Wet Strength Agent

2026-06-11 10:15

1. Definition

A wet strength agent is a functional papermaking additive. It prevents paper from disintegrating when exposed to water and greatly improves the wet strength of paper.
The wet strength of ordinary paper is only 4%–10%, while paper treated with wet strength agents can reach 20%–50%. Paper with wet strength no less than 15% is defined as wet-strength paper.

2. Four Main Types (Brief Differentiation)

  1. PAE (Dominant product): Zero/low formaldehyde, applicable under neutral conditions, well-balanced performance, widely used for household and packaging paper. Dosage: 0.3%–1.5%.

  2. MF/UF (Traditional aldehyde-based agents): High wet strength, low cost; contains formaldehyde and is non-environmentally friendly, gradually being phased out.

  3. PEI: Strong adsorption capacity, mainly applied to filter paper and special industrial paper.

  4. Bio-based agents (Starch/Chitosan): Food-grade, biodegradable and safe; relatively low wet strength and high cost.

3. Mechanism of Action

  1. It cross-links to form a waterproof film to block water and prevent fiber swelling.

  2. It forms water-resistant chemical bonds with cellulose to retain paper strength.

  3. Its cationic property enables adsorption onto fibers, ensuring high retention rate and stable performance.

4. Key Process Parameters

Optimal pH range: Neutral, 6.5–8.5
Pulp temperature: 45–65℃
Curing temperature: 100–120℃ (for finalizing wet strength)
Feeding position: Wet end of paper machine (mixing tank / fan pump)

5. Notes on Application

  • Excessive dosage will cause paper stiffness, fiber flocculation and difficult broke repulping.

  • Storage conditions: 5–35℃, avoid freezing and high temperature. Shelf life: 3–6 months.

6. Industry Trends

Formaldehyde-free products, high solid content, bio-based materials, and multi-functional compound additives (wet strength + retention aid + antibacterial property).


声明：此篇为 Shandong Yongsheng Chemical Co., Ltd. 原创文章，转载请标明出处链接： https://www.sdyshx.com/en/sys-nd/416.html
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