White masterbatch-specific ultra-dispersant R1800-SK, technical performance analysis

R1800-SK Super Dispersant Main Ingredients: Polyolefin ether polymers, Color: Blue paste, pH Value: 6.8-7 at 70°C, Color shade will deepen with temperature changes, colorless when used in products, Good compatibility with all rubbers and plastics, Lubrication performance is 26 times that of wax, Dispersing performance is 113 times that of wax.

R1800-SK Ultra Dispersant at 33 degrees Celsius

Using R1800-SK super dispersant for surface treatment of titanium dioxide, the optimal process for surface treatment with R1800-SK super dispersant was explored. Suitable surface treatment conditions were found to be: pH=6.8, temperature 70°C, and the dosage of R1800-SK super dispersant being 0.5%. If used in a titanium dioxide factory, it is recommended to dilute with an alcohol solvent to achieve a more uniform distribution of the powder. Using this treatment method, titanium dioxide granulesWith high whiteness, surface gloss, coverage, and processing properties, the material was prepared.

Titanium dioxide is widely used as an inorganic pigment in masterbatches. However, during use, finer pigment particles tend to aggregate together, forming larger particles that affect product quality. Therefore, it cannot be used directly and must be dispersed. The dispersion process of pigments can be divided into three stages: wetting, refinement (dispersing), and stabilization (encapsulation) of the refined particles. Pigment surface treatment is the process of stabilizing the refined particles.particles, where substances such as surfactants, modifiers, and derivatives of the pigment itself are deposited on the surface of the pigment particles.

Using R1800-SK super dispersant to treat titanium dioxide has significantly improved the dispersing properties of titanium dioxide. The optimal amount of super dispersant and the best process conditions (temperature) for treating titanium dioxide with a super dispersant have been determined.

1. Theoretical Analysis

The molecular structure of R1800-SK super dispersant is mainly divided into two parts. One part is the anchoring group -COOH, which adsorbs strongly to the surface of pigments through ionic bonds, hydrogen bonds, and van der Waals forces, preventing the R1800-SK super dispersant from decomposing. The other part is the dissolving chain (dispersant), which directly determines the stability of the pigment in the solvent after dispersion (the coating layer does not dissolve below 70°C, and begins toBelow 70°C, it dissolves, converting into an ionic coupling agent to improve the compatibility between titanium dioxide and resin. Therefore, it is necessary that the solvating chain has a high affinity for the dispersant to ensure effective solvating action. The R1800-SK super dispersant forms a certain thickness of a coating layer on the surface of pigment particles, and the solvating chain is relatively extended within the dispersant. When pigment particles are adsorbed with R1800-SK super dispersantThe repulsive effect of the adsorption layer causes the particles to bounce apart, thereby achieving stable dispersion of the pigment particles in the medium.

In the TiO2 color paste, the surface of the particles is enriched with charges, which easily combine with the anchoring groups (-COOH) of the R1800-SK super dispersant. This forms a strong protective layer on the surface of the titanium dioxide particles. Through the spatial barrier effect of the dissolving chain (hydrocarbon chain) of the R1800-SK super dispersant, the titanium dioxide achieves stable dispersion.

II. Experimental Section

1. Experimental Materials

R1800-SK Ultra Dispersant

R298 Titanium White Powder of Pangang Group

Saudi Arabia's LLDPE218W

2. Main Instruments and Equipment

15L High Mixer, 35 Single Screw Granulator, 30 Extrusion and Film Blowing Machine, Photoelectric Spectrophotometer, Torque Rheometer, Photoelectric Direct Reading Color Meter

3. Experimental Methods

首先，将二氧化钛和R1800-SK超分散剂加入高速搅拌机中。搅拌至温度达到约100°C。然后加入LLDPE218W。当材料充分混合后，将其转移到造粒机中进行造粒处理。

Experimental formula: Titanium dioxide R298 69.5g, R1800-SK 0.5g, LLDPE218W 30g

Process Flow: Carrier Resin = Pigment = High-speed Stirring = Granulation = Extrusion and Film Blowing = Coverage = Whiteness = Ultra-Dispersant

4. Performance Testing

(1) Thin Film Coverage Test

Coverage refers to the ability of a pigment to conceal the underlying color of the object being colored. Masterbatch made from titanium dioxide pretreated with different levels of superdispersants, then blown into a film, has its transmittance measured and converted to a light density value at a standard film thickness of 0.02mm (hereinafter referred to as light density value). The higher the light density value, the greater the coverage.

(2) Colorfastness Test

着色力指的是颜料进行染色的能力。塑料中二氧化钛的着色力可以通过白度来表征。白度越高，二氧化钛的着色力就越大。然后，使用不同的预处理颜料制成的白色母料进行测试，并使用色差计来测量它们的白度（以Tencel白度TW为单位）、亮度（L）、黄色度（YI）以及其他数值。

(3) Distributed Testing

分散性指的是颜料在着色介质中分散的能力。用于表征和定性评估分散性的方法包括使用相位对比显微镜或电子显微镜进行观察，以及拍摄照片。定量方法则涉及测量颗粒大小分布。

(4) Processing Performance Test

The processing rheological properties are one of the important indicators for the application of titanium dioxide in plastics. The torque rheological method can be used to evaluate the processing properties of titanium dioxide.

III. Results and Discussion

（1）Coverage

Coverability is an important performance indicator for white masterbatches. The level of pigment dispersion is the main factor affecting coverability. The more evenly the pigments are dispersed, the smaller the particles, and the higher the light density value; conversely, the lower the light density value.

Different amounts of R1800-SK super dispersant affect the dispersion of titanium dioxide in films (constant pH=6.870℃, changing the super dispersant content by 0.3%-2% to treat the pigment surface). The following figure shows the curve of the film's light density value with the amount of super dispersant.

As can be seen from the above figure, as the amount of R1800-SK super dispersant increases, the light density value gradually increases and reaches a maximum value. However, after the amount further increases, it decreases sharply. When the amount of super dispersant is 1.6%, the light density value of the film is at its maximum, reaching 0.386.

The amount of R1800-SK super dispersant used is related to the specific surface area of the pigment. Initially, as the content of R1800-SK super dispersant increases, more anchoring groups are adsorbed on the surface of the pigment. At 1.6%, saturation is reached, and at this point, the light density is at its maximum. As the amount of R1800-SK super dispersant continues to increase, due to the interactions between the dispersants, a 'bridging flocculation' occurs. Pigment particles flocculateby entanglement with the dissolved chains of the super dispersant, resulting in a decrease in light density.

(2) Colorability

The coloring power of pigments mainly depends on the properties of the pigments themselves, but it is also affected by the dispersion of the pigments. It is primarily characterized by the brightness and whiteness of the sample.

The influence of the dosage of R1800-SK super dispersant on the color development

From the above table, it can be seen that the amount of R1800-SK super dispersant has a significant impact on the whiteness and brightness values, both of which are higher than the corresponding values of the untreated pigments. This indicates that the use of R1800-SK super dispersant improves the dispersibility of titanium dioxide. Yellowness indicates the degree of yellowing of the sample. For masterbatch, the lower the yellowness, the better. According to the data in the table,The yellowness value is the lowest at 1.6% when using R1800-SK super dispersant.

(3) Dispersability

Dispersibility has a significant impact on the application performance of titanium dioxide in plastics.

The image below shows Titanium Dioxide that has undergone surface treatment. The conditions are: R1800-SK super dispersant used at a concentration of 1.6%, pH value of 6.8, and 70°C ethanol concentration of 2%. B represents untreated Titanium Dioxide. It can be seen that A has a more uniform dispersion, with smaller particles of Titanium Dioxide; whereas in B, the particles of Titanium Dioxide have severely aggregated. Therefore, treating Titanium Dioxide with R1800-SK super dispersant is necessary.Significantly improves its dispersibility.

There are two methods for measuring the dispersibility of titanium dioxide: quantitative and qualitative. A相差显微镜 can be used to quantitatively observe the dispersion of pigments.

(4) Rheological Properties Determination

Ultra-dispersants consist of two parts: anchoring groups and dissolving chains. Titanium dioxide treated with ultra-dispersants not only improves its dispersibility and coverage, but also, due to the good compatibility between the dissolving chains and the carrier, it can alter the flow properties of the masterbatch.

Conclusion

Based on the above experimental analysis, we can draw the following conclusions:

(1) The use of R1800-SK super dispersant to treat titanium dioxide significantly improves the dispersing properties of the pigment. Moreover, it does not alter the properties of the pigment; instead, the whiteness and processing performance of the titanium dioxide are also enhanced.

(2) The dosage of R1800-SK super dispersant has an impact on surface treatment. When the dosage of R1800-SK super dispersant is 1.6%, the treatment of titanium dioxide has the best effect.

(3) The surface treatment effect is the best at a temperature of 70℃.