Almost everyone knows that paper comes from tree. Not every one of us knows that after trees are collected, they must be dried for at least 3 years before they can be used. Woods needed to be cooked under tremendous heat and pressure and lots of chemicals are added to convert them into pulps. The pulp is then washed, and bleached by lots of clean water, and is finally mixed with another ton of clean water to produce paper. Thus paper production is in fact a highly polluted and water consumed industry, not to mention about the chemical and energy wastes along its production cycle.
Paper choosing is very important in order to perfect a job. Properties of printing paper can be specified by its weight, brightness, and opacity.
A. Basis Weight - Weight is generally measured by the size of 500 sheets (a ream) of paper. Another metric is g/m2or gsm, typical printing paper is 80 g/m2. Thus the weight of a single sheet of paper with a size of 1 m2is 80g.
B. Brightness - Brightness refers to the degree of light a sheet reflects in the range of 0 to 100%.
C. Opacity - Opacity refers to the degree of see-through from a scale of 0 to 100. A sheet with high opacity prevents objects from being visible from the opposite side of sheet.
D. Acid Free - Acid free papers have a pH of 7.0, that is, without any acidity in the pulp.
E. pH - pH is a measure of the acidity or alkalinity of the paper. The pH scale has a value of 0 to 14. Normal buffered papers have a pH between 8.5 and 9.5.
Paper coating is a post processing step to improve the surface protection, smoothness and overall appearances of printed papers. It can also prevent the printed ink from scuffing. Coating can be applied to single side, both sides of the paper or even a specific area. Coating quality can be dull, gloss or matt. Coated papers produce better image effects, and have a better reflectivity. Uncoated papers are generally used for desktop publishing.
A. UV Coating - A special liquid coating, normally latex or clay, is applied to the printed paper surface to provide a protective layer. The surface is then bonded and cured with ultraviolet light. UV coating is preferrable than thin-film lamination as it does not easily wrinkle up. Also, production can be at a very high speed as UV cure is almost instantaneous.
B. Spot UV Coating - UV coating is applied to chosen spot surface only. This helps to draw attention or highlighting a particular part of design in the overall presentation.
C. Press coating - There are different types of vanish including gloss, dull and stain vanishing.
D. Aqueous Coating - Aqueous coating is a water-based coating. It is more environmental-friendly than UV coating and more protective than varnish. .
E. Lamination - There are 2 types of lamination - film based or liquid based. Lamination is best for product catalogues, menus etc as it can help to protect against water and perspiration.
D. Blister packs - Blister packs are a specific type of product packaging with a pre-formed or molded plastic (normally EPS or PE foam) heat sealed over a printed paperboard card to reduce the packaging costs. This kind of packaging is most commonly used to hold pharmaceutical products, and this enables the consumers to easily view its contents but discourages those shoplifters to sneak the small items from the blister packs. Meanwhile, details of the product itself can be printed on the paperboard card backing or on the surface.
Carrier bags can be categorized into paper bags, plastic bags, and eco-friendly reusable bags. While paper bags can readily be recycled as aforementioned in 4. without creating too many enviornmental problems. Plastic bags, on the other hand, pose a threat to the environment and can't be readily recycled. Recently has seen a trend to using eco-friendly reusuable bags which are made by cotton or non woven polypropylene. Polypropylene (PP) is the prefect substitution to plastic as it possesses the same characteristics, which is as strong, lightweight and durable, as plastic, it can be easily recyceld by breaking it into other useful things like food containers, carpets, housewares, HDPE, PET etc.
A. Paper Bags - 。Paper bags can be made by different types of paper like kraft paper, laminated paper, crepe paper etc. The load bearing strengths of the paper bags depend on its design and size. Kraft paper and laminated paper bags provide the best strength and are suitable to carry medium weight products like electronic systems, kitchen wares, etc. Non-laminated paper bags are widely used for retailers or shoppers to carry smaller items like daily grocery, clothes, books etc.
Commonly used paper bag handles include paper twisted handle, hook handle, handles without knot, T-end rope handles, plastic handles, tipping rope handles, synthetic rope handles, jude tape handles
B. Plastic Bags - Plastic bags are general made from a polymer, polyethylene. There are altogether 3 types of polyethylene, namely high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethelene (LLDPE). With its light weight and yet strong structure properties, HDPE is commonly used for glocery bags for supermarkets or take away bags for restaurants. LLDPE on the other hand has the property of very light weight and filmlike thickness, it is especially applicable for tear-away bags for grocery or laundry services. Shopping bags made from LLDPE are usually thicker and heavier and are much more durable than common shopping bags. Though plastic bags are recyclable as composite lumber only, they are not readily decomposed under normal condition as dumpings and thus posed a threat to the environment.
It should be noted that if we compare the carbon footprint of the production of a plastic bag with its paper counter part, paper bag consumes 70% less energy and releases 50% less greenhouse gas.
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