Dhristi JEE 2022-24

Urea Formaldehyde Resin

Urea Formaldehyde or urea methanal is a type of opaque thermosetting resin or polymer obtained as a result of the chemical reaction between urea and formaldehyde. Urea is a solid crystal obtained from ammonia, and formaldehyde is a highly reactive gas obtained from methane. Both chemicals react to form the urea formaldehyde polymer, in which formaldehyde acts as the crosslinker. The resins formed by the chemical composition of urea and formaldehyde are used in adhesives, plastics, particleboard, and moulded objects. The Urea-formaldehyde productions are nearly 20 million metric tonnes annually worldwide, and this is almost 80% of all the amino resins produced worldwide.

History & Synthesis of Urea-Formaldehyde 

Urea formaldehyde resins are primarily made up of formaldehyde and urea, and these resins are formed in water with a pH level of 7 or above. In industries, urea resins are prepared by condensing urea and formaldehyde in an aqueous solution, and in this reaction, ammonia is used as a catalyst. 

The Urea-formaldehyde was first produced in the year 1884 by Holzer. The first Urea formaldehyde resin plastics were introduced in the year 1896, and the patents for this thermosetting resin were first given to German and British chemists in the early 1920s. Later, in 1925, the British Industrial Plastics Ltd. came up with a more durable and lightweight urea resin called the Beetleware. 

Around the 1950s, urea-formaldehyde was replaced by melamine urea formaldehyde, which was more durable. Later, melamine urea formaldehyde resin was used in moulded products for its more extended durability. Today, melamine urea formaldehyde resin is used in the production of wood panels to make the hold more solid and firm. 

Urea Formaldehyde Uses

The uses of urea formaldehyde resin are many, and it is used extensively in industrial products and even in home decor products. In general urea formaldehyde products include decorative laminates, textiles, paper, sand moulds, wrinkle-resistant fabrics, cotton blends, etc. It is extensively used as an industrial adhesive and in wood glue. In the early years, it was used in the production of electrical appliances casing, such as desk lamps. It acts as an insulator and prevents electric shocks. It is also used in foams for creating artificial snow in movies. 

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In the agricultural field, urea-formaldehyde is used as a rich source of nitrogen. The microbes found in the soil act on the urea-formaldehyde to decompose it into liquid nitrogen for the use of the plants. However, the action of microorganisms and the release of nitrogen depends on the temperature.

In its pure state, urea-formaldehyde can be strengthened using cellulose and can be tinted using a number of pigments to produce light, rigid, translucent, and colourful kitchen and home decor equipment. 

In the cosmetics industry, urea-formaldehyde resin is used to make containers for storing cosmetic products due to its high resistance to chemicals. It is also used in many electrical appliances such as switchboards and wall outlets due to its high electrical resistance. 

The urea formaldehyde polymer lacks the resistance to moisture, and therefore urea formaldehyde adhesive is used in the production of many wood products that are used for interior decorations only. 

Health Hazards of Urea Formaldehyde

There are no health hazards of urea-formaldehyde unless formaldehyde is released from Urea-formaldehyde resins. When formaldehyde is released into the air with a concentration of more than 3.0-5.0 ppm, its effects on health are significant. High exposure to formaldehyde can increase the risk of cancer. When the concentration of formaldehyde begins to increase in air, it causes serious health hazards, such as watery eyes, irritation in the nose, cough, skin rashes, allergic reactions, burning sensation in the throat, nausea, and in some cases, it can even cause difficulty in breathing. 

FAQs on Urea-Formaldehyde

1. What is Urea Formaldehyde? How is it Synthesised?

Answer: Urea-formaldehyde is a nontransparent, thermosetting, and elastic material that is obtained from a chemical reaction between urea and formaldehyde. The properties of urea-formaldehyde include high elasticity, high heat-distortion temperature, low water absorption, and high surface hardness. The refractive index of urea-formaldehyde is 1.55. It is produced worldwide, and its production is approximately 20 million metric tonnes annually. It produces totals to almost 80% of the other amino resins produced in the world. 

The primary compositions of urea-formaldehyde are urea (a solid crystal obtained from ammonia) and Formaldehyde, a highly reactive gas obtained from methane. In the industrial production unit, the urea-formaldehyde resin is synthesised by condensing urea and formaldehyde in an aqueous solution. 

2. Mention Some Uses of Urea Formaldehyde Resin.

Answer: Urea formaldehyde uses are extensive in the wood industry, plastic industry and agricultural field. It is mainly used as an adhesive in the production of wooden products for its low water absorption property. The products that are manufactured using formaldehyde resin include decorative laminates, textiles, paper, sand moulds, wrinkle-resistant fabrics, cotton blends, etc.

Urea-formaldehyde being a rich source of nitrogen is used in the agricultural field. It releases nitrogen on the action of microorganisms in the soil and promotes the growth of the plants. The urea-formaldehyde is resistant to many chemical compounds, which is why it is used in the production of jars and containers to store cosmetics. Due to its high resistance to electricity, it is used in many electrical appliances, including switch birds, switches etc.