how to select right colorant is important for plastic molding

 Plastic molding products often encounter colorant problems

The type of plastic colorant types, its physical form is divided into four categories.

• powdered colorants – Toner
• paste Colorants – Colorants
• liquid colorants
• solid-like coloring agent – masterbatch

Among them, the widely used coloring agent is powdered colorants and solid form. Therefore, the other two kinds of coloring agents in this article will not discuss.

Two characteristics of a colorant variety. Dye coloring the direct use of dye to add the appropriate amount of powdered additives for plastic particles coloring method, also known as dry coloring.

The advantage of good dispersion, low cost, small-batch operations. Because it obviates the other colorants, such as masterbatch, pigment pastes and process of human and material resource consumption,  Thus low cost, buyers and sellers are not subject to limits on the amount. The manufacture of masterbatch can not do 1 ~ 2kg, but the toner according to the needs of any given quality, preparation is very convenient.

Resin dye coloring, compared with another granulation coloring, processing less experience a degradation process. It helps to reduce the aging of the plastic products and increases their service life. But the biggest drawback is that the paint will be flying in the transportation, storage, weighing, mixing, resulting in pollution, seriously affecting the work environment.

Plastic molding part and environment protect

As the requirements of environmental protection, enterprises ISO9000 indicators, toner coloring is more and more restricted. But special coloring, toner directly mixed coloring and some masterbatch coloring no effect. For example, some heat-resistant, afraid of being cut from the pigment powder masterbatch.

Due to its length when exposed to high temperatures, the coloring effect will be obviously weakened by long shear stress in masterbatch processing equipment.

Pearl powder

Re-coloring plastic is made from pearl toning masterbatch, pearl powder is mixed with coloring plastic, pearl effect is weakened by about 10%, plastic molding products are also prone to flow linear scars and seams. We made this masterbatch to take appropriate measures. Minimize masterbatch
heating at processing temperature, time (no twin-screw granulator, but made with single screw granulator, etc).

Dry coloring another user’s headache problem.

The dye used for coloring is difficult to clean the hopper of the extruder under the action of white oil and wetting agent. When refueling is needed, cleaning barrels become a problem for field operators. The materials are time-consuming and expensive, repeated efforts and the use of masterbatch coloring does not have this problem.

In addition, dyeing pigment powder is evenly distributed in the coloring required by the resin. So this is a good dispersion, this conclusion is only applicable to plastic injection molding products. Thick wall products for blowing film, spinning products are another matter.

Toner is generally not pretreated

when mixed alone in the resin, the time from the extrusion outlet feed screw to the outlet is so long. The plasticizing mixing time is so short so that the pigment powder molecules are combined with the coloring pigment molecules-complete integration, there is no guarantee that there will be the phenomenon of maturity.

Due to the manufacturer’s production date, batch number, toner, the same brand of toner there is a certain color. Even if the user insists on using the same formula, it is difficult to achieve the consistency of color injection between batches in the process.

The masterbatch in the production process through intermediate sampling, testing, adjustment to make up for each batch of toner color. Comparatively speaking, the color of the masterbatch is much more reproducible.
Because of the limitations of dyes used in coloring plastics, they are challenged by other colorants. But production costs are relatively low, fixed colors, colors are not quantitative restrictions,

Colorant for small and medium-sized enterprises in developing countries

In the private sector, in order to participate in fierce market competition, the economy uses toner. Of course, masterbatch coloring has its limitations, adding small, plastic products, processing time is short. Limited by the ratio of length to width of the extruder screw.

Mother granular dispersion is often better stained. Once in the manufacturing process, the dyeing cost must be higher than dye coloring. The difference of masterbatch carrier is different from the need of colored resin, and the surface of plastic products often has no dispersion point, pigmentation and pattern. So the use of masterbatch
limited by their compatibility and dispersion. The choice of universal masterbatch and special masterbatch is precisely because masterbatch coloring dye coloring has many advantages. With the development of plastic processing industry.

In particular, many joint ventures and export products have been established to improve the coloring of masterbatch
Ask. It gradually dominates the applicability of masterbatch classification and can be divided into general masterbatch and special masterbatch.

About colorant masterbatch

 special masterbatch

The choice for the same colored resin as a carrier, by adding a high concentration of pigment (dye). The promotional effect of heating, and plasticizing, mixing, extrusion granulation, made specifically for the dye in the resin. It was known as a special masterbatch. Special masterbatch concentration can be high or low, generally, add 1% to 4%.

 Universal masterbatch

Common masterbatch (some call it the “universal masterbatch”) is the main difference from the special masterbatch. Universal masterbatch is also some kind of resin as the carrier. It can be applied in addition to its carrier resin other than resin coloring, the so-called universal masterbatch. The so-called universal masterbatch generally takes the following measures.

Some manufacturing plants simply do not use resin as a carrier, while all of the propylene with high melting point wax as a carrier. At first, a low melting point, the resin of high melt index as a universal masterbatch carrier, such as PE or EVA. The masterbatch pigment powder in the ratio as high as possible, so universal masterbatch must be a high concentration masterbatch used in plastic molding products are generally 1%.

Different media in the masterbatch carrier is very small (fewer additives factors, usually in about 20%), when it is diluted in the proportion of 1%. For the colored resin contained in the plastics resin content: 0.2kg/100 2g/kg universal masterbatch and other types of pigmented resin (affinity). Universal masterbatch also adopted other measures, such as multi-joint the special role of coupling agent, to extend the mixing time, which is conducive to improving the broad applicability of the universal masterbatch.

The principle of masterbatch proper selection

Let us from manufacturing factories, dealers, users, and economic benefits, convenience or not, product effects. Must choose from the manufacturer in the following aspects.

In order to produce a general masterbatch high heat level, it is suitable for a wide range of pigments. The temperature level of pigment powder to a certain extent, for each increase of 10℃~20℃, the cost of pigment increased from 50% to 100%. General-purpose mother for coloring high melting point resins made of high-temperature pigments.

Granules are materials used to LDPE such low melting point resins to increase residual values.

Another example

A few dyes can be applied to ABS、HIPS. Hard plastic coloring, coloring strength, and no migration, low cost. This is used to make it into the masterbatch can not be used in polyethylene products, because it will migrate seriously and the masterbatch will not be able to choose it as a dye. General masterbatch
Used, it should be for other resins.

Masterbatch costing

The use of materials is limited by production costs and will inevitably increase sales. use cost increase, but not absolute. Sometimes for some users, the cost of using a common masterbatch is reduced because of the use of a specific masterbatch ratio of 1:25 and the use of a common masterbatch
Grain 1:100. One kilogram of universal masterbatch can reach 4 kilograms. Special masterbatch, factory production masterbatch processing cost of 5-10 yuan per kilogram (equipment quality, color masterbatch, color masterbatch type, management standards are different). So even if the common masterbatch unit
Sell and reduce the amount converted to resin coloring per ton instead of using a special masterbatch.

Dealers and users tend to welcome universal masterbatch, easy to use is also a factor, can also save thousands of dollars / ton of freight.