KR100318587B1 - Method and apparatus of preparing an artificial wood with a multi-layered construction via an extrusion process - Google Patents

Abstract

The present invention relates to a continuous method of manufacturing a multi-composite artificial wood by extrusion and a device used therein, according to the present invention, while controlling the moisture content of the kneaded material while kneading and compressing the cellulose-based material and the synthetic resin in a high temperature extruder By branching the melted kneaded material into the inner and outer kneaded material and then integrating the foamed pressure appropriately, the lightweight high-strength artificial wood having the middle portion of the middle density, the middle portion of the low density and the outer portion of the high density can be continuously manufactured. .

Description

TECHNICAL FIELD & apparatus of preparing an artificial wood with a multi-layered construction via an extrusion process}

The present invention relates to a method for producing a multi-composite artificial wood by an extrusion process from a cellulose-based material and a synthetic resin, and to an apparatus used therefor, and specifically, to kneading and compressing the cellulose-based material and a synthetic resin, and to improve moisture content and foaming rate. The method of continuously producing high strength and light multi-composite artificial wood having a middle density center, a low density middle part, and a high density outer part by controlling and cooling, and an extruder, a mold, a calibrator, and a take-out roller used therein. It relates to a device consisting of.

As environmental preservation is emphasized and wood prices continue to rise, there is an urgent need for the development of artificial wood that combines the convenience of work and high strength and light weight with wood.

Many studies have been attempted to meet these demands. However, when artificial wood is manufactured using only synthetic resin, there is a limit in convenience of work such as sawing and nailing, so that a certain amount of cellulose-based materials such as sawdust is mixed with synthetic resin. The method for producing artificial wood was mainly used.

For example, Korean Patent No. 93-15752 discloses that a small amount of stabilizer and plasticizer is added to 50% by weight of sawdust and 50% by weight of waste polyethylene resin, followed by heating and extruding, and then the extrudate is rolled in a rolling roller and calendered. ), A method of manufacturing artificial wood by pressing or extrusion, and Korean Patent No. 93-28659 discloses raw materials, flame retardants, plasticizers including polyethylene, polypropylene and sawdust (5% water content or less) The present invention discloses a method of manufacturing a building plate by blending and extruding subsidiary materials such as a stabilizer and an antioxidant, followed by rolling and cooling to an appropriate plate standard. In addition, Korean Patent No. 94-31055 discloses a method of manufacturing artificial plastic wood by mixing and extruding foreign materials such as sawdust or paper powder into pulverized waste synthetic resin powder, and then molding and cooling by rotary mold. Japanese Patent Application Laid-Open No. 84-53546 discloses a method for producing a vinyl chloride resin composition for synthetic wood by adding and mixing lubricants to vinyl chloride resin, wood flour and other resins.

However, the above-mentioned methods are difficult to produce a uniform product by a single extrusion process due to the influence of non-uniform moisture contained in the cellulose-based material, which requires additional processes such as calendering or pressing, or can be used according to moisture content. Restriction of the system material was required. In addition, the use of additional processes other than the extrusion process is costly in terms of economics, causing a rise in manufacturing costs during mass production, the high density of the final product is not suitable for the demand of light weight. In addition, technologies developed to produce products by single extrusion process also have a limited content of cellulose materials that can be mixed without completely removing moisture in the cellulose materials, making it difficult to produce uniform products, and The product is produced and the weight is satisfactory, but the overall foaming is not enough to be used as a substitute for wood because the strength of the product is not enough. When the moisture is completely removed, a high-density product is formed and the strength is high, but the use of raw materials and the weight of the product A lot went out and could not meet the demand of the weight reduction.

Accordingly, the present inventors have continued to study intensively, using a device consisting of an extruder, a mold, a calibrator and a take-up roller designed in a specific form, after mixing and compressing the cellulose-based material and the synthetic resin to control the water content and foaming rate The present invention was completed by discovering that it is possible to continuously manufacture artificial wood having a high strength and light multi-complex structure by cooling.

It is an object of the present invention to provide a method and apparatus for the continuous production of lightweight high strength artificial wood in a single extrusion process without the use of additional processes such as calendering or pressing.

1 is a schematic diagram of a device according to the invention for use in producing a multi-complex artificial wood,

FIG. 2 is a cross-sectional view of a part (mold 20 and calibrator 30) of the device according to the invention shown in FIG. 1,

3a to 3d are cross-sectional views of artificial wood produced in accordance with an embodiment of the present invention.

<Short description of drawing symbols>

10 melt melter 11 hopper

12: screw 13: motor

14: reducer 15: moisture content control valve

16: feeding zone 17: compression zone

18: metering zone 19: heating block

20: mold 21: mandrel

22: mandrel inner flow path 23: mandrel foam pressure adjusting flow path

24: Insulation material 30: Calibrator

31: internal calibrator 32: external calibrator

40: cooling take-up roller

In order to achieve the above object, in the present invention, (a) mixing and compressing the cellulose-based material and the synthetic resin in a high temperature extruder 10 to adjust the water content of the kneaded product, and (b) melt kneaded product from the extruder 10 Passed through the mandrel 21 inside the mold 20 to branch into internal and external kneaded material, (c) the internal and external kneaded material is introduced into the calibrator 30 to integrate while performing foam pressure control and cooling, (d) It provides a method for producing an artificial wood having a central portion of the middle density, the middle portion of the low density and the outer edge of the high density, comprising taking the cooled kneaded material in the cooling take-up roller 40.

In addition, in the present invention (i) a melt extruder 10 including a screw 12 and having a raw material input hopper 11 and a water content control valve 15 on the top half and the middle half of the screw, respectively; (ii) a mold (20) connected to the second half of the extruder (10) and comprising a mandrel (21) having at least one internal flow passage (22); (iii) a calibrator 30 comprising a cylindrical external calibrator 32 connected to the outlet of the mold 20 and a cylindrical internal calibrator 31 having an internal passageway in communication with the mandrel internal flow passage 22, And (iv) a pair of cooling take-up rollers 40 positioned next to the outlet of the calibrator 30, to provide an apparatus for manufacturing artificial wood according to the present invention.

Hereinafter, the present invention will be described in more detail.

The artificial wood production method of the present invention comprises (a) kneading and extruding the raw materials, (b) branching the extrudate, (c) foaming and cooling, and (d) taking-out step, in particular the step (a) In (), it is essential to adjust the water content of the kneaded material, and in the step (c), to control the foaming rate.

Cellulose-based material used as a raw material in the present invention may be a waste cellulosic material such as sawdust, waste paper or grain bran having a non-uniform moisture content, it is preferable that the moisture content is 5 to 50% by weight. The synthetic resin used as another raw material may preferably be a thermoplastic resin such as polyethylene, polypropylene, polystyrene or polyvinylchloride.

1 is a schematic diagram of a device according to the present invention used to manufacture a multi-composite artificial timber of the present invention. Referring to FIG. 1, a detailed manufacturing process according to the present invention will be described.

In step (a) according to the method of the present invention, the cellulose-based material and the synthetic resin are introduced into the hopper 11 of the extruder 10 and kneaded and compressed while passing the screw 12 in the hot extruder 10. At this time, the mixing ratio of the two raw materials may vary depending on the required physical properties of the final product, it is preferable to add a mixture ratio of the cellulose-based material to the synthetic resin is in the range of 2: 8 to 7: 3.

The extruder 10 is provided with a heating block 19 that provides a heat source to the outside thereof, and the inside is divided into a supply zone 16, a compression zone 17, and a metering zone 18. The screw 12 in the extruder 10 is rotated by a reducer 14 driven by a motor 13. The injected raw materials are kneaded and compressed through the feed zone 16 and the compression zone 17 of the extruder 10, where external heat source is generated by a heating block wound on the extruder barrel, and the friction heat of the raw material and the raw material or the raw material and the extruder screw. By the high temperature and high pressure conditions are formed, the moisture contained in the cellulose-based material is vaporized. At this time, the pressure can be set at the upper end of the screw extruder, and through the water content control valve 15 that automatically opens and closes when the set pressure is reached, by releasing the desired amount (excess moisture) of the vaporized water to the outside The content of water in the kneaded material can be adjusted, preferably, 5 to 15% by weight. The water content controlled kneaded material is then introduced into the mold 20 through the metering zone 18 of the latter half of the screw 12.

In step (b) according to the method of the present invention, the kneaded material introduced into the mold 20 is branched into two parts of the inner and outer kneaded material by the mandrel 21 present inside the mold to open the mold 20. Will pass. 2 shows in detail the structure of the mold 20 and the calibrator 30 in the device according to the invention shown in FIG. 1. Referring to FIG. 2, the mandrel 21 has one or more mandrel inner flow passages 22 for branching the kneaded material, and a plurality of different caliber mandrel foaming pressure control flow passages 23. It controls the foaming rate of kneaded material passing through) and is designed to be forward and backward.

The kneaded material in the extruder 10 and the mold 20 of steps (a) and (b) is maintained at high pressure and high temperature, preferably at a pressure in the range of 1 to 700 psi and at a temperature of 100 to 250 ° C. Do. The inner and outer kneaded material passing through the mandrel 21 is then introduced into the calibrator 30.

In step (c) according to the method of the present invention, the internal and external kneaded material introduced into the calibrator 30 starts foaming by residual moisture as it gradually changes from a high pressure and a high temperature state to an atmospheric pressure state, and internal And the external calibrators 31 and 32 are cooled independently (at different speeds), respectively.

The internal kneaded material is cooled while passing through a cylindrical internal calibrator 31 having an internal passage communicating with the mandrel internal flow passage 22, thereby suppressing foaming as much as possible and forming a medium density layer. It acts as a reinforcement core as a core of the product, increasing elastic modulus and restoring force.

On the other hand, the outer kneaded material is cooled while being introduced into the cylindrical outer calibrator 32 connected to the outlet of the mold 20 so that the outer portion contacting the surface of the outer calibrator 32 is foamed to the maximum extent to form a high-density hard layer. As a result, foaming into the interior is relatively free, forming a low density layer therein. At this time, it is preferable to adjust the temperature of the internal and external calibrators 31 and 32 in the range of 10 to 70 ° C., and the temperature is controlled by the coolant passing through the coolant passages (inlet and outlet passages) mounted on the calibrator. Is performed.

In step (c), the foaming pressure is adjusted by opening and closing a plurality of foaming pressure adjusting flow passages 23 of different diameters in communication with the space between the inner and outer calibrator present in the mandrel 21 to adjust the foaming pressure. The foaming rate can be adjusted. The external kneaded material may also be cooled in multiple stages by passing through two or more series of external calibrator 32 set to different lengths and temperatures from each other.

According to the present invention, since the internal calibrator 31 is shorter in length than the external calibrator 32, the mixtures of layers having different densities are coalesced before exiting the calibrator 30. In addition, the inner and outer calibrators 31 and 32 are connected by the mandrel inner flow passage 22 and the outlet of the mold 20 and the heat insulator 24, in particular, the inner calibrator 31 is connected to the mandrel 21. It is composed of double tube to prevent heat transfer and is designed to apply vacuum inside. The extrudate comprising several hard layers of different densities is then introduced into a cooling take-up roller 40 located after the outlet of the calibrator 30.

In step (d) according to the method of the present invention, the kneaded material is introduced into the cooling take-out roller 40 to be cooled and taken out. Through such take-out, it is possible to prevent breakage during tension caused by mixing a large amount of cellulose-based material.

The artificial wood finally produced according to the present invention, the center (core) portion, the middle portion and the outer portion is composed of a medium density layer, a low density layer and a high density layer, respectively, has a high strength and light characteristics. Specifically, the density of the low density layer of the middle portion is 0.3 to 0.7 g / cm ³ , preferably 0.3 to 0.5 g / cm ^3, and the density of the middle (core) portion of the medium density layer is 0.7 to 1.2 g / cm ³ , Preferably it is 0.7 to 0.85g / cm ³ , the density of the outer high-density layer is 0.8 to 1.4g / cm ³ , preferably 1.2 to 1.3g / cm ³ , to be appropriately adjusted within the above range depending on the end use Can be. At this time, the density value may have a relatively large deviation depending on the type of raw material used, but the relative density of the corresponding site, that is, the low, medium, and high density of the middle, center, and outer portions is maintained.

According to the apparatus of the present invention comprising an extruder, a mold, a calibrator, a take-up roller, and the like, which is used to manufacture the artificial wood of the present invention, the artificial wood of the multiple composite structure as described above can be continuously produced.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the invention only.

Example 1

Using the apparatus shown in FIG. 1, the hopper 11 of the extruder 10 with a sawdust having a non-uniform moisture content (average of 30% by weight) and a high density polyethylene resin (melt index = 7 g / 10 min) in a ratio of 5: 5. ). After the input raw material was kneaded and compressed in the extruder 10, the water content of the kneaded product was adjusted using the water content control valve 15, and then the kneaded material was introduced into the mold 20 to pass the mandrel 21. At this time, the kneaded material in the extruder 10 and the mold 20 was processed under the conditions of 5 to 80 psi and 130 to 180 ° C. Subsequently, the internal and external kneaded material passing through the mandrel 21 is introduced into the internal calibrator 31 and the external calibrator 32 to perform foam pressure adjustment and cooling, and the temperature of the internal calibrator 31 is 40 ° C. The temperatures of the three consecutive external calibrators 32 were set to 15, 20 and 35 ° C, respectively. Subsequently, the cooled and integrated kneaded material was cooled and drawn in a cooling take-up roller 40 to produce an artificial wood having a square bar shape having a multilayer structure.

The core density of the manufactured artificial wood was 0.8g / cm ³ , the density of the middle part was 0.5g / cm ³ , and the density of the outer part was 1.2g / cm ^3, and its cross-sectional view is shown in FIG. 3A.

Example 2

Using the apparatus shown in Fig. 1, the hopper 11 of the extruder 10 with a sawdust having a non-uniform moisture content (average 20 wt%) and a polypropylene resin (melt index = 4 g / 10 min) at a ratio of 5: 5. ). After the inputted raw material was kneaded and compressed in the extruder 10, the water content of the kneaded product was adjusted using the water content control valve 15, and then the kneaded material was introduced into the mold 20 to pass the mandrel 21. At this time, the kneaded material in the extruder 10 and the mold 20 was processed under the conditions of 5 to 150 psi and 150 to 200 ° C. Subsequently, the internal and external kneaded material passing through the mandrel 21 is introduced into the internal calibrator 31 and the external calibrator 32 to perform foam pressure adjustment and cooling, and the temperature of the internal calibrator 31 is 40 ° C. The temperatures of the two consecutive external calibrators 32 were set to 15 and 40 ° C, respectively. Subsequently, the cooled and integrated kneaded material was taken out in the take-out roller 40 to produce a circular bar-shaped artificial wood having a multilayer structure.

Core density of the manufactured artificial wood was 0.85g / cm ³ , the middle density is 0.5g / cm ³ , the outer density is 1.25g / cm ³ , its cross-sectional view is shown in Figure 3b.

Example 3

Using the apparatus shown in FIG. 1, the hopper 11 of the extruder 10 with a chaff and a polystyrene resin (melt index = 5 g / 10 min) having a non-uniform water content (average 35 wt%) in a ratio of 4: 6. Was put in. After the input raw material was kneaded and compressed in the extruder 10, the water content of the kneaded product was adjusted using the water content control valve 15, and then the kneaded material was introduced into the mold 20 to pass the mandrel 21. At this time, the kneaded material in the extruder 10 and the mold 20 was processed under the conditions of 5 to 150 psi and 130 to 180 ° C. Subsequently, the internal and external kneaded material passing through the mandrel 21 is introduced into the internal calibrator 31 and the external calibrator 32 to perform foam pressure adjustment and cooling, and the temperature of the internal calibrator 31 is 20 ° C. The temperatures of the three consecutive external calibrators 32 were set to 15, 20 and 40 ° C, respectively. Subsequently, the cooled and integrated kneaded material was taken out in the take-out roller 40 to produce a square bar-shaped artificial wood having a multilayer structure of a double core.

The core density of the manufactured artificial wood was 0.9g / cm ³ , the middle density was 0.6g / cm ³ , and the outer density was 1.3g / cm ^3, and its cross-sectional view is shown in FIG. 3C.

Example 4

The hopper 11 of the extruder 10 with a chaff having a nonuniform water content (average 15 wt%) and polyvinyl chloride resin (melt index = 5 g / 10 min) using a device shown in FIG. ). After the input raw material was kneaded and compressed in the extruder 10, the water content of the kneaded product was adjusted using the water content control valve 15, and then the kneaded material was introduced into the mold 20 to pass the mandrel 21. At this time, the kneaded material in the extruder 10 and the mold 20 was processed at 5 to 20 psi and 160 to 210 ° C. Subsequently, the internal and external kneaded material passing through the mandrel 21 is introduced into the internal calibrator 31 and the external calibrator 32 to perform foam pressure adjustment and cooling, and the temperature of the internal calibrator 31 is 15 ° C. The temperatures of the four consecutive external calibrators 32 were set to 15, 20, 25 and 40 ° C, respectively. Subsequently, the cooled and integrated kneaded material was taken out in the take-out roller 40 to produce a square bar-shaped artificial wood having a multilayer structure of a double core.

The core density of the manufactured artificial wood was 0.95g / cm ³ , the middle density was 0.7g / cm ³ , and the outer density was 1.4g / cm ^3, and its cross-sectional view is shown in FIG. 3D.

According to the method of the present invention, a light weighted high strength, having a suitable density and multilayer structure depending on the application, on a single extrusion process using waste cellulose based materials having a non-uniform moisture content without the need for additional processes such as calendering or pressing The artificial wood can be produced efficiently and economically, and the manufactured artificial wood of the present invention can be variously applied to formwork or pallet products.

Claims (14)

(a) controlling the moisture content of the kneaded product while kneading and compressing the cellulose-based material and the synthetic resin in the high temperature extruder 10, and (b) the melted kneaded product from the extruder 10 is mandrel inside the mold 20 ( 21) and branched into the internal and external kneaded material, (c) the internal and external kneaded material is introduced into the calibrator 30 to integrate while adjusting the foam pressure and cooling, and (d) cooling the cooled kneaded material Including taking in the take-out roller 40, A method for manufacturing artificial wood having a central density, a low density intermediate portion, and a high density outline portion. The method of claim 1, And the cellulose based material is a waste cellulose based material selected from the group consisting of sawdust, waste paper, grain bran and mixtures thereof. The method according to claim 1 or 2, A cellulose-based material containing from 5 to 50% by weight of water. The method of claim 1, The synthetic resin is a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl chloride and mixtures thereof. The method of claim 1, Characterized in that the ratio of the cellulose-based material to the synthetic resin is in the range of 2: 8 to 7: 3. The method of claim 1, Characterized in that steps (a) and (b) are carried out at a pressure of 1 to 700 psi and a temperature of 100 to 250 ° C. The method of claim 1, The cooling of step (c) is carried out at a temperature of from 10 to 70 ° C. The method of claim 1, The density of the middle portion is 0.3 to 0.7 g / cm ³ , the density of the central portion is 0.7 to 1.2 g / cm ³ , and the density of the outer portion is 0.8 to 1.4 g / cm ³ . (i) a melt extruder (10) comprising a screw (12) and having a hopper (11) and a water content control valve (15) for inputting raw materials on top and middle portions of the screw, respectively; (ii) a mold (20) connected to the latter half of the extruder (10) and comprising a mandrel (21) having at least one internal flow passage (22); (iii) a calibrator 30 comprising a cylindrical external calibrator 32 connected to the outlet of the mold 20 and a cylindrical internal calibrator 31 having an internal passageway in communication with the mandrel internal flow passage 22, And (iv) a pair of cooling take-up rollers 40 located after the outlet of the calibrator 30, Apparatus used in the method according to claim 1. The method of claim 9, And the mandrel has a plurality of foam pressure regulating flow passages of different apertures in communication with the space between the inner and outer calibrator. The method of claim 9, Wherein the internal calibrator is shorter in length than the external calibrator. The method according to claim 9 or 11, Wherein the calibrator comprises two or more external calibrator set to different lengths and temperatures from each other. The method of claim 9, Device characterized in that the internal calibrator consists of a double tube. The method of claim 9, Wherein the inner and outer calibrator are connected with the outlet of the mandrel inner flow path and the mold, respectively, by means of insulation.