Requirements and production processes for raw materials for impregnated paper veneer plywood and shuttering plywood

Author: Peng Limin

Setting: Plywood Industry Research Institute, CAF

Source: China Wood-based Panel, No. 5, 2018

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This paper introduces the raw material requirement, production process and hot pressing process of plywood and joinery board with impregnated film paper veneer at present in China, and analyzes the causes of product defects.

Impregnated paper veneer plywood and joinery board (commonly known as ecological board in the market) are a new type of decorative board developed on the basis of impregnated paper veneer wood-based board.
Around 2005, according to the raw materials and processing technology of wood-based panel with impregnated film paper veneer formwork plywood for sale, domestic enterprises have formed a kind of panel with plywood and joinery board as the base material and impregnated film paper tego film plywood as the veneer material through innovation and improvement.
This product has high dimensional stability, good decorative and environmental protection, so it is more and more popular with consumers, but also promote the impregnated film faced birch plywood and joinery board industry to mature and grow.
Although the ecological board market has developed well and the product types are abundant at the present stage, compared with the traditional artificial board, the development time is relatively short and the product quality is uneven.

Wood Industry Research Institute of Chinese Academy of Forestry, together with relevant domestic testing institutions and representative enterprises of impregnated construction plywood sheets and shuttering plywood sheets, has formulated GB/T 34722 — 2017 “Impregnated best quality shuttering plywood and Joinery Board”, which will be implemented on May 1, 2018.
The author in the process of developing standards, after a long period of factory and market research, found that the ecological quality of plate is more or less defects, now on the induction and summary, and put forward some requirements of base material and production technology, in order to ecological board production enterprises and consumers play a guiding role, to meet the requirements of national standards and the needs of the consumers,promote the healthy and sustainable development of the product.

Requirements for raw materials for impregnated 12mm black film faced plywood and phenol film 12mm.

The composition of impregnated shuttering ply 12mm price and film faced18mm shuttering ply b&q mainly includes multilayer plywood or concrete form plywood suppliers base material, thin sheet (veneer, science and technology wood) and impregnated veneer paper.

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1.1 Requirements of substrate

Plywood and joinery board base materials should meet the requirements of GB/T 9846 — 2015 “Common Plywood” and GB/T 5849 — 2006 “Joinery Board” respectively. Attention should be paid to the following aspects:

1) The thickness of the substrate should be uniform, the board surface is smooth and clean, otherwise sanding treatment;

2) The appearance quality of both sides of the base material shall meet the requirements of GB/T 9846-2015 Grade I, and the adhesive strength shall meet the requirements of class ⅱ plywood;

3) The moisture content of the base material is an important index. The low moisture content of the base material leads to the decline of the surface bonding strength of the impregnated paper veneer plywood and joinery board and other defects such as dry flowers;
The moisture content of the substrate is too high, which is prone to bubble, stratification, wet flowers and other defects during hot pressing, so the moisture content should be controlled at 6% ~ 16%;

4) The substrate surface as far as possible is the whole veneer, such as the use of the board is required to tight joints, otherwise the joint defects will be reflected in the shuttering ply board price and suraksha shuttering ply.

1.2 Requirements for thin plates

The thin plate is covered between the base material and the impregnated white film faced plywood to some extent to conceal defects.
Generally including greenply shuttering plywood, recombination decorative veneer (commonly known as science and b&q shuttering ply).
Thin plate requirements: 1) uniform thickness;
2) The surface is basically defect-free and the color is basically consistent;
3) The whole sheet has no seam;
4) Moisture content of 6% ~ 16%.

1.3 Requirements for impregnated film paper

Generally speaking, most manufacturers consider the business and use of impregnated film paper, using two impregnation method, that is, decorative paper impregnated urea formaldehyde resin for the first time, via drying, and then surface coating melamine resin glue.

The physical and chemical properties of impregnated paper, such as volatile content, precuring degree and formaldehyde release, directly affect the quality of ecological board.
The content of volatile matter in impregnated paper is low, and it is easy to produce dry flowers.
Lack of impregnation, 12mm shuttering ply wickes easy to produce surface pores and poor wear resistance;
The volatile content of impregnated paper is high, and 9mm shuttering ply it is easy to produce uneven surface gloss.
The fluidity of the impregnated film paper glue is poor, the sealing property of the glue is not good, and it is easy to cause poor surface pollution resistance and poor surface water vapor resistance with price of shuttering plywood.

Production process of impregnated shuttering plywood for sale and black shuttering plywood

2.1 Production process of direct paste veneer

Direct stick method veneer

Impregnated film paper + thin plate + joinery board/plywood base material, namely “one time coating method”, ply construction the production process is shown in Figure 1:

2.2 Production process of repasting veneer

The impregnated adhesive paper is first hot-pressed with the thin plate, and then pressed on both sides of the base material, namely “secondary laminating method”. The production process is shown in Figure 2:

Repasting method veneer production process

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