paste

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Wallpaper paste

Pastes are adhesives in the form of an aqueous swelling product made from starch or organic cellulose ethers . Mostly it is methyl cellulose . They consist of 2–20% renewable raw materials and 80–98% water . Pastes set physically through evaporation of the water; they are cold-curing and easy to use.

properties

Non-woven wallpaper paste is applied directly to the wall. To ensure that the desired wall area is wetted with wallpaper paste, there are special, initially colored non-woven wallpaper paste. This discoloration is used for job control and disappears after a short time under the influence of the room air.

Paste forms a highly viscous, non-stringy mass even in the smallest concentrations. Due to the wide variety of wallpaper types, the industry offers different types of wallpaper paste, some of which have very different properties. The processing instructions of the wallpaper manufacturer, which are noted in the inlay of the wallpaper roll, are decisive for the selection of the paste .

Since 1953, wallpaper paste made from methyl cellulose and starch has been widely used. Both substances are non-toxic and are often also mixed with resins and other substances that make the application easier and make the wallpaper paste stronger or more durable. Wallpaper pastes, which mainly contain starch, are inexpensive to produce, but have reduced adhesive strength and overall adhesion. Wallpaper pastes without synthetic resin content have hardly any influence on the water vapor diffusion resistance of the wall surface, but they have a low initial adhesion and moisture resistance.

Conditions:

  • An increased initial adhesion is required when gluing very heavy wallpapers. Especially when gluing textile, fleece and vinyl wallpapers, which have a high internal tension that can hardly be relieved by soaking beforehand, the immediate adhesive strength of the paste is important.
  • A water-soluble paste is often desirable, as this can be loosened by soaking it when the wallpaper is removed later. In rooms with very high humidity, however, a waterproof paste should be used. Even if a multiple coat or a coat of thicker layers and aqueous colorants is planned, the paste should not dissolve too quickly. However, problems usually only arise if the substrate is not very absorbent and several layers of paint are applied wet-on-wet, or if the paint builds up an unusually large amount of tension when it sets.

species

In the trade, paste is mainly offered in powder form as normal or special paste:

Normal paste
Many paper wallpapers and waste can be glued with normal paste based on starch or modified cellulose ethers . They are soluble in cold water without lumps and have a high water binding and water retention capacity. Normal paste consists largely of renewable raw materials, but can also contain additives that accelerate the preparation of the paste or protect it from fungal attack.
Pure methyl cellulose without further additives is rarely offered as ready-made paste. It is more stable in storage and more productive, but should be prepared the day before. To make paste from starch, the starch is first mixed with cold water and then - depending on the type of starch - scalded with boiling water or boiled through.
For handicrafts and modeling such as For example, for the production of paper mache , pH-neutral pastes based on pure methyl cellulose are suitable.
Special paste
For heavier wallpapers (vinyl, embossed or woodchip wallpaper), synthetic resins such as PVA and, if necessary, other chemical components such as plasticizers or biocides are added to the paste, since the adhesive strength of the pure cellulose ethers is not sufficient.
Non-woven wallpaper paste
Wallpaper paste for non-woven wallpaper is has a particular consistency, it is set spraying arm, he that as a direct paste for direct application to the wall with a suitable short hair roller. Since non-woven wallpapers do not have to soak, they are laid dry in the paste bed. In order for the wallpaper to hold securely when attached to the wall, the non-woven wallpaper paste should have a high initial tack.
Wallpapering machine paste
Paste designed for the most common paper wallpapers and woodchip, which has been specially adapted for use in pasting machines thanks to its creamy consistency. Nowadays, specially adapted wallpapering equipment glue also enables the bonding of non-woven wallpapers or so-called renovation fleece.

use

  • To stick wallpaper, the surface should have a certain absorbency and the wallpaper should be somewhat water vapor permeable so that the paste can dry off. Steam un translucent wallpaper as metal foil or vinyl wallpaper on low to non-absorbent substrates require special adhesives that harden even when wet.
  • In bookbinding , paste is also used as an adhesive. If a greater adhesive strength is required, also mixed with wood glue .
  • In the manufacture of paper mache , paste is mainly used as a binding agent.
  • In street art , paste is used to attach prefabricated and cut-out works (so-called cutouts) to walls.

Meyers Konversations-Lexikon, 1888:

“Paste (bookbinding paste) - adhesive for bookbinding work, is obtained from wheat starch by mixing it with a little cold water to a pulp and pouring it into hot water in a thin stream while stirring vigorously until it has the right consistency. You shouldn't boil the paste because it will easily come off after drying. The pure paste is processed cold or, if you mix it with a little glue water to increase its adhesive strength, lukewarm. For coarser work, paste is made from rye flour, and if you mix the still hot paste with half the weight of the starch used or the flour turpentine , the paste adheres better, withstands moisture and is particularly suitable for sticking new wallpapers onto old ones . In order to make the paste more durable, one dissolves the 16th part of the weight of the latter alum in the water with which the starch is brewed, or mixes the finished, cold paste with a little creosote or gasoline. To keep insects away from the things made with paste, boil the water with a little aloe , wormwood or coloquins . "

"Starch - When heated with water, the starch swells at 47-57 °, depending on the origin, the layers burst, and at 55-87 ° (potato starch at 62.5 °, wheat starch at 67.5 °), paste is created, whichever has different stiffening properties depending on the type of starch (corn starch "paste" is greater than wheat starch "paste", this is greater than potato starch paste) and is more or less easily decomposed when acidified. "

Brockhaus` Konversationslexikon, 1902-1910:

“Paste”, an adhesive for paper and cardboard, specifically for bookbinding work. The "paste" is prepared by grinding starch (wheat, rice or corn starch) with cold water to a paste that is not too thick and then adding boiling water in a thin stream while stirring rapidly until the "paste" begins to form, what one perceives in the becoming transparent, and finally pouring in the rest of the required water quickly. Cooking the finished mass is disadvantageous and gives a "paste" which easily comes off. The "paste" made from rye flour is more cohesive because of its adhesive content. However, this paste is not white, but gray to gray-brown. To make the "paste" more durable, you dissolve a little alum or a little salicylic acid in the water that is used to form the "paste", or you scald the flour [* 5] with boiling glue water. "

application

Start

Wallpaper paste is mainly available as a powder. For use, this is stirred into a vessel with clean, clear water (not mineral water), also called "make up". Any clean and rustproof container is suitable as a mixing vessel. It is easiest to stir in cylindrical containers. The processing instructions on the packaging indicate the ratio of powder and water to be mixed. It is important to pour the wallpaper paste into the water very quickly, otherwise it can clump. The wallpaper paste must then swell for some time, depending on the type of paste.

Soaking time

The soaking time describes the period of time that the wallpaper paste has to remain on the wallpaper before it is used to soak it. The soaking time differs depending on the thickness and quality of the wallpaper paper, instructions for this are noted in the insert of the wallpaper roll. The soaking time must be about the same for all courses, as different soaking times can cause pattern shifts. As a result of soaking, the wallpaper expands significantly in width and changes its dimensions. Once the wallpaper paste has dried after the wallpaper has been attached to the wall, a firm connection between the wall and the wallpaper is established. Since the wallpaper contracts again during the drying process, what is known as drying tension occurs, which gives the wallpaper a tight and bubble-free fit on the wall. Non- woven wallpapers are not made of paper and remain dimensionally stable even after exposure to moisture. These therefore do not have to soak and the paste can be painted or rolled onto the substrate and the non-woven wallpaper can be rolled dry into the paste bed.

storage

Ready-mixed paste can usually be stored for up to 14 days, depending on the ambient conditions, if it is covered. This does not apply to normal paste. Benzalkonium chloride can be added as a preservative to prevent mold from forming when paste is stored.

Paste stains

Dried-on paste can only be removed from sensitive surfaces with great difficulty, sometimes even impossible, and leaves a noticeable sheen in the backlight. If wallpaper paste gets onto the front of the wallpaper during wallpapering, it can be dabbed off again with a damp cloth and clear water.

Peel off wallpaper

Old wallpaper can be removed from the wall after soaking. Soaking can be made easier by removing the old wallpaper

  • perforated with a spiked roller before or after wetting ,
  • coated with a chemical wallpaper stripper or
  • is treated with a steam generating wallpaper stripper .

Non-woven wallpapers that have been glued with a special non-woven wallpaper paste can be peeled dry from the wall even after years.

history

For centuries, so-called bone glue was used in the painting and wallpapering trade for wallpapering. In 1888, the master painter and decorator Ferdinand Sichel developed the first ready-to-use wallpaper paste based on plant starch and made bone glue superfluous. Because the "sickle wallpaper paste SM" only had to be diluted with hot water and stirred before use. In the early 1920s, Sichel took over the production of the Dr. Friedrich Supf developed cold water-soluble starch paste in dry form, which is also known as swelling starch. In 1953, Henkel brought a new type of wallpaper paste onto the market under the Metylan brand , which consisted of pure methyl cellulose. The white cellulose powder is immediately absorbed by the water, does not clump and forms a homogeneous solution with a strong consistency in a few minutes. Due to the ease of processing, the high adhesive strength as well as the lime and cement resistance, the new wallpaper paste replaced all previous pasting methods. Since 2002, some wallpaper paste has also been available in low-dust granulate form . In 2010, Henkel developed the first wallpaper paste that was stirred into water as a liquid concentrate. This enabled lump-free mixing and quick use.

sustainability

From an ecological, occupational hygiene and health point of view, there are no better adhesives than paste, says Wecobis, an information system for ecological building materials operated by the German Ministry of Construction (BMI) and the Bavarian Chamber of Architects (ByAK). However, the application areas of paste are limited, it is also said.

supporting documents

  1. ↑ WECOBIS ecological building material information system: product group information paste . Accessed April 4, 2020.

See also

literature

  • Hanoverian biographical lexicon
  • Special knowledge: Perfect product solutions in the field of adhesives and sealants. Publishing house Siegfried Rohn. 2009
  • People and brands. 125 years of Henkel 1876-2001

Web links

Wiktionary: Kleister  - explanations of meanings, word origins, synonyms, translations