Discussion on the texture coating of high PVC scraping exterior wall

Abstract:
experiments, the paper analyzes and studies various factors affecting the storage stability and construction properties of high PVC scratch coatings.
key words:
scratch coating; storage stability; construction
Study on high PVC texture paint of scraping for exterior wall
Dai Zhihao, Hu Zhongyuan, Yu Zhanjiang
(Group) Stock Limited, Shanghai 201707) Abstract:
Through, the. research and analysis on the performance of the impact of the various factors for the high PVC texture paint of scraping. Such as, storage stability, application property etc.
Keywords:
texture paint of scraping; storage stability; application property ;
forewordWith the improvement of people's living standards, ordinary flat latex paint has been difficult to meet the requirements of people's external wall decoration effect, real stone paint texture paint is being used more and more. However, due to over-mining, natural color sand less and less, and there are batch stability, color reproducible more and more difficult problems, although artificial sand can meet the demand, but most of the sand dyeing is oily paint wrap, environmental pollution is very large, with the improvement of environmental protection requirements, artificial sand dyeing restrictions more and more strict, in practical application is not a lot. Textured paint due to adjustable color, good reproducible, gradually become mainstream, which is more applied for high PVC scraping external wall texture paint. At present, the common scratching external wall texture coating on the market is high pigment volume concentration (PVC) 78% to 83% texture coating, this paper on the high PVC scratch texture coating more concerned about storage stability, water resistance and construction.
Storage stability refers to the ability of coating products to resist possible problems such as thickening, re-coarseness, flocculation, layering, clotting, and odor production under certain conditions within a certain period of time, and poor storage can seriously affect the construction effect and protection performance of coatings. Water resistance is the paint film after construction, the carrying capacity of water erosion and resilience (mainly water-resistant white recovery), product water resistance is not good, will lead to whitening of the wall flowers, rain marks, and even peeling. Construction, refers to the paint in the construction process to make qualified finished products difficult degree, with the construction cost of high water, construction on the overall cost control plays a vital role. This paper mainly focuses on these three properties to improve the quality of scratched exterior wall texture paint.
1 experimental part1.1 Raw materials
water, dispersants, moisturizers, deblisters, thickeners, fungicides, acrylic emulsions, redstone titanium dioxide, heavy calcium are all commercially available industrial grade.
1.2 experimental base formulaTable 1 Experimental Base Formula
Table1 The Basic Formula
Table 1 Experimental Basic Formula
1.3 Preparation Process Will Dewater, Cellulose, Propylene Glycol, Film-forming Additives, Desiccants, Dispersants, Moisturizers, Desiccants, PH regulators and other additives mixed evenly, then add titanium dioxide and various fillers dispersed to uniform, and then add emulsion, fungicides, thickeners stirred to even;
1.4 technical indicatorsTesting is carried out in accordance with the requirements of JG/T24-2000 Synthetic Resin Emulsion Sand Wall Paint, the results are as follows
Table 2 Technical indicators for scraping exterior wall texture coatings
Table 2 Technical indicators to the high PVC texture paint of scraping for exterior wall
Table 2 Technical indicators for scraping external wall texture coatings
2 Results and discussion 2.1 Effect of emulsion on paint performance plusPre-screening of 2.1.1 lotion
Table 3 Pre-selected formula for lotions
Table 3 Emulsion pre-selection formula
Table 3 Pre-selected formula for emulsion
Each sample is prepared in 2 pieces: one piece is placed at room temperature after 24h, soaked in water 4h, testing the initial water resistance and recovery, and the other piece is placed at 144h, immersion 24h, testing water resistance and recovery.
6 lotions are selected for sale here, and the experimental data are shown in Table 4.
4 Emulsion type has an important effect on paint
Table 4 The performance of waterproof for coatings to emulsion type
Table 4 effects of emulsion types on paint water resistance
Note: Emulsion A for commercial sale low-soap silicon propylene emulsion
Lotion B for pure cerium emulsion
Liquid C, D for cold-flat silicon modified phenyl propylene emulsion
lotion E, F for silicon modified phenyl propylene emulsion (1 worst, 5 best)

screening and performance effects of 2.1.2 emulsions
the emulsions A, E and F were applied to the experimental base formula respectively, and the test performance was seen in Table 5.
5 emulsion type has an important effect on coating
Table 5 The performance of the coatings to emulsion type
The effect of the 5 emulsion types on coating performance
Note: The fluidity test refers to the fluidity of the slurry portion.
from Table 4 author can be seen: emulsion E than emulsion F in the basic formula, slightly stronger tentacles, formula system yield value is high, not easy to produce floating color, flowering, easy to construct. Emulsion A is higher than emulsion E price, water resistance is slightly worse, cost-effective, here the author chooses emulsion E (silicon modified phenyl propylene emulsion) as the final choice of emulsion.
effect of the amount of 2.1.3 emulsion on coatingWith the increasing amount of emulsion added, PVC continues to decrease, gradually approaching CPVC, and then lower than CPVC. In the basic formula, only adjust the amount of emulsion added, the effect on coating performance can be seen in Table 6.
6 emulsion addition has an effect on coating
Table 6 The performance of the coatings to emulsion addition
Table 6 emulsion addition effect on paint performance
From Table 6, the author sees that with the increase of emulsion, the formula PVC is decreasing, when the PVC is lower than CPVVC, the bonding strength has been rising, more than CPVV began to decline. When PVC near CPVVC when the bond strength is the highest, but also very easy to cause cracking of the paint film, water resistance will also be dragged down; Although the emulsion added 24% or more can meet the requirements, but the cost is too high, low cost-effective, so in the formulation system, PVC in 78%-83% of the time, performance can meet the actual needs, cost-effective.
2.2 thickening system on the performance of coatings
Commonly used thickeners are: cellulose, natural modified clay thickeners, synthetic nano-scale Han de-soil thickeners, alkali-soluble expansion thickeners, hydrophobic alkali-soluble compounding thickeners, polyurethane-type thickeners and polyether-type thickeners. Due to the construction needs, the author needs fiber as the main thickener. Alkaline swelling thickeners are not selected here due to poor water resistance.
2.2.1 Cellulose addition on the performance of the coating
With the increase of cellulose addition, paint film water absorption rate increased, water resistance decreased, opening hours increased, the more obvious the sticky knife, batch scraping first rose and then decreased. The effect of cellulose addition on coating performance can be found in Table 7.
addition of table 7 cellulose has a significant impact on coating
Table 7 The performance of the coatings to add to the cellulose
Table 7 cellulose addition on the paint performance
Here the author found that when the amount of cellulose added is 0.7, the overall performance of the best performance, the author determined the amount of cellulose addition to 0.7.
selection of 2.2.2 clay thickeners isThe author knows that the use of clay thickeners, due to activation can form a stable mesh or card house structure, improve the suspension of the paint, tentacles, can effectively improve the stability of the paint storage, scraping and smoothness. However, these thickeners are complex in structure and vary greatly in performance, so they need to be pre-selected. The experimental method is: at low speed stirring, take 5-7 thickeners added to a container containing 93-95 servings of water, disperse for 3-5 minutes, turn to high speed until uniform, see if it is pulpy, yes, take the appropriate amount of samples into the glass bottle sealed, at room temperature for 1 month, open to see if there is no water, layering phenomenon. No water, no layering for good clay thickeners.
2.2.2 different thickening systems have a significant impact on coating Here in order to facilitate the experiment, clay thickener author selected more excellent performance of synthetic nano-scale Han de-earth thickener. Table 8 shows the effects of different thickening systems on coating performance.
8 The effect of different thickening systems on coating performance
Table 8 The performance of the coatings to different thickening system
Table 8 Effects of different thickening systems on coating performance
As can be seen from the above, in the case of the addition of 0.7 xenon cellulose, the separate use of hydrophobic base dissolved coplate thickening Agent, storage in the slurry viscosity has been rising, poor stability, construction is also prone to produce slight flowering, the use of polyurethane thickeners alone, storage in the slurry viscosity slightly decreased, good stability, storage stability is slightly worse, construction is also prone to produce slight flowering.
After the use of 1% synthetic nanoscale Han deuterial thickener in the formulation, the use of other thickeners decreased significantly, storage stability and construction improved significantly, the viscosity of the slurry in storage was small or basically unchanged, thickener formulations 2, 4 and 5 can meet the requirements, of which thickener formulation 5 is the best.
effects of 2.3 dispersants and wetting agents on coating Texture coating on dispersants, wetting agents do not have too many requirements, commonly used polyacrylic salts can be, whether hydrophobic or hydrophobic, but on the texture paint water resistance has an impact, here the author chooses more hydrophobic ammonium salt dispersants, wetting agent here the author did not choose , because in terms of storage, color display has been able to meet the actual needs, because here the author used synthetic nano-scale bento thickeners, greatly improve the system of hydro-water, oil-related balance, reduce the entire formula system dispersion wetting and thickening system matching difficulty, so as to achieve a better decorative effect.
effect of 2.4 deboulants on coating In the coating, in order to reduce the production of coatings and construction process foam production and foam left traces, the formation of a beautiful coating film and the addition of appropriate defrosting agent. Table 8 shows the effect of deboulant use on paint performance.
effect of the use of desiccants on coating performance is
Table 9 The effect of the use of the coatings to the addition of defoaming agents
Table 9 defoaming agents on coating performance
As can be seen from the author, the right amount of microfoam helps to improve construction.
of 2.5 sands has an important effect on coating In textured coatings, the grade distribution of sand is very important, reasonable grade distribution can reduce the clearance rate, improve the adhesion strength of the coating, water resistance and so on. Similarly, the type of sand has an effect on the performance of the coating. Table 9 shows the effect of the type of sand on paint performance.
the type of sand in Table 10 has a significant impact on
Table 10 The performance of the coatings to sand type
Table 10 sand type of the effect on paint performance
From the author can see that the use of rounded sand than ordinary sand construction is obviously better. The amount of coating of the coating is related to the maximum number of sands used and the maximum number of sands, the larger the number of items, the smaller the sand, the higher the amount of coating. This is because, at the time of construction, the thickness of the coating film is close to the maximum particle size of the sand, the smaller the maximum particle size of the sand, the higher the amount of coating. More often, however, the size of the sand is determined by actual demand.
the total amount of sand and pigment is generally 60%-75% added to the amount of sand, the more the total amount, the greater the amount of coating;