JPH03143972A - Underfloor member of automobile - Google Patents

Abstract

PURPOSE:To obtain an automotive underfloor member with excellent wear resistance and chem. resistance and without toxicity or flammability by coating an automotive underfloor member with a water-based compsn. consisting of a specified water-based emulsion polymer and a fibrous or acicular filler. CONSTITUTION:An automotive underfloor member coated with a water-based coating compsn. contg. a water-based emulsion polymer consisting of a polymer of one or more monoethylenically unsatd. monomers with a vinyl or vinylidene group and one or more org. or inorg. fibrous or acicular fillers with a diameter of 0.2-100mum as ingredients. The underfloor member are a fuel pipe, a fuel tank, a side sill, etc., positioned under the floor of an automobile. The fuel pipe and the side sill are usually made of iron and the fuel tank is usually made of a terned sheet (an iron sheet coated with a lead-tin alloy).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a member disposed under the floor of an automobile.

[Conventional technology]

For example, parts such as fuel pipes, fuel tanks, and side sills placed under the floor of a car may be damaged by stones, sand, etc. thrown up while the car is running (referred to as chipping), and may be damaged by rainwater or sprinkled on roads to prevent freezing. Tar paint, tar-urethane paint, polyvinyl chloride sol, etc. are applied to prevent corrosion caused by contact with inorganic salts.

The above paint forms a thick film of approximately 500 to 100 microns on the surface of the member, and its viscoelasticity buffers flying pebbles and the like to prevent scratches on the surface.
Prevent direct contact with inorganic salts, etc.

[Problem to be solved by the invention]

However, the above-mentioned conventional paints lack durability, and as mentioned above, it was only possible to satisfactorily protect the surfaces of the above-mentioned members with a thick coating film of about 500-1000 microns.

Furthermore, the above-mentioned conventional paints contain organic solvents and organic plasticizers, are toxic and flammable, and are difficult to handle.

[Means to solve the problem]

The present invention, as a means for solving the above-mentioned conventional problems,
An aqueous emulsion polymer (A) consisting of one or more polymers of mono-ethylenically unsaturated monomers having one vinyl group or vinylidene group and a diameter of 0.3 to 10
Provided is an automobile underfloor member, the surface of which is coated with an aqueous coating composition containing one or more organic or inorganic fibrous or acicular fillers (B) having a size of 0 microns as an essential component. It is something to do.

[Aqueous emulsion polymer (A)]

The aqueous emulsion polymer (A) used in the present invention is an aqueous emulsion polymer (A) consisting of one or more polymers of mono-ethylenically unsaturated monomers having one vinyl group or vinylidene group. It is.

Mono-containing the above one vinyl group or vinylidene group
Ethylenically unsaturated monomers (hereinafter simply referred to as monomers) include methyl acrylate, ethyl acrylate, n-
Butyl acrylate, 1so-butyl nacrylate, 2
-Ethylhexyl acrylate, cyclohexyl acrylate, tetrahydrofuryl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate.

Alkyl acrylates and alkyl methacrylates such as 1so-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, stearyl methacrylate, lauryl methacrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, 1so-butyl vinyl ether , vinyl ethers such as n-butyl vinyl ether, styrenes such as styrene and α-methylstyrene, nitrile monomers such as acrylonitrile and methacrylate, vinyl fatty acids such as vinyl acetate and vinyl propionate, vinyl chloride, vinylidene chloride, fluoride, etc. Halogen-containing QLM bodies such as vinyl chloride and vinylidene fluoride, olefins such as ethylene and propylene,
Dienes such as isoprene, chloroprene, butadiene,
Acrylic acid, methacrylic acid, itaconic acid, maleic acid,
α-β unsaturated carboxylic acids such as atorbic acid, citraconic acid, crotonic acid, β-hydroxyethyl acrylate, β
- Hydroxyl group-containing monomers such as hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, allyl alcohol, amides such as acrylamide, methacrylamide, diacetone acrylamide, and other vinylpyrrolidone, vinylpyridine, vinyl Examples include water-soluble monomers such as carbazole, and epoxy monomers such as glycidyl acrylate, glycidyl methacrylate, and glycidyl allyl ether.

The above monomers are emulsified in water using a surfactant and emulsion polymerized using a polymerization initiator, ultraviolet rays, radiation, etc. Examples of the surfactant used in the emulsion polymerization include anionic surfactants such as higher alcohol sulfate (Na salt or amine salt), alkylaryl sulfonate (Na salt), alkylnaphthalene sulfonate, and alkyl phosphate. , dialkyl sulfosuccinate, rosin soap, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, sorbitan alkyl ester , polyoxyethylene sorbitan alkyl ester, and examples of cationic surfactants include trimethylaminoethyl alkylamide halogenide, alkylpyridinium sulfate, and alkyltrimethylammonium halide. The above examples are not intended to limit the invention.

Polymerization initiators used in the above emulsion polymerization include lylium persulfate and sodium persulfate.

Commonly used polymerization initiators such as ammonium persulfate, potassium perborate, sodium perborate, hydrogen peroxide, and water-soluble azo compounds are used, and sodium sulfite and hyposulfite are used as decomposition accelerators for the polymerization initiators. -Reducing agents such as lithium, ascorbic acid, copper sulfate, etc. may also be used.

In the production of the aqueous emulsion polymer (A) of the present invention, the above monomer is usually in the range of about 30 to 65% by weight, the above surfactant is usually in the range of 1 to 10% by weight, and the above-mentioned The amount of the polymerization initiator is usually about 0.01 to 5% by weight.

Further, in the present invention, the aqueous emulsion polymer (A) is polyvinyl alcohol, polyacrylates, carboxymethyl cellulose, methoxy cellulose, ethoxy cellulose, starch, or modified starch.

Thickeners or protective colloids such as gelatin and casein,
Wetting agents or viscosity modifiers such as ethylene glycol, propylene glycol, and glycerin.

It may contain ultraviolet absorbers, anti-aging agents, etc.

It is desirable that vinylidene chloride and/or vinyl chloride be copolymerized into the polymer of the aqueous emulsion polymer (A) of the present invention. The vinylidene chloride and/or vinyl chloride is usually present in the polymer in an amount of 5 to 90% by weight. Furthermore, both vinylidene chloride and vinyl chloride are copolymerized in the above polymer, and vinylidene chloride and/or vinyl chloride are copolymerized.
Alternatively, the total amount of vinyl chloride is 5 to 90% by weight, and the proportion of vinylidene chloride is preferably 5 to 80 parts by weight per 100 parts by weight of the total of vinylidene chloride and vinyl chloride.

Furthermore, the above vinylidene chloride (a) and vinyl chloride (b)
is preferably copolymerized with one or more alkyl acrylates and/or alkyl methacrylates (c) containing 1 to 12 carbon atoms in the alkyl group. In the above polymer, vinylidene chloride (a) is usually used.
and vinyl chloride (b) is in the range of 20:80 to 95=5, vinylidene chloride (a) is contained in the polymer in an amount of 75% by weight or less, and the alkyl acrylate and/or alkyl methacrylate (c) is the sum of vinylidene chloride (a) and vinyl chloride (b) of 10
When it is set as 0 parts by weight, it is contained in 2 to 45 parts by weight.

Further, the copolymer of vinylidene chloride (a), vinyl chloride (b), alkyl acrylate and/or alkyl methacrylate (c), which is the polymer of the aqueous emulsion polymer (A) of the present invention, contains α-β unsaturated carbon. It is desirable that one or more acids (d) are included. In this case, α-β unsaturated carboxylic acid (d) is present in the copolymer with 3
It is contained in a proportion of 0% by weight or less.

[Filler (B)]

The filler (B) used in the present invention has a diameter of 0.3 to 10
It is an organic or inorganic fibrous or acicular filler with a size of 0 micron and a length of 50 to 2000 microns, and an aspect ratio (length/diameter) of 3 to 2000 microns.
5000 is desirable. Examples of such fillers include rock wool, metal fibers, carbon fibers, short potassium titanate fibers, sepiolite, glass fibers, wollastonite, inorganic fillers such as fibrous basic magnesium sulfate, polyester fibers, and acrylic fibers. , organic fillers such as polyamide fibers, acetate fibers, urethane fibers, etc. The above filler (B) is usually added in an amount of 0.5 to 40% by weight in the aqueous coating composition of the present invention.

[Third component]

In addition to the aqueous emulsion polymer (A) and the filler (B), the aqueous coating composition of the present invention may further contain pigments such as calcium carbonate, titanium white, chrome yellow, carbon black, rust preventives, etc. Particularly desirable is the addition of anticorrosive pigments. Examples of the above rust-preventive pigments include potassium, sodium, calcium, magnesium, barium, strontium, zinc, lead, manganese, iron, and chromium in oxyacids such as glycolic acid, lactic acid, β-oxybutyric acid, malic acid, tartaric acid, and citric acid. , salts with metals such as molybdenum and tungsten, calcium silica, barium metaborate, and zinc phosphate. Two or more of these may be used in combination.

[Preparation]

The aqueous coating composition of the present invention is prepared by kneading the above composition using a conventional kneading machine such as a three-roll mill, a ball mill, or an atomizer-1 mill.

[Automotive underfloor components]

The underfloor components of automobiles that are the object of the present invention are fuel pipes, fuel tanks, side sills, etc. arranged under the floor of automobiles.The fuel pipes and side sills are usually made of iron, and the fuel tank is usually made of tan sheet (lead-tin alloy). is the material. The surface of the member may be subjected to galvanizing, chrome plating, zinc-chromate treatment, etc. prior to coating with the aqueous coating composition of the present invention, or may be precoated with a black paint.

〔Painting〕

The aqueous coating composition of the present invention is usually applied to the surface of the above-mentioned underfloor member by a general coating method such as dipping, spray coating, or brush coating. A thickness of about 250 to 500 microns is usually sufficient for the coating film.

The coating is applied to all or part of the surface (for example, only the lower surface) of the underfloor member.

[Effect]

When the aqueous coating composition of the present invention is applied to the surface of an object to be coated to form a coating film, the surface to be coated is covered with the filler (B) in the form of fibers or needles filled in the coating film. In this protected state, the filler (B) protects the surface of the underfloor member from pebbles, sand, etc. blown away during driving, and protects the coated surface from scratches. However, if the filler (B) has a diameter of 0.3 microns or less, the mechanical strength of the filler (B) is weak, and there is a risk that the filler (B) will be damaged by collisions with pebbles, sand, etc., resulting in a decrease in coverage. If the diameter is 100 microns or more, the filler (B) filled in the formed coating film will not be dense, and gaps will be created between the fillers (8), resulting in poor coverage. Furthermore, if the length of the filler (B) is 50 microns or less, the fillers (B) do not intertwine with each other, resulting in poor coverage, and if the length of the filler (B) is 2000 microns or more, the filler ( B) The degree of mutual entanglement becomes excessive, causing problems in paint stability and painting workability. In order to maintain good coating stability and coating workability and obtain good coverage, it is desirable that the aspect ratio of the filler (B) is 3 to 5000.

The aqueous emulsion polymer (A) as a vehicle for the filler (B) is used to coat the surface of the object to be coated together with the filler (B) to protect the surface from contact with water, inorganic salts, etc. When a copolymer obtained by copolymerizing vinylidene chloride and/or vinyl chloride is used as the emulsion polymer (A), the adhesion, water permeability, moisture resistance, etc. of the coating film are improved.

However, from the viewpoint of weather resistance, it is desirable that the copolymer contains 90% by weight or less of the vinylidene chloride and/or vinyl chloride. Furthermore, in order to improve the weather resistance of the vinylidene chloride and/or vinyl chloride, it is desirable to copolymerize an alkyl acrylate and/or alkyl methacrylate (C) containing 1 to 12 carbon atoms in the alkyl group. For the water permeability and moisture resistance of the membrane, the alkyl acrylate and/or alkyl methacrylate (c) should be added in an amount of 45 parts by weight when the total of vinylidene chloride (a) and vinyl chloride (b) is 100 parts by weight. It is desirable that the content is less than part by weight. Furthermore, it is desirable to copolymerize α-β unsaturated carboxylic acid (d) in order to improve the adhesion to metal surfaces, especially non-ferrous metal surfaces such as zinc, but the amount of α-β unsaturated carboxylic acid is If it exceeds 30% by weight, the water resistance of the coating film will be poor.

〔Example〕

Example 1 (Aqueous emulsion polymer 1) Into a reactor equipped with a stirrer, thermometer, and condenser were added 600 parts by weight of water, 2 parts by weight of ammonium polyacrylate, 5 parts by weight of polyoxyethylene alkylphenol ether, and 3 parts by weight of higher alcohol sulfate. After heating to 75°C and mixing and dissolving, 5 parts by weight of ammonium persulfate was added, and a monomer mixture having the following composition was continuously added dropwise over 3 hours.

Styrene 200 parts by weight 2-ethylhexyl acrylate 175 β-hydroxyethyl methacrylate l Q n methacrylic acid
5 After the above monomer mixture was added dropwise, the mixture was further heated to 75°C for 3 hours and stirred with N, and then cooled to room temperature to obtain an aqueous emulsion polymer 1 with a viscosity of 1500 Cps and a solid content of 40% by weight.

Example 2 (Aqueous Emulsion Polymer 2) 600 parts by weight of water, 7 parts by weight of rosin soap, and 3 parts by weight of alkyl phosphate were charged into a reactor similar to Example 1, and heated to 60'C to mix and dissolve. , 3 parts by weight of sodium perborate, and 2 parts by weight of sodium hyposulfate, and then a monomer mixture having the following composition was continuously added dropwise over 3 hours.

Vinylidene chloride 400 parts by weight n-butyl acrylate 9 On After the above monomer mixture was added dropwise, the mixture was further heated at 60°C for 2 hours and 80°C for 1 hour with N stirring, and then cooled to room temperature to give a mixture with a viscosity of 700 cps and a solid content of 50% by weight. Aqueous emulsion polymer 2 is obtained.

Example 3 (Aqueous emulsion polymer 3) A monomer mixture having the following composition was used in the same manner as in Example 2 to obtain a viscosity of 75 Qc.
ps, an aqueous emulsion polymer 3 having a solid content of 55% by weight is obtained.

Vinylidene chloride 400 parts by weight Vinyl chloride 20o Ethyl acrylate
90 Example 4 (Aqueous emulsion polymer 4) Polymerization was carried out in the same manner as in Example 2 using a monomer mixture having the following composition, and then the pH was adjusted to 8 with ammonia and the viscosity was adjusted to 4000.
cps, aqueous emulsion polymer with a solid content of 60% by weight 4
get.

Vinylidene chloride 320 parts by weight Vinyl chloride 15o 2-ethylhexyl acrylate 100 Acrylic acid 2
0 Example 5 (Aqueous Coating Composition 1) Using the aqueous emulsion polymer 1 obtained in Example 1, the following composition was mixed in a homomixer to obtain aqueous coating composition 1.

Water 22 parts by weight Ethylene glycol monobutyl ester 3 n Antifoaming agent (silicon type) 0.2 Methoxycellulose 1,87/rock wool * lO Rust-preventive pigment
3. Calcium bicarbonate 15. Aqueous multilayer polymer 1. 45. Rock wool has an average diameter of 5 microns and an average length of 200 microns.

Example 6 (Aqueous coating composition 2) Using the aqueous emulsion polymer 2 obtained in Example 2, the following composition was mixed in a homomixer to obtain an aqueous coating composition 2.

Water 26.5 parts by weight Propylene glycol 3.5 Sorbitan alkyl ester 0.3 Antifoaming agent (silicon type) 0.2 Ethoxy cellulose 1.5 〃Polyester short fibers* 6 Rust-preventing pigment 3 〃Calcium bicarbonate 14 Water-based engineered mullion Polymer 2 45 Umbrella: Polyester staple fibers with a thickness of 2 denier and a length of 0.4+nm.

Example 7 (Aqueous Coating Composition 3) The polyester short fibers of Example 6 were replaced with an average diameter of 0.4
Aqueous coating composition 3 is obtained using short potassium titanate fibers with an average length of 50 microns.

Example 8 (Aqueous Coating Composition 4) Using the aqueous emulsion polymer 3 obtained in Example 3, the following composition was mixed in a homomixer to obtain an aqueous coating composition 4.

Water 22 parts by weight Ethylene glycol monobutyl ether 3,5n dialkyl sulfosuccinate o, 2 Antifoaming agent (silicone type I
O, 3n meerschaum stone book 1
゜Anti-rust pigment 4 Calcium bicarbonate 15 〃Aqueous emulsion polymer 4 45 Ne: The average diameter of sepiolite is 3 microns, the average length is 150
It is micron.

Example 9 (Aqueous Coating Composition 5) Aqueous coating composition 5 is obtained by replacing the sepiolite of Example 8 with glass wool having an average diameter of 13 microns and an average length of 0.5zITn.

Example 10 (Aqueous Coating Composition 6) Aqueous coating composition 6 is obtained by replacing the sepiolite of Example 8 with phenolic resin fibers having an average diameter of 30 microns and an average length of 0.3 rLrn.

Example 11 (Aqueous Coating Composition 7) Using the aqueous emulsion polymer 4 obtained in Example 4, the following composition was mixed in a homomixer to obtain an aqueous coating composition 7.

Water 22 parts by weight Ethylene glycol monobutyl ether 3.5 Dialkyl sulfosuccinate 0.3 Antifoaming agent (silicon type) 0.2 Wollastonite IO Antirust pigment
4 Calcium carbonate f5tt aqueous emulsion polymer 4 45 Ratio: The average diameter of wollastonite is 5 microns.

Average length is 200 microns.

Example 12 (Aqueous Coating Composition 8) Wollastonite in Example 11 was replaced with an average diameter of 0.3
Aqueous coating composition 8 is obtained using fibrous basic magnesium sulfate with an average length of 30 microns.

[Practical test 1] Aqueous coating composition 1 prepared in Examples 5 to 12 above
The following practical tests were carried out on 8.

1. Preparation of test piece Water-based coating compositions 1 to 8 were applied to a 150 x 70 x 0.8 mm tan sheet plate (same material as the fuel tank), respectively.
C. and dried for 30 minutes to prepare test specimens 1 to 8 each having a coating film thickness of 300 microns. The test pieces 1 to 8 were left at room temperature for 7 days, and then tested.

2. Test method (1) Nut drop test M--4 Using a brass nut, the drop is 2 m, and each of the above test pieces 1 to 8, each weighing 3 kg, is held at an angle of 60' from the horizontal plane, and the surface of the test piece is Measure the maximum weight that can be dropped without exposing the surface of the material.

(2) Gravelometer test Using a JA-400 flying stone tester manufactured by Suga Test Instruments Co., Ltd., 500 g of No. 6 crushed stone was sprayed onto the surfaces of the above test specimens 1 to 8 at an air pressure of 51 cg/aJ. The above spraying is performed three times.

(3) Salt water spray test (S S T,) Using a 5T-11L-180 salt water spray tester manufactured by Suga Test Instruments Co., Ltd., 5 W / V% saline solution is sprayed onto the sample surface.

The sample is (2) Test piece 1 after gravelometer test.
~8. The evaluation is performed according to JISK-540O using test pieces 1 to 8 whose coating films were cut according to JISK-5400.

3. Test results The test results are shown in Table 1.

This is a comparative example in which rock wool was omitted from Table Gravity Ratio 1: Aqueous Coating Composition 1.

[Practical test 2] Aqueous coating composition 1 prepared in Examples 5 to 12 above
The following practical tests were carried out on 8.

1. Preparation of test piece Water-based coating compositions 1 to 8 were applied to a 150 x 70 x 0.8 mm iron plate (same material as the fuel pipe), and heated at 80°C for 30 minutes.
Test piece 9 - 300 microns thick after drying for minutes ↓
6 was produced. The test piece is left at room temperature for 7 days, and then Practical Test 2 is conducted.

2. Test method (1) Nut drop test Carry out in the same manner as [Practical Test 1].

(2) Gravelometer test Carry out the same procedure as [Practical Test 1].

(3) Salt spray test (SST) Carry out the same procedure as [Practical Test 1].

3. Test results The test results are shown in Table 2.

(The following is a blank space) Table *Ratio 2: This is a comparative example in which rock wool was omitted from water-based coating composition 1.

〔Effect of the invention〕

As shown in Tables 1 and 2, the aqueous coating composition of the present invention has extremely good abrasion resistance (chipping resistance) and chemical resistance compared to the comparative example in which no filler is mixed. This makes it extremely suitable for use as a protective coating for the surface of automobile underfloor components. Furthermore, since the coating composition used in the present invention is water-based, there is no toxicity or fire risk.
Extremely safe and easy to handle.

Claims (1)

[Claims] 1. Mono-carbon having one vinyl group or vinylidene group
An aqueous emulsion polymer (A) consisting of one or more ethylenically unsaturated monomers and a diameter of 0.2 to
It is characterized in that an aqueous coating composition containing as an essential component one or more types of organic or inorganic fibrous or acicular filler (B) having a size of 100 microns is applied to the surface. An automobile underfloor member 2, wherein the underfloor member is a fuel pipe disposed under the floor of the automobile; an automobile underfloor member 3 according to claim 1, wherein the underfloor member is a fuel tank disposed under the automobile floor; Automobile underfloor components described in scope 1