Wood plastic material is a new type of composite material developed in recent years, light weight, rigidity, acid and alkali resistance, waterproof and insect resistant, environmental protection, it can be nailed, drilling, planing, sawing, gluing and painting like wood, but also like thermoplastic molding processing and surface decoration printing, is currently widely used in building materials, municipal facilities, packaging materials and other fields. In addition to the above advantages, its feel is very similar to wood, so it is determined that the application in the field of furniture has great development potential. However, at present, the application of wood-plastic materials in the furniture industry is not much, what is the reason for this phenomenon? This paper discusses this problem from the two aspects of material characteristics and consumers.

First, wood-plastic materials in the furniture industry application limit factors

1. Production mode

At present, the production of wood-plastic materials mainly adopts extrusion molding, that is, the mixture of wood powder and molten plastic after extrusion die holes to obtain various profiles and plates, and the growth rate of profiles is much higher than that of plates. In order to reduce the amount of raw materials, enterprises mostly use micro-foaming technology to reduce the density of materials and produce small through holes in profiles through mold technology. The surface can be decorated and protected by spray painting or ink printing technology, in which the printing technology can not only obtain a very realistic wood and stone texture, but also because the ink penetrates into the inside of the material, the surface scratch within a certain range will not have a greater impact on the appearance. The production method of wood-plastic materials has a lower limit system for furniture design and manufacturing:

(1) Low freedom of modeling

Because it is extrusion molding, wood-plastic materials can only show a straight line in most cases, almost no curve shape and smooth turn, so it is difficult to reflect the affinity and comfort that furniture should have, and the freedom of design for furniture production is greatly reduced. From the current situation, the production method that can be used to develop furniture products with wood-plastic materials is closer to panel furniture, and the appearance is also very similar, but the cost is slightly higher and the market competitiveness is weak. Therefore, if the appearance can not have the main characteristics of solid wood furniture, the development of wood-plastic furniture will be subject to great market resistance.

(2) High requirements for end processing

The through hole of the profile can reduce the weight and save the material, which is the main reason for the low use cost of wood-plastic materials. However, the strength of the end part of the profile is low, vulnerable to collision or local force damage, and the stress node of the furniture is often at the end of the material, so it is necessary to carry out special treatment on the end to increase the strength, improve the cost and technical difficulty; In addition, consumers have higher requirements for details when appreciating furniture, requiring end treatment not only to consider the force, but also to consider the beauty and change of the form, the cleanliness and comfort requirements of the use process, which bring difficulties to the use of wood-plastic materials in the field of furniture.

(3) Limited connection modes

At present, the commonly used bonding method of wood-plastic materials is through the groove clamping, nailing and bonding. The groove splice can limit the activity of two dimensions between the materials very well, and the structure is reliable, but the use is limited to the joint of the surface, and it is difficult to be used as a support structure; Nailing requires sufficient reaming depth, generally need to fill the hollow profile inside the wood block, low production efficiency; Bonding has high requirements on the contact surface, and the production is difficult to achieve automation, and the glue may flow to the surface and affect the appearance.

2. Surface quality

(1) Surface flatness is an important factor in the quality of furniture, whether solid wood furniture or panel furniture are very demanding, for wood-plastic materials, this requirement is particularly harsh. Wood-plastic materials will be extruded from the mold hole due to internal stress will produce local deformation, although the change of environmental humidity has little effect on the wood-plastic materials, but the large temperature difference will lead to the warping deformation of flat sheet. At present, the problem encountered in the export of office partitions made of wood-plastic materials is the deformation of products caused by the temperature difference between the origin and the exporting country.

(2) The low surface hardness of wood-plastic materials is also a disadvantage affecting its application in the furniture industry. Furniture in the installation, transportation and use process may be subjected to a variety of collisions, if the surface hardness of the furniture is low, it is easy to produce surface loss. The surface of the wood-plastic profile can be marked with keys or even fingernails, although the printed wood grain can play a disguise role, but as a furniture material, after all, it is a big deficiency.

(3) The surface texture of the material with a printed finish is regularly repeated by the diameter limitation of the printing roller wheel, which affects its realism when used in a large area. Some wood such as beech texture is dotted distribution, there is no large patterned texture, repeated will not have obvious traces of artificial, while rosewood, acid branch wood has obvious linear texture, the same texture after repeated feeling very unnatural.

3. Consumption value concept

Now most consumers think that solid wood furniture is better than panel furniture, on the one hand, because the large-scale mechanized production of panel furniture makes its cost decline, the market price is far lower than solid wood furniture, on the other hand, due to the forest resources crisis caused by people's value judgment on wood, solid wood furniture value is growing. In addition, some enterprises in order to improve their market value, the precious wood and can master the extraordinary carving skills combined to produce several sets of town store treasure, mark hundreds of thousands of sky-high prices, to guide the value judgment of consumers. In contrast, the value of artificial panels such as density boards and plywood is obviously low, which determines that wood-plastic furniture is difficult to squeeze into the furniture market with a larger profit margin. Without large profits, it is difficult for new materials to enter the market.

Second, the proposal of countermeasures

1. The use of secondary processing technology and suitable plastic, hardware design to make up for the lack of production technology.

(1) The bending test of wood-plastic profiles proves that the single linear style of wood-plastic profiles can be changed, and curve modeling and bending can appear on wood-plastic furniture. The test method and process are as follows:

According to the data of the pilot enterprise and the preliminary test, it is determined that the deformation temperature range is about 155 degrees, and the method of filling hot sand in the mold is determined by referring to the metal bending process and the preliminary test. Determine the bending radius and Angle range according to the design objective; The optimum deformation temperature was determined according to the pre-stage test. Adjust the bending technique according to the results of each test; Conclusions are drawn from the analysis of test records.

A total of 39 profiles were bent in this test, 37 of which were of record value (photos of some test samples are attached). It is concluded that the best deformation temperature of solid material is about 155 degrees Celsius. The deformation temperature of the hollow material is about 162 degrees Celsius; The limit of small bending radius at 90 degree Angle: JF11020 is 20mm, JF7040 is 40mm; Small bending radius at a 45 degree Angle: JF11020 is 31mm. According to the experimental results, the problems of freedom and Angle of molding used in furniture design and production can be solved, and the bending process is conducive to producing modeling characteristics.

(2) Foam molding technology is a pilot enterprise has been mature use of production technology, currently used in the manufacture of wood-plastic door, the basic principle is in the middle of two wood-plastic board filled with blowing agent, the use of blowing agent generated heat and pressure to make wood-plastic board pressed in the mold surface tensile deformation, after cooling naturally bonded to the whole door. The door panel produced in this way can be embedded in the hinge, handle, cushion wood and circuit and lock pipeline, high production efficiency, low cost, with the appearance of solid wood door quality.

With a little improvement, this technology can be used to produce embedded furniture door panels, panels, overall backrest chairs and other components, which are not only low cost, high efficiency, easy to install, but also can use molds to get different relief patterns, so that the choice of furniture modeling and surface decoration forms is more.

(3) With the help of special hardware and plastic parts to solve the sealing and connecting problems of wood-plastic profiles. Usually aluminum alloy profile products are closed by coloring or electroplating plastic fasteners, wood-plastic profiles can not only learn from this method, but also use the elasticity of the material to combine the fasteners and profiles more closely, so as to play a more overall visual effect. A good example is the installation of wood plastic decorative velvet: there is a nail slot with a seal on the decorative money, and the seal is stuck on the slot after the decorative line is fixed with a nail, so that the nail hole will not affect the appearance.

Wood-plastic parts special coupling design to consider the following factors: wood-plastic profile hole size is not accurate aluminum alloy profile, the coupling should have greater adaptability; The strength of thin wall is smaller than that of metal materials, and the fixing of hardware and wood-plastic profiles should have a large enough contact area; Use the internal cavity space of the profile to install subtle mechanisms to achieve some special functions; The foam technology can be used to bury the hardware inside the profile.

2. Improve surface quality by means of design

(1) Light deformation of the material will affect the appearance of the furniture, heavy will affect the use of furniture, whether solid wood furniture or panel furniture are facing this problem. At present, the method of paint or veneer is usually used to maintain the stability of the internal moisture content of the material to prevent deformation, or to cover up the deformation and play a decorative role in the larger area of the furniture parts with color or engraving patterns. Because the main reason for the deformation of wood-plastic materials is the temperature change, it is useless to isolate the method with paint, which makes the surface decoration design become a very important work. In addition to the common surface decoration techniques such as carving, Mosaic, segmentation, texture change, wood-plastic materials also have their own unique decorative techniques, such as printing, splicing, molding, and so on.

(2) The surface hardness of wood-plastic materials can be improved by coating high hardness paint layer, some companies have developed wood-plastic flooring, although its hardness can not be compared with reinforced composite flooring, but used as a furniture surface is not a problem.

(3) By increasing the diameter of the printing roller wheel to solve the repetitive cost of the surface texture is high but the effect is limited, you can consider replacing the existing roller printing method with an inkjet printer. At present, the inkjet printing machine produced by Agfa company in Germany can print large-format posters, billboards and signboards, and the surface quality of wood-plastic panels can be greatly improved through technical improvement and imitation to adapt to the surface printing of sheets.

3. Select the right product development direction

According to the traditional standard, wood-plastic materials can be drawn a conclusion that the wood-plastic furniture in the high quality of solid wood furniture and the low price of panel furniture is difficult to occupy a place in the living room and bedroom, but the excellent waterproof performance of wood-plastic materials determines its unique use value. The trend of bathroom decoration and the high price of the whole kitchen provide an opportunity for wood-plastic materials to enter the furniture market, and the breakthrough in the development of bathroom furniture for wood-plastic furniture is a shortcut for consumers to understand and accept wood-plastic materials.

Outdoor furniture has high requirements for the weather resistance of materials, and wood-plastic materials can meet this requirement. The ultraviolet rays in the sun accelerate the aging of most plastic products, but the wood powder in the wood-plastic material can effectively block the ultraviolet rays into the inside of the material, so that the wood-plastic material can be used outdoors for a longer time. From the analysis of economic factors, the production cost and maintenance cost of wood plastic materials are lower than that of wood and metal materials, so it is very promising to develop outdoor furniture with it.

Iii. Conclusion

Before the pinhole injection molding technology of wood-plastic materials is mature, the secondary processing technology is an effective means to solve the modeling and structural problems of single and small batch furniture, and the foam filling molding technology can be used for mass production of decorative parts with a more complex appearance or embedded connectors to produce components of composite furniture. Through the design of special hardware and plastic parts, the sealing and connecting problems of profiles can be solved; The surface quality of the sheet can be improved by using molding, high hardness paint and inkjet printing technology. It is important to choose the direction of product development, bathroom furniture, cabinets and garden furniture is a breakthrough for wood-plastic materials to enter the furniture market.