IN Brief:
- Definol grades for the EU market exclude borax, although some formulations retain other boron compounds.
- Zerobor is a separate boron-free starch adhesive range specified for corrugator speeds up to 200 metres per minute.
- Purchasing decisions require grade-specific chemical documents, machine qualification and appropriate finished-pack compliance evidence.
Crespel & Deiters says the Definol starch adhesives supplied for corrugated board production in Europe are borax-free, a feature relevant to chemical classification and labelling. The supplier’s 16 October clarification concerns established formulations used to bond corrugated paper structures, including the transit cases that carry food through manufacturing and distribution. Its separate Zerobor portfolio addresses customers seeking adhesives free from boron compounds altogether.
The distinction follows attention to European rules governing hazardous substances and mixtures. A converter purchasing an adhesive must know its formulation-specific classification, safety data sheet, any required hazard label and appropriate workplace handling measures. Crespel & Deiters says its EU-market Definol grades avoid the additional labelling obligations associated with borax under the rules it has identified. The applicable assessment is made for the particular mixture and concentration rather than for starch adhesives as a category. The latest concern includes revised treatment of boron ethanolamine, which can affect safety data sheets and staff training when that substance is present at a relevant concentration. This is why a converter should ask for the current specification of the purchased adhesive, not rely on a general product-family description.
Borax is one member of a wider family of boron compounds. Some Definol formulations use alternative boron-containing ingredients to alter the behaviour of the starch adhesive as it is applied and heated. Zerobor uses a fully boron-free formulation. This gives purchasers two different material specifications: one that excludes borax, and another that excludes boron compounds throughout the formulation. The difference can affect a converter’s chemical inventory, procurement policy and documentation requirements.
During corrugated board manufacture, adhesive is deposited on the crests of a shaped paper medium before a flat liner is joined to it. Water in the formulation helps the starch spread across the contact area; heat and pressure then support development of the bond as the board travels through the machine. Viscosity, penetration into the paper and the speed at which the adhesive develops strength influence board quality. If those characteristics are poorly matched, the line may produce weak bonds, warped sheets or unnecessary waste.
Crespel & Deiters describes Definol as a refined wheat-starch product containing functional ingredients before delivery. According to its product information, the powder can be prepared by mixing with water at room temperature, avoiding a separate cooking step and the need to add some ingredients on site. That preparation method can simplify the converter’s adhesive kitchen, where consistency of dilution, mixing and temperature are important to repeatable application at the glue station.
Alternative boron compounds in selected Definol grades temporarily cross-link starch, influencing gelation and the time available for the adhesive to set. The corrugator needs enough working time for the adhesive to transfer evenly, followed by sufficiently rapid bonding before downstream cutting, stacking and handling. Papers of different absorbency and moisture content place different demands on this sequence. Each mill therefore has to match its chosen adhesive grade with paper composition, application weight, machine speed and heat input.
Zerobor is presented as an option where the whole boron family must be excluded from the formulation. The manufacturer specifies use at corrugator speeds of up to 200 metres per minute, providing a defined starting point for assessing operating suitability. The actual qualification programme also needs to cover bond development, board flatness and the range of flute and liner combinations processed on the customer’s machine.
Food producers encounter corrugated board mostly as cases, distribution trays and other secondary or transit packaging. In those uses the adhesive generally bonds the paper layers rather than contacting food itself. Chemical hazard classification for the adhesive and food-contact compliance for the finished pack are different assessments. If a proposed construction creates direct or indirect food-contact exposure, the converter and food customer need the relevant declarations and evidence for that intended use, taking account of the complete packaging system.
Purchasing specifications can express the choice without ambiguity: require either a borax-free mixture or a formulation free of all boron compounds, alongside the current safety data sheet for the exact grade supplied. Packaging specifications should separately identify board strength, application conditions, storage and transport demands, and any applicable food-contact documentation. The manufacturer’s statement gives converters a basis for distinguishing Definol from Zerobor; plant qualification then establishes the grade and process settings to be used.
Before approving a material change, a converter can compare adhesive preparation time, viscosity at application, bond strength after conditioning, consumption per square metre and performance at its normal running speeds. These process records, together with chemical and finished-pack documentation, provide the evidence needed for procurement approval and repeatable production.
