Common problems with artificial stone:

Warpage and cracking

Mainly due to the polyester resin and filler, pigment, uneven mixing and the ratio of accelerator, initiator and resin are not correct. In the artificial stone matrix, that is, in a mixture of stirred resin, filler, pigment, etc., the resin should keep the filler in a uniform suspension state until the resin gel. If the filler is poorly suspended in the artificial stone matrix, it is deposited on the bottom of the casting body, which will cause a difference in the distribution of the filler on the upper and lower parts of the casting body. Since there are many upper layers of resin, heat is released during curing shrinkage and shrinkage is large; the lower layer of resin is less, heat release is less, and shrinkage is small, resulting in warpage or cracking of the product.

Artificial stone surface has bubbles, pockmarks

There are three main reasons for this:

1. The moisture content of the filler exceeds the normal target. When the water content of the filler particles is high, a tiny blisters will form around the surface. Since the curing of the resin is an exothermic process, the heat released by it destroys the balance of the outer wrap of the particles, so that the blisters remain in the artificial stone matrix and solidify. Bubbles and pockmarks appear on the surface.

2. Air is brought into the artificial stone matrix during the mixing process.

3. The ratio of the resin to the curing agent and the initiator is improper, and the bubbles remaining in the matrix cannot be discharged in time.

There are usually three ways to exclude:

1. Vibration defoaming method. The use of this method should pay attention to the amplitude, frequency and vibration time of the platform. The amplitude is too large to deposit the filler on the surface of the template, resulting in one resin lean, slow curing, small shrinkage and low exothermic temperature. The other side is cured by resin. Fast, slow shrinkage, high exothermic temperature, prone to warping.

2. Chemical defoaming method. The polymerization inhibitor (known as defoamer) which has a retarding effect on the cross-linking of the resin can prevent the polymerization of the resin in a certain period of time. After a period of time, the resin can be polymerized at a normal speed to obtain time for the effective discharge of the bubbles. The use of this method has little effect on the heat release caused by the curing of the resin. If the amount of the initiator and the accelerator is reduced, although the polymerization of the resin can be delayed, the quality of the artificial stone is affected by the deformation of the heating curve of the resin.

3. Stirring vacuum method. The artificial rock is kept substantially boiling by the stirring negative pressure, which is beneficial to the chemical reaction and the bubbles generated during the stirring process are easily eliminated.

The above three methods, especially the combination of the first method and the third method, are practical, reliable, and have the effect of long-term use of one investment. The second method, although simple, is too expensive for mass production.

Resin requirements for artificial stone

The chemical structure and curing properties of the resin should be considered when selecting the resin.

1. The chemical structure of the resin generally uses an isophthalic acid-propylene glycol type resin. It can meet the requirements of CMI (American Artificial Marble Association) heat shock 500 cycles, steamed with distilled water for 48 hours, the color remains basically unchanged, anti-white flower, anti-foaming performance is better, but the price is more expensive. Ordinary resins cannot be used in the manufacture of artificial stone.

2. Resin Curing Properties: It is required that the resin should have a moderately low shrinkage rate and a high pre-curing strength, that is, green strength, upon curing.

Improve the hardness and luster of artificial stone surfaces

For artificial stone products to have a perfect appearance, post-cure treatment is very important. The so-called post-cure treatment is to keep the artificial stone product at a certain temperature for several hours. In general, the strength of the polyester resin after curing and demoulding only reaches about 50% of the maximum strength, and it takes several weeks or even months to fully cure, and the final curing can make the strength and water resistance of the artificial stone product greatly. increase. The post-curing treatment can overcome the defects such as deformation and cracking, improve the surface water resistance and thermal shock resistance, increase the strength of the matrix resin, and improve the hardness and gloss of the product and prolong the service life. In the case of shortcomings, the post-cure cycle is too long. It is recommended to use the current state-of-the-art artificial stone surface UV coating process to dry and cure instantly.

Since its production, the self-owned brand “Yucci Artificial Stone” has won high praise from many customers for its high quality requirements. It is the best-selling brand artificial stone product of our company!