KR101761534B1 - A method for producing a straw or rice straw board having improved smoothness and a method for producing the straw or rice straw board - Google Patents

Abstract

The present invention relates to a method of manufacturing a straw or a rice straw board and a board manufactured thereby, and more particularly, to a method of manufacturing a straw or a rice straw board by pressing a fabric reinforcing agent impregnated with a resin onto a surface of a molded board, To a method of producing a straw or rice straw board having improved smoothness.
According to another aspect of the present invention, there is provided a method for manufacturing a straw or rice straw board having improved smoothness, comprising the steps of: preparing a plate material using straw or rice straw as a main material; A fabric stiffener manufacturing step of forming a fabric stiffener by mixing wood pulp and olefin fibers; Impregnating the fabric reinforcement with urea resin or melamine resin; And a reinforcing material pressing step of compressing the fabric reinforcement material impregnated on the surface of the board, wherein depressed portions of the surface of the plate material are filled with the fabric reinforcement material.

Description

FIELD OF THE INVENTION The present invention relates to a straw or rice straw board having improved smoothness and a straw or rice straw board manufactured thereby.

The present invention relates to a method for producing a straw or a rice straw board and a straw or rice straw board manufactured thereby. More particularly, the present invention relates to a straw or rice straw board produced by pressing a fabric reinforcing agent impregnated with resin on the surface of a sheet- The present invention relates to a method for producing a straw or rice straw board having improved smoothness which can be used as an interior material for furniture, an interior or a building, and a straw or rice straw board manufactured thereby.

With the industrialization and urbanization, there has been an increasing interest in the interior that gives an eco-friendly and warm feeling using wood and the like. The wood plate material used for interior furniture, interior materials of buildings, Particle board, medium-density fiberboard, and the like.

However, in the case of wood flake materials, some recycled wood is used for manufacturing, but since it is mainly manufactured by cutting wood for 20 to 30 years, there are problems that cause various side effects in the environmental aspect.

Therefore, in recent years, in order to protect the environment, a variety of researches have been conducted on techniques capable of efficiently producing plate materials using eco-friendly raw materials other than wood. For example, there is plate raw material using straw or rice straw.

Traditionally, rice is used as a stock in Asia and wheat is consumed worldwide. Some of the straw or rice straw, a by-product of wheat and rice harvest, is used for livestock hay, but most of it is simply abandoned.

The discarded straw or rice straw is usually treated by incineration. Since the combustion gas generated during incineration causes air pollution, it is actively encouraged to recycle waste materials at the national level. to be.

However, unlike wood, straw and rice straw are very short fibers having a length of 1 mm or less, and therefore it is difficult to manufacture them as a medium density fiber board. have.

As a technique for manufacturing an environmentally friendly board using such straw or rice straw, Japanese Unexamined Patent Application Publication No. 10-2012-0131893 and Japanese Unexamined Patent Application Publication No. 10-2006-0092161 are disclosed.

The above prior arts are directed to a method for manufacturing a plate material by mixing an eco-friendly material such as rice straw or straw with a binder composed of various resins and thermoforming the mixture.

That is, the above-mentioned prior arts have been made to manufacture boards using the same method as that for producing particle boards, except that the main raw materials are different.

Generally, a particle board is manufactured by a series of processes of crushing a main material and mixing with an adhesive, followed by molding, compression, aging, hot pressing and cooling. The produced board is subjected to three to four turns After polishing, it is cut and sold.

However, in the polishing process, some particle particles fall off from the surface due to the friction between the particle particles on the surface of the board and the abrasive, and thus depressions are generated. In the conventional art, So that a depression of 1 to 5 mm is generated.

Such a depression is made to be concealed by various methods when the surface of the board is finished. In the case of a wood board, since the size of the burble portion is small, the filling method is not limited and the depression can be filled by various methods.

However, in the case of the depression of the prior art, it is possible to conceal PVC, PP or HPM, which is a surface agent having a comparatively thick thickness, in the surface finishing material. However, when the LPM is adhered with a relatively thin LPM, There is a problem that the coating film layer is recessed along the depressed portion due to work such as UV or polyurethane coating, resulting in defects.

That is, conventional techniques can be finely processed only through PVC, PP, HPM, or the like, thereby limiting the method of finishing the surface of the board.

In addition, in the case of Korea, since the board having a high-gloss finish is generally preferred, there is a problem that the above-described conventional techniques, which can not perform the LPM bonding and painting work, are avoided and become popularized.

Therefore, it is necessary to study a method of effectively filling the depression at a reasonable cost in order to use a board made of straw or rice straw as a main material for indoor furniture, building interior material or interior use.

KR 10-2012-0131893 A 2012.12.05. KR 10-2006-0092161 A 2006.08.22.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide a method of manufacturing a flake-like material by pressing a fabric reinforcing agent impregnated with a resin on a surface of a flake- The present invention also provides a method of manufacturing a straw or rice straw board having an improved smoothness which can be used as a furniture, interior, or interior material for building, with filling of the generated depressed portion.

According to another aspect of the present invention, there is provided a method for manufacturing a straw or rice straw board having improved smoothness, comprising the steps of: preparing a plate material using straw or rice straw as a main material; A fabric stiffener manufacturing step of forming a fabric stiffener by mixing wood pulp and olefin fibers; Impregnating the fabric reinforcement with urea resin or melamine resin; And a reinforcing material pressing step of compressing the impregnated fabric stiffener to the surface of the plate-like material, wherein depression of the surface of the plate material is carried out by the fabric reinforcement.

On the other hand, the fabric reinforcement is composed of 50 to 60 parts by weight of natural wood pulp per 100 parts by weight of polypropylene fiber, and has a thickness of 0.4 to 0.6 mm and a basis weight of 100 to 200 g / m 2.

Meanwhile, the impregnation is performed such that the resin content of the fabric reinforcement is 50 to 60% by weight.

The reinforcing material pressing step may include laminating the LPM impregnated paper on the upper portion of the fabric reinforcement, and compressing the fabric reinforcing material and the LPM impregnating paper at the same time.

According to the present invention, since the fabric stiffener is adhered to the surface while being compressed in correspondence with the bending of the molded product, there is an advantage that the surface of the manufactured board is smoothed without any additional finishing treatment.

In addition, since the fabric reinforcing material is uniformly impregnated with the resin acting as an adhesive throughout the fabric, the fabric reinforcing material can be firmly attached to the entire surface of the molding without applying a separate adhesive.

1 is a flow chart of a method of manufacturing a straw or rice straw board according to the present invention;
2 is a photograph showing the surface of a straw or rice straw sheet material;
3 is a photograph of a fabric stiffener applied to the present invention.
4 and 5 are photographs of an embodiment in which a fabric stiffener and an LPM impregnated paper are simultaneously adhered to the surface of the sheet material.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a method of producing a straw or a rice straw board and a straw or rice straw board manufactured thereby. More particularly, the present invention relates to a straw or rice straw board produced by pressing a fabric reinforcing agent impregnated with resin on the surface of a sheet- The present invention relates to a method of manufacturing a straw or rice straw board having improved smoothness which can be used as a furniture, interior or interior decoration material, and a straw or rice straw board manufactured thereby.

2 is a photograph showing the surface of a straw or rice straw sheet material, and Fig. 3 is a photograph of a fabric stiffener applied to the present invention. Fig. 1 is a flow chart of a method of manufacturing a straw or rice straw board according to the present invention.

Referring to FIG. 1, the present invention comprises a plate material manufacturing step, a fabric reinforcement manufacturing step, an impregnating step, and a reinforcing material pressing step.

Here, the fabric stiffener preparation step including the fabric stiffener preparation step and the impregnation step is referred to as a fabric stiffener preparation step, and the fabric stiffener preparation step may be performed prior to the plate material production step.

1. Step (S10)

The plate manufacturing process is a process for manufacturing a plate material using straw or rice straw as a main material. In addition, a mixture of straw, rice straw or straw and rice straw is crushed to a size of 3 to 10 mesh to form particles, Dried to have a moisture content of 5 to 10% by weight, and PMDI adhesive is mixed therewith and is manufactured by hot pressing.

At this time, 8 to 12 parts by weight of an adhesive is mixed with 100 parts by weight of the particles, and mixing is performed by an agitator so that the entire surface of the particles is coated with the adhesive uniformly.

2. fabric  Stiffener manufacturing step (S21)

The fabric reinforcing material producing step is a process for producing a fabric reinforcing material used for improving the smoothness of the flake material in the present invention, wherein the natural wood pulp and the olefin-based fibers are mixed to form a fabric reinforcing material.

The present invention uses straw or rice straw as an eco-friendly material as a main material of the board. It is preferable that the fabric reinforcement is made of a board having more environmentally friendly, soft and warm properties by using natural wood pulp rather than chemical fiber.

Natural wood pulp is a collection of fibers obtained from plants by a mechanical, chemical or mechanical and chemical process, usually composed of those used throughout the industry.

The olefinic fiber is a fiber produced by an olefin resin which is a polymer produced by a chain reaction of olefin units. In the present invention, a fabric reinforcing material is produced by using polypropylene fibers having excellent heat resistance among olefinic fibers.

The fabric reinforcement is formed by mixing 50 to 60 parts by weight of natural wood pulp with 100 parts by weight of polypropylene fiber. The polypropylene fiber used here is a yarn having a diameter of 10 to 30 μm and a length of 200 to 300 mm.

When the natural wood pulp is mixed with less than 50 parts by weight of the natural wood pulp relative to 100 parts by weight of the polypropylene fiber, the effect due to the natural wood pulp is insufficient because the content of the natural wood pulp is small. , There is a problem that the bonding force of the fabric reinforcing material is lowered as the content ratio of the polypropylene fiber decreases.

When the diameter of the polypropylene fiber is less than 10 탆 and the length is less than 200 mm, the cost is decreased as the manufacturing cost increases. When the diameter exceeds 30 탆 and the length exceeds 300 mm, There is a problem that the fabric stiffener produced has a roughened surface and the fibers are not well dispersed.

Accordingly, the fabric reinforcement is made by mixing 50 to 60 parts by weight of natural wood pulp with 100 parts by weight of polypropylene fiber, and the polypropylene fiber is made of yarn having a diameter of 10 to 30 um and a length of 200 to 300 mm.

Meanwhile, as described above, since the fabric reinforcement is for flattening the surface of the plate-like material while concealing the depression formed on the surface of the plate-like material, the fabric reinforcement should have a predetermined thickness. Accordingly, the fabric reinforcement has a thickness of 0.4 to 0.6 mm, and is manufactured to have a basis weight of 100 to 200 g / m 2.

At this time, in the present invention, the straw and rice straw particles are formed to have a size of 3 to 10 mesh, and when the fabric reinforcement is made to have a thickness of less than 0.4 mm, it is difficult to conceal the depression caused by the separation of the particles, The thickness of the fabric stiffener is too thick, which is economically inefficient.

Also, when the fabric reinforcement is manufactured to have a basis weight deviating from 100 to 200 g / m 2, the fabric reinforcement can not be manufactured to a thickness of 0.4 to 0.6 mm.

Accordingly, it is preferable that the fabric reinforcement has a thickness of 0.4 to 0.6 mm and a basis weight of 100 to 200 g / m 2.

3. Impregnation step (S22)

The impregnating step is a step of impregnating the fabric reinforcement with urea resin or melamine resin. When the fabric reinforcement is impregnated, the fabric reinforcement is impregnated with urea resin or melamine resin having a solid content of 40 to 50% And the impregnation is carried out so that the content becomes 50 to 60% by weight.

Thereafter, the impregnated fabric stiffener is dried for a predetermined period of time and has a moisture content of 5 to 8%.

On the other hand, urea resin is a colorless thermosetting resin produced by a condensation reaction of an urea and an aldehyde (mainly formaldehyde), and has advantages of high elongation strength, good bending, high temperature of twisting by heat, and low cost.

BACKGROUND ART Melamine resins are colorless thermosetting resins prepared by the reaction of melamine and formaldehyde. They are widely used as molding materials for tableware, miscellaneous goods, and electric appliances because they are strong against heat, acids and solvents and have excellent electrical properties. Or paper or the like, it is waterproof.

4. Stiffener pressing step (S30)

The reinforcing material pressing step is a step of pressing the fabric reinforcing material impregnated on the surface of the plate-like material. In addition, the fabric reinforcing material is impregnated on the surface of the flake material, and the hot press is pressed so that the fabric stiffener can be adhered to the surface of the flake material.

The fabric stiffener is made of natural wood pulp and, due to its breathable and absorbent properties, easily absorbs the urea resin or melamine resin during impregnation.

The fabric stiffener faded with the resin can be easily adhered to the plate-like material and the fabric stiffener while a part of the resin is discharged by the pressing of the hot press. At this time, the fabric stiffener is compressed in correspondence with the surface curvature of the sheet material, and the surface of the sheet material is flattened.

In addition, the same pressure is applied to the entire surface of the fabric reinforcement by a hot press, and in the case of the other surface of the fabric reinforcement, the fabric reinforcement is inserted into the depressed portion corresponding to the surface curvature of the molding, In the protruding portion, the fabric reinforcement is compressed and depressed portion is filled, thereby increasing the surface smoothness of the plate-like material.

In addition, as described above, the fabric stiffener is a fiber having a large amount of pores formed therein. When the operation is performed after coating, the surface of the fabric can be easily absorbed by the pores.

In the present invention, if the surface finishing of the sheet material is performed by the LPM method, the LPM impregnated paper is laminated on the upper portion of the fabric reinforcement, and then the fabric reinforcement material and the LPM impregnated paper are simultaneously pressed, do.

Conventionally, in order to press the LPM impregnated paper on the surface of the plate-like material, the surface of the plate-like material is planarized, and after the LPM impregnated paper is put thereon, the pressure-pressed paper is used. However, since the flattening process of the plate-like material is performed by polishing, in order to press-press the LPM-impregnated paper by heat, it is absolutely required to carry out a process of thoroughly removing foreign substances generated by polishing.

That is, conventionally, after the plate material is flattened by polishing, the surface finishing of the plate material is required to be performed by a series of processes of removing foreign matter and pressurizing the LPM impregnated paper.

However, in the present invention, since the surface flattening of the sheet material is performed using the resin-impregnated fabric reinforcement, the polishing process of the surface is not required, and thus the step of removing foreign matters can be omitted.

In addition, since the impregnated resin serves as an adhesive, the surface planarization process and the LPM impregnated paper adhesion process can be performed at the same time. That is, since some processes can be omitted in the conventional production process, the manufacturing cost and time are reduced.

The following table shows the conditions of the thermocompression bonding when the fabric stiffener is adhered to the surface of the sheet material alone and when the fabric stiffener and the LPM impregnated paper are simultaneously adhered. The present invention allows the compression step to be performed under the following conditions.

Processing use Types of Adhesion Types of Hot Press Hot pressure temperature
(° C) pressure
(kgf / cm2) time
(sec)
stamp
Processing
Fabric stiffener
Single adhesive Multi daylight press 100-120 10 to 15 35 to 40 Short cycle press 100-120 20-25 30 to 35
LPM
Processing
Fabric reinforcements
LPM impregnated paper
Simultaneous bonding Multi daylight press 180 ~ 200 10 to 15 50 to 55 Short cycle press 180 ~ 200 20-25 40 to 45

4 and 5 are photographs of an embodiment in which a fabric stiffener and an LPM impregnated paper were simultaneously adhered to the surface of a plate-like material, and were thermocompressed for 43 seconds at a temperature of 190 캜 at a pressure of 23 kgf / cm 2 using a short cycle press, And the surface of the finished article manufactured by thermocompression at the same time.

As can be seen from the figure, when the LPM impregnated paper and the fabric reinforcement are thermocompression-bonded, the other surface of the fabric reinforcement is compressed corresponding to the bending of the sheet material, and one surface of the fabric reinforcement material exposed to the outside is flat As the substrate is adhered to the surface of the molded article, the surface of the board that has undergone the surface treatment is smoothly smoothed.

At this time, the fabric reinforcement is uniformly impregnated with the resin acting as an adhesive throughout the fabric, so that the fabric reinforcement is firmly attached to the entire surface of the molding without lifting.

On the other hand, the fabric reinforcements impregnated with the urea resin or the melamine resin are waterproof due to the characteristics of the resin, so that the straw or the rice straw board provided with the impregnated fabric reinforcement has a water resistance characteristic.

That is, a molded product manufactured by using straw or rice straw has an effect of preventing deformation such as expansion or warping of the molded product as the phenomenon of absorbing moisture by the fabric reinforcement is reduced, and the resin impregnated in the fabric reinforcement is hardened A physical effect such as improving the bending strength of the board produced is added.

The following is a test result of water content and bending strength of the straw or rice straw board according to the present invention.

1. Moisture content of board

In order to measure the moisture content of the board, a straw board having a thickness of 15 mm, a medium density fiber board and a particle board were prepared. In this case, the straw board was made of a board having a fabric stiffener (hereinafter referred to as a straw board A) (Hereinafter referred to as " straw board B ").

On the other hand, the straw boards A and B were crushed to a size of 7 mech to form particles, dried to have a water content of 7% by weight, and 10 parts by weight of PMDI adhesive was mixed with 100 parts by weight of the dried particles, Pressure molding.

On the other hand, in the straw board A, 100 parts by weight of polypropylene fiber was mixed with 56 parts by weight of natural wood pulp, and then a fabric reinforcement material having a basis weight of 170 g / m < 2 & After impregnation, the fabric stiffener, which had been dried for a predetermined time to have a water content of 7 wt%, was attached to the surface of the molding using a multi daylight press at a pressure of 13 kgf / cm 2 at a temperature of 110 캜 for 38 seconds.

At this time, the polypropylene fibers and the natural wood pulp used had a diameter of 27 mu m and a length of 250 mm.

The moisture content of the board was measured by keeping the boards in a constant temperature and humidity chamber at 60% humidity at 20 ° C according to the water content test conditions of Section 6.4 of KS F 3200 and measuring the time of 1 day, 5 days, 10 days, 15 days and 30 days And the water content was measured.

(unit : %) day 5 days 10 days 15th 30 days Moisture content
increase Straw board A 4.3 5.8 6.4 6.9 7.2 2.9 B 4.8 7.4 7.8 9.3 9.5 4.7 Medium density
Fiberboard 5.5 6.3 7.0 8.3 8.8 3.3 particle
board 5.4 5.9 7.6 8.5 8.9 3.5

As can be seen from the above table, the straw board to which the fabric reinforcement is adhered exhibits a significantly lower water content increase than the other product groups. The fabric reinforcement has the effect of moisture-proofing, so that the contraction, It is possible to reduce various phenomena such as warping.

2. Measure the bending strength of board

In order to measure the bending strength of the boards, a straw board A and a straw board B having thicknesses of 6, 8, 9, 12, 15 and 18 mm were respectively prepared, and each prepared board was subjected to a bending strength test according to 6.6 described in KS F 3200 Respectively.

At this time, the straw boards A and B used were manufactured under the same conditions as the boards used in the water content test.

(Unit: N / mm2) 6.0mm 9.0mm 12.0 mm 15.0 mm 18.0 mm Average A 17.3 17.5 18.8 15.3 19.2 17.6 B 15.7 16.1 17.2 14.0 18.4 16.3 Difference (A-B) 1.6 1.4 1.6 1.3 0.8 1.3

It can be seen from the above result table that the board to which the fabric reinforcement is adhered has a higher bending strength than the board that is relatively unbonded. It can be seen that the fabric reinforcement has an effect of not only flattening the surface but also improving the strength of the board have.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (5)

A step of producing a plate material using straw or rice straw as a main material;
A fabric stiffener manufacturing step of forming a fabric stiffener by mixing wood pulp and olefin fibers;
Impregnating the fabric reinforcement with urea resin or melamine resin; And
Compressing the impregnated fabric stiffener onto the surface of the sheet material;
/ RTI >
The plate material manufacturing step comprises:
A mixture of straw, rice straw or straw and rice straw is crushed to a size of 3 to 10mesh to form particles, the particles are dried to have a water content of 5 to 10 wt%, and 100 parts by weight of the particles 8 to 12 parts by weight of a PMDI adhesive is mixed with the mixture to form a plate material by thermoforming,
In the impregnating step,
The impregnation is performed such that the resin content of the fabric reinforcement is 50 to 60% by weight,
The reinforcing material pressing step may include:
The LPM impregnated paper is laminated on the upper portion of the fabric reinforcement, and the fabric stiffener and the LPM impregnated paper are simultaneously pressure-
Wherein the fabric reinforcement comprises:
And 50 to 60 parts by weight of natural wood pulp per 100 parts by weight of polypropylene fiber, and having a thickness of 0.4 to 0.6 mm and a basis weight of 100 to 200 g /
The polypropylene fiber may comprise,
A yarn having a diameter of 10 to 30 um and a length of 200 to 300 mm,
The surface of the plate-
Wherein the bag is filled with the fabric reinforcements. ≪ RTI ID = 0.0 > 15. < / RTI >
delete delete delete A straw or rice straw board produced by the method of claim 1.

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