JP2002302653A - Method for bonding synthetic wood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for bonding a synthetic wood with the use of a polyolefin-based resin material which can obtain a sufficient adhesive strength even with a small adhesive area. SOLUTION: The method for bonding a synthetic wood obtained by uniformly mixing a polyolefin-based resin material with a natural cellulose based material comprises subjecting the surface of the above synthetic wood to be bonded to a surface roughing processing, then previously treating the surface to be bonded with a urethane-based primer, subsequently coating an adhesive having a storage modulus E' on curing of 5×10<8> to 1×10<12> (Pa) on the treated surface, and applying the coated surface to an adherend.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for bonding synthetic wood, and more particularly to a method for bonding synthetic wood obtained by mixing a polyolefin resin material and a natural cellulose material.

[0002]

2. Description of the Related Art A molded product obtained by adding a natural powder to a synthetic resin, kneading the mixture uniformly and molding the mixture is used as synthetic wood because it has a texture similar to that of natural wood.

In recent years, with increasing environmental awareness, higher safety is required for synthetic resins used for synthetic wood. Therefore, a method of manufacturing synthetic wood using a polyolefin resin material excellent in safety, for example, polyethylene or polypropylene, has been actively studied.

[0004] In addition, although the use of the synthetic wood has been developed at the same time, the technology required for utilizing a specific preferable bonding method or the like has not been known so far.
For example, Japanese Unexamined Patent Publication No. 9-286880 discloses that a wood powder containing a copolymer of ethylene and an α-olefin having a specific density and a specific melt index mixed with wood powder is used. Although a synthetic wood made of a resin composition is disclosed, no description is given of a bonding method when high bonding strength is required.

[0005] Further, in synthetic wood obtained by mixing a low-polarity polyolefin-based resin material such as polyethylene or polypropylene with a natural cellulose-based material as a polar material, adhesion itself is not easy. So far,
Synthetic wood made of polyolefin resin material is used for parts that do not require high adhesive strength, or it is adhered with a large adhesive area, and is attached using other fixing means such as metal screws. It was attached to the body.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a method for bonding synthetic wood using a polyolefin resin material, which can provide a sufficient bonding strength even with a small bonding area in view of the above-mentioned state of the art. Is to provide.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for bonding synthetic wood by uniformly mixing a polyolefin resin material and a natural cellulosic material. After roughening, the adhesive surface is preliminarily treated with a urethane primer, and then an adhesive having a storage elastic modulus E ′ of 5 × 10 ⁸ to 10 ¹² (Pa) upon curing is applied. It is characterized in that it is stuck to.

In a specific aspect of the present invention, an epoxy adhesive is used as the adhesive. Hereinafter, details of the present invention will be described.

The synthetic wood used in the present invention is obtained by uniformly mixing a polyolefin resin material and a natural cellulosic material by a conventionally known method and then molding it into a predetermined shape. It can be manufactured by a press, a press molding machine, a continuous extruder, an injection molding machine, or the like.

The polyolefin resin material in the synthetic wood to which the present invention is applied is not particularly limited.
Polyolefin-based resins obtained by copolymerizing an α-olefin monomer such as ethylene or propylene alone or copolymerized are widely used. For example, conventionally known polyethylene and polypropylene are preferably used. As the polyolefin resin material, only one kind may be used, or two or more kinds may be used in combination. The polyolefin-based resin material does not generate toxic gas when incinerated and discarded, is chemically stable, and can enhance the safety of synthetic wood.

However, within the range not to impair the object of the present invention, the α-olefin monomer is copolymerized with another monomer having a double bond or mixed with another polymer material which is homopolymerized. It may be something.

The above-mentioned natural cellulosic materials widely include crushed materials such as wood and bamboo, cutting powder, pulp, extracted fiber, rice hulls, walnut hulls and other cereal or fruit husks, and crushed materials thereof.

[0013] By adding and mixing a natural cellulosic material to a polyolefin-based resin material, a synthetic wood having an appearance, texture and smell similar to wood can be formed. However, the synthetic wood to which the present invention is applied may be a mixture of other synthetic organic materials and inorganic materials as long as the object of the present invention is not impaired.

The form of the above-mentioned natural cellulosic material in the synthetic wood to which the present invention is applied is not particularly limited, but it is desirable because the finely powdered natural cellulosic material is easily and uniformly mixed with the polyolefin resin material. A finely powdered natural cellulosic material having an average particle size of 10 to 100 μm is preferably used.

The mixing ratio of the polyolefin resin material and the natural cellulosic material in the synthetic wood to which the present invention is applied is not particularly limited, and a synthetic material containing these at an appropriate ratio depending on the purpose and application. Wood can be used. In addition, in synthetic wood obtained by mixing the polyolefin resin material and the natural cellulose material, the method of mixing these is also optional, and the present invention is applied to synthetic wood mixed and molded by various methods. I can do it.

In the bonding method of the present invention, the roughened surface of the synthetic wood is roughened, and the coated surface is treated with a urethane primer before the adhesive is applied. The use of the urethane-based primer increases the adhesive strength. Urethane-based primers adhere more strongly to natural cellulose-based materials than polyolefin-based resin materials.

Since urethane-based primers are generally high-polarity materials, they adhere more strongly to natural cellulose-based materials than to low-polarity polyolefin-based resin materials. The present inventors have found that, when bonding synthetic wood, it is possible to increase the bonding strength by using a primer that bonds to a highly polar natural cellulose-based material, rather than a polyolefin-based resin material. Was found to be suitable.

The reason why the primer which strongly adheres to the natural cellulosic material is preferable is that the primer is firmly adhered to the natural cellulosic material because the natural cellulosic material exists in a dispersed state in the polyolefin resin material. This is because bonding incorporating these as wedges is realized, and a large bonding strength is obtained.

Particularly preferred is a urethane-based primer of a type in which one or two or more liquids are blended at a predetermined ratio, and those containing an isocyanate group are used. This is because the isocyanate group reacts with the hydroxyl group of the natural cellulosic material, and the natural cellulosic material can be used as a stronger wedge.

Here, roughening the bonded surface of the synthetic wood means to partially remove the surface of the surface to be bonded by planing or sanding to provide irregularities such as grooves and holes. By this operation, the subsequently applied adhesive is cured, and then adheres to the irregularities on the surface of the synthetic wood, thereby achieving stronger adhesion by the so-called anchor effect.

The condition of the rough surface is that the maximum height _Ry of the rough surface after roughening the surface to be bonded of the synthetic wood is 40 to 40.
It is preferably 400 μm. If it is less than 40 μm, the effect of anchoring to the surface of the urethane-based primer or the adhesive is weak, and if the surface is roughened to a height exceeding 400 μm, the projections of the synthetic wood on the surface become weak, making it difficult to obtain sufficient strength. In addition, the cost of the surface processing and the adhesive increases. More preferably, it is 125 to 320 μm.

Here, the maximum height R of the surface roughness is
_y is a value specified in JIS B0601.

Further, since the polyolefin resin material has a higher fluidity at the time of mixing and heating than wood flour, the outermost surface of the synthetic wood contains more polyolefin resin material than the blended ratio. However, by roughening,
The surface rich in polyolefin resin is removed, and the amount of natural cellulosic material close to the blending ratio appears, and the above primers and adhesives can bond with more natural cellulosic materials than when no roughening is performed, resulting in strong adhesion Form.

In the case where pores are present between the polyolefin resin material and the natural cellulosic material on the surface after the roughening, the adhesive is more preferably cured after seeping into the pores. The pores are formed according to the material constituting the synthetic wood, the mixing conditions, or the operating conditions during roughening.

The form of the applied adhesive is not particularly limited, and various adhesives such as a solvent type, an aqueous type, a hot melt type, a one-part type or a two-part type reactive adhesive can be used.

The composition of the adhesive is not particularly limited. For example, an epoxy group-containing compound which is a reactant such as bisphenol A or epichlorohydrin and an amine compound having a functional group which reacts with the epoxy group, an acid anhydride compound, or phenol Epoxy resin adhesive by the reaction with an epoxy compound, isocyanate compound, polyamide compound, etc .; amino resin adhesive by the reaction of an amino group-containing compound such as urea, ethylene urea, melamine, benzoguanamine with formaldehyde; Phenolic resin adhesives by reaction with formaldehyde; thermosetting adhesives such as polyurethane-based resin adhesives by reaction of isocyanate group-containing compounds with hydroxyl group-containing compounds having functional groups that react with isocyanate groups and amino group-containing compounds. Good Like properly.

Among these, an epoxy resin adhesive is preferably selected from the viewpoints of adhesive strength, durability of the cured film, and the like. However, in the present invention, the storage elastic modulus E 'of the adhesive used must be in the range of 5 × 10 ⁸ to 1 × 10 ¹² . The storage elastic modulus was measured at a frequency of 10 Hz and a heating rate of 3 ° C./min with a shearing force applied thereto.
It is a value at ° C. Although the equipment for measuring the storage elastic modulus is not particularly limited, for example, VES-F-1 manufactured by Iwamoto Seisakusho
11 and the like.

In the present invention, by using an adhesive having the above storage elastic modulus range, an anchor effect on an adhesion surface of synthetic wood and an anchor effect on pores between a polyolefin resin material and a natural cellulose material can be obtained. Is further increased, and a high adhesive strength is obtained. When the storage modulus E ′ is 5 × 10 ⁸ (P
If it is less than a), the adhesive strength is not sufficiently increased because the adhesive film is easily broken. Further, the storage elastic modulus is 10
^If it exceeds ¹² (Pa), the adhesive film becomes too hard and brittle, and it is difficult to develop a sufficient adhesive strength.

As the adhesive having the above storage elastic modulus range, an epoxy adhesive is preferably used as described above. As such an epoxy adhesive, for example,
Konishi two-component epoxy polyamide adhesive,
Part number “E set”, Sanyo Kasei Kogyo Co., Ltd., two-pack reaction type epoxy phenolic adhesive, Sunmodule AD202 and the like.

The color of the adhesive used in the present invention is not particularly limited, and preferably has the same appearance as that of the synthetic wood to be bonded, and an adhesive having the same color as transparent or synthetic wood is preferably used. . In the present invention, the method for applying the adhesive is not particularly limited.

The bonding in the present invention is performed by applying an adhesive to the synthetic wood and then bonding the synthetic wood to the adherend. However, the other adherend is not particularly limited. In particular, when the adherend is also a synthetic wood, the present invention is suitably used. When the adherend is also made of synthetic wood, it is desirable that the synthetic wood on the adherend be treated with a urethane primer and applied with an adhesive according to the present invention.

After the adhesive is applied and bonded, it is preferable to remove excess adhesive that has protruded from the adhesive end face crossing the adhesive interface. If excess adhesive is present on the adhesive end face, the adhesive strength is not reduced, but the appearance is significantly impaired.

The removal of the excess adhesive may be carried out by wiping, or in the case of an adhesive in which a film is formed quickly, it may be removed by scraping. A method of reducing the amount of the applied adhesive may be considered in order to prevent excess adhesive from being generated on the bonded end face. However, if the applied amount of the adhesive is too small, sufficient adhesive strength cannot be obtained, which is not preferable.

A more preferable adhesive is one which permeates synthetic wood and exerts a stronger anchoring effect. In the case of such an adhesive, however, the excess adhesive which has protruded to the bonding end face is not suitable for the synthetic wood at the bonding end face. Sticking to the surface makes removal of excess adhesive cumbersome. Therefore, it is also preferable to place a mask around the bonding surface in advance. The means for forming the mask is not particularly limited. For example, a film or the like may be used, or a polymer solution which does not easily permeate synthetic wood may be applied and dried to form a mask.

When removing the excess adhesive, it is desirable that the surface of the synthetic wood be uniformly treated. To uniformly treat the surface is to modify the surface so that it has the same appearance as the other outer surface, such as scratches remaining after removing the excess adhesive on the end face and traces of adhesive soaked. This is done by file processing. In addition, when the adhesive is removed, the displacement may be corrected when the synthetic wood and the adherend are displaced during the bonding.

It is not always necessary to apply a coating to the synthetic wood after the bonding, but it is preferable because the coating improves the weather resistance and the like. In this case, the adhesion of the paint can be enhanced by the surface treatment after the adhesion.

The bonding method according to the present invention is generally used for bonding synthetic wood, and can be applied to obtain synthetic wood products of various shapes. It is preferably used.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by describing specific embodiments. In the following Examples and Comparative Examples, bonding was performed using the following synthetic wood.

As the polyolefin resin material, polyethylene (manufactured by Nippon Polychem Co., Ltd., trade name: Novatec PE)
100 parts by weight and wood flour as a natural cellulosic material (Watanabe Chemical Co., trade name: Cellulosin # 45) 30
0 parts by weight and 5 parts by weight of zinc stearate (trade name: SZ-2000, manufactured by Sakai Chemical Co., Ltd.) as a lubricant are uniformly kneaded with an extruder, and a width of 6 obtained by continuous molding.
A synthetic wood of 0 mm × length 200 mm × thickness 10 mm was obtained and cut out to prepare a synthetic wood test piece having a cross section of width 15 mm × thickness 10 mm and length 90 mm.

Example 1 Two test pieces obtained as described above were prepared, and one side of each test piece was roughened with a No. 80 sandpaper in a rectangular area of 15 mm × 15 mm as an adhesive area. Processed. When the maximum value _Ry of the surface roughness of the region subjected to the rough surface processing was measured, 220
μm. In this area, a two-component urethane-based primer (Capital Paint, aqueous primer A solution and B
Liquid A) and Liquid B are mixed in equal amounts to form about 0.02
g / one side.

After the primer was dried, about 0.2 g / one side of a two-part reaction type epoxy amide-based adhesive (E set, manufactured by Konishi Co., Ltd.) was applied to the bonding area. The test pieces were adhered to each other and adhered. At this time, the excess adhesive that had protruded from the adhesive end face was wiped off before the adhesive was cured.

After the bonded product obtained by laminating the two synthetic wood test pieces as described above is allowed to stand at 25 ° C. and 50% relative humidity for one week, the adhesive remaining on the bonded end surface remains. The material was removed with a cutter knife, and the surface of the bonded end face was treated with sandpaper No. 80 to obtain an adhesive test piece. Thus, the surface of the bonded end face was made uniform.

(Example 2) Adhesion and surface homogenization treatment were performed in the same manner as in Example 1 except that (Tosprim C, manufactured by GE Toshiba Silicone Co., Ltd.) was used as a urethane-based primer to obtain an adhesion test piece. Was. The end surface of the obtained adhesive test piece was uniform.

(Example 3) Adhesion and surface uniformity treatment were carried out in the same manner as in Example 1 except that a two-part reaction type epoxy phenol adhesive (manufactured by Sanyo Chemical Industries, Sun Module AD202) was used as the adhesive. Was carried out to obtain an adhesion test piece. The end surface of the obtained adhesive test piece was uniform.

(Example 4) Adhesion and surface uniformization were carried out in the same manner as in Example 2 except that a two-component reaction type epoxyphenol-based adhesive (manufactured by Sanyo Chemical Industries, Sun Module AD202) was used as the adhesive. Was carried out to obtain an adhesion test piece. The end surface of the obtained adhesive test piece was uniform.

(Example 5) Adhesion and surface uniformization were performed in the same manner as in Example 1 except that the surface of the 15 x 15 mm adhesion area was roughened with a No. 45 sandpaper. Obtained. The end surface of the obtained adhesive test piece was uniform. When the maximum value _Ry of the surface roughness of the bonding area was measured, it was 320 μm.

(Example 6) Adhesion and surface uniformization were performed in the same manner as in Example 3 except that the surface of the 15 x 15 mm adhesion area was roughened with a No. 45 sandpaper. Obtained. The end surface of the obtained adhesive test piece was uniform. When the maximum value _Ry of the surface roughness of the bonding area was measured, it was 320 μm.

(Comparative Example 1) Adhesion and surface uniformity treatment were carried out in the same manner as in Example 1 except that rough surface processing with sandpaper was not carried out to obtain an adhesion test piece. The end surface of the obtained adhesive test piece was uniform.

(Comparative Example 2) Adhesion and surface uniformity treatment were performed in the same manner as in Example 3 except that rough surface processing with sandpaper was not performed, and an adhesion test piece was obtained. The end surface of the obtained adhesive test piece was uniform.

Comparative Example 3 Example 1 was repeated except that a chloroprene-based adhesive (K17, manufactured by Konishi Co., Ltd.) was used as the adhesive.
Adhesion and surface uniformity treatment were performed in the same manner as described above to obtain an adhesion test piece. The end surface of the obtained adhesive test piece was uniform.

(Comparative Example 4) Adhesion and surface uniformization were performed in the same manner as in Example 1 except that an epoxy silicone adhesive (manufactured by Konishi, Bond MOS10) was used as the adhesive. Obtained. The end surface of the obtained adhesive test piece was uniform.

(Comparative Example 5) Silane-based primer (Tosprim D manufactured by GE Toshiba Silicone Co., Ltd.) as a primer
Was performed in the same manner as in Example 1 except for using, to obtain an adhesion test piece. The end surface of the obtained adhesive test piece was uniform.

(Comparative Example 6) Silane-based primer (Tosprim D, manufactured by GE Toshiba Silicone Co., Ltd.) as a primer
The adhesion and surface uniformization treatment was performed in the same manner as in Example 3 except for using, to obtain an adhesion test piece. The end surface of the obtained adhesive test piece was uniform.

(Comparative Example 7) Adhesion and surface uniformity treatment were performed in the same manner as in Example 1 except that a 15 × 15 mm adhesion area was roughened with a No. 800 sandpaper, and an adhesion test piece was obtained. Obtained. The end surface of the obtained adhesive test piece was uniform. When the maximum value _Ry of the surface roughness of the bonding area was measured, it was 25 μm.

(Comparative Example 8) Adhesion and surface uniformity treatment were performed in the same manner as in Example 3 except that a 15 × 15 mm adhesion area was roughened with a No. 800 sandpaper, and an adhesion test piece was obtained. Obtained. The end surface of the obtained adhesive test piece was uniform. When the maximum value _Ry of the surface roughness of the bonding area was measured, it was 25 μm.

(Evaluation of Examples and Comparative Examples) Examples 1-4
The normal state adhesive strength and the water-resistant adhesive strength of the adhesive products obtained in Comparative Examples 1 to 6 were measured in the following manner. The results are shown in Tables 1 and 2 below, together with the storage modulus E 'of the adhesive when cured.

Normal adhesive strength: 25 ° C. and relative humidity of 50
%, Using a tensile tester (Shimadzu Corporation, Autograph Machine), perform a tensile test at a distance between gripping jigs of 70 mm and a tensile speed of 3 mm / min. It was visually observed and evaluated.

Waterproof adhesive strength: 25 ° C. and relative humidity 50
%, The adhesive was immersed in water for one month, and after one month, the adhesive was taken out, excess water was wiped off, and 25 ° C
Under a condition of 50% relative humidity and a tensile tester (manufactured by Shimadzu Corporation, autograph machine), the distance between the gripping jigs was 70.
mm and a tensile speed of 3 mm / min, the adhesive strength was measured, and the form of fracture was visually evaluated.

The storage elastic modulus during curing E 'is a value obtained by measuring each cured adhesive by a method using VES-F-111 manufactured by Iwamoto Seisakusho as described above.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

According to the bonding method of the present invention, since the bonding surface of the synthetic wood is roughened first, irregularities are formed on the bonding surface, and the surface area on the bonding surface increases. Further, pores are formed between the polyolefin-based resin material and the natural cellulose-based material. Therefore, when treated with a urethane-based primer, the synthetic wood is coated by applying an adhesive after the urethane-based primer has firmly adhered to the highly polar natural cellulose-based material and treated with the urethane-based primer. Can be firmly adhered to the body. Further, when roughening the surface, by limiting the maximum height range of the surface to a specific range, the adhesion of the synthetic wood can be further strengthened.

Thus, according to the present invention, synthetic wood can be firmly bonded to each other or to an adherend other than synthetic wood, and the synthetic wood can be used for applications requiring high adhesive strength. And the synthetic wood can be firmly fixed to the adherend without requiring other fixing members such as metal screws.

Continuation of the front page F term (reference) 4J040 EB051 EB111 EB131 EC061 EF001 LA06 MA09 MA10 PA13 PA15

Claims (3)

[Claims] 1. A method for bonding synthetic wood obtained by uniformly mixing a polyolefin-based resin material and a natural cellulose-based material, wherein the surface to be bonded of the synthetic wood is roughened, and then the bonded surface is previously Perform treatment with urethane primer,
Next, the storage elastic modulus E ′ during curing is 5 × 10 ⁸ to 10 ¹² (P
A method for bonding synthetic wood, which comprises applying the adhesive of a) and bonding the same to an adherend. 2. The method for bonding synthetic wood according to claim 1, wherein the maximum height _Ry of the rough surface after roughening the surface to be bonded of the synthetic wood is 40 to 400 μm. 3. The method according to claim 1, wherein the adhesive is an epoxy adhesive.