1. Overview of methyl hydroxyethyl cellulose (MHEC)
Methyl hydroxyethyl cellulose (MHEC) is a non-ionic cellulose ether obtained by methylation modification on the basis of hydroxyethyl cellulose. Due to its unique molecular structure, MHEC has good solubility, thickening, adhesion, film-forming and surface activity, and has been widely used in coatings, building materials, daily chemicals and other fields.
2. Overview of paint strippers
Paint strippers are chemical preparations used to remove surface coatings such as metals, wood, and plastics. Traditional paint strippers mostly rely on harsh solvent systems, such as dichloromethane and toluene. Although these chemicals are effective, they have problems such as high volatility, toxicity and environmental hazards. With the increasingly stringent environmental regulations and the improvement of working environment requirements, water-based and low-toxic paint strippers have gradually become the mainstream of the market.
3. Mechanism of action of MHEC in paint strippers
In paint strippers, MHEC plays an important role as a thickener and rheology modifier:
Thickening effect:
MHEC has a good thickening effect in water-based systems. By adjusting the viscosity of the paint stripper, MHEC can make the paint stripper adhere to vertical or inclined surfaces without sagging. This property is particularly important during the application of paint strippers because it allows the paint stripper to remain on the target surface for a longer time, thereby improving the paint stripping effect.
Stabilize the suspension system:
Paint strippers usually contain various active ingredients, which may stratify or settle during storage. By enhancing the structural viscosity of the solution, MHEC can effectively prevent the sedimentation of solid particles, maintain the uniform distribution of ingredients, and ensure the stable performance of the paint stripper.
Adjust rheological properties:
The use of paint strippers requires that it has good rheological properties, that is, it can flow smoothly when external force is applied, but can thicken quickly when stagnant. The molecular chain structure of MHEC gives it good shear thinning properties, that is, at high shear rates, the viscosity of the solution will decrease, making the paint stripper easier to apply; while at low shear rates or in a static state, the solution viscosity is high, which helps the material form a uniform coating on the target surface.
Promote film formation:
During the paint stripping process, MHEC can help the paint stripper form a uniform film on the target surface. This film can not only prolong the action time of the active ingredients, but also enhance the covering ability of the paint stripper to a certain extent, so that it can effectively penetrate into all parts of the coating.
4. How to use MHEC in paint strippers
Preparation of aqueous solution:
MHEC usually exists in powder form and needs to be prepared into an aqueous solution before use. The general practice is to slowly add MHEC to the stirred water to avoid agglomeration. It should be noted that the solubility of MHEC will be affected by water temperature and pH value. Higher water temperature (50-60℃) can accelerate the dissolution process of MHEC, but too high temperature will affect its viscosity performance.
Mixed into paint strippers:
When preparing paint strippers, MHEC aqueous solution is usually slowly added to the paint stripper base liquid under stirring. In order to ensure uniform dispersion, the addition speed of MHEC should not be too fast, and stirring should be continued until a uniform solution is obtained. This process requires controlling the stirring speed to prevent the formation of bubbles.
Adjustment of formula:
The amount of MHEC in paint strippers is usually adjusted according to the specific formula and target performance of the paint strippers. The common addition amount is between 0.1%-1%. Too strong thickening effect may cause uneven coating or excessive viscosity, while insufficient dosage may not achieve the ideal viscosity and rheological properties, so it is necessary to optimize its usage through experiments.
5. Advantages of MHEC in paint strippers
Safety and environmental protection:
Compared with traditional thickeners, MHEC is a non-ionic cellulose ether, does not contain toxic and harmful substances, is safer for human body and environment, and is in line with the development direction of modern green chemistry.
Excellent stability: MHEC has good chemical stability in a wide pH range (pH 2-12), can maintain a stable thickening effect in various paint stripper systems, and is not easily interfered by other components in the system.
Good compatibility: Due to the non-ionic nature of MHEC, it is well compatible with most active ingredients, will not interact or cause system instability, and is suitable for various types of paint stripper formulations.
Efficient thickening effect: MHEC can provide a significant thickening effect, thereby reducing the amount of other thickeners in the paint stripper, simplifying the formula and reducing costs.
Methyl hydroxyethyl cellulose (MHEC) has been widely used in modern paint strippers due to its excellent thickening, stability and compatibility. Through reasonable formula design and use, MHEC can significantly improve the performance of paint strippers, making them show higher efficiency and environmental protection in practical applications. In the future, with the continuous development of paint stripper technology and the further improvement of environmental protection requirements, the application prospects of MHEC in paint strippers will be broader.
Post time: Jun-14-2024