Filler (materials)
Fillers additives (additives), which increase the volume of a substance mixture, to alter, usually without the essential characteristics thereof. Worldwide, over 53 million tons of fillers are used with a total value of about 16 billion euros for the various application areas such as paper, plastics, elastomers, paints and coatings, adhesives and sealants. To include fillers to the most important raw materials and are available in a variety of everyday items contain.
- 3.1 Food Industry
- 3.2 Pharmacy
- 3.3 Plastics and Elastomers
- 3.4 papermaking
- 3.5 Paints and varnishes
- 3.6 washing powder
- 3.7 Building materials and coating materials
Chemical classification
Fillers may be natural or synthetic organic and inorganic be synthetic or natural.
Organic
Wood flour, pulp, textile fibers, fabric chips
Cork, wheat chaff or sawdust.
Synthetic
Carbon fibers, cellulose derivatives, ground plastics or elastomers.
Inorganic
Rock flour, asbestos, glass fiber
Silicates (clay, talc, mica, kaolin, Neuburg Siliceous Earth ), carbonates / sulfates (chalk, dolomite, barite ) and oxides / hydroxides ( powdered quartz, crystalline silica, Aluminium-/Magnesiumhydroxide well as magnesium, zinc or calcium oxides).
Synthetic
Silicates, oxides, hydroxides, prepared by either precipitation methods ( silica, chalk, aluminum hydroxide and magnesium hydroxide ) or thermal processes ( fumed silica, carbon black, metal oxides); Glass fibers, glass beads and glass breakage.
Physical Properties
In composite materials, which are used in technical applications, particle size, particle shape, particle structure, particle size distribution, size of the specific surface area and surface activity of the filler are decisive factors for the properties of the mixture, its further processing and the properties of the Endwerkstoffes. Changes in the fillers completely different results can be achieved for example by curing of coatings and plastics or after vulcanization of elastomers.
Applications
Food industry
In foods Food additives are used as a filler, which form a part of the volume of foodstuff without contributing significantly to its available energy. Thus, the actual energy content per volume or per mass of food is reduced.
Fillers are therefore used here to reduce the physiological caloric value of a food (eg light products ) and / or to increase the volume of a food (eg, chewing gum). Some additionally act as dietary fiber. Among the most important fillers include mainly water and air ( but not food additives as defined in the relevant regulation represent ), and also:
- Cellulose ( E460)
- Polydextrose ( E 1200 )
Pharmacy
Tablets contain the active substance and excipients except depending on the formulation, fillers, usually lactose, glucose, sucrose, starch, calcium sulfate, or microcrystalline cellulose.
Plastics and Elastomers
In plastics engineering fillers are used to optimize the profile of properties of plastics. The training is done by a compounding. In the foreground of compounding with fillers often focus on optimizing and increasing the stiffness, reduction of shrinkage and improve the surface appearance. Next, a specific increase in the thermal or electrical conductivity is possible.
The finished product of the compounding is divided into two groups, the polymer compound and additive or color masterbatch. For the fabricator of plastic materials, the use of such products is more accurate and cleaner.
A plastic compound is a premix that can be processed in most cases without additive. Additive masterbatches are those products that are filled with chemical substances in order to modify the properties of the plastic, such as lubricants or anti- block, both products which are used in the film industry.
Color masterbatches find its justification in the fact that it is cleaner to use a already finished batch instead of raw pigments as additive. In this case, the pigment prior to use is incorporated in a carrier material which is compatible with the plastic to be colored. The degree of filling of such color batches can reach up to 85 % depending on the nature of the pigments. Of a combi - batch occurs when multiple properties are to be achieved with a batch ( Slip-/Antiblock-Batch ).
In order to clarify the confusing picture of Compound, additive and color masterbatch with a comparison: Compounds can be equated with finished baking mixes that are to be processed directly without further additives. Additives assume the role of yeast or baking powder, color can be the chocolate or cocoa, which are added to a cake mix. Batches are only parts of the compound in terms of the finished mixture.
Fillers important thermoplastic materials are:
- Glass fibers, glass beads and glass breakage
- Mineral fillers such as calcium carbonate and talc
- Carbon fibers ( short fibers )
- Russian
Also in thermoset fillers are often used. They are in this field often the cause of increased demands on the Vergussanlagen used for processing, due to the increasing viscosity of segregation ( separation ) of the phases as well as the abrasive effect of the fillers.
For elastomers, carbon black and inorganic fillers are used. There are in this case the mechanical parameters in the foreground.
Papermaking
In paper making are particularly silicates, usually kaolin, a white china clay is used as filler. Kaolin makes the paper more opaque ( opaque ), white, and increases the density. And the filler gives the paper has a smoother surface, as it fills the voids between the fibers. Paper can contain depends on the species, up to 30% filler.
Carbonates often used as fillers, usually of chalk, but as sulfates such as gypsum, or oxides, for example titanium dioxide. Barium sulfate is used as filler for the production of baryta into consideration, which thereby is remarkably difficult.
Fillers are cheaper than the pulp used with the exception of titanium dioxide. By the use of fillers thus can reduce the manufacturing cost of paper. The addition of fillers has now hardly a significant impact on some mechanical properties of the paper. In particular, the tensile strength is not appreciably reduced, as in modern paper recipes by optimized auxiliaries and sizing a highly reliable connection between pulp and filler is achieved. The fillers but serve to increase the whiteness, the influence of the basis weight and the design of the Papiersaugfähigkeit what is the print quality is of great importance.
Paints and varnishes
Coatings are initially liquid or powder applied to objects and then harden to form a coating material. Fillers are herein always used functionally, to influence the processing properties, the optical appearance and sometimes also the feel of a surface.
As plastics, are also used in the coatings industry, preferably mineral fillers such as calcium carbonate and talc, as well as barium sulfate and aluminum hydroxide used.
Washing powder
Duty detergent contains up to 50% sodium sulfate ( Glauber's salt). It hardly affects the the effect, but serves good flow, sensitivity, solubility, and storability. But sodium sulfate leads to salinization of waters.
Building materials and coating materials
When building materials and related materials, the fillers are summarized under the term aggregate