CN102179855B - High-strength structural artificial board and manufacturing method thereof - Google Patents

Abstract

The invention discloses a method for manufacturing a high-strength structural wood-based panel. Cut the industrial hemp stalks into 40-50cm long hemp stalks, split them longitudinally from the axis, adjust the moisture content of the hemp stalks to 80-100%, and flatten the hemp stalks non-destructively. It is made after billet, sizing, hot pressing, conditioning and tempering at constant temperature and humidity. The invention utilizes the characteristics of high strength, porosity and low density of industrial hemp stalks for the first time to manufacture structural wood-based panels. Compared with similar wood products, the product has the characteristics of low density, high strength and good load-bearing performance. The implementation of this technology can not only significantly save wood resources and protect the ecological environment, but also turn waste into wealth, providing a new way for the application of industrial hemp. It helps to promote the further development of the industrial hemp industry and has good social and economic benefits.

Description

A method for manufacturing high-strength structural wood-based panels

technical field

The invention belongs to the technical field of wood-based panel processing, and in particular relates to a high-strength structural wood-based panel prepared from industrial hemp stalks. At the same time, the invention also relates to a manufacturing method of the high-strength structural wood-based panel. the

Background technique

Cannabis is a woody herbaceous plant belonging to the phylum Angiosperms, Magnolia, Hamamelis, Urtica, Cannabis, Cannabis genus, scientific name Cannabis sativa L., common name Hanma, Hanma, thread hemp, flower hemp etc. There are about 150 varieties. The "United Nations Convention against Illicit Trafficking in Narcotic Drugs and Psychotropic Substances" promulgated in 1988 clearly stipulates that cannabis plants containing tetrahydrocannabinol (THC) < 0.3% no longer have the value of extracting THC toxic components, and there is no direct smoking as drugs. Value, this kind of hemp variety specially designed for industrial use - industrial hemp, can be cultivated on a large scale and used industrially. At present, industrial hemp is widely used for its bast fiber part and seed part, which are mainly used in textile and food industries; while industrial hemp stalk is its waste, which has not been rationally utilized at present and is burned on the spot. my country is one of the major industrial hemp-growing countries in the world. In 2009, the planting area of industrial hemp in Yunnan Province alone reached 100,000 mu. The growth period is 3-6 months, and each mu of land can produce 1.5-2 tons of hemp stalks. In addition, the extensive application of hemp husks and hemp seeds in military and civilian industries has drawn great attention from the Party Central Committee, stimulating the rapid development of the hemp planting industry. In 2010, the planting area of industrial hemp stalks in Yunnan Province reached 300,000 mu , and it is estimated that the planting area of industrial hemp stalks in the country will reach 10 million mu in 2015. At that time, 15-20 million tons of hemp stalks will be produced. If half of these hemp stalks can be used to make wood-based panels, 7.5-10 million m ³ of wood-based panels can be produced (about 100% of the total production of wood-based panels in China in 2006. 10%-13%), can save 10-14 million mu of forest resources every year, and can also reduce environmental pollution caused by burning hemp stalks. Not only waste utilization, but also the performance advantages of industrial hemp stalks can be used to improve the product performance of man-made panels. It has obvious ecological and economic benefits.

The skin strength of industrial hemp stalks is high, and the density of hemp stalks is low, about 0.25g/cm ³ , only 1/3 to 1/2 of the wood density (referring to the wood raw materials commonly used in the manufacture of wood-based panels). However, its diameter is small (5-8cm in diameter) and cylindrical. How to process the material flat without destroying the characteristics of the raw material itself has become a technical problem in the preparation of structural materials from industrial hemp stalks.

Contents of the invention

The purpose of the present invention is to address the deficiencies of the prior art, provide a high-strength structural wood-based panel processed from industrial hemp stalks as the main raw material, expand the application of industrial hemp, protect the ecological environment, and promote the further development of the industrial hemp industry. the

The object of the present invention is also to provide a method for manufacturing the high-strength structural wood-based panel. the

The purpose of the present invention is achieved through the following technical solutions. the

Unless otherwise stated, the percentages used in the present invention are all percentages by weight. the

A high-strength structural wood-based panel, which is characterized in that: firstly cut the industrial hemp stalks into 40-50cm long hemp stalks, then split the hemp stalks longitudinally from the axis, and then adjust the moisture content of the hemp stalks to 80-100%, and the non-destructive flattening of the hemp stalks, and then it is made after forming blanks, sizing, hot pressing, and constant temperature and humidity conditioning. Among them, the total amount of sizing on the upper and lower sides of each layer of slabs is 180～300g/m ² .

The glue is selected from one of urea-formaldehyde resin, phenolic resin, melamine-modified urea-formaldehyde resin, isocyanate or natural high molecular polymer. the

Described natural macromolecular polymer is preferably bean gum or starch glue. the

The hot pressing is selected from one of flat pressing, mold pressing, extrusion, spray steam hot pressing, high frequency hot pressing or vacuum hot pressing. the

The method for manufacturing the high-strength structural wood-based panel, comprising the following steps:

(1) Raw material processing: Cut the industrial hemp stalks into 40-50cm long hemp stalks, split the hemp stalks longitudinally from the axis, and perform humidification treatment on the hemp stalks to make the moisture content 80 ~100%, and then carry out non-destructive flattening treatment at a temperature of 80~120°C and a pressure of 2.5~3.0MPa;

(2) Sanding and drying: Sand the flattened hemp stalks to determine the thickness, make wood chips with a thickness of 5-8mm, and dry them at a temperature of 100-120°C until the moisture content is 5-8%;

(3) Glue application and slab assembly: glue the wood chips into the required format and then apply glue. The total amount of glue applied to the upper and lower sides of each layer of slabs is 180-300g/m ² ; Assembling blanks to make plates with a density of 0.65-0.85g/cm ³ and a thickness of 10-30mm;

(4) Hot pressing: hot pressing the plate at a temperature of 90-120 °C and a pressure of 1.5-5.0 MPa, and the hot-pressing time is 1.0-2.0 min/mm;

(5) Post-treatment of boards: The hot-pressed boards are placed at a temperature of 25-30°C and a humidity of 50-60% for constant temperature and humidity treatment for 48 hours to obtain the required high-strength structural wood-based panels.

Compared with the prior art, the present invention has the following advantages: It is the first to use the characteristics of high strength, porosity and low density of industrial hemp stalks to manufacture structural wood-based panels, specifically including glulam, veneer graded timber and blockboard. Compared with similar wood structural panel products, this product has the characteristics of low density, high strength and good load-bearing performance, and can be used in the preparation of furniture, walls, wooden doors, packing boxes and other fields. The implementation of this technology can not only significantly save wood resources and protect the ecological environment, but also turn waste into wealth, which provides a new way for the application of industrial hemp and helps to promote the further development of the industrial hemp industry, with good social and economic benefits. benefit. the

Detailed ways

The present invention will be further described in detail below in conjunction with the examples, but the examples are not intended to limit the technical solution of the present invention. Anyone familiar with the technical field within the technical scope disclosed in the present invention, according to the scheme of the present invention and its inventive concepts to make equivalent replacements or changes shall be covered by the protection scope of the present invention. the

Example 1 Preparation of industrial hemp stalk blockboard

Use a cross-cut saw to cut the industrial hemp stalks into 40-50cm long hemp stalks, then split the hemp stalks longitudinally from the axis, and humidify the hemp stalks so that the moisture content is 80%. Then use a hot press to flatten it at a temperature of 120°C and a pressure of 3.0MPa to ensure that there are no cracks or cracks in the flattened industrial hemp stem that affect the strength of the industrial hemp stem, that is, non-destructive development. flat. Sand the flattened hemp stalks with a belt sander to determine the thickness to make wood chips with a thickness of 5mm, and use a constant temperature and humidity dryer to dry the hemp stalks at a temperature of 100°C until the moisture content is 5-8%. After assembling the wood chips into a format of 2440×1220mm, use a glue machine to apply glue. The adhesive used is urea-formaldehyde resin adhesive. The total amount of glue applied to the upper and lower sides of each layer of slabs is 180g/m ² ; the blanks are assembled according to the principle of vertical symmetry , to make a plate with a density of 0.65g/cm ³ and a thickness of 10mm. Plate preparation was carried out under the conditions of hot pressing temperature 90° C., hot pressing time 2.0 min/mm, and hot pressing pressure 1.5 MPa. Under the condition of temperature 25～30℃ and humidity 50～60%, the panel was subjected to constant temperature and humidity treatment for 48 hours, and then the performance test of the panel was carried out. The test results are shown in Table 1.

Example 2

Repeat Example 1, there are the following differences: the moisture content of the hemp stalk section after humidification is 90%, and the non-destructive flattening treatment is carried out at a temperature of 100 ° C and a pressure of 3.5 MPa; the total amount of sizing on the upper and lower sides of each layer of slab is 240 g/m ² ; board density 0.75g/cm ³ , thickness 15mm; board hot-pressing conditions: hot-pressing temperature 110°C, hot-pressing time 1.5min/mm, hot-pressing pressure 3.5MPa. Test results are shown in Table 1 shown.

Example 3

     Repeat Example 1, with the following differences: the moisture content of the hemp stalk section after humidification is 100%, and the non-destructive flattening treatment is carried out at a temperature of 120°C; the total amount of glue applied to the upper and lower sides of each layer of slab is 300g/m ² The density of the board is 0.85g/cm ³ , and the thickness is 20mm.

Example 4 Preparation of industrial hemp stalk laminated lumber

Example 1 was repeated, with the following differences: the billets were assembled in the same direction, and the test results are shown in Table 1.

Example 5

Example 2 was repeated, with the following difference: the billets were assembled in the same direction, and the test results are shown in Table 1.

Example 6

Example 3 was repeated, with the following difference: the billets were assembled in the same direction, and the test results are shown in Table 1.

Example 7

Repeat Example 1, with the following differences: the blanks are formed in the same direction, the adhesive used is a phenolic resin adhesive, and the total amount of glue applied to the upper and lower sides of each layer of slab is 180g/m ² ; the test results are shown in Table 1 .

Example 8

Repeat Example 2, with the following differences: the blanks are formed in the same direction, the adhesive used is a phenolic resin adhesive, and the total amount of glue applied to the upper and lower sides of each layer of slab is 220g/m ² ; the test results are shown in Table 1 .

Example 9

Repeat Example 3, with the following differences: the blanks are formed in the same direction, the adhesive used is a phenolic resin adhesive, and the total amount of glue applied to the upper and lower sides of each layer of slab is 260g/m ² ; the test results are shown in Table 1 .

Claims (5)

1. the manufacture method of a high-strength structural artificial board, it is characterized in that: first with the long hemp stalk section of the transversal one-tenth 40～50cm of industrial hemp stalk, again the hemp stalk section is vertically rived from the place, axle center, regulate afterwards hemp stalk section moisture content to 80～100%, and the hemp stalk section be can't harm flattening, make after applying glue, assembly, hot pressing, constant temperature and humidity modifier treatment, wherein, the applying glue total amount of every laminate base upper and lower surface is 180～300g/m again ²Specifically may further comprise the steps:

(1) raw material is processed: with the long hemp stalk section of the transversal one-tenth 40～50cm of industrial hemp stalk, again the hemp stalk section is vertically rived from the place, axle center, the hemp stalk section is carried out humidification to be processed, making its moisture content is 80～100%, then 80～120 ℃ of temperature, under pressure 2.5～3.0MPa condition, it be can't harm flattening process;

(2) sanding and drying: the hemp stalk section sanding after will flattening is fixed thick, makes the wood chip of thickness 5～8mm, and is that to be dried to moisture content under 100～120 ℃ of conditions be 5～8% in temperature;

(3) gluing and assembly: wood chip is combined into the breadth after dryer sizing of required specification, the applying glue total amount of every laminate base upper and lower surface is 180～300g/m ²Carry out assembly according to same direction or vertical symmetry principle again, making density is 0.65～0.85g/cm ³, thickness is the sheet material of 10～30mm;

(4) hot pressing: 90～120 ℃ of temperature, under pressure 1.5～5.0MPa condition to sheet material hot pressing, hot pressing time 1.0～2.0min/mm;

(5) sheet material post processing: the sheet material that hot pressing is good places constant temperature and humidity processing 48h under 25～30 ℃ of temperature, humidity 50～60% conditions, namely obtains required high-strength structural artificial board.

2. the manufacture method of high-strength structural artificial board according to claim 1 is characterized in that: described glue is selected from a kind of in Lauxite, phenolic resins, cyanurotriamide modified urea resin or the isocyanates.

3. the manufacture method of high-strength structural artificial board according to claim 1, it is characterized in that: described glue is natural polymers.

4. the manufacture method of high-strength structural artificial board according to claim 3, it is characterized in that: described natural polymers is bean gum or amylan.

5. the manufacture method of high-strength structural artificial board according to claim 1 is characterized in that: described hot pressing is selected from a kind of in flat-press process, die pressing, extrusion, steam injection pressing, High frequency heating or the vacuum hotpressing.