Interlining in Garment Manufacturing

Interlining is basically anything used between 2 layers of fabric to give more body. A fusible interlining is a thin layer made from woven, knitted or non-woven material bonded mechanically or thermally which when fused with fabric panel can give reinforcement, durability and can also stabilize and makes sewing work easier while sewing.

Interlining Types

• Woven Interlinings made from lightweight fabrics usually used for most demanding conditions like the waistband, outerwear plackets, jackets etc.
• Knitted Interlinings – Fusible, knitted interlinings are basically used in knit garments with stretchable fused areas also. These provide the perfect basis for efficient production. Circular and jersey knit fusible interlines have stretch and recovery properties.
• Non-woven Interlines – High quality non-woven interlines are made from 100% polyamide products with an ultra-fine coating to heavier blends. These are thermally or chemically bonded and used depending on applications. Generally available in very light weights of 100 gms up to 100 gms.
• Water Repellent Interlines are thermal bonded, non-woven specifically designed for rainwear piece goods. Thermally bonded non-woven and circular knits can withstand the rigors of commercial wash processes such as garment wash, enzyme wash, stone wash, bleach wash etc.
• Embroidery backings are made from nonwoven nonfusible interning materials which are easily tearable. For washed garments nonwoven interlines are now available which are easily soluble in hot or even normal water.
• Hair Interlines are woven canvas made from horse hair mostly used in men’s formal jackets, blazers etc.

Fusing Recommendations

A perfect working fusing press and appropriate conditions are needed to achieve good results. Only an exact balanced combination of temperature, pressure and time can guarantee and excellent adhesion. Therefore the temperature, pressure and dwell time should be often checked periodically every day and well documented.

The whole scale of fabrics should be tested before starting the production. Not just for fusing, but also for steam pressing, ironing, etc. Start production only after this checking. Big differences may influence the results. Before using a specific type of interlining for bulk production always refer to test report containing analysis and recommended settings for using the material.

Always check before starting bulk

• Dwell time
• Roller pressure
• Fuse line temperature
• Fusing Condition like thermostat setting
• Bond Strength
• Surface appearance
• Dimensional change

Machine Check-up

• External appearance – area must be tidy and clean of any foreign yarns or fabric dust (cutting dust)
• Heat Changer – it must be dust free and belt must be clean at all times for better fusing results
• Belt – it is most frequently used part of the machine and must be free from any distortion and breakage or otherwise must be changed. Remember to change both upper and lower belt for best results and avoid causing different friction between both the belts.
• Pressure balance on a roller – all rollers must be checked to keep the belt in parallel and tight in line misaligned rollers can also greatly reduce good results.
• Thermostat – it must always function correctly. Must ensure to check manually using thermo papers and electronic thermometer.
• Timer/Speed meter – must function correctly to get the correct dwell time otherwise fusing conditions might not meet giving poor fusing results.

Good fusible Interlines must have

• Good bond Strength
• Good peel bond after wash
• Controlled differential shrinkage
• Active shrinkage and elongation through the wash and dry process
• Does not get affected due to steaming
• Can withstand overheat and pressure

Non-woven fusible interlines

Buyer advice test methods and minimum required standards for fusible interlinings to be used on specific fabrics. These standards include mass, bursting strength, flexibility and durability, and dimensional change on cold water immersion and minimum tensile strength in the warp direction. Heat shrinkage and dry-cleaning shrinkage of fusible interlinings are considered as important. Basically, there are 4 types of non woven interlines based on construction.

• Random: Fibres are arranged multidirectional in a random manner, providing stability and strength along with suppleness and flexibility. Can be good for medium to heavy weight fabrics.
• Parallel: Fibres are arranged in parallel. Good for Knitwear fabrics.
• Cross: Fibres are laid diagonally giving extensible and versatile regain properties. These interlines are very stable at a slight angle therefore suitable for soft and flexible outer fabrics.
• Composite: These interlines are laminates made from 2 types of fiber lay, for example, random and parallel or parallel with a cross. These are used for general purpose due to its balanced properties.

Fusing Procedure

• Always ensure the fusing machine is properly heated up before starting bulk production every day or shift. Always test using same bulk panels.
• Interlining must be at least 2 mm shorter all around the fabric panel to be fused.
• Never cut interlining larger than the fabric. This way, the glue will contaminate the conveyor belt and fabric.
• Use carrier sheets while loading the fusing panels to ensure that the interning panel is not moved while loading
• Fusing speed, roller pressure and temperature must be correct as specified by supplier otherwise any incorrect standard will result in defective poor fusing quality.
• Never use a sandwich or multilayer fusing to save time. This will result in poor fusing quality.
• Machine head changed must be checked for uniform temperature otherwise poor quality fusing will result.
• If fusing by hand iron then iron must be placed firmly with weight and must not be slide across the panel.
• Proper maintenance of machine is done on a regular basis
• Never use steam iron for using panels
• Do not blow cold air around fusing machine but rather use a well-ventilated area for good working atmosphere
• Always do testing by coordinated matching of fabric and interlining in warp and weft direction
• Interning must always be fused with interning on top of the fabric and not upside down.

Defects due to incorrect usage of interning on appearance

• Moire – surface optical effect between two fabrics
• Bubbling – localized de-lamination
• Strike Back – Glue penetrates back through interning
• Orange Skin – Surface distortion by shrinkage difference
• Strikethrough – Glue penetrated through the fabric and comes to face side.