KR100932173B1 - Wood plastic composite compositions and profiles - Google Patents

Abstract

PURPOSE: A composition for wood-plastic composite materials and the wood-plastic composite materials using the same are provided to improve extrusion molding speed remarkably by maintaining the wood dust content high through dispersion and adhesion of wood dust and resin. CONSTITUTION: A composition for wood-plastic composite materials is manufactured by mixing raw materials including wood dust and polyolefin resin. The composition includes the wood dust of 35~80 weight%, the polyolefin resin of 8.5~55 weight%, alkaline earth metal oxide of 2~5.5 weight% gained by thermally decomposing alkaline earth metal soap at a temperature of 450°C, a compatibilizing agent of 0.3~0.5 weight%, a lubricant of 1~3 weight% and a coloring agent of 1.5~2.5 weight%. The oxide of the wood dust, the polyolefin resin and the alkaline earth metal includes the wood dust of 40~75 weight%, the polyolefin resin of 13.5~50 weight%, and the alkaline earth metal oxide of 2~5.5 weight%.

Description

Composition for wood-plastic composites and wood-plastic composites produced using the composition

The present invention relates to a composition for wood-plastic composites and to wood-plastic composites prepared using the composition, and more particularly to adding alkaline earth metal oxides of nanoparticles to the composition for wood-plastic composites including wood and plastics. Thus, the composition for wood-plastic composites and the composition prepared using the composition can be easily produced without deteriorating the properties of wood-plastic composites without thorough control of the water content in wood flour. A wood-plastic composite material.

Wood-plastic composites (WPC: wood-plastic composites) manufactured by adding wood powder to thermoplastic olefin resins have been actively developed since they are environmentally friendly as recyclable building materials. The wood-plastic composite should be manufactured by dispersing the hydrophilic wood flour or wood fiber and hydrophobic polyolefin resin effectively and evenly and tightly to obtain sufficient flexural strength and water resistance.

Patent technology related thereto is registered, and the use of a compatibilizer such as a maleic anhydride-containing polymer is common.

Korean Patent Laid-Open Publication No. 10-2007-0100266 (Dow Global Technologies Inc.) discloses a technique for producing wood-plastic composite having excellent strength by treating wood fibers with an unsaturated silane-containing polymer.

In the technique of this publication, the technique of bonding unsaturated silane to the hydrophilic functional group (-OH) of wood fibers to form hydrophobic polymer chains on the surface of wood flour to promote the bond with olefin resin, but the water content of wood flour is high. The effect is unknown.

According to U.S. Patent No. 6,682,789 (Techwood International), a high content of wood powder decreases the efficacy of the compatibilizer, and thus, a technology for producing a superior wood-plastic composite material by thoroughly managing it at a level of 0.1 to 0.35% is disclosed. have.

In addition, according to US Patent No. 6,929,841 (Techwood International), wood having excellent performance by blending 50 to 70% of the long-fiber wood flour (length / width = 6 to 30) with a moisture content of 0.5% or less based on the total weight. A technique for producing plastic composites is disclosed.

According to the techniques disclosed in these documents and the experiments of the present invention, the dispersion and bonding of wood flour and polyolefin resin is a key factor in the performance of wood-plastic composites. For this purpose, the type of olefin resin, the type and content of wood flour, Types and compounding costs are the main management targets. In particular, when the water content of wood flour is high, it is difficult to disperse and adhere the resin and wood powder, but if enough compatibilizer is used, a certain level of wood-plastic composite can be produced.

However, if the most widely used polyolefin-based compatibilizer containing maleic anhydride is used sufficiently, the cost of manufacturing thereof is very high.

In addition, when manufacturing the wood-plastic composite material, increasing the content of wood powder can increase the extrusion molding speed, so that the productivity of the molded product can be improved. However, when the compatibilizer is used excessively, the quality of strength, absorption rate, appearance, etc. are reduced. Will be.

The present inventors have endeavored to solve the problems caused by the moisture content of the wood powder, which led to the present invention.

In other words, from the fact that the moisture of wood flour interferes with the role of promoting the dispersion and adhesion of the compatibilizer, the material that can react with the moisture of the wood powder is first examined and tested in various ways. As a result, alkaline earth metals such as calcium and magnesium Invented a composition that allows alkaline earth metal oxides of nanoparticles obtained by pyrolysing soaps (calcium stearate or magnesium stearate) at 450 degrees Celsius to produce wood-plastic composites without precisely controlling the amount of water in wood Was done.

That is, when blending about 8% of the wood flour, which is the equilibrium moisture content of wood flour, with polypropylene or polyethylene resin, and extruded by melting and kneading the composition kneaded and kneaded together with a small amount of the compatibilizer and other additives It is possible to continuously produce wood-plastic composites with high strength and low absorption.

Document 1: Korean Unexamined Patent Publication No. 10-2007-0100266 (Dow Global Technologies Inc.)

Document 2: US Patent No. 6,682,789 (Techwood International)

Document 3: US Patent 6,929,841 (Techwood International)

Accordingly, an object of the present invention is to solve the conventional problems as described above, using wood flour and polyolefin resin as a main component of the wood-plastic composite material to easily produce a wood-plastic composite having a similar appearance and texture to wood. It is possible to provide a composition for wood-plastic composite and a wood-plastic composite prepared using the composition.

In addition, another object of the present invention is to prepare a wood-plastic composite composition for producing a wood-plastic composite having excellent productivity and performance without thorough management of the moisture content contained in the wood flour in the manufacture of wood-plastic composite and its To provide a wood-plastic composite produced using the composition.

Wood-plastic composite composition according to the present invention for achieving the above object is a wood-plastic composite composition prepared by mixing a raw material containing wood powder and polyolefin resin, the composite composition is 35 to 80% by weight of wood powder (Drying standard with 0% water content), 8.5 to 55% by weight of polyolefin resin, 2 to 5.5% by weight of alkaline earth metal oxide of nanoparticles obtained by pyrolyzing alkaline earth metal soap at 450 ° C, 0.3 to 0.5% by weight of compatibilizer, lubricant It is characterized by the fact that it is 1-3 weight% and the coloring agent 1.5-2.5 weight%.

In addition, in the composition for wood-plastic composite according to the present invention, the wood powder, polyolefin resin and alkaline earth metal oxide are 40 to 75% by weight of wood powder (drying basis of 0% water content), 13.5 to 50% by weight of polyolefin resin, alkali It is characterized by 2 to 5.5 weight% of earth metal oxides.

In addition, in the composition for wood-plastic composite according to the present invention, the wood powder, polyolefin resin and alkaline earth metal oxide are 50 to 65% by weight of wood powder (dry basis with 0% water content), 24 to 40% by weight of polyolefin resin, alkali It is characterized by 3 to 5 weight% of earth metal oxides.

In addition, in the composition for wood-plastic composite according to the present invention, the polyolefin resin is characterized in that the polypropylene resin or polyethylene resin.

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In addition, in the composition for wood-plastic composite according to the present invention, the composition is characterized in that any one or two or more of a light stabilizer, antioxidant, ultraviolet absorber is added.

In addition, the wood-plastic composite material according to the present invention for achieving the above object is a wood-plastic composite prepared by mixing wood powder containing water with a raw material comprising a polyolefin resin, the wood-plastic composite is the wood- After melt-kneading the composition of any one of the compositions for plastic composites to produce a pellet, it is characterized in that the pellet produced by extrusion molding.

In addition, in the wood-plastic composite according to the present invention, the melt kneading is characterized by using a twin screw extruder-kneader.

As described above, the composition for wood-plastic composite according to the present invention and the wood-plastic composite prepared using the composition have a small amount of commercially available nanoparticle alkaline earth metal oxide when producing wood-plastic composite from wood flour and polyolefin resin. By adding it together with fire, wood flour and resin are evenly dispersed and adhered evenly even if the wood flour of 8% of equilibrium moisture content is used without adjusting the moisture content of wood flour to 0.5% or less as before. It has the effect of producing composites.

In addition, the wood-plastic composite according to the present invention and the wood-plastic composite prepared using the composition control the dispersion and adhesion of wood flour and resin, thereby maintaining a high wood flour content to significantly improve the extrusion molding speed. There are also effects that can be made.

In addition, the composition for wood-plastic composites according to the present invention and the wood-plastic composite prepared using the composition can reduce the amount of expensive compatibilizers that promote the dispersion and adhesion of wood flour and polyolefin, and the amount of compatibilizers used. In addition, the quality of wood-plastic composites can be improved.

Wood-plastic composite material should be closely contacted with the polyolefin resin, the main component of the wood powder evenly and uniformly dispersed to be able to fully exhibit the mechanical strength, it is possible to produce a practical molded article excellent in water resistance and weather resistance. However, since the properties of polyolefin and wood flour are hydrophobic and hydrophilic, respectively, they do not mix well with each other. Therefore, a practical wood-plastic composite can be produced by increasing dispersibility and adhesion using a compatibilizer such as maleic anhydride-containing polyolefin.

However, if the moisture content of wood flour is high, the dispersibility and adhesion exhibited by the compatibilizer are inferior, and an excessive compatibilizer must be used.

Therefore, the present inventors are expected to increase the effectiveness of the compatibilizer by reacting the alkaline earth metal oxide with the moisture of the wood powder, and tested the various compositions using calcium oxide and magnesium oxide powder, but the amount of the compatibilizer was not significantly reduced.

Since the reactivity of these metal oxides will be proportional to the surface area, several attempts have been made to obtain fine particles of metal oxides, and it has been found that the particles of oxides obtained by pyrolysis of alkaline earth metal stearate at 450 ° C. are obtained in nano size.

Therefore, the present inventors can increase the content of wood powder while significantly reducing the amount of compatibilizer used in the composition tested using the nano-sized oxide particles thus obtained, that is, the nano-oxide of alkaline earth metal, It has been found that wood-plastic composites with sufficient strength and low water absorption can be produced.

Hereinafter, the preparation of the composition for wood-plastic composite and the method for producing the wood-plastic composite according to the present invention will be described in detail with reference to examples.

The following examples are only intended to specifically describe the contents of the present invention, and are not intended to limit the scope of the present invention, the above and other objects and novel features of the present invention, such as examples and comparative examples of the present specification. The description will be made clearer.

In the present invention, polyolefin refers to polypropylene (PP) and polyethylene (ethylene polymers such as HDPE, LDPE, LLDPE), copolymers thereof, and mixtures of these polymers.

Wood powder (WF) used in the Examples and Comparative Examples of the present invention was used as lignocell C120 (100-mesh, moisture content 8.0%) of JRS, Germany, polypropylene (PP) and polyethylene (PE), respectively, Honam Petrochemical SY130 and LG Chem's BF511 were used, and nano-oxides of alkaline earth metals were prepared by pyrolyzing magnesium stearate at 450 ° C. to prepare nanoparticle magnesium oxide (MO).

The compatibilizer (MAP) used Honam Petrochemical's polyolefin BP-400 or EM-510H containing maleic anhydride, the lubricant (LUB) used calcium stearate, and the colorant (PIG) used iron oxide pigments of beneficial companies. .

As an additive (ADD), a light stabilizer (Ciba Geigy, Chimassorb 944), an antioxidant (Ciba Geigy, Irganox 1010), and an ultraviolet absorber (American Cynamid, Cyasorb UV531) were used in combination at a weight ratio of 2: 2: 1.

The raw materials of the composition for wood-plastic composites according to the present invention as listed above do not limit the practice of the present invention, and raw materials generally used in addition to these may be used.

The wood flour, resin and other raw materials used in the examples and comparative examples of the present invention were melt extruded while feeding to a two-axis screw extrusion-kneader having a diameter of 78-mm at a predetermined speed using an automatic continuous weighing device, respectively. The extruded strand was cut to prepare pellets.

These pellets were attached to a 75-mm single screw extruder with a die having a cross section as shown in FIG. 1 to produce a deck material profile (unit weight about 2.5 kg per meter).

The extrusion speed was determined by observing the appearance of the profile produced by gradually increasing the screw rotation speed, and determined as the maximum speed within the range where the surface was smooth, cracked, surfaced, bent, and not bent. Deck profile was cut and immersion absorption was measured by flexural strength and hot water immersion (70 ° C., 72 hours) test method.

EXAMPLES 1-9

The wood-plastic composite composition was mixed while increasing the wood flour content from 35% to 80% by weight of the total weight of the composition (0% water content on a dry basis) using a 78-mm 2-axis screw extrusion-kneader. Pellets were prepared by melt kneading at less than 180 ° C.

Since the actual amount of wood powder is 8.0% of moisture content, 108% of the dry wood powder content is weighed, and the composition ratio of these wood-plastic composite compositions is shown in Table 1.

These composition pellets were determined by maximally increasing the speed of extrusion of the 75-mm single screw extruder while determining the maximum speed of the extrusion in the range of the appearance of the wood-plastic composite, as shown in FIG. The deck material of mm was extruded at 170 degrees C or less.

Table 1 is a composition table for each embodiment of the composition for wood-plastic (polypropylene resin) composite according to the present invention.

[Table 1] (Unit: weight%)

 PP WF  MO  MAP  LUB  PIG  ADD  Sum Dry ^* Function (8%) ^** Example 1 55.0 35.0 37.8 2.2 0.5 2.0 2.3 3.0 100.0 Example 2 50.0 40.0 43.2 2.2 0.5 2.0 2.3 3.0 100.0 Example 3 39.5 50.0 54.0 3.2 0.5 2.0 2.0 2.8 100.0 Example 4 34.2 55.0 59.4 4.0 0.5 2.0 2.0 2.3 100.0 Example 5 29.2 60.0 64.8 4.3 0.4 2.0 2.0 2.1 100.0 Example 6 24.2 65.0 70.2 4.4 0.4 2.0 2.0 2.0 100.0 Example 7 19.0 70.0 75.6 4.6 0.4 2.0 2.0 2.0 100.0 Example 8 13.6 75.0 81.0 5.0 0.4 2.0 2.0 2.0 100.0 Example 9 8.9 80.0 86.4 5.2 0.3 2.0 1.8 1.8 100.0

PP) Polypropylene resin, WF: Wood powder (dry ^* : Dry wood powder, water (8%) ^** : Wood powder with water content of 8%), MO: Magnesium oxide, MAP: Compatibilizer, LUB: Lubricant, PIG: Colorant , ADD: additive (light stabilizer, antioxidant, ultraviolet absorber)

Composites prepared from the composition for wood-plastic composites according to the present invention using polypropylene resin were measured for the bending strength of the prepared profile, and immersed in hot water at 70 ° C. for 72 hours to measure the water absorption.

Table 2 is a characteristic table for each embodiment of the composition for wood-plastic (polypropylene resin) composite according to the present invention.

TABLE 2

PP (wt%) WF (dry ^* ) (% by weight) Extrusion speed (m / h) Flexural Strength (MPa) Immersion Absorption Rate (%) Example 1 55.0 35.0 18.8 20.3 1.9 Example 2 50.0 40.0 20.7 21.4 2.1 Example 3 39.5 50.0 33.8 22.3 2.4 Example 4 34.2 55.0 47.5 23.5 2.3 Example 5 29.2 60.0 52.6 24.0 2.5 Example 6 24.2 65.0 61.3 25.2 2.7 Example 7 19.0 70.0 65.7 22.6 2.8 Example 8 13.6 75.0 69.6 18.5 3.1 Example 9 8.9 80.0 72.0 16.0 5.3

When the content of wood flour was less than 35% by weight, the same texture as wood could not be obtained. Therefore, the experiment was performed when the content of wood flour having the same texture as wood was more than 35% by weight.

As shown in Table 2, the content of wood flour increased from 40% by weight to 50% by weight to 80% by weight, and the extrusion speed was increased to about 50-350% compared to 40% by weight. It can be seen that the larger. In other words, in terms of production speed, it is advantageous to increase the content of wood flour, but when the content of wood powder is 70% by weight or more, the bending strength decreases and the immersion absorption rate is greatly increased.

Therefore, the practical wood flour content is preferably in the range of 40 to 75% by weight, more preferably in the range of 50 to 65% by weight.

That is, the optimum wood flour content of the wood-polypropylene composite prepared using the nano-oxide of alkaline earth metal is 50 to 65% by weight, and the extrusion speed is 33.6 to 63.3 m / hour, and the bending strength is 22.3 to 25.2 MPa, Immersion absorption rate has a characteristic of 2.1-2.7%.

[Comparative Examples 1 and 2]

Comparative Examples 1 to 2 are equilibrium moisture contents 8 in order to examine the effect of wood flour on the case of using only the polypropylene containing maleic anhydride, which is a conventional compatibilizer, without using the nano-oxide of alkaline earth metal used in the present invention. The wood-plastic composite composition having a wood flour content of 40% by weight using% wood flour and dry dry wood flour (0.5%) was prepared as shown in Table 3 and extruded in the same manner as in Example.

Table 3 is a composition table for each comparative example of the composition for wood-plastic composite according to the comparative example.

[Table 3] (Unit: weight%)

 PP WF  MAP  LUB  PIG  ADD  Sum Dry ^* Function (function rate) Comparative Example 1 50.0 40.0 43.2 (8%) 3.0 2.0 2.0 3.0 100.0 Comparative Example 2 50.0 40.0 40.2 (0.5%) 0.5 4.5 2.0 3.0 100.0

Table 4 is a characteristic table for each comparative example of the composition for wood-plastic composite according to the comparative example.

TABLE 4

PP (%) WF (dry ^* ) (%) Extrusion speed (m / h) Flexural Strength (MPa) Immersion Absorption Rate (%) Comparative Example 1 50.0 40.0 17.8 18.3 2.1 Comparative Example 2 50.0 40.0 19.1 17.8 2.0

As shown in Table 4, when manufacturing the composite from dry wood powder, an extrusion rate of 19.1 m / hour is obtained even with 0.5% of a compatibilizer. For wood flour containing 8% of equilibrium moisture, the compatibilizer is about 3%. It can be seen that it can be extruded at a similar speed by using. When only these compatibilizers were used, the immersion absorption rate was almost similar to that of the example, but the flexural strength was slightly decreased. This can be seen that the metal oxide in the embodiment of the present invention is a great help in the dispersion and adhesion of wood flour and olefin resin.

[Examples 10 to 13]

Examples 10 to 13 are polyethylene (PE) resins used in place of the polypropylene resins used in Examples 1 to 9, and a composition for plastic composites was prepared as shown in Table 5 and extruded in the same manner as in Examples 1 to 9. Prepared.

Table 5 is a composition table for each embodiment of the composition for wood-plastic (polyethylene resin) composite according to the present invention.

[Table 5] (Unit: weight%)

 PE WF  MO  MAP  LUB  PIG  ADD  Sum Dry ^* Function (8%) ^** Example 10 34.5 55.0 59.4 4.0 0.5 2.0 2.0 2.0 100.0 Example 11 30.0 59.2 63.9 4.3 0.5 2.0 2.0 2.0 100.0 Example 12 24.0 65.0 70.2 4.5 0.5 2.0 2.0 2.0 100.0 Example 13 19.0 70.0 75.6 4.5 0.5 2.0 2.0 2.0 100.0

Note) PE: polyethylene resin

Table 6 is a characteristic table for each embodiment of the composition for wood-plastic (polyethylene resin) composite according to the present invention.

TABLE 6

PE (% by weight) WF (dry ^* ) (% by weight) Extrusion speed (m / h) Flexural Strength (MPa) Immersion Absorption Rate (%) Example 10 34.5 55.0 46.3 22.7 2.1 Example 11 30.0 59.2 49.4 23.8 2.4 Example 12 24.0 65.0 58.3 25.0 2.5 Example 13 19.0 70.0 63.7 23.3 2.7

In Examples 10 to 13, as in Examples 1 to 9 (when using a polypropylene resin), as the content of wood powder increased, the extrusion speed increased, and the flexural strength increased and decreased until 65% by weight of wood powder, and the immersion absorption rate continued to increase. The tendency was the same, and the optimum wood compounding ratio was 55 to 65% by weight.

Figure 2 is a photograph of a wood-plastic composite prepared using the composition according to the present invention, the texture is similar to wood, showing a color-like appearance similar to wood.

According to the present invention, the wood-plastic composite material is made of inexpensive raw materials without having to thoroughly manage the moisture of wood powder. It will help to increase the dissemination of wood-plastic composites, and will contribute to the development of green industry by promoting the recycling of resources.

1 is a view showing a profile of a wood-plastic composite according to an embodiment and comparative example of the present invention

2 is a photograph of a wood-plastic composite prepared using the composition according to the invention.

Claims (7)

In the composition for wood-plastic composites prepared by blending raw materials containing wood flour and polyolefin resin, The composition for the composite material is 2 to 5.5 weight of alkaline earth metal oxide of nanoparticles obtained by pyrolysing 35 to 80% by weight of wood powder (drying standard with 0% water content), 8.5 to 55% by weight of polyolefin resin and alkaline earth metal soap at 450 ° C. %, 0.3 to 0.5% by weight compatibilizer, 1-3% by weight of lubricant and 1.5 to 2.5% by weight colorant composition for wood-plastic composites. The method of claim 1, The wood flour, the polyolefin resin and the oxide of the alkaline earth metal is wood wood, characterized in that 40 to 75% by weight (dry basis of 0% water content), 13.5 to 50% by weight of polyolefin resin, 2 to 5.5% by weight of alkaline earth metal oxide Composition for plastic composites. The method of claim 1, The wood flour, polyolefin resin and alkaline earth metal oxide are 50 to 65% by weight of wood powder (drying standard with 0% water content), 24 to 40% by weight of polyolefin resin and 3 to 5% by weight of alkaline earth metal oxide. Composition for plastic composites. The method of claim 1, The polyolefin resin is a composition for wood-plastic composites, characterized in that the polypropylene resin or polyethylene resin or a mixture thereof. delete The method according to any one of claims 1 to 4, The composition is a composition for wood-plastic composites, characterized in that any one or two or more of a light stabilizer, antioxidant, ultraviolet absorber is added. In the wood-plastic composite prepared by blending raw materials comprising wood flour and polyolefin resin, The wood-plastic composite is manufactured by melt-kneading the composition of any one of claims 1 to 4 to produce pellets, and then extruding the pellets to produce wood-plastic composites.

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