Advantages with us,
1, Free sample is available for you to check product quality
2, Free setup cost for new case>1000 pcs
3, Quality is our number one priority
4, Great After-sale services
Goggle Case,Durable Goggle Case,Ski Goggle Case,Snowboard Goggle Case Dongguan Topreal bag&case., Ltd. , https://www.toprealcase.com
In the early days of human use of wood, it was found that the part of the log that was to be buried in the soil was surface-fired and then buried in the soil, and the use time of the log was significantly increased. The early use of preservatives is applied to wooden idols, tombstones, and musical instruments by brushing to extend their service life. Before the first century AD, Egyptians used metal salts as preservatives to soak wood. Chinese people also know that they can be used to prevent corrosion and insects after soaking them in sea water or salt lakes.
500 years ago, the Greeks drilled the round logs of the building, poured oil into the holes and infiltrated them into the cylindrical wood cells, and placed them on the slate for drying. The Romans used alum to treat the wooden pyramids so that they were not within a certain range. Will burn.
For some time thereafter, there was no significant improvement in the infusion process until the pressure infusion method appeared. In 1831, the Frenchman Jean Robert Breant injected preservatives into the wood under pressure, greatly improving the infusion effect of the treated material, which was a milestone in the method of wood infusion treatment. Ten years later, with the gradual resolution of industrial production equipment problems, the pressure treatment method has gradually been promoted.
On the basis of the pressure treatment method, various methods have been developed for the treatment depth, uniformity, and economical use of preservatives, such as the Libin empty cell method, the full cell method, and the Lowry empty cell method. The industrialization of wood infusion treatment began to develop rapidly.
There are two main treatment methods for outdoor wood at home and abroad, the atmospheric pressure method and the pressure method. The former has a brushing method, a spray method, an immersion treatment method, a hot and cold tank method, a double diffusion method, a standing wood treatment method, etc., and is mainly used for the quality of the treated material is not high, the processing amount is small, the durability of the processing material is short, and the like. Occasionally; the latter is also called vacuum-pressurization method, which is mostly used in occasions where the wood size is large, the chemical impregnation is required, and the production volume is large. Commonly used pressurization methods include full cell method, semi-cell method, frequency pressure method, circulation method, etc. Even in the pressure treatment method, there are problems such as insufficient depth of infusion of the treatment material, uneven distribution of the drug, and the like. Although there is a post-vacuum process, the drug remaining in the cell cavity is sucked away, but the drug present in the cell wall space and the cell gap (which cannot be fully utilized) cannot be sucked out of the wood, causing waste of the drug and increasing the cost. In order to improve the permeability and penetration depth of the treated material, various problems existed in the treatment of wood by the pressurization method. In recent years, researchers at home and abroad have continuously explored and proposed many methods.
1. CO2 Supercritical Fluid Treatment of Wood Technology: In the 1995 “Development of New Wood Preservative Processes†(compilation), MorrellJ J et al. introduced an article by Codson on co2 supercritical fluid treatment of wood, which is considered to be almost The treatment agent treats all tree species without significant adverse effects on the treated material. This method is as effective as the current treatment method and broadens the scope of use of the drug. Although further research and experiments are needed, it can be asserted that this method will be the most in this century. Revolutionary improved wood preservative treatment method [1]. Demessie ES et al. used carbon dioxide or a mixture thereof with formaldehyde to study the effect of supercritical fluid treatment on the gas permeability of Douglas fir heartwood. It is believed that two-thirds of the samples have improved permeability, which seems to be related to changes in temperature and pressure. The solvent is irrelevant, indicating that the state is single, solubilizing the extract, and the permeability of some of the samples may be decreased because the dissolved extract is re-precipitated [2].
2. Wood laser scoring method: laser scoring does not destroy wood tissue, and makes the drug easy to inject [3]. Ando Yusuke compared the four types of columns of cedar, Japanese cypress, Douglas fir, and American hemlock, and the ratio of liquid to liquid in the wood. More than 50% of the former, this method can adjust the amount of liquid injection - related to the location of the scratch on the wood. The effects of scoring depth and laser irradiation conditions and laser scoring on wood strength were also studied [4]. Zhong Yuheng studied the influence of the number of pulsed laser irradiation on the shape of the hole. It is considered that the output power is low, the total irradiation time is long, and the number of irradiations has no effect on the hole depth; however, the output power is high, the total irradiation time is short, and the hole increases with the number of irradiation times. The deeper, in addition to the irradiation, the lower the output power, the longer the long exposure time, but the difference becomes smaller as the number of irradiations increases. The result shows that when the total irradiation time is short, compared with the pulse irradiation, Still more than enough to wear deeper holes [5].
3. Low-pressure steam explosion method: According to the low-pressure steam explosion method proposed in Japan's 1993 “Increase in Wood Injection Symposiumâ€, it can break the pores of the lock, improve intercellular conductivity and improve permeability, electron microscopy. The photographs show selective destruction of the pits after the blasting treatment [3].
4. Pre-compression treatment technology: wood anti-corrosion treatment, for heartwood and difficult-impregnated injection materials, the chemical liquid is evenly injected into the interior of the wood, reaching a certain depth is difficult, the wood can be laterally compressed before the pressure, the stress is concentrated on the specific pattern The hole part, the periphery of the pit and the pit film are selectively destroyed, and the tangential strength of the degassing dry material does not decrease the strength and improve the permeability [3]. Sakai Wenzi used a horizontal compression test of the gas-dried test piece in a high-pressure press with a Douglas fir, cedar and cedar heartwood with a water content of 12 to 18.5%, and injected the dyeing liquid into the test piece in the residual deformation state to determine the injection amount. Experiments have shown that there is a significant increase in the amount of injection after compression treatment; in order to obtain a high injection amount, the size recovery of the test piece in the liquid must be large, and in most cases, the recovery can reach 90% before compression; large gas dry material compression The rate is preferably 30-40% or less, and the static modulus of elasticity is less than 10% after treatment. The combination of compression and trenching is used for surface penetration, and the surface of the trench is well infiltrated. Effective [6]. Iida Sui uses seven kinds of coniferous hardwoods to study the effect of the compression method on the permeability of wood. As a result, the amount of permeation of the compressed material differs from that of the uncompressed material. The degree of increase under the same compression rate varies greatly with the tree species. The maximum liquid absorption of the compressed material after changing the temperature and water content reaches the maximum value when the saturated water temperature of the fir is 80 °C, and the compression of the hemlock is 80 °C at the saturated water temperature. The moisture absorption amount is less than the moisture absorption at 30 °C. The optimal treatment conditions vary with the species. The reason for the difference in the maximum liquid absorption can be explained by the difference in the moisture content of the specimen at the time of compression and the dimensional resilience at different temperatures. The maximum liquid absorption and the dimensional recovery rate are linear. From the SEM observation, the occluded pits were destroyed, and the intrusion in the bore coil was also destroyed. These damages promoted the accelerated liquid penetration [7]. In the study of the permeability of the drug, Anwuwenzi chose the American pine heartwood with poor permeability, the end face of 100×100mm and the length of 1000mm, and saw the sections of 700mm and 300mm length respectively. The long section is compressed to 40%, and the two specimens are pressurized to inject the medicament. The agent is selected from naphthenic acid ketone, CFK agent and lead bismuth citrate emulsion, and is dried after being injected. The dry material was sawed laterally from the middle to observe the penetration of the drug. The experimental results show that the agent in the long section is fully saturated to the central part, maintaining high efficacy. Therefore, the compression method can improve the anti-corrosion treatment performance [8]. Les Bois gave a brief introduction to the manufacturing method of the “compressed wood†patent. After immersing the wood (especially cork) with melamine-formaldehyde resin solution, it is placed in the furnace for pre-drying to reduce the moisture in the wood so as not to affect the polymerization of the resin. Compression is then carried out to reduce the volume of the wood while the resin is polymerized to dry the wood again. The bulk density of the wood increases, and the hardness and wear resistance of the wood and dimensional stability are improved [9]. Inoue Yawen of the Institute of Wood Science, Kyoto University, Japan, believes that "compressed material" is a high-density material that is compressed perpendicularly to the direction of wood fibers, and the required strength properties can be obtained according to the degree of homogenization of the material. The difficulty in making compressed materials is the fixation of wood deformation. A practical processing technique is proposed. Compared with the compressed material, the medium density fiberboard is difficult to be made into a thin and homogeneous material, and the compressed material can be made 1 mm thick, and the steam pretreatment can be effectively shaped to facilitate continuous production [ 10]. Шамаев BA is dried using wet wood with a wood content of 10 to 15% urea and compacted to a density Ï = 1000 to 1200 kg/m3. The drying process of wood plasticized with urea during the transverse compression of wood was studied. The loading law of the drying process was proposed in order to minimize the difference between the lateral deformation value and the compressed transverse direction shrinkage value. . A mathematical model of wood deformation under temperature-humidity and mechanical pressure is proposed. Experiments show that the mathematical model is fully applicable to practical applications in large deformation [11].
5. Hot water (steam) treatment method: For coniferous trees, hot water (steam) treatment can remove substances such as arabinogalactose gel coated in pits, open occluded pit pairs, thereby improving permeability; treatment of cooking treatment The greater the strength, the greater the effect of improving permeability. Electron micrographs show cracked pit plugs after cooking [3]. Pretreatment of wood with microwave heating not only improves the heating rate, but also improves the permeability of the agent [12] [13].
6. Oscillating pressurization: Flynn KA studied the method of oscillating while pre-pressurizing wood in 1994. Using five different oscillating schedules, the spruce gas dry and green (about fiber saturation point) were treated with a maximum pressure of 976 and 1465 kg/m3. The treatment effect was based on the absorption of the agent, radial and chord directions. The penetration rate was evaluated and found to have a significant increase in penetration and sorption of preservatives [14]. In 1996, five different preservatives were used to oscillate the spruce material to observe the distribution of the agent in the rim of the edge. Microscopic observation confirmed that the preservatives inside the edge pits were well distributed and the elastic modulus was not significantly reduced. This treatment method can promote the distribution of the agent in the occlusion site [15].
7. Many people have studied the use of enzymes, microorganisms, and bacteria to improve the permeability of wood. In 1993, Militz H applied different enzymes to pretreat spruce columns and sawn timber, followed by pressure infusion of wood preservatives. Studies have shown that enzyme pretreatment significantly improves the ability of the treatment materials to absorb preservatives and preservatives in the treatment materials. The permeability in the process of pressurization with a mixture of different enzymes is mostly very successful. At the same time, the mechanism of enzyme damage to cell pores was discussed [16]. In the same year, Militz H used three different treatment agents to pretreat the spruce (Picea abies L. Karst.), and the spruce material 1 was treated with the enzyme preparation, and the pitted plug of the edge pit was partially destroyed. The edge microfibril destruction, the permeability is obviously improved; 2 by the hot oxalate treatment, the microfibrils of the pit plug are degraded, but the cellulose structure is not damaged; 3 the cold alkali treatment, the edge of the grain The plug is destroyed, but the permeability is not improved [17]. Despot R and other bacteria use bacteria to improve the permeability of fir trees. The paper focuses on the effect of anaerobic bacteria on increasing the permeability of Chinese fir. The specimens with a length of 6m are divided into three groups, one group is not soaked, and the other two groups are immersed in an aqueous solution for one month and two months, then air-dried, the test material is sawn into small samples, and the cells are impregnated with pressurized The method is immersed in an inorganic salt. Studies have shown that the soaking treatment only improves the permeability of the sapwood and has no effect on the heartwood. The sapwood permeability of the samples immersed for one month and two months was 3.17 times and 3.9 times higher than that of the unsoaked ones, respectively. Wood with improved permeability improves the residence and permeability of water-soluble inorganic salts, and the residenceability is increased by 73% and 75%, respectively. The lateral permeability and longitudinal permeability of sapwood are much larger than that of untreated samples. The compressive strength (in the direction of the grain) of the sapwood of the test material was not significantly reduced [18]. Dai S et al. studied the microbial ecosystem in Cryptomeria fortunei and the changes in the pit membrane of the cedar wood samples. After 9 months into the pool, the number of bacteria in the heartwood did not increase, but the number of bacteria at the junction of the wood sapwood and the heartwood was increased immediately after entering the pool [19].
8. Acoustic and ultrasonic treatment: The application of sound waves or ultrasonic waves while pressing the wood is also a research direction to improve the permeability of wood. Nair HU et al. used Douglas fir and the western American yellow pine test material to add sound waves while pressurizing, and the experimental results were compared with conventional pressure treatment. When continuously pressurized for 1.5 to 2 hours, the absorption of the drug treated by Douglas Fir is better than conventional treatment. This continuous treatment can achieve saturation of the Douglas fir test material, indicating that the sonic treatment, the solution can always enter the interior of the wood structure, and under normal processing conditions, it is ineffective. This treatment method is not ideal for the yellow pine specimens in the western United States. The results show that sonication provides a great possibility for the improvement of the pressure treatment method and the treatment of refractory tree wood [20]. Wheat PE and the like use ultrasonic technology to impregnate wood with preservatives. When the white spruce used is impregnated with a saturated solution of sodium fluoride, the fluidity of the liquid in the wood is enhanced, and the absorption of sodium fluoride is also increased at 47 kHz ultrasonic wave [21].
9. Centrifugal Rotation Technology: A new wood treatment technology – impregnating wood in a centrifuge, Ðринкин СМ, etc. introduced the composition of the centrifugal conveyor: a cylindrical cup-shaped housing (with a support float with a bottom plate), a cylindrical flexible impregnation chamber coaxially fixed to the cylindrical cup and connected to the side wall and the bottom plate of the casing by the elastic member, a cylindrical impregnation chamber symmetrical to the rotating shaft, and a transmission mechanism thereof, and it is considered that under normal pressure Centrifugal impregnation increases the amount of wood absorbed by the agent [22] [23].
10. Ito Takashi uses a continuous hot press roll to pressurize and improve the surface properties of the wood by increasing the hardness of the wood surface. The test materials are cypress, red pine, rubber wood, beech and radiata pine, and the treatment agent is glyoxal resin. Pressure or immersion injection, pressure roller temperature 210 ° C, line speed 2.7 m / min, each compression amount of 0.6 mm, the maximum compression can reach 2.0 mm, the surface hardness of all tree species after compression treatment increased by 2 times, and significantly improve the surface Gloss and finish. Treated with glyoxal resin, the size of the compressed material can be stabilized. When the water content reaches 13.5%, it can be completely compressed and solidified. When the water content reaches 9% or more, the rebound of moisture absorption can be effectively controlled [24]. At the same time, Ito Takashi used a hot press roll to treat the Chinese fir, and the treatment agent used a mixture of glyoxal and dipropylene glycol (mixing ratio 1:1), and more than 13.5% of the solution was pre-pressurized into the test piece, and after compression, The dryer was heated in a 150 ° C dryer for 2 h, whereby the compression set was permanently fixed. This is due to the condensation of the resin and the wood component to produce a hydrophobic effect, resulting in higher volume stability due to crosslinking and expansion. The immersion treatment with 18% or more of the solution can remarkably suppress the deformation recovery of the surface portion. It is considered that this is because the surface of the wood penetrates the resin, so that the water is immersed in the form of steam to the inside of the test piece to delay; in order to increase the amount of inhalation of the resin liquid, it is effective to perform pre-compression pretreatment during the immersion treatment [25].
11. Kumar S studied wet wood at different moisture levels, using different pressure treatments that suddenly raise and release pressure. The results were compared to traditional full cell pressure management using the same pressure and time period. The fast-changing pressure method is considered to be a simple and quick method for treating wet wood with high processing properties, and not only the preservative has a high retention in wood but also a more uniform distribution in wood [26].
The wood is treated with anti-corrosion, flame retardant and dimensional stability, which obviously prolongs the service life and improves the performance. It is an indispensable method for structural materials and outdoor materials. Contemporary people are more yearning for nature than ever before. In Japan, 60% of people have a strong desire to return to nature, and hope that more than 70% of people are housed in wood [27]. In recent years, timber-framed houses have entered China, and the construction of forest villas has become fashionable. The wooden structure facilities in public places have gradually increased, and the amount of structural materials and outdoor materials has increased dramatically. The traditional wood treatment method is time-consuming, complicated in equipment structure, high in precision, and general in treatment effect. In order to improve the infusion effect of the medicament, most of the pressure treatment is carried out, supplemented by the above-mentioned various methods, but instead Existing processing techniques are becoming more complex. The development of new wood treatment methods has become inevitable.
Need A reliable case to store and protect your loved Ski goggles, Video goggles, 3D smart goggles or other goggles and glasses? We are factory that can handle all stages of your needs for Bag and case products - from research and design, sampling, mass production, packaging and logistics, We make it worry free and easy to do business. There are an skilled and loyal team of workers and engineers, Our staff is passionate about bags,case,package products,every product details is well taken care of.Feel free to let us know your ideas, problems, see how we can help and make the right solution for you
Research progress on wood infusion treatment technology
Wood used outdoors, due to rain, sand, sunlight, soil infiltration and temperature changes, will cause problems such as decay, mildew, cracking, deformation, and increased fire risk. From the day when humans began to use wood, outdoor materials were faced with anti-bacterial, anti-mildew, insect-proof, flame-retardant, dimensional stability and other treatments.