JPS6097072A - Pitching resistant coating method of car body - Google Patents

Abstract

PURPOSE:To obtain a pitching resistant paint film, by spraying a rubber-asphalt emulsion composition and a coagulant composition of an ionic compound from separate sprayers. CONSTITUTION:A rubber-asphalt emulsion composition containing 10-60wt% of a rubber component and a coagulant composition containing 5-15wt% of an ionic compound containing Ca, Mg or the like and an NH4-ion are respectively sprayed from separate sprayers to be mixed and contacted to each other in air and applied to the desired region of a car body to form a film. Film thus obtained is excellent in properties such as impact resistance, anti-wear property or the like.

Description

Detailed Description of the Invention: A chipping-resistant paint composed of a composition containing a rubber-asphalt emulsion and a coagulant composition composed of an aqueous solution of an ionic compound is applied to the underside of the floor of an automobile body. Regarding the painting method to be applied.

Recently, in the automobile industry, IE and VA techniques have been used to meet the diversification of needs, taking into consideration durability, resource conservation, rationalization of manufacturing and assembly, and reduction of production costs. In particular, while a car is running, pebbles and dirt are thrown up, and these are thrown up on the underside of the car body floor, wheel house, etc.
It collides with parts such as the inner surface of the door, and this impact partially damages the bituminous material of the conventional anti-chip and anti-corrosion coating from the surface, and ultimately reaches the base steel plate, causing the coating to peel off. There were problems such as rust and corrosion on the steel plates. In addition, the bituminous material is dissolved in an organic solvent and applied to the airless type (gray coating and heat drying), so the use of organic solvents causes health and safety issues during work, and air pollution. However, although bituminous materials are cheap, used in large quantities, and have a proven track record, their physical properties include flexibility at low temperatures and resistance to flying stones. Currently, there are problems with abrasion and performance is not fully satisfied.

Especially in areas near the coast that are exposed to sea breeze. In the cold regions where cars are exposed to freezing temperatures, the durability of automobiles has become a serious social problem. On the other hand, as an alternative to such bituminous materials, synthetic 'fd fat emulsions, vinyl chloride resin plastisols, epoxy resins, and urethane have been developed. Synthetic resins such as resin are mainly used in specific areas such as the underside of doors.

However, although these materials have excellent chipping resistance, they have problems such as the inability to apply thick coatings, the high material cost and the need for one piece, and the need for special bake-hardening equipment. .

Therefore, the inventors of the present invention solved the above-mentioned problems with bituminous materials, and in response to the request for the development of materials that are inexpensive and suitable for painting work conditions, the present inventors conducted intensive research. The chipping-resistant paint composed of an asphalt emulsion composition and a coagulant composition containing an ionic compound forms an excellent chipping- and rust-proofing coating on the underside of the car body floor, etc. [7] The present invention has been completed.

That is, in the present invention, 10 to 60% (multiple installation).

A rubber-asphalt emulsion composition containing a rubber component of ca, Mg, A, 1,
A coagulant consisting of an aqueous solution containing Zn and NT (5 to 15 ionic compounds containing ions selected from 4 ions)
This invention relates to a method for coating car bodies with anti-tinobisig, which is characterized by spraying 1HM products from separate spray holes and mixing and contacting them in the air, while painting desired parts of the car body to form a coating film. - The chipping-resistant paint film as used in the present invention is a paint film that has the function of protecting the underside of a car body from impact caused by a 1-J collision with a flying stone or the like from the road surface. , impact resistance, abrasion resistance, low-temperature flexibility, rust prevention of the underlying steel plate, adhesion, and oil resistance.

The rubber-asphalt emulsion composition used in the present invention is composed of an emulsion containing a rubber component and an asphalt component as essential components, and the ratio of rubber in the emulsion composition is 10 to 60, preferably 20 to 55.
% range. 1/4 rubber component
If it is less than 0%, the flexibility at low temperatures will be poor, and if the coating film is bent, it will easily crack or crack, and if it exceeds 60%, the flexibility at low temperatures will be good, but This is not desirable because the rust prevention properties of the steel plate are poor due to the lack of asphalt components.

Typical rubber components include natural rubber, styrene-butadiene copolymer rubber, butyl rubber, polybutadiene copolymer, polyisobrene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, acrylic ester copolymer rubber, etc. One type or a mixture of two or more of these can be used. Particularly preferred is a copolymer rubber based on the properties and storage stability. Such styrene-butadiene copolymer rubbers include, for example, styrene and butadiene random or block copolymer rubbers and carboxyl group-modified styrene and butadiene copolymer rubbers, preferably with a styrene copolymerization ratio of 20 to 20. 70% of them are unused. In addition, rubbers in which acrylic esters, methacrylic esters (methyl methacrylate, butyl methacrylate, etc.), acrylonitrile, etc. are copolymerized as one component of the above-mentioned rubber can also be used.

These rubber components are usually used in the form of an emulsion (latex) with a solid content of 50% or more obtained by emulsion polymerization of the monomer in the presence of an anionic surfactant according to a conventional method.

On the other hand, as the asphalt component, for example, natural asphalt, straight asphalt, blown asphalt, etc. are used.

VrCid to obtain a rubber asphalt emulsion by blending one part of such asphalt component with the above rubber component, for example, a method of directly adding hot-molten asphalt to the rubber component while stirring, hot-melting emulsification, or a pre-heated interface. A method may be adopted in which hot molten asphalt is added dropwise (emulsified) to an aqueous activator solution under stirring to obtain an asphalt emulsion, and this is mixed with one part of the rubber component.

For this rubber-asphalt emulsion, a rubber-asphalt emulsion composition is prepared by adding and mixing all conventional preservatives, fillers, rust preventives, antifreeze agents, thickeners, etc. In particular, high concentration (e.g. 75% solids or more) is required in order to reduce the volume shrinkage due to drying due to the large coating thickness.
It is desirable to set it to . In addition, it is important to adjust the viscosity and viscosity in order to prevent flow and dripping on the coating surface, and to improve coating workability and film formation properties during coating. Ding? It is recommended that the viscosity range is 10,000 to 30,000 cps/20° C1 viscosity coefficient (the value divided by the viscosity at a shear rate of 2 RPM in a B-type viscometer and the viscosity at 92QRPM) is in the range of 30 to 55. Preferably 7.

The coagulant composition used in the present invention is composed of an aqueous solution containing 5 to 15 ionic compounds.

In the above ionic compounds, metal ions of divalent or higher valence (e.g. Ca, Mg, Zn, Al ions) and N
Refers to ionically bonded inorganic and organic compounds containing ions selected from U4 ions, specifically CaC
l2, ca (OT(> 2, Carol, (
CH CX Magnesium, zinc acetate, alum, aluminum chloride, aluminum sulfate, ammonium sulfate, ammonium nitrate, ammonium chloride, amino acid zinc salt, amino acid magnesium salt, etc. are mentioned, and one or more of these can be used in combination to add 0.5% to water. A coagulant aqueous solution is prepared by dissolving the coagulant in a range of ~15%. Such ionic compounds have the property of neutralizing the surface potential of emulsion particles and coagulating them, so they destroy the emulsion particles almost instantly when the ionic compound and the emulsion particles come into contact, causing the particles to fuse. The emulsion particles form a film continuously and expel water as a medium to form a coating film. Therefore, fusing emulsion particles and forming a film by such a method is useful for later drying of water and its promotion, and the less drying energy is required, the more effective it is.

The chipping-resistant painting method for car bodies according to the present invention involves simultaneously applying the above-mentioned rubber-asphalt emulsion composition (hereinafter referred to as rubber-asphalt composition) and coagulant composition to the surface to be painted. , and then drying to form a rubber asphalt coating (!).Specifically, both compositions are mixed and contacted in the air while being sprayed by an airless spray device through separate nozzle holes. As a result, some of the emulsion particles are fused before being applied to the object to be coated, so it is possible to apply a thick coating, and there is no flow deformation or toughness after coating, and it is possible to achieve the desired thickness. A coating film can be obtained.In particular, the solid content ratio of the rubber asphalt composition and coagulant composition is
It may be set in the range of 100105 to 15 (weight ratio) from the relationship between the aggregation/fusion rate of the emulsion and the adhesion to the object to be coated.

For this purpose, two or more spray guns whose spray areas are adjusted to overlap may be used, or a two-headed spray gun (for example, 6g GMPLU manufactured by Pincus Manufacturing Company, USA) may be used.
RAL COMPONENT 5PRA, Y GUNJ
) can be used. Also, as the spraying method, it is preferable to use an airless spray gun, which causes less scattering of the spray mist.

The chipping-resistant paint made of the above-mentioned rubber asphalt composition and coagulant A11lt is applied to the lower surface of the car body, such as the lower surface of the floor, the lower surface of the wheels, and the lower surface of the door, which are likely to be hit by flying stones. In this process, the press-molded car body is degreased, washed, and surface treated (((chip-resistant paint is applied to a thickness of 0.5 to 5.0 mm and dried at room temperature or under heat. This can also be carried out in a drying oven after applying the paint in the next step.

Next, the present invention will be explained in more detail with reference to Examples. Note that "1 part" means "part by weight."

Example 1 Rubber asphalt group In Rubber asphalt emulsion 100 parts Calcium carbonate 80 parts Ethylene glycol 3 parts Carbon black 2 parts Thickener (cellulose type) 5 parts Water 10 parts Viscosity 18000 cps, solid content 82 Coagulant composition alum Dissolve in water to prepare a 20% aqueous solution.

Example 2 Rubber asphalt composition Rubber asphalt emulsion 100 parts Calcium carbonate 90 parts Ethylene glycol: (1 part antifoaming agent 1 part thickener (cellulose) 3 parts water 3 parts Viscosity 21000 cps, solid content 83% Coagulant set 1 part Water 80 parts Calcium chloride 5 parts Zinc acetate 15 parts Rubber asphalt composition and coagulant composition, respectively, using airless pumps (pressure ratio 35:1., 25:1)
The solid content weight ratio of the rubber asphalt composition and coagulant composition was 100/10, and the discharge amount was 5, Q.
A steel plate (30X) adjusted to 7 kg and pre-electrodeposited
30m) K3. Spray coat at almost the same time at Qkg/mr. As a result, the painted surface of the chipping-resistant paint obtained was in a semi-gel state and had shape retention properties. Regarding the surface finish, the water separated and the coating had a peel-like appearance, but the coating thickness was uniform, and the coating after drying was non-tacky and no defects such as pinholes were observed. A test piece made from the obtained painted board was subjected to a chipping resistance test. That is, 2.5 kII No. 106 crushed stone was placed on the test piece at 7-pressure 41c9/
A flying stone was thrown under cr/l conditions, and it was placed in a salt spray test machine for 2 hours.
After exposing for 00 hours, the rusting property is evaluated by counting the number of rusted pieces and displaying a score. Table 1 shows the evaluation results of rust resistance, low-temperature flexibility, and adhesion.

Comparative Example 1 100 parts of styrene sea-butadiene copolymer latex (trade name "J 8 RO561J" manufactured by Japan Synthetic Rubber Co., Ltd.)
A chipping-resistant paint is prepared by adding and mixing 80 parts of calcium carbonate, 3 parts of ethylene glycol, 2 parts of carbon black, 5 parts of a thickener, and 10 parts of water. Viscosity 23000
cps, 81% solids.

Such comparative paints were spray applied, but only 1 to 8 coats at a time.
It was possible to apply only up to a coating amount of kg 7 m'.

When the pressure exceeded 2.0 kg/mF, the undried coating film slipped off when held vertically, causing sagging. 1.8 kg
After drying, the coating film coated with a thickness of 7 m" was strained in the same manner as in Example 1 to evaluate chipping resistance (rusting resistance). The results are shown in Table 1, together with low oil bending property and adhesion.

Table 1 Note ■) Low-temperature flexibility: After leaving the test piece at -20'O for 2 hours or more, it was bent through a 25 mmφ mandrel in that atmosphere. A coating with no cracks or peeling is rated O.

■) Adhesiveness: Cut the adhesive interface of the paint on the wipe test piece with a knife, and evaluate the adhesiveness by hand-cutting while pulling one end. Mark as ○ what is destroyed from the paint.

As is clear from the results in Table 1, the method of the present invention allows for thick coating at one time, and forms a coating film with excellent chipping resistance (rusting resistance after chipping). .

Patent applicant Sunstar Giken Co., Ltd. Agent: Patent attorney: 1 other person, including Aoshi and Shiro

Claims (1)

[Scope of Claims] A rubber-asphalt emulsion composition containing a rubber component of 110 to 60% by weight, Ca, Mg, and Al. A coagulant composition consisting of an aqueous solution containing 5 to 15% by weight of an ionic compound containing ions selected from Zn and NI (4 ions) is sprayed from separate spray holes and brought into contact with each other in the air to form the desired shape of the car body. A chipping-resistant coating method for a car body, which is characterized by applying the coating to the parts and shaping the coating film. 2. A patent in which the rubber component is styrene-butadiene copolymer rubber or acrylic ester copolymer rubber. The method according to claim 1. 3. The method according to claim 1, wherein the solid content ratio of the rubber-asphalt emulsion composition and coagulant composition is in the range of 10070.5 to 15. 4. The method according to claim 1, wherein the desired part of the vehicle body is the lower surface of the floor, the wheel house and/or the lower surface of the door. 5.- The coating thickness of the coating film is 05 to 5.Q'; nm.
The method according to claim 1.