WO2007004751A1

WO2007004751A1 - Colored retro-reflective material for spray printing

Info

Publication number: WO2007004751A1
Application number: PCT/KR2005/001519
Authority: WO
Inventors: Sang-Yun Jung
Original assignee: Sang-Yun Jung
Priority date: 2005-05-04
Filing date: 2005-05-24
Publication date: 2007-01-11
Also published as: KR20050067367A

Abstract

The detailed composition of the material in the present invention is characterized by high transparent resin with 5~30% non-volatile content compounded in 100 weight percent with glass beads in 20~100 weight percent, tiny metallic particles extracted from vacuum metalizing or mechanical processing in 0.05-5 weight percent, dyestuff in 0.01-3 weight percent and UV-activating hardener in 0.01-5 weight percent respectively.

Description

Colored Retro-Reflective Material for Spray Printing

[FIELD OF THE INVENTION]

The present invention referring to colored retro -reflective material for spray printing, features a characteristic of retro-reflective function in specific colors by one-time spray on the surface of a specific object.

[BACKGROUND OF THE INVENTION]

It is nowadays so commonly noticeable that retro-reflective sheets are attached to safety marks & milestones on the road, safety marks for constructional goods, footwear, apparels, industrial goods, car bumpers, etc. These retro-reflective sheets, especially providing safety & visibility in the night, help pedestrians, drivers and workers to drastically decrease the possibility of falling into safety-related accidents owing to various danger factors. The afore-mentioned retro-reflective sheets, however, as being manufactured in the form of sheet, can only be applied to an object by surface bonding, or stitching, riveting and screwing. Therefore, those sheets are so difficult to attach to the surface of an object, getting more difficult especially when the object representing broken surface, complicated structure and furthermore 3-dimensional curves, and can accordingly be applied to only a restricted area. Because of the above mentioned problems, it's so apparent that the process ability and manufacturing efficiency get worse and manufacturing cost increases as well. The conventional retro-reflective sheets are commonly bonded to the surface of an object after cutting in desired size & form and this process can not enable the sheets to get a tight hold and further causes the sheets to delaminate from the object or deform due to the rain, moisture, dust, minute residues floating in the air.

As another example, stitching retro-reflective sheets to attach essentially calls for the restricted object available for stitching and therefore can not be widely applied to various goods except for apparel, footwear, bag, etc. and the same problem goes with a retro-reflective sheet of striped type.

In the same way, riveting retro-reflective sheets to the surface of an object calls for the object in the form of thin plate and riveting instrument as essential and therefore causes a large limitation in applicable objects and low manufacturing efficiencies. Additionally, screwing retro-reflective sheets to the surface of an object calls for drilling machine, driver, etc as essential and therefore causes a large limitation in applicable objects and low manufacturing efficiencies as well.

Moreover, afore-mentioned riveting or screwing method of attaching retro -reflective sheets to the surface of an object has the critical problem of needing punching hole in the object. For this reason, there are no other methods being applied presently except for attaching retro -reflective sheets to the surface of an object by bonding or stitching.

As a part of efforts to replace retro-reflective sheets mentioned above, various primary development activities are now underway for retro-reflective materials (resin activating, hardener activating types for spray printing) but these completely differ from the invention in material composition and especially fail to complete printing by one-time spray. As for the above-mentioned primary retro-reflective materials for spray printing, it is required to form a light blocking layer first on the surface of an object and keep drying, and consequently repeating spray at least 5 times transparent resin containing glass beads and coloring pigments over the surface of the dried light blocking layer. Under this manufacturing condition, it is also consequently required to spray the 2nd transparent resin after drying the 1st sprayed transparent resin, the 3rd transparent resin after drying the 2nd sprayed transparent resin, the same way through to the 5th one, spray surface shielding resin and lastly keep drying under the dry chamber temperature. According to above, it is quite troublesome in that it takes a great deal of time & difficulties to get a completed artwork (product), provides too low manufacturing efficiencies due to the compounding ratios all the time changing per manufacturing processes, conditions and product characteristics, etc and requires complicated artwork.

Therefore there lies high possibility of defective rate, and meanwhile rises need for high skilled workers, special dry chamber system, and extending manufacturing line, in the end manufacturing cost increases. Owing to the above-mentioned problems, therefore, there has been a rush for the development of new material composition which properly enables retro-reflective function by only one-time spray as the invention.

(SUMMARY OF THE INVENTION]

The present invention is prepared to provide retro-reflective material for spray printing that provides safety function by very simple one-time spray printing only over the whole areas of an object however complicated & broken it may be, without any need of attaching to the surface of an object by stitching, bonding, riveting, screwing.

The detailed composition of the material in the present invention is characterized by a high transparent resin with 5~30% non- volatile content compounded in 100 weight percent with glass beads in 20-100 weight percent, tiny metallic particles extracted from vacuum metalizing or mechanical processing in 0.05-5 weight percent, dyestuff in 0.01~3 weight percent and UV-activating hardener in 0.01-5 weight percent respectively. Glass bead used here can be reflex index 1.93ND whose surfaces are either vacuum metalized or not and 2.2ND whose surfaces are either vacuum metalized or not. And also glass beads can be used by mixing reflex index 1.93ND with 2.2ND as well and dyestuff can be replaced with coloring pigment.

[BRIEF DESCRIPTION OF THE DRAWINGS]

Fig.l, Fig.2, Fig.3 refer to the respective application result in accordance with the present invention [DETAILED DESCRIPTION]

In a detailed description for the ideal application of the invention referring to the drawings attached, it needs to be noted that the described values are not always restricted.

In starting the application, high transparent resin with 5~30% non-volatile content must be prepared. The resin, playing a key role in functioning light permeation and shielding glass beads, needs transparency, high bonding strength to glass beads & dyestuff and strong physical & chemical durabilities. And the non-volatile content of high transparent resin needs to be controlled ranging from 5 to 30 percent because when the content is below 5 percent glass beads are too much exposed out of the resin and therefore fail to get a tight hold, and in turn when the content is over 30 percent glass beads sink too deep into the resin and decreases somewhat transparency and spray effect.

Glass beads used for the invention are compounded within 20—100 weight percent based on 100 weight percent of the above mentioned transparent resin. In other words, a specific gravity of glass bead is far higher than that of the transparent resin, and so even in case of compounding glass bead in the ratio of 100 weight percent against the transparent resin, the quantity of glass bead is still less than that of the transparent resin and therefore used beads are available for compounding and spray printing. Despite of the above laboratory data, however, it has come to an conclusion that the compounding quantity of glass bead needs to be controlled within 20~100 weight percent based on 100 weight percent of the transparent resin as specified above. Glass beads used here can be reflex index 1.93ND whose surfaces are either vacuum metalized or not and 2.2ND whose surfaces are either vacuum metalized or not. And also glass beads can be used by mixing reflex index 1.93ND with 2.2ND as well.

Re-explaining the process, the invention can adopt per the specific application purposes mixed glass beads of reflex index 1.93ND and 2.2ND or individual ones of reflex index either 1.93ND or 2.2ND. And each glass bead can be either vacuum metalized or not. The reflectivity gets better with vacuum metalizing treatment on the surface of glass bead but in case high reflectivity is not necessary normal glass beads can be used without vacuum metalizing treatment. By the way, adopting glass beads of reflex index 1.93ND and 2.2ND has resulted from the spray performance & laboratory evaluation that those reflex indexes meet the needs for manufacturing retro-reflective material for spray printing. The glass beads of the rest reflex index have been found to have problem with reflectivity and hard to make a quality product with,

In mixing glass beads of reflex index 1.93ND and 2.2ND, the compounding ratio can be controlled as intended, but the more ratio of 2.2Nd beads is used the better reflectivity is coming up. The further description will follow for this.

In the next, it is required to put tiny metallic particles extracted from vacuum metalizing or mechanical processing in 0.05~5 weight percent based on 100 weight percent of high transparent resin. These tiny metallic particles plays a function of reflecting the colors of dyestuff to be described hereafter and can be replaced with normal types of minute aluminum particles, and other various types of metals such as copper, gold, silver, etc. As tiny metallic particles extracted from gold, silver, copper have individual unique colors, the retro-reflective material of the invention represents various coloring effects along with the colors of dyestuff to be described later. Additionally, it has come to an conclusion that the compounding quantity of tiny metallic particles provides little application effect in less than 0.05 weight percent based on 100 weight percent of high transparent resin, and on the other hand in over 5 weight percent causes trouble with spray function, decreases bonding strength to glass beads thus leading to high manufacturing cost.

Nextly 0.01~3 weight percent of dyestuff needs to be put into 100 weight percent of high transparent resin. It has come to an conclusion that more desirably the particles of dyestuff need to be very tiny or in nanometer. In case the particles of dyestuff are not completely tiny, then it's quite unavailable to get the refined & even colors. But it should also be noted that dyestuff used in the invention can be replaced with coloring pigments of fairly tiny particle.

In the next process, 0.01-5 weight percent of UV-activating hardener needs to be put into 100 weight percent of high transparent resin. The reason for the invention to adopt UV-activating hardener is to greatly improve manufacturing efficiency and productivity enabling quick drying & curing only by having the sprayed object exposed to sunlight or UV light right after spray printing without any specialized drying chamber or technology applied. In the test it has been found that it's desirable to put 0.01-5 weight percent of UV-activating hardener into 100 weight percent of high transparent resin.

Specified below are the detailed descriptions for the application results of the invention.

Firstly, Fig.l (first application example) shows a process where 3 weight percent of UV-activating hardener is put into high transparent resin with 25% non-volatile content making UV-activated high transparent resin(l). Glass beads(2) used here were reflex index 2.2ND with aluminum metalizing treatment on the surface and put in 50 weight percent to 100 weight percent of high transparent resin. In this case normal glass beads can also be used without metalizing treatment. Dyestuff was used in yellow in the compounding ratio of 1 weight percent to 100 weight percent of high transparent resin. As tiny metallic particlesO) copper was adopted and put in the compounding ratio of 2 weight percent to 100 weight percent of high transparent resin.

Fig.l refers to the material of the invention with the above-mentioned compounding ratio spray printed on the surface of an object(4) where glass beads(2) sinks into UV-activated high transparent resin(l) while tiny metallic particles(3) sit under glass beads. In other words, being composed of 25% of non-volatile content, UV-activated high transparent resin(l) does not lower it's layer under the top of glass beads after drying & curing by exposure to UV light , thus letting glass beads sink into the resin. Per the application example as in Fig.l, UV-activated high transparent resin(l) keeps glass beads safe away from external shock or abrasion and therefore it is recommended to apply the invention for the product calling for physical & chemical durabilities. Another fact found from Fig.l was that even when UV-activated high transparent resin(l) is covered with water, retro-reflective function was well performed. Moreover when comparing an object(4) in Fig.l to road marking line, it is quite apparent that even when the road is covered with the rain (even when the surface of UV-activated high transparent resin(l) is covered with the rain) retro -reflective function can be well performed and therefore the application example of Fig.l can also be adoptable to road marking line. As a further test result it has also been verified that while driving in the night with front headlight on driver can catch retro -reflective light out of the invented material. The test was conducted in the rain as well with the same result as above. Retro -reflective color shown in this case was gold out of mixture of copper and yellow dyestuff.

On the other hand Fig.3 represents the 2nd application example where high transparent resin is composed of 15% of non-volatile content and the rest formula is the same with Fig.l (the 1st application example) and as the non- volatile content is lower than that of Fig.l (the 1st application example) therefore the surface of UV-activated high transparent resin(l) almost meets the top of glass bead(2) but it does not mean positioning must be exact as per the figure and some variation can arise accordingly. The example can be applied to the product requiring less physical & chemical durabilities compared with Fig.l and the test result showed was similar to Fig.l except for slightly lowered retro-reflection. In the afore-mentioned 1st & 2nd application examples glass beads used were reflex index 2.2ND but 1.93ND can also be adopted, however in this case it should be noted that the reflectivity of 1.93Nd decreases compared with 2.2ND.

Fig.2 represents the 3rd application example of the invention where glass beads(2)(2a) are exposed out of the surface of UV-activated high transparent resin(l). The compounding formula of the example indicate mixing ratio of glass beads of reflex index 2.2ND(2) and 1.93ND(2a) ranging from 1:1 to 3:1. Glass beads used here can be vacuum metalized or not. Other compounding formula applied are high transparent resin of 10% non-volatile content and the rest ones the same with the 1st application example. Specifically in the 3rd application example, no problem was found in drying & curing of UV-activated high transparent resin(l) by putting lower content of UV-activating hardener to high transparent resin than the 1st application example.

As shown in the 3rd application example, glass beads(2)(2a) are exposed out of the surface of UV-activated high transparent resin(l) and therefore the invention can be properly applied to the normal products calling for less physical & chemical durabilities, rather preferably to those requiring strong retro-reflection.

In the tests of the invention specified above, the total thickness of the invented material spray printed on the surface of an object(4) ranged from 30 to 100 micron using spray gun. It has also been noticed from the tests that spray printing by inserting the invented material into portable spray can leads to the same result as one by spray gun. Therefore it is quite apparent that the invented material can be introduced in the market after inserting into portable spray can.

In other application test, almost the same result has been found when laminating on the surface of an object(4) by painting method in stead of spray printing and therefore it has come to the conclusion that the invented material can be applied to the surface of an object by various methods not restricted to spray printing. And further it has been found that as a result of mixing with the invented material, normal paints came to get retro-reflective function thus the invented material maintains retro-reflective function even after mixing with other materials with some declines in original function.

As for other process tests related, it has also been verified that the invented material can be used for screen printing and other machinery printing where no problems were raised in retro-reflective function and durabilities. And more apparently it has been noticed that however broken & complicated or 3-dimensionally curved the surface of an object(4) may be, the invented material can be printed over the whole areas of the surface by very simple one-time spray printing only and also successfully represents safety function.

From the above mentioned so far, it has already been noticed that the invented material, differently from normal retro-reflective material of resin activating, hardener activating types for spray printing, can represents excellent retro -reflective function by very simple one-time spray printing, helps reduce working time by around 80%, increases retro-reflection by 30%, and at the same time reduces defective rate by 99% and cuts down the facilities cost by more than 60% never requiring specialized drying chamber system & long manufacturing line. And as shown in the 1st, 2nd application examples, conventional retro-reflective material of resin activating or hardener activating types for spray printing does not provide enough side retro-reflection effect, especially in the rain or water. From all the mentioned above, the retro-reflective material of the invention could be claimed as brand-new material in retro-reflective business field.

[INDUSTRIAL APPLICABILITY]

The invention specified above provides new material for spray printed reflective products which creates excellent retro-reflective function on the surface of various types of objects with complicated & broken structure by simple one-time spray printing only, enables to perform the manufacturing process in very easy, simple and economical way with little defective problem that has never been available in sheet types of retro-reflective materials and conventional spray printing technologies applying resin activating & hardener activating processes and therefore could be called as making a drastic turning point in contributing to retro -reflective business in industrial fields & application technologies related.

Claims

What is claimed is;

1. Colored retro -reflective material for spray printing which is characterized by high transparent resin of 5-30% non-volatile content compounded in 100 weight percent with glass beads in 20-100 weight percent, tiny metallic particles extracted from vacuum metalizing treatment or mechanical processing in 0.05—5 weight percent, dyestuff in 0.01-3 weight percent and UV-activating hardener in 0.01-5 weight percent respectively.

2. Colored retro -reflective material for spray printing in claim 1 which is characterized by the glass beads whose reflex index is 1.93ND and whose surfaces are either vacuum metalized or not.

3. Colored retro-reflective material for spray printing in claim 1 which is characterized by the glass beads whose reflex index is 2.2ND and whose surfaces are either vacuum metalized or not.

4. Colored retro-reflective material for spray printing in claim 1 which is characterized by compounding glass beads of reflex index 1.93ND and glass beads of reflex index 2.2ND,

5. Colored retro -reflective material for spray printing in claim 1 which is characterized by dyestuff replaced with coloring pigments.