Basic knowledge of masterbatch

First, the basic components of the masterbatch

1. Pigments or dyes

It is mainly divided into organic pigments such as phthalocyanine red, sun-resistant red, permanent yellow and inorganic raw materials such as titanium dioxide, carbon black, iron oxide red and so on. 

2. Carrier

The carrier is the matrix of the masterbatche. Special color masterbatches generally choose the same resin as the product resin as the carrier, and the compatibility of the two is the best, but the fluidity of the carrier should also be considered.

3. Dispersant

Promote the pigment to be evenly dispersed and no longer condensed, the melting point of the dispersant should be lower than the resin, have good compatibility with the resin, and have a good affinity with the pigment. The most commonly used dispersants are: polyethylene low molecular weight wax, stearate.

4. Additives

General masterbatches do not contain, customized through the customer's situation, mainly flame retardant, brightening, antibacterial, antistatic, antioxidant and other varieties. 

Second, the common classification of color masterbatches

Masterbatches can be classified in a variety of ways, such as PE masterbatches, PP masterbatches, ABS masterbatches, PVC masterbatches, EVA masterbatches, etc. classified by carrier; Injection masterbatches, blow molding masters, spinning masterbatches, etc. classified by application. It can be specifically divided into different grades, such as advanced injection masterbatches, ordinary injection masterbatches, advanced blown film masterbatches, spinning masterbatches, low-level masterbatches, special masterbatches, universal masterbatches and so on. 

Third, the advantages of masterbatche coloring compared with granulation coloring

The first coloring and product processing is completed at one time, avoiding the heating process of granulation and coloring on the plastic, which is good for protecting the quality of plastic products; The coloring of the second master color makes the production process of plastic products the most simplified; Third masterbatch coloring can save a lot of electrical energy. 

Fourth, the advantages of using color custards

(A) so that the pigment in the product has better dispersion

A masterbatch is a aggregate made by uniformly loading an extraordinarily large amount of pigment into a resin.  During the production of the master of color, the pigment must be refined to improve the dispersion and coloring power of the pigment. The carrier of the special masterbatche is the same as the plastic variety of the product, which has good matching, and the pigment particles can be well dispersed in the plastic after heating and melting. 

(2) It is conducive to maintaining the chemical stability of the pigment:

If the pigment is used directly, due to the direct contact of the pigment with the air during storage and use, the pigment will absorb water, oxidize and other phenomena, and after the masterbatch is made, the quality of the pigment can be made unchanged for a long time because the resin carrier isolates the pigment from the air and moisture.

(3) Ensure the stability of the color of the product:

The masterbatch particles are similar to the resin particles, which is more convenient and accurate in metering, will not adhere to the container when mixing, and the mixing with the resin is also more uniform, so it can ensure the stability of the amount of addition, thereby ensuring the stability of the color of the product.

(4) Protect the health of the operator:

Pigments are generally powdery, easy to fly when added and mixed, and will affect the health of the operator after being inhaled by the human body.

(5) Keep the environment clean and do not stain the utensils:

(6) The process is simple, the color is easy, saving time and raw materials:

Because the pigment is in direct contact with the air during storage and use, moisture absorption, oxidation, agglomeration and other phenomena will occur, and direct use will appear on the surface of the plastic product, the hue is dark, the color is easy to fade, and when mixing, it causes dust, affecting the health of the operator. The masterbatches are mechanically processed in the production process, the pigments are refined, and the pigments and resin carriers and dispersants are fully mixed, so that the pigments are isolated from air and moisture, thereby enhancing the weather resistance of the pigments, improving the dispersion and coloring power of the pigments, and the hue is bright. Because the masterbatches are similar in shape to the resin particles, they are more convenient and accurate in metering, and do not adhere to the container when mixing, thus saving time cleaning the container and machine and the raw materials used in the cleaning machine. 

V. Precautions for using color cumen:

(1) The use of color custards

The use of masterbatches only needs to be mixed with resin particles in the prescribed proportion and mixed by hand. In the operation of the equipment should pay attention to the following problems: the first injection molding machine or extruder mixing chamber generally has a plurality of temperature areas, of which the temperature near the blanking port should be slightly higher, which is to make the masterbatches into the mixing chamber after rapid melting, and plastic resin as soon as possible mixed evenly, so that the master pigment in the product in a good dispersion state. The second is to apply back pressure to the injection molding machine appropriately, which can improve the mixing effect of the screw, which is conducive to the dispersion of pigments, and the side effect of applying back pressure is to slow down the injection molding speed. Third, the die temperature of the extruder is appropriately increased, which can increase the brightness of the product.   

(2) Determination of the proportion of color masterbatches used

The basis for determining the proportion of color masterbatches is to obtain a satisfactory coloring effect. As long as the surface of the product is uniformly colored and there are no stripes and spots, it can be recognized. The use ratio of the masterbatche can be 1:100, unless the mixing of the equipment is very good, it is easy to have uneven pigment dispersion, and it is generally not recommended for customers to use this ratio. However, some customers due to price pressure, especially want to use this proportion of the masterbatches, for the sake of customers, but also more production of such a low proportion of concentrated masterbatches, and the dispersion of pigments can generally meet the requirements. The ratio of 1:50 is used for general plastic products with coloring requirements, and PE and PP masterbatches use this ratio more. The ratio of 1:33--1:25 is used for PO products with higher coloring requirements, lower coloring requirements or general ABS products.  The ratio of 1:20 is used for high-grade plastic products, including PO and ABS, and can be widely used in injection molding, blow molding, spinning and other processes. The ratio of 1:20 or more is generally used for coloring high-grade cosmetic containers, and is more often used for small injection molding machines 

(3) Calculation of the cost of the use of masterbatches

The weight of the masterbatche itself should be deducted when calculating the cost of masterbatche coloring.

(4) The impact of the use of masterbatches on the cost of products

In most cases, the cost of the product will be increased. However, in some cases, the use of masterbatches for coloring is more economical than the use of toner coloring, because the colorist can achieve the coloring effect of higher price pigments by combining several lower-price pigments. In addition, we should also consider the first in many cases, plastic products manufacturers in the use of toner color selection pigment is not the most economical, and because of the lack of familiarity with the pigment, color matching repeated trials, resulting in waste of manpower and materials is very common. The use of color masters does not have this problem; The second product colored with a masterbatche and the product colored with toner are completely different, and its price is also higher, and the higher price is often higher than the increased cost of using the masterbatche, so the masterbatche can create "profits". From this point of view, in some cases, using masterbatches to color is more "economical" than using powder coloring.   

(5) Drying and storage period of masterbatches

The masterbatches generally do not need to be dried and can be used directly, but with the exception of ABS and NY masterbatches, they should be dried according to the conventional process. The masterbatches can be preserved for a long time. The pigment dispersion in the masterbatch is fixed in the carrier resin and is in a closed state, and its quality does not change even after long-term storage. However, it should be stored in a dry, cool environment 

(6) The configuration of a variety of color masterbatches to colors

Several masterbatches can be used to prepare specific colors for customers with small dosages, but in the absence of the guidance of the company's technical personnel, customers cannot use several color masters on their own initiative, and they cannot mix the color masters produced by different companies, so as not to cause incompatibilities and losses.

Sixth, common defects of color masterbatches

(1) Under the sunlight, there are striped pigment bands in the product

This problem needs to be considered from the two aspects of plastic physical mechanical properties and plastic molding process: there may be a color masterbatche that cannot be fully mixed with the resin after entering the mixing chamber. The reason may be that the injection molding machine does not add a certain amount of back pressure, the mixing effect of the screw is not good, and the dispersion of the masterbatche is not good or the resin plasticization is not good. In terms of process, two aspects of debugging can be made, the temperature of the mixing chamber can be slightly increased by the blanking port, and then a certain back pressure can be applied to the injection molding machine. If it is still not good after the above debugging, it may be the dispersion or matching problem of the masterbatche and resin, and the masterbatch manufacturer should be contacted to solve it. 

(2) After using a certain color master, the product appears to be more likely to break

This may be due to poor diffusion misclubility caused by poor quality dispersants or auxiliaries selected by the manufacturer, affecting the physical and mechanical properties of the product.

(3) There will also be differences in color after use according to the proportion of the masterbatche instructions

The reason may be that the masterbatches have not been carefully tested, and there are too few or too many pigments; The measurement is inaccurate when it is used, and the phenomenon of arbitrary measurement by domestic enterprises, especially small and medium-sized enterprises, exists in large quantities; There is a problem with the matching of the masterbatche and the resin, which may be the improper choice of the carrier of the masterbatche, or the manufacturer may change the resin variety at will; The machine temperature is improper, and the masterbatche stays in the machine for too long. 

We can first check whether the resin variety matches the masterbatche, whether the measurement is accurate, and then adjust the machine temperature or speed, if there is still a problem, you should contact the masterbatch manufacturer. 

(4) The color of the products injected by different injection molding machines will be different

This is often caused by injection molding machines. Different injection molding machines due to different manufacturing, use time or maintenance conditions, resulting in differences in mechanical state, especially the difference in the degree of closeness between the heating elements and the barrel, so that the dispersion state of the masterbatche in the barrel is also different, the above phenomenon will appear.

(5) The masterbatches of different grades are different

Different grades of resin its density and melt index will be different, so the performance of the resin will be different, and the compatibility with the masterbatche will also be different, so that the color change occurs, generally speaking, as long as its density and melt index are not much different, then the difference in color will not be too large, you can adjust the amount of masterbatches to compare the color.

(6) The phenomenon of pigment migration of masterbatches during storage will not affect the quality of products

Some masterbatches have high pigment content (or dyes), in which case migration is normal. In particular, the masterbatches of dyes will occur severe migration. However, this does not affect the quality of the product, because after the masterbatche is injected into the product, the pigment is in a normal color concentration in the product.

(7) The reason for the poor gloss of the injected products

The nozzle temperature of the injection molding machine is too low; The mold finish of the injection molding machine is not good; The molding cycle of the product is too long; Too much titanium dioxide contained in the masterbatch; The dispersion of the color cumen is not good. 

(8) AbS color masterbatches are prone to color differences

Different grades of ABS produced in various countries have a large color difference, even if the same grade of ABS, each batch number may also have color differences, and of course there will be color differences after using masterbatches. This is due to the nature of ABS, and there is no complete solution at the international level. However, this color difference is generally not serious. When using ABS masterbatches, users must pay attention to this feature of ABS.