THE flexible packaging industry

Excerpt: Resin industry are to satisfy different quality requirements from each customer and to assist them in formulating inks which satisfy their customer needs of trouble free printing of designs

Introduction

THE flexible packaging industry today is very dynamic. Varieties of substrates are introduced into the market every day with different surface properties.

Better and faster printing techniques are available today which are designed to give superior print quality with less down time, allowing the converter to run more and differentiated jobs in a shorter period of time.

Package designs are not only meant to please the eye with its glossy photo-like finish but also to preserve its contents.

Food packages for microwave cooking not only need to protect the food during storage but also need to have good heat resistance. The beverage packages require resistance to the environment found in refrigerator storage and handling. To meet the demands of the packaging industry, the ink manufacture today needs to formulate inks that can be used for multiple applications.

Non Toluene and Non MEK based polyurethane resin imparts special c h a r a c t e r i s t i c s t o i n k s y s t e m , such as:

Excellent dot transfers resulting in 

superior print quality.  Very low residual odor- lower solvent retentions For enquiries : email: author.ppp@gmail.com

Non toluene & non methyl ethyl ketone-polyurethane ink binder for liquid inks

 Environment friendly (non use of Toluene/MEK) Thus a polyurethane resin (Ink binder) plays a very important role as one of the key component for printing inks. The ink binder not only provides adhesion properly to the substrates but is also responsible for imparting many other properties, like heat resistance, anti- blocking, etc along with other ingredients. Polyurethane base ink binder basically divided in three categories

  1. Polyester based PU ink binder.
  2. Polyether based PU ink binder.
  3. Amine terminated polyurethane ink binder. Each kind of backbone has its own advantages like polyester based has better thermal stability and chemical resistance, polyether based binder are good in flexibility and alkali resistance, amine terminated polyurethane resin are film forming with good flexibility with or without Toluene/MEK/IPA and Ethyl acetate.

High demand of Eco friendly PU ink system for food packaging, a Non Toluene and Non MEK based resin was introduced in the market to fulfill the need of the packaging industry. Chemistry

The polyurethane ink binder is formed from prepolymer comprising a blend of

PU Ink Binders

1 2

PK Nautiyal , SK Dang

1 2

AGM-R&D, Sr. Vice President Uflex Ltd (Chemical Div). Noida, Uttar Pradesh, India

high molecular weight polymeric diols and low molecular weight diol reacted with diisocyanates which is further extended with a diamine to form polyurethane.

To make Polyurethane polymers generally bi-or higher functional (isocyanate or hydroxyl containing) monomers are used. The hydroxyl and the isocyanate groups combine through addition to form a urethane linkage:

ROH + R'NCO ROC (O)N(H)R' (where R and R' are alkyl or aryl groups)

Generally PU resin binders are supplied in 40% and 30% solids concentrations.

These polyurethane inks can be used for Gravure or Flexo printing applications. Suitable solvent combination alcohol/ester solvents may be used d e p e n d i n g o n t h e p r i n t i n g process/substrates etc.

Pu ink binder characteristics

Only EA & IPA in Resin 100% aliphatic   No PAA (Primary Aromatic Amine)  Film forming grade Good pigment wetting ability   Can do pigment grinding  Good color strength development Mainly for gravure reverse printing   Excellent non-yellowing property and light resistance

PU Ink Binders

Excellent heat and chemical 

resistance  Good transfer property, good half tone reproduction  Excellent adhesion property for different Substrates Good blocking resistance   Excellent solvent release property, very low solvent retention Low viscosity, good re solubility  After Printing and lamination:  High lamination bond and seal strengths Excellent heat and chemical  resistance Boiling resistance (for retort application)  Good compatibility with different adhesives, especially for the solvent free adhesives

Conclusion

The main challenges of resin industry are to satisfy different quality requirements from each customer and to assist them in formulating inks which satisfy their customer needs of trouble free printing of designs on various substrates at desirable/high speeds as well as issues related to regulatory compliances, safety and cost considerations.

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Aroma with Plastics

2009 POPULAR PLASTICS & PACKAGING 73  POPULAR PLASTICS & PACKAGING  MARCH 2010   MARCH 74 2010 POPULAR PLASTICS & PACKAGING 73  POPULAR PLASTICS & PACKAGING  MARCH 2010  74  MARCH 2010

POPULAR PLASTICS & PACKAGING 75 POPULAR PLASTICS & PACKAGING   MARCH 2010  MARCH  76 2010 POPULAR PLASTICS & PACKAGING 75 POPULAR PLASTICS & PACKAGING   MARCH 2010  76 MARCH 2010 