KR20120127810A - Coextruded wood/plastic composites with excellent weathering resistance - Google Patents

Abstract

PURPOSE: A coextruded synthetic wood with improved weather resistance and lowered discoloration is provided to give ultraviolet ray stability and to enhance weather resistance. CONSTITUTION: A coextruded synthetic wood with improved weather resistance is polymer/wood dust synthetic wood. The synthetic wood contains 100-15 parts by weight of wood powder, 1-5 parts by weight of UV stabilizer and/or UV blocking/absorbing pigment and 0.2-3 parts by weight of additive based on 100 parts by weight of polymer. The polymer is selected from PP, PE, PVC, PS, PMMA, PET and a polymer thereof. The additive is one or more selected from anti-oxidant, coupling agent and lubricant. The anti-oxidant, coupling agent and lubricant are respectively used for 0.2-1 parts by weight, 1-3 parts by weight and 1-3 parts by weight based on 100 parts by weight of the polymer.

Description

Coextruded wood / plastic composites with excellent weathering resistance}

The present invention relates to a polymer / wood powder composite wood, and more specifically, to a polymer / wood powder composite wood produced by co-extrusion, the part located on the surface as a skin layer of the synthetic wood has excellent UV (UV) stability. The present invention relates to a coextruded synthetic wood having improved weather resistance.

WPC is a composite material made by mixing a suitable ratio of thermoplastic resin such as PP, HDPE, LDPE, PVC and natural fiber such as wood powder, and is widely used in various industrial fields such as building materials. WPC has been researched and developed to recycle environmentally friendly amounts of sawdust generated from the processing of waste wood and solid wood used as building materials, and the processing method of melt blending wood powder into thermoplastic resin is studied the most. . WPC building materials manufactured by extrusion or injection processing of such eco-friendly wood powder / polymer composite materials are widely used as a substitute material to compensate for various disadvantages of building materials made of a single material made of wood or plastic. In addition, PP, a thermoplastic resin, is widely used around us as a general purpose plastic, and has a soft texture due to its excellent mechanical, physical and chemical properties, high durability, chemical resistance, and compatibility with various additives. You can make a wide range of products, from textiles to building materials.

In addition, WPC is mainly used as an external building material as a composite of wood flour and thermoplastic resin. Therefore, the physical properties of the product may be reduced by external moisture, ambient temperature, ultraviolet light, bacteria, insects, and the like. Among them, discoloration affected by ultraviolet rays is caused by discoloration of pigment inside polymer matrix or protrusion of wood powder on the surface of WPC when ultraviolet ray is irradiated, that is, long time exposure to direct sunlight. It is important to prevent or minimize discoloration of WPC as a standard of WPC's primary weather resistance because materials discolor not only look aesthetically, but also adversely affect properties and lead to performance degradation.

In accordance with the necessity as described above, Utility Model Registration No. 20-0418267 discloses synthetic wood for decks and balustrade pillars, forming synthetic wood into a multilayer of skin layer and core layer, wherein the skin layer is 25 ~ 30 wt% of synthetic resin, wood powder 57 It was suggested that the core layer was formed of a mixture of ~ 65wt% and 10-15wt% functional additive, and the core layer was made of a mixture of 25 ~ 35wt% recycled resin and 65 ~ 75wt% wood powder.

However, the registration utility model does not reveal the reason for limiting the content of each component, so the implementation is suspected.

In addition, Patent No. 10-0530419 discloses a composite wood product using a multi-coextrusion and a method of manufacturing the same, the patent uses a three or more multi-coextrusion method of three or more layers of synthetic wood products, thermoplastic resin 70 ~ 80wt%, impact resistant reinforcement 5 ~ 10wt%, filler 5 ~ 15wt%, composite stabilizer 3 ~ 7.5wt%, pigment 2 ~ 8wt%, and synthetic fiber containing 3 ~ 20wt% phenolic compound removed Wood products were presented. However, the patent is complicated, such as the need to remove the phenolic compound from the vegetable fiber material, the patent also has a problem that does not reveal the reason for limiting the content of each component.

The present invention solves the problems of the prior art as described above, by using a co-extrusion process method, the weather resistance reinforced WPC is placed on the surface of the WPC to synthesize a composite of PP / wood powder with improved weather resistance showing excellent UV stability The purpose is to provide wood.

The present invention, in order to achieve the object of the present invention as described above, at least one polymer selected from PP, PE, PVC, PS, PMMA, PET and a polymer copolymer comprising these polymers, wood flour, UV stabilizer and / or It provides a synthetic wood comprising a pigment having an ultraviolet stabilizing effect, and an additive.

In the above, the additive is preferably used one or more selected from antioxidants, coupling agents, lubricants.

In addition, the content of each component in the above is 100 to 150 parts by weight based on 100 parts by weight of polymer, 1 to 5 parts by weight of UV stabilizer and / or UV stabilized functional pigments, and the additive is preferably used 0.2 to 3 parts by weight, It is more preferable that the antioxidant uses 0.2-1 weight part, the coupling agent 1-3 parts by weight, and the lubricant 1-3 parts by weight in the additive.

In the content of each component, when the wood powder is used in less than 100 parts by weight of the wood content is low, it is difficult to express the function as a synthetic wood, when using more than 150 parts by weight has a difficulty in the synthetic wood manufacturing process is in the above range . In addition, the UV stabilizer is added to have a weather resistance to ultraviolet light because the skin layer of the polymer / wood synthetic wood surface part is exposed to ultraviolet light, the amount of UV stabilizer used is about based on 100 parts by weight of the polymer as described above 1 to 5 parts by weight, but less than 1 part by weight it is difficult to expect a sufficient UV stabilization effect, when exceeding 5 parts by weight is no longer the UV stabilization effect due to excessive use and can be a deterioration factor of synthetic wood It is also used in the above range because it is also a cost increase factor.

And the pigment used in the present invention can be used for all the UV stabilizing effect through the UV blocking and absorbing action, the amount is preferably used 1 to 5 parts by weight based on 100 parts by weight of the polymer is less than 1 part by weight This is because it is difficult to expect sufficient color expression, UV protection and absorption effect, and at least 5 parts by weight may not only be a performance deterioration factor of synthetic wood but also a cost increase factor.

In addition, the antioxidant is used as 0.2 ~ 1 parts by weight as described above, but less than 0.2 parts by weight is difficult to expect a sufficient antioxidant effect, when exceeding 1 part by weight is no longer the antioxidant effect due to excessive use and deterioration factor of synthetic wood In addition to being able to be a cost increase factor, the above range is used, and the coupling agent is used for the purpose of improving the interfacial adhesion between wood powder and polymer, and in this case, it is difficult to expect sufficient interfacial adhesion improvement at 1 part by weight or less. , If it exceeds 3 parts by weight can not only be a performance deterioration factor of synthetic wood but also a cost increase factor, it is used in the above range, the lubricant is used for the purpose of smoothing the synthetic wood fabrication process, less than 1 part by weight It is difficult to expect lubrication performance, and the performance deterioration of synthetic wood is required at more than 3 parts by weight. Not only it can be a cost factor because the lift is used in the above-described range.

In the present invention, the co-extrusion method is used to produce the synthetic wood as described above, the surface layer of the polymer / wood composite wood by such a method has an excellent UV stability function, as a result of excellent UV stability enhanced weather resistance It is possible to provide synthetic wood.

Co-extruded PP / wood composite wood according to the present invention can be mainly used as interior and exterior building materials and has a UV stabilizing function on the surface, it is significantly low discoloration and environmentally friendly. The PP / wood flour composite contains large amounts of wood flour, so it is environmentally friendly because it can use scrap wood and other uneconomical wood, which are generated when processing waste wood or natural wood. As the importance of the environment has risen internationally, the emergence of sick house syndrome and environmental hormones has greatly increased the consumers' interest in eco-friendly products, which is also increasing the demand for environmentally friendly WPCs with wood powder. In this way, not only the costs incurred at the time of disposal, but also environmentally friendly in that the waste wood can be used. In addition, production of weathering-enhanced PP / wood powder composites using co-extrusion process technology can reduce production costs by reducing the use of expensive pigments and UV stabilizers. It can be used as a product. Therefore, the weathering-enhanced coextruded PP / wood composite wood according to the present invention has the effect of not only satisfying consumer's preference but also providing a product having the advantages of natural wood and plastic.

1 is a graph of the result of measuring the degree of discoloration before and after irradiating ultraviolet rays to synthetic wood for a long time (300 hours) with a color difference meter.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. The following examples are intended to assist those of ordinary skill in the art to which this invention pertains, but are not intended to limit the invention thereto.

The present invention is 100 parts by weight of PP resin to achieve the object of the present invention as described above; 100-150 parts by weight of wood flour; 1 to 5 parts by weight of UV stabilizers and / or UV stable functional pigments; Provided is the use of a PP / wood flour composite consisting of 0.2 to 7 parts by weight of other additives, such as antioxidants, coupling agents, lubricants, on the surface of the WPC during coextrusion.

Example 1

Polypropylene resin used in this embodiment is 100 parts by weight of PP (J-160, MFI = 16 g / 10 min, Mw = 219,300 g / mol, density = 0.90 g / cm ³ ) of Honam Petrochemical Co., Ltd. 150 parts by weight of wood powder (K0-008 of Dongwon Chemical) was used after removing water from an oven at 100 ° C., and UV stabilizer was used in 3 parts by weight of Tinuvin XT855 of BASF. As other additives, 0.5 parts by weight of antioxidant, 2 parts by weight of coupling agent, and 2 parts by weight of lubricant were used.

PP / wood powder specimens were introduced into the internal mixer in an amount of PP, wood flour, UV stabilizer and other additives, and then stabilized under melt blending conditions of 160-200 ° C and 40-70 rpm. After sufficient mixing, the molten mixture was taken out of the internal mixer, placed between hot presses, and then produced in the form of panels by compression molding. Each material was first dry blended and then placed in an internal mixer. Specimens for colorimeter experiments were made by cutting panels. A UV-chamber equipped with a high pressure mercury ultraviolet lamp was used to irradiate each synthetic wood (WPC-UV stabilizer) specimen with ultraviolet rays to conduct a weathering test. The intensity of ultraviolet rays irradiated onto the surface of the synthetic wood was 1.76 ㎽ / ㎠ and the color change of the specimens was investigated by the color difference meter according to the UV irradiation time.

[Example 2]

Polypropylene resin used in this embodiment is 100 parts by weight of PP (J-160, MFI = 16 g / 10 min, Mw = 219,300 g / mol, density = 0.90 g / cm ³ ) of Honam Petrochemical Co., Ltd. 150 parts by weight of wood powder (K0-008 of Dongwon Chemical) was used after removing water from an oven at 100 ° C, and 3 weights of red and yellow pigments (Koch 130, Yellow 960) were used. Parts, 0.5 parts by weight, and no UV stabilizer was used. As other additives, 0.5 parts by weight of antioxidant, 2 parts by weight of coupling agent, and 2 parts by weight of lubricant were used.

The PP / wood flour composite wood specimen is mixed with sufficient amounts of PP, wood flour, pigments and other additives into the internal mixer until the torque is stabilized under melt blending conditions of 160 to 200 ° C and 40 to 70 rpm. The molten mixture was taken out from the internal mixer, placed between hot presses, and then produced in the form of panel wood by compression molding. Each material was first dry blended and then placed in an internal mixer. Specimens for colorimeter experiments were made by cutting panels. The accelerated weathering test was carried out by irradiating ultraviolet rays to each composite wood (WPC-Pigment) specimen using a UV chamber equipped with a high-pressure mercury ultraviolet lamp. The intensity of ultraviolet rays irradiated onto the surface of the synthetic wood was 1.76 ㎽ / ㎠ and the color change of the specimens was investigated by the color difference meter according to the UV irradiation time.

Comparative Example 1

PP / wood flour WPC was prepared without the addition of UV stabilizers and pigments as compared to Examples 1 and 2. As in Examples 1 and 2, 100 parts by weight of PP (J-160, MFI = 16 g / 10 min, Mw = 219,300 g / mol, density = 0.90 g / cm 3) of Honam Petrochemical Co., Ltd. It was used, 150 parts by weight of wood flour (K0-008 of Dongwon Chemical) of 70 ~ 150㎛ size was used after removing water in an oven at 100 ℃. UV stabilizers and pigments were not used. Other additives included 0.5 parts by weight of antioxidant, 2 parts by weight of coupling agent, and 2 parts by weight of lubricant.

 PP / Wood flour composite wood specimen is mixed with PP, wood flour and other additives into the internal mixer until the torque is stabilized under melt blending conditions of 160 ~ 200 ℃ and 40 ~ 70rpm. It was taken out from the null mixer, placed between hot presses, and then produced in the form of panels by compression molding. Each material was first dry blended and then placed in an internal mixer. Specimens for colorimeter experiments were made by cutting panels. The accelerated weathering test was carried out by irradiating ultraviolet rays to each composite wood (WPC-None) specimen using a UV chamber equipped with a high-pressure mercury ultraviolet lamp. The intensity of ultraviolet rays irradiated onto the surface of the synthetic wood was 1.76 ㎽ / ㎠ and the color change of the specimens was investigated by the color difference meter according to the UV irradiation time.

PP / wood flour synthetic wood (WPC-UV Stabilizer of FIG. 1) to which the UV stabilizer of Example 1 was added, PP / wood flour synthetic wood (WPC-Pigment of FIG. 1) to which the pigment of Example 2 was added, and Comparative Example 1 After long time (300 hours) UV exposure of PP / wood composite wood (WPC-None in FIG. 1) without UV stabilizer and pigment, the degree of discoloration was measured using a color-difference meter. The results are shown. The discoloration of the PP / wood synthetic wood (WPC-UV Stabilizer) added with the UV stabilizer of Example 1 was much lower than the discoloration degree of the PP / wood composite wood (WPC-None) without the UV stabilizer of the comparative example 1 It can be seen that the ultraviolet stability is excellent. In addition, the discoloration of the PP / wood synthetic wood (WPC-Pigment) added with the pigment of Example 2 is much lower than the discoloration degree of the PP / wood composite wood (WPC-None) without the pigment of Comparative Example 1 It can be seen that this is excellent. Variables affecting the degree of discoloration by UV exposure of polypropylene-based synthetic wood are PP type, wood powder content and type, UV stabilizer content and type, pigment content and type, melt processing temperature, and retention time in the extruder. Etc., but the addition of an appropriate amount of UV stabilizer or the addition of the pigment was found to have a great effect.

Claims (3)

As a polymer / wood flour synthetic wood produced by the co-extrusion method, 100 to 15 parts by weight of wood powder, based on 100 parts by weight of a polymer selected from PP, PE, PVC, PS, PMMA, PET and a polymer containing these polymers; 1 to 5 parts by weight of UV stabilizers and / or UV stable functional pigments;
And 0.2 to 3 parts by weight of an additive. The synthetic wood according to claim 1, wherein the additive is at least one selected from an antioxidant, a coupling agent, and a lubricant. 3. The synthetic wood according to claim 2, wherein the antioxidant is used in an amount of 0.2-1 part by weight, a coupling agent in an amount of 1-3 parts by weight and a lubricant in an amount of 1-3 parts by weight, based on 100 parts by weight of the polymer.

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