To comply with conservation policies, makers are adopting engineered wood and nontoxic finishes in production.

Qunsheng of China offers the QS-N07 model, an interior door made of HDF and coated with PVC film. The core material is honeycomb paper.

China and India suppliers of interior doors consider the growing environmental awareness an important factor in material selection.

Engineered wood, which consists of a platform, core and wear layer, is gradually replacing solid wood in manufacture. This is becoming a popular choice as companies strive to support reforestation and sustainability efforts in both the domestic and overseas markets.

With this composite, only the uppermost segment is made of virgin material. The rest comes in a combination of wood scrap, cellulose-based fiber fillers such as palm leaves and stems, and recycled plastic.

Such a composition is deemed environment-friendly because it reduces wood consumption significantly. A piece of lumber, for instance, can yield five or six wear layers for engineered wood as opposed to a single plank when used in solid wood construction.

Moreover, several surface treatments applied on the composite provide protection against humidity and moisture. This, in turn, prevents warping and cracking, conditions to which solid wood is prone.

In China, interior door suppliers employ an amalgam of wood veneer and wastes, rubberwood, honeycomb paper, fire-retardant plastic, and MDF or HDF. As a result, the use of virgin materials has decreased by 10 to 40 percent.

Another environment-protection measure is the adoption of less-hazardous substances for the finishes. Plant-based paint that does not contain volatile organic compounds and PVC are among the preferences.

Some makers are still using formaldehyde, albeit with a weaker concentration to reduce the toxicity level.

One China-based company interviewed for this report is only applying 0.1mg/L of the substance, which is even lower than the recommended amount of 1.5mg/L.

India suppliers, on the other hand, are adopting the compound as a binding agent for engineered wood’s multiple layers. Specifically, phenol and melamine urea formaldehyde resins that comply with the IS 848-1974 standard are being utilized.

A growing number of India makers are launching interior doors that are made of composites, although the majority of output still comes in seasoned solid wood. The latest releases include versions in pressed wood, prelaminated plywood, HDF, MDF and particleboard.

China’s aesthetic improvements

China suppliers are enhancing the visual appeal of their engineered wood interior doors.

Assa Abloy-Wangli Security Products Co. Ltd is using the thermal transfer overprinting technique to create different wood-grain patterns on its rubberwood and MDF models. Products bear the CE mark and conform to HJ/T303-2006 and GB17565-1998 directives.

Assa Abloy-Wangli is among China’s certified environment-friendly interior door manufacturers, which are classified by the government’s State Environmental Protection Administration.

Shenyang Tianchuang Baolao Door Co. Ltd is also adopting heat transfer technology for surface embellishments. It recently acquired additional automatic equipment for the process.

Shenyang Tianchuang Baolao procures macromolecule plastic and wood scraps locally.

At Zhaoqing Tianjiang Doors Co. Ltd, computerized carving machines are being employed to render 3-D designs on the wear layer. Models are then coated with PVC film for scratch resistance.

The company sources wood veneer and PVC from Germany and Japan, and HDF from Jixiang of Guangdong province.

Qunsheng Security Door Co. Ltd’s new HDF interior doors feature computer or handcarved images.

To ensure safety, the supplier sends products to the China National Accreditation Committee for volatile organic compound and formaldehyde content testing.

ISO 9001:2000-certified Zhongshan Oujili Doors Industrial Co. Ltd utilizes South Korea- and Germany-made paint in rendering woodlike textures on designs.

Guangzhou Fuhua Aluminum Plastic Interior Door Co. Ltd offers the K008 model, which has sandblasted glass panels with images depicting swimming fish. The version is fitted with an AlMg frame covered with walnut veneer.

India’s solid wood models

The DP-425 model from India’s D.P. Woodtech is a French door with a self-molded frame. Priced at $375, the 7x3ft and 35mm-thick product comes in mango wood.

Most India companies still prefer seasoned solid wood, particularly for high-end interior doors.

Mango timber is widely used in manufacture because of its low cost and abundant supply, although spruce, teak, shisham, marandi, cedar, oak, maple and mahogany are also being adopted. These types of wood are derived from trees that are at least 80 years old. Chemically treated, designs in these materials can last more than 25 years.

D.P. Woodtech (P) Ltd’s recent releases include the DP-153 model, an interior door made of Ivory Coast teak. Priced at $6,250, the 9x6ft and 35mm-thick product features a handcarved pattern on the surface.

D.S. Woodtech Ltd has introduced the model DS-731 shisham interior door with a natural gloss coating. The double-leaf version goes for $28 per square foot.

D.S. Doors (P) Ltd has launched a main entrance Burma teak door featuring a carved design in Rajasthani style. The wood is chemically treated using vacuum and pressure systems. The price is $45 per square foot.

Megha Doors Inc. is among several India makers that offer versions in engineered wood. It adopts virgin materials for the frame, and plywood and MDF board for the leaf. Phenol formaldehyde resin is used for binding the various layers.

Models can withstand termite and fungal attacks. Prices are between $2 and $3.50 per square foot.

India suppliers conduct QC in-house with help from the Dehradun Forest Research Institute.