Guide to the use of water-based plastic paint oil repellent: scientific operation improves coating effect

In the field of plastic product coating, water-based plastic paint oil repellent is a key auxiliary agent to solve problems such as paint film shrinkage and oil spots. However, only by mastering the correct method of use can its performance advantages be fully utilized to ensure the quality of coating. Next, this article will introduce the whole process of using water-based plastic paint oil repellent in detail.

1. Preparation before use

I. Understand the characteristics of the coating system and substrate

Before using the oil repellent, it is necessary to conduct a comprehensive evaluation of the coating system of the water-based plastic paint. Different types of water-based plastic paints, such as acrylates, polyurethanes, etc., have different compositions and properties, and their adaptability to different types of oil repellents is also different. For example, acrylate water-based plastic paints have good compatibility with non-ionic surfactant-type oil repellents, while polyurethane water-based plastic paints may be more suitable for fluorine-modified polysiloxane-type oil repellents.

At the same time, it is necessary to fully understand the characteristics of the plastic substrate, including the type of material (such as ABS, PP, PVC, etc.), surface roughness, whether it has been pre-treated (such as grinding, cleaning), and whether there is oil stains, release agent residues, etc. Plastic substrates of different materials have different surface tensions and adsorption properties. The type and degree of oil stains and release agent residues will also affect the selection and use of oil repellents.

II. Choose the right type of oil repellent

It is very important to choose the right type of oil repellent according to the coating system and substrate characteristics. At present, the common types of oil repellents on the market include non-silicon modified polymer type, non-ionic surfactant type and fluorine-modified polysiloxane type.

Non-silicon modified polymer oil repellent: It has good oil resistance and compatibility, suitable for coating scenes with high requirements for recoating, and can effectively solve the paint film problem caused by oil stains on the substrate, but it may hydrolyze under acidic or alkaline conditions. When using it, pay attention to adjusting the pH value of the system.

Nonionic surfactant type oil repellent: It has both defoaming and wetting functions. In water-based industrial coatings, water-based plastic paints and other systems, it can improve the oil resistance of the coating, reduce the cleanliness requirements of the substrate, and has good solubility in water-based systems.

Fluoro-modified polysiloxane type oil repellent: It has excellent surface tension reduction performance, can provide rapid spreading and wettability, effectively eliminate surface defects such as orange peel and shrinkage, and is often used for coating products with high requirements for coating surface quality.

III. Determine the amount of oil repellent added

The amount of oil repellent added is generally 0.1% - 2% of the total system amount, but the specific value needs to be determined through experiments. You can prepare multiple groups of the same water-based plastic paint samples, add different proportions of oil repellent, and conduct coating tests on the same substrate to observe the surface effect of the paint film, such as whether there are shrinkage holes, oil spots, and the flatness and finish of the coating film, and choose the amount of addition that can achieve the best coating effect. During the test, the effect of the amount of oil-repellent added on other properties of the coating, such as drying speed and adhesion, should also be considered.

2. Addition steps of oil-repellent

I. Dilution (if necessary)

For some oil-repellents with high active ingredients, in order to make them more evenly dispersed in the coating system, it is recommended to dilute them with a solvent such as dimethylbenzene to a 10% solution before use. During the dilution process, the oil-repellent and solvent should be accurately measured in the correct proportion, and a clean stirring device should be used to stir them thoroughly to ensure that the oil-repellent is completely dissolved in the solvent.

II. Addition process

In the production process of water-based plastic paint, oil-repellent can be added at multiple stages, but in order to ensure its uniform dispersion, it is recommended to add it slowly during the stirring process. During the specific operation, adjust the stirring equipment to a suitable speed to avoid a large number of bubbles due to too fast a speed or uneven dispersion of the oil-repellent due to too slow a speed. Slowly pour the diluted oil-repellent solution or undiluted oil-repellent along the inner wall of the stirring container and continue stirring for 10-15 minutes to fully integrate the oil-repellent into the coating system. During the addition process, closely observe the state of the paint, such as whether there are abnormal phenomena such as stratification and flocculation.

III. Mix evenly

After adding the oil-resistant agent, continue to stir the paint to ensure that the oil-resistant agent and the water-based plastic paint are completely mixed and evenly. You can use a circular stirring or multiple stirring method to further improve the mixing effect. After stirring, let the paint stand for a while to observe whether its surface is flat, whether there are floating objects or precipitation, and ensure that the paint system is stable before coating.

3. Precautions during use

I. Compatibility test

Before the formal large-scale use of oil-resistant agents, be sure to conduct a compatibility test. Compare the water-based plastic paint with the oil-resistant agent added with the original paint without adding it to observe whether there are differences in appearance, drying performance, hardness, adhesion, etc. If incompatibility occurs, such as flowery and peeling phenomena on the surface of the paint film, it is necessary to change the type of oil-resistant agent or adjust the method of use in time.

II. System pH Control

The performance of some oil-resistant agents will be affected by the pH value of the system. For example, non-silicon modified polymer oil-resistant agents may hydrolyze under acidic or alkaline conditions, thereby reducing the oil-resistant effect. Therefore, during use, the pH value of the water-based plastic paint system should be regularly tested and controlled within an appropriate range. Generally speaking, the pH value of water-based plastic paint should be kept between 7 and 9, which can be adjusted by adding pH regulators.

III. Storage conditions

Oil-resistant agents should be stored in a cool, dry, and ventilated place, avoiding direct sunlight and high temperature environments. High temperatures may cause the active ingredients in the oil-resistant agent to decompose or volatilize, affecting its performance. At the same time, keep away from fire sources and oxidants to prevent safety accidents such as fire or explosion. During storage, regularly check whether the packaging of the oil-resistant agent is intact to avoid moisture or contamination of the oil-resistant agent due to packaging damage.

IV. Safety protection

Although most water-based plastic paint oil-resistant agents are environmentally friendly and non-toxic, safety protection measures are still required during use. Operators should wear protective gloves, masks, goggles and other protective equipment to avoid contact between the oil repellent and the skin and eyes. If contact is made accidentally, rinse immediately with plenty of water and seek medical attention in time. In places where oil repellents are used and stored, good ventilation conditions should be maintained to prevent the accumulation of volatile gases.

Correct use of water-based plastic paint oil repellent is the key to ensuring the quality of coating. By doing a good job of preparation before use, standardizing the addition steps and strictly following the precautions, the performance advantages of the oil repellent can be fully utilized, the problem of paint film defects can be effectively solved, and the coating effect and quality of plastic products can be improved.