JP3126951B2 - Woody resin structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a wood resin structure having a wood-like surface.

[0002]

2. Description of the Related Art Molded thermoplastic resins having a grain pattern are already commercially available and have a long history. However, it was far from tactile or visual woody feel.

[0003] In recent years, the development of materials having a woody texture, in which wood flour such as sawdust is combined with a thermoplastic resin, has been actively developed due to an increase in recycling tendency. However, these materials have drawbacks such as difficulty in bending and heavy weight.

[0004] In order to solve the above-mentioned drawbacks, there is a method of reducing the wall thickness and attaching MDF or wood as a backing material of a molded product. In this method, bending workability can be obtained by reducing the thickness, but an adhesive is required.
There is a disadvantage that the cost is increased due to the necessity of separate processing of DF and wood.

[0005] On the other hand, conventionally, a profile extruded product having an uneven thickness portion has a drawback that warpage tends to occur. For example, in the case of an L-shaped molded product having different thicknesses on each side, there is a drawback that the extruded product has a large warp because the molding shrinkage varies depending on the thickness.

[0006]

SUMMARY OF THE INVENTION The present invention not only has a visual appearance similar to wood, but also has a light weight, a tactile feel to wood, and has good bending workability and high screw pull-out strength. Still another object of the present invention is to provide a woody resin structure in which warpage hardly occurs even if it has an uneven thickness portion.

[0007]

The present inventor has made various studies to solve the above-mentioned problems. As a result, they have found that a woody resin structure having the following predetermined layers (A) and (B) can solve all of the above problems, and have completed the present invention.

That is, the present invention provides: (1) a woody resin structure comprising a core portion and a sheath portion surrounding the core portion, wherein the sheath portion is a cellulosic powder material 30 to 6;
A layer (A) comprising a resin composition containing 0 parts by weight and 70 to 40 parts by weight of a thermoplastic resin, wherein the core is a foamed layer (B) containing a thermoplastic resin, and the thickness of the layer (A) is It is a woody resin structure having a thickness of 10 mm or less and a thickness of the foamed layer (B) or less, and a foaming ratio of the foamed layer (B) of 1.2 to 5.0.

The inventor of the present invention firstly solves the disadvantages of a conventionally known material obtained by combining wood powder such as sawdust powder with a thermoplastic resin, that is, the disadvantages such as poor bending workability and heavy weight. To this end, a method was attempted in which a foaming agent was added to the material to foam the thermoplastic resin. However, the amount of wood flour is 20% by weight.
Above, the foaming gas escapes the gap between the wood flour and the resin, making it difficult to foam, or the flow of the coloring master batch for producing the wood grain pattern is disturbed, so that the sharpness of the grain pattern on the surface decreases A problem arose. On the other hand, if the amount of wood flour was small, foaming was relatively easy, but good woody touch was not obtained. Therefore, secondly, while maintaining the amount of cellulosic particles such as wood flour at a predetermined amount so as not to impair the woody feel of the material, it is lightweight, and has both good bending workability and high screw pull-out strength, Furthermore, the present inventors have studied to obtain a woody resin structure that does not warp. As a result, the thickness of the layer containing the cellulose-based powder (A) is set to the above-mentioned relatively small value, the reinforcing layer is made to be a foamed layer (B) having a predetermined expansion ratio, and the layer (A) and the foamed layer are Surprisingly, it has been found that when the thickness of (B) is maintained in a predetermined relationship, a woody resin structure having all the above characteristics can be obtained. Such a woody resin structure can be preferably formed by co-extrusion of the layer (A) and the foamed layer (B), so that separate processing of the adhesive and the reinforcing material is unnecessary, and the cost is also reduced. Very good.

In a preferred embodiment, (2) the woody resin structure according to the above (1), wherein the thickness of the layer (A) is 2 to 10 mm, and (3) the expansion ratio of the foamed layer (B) is 1.5. (4) any one of the above (1) to (3), wherein the thickness of the foamed layer (B) is 2 to 50 mm; ( 5 ) The above-mentioned (1) to ( 5 ), which are substantially columnar molded bodies.
( 4 ) The woody resin structure according to any one of ( 4 ), ( 6 ) the above (1), which is a molded body having an uneven thickness portion.
The woody resin structure according to any one of ( 1 ) to ( 5 ), ( 7 ) the molded body having the uneven thickness portion is a substantially L-shaped molded body having a layer (A) and a foamed layer (B), The layer (A) and / or the foam layer (B) forming each side have different thicknesses from each other, and the woody resin structure according to the above ( 6 ), ( 8 ) the above (1) formed by coextrusion. To woody resin structures described in any one of ( 7 ) to ( 7 ).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The cellulosic powder in the resin composition used in the layer (A) of the present invention is not particularly limited, and for example, sawdust, wood chips, pulp powder and the like can be used. Preferably, sawdust such as pine, cedar, cypress, hemlock and the like generated in the sawing process is used.

The thermoplastic resin used for the layer (A) is not particularly limited, but is preferably a polystyrene resin, an ABS resin, an AS resin, an AES resin, a modified PPE resin, a polycarbonate resin, a polymethyl methacrylate. Resins, polyacetal resins, polyethylene resins, polypropylene resins, polyamide resins, polyester resins, and the like. Particularly preferably, ABS resin,
Polystyrene resin, AS resin, AES resin, modified PPE
Resin and polypropylene resin are used. These thermoplastic resins may be used alone or in combination of two or more.

The blending amount of the cellulose-based particles and the thermoplastic resin in the resin composition used in the layer (A) is such that the amount of the thermoplastic resin is from 80 to 70 parts by weight of the cellulose-based particles.
30 parts by weight, preferably cellulosic powder 30-60
70 to 40 parts by weight of the thermoplastic resin with respect to parts by weight, particularly preferably 60 to 45 parts by weight of the thermoplastic resin with respect to 40 to 55 parts by weight of the cellulosic powder. If the cellulosic powder is less than the above lower limit and the thermoplastic resin is more than the above upper limit, the tactile sensation of wood is not obtained in the molded product, and the molded product having the uneven thickness portion is warped. If the amount of the cellulosic powder exceeds the above upper limit and the amount of the thermoplastic resin is below the above lower limit, granulation or the like becomes difficult, which hinders molding.

The above resin composition preferably contains a hydroxyl group (for example, 2-hydroxyethyl acrylate) or a carboxyl group (for example, 2-hydroxyethyl acrylate) in order to increase the compatibility between the cellulosic powder and the thermoplastic resin. A compound having a functional group such as methacrylic acid), an acid anhydride group, an epoxy group (for example, glycidyl methacrylate), an oxazolyl group, a maleimide group, an ester group, an amide group, and an ether group can be added.

The amount of these compatibilizers is preferably 1 part by weight, particularly preferably 3 parts by weight, and more preferably 3 parts by weight, based on 100 parts by weight of the total of the cellulosic powder and the thermoplastic resin. Is preferably 20 parts by weight, particularly preferably 10 parts by weight. If the amount is less than the lower limit, sufficient compatibility may not be obtained and the strength may be reduced. If the amount exceeds the upper limit, the effect is not increased and the cost is increased.

The resin composition used in the layer (A) of the present invention may contain various additives known to those skilled in the art, in addition to the above components, within a range not to impair the effects of the present invention. Add additives such as light stabilizers, antistatic agents, lubricants, dyes, pigments, plasticizers, mold release agents, glass fibers, metal fibers, metal flakes, flame retardants, ultraviolet absorbers, fillers, and reinforcing materials be able to.

As the thermoplastic resin used for the foamed layer (B) of the present invention, the same resin as the thermoplastic resin used for the layer (A) can be used. Preferably, the thermoplastic resin used for the foamed layer (B) and the thermoplastic resin used for the layer (A) may be of the same type in order to increase the adhesion between the resins. For example, polystyrene, A
For styrene resins such as BS resin, AS resin and AES resin, use a styrene resin, or a modified PPE resin such as a blend of PPE and styrene resin or a copolymer of styrene compound grafted on PPE. Is preferred. Further, it is preferable to use an olefin resin for an olefin resin such as a polyethylene resin and a polypropylene resin.

The upper limit of the expansion ratio of the foamed layer (B) is 5.
0, preferably 4.0, particularly preferably 3.0,
The lower limit is 1.2, preferably 1.5, particularly preferably 1.
7 When the expansion ratio is less than the above lower limit, bending is difficult, and the effect of weight reduction is low. If the upper limit is exceeded, the pull-out strength of the screw decreases, so that problems such as falling off when used as a structure occur.

As the foaming agent for obtaining the foamed layer (B), known substances can be used in known amounts. For example, a solid blowing agent such as sodium bicarbonate, ammonium carbonate, azodicarbonamide, benzenesulfonyl hydrazide and the like can be used.

The above-mentioned various additives can be added to the thermoplastic resin used for the foamed layer (B) as long as the foaming effect of the foaming agent is not impaired. It is also possible to include the above-mentioned cellulosic powder in less than 20 parts by weight. At this time, it is also possible to mix an appropriate amount of a compatibilizer in the same manner as described above.

The woody resin structure having the layer (A) and the foamed layer (B) of the present invention comprises a resin composition constituting the layer (A) containing a cellulosic powder and a thermoplastic resin, a foaming agent and It can be produced preferably by co-extrusion with a thermoplastic resin constituting the foamed layer (B) optionally containing various additives and the like. As a method of coextrusion, a known method can be used, and a foaming agent acts during extrusion molding to form a foamed layer (B).

The shape of the wooden resin structure having the layer (A) and the foamed layer (B) of the present invention thus produced is not particularly limited, and various shapes can be produced as desired. . Preferably, a substantially columnar shaped body in which the core portion is formed of the foamed layer (B) and the sheath portion is formed of the layer (A), and a square pillar-shaped formed body in which the layer (A) and the foamed layer (B) are superimposed. A molded body obtained by bending each of these molded bodies into a substantially L-shape or the like, or each of these molded bodies having an uneven thickness portion, for example, a substantially L-shaped body having a layer (A) and a foamed layer (B) Examples of the shaped body include a shaped body having a layer (A) forming each side and / or a foamed layer (B) having different thicknesses.

The layer (A) of the present invention and the foamed layer (B)
The thickness of the layer (A) is 10 mm or less, preferably 2 to 8 mm, and particularly preferably 4 to 6 mm.
It is. When the thickness exceeds the above upper limit, bending workability is deteriorated, and various problems such as occurrence of wrinkles in a molded product at the time of bending and a reduction in weight cannot be achieved. Further, the thickness of the layer (A) needs to be equal to or less than the thickness of the foamed layer (B). When the thickness exceeds the thickness of the foamed layer (B), the bending workability deteriorates. In particular, in the case of a cylindrical molded product, the bending workability further deteriorates. In addition, there also arises a problem that weight reduction cannot be achieved. The thickness of the foamed layer (B) is not particularly limited as long as it is equal to or greater than the thickness of the layer (A), but is usually about 2 to 50 mm. Here, each thickness of the layer (A) and the foamed layer (B) in the substantially cylindrical molded product is as follows:
The thickness of the layer (A) and the foamed layer (B) at the radius of the circle of the cross section of the molded article.

In the woody resin structure having the layer (A) and the foamed layer (B) of the present invention, the various effects of the present invention can be achieved. For example, layer (A)
The columnar hollow molded body having only a low bending strength has low bending strength and is easily broken. Further, a columnar molded body having only the layer (A) and having no hollow portion has high strength, but has poor bending workability.
It is heavy and has the drawback that nails and wood screws are difficult to strike.

In the woody resin structure of the present invention, the layer (A) and the foamed layer (B) are preferably colored in the same color. When the layer (A) and the foamed layer (B) are different in color tone or non-colored, it is not preferable because the cross section does not have a sense of unity and does not look like a tree.

The woody resin structure of the present invention is preferably used for building materials, automobile parts, decorative materials for home appliances, structural members and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0028]

【Example】

[0029]

Examples 1 to 4 and Comparative Examples 1 to 5 Components <Layer (A)> Resin composition containing cellulosic powder and thermoplastic resin: ABS resin Techno ABS400, trademark, manufactured by Techno Polymer Co., Ltd. Cellulose Saw powder generated in the lumbering process <Foam layer (B)> Thermoplastic resin: ABS resin CLALASTIC SXD220, trademark, manufactured by Sumika Avis Latex Co., Ltd. <Colorant>-Setsunan colored pellets 7AD0045 (trademark,
(Setsunan Chemical Co., Ltd.), about 5% by weight added to layer (A) Molding <Preparation of composition constituting layer (A)> Using ABS resin techno ABS400 and sawdust, cellulose-based powder and thermoplastic resin They were blended so that the content of the cellulosic powder in the resin composition containing the resin was a predetermined amount. 0.2 parts by weight of red iron oxide and 0.8 parts by weight of titanium yellow were added as coloring agents. Next, after mixing each component using a super mixer Z-1SP manufactured by Kawata Corporation, an extruded pellet was obtained using a twin screw extruder TEM-SS48 manufactured by Toshiba Machine Co., Ltd. <Preparation of composition constituting foam layer (B)> ABS resin
0.2 parts by weight of Bengala, 0.8 parts by weight of titanium yellow, and a predetermined amount of a foaming agent were added to the CLALASTIC SXD220 as colorants. Next, pellets were obtained in the same manner as described above. <Production of cylindrical rod-shaped molded article> The composition constituting the layer (A) and the composition constituting the foamed layer (B) produced as described above were separately supplied to separate single-screw extruders (FS50, trademark,
(Ikegai Co., Ltd., screw diameter 50 mm) and co-extruded simultaneously to obtain an outer diameter of 35 mmφ having the cross-sectional shape of FIG.
A cylindrical rod-shaped molded product having a two-layer structure was manufactured. At the time of extrusion, at the same time, setunan colored pellets as a coloring agent are added as a master batch to layer (A) to form layer (A).
A wood grain pattern was applied to the surface of.

Test <Bendability> A cylindrical rod-shaped molded product was cut into a length of 1.5 m. Both ends of the molded product were fixed, and hot air at 110 ° C. was blown to the center of the molded product for 10 minutes, and then the heated portion was gradually bent while blowing hot air. After bending, stop hot air,
The mixture was naturally cooled for 10 minutes as it was. Next, wrinkles and cracks in the bent portion were visually observed. Each symbol in Table 1 indicates the following.

○ No wrinkles or cracks × Wrinkles or cracks were significant <Pull-out strength of screw> A 3.45 mm hole was drilled in a cylindrical rod-shaped molded product, and a wood screw having an outer diameter of 4 mm was tightened. After fixing the molded product, the wood screw was pulled out, and the pull-out strength was measured. <Grain pattern> The grain pattern of the surface of the molded article was visually observed. Each symbol in Table 1 indicates the following. ○ Wood-like grain is recognized. × No grain is observed. <Tactile feel of wood> The surface of the molded product was touched by hand and evaluated by touch. Each symbol in Table 1 indicates the following.

○ Tactile sensation like wood is recognized. × Tactile sensation like plastic. The above results are shown in Table 1.

[0033]

[Table 1] Examples 1 to 3 are examples in which the content of the cellulose-based particles in the layer (A) is changed within the range of the present invention in the cylindrical rod-shaped woody resin structure of the present invention. Bending workability, grain pattern and feel of wood were all good. The pull-out strength of the screw was also good, and it was found that the strength increased remarkably when the content of the cellulosic powder was increased.
Example 4 differs from Example 1 in that the expansion ratio was increased within the scope of the present invention. Although the pull-out strength of the screw was somewhat low, the effect of the present invention could be sufficiently achieved.

On the other hand, in Comparative Example 1, the content of the cellulosic powder in the layer (A) was less than the range of the present invention.
The feel of the wood was noticeably worse and had a plastic feel. The pull-out strength of the screw was also significantly reduced. In Comparative Example 2, the content of the cellulosic powder was beyond the range of the present invention. Although the pull-out strength of the screw increases,
The bendability and grain pattern deteriorated markedly. Comparative Example 3
In Example 1, the thickness of the layer (A) was outside the range of the present invention. Although the pull-out strength of the screw increased, the bending workability deteriorated remarkably. In Comparative Example 4, the layer (B) of Example 1 was not used as a foam layer. Although the pull-out strength of the screw was high, the bending workability was remarkably deteriorated. Comparative Example 5 is different from Example 1 in that the expansion ratio of the layer (B) exceeded the range of the present invention. The pull-out strength of the screw was significantly reduced.

[0035]

Examples 5 to 8 and Comparative Examples 6 to 9 <Layer (A)> Resin composition containing cellulosic powder and thermoplastic resin: Polystyrene resin Denkastyrol GP-1, trademark, Denki Kagaku Kogyo Co., Ltd.・ Functional group-containing styrene resin Dailark 232, trademark, Nova Chemical Japan Limited (maleic acid-modified polystyrene) 5% by weight ・ Cellulose powder Granular material generated in sawmilling process <Foam layer (B)> Thermoplastic resin : ・ Polystyrene resin Denkastyrol QP-2, trademark, manufactured by Denki Kagaku Kogyo Co., Ltd. <Colorant>-Setsunan colored pellets 7AD0045 (trademark,
(Setsunan Chemical Co., Ltd.), about 5% by weight added to layer (A) Molding In the same manner as in the above example, an L-shaped extruded product having an uneven thickness portion having a cross-sectional shape as shown in FIG. Was manufactured.

Test <Warpage> The L-shaped molded product after the above extrusion molding was cut into a length of about 1 m, then left at room temperature for 1 hour, and the warpage was visually observed. Each symbol in Table 2 indicates the following.

○ No warpage × Large warp <Pull-out strength of screw> L-shaped molded product was drilled with 3.
A 45 mm hole was drilled, and a wood screw with an outer diameter of 4 mm was tightened [the foam layer (B) was tightened from the layer (A) side to the Zmm thickness portion]. After fixing the molded product, the wood screw was pulled out, and the pull-out strength was measured.

Table 2 shows the above results.

[0039]

[Table 2] In Examples 5 to 7, in the L-shaped woody resin structure of the present invention, the content of the cellulose powder in the layer (A) was changed within the range of the present invention. No warpage was observed in any of the molded products. The pull-out strength of the screw was also good, and it was found that the strength increased remarkably when the content of the cellulosic powder was increased. Example 8
In Example 5, the expansion ratio was increased within the scope of the present invention. Again, no warpage of the molded article was observed. Although the pull-out strength of the screw was somewhat low, the effect of the present invention could be sufficiently achieved.

On the other hand, in Comparative Example 6, the content of the cellulose powder in the layer (A) was less than the range of the present invention. A large warpage was observed in the molded product. Comparative Example 7 is different from Example 5 in that the thickness of the layer (A) is out of the range of the present invention. The molded product was significantly warped. In Comparative Example 8, the layer (B) of Example 5 was not used as a foam layer. Again, significant warpage was observed in the molded article. Comparative Example 9 is different from Example 5 in that the expansion ratio of the layer (B) exceeded the range of the present invention. No warpage was observed, but the pull-out strength of the screw was extremely low.

[0041]

The present invention not only has an appearance similar to wood visually, but also has a light weight and a tactile feel of wood, and has both good bending workability and high screw pull-out strength. Provided is a woody resin structure in which a warp hardly occurs even if it has a meat portion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a wooden resin structure of the present invention having a cylindrical rod shape having a two-layer structure.

FIG. 2 is a sectional view of an L-shaped woody resin structure of the present invention having an uneven thickness portion.

[Explanation of symbols]

A: Layer (A) composed of a resin composition containing a cellulose-based powder and a thermoplastic resin B: Foamed layer (B) X: Thickness of layer (A) Y, Z: Thickness of foamed layer (B)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B29K 105: 04 B29L 9:00 (72) Inventor Hiromichi Uohashi 3-4-10 Hatchobori, Chuo-ku, Tokyo Inside Ecopolmer Co., Ltd. (72 ) Inventor Kenichi Senba, 335-1 Higashi-Tanaka, Gotemba-shi, Shizuoka Prefecture (72) Inventor Takahiko Nagata 335-1, Higashi-Tanaka, Gotemba-shi, Shizuoka Prefecture (56) References JP-A-6-330558 (JP, A) JP-A-9-11386 (JP, A) JP-A-11-138703 (JP, A) JP-A-11-34148 (JP, A) JP-A 8-207111 (JP, A) JP-A-6-75738 (JP) , U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 47/00-47/96

Claims (4)

(57) [Claims] 1. A wood resin structure comprising a core and a sheath surrounding the core, wherein the sheath is a cellulosic powder or granular material.
A layer (A) made of a resin composition containing 30 to 60 parts by weight and 70 to 40 parts by weight of a thermoplastic resin, wherein the core is a foamed layer (B) containing a thermoplastic resin; The thickness is not more than 10 mm and not more than the thickness of the foamed layer (B).
A woody resin structure in which the expansion ratio of the foamed layer (B) is 1.2 to 5.0. 2. The woody resin structure according to claim 1, which is a substantially columnar molded body. 3. The woody resin structure according to claim 1, wherein the woody resin structure is a molded body having an uneven thickness portion. 4. The woody resin structure according to claim 1, which is formed by coextrusion.