KR101062659B1 - Composite wood composite material containing bamboo wood powder and its manufacturing method, synthetic wood produced using the same - Google Patents

Abstract

The present invention relates to a composite material for synthetic wood containing bamboo wood powder, and a method for manufacturing the same, a synthetic wood produced using the same, which is a natural resin matrix mainly composed of a high content of bamboo wood flour and HDPE resin, and has weatherability and durability. We have developed a composite with excellent performance, which has excellent physical and chemical properties such as water resistance, solvent resistance, and scratch resistance, and has low weight to strength. Synthetic wood by the composite material has the additional advantage of easy formability and low manufacturing cost, as well as excellent surface gloss and can express the texture of natural wood, is produced by the eco-friendly material of the unique scent of bamboo .

Composite wood composite material according to the present invention is (a) 45 to 65% by weight of cellulose fibers prepared from bamboo wood flour, (b) 20 to 40% by weight of HDPE resin, (c) UV stabilizer, flame retardant, binder, antistatic agent, It is characterized in that it consists of 10 to 20% by weight of additives containing at least one of a plasticizer, a filler, an antioxidant, a colorant, a lubricant, a heat stabilizer, and an antibacterial agent. The bamboo wood flour is a cellulose fiber having a length of 4 mm or less reacted with carbon disulfide and contains lignin and wax, and the HDPE resin may be a new resin or a recycled resin.

Composite or synthetic wood according to the present invention can be applied in various forms, such as building interior and exterior materials, replacement of CCA preservatives, outdoor decks, pergola, bench interiors and other decorative structures.

Bamboo wood flour, cellulose fiber, carbon disulfide, sodium hydroxide, HDPE resin, synthetic wood

Description

Composition materials for synthetic wood comprising bamboo fibers and its preparation process, a synthetic wood manufactured by it}

The present invention relates to a composite wood composite material containing a bamboo wood powder, and a method for manufacturing the same, and a synthetic wood produced using the same, weather resistance and durability by a natural resin matrix mainly composed of a high content of bamboo wood powder and HDPE resin We developed composite materials with excellent physical and chemical properties such as water resistance, solvent resistance, and scratch resistance, and having low weight to strength. It is used in various forms in facilities and decorative structures such as replacements, outdoor decks, pergola and bench interiors.

The deck wood and the wood table, which make the rural landscape look more natural and look more natural, are actually impregnated with very little. The wood we often use for deck materials is Hem-lock, a pine species. Inner hemp (Hem-fir) is mainly used as the material of the wood is a material of the wood of the type of pine (American pine).

'Preserving wood' is produced by the so-called preserving wood as the general wood undergoes the preservative treatment process, and the CCA (Cromated Copper Arsenate) preserving wood is a name that refers to the preserving wood after the chromium copper arsenate treatment process. Alkaline Copper Quaternary (ACQ) preservatives, or alkaline copper ammonia compounds, which are used in the mainstream market to protect lumber from corrosion and decay, and from ants such as arsenic and chromium. Preserved wood was developed. In the United States and Canada, ACQ treated wood is used instead of CCA treated wood for residential purposes, and copper, which is the main component of ACQ, has a firm position as an effective insecticide in wood preservatives. It is highly likely to be in the spotlight due to eco-friendly trends, but so far, ACQ and CCA can be used differently depending on the required conditions and situations.

However, when looking at the domestic distribution market, almost all imported and domestically produced CCA-treated preservatives, ACQ is rarely produced domestically, and imports are not much. Moreover, ACQ and CCA treated preservatives are not easy to distinguish from each other.

Preservatives are literally drugs that do not decay, so they refuse to contain highly toxic substances because their purpose is to block the microbial habitat, which is the root cause of the decay, and to kill insects that eat wood. It can't be true. Therefore, the amount of preservatives impregnated with the surface of the splint is small, but it is very likely to contaminate the garden water, such as flowers inhabiting the human body as well as the surrounding soil and nearby as it leaks out.

The path through which people are exposed to preservatives is as follows:

1. In direct contact with the splint

2. Indirect contact with surrounding soil, water and air, etc.

3. Especially if you spend a long time in outdoor facilities such as playgrounds, rural houses or pensions

In these situations, particularly the damage of children, children, and pets, especially in infants, is likely to be more or less severe in the long run or in the short term, and one of the ways to reduce the damage of these splints is to paint regularly with permeable oil stains so that moisture This will prevent the leakage of preservatives by delaying the dissolution of the preservatives, and inhalation of smoke can be very harmful when burning the remaining splinter materials. As a result, sawdust, which is a byproduct, is very harmful and should not be inhaled if possible, and the remaining ash after burning sawdust or wood should not be used for composting edible crops or left in the yard. Serious damage to the health and environment of the Is a situation that continues to release the report.

As such, the substances contained in the outdoor camping material contain chromium, arsenic, copper, etc., which release harmful poisons to nature and human body.

To replace the CCA wood veneer, WPC (Wood Plastic Composite) using wood powder has been used as a synthetic wood, but this also exposes the physical and physical disadvantages such as surface hardness, screwing detachment, and deterioration due to temperature change. In order to reinforce chemical properties and make environmentally friendly products, composite materials in which wood powder is mixed with LDPE (low density polyethylene), PP (polypropylene), PS (polystyrene) or PVC (polyvinyl chloride) resins have been generally used.

However, the general-purpose resins have a disadvantage in that the surface hardness is weak after molding and excessive shrinkage (more than 2 to 3%) occurs due to the change of temperature, and in order to increase the bonding strength with the resin because the wood powder itself lacks viscosity. The moldability which can be molded as a resin composition only arises when the mixing ratio of resin and wood powder is at least 1: 1 weight ratio.

Virtually all synthetic wood (WPC) uses wood powder rather than wood fiber, which is made by crushing recycled materials such as chips, shavings and sawdust into fine powder, which is more difficult to process than wood powder. Wood fibers often have good composite properties and are often used as reinforcing agents rather than as fillers.

On the other hand, the cellulose obtained from ordinary wood is a microfiber that determines its properties as a reinforcing agent and is kraft pulp from which lignin and wax have been removed, or a thermomechanical pulp containing lignin or wax, depending on its treatment method. It can be manufactured.

An object of the present invention is to extract cellulose fibers having excellent binding strength by using bamboo wood flour instead of simple wood flour. By mixing with the resin, coalescence and creaming flocculation is increased, so extrusion molding is possible even with a small resin content. To provide a composite wood composite material having excellent chemical properties, and a method of manufacturing the same. Originally, bamboo has a higher hardness than other woods, so after molding synthetic wood, it has excellent properties in hardness, bending strength, tensile strength, water resistance, and heat resistance.

It is another object of the present invention to prepare synthetic wood by using a composite material whose main component is bamboo wood powder in a thermoplastic resin composed of hard HDPE (High Density Polyethylene). Excellent physical and chemical properties such as embrittlement and scratch resistance, low weight and formability compared to strength, low manufacturing cost, and excellent surface smoothness. Through surface treatment is easy to express the texture of natural wood as well as to provide a synthetic wood with a unique bamboo scent.

Composite wood composite material according to the present invention is (a) 45 to 65% by weight of cellulose fibers prepared from bamboo wood flour, (b) 20 to 40% by weight of HDPE resin, (c) UV stabilizer, flame retardant, binder, antistatic agent, A plasticizer, a filler, an antioxidant, a colorant, a lubricant, a heat stabilizer, and an antibacterial agent containing 10 to 20% by weight of additives containing at least one of them is characterized in that it is composed of. The cellulose fiber is produced by reacting bamboo wood powder with carbon disulfide (CS ₂ ), and then washing it 1 to 5 times with an aqueous sodium hydroxide solution at room temperature to neutralize and desulfurize and dry it to a water content of 8% or less. Cellulose fiber having a length of, contains lignin and wax, and HDPE resin is more preferable in terms of environmental protection, using recycled resin made by collecting and washing waste scrap of various waste HDPE products as well as new resin. .

In addition, by preparing a composite material mixed with various chemical additives in the cellulose fiber and HDPE resin prepared from the bamboo wood powder, molded into a pellet (PELLET) shape through extrusion molding, and then cooled to a synthetic wood through a mold It is characterized by producing a usable finished product.

According to the present invention, by using the bamboo wood powder instead of simple wood powder to extract the cellulose fibers with excellent binding force by itself By mixing with resin, coalescence and creaming flocculation is increased, so extrusion molding is possible even with a small resin content. It has a low weight, and is excellent in formability and dimensional stability of the product and low in manufacturing cost.

The present invention is a synthetic wood manufactured using a composite material containing a high content of bamboo wood powder and a hard HDPE thermoplastic resin, the weather resistance and durability, water resistance, heat resistance, solvent resistance and scratch resistance due to the surface hardness of the product, Physical and chemical properties such as flexural strength, tensile strength, screw and nail bonding strength are superior to any conventional natural wood or synthetic wood, and the synthetic wood contains lignin and vegetable wax in cellulose fibers, resulting in surface gloss and texture. Not only this, but also excellent surface smoothness, it is easy to surface treatment by surface friction sand paper machine after extrusion molding or to form wood grain pattern by pressure roller method, so that the texture of natural wood can be expressed. There is a beneficial effect of inherent fragrance.

Composite or synthetic wood according to the present invention can be applied in various forms, such as building interior and exterior materials, replacement of CCA preservatives, outdoor decks, pergola, bench interiors and other decorative structures.

The present invention is a means for solving the technical problem, (a) 45 to 65% by weight of cellulose fibers made from bamboo wood flour, (b) 20 to 40% by weight of HDPE resin, (c) UV stabilizer, flame retardant, binder, It is a composite wood composite material composed of 10 to 20% by weight of additives containing at least one of antistatic agents, plasticizers, fillers, antioxidants, colorants, lubricants, heat stabilizers, antibacterial agents. The cellulose fiber is produced by reacting bamboo wood powder with carbon disulfide (CS ₂ ), and then washing it 1 to 5 times with an aqueous sodium hydroxide solution at room temperature to neutralize and desulfurize and dry it to a water content of 8% or less. It is a fiber having a length of and contains lignin and wax by itself, and it is more economical and environmental to use recycled resin prepared by collecting and washing waste pellets of various waste HDPE products as well as new resin. It is preferable in terms of.

Next, a composite material obtained by mixing various chemical additives together with the cellulose fiber and HDPE resin prepared from the bamboo wood flour was molded into a pellet shape through extrusion molding, cooled, and then synthesized through an extrusion, injection, compression molding machine, or the like. Manufacture wood.

In the following, preferred embodiments of the present invention and the operation of each component in detail, which is intended to illustrate to the extent that the invention can be easily carried out by those skilled in the art to which the present invention pertains, It is not intended that the technical spirit and scope of the present invention be limited.

In the present specification, 'bamboo wood flour' is a particle crushed to a size of 20 to 50 mesh, and the ratio of length to diameter is about 5: 1 or less is preferable in view of formability and product strength. The bamboo wood flour must be reacted with carbon disulfide (CS ₂ ) to extract the cellulose microfibers having a length of 4.0 mm or less, in order to increase its viscosity, which is lignin as a fiber sodium cellulose xanthate. And wax.

[cellulose-RONa + CS ₂ → cellulose-RO (CS) Na]

It is neutralized and desulfurized by washing with dilute sodium hydroxide solution to remove residual toxicity of carbon disulfide and dried to reduce the moisture content of the material. At this time, the moisture content is preferably 8% or less for the purpose of improving the bondability with the resin.

Thus, the cellulose fiber (a) prepared from bamboo wood flour contains 45 to 65% by weight relative to the total weight of the composite material, and contains 1 to 3 times or more weight ratio of the HDPE resin (b) to 20 to 40% by weight. The stability is superior to that of general synthetic wood (WPC), and also has excellent effects on physical and chemical properties and textures such as strength and surface properties, water and heat resistance, and bamboo fragrance generation.

In addition, the resin component used in the present invention is an HDPE resin having a density of 0.940 g / cm 3 or more (0.940 to 0.980 g / cm 3), which is finally selected so that LDPE, PP, Compared with general-purpose resins such as PS or PVC resin, the bonding strength with bamboo wood powder is strengthened, and even though HDPE resin is used in general synthetic wood, wood powder is used as a filler in general synthetic wood as it is. There is a serious problem of poor binding with a high density HDPE resin, which eventually results in failure to obtain desirable physical properties as synthetic wood.

In general, HDPE resin is structurally high in crystallinity and very low in tertiary H, so it is more stable against oxidation than other polyolefins, and it is a common organic solvent up to 60 ° C under no stress. It shows extremely stable properties against acid, alkali and the like.

The above-mentioned HDPE resin is collected, washed and melted from waste HDPE products in consideration of economic and environmental considerations, and then used as a recycled resin made of pellets alone or mixed with an appropriate amount of fresh resin. More advantageous effects can also be obtained.

Next, the component and the function of the auxiliary material added by this invention are demonstrated in detail below.

The additive subsidiary material (c) is preferably mixed in an amount of 10 to 20% by weight based on the total weight of the composite material, which is caused by the addition of small amounts of subsidiary materials such as fillers compared to conventional general synthetic wood (WPC). The best ratio for expressing the unique properties is shown.

UV stabilizer ( UV stabilizers )

The polymer material including the composite material according to the present invention is decomposed not only by heat but also by light to cause aging. Especially, ultraviolet rays, which correspond to 290 ~ 400nm among the sun rays, have strong energy, which acts as a major factor in plastic aging such as discoloration of plastic, surface cracking and deterioration of mechanical properties. The UV stabilizer plays a role of preventing the material from being decomposed from ultraviolet rays by selectively absorbing ultraviolet rays from sunlight and converting them into thermal energy or extinguishing free radicals generated by decomposition from ultraviolet rays.

Examples of substances that can prevent physical and chemical degradation caused by light include benzophenones (2-hydroxy benzophenone, etc.), benzotriazoles (2-hydroxy phenyl benzotriazole, etc.), and hindered amines (4-benzoyl). Oxy-2,2,6,6-tetramethylbiferidine, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-hydroxybenzoide, and the like; It can be used at a concentration of ~ 2% by weight. In the present invention, a UV stabilizer of a hindered amine light stabilizer (HALS) system is used in an amount of 0.1 to 0.2% by weight, and is not particularly limited.

Flame Retardant flame retardants )

Since synthetic wood may cause fire due to external factors, it is a compound that is added to composite materials to prevent ignition and delays the expansion of combustion, and has a high flame retardant effect generally represented by halogen, phosphorus, and nitrogen. A small amount may be added.

Binders ( coupling agents )

The binder is used to increase the binding force between the HDPE resin and the wood powder. In principle, the wood powder has a hydrophilic polarity and the resin component has a hydrophobic nonpolar property. To generate a new chemical bond at the interface of the present invention, MAPP (maleated polypropylene) contained 0.1 to 0.2% by weight based on the total weight, the binder is modulus of rupture (MOR) and modulus of elasticity , MOE), and also affects dimensional stability, impact strength and material dispersibility.

Antistatic agent ( antistatic agents )

As an additive used to increase the stability of the product due to static electricity and reduce the discomfort, various surfactants such as alkyl phosphate and quaternary ammonium salts are added in conventional amounts depending on the specific use of the synthetic wood.

Plasticizer ( plasticizers )

Plasticizers are materials that increase the flexibility, processability, or expandability of composites, most of which are produced by esterification of acids such as phthalic anhydride and adipic acid with alcohols such as octanol and nonanol. These plasticizers increase the fluidity of plastics by relieving intermolecular forces between molecules because they function to relieve secondary molecular intermolecular forces of the polymer to increase the mobility of the polymer. Therefore, the plasticizer should be compatible with the resin, but only a few plasticizers have one or two or more of the necessary properties, so they are often used in admixture. DOP, DINP, etc. are mainly used as plasticizers having excellent compatibility. There is no particular limitation on the kind.

Filler ( fillers )

Fillers are broadly classified into two types: extender fillers for cost reduction purposes and reinforcing fillers added to improve mechanical, thermal, electrical properties, or processability. Fillers are generally formulated in large quantities compared to other additives, and in many cases 40 to 50% is used. In the present invention, among various fillers, mineral fillers such as calcium carbonate, talc and mica can be used within 15% by weight, and the specific use of synthetic wood to improve long-term deformation due to impact strength, bending strength, heat deformation temperature and load. Optionally used according to

Antioxidants antioxidants )

It is used to control the deterioration or degradation of physical properties, cracks and discoloration due to the effects of oxygen, heat and light under practical environmental conditions. In the present invention, it is preferable to use an antioxidant of amines.

coloring agent( colorants )

Bamboo wood flour contains a highly soluble material, which may cause discoloration by dissolving the dissolved material to the surface, so that colorants such as pigments or dyes are added in an amount of 1 to 5% by weight in order to provide color stability. Is usually added with lubricant.

In addition, the present invention may be prepared by mixing the organic solvent, such as the pigment, dye, and the like, as the pigment and dye is not particularly limited as long as it is generally used in synthetic wood.

Other additives include lubricants, which add bamboo wood powder to improve dispersibility and improve the surface properties of synthetic wood, and heat stabilizers to help maintain the physical and chemical properties of processed or finished products. Additives for polymer materials such as heat stabilizers, organic inorganic antimicrobial agents, etc. are well known to those skilled in the art, and detailed descriptions thereof will be omitted to clarify the gist of the present invention.

Next, the process of manufacturing synthetic wood using the composite wood composite material will be described in detail.

(a) 45 to 65% by weight of cellulose fibers prepared by reacting bamboo wood flour with carbon disulfide (CS ₂ ), (b) 20 to 40% by weight of HDPE resin, and (c) 10 to 20% by weight of additives for addition. Each component of the composite wood composite material is mixed and then mixed using a cooling mixer. At this time, the rotation speed of the mixer is preferably 600 ~ 700rpm for about 10 to 12 minutes.

This composite material increases the efficiency of product production by increasing the cohesiveness and creaming flocculation, which are necessary to improve the processing speed and obtain the dimensional stability of molding during extrusion. .

The present invention after the step of extruding the composite material for synthetic wood into spherical or cylindrical pellets (pellets), and finished synthetic wood by any one of the molding method of extrusion molding, injection molding, compression molding by a mold It is manufactured by.

When the composite material mixed in the above-described method is used to produce a synthetic wood by extrusion molding using an extrudate manufactured in a pellet shape, it may be performed by a conventional balanced twin screw extrusion method. Specifically, the average extrusion speed is 0.6-0.7m and the extrusion discharge temperature is 150 ° C. or less at a ratio of 90 to 92 mm length of double balanced screws 25: 1. Extrusion is performed by passing vacuum after passing through a mold using cooling water.

In order to prevent rapid oxidation and discoloration due to high temperature, a double jacket is made in the mold to make the cooling water circulate.

Synthetic wood produced by the above method can exhibit a variety of patterns and colors and natural texture. In addition, the synthetic wood composition not only emits the natural bamboo fragrance in the finished product after molding, but also eliminates the feeling of rejection of the cold and slippery foreign material appearing in the plastic as the texture of the natural wood.

In addition, the present invention can be produced in a variety of synthetic wood finished products by any one of the molding method of injection molding, compression molding in addition to the manufacturing process by the extrusion molding.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

≪ Example 1 >

55% by weight of cellulose fibers extracted from bamboo wood flour, 30% by weight of HDPE resin, and additives containing 15% by weight of UV stabilizer, flame retardant, antistatic agent, antioxidant, antibacterial agent, plasticizer, filler To prepare a composite material by mixing for 10 to 12 minutes at 600 ~ 700rpm.

<Example 2>

The composite material composition prepared in Example 1 is extruded using a pellet extruder adjusted to 150 ° C. to form cylindrical pellets. The extrusion speed is set at 3 to 4 m / min to prevent material from carbonizing or discoloring. The purpose of the first extrusion molding has an advantage that the composite material composition subjected to the first heat is melted well even at a low temperature during the second molding, so that the molding speed can be easily increased and precise molding can be performed.

<Example 3>

The composite wood pellets prepared in Example 2 were extruded at a temperature of 150 ° C. using a main extruder (TWIN PARALLEL 92 mm Ratio 25: 1), and the composition melted using a mold of a desired shape. After passing through the sizing (sizing) through the vacuum and cooling process, the molding, withdrawal through the drawer, and cut to the appropriate size with a cutter to complete the synthetic wood.

<Example 4>

Comparison test of physical properties with existing wood products

Table 1 below is to help the understanding of the present invention CCA preserving wood, general synthetic wood (WPC), and the bamboo wood flour synthetic wood (BPC) prepared by Examples 1 to 3 by themselves compared to the results The present invention is not limited to the limited numerical range and is intended to demonstrate the fact that the present invention exhibits relatively superior physical and chemical properties as compared to conventional wood veneer or synthetic wood.

division CCA Preservative Plain Synthetic Wood (WPC) Bamboo Wood Powder Synthetic Wood (BPC) Density (g / cm 3) 0.8 1.2 1.45 Flexural strength (N / ㎡) - 23 52.20 Water absorption (%) 13 1.2 1.0 % Expansion - 1.2 0.6 Screw holding force (N) 480 580 630 Scratch Resistance (H) 2 3 5 or more

Example 5

Of synthetic wood according to the present invention Performance test

As shown in Table 2, the bamboo wood flour synthetic wood (BPC) prepared in Examples 1 to 3 are excellent results in water content, thickness expansion rate, flexural strength, flexural modulus, numerical change rate and the like compared to the standard value even in the performance test Indicated.

Inspection items Standard value Inspection Moisture content (%) <2 1.2 Hardness (HHR) > 58 60 Thickness expansion rate after absorption (%) <1 0.5 Flexural strength (MPa) > 20 29.7 Flexural Elastic Strength (MPa) > 1800 3490 Numerical rate of change after heating (%) <± 2.5 + 0.10 Weather resistance (300 hours) flexural strength > 16 18.4

Synthetic wood prepared as described above can be applied in various forms, such as interior and exterior materials for building, replacement of CCA preservatives, outdoor decks, pergola, bench interiors, and decorative structures.

1 is a manufacturing process chart of the synthetic wood according to the present invention.

Claims (10)

Cutting and grinding bamboo to prepare bamboo wood flour; A second step of extracting cellulose fibers by reacting the manufactured bamboo wood powder with carbon disulfide (CS ₂ ); A third step of neutralizing and desulfurizing the cellulose fibers by washing with sodium hydroxide aqueous solution 1 to 5 times, and then drying them to have a water content of 8% or less; 45 to 65% by weight of the cellulose fiber, 20 to 40% by weight of HDPE resin, and UV stabilizers, flame retardants, binders, antistatic agents, plasticizers, fillers, antioxidants, colorants, lubricants, heat stabilizers, antimicrobial additives containing at least one A fourth step of forming a composite material by mixing 10 to 20% by weight of the auxiliary material; Method for producing a composite material for synthetic wood containing bamboo wood flour, characterized in that it comprises a. The method of claim 1, And a fifth step of extruding the composite material formed in the fourth step into spherical or cylindrical pellets. (a) 45 to 65% by weight of cellulose fibers prepared by reacting bamboo wood flour with carbon disulfide (CS ₂ ), (b) 20 to 40% by weight of HDPE resin, and (c) Bamboo wood, characterized in that consisting of 10 to 20% by weight of additives containing at least one of ultraviolet stabilizer, flame retardant, binder, antistatic agent, plasticizer, filler, antioxidant, colorant, lubricant, thermal stabilizer, antibacterial agent Composite wood composite materials containing powder. The method of claim 3, The bamboo wood flour has a ratio of length to diameter of 5: 1 or less, and the cellulose fiber has a length of 4 mm or less composite wood composite material containing bamboo wood flour. The method of claim 3, The cellulose fiber is a composite material for synthetic wood containing bamboo wood flour, characterized in that it contains lignin and wax. The method of claim 3, The HDPE resin has a density of 0.940 ~ 0.980g / cm 3, containing bamboo wood flour, characterized in that to collect and wash the waste scraps of waste HDPE products and to use recycled resin made of pellets alone or mixed with new resin Composite materials for synthetic wood. delete The method of claim 3, The UV stabilizer is a HALS (hindered amine light stabilizer) system, the binder is MAPP (maleated polypropylene), synthetic wood containing bamboo wood flour, characterized in that it contains 0.1 to 0.2% by weight relative to the total weight of the composite material Composite materials. A synthetic wood produced by molding the composite material according to any one of claims 3 to 6 and 8 into a mold. 10. The method of claim 9, Molding by the mold is a synthetic wood produced by any one of the molding method of extrusion molding, injection molding, compression molding.

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