月: 2022年12月

What Is an Ejector Pin?

An ejector pin is a mold component used to eject the finished product from the mold during the aluminum die-casting and resin parts molding process. It plays a crucial role in mold-based molding, where molten metal or resin is poured between two molds. The product is then removed after it has cooled and solidified, facilitated by the ejector pin.

Essentially, without the Ejector Pin, extracting the product from the mold would be impossible.

Uses of Ejector Pins

Ejector pins are indispensable in mold-based molding, catering to die-cast molding with metal molds, such as aluminum, magnesium alloys, and cast iron, and for injection molding of various resin parts. Available as standard products, ejector pins come in round and square shapes, with round pins typically used for products with shallow depths like lids. They should be installed near ribs or areas with high mold release resistance. Conversely, square pins are preferred for products with deeper bases to minimize the visibility of whitening, a common issue in resin extrusion.

Principles of Ejector Pins

The ejector pin operates by pushing out and detaching the molded product that adheres to the mold. Molds, usually split into fixed and movable parts, allow the material to be injected in between. Once the mold opens, the ejector pin, embedded in the movable mold, protrudes to separate the product. This pin is attached to the ejector plate of the molding machine, which when actuated by the ejector rod, pushes the pin out, leading to ejection of the product.

Structure of Ejector Pins

The architecture of a straight ejector pin encompasses a sliding part, a non-sliding part, and a collar. The sliding part requires high precision for smooth operation and to prevent defects like burrs. The non-sliding part, designed to mitigate stress concentration, may undergo treatments like annealing for enhanced durability. Modifications to prevent rotation and ensure the integrity of the molded product and the pin itself are also common, such as adding protrusions or altering the pin’s head shape.

1. Sliding Part

This component, fitting into the core’s mounting hole, must be precisely machined and have a smooth surface to minimize friction and prevent defects.

2. Non-Sliding Part

Located at the interface with the collar, this part is designed to absorb stress, with treatments applied to strengthen it against stress concentration. Depending on the product’s design, preventing the ejector Ppin’s rotation to avoid damage or deformation is often considered, using techniques like head modifications.

What Is Citric Acid?

Citric Acid is an organic acid found in citrus fruits and is a type of hydroxy acid with three carboxy groups (-COOH).

It is a clear colorless or white solid, and is available in two forms: anhydrous crystals containing no water molecules, and monohydrate with a single molecule of crystalline water. Both are odorless and have an acidic taste.

Citric Acid appears in the middle of the TCA circuit (citric acid circuit), which breaks down carbohydrates, fats, and proteins into energy substances, and performs important functions. It also has antibacterial properties and the ability to absorb calcium.

Uses of Citric Acid

Citric Acid is widely used in pharmaceutical, food, industrial, and cosmetic applications, depending on its purity.

1. Pharmaceutical Use

Citric Acid for pharmaceutical use is used as an ingredient in preparations for the purpose of buffering, correcting taste, and foaming.

2. Edible Citric Acid

Edible Citric Acid is added to a variety of foods as an acidulant that imparts a fruity sour taste and as a vitamin C stabilizer. It is also used as a dietary supplement to relieve fatigue, reduce muscle pain, increase appetite, and improve liver function.

Furthermore, citric acid is useful as a pH adjuster because of its acidic nature. By adjusting the pH of food, it can inhibit the growth of microorganisms and improve shelf life.

3. Industrial Use

Citric Acid for industrial use is used to clean calcium carbonate, which causes water stains, due to its property of absorbing calcium. It also neutralizes and removes alkaline stains, making it possible to dissolve and remove soap scum.

It is also used in bath salts and bath bombs. 

4. For Cosmetics

Citric Acid for cosmetics is used as a pH adjuster, pH buffer, and astringent, taking advantage of its acidic nature. The pH of the skin is slightly acidic (pH 4.5-6), and a change in pH causes skin irritation. pH adjusters can be added to products to maintain a slightly acidic pH.

Astringent action refers to the effect of tightening pores and inhibiting excessive secretion of sweat and sebum.

In addition to citric acid, other acidic substances commonly used are aluminum chloride, alum, and zinc sulfate.

Properties of Citric Acid

1. Physical Properties

Citric Acid is represented by the chemical formula C3H4 (OH) (COOH) 3, has a molecular weight of 192.13, and is a white, odorless crystal or crystalline powder.

It has a flash point of 100°C, a melting point of 153°C, no boiling point, a decomposition temperature of 175°C, an ignition point of 1010°C, and an explosive range of 1.9 vol/% lower and 4.8 vol/% upper. Its density is 1.665 g/cm3 and pH of 2% aqueous solution is about 2.0.

2. Chemical Properties

With a solubility of 59.2 g/100 g (at 20°C), it is extremely soluble in water and highly hygroscopic. It is also soluble in ethanol.

Although stable under normal handling conditions, it may react violently when in contact with strong oxidizing agents or strong alkaline agents. In addition, its aqueous solution is acidic, and thus has a high potential to corrode metals.

It decomposes at 175°C and converts to aconitic acid. If mixed with air at a certain rate in powder form, there is a risk of dust explosion.

Other Information on Citric Acid

1. Safety of Citric Acid

Citric Acid is a very safe compound, as it is used for both food and cosmetic applications. On the other hand, it is a strong eye irritant and can cause respiratory irritation if inhaled in large quantities, so care should be taken when handling it to avoid contact with the eyes and inhalation of large quantities.

2. Handling Citric Acid

When handling citric acid, wear protective gloves, protective clothing, protective glasses, and a protective mask, and work in a well-ventilated area. It is important to wash hands thoroughly after handling.

Keep the storage area clean to prevent product contamination, and store away from direct sunlight, high temperatures, and high humidity. Since the product is highly hygroscopic, the container should be sealed and stored in a dry place to avoid moisture absorption.

Avoid contact with strong oxidizing agents, strong alkaline agents, and metals, which are hazardous substances that can cause color mixing, and store in polyethylene, polypropylene, glass, etc.

What Is Methyl Formate?

Methyl Formate is an organic compound classified as a carboxylic acid ester with the molecular formula C2H4O2. It is also known as methyl methanoate, methyl metanoate, etc. It is known as the lowest molecular weight carboxylic ester in existence.

Methyl format has a CAS registration number of 107-31-3. It has a molecular weight of 60.05, a melting point of -100°C, and a boiling point of 32.5°C.

At room temperature, it is a volatile, colorless, transparent liquid. It has an ether-like sweet odor. Its density is 0.974 g/mL. It mixes freely with organic solvents such as benzene, acetone, and ether, and is approximately 20%~30% soluble in water at room temperature.

Uses of Methyl Formate

Methyl Formate is used as a synthetic raw material for basic chemicals, a fragrance, a solvent, a hardener in molds and cores, a foaming agent, a spraying agent, and a carbon monoxide generator.

As a raw material for the synthesis of basic chemicals, it is used in the industrial synthesis of formic acid, formamide, acetic acid, and DMF (N, N’-dimethylformamide). Its high vapor pressure is also used in some applications as a quick-drying agent.

Historically, it has also been used as a coolant by taking advantage of its decomposition reaction. Until safer coolants were developed, methyl formate was used to replace sulfur dioxide for refrigerator cooling.

In addition, applications exist where it is used as a non-electrolyte solvent in rechargeable batteries. When methyl formate is used as a non-electrolyte solvent mixed with a compound having acrylic groups, the increase in battery thickness during storage at high temperatures can be greatly reduced. Even when mixed with other electrolyte additives, it has been confirmed that the effects are not offset or reduced.

Methyl formate, along with ethyl formate, is a substance that is attracting attention as an electrolyte solvent for new high-performance rechargeable batteries.

Properties of Methyl Formate

1. Synthesis of Methyl Formate

The laboratory process for the synthesis of methyl formate is a condensation reaction of methanol and formic acid. In large scale synthesis, such as in factories, methyl formate is synthesized by the reaction of methanol and carbon monoxide in the presence of a strong base.

2.Chemical Properties of Methyl Formate

Methyl formate has a high vapor pressure (64 kPa at 20°C) and is easily volatile. It has a flash point of -19°C, making it highly flammable.

Although stable under normal handling temperatures and pressures, it may react with strong oxidizers, posing the risk of fire or explosion. When storing, avoid high temperatures and contact with strong oxidizers. 

3. Chemical Reactions of Methyl Formate

It is known that formamide can be synthesized by the chemical reaction of methyl formate and ammonia. The chemical reaction of methyl formate with dimethylamine yields DMF (N, N’-dimethylformamide).

Types of Methyl Formate

Methyl formate is sold mainly as a reagent product for research and development and as an industrial chemical product.

Reagent products for research and development are available in various volumes, such as 100 mL, 500 g, 500 mL, and 2 L. Normally, these reagents can be handled at room temperature.

Industrial chemical products are supplied in drums, pails, and other large factory-friendly packages, and are used for applications such as casting hardeners and CO sources.

Other Information on Methyl Formate

Methyl Formate Safety Information

Methyl formate is highly flammable as mentioned above. It is also known to cause mild skin irritation, strong eye irritation, damage to the central nervous system, damage to visual organs, and irritation to the respiratory tract in humans.

What Is Formic Acid?

Formic Acid is an organic acid with one carboxy group. It was first obtained by distillation of ants (Latin: formica, hence the name). It is also known as methanoic acid.

Formic Acid in high concentrations is toxic and corrosive to the skin, so it should be handled with care.

Uses of Formic Acid

Formic Acid is used in a wide range of fields, including dyeing, rubber, leather, medicine, fragrances, and chemistry.

Specific uses include the following:

• Preservatives and antibacterial agents in livestock feed
• Metal treatment
• Rubber latex coagulant
• Semiconductor cleaning agents
• Bleaching and dyeing auxiliaries for textiles
• For leather processing
• Lime scale removers and other cleaning products

Formic acid can also be used in the chemical industry as a raw material for formic acid compounds, formic acid polymers, solvents, synthetic resin catalysts, etc. For example, by esterifying formic acid, it is used in fragrances that impart fruit aromas, as well as in pharmaceuticals and agrochemicals.

Formic acid aqueous solution is also being attempted to be used as a fuel because of its excellent safety and environmental cyclicity, with no possibility of combustion or explosion.

Properties of Formic Acid

Formic Acid is a colorless liquid with a pungent odor. Its melting point is 8.40°C and boiling point is 100.75°C. It is soluble in many polar solvents and hydrocarbons as well as water. Aqueous solutions of formic acid are the most acidic of the monovalent aliphatic carboxylic acids.

As such, it is more strongly acidic than acetic acid. Formic acid, as a carboxylic acid, has unique properties. For example, it can react with alkenes to yield formic acid esters.

Formic acid decomposes upon heating to water and carbon monoxide. Oxidation produces carbonic acid.

Structure of Formic Acid

Formic Acid has a molar mass of 46.025. It has both carboxy and aldehyde groups in its molecule, making it both acidic and reducing. It exhibits few Fehling reactions, although silver mirror reactions due to its reducing nature do occur.

When dissolved in hydrocarbons or in gas, it forms carboxylic acid dimers by hydrogen bonding.

Other Information on Formic Acid

1. How to Synthesize Formic Acid

Formic Acid is industrially obtained by synthesizing sodium formic acid by the reaction of carbon monoxide and sodium hydroxide under high pressure and acidifying it with sulfuric acid.

To concentrate, the aqueous solution is first cooled strongly to precipitate crystals of formic acid. Separated in a rectifying column and distilled with the addition of propyl formic acid, the distillate can be divided into two layers. Distillation of the propyl formate layer yields pure formic acid.

2. Synthesis of Formic Acid with Methanol and Carbon Monoxide

Formic Acid can also be produced from carbon monoxide and methanol. First, the reaction of carbon monoxide and methanol in the presence of a strong base produces methyl formic acid.

Formic acid can then be obtained by hydrolysis of methyl formate. The reaction to produce methyl esters is industrially carried out under high-pressure liquid phase. Specifically, the reaction is carried out at 80°C and 40 atmospheres using sodium methoxide.

In addition, a large excess of water is required for efficient methyl ester hydrolysis. Therefore, hydrolysis via other compounds is also possible. For example, methyl formic Acid can be reacted with ammonia to produce formamide, which can then be hydrolyzed using sulfuric acid.

2. Related Compounds of Formic Acid

Formic Acid ionizes to form the formic acid ion (HCOO-). Salts containing the formic acid ion are called formic acid salts.

Formic acid can be dehydration-condensed with alcohol to yield formic acid ester (HCOOR). Some formic acid esters are components of fruit aromas. For example:

• Ethyl formic acid (HCOOC2H5) is a component of peach, amyl
• Formic Acid (HCOOC5H11) is a component of apple, and isoamyl
• Formic Acid (HCOOCH2C2CH(CH3)2) is a component of pear aroma.

What Is Quinine?

Quinine (chemical formula C₂₀H₂₄N₂O₂) is an alkaloid found in the bark of the cinchona tree, which is a tree native to Peru.

An alkaloid is a general term for basic, naturally occurring plant constituents that contain at least one nitrogen atom. Quinine is a diastereoisomer of quinidine.

It is an alkaloid that has been used as an antimalarial drug used since the 1600s. It is also effective in the treatment of filariasis and babesiosis. It has also long been used in the tropics to disinfect drinking water and to remove blue-green algae from drinking water.

Quinine has a bitter taste and fluoresces under ultraviolet light. It should be stored in a dark room because it reacts easily to light. The extracted compound exists as a white crystalline powder at room temperature.

Uses of Quinine

Quinine is used primarily as an antimalarial agent. Malaria is an infectious disease caused by a parasite of the genus Plasmodium called Plasmodium falciparum, which is transmitted to humans via mosquitoes.

Quinine is toxic to Plasmodium falciparum, and it prevents it from lysing red blood cells, thereby alleviating symptoms. It is also used to treat filariasis and babesiosis. It has antipyretic and analgesic properties and a direct effect on muscle membranes, and is often used in the pharmaceutical field as a remedy for common colds, nocturnal leg cramps, and myotonic disorders.

Quinine is also used as a bittering and flavoring agent due to its extremely bitter taste, for example, in the production of tonic water. The addition of quinine to drinking water has the effect of preventing the growth of microorganisms in addition to its palatability.

Disinfection of drinking water in tropical areas and removal of blue-green algae are also among its uses.

Properties of Quinine

Quinine is an alkaloid extracted from the bark of the cinchona tree, a member of the Rubiaceae family of plants.

It is a compound with molecular formula C₂₀H₂₄N₂O₂ and molecular weight 324.43 g/mol, and is a type of quinoline, a basic cyclic molecule. The structure of quinine is closely related to its bioactivity.

Based on the structure of quinine, artificial antimalarials such as chloroquine and mefloquine were later developed.

Quinine and other cinnamic alkaloids can be used as catalysts for stereoselective reactions in organic synthesis. It is also used as a fluorescent standard in photochemistry because of its constant fluorescence wavelength and high fluorescence quantum yield.

Its absorption wavelength peaks at around 350 nm and its fluorescence wavelength peaks at around 460 nm. The fluorescence at this time shows a bright blue color. Its fluorescence quantum yield is high in acidic solutions, and it shows high fluorescence of φ=0.58 in 0.1M sulfuric acid solution.

Other Information on Quinine

How Quinine Is Produced

Quinine is extracted from the bark of the cinchona tree, a natural product. There have been several reports on the production of quinine by chemical synthesis, but all of them are complicated processes and are inferior to isolation from natural resources in terms of economics.

In addition, the advantages of chemical synthesis of quinine for the treatment of malaria have been lost with the development of synthetic drugs (chloroquine, mefloquine, haloquine, etc.), which have a higher safety margin and can be mass-produced.

The extraction process from the plant is as follows:

1. The bark from a tree of the genus Cinchona is collected.
2. The bark is dried and crushed to a fine powder.
3. The bark is soaked in water or alcohol to extract quinine.
4. The extract is filtered and concentrated.
5. The concentrated liquid is chromatographed to purify the quinine.

What Is Xylene?

Xylene is an organic compound in which two hydrogen atoms of benzene are replaced by methyl groups.

It is also known as xylol, dimethylbenzene, and methyltoluene.

Uses of Xylene

Xylene has three isomers: p-Xylene, o-Xylene, and m-Xylene, which differ in the location where the methyl group is substituted. Mixed xylene, which is a mixture of these isomers before separation, is also used in industry. In addition to the three xylene isomers, mixed xylene contains a large amount of ethylbenzene.

Mixed xylene is used as a raw material for p-xylene, o-xylene, m-xylene, and ethylbenzene by isomer separation, and is also used as a solvent for paints, agricultural chemicals, and pharmaceuticals, as well as a solvent for cleaning fats and oils. Each isomer is also used as a raw material for synthesizing various chemicals, such as the following:

1. P-Xylene

Also known as 1,4-dimethylbenzene, p-Xylene is mainly used as a raw material for terephthalic acid and dimethyl terephthalic acid. Terephthalic acid and dimethyl terephthalate are raw materials for polyethylene terephthalate (PET). It is also used as a raw material for p-toluic acid.

2. O-Xylene

Also known as 1,2-dimethylbenzene, o-Xylene is mainly used as a raw material for phthalic anhydride. Phthalic anhydride is used as a raw material for plasticizers such as dioctyl phthalate and dibutyl phthalate, as well as for diallyl phthalate (DAP) and alkyd resins. It is also used as a raw material for o-phthalodinitrile, xylenol, and xylidine.

3. M-Xylene

Also known as 1,3-dimethylbenzene, m-Xylene is mainly used as a raw material for isophthalic acid. It is used as a raw material for polyester. It is also used as a raw material for meta-xylenediamine and Xylene resin.

Characteristics of Xylene

Like toluene, which is structurally similar to xylene, xylene is a clear, colorless liquid with a distinctive ink-like aroma.

When mass-produced industrially, it is extracted from modified petroleum oil, and has the characteristic of being highly flammable.
Xylene is also highly volatile and inhalation of its gaseous form has been reported to affect the nervous system. Thus, care must be taken when using it.

The three isomers p-Xylene, o-Xylene, and m-Xylene do not differ in appearance, odor, or hazardousness, but they have different physical properties due to differences in molecular structure. In particular, there is a significant difference in melting point, with p-Xylene at 13.3°C, o-Xylene at -25.2°C, and m-Xylene at -47.9°C. The boiling point of o-Xylene is 144.4°C, slightly higher than that of p-Xylene (138.4°C) and m-Xylene (139.1°C), although not as high as the melting point, so they can be separated and purified through distillation.

Other Information on Xylene

How Xylene Is Produced

The following methods are used to separate the three isomers p-Xylene, o-Xylene, and m-Xylene, and ethylbenzene from the industrial mixture of xylenes.

1. O-Xylene
o-Xylene is recovered from mixed xylene by distillation. o-Xylene is present in 20% of the mixed xylene, but can be separated by precision distillation due to the large difference in boiling points between o-Xylene and the other isomers. Ethylbenzene, a mixture of p-Xylene and m-Xylene, and o-Xylene can be separated by precision distillation. 

2. P-Xylene
A mixture of p-Xylene and m-Xylene after separation of ethylbenzene and o-Xylene from mixed Xylene is separated by a deep cold separation method. Since the difference in boiling points is within 1°C, separation by distillation is difficult, but the difference in melting points is approximately 60°C. Therefore, separation by deep cooling is possible. Therefore, separation is possible by deep cooling. However, the need to cool to ultra-low temperatures makes it energy inefficient, and p-Xylene has the disadvantage of low yield.

3. M-Xylene
After removing ethylbenzene, o-xylene, and p-xylene from the xylene mixture, m-Xylene is left over. However, the low yield of p-xylene by the deep cold separation method results in low purity. Therefore, an adduct that reacts selectively only with m-Xylene is formed and recovered. The recovered adduct is then decomposed with hydrogen to recover high-purity m-Xylene.

What Is a Flat Belt Pulley?

A flat belt pulley is a cylindrical component used in the transmission of rotational power through a flat belt. This type of pulley system allows for the transfer of rotational motion from an engine or motor to various mechanical parts, facilitating different rotational movements. Flat belts, characterized by their flat, rectangular cross-section, are praised for their simplicity and easy installation without needing to dismantle the pulley. 

Applications of Flat Belt Pulleys

Flat belt pulleys find utility in numerous applications:

1. Automobiles

Used in car engines to transfer power to components like air conditioner compressors and generators, enabling functionalities such as air conditioning and electricity generation.

2. Air Conditioning

Used in drive fans and compressors in HVAC systems, crucial for air circulation and temperature control in large commercial spaces and industrial settings.

3. Agricultural Machinery

Facilitate power transmission in lawnmowers from the engine to the blades, supporting efficient agricultural work through effective power delivery.

Principle of Flat Belt Pulleys

Made typically from steel or aluminum, flat belt pulleys may include flanges to prevent lateral belt movement, ensuring stability at high speeds. The design focuses on maximizing the contact angle between the belt and pulley for efficient power transmission, with a shaft hole to accommodate proper installation.

How to Choose a Flat Belt Pulley

Selection criteria include:

1. Material

Choose based on wear and corrosion resistance; steel for heavy loads and high speeds, aluminum for lightweight and corrosion resistance, and cast iron for wear resistance.

2. Dimensions

Consider diameter and width for tension, efficiency, and power transmission stability.

3. Installation Method

Ensure compatibility with the shaft and typically employ a keyway for installation.