JPS636103B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride plastisol composition for protecting automobiles, and more particularly to a vinyl chloride plastisol composition that forms a protective film with excellent adhesion to electrodeposited coatings, water resistance, and chipping resistance, and has excellent storage stability. The present invention relates to a vinyl chloride plastisol composition (hereinafter referred to as vinyl chloride sol) for protecting automobiles. Generally, plastisol, which is a polymer of high molecular weight vinyl chloride dispersed in a plasticizer, is well known.
These plastisols may optionally contain solvents, diluents, pigments, fillers, solution resins, surfactants, and the like. Furthermore, when coating a hydrophilic metal surface with these plastisols, it is known to mix and use a phenolic adhesion promoter. On the other hand, conventionally, bituminous-based protective materials have been used as anti-corrosive materials for the underfloor and wheelhouse areas of automobiles.
It is widely used because it has excellent features such as vibration damping power and is inexpensive, but it is especially susceptible to sand and flying stones thrown up by automobiles while driving, and rock salt, whose amount has increased dramatically in recent years. In cold weather, cracks and notches occur in the coating, and as a result, rust occurs from the damaged areas, which has become a problem. In order to prevent defects caused by these gravels and flying stones, so-called "chip-resistant materials" have been developed and are now in some use. As "chipping-resistant materials," emulsion-based materials, plastisol-based materials made of vinyl chloride resin, paint-based materials such as urethane or polyester, and improved bituminous-based materials have been developed, but they all have advantages and disadvantages. It has not yet been adopted. Among these, plastisol type products made of vinyl chloride resin have begun to be used relatively widely, based on actual results in European and American cars. The PVC sol currently used to protect automobiles consists of fine particles of vinyl chloride resin, plasticizers, fillers, etc., and the adhesion agent is a phenol-formaldehyde condensate made from phenol and a formaldehyde-forming compound. Examples are known in which an accelerator is used or an adhesive vinyl chloride resin made of a copolymer of vinyl chloride-vinyl acetate or the like containing a carboxyl group and having a low degree of polymerization is blended. Furthermore, in Japanese Patent Application Laid-Open No. 54-31441, phenol prepared from 1 mole or more of phenol per 1 mole of formaldehyde is disclosed.
Examples are disclosed using adhesion promoters consisting of formaldehyde condensates and compounds that generate low molecular weight bifunctional bonding moieties upon heat, such as hexamethylenetetraamine. However, since these PVC sol for protection of automobiles are mainly applied to the underside of automobile floors, when baking them in the baking furnace of the automobile production line, hot air does not circulate sufficiently and only heats around 120 to 130 degrees Celsius. In many cases, films obtained from PVC sol containing phenolic adhesion promoters have poor adhesion to electrodeposited coatings, especially water-resistant adhesion, and are unable to achieve desired chipping resistance. Not yet. On the other hand, when a vinyl chloride copolymer resin for adhesion is blended in a large amount to satisfy adhesion properties, storage stability deteriorates, and because the blending amount is limited, it cannot fully demonstrate its function. In view of the current situation, the present inventors have arrived at the present invention as a result of intensive research, and the purpose of the present invention is to provide a protective coating for automobiles that has excellent adhesion to electrodeposited coatings, water resistance, and chipping resistance. The object of the present invention is to provide a composition capable of forming a composition. Therefore, the gist of the present invention is to provide a vinyl chloride plastisol composition for protecting automobiles, which contains a vinyl chloride resin, a liquid plasticizer, a filler, an adhesion agent, and, if necessary, a coloring agent and an organic solvent. In this case, the adhesion agent is (A) blocked isocyanate and (B) polyamide (A):(B)=1:5 to 1:
10 (equivalent ratio), and contains 1 to 30 parts by weight of the mixture per 100 parts by weight of vinyl chloride resin. The vinyl chloride resin that can be used in the present invention may be a conventionally known resin for plastisol, and has a smooth surface with an average particle size of resin particles of around 0.8μ and a Gaussian probability curve particle size distribution between 0.2 and 2μ. The main component of the resin component is vinyl chloride resin for paste obtained by emulsion polymerization with internally dense spherical particles, and optionally coarse particle vinyl chloride resin obtained by suspension polymerization with an average particle size of around 100μ. Alternatively, vinyl chloride copolymer resins such as vinyl chloride-vinyl acetate copolymers with a low degree of polymerization containing carboxyl groups may be blended, but the blending should be done so as not to cause problems during film formation or problems with storage stability. The amount should be kept below 30% by weight based on the main constituent paste resin. The liquid plasticizer may be a general plasticizer represented by DOP, such as DEP, DBP, LBP, n-
DOP, BBP, BPBG, DOA, DOZ, DOS,
Examples include TOF, DIDP, and TCP. Examples of fillers include calcium carbonate, clay, silica, calcium silicate, aluminum silicate, magnesium silicate, magnesium carbonate, barium sulfate, carbon black, asbestos, diatomaceous earth, mica powder, etc., but the typical filler is carbonate. Calcium. Quicklime or colored pigments can also be added. It is possible to add an organic solvent to the protective vinyl chloride sol of the present invention, and those to which a hydrocarbon solvent is added in an amount of up to about 10% of the total composition are included in the vinyl chloride sol of the present invention. In the present invention, the adhesive property is added to a protective PVC sol to achieve good adhesion to metal plates or painted steel plates, especially anionic or cationic electrocoated steel plates used in automobiles. The present inventors have discovered that a mixture of (A) blocked isocyanate and (B) polyamide is suitable and extremely effective as an additive. The blocked isocyanate (A) that can be used in the present invention may be obtained by reacting an isocyanate component with a blocking agent containing active hydrogen. The isocyanate component is selected from aromatic or aliphatic diisocyanates such as hexamethylene diisocyanate, diphenylmethane diisocyanate, octane methylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, phenyl diisocyanate, tetramethylene diisocyanate, methylxylylene diisocyanate, etc. Although one or more types can be used, it is particularly preferred to use tolylene diisocyanate. The content (%) of recycled isocyanate may be 4 to 15%. As blocking agents containing active hydrogen, phenols, acid amides, lactams, lower monohydric alcohols, cellosolves, caprolactams, oximes, etc. can be used, but among these, those using methyl ethyl ketoxime are preferred. The dissociation temperature of the blocking agent of the blocked isocyanate (A) that can be used in the present invention is preferably one at which a portion of the blocking agent begins to dissociate at about 100 DEG C. to 190 DEG C. 100
If the temperature is below 190°C, the storage stability will be compromised, and if it is above 190°C, the desired adhesive performance cannot be obtained. (A) The polyamide used in combination with the blocked isocyanate (B) may be a reaction product of a fatty acid dimer and a polyamine, such as Luckamide (Nippon Reichhold Chemical Co., Ltd.), Tohmide (Fuji Kasei Co., Ltd.),
Polymide (Sanyo Oil), Versamid (General
One or more types selected from the product division such as Mills) can be used. The polyamide that can be used in the present invention preferably has an amine value of 100 to 400. As the adhesion agent, a mixture of the above-mentioned (A) blocked isocyanate and (B) polyamide is essential, and the mixing ratio is (A):(B) in equivalent ratio.
=1:5 to 1:10 is essential. If the mixing ratio is (A):(B)=1:5 or less and (A) blocked isocyanate is in excess, the hardness of the obtained film is likely to be low and the chipping resistance is poor, and (A):( If B)=1:10 or more and the amount of polyamide (B) is excessive, it is not preferable because water resistance, that is, adhesion after immersion in water and chipping resistance tend to deteriorate. The mixing ratio defined in the present invention is based on the equivalent (theoretical value) mixing weight determined from the recycled NCO% of (A) blocked isocyanate and (B) the amine value of polyamide. can be obtained using the following formula. Xgr=560/42×NCO%/Amine value×Ygr However, Xgr Polyamide weight Ygr Blocked isocyanate weight In other words, the mixing ratio of polyamide as defined in the present invention is 5Xgr to 10Xgr with respect to (A) blocked isocyanate Ygr. It is something to do. The blending ratio of these adhesion agents to the protective vinyl chloride sol is 1 to 30 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the vinyl chloride resin. If it is less than 1 part by weight, it cannot provide an adhesive function, and 30
If it exceeds 1 part by weight, storage stability may be impaired, which is not preferable. The protective vinyl chloride sol of the present invention may contain other commonly used components. For example, flame retardants, stabilizers,
It can contain surfactants and the like. These protective vinyl chloride sols can be produced using a commonly used dispersion kneader. The protective vinyl chloride sol of the present invention is ideal for applying to automobiles to protect them from scratches caused by gravel, rock salt, and the like. Taking a passenger car as an example, application sites include the underside of the floor, the wheel house portion such as the inner surface of the wheel house, and the lower peripheral surface of the vehicle such as the rocker panel, outer sill portion, and front and rear apron portions. The application method is that the viscosity of the protective PVC sol is 10,000 to 10
Due to its high viscosity of 10,000 centipoise, airless spraying is usually used, but brushing, roller or spatula application can also be used for repairs or when applying to complex areas. The protective PVC sol of the present invention exhibits extremely excellent adhesion to cationic or anionic electrocoated steel sheets used in automobiles, but it also exhibits excellent adhesion to cationic or anionic electrocoated steel sheets used in automobiles. It may also be used for. Needless to say, it may be used between the electrocoated steel sheet and the intermediate coat, or between the intermediate coat and the top coat. Protective PVC sol coatings applied to automobiles usually have a substantially 20 to 30
It is heated for minutes to form a continuous vinyl coating. Heating at least 100℃ or higher and 200℃ or lower for 10 minutes or more is required. Examples are given below to provide a more detailed understanding of the present invention. It goes without saying that the present invention is not limited to the following examples. Examples and Comparative Examples The formulations shown in Table 1 below were kneaded and dispersed in a kneader to obtain a protective vinyl chloride sol. Further, Table 2 below shows the measurement results of typical characteristic values of the films obtained from each composition.

【table】

[Table] Test method Adhesion Two 25 x 150 x 0.8 mm cationic electrodeposited steel plates were used, one on top and one on top, and overlapped with a length of 25 mm. During the overlap, the area was 25 x 25 mm and the thickness was 3 mm. Using a test piece that was force-dried and baked at 130°C for 30 minutes while holding the PVC sol, the tensile speed was measured using a Schottper type tensile tester after leaving it for 24 hours.
Measure shear strength at 200mm/min. Adhesion after immersion in water is determined by immersing a test piece in water at 20°C ± 2°C for 10 days, then pulling it out to drain the water, and measuring the shear strength after leaving it for 3 hours. Chipping resistance: Using a 0.8 x 100 x 200 mm cationic electrodeposited steel plate, apply PVC sol to a dry film thickness of 500 μm.
It was applied to a thickness of 1000μ and baked at 130°C for 30 minutes. Test after leaving for 24 hours. The test used the "Nut Drop Method" in JASO7006. A PVC pipe with an inner diameter of 20 mm and a length of 2000 mm is fixed vertically, and the test plate is fixed so that the coated surface of the test plate touches one end of the lower end of the PVC pipe and the support angle is 60°. From the top of the pipe
A brass hexagonal nut of Type 3 M-4 shape specified in JIS B1181 was dropped, and the weight of the nut was evaluated by the weight of the nut until the base material was exposed. The chipping resistance after immersion in water was measured at 20±2℃.
After immersing it in water for 10 days, take it out to drain the water, and leave it for 5 hours before testing. Viscosity measurement method Using a rotating concentric cylinder viscometer [B type viscometer BH type manufactured by Tokyo Keiki Seisakusho], the sample PVC sol was placed in a cylinder with an inner diameter of 70 m/m and a depth of approximately 100 m/m. The sample was collected at a distance of about 75 m/m from the bottom and kept in a constant temperature room at 25°C for about a day together with the viscometer. After confirming that the sample temperature was maintained at 25℃ using a mercury thermometer, the sample was manually stirred with a stirring rod for about 30 seconds, and then the No. 7 rotor was immersed in the center of the sample up to the designated marking line. , start viscosity measurement at 20 revolutions. The indicated value is read 60 seconds after the rotor is rotated, and is expressed as viscosity (poise), which is calculated by multiplying by a prescribed conversion rate. For storage stability testing, the container containing the sample is sealed,
After keeping it in a thermostat at 45°C ± 2°C for 10 days, the viscosity (poise) was determined by the same procedure as above. As a result of the above, the vinyl chloride plastisol composition for protecting automobiles according to the present invention has extremely excellent adhesion and chipping resistance to electrodeposited steel sheets, and also has excellent performance even after being immersed in water. It was also found that the storage stability was excellent without causing any deterioration in performance. Therefore, the protective vinyl chloride plastisol composition of the present invention can greatly contribute to improving the durability of automobiles.

Claims (1)

[Claims] 1. In a vinyl chloride plastisol composition for protecting automobiles, which contains a vinyl chloride resin, a liquid plasticizer, a filler, an adhesion agent and, if necessary, a coloring agent and an organic solvent, the adhesion agent (A) blocked isocyanate and (B) polyamide (A):(B)=1:5~
A vinyl chloride plastisol composition for protecting automobiles, which is a mixture of 1:10 (equivalent ratio) and contains 1 to 30 parts by weight of the mixture per 100 parts by weight of vinyl chloride resin.