WO2000040661A1

WO2000040661A1 - Printing composition, process and printing device using the same

Info

Publication number: WO2000040661A1
Application number: PCT/KR1999/000852
Authority: WO
Inventors: Chul-Hyun Uhm; Chuk-Yeon Mo
Original assignee: PRIME CHEMICAL CO Ltd
Current assignee: PRIME CHEMICAL CO Ltd
Priority date: 1998-12-31
Filing date: 1999-12-31
Publication date: 2000-07-13
Anticipated expiration: 2001-06-30
Also published as: AU1896300A; KR20000047031A; KR100287257B1

Abstract

The present invention relates to a process and a device for printing which can transfer a printed pattern formed on a negative plate to a printing medium simply by contacting the negative plate with the printing medium without any mediating means such as heat or water, just under the condition where a printing composition for printing is interposed. The printing composition includes (a) resin selected from the group consisting of a homopolymer or copolymer of vinyl chloride (PVC), a homopolymer or copolymer of ethyl terephthalate (PET), a homopolymer or copolymer of acrylate (AC), a homopolymer or copolymer of carbonate (CA), and mixture thereof; (b) plasticizer; and (c) organic solvent. The printing process comprises the steps of (a) preparing a negative plate on which a predetermined printed pattern has been realized; (b) forming a printing layer by coating the surface of the negative plate with a printing composition of claim 1; and (c) covering a printing medium on the top of the printing layer and pressing the printing medium.

Description

PRINTING COMPOSITION, PROCESS AND PRINTING DEVICE USING THE SAME

This application claims benefit of Korean Patent Application No. 98-63780, filed on December 31, 1998, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to a novel printing composition, process and device for printing which uses the printing or transcription composition. More specifically, the present invention relates to a process and device for printing which can transfer a printed pattern of a negative plate to a printing medium simply by contacting the negative plate with transcription medium without any mediating means such as heat or water.

Background Art

Generally, printing is divided into hard printing and special printing, depending on the type of transcription medium through which the transcription is performed. Hard printing uses paper as the transcription medium, while special printing uses various materials other than paper as the transcription medium. Representative techniques of special printing include silk screen, computer printing and decal printing.

Silk screen is a printing process which prepares a substrate on a screen having meshes and then prints the subject to be printed by squeezing ink through the meshes of the screen by means of a squeezer or rubber roller. The printing medium may be nylon, teflon, metal, silk or other screen materials known to one of ordinary skill in the art.

Printing by silk screen has advantages in that (1) it is cheap because its equipment is simple and the plate-making is simple; (2) it is suitable for printing in small quantities; (3) various kinds of material may be used as the subject to be printed; (4) printing on a curved surface is made possible because the flexibility of the plate is good; and (5) prints of intensive color can be obtained because of a large quantity of ink coloration.

On the contrary, the silk screen process has disadvantages in that (1) a quantity more than a certain amount of works should be secured; (2) color expression is restricted; (3) the degree of distinction is low; (4) loss of color and pin is high; and (5) maintenance or repair of the finished product is difficult.

A computer printing generally comprises editing the subject to be printed by the use of a computer and offering an output by means of a printer, or the like. It has advantages in that (1) computer editing affords various designs and color expressions; and (2) the degree of distinction is excellent. However, it has disadvantages in that (1) manufacturing in a large quantity is difficult because of low productivity; (2) production cost is expensive; and (3) printable materials are limited (usually, overhead projector film, print paper or a coating paper), so that the applicable field is also restricted. Thus, in a case of preparing signboards by use of an acrylate board or PVC board, computer printing is not desirable. In order to prepare signboards, a wide color mode or a chroma color mode is employed, but these printing modes have many problems such as production cost, durability, resolution, or the like.

Decal printing comprises engraving a printed pattern on a decal paper and transcribing the pattern to a printing medium. Decal paper; a single paper, such as chrom paper or china paper; composite paper having two layers; and separate paper, which is prepared by laminating high-quality vellum paper and coating polyvinyl resin thereon to finish off, can be used. The composite paper is prepared by attaching a rice paper (thin paper) on a large paper, drying the paper, applying a special coating (a mixture of iron powder, arabia gum and sodium malkinate) thereon and then polishing the coating . The transcription process comprises the steps of printing a pattern on the decal paper by the use of direct lithography, dispersing pigments (colors for ceramic ware) immediately before drying ink, and coating with lacquer. Meanwhile, the pigment is transcribed if a fast-drying lacquer is coated on the ceramic ware. Before drying, a rice paper is attached and water is applied thereon; then the rice paper is taken off. The ceramic ware is baked (heat transcription) in a calcine furnace at an appropriate temperature, then the pigment is fused and attached. Such decal printing is employed in the transcription of various containers besides ceramic wares. Printing is made with ink, and the transcribed pattern is protected by spraying transparent lacquer after completing the transcription. A heat transcription mode as described above is employed for the production of stationeries, utensil goods, toys and souvenirs, and suitable for mass production at low cost. However, this is disadvantageous in that the applicable range is restricted, because printing a complicated and precise pattern, such as advertising goods or copy of a masterpiece, is impossible.

In the meanwhile, Japanese Patent Publication No. Sho 52- 41682 discloses a water transcription mode that uses water as a medium. According to the invention, a pattern is printed on a decal paper by using colors or printing ink, the decal paper is floated on a liquid phase, and a transcription medium is compressed to the surface of the decal paper to transfer the printed pattern to the transcription medium due to the liquid pressure. However, in this mode, the decal paper should have excellent flexibility and softening properties, as well as good swelling and developing properties, as an oblate, because the decal paper must be removed from the surface of the transcription medium. However, in case a special decal paper is floated on the surface of the water, the pattern printed on the surface is prominently diffused and deformed prior to transcription; thus, it is disadvantageous in that the desired pattern cannot be obtained. In order to solve this problem, Japanese Patent Publication No. Sho 57-50547 and U.S. Patent No. 4,010,059 disclose a_. technique in which the film is substituted with a water-soluble film. That is, a predetermined pattern is printed on the surface of a water-soluble base (the subject to be transcribed) , an adhesive is coated thereon, and the base is floated on water. Then the water-soluble base is dissolved in water, and the printed pattern floats on the surface of water in a semi-flowable state. At this time, the transcription medium is compressed on the top of the printed pattern in a semi-flowable state to perform transcription.

According to the printing process described above, it is possible to transcribe a pattern to a curved surface or an uneven surface, and the process is suitable for using subjects such as plastic clock cases or TV housings as the transcription medium.

However, the water transcription mode as mentioned above is disadvantageous in that printing of only one color is possible in a single printing process. As soon as the transcription medium contacts the pattern floating on the liquid, the transcription is carried out; thus, the ink that constitutes the printed pattern must be in a dry state. Accordingly, printing with another color ink is impossible until the printing ink of the prior step is completely dried. Consequently, in order to form a multi-color-printed pattern, printing with another color cannot be carried out until the print ink of the prior step is dried. In addition, the rate of the printer, which forms the pattern to be transcribed on the medium to be transcribed, should be adjusted so that the medium is supplied at such a rate corresponding to the transcription rate carried out in the liquid tank. However, as the printing rate of a printer is usually faster than a transcription rate in the liquid tank, the printing rate is intermittently adjusted according to the transcription rate. This, however, is very difficult. Further, there are problems in that the printed pattern cannot be completely attached to the transcription medium and separated from the medium, or that the figure of the pattern is decolorated or discolorated to deteriorate the color tone.

Besides, according to the water transcription mode as above, it is impossible to print a figure of beauty and rich color sense on a film like an oblate; thus, just simple printed patterns can be obtained. In particular, in the case of using a water-insoluble film as a medium to be transcribed, it is difficult for a print pattern to be transcribed on a delicate uneven surface, owing to the existence of the film. Thus, transcription to a transcription medium having a complicatedly curved surface is substantially impossible. Further, since the water- insoluble film must be removed from the transcription medium by physical or chemical means after the transcription is completed, the printed pattern is apt to be damaged and the printing process becomes complicated.

DISCLOSURE OF THE INVENTION

The present invention solves the problems of a conventional printing mode, and it does not require a primary printing stage (or pattern-forming stage) of the printed pattern on the medium to be transcribed. The present invention provides a novel printing solution that allows the printed pattern on the negative plate to be directly transcribed to the printing medium or binds the negative plate and the printing medium.

Further object of the invention is to provide a printing process that can increase the scope of usable negative plates and transcription media by using the printing solution.

Another object of the present invention is to provide a printing process having a simple printing process and low process cost, by using the printing solution.

Still another object of the present invention is to provide a printing process that gives excellent image reappearance without pattern damages, owing to heat or the like, and has high gloss and excellent diffused reflection. In addition, another object of the invention is to provide various printed goods that are prepared by the printing process.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof, as well as the appended drawings .

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a printing composition comprises resin; plasticizer; and organic solvent. The mixed ratio of the resin : the plasticizer : the organic solvent is about 1 : 0.01-0.5 : 1-15, and preferably about 1 : 0.005-0.2 : 2-10. The resin may be a homopolymer or copolymer of vinyl chloride, ethyl terephthalate, acrylate (AC) , carbonate and derivatives thereof, such as polyvinyl chloride (PVC) , poly ethyl terephthalate (PET) and so on.

According to one aspect of the present invention, the homopolymer or copolymer of vinyl chloride may be homopolymer of vinyl chloride (PVC-S) or a copolymer of vinyl chloride and vinyl acetate (PVC-M) . The AC may be methyl acrylate; ethyl acrylate; acrylonitrile; methyl methacrylate; or acrylic ester.

It is more preferable that the resin is mixture of poly (vinyl chloride / vinyl acetate) and poly (methylmethacrylate) and most preferably, the resin is 443 resin manufactured by Union Carbite Ltd.

In addition, the plasticizer may be dibutyl phthalate (DBP), dioctyl phthalate (DOP), dimethyl phthalate (DMP) , diethyl phthalate (DEP), dioctyladipate (DOTP) , tricresyl phosphate (TCP) and triphenyl phosphate (TPP) , and more preferably, the plasticizer is dioctyl phthalate (DOP) ,

According to another aspect of the present invention, the organic solvent may be cyclohexanone, methyl 3- methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, 2-methoxyethyl acetate, 2- heptanone, isobutyl methyl ketone, toluene, benzene, tetrahydrofurane, dimethyl formamide (DMF) , dimethyl sulfoxide, dioxane, methyl ethyl ketone, xylene and nitrobenzene, and more preferably, the organic solvent is a mixture of toluene, cyclohexanon and DMF.

To prepare the printing composition, the resin of about 3 to 4 kg is mixed with toluene of about 3-4 kg, cyclohexanon of about 2-2.5 kg, DMF of about 2-2.5 kg and DOP of about 200-250 g. Particularly, the printing composition is prepared by mixing the resin of about 3.45 kg with toluene of about 3.6 kg and stirred at about 120 rpm for about 5 minutes to form a first composite solution; idling the first composite solution for about 10 minutes then adding cyclohexanon of about 2.14 kg to the first composite solution and stirring at about 240 rpm for about 5 minutes to form a second composite solution; idling the second composite solution for about 10 minutes then adding DMF of about 2.35 kg to the second composite solution and stirring at about 120 rpm for about 10 minutes to form a third composite solution; idling the third composite solution for about 20 minutes then adding DOP of 225 g to the third composite solution and stirring at about 12 rpm for about 2 minutes .

According to one embodiment of the present invention, a printing process comprises the steps of (a) preparing a negative plate on which a predetermined printed pattern has been realized; (b) forming a transcribed layer or bonding layer by coating the surface of the negative plate with a printing composition comprising resin, plasticizer and organic solvent; and (c) covering a printing medium on the top of the transcribed layer or bonding layer and pressing the printing medium. The mixed ratio of the resin : the plasticizer : the organic solvent is about 1 : 0.01-0.5 : 1- 15. In this embodiment, a step of forming a pretreatment layer on the negative plate may be performed prior to step (b) . The step (b) of forming the transcribed layer or bonding layer is performed by at least one of spraying the printing composition on the negative layer, applying the composition on the negative plate and dipping the plate into the printing composition.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention .

In the drawings:

Figs, la to Id are cross-sectional views for illustrating the printing process according to Example 1 of the present invention;

Figs. 2a and 2b are cross-sectional views which illustrate a printing process according to the present invention; Figs. 3a and 3b are cross-sectional views which illustrate an other printing process according to the present invention;

Fig. 4 is a schematic diagram which illustrates the printing device according to the present invention; Figs. 5a and 5b illustrate an offset output pattern and a transcribed pattern according to the present invention, respectively, corresponding to the same pattern;

Figs. 6a and 6b are a magnified view and cross-sectional view, respectively, of dots of the pattern shown in Fig. 5a; Figs. 7a and 7b are a magnified view and cross-sectional view, respectively, of dots of the pattern shown in Fig. 5b; and Figs. 8a and 8b illustrate resultant patterns obtained by printing an identical pattern via silk screen and the process according to the present invention, respectively.

Figs . 9a and 9b illustrate resultant patterns obtained by printing an identical pattern via photograph and the process according to the present invention, respectively.

Figs. 10a and 10b illustrate resultant patterns obtained by printing an identical pattern via ink-jet printing mode and the process according to the present invention, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to overcome the problems of conventional techniques, the preferred embodiments of the present invention use a process for performing the transcription by directly placing a printing medium on a negative plate and then transferring the pattern from the negative plate to the printing medium through a printing layer formed between the negative plate and the printing medium. The transfer of the pattern as above is caused by a special chemical reaction of the printing layer and pattern on the negative plate. Thus, the present invention realizes transcription of a pattern to another medium by simple contact of the negative plate with a printing medium using a printing solution.

In addition, the printing solution according to the present invention functions as a simple bonder according to the natural gifts of the negative plate. That is, when the negative plate is an art paper on which a chemical treatment is performed, transcription is occurred through the printing layer formed by coating the printing solution. However, when the negative plate is a photograph, a plain paper, woven goods and so on, the printing solution functions as a binder rather than a transcription solution.

The printing solution according to the present invention i_{s a} mixture comprising (1) one or more resin (s) selected from the group consisting of a homopolymer or copolymer of vinyl chloride (PVC, referred hereinafter); a homopolymer or copolymer of ethyl terephthalate ( PET, referred hereinafter); a homopolymer or copolymer of acrylate (AC, referred hereinafter); a homopolymer or copolymer of carbonate (CA, referred hereinafter); and mixture thereof; (2) a plasticizer; and (3) an organic solvent.

As the resin, PVC includes homopolymer of vinyl chloride (PVC-S) and copolymers of vinyl chloride and vinyl acetate (PVC-M) , in particular, preferred is Resin 443 manufactured by Union Carbide of Taft, Louisiana. AC includes homopolymers and copolymers of methyl acrylate, ethyl acrylate, acrylonitrile, methyl methacrylate and/or acrylic ester. At this time, the copolymers of vinyl chloride and vinyl acetate (PVC-M) is more preferred and Resin 443 is most perferred.

The plasticizer is used for dissolving the resin and includes dibutyl phthalate (DBP) , dioctyl phthalate (DOP) , diisooctyl phthalate, dimethyl phthalate (DMP), diethyl phthalate (DEP) , dioctyladipate (DOTP) , tricresyl phosphate (TCP), triphenyl phosphate (TPP) and so on. In addition, conventional plasticizers may be used. The organic solvent dilutes the resin solution in a proper concentration, so as to facilitate applying the solution on the negative plate and forming the pretreating layer in an even thickness. Thus, any organic solvent may be used, as far as it satisfies the function as a solvent, but preferably a solvent may be selected depending upon the properties of the resin used. As the case may be, a mixed solvent of two or more solvents is preferable.

Usable organic solvents include cyclohexanone, methyl 3- methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, 2-methoxyethyl acetate, 2- heptanone, isobutyl methyl ketone, toluene, benzene, tetrahydrofurane, dimethyl formamide (DMF), dimethyl sulfoxide, dioxane, methyl ethyl ketone, xylene and nitrobenzene. The mixed ratio of resin : plasticizer : organic solvent preferably is about 1 : 0.005-0.5 : 1-15 in the weight ratio (weight (kg) of the resin being 1), and more preferably about 1: 0.005-0.1 : 1.5-10. In order to remove the odor of organic materials, deodorant or perfume may be additionally incorporated. As a deodorant, conventional deodorants, such as sodium hypochlorite, known to one of ordinary skill in the art, may be used.

As the means for applying the printing solution on the negative plate, any means which can form an even transcribed layer can be used, for example, the printing solution can be applied by spraying on the negative layer by means of nozzle, by applying on the negative plate by means of a brush and then squeezing, or by dipping the plate into the printing solution .

The printing process according to the present invention varies, depending upon the type of printing ink which consists of the printed pattern, and the type and thickness of the printing medium, but generally it consists of three stages of preparing the negative plate, pretreatment and transcription or binding by press.

Figs, la to Id illustrate the printing process according to an embodiment of the present invention and cross- sectional views of the transcription process using a negative plate, having a printed pattern comprised of toner or aqueous dye .

First, a negative plate (10) is prepared as illustrated in Fig. la.

As the negative plate (10) in the present invention, a conventional paper, an art paper on which a certain chemical treatment is done, photograph, texture, resin film and so on can be used. Especially, when a substance on which a certain chemical treatment is done, such as the art paper, as the negative plate, the printing procedure according to the present invention is carried out in the way of transcription. On the other hand, when a substance on which no certain chemical treatment is done, as the negative plate, the printing procedure according to the present invention is generally carried out in the way of binding rather than transcription. Next, on the surface of the negative plate, a printed pattern (10) has been formed. According to the present invention, various material can be used as the negative plate (10) such as a conventional printing output, gravures, photographs, ink-jet printings, and so on. In other words, the negative plate itself can be used as the medium to be transcribed, without individually realizing the printed pattern of the negative plate on a certain decal paper, being different from conventional decal printing. Thus there is no problem involved with restricting the decal paper to an oblate or a water-soluble film such as limited color expression, the inferior color tone, or being able to transcribe only one color via one transcription process and a complicated process. Especially, art paper on which a certain chemical treatment was performed is very useful as a negative plate for transcription. In addition, conventional photographs or pictures itself is generally used as the negative plate for binding.

Meanwhile, before performing the transcription process, it is desirable to carry out a pretreating process in order to stabilize the surface condition of the negative plate. In other words, the pretreating process is performed so as to prevent diffusion or secession of printing ink, which constitutes the printed pattern (20), during the transcription process.

In particular, aqueous ink or toner, being different from oily ink or pigment, has weak adhesive power to the negative plate, and dots are dispersed over a relatively wider area, thereby having disadvantages in that the surface condition is unstable. Thus, in a case where the printed pattern of such condition is transcribed as it is, the printed pattern is diffused or deformed during the transcription process to deteriorated degrees of distinction of the pattern transcribed to the transcription medium.

Thus, as illustrated in Fig. lb, occurrence of stains or bubbles can be prevented by forming a pretreatment layer (30) through applying the pretreating solution on the surface of the printed pattern to fill up the voids between each dot. This prevents printing ink getting loose on the negative plate and avoids occurrence of stains or bubbles during the transcription process. However, as pigments or oily ink have superior adhesive power to the negative plate and stability to aqueous ink, the pretreating process may be omitted .

Because the necessity of coating the pretreating layer (30) and the thickness of coating vary, depending upon the type of the printing ink and type of the negative plate, it is desirable to detect the surface condition of the negative plate prior to the pretreatment process, and to carry out the process according to the resultant data. As the device for detecting the surface condition of the negative plate (10), a microscope, or the like, may be used. The thickness of the pretreating layer (30) preferably is about 20 micrometers to 30 micrometers. The pretreating solution is a mixed solution comprising one or more resins selected from a group consisting of a homopolymer or copolymer of vinyl chloride (PVC) ; a homopolymer or copolymer of ethyl terephthalate (PET) ; a homopolymer or copolymer of acrylate (AC) ; a homopolymer or copolymer of carbonate (CA) ; and mixture thereof; and (2) an organic solvent.

The resin and organic solvent are as same as used to prepare the printing solution. That is, the resin includes a homopolymer or copolymer of vinyl chloride (PVC) ; a homopolymer or copolymer of ethyl terephthalate (PET) ; a homopolymer or copolymer of acrylate (AC) ; a homopolymer or copolymer of carbonate (CA) ; and mixture thereof; and the organic solvent includes cyclohexanone, methyl 3- methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, 2-methoxyethyl acetate, 2- heptanone, isobutyl methyl ketone, toluene, benzene, tetrahydrofurane, dimethyl formamide (DMF) , dimethyl sulfoxide, dioxane, methyl ethyl ketone, xylene and nitrobenzene . The mixed ratio of resin : organic solvent preferably is about 1 : 1-15 (weight (kg) of the resin being 1), and more preferably is about 1: 1.5-10. As the means for applying the pretreating solution on the negative plate, any means which can form an even pretreating layer (30) can be also used, for example, the pretreating solution can be applied by spraying on the negative layer by means of nozzle, by first applying on the negative plate by means of a brush and then squeezing, or by dipping the plate into the pretreating solution.

After the pretreatment, the negative plate is dried for a certain time period, and then subjected to the printing process for transcription or bonding. The drying condition varies, depending upon type and size of the transcription medium, but drying is generally performed at about 80-100 Celsius degrees for about 30 minutes to 2 hours.

The printing process is generally performed by forming a printing layer (40) by applying the printing solution on the negative plate (10), and pressing the printing medium (50) on the top of the printing layer, as illustrated in Fig. Id. According to the simplest process, the printing layer is formed by handwork, for example, by the use of brush or the like, and the printing medium is laid on top of the layer, and the upper surface is evenly pressed by hands. The process can be performed by a printing device (100) as illustrated in Fig. 4.

Referring to Fig. 4, the printing device (100) includes a pressing cylinder (160), a plate cylinder (170), a negative plate supplier (130), a printing medium supplier (140), and a printing solution supplier (150) . First, the negative plate (10) in which the pretreatment process has been completed is supplied from the negative plate supplier (130). Then the printing solution is supplied to the surface of the negative plate from the printing solution supplier (150), for example, a nozzle, to form a printing layer (40) . The thickness of the printing layer (40) may be adjusted depending on the thickness and texture of the negative plate (10) and the printing medium (50), but generally is 20 μm to 30 μm. Then the negative plate (10) is transferred to the pressing cylinder (160) . Meanwhile, the printing medium supplier (140) supplies transparent or translucent printing medium (50) to the plate cylinder (170). Then, by revolving the pressing cylinder (160) and plate cylinder (170), the negative plate (10) and the printing medium (50) are withdrawn in a pressed condition with the printing layer (40) between them.

The fluid pressure applied to the negative plate (10) and printing medium (50) through the pressing cylinder (160) and the plate cylinder (170) and the extruding rate vary, depending upon the thickness and size of the printing medium as exampled in following Table 1. But, in general, it is desirably extruded under the fluid pressure of about 2 to 10 kg and the rate of about 50 to 300 rpm. The thickness of the printing medium is not restricted, but preferably is about 0.1 mm to 10 mm depending on the type of image being printed or transferred.

Table 1

T is shown in unit of mm/mm.

A4 means size of 21 x 29.7 (cm x cm), A2 means size of 42 x 59.4 (cm x cm), Al means size of 59.4 x 84.1 (cm x cm), and A0 means size of 84.1 x 117.4 (cm x cm) .

As described above, especially when the negative plate (10) is a so-called art paper on which a chemical treatment was done, the printed pattern (20) on the negative plate (10) is transferred to the printing medium (50) via the printing layer (40) simply by predetermined pressure, and, as a result, the negative plate remains as a white paper. Thus the problems of conventional transcription processes using heat or water as the medium are completely solved.

Then the negative plate (10) may be removed as required, or it is used in the attached state. Or it may be used in a sandwich-like form, where the negative plate (10) is inserted between the printing media (50) by attaching another printing medium on the back of the printing medium (50) to which the negative plated is attached. In a case of removing the negative plate (10), an individual treatment (for example, by painting white color or the like) is desirably performed on the back surface.

In the case of using a negative plate on which a separate chemical treatment is not done, the printing solution according to the present invention generally functions as binder. Thus, the negative plate (10) is not removed and remains in the attached state.

Though the stage of supplying the printing solution on the negative plate (10) and that of compressing the printing medium (50) on the top thereof are individually proceeded in the above example, these stages may be simultaneously carried out. In other words, if the printing solution is supplied at the same time of applying one end of the negative plate by a pressing cylinder (160), the printing process can be performed in such a way that the printing medium (50) squeezes and compresses the printing solution.

As the printing medium in the present invention, all transparent or translucent resin having various thickness and size; a texture or paper whose surface is subject to chemical treatment; and so on may be used. This is quite different from conventional printing techniques. That is, it was difficult for the conventional printing technique to directly print a predetermined pattern on a resin. Furthermore, conventional printing technique has a restriction in size and thickness of printing media.

The printing media can be largerly divided, depending its hardness, into hard resin and soft resin.

First, the hard resin include such as AC, hard PVC, polyethylene terephthalate glycol (PETG) , polyethylene terephthalate (PET) , polyethylene terephthalate-glycol- amorphous glycol (PET-GAG), polycarbonate (PC) , and so on. The resultant goods obtained by employing such hard resin include various panels, posters, sign boards for display or commercial use, POP (point of purchase) advertisements, interior goods, military supplies, panels for vending machines, game machines, office supplies, various safety goods such as helmets, electric home appliances, and the like. on the other hand, the soft resin include soft PVC, Panaflex, polycarbonate (PC), polyurethane (PU) and various R&D media, and the resultant goods obtained thereby includes commercial goods involving portrait right, which use famous characters from various sports, entertainers, animated cartoons or game machines, various sign boards for display or commercial use, utensil goods such as table mats, various trays and fashion tiles, sporting goods such as soccer balls, baseballs, basketballs and footballs, copies or mounted pictures of a drawing work including masterpieces of famous painters, religious pictures, oil paintings and oriental paintings, various maps or wall charts for military, traffic, industrial or educational use, various stickers or emblems used for shoes, hats, bags or clothing accessories, designed bags or caps for various sports or leisure time, stationery goods such as system diaries, albums, files, binders, white boards, rulers and pencil cases, various small pieces such as mouse pads for computers and post cards, and covers of books or dictionaries.

The printed products may be also divided into lighting products such as sign board and non-lighting products such as photographs, book covers, copies of masterpieces or mountings, depending upon the usable field of the resultant products; and divided, depending upon the thickness of the printing medium, into "board" products having the thickness of 1 mm or more and so-called "sheet" products having the thickness of 1 mm or less.

Figs. 2a and 2b illustrate a printing process according to the present invention which includes a pretreating process. Fig. 2a illustrates the condition where the printed pattern (20a) is made on the negative plate (10a) by means of lithography. Fig. 2b shows the condition where the pretreating solution is put into the dots of the printed pattern (20a) .

The printed pattern (20a) on the negative plate (10a) obtained by lithography is very flexible and soft. However, it has disadvantages in that the intensity of printing is insufficient and printing durability is weak because the printing pressure is weak and the degree of transfer is low. Thus, a transcribed pattern of uniform quality can be obtained by forming a pretreating layer (30a) on the whole surface of the printed pattern (20a) to enhance the printing durability of printing ink. Other procedures are identical to those in Figs. la-Id.

Figs. 3a and 3b are drawings illustrating an other printing process according to the present invention. Fig. 3a illustrates the condition where the printed pattern (20b) is made on the negative plate (10b) by means of engrave printing technique. Fig. 3b shows the condition where the pretreating layer (30b) is not formed on the surface of the printed pattern (20b) .

In the printed pattern (20b) on the negative plate (10b) obtained by engrave printing, ink is transferred to the subject to be printed, after adhering ink on the concave section, because the part of the drawing line has a lower surface than the part having no printed pattern. According to this technique, thick ink film is formed and the adhesion of ink is relatively stable, so that the printing process of the present invention can be proceeded without a pretreating process. However, in a case of employing pretreating process, a soft transcribed pattern having milder color tone is obtained. Thus, the decision whether the pretreating process should be performed or not can be made depending on the properties of the desirable pattern to be transcribed. Other procedures are identical to those of those in Figs. la-Id.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the present invention is described in more detail by referring to the Examples. However, it should not be understood that the present invention is restricted to these Examples by any means.

Example 1 (1) Preparation of pretreating solution

First, 443 resin weighing about 3-4 kg, preferably about 3. 45 kg, manufactured by Union Carbide is poured into toluene solvent weighing about 3-4 kg, preferably about 3.6 kg. The resultant solution is stirred at a speed of about 120 rpm for about 5 minutes. After about 10 minutes, cyclohexanon weighing about 2-2.5 kg, preferably about 2.14 kg, is added and stirred at a speed of about 240 rpm for about 5 minutes. After the resultant solution is laid for about 10 minutes, DMF weighing about 2-2.5 kg, preferably about 2.35 kg, is added and stirred at a speed of about 120 rpm for about 10 minutes, and thus, forming the pretreating solution. (2) Preparation of printing solution First, 443 resin weighing about 3-4 kg, preferably about

3. 45 kg, manufactured by Union Carbide is poured into toluene solvent weighing about 3-4 kg, preferably about 3. 6 kg. The resultant solution is stirred at a speed of about 120 rpm for about 5 minutes. After about 10 minutes, cyclohexanon weighing about 2-2.5 kg, preferably about 2.14 kg, is added and stirred at a speed of about 240 rpm for about 5 minutes .

After the resultant solution is laid for 10 minutes, DMF weighing about 2-2.5 kg, preferably about 2.35 kg, is added and stirred at a speed of about 120 rpm for about 10 minutes. After about 20 minutes, DOP weighing about 200-250 g, preferably about 225 g, is added thereto and stirred at a speed of about 120 rpm for about 2 minutes and thus, forming the printing solution.

(3) Prosecution of printing process

First, an art paper of A0 size was prepared as a negative plate (10) on which a predetermined pattern is formed by off-set printing, as illustrated in Fig. 5a. Then, the pretreating solution, which had been prepared in advance, is applied over the whole surface of said negative plate (10) to form a pretreatment layer (30) having thickness of about 30 micrometer, which is dried at about 80 degrees Celsius for about 30 minutes. (See Fig. lb.)

Then, a printing layer (40) having thickness of about 30 μm was formed on the surface of said pretreated layer (30), by means of the device for printing printing (100) according to the present invention. Thereafter, a PC plate having over A0 size (thickness of about 3 mm) is covered on the top of said transcribed layer (40), and fluid pressure of about 7 kg is applied thereon to compress them to obtain a transcribed pattern illustrated in Fig. 5b.

As can be seen from Figs. 5a and 5b, degree of distinction of the printing pattern obtained by the printing process of the present invention (Fig. 5b) is superior to the negative plate (10) obtained by offset printing. The dot properties when the negative plate (Fig. 5a) and the printing pattern (Fig. 5b) were observed through microscope are illustrated by Figs. 6a and 7a, respectively. As can be seen from Figs. 6a and 7a, the printed pattern (Fig. 7a), though it was seized in a low magnification, has clearer viewpoint than the pattern on the negative plate (6a) which was seized in a high magnification. This fact is confirmed again from Figs. 7a and 7b which illustrate the cross-sectional dot of the pattern before and after print, respectively. In other word, the pattern after printing process (illustrated by Fig. 7b) has smaller surface area occupied by each dot as compared to the printed pattern before printing process. In addition, vertical distribution of dots shows steep inclination (increase of sharpness) . Thus, according to the printing process of the present invention, dot properties of a printed pattern is enhanced, and a printed pattern having improved degree of distinction and resolution can be obtained.

Example 2

A pretreating solution and printing solution were prepared according to the same procedure of Example 1, and the negative plate was the same art paper as Example 1.

Using the same negative plate, silk screen process and printing process according to the present invention were performed, and the results were shown in Figs. 8a and 8b, respectively.

The printing process according to the present invention is carried out according to the same procedure of Example 1, but using employing an acrylate plate as the printing media of 5mm thickness.

As shown in Figs. 8a and 8b, the print pattern (Fig.8b) obtained from the printing process according to the present invention is clearer than that of silk screen (Fig. 8a) .

Example 3

A pretreating solution and printing solution were prepared according to the same procedure of Example 1, and the negative plate was a photograph. Using the same negative plate, wild color process and printing process according to the present invention were performed, and the results were shown in Figs. 9a and 9b, respectively .

The printing process according to the present invention is carried out according to the same procedure of Example 1, but using employing an polycarbonate plate of 2mm thickness as a printing media of 5mm thickness.

INDUSTRIAL APPLICABILITY

As described above, the present invention has advantages as following:

(1) it is possible to use a resin as a printing media;

(2) a pattern having good resolution can be obtained by simple process, (3) process cost is lower, (4) various nature of negative plate can be used which is hardly used under a conventional art, and so on.

Claims

WHAT IS CLAIMED IS:

1. A printing composition comprising:

(a) resin selected from the group consisting of a homopolymer or copolymer of vinyl chloride (PVC) , a homopolymer or copolymer of ethyl terephthalate (PET) , a homopolymer or copolymer of acrylate (AC) , a homopolymer or copolymer of carbonate (CA) , and mixture thereof;

(b) plasticizer; and

(c) organic solvent.

2. A printing composition according to claim 1, wherein said rein is poly (vinyl chloride); poly (vinyl chloride / vinyl acetate) ; a homopolymer or copolymer of ethyl acrylate; a homopolymer of acrylonitrile; or a homopolymer of methyl methacrylate.

3. A printing composition according to claim 1, wherein said rein is a Resin 443 manufactured by Union

Carbide of Taft, Louisiana.

4. A printing composition according to claim 1, wherein said plasticizer is selected from the group consisting of dibutyl phthalate (DBP) , dioctyl phthalate (DOP) , diisooctyl phthalate, dimethyl phthalate (DMP) , diethyl phthalate (DEP), dioctyladipate (DOTP), tricresyl phosphate (TCP) , and triphenyl phosphate (TPP) .

5. A printing composition according to claim 1, wherein said organic solvent is selected from the group consisting of cyclohexanone, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, 2-methoxyethyl acetate, 2-heptanone, isobutyl methyl ketone, toluene, benzene, tetrahydrofurane, dimethyl formamide (DMF), dimethyl sulfoxide, dioxane, methyl ethyl ketone, xylene and nitrobenzene.

6. A printing composition according to claim 1, wherein the ratio of resin : plasticizer : organic solvent is 1 : 0.005-0.5 : 1-15.

7. A printing composition according to claim 6, wherein the ratio of resin : plasticizer : organic solvent is 1: 0.005-0.1 : 1.5-10.

8. A printing composition according to claim 1, wherein said negative plate is selected from the group consisting of a conventional paper, an art paper, photograph, texture and resin film.

9. A printing composition according to claim 1, wherein said printing medium is a resin.

10. A printing composition according to claim 1, wherein

(a) said resin is poly (vinyl chloride / vinyl acetate),

(b) said plasticizer is dioctyl phthalate (DOP) or diisooctyl phthalate, and

(c) said organic solvent is a mixture of cyclohexanone, toluene, and dimethyl formamide (DMF) .

11. A printing composition according to claim 10, wherein said resin further comprising poly (methyl methacrylate) .

12. A printing composition according to claim 10, wherein said resin is Resin 443 manufactured by Union Carbide of Taft, Louisiana.

13. A pretreating solution comprising:

(a) a resin selected from the group consisting of a homopolymer or copolymer of vinyl chloride (PVC) , a homopolymer or copolymer of ethyl terephthalate (PET) , a homopolymer or copolymer of acrylate (AC) , a homopolymer or copolymer of carbonate (CA) , and mixture thereof; and (b) an organic solvent.

1 . A pretreating solution composition according to claim 13, wherein said rein is poly(vinyl chloride); poly (vinyl chloride / vinyl acetate); a homopolymer or copolymer of ethyl acrylate; a homopolymer of acrylonitrile; or a homopolymer of methyl methacrylate.

15. A pretreating solution according to claim 13, wherein said rein is a mixture of poly (vinyl chloride / vinyl acetate) and poly (methyl methacrylate) .

16. A pretreating solution according to claim 13, wherein said rein is a Resin 443 manufactured by Union Carbide of Taft, Louisiana.

17. A pretreating solution according to claim 13, wherein said organic solvent is a mixture of cyclohexanone, toluene and dimethyl formamide (DMF).

18. A printing process comprises the steps of:

(a) preparing a negative plate on which a predetermined printed pattern has been realized;

(b) forming a printing layer by coating the surface of the negative plate with a printing composition of claim

1 ; and

(c) covering a printing medium on the top of the printing layer and pressing the printing medium.

19. A printing process according to claim 18, wherein the step (b) of forming the printing layer is performed by at least one of spraying the printing composition on the negative layer, applying the printing composition on the negative plate and dipping the plate into the printing composition.

20. A printing process according to claim 18, further comprising a step of forming a pretreatment layer on the negative plate, prior to step (b) .

21. A printing process according to claim 20, further comprising a step of drying the pretreatment layer before forming the printing layer.

22. A printing process according to claim 21, wherein the drying step is performed at a temperature of about 80 to 100 degrees celsius for about 30 minutes to 2 hours.

23. A printing process according to claim 18, wherein steps (b) and (c) are simultaneously performed.

24. A printing product prepared by the process of claim 18.

25. A printing device comprising: a negative plate supplying device that supplies a negative plate; a printing composition supplying device that applies a printing composition on the negative plate, wherein the printing composition is defined in the claim 1; a printing medium supplying device that applies a printing medium on the negative plate with the printing composition being placed between the printing medium and the negative plate; and a pressing means for applying a predetermined pressure the negative plate and the printing medium.

26. A device according to claim 25, wherein said pressing means comprises a pressing cylinder rotatably engaging a plate cylinder and compressibly transfering a combined assembly of the negative plate and the printing medium.

27. A device according to claim 25, wherein said printing composition supplying device is a nozzle.