Additive modified mineral filler

Uprating PVC compounds often involves the careful specification and addition of mineral fillers. This article discusses calcium carbonate, talc and glass fibre, taking into account their size and their shape factor. Rigidity is sensitive to the shape factor of the filler as is the dimensional stability. This study shows that glass fibre is the most efficient filler. Talc is more efficient than calcium carbonates. The impact performance is very sensitive to the particle size. Precipitated calcium carbonate is the only filler to act as an impact modifier. 12 refs. 

The level of measured improvements in toughness attributed to liquid rubber additives is somewhat dependent on the type of test performed as well as the specific SMC recipe. The toughening mechanisms in effect for rubber modified SMC materials have not been well documented. The presence of a low profile additive (LPA), mineral filler, and glass fibers affects the dispersion of the rubbery additive and its effectiveness in toughening the polyester matrix. Interactions between the rubbery additive and each of the typical SMC components have not been well researched. 

Additional data should be obtained with a cationic, and anionic styryl-functional silanes on a filler in a rubber that shows true adhesion (cohesive failure) in peel tests on glass to determine the ultimate effect of adhesion on reinforcement. Data of Tables 1 and 2 suggest that the iso-thiuronium chloride, and the vinylbenzyl functional silanes should be considered generally along with amine and mercaptan-functional silanes in modifying mineral fillers for rubbers. 

Additives such as fillers, oils, and various resins are added into the SBS block polymers to modify the properties and to adjust cost of the compound. The addition of mineral fillers, such as silica, calcium carbonate, and clay, improve tensile strength (at low concentration), resistance to abrasion, and crack growth as well as increases compound viscosity. The addition of oils generally acts as a plasticizer. This leads decreased tensile strength, hardness, and abrasion resistance however, it also increases flowability of the compound. Plasticizers such as naphthenic or paraffinic oils are compatible with polybutadiene, however, not with... 

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene—propylene mbbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance (see Elastomers, ETHYLENE-PROPYLENE rubber). This is done by sequential polymerisation of homopolymer polypropylene and ethylene—propylene mbber in a multistage reactor process or by the extmsion compounding of ethylene—propylene mbber with a homopolymer. Addition of high density polyethylene, by polymerisation or compounding, is sometimes used to reduce stress whitening. In all cases, a superior balance of properties is obtained when the sise of the discrete mbber phase is approximately one micrometer. Examples of these polymers and their properties are shown in Table 2. Mineral fillers, such as talc or calcium carbonate, can be added to polypropylene to increase stiffness and high temperature properties, as shown in Table 3. 

Secondary ingredients in epoxy adhesives include reactive diluents to adjust viscosity mineral fillers to lower cost, adjust viscosity, or modify the coefficient of thermal expansion and fibrous fillers to improve thixotropy and cohesive strength. Epoxy resins are often modified with other resins to enhance certain properties that are necessary for the application. Often these modifications take the form of additions of elastomeric resins to improve toughness or peel strength. 

Polypropylene homopolymer (PP) is a widely used thermoplastic material, despite its brittle behaviour at either low temperature or high loading rates. Improvement in the fi acture toughness of PP can be achieved by either modifying the crystalline structure, or addition of a second phase material [16], The toughening effect and mechanisms of different second phase materials such as stiff fibres, soft rubbery inclusions (EPR, EPDM), and some mineral fillers have been analysed. Recent developments concern the effect of hybrid system consisting of rigid and rubbery inclusions. 

The mineral fillers are a large subclass of inorganic fillers comprised of ground rocks as well as natural, refined, or synthetic minerals. Commodity minerals are relatively inexpensive and are used mostly as additive extenders. Other fillers, so-called specialty minerals, are usually the reinforcing types. There are also inherently small particle size fillers such as talc and surface chemically modified fillers. The inert filler are those added to plastics to alter the properties of a product through physical rather than chemical means. 

Mechanical stren fth tensile, flexural, impact and compressive strength Mechanical properties such as tensile and flexural strength are mainly affected by reinforcements but the addition of these materials (especially glass fiber) may also create a more brittle compound (as with reinforced polyamides), and an elastomeric modifier may often be added to counter this tendency. Elastomeric additives are also widely used to improve impact strength, especially at subzero temperatures. Mineral fillers can improve compressive strength. 

Natural resin paints natural resins (e.g., shellac) or chemical modified natural resins (e.g., colophonium derivates), additions (e.g., methyl cellulose, natural latex, casein), inorganic, organic pigments (mainly natural origin), mineral fillers, additives (organic solvents alcohols, terpenes, oil of turpentine, limonenes), essential oils (eucalyptus oil, oil of rosemary, oil of bergamot) various applications... 

Polyamides are less combustible plastics due to their chemical composition. Unfilled and unmodified PA 6 and PA 66 are rated V-2 according to UL 94, with an oxygen index of about 25 per cent without any added agents. One peculiarity is that glass fibres, mineral fillers, and some additives (such as the impact modifiers) actually enhance the flammability of polyamides they are rated only HB when not flame-retarded. A drawback of polyamides is dripping during the combustion. 

The specific composition of the TPO blend produced depends on the balance of flexural modulus (stiffness) and impact toughness (drop impact and notched Izod) properties needed to meet the target performance specifications. In the formulation of TPO blends, the polypropylene is used normally as the major component, i.e., as the matrix phase, to provide the needed rigidity and thermal stability, while the elastomer dispersion provides the low-temperature impact toughness. A minor amount of a mineral filler such as talc provides additional stiffness and dimensional stability to the TPO. Hence, the levels of elastomer and mineral filler modifiers are carefully adjusted to achieve the desired balance of properties in the TPO. 

The molecular structure and morphology of individual polypropylene resins can be readily modified at the reactor stage via new catalyst systems. Postblends of available resins with various additives promote impact resistance, controlled rheology, thermal stability, and other desirable characteristics of the polymer matrix. The incorporation of chemical coupling agents and mineral-filler or glass-... 

Secondly, we need to consider the position of the modifier. The clay chemistry dictates that conventional onium ions will only become firmly attached to the basal plate surfaces, leaving the edges and other faces untreated. These untreated surfaces will probably have sites amenable to treatment with more conventional additives, such as organo-silanes. Thus, mixed surface treatments may be most effective in covering all active surface sites. Indeed, it has been reported that all common mineral fillers are amphoteric to some extent and therefore have sites for adsorbing both acidic and basic surface treatment additives [26]. 

Boron oxide particles were incorporated to silicone rubber-based mixes containing fumed silica (reinforcing filler) and reference mineral fillers - aluminum hydroxide, wollastonite, calcined kaolin, mica (phlogipite) and surface modified montmorillonite with dimethyl-dihydrogenatedtal-low quaternary ammonium salt. Acidic character of boron oxide, which can disturb the peroxide curing process, was compensated by addition of magnesium oxide. The influence of boron oxide particles on properties of composites was determined and mechanism of their ceramization process studied. 

The role of mineral fillers in plastic compounds is changing. In the past they were used to reduce costs by replacing polymer content by a less expensive material. Now they have a more important role to play since their use can modify processing characteristics or the properties of the finished part. Other uses include their ability to reduce the content of more expensive additives, notably pigments, flame retardants and impact modifiers. Nanomaterials are coming to the fore as potential fillers along with the more traditional options of alumina trihydrate, barium sulfate, calcium carbonate, kaolin and talc. 

PPE-based resins are relatively resistant to burning, and judicious compounding can increase their burn resistance without fee use of halogenated flame retardants. In addition, these blends could be modified wife glass fiber and mineral fillers. Because of low moisture absorption, dimensional stability. 

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