JPH0812920A - Resin composition for lubricating surface treatment - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. which imparts excellent lubricity, fabricability, etc., to a coated surface by compounding fine polymer particles having specified particle sizes and obtd. by polymerizing a specific monomer mixture with a nonionic surfactant. CONSTITUTION:Fine polymer particles having particle sizes of 0.2-2mum are produced by copolymerizing a vinyl monomer component mainly comprising styrene and/or methyl methacrylate, a cross-linking monomer copolymerizable therewith (e.g. divinylbenzene), and a functional monomer (e.g. 2-hydroxyethyl acrylate). The resin compsn. is obtd. by compounding the particles with a nonionic surfactant. Suitable examples of the surfactant are a polyoxyethylene alkyl(phenyl) ether and a polyoxyethylene fatty acid ester. The compsn. is applied to the surface of a metallized compsn. coated with iron, zinc, etc., to smooth the surface.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resin composition for lubricating surface treatment. More specifically, the present invention relates to a resin composition for lubricating surface treatment, which imparts lubricity, molding processability, and high rustproofness to a coated surface and is excellent in coating property on a metal surface.

[0002]

2. Description of the Related Art Conventionally, metal sheets such as cold-rolled steel sheets and galvanized steel sheets used for home appliances and automobile thin plates have been subjected to forming processing such as pressing to obtain products. A lubricant such as press oil is used in this molding process, and after processing, it is removed using a chlorofluorocarbon-based solvent in a degreasing process. For this reason, the number of processes is increasing, and the use of solvents whose usage regulations are becoming stronger is being continued.

Under these circumstances, there has been proposed a functional surface-treated steel sheet having a lubricated surface which can cope with labor saving in the forming process and regulation of solvent use. These steel sheets have a surface coated with a composition containing an organic resin as a main component and imparting lubricity, and can be formed without the use of a lubricant such as press oil, and the subsequent degreasing step can be performed. It is a surface-treated steel plate that is not required. In addition, this steel plate is required to have rust resistance, solvent resistance and the like which are general performances of a metal steel plate.

For example, there are techniques disclosed in Japanese Patent Publication No. 51-3702, Japanese Patent Laid-Open No. 62-289274, Japanese Patent Laid-Open No. 60-221450, etc., all of which are rust preventive properties, lubricity and molding processability. All of these were not satisfactory techniques. To solve these problems, Japanese Patent Application No. 6-2404
The technique of Japanese Patent Laid-Open No. 9-93, that is, a method of using a composition containing crosslinked organic particles having a particle size in a specific range was proposed. According to this technique, it is possible to manufacture a surface-treated steel sheet having required performance. However, depending on the manufacturing conditions (coating method, temperature, etc.), uneven coating may occur at the time of finishing, or spots appearing on the coated surface may appear, resulting in a decrease in surface state uniformity.

[0005]

DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art, imparts basic performance as a lubricated surface-treated steel sheet, improves coatability on a metal surface, and provides a uniform surface condition. A resin composition for producing a surface-treated steel sheet having

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the above problems, and by adding a nonionic surfactant as an additive to polymer fine particles having a crosslinked structure, It was found that good coating properties and coatability can be imparted, and the present invention has been completed.

That is, the present invention comprises a vinyl monomer containing styrene and / or methyl methacrylate as a main component, a crosslinkable monomer copolymerizable therewith and a functional monomer, and obtained by polymerization. The present invention relates to a resin composition for lubricating surface treatment, which comprises the polymer fine particles having a particle diameter of 0.2 to 2 μm and a nonionic surfactant.

The present invention will be described in detail below. In the present invention, a vinyl monomer containing styrene and / or methyl methacrylate as a main component is used. As the vinyl monomer other than styrene and methyl methacrylate, an aromatic monomer such as α-methylstyrene or vinyltoluene is used. Vinyl compounds, methyl acrylate, ethyl (meth) acrylate, (meth)
(Meth) acrylic acid esters such as butyl acrylate,
It is possible to use vinyl esters such as vinyl acetate and vinyl propionate, vinyl cyan compounds such as (meth) acrylonitrile, and vinyl halide compounds such as vinyl chloride and vinylidene chloride.

The amount of styrene and / or methyl methacrylate which is the main component depends on the vinyl monomer which contains styrene and / or methyl methacrylate as the main component from the viewpoint of blocking property and lubricity of the obtained particles. A mixture containing a crosslinkable monomer copolymerizable with and a functional monomer (hereinafter,
These are referred to as a monomer mixture), and are preferably contained in an amount of 80% by weight or more, more preferably 90% by weight or more.

As the crosslinkable monomer used here,
Examples thereof include monomers having two or more polymerizable unsaturated bonds in one molecule such as divinylbenzene, ethylene glycol di (meth) acrylate, and trimethylolpropane trimethacrylate. The crosslinkable monomer is preferably 0.5 to 20% by weight, more preferably 1
10 to 10% by weight, most preferably 2 to 5% by weight are suitable. If the amount of the crosslinkable monomer is less than 0.5% by weight, the resulting particles have a low crosslinking density, so that sufficient film strength cannot be obtained, which is not preferable. Further, if it exceeds 20% by weight, aggregates are likely to be generated, and the polymerization itself does not proceed smoothly, which is not preferable.

Further, for the purpose of stabilizing the emulsion and the like, unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, itaconic acid and the like, unsaturated sulfonates such as sodium styrene sulfonate, 2 -(Meth) acrylic acid esters such as hydroxyethyl (meth) acrylate and glycidyl (meth) acrylate,
Alternatively, it is desirable to copolymerize a functional monomer such as (meth) acrylamide or N-methylol (meth) acrylamide. The amount of the functional monomer used is preferably 20% by weight or less, more preferably 10% by weight or less, based on the monomer mixture. 20 functional monomers
If it is used in an amount exceeding the weight percentage, aggregates are likely to be generated and the polymerization itself does not proceed smoothly.

As the emulsifiers used at the same time, anionic surfactants such as sodium alkylbenzenesulfonate, sodium alkylsulfate, sodium dialkylsulfosuccinate, formalin condensate of naphthalenesulfonate, polyoxyethylene alkyl (phenyl) ether, ethylene oxide. -Nonionic surfactants such as propylene oxide block copolymer and sorbitan fatty acid ester are used alone or in combination. The amount used in that case is not particularly limited, but is usually preferably 0.1 to 10% by weight with respect to the monomer mixture.

The polymerization initiator may be any one used in ordinary emulsion polymerization, such as persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, and benzoyl hydroperoxide. Examples thereof include organic peroxides and azo compounds such as azobisisobutyronitrile. If necessary, it can be used as a redox initiator in combination with a reducing agent.

The production of polymer fine particles having a crosslinked structure is as follows.
It is carried out by an emulsion polymerization method using the above raw materials. Polymerization was carried out under a nitrogen purge at a polymerization temperature of 20 to 90 ° C. with a crosslinkable monomer,
The mixture of monomers containing a functional monomer is dropped at once, dividedly, or continuously. Also, the polymerization is divided into two stages,
In the first step, a seed emulsion is prepared in the presence of the above-mentioned surfactant and polymerization initiator, and in the second step, the monomer mixture containing the above-mentioned crosslinkable monomer is added to perform polymerization. By repeating the “legal process”, it is possible to easily obtain large particles which are difficult to obtain by one polymerization.

The polymer fine particles having a crosslinked structure of the present invention are vinyl monomers containing styrene and / or methyl methacrylate as a main component, and a crosslinkable monomer copolymerizable therewith.
It is obtained by emulsion polymerization of a monomer mixture containing a functional monomer, and the particle size is preferably 0.2 to 2 µ, more preferably 0.5 to 1.5 µ. If it is less than 0.2 μm, the lubricity and solvent resistance tend to be insufficient, and if it exceeds 2 μm, agglomerates are likely to occur during production and the polymerization itself does not proceed smoothly.

As described in Japanese Patent Application No. 6-24049, the polymer fine particles obtained by the above method should be used in the same concentration or diluted with water to obtain a surface-treating resin composition. It is possible to impart surface lubricity and other properties, but it is extremely difficult to apply it uniformly on the metal surface.

Therefore, in order to solve this problem, in the present invention, a nonionic surfactant is further added as an additive. The degree of polymerization of the additive, the HLB value, etc. are not particularly limited, but the degree of polymerization of the ethylene oxide chain is 5 to 10, the HLB is HLB.
Those of 10 to 16 are preferable. Examples of the above nonionic surfactants include polyoxyethylene alkyl (phenyl) ethers and polyoxyethylene fatty acid esters.

The amount of addition is 0.5 to 2 with respect to fine polymer particles (converted to solid content, measuring method: 105 ° C.-3 hours).
0% by weight is preferable, more preferably 2 to 10% by weight,
Most preferably, 3 to 7% by weight is suitable. Although the mechanism of manifestation of the effect of these additives is not always clear, it is presumed that the excellent wettability of the treatment liquid with respect to the metal surface is improved due to the excellent interfacial tension lowering ability.

The metals usable in the resin composition for lubricating surface treatment thus obtained are iron, steel, alloy steel, zinc,
At least one selected from zinc alloys may be used. Further, it can also be used for a metal coating coated with at least one selected from iron, steel, alloy steel, zinc and zinc alloy.

The coating method is not particularly limited, but is generally applied to the metal surface as follows. That is, it suffices to apply 0.5 to 6 g / m ^{2 on} the surface of the metal material by a method such as brush coating, spray coating, roll coating, or dipping, and dry at a temperature of room temperature or higher for several seconds to several minutes. The drying temperature is preferably room temperature to 500 ° C, more preferably 100 to 3
It is 00 ° C.

[0021]

EXAMPLES In order to more specifically describe the present invention,
Examples and comparative examples will be described, but the present invention is not limited to these examples. In the following, all parts and% are parts by weight and% by weight. Polymerization Example 1 A separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 250 parts of water and 0.01 sodium lauryl sulfate.
Part of the mixture was charged, and the temperature was raised to 70 ° C. under nitrogen with stirring. Keeping the internal temperature at 70 ° C, add 2 parts of potassium persulfate as a polymerization initiator, dissolve, and charge a mixed monomer of 2 parts of styrene, 0.02 part of acrylic acid and 0.01 part of divinylbenzene and react for 3 hours. did. After completion of the reaction, subsequently, an emulsified mixture prepared in advance by adding 200 parts of water, 1.5 parts of sodium lauryl sulfate to 297 parts of styrene, 3 parts of acrylic acid, 3 parts of acrylamide, and 12 parts of divinylbenzene under stirring was prepared. The reaction was carried out by continuously adding over 4 hours. After the addition was completed, the mixture was aged for 4 hours, and the polymer fine particles were cooled to room temperature and neutralized with 8% ammonia water to adjust the pH to 8.5. The obtained polymer fine particles had a nonvolatile content of 41.2% and a viscosity of 8 cps / 25 ° C. (BM type viscometer No. 1 rotor, rotation speed 60 rpm). The particle size measured by an electron microscope was 0.6.
It was 5μ.

Polymerization Example 2 Polymerization was carried out in the same manner as in Polymerization Example 1 in the first stage reaction, and subsequently, the second stage reaction was carried out in advance with 200 parts of water, 1.5 parts of sodium lauryl sulfate and 297 parts of methyl methacrylate, Acrylic acid 3 parts, acrylamide 3 parts, divinylbenzene 1
The emulsion mixture prepared by adding 2 parts with stirring was continuously added over 4 hours to carry out the reaction. After the addition is complete
After further aging for 4 hours, the polymer fine particles were cooled to room temperature and neutralized with 8% aqueous ammonia to adjust the pH to 8.5. The obtained polymer fine particles have a nonvolatile content of 41.0%,
The viscosity was 8 cps / 25 ° C. (BM type viscometer No. 1 rotor, rotation speed 60 rpm). In addition, the particle size measured by an electron microscope was 0.59μ.

Polymerization Example 3 Polymerization Example 1 was repeated except that divinylbenzene was omitted. The obtained polymer fine particles have a nonvolatile content of 4
1.1%, viscosity 9 cps / 25 ° C. (BM type viscometer No.
It was 1 rotor and the rotation speed was 60 rpm). The particle size measured by an electron microscope was 0.60 μm.

Polymerization Example 4 Polymer fine particles were obtained in the same manner as in Polymerization Example 1 except that 0.3 part of sodium lauryl sulfate and 0.12 part of acrylic acid were used in the first-step reaction of Polymerization Example 1. It was The obtained polymer fine particles had a nonvolatile content of 41.5% and a viscosity of 9 cps /
25 ° C (BM type viscometer No. 1 rotor, rotation speed 60r
pm). The particle size measured by an electron microscope was 0.13 μm.

Polymerization Example 5 Polymeric fine particles having a large particle size (theoretical particle size) were carried out in the same manner as in Polymerization Example 1 except that the amount of sodium lauryl sulfate was changed to 0.005 parts in the first-step reaction of Polymerization Example 1. :
2.5 μ) was tried, but the polymerization did not proceed smoothly,
The desired polymer fine particles were not obtained. Polymerization Example 1
Results of 5 are summarized in Table 1.

[0026]

[Table 1]

Example 1 100 parts of water, 100 parts of polymer fine particles of Polymerization Example 1 and polyoxyethylene lauryl ether (polymerization degree 6.5, H
LB: 14) A solution prepared by mixing 2 parts in advance was added, and the solution was applied on an electrogalvanized steel sheet with a bar coater so that the amount was 2 g / m ^2, and dried at an ambient temperature of 150 ° C. for 5 minutes. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Example 2 In the same manner as in Example 1, the polymer fine particles of Polymerization Example 2 were used for coating and drying. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Example 3 In the same manner as in Example 1, polyoxyethylene nonylphenyl ether (polymerization degree: 8, HLB: 1) was used as an additive.
2) 2 parts were applied and dried. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Example 4 In the same manner as in Example 3, the polymer fine particles of Polymerization Example 2 were used for coating and drying. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Comparative Example 1 A treatment liquid prepared by adding 100 parts of the polymer fine particles of Polymerization Example 1 to 100 parts of water was applied on an electrogalvanized steel sheet with a bar coater to 2 g / m ^2, and the temperature was 150 ° C. At ambient temperature of 5 minutes. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Comparative Example 2 In the same manner as in Comparative Example 1, the polymer fine particles of Polymerization Example 2 were used for coating and drying. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Comparative Example 3 In the same manner as in Example 1, the polymer fine particles of Polymerization Example 3 were used for coating and drying. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

Comparative Example 4 In the same manner as in Example 1, the polymer fine particles of Polymerization Example 4 were applied and dried. Table 2 shows the evaluation results of the obtained surface-treated steel sheet. In addition, there was no abnormality such as phase separation during the mixing process.

[0035]

[Table 2]

The evaluation was carried out as follows. (1) Solvent resistance: A gauze impregnated with petroleum benzine was subjected to a 10-way rubbing test by applying a load of 500 g. ○: No change △: Scratch is present ×: Elution

(2) Antirust property: A salt spray test according to JIS-Z-2731 was carried out for 500 hours to evaluate the white rust generation area. ○: White rust occurrence area is less than 5% △: White rust occurrence area is 5 to less than 20% × ... White rust occurrence area is 20% or more

(3) Lubricity: Measurement of dynamic friction coefficient Measured according to ASTM D-1894 ◯ ... 0.05 or less Δ ... 0.05 to 0.10 × ... more than 0.10.

(4) Formability: A high-speed cylindrical deep-drawing test was conducted, in which blank diameter = 96 mmφ, punch diameter = 40 mmφ,
Wrinkle holding pressure = 1 ton, deep drawing speed = 30 m / min
It carried out on condition of. The limiting aperture ratio at this time is 2.40. ○: Aperture stop, limit aperture ratio of 2.50 even aperture stop Δ: Aperture stop ×… No aperture stop

(5) Uniformity of coated surface: judged by visual inspection O: No uniform unevenness Δ: Coating unevenness ×: Significant coating unevenness

[0041]

INDUSTRIAL APPLICABILITY The present invention uses fine polymer particles of 0.2 to 2 μm and contains a surfactant so that the compatibility with the fine polymer particles is good and the surface of the steel sheet after drying is It becomes uniform, and a surface-treated steel sheet excellent in solvent resistance, rust resistance, lubricity, and formability can be obtained.

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Claims (5)

[Claims] 1. Particles obtained by polymerizing a vinyl monomer containing styrene and / or methyl methacrylate as a main component, a crosslinkable monomer copolymerizable with these, and a functional monomer. A resin composition for lubricating surface treatment, which comprises polymer fine particles having a diameter of 0.2 to 2 μm and a nonionic surfactant. 2. The vinyl monomer is α-methylstyrene,
Aromatic vinyl compounds such as vinyltoluene, methyl acrylate, ethyl (meth) acrylate, (meth) acrylates such as butyl (meth) acrylate, vinyl acetates such as vinyl acetate and vinyl propionate, (meth The composition according to claim 1, which is a vinyl cyanide compound such as acrylonitrile or a halogenated vinyl compound such as vinyl chloride or vinylidene chloride. 3. The crosslinkable monomer is a monomer having two or more polymerizable unsaturated bonds in one molecule, such as divinylbenzene, ethylene glycol di (meth) acrylate and trimethylolpropane trimethacrylate. The composition according to 1. 4. The functional monomer is (meth) acrylic acid,
Unsaturated carboxylic acids such as crotonic acid and itaconic acid, unsaturated sulfonates such as sodium styrene sulfonate,
The composition according to claim 1, which is a (meth) acrylic acid ester such as 2-hydroxyethyl (meth) acrylate or glycidyl (meth) acrylate, or (meth) acrylamide or N-methylol (meth) acrylamide. 5. The composition according to claim 1, wherein the nonionic surfactant is polyoxyethylene alkyl (phenyl) ether, polyoxyethylene fatty acid ester or the like.