KR920000756B1 - Process to produce complex compound from ligno cellulose materials - Google Patents

Abstract

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Description

Method for preparing a composite product from lignocellulosic material

The present invention relates to bagasses of sugar cane, stalks of sorghum, corn stalks, sunflower stalks, stems of flax, and other lignocellulosic materials, in particular water-soluble and easy to extract sugars, carbohydrates. The present invention relates to the manufacture of a composite product from that of a non-woody plant containing lysate or saccharides.

More specifically, the present invention provides a composite product without adding an adhesive binder or adhesive from sugar-containing lignocellulosic materials, such as sugar cane bagas, sorghum stalks, corn stalks, sunflower stalks, flax stalks, and the like. It is about manufacturing a. This production is achieved by applying free sugars, carbohydrates or saccharides as an adhesive and an enhancer.

In the production of sugar cane vargas panel products, soluble thermosetting resin binders such as phenol-formaldehyde and urea-formaldehyde are conventionally used, and in this case, more expensive phenol-formaldehyde is used for exterior grade products. have. Most of the total material costs for composite products are due to conventional resin binders. It is economically attractive to manufacture composite products without the use of expensive resin binders. In addition, the binderless manufacturing system simplifies the manufacturing process and reduces manufacturing costs by eliminating mixing operations and equipment. Therefore, it is easily understood from an economic and technical point of view that it is preferable to use the binderless method in the manufacture of the composite product.

In the conventional manufacturing method of vargas panel products, removal of coarse grains and residual glass sugar is indispensable for high quality panel products. These granules are very short and thin-walled cells compared to real fibers, which contain a higher percentage of sugar but do not contribute to the strength of the final product. Since the granules are cotton wool, the excess resin binder will be absorbed, especially if liquid resin is used. The granule also acts like a sponge and if it is not removed from the Vargas composite panel product, it sucks up the water and swells excessively. Vargas also contains the usual 2 to 6% residual sugar, depending on the type of stem, its maturity, the harvesting method and the efficiency of the sugar grinder.

Residual sugars in the vargas may be removed during processing or not minimized, resulting in problems during the manufacture and subsequent use of the board. Sugars should not be chemically compatible with conventional resin binders used in the manufacture of vargas boards, and may interfere with binding and cause a lack of strength. If the remaining sugar is not chemically modified or consumed during hot compression, the sugar starts to ferment when the Vargas board is left in wet conditions, which gives off an unpleasant odor and finally chemical and biological degradation. This will substantially shorten the useful life in the use of Vargas boards.

Therefore, when it is expected to produce satisfactory products from sugar cane vargas, dehydration and desugaring operations are required. Their work not only increases manufacturing costs but also makes the process complex.

Significantly different from the above practice, it has been found that composite vargas products such as architectural boards, furniture boards, reconstituted materials and molded articles can be produced without the use of resin binders and removal of coagulants and residual sugars. Sugars, carbohydrates or saccharides impart not only binders but also reinforcement elements in lignocellulosic materials, resulting in composite products with good strength properties and great dimensional stability.

According to the present invention, this process requires substantially a finely divided material of vargas or other lignocellulosic material which contains a high proportion of free sugars, especially those from non-tree plants. This pulverized material is first dried to 2 to 8% based on low moisture content, preferably oven dry weight. All of these materials may be made of different lignocellulosic or non-lignocellulose materials or may be partially combined with these. The material is molded at a temperature of at least 180 ° C. without addition of a base binder, and at a time sufficient to express a bond on the spot at a sufficient pressure to form the molded article by mixing the material to form a molded article. It turns into an insoluble and insoluble polymer material that is extremely resistant to degradation.

Fine grinding of raw materials is particularly useful. This is because the individual particles, flakes or strands facilitate the forming and forming operations and improve. This is because pulverization also reduces the presence of skin material from the stem of the plant at the same time, thereby minimizing it. The thin outer layer of epidermis, usually of epidermal material, does not accept water and adhesion.

In a binderless system, the finer the particles, the better the product is usually obtained by the main reason of having uniform and close compression between the individual particles and producing a strong bond and a dense and smooth structure. On the contrary, the conventional method is economically impossible to use thin thin particles. This is because the finer the particles, the more expensive the synthetic resin binder needs to be.

In the present invention, when the composite product is combined with lignocellulosic material free of other sugars, it is preferable to use extremely thin particles. Substantially fine particles act like the powdered resin binder in the conventional manufacturing method.

The beneficial effect of using sugar liquor vargas and especially non-tree plants with lignocellulosic material containing other sugars is a sugar and its material which melt during thermoforming and also polymerize and bind the lignocellulosic material in situ. It can be said that it results in the water-soluble substance produced | generated in the inside.

Furthermore, sugars and water-soluble substances that penetrate the cell walls of lignocellulosic tissue will also be denatured and thermally cured to become crosslinked hard materials that will act as enhancers to every corner of the molded article.

The molded article thus exhibits excellent strength properties, dimensional stability and resistance to boiling water and acid hydrolysis. These results are obtained to the highest extent when the lignocellulosic material contains a high proportion of sugars and water soluble substances.

The chemical reactions included in the binding system in the present invention have not been fully elucidated. It is well known that sugars are sensitized by both acid and alkali to form compounds of small molecular weight, and water is then lost from sugar molecules. When the weak acid or pure water under pressure is reacted with sugar at a temperature of 130 to 170 ° C., about 20% of hydroxymethyl-furfural is produced. Other intermediates and furfural derivatives may also be produced from carbohydrates under the same conditions. These derivatives are highly reactive and can be polymerized again to form insoluble crosslinking materials from insoluble at elevated temperatures. The thermosetting bonds thus produced are extremely resistant to boiling water and acid hydrolysis.

It is believed that all or some of the above reactions can be included in the bond production method of the present invention. Moreover, it is believed that chemical alteration of sugars and water-soluble substances at elevated temperatures is an irreversible chemical and physical change and is indispensable in the present invention.

It is presumed that the polymerization bonds and increasing materials of the present invention actually contain furan dehydration products of carbohydrates of hydroxymethyl-furfural.

It has been found that the physical and mechanical properties of sugar cane produced by the present invention can be at least comparable to or better than that of conventional vargas boards prepared by the use of expensive synthetic resin binders. It was.

An exemplary embodiment of the present invention will be described in detail in the following examples.

Example 1

Dry sugarcane vargas with a water content of 3.8% was obtained in a conventional sugar grinding process. It contains 7.2% by weight of water-soluble substances, in which 4.7% of reducing sugars (as glucose) were found. Further experiments showed that Vargas contained about 70% by weight of genuine fibers and 30% by weight of granules.

)입자가 생겼다. 16메시의 타일러(Tyler)체를 통과한 입자를 면층용에 사용하여 16메시보다 큰 입자를 3-층 매트용의 심재로서 사용하였다. 오븐 건조중량에 의한 면심비(面心比)는 1 : 1이었다.Vargas was crushed with a hammer mill and two fractions (

Particles are formed. Particles having passed through a 16 mesh Tyler body were used for the face layer, and particles larger than 16 mesh were used as the core material for the 3-layer mat. The face ratio by oven dry weight was 1: 1.

A board of 500 × 500 × 11.1 mm was hot compressed from this mat for 12 minutes, and the specific gravity at a temperature of 235 ° C. and a pressure of 2.8 MPa was 0.72. During this hot compaction it was recognized that any amount of material other than moisture evaporated in water and various mists. The weight loss of the mat was 8.4%, which was much higher than the water content of the original mat of 3.8%.

This extra weight loss indicates that there was a severe chemical reaction at elevated temperature. The final analysis confirmed that only 0.7% of reducing sugar remained in the finished board. This amount was much lower than that in commercial Vargas boards. According to the bending strength test, the dry MOR (breakdown coefficient) was 16.3 MPa and the dry MOE (elastic modulus) was 3.8 GPa. Wet MOR was 8.6 MPa. Wet bending strength was obtained by immersing the specimen in boiling water for 2 hours, followed by a wet and cold test.

Example 2

The sugar cane shells were made using a sugar cane separator that separates the inner sugar-containing soft kernels from the outer hard layer or shell of the sugar cane stem. Bark vargas contained 28.6% water-soluble substance and 17.3% reducing sugar because no sugar was extracted from it.

The bark vargas was chopped to form a strand containing about 5% water, 1.5 to 3.2 mm in width and thickness. The strands were in the range of 15 to 300 mm in length, oriented in one direction, and formed into composite materials having dimensions of 38 × 50 × 2650 mm and specific gravity of 0.65. The molding temperature was 225 ° C. at a pressure of 3.4 MPa for 30 minutes. According to the bending strength test, the dry MOR was 31.6 MPa and the wet MOR was 18.6 MPa.

Example 3

The sugars were removed by adding the shells of fresh sugar cane made using a sugar cane separator to the boiling process in water for different times. Three batches of husks were boiled for 5, 10 and 30 minutes, respectively, and a fourth batch was included during the experiment as a control without boiling. After boiling the pearls, the shells were dried to have a water content of 8%, and then pulverized with a hammer mill to form a Tyler body of ± 20 mesh. According to chemical analysis, the remaining sugar was inversely proportional to the increase in mercy time. This also shows a nearly linear relationship between the water-soluble substance and the reducing sugar. The following 1st table shows the result of the said mercy process.

[Table 1]

* Content of the fiber as oven dry weight

Each batch of the composition has three specific press temperatures (180, 210 and 240 ° C.), two different press times (10 and 20 minutes) and a compression pressure of 3.4 MPa, with a specific gravity of approximately 500 × 500 × 11.1 mm. Six boards of 0.70 were made.

The water content of the surface layer composition (-20 mesh) was about 9.0%, and that of the deep composition (+20 mesh) was 3.0%. The face ratio by the oven dry weight of the mat was 1: 1. The test results for the 48 boards are shown in Table 2 below.

[Table 2]

As is apparent from the test results shown in Table 2, the properties of the board are being improved as the sugar content of the shell increases. The higher the press temperature and the longer the press time, the better the board quality. The composition boards were mainly extremely fine particles, and thus had a dense and smooth surface and dark brown color, and also had a high content of sugar and water in the surface of the mat. Dimensional stability of fivagas boards, especially those made using higher sugar content and harsh presses, was superior to conventional products. This is due to the binding and enhancing effect of the polymerized sugar.

Example 4

This example illustrates the preparation of a mixed composite product from sugar cane vargas in combination with other lignocellulosic materials.

About 19% of the reducing sugar-containing sugar cane and pivagas were pulverized with a hammer mill and passed through a 20-mesh Tyler sieve. These pivagas crushed pieces were mixed with poplar flakes having the same dimensions in a weight ratio of 70:30. A mat was made from this mixture and hot-pressed for 10 minutes at 235 DEG C and a pressure of 2.8 MPa to produce a board having a specific gravity of 500 x 500 x 11.1 mm. According to the Jeonggok test, dry MOR was 18.2 MPa and wet MOR was 8.1 MPa. The initial bond test gave a tensile vertical strength of 390 KPa.

Example 5

This example shows that the same results are obtained using other sugar-containing lignocellulosic materials.

The stem of sugarcane containing about 18% of reducing sugar was dried to have a water content of 3%, and pulverized with a hammer mill to pass through a 20 mesh sieving body. A board (specific gravity 0.75 at 500 × 500 × 11.1 mm) was made using this composition under the same press conditions as outlined in Example 4. According to the test results, the dry mor was 18.5 MPa, the wet mor was 9.2 MPa, and the initial bond strength was 480 KPa.

Corn stalks containing about 12% solubles or about 7% reducing sugars were dried and crushed with a hammer mill to have a water content of 3% and passed through a 20 mesh Tyler sieve. A board (500 × 500 × 11.1 mm, specific gravity 0.82) was made using this composition under the same press conditions as outlined in Example 4. According to the test results, the dry MOR was 14.3 MPa, the wet MOR was 7.4 MPa, and the initial bond strength was 320 KPa.

Claims (10)

The raw material consisting of sugar-containing lignocellulosic material is separated into particles, fibers, strands, and flakes, and the finely divided raw material is dried to form the raw material into a desired mat. The mat is formed at a temperature of 180 ° C. or higher. Press-heating with sufficient pressure and time to compress the molded product, the adhesive bonds are expressed during that time, and heat-setting on the spot, and insoluble as a binding agent and enhancer resistant to boiling water and acid hydrolysis. And a composite product is prepared from an pulverized sugar-containing lignocellulosic material which is modified by polymerization with an insoluble crosslinking material without adding an adhesive binder. The sugar-containing lignocellulosic material according to claim 1, wherein the sugar-containing lignocellulosic material is sorghum sorghum, corn stalk, corn stalk, sunflower stalk, flax stalk, and other non-wood plants containing sugar and water-soluble substances. A method for producing a composite product without adding an adhesive binder from the lignocellulosic material. The method of claim 1, wherein the sugar is water-soluble, easy to extract, easy to denature free sugar, carbohydrates or saccharide, insoluble and insoluble material that can be thermally cured and bonded and enhanced by applying heat. A method for producing a composite product without adding an adhesive binder from the lignocellulosic material, characterized in that. The insoluble and insoluble crosslinkable polymer according to claim 1, wherein the sugar and the water-soluble substance generated in the lignocellulosic material are chemically modified and thermally cured at an elevated temperature of 180 ° C. or higher to impart a binder and an enhancer to the molded article. A method for producing a composite article without adding an adhesive binder from a lignocellulosic material, characterized in that it is made of a substance. The method for producing a composite product according to claim 1, wherein the thermoforming and press temperature is 220 ° C. or higher, without adding an adhesive binder from the lignocellulosic material. 2. The adhesive from lignocellulosic material according to claim 1, wherein the sugars and water-soluble substances remaining in the finished composite product are significantly reduced by chemical denaturation and weight loss during molding at elevated temperatures of 180 캜 or higher. A method for producing a composite product without adding a binder. The method of claim 1, wherein the addition of the adhesive binder from the lignocellulosic material, characterized in that to produce a composite product in combination with the other lignocellulosic or non-lignocellulose material by pulverizing the sugar-containing lignocellulosic material. How to manufacture a composite product without The method of claim 1, wherein the sugar, water-soluble substance and granules are partially removed or not removed prior to production, to prepare a composite product without adding an adhesive binder from the lignocellulosic material. Way. The lignin according to claim 1, wherein the sugar-containing lignocellulosic material is pulverized to form extremely fine particles or fibers for producing a composite product having strong bonding strength, excellent dimensional stability and compactness, and uniform and smooth thin structure. A method of making a composite product without adding an adhesive binder from the no cellulose material. The adhesive binder according to claim 1, wherein the composite product is a building board, a furniture board, a reconstituted material, a compressed refractory log, and a molded article having a waterproof bond resistant to boiling water and acid hydrolysis. Method for producing a composite product without adding.