KR102728119B1 - Synthetic wood with improved slip resistance and elasticity and its manufacturing method - Google Patents

Abstract

According to one embodiment of the present invention, a synthetic wood layer includes a thermoplastic resin, wood powder, a binder, a lubricant, a filler, a UV stabilizer, an antioxidant, and a pigment, and a surface layer formed on the surface of the synthetic wood layer to provide slip resistance and elasticity, and a polyethylene and ethylene-1-octene copolymer.

Description

{Synthetic wood with improved slip resistance and elasticity and its manufacturing method}

The present invention relates to a synthetic wood having improved slip resistance and elasticity and a method for manufacturing the same, and more specifically, to a synthetic wood having improved slip resistance and elasticity by adding a surface layer and a method for manufacturing the same.

In general, natural wood is mainly used as interior and exterior materials of buildings, such as flooring, railings, fences, siding, etc. The reason why natural wood is mainly used as interior and exterior materials of buildings is not only because consumer preference is greatly increasing, but also because the natural texture improves the appearance of interior and exterior materials of buildings.

However, natural wood is not only weak to heat, but also has a high absorption rate, so it easily rots and falls off, and when it dries, it warps or cracks, and there are problems such as wear and tear. In addition, natural wood requires long-term preservative treatment to extend its lifespan and maintain its cleanliness, which incurs continuous aftercare costs, and it also causes environmental problems due to forest destruction caused by logging.

Accordingly, research on synthetic wood with functions and appearances similar to natural wood has been actively conducted recently to supplement the weaknesses of wood. These semi-permanent synthetic woods are usually manufactured from a composition that mixes fibers such as wood flour, rice straw, corn stalks, pulp, and rice husks with thermoplastic resins.

Wood Plastic Composite (WPC) is a material that exhibits physical and chemical properties that complement the shortcomings of natural wood. Unlike natural wood, which has a short lifespan, it is durable enough to be used for a long time, and has been used for a long time in industrial fields such as household goods, building materials, and automobile interior materials.

According to the prior art, by blending different thermoplastic resins having different Tgs to impart viscoelasticity, the problem of synthetic wood not being able to escape the thermal properties of the base polymer when a single base polymer is used is resolved, and at the same time, by adding rubber thereto and blending it, the properties are further strengthened to manufacture a ternary composite (TPE) that also exhibits rubber elasticity, thereby creating a synthetic wood that creates new industrial uses.

When mixed throughout the composition to impart elasticity in this way, problems may arise as the strength of the synthetic wood may be reduced due to the flexibility of the material imparting elasticity.

The matters described as background technology above are only intended to enhance understanding of the background of the present invention, and should not be taken as an acknowledgment that they correspond to prior art already known to those skilled in the art.

Patent Registration No. 10-1434095 (August 19, 2014)

The present invention has been made to solve these problems, and the purpose of the present invention is to provide a synthetic wood that has a surface layer formed with a material having a high coefficient of friction and providing elasticity, thereby providing a certain bonding force while imparting slip resistance and elasticity to the surface.

In order to achieve the above object, a synthetic wood according to one embodiment of the present invention includes a synthetic wood layer including a thermoplastic resin, wood powder, a binder, a lubricant, a filler, a UV stabilizer, an antioxidant, and a pigment, and a surface layer formed on the surface of the synthetic wood layer to provide slip resistance and elasticity, and including polyethylene and an ethylene-1-octene copolymer.

The above surface layer may contain 60 to 70 wt% of polyethylene and 30 to 40 wt% of ethylene-1-octene copolymer.

The thickness of the above surface layer can be 7 to 10% of the thickness of the synthetic wood layer.

The thermoplastic resin of the synthetic wood layer may be 20 to 30 wt%, the wood powder may be 50 to 60 wt%, the binder may be 2 to 5 wt%, the lubricant may be 2 to 5 wt%, the filler may be 1 to 4 wt%, the pigment may be 1 to 5 wt%, the antioxidant may be 0.1 to 0.4 wt%, and the UV stabilizer may be 0.1 to 0.4 wt%.

A method for manufacturing synthetic wood according to one embodiment of the present invention includes the steps of melting and mixing a synthetic wood layer including a thermoplastic resin, wood powder, a binder, a lubricant, a filler, a UV stabilizer, an antioxidant, and a pigment through an extruder, the steps of gelling the melted synthetic wood layer, and applying polyethylene and an ethylene-1-octene copolymer to the surface of the gelled synthetic wood layer.

The temperature of the gelation process in the above extruder is 130 to 140°C, and the process of applying the surface layer can be performed by side extrusion at a temperature of 150 to 155°C.

According to the synthetic wood with improved elasticity according to the present invention, the following effects are obtained.

First, it is resistant to external impacts due to its ability to absorb shocks, which is enhanced by the elasticity of the surface layer, so it can reduce the risk of injury when used in children's playgrounds, plazas, etc.

Second, the high friction coefficient of the surface layer improves slip resistance, so when installed on general walkways and around swimming pools, it can prevent accidents caused by slipping.

Third, because of the elasticity of the surface, it can absorb noise, so when used on balconies, terraces, slope decks, etc., it can reduce noise caused by walking.

Fourth, durability can be improved by the surface layer, which can improve the durability of the entire synthetic wood.

Fifth, the surface layer has low thermal conductivity, which can help maintain the surface temperature of the synthetic wood at a constant level.

Figure 1 is a drawing showing a synthetic wood according to one embodiment of the present invention.
Figures 2 and 3 are drawings showing cross-sections of synthetic wood according to one embodiment of the present invention.
FIG. 4 is a drawing showing a synthetic wood according to another embodiment of the present invention.
FIG. 5 is a drawing showing a cross-section of a synthetic wood according to another embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms include the plural forms as well, unless the context clearly dictates otherwise. The word "comprising," as used in the specification, specifies particular features, regions, integers, steps, operations, elements, and/or components, but does not exclude the presence or addition of other particular features, regions, integers, steps, operations, elements, components, and/or groups.

Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.

Hereinafter, a synthetic wood according to a preferred embodiment of the present invention will be described with reference to the attached drawings.

FIG. 1 is a drawing showing a synthetic wood according to an embodiment of the present invention. FIG. 2 and FIG. 3 are drawings showing cross-sections of a synthetic wood according to an embodiment of the present invention. Referring to FIG. 1 to FIG. 3, a synthetic wood according to an embodiment of the present invention has a characteristic configuration in which an elastic layer is formed on the surface, rather than mixing and dispersing rubber or an elastic material throughout the entire synthetic wood to add elasticity above a certain level. If a material adding elasticity to the synthetic wood is dispersed throughout the interior, structural instability may occur in the synthetic wood, which must maintain a certain level of rigidity, due to the flexibility of the material adding elasticity. To overcome this, a surface layer is formed on the surface of the synthetic wood to add a certain amount of elasticity while improving friction on the surface and imparting an anti-slip function.

A synthetic wood (100) according to one embodiment of the present invention includes a synthetic wood layer (110) and a surface layer (120).

The composition of the synthetic wood layer (110) may include a thermoplastic resin, wood powder, a binder, a lubricant, a filler, a UV stabilizer, an antioxidant, and a pigment.

The thermoplastic resin may be an olefin resin, and specifically, may be polypropylene (PP), polyethylene (PE), a copolymer thereof, or a mixture thereof, and preferably, polyethylene alone or a mixture of polypropylene and polyethylene may be used.

Here, the polyethylene may be an ethylene polymer such as high density polyethylene (HDPE), low density polyethylene (LDPE), or linear low density polyethylene (LLDPE). The above olefin resins are more resistant to external impact than other resins, and thus can be used to manufacture high-strength synthetic wood. In particular, the impact strength can be further increased by increasing the content of polypropylene in the olefin resin.

The thermoplastic resin may be included in an amount of 20 to 35 wt%, preferably 20 to 30 wt%, based on the weight of the synthetic wood layer composition.

The thermoplastic resin is preferably polyethylene (pellet).

The above wood flour can be made by crushing recycled materials such as chips, shavings and sawdust into a fine powder, and can be not only pure wood flour but also wood pellets, wood fibers or wood chips, and in some cases, can be used alone or in combination of two or more.

The raw material for the above wood powder can be obtained from conifers or broad-leaved trees. Broad-leaved trees contain more pentosan than conifers, which hinders chemical competition, so conifers may be more effective.

The wood powder may be included in an amount of 50 to 70 wt%, and preferably 50 to 60 wt%, relative to the weight of the synthetic wood layer composition. If the wood powder is less than 50 wt%, the material or function as wood is insufficient, and if it exceeds 60 wt%, the properties as wood are excessively increased, which may cause problems such as reduced strength or rot.

The above binder is used to improve the bonding strength between plastic, i.e., thermoplastic resin, and wood powder. In principle, wood powder exhibits hydrophilic polarity, and plastic exhibits hydrophobic nonpolarity, so the bonding strength between the two substances is weak. Therefore, the interaction between wood powder and plastic is greatly improved by the addition of a binder through a new chemical bond at the interface between the two substances. Such a binder may include maleic anhydride in polyolefin. The binder increases the modulus of rupture (MOR) and modulus of elasticity (MOE) of the composite deck, and helps dimensional stability, impact strength, and dispersion of wood powder. In addition, the binder can enhance anti-fungal properties compared to natural wood by wrapping the wood powder particles with an olefin resin, and can also improve bonding strength. It is preferable that the above-mentioned binder be included in the range of 3 to 5 wt% in the synthetic wood layer composition. If the amount used is less than 3 wt%, the bonding strength cannot be improved, and if it exceeds 5 wt%, it becomes excessive and may deteriorate the physical properties of the synthetic wood.

The above lubricant melts at a certain temperature or higher during extrusion formation and moves to the outside of the synthetic wood, and since the lubricant is coated on the outside of the synthetic wood, it helps to separate the synthetic wood and the extruder during extrusion formation of the synthetic wood and ensures smooth extrusion.

Additionally, the lubricant is a hydrophobic component, which improves water repellency from rainwater, etc.

160℃?, 140℃?의 녹는점을 가지고 있어, 이들의 함량 및 상호 간 비율을 조절함으로써, 용융 시의 흐름성이나 무기필러의 분산성 등을 조절할 수 있다. 바람직하게는, 스테아르산 아연 : 스테아르산 칼슘 : 에틸렌 비스 스테아레이트 = 1 : 0.1 ~ 10 : 0.1 ~ 10인 것이다.The above lubricants include fatty acids such as stearic acid; fatty acid amides such as stearic acid amide and oleic acid amide; waxes such as paraffin wax and polyethylene wax, and more specifically, those selected from zinc stearate, calcium stearate, ethylene bis stearate, and combinations thereof may be used. However, at this time, the type of the lubricant and the mixing thereof should be appropriately designed in consideration of the degree of dispersibility of the inorganic filler during melt extrusion. For example, zinc stearate, calcium stearate, and ethylene bis stearate may be, in order, 120

It has a melting point of 160℃?, 140℃?, and by controlling the content and the ratio thereof, the flowability during melting and the dispersibility of the inorganic filler can be controlled. Preferably, it is zinc stearate: calcium stearate: ethylene bis stearate = 1:0.1 to 10:0.1 to 10.

The above lubricant may be included in an amount of 2 to 5 wt%, and preferably 3 to 4 wt%, relative to the weight of the synthetic wood layer composition. Within the above range, it helps to properly mix the filler and other components, but if it is added in excess, it may interfere with the mixing of raw materials due to the slippery characteristics of fatty acids, and there may be concerns that it may have a negative effect on the physical properties of the synthetic wood.

The above filler absorbs moisture well and exhibits the effect of preventing shrinkage changes on the surface, so it can also help improve strength and formability when manufacturing synthetic wood.

The above filler may be selected from the group consisting of talc, ceramic material, calcium oxide, wollastonite, kaolinite, talc, tungsten and combinations thereof.

The above filler may be included in an amount of 1 to 4 wt%, and preferably 2 to 3 wt%, relative to the weight of the synthetic wood layer composition. Below the above range, the impact resistance of the product cannot be increased and anti-fungal properties cannot be exhibited, and above the above range, not only is the physical properties of the synthetic wood bad, but molding may also become difficult.

As the pigment mentioned above, one or more types of common pigments such as inorganic pigments and organic pigments can be used, but preferably, an inorganic pigment can be used.

The above pigment may be included in an amount of 1 to 5 wt% relative to the weight of the synthetic wood layer composition, and preferably 2 to 3 wt%. If it is less than the above range, it is difficult to express the color, and if it exceeds the above range, the inorganic material causes excessive pressure during the synthetic wood production process, which causes problems in product production.

The antioxidants mentioned above may include, but are not limited to, phosphate-based antioxidants and phenol-based antioxidants. The antioxidants may be included in an amount of 0.1 to 0.4 wt%. Preferably, the amount may be 0.2 to 0.3 wt%. If the amount is less than the above range, problems may arise due to heat resistance generated during the production process, and if the amount is exceeded, the excessively added antioxidants may interfere with molding during the production process.

The above UV stabilizer increases stability against ultraviolet rays, and blocks ultraviolet rays from sunlight to prevent discoloration of the thermoplastic resin. The present invention does not limit the type of the UV stabilizer, and various types known in the field to which this technology belongs can be applied. For example, one or two or more of salicylate-based, benzophenone-based, benzotriazole-based, cyanoacrylate-based, benzoate-based, triazine-based and amine-based UV stabilizers can be used. For example, Poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidinyl]amino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] can be used, but is not limited thereto. The above UV stabilizer may be included in an amount of 0.1 to 0.4 wt%. Preferably, it may be 0.2 to 0.3 wt%. If it is less than the above range, the color of the surface changes when exposed to sunlight, and the surface becomes oxidized and damaged. If it is more than the above range, the excessively added UV stabilizer becomes a factor that interferes with molding during the production process.

Meanwhile, the surface layer (120) includes polyethylene and an ethylene-1-octene copolymer. Basically, it is formed on the surface of the synthetic wood layer by imparting elasticity in the form of a mixture of a polyethylene polymer and an ethylene-1-octene copolymer.

At this time, to explain the formation of the surface layer (120) in more detail, as shown in FIG. 2, a number of unevennesses that serve as non-slip are formed on the surface of the synthetic wood layer (110), and polyethylene and ethylene-1-octene copolymer are applied to the upper surface of the convex portion of the unevenness to form the surface layer (120).

Of course, as shown in FIG. 3, the surface layer (120) may be formed so that when the polyethylene and ethylene-1-octene copolymer is applied to the upper surface of the convex portion of the unevenness, some of it flows toward the inclined surface, thereby wrapping the convex portion except for the groove portion of the unevenness.

By forming such a surface layer on the surface, various effects can be expected. First, by preventing dispersion inside, structural strength can be prevented from being reduced. In addition, by increasing the friction coefficient of the surface, the effect of preventing slipping can be simultaneously exhibited. In terms of recycling, if the elastic material is dispersed throughout the synthetic wood, it may be difficult to recycle, but if it is attached to the surface, the amount is small, so there is almost no deterioration of the physical properties when recycled, and if the surface is removed, reshaped, and then reapplied to the surface, recycling is possible. In particular, recycling of horizontal and cross members of railings is possible.

The surface layer may contain 60 to 70 wt% of polyethylene and 30 to 40 wt% of ethylene-1-octene copolymer in a mixed form of polyethylene polymer and ethylene-1-octene copolymer. When the content of polyethylene is high, there is a problem of reduced elasticity, and when the content of ethylene-1-octene copolymer is low, there is a problem of reduced bonding strength with synthetic wood, so the above range is preferable.

It is desirable that the thickness of the elastic layer be 7 to 10% of the synthetic wood layer. If the thickness of the elastic layer is less than 7%, sufficient elasticity effect cannot be achieved, while if the thickness of the elastic layer exceeds 10%, the economic feasibility may be lowered due to increased cost rather than improved elasticity effect due to increased input.

FIG. 4 is a drawing showing a synthetic wood according to another embodiment of the present invention. FIG. 5 is a drawing showing a cross-section of a synthetic wood according to another embodiment of the present invention. A synthetic wood (200) according to another embodiment of the present invention forms a surface layer (220) on the surface of a hollow inner synthetic wood layer (210) when used as a horizontal member of a railing. In this way, the surface layer (220) can be formed not only on one side of the synthetic wood layer (210), but also on all four sides. The composition of the synthetic wood layer and the surface layer is the same as in the above embodiment.

These features of the present invention can be implemented through the manufacturing method of the present invention.

First, pellets appropriately mixed with thermoplastic resin, wood powder, binder, lubricant, filler, UV stabilizer, antioxidant, and pigment are supplied to the extruder through the hopper. The temperature of the initial region of the extruder is maintained at approximately 210℃, and after passing through the mixing region, the temperature in the intermediate region is maintained at approximately 170℃ while mixing and moving through the extruder. Before forming the surface elastic layer, the temperature of the extruder region is lowered to approximately 135℃ to gel the part formed as the synthetic wood layer.

The surface layer can be formed by supplying the gelled synthetic wood layer to the surface through a side extruder. At this time, the temperature of the extruder in the part where the surface layer is formed is preferably about 150 to 155°C.

By forming a surface layer on the surface of the gelled portion in this way, it is possible to manufacture synthetic wood and add frictional force and elasticity to the surface of the synthetic wood.

The synthetic wood according to one embodiment of the present invention can be used for various purposes due to its elasticity and surface friction. For example, it can be used on walkways where slipping accidents can occur and around swimming pools. In addition, it can prevent impacts, so it can be used in children's playgrounds and plazas to reduce the risk of injury. In addition, when used for railing crossbars, it can improve grip and ensure safety against hand contact.

Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical idea or essential features thereof.

Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

100: Synthetic wood
110: Synthetic wood layer
120: Surface layer

Claims (6)

A synthetic wood layer comprising thermoplastic resin, wood flour, binder, lubricant, filler, UV stabilizer, antioxidant, and pigment; and
A surface layer comprising polyethylene and ethylene-1-octene copolymer, formed on the surface of the synthetic wood layer to impart slip resistance and elasticity,
The above surface layer comprises 60 to 70 wt% of polyethylene and 30 to 40 wt% of ethylene-1-octene copolymer,
A synthetic wood characterized in that the thickness of the surface layer is formed to be 7 to 10% of that of the synthetic wood layer, thereby maintaining the rigidity of the synthetic wood layer while imparting slip resistance and elasticity to the surface layer.
delete delete In claim 1,
A synthetic wood layer characterized in that the thermoplastic resin of the synthetic wood layer is 20 to 30 wt%, the wood powder is 50 to 60 wt%, the binder is 2 to 5 wt%, the lubricant is 2 to 5 wt%, the filler is 1 to 4 wt%, the pigment is 1 to 5 wt%, the antioxidant is 0.1 to 0.4 wt%, and the UV stabilizer is 0.1 to 0.4 wt%. A process of melting and mixing a synthetic wood layer containing thermoplastic resin, wood powder, binder, lubricant, filler, UV stabilizer, antioxidant, and pigment through an extruder.
The process of gelling the above melted synthetic wood layer and
A process for forming a surface layer comprising polyethylene and ethylene-1-octene copolymer on the surface of the above-mentioned gelled synthetic wood layer is included.
The above surface layer comprises 60 to 70 wt% of polyethylene and 30 to 40 wt% of ethylene-1-octene copolymer,
The thickness of the above surface layer is formed to be 7 to 10% of the thickness of the synthetic wood layer.
A method for manufacturing synthetic wood, characterized in that the temperature of the gelation process in the extruder is 130 to 140°C, and the process of forming the surface layer is performed by side extrusion at a temperature of 150 to 155°C.
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