Plastic rulers are almost universally found on our desks and workstations. They're simple, lightweight, durable, drop-resistant, and moisture-resistant. Some even glow brightly in sunlight. But have you ever wondered what materials these rulers are made of? Why are some transparent, others translucent, and some even fluorescent? Today, we'll explore the technological details hidden within seemingly ordinary plastic rulers from a materials science perspective.
1. Basic Materials of Plastic Rulers: Thermoplastics
Plastic rulers are typically made from several common thermoplastics. The term "thermoplastic" refers to a plastic that softens and flows when heated, then hardens and retains its shape upon cooling, making it suitable for injection molding. The following are some of the most commonly used materials for rulers:
1. Polystyrene (PS)—Transparent and Inexpensive
PS is one of the most common materials used for plastic rulers.
Its advantages include:
High transparency: It appears almost like glass, making it ideal for transparent rulers.
Good moldability: It can easily be molded into graduated rulers. Low cost: Low raw material costs make it ideal for large-scale production.
However, PS also has its drawbacks—it's brittle and prone to cracking if dropped or bent excessively. To enhance its toughness, manufacturers sometimes mix a small amount of modifiers or pigments into PS, giving it a more layered appearance.
2. Acrylic acid (PMMA)—Optically transparent
PMMA is a high-grade plastic often referred to as "plexiglass."
Its main advantages are:
High light transmittance (up to 92%);
Slow yellowing, maintaining clarity over time;
Smooth, textured surface with a firm feel.
PMMA rulers reflect light strongly, giving them a crystal-clear appearance. Many high-end stationery brands use PMMA for precision tools such as rulers and drafting rulers. However, it's expensive and requires more stringent manufacturing processes.
3. Polycarbonate (PC)—Tough and resistant to breakage
PC is slightly less transparent than PMMA, but offers excellent toughness. If you've ever seen a flexible ruler that bends without breaking, it's most likely made of PC or a similar modified plastic.
PC's advantages include:
High impact strength;
High heat resistance;
Good compatibility with fluorescent pigments.
PC is widely used in safety helmets, compact discs, and transparent device cases, so its introduction into rulers is a natural progression.
4. ABS Plastic—A Balance of Strength and Toughness
ABS is a composite resin made from a copolymer of acrylonitrile, butadiene, and styrene.
Its advantages include:
Unbreakable;
Abrasion-resistant;
Slightly bendable.
ABS is not as transparent as PS or PMMA, but by adding additives such as fluorescent pigments and pearlescent powder, it can achieve a translucent or highly saturated, bright appearance.
2. Plastic Ruler Manufacturing Process: From Pellets to Finished Product
Now that we understand the types of plastics, let's take a look at how plastic rulers are manufactured.
The entire process may seem simple, but it actually involves a lot of engineering detail.
1. Raw Material Preparation
The raw material for making plastic rulers is plastic granules. Factories typically add additives such as fluorescent pigments, UV blockers, and antistatic agents to selected plastics (such as PS or PMMA). Fluorescent pigments can create a vibrant, luminescent effect under visible or ultraviolet light.
2. Melt Injection Molding
Plastic pellets are fed into an injection molding machine and heated to 180°C to 250°C, transforming the plastic into a fluid, liquid state.
Then, the plastic is injected into a mold—the mold design determines the ruler's shape, thickness, and graduation placement.
3. Cooling and Demolding
The molded ruler rapidly solidifies in the cooling system, returning to a solid, hard state.
This step requires controlling the temperature gradient to prevent deformation of the plastic due to differential shrinkage.
4. Polishing and Marking
After demolding, the ruler's edges are polished smooth, and the graduations are then applied using screen printing or laser engraving.
Some high-end products use UV-curable ink to enhance the wear resistance of the graduations. 5. Inspection and Packaging
Finally, workers will inspect the transparency, scale accuracy, and fluorescence effect. Only after passing the inspection will the rulers be packaged and shipped.
3. The Role of Fluorescent Pigments in Plastic Rulers
When it comes to eye-catching rulers, fluorescent pigments are indispensable.
These special pigments absorb visible or ultraviolet light and re-emit it as a brighter color.
1. The Basic Principle of Fluorescent Pigments
Unlike ordinary dyes, fluorescent pigments employ an energy absorption-emission conversion mechanism.
When fluorescent molecules absorb light energy, they stimulate electron transitions and rapidly release energy, manifesting as light.
As a result, fluorescent plastic rulers appear brighter than ordinary colors under sunlight or light, and may even appear to be "self-luminous."
2. Compatibility of Fluorescent Pigments with Plastics
Not all pigments can be mixed into plastics.
Fluorescent pigments are typically based on thermoplastic resins (such as PMMA or polyester). They blend well with plastics like PS, ABS, and PC without agglomeration or precipitation. It also has good heat resistance and can withstand the high temperatures (approximately 200°C) experienced during plastic molding.
3. Application Effects
Fluorescent pigments give plastic rulers the following visual and practical advantages:
Enhanced visual appeal: Easier to spot in a school bag or on a desk;
Improved brand recognition: Fluorescent colors often represent youth, vitality, and creativity;
Aiding learning environment lighting reflection: Remains clearly visible even in low-light conditions.
Common fluorescent colors include yellow-green, orange-red, rose-red, and blue-violet. Yellow-green is the most commonly used in student stationery because it has the highest brightness and maintains stable performance under natural light.
-
Where can you buy Fluorescent pigments in bulk?
Fluorescent pigments emit bright, visible light under ultraviolet or other light sources and are widely used in various applications, including fluorescent coatings, stationery, textiles, plastics, advertising signage, and electronic displays. As a professional Daylight fluorescent pigment ingredients. supplier and manufacturer, Wanlong Chemical Co., LTD. has nearly 10 years of experience in supplying and exporting fluorescent pigment ingredients from China. You can confidently purchase fluorescent powder from Wanlong Chemical Co., LTD. If you have any questions or concerns, please feel free to contact us and we will get back to you within 1 business day.
If you have needs please contact us.
Established in 1989, Wanlong Chemical Co., LTD. has been focusing on polymer synthesis and fine chemical intermediates research and development and production for nearly 40 years, and has developed three business systems - polymer materials, organic dyes and chemical intermediates, including Fluorescent pigment powder. We offer wholesale prices for bulk purchases, even for small quantities, and offer a free sample to potential customers. If you have needs please contact us.
Post time: 2025-10-15 17:32:34
- Previous:
- Next: Can Caryon Wax be Used for Candles | Wanlong