JP2000343528A - Manufacture of woody resin composition, woody resin composition obtained thereby, and molded product of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of an offensive odor even in the case of using a sawdust of a wood material and a sander dust by limiting a stirring time in a temperature condition higher than a thermal decomposition temperature of a synthetic resin stuck to a cellulosic material to a specific time or less while a thermoplastic material is melted. SOLUTION: PB sander dust and polypropylene which are cast into a stirring blade type mixer 1 are stirred by stirring blades 13a-13f in a chamber 11. Thereby, they collide with each other, or collide with the stirring blades 13a-13f and a wall face of the chamber 11. Then, a friction heat is generated, and a temperature of the polypropylene being a thermoplastic plastic material is gradually raised. Then, in the case where a melting temperature of the thermoplastic plastic material is higher than a thermal decomposition temperature of a synthetic resin stuck to a cellulosic material, since a stirring time in a temperature condition higher than the thermal decomposition temperature of the synthetic resin is at most 3 min and short, thermal decomposition of the synthetic resin stuck to the cellulosic material can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a wood-based resin composition containing a cellulose-based material to which a synthetic resin is attached and a thermoplastic material.

[0002]

2. Description of the Related Art Conventionally, a thermoplastic material such as polypropylene or polystyrene and a cellulosic material such as wood flour have been charged into a stirring blade type mixer. A wood-based resin composition is produced by mixing a cellulose-based material with a thermoplastic material in a molten state while melting the thermoplastic material by frictional heat generated when the two are stirred in the machine. For example, a wooden composite board is formed using an object.

[0003] By the way, as a cellulosic material used in producing the above-mentioned woody resin composition, a material such as wood flour newly made from wood or the like is used. It is desired to use resources effectively by using wood saw such as plywood, PB, and MDF instead of pure cellulosic materials, sander dust, and the like.

[0004] However, the above-mentioned sawdust or sander dust of wood material such as PB has an adhesive such as urea resin used when manufacturing wood material adhered thereto. When a wood-based resin composition is manufactured by mixing crushed or sander dust with a thermoplastic material that has been melted while being crushed, urea that has adhered to the cellulosic material due to the heat of the molten thermoplastic material. There is a problem that an adhesive such as a resin is thermally decomposed to generate ammonia or an amine compound, and an unpleasant odor is generated in the process of producing the wood-based resin composition.

[0005] Further, since the ammonia and the amine compound generated in this manner are confined in the woody resin composition to be produced, when a molded article is produced using such a woody resin composition, There are problems that bubbles and nests are generated during extrusion molding, which causes roughening of the molded article, and that an unpleasant odor is emitted from the molded article even after molding.

Accordingly, an object of the present invention is to provide a method for producing a woody resin composition which does not easily generate an unpleasant odor even when sawdust or sander dust of woody material such as PB is used as a cellulosic material, and an object of the present invention. It is an object of the present invention to provide a woody resin composition to be obtained and a molded article of the woody resin composition.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a cellulose-based material to which a synthetic resin is adhered and a thermoplastic plastic material are charged into a stirring blade type mixer and stirred. Thus, while melting the thermoplastic material, while limiting the stirring time under a temperature condition higher than the thermal decomposition temperature of the synthetic resin attached to the cellulosic material to 3 minutes or less, the cellulosic material Is mixed with the thermoplastic material in a molten state.

When such a method is adopted, even if the melting temperature of the thermoplastic material used is higher than the thermal decomposition temperature of the synthetic resin adhered to the cellulosic material, the temperature is higher than the thermal decomposition temperature of the synthetic resin. Since the stirring time is as short as 3 minutes or less, the thermal decomposition of the synthetic resin attached to the cellulosic material can be minimized.

Therefore, when the urea resin is adhered to the cellulosic material to be used as in the production method according to the second aspect, thermal decomposition of the urea resin into ammonia and amine compounds is suppressed. Therefore, generation of unpleasant odor in the process of producing the wood-based resin composition can be minimized.

[0010] In addition, since the wood-based resin composition produced by the above-described method hardly incorporates a thermally decomposed substance such as ammonia or an amine-based compound, when the wood-based resin composition is extruded using the wood-based resin composition. Bubbles and nests are less likely to be generated, and a molded article with less rough surface can be obtained.
Dispersion of an unpleasant odor from the obtained molded article can be minimized.

Further, when the blending amount of the cellulosic material is set within the range of 50 to 80% by weight as in the production method according to the third aspect, it is possible to obtain from the produced woody resin composition. There is an effect that a texture close to that of a wooden material can be given to the molded product.

The synthetic resin adhering to the cellulosic material includes urea resins such as urea resins, melamine resins and urea melamine resins, as well as phenol resins.
In addition, as the “cellulosic material to which the synthetic resin adheres”, plywood sander dust, PB sander dust, MDF sander dust, waste MDF fiber, plywood sawdust, PB sawdust, MDF sawdust, and the like can be used.
Those having a particle diameter or a fiber length of 10 mm or less are preferred.
Further, it is preferable that the cellulosic material to be used is pelletized in advance from the viewpoint of workability, mixability, and the like, and a material to which a synthetic resin does not adhere may be mixed.

[0013] As the thermoplastic material,
Polypropylene (PP), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PE
T), acrylonitrile butadiene styrene copolymer (ABS), polyvinyl chloride (PVC), etc., and their waste plastics can be used alone or in a mixture of two or more types. A small amount of thermosetting plastic material may be mixed. When the thermoplastic material is crushed in the stirring blade type mixer, the thermosetting plastic material is also crushed into fine powder and dispersed in the molten thermoplastic material together with the cellulosic material. It does not matter.

In order to suppress the thermal decomposition of the synthetic resin adhering to the cellulosic material, it is desirable to minimize the stirring time under a temperature condition higher than the thermal decomposition temperature of the synthetic resin. Since it is necessary to consider the dispersibility of the cellulosic material with respect to the plastic material, the stirring time under a temperature condition higher than the thermal decomposition temperature of the synthetic resin is as short as possible in consideration of the performance of the mixer used. Must be set to time. Specifically, it is desirable to set the time within 3 minutes, preferably within 1 minute, more preferably within 30 seconds.

Further, a deodorant such as a metal catalyst (zinc oxide, copper oxide), activated carbon and sodium hydrogen carbonate, and a compatibilizer (eg, maleic anhydride) for strengthening the bond between the cellulosic material and the thermoplastic material. Modified polypropylene) and a lubricant (eg, wax, paraffin, butyl stearate, methyl stearate) for improving the fluidity of the mixture can be appropriately added.

Further, the molded wood-based resin composition is subjected to press molding, roll (continuous) press molding, extrusion molding or the like in a molten state to produce various molded articles such as a synthetic wood board. . Concretely, floor base materials and panel base materials for floor heating panels with hot water tube receiving grooves are suitable for press molding, and floor panels and control panels are suitable for roll press molding. , Exterior moldings (such as wood decks), building structural members (such as building pillars), construction materials (surrounding edges, sills, window frames, etc.) are suitable for extrusion molding. The floor panel and control panel can also be manufactured by press molding.

[0017]

Embodiments of the present invention will be described below. First, 120 g of PB sander dust to which a urea resin was attached as a cellulosic material and 80 g of polypropylene as a thermoplastic material were charged into a stirring blade type mixer 1 as shown in FIG. 1 and stirred for about 50 seconds.

As shown in the figure, a rotary shaft 12 horizontally supported by a bearing (not shown) penetrates through a chamber 11 having a horizontal cylindrical shape.
The rotating shaft 12 has six stirring blades 13a, 13b, 13
c, 13d, 13e and 13f are provided.

Of the six agitating blades 13a to 13f, the two agitating blades 13a and 13f at both ends prevent the molten thermoplastic material from adhering to the inner surfaces of both end walls of the chamber 11. In addition, it is attached to the rotating shaft 12 so as to slide on the inner surfaces of both end walls of the chamber 11.

On the other hand, four stirring blades 13b, 13c, 13d, 13e located in the middle of the chamber 11
Is used to increase the collision efficiency by guiding the input material to the center of the chamber 11 and to uniformly mix the materials. The materials are staggered on the outer peripheral surface of the rotating shaft 12, and the tip has an angle of about 15 degrees. Twisted.

The chamber 11 has a material supply port 1.
1a and a mixture discharge port 11b are respectively formed, and the material supplied to the hopper 15 is moved from the material supply chamber 16 to the material supply port 11a by a spiral material supply screw 14 provided on the outer peripheral surface of the rotating shaft 12. It is supplied to the inside of the chamber 11. The mixture discharge port 11b is closed by an open / close door (not shown).

The PB sander dust and the polypropylene fed into the stirring blade type mixer 1 are stirred by the stirring blades 13a to 13f in the chamber 11 to collide with each other or to collide with each other or to be stirred by the stirring blades 13a to 13f and the chamber 11. Frictional heat is generated by colliding with a wall surface of the thermoplastic resin, and the frictional heat gradually raises the temperature of polypropylene which is a thermoplastic material. The capacity of the stirring blade type mixer 1 used was 1 L, and the stirring blades 13 a to 13 f were rotated at a high speed so that the tip speed was about 30 m / sec.

When the polypropylene reaches the melting temperature by stirring, it melts in a gel state, and accordingly, the PB sander dust is uniformly dispersed while being caught in the molten polypropylene, and finally the polypropylene and the PB sander dust are uniformly dispersed. And the mixture is discharged from the mixture discharge port 11b as a gel-like wood-based resin composition.

Since the thermal decomposition temperature of the urea resin adhering to the PB sander dust is 170 ° C. and the melting temperature of the polypropylene is 165 to 170 ° C., the PB sander dust having the urea resin adhering to the molten polypropylene is removed. When the mixture is stirred, the urea resin adhering to the PB sander dust is thermally decomposed to generate ammonia and an amine-based compound.
By stirring for about 3 seconds under the above temperature conditions, PB sander dust can be uniformly dispersed and mixed in the polypropylene in a molten state, so that generation of ammonia and amine compounds due to thermal decomposition of the urea resin occurs. Was minimized, and no unpleasant odor was generated during the production process of the wood-based resin composition.

A wooden composite board was manufactured by cold-pressing the gel-like wooden resin composition thus obtained at a pressure of about 40 kgf / cm ² . This wooden synthetic board had excellent dimensional stability and sufficient physical strength, and no unpleasant odor such as amine odor was emitted from the formed wooden synthetic board.

(Comparative Example) 60% by weight of PB sander dust with urea resin adhered as a cellulosic material and 40% by weight of polypropylene as a thermoplastic material
Simultaneously put into a commonly used Henschel type stirring blade type mixer, stirring for 10 minutes by rotating the stirring blade at high speed so that the tip speed becomes about 30 m / sec,
A wood-based resin composition was produced by dispersing and mixing PB sander dust in polypropylene in a molten state.

In this Henschel type stirring blade type mixer,
PB sander dust with a small particle size rises in the mixing tank during stirring and mixing.
It took a certain amount of time to uniformly disperse and mix the B sander dust, and the mixture was stirred for about 8 minutes at a temperature not lower than the thermal decomposition temperature (170 ° C.) of the urea resin. As described above, since the urea resin is exposed to a temperature environment higher than the thermal decomposition temperature for a certain period of time, the urea resin attached to the PB sander dust is thermally decomposed, and an amine odor or the like is produced in the process of producing the wood-based resin composition. An unpleasant odor occurred.

A wooden synthetic board was manufactured by cold-pressing the gel-like wood-based resin composition thus obtained at a pressure of about 40 kgf / cm ² . Since the woody synthetic board contains ammonia and amine compounds generated in the process of manufacturing the woody resin composition, unpleasant odors such as amine odors were emitted from the formed woody synthetic board. .

As described above, a wood-based resin composition is produced by mixing a cellulose-based material to which a synthetic resin such as a urea-based resin is adhered and a thermoplastic material such as polypropylene. If the thermoplastic material has a high melting temperature and must be mixed under stirring at a temperature higher than the thermal decomposition temperature of the synthetic resin adhering to the cellulosic material, use these high temperature conditions. By suppressing the stirring and mixing time as much as possible, the generation of unpleasant odor due to the thermal decomposition of the synthetic resin adhering to the cellulosic material can be minimized. It is particularly important to select and use a mixer capable of uniformly mixing the thermoplastic material in a short time.

When the melting temperature of the thermoplastic material to be used is lower than the thermal decomposition temperature of the synthetic resin adhering to the cellulosic material, the temperature in the mixer becomes lower than the temperature of the synthetic resin adhering to the cellulosic material. By controlling the stirring speed and the like by a mixer so as not to raise the temperature above the thermal decomposition temperature, it is possible to prevent generation of unpleasant odors in the production process of the wood-based resin composition and emission of unpleasant odors from molded products Can be. Plywood sander dust, PB sander dust, MD
F sander dust, waste MDF fiber, plywood sawdust, P
Since urea resin as an adhesive is usually attached to B sawdust, MDF sawdust, etc., polyethylene, polystyrene, polyvinyl chloride, etc., whose melting temperature is lower than the thermal decomposition temperature of urea resin, can be used as a thermoplastic material. This is effective when used as

In the above-described embodiment, the blending amount of PB sander dust, which is a cellulose-based material, is 60% by weight. However, the blending amount of the cellulose-based material is determined in consideration of physical properties required for a final molded product. Therefore, it may be appropriately set within the range of 50 to 80% by weight. Cellulose-based compounding amount is 5
If the amount is less than 0% by weight, the texture of the wood material cannot be imparted to the final molded product. If the amount of the cellulosic material is more than 80% by weight, the amount of the thermoplastic material functioning as a binder is too small. This is because sufficient strength cannot be ensured for the final molded product.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a stirring blade type mixer used for carrying out a method for producing a woody resin composition according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stirring blade type mixer 11 Chamber 12 Rotation axis 13a, 13b, 13c, 13d, 13e, 13f Stirring blade 14 Material supply screw 15 Hopper 16 Material supply chamber

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jiro Nishio 2-10-60 Hirabayashi-minami, Suminoe-ku, Osaka-shi, Osaka Inside Eidai Sangyo Co., Ltd. (72) Inventor Akira Nakamura 2 Hirabayashi-minami, Suminoe-ku, Osaka, Osaka No. 10-60, Eiji Daigyo Co., Ltd. (72) Eiji Yamano 2-10-60, Hirabayashi Minami, Suminoe-ku, Osaka City, Osaka Prefecture F-term in Eiji Daigyo Co., Ltd. 4F201 AA01 AA38 AR06 AR11 AR15 BC01 BC02 BC12 BC37 BD02 BD05 BK15 BK73 BM06 BM14 BN15 4J002 AH00W BB03X BB12X BC03X BD04X BN15X CF06X FA04W FB26W FD200 GL00

Claims (5)

[Claims] 1. A synthetic resin-attached cellulose-based material and a thermoplastic material are put into a stirring blade type mixer and stirred to adhere to the cellulose-based material while melting the thermoplastic material. A wood-based resin composition in which the cellulosic material is mixed with the molten thermoplastic material in a state where the stirring time under a temperature condition higher than the thermal decomposition temperature of the synthetic resin is limited to 3 minutes or less. Method of manufacturing a product. 2. The method for producing a wood-based resin composition according to claim 1, wherein the cellulosic material to which a urea-based resin is adhered is used. 3. The method according to claim 1, wherein the amount of the cellulosic material to which the synthetic resin adheres is 50 to 80% by weight. 4. A wood-based resin composition produced by the method according to claim 1. 5. A molded article molded using the woody resin composition according to claim 4.