subject: Solvent Complex Process Control Points And Frequently Asked Questions - A Solvent, Complex Process, [print this page] No Solvent Complex process began in the 20th century 70's, currently in Europe and the United States market has occupied an important position, compared with the solvent complex process, has the following advantages.
(1) the production does not use solvents, to avoid environmental pollution.
(2) to minimize fire and explosion hazards.
(3) composite products after the residual solvent is more suitable for very sensitive to the smell of goods Package .
(4) Solvent-free composite device is not drying, reducing energy consumption.
(5) solvent-free composite device is equipped with On-line corona treatment unit, and the corona subsided, high content of slippery agent Film Good composite properties.
(6) combined speed, high production efficiency.
(7) integrated low cost. However, the actual production, because the initial solvent-free adhesive viscosity is low, the operation control more difficult, prone to all kinds of quality problems. Here, the writer's solvent-free complex process control points and to discuss common problems and all.
Process control points 1. Composite substrate Present, solvent-free compound commonly used substrates are mainly BOPP , PET , O PA , VMCPP, VMPET, CPP, PE, aluminum foil. Compound will generally be rigidity, Coating Of good materials (PET, BOPP, OPA, VMPET, etc.) on the primary unwind station; be easy to stretch the material (PE, CPP, VMCPP etc.) on the unwinding station deputy. But is not static, you can choose according to the actual production flexibility, such as Print Film and aluminum composite, in order to ensure the quality and production efficiency of composite, aluminum materials can be put into the paper the main station.
2. Adhesive selection Solvent-free adhesives are mainly one-component moisture curing type adhesive, two-component coating without cold Solvent Adhesive, two-component coating type reverse thermal adhesive, UV curable adhesives such as several. Select adhesive factors to consider when there are many, first of all the types of packaging contents and types of thin film materials used; Secondly, if the printing Ink And the adhesive contact, but also consider the compatibility between the two; once again, sealing the peel strength requirements and conditions on the choice of adhesive is also greatly affected.
Addition, it requires attention to two issues: First, MD I kind of isocyanate compounds through the inner membrane to the inner surface of the gradual migration of water vapor reacts with the anti-sealing layer of polyurea formation, influence Bags Sealing quality, when Polyethylene Poor quality or adhesive film was prone to this problem choose not to, especially when using the two-component adhesive is more to note. Second, higher levels of composite films slippery agent, because of slippery agent migration into the adhesive layer, peel strength may appear poor, poor sealing, friction coefficient increases and other issues affecting their Packaging Line The operational. Therefore, in the composite of such films must pay attention to choose a suitable adhesive.
3. Tension Control
Complex process in solvent-free, tension control is extremely important and must be very precise. Unwinding tension control, including the main tension adhesive film after the tension, the Deputy rewinding tension, winding tension, winding taper aspects. In general, the film coating to be slightly larger than the main tension after the unwinding tension, unwinding winding tension slightly larger than the tension, taper rolling controlled within 20% as good. Films for different materials, composite parts of the process of tension are also different sizes and even different manufacturers of the same material of the film, the tension should also slightly adjusted. Such as the PA / PE composite film structure, PE film tension between roughly 1.5 ~ 2.5N, PA membrane tension can be controlled according to the actual situation between 7 ~ 15N.
