Teikoku Printing Inks Mfg. Co, Ltd.



Q&A regarding Teikoku Printing Inks products

What are the meanings of X and Q used in the ink names such as IPX, INQ, FMX, etc.?

X and Q are used to designate isophorone-free inks.

What are RoHS, WEEE, and ELV?

The official name for WEEE is Waste Electrical and Electronic Equipment Directive and RoHS is Directive for Restriction of the use of certain Hazardous Substances in electrical and electronic equipment.

The meaning of WEEE is the directive for waste disposal of products which contain 6 types of substances that are in electrical and electronic equipment that are hazardous to the environment and to humans. The RoHS is the directive which bans the use of these restricted substances in the production of such equipment.

Restricted substances are lead, cadmium, mercury, hexavalent chromium , polybrominated biphenyl, and polybrominated diphenyl ether. Unlike polybrominated biphenyl and polybrominated diphenyl ether, the other four substances are restricted also in automobile-related products (ELV order).

These directives will be applicable, if the products are produced for distribution in European countries. These directives affect non-European companies who export to Europe. Moreover, even if a company does not directly export its products into EU countries, exported products will be required to certify that these restrictions have been met.

How do you use IR transmittable ink (IR Transmitting Ink) ?

After printing IR transmittable ink (IR Transmitting Ink) onto transparent PC or PET substrate sheet, the ink has the special function of blocking the shorter wave-length visible rays and ultra violet rays and allows the longer wave-length infrared rays to penetrate. One example of an application that this ink is used for is the signal receiving filter of remote control devices.

What is the meaning of mirror effect technology?

Mirror ink is applied onto PC or PET material sheet by screen printing, which results in a mirror effect similar to metal plating.

Is Mirror Ink patented?

Yes it is patented. (Japanese Patent Registered Number 3151606)

The patent covers the manufacturing method of Mirror Ink, making prints with Mirror ink and making prints with similar ink.

What is the main difference in features between MIR 9100 Mirror Silver and MIR 8100 Mirror Silver?

The differences are in mirror effect, viscosity, adhesion and on-stencil stability. These differences are further explained below.

Mirror Effect:
MIR 9100 was designed to have better mirror effect than MIR 8100 Mirror Silver Ink. It has better mirror effect than traditional mirror inks.
MIR 9100 has higher viscosity for printing by ordinary clamshell press. The higher viscosity allows easy printing of fine characters and negative letters.
MIR 9100 ink adheres better than previous Mirror Inks.
Stability on Stencil:
MIR 9100 has excellent on-stencil stability. Since it contains a slow drying solvent, there is less evaporation and clogging of the stencil. It can print fine lines and letters consistently.
In what cases should additives be used?

It depends on various factors. A case by case explanation follows.

To Decrease Mirror Effect:
By adding 0-30% of MIR 9001 Mirror Effect Decreaser, the mirror effect can be adjusted.
To Improve Adhesion:
Adding 0-30% MIR 9000 Medium Base will improve adhesion. Use this additive cautiously because the mirror effect will be decreased as the quantity of additive is increased.
To Increase Covering Power:
Following countermeasures will help.
(1) Add 2% MS-90 Defoamer. This will allow the ink to flow through the stencil better, increasing the covering power.
(2) Add 5-10% MIR Medium Base. When used in conjunction with the MS-90 Defoamer as in step (1), better covering power will result.
To Print on a Hard-to-print Substrate:
Adding 1% of 106 Catalyst will be effective when printing on hard-to-print substrates such as hard coated acrylic resin.
For Clear Print of Negative Letters and Fine Lines:
Add 2% SM-90 Defoamer
Add 5-10% MIR 9000 Medium Base
How can we increase covering power?

Use squeegee with 70 degree hardness and rather high printing pressure. When printing with Mirror Ink, the covering power may not be as good as what is shown in print samples. An effective measure to increase covering power is to use a harder squeegee. As the Mirror Ink has less resin in it, ink transfer to the substrate is rather lighter than with ordinary screen inks.

Therefore changing printing conditions is sometimes effective.

* Recommended printing conditions are as follows
Squeegee hardness should be 70 degrees. / Printing pressure should be slightly higher. / Doctor pressure should be slightly higher as well.


Is over-printing required?

Yes. Over-printing is necessary not only to improve scratch resistance but also to improve resistance to other elements. As Mirror Ink is affected by moisture, the aluminum layer might change the color if not over-printed.

When drying the print in a line oven it sometimes appears hazy. Why does this occur?

Upon further investigation with the customer, the printing conditions that caused this hazy appearance were discovered to be as follows. Mirror Ink was printed with a cylinder press and dried in a line dryer at a high temperature, thus the resultant hazy effect. The reason being: the initial drying at a high temperature. The recommended drying condition is 30 minutes at 80°C, but in this case the line dryer was used for 2 minutes at 100°C. When the substrate was dried at this high temperature with a great deal of solvent on it, the substrate was affected adversely and turned white.


How can we dry in a line dryer without getting haze?

You may avoid the hazy effect with following countermeasures:

1. Lower the temperature of the line dryer. (lower than 80°C)

2. If the line dryer has several drying sections, set the temperature at the entrance section as low as 40-60°C and evaporate the solvent as much as possible (preferably 80-90%).

3. Then the printed matter can be dried at 80-100°C and evaporate the solvent completely. This should result in a good mirror effect.


Q&A regarding Printing and Forming

What is screen printing?

Screen printing is a type of stencil printing which uses a technique of duplicating the image from a design made on mesh stencils.

When printing ink goes through the mesh, it transfers the image onto the substrate material. Other than air and water, any substrate materials are printable. Not only flat surfaces, but also curved, specially shaped, and molded products are suitable for screen printing.

When over-printed with a black ink, we often have pinholes. How can we eliminate the pinholes?

See the list below for causes of pinholes:

1. The first layer is too thin (less than 5 µ)
2. Too much dilution of the ink (more than 20%)
3. Too much squeegee pressure
4. Under layer is pale colored, such as a medium based color
5. Any combination of these causes

What are the standard drying conditions?

In multi-color printing, primary drying would be done after each color is printed. After the final color is printed, the final drying should be done according to the conditions listed in the catalog. If the color printed ink is a "two-pot" ink the final drying should be done after the printing of the Binder.

Why there is "Primary" drying and "Final" drying?

Residual solvent at the time of injection may cause ink flow and insufficient adhesion. To prevent these malfunctions, residual solvent must be evaporated through a "Final" drying process.

When we extended the primary drying time, pinholes and cracks resulted. How can we eliminate them?

With one-pot inks, if the primary drying time is too long, the solvent of second ink penetrates the first color layer and makes pinholes.

With two-pot inks, if the primary drying time is too long, a curing process occurs. Thus when the second color is printed, the first color ink layer wrinkles and looks like cracks. The countermeasure in either case would be to shorten the primary drying time.

We found that sometimes when we peel off the print from the injected resin, ink remains on one side or sometimes on both sides. Why does this occur?

In the case of ink remaining on the substrate, adhesion to the injected resin is poor. When ink remains on the injected resin, the adhesion to the substrate is poor. This is delamination. When ink remains on both sides, adhesion to substrate and injected resin are good, but the cohesion of the ink layer is poor. This is a cohesion failure.

The printed layer peeled away from the injected resin. What should we do?

This may be due to a mismatch of ink, substrate and the resin. Please contact our representative.

We have always had good adhesion, but suddenly peeling has occurred. What should we do?

Please check the following:

1. Thickness of the ink layer.When ink layer is too thin adhesion might be decreased.

2. Drying conditions of the ink layer.When drying time is not adequate, the strength of the ink layer becomes poor and cohesion failure may occur.

3. Existence of additives such as defoamers.Some additives might decrease the adhesion.

4. Temperature of the melted resin. If the temperature of the melted resin is too low, the binder and ink layer will not melt and this causes insufficient adhesion. Please set the temperature of melted resin and mold at a bit higher level.

What is the meaning of FIM/IMD?

The abbreviations, FIM and IMD, stand for Film Insert Molding and In-Mold Decoration. For these methods, the printed film is set into the mold and molded with molding resin as the finished product.

What types of forming are there?

Typically, there are Vacuum Molding, Air-pressurized Molding, Press Molding, and High Pressure Molding.

Using FIM/IMD method, can you give us some examples of substrate film and molding resin combinations?

PC, PET, and Acrylic substrate sheets are suitable. Suitable resins are PC, PMMA, PC/ABS, AS, etc. However, PP and Olefin are currently difficult to use because they do not have good adhesiveness to the substrate materials.

From a recycling point of view, are there any actual cases of the same resin being used for both the substrate material and the molding resin? If so, can you give some examples?

ISX Ink for PC material sheet with PC resin is theoretically possible, however we do not have any actual cases of this as yet.

What is the difference between Film Insert Molding and In Mold Decoration? Do you use different inks for each?

For the FIM method, the printed surface will be placed between the substrate sheet and the resin. On the other hand, for IMD method, the printed surface will appear on top of the adhered layer of the substrate sheet and the resin. The type ink will depend on the application and your requirements.

What is the largest size that you can use for the Insert Molding Method?

Theoretically, it depends on the capability of molding machine. However, there is an elongation limit of the substrate sheet; it varies depending on the printing materials you are using.

Can you give some examples of the type of industry where a combination of ink and molding method is being used? What would be the actual finished product?

The main industries will be automobile interiors, amusements, and home appliances. Their finished products are such items as speedometers, pinball game machines, water boilers, TVs and possibly as cover material in various other areas.

Do you have any restrictions when you use functional inks for molding inks?

There are some limitations of color hue, glossiness, and other properties. Sometimes, Teikoku Inks is unable to meet a customer’s requirements due to the design of the product.

What is a binder?

It is a binding layer, which enhances the binding between the injected resin and the inserted print matter, principally printed with 2 pots of curing ink.

Does ISX Ink need a binder?

No, it does not need a binder because ISX ink is a one-pot ink and has good adhesion to injected resin.

What is the difference between IMB-003 Binder and IMB-009 Binder?

IMB-009 Binder is designed for Mirror Inks. When printed on MIB Ink, which is an overprint ink for Mirror Inks, it does not harm the mirror effect. Besides that it has better heat resistance. It is especially suitable to be used with PC resin. IMB-003 Binder is a general use binder and has good adhesion to a wide variety of resins such as PC, PC/ABS, ABS, PMMA and AS.

Why do two-pot inks need a Binder?

When cured, a two-pot ink layer has a cross-linked structure and good heat resistance, in other words it is hard to melt at the high temperature of the injected melt resin. Therefore it has inferior adhesion to injected resin. The binder layer between the pattern printed layer and injected resin can strengthen the adhesion between them.

At the time of printing Binder, excessive drying of under layer ink may cause decrease of peeling strength. Be sure to print continuously until Binder before final drying.



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