the work is extremely required. Furthermore, the covering effect is significantly poorer in horizontal areas. In Comparative Example 2, the sealer could be used on horizontal areas, but could not be used on sloping areas such as the hemming part of the door. [Effects of the Invention] As detailed above, the heat-flowable vinyl chloride plastisol sealer of the present invention has a melting point of 69 to 100.
Contains 0.1 to 5% by weight of a temperature-sensitive thixotropic agent consisting of hydrogenated linseed oil, hydrogenated castor oil, and low-melting polyethylene at a temperature of 0.1 to 5% by weight. It exhibits fluidity and penetrates into the gaps, allowing it to exhibit good rust prevention properties. Therefore, the sealer of the present invention is extremely suitable for use in vehicles.

Claims (1)

[Claims] 1 Average degree of polymerization when the whole is 100% by weight
500-3000% vinyl chloride resin and its copolymer resin 15-30% by weight and a melting point of
0.1-5% by weight of a temperature-sensitive thixotropic agent consisting of one or more of hydrogenated linseed oil, hydrogenated castor oil, and low-melting polyethylene at 69-100°C, and a plasticizer 15
Contains ~30% by weight, 0.1-2% by weight of adhesion promoter, 40-60% by weight of filler, and 0-2% by weight of thixotropic agent, and has a flat flow property at room temperature for 30 minutes. , both vertically 10 mm or less, and 140
Flow properties at °C are 10 to 50 mm horizontally and 50 to 50 mm vertically.
A heat-flowable vinyl chloride plastisol sealer characterized by a diameter of 200 mm.