What is plastic colorants?

plastic colorants is a general term for colorants used to knead colorants into plastics to color them (internal coloring). In addition to explaining what colorants are, their roles, functions, and types, we also explain how to manufacture masterbatches and mold plastics.

• Introduction
• Role and function of colorants
• Type of colorant
• masterbatches manufacturing process
• types of plastic
• Plastic molding method
• Features of our products

Introduction

There are various plastic products around us, such as plastic bottles, stationery, and food containers (trays). These plastic products are not originally colored. Plastic (resin) is essentially colorless (milky white). By adding colorants such as pigments, plastic products in a variety of colors are created.

There are two main ways to color plastic: external coloring and internal coloring. External coloring refers to coloring the surface of plastic, and includes printing, painting, plating, etc. On the other hand, internal coloring involves kneading coloring materials into the plastic to color it. Because the plastic and coloring material are mixed together, unlike external coloring, the interior is evenly colored. The coloring materials used for this internal coloring are collectively called "colorants."

Role and function of colorants

Coloring agents not only add color to our lives, but also help create product images, improve convenience, and improve quality. The easiest way to feel the effects of coloring is in decoration. For example, in cosmetics, home appliances, and automobile interiors, by adjusting the color and gloss to match the materials, we successfully create an impression of luxury and solidity.

Coloring also has the role of "identification". To take a familiar example, the lids of hot drink bottles are uniformly orange, so you can immediately recognize that the bottle is hot. In addition, to make it easier to identify during construction or emergencies, pipes for water use are color-coded as ``blue,'' and gas pipes as ``yellow,'' according to a global standard. In addition, color is also effectively used to protect the contents, such as by painting the outside of the product black to block UV rays and prevent the contents from deteriorating.

On the other hand, colorants not only provide color, but also have the role of directly improving the functionality of products. This is called a "functional colorant."
For example, the weather resistance (resistance to temperature changes and wind and rain) of automobile bumpers and containers is improved by using carbon black as a coloring agent.

It is also possible to add "conductivity" and "antistatic" functions to colorants. For example, in products that incorporate precision equipment such as IC chips, such as computers and testing equipment, even a weak current can cause malfunctions or breakdowns. However, the plastic material that protects them has the property of being easily charged with electricity, as evidenced by the fact that it attracts dust when the underlay is rubbed. In such cases, incorporating a highly conductive colorant into the plastic allows electricity to escape to the outside, reducing the risk of failure. Other applications include using white colorants on the backsheets of solar cells to reflect light internally and increase power generation efficiency.

Type of colorant

The main types of colorants include `` masterbatches,'' ``colored pellets/colored compounds,'' ``dry colors,'' and ``paste colors/liquid masterbatches.'' Plastic products are made by mixing these with natural pellets (plastic in the form of particles before mixing with coloring materials) and molding them.

masterbatches

A coloring agent in the form of pellets (particles). Highly concentrated pigments are kneaded inside, and you can easily change the shade of the color by adjusting the amount mixed with the natural pellets. It has excellent dispersibility, allows for uniform and beautiful coloring, and is easy to handle without worrying about scattering or contaminating equipment. It also has superior cost performance compared to colored pellets.

Colored pellets/colored compounds

Colorant in pellet form. Unlike masterbatches, it is already set to the same concentration (color) as the final product, so there is no need to mix it with natural pellets. It has the advantage of eliminating the hassle of compounding and making it easier to consistently produce the desired color, but it requires a large amount of inventory to make the product, making it more expensive than others.

dry color

Powdered colorant. It is made by mixing pigments and metal soap. It is the cheapest colorant because it requires little effort to manufacture, but it has some drawbacks in terms of handling, such as being easily splattered, easily staining equipment, and difficult to measure.

Paste color liquid masterbatches

Powdered colorant. It is made by mixing pigments and metal soap. It is the cheapest colorant because it requires little effort to manufacture, but it has some drawbacks in terms of handling, such as being easily splattered, easily staining equipment, and difficult to measure.

masterbatches manufacturing process

Currently, the main coloring agents used in Japan are masterbatches, which have excellent total balance and can be manufactured using relatively light equipment. masterbatches can be created with various colors and functions by incorporating pigments and other coloring materials and functional materials into the base pellets (resin material).

①Preparation/stirring

The raw materials, such as base resins, pigments, coloring materials, and functional materials, are weighed according to the designed recipe, placed in a stirrer, and mixed until uniform.

②Extrusion

The mixture is put into an extruder and melted and kneaded.
From the tip of the extruder, colored resin comes out in the form of long, thin rods like spaghetti.

③ Cooling

The extruded rod-shaped colored resin is placed in a water tank to cool and harden.

④ Cutting

Using a pelletizer, cut into pellets of approximately 3 to 5 mm to create masterbatches.

⑤Filling/packing

The completed masterbatches is packed into bags and stacked on pallets using a robot arm, ready for shipment.

types of plastic

There are many different types of plastics that can be mixed with colorants. Thermoplastic plastics (made by melting and molding with heat), which are often used in everyday items, can be classified into two categories: "crystalline" and "amorphous", each of which has various physical properties. When designing products, the physical properties of these plastic materials must be considered.
For example, among crystalline plastics, polyethylene (PE), which is resistant to heat and chemicals, is used for films and buckets, while polyethylene terephthalate (PET), which is highly transparent and durable, is used for things such as plastic bottles and egg cartons.

Plastic molding method

There are many ways to mold plastics, including compression molding, injection molding, calendar molding, extrusion molding, blow molding, and vacuum molding.

injection molding

Molten resin is poured into a mold as if injected with a syringe. It is used to make containers and caps.

extrusion molding

A screw inside the machine is rotated to push the melted resin forward and form it. It is used to make tubes and pipes.

blow molding

Compressed air is blown into the inside of the melted resin and molded to fit the shape of the mold. It is used to make bottles, droppers, etc.

calendar molding

The resin is kneaded with heated rolls and stretched to form it. It is used to make films, sheets, etc.

compression molding

The resin is placed in a mold and molded by applying pressure while melting it with heat. It is mainly used to make containers.

vacuum forming

After heating the plate-shaped resin to make it soft, it is vacuum-suctioned and molded to fit the shape of the mold. It is used to make containers.

Features of our products

TOYOCOLOR 's plastic colorants come in a variety of forms, including powder, paste, and pellet forms, depending on the type of plastic and molding method. We also provide solutions tailored to the type of plastic used by the customer and the shape of the colorant desired.
Furthermore, we also manufacture high-performance compounds and masterbatches that go beyond simple coloring applications and have properties such as flame retardancy, conductivity, and optical properties.