KR20010086650A - Method of the manufacturing transcribed-sheet - Google Patents

Abstract

PURPOSE: A method for manufacturing a non-clear gravure transfer printed steel sheet is provided which not only has various superior physical properties compared with a general printed steel sheet but also omits top clear coating process without any separate adjustment for the working conditions of a general PCM color line. CONSTITUTION: The method for manufacturing a non-clear gravure transfer printed steel sheet comprises the steps of forming a chromate layer for preventing rust on the plating layer when a base steel sheet or a plating layer is formed; roll coating primer paint on the chromate layer, heating and drying the primer paint coated chromate layer so as to form a primer coating layer; transferring the gravure transfer paper using heat and pressure after putting a gravure transfer paper in which a thermosetting resin layer and a printing layer are sequentially formed on a base film layer of the primer coating layer; and releasing the base film layer of the gravure transfer paper, wherein the thermosetting resin layer is practically cured when the gravure transfer paper is transferred on the primer coating layer.

Description

Method of manufacturing a non-clear gravure transfer printed steel sheet {METHOD OF THE MANUFACTURING TRANSCRIBED-SHEET}

The present invention relates to a method for manufacturing a gravure transfer printed steel sheet, and more particularly, such as aluminum steel sheet, zinc-aluminum alloy hot-dip galvanized steel sheet, copper steel sheet, tin, chromium and nickel plated steel sheet, electroplated and hot dip galvanized steel sheet, etc. In order to prevent corrosion on coated steel sheet, it is applied to the coated chromate, and the gravure transfer paper is applied to the plated steel plate coated with prima in order to give a beautiful appearance to the upper layer in a continuous process. The present invention relates to a method for manufacturing a non-clear gravure transfer printed steel sheet for producing a color steel sheet by a transfer operation.

In general, printed steel sheets used as beautiful exterior materials are limited to patterns and colors because they are processed as PCM paints in line equipment of continuous production, and they are difficult to express variously, and are difficult to reproduce colors and sharpness due to blur of printing dots. There is a disadvantage of falling back. In order to make up for such drawbacks, this problem is usually improved by increasing the number of prints on the line equipment to give various patterns and colors or by efficient management of the work process. As a result, satisfactory effects are hard to expect.

Recently, in order to supplement the above problems, a lamina steel sheet product which laminates the printed film on a steel sheet after performing various printing on the film is also commercially available. There is a disadvantage that occurs in terms of environmental pollution.

On the other hand, the production technology of the color steel sheet using the transfer method is disclosed in, for example, Japanese Unexamined Patent Publication No. Hei 4-280994, Korean Unexamined Patent Publication No. 1998-73736.

However, this technology has a disadvantage in terms of economical efficiency because of the necessity of the process of coating the top clear to give the post-processing and UV resistance, solvent resistance, weather resistance, etc. of the product, and also the top clear paint and transfer coating film Due to its reactivity problem, there is a disadvantage that only a limited top clear paint should be applied.

The present invention has been proposed in view of the above points, and an object of the present invention is to provide superior physical properties compared to general printed steel sheets while omitting top coat clearing process in the state as it is without any adjustment for general PCM color line working conditions. The present invention provides a method for manufacturing a non-gravure gravure transfer printed steel sheet.

The present invention to achieve the above object,

In the method of continuously manufacturing gravure transfer printed steel sheet in the PCM line, if a known base steel sheet or plated layer is formed, forming a chromate layer for rust prevention on the plated layer, by rolling a primer coating on the chromate layer and heating And drying to form a primer coating layer, transferring the gravure transfer paper on which the at least the curable resin layer and the printing layer are sequentially formed on the primer coating layer by heat and pressure, and peeling off the base film layer of the gravure transfer paper. Provided is a method of manufacturing a non-clear gravure transfer printed steel sheet, comprising the steps of:

The curable resin layer is substantially cured when the transfer coating film is transferred onto the primer coating layer.

Hereinafter, the present invention will be described in detail.

As the base steel sheet, most of the known ones such as aluminum steel sheet, zinc-aluminum alloy hot dip galvanized steel sheet, copper steel sheet, tin, chromium and nickel plated steel sheet, and galvanized and hot dip galvanized steel sheet are applicable.

The chromate treatment step is a step for improving the corrosion resistance, smoothness, adhesion of the primer (undercoat) coating to the steel sheet, and the coated chromate layer is preferable.

The primer coating layer functions to improve the adhesion between the steel plate surface and the transfer film and, in some cases, to provide a background color of the transfer coating layer (transfer pattern). The primer coating layer is in an inseparable relationship with the transfer coating layer formed thereon. If there is any undesirable difference in the properties of the primer paint and the transfer coating, the adhesion between the coating layers, the coating hardness, and the processing time Problems such as cracking of the coating layer and yellowing due to ultraviolet rays may occur. In addition, the primer coating is coated on the steel sheet and there is no bubble generation during drying by hot air in the post-process for curing, it is necessary to use a good adhesion to the transfer coating and workability, weather resistance, corrosion resistance.

Gravure transfer paper printed the desired pattern on the base film, and if transferred to the steel plate coated with a primer by heat and pressure, it is possible to produce colored steel sheets of various patterns. The transfer process of gravure transfer paper generally requires a post-transmission topcoat coating process to impart the surface protection and high contrast of the transfer coating film. However, the present invention has a great feature in simplifying the process by omitting the topcoat clearing process. This can be achieved by forming a curable resin layer on the printing layer capable of performing the above-described function of the top coat film (top coat clear) on the gravure transfer paper.

For this reason, the gravure transfer paper applied to the present invention is required to be a gravure transfer paper in which at least the curable resin layer and the print layer are sequentially formed on the base film layer. The curable resin layer is substantially cured in the process of transferring the gravure transfer paper to the steel plate coated with the primer so that the base film (also called a release film) layer is peeled off after the transfer process and the transfer coating film is not subjected to the continuous top clear coating process. This allows the layer to maintain good coating properties.

However, the gravure transfer paper of the present invention may further include structures such as a reinforcing layer and an adhesive layer in addition to the base film layer, the curable resin layer, and the printing layer.

Hereinafter, suitable primer paints and gravure transcripts to be applied to the present invention.

* Primer Paint *

As the base material (main resin) of the primer coating, it is preferable to use a flexible polyester resin having a molecular weight of 5,000 to 20,000 and a glass transition temperature (Tg) value of 10 to 50 ° C to maintain the flexibility of the transfer coating film.

In order to maximize the elongation, polyhydric alcohols such as ethylene glycol are used so that functional groups such as hydroxy group (-OH), carboxyl group (-COOH), etc., which are generally possessed in the main chain of the resin, have a linear structure. Therefore, it is necessary to suppress the formation of functional groups as much as possible to produce them.

The crosslinking resin (curing agent) used to form the coating film for the main resin (base material) of the primer paint is a mixed melamine resin of methylation and butylation. Commercially available RESIMINE 755, RESIMINE 757, RESIMINE 751 (from SOOLUTIA), CYMEL 1168, CYMEL 1170, CYMEL 232 (from CYTEL).

As the curing accelerator, sulfonic acids such as P-Toluene Sulfonic Acid and Dinonyl Naphthalene Solfonic Acid masked with epoxy resin are used.

Moreover, in order to improve adhesiveness, you may use auxiliary crosslinking resin of a primer paint. Here, isocyanates in the unyellowed form, such as masked hexamethylene diisocyanate, are used.

For primer paints, TiO ₂ white pigment is used in the case of internal type, and antirust pigment is added in case of external type to improve corrosion resistance. This may depend entirely on the demand of the price. That is, rust preventive pigments can be used without distinction between internal and external types.

The primer coating described above has a large elongation in addition to general corrosion resistance, strengthening adhesion between the transfer film and the plated steel sheet, surface smoothness, and the like, and thus possess a sufficient buffering effect at the interface between the base steel plate and the transfer coating film, resulting in processing. The crack does not develop to the transfer coating layer and serves to be absorbed in the undercoat layer.

It is preferable that a primer coating has the following composition ratios.

division ingredient Content (weight ratio) Suzy Polyester Resin 20-40 Melamine resin 4-15 Urethane resin 1 to 10 Auxiliary resin 0.3 to 3 Fee Titanium oxide (TiO2) 15 to 35 Antirust Pigment 0-10 additive DEFORMING AGENT 0.5 to 1.0 LEVELLING AGENT 0.5 to 1.0 UV FILLER 0.5 to 1.0 Solvent HYDROCARBON SYSTEM 15-25 ESTER system 15-25

* Gravure transfer paper *

Hereinafter, a layer structure of a gravure transfer paper is described.

Gravure transfer paper has five layers according to functions, namely biaxially oriented PET film layer, curable resin layer, printing layer, reinforcing layer, adhesive layer. These layered coating components can be prepared with some variations depending on the application applied. Hereinafter, these layers will be described in detail.

1) Base film layer (biaxially oriented PET film layer)

The base film layer is a layer located on the uppermost layer of the transfer paper, and a general biaxially oriented PET film having excellent heat resistance and tensile property is used. In some cases, the PET film may be embossed in advance to impart an embossed pattern to the product without undergoing a separate embossing process in the PCM line.

2) Curable Resin Layer

The curable resin layer is not only treated to provide a smooth peeling between the transfer coating film and the film, to prevent penetration into the color printing layer from the upper layer, to improve the printability of the color printing layer ink, and to provide post-processing and solvent resistance, as well as transfer process. It is substantially cured at, so that the transfer coating layer has good coating properties even if the topcoat clear is not coated after removing the release film (base film).

The curable resin layer uses i) polyester polyol or acrylic modified polyester polyol as main resin, and a mixture of hydroxyl-modified vinyl chloride copolymer and acrylic resin as auxiliary resin or ii) acrylic resin. (Acryl polyol) and a mixture of hydroxyl-modified vinyl chloride copolymer (Cell) and Cellulose Acetate Butyrate (CAB) system are used as an auxiliary resin. Hardener (isocyanate) is added in the field during printing to impart dense crosslinking to (i) or ii)).

In order to facilitate the removal of the release film, aromatic and ketone solvents are used for compatibility between non-silicon (PP, PE, fluorine, etc.) waxes and resins. And antifoaming agents as other additives.

The polyol used as the main resin uses a hydroxyl group of 50 ± 5, and the curing agent uses an unyellowed isocyanate having an NCO value of 20 ± 3 in masked hexamethylene diisocyanate.

Acrylic resin is a resin of MMA (methyl meta acrylate) series of 25,000 to 35,000 molecular weight, 17 to 20 hydroxyl value, 70 to 95 ℃ Tg value, vinyl resin is hydroxyl for bonding to the curing agent Modified vinyl chloride copolymer is used.

The CAB resin uses a resin having a molecular weight of 20,000 to 40,000, a Tg value of 120 to 160 and a melting point of 140 to 180 ° C in a CAB system (Cellulose Acetate Butyrate system).

3) calendar chain layer

The color printing layer to represent various colors and patterns

In order to show the color, special colored pigments for automobiles having heat resistance, UV resistance and solvent resistance are used, acrylic modified polyester is used as the main resin, and vinyl resin is used as the auxiliary resin. As the vinyl-based resin, VYHH, VYHD, and VYNS-3 (manufactured by UNION CARBIDE, USA), such as vinyl chloride-vinyl acetate copolymer having excellent heat resistance, may be used.

On the other hand, the basic pigment among the pigments used is a gelling property for the vinyl resin, so care should be taken, and it is necessary to selectively add a small amount of propylene oxide, n-butyl phosphate, diphenyl guanine, ammonia, etc. for storage stability. have. In addition, aromatic and ketone solvents and other additives are prepared by mixing a U.V filler for dispersing agent and ultraviolet ray reinforcement to prevent affinity and color separation of antifoaming agent, resin and pigment.

4) reinforcement floor

The reinforcement layer is formed between the printing layer and the adhesive layer for the concealment reinforcement of the base steel sheet and the color enhancement of the color printing layer, the same color reproduction, and thermal cutoff of the primer (primer).

The constituent of the reinforcing layer is a TiO ₂ white pigment based on an acrylic modified polyester resin used in the color printing layer, and the same solvents and other additives as the color printing layer are used.

5) Adhesive layer

The adhesive layer is formed to improve the adhesion between the transfer-oriented undercoat and the reinforcing layer finally painted on the surface of the base steel sheet, and selectively uses a polyester or polyurethane resin. In the case of polyester, it is preferable to use what has a molecular weight of 12,000-25,000 and Tg value of 40-65 degreeC. Adhesion is weak when the molecular weight is less than 12,000, and blocking is likely to occur when the molecular weight is 25,000 or more. In the case of polyurethane, it is preferable to use a resin having a molecular weight of 115,000 to 130,000, preferably a molecular weight of 30,000 to 100,000. If the molecular weight is less than 15,000, blocking is likely to occur, and if it is 130,000 or more, the adhesion decreases. In order to prevent blocking, it is preferable to use syloid (manufactured by GRACE DAVISON), which is a silica-based fumed FILED SILICA. In this case, in order to further strengthen the strength of the adhesive layer, a vinyl resin or CAB may be optionally used. Vinyl resin uses vinyl chloride-vinyl acetate-vinyl alcohol copolymer or vinyl chloride-vinyl acetate-marinic acid copolymer, VAGH, VMCH, VMCC, etc. among various compositions. The CAB system has a molecular weight of 55,000-60,000 and a butyl group having 50-55.

(Example)

Hereinafter, an example of manufacturing a gravure transfer printed steel sheet according to the present invention will be described.

Apply coated chromate on a sheet of steel plate with a coating layer of about 15-23㎛, using a thin film at a line speed of 20 ~ 80MPM in roll coating, and drying it with hot air at PMT (peak metal temperature) 60 ~ 140 ℃. A chromate layer of 20 to 80 mg / m 2 is formed. After roll coating a polyester primer having excellent elongation, corrosion resistance and adhesion to a dry coating thickness (DFT display) of 10-20 μm, and then heating the roll coated steel sheet in a dry oven at an ambient temperature of 160-280 degrees Celsius, It is dried to form a primer coating layer. The baking conditions should be changed according to the width and thickness of the base steel sheet and the line temperature, and the ambient temperature conditions to be baked should be 180 ~ 260 ℃ in the PCM continuous line.

It is preferable to roll coat the primer coating layer so as to have a dry coating thickness of 10-20 μm (DFT mark). The reason is that at 10 μm or less, the unevenness of the base remains as it is on the surface of the coating film, causing the occurrence of bubbles during transfer. Not only that, but also the lack of concealment results in inconsistent color reproducibility. At 20 micrometers or more of dry coat thickness, adhesiveness with a base material falls and economy is inferior. Preferably D..F.T is managed to be 14-15 탆.

And, the film thickness of 20-30㎛, the printed film thickness of 5-14㎛, transfer paper total on the surface of the undercoat coated steel sheet maintained at about 170-220 ℃ based on PMT (PEAK METAL TEMPERATURE, iron plate temperature) After attaching the gravure transfer paper having a thickness of 25-44 μm, using a heat-resisting elastic rubber roll with a roll surface temperature of about 40-60 ° C. cooled down, the transfer coating layer of the gravure transfer paper was transferred onto the primer-coated surface. After surface cooling treatment with water, the surface film (base film) of the transfer paper is separated and removed. Then, the gravure transfer coating layer is formed.

As for the thickness of the PET film layer of a transfer paper, 20 micrometers-30 micrometers are suitable. The reason is that the heat resistance and tensile resistance is less than 20㎛ less than the economical disadvantage is less than 30㎛.

And when a three-dimensional embossed pattern is required on the surface of the transfer film, using the embossed transfer PET film, a three-dimensional transfer coating film can be obtained immediately without a separate process of pressing down as an emboss roll in the process as before.

The thickness of the preferable transfer coating layer is 5 micrometers-14 micrometers. It is because release property and adhesiveness tend to be inferior in 5 micrometers or less, and workability and economy are inferior in 14 micrometers or more, Most preferably, 10 micrometers is suitable.

The colder the surface temperature of the roll, the easier it is to be transferred, but since it is difficult to manage below 40 ℃ because of the continuous work, it is managed to be below 60 ℃ as much as possible.

According to these conditions, the transfer steel sheet having the gravure transfer coating layer formed thereon is heated in a dry oven at an ambient temperature of 160-280 ° C. in a continuous working process to further enhance the transfer coating physical properties. Here, when the temperature of the dry oven is 300 ° C. or more (220 ° C. based on the PMT temperature), the transfer coating layer may be discolored. Preferably, the ambient temperature is 180-260 ° C. (180-200 ° C. based on PMT temperature).

Table 2 is a result of comparing the transfer steel sheet (see picture 1) and the conventional printed steel sheet (see picture 2) manufactured according to the above method and the reference figure is an example of the surface layer structure of the transfer steel sheet manufactured according to the present invention Display.

Product Classification Test Items Steel plate Printed steel sheet Tolerance Experimental condition Remarks 1. Peeling test ○ ○ Based on lowest value 50mm / min tensile load 2. Ericsson Exam ○ △ Do not peel off 5mm cross cut9mm ericsson 3. Flexural test ○ △ Hmm, broken, not peeled off 4 T break. (25 ± 5 ℃) 4. Content-based test 70 times 30 times Relative comparison M.E.K Rubbing 5. Chemical Resistance Test ○ ○ No corrosion or surface color change 10 NaOH solution, ethyl alcohol 6. UV resistance test ○ × No gloss and blister 20w × 20cm × 500hr 7. Weather resistance test ○ × No gloss and blister XENON ARC Lamp 300hr Count 8. scratch resistance 2H ^- H ^- Relative comparison Mitsubishi pencil endurance limit value Surface hardness 9. Corrosion resistance ○ △ No corrosion S.S.T 1000hr35 ?? 5aCl 9. Surface appearance 6 degrees 3 degree Maximum chromaticity Visual observation See picture

○: good / △: normal / ×: poor

(Reference)

Gravure Transfer Film Layer (5-14㎛) Primer coating layer (10-20㎛) Chromate Layer (20-80mg / ㎡) Plating insect (15-23㎛) Steel plate

(Photo 1)

(Photo 2)

According to the present invention as described above, compared to conventional printed steel sheet, the gravure transfer features other than general properties such as excellent post-processing, UV resistance, surface scratch resistance, solvent resistance, etc. It not only shows a beautiful exterior by expressing various patterns and colors, but also transfers only the embossed transfer film without the pressing process using a separate embossing roll to form a three-dimensional pattern on the surface. It is possible to manufacture non-clear gravure transfer printed steel sheet with a new sensitivity completely different from that of interior decoration, panel for interior decoration and exterior material, fire door, steel furniture, home appliance elevator, steel house assembly panel and general building material. It can be widely used for, for example.

Claims (7)

In the method of continuously manufacturing gravure transfer printed steel sheet in the PCM line, If a known base steel sheet or plating layer is formed, forming a chromate layer for rust prevention on the plating layer, Roll coating the primer paint on the chromate layer to heat and dry to form a primer coating layer, Transferring the gravure transfer paper on which the curable resin layer and the print layer were sequentially formed on the base film layer by heat and pressure on the primer coating layer; The curable resin layer is substantially cured when the gravure transfer paper is transferred onto the primer coating layer. A method of manufacturing a non-clear gravure transfer printed steel sheet, comprising: peeling the base film layer of the gravure transfer paper. The method of claim 1, The primer paint includes a flexible polyester having a molecular weight of 5,000 to 20,000 and a glass transition temperature of 10 to 50 ° C. as a main resin and a melamine resin as a crosslinking agent, The curable resin layer is iii) the main resin is a polyester polyol or an acrylic modified polyester polyol, the auxiliary resin is a mixture of a hydroxyl-modified vinyl chloride copolymer and an acrylic resin, and ii) the main resin is an acrylic polyol. Non-clear gravure, characterized in that the auxiliary resin comprises one selected from a mixture of hydroxyl-modified vinyl chloride copolymer (Cellulose Acetate Butyrate) and a curing agent (isocyanate) Method of manufacturing a transfer printed steel sheet. The method of claim 2, wherein the gravure transfer paper is a base film layer is a biaxially oriented crystalline PET film, and the non-free (non- clear) Manufacturing method of gravure transfer printed steel sheet. The method of claim 2, wherein the curable resin layer comprises a non-silicon wax. The method of claim 1, further comprising the step of peeling the base film layer of the gravure transfer paper to pass through the dry oven continuously to further strengthen the transfer coating layer non-clear gravure transfer. Method for producing printed steel sheet. The method of manufacturing a non-clear gravure transfer printed steel sheet according to claim 1, wherein the base film layer of the gravure transfer paper is embossed in advance. The method for producing a non-clear gravure transfer printed steel sheet according to any one of claims 1 to 6, wherein the thickness of each layer is in the following range. Base Film Layer: 20 ~ 30㎛ Dry coating layer of primer paint: 10-20㎛ Gravure Transfer Film Layer: 5-14㎛