|
Wet Strength
The wet strength of paper and paperboard is a measure of how well the web of fibers holding the paper together can resist a force of rupture when the paper is wet. Wet strength is routinely expressed as the ratio of wet to dry tensile force at break. With combined board such as corrugated fiberboard or with laminations, wet strength also includes the ability to stay intact under humid or wet conditions. Wet strength adhesives are often needed. Mechanism The cellulose fibreweb of paper is mainly held together by hydrogen bonds. These are dependent on physical contact between the fibres and can be broken by wetting of the fibres. The residual strength of a wetted paper can be less than 10% of the original strength. Various techniques, such as refining of the pulp and wet pressing on the paper machine can be used to reduce the strength loss of the paper upon wetting. To improve the wet strength it is common to use chemicals. The use of chemicals can retain as much as 10% ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is drained through a fine mesh leaving the fibre evenly distributed on the surface, it can be pressed and dried. The papermaking process developed in east Asia, probably China, at least as early as 105 Common Era, CE, by the Han Dynasty, Han court eunuch Cai Lun, although the earliest archaeological fragments of paper derive from the 2nd century BCE in China. Although paper was originally made in single sheets by hand, today it is mass-produced on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and Housekeeping, cleaning. It may also be used a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melamine Resin
Melamine resin or melamine formaldehyde (also shortened to melamine) is a resin with melamine rings terminated with multiple hydroxyl groups derived from formaldehyde. This thermosetting plastic material is made from melamine and formaldehyde. In its butylated form, it is dissolved in n-Butanol, ''n''-butanol and xylene. It is then used to cross-link with alkyd, epoxy, Acrylic resin, acrylic, and polyester resins, used in surface coatings. There are many types, varying from very slow to very fast curing. Curing Melamine-formaldehyde can be curing (chemistry), cured by heating, which induces dehydration and crosslinking. The crosslinking can be carried out to a limited degree to give resins. Either the melamine-formaldehyde resins or melamine-formaldehyde "monomer" can be cured by treatment with any of several polyols. Applications Construction material The principal use of melamine resin is as the main constituent of high-pressure laminates, such as Formica (plastic), For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper Chemicals
Paper chemicals designate a group of Chemical substance, chemicals that are used for Papermaking, paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and brightness, or by increasing its strength and resistance to water. The chemicals can be defined on basis of their usage in the process. Chemical usage is not only for imparting properties to paper but to handle the water cycles in the process, conditioning of fabrics, cleaning of equipment and several other applications. Chemicals used in paper manufacturing Pulping Chemical pulping involves dissolving lignin in order to extract the cellulose from the wood fiber. The different processes of chemical pulping include the Kraft process, which uses caustic soda and sodium sulfide and is the most common; alternatively, the use of sulfurous acid is known as the sulfite process, the neutral sulfite semichemical is treated as a third proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper Bag
A paper bag is a bag made of paper, usually kraft paper. Paper bags can be made either with virgin or recycled fibres to meet customers' demands. Paper bags are commonly used as shopping bag, shopping carrier bags and for packaging of some consumer goods. They carry a wide range of products from groceries, glass bottles, clothing, books, toiletries, electronics and various other goods and can also function as means of transport in day-to-day activities. History The first machine to mass-produce paper bags was invented in 1852 by Francis Wolle, a Pennsylvania schoolteacher. Wolle and his brother patented the machine and founded the Union Paper Bag Company. In 1853, James Baldwin, papermaker of Birmingham and Kings Norton in England, was granted a patent for apparatus to make square-bottomed paper bags. Thereafter he used an image of a flat-bottomed bag as his business logo. In 1871, inventor Margaret E. Knight designed a machine that could create flat-bottomed paper bags, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Packaging Board
Liquid packaging board is a multi-ply paperboard with high stiffness, strong wet sizing and a high barrier coating, e.g. plastic. Only virgin paper fibers are used. The barrier coating must hold the liquid and prevent migration of air and flavors through the paperboard. Manufacture A liquid packaging board might be up to five plies and is formed on a multi-ply paper machine with online coating. The most common is to use three plies with a basis weight of about 300 g/m2. The base or middle ply is normally made of pulp from bleached or unbleached chemical pulp, chemi-thermo-mechanical pulp (CTMP) or ''broke'' (waste paper from a paper machine). CTMP gives more bulk and stiffness. The top ply (inside) is made of bleached chemical pulp. The barrier coating depends on the application and might be applied on both sides. When induction welding is employed an aluminum foil layer is used for barrier protection and for heating. The back side of the board is the printing side and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Paper
Filter paper is a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solid particles from liquids or gases. The raw materials are typically different pulp (paper), paper pulps. The pulp may be made from softwood, hardwood, fiber crops, or mineral fibers. Properties Filter paper has various properties. The important parameters are wet strength, porosity, particle Retention rate, retention, volumetric flow rate, compatibility, efficiency and capacity. There are two mechanisms of filtration with paper; volume, and surface. By volume filtration, the particles are caught in the bulk of the filter paper. By surface filtration, the particles are caught on the paper surface. Filter paper is mostly used because of the ability of a small piece of filter paper to absorb a significant volume of liquid. Manufacture The raw materials are different pulp (paper), paper pulps. The pulp may be from softwood, hardwood, fiber crops, mineral fibr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tissue Paper
Tissue paper, or simply tissue, is a lightweight paper or light crêpe paper. Tissue can be made from recycled pulp (paper), paper pulp on a paper machine. Tissue paper is very versatile, and different kinds are made to best serve these purposes, which are hygienic tissue paper, facial tissues, paper towels, as packing material, among other (sometimes creative) uses. The use of tissue paper is common in developed nations, around 21 million tonnes in North America and 6 million in Europe, and is growing due to urbanization. As a result, the industry has often been scrutinized for deforestation. However, more companies are presently using more recycled fibres in tissue paper. Properties The key properties of tissues are absorbency, basis weight, thickness, bulk (specific volume), brightness, stretch, appearance and comfort. Production Tissue paper is produced on a Fourdrinier machine, paper machine that has a single large steam heated drying cylinder (Yankee dryer) fitted with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Film
Plastic film is a thin continuous polymeric material. Thicker plastic material is often called a "sheet". These thin plastic membranes are used to separate areas or volumes, to hold items, to act as barriers, or as printable surfaces. Plastic films are used in a wide variety of applications. These include: packaging, plastic bags, labels, building construction, landscaping, electrical fabrication, photographic film, film stock for movies, video tape, etc. Materials Almost all plastics can be formed into a thin film. Some of the primary ones are: * Polyethylene – The most common plastic film is made of one of the varieties of polyethylene: low-density polyethylene, medium-density polyethylene, high-density polyethylene, or linear low-density polyethylene. * Polypropylene – Polypropylene can be made a cast film, biaxially oriented film (BOPP), or as a uniaxially oriented film. * Polyester – BoPET is a biaxially oriented polyester film. * Nylon – BOPA/BON is a Bia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
