KR102170878B1 - Synthetic wood with high durability - Google Patents

Abstract

The present invention relates to synthetic wood which has excellent durability and mechanical strength, by including wood powder surface-modified with nanocellulose, mineral fibers surface-modified with acrylic, a flame retardant, a first filler, and composite polypropylene.

Description

Synthetic wood with high durability and its manufacturing method {Synthetic wood with high durability}

Synthetic wood with high durability and its manufacturing method {Synthetic wood with high durability}

Natural wood has long been used as a material for building materials, furniture and small items. However, such natural wood has a fatal disadvantage in that deformation such as torsion occurs when exposed to moisture or moisture, and there is a problem in that the production amount is limited.

In order to overcome this problem, plywood such as MDF and HDF has been devised and applied in various ways to furniture and small items at low prices. However, recently, it has been pointed out that such plywood continuously discharges substances that are lethal to the human body, and accordingly, may pose a danger to various places of the human body as well as the skin.

In order to devise such a problem, the demand and manufacture of synthetic wood manufactured by mixing a thermoplastic polymer and wood powder are increasing. However, such synthetic wood has a relatively low wear resistance and mechanical strength due to the thermoplastic polymer, and also has a problem that cracks and cracks occur due to low bonding strength between wood powder and polymer during long-term use because wood powder and resin cannot be mixed uniformly. have.

Korean Patent Publication No. 10-1920386

An object of the present invention is to provide a durable synthetic wood.

Another object of the present invention is to provide a synthetic wood having flame retardancy.

Another object of the present invention is to provide a synthetic wood having excellent mechanical strength.

The synthetic wood according to the present invention includes wood powder surface-modified with nanocellulose, mineral fibers surface-modified with acrylic, flame retardant, first filler, and composite polypropylene.

In the synthetic wood according to an embodiment of the present invention, the nanocellulose may be characterized in that it has a fiber shape having a cross-sectional diameter of 5 to 50 nm and a length of 50 to 400 nm.

In the synthetic wood according to an embodiment of the present invention, the wood powder may be characterized in that it is first surface-modified with nanocellulose and secondary surface-modified with a vinylsilane surface modifier containing a vinyl group at the terminal.

In the synthetic wood according to an embodiment of the present invention, the mineral fiber is one or more selected from silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), iron dioxide (Fe ₂ O ₃ ), and alkaline earth metal oxides. It may include.

In the synthetic wood according to an embodiment of the present invention, the mineral fibers may have an average cross-sectional diameter of 0.2 to 2 mm and an average length of 20 to 100 mm.

In the synthetic wood according to an embodiment of the present invention, the composite polypropylene may include an ethylene-propylene copolymer, a polypropylene, an ethylene-octene copolymer, and maleic anhydride.

In the synthetic wood according to an embodiment of the present invention, the flame retardant may be characterized in that the phosphorus-based flame retardant.

Synthetic wood according to an embodiment of the present invention is 20 to 60 parts by weight of composite polypropylene, 5 to 20 parts by weight of acrylic surface-modified mineral fiber, 10 to 30 parts by weight, based on 100 parts by weight of the nanocellulose-modified wood flour. It may contain a first filler, 2 to 15 parts by weight of a flame retardant.

By including wood powder surface-modified with nano cellulose, mineral fibers surface-modified with acrylic, flame retardant, first filler and composite polypropylene, it exhibits flame retardancy, and has excellent durability and mechanical strength.

Advantages and features of the embodiments of the present invention, and a method of achieving them will become apparent with reference to the embodiments described later in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and are common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

The synthetic wood according to the present invention includes wood powder surface-modified with nanocellulose, mineral fibers surface-modified with acrylic, flame retardant, first filler, and composite polypropylene.

Synthetic wood according to the present invention contains wood powder surface-modified with nanocellulose, mineral fibers surface-modified with acrylic, flame retardant, and composite polypropylene, so that it has excellent compatibility between the constituents of the synthetic wood and does not cause cracking even after long-term use. There are no advantages.

The synthetic wood according to the present invention includes wood powder surface-modified with nanocellulose. There is an advantage in that the mechanical strength improvement effect of the whole synthetic wood can be exhibited by using wood powder that has been surface-modified with nanocellulose instead of general wood powder.

At this time, nano cellulose refers to nanoparticles of cellulose derived from wood, agricultural by-products, and bacteria by mechanical or chemical methods. Specifically, mechanical pulverization may include a refining method using a refiner, a high pressure homogeneous method manufactured by passing a small nozzle at high pressure, and a freezing pulverization method in which cellulose swollen in water is frozen with liquid nitrogen and then pulverized. Acid hydrolysis or enzymatic treatment can be used. In the nanocellulose, the raw material of cellulose and the method of nanoparticles do not affect the scope of the present invention, and the present invention is not limited by the raw material of cellulose and the method of nanoparticles.

In the synthetic wood according to an embodiment of the present invention, the nanocellulose may have a cross-sectional diameter of 10 to 50 ㎚ and a length of 50 to 400 ㎚, and by satisfying this range, the binding force with wood powder is increased, and excellent mechanical strength is improved. There is an advantage that can be expressed.

In the synthetic wood according to an embodiment of the present invention, the wood powder surface-modified with nanocellulose may be surface-modified with a first surface-modified nanocellulose and a secondary surface-modified with a vinylsilane surface-modifying agent containing a vinyl group at the terminal. By passing through such a secondary surface modification step, a number of vinyl groups are included on the surface of the surface-modified wood flour, and as a result, there is an advantage of remarkably improving the compatibility with the mineral fibers surface-modified with composite polypropylene and acrylic. . Further, in the synthetic wood according to an embodiment of the present invention, nanocellulose is added in a method of surface modification to wood flour rather than a separate composition, thereby blocking aggregation by the hydrophilicity of the nanocellulose itself and inducing uniform dispersion of the nanocellulose. Yet, there is an advantage of improving the compatibility with other compositions by the surface vinyl group.

At this time, the vinylsilane surface modifier containing a vinyl group at the end can be used without limitation if it is an alkoxysilane compound containing a vinyl group at the beginning, but specifically, the vinylsilane surface modifier is vinyl trimethoxysilane and vinyl triethoxy It may be one or two or more selected from silane, but the present invention is not limited thereto.

The synthetic wood according to the present invention contains mineral fibers. By including these mineral fibers, the strength such as compressive strength and flexural strength of the synthetic wood can be remarkably enhanced, and thus durability improvement effects can be expected.

At this time, the mineral fiber may be an artificial mineral fiber other than natural mineral fiber such as asbestos for safety, and the present invention is not limited thereto. As a specific and non-limiting example, the artificial mineral fiber is made of one or more compounds selected from silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), iron dioxide (Fe ₂ O ₃ ), and alkaline earth metal oxides. It may be a manufactured artificial mineral fiber.

More preferably, the mineral fiber may have a cross-sectional diameter of 0.2 to 2 mm, preferably 0.5 to 1.5 mm, and an average length of 20 to 100 mm. If the size of the mineral fibers is too small, aggregation between the mineral fibers may occur, and if the size of the mineral fibers is too large, problems such as desorption of the mineral fibers may occur.

In the synthetic wood according to an embodiment of the present invention, the mineral fiber is characterized in that the surface is modified with acrylic. In the aspect of the manufacturing method, the surface-modified mineral fiber with the acrylic resin includes a first step of surface-modifying the mineral fiber with a surface modifier including an acrylic group or a methacrylic group; A second step of mixing the surface-modified mineral fiber with the acrylic monomer and a thermal initiator in the first step; after preparing an acrylic mixture including, mixing it with other compositions and extruding, acrylic polymerization is performed by a thermal initiator As a result, synthetic wood may be included in the form of mineral fibers surface-modified with acrylic resin.

By including the mineral fiber surface-modified with such an acrylic resin, the compatibility between the mineral fiber and other composite polypropylene can be remarkably improved, and the even distribution of the mineral fiber can exhibit a more excellent strength improvement effect, and long-term friction or impact There is an advantage that can prevent the desorption of mineral fibers by.

Specifically, the surface modifier including an acrylic group or a methacrylic group at the terminal may be preferably used without limitation if it includes an acrylic group or methacrylic group at the terminal of the siloxane-based compound. Preferably, the surface modifier containing an acrylic group or a methacrylic group is 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, 3-methacrylic It may be one or two or more selected from acryloxypropyl triethoxysilane and 3-acryloxy trimethoxysilane, but the present invention is not limited thereto.

In addition, the acrylic monomer mixed in the second step can be used without limitation if it is a monomer that is typically used for polymerization of an acrylic resin, and the present invention is not limited thereto. As a specific and non-limiting example, the acrylic monomer is methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate , t-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl ( It may be one or two or more selected from meth)acrylate and isobornyl (meth)acrylate, but the present invention is not limited thereto.

Specifically, the weight ratio of the surface-modified mineral fiber: acrylic monomer mixed in the second step may be 1:0.8 to 1.5, and in this range, it is possible to induce sufficient polymerization on the surface of the mineral fiber and exhibit excellent compatibility improvement effect. There is an advantage.

In addition, the type of the thermal initiator mixed in the second step can be used without limitation, if it is a thermal initiator that can be used for polymerization of acrylic, and the present invention is not limited thereto. As a specific and non-limiting example, the thermal initiator is an azo initiator, peroxy ester initiator, acyl peroxide initiator, peroxy dicarbonate initiator, ketone peroxide initiator, dialkyl peroxide initiator, peroxy ketal initiator. One or two or more selected from an initiator and a hydroxy peroxide-based initiator may be used, but the present invention is not limited thereto. The amount of the thermal initiator added may be 0.5 to 3 parts by weight based on 100 parts by weight of the acrylic monomer, but the present invention is not limited thereto.

Synthetic wood according to an embodiment of the present invention may include 5 to 20 parts by weight, preferably 8 to 15 parts by weight of the surface-modified mineral fibers with acrylic based on 100 parts by weight of the wood flour surface-modified with nano cellulose. When the content of the mineral fiber surface-modified with acrylic is low, it is difficult to exhibit the effect of improving strength, and when the content of the mineral fiber is high, mineral fiber aggregation may occur.

Synthetic wood according to the present invention includes a composite polypropylene, and by using a polypropylene binder, there is an advantage of providing chemical resistance, water resistance, and improved mechanical strength compared to the case of using other polyolefin resins.

In addition, the composite polypropylene includes ethylene-propylene copolymer, ethylene-octene copolymer, and maleic anhydride in addition to polypropylene, and contains ethylene-propylene copolymer and ethylene-octene copolymer, compared to the case of using polypropylene alone. There is an advantage that can significantly improve impact resistance.

In terms of manufacturing method, the synthetic wood may be extruded by mixing a composite polypropylene master batch during extrusion. The ethylene-propylene copolymer and the polypropylene contained in the composite polypropylene have 20 to 40 g/10 min (190° C. 2.16 kg), and the ethylene-octene copolymer has 0.99 g/10 min. To do.

As described above, the ethylene-octene copolymer may be mixed with the composite polypropylene to increase impact resistance. During molding, the components of the composite polypropylene resin may not be uniformly mixed due to poor compatibility, and defects may occur. Accordingly, maleic anhydride may be included as a compatibilizing agent in order to increase the miscibility and compatibility of the ethylene-propylene copolymer, polypropylene, and ethylene-octene copolymer.

In the synthetic wood according to an embodiment of the present invention, the composite polypropylene is an ethylene-propylene copolymer 50 to 80% by weight, polypropylene 3 to 20% by weight, ethylene-octene copolymer 5 to 30% by weight, and maleic anhydride 0.1 It may contain to 0.8% by weight, and satisfies such a composition to facilitate molding during extrusion, and has an advantage of exhibiting excellent durability compared to conventional synthetic wood.

Synthetic wood according to an embodiment of the present invention may contain 20 to 60 parts by weight, preferably 40 to 55 parts by weight of composite polypropylene, based on 100 parts by weight of the wood powder surface-modified with the nano cellulose, and a small amount of composite polypropylene When included, it is difficult to secure water resistance, and when a large amount of composite polypropylene is included, it may cause a decrease in compressive strength and flexural strength.

The synthetic wood according to an embodiment of the present invention may secure flame retardancy by including a flame retardant. At this time, the flame retardant may be selected from halogen-based, phosphorus-based, and inorganic-based, and preferably, a phosphorus-based flame retardant may be included. Specifically, the phosphorus-based flame retardant may include an inorganic phosphorus-based flame retardant such as ammonium phosphate and an organic phosphorus-based flame retardant such as trioctyl phosphate, but the present invention is not limited thereto.

The synthetic wood according to an embodiment of the present invention may contain 2 to 15 parts by weight of a flame retardant based on 100 parts by weight of the nanocellulose. If the flame retardant is included in a small amount, the flame retardant effect is significantly lowered, and if a flame retardant is included in a large amount, durability may be deteriorated.

The synthetic wood according to an embodiment of the present invention includes a first filler, and a certain level of hardness or higher can be secured by such a filler. Specifically, the first filler may be one or two or more selected from calcium carbonate, barium sulfate, and talc, but the present invention is not limited thereto.

Specifically, the synthetic wood according to an embodiment of the present invention may contain 10 to 30 parts by weight of a filler based on 100 parts by weight of the nanocellulose. When a small amount of the filler is included, it is difficult to exhibit the effect of improving the hardness, and a problem of lowering the water resistance including a large amount of the filler may occur.

Hereinafter, the present invention will be described in detail by examples and comparative examples. The following examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited by the following examples.

[Production Example 1]

1. Preparation of wood powder surface-modified with nanocellulose

1 kg of wood flour having an average particle diameter of 70 μm was completely dried to prepare, and 50 g of nanocellulose was added to 1 kg of water and stirred to prepare a nanocellulose surface modifier solution. At this time, the nanocellulose has an average cross-sectional diameter of about 50 nm and a length of 250 nm, and cellulose derived from wood was used.

1 kg of dried wood flour was added to the prepared nano cellulose surface modifier solution, stirred for 1 hour, and then the surface modifier solution was removed and secondary drying was performed to prepare a primary surface-modified wood flour. Thereafter, 10 g of Vinyltrimethoxysilane was added to 500 g of ethanol and stirred uniformly to prepare a vinylsilane surface modifier solution. The first surface-modified wood powder was added to the prepared vinylsilane surface modifier solution and stirred for 2 hours, and then the ethanol solution was removed and dried to finally prepare the surface-modified wood powder.

2. Preparation of acrylic mixture

Mineral fibers having an average cross-sectional diameter of 0.9 mm were prepared through a mineral fiber maker, and then cut to have an average length of 50 mm to prepare mineral fibers. At this time, the mineral fiber was prepared in a mixture of 55% by weight of silicon dioxide, 20% by weight of aluminum oxide, 5% by weight of iron dioxide, 10% by weight of calcium oxide, and 10% by weight of magnesium oxide.

In a solution of 1000 ml of ethanol and 100 ml of water, 50 g of 3-methacryloxypropyl methyldiethoxysilane was mixed and stirred for 20 minutes to perform a hydrolysis reaction, and 1 kg of the prepared mineral fiber was added to the surface while stirring at 55°C for 2 hours. The reforming reaction was carried out. Thereafter, the mineral fibers were separated and dried at 40° C. for 12 hours to prepare a mineral fiber surface-modified with acrylic silane.

60 g of isobornyl acrylate was mixed and stirred for 30 minutes, and a total of 45 g was added by dividing 3 g of the mineral fiber surface-modified with acrylic silane into 15 times, and di-3-methoxybutyl peroxide as a thermal initiator. A mineral fiber surface-modified with acrylic was prepared by mixing 2 g of CD carbonate.

3. Preparation of composite polypropylene pellets

64.5% by weight of ethylene-propylene copolymer with a melt index of 25 g/10min, 15% by weight of polypropylene with a melt index of 20 g/10min, 20% by weight of an ethylene-octene copolymer with a solubility index of 0.9 g/10min, and male anhydride After mixing and melting 0.5% by weight of ic acid, it was stirred for 2 hours, cooled, and pulverized to prepare composite polypropylene pellets.

4. Manufacture of synthetic wood

1000 g of wood powder surface-modified with nano cellulose, 455 g of composite polypropylene pellets, 136 g of acrylic mixture containing mineral fibers, 273 g of calcium carbonate filler with an average particle diameter of 30 µm, tricresyl phosphate 90 g as a flame retardant, antioxidant 1,3,5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene 8 g, UV stabilizer 2-[2-hydroxy-3,5-di -(1,1-dimethylbenzyl)]-2H-Benzotriazole 8 g and colored pigment 45 g were added to the auxiliary extruder to extrude the synthetic wood.

[Production Examples 2 to 6]

Prepared in the same manner as in Preparation Example 1, but synthetic wood was prepared with the same composition as in Table 1 below, except that the description of antioxidants, ultraviolet stabilizers and pigments in Table 2 were omitted, and all were put in the same composition as in Preparation Example 1. I did. All display units in Table 2 are g.

Manufacturing example Wood flour Polypropylene pellets Mineral fiber Filler Flame retardant One 1000 455 136 273 90 2 1000 485 125 300 85 3 1000 195 136 273 90 4 1000 620 136 273 90 5 1000 455 45 273 90 6 1000 455 220 273 90

[Production Example 7]

It was prepared in the same manner as in Preparation Example 1, but the surface treatment using vinyl silane was omitted during the manufacturing process of the wood powder surface-modified with nano cellulose to prepare wood powder, and a synthetic wood was manufactured using this.

[Production Example 8]

It was prepared in the same manner as in Preparation Example 1, but the process of modifying the surface of the nanocellulose wood powder was omitted and the surface was treated with only vinyl silane to prepare a synthetic wood.

[Production Example 9]

It was prepared in the same manner as in Preparation Example 1, but was directly mixed without applying a separate surface treatment to the mineral fiber to prepare a synthetic wood.

Check impact strength

In accordance with KS M ISO 179-1, a notch-free test piece was used and the composite wood was hit to measure, and the average value of the five test pieces was calculated and shown in Table 2.

Weatherability check

Under the conditions of KS M ISO 4892-2, the composite wood was tested for up to 2000 hours (340 nm, 0.55 w/m ² ) and the impact strength was tested, and the rate of change compared to the initial impact strength was calculated as %, and the results are shown in Table 2. Done.

Moisture absorption rate check

The synthetic wood prepared in each Preparation Example was allowed to stand for 48 hours in an environment of 65% relative humidity at 20°C to form a stable state. Thereafter, the test piece was immersed in water at 90° C. for 3 hours, immediately transferred to water at 20° C., cooled completely, dried, and the mass difference was measured, and the mass change rate was calculated and shown in Table 2.

Mass change rate (%)=[(mass after immersion)-(mass before immersion)]/(mass before immersion)×100

Impact strength (kJ/m ² ) Weather resistance (%) Water absorption rate (%) Manufacturing Example 1 3.0 98 2.3 Manufacturing Example 2 3.1 98 2.3 Manufacturing Example 3 1.8 87 6.4 Manufacturing Example 4 2.4 99 2.1 Manufacturing Example 5 2.2 95 2.7 Manufacturing Example 6 2.7 92 3.1 Manufacturing Example 7 2.2 82 4.5 Manufacturing Example 8 2.5 88 3.8 Manufacturing Example 9 2.6 95 3.2

Referring to Table 2, in Preparation Example 1 and 2 containing wood powder surface-treated with nanocellulose and vinylsilane surface modifier, mineral fiber surface-modified with acrylic, flame retardant, filler, and composite polypropylene, the impact strength was high, and the weather resistance was It can be seen that it is excellent and has a low moisture absorption rate.

Claims (8)

Including the primary surface modification of nano cellulose and wood powder secondary surface modification with a vinyl silane surface modifier containing a vinyl group at the terminal, mineral fibers surface-modified with acrylic resin, flame retardant, first filler and composite polypropylene,
The surface-modified mineral fiber with the acrylic resin is a first step of surface-modifying the mineral fiber with a surface modifier containing an acrylic group or a methacrylic group at the terminal; It is manufactured including; a second step of mixing the surface-modified mineral fiber, the acrylic monomer, and a thermal initiator in the first step,
20 to 60 parts by weight of composite polypropylene, 5 to 20 parts by weight of acrylic surface-modified mineral fiber, 10 to 30 parts by weight of a first filler, and 2 to 15 parts by weight of a flame retardant relative to 100 parts by weight of the nanocellulose surface-modified wood flour. Synthetic wood comprising a. The method of claim 1,
The nanocellulose is synthetic wood, characterized in that the cross-sectional diameter is 5 to 50 ㎚, the length is 50 to 400 ㎚ fiber shape. delete The method of claim 1,
The mineral fiber is a synthetic wood containing one or two or more selected from silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), iron dioxide (Fe ₂ O ₃ ) and alkaline earth metal oxide. The method of claim 1,
The mineral fiber is synthetic wood, characterized in that the average cross-sectional diameter is 0.2 to 2 ㎜, the average length is 20 to 100 ㎜. The method of claim 1,
The composite polypropylene is synthetic wood comprising an ethylene-propylene copolymer, polypropylene, an ethylene-octene copolymer, and maleic anhydride. The method of claim 1,
Synthetic wood, characterized in that the flame retardant is a phosphorus-based flame retardant. delete