JPH1170508A - Wooden synthetic material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reutilize a thermoplastic synthetic resin product of every kind to recycle the same as a wooden synthetic panel by respectively compounding a cellulosic crushed material such as wood flour or the like, a resin and a dispersion accelerator in a specific amt. ratio and crosslinking the cellulosic crushed material and the resin through the dispersion accelerator. SOLUTION: A cellulosic crushed material with a moisture content of 0.3 wt.% and an average particle size of 50-300 meshes (about 300-50 μm) such as wood flour and a resin are compounded in a wt. ratio of 50-60% and a dispersion accelerator is compounded in an amt. of 0.3-1.0% by wt. of the wood flour and the resin to crosslink the cellulosic crushed material and the resin through the dispersion accelerator. Further, it is pref. to compd. 50-60 wt.% of the wood flour as the cellulosic crushed material and 50-40 wt.% of polycarbonate, nylon or PVC as the resin. Furthermore, if titanium oxide is compounded in an amt. of 25% or less by wt. of the wood flour, coloration and the yellowing of wood can be prevented. As the resin, a waste material of a thermoplastic synthetic resin product can be reutilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a woody synthetic material composition using a cellulose-based crushed material such as wood flour as a main molding material. The present invention relates to a woody synthetic material composition suitable for use in extruding and kneading with an extruder to form a predetermined thickness or an arbitrary shape from a forming die.

In particular, one or both of the above-mentioned cellulosic crushed material and resin are used for building waste materials, automobiles,
With the diversification of life, including home appliances, various types of thermoplastic synthetic resin products that have been used in large quantities and used in large amounts for a wide range of applications, such as daily necessities, The present invention relates to a means for providing a woody synthetic material composition for recycling as a woody synthetic board.

[0003]

2. Description of the Related Art Conventionally, various types of molded resin products based on wood flours have been developed for the purpose of improving water resistance, heat insulation, and the like. From the standpoint of securing forest resources, rising timber costs, and the perceived persistent demand for timber products, the development of such wood composite boards has been demanded. Kaihei 7-266
No. 313.

[0004]

Conventionally, in this type of woody synthetic board, as the amount of wood flour is increased in order to enhance the woody feel, the water absorption and the coefficient of linear expansion increase, and the desired strength is obtained. For some applications, such as interior materials for houses and other architectural structures or interior materials for various vehicles, it is not always possible to completely meet demand.
The main cause is, for example, when mixing and molding cellulose-based crushed material such as wood flour obtained by grinding wood, fluidity of the cellulose-based crushed material, dispersibility of wood powder and resin material, It can be mentioned that the properties of the wood flour have a great influence on extrusion molding.

[0005] That is, the high frictional resistance during the flow of the wood flour and the poor compatibility with the resin material cause the wood flour structure in the formed wood composite board to be coarse and dense, resulting in uneven density. In addition, when the extruder is filled with wood flour and resin and heated, this causes roughening of the surface of the formed wooden composite board itself, bubbles, nests, and the like. Thus, it is possible to improve the familiarity between the wood flour and the resin and maintain a good kneading state at the time of molding as a wood synthetic board using the wood synthetic material composition. Thus, the frictional resistance of wood flour was reduced, and this was a major factor in forming a uniform and dense wood composite board. However, conventionally, it has been a problem to improve the familiarity between wood powder and resin.

[0006]

In order to achieve the above object, the woody synthetic material composition of the present invention has a water content of 0.3%.
wt% or less and an average particle size of 50 to 330 mesh (about 300
５０50μm) Cellulose crushed material such as wood flour and resin
６０60 wt%, and 0.3 to 1.0% of a dispersion accelerator based on the wood flour and the resin. The cellulose crushed product and the resin are mixed via the dispersion accelerator. It is characterized by being crosslinked. It is also preferable to mix 50 to 60 wt% of wood flour as a cellulosic crushed product and 50 to 40 wt% of polycarbonate, nylon or PVC as a resin.

[0007] If the water content is 0.3 wt% or more, molding becomes extremely difficult at the time of extrusion or injection molding, and the compatibility between the wood powder and the resin becomes poor, and kneading becomes insufficient.

[0008] The mixing ratio with wood powder, including the case where the resin is PP, is such that when the wood powder is less than 50 wt% of the total amount of the raw materials, the resin may become a somewhat large lump in the mixer. Is preferably more than 50% by weight. When the amount of the wood powder is less than 50% by weight, it becomes difficult to adsorb and fuse the resin, the dispersion promoting agent, and the titanium oxide to the wood powder of the above-mentioned composition, and the mechanical properties, particularly the bending strength, become low. No result. In addition, wood flour is 60wt%
Until the above, the raw material can be gelled, and if the wood flour exceeds 60% by weight, the wood flour will burn during molding, making the molding difficult, and even if the molding can be performed, the strength will be reduced.

[0009] Further, when the particle size is 50 mesh or more, the evaporation of moisture is not performed smoothly, and the dispersion is not uniformly performed during kneading.

[0010] When the mesh size is less than 330 mesh, special pulverization using a ball mill or the like is required, and the efficiency is poor. In addition, the tissue such as the conduit in the wood flour fibers is broken, and it is difficult to crosslink with the resin. is there.

Further, if a dispersion accelerator is added in an amount of 1.0% or more, molding becomes difficult, and when a plate having a certain thickness or more is formed, an undesirable result such as a decrease in bending strength may be brought about. If it is 0.3% or less, the effect of improving characteristics is not exhibited.

If titanium oxide is blended at 25% or less with respect to the wood flour, coloring and burning of the wood flour can be prevented. If the content of titanium oxide is 26% by weight or more, adsorption to the cellulosic crushed material becomes slightly difficult, which is not appropriate.

The resin is PVC (polyvinyl chloride),
PET (polyester), PP (polypropylene), P
One kind of resin such as C (polycarbonate) and nylon or a mixture of several kinds of these can be used.

The resin may be a recycled resin obtained from the waste material of a thermoplastic synthetic resin product, or a virgin resin may be charged, or the virgin resin and the recovered resin may be, for example, 50% each. It can also be used.

[0015] In addition, it is preferable to mix titanium oxide by up to 25% with respect to the wood flour in order to further increase the shearing force. Further, the titanium oxide has good fluidity and good dispersibility in a solution, and contributes to increasing the compression modulus of the woody synthetic board of the present invention.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Production Example of Wood Synthetic Material Composition In this example, 55 wt% of the raw material is 100 mesh (about 20%).
0μm) 25kg of wood powder with a passing particle size and a bulk specific gravity of 0.2
(Wood flour contains about 8 wt% of water at this time) 45 wt% is 20.45 kg of resin PP (polypropylene), 0.5% compatibilizer for wood flour and PP as a dispersion promoter, about 2 wt%
28 g.

The average particle size of the wood flour means a particle size of 50 weight percent in the cumulative weight percent distribution of the wood flour.

The wood flour and the titanium oxide are mixed for about 2.
5kg (the ratio to wood flour is about 10%)
% PP (polypropylene), wood flour as a dispersion promoter,
0.5% compatibilizer to PP and titanium oxide, about 24%
0 g may be blended.

The wood flour or the wood flour and titanium oxide are simultaneously charged, and at a temperature of about 180 ° C. due to frictional heat generated by shearing force of a stirring impeller rotating at high speed in a mixer,
The water content is 0.3 wt% or less, preferably 0.1 wt% or less. In this process, if titanium oxide is added at the same time as wood flour, some titanium oxide adheres to and penetrates around the fine wood flour or in some hollow or temporary pipes where water evaporates. Fix it.

Here, PP (polypropylene) as a resin and a compatibilizer are charged into a mixer.

In this embodiment, the form of the resin is 3 mm in diameter.
Pellet composed of granular material of about mm size is used. The compatibilizer is a reactive polyolefin-based oligomer (melt viscosity of about 7000 CPS: BL type viscometer, softening point of about 1
45 ° C .: JIS-K2531) was used. Specifically, it is Sanyo Chemical Industries, Ltd. Umex 1010.

In this step, the temperature in the mixer is 20
When the temperature rises to 0 ° C., kneading and melting are completed.

In this step, the PP does not become a large lump due to the wood powder in the raw material, and does not agglomerate during mixing and dispersion, but gels into a clay-like form just before coagulation.
It became a massive "kneading material" of about 100 mm. In other words, this lump means that individual wood flour permeates the entire surface of the wood flour alone and some of the resin also penetrates into some hollow or temporary pipes where the water in these micro wood flours evaporates. It adheres and is recrystallized between the resins fused to these wood flours via a compatibilizer, or is formed into a crosslinked state in which the resins are recrystallized to solidify adjacent fine particles. ,
The bond of the whole mass itself is brittle. Therefore, the kneaded material formed in this step is a good material that can be kneaded more efficiently by an extruder in a subsequent step, and is a good material that reduces the frictional resistance of wood powder particularly during extrusion.

More specifically, the water content of the wood flour is 0.3 wt% or less, so that the function of the compatibilizer to improve the dispersibility is further promoted. It is dispersed at a uniform density in the resin as viewed from the wood powder, and is kneaded and melted in such a manner as to be easily impregnated into the wood powder and completely surround the outer periphery of the wood powder as viewed from the resin.

The kneaded material formed by the mixer described above is cooled while stirring, and granulated to a diameter of about 25 mm or less.
Further, it is sized using a cutter mill to a particle size of 10 mm or less to form a pellet-like "woody synthetic material composition".

Using the above composition, a wood composite board was produced with a single-screw extruder having a diameter of 65 mm.

The above wooden composite board W: 910 mm, H:
4.0mm is cut every 1820mm by shearing,
Obtain a wood composite board.

Such a thin plate is a material for a wide range of uses as various building materials, furniture materials, equipment parts and the like. For example, the above-mentioned thin wooden composite board is used as a building material such as a decorative board for interior decoration of a house, or processed into a size of about 300 mm square to be used as a floor material such as a flooring block. Further, as another application, as an interior material in a car, for example, used as a decorative panel around a meter panel in a driver's seat, a decorative panel around a transmission, a decorative panel on other vehicle interior walls,
You can get a sense of quality. As a device part, it is used as a box panel of an electric device or the like or a decorative plate of another device.

Therefore, the woody synthetic material composition of the present invention can form a wide range of thick woody synthetic boards ranging from a thin plate to a thick plate, and a material for a wide range of uses can be formed.

The woody synthetic board formed from the woody synthetic material composition of the present invention has a high density, so that a large amount of wood flour can be mixed therein. Wood composite board is formed. Also. A wood composite board mixed with a large amount of wood flour is an excellent board material having properties close to those of a natural wood panel.

[Example] Comparative example of wood composite board 55% wood powder and 45% PP (additive: compatibilizer 0.5
%; Wood flour + PP + titanium oxide and titanium oxide 10
%; Wood flour) using a wood-based synthetic material composition of the present application (board thickness: 12.0 mm) (hereinafter referred to as “application example”).
And Comparative Example A (12.0 m thick) molded from a composition (but not containing a compatibilizer) produced in the same manner as in the above Production Example.
m) were subjected to the following physical property tests.

Linear expansion coefficient Test condition: JIS; A1325-1995

[0033]

[Table 1]

From the above results, compared with the conventional wooden composite board,
It was found that the change due to heat was extremely small and the dimensional stability was excellent. Then, Comparative Example B of MDF (sheet thickness 12.
0 mm) and Comparative Example C of OSB (plate thickness 12.0 mm) were subjected to the following physical property tests. Water absorption test Test conditions: Each test piece of 15 × 50 mm was immersed in pure water,
The mass change (= water absorption) after standing at 24 ° C. for 24 hours was measured.

[0035]

[Table 2]

From the above, the water absorption of the example of the present application showed an extremely lower value than any of Comparative Example A, Comparative Example B and Comparative Example C. The fact that the water absorption is easy to change means that the rate of change of the expansion and contraction of the board is large, that is, the dimensional change of the board is large due to environmental changes such as humidity, which is a factor that tends to cause cracks and dimensional irregularities of the board .

Specific Gravity, Flexural Modulus and Flexural Strength Test Test Conditions Spacing Distance: 100 mm, Test Speed: 5 mm / min

[0038]

[Table 3]

It was found that the board made of the woody synthetic material composition of the present application had practical bending elastic modulus and bending strength.

Wood screw holding force Test conditions Test piece Approx. 50 × 50 mm Wood screw: Approx. Φ3 mm (Prepared hole 2 mm)

[0041]

[Table 4]

From the above, the pull-out strength of the wood screw of the present example was higher than any of Comparative Example A, Comparative Example B and Comparative Example C. In addition, the hooking strength of the wood screw of the example of the present application is comparative example A in both the vertical direction and the horizontal direction.
The values were higher than those of Comparative Examples B and C.

The pull-out strength of a wood screw is considered to be related to the shearing force of the tissue of the plate, unlike the frictional force of the tissue of the plate around the nail as in the case of the pull-out strength of the nail.
That is, in the case of a wood composite board, it is considered that the adhesiveness between the structure of the board at the portion cut into the screw and other tissues is reflected in the strength of the pull-out strength of the wood screw.

The woody synthetic board of the present invention has a high adhesion between individual wood flours because the wood flour is uniform and high in density, and as shown in the examples of the present application, the wood screw pulling strength and the wood screw hooking strength are each different. Excellent results, higher than the comparative example, were obtained.

Comparative Example of a Wood Synthetic Board Using the Wood Synthetic Material Composition The wood synthetic board (sheet thickness: 4.0 mm) of the present application having the composition shown in the following table and Table 5 (hereinafter referred to as “Application Examples 1-4”) ) And Comparative Examples 1 and 2 (sheet thickness 4.0 mm) formed from a composition produced in the same manner as in the above Production Example and containing no compatibilizer, and further subjected to the following characteristic tests.

The size of the test piece is 12 × 12 cm to 20 ×
30cm.

[0047]

[Table 5]

The characteristic values shown in the following Tables 6 and 7 are based on the following test results.

Tensile test according to DIN 53455 (v = 2 mm / min) Bending test according to DIN 53452 (v = 2 mm / min) Compression test according to DIN 53454 (v = 2 mm / min) From the test results, polypropylene was blended in terms of bending properties and tensile properties. The wooden synthetic molded article (hereinafter referred to as “PP compound”) is a polyethylene-containing wooden synthetic molded article (hereinafter, “PP compound”).
It is called "PE blend". ) Is better. With and without the addition of titanium oxide, except that the compression modulus showed a high value,
P and PE blends (both collectively referred to simply as "both blends") were hardly affected, but both blends increased the tensile strength by 100% due to the addition of the compatibilizer. , The bending strength increased by about 60%, and the compression modulus and the compression strength increased by about 40% and 20%, respectively. Young's modulus was 30 for each of the PP blend and the PE blend.
% And 50%, with a clear improvement.

However, there is almost no effect on the flexural modulus.

[0051]

[Table 6]

[0052]

[0053]

[Table 7]

[0054]

[0055]

[Table 8]

[0056]

[Table 9]

The graph in FIG. 1 and the above Tables 8 and 9
Are water absorption and expansion in the thickness direction due to moisture after storage in distilled water for 4 weeks according to DIN53595, tensile test with DIN53455 (v = 2 mm / min) after storage in water for 4 weeks, and D
The test results of the bending test according to IN53452 (v = 2 mm / min) are shown.

By the addition of the compatibilizer, the water absorption was reduced to 1/3 of Comparative Examples 1 and 2 to which no compatibilizer was added. Swelling due to moisture was reduced by about 60%. On the other hand, Examples 1 and 3 of the present application to which titanium oxide was added were Examples 2 and 3 of the present application where no titanium oxide was added.
It is about 30% higher than 4

Further, by adding the compatibilizer, the water absorption becomes
Since it is low, the effect of moisture on the mechanical properties of these examples is small. That is, in both PP and PE blends, the Young's modulus and flexural modulus decreased by about 15% in the blend with the compatibilizer due to moisture, but decreased by about 40% in the blend without the compatibilizer.

The reduction in tensile strength and bending strength was reduced by about 15% in the whole company and about 20% in the latter.

The addition of titanium oxide has no effect on the decrease in mechanical properties due to moisture.

Next, the following test was conducted to examine the characteristics of both blends by freeze-thaw.

The following Tables 10 and 11 show the test results.

Step 1: Storage for 10 days in distilled water.

Step 2: Stored at -30 ° C for 16 hours, then at 23 ° C for 8 hours.

Step 2 was repeated 1, 3 and 10 times to measure and examine the characteristics.

In flexural modulus, both blends with the compatibilizer added were:
Almost unaffected by freeze-thaw cycles.
On the other hand, the blends without the compatibilizer (Comparative Examples 2) both had a decrease in flexural modulus of about 25%. On the other hand, the PE blend was hardly affected by the bending strength.

In the PE blend, the flexural modulus decreased by about 25% and about 35%, respectively, in the blend with and without the compatibilizer. However, the bending strength of the blend with and without the compatibilizer was reduced. The effect was milder, at about 5% and about 10%, respectively.

[0069]

[Table 10]

[0070]

[Table 11]

Next, the fractured portions of the samples subjected to the tensile tests of the present application example and the comparative example were observed with an electron microscope, and the influence of the compatibilizer on the microstructure in those structures was examined.

FIG. 2 shows the surface of the fractured portion of Comparative Example 2 (polypropylene containing no compatibilizer), in which the surface of the wood flour fiber which appears to be raised in the center is completely smooth and the resin does not adhere to the fiber surface at all. In addition, fiber rupture does not occur as each fiber rupture, but occurs at the interface with the resin. On the other hand, in FIG. 3 showing Example 2 of the present application (polypropylene blend without compatibilizer and without titanium oxide), the interface of the polymer at the fractured portion was broken together with the fiber, and the affinity at the interface with the fiber was improved. As a result, uniform and stable dispersion is achieved, and the interfacial adhesive strength is dramatically improved. Therefore, as shown in FIG. It can be seen that one fiber is broken. In Comparative Example 2, the extremely fragile interface became a defect,
It is considered that this was a factor in lowering the mechanical strength as compared with the example of the present application.

Further, each sample was polished on a surface perpendicular to the extrusion direction, and the samples were immersed in a red solution (safranin) at 18 ° C. for 12 hours. It was found that safranine was absorbed on almost all surfaces, mainly on the portion not dispersed in the, whereas in Example 2 of the present application, safranine was hardly absorbed.

[0074]

Since the present invention is configured as described above, it has the following effects.

The woody synthetic material composition of the present invention improves the conformability of the resin, and when gelling and kneading, the resin impregnates the cellulosic crushed product without agglomeration during mixing and dispersion,
Furthermore, since it adheres to the entire surface, the so-called resin is thermally,
Gives good fluidity so that the state of being fixed to chemically stable wood flour particles can be constantly maintained and the mixing and dispersion state of wood flour and resin is uniformly and constantly maintained. A woody synthetic material composition is formed, and an extruder is used to form an extruded dough in a good kneaded state by using the woody synthetic material composition. This can prevent damage and contribute to forming a uniform and high-density woody composite board.

Further, in the woody synthetic material composition of the present invention, since the water content of the crushed cellulosic material was controlled to 0.3 wt% or less, the addition of a compatibilizing agent reduced the linear expansion coefficient which has not been reported so far. Thus, dimensional stability comparable to non-ferrous metals can be provided, and strength can be dramatically increased.

[Brief description of the drawings]

FIG. 1 shows Examples 1, 2, 3, and 4 of the present application and Comparative Examples 1 and 2
The figure which shows the characteristic which appears as swelling in the thickness direction by the water | moisture content after storing in water for a week.

FIG. 2 is an electron micrograph of a fracture surface of Comparative Example 1.

FIG. 3 is an electron micrograph of a fracture surface of Example 2 of the present application.

FIG. 4 is an electron micrograph of a fracture surface of Example 2 of the present application.

[Procedure amendment]

[Submission date] October 31, 1997

[Procedure amendment 1]

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[Procedure amendment 2]

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[Correction method] Change

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[Procedure amendment 3]

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──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 1/00 C08L 1/00 // (C08L 1/00 101: 00)

Claims (4)

[Claims] 1. A method for mixing a cellulose-based crushed material such as wood powder having an average particle diameter of 50 to 330 mesh with a resin in a proportion of 50 to 60 wt% with a water content of 0.3 wt% or less, A wood-based synthetic material composition comprising 0.3 to 1.0% of a dispersing accelerator based on the mixture, and the cellulose crushed product and the resin being crosslinked via the dispersing accelerator. 2. Cellulose-based crushed material, wood flour 50 ~
60wt% and resin as polypropylene, polyethylene,
Polycarbonate, nylon or PVC 40-50wt
% Of the woody synthetic material composition. 3. The woody synthetic material composition according to claim 1, wherein titanium oxide is blended in an amount of 25% or less with respect to the wood flour. 4. The woody synthetic material composition according to claim 3, wherein a dispersion accelerator of 0.3 to 1.0% is added to the wood flour, the resin and the titanium oxide.