【Popularization of Coating Society】Inspection and storage of paint

If various coatings are stored improperly, precipitation, drying and gelation will occur.

For example, when the temperature of the water-based emulsification method is lower than 0°C, it is easy to destroy the emulsified state and cause it to deteriorate and be scrapped.
Therefore, it is necessary to understand the coating view, deterioration identification and inspection, and master the storage and storage methods of the coating.

Normal appearance and inspection types of various coatings and auxiliary materials.
Normal appearance inspection method.
Water-soluble coatings have no turbidity.
They are viscous by twisting and grinding by hand.
After stirring, the pigments are evenly suspended.
There is a normal slurry state such as abnormal smell and flocculation.
It is muddy, can be taken out for a little trial, and the effect is directly observed.
The synthetic resin coating should have no lumps, no agglomeration, no separation, and a uniform state after stirring.
It can be dried and solidified under natural conditions, and there is no moldy state such as agglomeration, agglomeration, and separation.
Can not be improved after mixing, you can take out a little trial and observe the effect directly.
Auxiliary talcum powder: the particles are finer, the color is not very white.
Grind with fingers to have a smooth and delicate feeling.
Wash with water to remove the white powder: the particles are coarser than talcum powder, and the color is better.
Talcum powder also has a smooth and delicate feeling during white twist grinding, but it is not as good as talc powder.
The gypsum powder can be washed off with water: the particles are coarser, and some are off-white.
Lithopone, lead white): the color white has a dazzling sensation, and the particle size is fine and astringent when twisted between the white powder and the gypsum powder.
It is easy to wipe off the commonly used paints and thinners with gasoline.
Normal appearance and inspection types Normal appearance inspection method Varnishes are clear and transparent, with less color and proper consistency.
The lighter the color, the more transparent the better.

Among them, the novolac is light yellow, brown to yellow-brown, transparent oily liquid, and the alkyd varnish is light reddish brown transparent oily liquid.
If there is turbidity, precipitation, thickening, etc.
, the paint has deteriorated.
You can take out a little to try and observe its effect directly .

You can also pour the sample into a clean and dry colorimetric tube and compare it with standard solutions of different turbidity.
After opening the lid, there is no skinning on the surface of the paint (slight skinning is allowed), only a thin layer of oil or thinner, below It is thicker, but it can be fully mixed once it is stirred.

The color meets the requirements, and the viscosity is moderate, such as precipitation, skinning, thickening, thickening, etc.
, indicating changes. After stirring the paint, use a stick to pick up the paint and observe that the color of the paint filaments should fall freely without interruption.
If the retraction is interrupted, it means that the paint will quickly gelatinize and deteriorate the raw lacquer milky white or gray-yellow viscous liquid.
The wooden stick can be drawn into 10-12 cm filaments by dipping a little raw lacquer, and the ends of the thread will be hooked up quickly after being broken.
The raw lacquer is not easy to permeate on the surface of the rough paper.

After brushing, the color changes from white to red, from red to purple, and finally becomes a bright and hard paint film thinner.
A good quality thinner should be a water-white clear and transparent liquid with no impurities, no suspended matter, and no peculiar smell.
;Normal nitro diluents have a banana flavor, alkyd diluents have an aromatic flavor, and amino diluents should have the mild alcohol flavor of butanol.
Normal diluents should have a certain volatilization rate, and there should be no residues after volatilization.
trace.

 You can drop a little diluent on the filter paper, and after a while, you can check whether it is completely volatilized (whether there are residual impurities); mix a small amount of diluent with the corresponding resin or lacquer to observe whether the solubility is good.
Commonly used paint deterioration identification and treatment Method name, phenomenon, cause, treatment method, turbidity, varnish or clear oil is common. Generally, it is slightly turbid and thickened.
The serious ones are improper selection of white paste-like diluent or excessive dosage, room temperature is too low, relative humidity is too large, container is not tightly closed, internal moisture content, lead-based drier dosage When there is too much slight turbidity, add turpentine, butanol or benzene cyclic hydrocarbon solvent, heat to 60-65C with water barrier, control the room temperature at 18-25C, and the relative humidity at 65% +5%.
The viscosity will increase and change.
Thick, in severe cases, the jelly-like paint is too acidic, reacts with basic dyes, over-polymerizes the finished product, overheated, overcooled, container leaks, leaks, and the room temperature is kept at 18~25C.
The paint is heated in water, and alkyd.
Amino paint can be added with 25% butanol in the solvent.
Varnishes: turn black, red, reddish brown.
Paints: the upper and lower colors are inconsistent, and the gold powder and silver powder turn black and turn black.
Varnishes: the solvent hydrolyzes and reacts with the iron container; the paint contains Acidic resin paints: pigments fade, metallic pigments turn green, and the pigment deposits are stored in wooden barrels, porcelain, and glass frit containers: paints are best to be divided into paints and pigments, and they are used now, and a little can be added to the varnish Phosphoric acid precipitation varnishes: the bottom layer has various impurities or insoluble substances, and the upper paint material is intact.
Paints: Under normal circumstances, the sediment can be crushed, and must be crushed in severe cases.
Varnishes: Impurities or insoluble substances in the paint, lead-accelerated The drying agent is too cold or damp during storage, and the solvent is not used properly.
Paints: pigments with high density, too coarse particles, too much body pigments.
Varnishes: filter to remove impurities.
Paints: regularly and repeatedly inverted, fully stirred during use, and agglomerates Then re-grind and mix or use it on unimportant parts.
The container is deformed.
The container bulges and expands.
The temperature inside the container is too high.
The paint becomes gaseous and the temperature is low.
Open the paint bucket.
There is a thin layer on the surface, sometimes Small particles or all gelation phenomenon The container is not tightly closed, the surface of the paint is in contact with the air, and the drier is added too much. The storage time is too long.
Re-filter the paint before use.
After the paint is left, sprinkle the thinner and drier on the paint surface.
Part of the zinc and calcium drier is used to swell and liver: it is hard gelatinous and thick.
Increase or condense into jelly and false thickness: The thick oxide on the surface meets the acidic natural resin coating, the oil and lumber are over polymerized, there are water-soluble pigments in the latex, and the pigment contains salt-containing substances.
Too much dry agent is used, paint There are too many pigments in it, especially when zinc oxide, lithopone, carbon black and other pigments are used once hepaticized.
This kind of coating should not be stored for too long.
It can be restored to normal by adding a small amount of organic acid after mechanical stirring.
Restore the original state, after stopping the stirring, it is still in a false thick shape, but the coating can still be used.
Storage and safety protection Material name Storage method Precautions Oil-based paint, alkyd paint, polyurethane paint, oil-based varnish, polyurethane varnish, oil-based filler, alcohol-soluble hydrogen putty, asphalt put The shelf should be marked with signs.

In order to avoid deterioration due to long storage time, the new material should be placed in the back and the lid should be tightened to prevent volatilization and skinning.

Constant temperature can make the coating viscosity suitable.

 Place heavy containers below to prevent difficulty in handling.

The canned pigments and materials should be placed upside down regularly to prevent precipitation.
Emulsion paint, emulsion varnish, acrylic paint, colorful paint, chalk, dry pigment, plaster of Paris, paste powder, powdered filler, and put it on the shelf with the mark.

The new materials are placed behind the first stored items and cannot be frozen.
Small pieces are placed on a shelf, large pieces are placed on the floor mat, and scattered materials are placed in a covered box to prevent freezing.

Water-based paint has a shelf life and must be used up within the time limit.
Prevent moisture.

Pay attention to the storage period of gypsum and prevent moisture from condensing.
Putting the alcohol-soluble paint remover on the shelf over 15C will cause swelling and cause it to pop out of the container suddenly. Prevent open flame paraffin creosote (1) Put it in an iron bucket with a switch and put it on the bracket (2) Put it in a 5-20 L can with screw mouth, put it in a low place, tighten the lid, and place it in the main building In a separate sealed place, liquid gas, compressed gas, petroleum cellulose paint, cellulose thinner, chlorinated rubber thinner, methylated alcohol, polychloroformate thinner (1) placed outside, to prevent contact with ice, snow and direct sunlight (2) The structure of the special warehouse is as follows: Wall: use brick, stone, concrete or other fireproof materials to build the roof: use fragile materials to help reduce the explosive force Doors and windows: thickness of 50 mm, outward glass: thickness should not be less than 6 mm Wired glass floor: concrete floor, should be inclined, spilled solution should not be left under the container.
Lighting switch: in order not to cause sparks, it should be installed outdoors and stored in accordance with the most flammable liquid and liquefied petroleum gas storage regulations.
Note: These regulations are only applicable to the storage of materials above 50L.
The storage of materials requires the approval of the relevant local inspection department.