White masterbatch has the characteristics of bright color, eye-catching, high coloring intensity, good dispersibility, high concentration, good whiteness, strong hiding power, migration resistance and heat resistance. It is widely used in injection molding, blow molding and drawing Casting Extruding Extrusion Blown Film Foaming Sheets Tubing Pulling Hollow EVA Bottle Blowing Sheets Household Appliances Toys Packaging Materials Wires and Cables Plastic Bags Automotive Construction Materials Packaging Materials Packaging Materials Packaging Materials Packaging Materials Packaging Materials Packaging Materials Packaging Packaging Packaging Packaging Packaging Packaging Packaging Services Packaging Packaging Packaging Services Packaging Services Packaging Materials Packaging, Sports and leisure products, bags, packaging bottles and other plastic products industry.
White masterbatch the main technical indicators
1, migration resistance (grade) '≥ 4'
2, water content (%) '≤ 0.30'8, the total color' ≤ 1.50 '
3, the melting temperature (oC) '125 ~ 200'
4, white masterbatch dispersion: 'colorless spots, stripes'
5, light fastness (grade) '5-8'
6, the appearance of white masterbatch granular, uniform particles, the same color
7, heat resistance (grade) '≥ 4'
In theory, meet the above technical indicators of white masterbatch, the quality is good.
Buy white masterbatch to consider the 10 aspects
1, whiteness
The whiteness of the white masterbatch is mainly represented by the titanium dioxide in the masterbatch. There are many factors affecting the whiteness of the titanium dioxide, including the size, shape and size distribution of the titanium dioxide particles, the type and content of the impurities and the crystal lattice of the titanium dioxide particles Of the defects.In general, due to the chlorination of raw materials, titanium dioxide purity is high and less impurities in the preparation process, so the whiteness of chlorinated titanium dioxide is better than the sulfuric acid method.In the actual white mother market, many Of the white masterbatch producers add titanium dioxide by adding the same ash content of calcium carbonate, barium sulfate, and zinc sulfide. In fact, the whiteness of these inorganic powders is incomparable with that of titanium dioxide.
2, hiding power
Hiding power is also a very important indicator of white masterbatch, hiding means that the strong coloring of the pigment with a small amount of added to get the desired effect, the hiding power of white masterbatch depends on the choice of titanium dioxide Compared with rutile titanium dioxide, anatase titanium dioxide, which has a smaller and more compact unit lattice and a larger refractive index, the hiding power and UV resistance are significantly better than those of anatase, For the same type of rutile titanium dioxide white masterbatch, titanium dioxide particle size is small, the particle size distribution is narrow, in the masterbatch dispersed good hiding power than the titanium dioxide particle size distribution is broad, poor dispersion in the masterbatch performance Good. Similarly, the common calcium carbonate, barium sulfate, zinc sulfide hiding and titanium dioxide is also incomparable.
Table 1 refractive index of different substances
From the above refractive index comparison we can see that the refractive index of the rutile titanium dioxide and the carrier PE resin maximum difference between the best dispersion, hiding power that is the strongest coloring ability.
3, decentralized
Dispersibility of titanium dioxide in plastic applications have an important impact, in general, the more fine titanium dioxide particles, the better the dispersion, the higher the intensity of its tinting strength, and the film needs fine printing, the use of excellent white mother of dispersion Grain of the pattern clarity, level of feeling, better brightness, which is due to the micro-smoothness of the base film is one of the decisive factors in the quality of printed patterns.
4, moisture content
The water content of the white masterbatch also plays an important role on the properties of the masterbatch. Generally, the water content should be controlled below 1500ppm and the requirements should be strictly below 600ppm. In the injection molding process, the raw materials are usually dried before production , And in the film production, the customer bought and premixed with the carrier directly used, if the water content of the masterbatch, a serious direct result in rupture of the membrane, there will be a small bubble in the film, 'crystal point' And other defects, which causes the white masterbatch moisture from the masterbatch selection of raw materials to the process have an impact.
5, smell
Some film manufacturers use white masterbatch to get a weird smell, which is absolutely not allowed in the milk film and food-contact film, mainly due to the titanium dioxide in the masterbatch In the process of treatment, the choice of coating aids is not appropriate or the amount is too large, or masterbatch production process used in the selection of dispersants have problems, can replace the white masterbatch grades.
6, hue selection
Rutile titanium dioxide due to the low reflectivity in the violet region, therefore, the rutile titanium dioxide has a 'yellow' color, 'yellow' shades will give the colored product gives the 'old' feeling, and will make the fine print image bright Degree and level of decline, which is unpopular among many white masterbatch users, but adding a trace amount of fluorescent whitening agent in the titanium dioxide can absorb the UV wavelength of 300-400nm, and converted to a wavelength of 400 -500nm blue fluorescence, so that the white masterbatch was 'blue phase', white masterbatch users according to their needs to consider.
7, liquidity
White masterbatch liquidity can be expressed as the melt index (MI), the value of low flow is poor, the value of high mobility, good fluidity means good processing performance, low torque machine, power consumption is low, the user selection of white masterbatch , In addition to requiring masterbatch has good fluidity, but also pay attention to masterbatch melt fingering with the carrier resin in their own factory products to be suitable, the general principle is that masterbatch MI is higher than the carrier resin.
8, printing heat sealing performance
White film products in most cases require printing and heat sealing, white masterbatch if the addition of calcium carbonate will affect the clarity and vividness of the printed pattern, add incorrect or excessive dispersant masterbatch will affect the heat sealing and Printing performance.
9, light and weather resistance
White masterbatch generally require light fastness of 7-8, weathering reached 4-5, temperature reached 280 degrees, these requirements are mainly depends on the quality of titanium dioxide, to achieve the above conditions, it must be to rutile titanium dioxide .
10, RoHS & FDA
Heavy metal testing and food contact clearance are also an important indicator of white masterbatch because many white films are used in food packaging and FDA food certification is a test that must be passed.
Precautions when using white masterbatch
1, In order to reduce the fiber color difference after the color, white masterbatch should be diluted to control the mixing ratio, not less than 3% to 10% of filament, staple fiber not less than 1% to 3%, monofilament bulked continuous filament Spinning with three-color equipment, white masterbatch must be mixed into the extruder, while increasing the mixing capacity of the melt itself, but also in the extruder section also added mixing device.
2, mixed with white masterbatch Color silk color formula is determined, the white masterbatch evenly dispersed in the polypropylene yarn before spinning is the key to ensuring product quality, there are two specific types of mixed methods. One is the weight and Volume method, in the extruder or the rear of the white masterbatch after melting, with a small extruder into polypropylene melt, uniformity is very good.
3, the choice of white masterbatch, according to the selection of the range of use, polypropylene masterbatch fine denier, coarse denier class, crude denier class white masterbatch color can not be used for fine denier color, color should be considered when spinning Monofilament fiber denier, choose the same level of white masterbatch.
4, the best selection of white masterbatch is the same manufacturer's products, in order to reduce costs should use high-concentration white masterbatch. White masterbatch pigments are high, medium and low points, color should be based on fiber quality requirements , The appropriate choice of different levels of white masterbatch.In order to avoid the light due to pigment, thermal stability caused by differences in the quality of finished fiber variation, color should also choose to meet the fiber quality requirements, with the same light and heat stable white mother Grain color.