PE and PP Industrial Bag Closing Thread

Nam Phat Plastic manufactures and supplies industrial bag closing thread for packaging factories, packing facilities, agricultural warehouses, animal feed manufacturers, and businesses that use bag sewing machines.

Our main product range includes PE 20/6, 20/8, and 20/9 bag closing thread, as well as PP 900D, 1000D, and 1200D thread. Thread color, cone weight, core type, and packaging can be customized according to actual operating requirements.

For bag closing thread, tensile strength is only one part of overall product performance. A suitable thread must also have consistent twist, uniform winding, smooth unwinding, minimal tangling, and a low risk of breaking or fraying during continuous machine operation.

For this reason, Nam Phat recommends selecting bag closing thread according to the type of bag, packed weight, sewing machine, and operating speed rather than comparing products solely by price per kilogram.

What Is Industrial Bag Closing Thread?

Bag closing thread is a specialized sewing thread used to close the opening of a bag or connect layers of packaging material during the packing process.

It is widely used for:

• Woven PP bags
• Multiwall paper bags
• Agricultural produce bags
• Rice bags
• Animal feed bags
• Flour bags
• Fertilizer bags
• Various other types of industrial packaging

Unlike garment sewing thread, bag closing thread normally operates on thick, rough materials at relatively high sewing speeds. During handling, the seam must also withstand pulling forces when bags are lifted, stacked, transported, or exposed to impact.

Therefore, bag closing thread must meet several requirements at the same time:

• The thread should have reasonably consistent thickness.
• The twist level should be suitable and should not be too loose or too hard.
• The thread should unwind evenly with minimal tangling or loop slippage.
• It should be compatible with the needle, thread tension, and machine speed.
• The seam should be strong without tearing the edge of the bag.
• The cone weight and dimensions should fit the machine’s thread stand.

There is no single thread specification that is suitable for every type of bag and every sewing machine. Testing a sample directly on the actual machine remains the most reliable method before placing a large-volume order.

Bag Closing Thread Supplied by Nam Phat

1. PE 20/6, 20/8, and 20/9 Bag Closing Thread

PE bag closing thread is made from PE 20/1 single yarn. The required number of single yarns is combined, twisted, and wound into finished cones.

In specifications such as 20/8 or 20/9, the number after the slash indicates the number of single yarns combined in the finished thread structure.

Therefore:

• PE 20/6 consists of six single yarns.
• PE 20/8 consists of eight single yarns and is commonly known as C8.
• PE 20/9 consists of nine single yarns and is commonly known as C9.

PE 20/8 and PE 20/9 are widely used for sewing rice bags, animal feed bags, agricultural produce bags, flour bags, and other common packaging bags.

The thread can be used on portable bag closing machines or fixed industrial bag sewing machines when the correct cone size is selected and the machine is properly adjusted.

Nam Phat currently supplies PE thread in cone weights ranging from approximately 0.2 to 3 kilograms. Multiple colors are available, and samples can be provided for testing before customers place large orders.

PE 20/9 should not automatically be considered better than PE 20/8. A thicker thread may provide greater strength in certain applications, but it may also produce a stiffer seam, increase friction at the needle, or make thread tension more difficult to adjust when the machine and needle are not suitable.

2. PP 900D, 1000D, and 1200D Bag Closing Thread

PP thread is manufactured from polypropylene filament yarn and is classified according to yarn size, such as 900D, 1000D, or 1200D.

Under the same raw material and manufacturing conditions, a higher denier generally indicates a larger and heavier yarn. However, actual load-bearing performance also depends on:

• Yarn quality
• Drawing and elongation characteristics
• Number of filaments
• Twist level
• Finished cone winding quality

PP thread is commonly selected for:

• Woven PP bags
• Heavy-duty industrial sacks
• Fertilizer bags
• Raw material bags
• Mesh bags
• Certain jumbo bags or products requiring a heavier seam
• Weaving, knitting, and suitable technical applications

Nam Phat currently offers separate PP 900D, 1000D, and 1200D product specifications. Common cone weights range from approximately 2 to 8 kilograms. The thread can be produced in white or customized colors.

When selecting between PP 900D, 1000D, and 1200D, customers should not consider only the filled weight of the bag. Other important factors include:

• Thickness of the bag edge
• Number of folded layers
• Needle type and size
• Stitch length
• Production line speed

Using a thread that is too large with a small needle may increase friction, cause the needle to overheat, or result in filament fraying.

3. Colored and Multicolored Bag Closing Thread

In addition to standard white thread, bag closing thread can be manufactured in red, blue, yellow, or a combination of multiple colors.

Colored thread is not used only for appearance. Many businesses use seam colors to:

• Identify different product categories
• Distinguish production shifts or batches
• Inspect seam condition quickly
• Classify goods in the warehouse
• Create a unique identification feature for the business

When ordering colored thread, customers should provide a physical color sample or reference color code. Colors displayed on a mobile phone or computer screen may differ from the actual finished product.

Recommended Thread Selection by Application

Application	Thread to Test	Important Considerations
25–50 kg rice bags	PE 20/8 or PE 20/9	Check the bag material, needle, and thread tension
Animal feed bags	PE 20/8 or PE 20/9	Prioritize uniform winding for continuous production lines
Agricultural produce, corn, beans, and dried grain bags	PE 20/8 or PE 20/9	Select the color and cone weight according to operating requirements
Woven PP bags and fertilizer bags	PP 900D–1200D	Test according to the thickness of the folded bag edge and filled weight
Large sacks or applications requiring a heavier seam	PP 1200D or another suitable specification	A machine trial and seam inspection are required
Portable bag closing machines	PE or PP in small cones	Check the dimensions of the thread stand
Fixed industrial bag sewing machines	Larger cones with stable unwinding	Larger cones help reduce the frequency of cone replacement
Batch identification	Colored or multicolored thread	Confirm the physical color sample before production

The table above provides only an initial recommendation. The final specification should be selected according to the bag sample and actual machine operating conditions.

What Determines Stable Sewing Machine Performance?

Thread Uniformity

If the thread contains unusually thick or thin sections, or if joints are not properly processed, it may become caught in the thread guides, needle eye, or tensioning assembly.

This can cause inconsistent thread breakage. The machine may run normally at one time but experience repeated breakage at another, making it difficult for the operator to identify the cause.

Appropriate Twist Level

If the twist is too low, the component yarns may separate, become fuzzy, or catch in the thread guides.

If the twist is too high, the thread may become excessively stiff, develop reverse twisting, or form loops as it unwinds from the cone.

The appropriate twist level must be balanced according to:

• Yarn structure
• Thread specification
• Machine type
• Sewing speed

Cone Shape and Winding Quality

A good cone must not only have the correct weight but must also be wound evenly and consistently.

A cone that is too soft may collapse, allow loops to slip, or cause tangling. A cone that is wound too tightly may place the thread under tension during storage.

For continuously operating production lines, cone stability directly affects the number of machine stoppages during each shift.

Needle Condition and Thread Tension

In many cases, thread breakage is not caused entirely by thread quality.

Possible causes include:

• A dull needle
• A needle eye that is too small
• A bent needle
• Burrs or rough surfaces on the thread guides
• Excessive thread tension

These conditions may cause the thread to fray and break quickly.

When changing to a new thread batch, at least three factors should be checked before determining the cause of a problem:

1. Needle condition and size
2. Thread path
3. Thread tensioning system

Stitch Length

If the stitch length is too short, the needle penetrates the bag more frequently. This increases thread consumption and may create a perforated tear line along the bag edge.

If the stitch length is too long, the seam becomes too open and may not close the bag securely.

Stitch length should be adjusted according to:

• Bag material
• Thickness of the folded edge
• Required seam strength

Bag Closing Thread Should Not Be Evaluated Only by Price per Kilogram

For packaging factories, a lower-priced thread does not necessarily result in a lower operating cost.

The actual cost also includes:

• Thread consumption per finished bag
• Number of thread breaks during each shift
• Machine downtime for reconnecting thread or replacing cones
• Number of bags that require resewing
• Risk of the bag opening during transportation
• Product loss caused by seam failure

A stable thread can reduce machine downtime and defective products. Therefore, businesses should compare the thread cost per finished bag rather than comparing only the purchase price per kilogram.

Custom Bag Closing Thread Specifications

Depending on the product line, Nam Phat can discuss the following specifications with customers:

Specification	Available Options
Thread material	PE or PP
PE specifications	20/6, 20/8, and 20/9
PP specifications	900D, 1000D, and 1200D
Color	White, red, blue, yellow, or customized according to a sample
Cone weight	Small or large cones according to the sewing machine
Cone core	Paper tube or plastic tube
Packaging	PP bags, PE bags, or cartons
Trial sample	Discussed according to the required specification and application
Minimum order quantity	Confirmed according to the color and product type
Delivery time	Depends on the quantity, specification, and production schedule

To minimize specification differences, customers who are currently using an existing thread should provide an old cone sample or information from the product label.

Nam Phat can use the sample as a reference to verify the thread specification before production.

Consultation and Sample Testing Process

Step 1: Collect Application Information

The customer provides information about:

• Type of bag
• Filled weight per bag
• Sewing machine model
• Current thread specification
• Problems currently experienced during operation

Step 2: Select an Initial Specification

Nam Phat recommends a suitable PE or PP thread, yarn size, cone weight, and color according to the customer’s operating requirements.

Step 3: Provide a Trial Sample

The sample is tested directly on the customer’s machine to evaluate:

• Thread unwinding performance
• Filament fraying
• Operating stability
• Finished seam appearance

Step 4: Make Adjustments When Necessary

If the seam is not satisfactory, it is necessary to determine whether the problem is caused by the thread specification or the machine settings.

The thread specification should not be changed repeatedly before the needle, thread tension, and thread guides have been properly inspected.

Step 5: Confirm Commercial Production

After the sample operates consistently, both parties confirm:

• Thread color
• Cone weight
• Core type
• Packaging
• Order quantity

Why Do Industrial Customers Choose Nam Phat?

Production Based on Actual Operating Requirements

Nam Phat does not simply supply products according to a general thread name. We can recommend a specification based on the bag type, sewing machine, cone requirements, and operating conditions.

Multiple PE and PP Thread Options

Customers can select products ranging from PE 20/6–20/9 to PP 900D–1200D rather than using a single thread specification for every application.

Customized Colors and Cone Specifications

Thread color, cone weight, core type, and packaging can be customized according to production or distribution requirements.

Sample Testing Before Large Orders

Sample testing allows customers to evaluate the thread directly on their machines. This reduces the risk of purchasing a large batch that is not compatible with the actual application.

Focus on Consistency Across Repeat Orders

For industrial customers, achieving acceptable performance in the first order is not enough.

Color, yarn structure, twist level, and cone specifications should remain consistent across repeat orders to reduce the need for machine readjustment.

Frequently Asked Questions About Bag Closing Thread

What Is the Difference Between PE and PP Bag Closing Thread?

The two product groups have different structures and classification methods.

PE thread is normally identified by specifications such as 20/6, 20/8, and 20/9. PP thread is generally identified by yarn size, such as 900D, 1000D, and 1200D.

The appropriate product should be selected according to the bag material, sewing machine, and seam requirements.

Should PE 20/8 or PE 20/9 Be Used for Rice Bags?

Both specifications can be used for rice bags.

PE 20/9 contains more single yarns in its structure, but not every machine requires a larger thread. The thread should be tested directly with the actual 25 kg or 50 kg rice bag.

Is PP 1200D Always Stronger Than PP 900D?

PP 1200D has a larger yarn size than PP 900D. However, seam strength does not depend only on the denier value.

Other important factors include:

• Yarn quality
• Twist level
• Needle type and size
• Stitch length
• Structure of the folded bag edge

Can Nam Phat Thread Be Used on Portable Bag Closing Machines?

PE thread and certain PP specifications can be used on many portable bag closing machines.

However, customers should check the cone dimensions, thread stand, needle, and thread tension adjustment of each machine.

Can Thread Be Produced in a Custom Color?

Nam Phat can discuss the production of white, red, blue, yellow, or custom-colored thread according to a customer sample.

For special colors, customers should approve a physical color sample before placing a large-volume order.

Can Customers Receive a Sample Before Ordering?

Customers can request samples for testing with their actual bags and sewing machines.

Sample testing is particularly important when changing from an existing supplier to a new thread specification.

How Is the Price of Bag Closing Thread Calculated?

The price depends on:

• Type of raw material
• PE or PP specification
• Color
• Cone weight
• Order quantity
• Packaging requirements

To receive an accurate quotation, customers should provide complete application information rather than requesting only a general price per cone.

Contact Us for a Quotation and Trial Sample

To help Nam Phat provide a fast and accurate recommendation, customers should send:

• A photograph of the thread cone currently being used
• Type of bag and filled weight per bag
• Bag sewing machine model
• Required cone weight
• Required color
• Estimated monthly consumption

Nam Phat Plastic

Hotline: 0911 904 968
Email: contact.namphat@gmail.com

Products: PE bag closing thread, PP bag closing thread, rice bag sewing thread, animal feed bag sewing thread, and colored bag closing thread.