SIGMA INKS

TECHNICAL INFORMATION

SIGMA inks are formulated for flexo and gravure printing of coextruded polypropylene films that will be used for packaging snack food products such as potato chips and other fatty foods. They exhibit excellent print qualities on modern high speed presses giving good adhesion, low odour and low retained solvent characteristics.

PROPERTIES:

Heat resistance - suitable for many ink-in-seal applications. Product resistance towards animal and vegetable fats. High slip. Good scuff resistance. Low odour and solvent retention.

SUBSTRATES:

SIGMA inks are suitable for printing on Co-extruded polypropylene films and treated LD, and HD polyethylenes. Treatment levels should be between 38 and 44 dynes to ensure good adhesion. Sigma inks can also be printed onto coated polypropylene films such as MB777. However, care must be taken to ensure that the press driers are working efficiently and that the recommended reducers are used for reduction, to avoid the possibility of solvent retention in the film coating. Glycol retarders are not recommended for these applications.

COLOUR RANGE:

SIGMA inks are available in a wide range of colours. The pigments used have reasonable lightfastness but may not be suited to extended exposure to direct sunlight. If this property is required it should be stated at the time of ordering and pigments of appropriate fastness will be utilised. Inks may not be resistant to all post printing conditions. Special requirements should be specified at time of order.

PRESS SPEED:

SIGMA inks may be run at speeds of 50 to over 200 m/minute dependent upon press drying capabilities and the solvents used for reduction.

ROLLERS AND STEREOS:

Being alcohol rich, SIGMA inks for Flexo application can be run with most normal rubber rollers and stereos. Photopolymer plates may also be used with high alcohol diluents, but this should be discussed firstly with our technical service personnel to ensure the correct formulation is being supplied for these plates.

REDUCTION:

Normal: 2:1 Ethanol/Ethyl Acetate Slow: 2:1 N-propyl Alcohol/N-Propyl Acetate These can be mixed in ratios of 2:1 alcohol to ester for gravure printing or 4:1 alcohol to ester for flexo printing. For printing on MB777 low ester reducers are always recommended with maximum 20 % ester in the reducer to avoid solvent retention. Isopropyl Alcohol can be used to replace Ethanol. However, this is not recommended and may be detrimental to the printability, particularly with gravure printing.

WASH UP:

Alcohol/Ester blends.

Note:

This information has been carefully compiled from experience gained in field conditions and detailed laboratory testing. However, the product's performance and it's suitability for the customer's purchase depend on the particular conditions of use and the material being printed. We recommend that customers satisfy themselves that each product meets their requirements in all respects before commencing a print run. Since we cannot anticipate or control the conditions under which our products are used, it is not possible to guarantee their performance. We would point out that the information provided here is only a recommendation, and may need to be altered to suit the conditions and efficiency of the equipment employed. Coates Lorilleux ink products are not designed for use in conjunction with those of any other ink-maker or similar supplier unless agreed to in writing.