1. Basic structure of TPE/TPR paints.

　　The main components of TPE/TPR paints in the local market are: 1) Resin 2) Solvent 3) Toner 4) Additive. Among them, resin is the main component of the paint, its function is to make the pigment bonded to the surface of the plastic parts. Generally speaking, the resin of the sprayed plastic parts and the oil should be roughly the same in chemical class, so as to ensure that the plastic parts and the paint can be well sprayed without causing the paint or ink to fall off. This is actually a matching problem between the rubber and the paint.

　　As for the solvent, it is mainly used to dilute the resin and erode the surface of the rubber part, so that the rubber part has more surface area for bonding. In terms of TPE paint, generally aromatics and ketones are the main ones.

　　As for the off color powder and additives, respectively, to provide color for the paint itself and reduce the occurrence of foaming. 2.

　　2. What is the problem of bad TPE oiling?

　　A. Solvent reason

　　For general hard body general-purpose materials such as ABS and HIPS, the paint will usually be combined with a weaker chemical performance solvent. In order to ensure that the surface of the plastic parts can still be smooth after spraying without losing physical strength.

　　On the other hand, soft-bodied general purpose plastics, such as PVC, are usually combined with a solvent with stronger chemical properties. Since soft plastic parts have a certain degree of deformation and elongation, strong solvents ensure that the paint sticks firmly to the plastic parts, even if the soft plastic parts are deformed, it is not easy to detach them.

　　TPE combines the characteristics of soft and hard rubber into one. If there is a problem when spraying oil, it is often due to a mistake in choosing the solvent, which can lead to burning and degreasing.

　　1. burn glue - mainly occurs in the TPE hardness of more than 70 degrees of the plastic parts, because the solvent used is too strong, in contact with the plastic parts when the surface is seriously corroded, and leave a line of traces, that is, the so-called burn glue occurred.

　　2. Oil loss - It mainly happens to the plastic parts with TPE hardness less than 70 degrees. Because the solvent used is too weak, the paint can not be firmly attached to the surface of the plastic parts. Once the soft plastic parts are deformed, the paint itself cannot follow the shape change, causing the surface layer to be separated, resulting in oil release.

　　B. Mold design

　　If the surface of the product is uneven, such as the face of the doll, it often happens that the glue burns. The reason is that the uneven part usually has solvent accumulation, so the chance of burning glue increases naturally.

　　C. Excessive ingredients of the water outlet material

　　Manufacturers will generally add different proportions of water-jet material into the production. However, the chemical resistance of the rubber parts will be reduced when the solvent that the pure raw material products can withstand is too strong for the products that contain the sprues, so there is a situation of glue burning.

　　D. TPE with PP or PE

　　Some TPEs contain PP or PE to enhance the adhesion performance. However, PP and PE are chemically resistant adhesive materials, so the oil spraying performance of such TPE products is poor (it is said that the surface can be brushed with PP treatment water to facilitate oil spraying).

　　Solution

　　1. choose the right bath. In general, manufacturers are not recommended to prepare their own paint, and should seek help from professional paint suppliers.

　　2. Try to design the material level as flat as possible, such as design limitations, should try to dilute the paint to reduce the impact of burning glue due to the accumulation of solvents.

　　3. arrange the amount of water outlet material to be below 30%. 4.

　　4. if there is a process of oil spraying, should avoid using TPE containing PP and PE ingredients.