A additive for silicate synthetic resin coatings

China Coatings Online News Information:
coating raw materials non-toxic harmless or even naturalization trend is leading every paint people to the future of a new generation of coatings in the direction of continuous progress.
In fact, as early as thousands of years ago, inorgeable mineral coatings have long appeared in human production activities, is used in human construction and painting products, inorgeable coatings have not been clearly defined, according to people's habits generally refers to the main substation for inorgeable materials of a class of coatings. Here, the meaning of the main substation is that some inorganic substations (e.g. silicone sol) must be added to the preparation of coatings a certain amount of organic substation compound correction to compensate for the lack of performance. From the 1970s, China's building coatings began to develop, China's production of inorganic building coatings, the substrate is mainly silicone sol and silicate solution, and from the paint varieties are mainly two-part potassium silicate exterior paint, the appropriate amount of organic material silicone external wall coatings, inorganic mold-resistant coatings, inorganic insulated thermal coatings, inorganic anti-dew coatings, cement-benzene emulsion external wall coatings and acid-modified sodium glass coatings.
Inorance silicate coating as a large category of inorance paint is widely used in a variety of buildings of the interior and exterior wall decoration, in a variety of cement substrates on the surface layer through its unique petrochemical role, with good adhesion and water resistance, not only that, its excellent fire retardant effect for modern building safety provides a guarantee. In addition to these functional protection, inorgent itself excellent antibacterial properties also bring a lot of convenience to the later application, as we all know, dyeing bacteria is the most headache problem of synthetic resin coating, once the coating bacteria, not only the end of paint products, its coated substrate surface will also appear ugly marks caused by large areas of re-painting, paint manufacturers and product users have brought unnecessary trouble and property damage.
and the theme of "environmental protection" haunts everyone and the paint industry as a whole. It seems that the entire coating industry chain from upstream raw materials to the production of related coating products are out of step with the concept of "creating a better environment, protecting the earth's home", which makes our paint industry often in the spoiler nature or affect the environment such as the situation of the opposite of human social progress
Not overnight can be completed, this is based on the revolutionary transformation of paint resin, pigment system, based on the continuous innovation of raw materials production process, but also based on our paint manufacturers and paint formulators on the paint raw materials bold taste of new, and inormanderable coatings is the key to solve this decisive problem.
There are already many inorganic coating products on the market, such as diatom mud coatings, mineral colored mud and silicate coatings, while inorganic silicate coatings can be divided into sodium silicate, potassium silicate and colloglyfied silicon dioxide, i.e. silicon soluble Glue coatings, from silicate coatings, it has the advantages of most of the above inorglicer coatings, and due to inorristic silicates or phosphate binders themselves in the bonding and water resistance of various deficiencies, as the current more common silicon Acid system coatings, generally inorganic organic composite coating system, but the inorganic silicate and organic synthetic acrylic resin complex will often occur after a relatively obvious incompatible resulting in increased viscosity of the system, poor construction and a series of problems, and Clariant Chemical as early as 8 years ago began to study inorganic silicate coating system, focusing on improving silicate and a variety of synthetic acrylic resin compatible problems, and in recent years to achieve technical breakthroughs, the use of specific additives to improve the long-term stability of the paint.
product name and functioning
Dispersogen SPS and Dispesogen SPV
as stabilizers of the viscosity of silicate coatings, Dispersogen SPS and Dispersogen SPV are effective in preventing post-thickening problems in the coating system, and the reaction type of thickening after coatings is shown in Figure 1.
and normal silicate fully reactive model is described in Figure 2.
This is also when the higher the concentration of silicate in the system, the higher its viscosity, the more easy to tend to glue one of the main reasons, on this basis, we add specific additives, so that this post-thickening reaction early release, reduce the viscosity of the coating in the later storage process to improve the problem, the viscosity of the system faster and more stable to show, in addition, silicate pH stability is also affecting the system The key to viscosity and storage, due to the high pH of the initial silicate, and synthetic acrylic mixture system silicate coating pH will be affected by resins and other raw materials, in the long-term storage will be more prone to pH changes, in addition, some free metal salts such as Ca, Mg, etc. will also affect the stability of the silicate system so that the product thickens or even breaks milk. Therefore, in the formulation design also recommended that our customers can use as little or no free metal ions as possible pigment fillers.
effects and use methods on inororated silicate coating systems
Dispersigen SPS is a dispersant and stabilizer for silicate coatings, which prevents the subsidion and layering of silicate coatings and extends the shelf life of silicate coatings. Dispersigen SPS usage is 0.5-1.5% of the coating quality ratio. Dispersigen SPS is added with silicate, fillers, pigments and coating additives to the coating premix or reaction material, and after the slurry has dispersed, to the emulsion and the remaining water.
Disersogen SPV is a dispersant and stabilizer for silicate coatings that effectively controls the viscosity of silicates. The recommended dosing is 0.3-1.0% of the coating formula quality ratio. Dispersogen SPV can be added in sync with silicate during the formulation thinning phase, stirred and then added to the desired lotion.
the experimental contents and results
the experimental
of a new generation of silicate coatings can be found in Table 1.
do Dispersogen SPS and SPV bring to the coating system?
. Storage stability;
. . excellent viscosity control;
. . small pH changes;
. . . always excellent construction performance with little impact on paint destaturization;
. . easy to be edified and easy to brush;
. excellent leveling helps the surface with excellent performance.
Experimental results analysis
First, from the parameters of the system viscosity changes, it is not difficult to find that after different storage times, addED SPS and SPV silicate coating (red part, the following picture class) still maintain good viscosity stability, but ordinary paint (blue part, the following picture class) its viscosity showed significant curve changes, see Figure 3.
Second, the stability of pH is also to ensure the viscosity stability of the coating system and performance stability factors, after the use of SPS and SPV coating system and did not use the additive coating system comparison experiments, found that the two changes in pH is basically equivalent, the addition of additives did not affect the pH stability of the coating system, see Figure 4.
And in the yield value data with a more obvious impact on the paint construction performance, it is not difficult to find that the product that adds special additives, its yield value is significantly reduced, see Figure 5, and the yield value of the data characteristics and paint construction labor is positively related, which also shows from another angle that its system has relatively excellent construction performance.
denaturation of coatings has always been a sign of the fluid flow of coating products, from the data in Figure 6 can be clearly found that the special agent SPS and SPV on the establishment of a better leveling silicate coating.
, the recommended dosing of potassium silicate in
resin coatings in various applications is shown in Table 2.
Table 2 these data are based on experimental results, it is not clear that its dosing is limited to these ranges of deep-seated reasons, but there is no more than the previous mention of silicate and resin compatibness, ion stability and system pH effects and other issues, because silicate and resin compatible problems can not be chemically measured, while the resin system is more than a thousand kinds, to accurately judge the specific dosing of silicate in a system is indeed a very difficult thing.
Several problems that may be caused by excessive potassium silicate
the reduction of storage stability leads to high viscosity or excessive variation;
. Very obvious increase in tentacles, poor system mobility, affecting the appearance and color of canning;
. Poor system leveling caused by the late construction process is complex, can not carry out large-scale engineering work;
. . because of the high content of potassium silicate and increase the risk of coating powdering;
. . lead to color changes in a variety of different grass-roots more obvious, color between batches difficult to control;
. water resistance in the early system curing process decreased;
. cost pressure increased, large-scale engineering projects will encounter greater cost pressure.
Some of the problems that can occur when synthetic resin content is high
. Increased viscosity of the system;
. . slightly increased tentacles;
. . resulting in slight changes in color at different base levels; and
. . an initial decrease in water resistance.
in the selection of various raw materials, follow the following basic principles
inorganic silicates: potassium silicate, sodium silicate, lithium silicate, or select some pre-stable mixture of these salt solutions.
synthetic resins: acrylic, styrene acrylic, tri-polymer.
Inorient pigment filler: In the above described pigment free polysalt metal ions will have a certain impact on the silicate system, so in silicate coatings on the selection of pigment composition is very important, generally need to pay attention to the following points.
. Alkaline stable inorgic pigment fillers, free metal ions as little as possible;
. pigments as far as possible to avoid the two-price metal Ca, Mg and tricolor metal Al, Fe, because these metal ions have been reported to affect the system and thus directly or indirectly lead to the system after thickening or even glued problems,
So, considering these, in silicate coatings is not to use dolomite.
: The types of additives that can be used in silicate coating systems are as follows.
dispersants: polyphosphates, polyacrylates, phosphates, cyclane hydrocarbons and lilactin;
. Humidifiers: anions, cations, sex ions and non-ion moisturizers;
. Defocusing agents: long-chain fatty alcohols, silicone emulsions and alkanes;
. Stabilizers: functional compounds, polysephonic compounds;
. membrane additives: alkaline stable esters, alkanes and glycols;
- fluidizers: cellulose derivatives (CMC, HEC), jaundol, polyurethane, polypropylene, modified starch, benton or some modified sheet silicate;
.waterproofing agent: alkaline silicate, sioxane Wax emulsions, lithium fatty acids;
. Fungicides: In general, no additional fungicides are required under high and long-term stable alkaline conditions, but adequate amounts of mold-resistant algae agents are required for external walls or humid areas to ensure a certain amount of dry film long-lasting.
Since the final pH of silicate coatings and gypsum systems is ideal at 10.0-10.5, the raw materials used under this pH condition should meet the alkali stability and unnecessary saponification reaction under such high pH conditions.
's performance metrics are as consistent as possible on the second day and after 30 days of coating production:
. has considerable dewatering shrinkage performance;
. . . tank settle stability is consistent;
. . sheared stirring performance;
. viscosity changes as little as possible;
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As we have seen, some silicate synthetic resin coating systems in contact with these coatings generally have a viscosity growth period of nearly a week, during which the viscosity of the coating may vary by 20 or even 30 KU. Generally speaking, the main reason for subsequent thickening is the compatible of silicate and synthetic resin, so in the production of silicate system coatings, it is necessary to carefully select the silicate used, and in synthetic resin and silicate compatible to spend more energy, extend the heat storage time to determine whether the composite system really reached viscosity stability. In general, it is recommended that the coating maintain a pre-cut of 30-90s during the required roil test and wait for the viscosity to eventually stabilize before recording to ensure the accuracy of the measured data before performing a viscosity test of the silicate coating.
In the primer system, try to select some pre-stabilized mixture of these salt solutions, because with these pre-stabilization systems and our silicone surface coated with a better binding, if the primer silicate stability will directly lead to the improvement of tentacle performance.
conclusion
From the current silicate coating system, because potassium silicate has a better substrate attachment and hydration reactive, more is used in silicate coating system, and as a more widely used silicate coating, silicone sol system is more coating Manufacturers and engineers favor, silicone sol system is a silicone sol and inorge silicone mixed with a new type of silicate system, its biggest feature is that it can have a better adhesion to non-mineral substrates and make silicate coating system into a new era of development.
is different from ordinary potassium silicate coatings, which are basically applicable to all substrates, and because of the removing of metal ions in the general silicate, silicone sol can obtain higher system stability and higher additions to the formula, and the particle size of its products is relatively large, can bring a different appearance to the finished product.
Silicone sol and synthetic resin system basically do not have chemical reactions and only the general compatible problem, but to ensure its good stability with synthetic resin system is premised on emulsion and basic coating emulsion selection must have a small impact on the compatible between the two.
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