JP5042932B2 - Multi-layer extrusion molding with wood texture - Google Patents

Description

  The present invention relates to a multilayer extruded product having a surface layer excellent in wood texture and weather resistance.

In the trend of monotonous and artificial synthetic resin products to nature-oriented, in the building materials field, the orientation toward wood-tone is further progressing. As a technology for wood tone, initially, wood grain printing on the surface of a synthetic resin product and further low foaming technology have been used. In recent years, in addition to the wood tone, an extrudate product mixed with wood flour, which is molded by mixing wood with resin in order to increase environmental awareness and obtain a further wood texture, has started to appear on the market. By mixing wood into the resin, not only a more advanced wood-like texture can be obtained, but also physical properties such as the strength and thermal expansion coefficient of the molded product, and workability such as sawing and nailability are improved. is doing. On the other hand, due to the mixing of wood, the material discoloration tends to become noticeable when exposed to ultraviolet rays or moisture. Further, even synthetic resin products based on ABS resin, PS resin, or the like that do not mix wood, such as building materials, discoloration occurs due to insufficient weather resistance of these resins.
In addition, a technique for applying a sanding treatment to a synthetic resin molded body mixed with wood powder and performing printing (for example, refer to Patent Document 1 and Patent Document 2) or painting is also known (for example, Patent Document 3). reference).
JP-A-61-108502 (Claims) JP-A-61-100408 (Claims) JP 2001-353707 A (Claims)

  The present invention is intended to improve weather resistance in an extruded product having a wood-like texture using a synthetic resin mixed with wood powder as described above or having insufficient weather resistance. Therefore, it is intended to provide a synthetic resin-based molded article, particularly an extrusion molded article, which imparts an excellent wood texture and has excellent weather resistance.

The present invention, by a surface layer material the surface of the multilayer extrudate comprising a surface layer material and the substrate based resin superior wearing color resin in weather resistance has been sanded processed, fine irregularities are formed The present invention relates to a multilayer extruded body having a wood texture with a matte surface .
According to the present invention, the above-mentioned seeds are incorporated into the surface layer material by extruding a surface layer resin containing a colorant and having a MFR value lower than the MFR value of the surface layer base resin mixed with the base resin. The present invention relates to the above multilayer extruded product on which a pattern made of an agent resin is formed.

  The multilayer extruded product of the present invention in which the weather resistant resin layer is used as a surface material and the surface thereof is subjected to sanding treatment or further subjected to wood grain printing and clear coating expresses a wood texture that is not conventional and has excellent weather resistance. As a base material for multilayer molding, those containing wood powder or foams are excellent in lightness and workability in addition to the above characteristics, so that they can also be used as building materials, especially exterior wall materials used outdoors. Useful.

The present invention performs multilayer molding using a synthetic resin layer or a synthetic resin layer mixed with wood powder as a base layer and a resin material having excellent weather resistance as a surface layer, and sanding the surface to express a wood texture and weather resistance Is to improve. Hereinafter, the present invention will be described in more detail.
The multilayer extruded product having a wood texture of the present invention can be produced by co-extrusion of the base material layer and the surface layer material. As the surface layer material, a synthetic resin excellent in weather resistance, which is toned in the same color as wood, is used. Examples of the resin having excellent weather resistance include PMMA resin, AAS resin, AES resin, and MS resin.

In order to produce a wood grain pattern and to express the wood texture more effectively, it is possible to perform extrusion molding by mixing a colored seed resin with a base synthetic resin for the surface layer. The seed resin is preferably a resin having a lower MFR value than the base resin. Since the seed resin has lower fluidity than the base resin, it is not uniformly mixed with the base resin in the extrusion molding kneading process. A streak pattern that does not appear can be formed to give an appearance similar to wood grain.
The type of resin used as the seed agent is preferably the same as the base resin or a resin compatible with the base resin. For example, when the base resin is PMMA, the compatible resin corresponds to ABS, AAS, AES, or the like.
As a colorant for the seed resin, a general inorganic pigment having excellent weather resistance is used.
The mixing ratio of the seed resin to the base resin is preferably 0.2 to 10% by weight, more preferably 0.5 to 5% by weight, based on the base resin.

  Moreover, the surface layer material may contain a filler. By containing the filler, the surface layer material can be made opaque, and it becomes easier to express the wood texture. As fillers to be mixed for this purpose, those usually used as fillers for synthetic resins can be used, and examples include calcium carbonate, talc, mica, silica, glass beads, wollastonite and the like. The mixing amount of the filler is not particularly limited as long as it does not impair the extrusion moldability.

The base material constituting the multilayer extrusion-molded body maintains the shape of the molded body and determines the physical properties of the molded body. The base material may be a synthetic resin in which wood powder is mixed, a low foaming synthetic resin, a low foaming synthetic resin in which wood powder is mixed, or a solid synthetic resin. The former three are particularly preferable in terms of workability such as sawing and nailing and lightness. Further, the substrate may be any of a flat plate, an irregular cross section, and a shape having a hollow portion.
The base material layer containing wood powder preferably contains 10 to 85% by weight, preferably 40 to 65% by weight of wood powder with respect to the thermoplastic synthetic resin constituting the base material.
The resin used for the substrate is not limited as long as it can be extruded. For example, acrylonitrile / butadiene / styrene copolymer resin (ABS resin), acrylonitrile / styrene copolymer resin (AS resin), polystyrene resin (PS resin), high impact polystyrene resin (HIPS resin), polyvinyl chloride resin (PVC resin), polybutylene terephthalate resin (PBT resin), acrylonitrile / ethylene propylene rubber / styrene copolymer resin (AES resin), polyethylene terephthalate resin (PET resin), polycarbonate resin (PC resin), etc. can be illustrated. Particularly preferred resins are ABS resin, PS resin and PVC resin.

The sanding treatment applied to the surface layer material surface can be performed using a polishing apparatus such as a belt sander or a drum sander. The sanding process is performed by bringing an abrasive that rotates in a direction opposite to the conveying direction of the molded body into contact with the surface layer material surface of the molded body while conveying the molded body to be processed at a constant speed. Sanding can be performed after the molded body has solidified on the same line following extrusion molding, or it can be extruded, cut to a certain length, accumulated as a molded body, and then performed on another line. Good.
By the sanding process, streaks in one direction are randomly formed on the surface of the surface material, and a wood tone is developed. When a small amount of filler is added to the surface layer material, the filler appears on the surface by sanding and the wood texture is emphasized. Also, if the rotating abrasive is slightly swung, the polishing marks become irregular, resulting in a more natural finish.

The abrasive preferably has a roughness of # 20 to # 400, and particularly preferably # 40 to # 320.
The rotational speed of the abrasive is preferably 2 to 30 m / sec, particularly 2 to 15 m / sec as the surface speed. The compact conveyance speed is preferably 0.5 to 20 m / min, particularly 2 to 10 m / min.

  The multi-layer extrusion molded body subjected to the sanding treatment already has sufficient wood texture and excellent weather resistance, but may be further subjected to wood grain printing from above the sanded surface material. Wood printing is, for example, printing a pattern portion corresponding to an annual ring pattern of wood, and the obtained product expresses a more preferable wood texture by combining the pattern by sanding and the printed pattern. The printing process is preferably, for example, a method in which a paint is attached to a roller with a wood grain pattern and the wood pattern paint is once attached to a transfer roller and then transferred to the surface material of the molded body, but is not limited thereto. is not. In order to protect the printed wood grain pattern from peeling due to physical force and ultraviolet rays, it is preferable to apply a clear or matte clear paint.

Since the multilayer extruded product having the wood texture of the present invention thus obtained has fine irregularities formed on the surface, the light is irregularly reflected, the gloss is lost, and the surface becomes matte. Furthermore, if fine streak-like grooves are randomly carved in a certain direction, the appearance and feel of wood fibers will appear. Such surface non-glossiness, appearance and touch are the points of wood texture.
In addition, the wood texture becomes deeper by adding the filler to the surface layer material and / or printing the wood on the processed surface with the wood texture.

[Example]
Hereinafter, the present invention will be described in more detail and specifically by way of examples.
Example 1
(1) Preparation of resin composition for base material and surface layer material
Resin composition for base material-ABS resin containing 55% by weight of wood flour (non-foamed)
The following components (wood flour, ABS resin, additives)
Wood flour (average particle size 200μm) 55% by weight
ABS resin powder 34% by weight
AS resin powder 5% by weight
Magnesium stearate 4% by weight
Polyethylene wax 2% by weight
Was put into a Henschel mixer and mixed for 3 minutes at a blade rotation speed of 1770 rpm using a normal powder mixing blade. The obtained powder mixture was gelled and kneaded under the following extrusion conditions using the following biaxial kneader-extruder, and the extruded product was granulated into pellets with a hot cutter.
Twin-screw kneading extruder: Type “TEX30” manufactured by Nippon Steel Works,
30mmφ screw Cylinder temperature: 180 ℃
Screw rotation speed: 60rpm (same direction)
Screw structure: Combination of full flight and kneading Cylinder barrel: Two vent holes are provided, heating the cylinder,
Moisture contained in the wood flour is removed by kneading the screw.
Resin composition for surface layer-colored PMMA resin 100 parts by weight of PMMA resin is mixed with 2 parts by weight of bengara, 0.8 part by weight of titanium yellow, and 0.2 part by weight of carbon black, and is colored in the same color as wood. It was set as the pellet like the said base resin composition.

(2) Extrusion molding of multilayer molded body Using the above-mentioned surface layer material and pellets of the base material composition, two-layer profile extrusion molding was performed under the following conditions:
Extruder for base material: screw diameter 50 mmφ, L / D = 28
Surface layer material extruder: Screw diameter 40 mmφ, L / D = 20
Cylinder temperature: average 170 ° C, dice 190 ° C
Screw rotation speed: 10rpm
Molded body shape: described in FIG.
Width 160mm x height 30mm (wall thickness 10mm).

(3) Sanding treatment of the surface of the molded body A sanding treatment was performed on the surface layer of the extruded molded body (flat plate) using a belt sander. The molded product coming out of the extrusion molding machine is cut to a predetermined length, and the cooled product is placed on a conveyor belt and conveyed in the longitudinal direction of the molded product, while rotating in the direction opposite to the traveling direction of the molded product. Sanding was performed on the surface of the molded product with the polishing belt of the belt sander. The sanding conditions are as follows:
Polishing belt particle size: # 100
Polishing belt rotation surface speed: 5 m / sec
Extruded product conveyance speed: 10 m / min
The molded body after the sanding treatment was visually evaluated for the wood texture, and the weather resistance was evaluated based on the appearance and color difference (ΔE) of a sunshine weatherometer after 2000 hours test.

Example 2
The two-layer molded product having a wood texture produced in Example 1 was printed on the surface of the sanding treatment using a brown weather-resistant paint so as to draw only the annual rings of the grain. Since the part between the annual rings is not coated with paint, the sanded surface appears on the surface as it is. Finally, a colorless weather-resistant clear paint was overcoated on the entire surface layer material.
The obtained molded body was evaluated in the same manner as in Example 1.

Example 3
A multilayer extruded product having a wood texture subjected to sanding treatment was produced in the same manner as in Example 1 except that the composition of the base material and the resin composition for the surface layer material was as follows.
Resin composition for base material-ABS resin containing 55% by weight of wood flour (foam)
Wood flour (average particle size 200μm) 55% by weight
ABS resin powder 32% by weight
AS resin powder 6% by weight
Magnesium stearate 3% by weight
Polyethylene wax 1% by weight
Effervescent agent (soda) 3% by weight
Resin composition for surface layer material-colored AAS resin (containing 5% by weight of talc)
To 100 parts by weight of AAS resin, 2 parts by weight of Bengala, 0.8 part by weight of titanium yellow, and 0.2 part by weight of carbon black were mixed and colored in the same color as wood. Further, talc was added so as to be 5% by weight in the total composition in order to enhance the wood texture when sanding.

Example 4
(1) Preparation of resin composition for base material and surface layer material
Substrate resin composition-ABS resin (foam)
A composition comprising the following resin components was made into pellets in the same manner as in Example 1.
ABS resin powder 80% by weight
AS resin powder 6% by weight
Magnesium stearate 3% by weight
Polyethylene wax 1% by weight
7% by weight of talc
Effervescent agent (soda) 3% by weight
Resin composition for surface layer material (mixed with colored PMMA)
A colored PMMA resin composition (base resin: MFR = 15 g / 10 min) prepared in the same manner as in Example 1 and the following seeds were prepared as pellets.
The seed was prepared by mixing 1 part by weight of Bengala and 1 part by weight of carbon black with 100 parts by weight of PMMA resin having an MFR of 0.8.
Each pellet of the base resin and the seed material was mixed to obtain a resin composition for a surface layer material.

(2) Extrusion molding of multilayer molded body As described above, as a surface layer material, a pellet mixture of 100 parts by weight of the base resin and 3 parts by weight of the seed material is put into a hopper of an extruder for surface layer material, and the resin composition for the base material A two-layer molded product was extruded together with the product.
(3) Sanding treatment and grain printing on the surface of the molded body The surface layer of the obtained extrusion molding was subjected to sanding treatment in the same manner as in Example 1 and further printed in grain as in Example 2.

Comparative Example 1
A non-foamed single-layer extruded product in which 55% by weight of the wood flour used in Example 1 was mixed with ABS resin was molded, and the surface was sanded by the same method and conditions as in Example 1.
Although the obtained molded body had a wood texture expressed by sanding, the result of the weather resistance test was not preferable because the wood powder inferior in weather resistance was exposed on the surface as it was.

Comparative Example 2
The two-layer extrusion molded product formed in Example 1 was directly subjected to a weather resistance test without being subjected to sanding or wood grain printing.
The result of the weather resistance test was good because this molded article covered the surface with PMMA resin having excellent weather resistance, but the surface appearance was glossy, far from the wood texture, and plastic-like. .

[Evaluation of extruded products]
About the molded object manufactured by the Example and the comparative example, wood texture and weather resistance were evaluated and the result was described in Table 1.
The weather resistance was evaluated by the accelerated test under the following conditions and the change in appearance and the color difference before and after the test.
The wood texture and appearance were determined by visual sensory evaluation.
Weather resistance test condition equipment: sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.)
Test conditions: Black panel temperature 63 ° C, with precipitation Accelerated test period: 2000 hours
Color difference measuring color difference meter: CM3600D (Minolta)
A color difference ΔE of 5 or less was evaluated as good weather resistance.

Sectional drawing which shows an example of the profile extrusion molding which consists of the surface layer material and base material of this invention.

Explanation of symbols

1: base material,
2: Surface layer material.

Claims (5)

From polymethyl methacrylate resin (PMMA resin), acrylonitrile / acrylic rubber / styrene copolymer resin (AAS resin), acrylonitrile / ethylene propylene rubber / styrene copolymer resin (AES resin) and methyl methacrylate / styrene copolymer resin (MS resin) The surface of the surface of the multilayer extrusion molded body comprising a transparent resin and a base material containing a filler and a colored resin obtained by coloring a resin excellent in weather resistance selected from the group is sanded. A multilayer extrusion molded body having a wood texture in which fine irregularities are formed and the surface is matte . A pattern made of the above seed resin in the surface layer material by extrusion molding a surface layer resin formed by mixing a base resin with a seed resin containing a colorant and having an MFR value lower than the MFR value of the surface layer base resin The multilayer extrusion-molded article according to claim 1, wherein is formed. The multilayer extruded body according to any one of claims 1 to 2, wherein the surface material surface is subjected to sanding treatment, printed with wood grain, and further subjected to clear coating. The multilayer extrusion molded article according to any one of claims 1 to 3, wherein the base material layer is a thermoplastic resin low foam extrusion moldable article. The multilayer extrusion molded article according to any one of claims 1 to 3, wherein the base material layer is a wood powder-containing thermoplastic resin molded article containing 5 to 85% by weight of wood powder or a low foam molded article thereof.

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