KR100388894B1 - Process for Manufacturing High Lubricant Anti-Finger Printer Resin having excellent Appearance and Lubricating Property - Google Patents

Abstract

The present invention is to provide a method for producing a fingerprint coating for producing a fingerprint-treated surface steel sheet excellent in lubricity and surface appearance used in home appliances, the present invention is 2 to 40 for the ethylenically unsaturated monomer capable of radical polymerization The polymerization initiator is used to prepare a urethane-modified acrylic copolymer resin solution synthesized using 0.1 to 5% by weight based on the ethylenic monomer capable of radical polymerization, and to improve the copolymer alone or the curing reaction. (Carbodiiminde) relates to a method for producing an anti-fingerprint solution, characterized in that the addition of 2 to 15% by weight.

Description

Process for Manufacturing High Lubricant Anti-Finger Printer Resin having excellent Appearance and Lubricating Property}

The present invention relates to a method for producing a zinc-plated steel sheet anti-fingerprint solution excellent in lubricity and anti-fingerprint.

In general, the anti-finger steel sheet is a steel sheet having a triple structure (shown in FIG. 1) applied to a phosphate-treated galvanized steel sheet as a thin film and is mainly applied to indoor electronic products such as home appliances and computer cases.

Electroplated galvanized steel sheet with phosphate coating is hard to be erased in the post process if finger prints are left on the hand, and the appearance is worse even after assembling into the final product. The thin resin coating process prevents fingerprints and improves the surface appearance. Conventionally, anti-fingerprint resin liquid and lubricated steel sheet resin liquid have been marketed separately, but as the number of assemblies undergoing severe processing increases, TCE (trichloro) having high vaporization property is applied in the step of applying and processing lubricating oil and removing lubricating oil. With the use of ethane, the interest and regulation on the global environment are intensifying. Therefore, high lubrication or fingerprint resin is required that satisfies anti-fingerprint and high lubricating activity and has an excellent surface appearance.

Korean Patent Application Publication No. 4-14191, which introduces a technique in the related art, forms an organic composite film in which chromate-plated steel sheet is added with an aqueous organic resin and colloidal silica, and has improved anti-fingerprint and corrosion resistance. In this article, it is stated that in order to improve severe processability, paints in which wax was added to organic coatings were developed.

However, according to the prior art, when lubricating oil is used in the temperature range from room temperature to near the glass transition temperature of the resin film, the press formability is good, but continuous molding without lubricating oil is particularly effective in the frictional heat during processing under extreme processing conditions. The mold temperature rises and the steel surface temperature rises to 130 ℃.

Accordingly, if the resin is not converted to thermosetting and the glass transition temperature of the resin is not high, the resin is detached between the processing die and the mold and adhered to the mold as small fragments, so that the resin fragments of the mold are transferred to the steel sheet during subsequent processing. Defects will occur.

Accordingly, an object of the present invention is to provide a lubricating film having excellent workability during continuous press and severe processing, and to provide a anti-fingerprint resin composition for lubricating surface treatment and a method of manufacturing the same.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory cross-sectional view of a coating layer structure of a to-fin steel sheet coated with a to-fin resin composition according to the present invention.

The present invention is basically a new paint system that can secure the physical properties of the anti-fingerprint steel plate and the lubricated steel sheet, that is, in the anti-fingerprint resin solution for surface treatment by coating the phosphate-treated galvanized steel sheet, the galvanized steel sheet The anti-fingerprint coating solution is usually applied in a thickness of about 1 μm, and the anti-fingerprint coating solution is obtained by finely adding an ethylenically unsaturated monomer capable of radical polymerization, urethane resin and emulsifier with a homer mixer and integrating the average of the final aqueous resin dispersion. The present invention relates to an anti-fingerprint resin composition having excellent lubricity and surface appearance made of a water-dispersed urethane-modified acrylic copolymer having a particle diameter of 50 nm or less.

Although the physical properties of the steel door and the lubricated steel are similar to each other, they have properties that are opposite to each other in terms of lubricity and glossiness or surface appearance. In order to solve the above problems, the present invention uses a resin having a high molecular weight and high processability, but it is difficult to solve such quality problems with one type of resin. Or, the inventors have invented a resin synthesis technology that chemically bonds.

Commonly used cold rolled steel coating resins include acrylic resins and urethane resins. Acrylic resins are effective in solvent resistance, alkali resistance, gloss, weather resistance, and rubbing resistance, but the resin itself has a high hardness, so the stretching of the resin during processing Not only is it difficult, but also has poor quality defects. In order to satisfy these defects, it was found that improvement can be achieved by adding a small amount of urethane resin which can improve the workability and corrosion resistance to the acrylic resin for steel sheet coating.

Urethane resins have excellent properties in elongation and adhesion, but have poor physical properties in weatherability and alkalinity, and are expensive compared to other resins. Therefore, when acrylic resins and urethane resins are mixed in an appropriate ratio, they are required for high lubricity. It was found that the quality can be secured.

Injecting these two types of resin solution may cause problems such as gelling and precipitation of the solution. To prevent this, it is possible to use a high-speed dispersion method during stirring or to modify and copolymerize the urethane resin during the acrylic resin polymerization reaction.

The manufacturing method of this resin liquid includes the cold blending method and the modification method at the time of synthesis | combination. First of all, the modification method in the synthesis relates to the production of urethane-modified acrylic copolymer, which is a method of producing a water-dispersible resin liquid obtained by radical polymerization using an ethylenically unsaturated monomer capable of radical polymerization, a urethane, an emulsifier polymerization initiator, and water. The particle size of the mixed monomer to be dropped is finely emulsified with a homer mixer, and then dropwise added so that the average particle diameter of the final aqueous resin dispersion is 50 nm or less.

Recently, organic solvent-based paints have been changed from water-based paints to water-based paints, especially from the viewpoint of effective use of resources. However, in the case of conventional water-based paints, water that lacks affinity with resin evaporates to form a coating film. Compared to solvent type paints, the densities are poor, and among the properties required for paints, water resistance and adhesion to the lower surface are bad.

Therefore, in order to solve these defects, the above-mentioned defects are compensated for by adding an aqueous urethane resin to the aqueous acrylic emulsion resin or reacting in the molecular structure of the aqueous emulsion resin.

However, it is not preferable to add urethane resin to aqueous acrylic emulsion, since the coating liquid state causes problems such as separation and gelation, and the use of surfactants to solve this problem adversely affects water resistance and adhesion to the lower limbs.

Monomers used in this resin solution include methyl acrylate, ethyl acrylate, butyl acrylate, 2 ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, 2 ethylhexyl methacrylate, octyl methacrylate and stearic. Methaacrylate, cyclohexyl methacrylate alkyl ester ketaacrylate, vinyl propionate, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, idaconic acid, N-methyroacrylamide, hydroxyethyl acrylate, vinyltoluene, ethylene Grichol diacrylate, diacryl phthalate, divinylbenzene, etc. can be used.

Generally, acrylic acid, methacrylic acid, and idaconic acid may be used in combination with an ethylenically unsaturated monomer during radical polymerization in order to improve polymerization stability in aqueous solution. The amount is preferably 2 to 20% by weight, and the amount is less than 2% by weight. If the polymerization stability and viscosity changes over time, the viscosity stability is bad, on the contrary, if the weight is more than 20% by weight, the water resistance of the film is reduced, so it is good to limit the content.

Moreover, in order to improve the fluidity | liquidity, drying property, and stability of an aqueous resin liquid, acrylamide, N-methyryl acrylamide, hydroxypropyl acrylate, and methacrylate can also be used. The urethane resin used in the present invention is obtained by chain extension of a conventional urethane prepolymer obtained by reacting a polyol and a polyisocyanate with a low molecular weight compound having two or more active hydrogens, wherein the urethane prepolymer can be radically polymerized. It is preferable to use 2-40 weight% with respect to an ethylenically unsaturated monomer. If the content of the polyurethane resin is 40% by weight or more, the reactivity with the ethylenically unsaturated monomer capable of radical polymerization is not good, and the unsaturated ethylene monomer is unreacted to generate agglomerates, which is not preferable because of poor polymerization stability.

Acrylamide, N-acrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, etc. can be used in order to improve the stability at the time of fluid dryness adjustment resin adjustment. Moreover, in order to give a crosslinked structure of a film, ethylene glycol dimethacrylate, diacryl phthalate, divinylbenzene, etc. can be used, but for the purpose, 1 type, or 2 or more types can be mixed and used. The content may be used in an amount of 0.1 to 10% by weight based on the total monomers. If the content is less than 0.1% by weight, the water resistance is poor.

In addition, reactive emulsifiers used in the present invention include anionic or non-ionic emulsifiers having at least one unsaturated double bond capable of radical polymerization in a molecule, for example, sulfonic ester (HENKEL). TREMLF-40, SAN-NOPCO's SN-Emulsifier 702, and SANYOKASEI's ELEMINOL JS-2).

The curing agents applicable to this resin include various curing agents such as epoxy, melamine resin, aziridine series, carbodiimide, etc. However, it is preferable to use a small molecular weight in order to give many reactors at the same content. Since the reaction is performed at a high baking temperature, the reaction temperature is preferably 150 ° C. or higher.

In addition, the melamine resin must be made to have good curing reaction even at low baking temperature by using an acid catalyst in order to increase the low temperature reactivity, and it is preferable to use cymel325 having good room temperature reactivity in melamine system. Both epoxy and melamine react at high temperature. Since the reaction temperature is high or the reaction time is long, it has a drying characteristic that can react.

In addition, as a curing agent that can react at room temperature and low temperature, there are aziridine-based and carbodiimide-based, among which the aziridine-based structure has a trifunctional group rather than a monofunctional group. In other words, since it has three aziridine reactors per molecule, even if the amount of the hardener is added, it is more advantageous in terms of physical properties since three subjects are combined in one molecule. In the case of the aziridine curing agent, it should be applied in a two-part type (part A and part B, which are separated from Part A and mixed immediately before use), but in a one-part type, aziridine molecular ring is opened under acidic and basic conditions. This is because it is decomposed, and in the case of mixing with the main resin, it is preferable to use it within 1 to 2 days.

In addition, the aziridine system should be handled as toxic and should be used in a limited amount because the effect of improving the physical properties is small even if the amount used is small, and if the paint is not used after mixing, the initial use of aziridine for reuse It can be replenished as much as you put in.

Therefore, in order to solve these problems, the present patent uses high molecular weights to increase the molecular weight of the urethane-modified acrylic resin to represent all the physical properties of the coating material without a curing reaction. Can be used.

The curing mechanism of the curing agents are all the mechanism of reacting with the oxygen of the carboxyl group by attacking the hydrogen of the carboxyl group of the A sub resin, the typical name of the aziridine system is tetramethylomethane-tri-aziridinylpropionate (Tetramethylomethane-tri -aziridinylpropionate (TEMA) and its structure is composed of three aziridine reactors and the curing reaction is made by reaction with carboxyl (-COOH) groups.

And, the structural formula of carbodiimide is R ₁ -N = NR ₂ and the curing reaction proceeds by the reaction of carbodiimide and carboxyl groups, the reaction can be described as follows. R is represented by an alkyl group (-CnH2n + 1).

In the present invention, when a curing reaction of the resin is required, it is preferable to use carbodiimide, which is not toxic to the environment and can be safely handled. The curing agent is used with the carboxylic acid of the urethane-modified acrylic copolymer and the acrylethylene copolymer. The reaction forms an N-Acyl Urea bond. The content is suitably about 2 to 15% by weight, most preferably 5 to 10% by weight. If the content is less than 2% by weight, the degree of curing is insufficient and at least 15% by weight there is no increase in the degree of curing.

In order to improve the quick-drying and applicability of the aqueous solution, it is preferable to use an alcohol-based solvent that has affinity with water. Most preferably, n-Butanol is the best, but it is not good at the time of application because of the high smell. not. Therefore, in the present invention, the anti-fingerprint solution functions to improve the wettability of the solution when the resin is applied to the steel sheet, and during baking, the volatility is good even at low temperature, so that it does not remain in the coating film after drying. Therefore, in the present invention, it is preferable to use a solvent having a low molecular weight methanol, ethanol and isopropyl alcohol system. In addition, the amount to be added is also good 2 to 10% by weight with respect to the amount of the conductive material, preferably 3 to 5% by weight.

( Example)

In a reactor equipped with a stirrer, a thermometer, a dropping system, and a reflux reactor, a reactive emulsifier and a polymerization initiator were put first, and nitrogen was purged. The chemicals shown in Table 1 were emulsified finely with a high speed stirrer in advance, and then the inside of the stirrer was raised to 80 ° C., followed by dropping 5 minutes later. After dropping the dropping amount for 2 hours, the dropping amount was adjusted, and then matured at 80 ° C. for 2 hours for cooling, and then the pH was adjusted to 8.5-9.5 with ammonia water (28%). Solid content at this time was 40%, and the viscosity was 850 cps.

The resin solution, which was synthesized as described above and neutralized with the prepared copolymer resins (Samples I ~ III) and dimethylethanolamine, and the urethane resin mixed with the resin solution, was coated on a phosphate-treated galvanized steel plate and reached the plate temperature up to 80 ° C. It was dried to prepare a steel plate and the film thickness was adjusted to 1 micrometer.

Physical properties were evaluated for fingerprint resistance, appearance, alkali resistance, solvent resistance, tentacle fingerprint resistance, and corrosion resistance, and the contents thereof are listed in Table 2. Appearance was evaluated using the color difference meter.

(Fingerprint resistance)

Anti-fingerprint was divided into the indexes listed below by pressing the human fingerprint on the steel sheet manufactured according to the above method for 3 seconds and the accuracy of the fingerprint with the naked eye. Here, in order to use fingerprinting for actual sales, it should be at least 3 points. In the embodiment of the present invention based on the following criteria, a high fingerprinting measurement result of three specimen average ratings 5 was obtained (see Table 2).

No fingerprint traces at all: Rating 5

Almost unknown fingerprint trace: Rating 4

If you look closely you can see fingerprint traces: Rating 3

Fingerprint traces appear: Rating 2

Fingerprint traces are well seen.

(Scratch resistance)

Processability and scratchability were marked according to the coin trace when scratched with a coin, and the traces of coin marks were divided into the indicators listed below. In fact, in order to use machinability in practice, a score of 3 or more is required.

I can't tell any scratches with a coin

Almost no evidence of coin scratches: rating 4

If you look closely you can see the scratches with a coin: Rating 3

Marking Scratches with Coins: Rating 2

Good at scratching with a coin: Rating 1

(Alkali resistance)

After preparing the steel sheet based on the above standards, the state of the coating film after immersion for 10 minutes in 50% aqueous solution of 5% by weight caustic soda was visually observed. In fact, in order to use alkali resistance in actual operation, the score should be at least 3 points.

Discoloration is unknown at all: Rating 5

Almost no discoloration: rating 4

Discoloration can be seen by careful observation: Rating 3

Discoloration and peeling traces appear: Rating 2

Discoloration and peeling traces can be seen well: Rated1

(Solvent resistance)

After preparing the steel sheet based on the above standards, the state of the coating film after reciprocating 10 times by applying a constant force to the gauze was applied to the gauze was visually observed. In fact, in order to have good contentability, the score should be at least 3 points.

Discoloration traces are unknown at all: Rating 5

Almost no color change trace: Rating 4

Discoloration traces when observed well: Rating 3

Discoloration is visible: Rating 2

Discoloration is clearly visible: Rating 1

The method of evaluating the tentacle fingerprint resistance is primarily to measure the glossiness of a high lubricated steel sheet, and then apply petroleum jelly to the same steel sheet again to remove residual petrolatum on the steel sheet. By measuring the glossiness again, it can be evaluated by calculating the difference in glossiness before and after the glossiness measurement. At this time, if there is a large difference in glossiness, the tentacle fingerprint resistance is poor. On the contrary, a small difference means that the tentacle fingerprint is good. In fact, in order to have a good tentacle fingerprint resistance, the score should be 3 or higher.

Glossiness difference before and after petroleum jelly is less than 2: Rating 5

Glossiness difference before and after petroleum jelly is 2 ~ 4: Rating 4

Glossiness difference before and after petroleum jelly is 4 ~ 6: Rating 3

Glossiness difference before and after petroleum jelly is 6-8: Rated 2

Glossiness difference before and after petroleum jelly is more than 8: Rating 1

According to the above criteria, the specimens under the conditions of Specimen I, II, and III in Table 1 were further subdivided and divided into Inventive Materials (A, B, C), (D, E), and (F, G), respectively, to 10 wt. Table 2 shows the results obtained by applying the resin solution added as%, wax 5% by weight, and 3% by weight of the wetting agent to a galvanized steel sheet and then subjecting to the above-mentioned evaluation criteria and criteria.

As can be seen from Table 2, the surface-treated steel sheet having excellent surface lubricity, such as anti-fingerprint, tentacle fingerprint, and scratch resistance, scratch resistance, etc., and both solvent and alkali resistance according to the products of the present invention. This could be obtained.

As described above, the resin solution of the present invention enables to manufacture and supply excellent surface treated steel sheets, particularly anti-fingerprint steel sheets, as well as lubricity and surface appearance.

Claims (3)

In the manufacturing method of anti-fingerprint resin solution for surface treatment by coating on phosphate-treated galvanized steel sheet, anti-fingerprint coating composition is usually coated on the galvanized steel sheet within about 1㎛, and this anti-fingerprint coating composition is capable of radical polymerization. Lubricity and surface appearance, characterized in that the urethane resin and emulsifier are finely integrated with an ethylenically unsaturated monomer, an urethane resin, and made into a water-soluble urethane-modified acrylic copolymer in which the average particle diameter of the final aqueous resin dispersion is 50 nm or less. Method for producing this excellent anti-finger resin solution The urethane resin is 2 to 40% by weight based on the radically polymerizable ethylenically unsaturated monomer having a urethane prepolymer chain-extended with a low molecular compound having at least two active hydrogens usually obtained by reacting a polyol and a polyisocyanate. %, Or a polymerization consisting of any one or more of t-butylperbenzoate, lauryl perbenzoate, benzoyl peroxide, t-butylhydroperoxide, azobisisobutyronitrile, azobisdimethylbutyronitrile and the like A method for producing an anti-fingerprint solution having excellent lubricity and surface treatment appearance, comprising urethane-modified acrylic copolymer resin solution synthesized using 0.1 to 5 wt% based on the ethylenic monomer as possible. 3. The lubricity and surface treatment appearance according to claim 1 or 2, wherein carbodiimide is added in an amount of 2 to 15% by weight in order to enhance the curing reaction alone or in the copolymer. Method for producing excellent anti-finger resin solution.