JPS6362546B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a weld double hot melt rust preventive composition, and more particularly to a composition used for the rust prevention of spot welded overlapping surfaces. It is an object of the present invention to provide a weldable hot melt rust preventive composition that has good film adhesion, physical strength, water resistance, and moisture resistance. Conventionally, spot welding has been widely used in most metal processing industries because it is a very simple and efficient method of joining metal plates. For the most part, this is done untreated and naked. As a result, spot welding overlapping surfaces are prone to rust, and since it is impossible to completely prevent rust after welding, we have created a rust preventive for spot welding overlapping surfaces with excellent rust prevention power and weldability. The development of drugs has been a major challenge for many years. Currently, zinc-rich paint is used in some parts of the industry to prevent rust on spot welded overlapping surfaces, but since it is a solvent-based paint, there is a risk of fire due to organic solvents and hygienic problems for the human body. However, it has not yet become widely popular. In addition, the two-coat zinc chrome metal formulation is made by baking an epoxy resin zinc-rich paint onto a steel plate coated with a chemical solution containing chromic acid and zinc powder, etc., and has excellent rust prevention properties and good spot weldability. Therefore, it is used as a rust prevention treatment that can be spot welded, but the painting process is two steps and the baking temperature is very high, resulting in poor workability. others,
Due to the toxicity of chromic acid, it is rarely used as a rust preventive agent for spot welded mating surfaces. The present inventor focused on the above-mentioned drawbacks of conventional products, and found that they do not have the drawbacks due to the use of organic solvents, have good workability (can be done in one step instead of two steps), and meet the requirements for a weldable rust preventive agent. For example, as a result of continuing research to develop a rust preventive agent and a rust preventive agent that has good weldability and excellent paint film adhesion, water resistance, and moisture resistance, the present invention has been completed. The invention comprises (a) 20 to 80 parts by weight of at least one of petrolatum oxide, wax oxide, metal salts or esters thereof, metal salts of lanolin, and metal salts of petroleum sulfonic acids or synthetic sulfonic acids; petrolatum;
At least one of lanolin and wax, 20~
mixture consisting of 80 parts by weight, 10 to 90 parts by weight, (b) polyethylene, polypropylene, ethylene.
10 to 90 parts by weight of at least one of acrylic acid copolymer, ethylene/ethyl acrylate copolymer, and ethylene/vinyl acetate copolymer, and (a)
For 100 parts by weight of (b), (c) conductive filler with a volume resistance of 30Ω・cm or less, 10~
This relates to a weldable hot melt rust preventive composition characterized in that it contains 300 parts by weight. Petrolatum oxide, oxidized wax, metal salts or esters thereof, lanolin metal salts, metal salts of petroleum sulfonic acid or synthetic sulfonic acid, petrolatum, lanolin, and wax used in the present invention include general wax-based preventive agents. What has traditionally been used as rust paint can be used in a wide range of applications.
Among them, those having a softening point of about 40 to 180°C can be preferably used. Furthermore, the metal of each metal salt in each of the above components is not particularly limited, and many metals can be used, such as alkali metals such as sodium, potassium, and lithium, alkaline earths such as calcium, barium, and strontium. Examples include similar metals, molybdenum, zinc, and the like. Among these, alkali metals and alkaline earth metals are preferred from the viewpoint of antirust effect. Of course, these metal salts may contain one kind of metal or two or more kinds of metals. As the polyethylene component (b), high-density polyethylene and low-density polyethylene can be used. As the polypropylene, in addition to isotactic polypropylene, amorphous atactic polypropylene as a by-product can also be used. Ethylene-acrylic acid copolymer (hereinafter referred to as EAA) is produced by high-pressure polymerization reaction of ethylene and acrylic acid, and the content of acrylic acid is 1 to 1.
20% by weight is preferred. Ethylene/ethyl acrylate copolymer (hereinafter referred to as EEA) has an ethyl acrylate content of approximately 5 to 25% by weight, and ethylene/vinyl acetate copolymer (hereinafter referred to as EVA)
) preferably has a vinyl acetate content of 5 to 30%. The melt index of each of these resins is preferably about 5 to 500. The conductive filler (c) has a volume resistivity of 30
Any material with a resistance of Ω・cm or less can be used.
Examples of conductive fillers with a volume resistivity of 30Ω・cm or less include carbon black, graphite powder, silver powder, copper powder, nickel powder, aluminum powder, zinc powder, stainless steel powder, iron phosphide powder, copper-silver composite powder, and nickel. -Silver composite powder, aluminum flakes, stainless steel flakes, nickel flakes, zinc flakes, flaky graphite, carbon fibers, aluminum fibers, stainless fibers, brass fibers, carbon spheres, silver coated glass beads, silver coated glass fibers, etc. Yes, any of these can be used. However, due to the price, marketability, and welding strength of these materials, carbon black, carbon fiber, graphite powder, flaky graphite,
iron phosphide, stainless steel powder, stainless steel flakes,
Zinc dust and flaky zinc dust are preferred. As the carbon black, either acetylene black or furnace black can be used, but from the viewpoint of electrical conductivity, acetylene black is preferable because it can easily form a chain structure, which is a higher-order structure. There are two types of carbon fibers, PAN type and Pitch type, both of which are made from polyacrylonitrile, and both can be used in the present invention. The carbon fiber preferably has a fiber diameter of 10 to 30 μm and a fiber length of 0.05 to 1 mm. For other various fibers, the fiber diameter is 10~
A fiber having a fiber length of about 30 μm and a fiber length of about 0.05 to 1 mm is preferably used. In addition, the sizes of the various powders mentioned above are approximately 0.02 to 500 μm in diameter, and the sizes of flakes and scale-like conductive powders are 0.1 to 50 μm in thickness and particle diameters of 2 to 500 μm.
A thickness of about 1000 μm is preferable. Among the above-mentioned components, the component listed in (a) is a component for imparting excellent rust-preventive power to the composition, and includes petrolatum oxide, wax oxide, metal salts or esters thereof, lanolin metal salts, and petroleum oxide. At least one metal salt of sulfonic acid or synthetic sulfonic acid
seeds, 20-80 parts, preferably 30-70 parts, at least one of petrolatum, lanolin and wax, 20
10 of a mixture consisting of ~80 parts, preferably 30-70 parts
~90 parts are used, preferably 20-70 parts. If the ratio of the former to the latter is less than 20:80, the adhesion and rust prevention will be poor, and if it exceeds 80:20, the paint film will remain sticky and the polarity will become strong, resulting in poor water resistance. This is not preferable because the properties and moisture resistance deteriorate. The synthetic resin component described in (b) is a component for imparting physical strength and flexibility to the composition,
Polyethylene, polypropylene, EAA, EEA,
10 to 90 parts of at least one type of EVA, preferably
Use 30-80 copies. The mixing ratio of component (a) and component (b) is
If the ratio is less than 10:90, the desired rust prevention ability of the present invention will not be obtained, and if it exceeds 90:10, the bending resistance of the coating film will be affected.
It is not preferred because it has poor physical strength such as tensile strength. Component (c) is a component that lowers the volume resistance of the coating film and gives it excellent spot welding properties, and it has a conductivity with a volume resistance of 30Ω・cm or less per 100 parts of the sum of (a) and (b). filling material
10 to 300 parts are used, preferably 30 to 250 parts. If the amount of the conductive filler is less than 10 parts, the spot weldability will be poor, and if it is more than 300 parts, the coating film will become brittle and the melt viscosity will become high, resulting in poor painting workability, which is not preferable. In the composition of the present invention, in addition to the above-mentioned components, various components commonly used in this type of composition can be used as appropriate.
Such components include, for example, petroleum resins, cyclized rubber, coumaron indene resins, polybutene resins, and other synthetic resins that are compatible with each of the above components, tin oxide,
Examples include metal oxides such as zinc oxide, color pigments such as titanium dioxide and red iron oxide, extender pigments such as talc, calcium carbonate, and kaolin clay, antifoaming agents, and dispersants. The composition of the present invention is prepared by mixing components (a) and (b) under heating and melting, then adding component (c) thereto, and dispersing the mixture using, for example, a dissolver, a heated roll mill, etc.
Produced by mixing. The thus obtained weldable hotmelt rust preventive composition of the present invention can be applied to spot welded overlapping surfaces using a general hotmelt applicator, or it can be applied to spot welded overlapping surfaces by pre-forming a film or sheet of a certain size and spot welding overlapping. It can be used by spot welding by sandwiching it between mating surfaces and then heating and melting it to a constant temperature. The well double hot melt rust preventive agent of the present invention is
It has excellent rust prevention and spot welding properties, as well as good paint film adhesion, physical strength, water resistance and moisture resistance, and there is no risk of fire or hygienic problems to the human body during use, making it easy to work with. Because the properties are good,
It can be used in most metal processing industries such as vehicles, electrical equipment, various machines, office equipment, steel furniture, building materials, etc., and has excellent rust prevention effects on spot welded overlapping surfaces. When performing spot welding using the composition of the present invention, the means for spot welding is not particularly limited, but
Spot welding is preferably performed with the composition of the present invention interposed between the overlapping surfaces. More specifically, a method of placing the composition of the present invention on a spot-welded overlapping surface, performing spot welding, and then heating and melting the composition; A method in which the composition is applied in the form of a sheet or film in advance, this sheet or film is interposed between the spot welding overlapping surfaces, and spot welding is performed; a method in which the composition is in the form of a powder; Examples include a method of intervening spot welds on overlapping surfaces. Examples will be shown below, but the present invention is not limited to the following examples. Note that in the examples, parts indicate parts by weight, and percentages indicate weight %. Examples 1 to 38 The components (a) and (b) in the proportions shown in (Part 1) to (Part 2) of Table 1 below were stirred and mixed with a dissolver while heating at 200°C. Component (c) shown in Table (Part 3) was added and further stirred and mixed using a dissolver to obtain a weldable hot melt rust preventive composition of the present invention.

【table】

【table】

【table】

【table】

【table】

[Table] Comparative Examples 1 to 11 Comparative weld double hot melt rust preventive compositions were obtained in the same manner as Examples 1 to 36, except that the rust preventive composition was changed to that shown in Table 2.

【table】

[Table] The properties of each well double hot melt rust preventive agent obtained in Examples and Comparative Examples were tested and evaluated by the method described below. (1) The test piece is a 200 μm thick film of a sample heated and melted at 200℃ on one side of a steel plate (70 x 1.50 x 2 mm).
It was coated with a spatula (one coat) and allowed to cool to room temperature (20°C) to prepare a test piece. The spot weldability test pieces were made of two steel plates (70×150×
0.8mm) parallel to the long side, 25mm from the edge.
A sample heated and melted at 200℃ is applied to the width of
After coating with a spatula to a thickness of 200 μm, another steel plate was immediately placed on top of it with the same width and adhered to form a test piece. (2) As a test for rust prevention ability, a salt spray test and a salt water resistance test were conducted. The salt spray test was conducted for 1000 hours according to the salt spray test method of JIS Z 2371, and the degree of rust on the test piece was observed. Salt water resistance test specimens at 20℃
After being immersed in a 3% sodium chloride aqueous solution for 3 months, the condition of the coating film was observed. The results were divided into three grades: no abnormality (○), somewhat rust-proof (△), and considerably rust-proof (x). (3) Adhesion was tested according to JIS A 6909 (Synthetic resin emulsion sand wall spray material) - 5.5 Adhesion strength test method, and the adhesion strength was measured in kg/cm ²
The evaluation was divided into 7 or more (○), 4 or more and less than 7 (△), and less than 4 (x). (4) Adhesiveness was evaluated by touching the coated surface with the tip of a finger and dividing it into three grades: no tackiness (〇), slightly tackiness (△), and slightly tackiness (×). (5) Water resistance: After immersing the test piece in tap water at 20°C for one month, the state of the coating film was observed. No abnormality (〇);
Slight softening and swelling (△), considerable softening and swelling (×) 3
The evaluation was divided into stages. (6) Moisture resistance is determined by placing the test piece in a humidity tester at 50℃ and 98%RH, and observing the condition of the coating after testing for one month.No abnormality (〇), slight softening and swelling (△)
The evaluation was divided into three stages: considerable softening and swelling (×). (7) A tensile test and a bending resistance test were conducted to test the physical strength of the coating film. The tensile test was conducted in accordance with JIS K 6301-3 (vulcanized rubber physical test method, tensile test).
The results are expressed in Kg/ ^cm2 , with 10 or more (○), 5 or more and less than 10 (△), and less than 5 (×).
The bending resistance was determined by bending a test piece along a metal rod with a diameter of 20 mm and observing the state of the coating film. The results were divided into three grades: no abnormality (○), slight cracking (△), and considerable cracking (x). (9) For spot weldability, if spot welding is possible under condition a (○), if it is not possible under condition a but possible under condition b (△), if it is not possible even under condition b (×)
The evaluation was divided into three stages.

【table】 The results of these tests are shown in Table 4 below.

【table】

[Table] As is clear from the test results listed in Table 4,
The weldable hotmelt rust preventive compositions of the present invention obtained in Examples 1 to 36 showed good results in all test items, including excellent rust prevention ability, spot weldability,
It was demonstrated that it has excellent adhesion, physical strength, water resistance, and moisture resistance. On the other hand, petrolatum oxide in component (a),
The mixing ratio of at least one of oxidized wax, metal salt or ester thereof, lanolin metal salt, and metal salt of petroleum sulfonic acid or synthetic sulfonic acid and at least one of petrolatum, lanolin, and wax exceeds 80:20. The composition of Comparative Example 1, which had a ratio of less than 20:8, had poor anti-corrosion ability and adhesion. a) do not use ingredients or
Comparative Examples 3 and 4, in which the ratio of component (a) to component (b) is less than 10:90, have poor rust prevention ability. Comparative Examples 5 and 6 where the ratio exceeds 90:10 have poor physical strength such as bending resistance and tensile strength, and either component (c) is not used or the sum of (a) and (b)
Comparative Examples 7 to 9 in which the amount of component (c) added was less than 10 parts per 100 parts had poor spot welding properties, and Comparative Example 10 in which the amount of component (c) added exceeded 300 parts. It is also clear from Table 4 that the compositions of Nos. 1 and 11 have poor bending resistance of the coating film.

Claims (1)

[Scope of Claims] 1 (a) At least one of petrolatum oxide, wax oxide, metal salts or esters thereof, metal salts of lanolin, and metal salts of petroleum sulfonic acids or synthetic sulfonic acids, 20 to 80 parts by weight, petrolatum , at least one of lanolin and wax;
mixture consisting of 20 to 80 parts by weight, 10 to 90 parts by weight, (b) polyethylene, polypropylene, ethylene.
10 to 90 parts by weight of at least one of acrylic acid copolymer, ethylene/ethyl acrylate copolymer, and ethylene/vinyl acetate copolymer, and (a)
For 100 parts by weight of (b), (c) conductive filler with a volume resistance of 30Ω・cm or less, 10~
300 parts by weight of a well double hot melt rust preventive composition. 2. The weldable hot melt rust preventive composition according to claim 1, wherein the metal salt of the metal is an alkali metal or/and an alkaline earth metal. 3. A patent in which the conductive filler is at least one of carbon black, carbon fiber, graphite powder, scaly graphite, iron phosphide powder, stainless steel powder, stainless steel flakes, zinc powder, and scaly zinc powder. Claim 1 or 2
The well double hot melt rust preventive composition described in Section 1.