The use of color masterbatch is very simple, it only needs to be mixed with resin particles according to the specified ratio and mixed by hand.
In the operation of the equipment should pay attention to the following issues:
1. The mixing cavity of the injection molding machine or extruder generally has multiple temperature zones, and the temperature near the blanking port should be slightly higher. This is to make the color masterbatch melt quickly after entering the mixing cavity, and the plastic resin should be melted as soon as possible. Mix evenly, which is conducive to the good dispersion of the color masterbatch in the product.
2. Appropriately apply back pressure to the injection molding machine, which can improve the mixing effect of the screw and facilitate the dispersion of pigments. The side effect of applying back pressure is to slow down the injection molding speed.
3. Properly increasing the die temperature of the extruder can increase the brightness of the product.
The basis for determining the proportion of color masterbatch is to obtain a satisfactory coloring effect. As long as the surface tone of the product is uniform and there are no streaks and spots, it can be recognized. The proportion of color masterbatch can be selected as follows:
1:100 Unless the kneading property of the equipment is very good, it is easy to cause uneven pigment dispersion. Generally, it is not recommended for customers to use this ratio.
However, due to price pressure, some customers especially want to use this proportion of color masterbatch. For the sake of customers, they also produce more concentrated color masterbatch with such a low proportion, and the dispersibility of the pigment can generally meet the requirements.
1:50 is used for plastic products with general coloring requirements, and PE and PP color masterbatches are mostly used in this ratio.
1:33–1:25 is used for PO products with higher coloring requirements, lower coloring requirements or general ABS products
1:20 is used for advanced plastic products, including PO, ABS, and can be widely used in injection molding, blow molding, spinning and other processes
1:20 or more is generally used for coloring of advanced cosmetic containers, mostly used in small injection molding machines
When calculating the cost of coloring the masterbatch, the weight of the masterbatch itself should be deducted.
An example is as follows: 2 kg of color masterbatch is added to 100 kg of plastic resin. At this time, the total weight is already 102 kg. Assuming that the resin price is 10 $/kg, and the color masterbatch price is 20 $/kg,
Then the increased cost due to the use of color masterbatch in 102 kg of plastic products is:
2 kg × (20 $/kg – 10 $/kg) = 20 $
Converted to the increased cost of using color masterbatch per 100 kilograms of plastic products:
20 $ / 102 kg × 100 kg = 19.61 $
In most cases this is the case. However, in some cases, coloring with masterbatch is more economical than coloring with toner, because colorists can achieve the coloring effect of higher-priced pigments by combining several lower-priced pigments.
Also consider the following two phenomena:
- In many cases, the pigments used by plastic product manufacturers when using toner for color matching are not the most economical, and due to the lack of familiarity with pigments, repeated experiments in color matching lead to waste of manpower and materials. This problem does not exist with the use of color masterbatches.
- The grades of products colored with color masterbatch are completely different from those colored with toner powder, and their price is also higher. The higher selling price is often higher than the increased cost of using color masterbatch. Instead, mothers can create “profits”. From this point of view, in some cases, coloring with masterbatch is more “economical” than coloring with toner.
Generally, the color masterbatch does not need to be dried and can be used directly. However, except for ABS and NY color masterbatch, they should be dried according to the conventional process.
How long is the shelf life of the masterbatch?
The masterbatch can be stored for a long time.
The pigments in the masterbatch are dispersed and fixed in the carrier resin, in a closed state, and their quality will not change even if they are stored for a long time. but should be stored in a dry, cool environment.
Generally, companies often use several masterbatches to formulate specific colors for small-volume customers. However, without the guidance of the company’s technical personnel, the customer can not use several color masterbatches on their own, let alone mix the color masterbatches produced by different companies, so as to avoid losses caused by incompatibility.
Some pigments have an impact on the flame retardant effect of the product. When used in flame retardant products, it should be pointed out to the color masterbatch manufacturer.
In order to fully display the coloring effect of the masterbatch, the mold must have the corresponding quality, especially the surface must be very smooth.
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The colorant used in the color masterbatch must pay attention to the matching relationship between the colorant, plastic raw materials and additives. The selection points are as follows.
(1) The colorant cannot react with the resin and various additives, and has strong solvent resistance, small migration, and good heat resistance. That is to say, the masterbatch cannot participate in various chemical reactions. For example, carbon black can control the curing reaction of polyester plastic, so carbon black material cannot be added to polyester.
Due to the high molding temperature of plastic products, the color material should not decompose and discolor under the molding heating temperature. Generally, inorganic pigments have better heat resistance, while organic pigments and dyes have poor heat resistance, which should be paid enough attention to when selecting colorants.
(2) The dispersibility and tinting strength of the pigment should be good. When the colorant is not uniformly dispersed, it will affect the appearance of the product; when the colorant has poor tinting strength, the amount of the colorant will increase and the material cost will increase. The dispersibility and tinting strength of the same colorant in different resins are not the same, so this should be paid attention to when selecting the colorant.
The particle size of the pigment is also related to the dispersibility. The smaller the particle size of the pigment, the better the dispersibility and the stronger the tinting strength.
(3) Other properties of colorants should be understood. For example, for plastic products used in food and children’s toys, the colorants are required to be non-toxic; for plastic products used in electrical appliances, colorants with good electrical insulation should be selected; For outdoor plastic products, pigments with good weathering resistance should be selected.
(1) The color masterbatch will absorb moisture after being stored for a period of time, especially PET, ABS, PA, PC, etc., so it should be dried according to the same process as the natural color particle to meet the water content requirements.
(2) The use of color masterbatch to achieve the desired color must be very careful, and color difference and color light changes often occur.
(3) The color masterbatch and other additives will react, so be careful when using it.
(4) Attention should be paid to the selection of the dilution ratio of the masterbatch. If a high dilution ratio is selected, the production cost is lower, but it is also limited by the processing equipment.
- Heat resistance
The temperature resistance of PVC and PE pigments is 160-180 degrees Celsius
The temperature resistance of ABS and PS pigments is 250-280 degrees Celsius
PP, PA, PET pigments can withstand temperature above 280 degrees
Generally, the heat resistance time of the pigment is required to be 4-10 minutes. Generally, the higher the use temperature, the shorter the heat resistance time.
Phthalocyanine blue pigment can withstand temperature of 325 degrees Celsius and change color within 10 minutes
- The migration resistance of migratory pigments refers to: colored plastic products and other solid, liquid, gas and other states, long-term contact with substances or working in a specific environment, may have physical and chemical effects with the above substances, which are manifested as Pigments migrate from within the plastic onto the free surface of the article, or into adjacent plastics or solvents.
Migration Resistance Rating Criteria
Level 1 Level 2 Level 3 Level 4 Level 5
Severe migration, significant migration, slight migration, no migration 3. Most of the inorganic pigments have good light fastness.
- Weather resistance refers to the color stability of pigments under natural conditions.
- Titanium dioxide is divided into: anatase type (A) titanium dioxide rutile type (R) titanium dioxide
Titanium dioxide can improve hiding power, weather resistance, fading resistance, etc.~~~
When the concentration of titanium dioxide is low, the whiteness of PP increases with the increasing speed of its content. When the concentration exceeds 1.5%, the whiteness does not increase. From 1% to 8%, the whiteness increases by 2.8%, which means that beyond a certain concentration After the range, increasing the amount of titanium dioxide does not improve the whiteness. In order to further improve the whiteness, fluorescent whitening agents can be used, and only a small amount of fluorescent whitening agents can significantly improve the tinting strength of titanium dioxide.
Titanium dioxide, alias: titanium dioxide
Titanium dioxide can effectively scatter visible light to plastics to impart whiteness, brightness and opacity.
The concentration of titanium dioxide in PP\ ABS is 1%; in PVC, it is 4%; with the increase of the amount of titanium dioxide, its covering power gradually increases, and tends to balance when the concentration is greater than 8%.
In general, the finer the titanium dioxide particles, the higher the tinting strength and the stronger the covering power.
- Cadmium yellow has strong tinting strength, excellent light resistance and weather resistance, no migration and no bleeding (toxic pigment). This product can be used as a yellow colorant for plastics, with bright color, excellent light resistance, heat resistance, solvent resistance, water resistance and alkali resistance, but not acid resistance, coloring, and hiding power.
- Ultramarine has the function of whitening and toning, it can remove the yellow shade in white products.
The heat resistance grade of the special color masterbatch is generally compatible with the plastic used for the product, and it can be used with confidence under normal temperature. Only in the following cases will cause different degrees of discoloration, one is that the temperature exceeds the normal range, and the other is that the downtime is too long.
What is the difference between granulation coloring and masterbatch coloring?
Masterbatch coloring has the following advantages compared with granulation coloring:
- Coloring and product processing are completed at one time, avoiding the heating process of plastic by granulation and coloring, which is good for protecting the quality of plastic products.
- Minimize the production process of plastic products.
- Can save a lot of power
Will products colored with masterbatches not fade?
There is no absolute non-fading product, and products colored with masterbatch may still fade, but the degree of product is different for different grades, some are more obvious, and some are difficult to detect.
General and Special
Special color masterbatch: It is a color masterbatch manufactured by selecting the same plastic as the carrier according to the plastic species specified by the user for the product. For example, PP color masterbatch and ABS color masterbatch use PP and ABS as carriers respectively.
Universal color masterbatch: A certain resin (often low-melting PE) is also used as a carrier, but it can be applied to the coloring of other resins other than its carrier resin.
Universal color masterbatch is relatively simple and convenient, but has many shortcomings. It is recommended that you choose special color masterbatch.
Why don’t many companies produce universal masterbatches?
The vast majority of formal color masterbatch companies in the world generally do not produce general color masterbatches.
Universal masterbatches have many disadvantages. In fact, the ‘universal’ range of general-purpose color masterbatches is very narrow, and the technical indicators and economic benefits are also poor, which are embodied in:
- Poor predictability of coloring effects
The color masterbatch is used for coloring, and the pigments of the general color masterbatch will show different colors in different plastics, so the predictability of the coloring effect is poor.
- Affect other properties of plastic products
In particular, it affects the strength, and the product is easily deformed and twisted, which is more obvious for engineering plastics.
- Higher cost
In order to be ‘universal’, general-purpose color masterbatches often use pigments with higher heat resistance grades, resulting in waste.
In addition to coloring, can the masterbatch have the functions of flame retardant, brightening, anti-static, anti-oxidation and anti-ultraviolet at the same time?
The color masterbatch can have some of these functions at the same time, if the factory requests this aspect.
Sometimes, although the customer does not ask for it, the masterbatch company will also suggest the user to add some additives according to the needs of the product, such as adding certain additives to the masterbatch, such as brighteners. Of course, this will increase the cost of the product.
The production process requirements of color masterbatch are very strict, and the wet process is generally used. The color masterbatch is made by water phase grinding, phase inversion, water washing, drying and granulation. Only in this way can the product quality be guaranteed.
In addition, while the pigment is being ground, a series of tests should be carried out, such as measuring the fineness of the sanding slurry, measuring the diffusivity of the sanding slurry, measuring the solid content of the sanding slurry, and measuring the fineness of the color paste.
There are four methods for the production process of masterbatch:
(1) Ink method: As the name implies, it is a production method of using ink paste in the production of color masterbatch, that is, through three-roller grinding, a low molecular protective layer is coated on the surface of the pigment. The ground fine paste is mixed with the carrier resin, then plasticized by a two-roll plasticizer (also called a two-roll open mill), and finally granulated by a single-screw or twin-screw extruder.
The process is as follows:
Batching and stirring Coarse color paste Three-roll grinding Fine color paste Two-roll plasticizing Extrusion granulation
(2) Rinse method: The pigment, water and dispersant are sanded to make the pigment particle smaller than 1 μm, and the pigment is transferred into the oil phase by the phase transfer method, and then dried to obtain the color masterbatch. An organic solvent and a corresponding solvent recovery device are required for phase inversion. Its process is as follows:
Rinse of fine color paste Evaporate concentrate drying Add carrier to extrude granulation
(3) Kneading method: After mixing the pigment and the oily carrier, using the lipophilic feature of the pigment, the pigment is washed from the water phase into the oil phase by kneading. At the same time, the surface of the pigment is coated by an oily carrier to stabilize the dispersion of the pigment and prevent the pigment from agglomerating.
(4) Metal soap method: After the pigment is ground, the particle size reaches about 1 μm, and soap liquid is added at a certain temperature, so that the surface layer of each pigment particle is evenly wetted by the soap liquid, forming a layer of saponification liquid. After the salt solution is added, it chemically reacts with the saponified layer on the surface of the pigment to form a protective layer of metal soap (magnesium stearate), so that the finely ground pigment particles will not cause flocculation, and protect certain fine particles.
Widely used in polyethylene, polypropylene, polystyrene, ABS, nylon, PC, PMMA, PET and other resins, producing colorful fibers, clothing, daily plastics, wires and cables, household appliances, agricultural films, automobiles Accessories, health equipment and other products.
- Under sunlight, there are striped pigment bands in the product
This problem needs to be considered from two aspects of plastic physical and mechanical properties and plastic molding process:
1.1 The temperature of the injection molding equipment is not well controlled, and the color masterbatch cannot be fully mixed with the resin after entering the mixing chamber.
1.2 The injection molding machine does not have a certain back pressure, and the mixing effect of the screw is not good.
1.3 The dispersion of the color masterbatch is not good or the resin plasticization is not good.
The process can be adjusted as follows: 1. Slightly increase the temperature of the mixing chamber near the blanking port 2. Apply a certain back pressure to the injection molding machine.
If the above debugging is still not good, it may be the dispersibility or matching problem of the color masterbatch and resin, which should be solved by contacting the color masterbatch manufacturer.
- After using a certain color masterbatch, the product appears to be easier to break
This may be due to poor diffusion and mutual solubility caused by the poor quality of the dispersant or auxiliary agent selected by the manufacturer, which affects the physical and mechanical properties of the product.
- The color is too dark (too light) after being used according to the proportion on the color master manual.
Although this problem is simple, there are many possibilities, specifically:
3.1. The color masterbatch has not been carefully tested, and the pigment is too small or too much
3.2. The measurement is inaccurate during use, and the phenomenon of random measurement by domestic enterprises, especially small and medium-sized enterprises, exists in large numbers
3.3. There is a problem with the matching of color masterbatch and resin. This may be due to improper selection of the color masterbatch carrier, or the manufacturer arbitrarily changing the resin variety
3.4. The temperature of the machine is improper, and the color masterbatch stays in the machine for too long
Processing procedure: firstly check whether the resin variety matches the color masterbatch and whether the measurement is accurate, and secondly adjust the temperature or speed of the machine. If there is still a problem, you should contact the color masterbatch manufacturer.
- For the same color masterbatch, resin and formula, why are the colors of the products injected by different injection molding machines different?
This is often caused by the injection molding machine. Different injection molding machines have different mechanical states due to different manufacturing, use time or maintenance conditions, especially the difference in the degree of closeness between the heating element and the barrel, so that the dispersion state of the color masterbatch in the barrel is also different. phenomenon will appear.
- After changing to another brand of resin, the color of the same color masterbatch and formula has changed. Why?
The density and melt index of different grades of resin will be different, so the performance of the resin will be different, and the compatibility with the color masterbatch will also be different, resulting in color change. Generally speaking, as long as the density and melt index are the same Large, then the color difference will not be too big, you can correct the color by adjusting the amount of color masterbatch.
- Will the pigment migration of the masterbatch during storage affect the quality of the product?
Some masterbatches have a high pigment content (or dye), in which case it is normal for migration to occur. In particular, the color masterbatch added with dyes will cause serious migration. But this does not affect the quality of the product, because after the color masterbatch is injected into the product, the pigment is in a normal color concentration in the product.
- Why some injection products have bad gloss?
There are several possibilities:
7.1. The nozzle temperature of the injection molding machine is too low
7.2. The mold finish of the injection molding machine is not good
7.3. Product molding cycle is too long
7.4. Too much titanium dioxide in the masterbatch
7.5. Poor dispersion of color masterbatch
- After a period of time, some plastic products will fade.
The quality of the basic pigment used by the manufacturer is not good, and the phenomenon of drift occurs.
- Why is ABS masterbatch particularly prone to color differences?
Different brands of ABS produced in various countries have large color differences. Even if the same brand of ABS, there may be color differences in each batch of batches. Of course, color differences will also occur after coloring with color masterbatch. This is caused by the characteristics of ABS, and there is no complete solution in the world. However, this chromatic aberration is generally not serious.
When using ABS masterbatch, users must pay attention to this characteristic of ABS.
Classification by carrier: such as PE masterbatch, PP masterbatch, ABS masterbatch, PVC masterbatch, EVA masterbatch, etc.
Classification by use: such as injection masterbatch, blow molding masterbatch, spinning masterbatch, etc. Each species can be divided into different grades, such as:
- Advanced injection masterbatch
Used in cosmetic packaging boxes, toys, electrical enclosures and other advanced products.
- Ordinary injection masterbatch
For general daily plastic products, industrial containers, etc.
- Advanced blown film masterbatch
For blow molding coloring of ultra-thin products.
- Ordinary blown film masterbatch
It is used for blow molding coloring of general packaging bags and woven bags.
- Spinning masterbatch
It is used for spinning and coloring of textile fibers. The color masterbatch has fine particles, high concentration, strong coloring strength, and good heat resistance and light resistance.
- Low-grade masterbatch
It is used to manufacture low-grade products that do not require high color quality, such as trash cans, low-grade containers, etc.