What are D2, D3, D4 Adhesives?
Within our large range of Adhesives, many have a ‘D’ grading, but what does it all mean?
If you are new to using PU adhesives, you may be wondering why they have a D in their title. You might be asking just how a D4 PU adhesive is any different to a D3 or D2 adhesive? It might be easy to tell a Tytex 1 kg 30 Min Set PU Adhesive from a Tytex 1 kg D4 PVA Adhesive. However, the D grade stands for durability and is part of the European standard BS EN 204 which governs the classification of wood glues for non-structural applications, and it helps to show how resistant the adhesive is to water. There are four durability gradings specified, so let us look at D1 through D4 adhesives.
Durability Classes:
D1 Adhesives:
D1 adhesives are the lowest in terms of durability. These adhesives work in interior areas in which the temperature rarely exceeds 50C. In addition, you can use them on wood with a moisture content up to 15%. They have a storage life of up to seven days in standard room temperatures and humidity. They have a required bond strength of less than 10 N/mm2, and you should use them for external wood bonding.
D2 Adhesives
The next step up on the durability scale are D2 adhesives. Like D1 adhesives, you should only use D2 glues for indoor work. These adhesives can cope with occasional short term exposure to water or moisture and temporary high humidity. However, the moisture content of the wood must not exceed 18%. D2 has a seven-day shelf life in normal conditions and has a required bond strength of less than 10 N/mm2. If submerged in cold water for three hours and stored for a further seven days, however, D2 has a required bond strength of less than 8 N/mm2.
D3 Adhesives
D3 adhesives are considered to be water-resistant. You can use them in interior areas where there is frequent short term exposure to water or moisture and frequent high humidity. Unlike the previous grades of adhesives, you can use D3 outdoors in areas not exposed to the weather. In normal conditions, D3 has a seven-day shelf life with a required bond strength of less than 10 N/mm2. If stored in cold water for four days, it will have a required bond strength of less than 2 N/mm2. After a further seven days of storage, the required bond strength increases to less than 8 N/mm2.
D4 Adhesives
D4 PU adhesives are often considered to be waterproof. You can use D4 PU adhesives in interior areas where there is frequent long term exposure to water or moisture. You can also use D4 PU adhesives in exterior areas exposed to weather, so long as you apply an adequate surface coating. In normal conditions, D4 PU adhesives have a seven-day shelf life with a required bond strength of less than 10 N/mm2. If you store it in cold water for four days, the required bond strength reduces to less than 4 N/mm2. This required bond strength can be maintained if placed in boiling water for six hours, then cold water for two.
Example of what each grade is used for:
D2:Â Furniture and woodworking. Manufacturing sofa frames in-line.
D3:Â High quality joinery, furniture making and veneering including flat panel lamination with plastic laminates.
D4:Â Bespoke furniture. High quality joinery, including windows, doors etc. in extreme situations. Timber frame applications including the bonding of chipboard flooring.
Now you understand the difference, you can find the right product for your application. Check out below, some of our ‘D’ grade Adhesives.
Example of D Grade Adhesives:
D2 Products:
Timbond Fast Drying D2 Adhesive 28kg
Tytex General Purpose D2 PVA Adhesive 25kg
D3 Products:
Professional Water Resistant PVA- Timbond D3 PVA
D4 Products:
Tytex Frame & Floor D4 PU Adhesive 1kg
Tytex Rapid 5 Min D4 PU Adhesive 1kg or 310ml
Tytex Standard 30 Min D4 PU 1kg or 310ml
Timbond Professional Waterproof D4 PVA
To find out more about our range of adhesives, including Tytex 1 kg 30 Min Set PU Adhesive and Tytex 1 kg D4 PVA Adhesive, we invite you to view our range online today. If you need some advice on our Adhesives, contact our technical team by email, phone or live chat.
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