How to Choose the Appropriate Yarn Strength for Acrylic Yarn

Acrylic yarn is a type of synthetic fiber yarn with many unique physical and chemical properties. Understanding these fundamental characteristics is essential for selecting the appropriate yarn strength.

1.1 Composition of Acrylic Fiber

Acrylic fiber (polyacrylonitrile fiber) is a high-molecular compound polymerized from acrylonitrile monomers, typically containing over 85% acrylonitrile monomers. This chemical structure endows acrylic fiber with excellent lightfastness, weather resistance, and chemical stability.

1.2 Physical Performance Characteristics

Acrylic yarn possesses the following notable characteristics:

Light weight (1.14-1.19 g/cm³)

Good elasticity

Excellent thermal insulation performance

Outstanding sun resistance

Excellent anti-wrinkle performance

Strong resistance to acids and alkalis

1.3 Mechanical Performance Manifestation

In terms of mechanical properties, acrylic yarn has moderate strength, typically ranging from 2.5 to 3.5 cN/dtex in dry state, with wet state strength being 80%-90% of the dry state. It exhibits high elongation at break, generally between 25%-50%.

II. Factors Affecting Yarn Strength

When selecting the strength of acrylic yarn, it is necessary to consider the combined influence of multiple factors.

2.1 Characteristics of the Fiber Itself

The molecular weight, crystallinity, and orientation of fibers directly affect yarn strength. Acrylic fibers with high polymerization degree, high crystallinity, and high orientation typically provide higher yarn strength.

2.2 Yarn Structure Parameters

2.2.1 Yarn Count

Yarn count (fineness) is closely related to strength. Generally, the coarser the yarn (the lower the count), the higher the absolute strength; however, the relative strength (strength per unit fineness) may decrease.

2.2.2 Twist

Twist has a dual effect on yarn strength:

Appropriately increasing the twist can enhance the inter-fiber cohesion and improve yarn strength

Excessive twist causes fibers to tilt excessively, thereby reducing yarn strength

2.2.3 Yarn Structure

Different yarn structures (such as single yarn, ply yarn, and core-spun yarn) significantly affect strength. Ply yarns generally exhibit 20%-50% higher strength than single yarns.

2.3 Production Process Factors

Parameters such as the drafting ratio, temperature control, and post-processing techniques in the spinning process all affect the final yarn strength. Optimizing these process parameters can significantly enhance yarn strength.

2.4 Environmental Conditions

Environmental factors such as temperature and humidity can affect the strength performance of acrylic yarn. The strength of acrylic decreases at high temperatures, and its wet strength is generally lower than its dry strength.

3、 Selection criteria for yarn strength

The standard for selecting the strength of acrylic yarn varies depending on different application scenarios.

3.1 End use requirements

3.1.1 Clothing yarn

Knitted clothing: usually choose medium strength (2.8-3.2cN/dtex), emphasizing softness and elasticity

Woven clothing: Higher strength (3.0-3.5cN/dtex) can be selected to meet weaving tension requirements

Sweater yarn: requires relatively low strength (2.5-3.0 cN/dtex), emphasizing fluffiness and warmth

3.1.2 Home Textile Yarn

Curtain yarn: requires high strength (3.2-3.8cN/dtex) and light resistance

Carpet yarn: requires high strength (3.5-4.0 cN/dtex) and wear resistance

Decorative fabric: Medium strength (3.0-3.5cN/dtex) that balances aesthetics and durability

3.1.3 Industrial yarn

Filter material: requires high strength (3.8-4.5cN/dtex) and chemical resistance

Industrial fabric: choose different strength grades according to specific applications

Rope: Ultra high strength requirement (4.0 cN/dtex or above)

3.2 Processing Technology Requirements

Requirements for yarn strength for different processing techniques:

3.2.1 Weaving process

High speed weaving machine: requires high strength yarn to reduce breakage rate

Traditional weaving machines: strength requirements can be appropriately reduced

Jacquard fabric: higher strength required due to complex organizational structure

3.2.2 Knitting process

Circular knitting: moderate strength is sufficient

Horizontal knitting: choose different strengths based on product thickness

Warp knitting: usually requires high-strength yarns

3.2.3 Post printing and dyeing finishing

Consider the chemical and mechanical effects during the post-processing process, and choose yarns of appropriate strength to avoid damage.

3.3 Cost benefit balance

High strength yarns are usually expensive and require a balance between performance requirements and cost. For non critical parts or products for short-term use, the strength requirements can be appropriately reduced to save costs.

4、 Testing and Evaluation of Yarn Strength

Scientific testing and evaluation are important steps in selecting appropriate yarn strength.

4.1 Common Testing Methods

4.1.1 Single yarn strength test

The most direct strength evaluation method is to use an electronic strength tester to measure the breaking strength and elongation of a single yarn.

4.1.2 Yarn Strength Test

Test the strength of a certain length of yarn bundle, suitable for evaluating the strength of strands or thicker yarns.

4.1.3 Wear resistance test

Evaluate the durability of yarn by simulating the friction situation in actual use.

4.2 Interpretation of Strength Indicators

4.2.1 Absolute Strength

The maximum force that the yarn can withstand when it breaks, measured in newtons (N) or millinewtons (cN).

4.2.2 Relative Strength

The strength per unit fineness, measured in cN/dtex or cN/tex, facilitates comparison between yarns of different fineness.

4.2.3 Elongation at break

Reflecting the toughness of the yarn, it determines the mechanical properties of the yarn together with its strength.

4.3 Evaluation of strength unevenness

The uniformity of yarn strength is equally important, usually represented by the coefficient of variation (CV). The CV value of high-quality yarn strength should be controlled below 10%.

5、 Suggestions for selection in practical applications

Based on practical experience, the following practical suggestions are provided:

5.1 Selection strategy for new product development

Clearly define the performance requirements and usage environment of terminal products

Refer to the yarn strength indicators of similar products

Conduct sample production and performance testing

Adjust yarn strength selection based on test results

Optimize cost structure

5.2 Solutions to Common Problems

5.2.1 Insufficient yarn strength

Improve yarn twist

Choose higher strength fiber raw materials

Switching to a stock line structure

Optimize spinning process parameters

5.2.2 Excessive yarn strength leads to poor hand feel

Reduce yarn twist appropriately

Choose finer fibers

Blended with low strength and high elongation fibers

Adjust the post-treatment process

5.3 Response methods for special needs

For applications with special strength requirements:

Super demand: Consider blending acrylic fiber with high-strength fibers (such as aramid)

Elastic demand: Choose low strength high elongation yarn or core spun yarn structure

High temperature resistance requirement: Select specially modified acrylic fiber

6、 Future Development Trends

With the advancement of technology, the strength selection of acrylic yarn will show the following trends:

6.1 High performance

Developing higher strength acrylic fibers through techniques such as nano modification and copolymerization modification to expand their application fields.

6.2 Differentiated Development

Develop specialized strength grades of acrylic yarn for different application scenarios to achieve more accurate performance matching.

6.3 Intelligent selection

Using big data and artificial intelligence technology, establish an intelligent recommendation system for yarn strength selection to improve selection efficiency and accuracy.

Conclusion

Choosing the appropriate strength of acrylic yarn is a decision-making process that requires comprehensive consideration of multiple factors. From fiber characteristics to end use applications, from production processes to cost control, every link may affect the final choice. Only through scientific testing and practical verification, combined with rich industry experience, can the most suitable strength of acrylic yarn be selected for specific applications. With the advancement of material technology, more high-performance acrylic yarns will emerge in the future, providing the textile industry with richer choices.