Wallpaper Manufacturing Industry: Introduction, History, and Process
A Brief Introduction to the Wallpaper Manufacturers Industry
Wallpapers are the new cool in home decoration. Though it has been several decades since wallpapers appeared in the home decoration market, they are gaining immense acceptance by different people with distinct intents around the globe. Typically, a wallpaper is a woven or non-woven backing with decorative printing.
Non-woven wallpapers are called paper wallpapers, while woven wallpapers are known as fabric wallpapers. A wallpaper isn’t mandatory for decorating inner, or even outer, spaces. Although, it is one of the most preferred ways by which a specific atmosphere, color, style, and theme can be added to any kind of enclosed space, commercial or residential.
Because wallpapers used in home and those used in commercial spaces differ in terms of serviceability, quality standards, weight, et cetera, the wallpaper manufacturing industry is divided into two sections: residential-use wallpapers, and commercial wallpapers. Residential-use wallpapers are made from a wide variety of materials. They can be bought pre-pasted or unpasted.
Commercial use wallpapers are divided across several categories, based on backing composition, weight, and coating/laminate thickness. Every commercial-grade wallpaper is required to pass through a number of serviceability tests. Commercial-use wallpapers must have a vinyl surface and pass a rigorous process of physical and visual testing made compulsory by the Chemical Fabrics and Film Association.
Among the four popular methods of wallpaper printing, designers and wallpaper manufacturers choose one that matches the aesthetics requirement as well as fits in the budget.
Earliest wallpapers were used in Europe and date back to the 13th century. At that time, the wallpapers were painted with images of religious icons. Known as domino papers, these wallpapers mostly enhanced the interiors if the rich. However, over the course of next few centuries, wallpapers were hand block-printed and accepted more widely.
By the 16th century, more expensive wallcovering imitating tapestries hung in the homes of nobility gained popularity. Such wallpapers either came with a repeating image or produced a pattern that spanned across several sheets. By the 18th century, Americans started purchasing wallpapers from France and England. By the 19th century, paper strainers in America started producing local wallpapers. In the 20th century, new methods for wallpaper printing starting to develop as the trend spread to all continents.
Recent advances in wallpaper manufacturing include the development of additional printing methods, use of latex and vinyl as coatings or laminates, and new inks and solvents used for wallpaper printing. Ultrawalls independent wallcovering machinery manufacturing company, founded in 1975 provides wallpapers services pan India.
Manufacturing process of wallpapers involves using a wide variety of raw materials. Typically, wallpapers consist of a backing, applied ink, ground coat, and sometimes paste on the backing used for adhering paper to the wall. Non-woven backings are made of ground wood, wood pulp, or wood pulp combined with synthetic materials. Here is a brief summary of various raw materials used in the wallpapers manufacturing process.
a) Woven Backings — Woven backings are made from some sturdy woven textile, such as drill (a heavy woven cotton resembling jean material). The woven backing is thereafter coated and printed. The background color laid on the surface is ground coat.
b) Ground Coats — Most ground coats come with additives that help in enhancing the ease of drapability, handling, and opacity of the paper used in wallpaper. It receives the printed pattern.
c) Coatings/Laminates — In addition to woven backing and ground coat, coatings, or laminates, are also used. They are made of vinyl (polyvinyl chloride) or latex. The primary purpose here is to make the wallpaper more durable and strippable. The wallpaper is then printed with inks. A vehicle is also used to tie the ink with the backing of the wallpaper.
d) Solvents — The drying time and production time of a wallpaper between various color applications is dependent on the type of solvent used by the printer. For doing so, printers come with the capability of choosing from a number of solvents depending on the wallpaper requirements. Water and acetone are the most commonly used solvents.
e) Pastes — Pastes are optional raw materials used in the wallpaper manufacturing process. When used, they are applied drenched to the backing. Pastes are often made of cornstarch or wheat starch. Prepasted wallpapers are required to be soaked once more while adhering to the wall.
The Wallpaper Manufacturing Process
Wallpaper manufacturing is an intricate process, involving various phases. Manufacturing process of wallpapers is described step by step in the following section:
1. Making the Paper
An entire tree is used for producing ground wood sheets of paper. The bark is removed from the tree, and the tree is pressed against a revolving tread. It results in grinding the wood into slurry. This is used for making a ground wood sheet, a relatively low-cost wallpaper backing.
Wood pulp sheets are obtained by debarking a tree and then chipping it into a slurry. Lignin is an element that cements the wood together. It is separated from rest of the wood pulp by means of running the slurry mixture through a pulp mill along with an application of chlorine dioxide and oxygen. Wood pulp sheets are mixed with fibers. For additional texture, synthetic fibers can also be mixed.
A typical roll of paper from the mill is 65 inch or 1.65 m wide and 6,707 m long. It weighs about a ton. Each paper roll is cut into six sub-rolls, each about 21 inch wide and 3,048 m long. This makes it easier for printing into different sizes of wallpapers to match different commercial and residential requirements.
Prior to printing the pattern on the wallpaper, the backing needs to be coated with a ground color. Ground wood sheets are coated with PVC (vinyl). It varies in thickness depending on the strippability and durability of paper under production. Vinyl used might also be laminated to backings for imparting an exceptional serviceability, apt for large commercial spaces.
Any wood pulp sheet can be coated with one or all of the following coatings:
· Kaolin Clay for Drapability
· Latex for ease of Handling and Coloring
· Titanium Dioxide for Opacity
Wallpaper printing techniques are primarily divided into 4 types. All of them have their own sets of advantages. They are:
I. Surface Printing — In surface printing, impregnated metal rollers with a rubber pattern are used. These are mounted on a single machine. Ink is applied to the surface roller. The ink lays in the rubber pattern or hills sitting above the surface of the roller. Ink is then pressed on to the paper by the roller.
II. Gravure Printing — Individual roller is used for printing a single color. Large, full-size gravure-printing machines can hold as much as 12 cylinders, capable of creating the whole pattern. For durability, copper cylinders are laser-etched and chrome-plated. The paper roll under application moves to one copper cylinder. Thereafter, a back roller picks a color and pushes it against an engraved roller. A steel doctor blade pushes against the engraved cylinder, assisting in forcing ink into the etched detail. For enabling the wallpaper to pick up the ink in the valleys, a rubber roller is used. It presses the paper against the cylinder. In the last step, rollers carry the paper away from the cylinder and put it into a dryer.
III. Silk Screen Printing — A pattern to be imprinted on a wallpaper using silk screen printing requires an individual stencil for each color present in the pattern. Stencils of different colors are used from silk mesh screen using a photographic process. First, a photographic negative is made according to the pattern to be imprinted.
This is followed by attachment of a silk screen stretched over a magnesium or wooden frame. The screen is then coated with a light-sensitive emulsion, followed by placing the photographic negative on top of the screen. When the bright light falls on the screen, the emulsion hardens in regions not covered by the photographic negative. It results in the formation of a stencil.
Each screen is placed carefully with a block, guides, etc. This ensures that the pattern is aligned in a regular fashion all over the wallpaper without any breaks or interruptions. Though there is an endless number of colors that can be used in silk screen printing, high costs limit wallpaper suppliers and manufacturers to use only a few colors.
IV. Rotary Printing — Rotary printing combines mechanics of gravure painting with the precision of photographically produced stencils. It starts with wrapping mesh stencils around hollow tubes mounted within a machine. For imparting color, the ink flows continuously through film-wrapped tubes onto the paper. This technique is preferred for its speed, which is about 80 yards of wallpaper per minute.
Upon successful printing of the wallpaper, it is rolled with a wet cornstarch or wheat starch-based coating. Then it is dried thoroughly before packaging.
Residential-use wallpapers are cut down into rolls of 15 yards or 13.71 meters. Commercial-use rolls are packaged in 30, 45 and 60 yards rolls. A run number, printed label, and hanging instructions are placed against each roll before storing them in a warehouse, where they await the final shipment.