KR101239627B1 - Heavy metal free-PVC/wood flour/nanosilica nanocomposites with good dimensional stability - Google Patents

Abstract

Nontoxic-PVC / wood powder / with excellent dimensional stability using nanosilica, which can be used as interior and exterior materials in an eco-friendly and economical way by using nanosilica as nanofiller and non-toxic stabilizer without heavy metal to improve dimensional stability. A nanosilica nanocomposite and a method of manufacturing the same are disclosed. Nanocomposite according to the present invention comprises 1 to 80 parts by weight of wood powder, and 10 to 10 parts by weight of nanosilica as a nano filler, PVC compound contains 0.5 to 10 parts by weight of a non-toxic stabilizer based on 100 parts by weight of PVC compound. It may be characterized in that the filler, impact reinforcing material and pigment may be included, the wood powder is used in the 70 ~ 150㎛ size, the nano-silica uses a particle size of 100nm or less. In addition, in order to provide the nanocomposite as described above, 1 to 80 parts by weight of wood powder and 10 parts by weight or less of nanosilica having a size of 70 to 150 μm and 100 parts by weight of PVC compound are added to an internal mixer, and then 160 to 200. Provided is a method for producing a non-toxic polyvinyl chloride / wood flour / nanosilica nanocomposite obtained by mixing at a temperature of 0 ° C. and melt blending conditions of 40 to 70 rpm. Here, the wood powder is used after removing water from an oven at 100 ° C., and the PVC compound may be characterized by including 0.5 to 10 parts by weight of a non-toxic stabilizer, and a filler, an impact reinforcing material, and a pigment may be mixed.

Description

 Non-toxic polyvinyl chloride / wood flour / nanosilica nanocomposite with excellent dimensional stability {Heavy metal free-PVC / wood flour / nanosilica nanocomposites with good dimensional stability}

The present invention relates to a wood polymer composite (WPC), and more particularly to a non-toxic polyvinyl chloride (PVC) / wood flour / nano silica nanocomposites that can be prepared by adding silica to the nano-filler. .

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 for environmentally friendly recycling of a large amount of sawdust generated during 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 produced by extrusion or injection processing of such eco-friendly wood powder / polymer composite materials are widely used as a substitute to complement various disadvantages of building materials made of a single material made of wood or plastic. PVC, a thermoplastic resin used in the present invention, is widely used around us as a general purpose plastic, and has excellent mechanical, physical and chemical properties, high abrasion resistance, durability, chemical resistance, flame retardancy, and compatibility with various additives. Due to the characteristics, it is possible to make a variety of products from soft to soft products to hard products.

WPC as described above 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. The dimensional stability, which is affected by temperature, is judged by the large and small strain of the original object when the object is heated, that is, when the temperature is increased. Dimensional stability should be good due to the small strain of dimension due to temperature change. Building materials will repeatedly expand and contract as the ambient temperature changes, which can lead to warpage and cracking.

In addition, as the importance of the environment becomes more and more, some non-toxic PVC products have been released due to the exclusion of heavy metals, but physical properties such as dimensional stability are somewhat lower than those of conventional PVC products. Several studies are being conducted to solve this problem, but there is no clear achievement.

In order to solve the prior art as described above, the applicant discloses an environmentally friendly polyolefin / wood powder composite which improves the mechanical properties, thermal properties and flame retardancy of the WPC composite in Patent No. 10-681333, and also a patent filed under the name of the applicant. Application No. 2009-40025 discloses an environmentally friendly non-toxic vinyl chloride / wood powder / clay nanocomposite having excellent dimensional stability using clay, and another patent application No. 2009-58193 in the name of the present applicant discloses heat using polyolefin and clay. Although a composite having improved stability and dimensional stability has been disclosed, it is different from the present invention because it is different from each other in the purpose and use of the nanopillar.

An object of the present invention is to solve the problems of the prior art as described above, using nano silica as a nanofiller to improve the dimensional stability and using a stabilizer that does not contain heavy metals, it is useful for building interior and exterior materials eco-friendly and economically The purpose of the present invention is to provide a non-toxic-PVC / wood powder / nanosilica nanocomposite having excellent dimensional stability using nanosilica and a method of manufacturing the same.

The present invention to achieve the object of the present invention as described above;

A non-toxic polyvinyl chloride / wood flour / nanosilica nanocomposite comprising 1 to 80 parts by weight of wood powder and 10 parts by weight or less of nanosilica is provided by 100 parts by weight of the PVC compound.

Wherein the PVC compound is characterized in that it contains 0.5 to 10 parts by weight based on 100 parts by weight of PVC compound non-toxic stabilizer free of heavy metals, fillers, impact modifiers and pigments may be included as needed, the wood powder is 70 It is preferable to use a size of ˜150 μm, and the nanosilica is preferably used having a particle size of 100 nm.

The present invention also provides 1 to 80 parts by weight of wood powder of 70 to 150㎛ size and 10 parts by weight or less of nanosilica to an internal mixer in order to provide such a composite. After the addition, it provides a method for producing a non-toxic polyvinyl chloride / wood powder / nano silica nanocomposite, which is made by mixing at a temperature of 160 ~ 200 ℃ and melt blending conditions of 40 ~ 70rpm.

The wood powder is preferably used after removing the moisture in the oven at 100 ℃, the PVC compound is characterized in that it contains 0.5 to 10 parts by weight of a non-toxic stabilizer free of heavy metals, and fillers, impact modifiers and pigments can be mixed It may be.

PVC / wood flour / nanosilica nanocomposite according to the present invention can be mainly used as interior and exterior building materials, excellent dimensional stability and environmentally friendly. PVC / wood flour / nanosilica nanocomposite contains a lot of wood powder, so it is possible to use lumber and non-economical wood, which are generated when processing waste wood or natural wood, so it is not only eco-friendly but also heavy metal-free PVC compound, so it is eco-friendly. to be. As the importance of the environment has risen internationally, with the emergence of sick house syndrome and environmental hormones, consumers' interest in eco-friendly products has increased. Due to this, the demand for heavy metal-free PVC compounds also does not contain heavy metals. As well as the costs incurred during disposal, waste wood can be used and environmentally friendly in terms of using non-toxic PVC compounds that do not contain heavy metals. PVC / wood flour / nanosilica nanocomposites have similar texture and appearance to wood and have better processability than natural wood. Therefore, the PVC / wood flour / nanosilica nanocomposite according to the present invention can provide a product having the advantages of natural wood and plastic as well as satisfying consumer preferences.

1 is a graph of thermal analysis (TMA, Thermomechanical Analysis) results.
2 is a table summarizing the coefficient of thermal expansion and the dimensional change obtained from the thermal analysis experiment result graph (FIG. 1).

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

First, in the present invention, a non-toxic metal-free PVC compound is used. That is to say that the PVC compound is suitable for environmentally friendly using a stabilizer that does not contain heavy metals.

In the above PVC compound may be used by mixing a filler, an impact reinforcing agent and a pigment, in addition to the non-toxic stabilizer.

In addition, in the present invention, 1 to 80 parts by weight of wood powder having a size of 70 to 150 μm is mixed with respect to 100 parts by weight of the PVC compound, and the wood powder is surrounded by a polymer of PVC compound to form a complex having good physical properties. Can be. However, as the wood powder content increases, encapsulation by the PVC compound is limited. At this time, if the wood powder is not completely wrapped with the PVC compound, the absorption of water is increased and the product may be damaged by external bacteria or pests. It is preferable to use the above range because it significantly affects the appearance and color change as well as deterioration of the physical properties of the product.

The reason why the size of the wood powder is 70-150 μm is based on the use in the examples of the present invention, and commercially available commercially-available ones have been used.

In addition, in the present invention, the nanosilica is added to 10 parts by weight or less with respect to 100 parts by weight of the PVC compound, the particle size of the nanosilica is preferably 100nm or less in order to maximize the performance as a nanocomposite. In this case, when the content of nanosilica exceeds 10 parts by weight, aggregation may occur without dispersing in the PVC compound, which degrades the physical properties of the composite and causes the composite to become hard due to excessive brittleness. It is preferable to set it to 10 parts by weight or less because the endurance may be weakened.

Hereinafter, the present invention will be described through examples. The following examples are intended to illustrate the invention and are not intended to limit the invention thereto.

Example 1

The PVC compound used in this example is manufactured by mixing fillers, non-toxic stabilizers, impact modifiers and pigments using PVC (LS100E, K-Value = 67, polymerization degree = 1040 ± 50) of LG Chem. 80 parts by weight of wood flour (Lignocel C-120 of J. Retenmaier & Sohne Co., J. Retenmaier & Sohne Co.) was used after removing water from an oven at 100 ° C., and nano silica was used.

As hydrophilic fumed silica, 3 parts by weight of AEROSIL®OX50 (particle size 40 nm, specific surface area 50 m 2 / g) manufactured by Degussa, Germany, was used.

The PVC / wood flour / nanosilica nanocomposite specimens were mixed sufficiently until the torque was stabilized under melt blending conditions of 160 ~ 200 ℃ and 40 ~ 70rpm after adding PVC, wood flour, and silica into an internal mixer. The melt mixture was removed from the internal mixer, placed between hot presses, and a panel was produced by compression molding. Specimens for thermal analysis (TMA) tests were made by cutting panels. Each material was first dry blended and then put into an internal mixer.

Comparative example  One

PVC / wood flour WPC was prepared to exclude nanosilica for comparison with Example 1. As in Example 1, PVC compound was prepared by mixing PVC, LS100E, K-Value = 67, and polymerization degree = 1040 ± 50 of LG Chemical Co., Ltd. as a main ingredient, filler, non-toxic stabilizer, impact modifier, and pigment. 80 parts by weight of wood flour (Lignocel C-120, J. Retenmaier & Sohne Co., J. Retenmaier & Sohne Co.) were used after removing water from an oven at 100 ° C., but silica was not used.

Non-toxic PVC / wood powder WPC specimens are mixed with the non-toxic PVC and wood powder in an internal mixer until the torque is stabilized under melt blending conditions of 160 ~ 200 ℃ and 40 ~ 70rpm. The panels were made by compression molding after taking them out of the null mixer and placing them between hot presses. Specimens for thermal analysis (TMA) tests were made by cutting panels. Each material was first dry blended and then put into an internal mixer.

Nontoxic- PVC / wood flour / nanosilica nanocomposites of Example 1 ( PVC100 / Wood80 / nanosilica3 in FIGS. 1 and 2) and nontoxic-PVC / wood flour WPC ( PVC100 / Wood80 in FIGS. 1 and 2) of Comparative Example 1 Dimensional stability was measured using a thermal analyzer (TMA) and the results are shown in FIGS. 1 and 2. Figure 1 shows the change in the dimensions of the polyvinyl chloride / wood flour / nano silica ( PVC 100 / Wood 80 / nanosilica 3 ) nanocomposite according to the temperature change compared to the polyvinyl chloride / wood powder ( PVC 100 / Wood 80 ). Figure 2 shows the dimensional stability data of the polyvinyl chloride / wood flour / nano silica ( PVC 100 / Wood 80 / nanosilica 3 ) nanocomposite according to the present invention compared to polyvinyl chloride / wood powder ( PVC 100 / Wood 80 ). It can be seen that the dimensional stability of the nontoxic-PVC / wood flour / nanosilica nanocomposite of Example 1 is much better than the dimensional stability of the nontoxic-PVC / wood flour WPC of Comparative Example 1. Variables affecting the dimensional stability of PVC-based WPC nanocomposites may include the type of PVC, the content and type of wood flour, the amount of additives, the working temperature, the retention time in the extruder, and the content of nanosilica. And content will be the most influential variables. Even if the content of the nanosilica is constant, if the nanocomposite prepared by dispersing the nanosilica in which the particle size is very small and agglomerated well in the thermoplastic matrix will be further improved in dimensional stability.

Claims (4)

80 parts by weight of wood powder having a size of 70 to 150 µm, and 3 parts by weight of silica as a nanofiller of 100 nm or less, based on 100 parts by weight of PVC compound, wherein the PVC compound contains 0.5 to 10 parts by weight of a stabilizer based on 100 parts by weight of PVC compound. Polyvinyl chloride / wood powder / nano silica nanocomposite, characterized in that it contains. delete delete delete

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