Screen printing, forming

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.

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.

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.

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.

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

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.

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

Ink attached so far but it suddenly peeled off. I don’t know what to do.
Please check the following.
(1) Film thickness of printed ink layer
Thinner binder layer tends to have weaker adhesion.
(2) Drying conditions for printed ink layer
If ink doesn’t dry sufficiently, the strength of the printed ink layer becomes weak and cohesive fracture will occur.
(3) Are there any additives such as defoamer contained in ink or binder?
If additive such as defoamer is added in ink, ink’s adhesion to resin tends to be weak.

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.

We recommend reading the FIM/IMD technology White Paper:
(1) FIM/IMD – 3 Process stages & Benefits
(2) FIM/IMD – Screen printing process –
(3) FIM/IMD – Forming process –
(Final) FIM/IMD – Injection process –

We recommend reading the following reports:
Environmentally Friendly FIM/IMD Ink and Binder
IMB-HF006 Binder (Halogen Free, Environmentally Friendly Binder for IMD/FIM)
IPX-HF Screen Ink (2 Pack Halogen Free Environmentally Friendly Ink for IMD/FIM)
2 Pack Ink for FIM/IMD Applications
Adding High Value to Products with FIM/IMD (Part 3)
Adding High Value to Products with FIM/IMD (Part 2)
Adding High Value to Products with FIM/IMD (Part 1)
Teikoku Provides New Color and New Function to Plastic Products
FIM/IMD Technique: FIM Ink Design Technique,Optimization Technique of Forming Conditions

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

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.

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.

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.

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.

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.

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.

We recommend reading the following reports:
IMB-HF006 Binder (Halogen Free, Environmentally Friendly Binder for IMD/FIM)

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

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.

In order to improve printing quality, it is necessary to use the most suitable catalyst according to the ink used, printing environment, and expected printed ink layer properties.

Please refer to the following technical report for information on the optimal catalyst and the amount to be added.

Related Link
Introduction of Catalyst

For printing on glass substrate, GLS-HF ink series , a two component type Halogen Free ink for printing on glass substrates is recommended.

The GLS-HF ink series is characterized by the fact that it is an organic ink, unlike the inorganic inks conventionally used for glass substrate printing.

Therefore, GLS-HF ink has excellent functions to solve the problems of inorganic inks (burning type ink) such as “lack of color variation” and “environmentally hazardous substances”, etc.

Related link
Introduction of GLS-HF ink (1)

We would like to introduce the high value-added glass substrates for flat panels, touch panels, etc. using the technologies we offer.

From a design stand point: *Realize various color variations on glass substrates. *High opacity Black and high opacity White that can be applied to window flame of touch panels.

From a function stand point: *Providing IR transmittance functions, *Malfunction prevention by non-conductive black, *Reduction of environmentally hazardous substances, etc.

Related links
Introduction of IRX-HF
Introduction of GLS-HF (4)
Introduction of GLS-HF (3)
Introduction of GLS-HF (2)
Introduction of Functional Black ink

In the manufacturing process of flat panel displays, double-sided adhesive tapes are used to bond functional films and protective films that prevent panels from getting dirty or scratched. Replacing this double-sided tape with the UV adhesive that we offer could lead to a reduction in manufacturing costs. This is because bonding with this double-sided adhesive tape requires many processes, including “cutting the double-sided adhesive tape to fit the bonding surface,” “bonding the double-sided adhesive tape,” and “removing the release paper”. In addition, there is the problem of waste such as release paper and excess portions when matching the adhesive to the bonding surface. However, by using UV adhesive, it is possible to solve the problem of the number of processes and the problem of waste at the same time.”