KR101050270B1 - Synthetic wood for inhibiting thermal expansion - Google Patents

Abstract

PURPOSE: A synthetic lumber for thermal expansion suppression is provided to fit the quality standard by preventing the thermal transformation of the synthetic lumber even exposed to the sunshine for a long time by secluding not only the ultraviolet ray but also the near infrared ray. CONSTITUTION: An additive contains the stabilizer including the near infrared ray absorber in which the maximum absorption wavelength is 800 to 1000nm. The near-infrared absorber is formed by adding the near infrared ray absorption dye in the binder solution dissolving polymethyl-methacrylate in the NMethyl-2-pyrrolidone. The synthetic lumber comprises the reinforcement part which is formed to connect from one side of pipe inner circumference to the other side of the inner circumference to increase the pipe of the hollow structure and the intensity of the pipe. The pipe is formed in the base part which forms flat side and the edge of the base part, and interconnects both side part and end part which are at right angle to the base part, and comprises streamline dome part which is formed bulging to the direction far from the base part.

Description

Synthetic wood for inhibiting thermal expansion

The present invention relates to a thermal expansion inhibiting synthetic wood, and more particularly to a thermal expansion inhibiting synthetic wood that can prevent thermal deformation within a range suitable for quality standards even if exposed to long-term exposure to the sun.

Generally, natural wood is mainly used as exterior materials or interior materials of buildings such as floorboards, ceiling boards, doors, door frames, windows, fences, and decks. Natural wood is mainly used as interior and exterior materials of buildings because the consumer's preference for wood and aesthetics due to natural texture are improved.

However, the interior and exterior materials of buildings using natural wood have problems of forest damage due to timber felling and environmental damage due to the release of harmful substances in fire. In particular, water resistance, heat resistance, There is a problem in that physical properties such as impact strength, bending strength, dimensional stability, flame retardancy, weather resistance, and antibacterial property are deteriorated.

In order to solve this problem, synthetic wood having a similar texture and appearance to natural wood has been widely used as interior and exterior materials of buildings.

Synthetic wood is made by extrusion processing a synthetic wood composition, which is a mixture of wood or powdered wood powder powdered by grinding rice such as straw, corn stalks, and pulp, and a resin such as polyvinyl chloride (PVC). Such synthetic wood has improved water resistance, heat resistance, dimensional stability, flame retardancy, and antimicrobial properties, compared to natural wood, and has an effect of reducing manufacturing cost due to low price.

However, synthetic wood has a problem in that when exposed to sunlight when installed outdoors, the weather resistance is lowered, such as thermal deformation, discoloration, photolysis of the resin. To this end, conventional synthetic wood has added a certain amount of ultraviolet absorber to prevent the change of physical properties due to photochemical reaction or light absorption.

Sunlight, or sunlight, is an invisible light that appears outside the short wavelength of visible light and emits ultraviolet and near-infrared light. Ultraviolet rays are called chemical rays because of their strong chemical action, and near-infrared rays are visible rays It is called a hot wire because it has a stronger heat action than ultraviolet rays. Such near-infrared rays rapidly increase the temperature of the synthetic wood by thermal action, resulting in thermal deformation of the synthetic wood.

Therefore, in the case of using a UV absorber as in the prior art to some extent to reduce or prevent discoloration or photochemical reaction of the synthetic wood by absorbing ultraviolet rays contained in the sunlight, there is a problem that can not prevent thermal deformation.

The present invention has been made to improve the above problems, and the object of the present invention is to provide a synthetic wood for inhibiting thermal expansion suitable for quality standards by preventing not only ultraviolet rays but also near-infrared rays to prevent thermal deformation of synthetic wood even when exposed to the sun for a long time. .

Synthetic wood for inhibiting thermal expansion of the present invention for achieving the above object is formed by molding a composition containing wood powder 35 to 75% by weight, polyolefin resin 20 to 50% by weight, additives 2 to 20% by weight, the additive is And a stabilizer comprising a near infrared absorber formed by adding a near infrared absorbing dye to a binder solution in which polymethyl methacrylate is dissolved in NMethyl-2-pyrrolidone.

The synthetic wood is characterized in that it comprises a hollow hollow tube and a reinforcing rib formed to protrude on the inner peripheral surface of the tube to increase the strength of the tube.

The synthetic wood is characterized in that it comprises a hollow hollow structure and the reinforcing portion formed to connect the other side of the inner circumferential surface on one side of the inner circumferential surface of the tube to increase the strength of the tube.

The tubular body is formed at both edges of the base part and the base part to form a smooth surface, and both sides are formed at right angles to the base part, and the ends of the both side parts are mutually convex in a direction away from the base part. It is characterized in that it comprises a streamlined dome formed.

The near-infrared absorbing dye is at least one selected from a dimonium compound and a nickel complex.

As described above, according to the present invention, by containing the near-infrared absorber effectively blocking near-infrared, even if exposed to the sun for a long time, the coefficient of linear expansion can be suppressed to less than 3 × 10 ^-5 / ℃ to provide a synthetic wood suitable for quality standards.

As such, the present invention can prevent thermal deformation and greatly increase the durability of the synthetic wood.

1 to 3 are graphs showing absorption wavelength regions according to types of near-infrared absorbing dyes applied to the present invention.
4 is an exploded perspective view illustrating a state in which another synthetic wood deck and railings are installed in one embodiment of the present invention;
FIG. 5 is a perspective view taken to show a cross section of the strut applied to FIG. 4. FIG.

Hereinafter, the synthetic wood for inhibiting thermal expansion according to a preferred embodiment of the present invention will be described in detail.

In the present specification, thermal expansion suppression means that thermal expansion can be reduced so that a change in length per unit length during thermal expansion can be maintained below a predetermined value. Therefore, the synthetic wood of the present invention, it is preferable that the change in length per unit length, that is, the coefficient of linear expansion (coefficient of linear expansion) is less than 3 × 10 ^-5 / ℃.

Synthetic wood according to an embodiment of the present invention is formed by molding a composition for producing synthetic wood. Of course, a conventional synthetic wood production method can be applied as a molding method. For example, a composition in which various materials are mixed in a proportion is extruded into a uniform shape using an extruder. In addition, the composition may be formed by melting the composition into a masterbatch in pellet form and then extruding the masterbatch into a predetermined shape in an extruder.

The composition for producing synthetic wood applied in the present invention contains 35 to 75% by weight of wood powder, 20 to 50% by weight of polyolefin resin, and 2 to 20% by weight of additive.

The wood flour used as the main component of the composition may be a sawdust generated during the cutting of a tree, preferably a branch or a stem of an arbor. Trees (喬木) refers to a plant with a straight stem, thick stems, and clear distinction between trunks and branches. In the present invention, broad-leaved trees and coniferous trees can be used. Since wood flour contains a large amount of moisture in a natural state, it is preferable to go through a drying process to remove moisture. To this end, the wood flour may be dried to a water content of 2 to 5% by weight between drying.

Wood powder is used in the range of 35 to 75% by weight, the strength of the synthetic wood is lowered when the wood powder is less than 35% by weight, and when the content exceeds 75% by weight, the surface of the synthetic wood becomes rough due to excessive wood powder content It is difficult to manufacture high quality synthetic wood. And wood flour is used that the particle size of 50 to 150 mesh (mesh). If the particle size of the wood powder is less than 50 mesh, the mixing property is lowered. If the particle size of the wood powder is more than 150 mesh, the particle size is too small to reduce the strength.

As the polyolefin resin applied to the composition, at least one selected from polystyrene, polypropylene, polyethylene, polycarbonate, and polybutadiene may be used. Preferably polypropylene is used.

The polyolefin resin is contained in 20 to 50% by weight. If the content of the polyolefin resin is less than 20% by weight impact strength is lowered, if the content exceeds 50% by weight it is difficult to obtain a texture such as natural wood.

And the additive contains 2 to 20% by weight. An example of the additive is 1 to 5% by weight mineral, 0.4 to 4% by weight coupling agent, 0.4 to 4% by weight lubricant, 0.2 to 7% by weight stabilizer.

It is preferable to use talc as a mineral. Talc increases smoothness and slows down the expansion caused by humidity. The coupling agent facilitates bonding and solidifies the bonding structure when the wood flour and the polyolefin resin are mixed.

Maleic anhydride, silane, etc. can be used as a coupling agent. In one example, 0.4 to 4% by weight of maleic anhydride is used as the coupling agent. If the content of maleic anhydride is less than 0.4% by weight, the increase in strength is insignificant, and if the content is 4% by weight or more, peeling may occur on the surface of the synthetic wood.

Fatty acids such as stearic acid as a lubricant; And fatty acids amides such as stearic acid amide and oleic acid amide, waxes such as paraffin wax, polyethylene wax, and polypropylene wax, and the like, and may be used alone or in combination of two or more, and are used in an amount of 0.4 to 4% by weight. The lubricating agent smoothes the wood powder so that the wood powder can be pushed out without sticking to the conveying screw during extrusion.

A stabilizer is a substance added in order to prevent or suppress deterioration of resin. The resin deteriorates under the influence of heat, light, and oxygen, and thus needs to be prevented. Types of deterioration include thermal deterioration due to heat, photodegradation due to light and oxygen, and oxidative deterioration.

Stabilizers in the present invention include near-infrared absorbers, preferably near-infrared absorbers, ultraviolet absorbers, and antioxidants. Sunlight, the leading cause of deterioration, transfers heat and light to synthetic wood. Near-infrared rays in the sun cause thermal deformation by rapidly increasing the temperature of synthetic wood by thermal action. Ultraviolet rays have a strong chemical effect, causing photodegradation such as discoloration or discoloration of synthetic wood. And oxygen in the air causes oxidation of synthetic wood.

In the present invention, by using a stabilizer containing a near infrared absorber, it is possible to effectively prevent thermal deformation of the synthetic wood exposed to the sun due to the thermal action. As the near infrared absorber, a material having a maximum absorption wavelength of 800 to 1000 nm is used.

As a preferred near-infrared absorber, a near-infrared absorbing dye is added to a binder in which polymethyl methacrylate is dissolved in NMethyl-2-pyrrolidone.

As the near-infrared absorbing dye, any one or more selected from dimonium compounds and nickel complexes may be applied. The near-infrared absorbing dye effectively absorbs near-infrared in the region of 700 to 1,500 nm.

As an example of the dimonium compound, a compound represented by the following Formula 1 may be used.

As another example of the dimonium compound, a compound represented by the following formula (2) may be used.

In the above formula, R1 is a C3 to C10 linear or branched alkyl group, R2 is a C1 to C10 linear or branched alkyl group, Z is a dialkylsulfonyl imide in which hydrogen of an alkyl group consisting of C1 to C10 is substituted with a halogen group Is selected from the group consisting of pottery or dialkylsulfonyl imido groups, l is an integer from 1 to 2, m is an integer from 2 to 10. Preferably, in Formula 1, R1 is a C4 to C8 linear alkyl group, R2 is a C1 to C6 linear alkyl group, Z is a trifluoromethylsulfonylimido group.

Compared to the dimonium salt monomer, the diionium salt oligomer has an increased molar extinction coefficient without shifting the maximum absorption wavelength, thereby improving near-infrared absorption ability, high compatibility with binder resin, high thermal stability, and high transmittance at high temperature. Less change and excellent durability.

As an example of a nickel complex, a dithiol-based compound represented by the following Chemical Formula 3 or 4 may be used.

Benzotriazole-based 2- (2'-hydroxy-3'-tert-butyl-5'-methyl-phenyl) -5-chlorobenzotriazol may be used as the UV absorber. And 0.1 to 1% by weight of the phosphate-based antioxidants or calcium stearate may be used as the antioxidant.

As the stabilizer in the present invention, two or more of the near-infrared absorber alone or the near-infrared absorber, the ultraviolet absorber, and the antioxidant may be applied. For example, when both the near infrared absorber, the ultraviolet absorbent, and the antioxidant are applied, the total weight of the composition is 0.05 to 3.0 wt% of the near infrared absorber, 0.05 to 3.0 wt% of the ultraviolet absorber, and 0.1 to 1.0 wt% of the antioxidant.

And in this invention, a pigment can be used selectively. Examples of the pigment include inorganic pigments, organic pigments, dyes, and the like. It is preferable to use inorganic pigments because the heat distortion temperature of inorganic pigments is higher than that of organic pigments.

Hereinafter, an embodiment will be described with reference to a method for molding a synthetic wood using the composition.

First, a near infrared absorber is prepared. To this end, a polymethyl methacrylate (polymethyl-methacrylate) is dissolved in NMP (NMethyl-2-pyrrolidone) to prepare a binder solution. Then, any one or more selected from the dimonium compound and the nickel composite is added to the binder solution with a near infrared absorbing dye to uniformly mix to obtain a near infrared absorbent.

Next, 35 to 75% by weight of the prepared wood powder, 20 to 50% by weight of polyolefin resin, 2 to 20% by weight of the additive is mixed to form a composition for producing synthetic wood. At this time, 0.2 to 7% by weight of stabilizer, 1 to 5% by weight of mineral, 0.4 to 4% by weight of coupling agent, and 0.4 to 4% by weight of lubricant are applied.

As a stabilizer, a near infrared absorber may be applied alone. In addition, the stabilizer may be applied by mixing 0.05 to 3.0% by weight of the near infrared absorber, 0.05 to 3.0% by weight of the ultraviolet absorber, 0.1 to 1.0% by weight of the antioxidant as a stabilizer.

The composition is molded into a masterbatch in pellet form after melting using a pellet making extruder. And the masterbatch is extruded to a certain shape in an extruder to form a substrate. After extrusion, the substrate is cooled and the surface of the substrate is polished. Sanding may be applied by the polishing process. After polishing the surface to a certain size to prepare a synthetic wood of the present invention.

Of course, the substrate can be prepared by directly extruding the composition while omitting the master batch molding process in the above-described manufacturing method.

In another embodiment, after the surface polishing, a first coating layer is formed on the surface of the polished substrate. The surface of the substrate is heated to a temperature of 120 to 140 캜 by passing the substrate through a heating apparatus heated to a constant temperature. At this time, the molten resin film is formed on the surface of the substrate while the polyolefin resin contained in the substrate is melted. The substrate on which the molten resin film is formed is passed through a roller to form a first coating layer having a uniform thickness.

After the first coating layer is cured, a near-infrared absorber is applied on the first coating layer to form a second coating layer. It is the same as mentioned in the composition for producing synthetic wood described above as a near infrared absorber. That is, the near-infrared absorbing agent is formed by adding at least one near-infrared absorbing dye selected from a dimonium compound and a nickel composite to a binder in which polymethyl methacrylate is dissolved in NMP. The near-infrared absorber may be applied on the first coating layer by various methods such as spray spraying or bar coater.

The near-infrared absorber is applied and then dried to finally form a second coating layer. After the formation of the second coating layer to cut the substrate to a predetermined size to produce a synthetic wood. In this way, by applying the near-infrared absorber on the outermost surface of the synthetic wood to form a second coating layer can be effectively prevented from penetrating the near-infrared into the interior of the synthetic wood.

Synthetic wood molded as described above has a variety of sizes and shapes depending on the application. Such synthetic wood can be used as various interior and exterior materials of buildings. As an example, a deck structure using synthetic wood is shown in FIG. 4.

Referring to FIG. 4, the deck structure includes a passage part 10 forming a passage through which a person can pass, and a handrail 30 installed at both edges of the passage part 10.

The passage part 10 is formed by coupling a plurality of flooring materials 15 in series. Here, the flooring 15 is an example of the synthetic wood of the present invention. Each flooring material 15 is formed in a plate shape having a constant thickness. A plurality of friction grooves are formed on the top surface of the flooring material 15 to prevent slipping. And both sides of the bottom member 15 is formed with coupling protrusions and coupling grooves, respectively, to be coupled to the adjacent flooring material.

The flooring material 15 may be installed to be supported by the ground or supported by a support frame installed at a predetermined height on the ground.

And handrails 30 are formed on both sides of the passage portion (10). In the illustrated example, the handrail 30 is shown only on one side of the passage part 10, but the same handrail is formed on the opposite side.

The handrail 10 includes a plurality of posts 40 installed at regular intervals, a plurality of crossbars 50 installed horizontally between the posts 40, and the crossbars 50. And coupling means for coupling to 30). The strut 30 and the crossbar 50 are examples of the synthetic wood of the present invention.

Each post 40 has a hollow hollow tubular body 41 and a reinforcing rib 45 protruding from the inner circumferential surface of the tubular body 41 to increase the strength of the tubular body 41. In the illustrated example, the tube 41 is formed in a square, but in addition, it may be formed in various forms such as pentagonal, circular. As shown in FIG. 5, the reinforcing ribs 45 protrude from the inner circumferential surface of the tubular body 41. Reinforcing ribs 45 may be formed in two to three on each side. The reinforcing ribs 45 protrude about 1/10 to 1/8 of the thickness of the tube 41. For example, when the thickness of the tube 41 is 10.5 mm, the protruding length of the reinforcing rib 45 is about 1.05 to 1.31 mm.

The strut 40 is coupled to the fixed frame 60 fixed to the bottom. And the upper end of the support 40 is installed cap 65 for finishing.

Crossbar 50 is installed so that both ends are coupled to the two struts (40). Each crossbar 50 has a hollow hollow tube 51 and a reinforcement portion formed to connect the other inner circumferential surface on one side of the inner circumferential surface of the tubular 51 to increase the strength of the tubular 51.

The tubular body 51 has a base portion 53 which forms a smooth surface, and both side portions 55 formed at both edges of the base portion 53, and are perpendicular to the base portion 53, respectively, It has a streamlined dome portion 57 which interconnects the ends of the side portions 55 and is convex in a direction away from the base portion 53. Thus, the streamlined dome portion 57 can be provided to prevent the safety accident of the pedestrian in advance and to improve the strength of the tube 51.

In addition, the reinforcement part has a first partition wall 61 connected to one side at the center of the base part 53 and the other side connected to the center of the dome part 57 so as to be perpendicular to the base part 53, and the first partition wall ( It is disposed obliquely with 61 and is spaced apart from the first partition 61 on both sides of the first partition 61, the second and third partitions (63) (65) are respectively installed.

On the other hand, it is made of a bracket 70 which is fixed to the side of the support 40 by the coupling means, and a fixing member for fixing the end of the crossbar 50 to the bracket 70. The bolt 73 and the nut 75 are used as the fixing member. The bolt 73 is inserted into the bolt insertion hole 74 formed at the end of the crossbar 50 to pass through the through hole of the bracket 70 and is screwed with the nut 75.

Hereinafter, examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

(Example)

100 mesh particle size 55% by weight of wood powder, 35% by weight of polypropylene, 3.0% by weight of mineral, 2.0% by weight of maleic anhydride as coupling agent, 1.0% by weight of polypropylene wax as lubricant, 1.5% by weight of near infrared absorber, benzoine as ultraviolet absorber Benzotriazole-based 2- (2'-hydroxy-3'-tert-butyl-5'-methyl-phenyl) -5-chlorobenzotriazol 2.0% by weight, 0.5% by weight of calcium stearate as antioxidant 10 minutes at a temperature of about 80 degrees to prepare a composition for producing synthetic wood.

The near-infrared absorber was dissolved in 20 parts by weight of polymethyl methacrylate in NMP to 100 parts by weight of NMPP to form a binder solution, and then 4 parts by weight of near-infrared absorbing dye were added and then mixed uniformly to obtain a near-infrared absorber.

The composition was dried at room temperature after molding a masterbatch in pellet form using a pellet molding extruder. The masterbatch was put into a hopper of a synthetic wood molding extruder to cool the extruded substrate, and then subjected to surface sanding and cutting with a cutter to produce synthetic wood.

Experimental Example 1 Optical Characteristics

In order to examine the optical properties of the near-infrared absorbing dye applied to the above examples, the compounds of Formulas 1, 3, and 4 were used as the first, second, and third test samples.

In order to investigate the optical characteristics of the applied NIR absorbing dyes, the absorption wavelength ranges of three samples were examined using UV-VIS Spectrophotometer (UV-3150, Shimadzu, Japan). 1 to 3 are shown. In the graph, Dye-A, Dye-B, and Dye-C refer to the first, second, and third test samples, respectively. The maximum absorption wavelength (abs.max) is summarized in Table 1 below.

division Absorption wavelength 1st sample 855 nm 2nd test sample 877 nm Third test sample 922 nm

1 to 3, the wavelength band of the near infrared region of 700 to 1000 nm for the first test sample, the near infrared region of 700 to 1100 nm for the second test sample, and the near infrared region of 750 to 1100 nm for the third test sample It can be seen that the absorption effectively. As shown in Table 1, the maximum absorption wavelength was shown at 855 nm for the first test sample, 877 nm for the second test sample, and 922 nm for the third test sample.

From the above results, the composition of the present invention is expected to be able to increase the durability of the synthetic wood by preventing the near-infrared, in particular, the near-infrared ray of 700 to 1100nm effectively prevent the degradation of the synthetic wood by the thermal action of the near infrared.

<Experimental Example 2: Physical Properties>

In order to test the physical properties of the synthetic wood prepared in the above example, the test was commissioned by the Korea Institute of Chemical Fusion Testing. The test results are shown in Table 2 below.

Test Items Basic performance value Results Test Methods Flexural strength 18 or more 25 GR F2016: 2009 Impact resistance There should be no cracks or breaks, and the grooved groove should have a diameter of 15 mm or less. clear GR F2016: 2009 Screw holding force (N) Over 780 825 GR F2016: 2009 Absorption rate (%) Less than 3 0.6 GR F2016: 2009 Length coefficient of thermal expansion (1 / ℃) Less than 3 × 10 ^-5 2.8 × 10 ^-5 GR F2016: 2009 Slip Resistance (BPN) 20 or more 26 GR F2016: 2009 Cold resistance
(-30 ℃) surface clear clear GR F2016: 2009 Flexural strength (N / mm ² ) 16 or more 24 GR F2016: 2009 Moist heat
surface clear clear GR F2016: 2009 Flexural strength (N / mm ² ) 16 or more 23 GR F2016: 2009 Formaldehyde Dissipation (mg / L) maximum 0.4 or less 0.2 KS F3200: 2006 Average 0.3 or less 0.2 KS F3200: 2006 Lead (Pb) (mg / L) 3 or less - Waste Process Test Criteria: 2008 Cadmium (Cd) (mg / L) 0.3 or less - Waste Process Test Criteria: 2008 Hexavalent chromium (Cr6) (mg / L) 1.5 or less - Waste Process Test Criteria: 2008 Copper (Cu) (mg / L) 3 or less 0.018 Waste Process Test Criteria: 2008 Arsenic (As) (mg / L) 1.5 or less - Waste Process Test Criteria: 2008 Mercury (Hg) (mg / L) Less than 0.005 - Waste Process Test Criteria: 2008 Total Volatile Organic Compounds (VOCs) Release (after 7 days) (mg / m ² · h 0.4 or less 0.370 GR F2016: 2009

Referring to the result of Table 2, it can be seen that the result value satisfies the basic performance value in all the test items. In particular, the length of linear thermal expansion coefficient is 2.8 × 10 ^-5 to basic performance value of 3 × 10 ^- were less than ^5. This confirmed that the present invention can effectively prevent the thermal deformation of the synthetic wood.

In the above, the present invention has been described with reference to one embodiment, which is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible.

Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

delete delete delete It is a synthetic wood formed by molding a composition containing 35 to 75% by weight of wood powder, 20 to 50% by weight of polyolefin resin, 2 to 20% by weight of an additive,
The additive contains a stabilizer including a near infrared absorber having a maximum absorption wavelength of 800 to 1000 nm, and the near infrared absorber is a binder solution in which polymethyl-methacrylate is dissolved in NMethyl-2-pyrrolidone. By adding near-infrared absorbing dye to
The synthetic wood is provided with a hollow hollow tube and a reinforcing portion formed to connect the other side of the inner circumferential surface on one side of the inner circumferential surface of the tube to increase the strength of the tube,
The tubular body is formed at both edges of the base part and the base part to form a smooth surface, and both sides are formed at right angles to the base part, and the ends of the both side parts are mutually convex in a direction away from the base part. A thermal expansion inhibiting synthetic wood, characterized in that it comprises a streamlined dome formed. The synthetic wood for inhibiting thermal expansion according to claim 4, wherein the near-infrared absorbing dye is at least one selected from a dimonium compound and a nickel composite.

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