Paper Coating For Water Proof

Paper coatings, which are functional coatings that impart qualities such as printability and glossy surfaces to paper, are also water-proof and moisture-proof, as well as grease and mould resistant.

Although paper does not have high levels of wet-strength, it has the potential to be a solid water container when coated, and can retain its waterproof qualities for a number of months, he explains.

Coating applications are used by paper-using industries including fast food stores, sectors making use of paper bags and magazines.

Food industries use coated paper to prevent food contamination and pharmaceutical companies are legally required to have mould-resistant coatings on medicine packaging.
Paper coatings made from aqueous emulsions are applied to a paper substrate surface, and act as a barrier that prevents moisture and grease from soaking into absorbent packaging materials.

The waterproof coatings used in general packaging are repulpable, compostable, biodegradable, and are food-grade compliant. Coated products have low environmental impact and harmful solvents do not evaporate owing to water-based coating chemicals.

POLYETHYLENE
Polycoated paper is imported from the US, Europe and China and large amounts of polycoated paper are produced in South Africa.

Plastic, normally made from polyethylene, is a direct derivative of crude oil, and owing to rising costs of this commodity, alternatives to using plastic or wax for paper coating have been developed to make paper waterproof.

Polyethylene coated papers, usually about 12 microns thick, have negative implications for the environment because they cannot be recycled and repulped, and high costs are incurred by the local economy from millions of dollars worth of oil imports which are turned in polyethylene.

Servo for flexo printing machine

Servo drive and control technology has made mechanical line shafts, gearwheels, gearboxes and cams redundant for designers of flexo printing machines. Servo drive and control technology has made mechanical line shafts, gearwheels, gearboxes and cams redundant for designers of flexo printing machines. The high precision synchronisation which is possible with controls such as Rexroth Indramat's SYNAX200, means that all machine units are operated by single drives. This includes linear motion sequences such as the ink-deck pre-positioning of the anilox and printing cylinder as well as gravure, gluing and processing units. It also covers the printing cylinders, impression cylinders, screen rollers, inking and coating units, paper in-feeds and outfeeder.

The first drive and control solution for seven colour in-line flexo printing was produced by Rexroth Indramat in 1996. Benefits accruing from this include infinitely variable format length because repeat length grading, previously given by gear pitch, is eliminated. The removal of format gears and the gearmesh procedure considerably reduces setting up time. Most leading manufacturers of flexo printing machines have now developed new machine designs with servo drive technology. For example Fischer and Kreckes' new machine for flexible packaging features sealed chamber doctor blade assemblies, designed for easy handling, ceramic anilox rolls for precise and constant ink transfer and servo AC motors in all relevant drive positions.

Picture downloaded from : www.printerspost.com.au/Article.aspx?id=704

Asset Management of Medium and Small Wastewater Utilities

The effective management of wastewater infrastructure assets, such as collection systems, treatment works and disposal or recycling operations is a challenging issue for utility companies. The aim of effective management is to minimise the cost of ownership and operation, whilst providing an acceptable level of service to all customers and conform to regulator directives. Effective asset management is a function of operational, technical, environmental and financial parameters. This challenge is sometimes further complicated for small and medium size networks and facilities, where assets are geographically dispersed but must be managed to the same operational and quality standards as large systems.

Effective planning and design of a disparate set of wastewater collection and treatment assets must incorporate appropriate tools and techniques, such as life cycle analysis of decentralised systems, process design issues and human factors. Day to day management of these assets requires the development and implementation of efficient systems of work, all underpinned by robust data and data management systems. The rise in importance of effective asset management over recent years has posed challenges for engineers, academics and industrial researchers alike. Within this context, a specialist conference on "Asset Management of Medium and Small Wastewater Utilities" will offer significant knowledge transfer and networking opportunities to benefit all stakeholders. This conference is organized by the Laboratory of Ecological Engineering and Technology, Department of Environmental Engineering, Democritus University of Thrace and the International Water Association (IWA) Specialist Group on Strategic Asset Management.

Improve productivity and reduce operative costs

Hot melt adhesives (HMA) are widely used in packaging applications like carton box closing, labels and tapes. Usually packaging cardboard boxes are assembled just before artifact packaging operation. Bonded closures undergo natural constraints of cardboard tending to unfold.

As a consequence, adhesives must be selected to develop higher cohesive strength. Futhermore, automatized packaging manufacture requires, fast development cohesive strength so as to improve productivity.

When packaging are sealed with tapes, high shear is an additional requirement to high cohesive strength.
Some advantages of formulating HMPSA for packaging application using Dynasol SBC's are:

* Wider tackifier resin compatibility.
* Low viscosity development
* Wide temperature range resistance
* Formulation versatility through a wide range of polymers
* Excelent product availavility
* Higher cohesive strength development capability

Key benefits by using Dynasol SBS copolymers in HMPSA for packaging application are set out below:

* Lower viscosity development
* Stronger adhesion
* Productivity improvement by reducing application temperature and set time.
* Operative costs reduction by low temperature operation.
* Superior Adhesive temperature performance.

How's Corrugated Boxes Made?

Corrugated board is manufactured on large high-precision machinery lines called Corrugators running at 500 lineal feet per minute or faster.

The corrugated medium is usually a 26 lb/1000 sq ft (127 g/m^2) paperboard; higher grades are also available. It arrives to the corrugator on large rolls. At the single-facer, it is heated, moistened, and formed into a fluted pattern on geared wheels. This is joined to a flat linerboard with a starch based adhesive to form single face board. At the double-backer, a second flat linerboard is adherred to the other side of the fluted medium to form single wall corrugated board. Linerboards are often kraft paperboard (of various grades) but may be bleached white, mottled white, colored, or preprinted.

Common flute sizes are "A", "B", "C", "E" and "F" or microflute. The letter designation relates to the order that the flutes were invented, not the relative sizes. Flute size refers to the number of flutes per lineal foot. For example, "B" flute is approximately 1/4 inch from the top of one flute to the next, or 50 flutes per foot. "C" Flute is 5/16 inch from flute to flute or 42 flutes per lineal foot. "E" flute is 1/8 inch flute to flute or 90 flutes per lineal foot. Board thickness is an unreliable metric, due to various manufacturing conditions. However, a rough guide is: "C" flute=5/32 inch thick, "B" flute=1/8 inch thick, "E" flute=1/16 inch thick. The most common flute size in corrugated boxes is "C" flute.

Corrugated board is often graded by the basis weights of the linerboards, burst or mullen strength, edge crush test, or flat crush test. TAPPI [[1]] and ASTM test methods for these are standardized.

The choice of corrugated medium, flute size, combining adhesive, and linerboards can be varied to engineer a corrugated board with specific properties to match a wide variety of potential uses. Double and triple-wall corrugated board is also produced for high stacking strength and puncture resistance.


Box Manufacture
Boxes can be formed in the same plant as the corrugator. Alternitively, sheets of corrugated board may be sent to a different manufacturing facility for box fabrication.

The corrugated board is creased or scored to provide controlled bending of the board. Most often, slots are cut to provide flaps on the box. Scoring and slotting can also be accoplished by die-cutting.

The "Flexo Folder Gluer" is a machine that in one single pass prints, cuts, folds, and glues flat sheets of board to convert them to boxes for any application, from storing old family pictures to shipping the biggest of plasma TV sets to the global market. The most advanced of FFG's can run at speeds of up to 26,000 boxes per hour.

The most common box style is the Regular Slotted Container. All flaps are the same length and the major flaps meet in the center of the box.


Box blank showing score lines, slots, and manufacturer's jointThe manufacturer's joint is most often joined with adhesive but may also be taped or stitched. The box is shipped flat (knocked down) to the packager who sets up the box, fills it, and closes it for shipment. Box closure may be by tape, adhesive, staples, strapping, etc.

Cellulosic Ethanol

IN FEBRUARY 2007, the Department of Energy selected six cellulosic ethanol projects to receive up to $385 million in grants. Authorized by the Energy Policy Act of 2005, the funding was part of an effort by the Bush Administration to end the U.S.'s "addiction to oil" and enhance the nation's energy security.

The money was intended to further two of President George W. Bush's goals: to make ethanol out of nonfood biomass, including billions of pounds of agricultural waste, at a cost competitive with gasoline by 2012 and to increase the use of renewable and alternative fuels to 35 billion gal per year by 2017. In all, more than $1.2 billion was to be invested in the six biorefineries.

Two years later, none of the projects has been built, although one is under construction. Two were canceled right out of the gate. Hitches in the plans have turned up in numerous places. From securing feedstock to financing construction to finding a ready market, the experiences of the awardees illustrate that the nascent cellulosic ethanol industry faces several daunting hurdles.

The chosen projects represent technologies including enzyme hydrolysis, acid hydrolysis, and gasification. They were to be located in the Midwest, Southeast, and West and were planning to use feedstocks ranging from corncobs to wood chips. The companies advancing the projects had little in common other than having a plan to turn cellulosic waste into ethanol.

The designers of the DOE program envisioned that the grant money would be invested over four years, with the companies contributing 60% of the plant costs. When fully operational, the six facilities were expected to produce more than 130 million gal of cellulosic ethanol per year.

B.C.T. compression load of a corrugated board box

When a corrugated board box manufacturer tries to develop a new box, one of the design problems he runs into is selecting the correct cross section of the corrugated board. This includes the type of paper and the shape and number of the different layers. The board should meet different design requirements such as the maximum number of stacked boxes. Sometimes the capacity of a box to resist the vertical loads derived from stacking is expressed in terms of the so called "Box Compression Test" (BCT).

From a designer's standpoint, it would be very useful to have a predictive tool that allowed the computation of the BCT number of a box, from the geometry of the box and the cross section of the boards, without the need to make a prototype. Such a tool would speed up the design process and would produce boxes close to the optimum for each particular application. The difficulties in developing a tool like this come from the anisotropic nature of paper, together with the geometrical nonlinearities of an assembly of thin sheets of paper.

The BCT is obtained by simulation of the compression test, with a speed of 10-13 mm/min in the press.

In our methodology, we work at two levels: the global (complete box) level and the local (board) level. The local level analyses the micromechanics of the board and produces macromechanical properties for the study of the box at the global level.

The flowchart describes our methodology. We have created a library with the macromechanical behaviour of different board configurations (different thicknesses and geometries). Using this library, we assign to each box prototype the properties of a corrugated board, so we can easily obtain the BCT number of the prototype.