What are the commonly used adhesive thickeners?

Adhesive thickeners play a vital role in modern industry and daily life. They not only increase the viscosity and stability of adhesives, but also improve their rheology and application performance. The following will discuss in detail several commonly used adhesive thickeners, including natural thickeners, synthetic thickeners and their specific applications.

### 1. Natural thickeners

#### 1.1 Cellulose derivatives

**Hydroxypropyl methylcellulose (HPMC)**: HPMC has good thickening, water retention, film-forming and bonding properties, and is widely used in construction adhesives (such as tile adhesives, putty powder), coatings and food industries.

**Carboxymethyl cellulose (CMC)**: CMC is a water-soluble cellulose derivative with good thickening, film-forming and stabilizing properties, and is commonly used in water-based adhesives, coatings and food industries.

**Methyl cellulose (MC)**: MC is used as a thickener and binder in the construction and coatings industries, providing excellent fluidity and construction performance.

#### 1.2 Natural gums

**Guar gum**: Guar gum is a natural polysaccharide extracted from the seeds of leguminous plants. It has high thickening properties and is widely used in the food industry, oil drilling fluids and building adhesives.

**Xanthan gum**: Xanthan gum is a polysaccharide produced by bacterial fermentation. It has excellent thickening and stabilizing properties and is commonly used in food, cosmetics and industrial adhesives.

#### 1.3 Seaweed extracts

**Sodium alginate**: Sodium alginate is a natural polysaccharide extracted from brown algae. It has excellent thickening and film-forming properties and is widely used in food, textile printing and dyeing and industrial adhesives.

**Carrageenan**: Carrageenan is a natural polysaccharide extracted from red algae. It has good thickening and gelling properties and is mainly used in the food industry and biomedicine.

### 2. Synthetic Thickeners

#### 2.1 Acrylic Thickeners

**Polyacrylic acid (PAA)**: Polyacrylic acid and its salts are commonly used synthetic thickeners with excellent thickening properties and acid-base stability. They are widely used in water-based adhesives, coatings, personal care products and detergents.

**Acrylic acid copolymers**: Copolymers formed by the copolymerization of acrylic acid with other monomers, such as acrylate-acrylic acid copolymers, have good thickening and rheology modification properties and are commonly used in coatings, adhesives and emulsion polymers.

#### 2.2 Polyvinyl alcohol (PVA)

PVA is a water-soluble polymer compound with excellent thickening, film-forming and bonding properties. It is widely used in paper coating, textile slurry and construction adhesives.

#### 2.3 Polyurethane Thickeners

Polyurethane thickeners are a new type of synthetic thickeners. Through the special structural design of polyurethane, they have excellent thickening, anti-sagging and anti-splashing properties. They are commonly used in water-based coatings and adhesives.

### 3. Other thickeners

#### 3.1 Inorganic thickeners

**Bentonite**: Bentonite is a natural aluminum silicate mineral with good thickening and thixotropic properties. It is widely used in drilling mud, coatings and building adhesives.

**Sodium silicate**: Sodium silicate is a commonly used inorganic thickener with excellent thickening and bonding properties. It is mainly used in building materials, coatings and paper industries.

#### 3.2 Biological thickeners

**Chitosan**: Chitosan is a natural polysaccharide extracted from the shell of crustaceans. It has good thickening, film-forming and antibacterial properties and is commonly used in the food industry, medicine and cosmetics.

**Protein thickeners**: Such as gelatin and casein, this type of thickener has good thickening and gelling properties and is mainly used in the food and medicine fields.

### 4. Selection and application of thickeners

#### 4.1 Considerations for thickener selection

1. **Application scenarios**: Different application scenarios have different requirements for thickeners. For example, building adhesives require high viscosity and anti-sagging performance, while the food industry requires safety and taste.

2. **Viscosity requirements**: Select the appropriate thickener according to the viscosity requirements of the specific application. The viscosity produced by different thickeners at the same concentration varies greatly.

3. **Solubility**: The solubility of the thickener has an important influence on its use effect, and the solubility in water or organic solvents needs to be considered.

4. **Compatibility**: The compatibility of the thickener with other ingredients directly affects the performance of the final product. For example, in coatings, the compatibility of the thickener with pigments and resins needs to be considered.

5. **Environment and safety**: The environmental protection and safety of the thickener are also important considerations for selection, especially in the fields of food and medicine.

#### 4.2 Application of thickeners in adhesives

1. **Building adhesives**: In tile adhesives, putty powder, and gypsum-based materials, thickeners mainly improve the workability, water retention, and anti-sagging properties of the products. Common thickeners include HPMC, MC, and acrylic copolymers.

2. **Industrial adhesives**: In industrial adhesives, thickeners increase the viscosity and stability of adhesives. Common thickeners include PVA, polyacrylic acid, and polyurethane thickeners.

3. **Food adhesives**: In the food industry, thickeners improve the texture and stability of food. Common thickeners include guar gum, xanthan gum, and CMC.

4. **Cosmetic adhesives**: In cosmetics and personal care products, thickeners provide ideal consistency and feel. Common thickeners include HPC, xanthan gum, and acrylic copolymers.

### 5. Development trend and future prospects of thickeners

#### 5.1 Green thickeners

With the increase of environmental awareness, green thickeners have become an important direction for future development. The development of environmentally friendly and degradable natural and biological thickeners, such as chitosan and seaweed extracts, is a hot topic of research.

#### 5.2 High-efficiency thickeners

High-efficiency thickeners are another important direction for future development by improving thickening efficiency and performance and reducing dosage and cost. Through molecular structure design and modification, the thickening efficiency and special properties of thickeners, such as anti-sagging and anti-splashing, are improved.

#### 5.3 Multifunctional thickeners

In the future, the development of thickeners will pay more attention to multifunctionality, not only providing thickening effects, but also having other functions, such as antibacterial, moisturizing, and antistatic. Multifunctional thickeners have broad application prospects in high value-added fields such as cosmetics, medicine, and food.

In summary, adhesive thickeners play an important role in modern industry and daily life. Through continuous research and innovation, the performance and application range of thickeners will continue to expand, providing strong support for the development of related industries.