• Types and Advantages and Disadvantages of Thickeners in Waterborne Coatings
    Types and Advantages and Disadvantages of Thickeners in Waterborne Coatings

    2017-10-18

    The dosage of paint additives in the paint is little, but can significantly improve the performance of paint and it has become an indispensable part. Thickener is a rheological additive that not only thickens the coating, prevents sagging in construction, but also gives excellent mechanical properties and storage stability. For the lower viscosity of the water-based paint, it is a very important class of additives. Type of waterborne coating thickener A lot of thickener varieties are available on the market currently, mainly inorganic thickeners, cellulose, polyacrylate and associative polyurethane thickener four categories. Inorganic thickener is a kind of gel mineral that can forming thixotropy by water swelling. Mainly including bentonite, attapulgite, aluminum silicate, etc., of which the most commonly used bentonite. Cellulosic thickeners use a long history, many varieties, with methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, was the main stream of thickeners, One of the most commonly used is hydroxyethyl cellulose. Polyacrylate thickeners can be divided into two types: one is water-soluble polyacrylic acid salt; the other is acrylic acid, methacrylic acid homopolymer or copolymer emulsion thickener, this thickener itself is acidic, with alkali or ammonia to pH8-9 in order to achieve thickening effect, also known as acrylic acid swelling thickener. Polyurethane thickener is a newly developed associative thickener in recent years. The characteristics of various types of thickeners Cellulosic thickeners Cellulosic thickeners have high thickening efficiency, especially for the thickening of the aqueous phase; less restrictions on the coating formulation and wide application; the available pH range is large. But it is poor leveling, roller coating when the phenomenon of more splash, poor stability, vulnerable to microbial degradation and other shortcomings. Because of its low viscosity at high shear, high viscosity in static and low shear, so when the coating is completed, the viscosity increases rapidly, can prevent sagging, but on the other hand,it will caused poor leveling. Studies have shown that the relative molecular mass of the thickener increases and the spatter of the latex coating also increase. Cellulose thickeners are prone to splash due to their relatively high molecular weight. And because the cellulose is better hydrophilic, will reduce the paint film water resistance. Polyacrylic acid thickener Polyacrylic acid thickener has strong thickening and good leveling, good biological stability, but sensitive to pH, poor water resistance. Associated polyurethane thickener The association structure like polyurethane thickener will damage under the action of the shear force, the viscosity decreases. When the force loss, viscosity can be restored, to prevent the sagging phenomenon during construction process. And its viscosity recovery has a certain lag, is conducive to coating smooth. The ...

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  • Sealing tape, transparent tape, packaging tape, bopp tape, the production process
    Sealing tape, transparent tape, packaging tape, bopp tape, the production process

    2017-10-09

    All kinds of sealing tape, transparent tape, packaging tape, bopp tape products,regardless of its type and use, it is made up of three parts: the substrate (rarely the substrate), the pressure sensitive adhesive, the release paper or the separation film. The production process of sealing tape, transparent tape, packaging tape, bopp tape: The pressure-sensitive adhesive is coated on the corona and release agent-treated substrate or temporary carrier by various methods. After drying and curing, the release paper is rewound into a roll (or without the need for direct release of the release paper) , And then cut into products of the specified size and packaged.

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  • Application and application of water-based pressure-sensitive adhesive products
    Application and application of water-based pressure-sensitive adhesive products

    2017-09-26

    Water-based pressure sensitive adhesive Typical varieties are: transparent sealing tape, electrical insulation tape, masking tape, surface protection tape, double-sided tape, metal foil tape, pipe anti-corrosion tape, logo tape (printing tape), silicone heat- Conductive tape, shock absorptive tape, medical tape, transfer tape, adhesive labels, stationery adhesive films, advertising adhesive films, notes stickers and medical adhesive tablets, and so on. The application of water-based pressure-sensitive adhesive products according to the needs of sticky objects and bonding environment and the needs of bonding performance to choose a variety of suitable applications of pressure-sensitive adhesive products. Now lists a variety of water-based pressure-sensitive adhesive products application and selection table. Products Substrate thickness Peel force Tensile degree 10*5pa Elongation % Types Performance requirements The main purpose Kraft paper tape Kraft paper 0.16-0.18 300-700 6 8 NR.HM Resistant to high and low temperature Packaging corrugated boxes bopp tape bopp 0.07 320 5 120 ac Resistant to high and low temperature Packaging corrugated boxes Protect tape PVC 0.12 60-175 3.5 200 ac、nr Good weather resistance,Stripped without residue Metal plate, plastic plate protection Masking tape Wrinkled paper 0.23 380 3.5 25 NR Heat-resistant 180 °, bending adhesive

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  • Water-based acrylic emulsion formulations need to be considered(2):The phase structure of the emulsion particles and the film forming aid
    Water-based acrylic emulsion formulations need to be considered(2):The phase structure of the emulsion particles and the film forming aid

    2017-09-20

    The internal structure of the aqueous acrylic emulsion particles will have an impact on several aspects of the water-based paint formulation. the phase structure will first affect the choice and addition of film forming auxiliaries.Different phases have different hydrophilic / lipophilic characteristics,the lipophilicity of film forming additives is also different.For example, two propylene glycol methyl ether (DPM) is higher hydrophilicity, lower lipophilicity than two propylene glycol butyl ether (DPnB).If the outer layer of the aqueous acrylic emulsion particles is a highly lipophilic phase, the addition of DPM not only affects the film formation, but also allows the excess DPM in water to affect the other properties of the water-based paint film. The other effect of phase structure on the formulation of aqueous coatings is the effect on the film quality of water-based paint film.The key to the quality of the film is in the mixing process of the aqueous acrylic emulsion particles,to allow the mixed phases to be intensively mixied and the separation of the phases to be separated.If different phases are required to participate in the fusion, you should choose a mixed film-forming aid to achieve the best results. Many domestic and foreign literatures on water-based acrylic emulsion polymerization, mentioned the core shell and other emulsion particles structure. Such as core shell, half months, multi-core, hollow, and strawberries and other structures have been reported. The description of these structures is helpful to understand the complexity of the structure of the aqueous acrylic emulsion, but the structure of the water-based acrylic emulsion is much more complicated. For example, only a single phase structure of the particles of the emulsion is not present, the particles in the practical aqueous acrylic emulsion are the distribution of various structures, possibly more core shells, possibly more strawberries, etc. Water-based acrylic emulsion manufacturers control the phase structure of the aqueous acrylic emulsion by the choice of monomer, addition order, surfactant Dosage. The phase structure of the aqueous acrylic emulsion is the technical secret of the emulsion manufacturer, and the information is usually not disclosed. However, supplier will provide its acrylic emulsion recommended additives and proportions . Usually different water-based acrylic emulsion will require different combinations of additives

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