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the most complete stone lacquer questions

作 者:shenghua 关注:578 发表时间:2019-04-25 09:22:13

The most complete stone lacquer question!


1. White with water, Poor water resistance.

Some real stone paints on the market will be obviously white after being washed and soaked by rain, and return to their original state after sunny weather, which is the direct manifestation of poor water resistance of real stone paints.


Reason 1: emulsion quality is low.

Low price emulsions often add excessive surfactants to increase the stability of the emulsions. These surfactants will greatly reduce the water resistance of the emulsion itself.


Reason 2: too low emulsion dosage.

High quality emulsion has a higher price. In order to save costs, manufacturers only add a small proportion of the emulsion, so that after the drying of the stone paint, the film is loose and not dense enough. The water absorption rate of the paint film is relatively large, and the bonding strength is correspondingly reduced. Once the rainy weather occurs for a long time, the rain will permeate the paint film, resulting in the whitening of the stone paint.


Reason 3: Excess Thickener.

Some manufacturers often add a large number of hydroxymethyl cellulose and hydroxyethyl cellulose as thickeners in the manufacture of real stone paint. These substances are water-soluble or hydrophilic. The water resistance of the coating is greatly reduced by leaving subtances in the film after film formation.


Solutions:

  1. Choose high quality emulsion.
    High molecular acrylic polymer with excellent water resistance was selected as film forming material to improve the water resistance of real stone paint from the source.
  2. Increase the proportion of emulsion.
    Increase the proportion of the emulsion, do a lot of comparative testing on the addition of the real stone lacquer, ensure that after the construction of the lacquer, a dense and complete paint film can be obtained to prevent the rain from attacking.
  3. Adjusting the proportion of hydrophilic substances.
    In order to ensure the stability and construction of the product, it is necessary to add hydrophilic substances such as cellulose. The key is to find a precise balance point, which requires repeated experiments.


2.  Serious waste of spraying splash

Some real stone paints will lose sand or even splash around when spraying, and waste about 1/3 when serious. Bentonite can be used to solve this problem.


Reason 1: Improper gradation of gravel.

Natural crushed stone particles in real stone paint can not use uniform size particles, must be mixed with different size particles, if the use of uniform particles and particles with unreasonable collocation, will cause spatter.


Reason 2: Improper construction operation

It may be that the spray gun is too large and the pressure of the spray gun is not properly chosen.


Reason 3: Improper consistency of paint

The improper adjustment of coating consistency will also result in sand drop and spatter during spraying, which will seriously waste materials.


Solutions:

  1. Adjustment of gravel gradation
    Excessive use of small size crushed stone will reduce the surface texture of the paint film. Excessive use of large size crushed stone will easily cause splash and sand drop. Only with a certain gradation ratio can uniformity be achieved.
  2. Adjustment of construction operation.
    If the reason is the spray gun, the caliber and pressure of the spray gun need to be adjusted.
  3. Adjustment of Coating Consistency
    If the cause is the consistency of the paint, then the consistency needs to be adjusted.



3. Real stone varnish discoloration


Reason 1: The effect of basic acid-alkalinity, which is greater than 9, will lead to discoloration phenomenon.


Reason 2: The uneven thickness in the construction process cause discoloration. In addition, too little amount of real stone paint spraying, too thin film will also cause discoloration phenomenon.


Reason 3:  In the production process of real stone paint, the high proportion of cellulose is the direct cause of discoloration.


Solutions:

  1. Strictly control the acidity and alkalinity of the base, and use alkali-resistant sealing primer as the sealing treatment to prevent alkaline substances from precipitating.
  2. Strict implementation of the normal construction dosage, no Jerry work, the normal amount of real stone paint coating is 4.5-5.5kg/square meter.
  3. The content of cellulose as thickener should be controlled in a reasonable proportion.


4. Real stone paint turns yellow 

The yellowing of true stone paint, in short, is the yellowing of color, which affects the beauty.


The main reason: manufacturers used poor acrylic emulsion as binder, decomposed by ultraviolet radiation, and colored matter was released, resulting in yellowing.


Solutions:

 Use high quality emulsion as binder to improve product quality.


5. Softening of paint film

Main reasons: qualified real stone paint film will be very hard, with nails can not be cut. The film is too soft due to improper emulsion selection or low content.


Solution: making stone paint, not selecting the same emulsion as making latex paint, and choosing a composite solution with higher bonding force and lower film forming temperature.


6. Coating problem

Coating cracking:

The reasons are generally cracking of the base course; the base course is not divided into blocks, or the partitioning blocks are too large; the amount of one spray is too large, the paint is too thick, and the dilution is inappropriate; the performance defects of the paint itself are easy to cause cracking of the coating.


Non-uniform coating:

The reason is that the same batch of coatings are not used; when the coatings are stored, there is floating water in the layer or surface layer, and before spraying, they are not fully stirred uniformly, and the viscosity of the coatings is different; the pressure of spraying time and space is unstable; the caliber of the nozzle of the spraying gun changes due to wear or installation errors.


Coating shedding and damage:

The reason is that the moisture content of the base is too high during the coating construction; it has been impacted by external mechanical forces; the construction temperature is too low to cause poor film formation; inappropriate stripping time or inappropriate methods cause paint damage; the bottom of the outer wall is not made of cement footlines; and the matching bottom sealing paint is not used.


Foaming and bulging of coatings:

The reason is that the moisture content of base course is too high during coating construction; the strength of cement mortar and concrete base course is not enough due to insufficient age or low curing temperature, the design strength of mixed mortar base course is low, or the mix ratio is incorrect during construction; the quality of coating is not qualified; no sealed base coating is used; the main coating surface is not completely dried,  paint varnish coating. 


The coating is too soft:

Improper emulsion selection is the main reason for soft coating, and the lack of emulsion is also one of the reasons. The special emulsion for genuine lacquer should be selected. The bonding strength should not be less than 3 kPa, and the minimum film forming temperature should not be below 20 C.



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