JP2003082311A - Hot melt adhesive composition for bonding wood, and woodgrain decorative board and woodgrain decorative sheet obtained using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot melt adhesive composition exhibiting not only good adhesive properties but also excellent water resistance and excellent boiling resistance when used for bonding a woody material to various plastic materials or to another woody material, and to obtain a woodgrain decorative board and a woodgrain decorative sheet which meet the JAS standard (for special plywood type 1) using the adhesive composition. SOLUTION: The hot melt adhesive composition for bonding wood comprises (a) 10-85 wt.% of a saponified product of an ethylene/vinyl acetate copolymer having a saponification ratio of at least 30% and (b) 15-90 wt.% of an ethylene/ acrylic acid compound copolymer, where the MFR of the composition is 1-50 g/10 min. The woodgrain decorative board and the woodgrain decorative sheet are obtained using the hot melt adhesive composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-melt adhesive composition for wood adhesion, which is suitable for adhesion of wood and has improved water resistance and boiling resistance, and a wood decorative board or wood decorative sheet using the same. Regarding

[0002]

2. Description of the Related Art Recently, in the field where natural wood has been used, plywood, particle board, and MDF (Medium Densit) have been used for the purpose of effectively utilizing wood.
y Fiber boards: medium-quality fiberboard) or processed wood (substrate) such as laminated wood is widely used.

Usually, in order to further increase the commercial value of these substrates, for example, a wood decorative sheet or a wood decorative board in which a substrate is attached to a thin natural wood plate called a veneer is manufactured.
Then, in order to protect the surfaces of the wood decorative board and the wood decorative sheet and maintain the aesthetic appearance, a synthetic resin film is attached to the surface of the veneer.

V which is the cause of sick house syndrome
OCs (Volatile organic comp
Due to problems such as outs) gas, environmentally friendly synthetic resin films and adhesives used for producing wood decorative boards and wood decorative sheets are required.

The hot-melt adhesive is an adhesive composed of a thermoplastic resin that melts by heating, is applied to the surface of the adherend, and then is cooled to develop the adhesive function between the adherends. Since it is excellent in workability and economy and is solvent-free, it does not generate VOCs gas.

As a hot melt adhesive, ethylene
Adhesive composition comprising vinyl acetate copolymer, tackifying resin and wax (JP-A-4-173889), adhesive composition comprising polymer of ethylene and α-olefin and tackifying resin (JP2000 No. 17243), a resin composite film-coated wood decorative material with improved adhesive strength using a hot melt adhesive composed of a thermoplastic resin and a tackifier (JP-A-11-70505), ethylene / acrylic acid copolymer Alternatively, a flexible printed circuit board using a hot melt resin composed of an ethylene / methacrylic acid copolymer and an ethylene / vinyl acetate copolymer (Japanese Patent Laid-Open No. 61-110)
No. 546) is disclosed. When these known hot melt adhesive compositions are used for the production of wood decorative boards and wood decorative sheets, the adhesive strength and room temperature water resistance, boiling resistance in the adhesion of wood and plastic materials such as veneer and synthetic resin film. None of them satisfy all of the performance, and further improvement is required.

Further, as a hot-melt adhesive used for producing a decorative board and a decorative sheet, a hot-melt adhesive composition comprising a saponified ethylene-vinyl acetate copolymer and polyamide (Japanese Patent Publication No. 62-9274). Japanese Laid-Open Patent Publication No. 9-164651 and Japanese Laid-Open Patent Publication No. 9-164651) are known, but these do not have sufficient water resistance and boiling resistance in bonding wood and plastic materials. Further, since the composition has tackiness, it is difficult to handle an adhesive processed into a film. On the other hand, as an adhesive having good water resistance, there is a moisture-curable polyurethane-based hot melt adhesive (Japanese Patent Laid-Open No. 10-500715), but the adhesive is hardened by moisture in the air. Therefore, it is difficult to handle and the adhesive layer after curing is too hard. As a hot-melt adhesive for wood adhesion suitable for wood decorative boards and wood decorative sheets, the adhesive strength and room temperature water resistance in both wood such as veneer and substrate and wood and plastic material such as synthetic resin film. What is required to satisfy all of the boiling resistance is required.

[0008]

DISCLOSURE OF THE INVENTION An object of the present invention is to bond wood, which has good adhesiveness, water resistance and boiling resistance suitable for the production of wood decorative boards and wood decorative sheets and is easy to handle. It is intended to provide a hot-melt adhesive composition, and a wood decorative board and a wood decorative sheet adhered by using the adhesive composition.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a saponification product of an ethylene / vinyl acetate copolymer having a saponification rate of 30% or more may be used as a copolymer of ethylene and acrylic acid. When the composition containing the polymer has specific physical properties, it improves the water resistance at room temperature in the adhesion between the wood and the plastic material such as the veneer and the synthetic resin film without impairing the adhesion performance between the wood such as the veneer and the substrate. It was found that the boiling resistance was improved, and the present invention was completed. That is, (a) the saponification rate is 3
Saponified ethylene / vinyl acetate copolymer having a content of 0% or more;
10 to 85% by weight (b) a copolymer of ethylene and acrylic acid; a composition containing 15 to 90% by weight, wherein the MFR of the composition is 1 to 50 g / 10 minutes. A hot-melt adhesive composition for adhering wood, and a wood decorative board and a wood decorative sheet bonded by using the adhesive composition.

The present invention will be described in more detail below. As the (a) saponified product of ethylene / vinyl acetate copolymer used in the present invention, a commercially available ethylene / vinyl acetate copolymer is used. Preferably, an ethylene / vinyl acetate copolymer having a vinyl acetate content of 20 to 70% by weight is saponified by a known method. The saponification product of the ethylene / vinyl acetate copolymer used in the present invention has a saponification rate of 30% or more, more preferably 40 to 80%. If the saponification rate is lower than 30%, the water resistance will decrease.

The MFR of the saponified ethylene / vinyl acetate copolymer (a) used in the present invention is not particularly limited, but it is 1 to 50 g / 10 minutes (190 ° C., 2160 g load,
JIS K7210) is a preferred range. MFR is 1
If it is less than g / 10 minutes, the melt viscosity of the composition becomes too high, which hinders the melt coating of the adhesive and the molding of the film adhesive. On the contrary, if the MFR is more than 50 g / 10 minutes, the adhesive strength of Cause a decline.

Specific examples of the (a) saponified product of the ethylene / vinyl acetate copolymer used in the present invention include Technolink DR-55, DR-150, R-100 manufactured by Taoka Chemical Co., Ltd.
R-400, K-400, K-431, Tohso's Mersen H-6051, H-6820, H-6822X, Takeda Pharmaceutical's Dumiran D-219, C-2280, C-1.
550, E-222 and the like.

The saponified ethylene / vinyl acetate copolymer (a) used in the present invention may be used alone or in combination of two or more.

The (b) copolymer of ethylene and acrylic acid used in the present invention is preferably a commercially available product. The content of acrylic acid in the copolymer is 1 to 25% by weight, and 5 to 25% by weight is used.
Is more preferable. If the content of acrylic acid is more than 25% by weight, the water resistance is lowered, and if it is less than 1%, the adhesive strength is lowered. The MFR of the component (b) is not particularly limited, but it is 1 to 50 g / 10 minutes (190 ° C, 2160 g).
Load, JIS K7210) is a preferable range. M
If the FR is less than 1 g / 10 min, the melt viscosity of the composition becomes too high, which hinders the application of adhesive and the molding into a film. On the contrary, if the MFR is more than 50 g / 10 min, the adhesive strength decreases. Cause

Specific examples of the copolymer (b) used in the present invention include ethylene / methacrylic acid copolymers.
Nukurel AN421 manufactured by Mitsui DuPont Polychemicals
4C, Nukurel N1035, Nukurel N121
4, Nukurel N1525, Nukurel N1207
C, N903HC, and the like. Examples of ethylene / acrylic acid copolymers include Nucrel AN4221C and Nucrel AN4225C manufactured by Mitsui-DuPont Polychemical Co., Ltd.
Nucrel N5130H and the like can be mentioned.

The above-mentioned copolymer of ethylene and acrylic acid may be used alone or in combination of two or more kinds.

The blending ratio of the hot-melt adhesive composition for adhering wood according to the present invention is as follows: (a) 10 to 85% by weight of saponified ethylene vinyl acetate copolymer having a saponification rate of 30% or more, (b) 15 to 15 ethylene-acrylic acid copolymers
90% by weight, and a more preferable blending ratio is (a) 25 to 75% by weight of saponified ethylene / vinyl acetate copolymer,
(B) 25 to 75 copolymers of ethylene and acrylic acid
%, More preferably 25 to 70% by weight of the saponified ethylene / vinyl acetate copolymer (a),
(B) The copolymer of ethylene and acrylic acid is 30 to 75
% By weight. If the content of the saponified product of the ethylene-vinyl acetate copolymer having a saponification rate of 30% or more is lower than 10% by weight or higher than 85% by weight, the water resistance is lowered.

In the hot-melt adhesive composition for adhering wood of the present invention, if necessary, other thermoplastic resin, rubber, plasticizer, filler, lubricant, anti-blocking agent,
Stabilizers such as antioxidants can be appropriately added.

Specific examples of the thermoplastic resin include ethylene / vinyl acetate copolymer, polymethylmethacrylate,
Examples thereof include styrene-based thermoplastic elastomer, polyvinyl chloride, polyester, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyvinyl ether, polyurethane and the like.

Specific examples of the rubber include styrene-butadiene rubber, natural rubber, isoprene rubber, butyl rubber,
Examples thereof include polystyrene-polybutadiene block copolymers and polystyrene-polyisoprene copolymers.

The MFR of the hot-melt adhesive composition for adhering wood according to the present invention is 1 to 50 g / 10 minutes (190 ° C., 21
A load of 60 g, JIS K7210) is used. If the MFR is less than 1 g / 10 minutes, the melt viscosity of the composition will be too high, which will hinder the application of adhesive and the formation into a film. Conversely, if the MFR is more than 50 g / 10 minutes, the adhesive strength will decrease. Cause

As a method for producing the hot-melt adhesive composition for bonding wood according to the present invention, a known melt-kneading method using a roll, a Banbury kneader, a uniaxial kneader, a biaxial kneader, a kneader or the like can be applied. The melt-kneading is preferably carried out under the condition that gelation of the compound does not occur, and although it varies depending on the kneading machine, usually, kneading at a temperature of 60 to 300 ° C. for a time of 30 seconds to 30 minutes is preferable.

The method for applying the hot-melt adhesive composition for adhering wood according to the present invention can be applied in various forms, and can be most preferably used as a film-like adhesive. The adhesive film of the hot melt adhesive composition of the present invention has T
A die film-forming machine or an inflation film-forming machine can be used to form a film in the same manner as ordinary plastics.

The grain decorative sheet of the present invention can be produced by a known method such as bonding a synthetic resin film and a veneer by hot pressing using the hot melt adhesive composition of the present invention. At this time, the hot-melt adhesive composition for wood adhesion according to the present invention, which has been formed into a film, may be previously subjected to extrusion laminating treatment on a synthetic resin film.

The wood decorative board of the present invention is a wood decorative sheet produced by a known method such as bonding a synthetic resin film and a veneer by hot pressing using the hot melt adhesive composition of the present invention. In the method for bonding a substrate with the hot-melt adhesive composition for wood adhesion of the present invention or another adhesive, or with a hot-melt adhesive composition for wood adhesion of the present invention or a veneer and a substrate with another adhesive It can be produced by a known method such as pre-adhesion and adhering it to the synthetic resin film by hot pressing using the hot melt adhesive composition of the present invention. At this time, the hot-melt adhesive composition for wood adhesion according to the present invention, which has been formed into a film, may be extruded and laminated on a synthetic resin film in advance.

[0026]

EXAMPLES The present invention will be described below with reference to examples. With respect to Examples 1 to 10 and Comparative Examples 1 to 6, hot melt adhesive compositions having the compositions shown in Tables 1 to 5 were blended, and MFR measurement and adhesiveness evaluation were performed by the methods described below.

<MFR measurement> MFR in accordance with JISK-7210 (flow test method for thermoplastics)
Was measured.

As the adherend and the adhesive, those shown below were used. <Plywood> JAS1 type China plywood (4 × 25 × 50 mm) manufactured by Nippon Test Panel Osaka Co., Ltd. was used after being heated or dried at room temperature to remove water adhering to the surface. <PP sheet> Shin-Kobe Electric PP sheet (PPN-AN
The thickness of 300 μm) was surface-treated with a corona surface treatment device (Kasuga Denki's output: 0.65 kW, running speed: 10 m / min) and used as it was. <Adhesive Film> The above adhesive composition was molded into a film having a thickness of about 300 μm at a temperature of 150 ° C. using a press molding machine and used for an adhesion test.

The tackiness test of the adhesive film was carried out and evaluated under the following conditions. Examples 1 to 1 in Tables 1 to 3
The hot melt adhesive composition was blended in the composition shown in 10 and the thickness was about 300 at a temperature of 150 ° C. using a press molding machine.
After stacking five adhesive films obtained by molding to a thickness of μm, applying a load of 1 Kg / 0.01 m ² and storing for 5 days under the condition of 10 ° C. to 50 ° C. The agent film was easily peeled off and it was confirmed that there was no tackiness.

The evaluation of adhesiveness was carried out under the following conditions. <Normal adhesive strength (peel)> An adhesive film was sandwiched between a PP sheet and plywood, adhered at 110 ° C. × 0.1 MPa / cm ² × 30 seconds, cooled to room temperature, and then 180 ° peel strength was measured. . <Normal adhesive strength (shear)> Adhesive film is sandwiched between plywood, bonded area: 1.0 x 2.5 cm, bonded at 150 ° C x clip pressure x 15 minutes, cooled to room temperature, then decompressed and pulled Shear bond strength was measured. <Boiling adhesive strength (shear)> Bonding in the same manner as in the normal adhesion test (shear), immersing in boiling water for 4 hours, cooling in normal temperature water for 1 h or longer, and pull shear adhesive strength as it is without draining water Was measured. <Water resistant adhesive strength (shearing, 25 ° C for 1 month)> Bonding in the same manner as in the normal adhesion test (shearing), immersing in normal temperature (25 ° C) water for 1 month, and then pulling shear adhesive strength as it is without draining water. Was measured. <JAS (special plywood type 1) test> An adhesive film is sandwiched between a PP sheet and plywood, 110 ° C. × 0.1 MPa / cm ²
Adhesion in × 30 seconds, cool to room temperature, then Japanese agricultural standards
(JAS; special plywood) The test was carried out according to the test method, and the pass / fail judgment was made.

[0031]

[Table 1] Table 1 1) Material rupture K-431: Saponified ethylene / vinyl acetate copolymer; Taoka Chemical Co., Ltd. (Technolink K-431) N1525: Ethylene / methacrylic acid copolymer; Mitsui
DuPont Polychemical (Nucrel N1525) N1207C: Ethylene / methacrylic acid copolymer; Mitsui / DuPont Polychemical (Nucrel N1207C) N0903HC: Ethylene / methacrylic acid copolymer; Mitsui / Dupont Polychemical (Nukurel N0903)
HC)

[0032]

[Table 2] Table 2 1) Material fracture

[0033]

[Table 3] Table 3 K-131: Saponified ethylene / vinyl acetate copolymer; manufactured by Taoka Chemical Industry (Technolink K-131) R-100: Saponified ethylene / vinyl acetate copolymer; manufactured by Taoka Chemical Industry (Technolink R-100) R-400: Saponified ethylene / vinyl acetate copolymer; manufactured by Taoka Chemical Co., Ltd. (Technolink R-400) AN4225C: ethylene / acrylic acid copolymer; manufactured by Mitsui / Dupont Polychemical (Nukurel AN4225)
C)

[0034]

[Table 4] Table 4 DR-150: Saponified ethylene / vinyl acetate copolymer;
Taoka Chemical Industry (Technolink DR-150) N1050H: Ethylene / methacrylic acid copolymer; Mitsui / DuPont Polychemical (Nucrel N1050H)

[0035]

[Table 5] Table 5 K-400: Saponified ethylene / vinyl acetate copolymer; Taoka Chemical Co., Ltd. (Technolink K-400) 6239: Polyamide; Henkel (Macromelt 6239) KA-31: Ethylene / vinyl acetate copolymer; Sumitomo Chemical Industry (Sumitate KA-31) N1050H: Ethylene / methacrylic acid copolymer; Mitsui / DuPont Polychemical (Nukurel N1050H)

[0036]

EFFECTS OF THE INVENTION According to the present invention, there is provided a hot melt adhesive composition having good adhesiveness, excellent water resistance and boiling resistance when a wooden material is bonded to various plastic materials and wooden materials. By using the adhesive composition, a wood decorative board and a wood decorative sheet that pass the JAS (special plywood type 1) standard can be obtained.
Further, the adhesive film made of the hot melt adhesive composition of the present invention has no tackiness on the surface and is easy to handle.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 131/04 C09J 131/04 133/02 133/02 (72) Inventor Wakatsuki Tsuki 4 Mitsukuni Nishi, Yodogawa-ku, Osaka chome No. 2 11 Gota bonito chemical industry Co., Ltd. in the F-term (reference) 2B002 AA02 AA03 BA01 BB07 2B200 AA01 BA01 BA15 CA11 EA06 EE13 EF11 FA24 FA31 HA05 2B250 BA06 CA11 DA04 EA02 EA13 FA21 FA28 FA31 FA37 4F100 AK69G AK71G AL05G AP00A AP00B BA02 CB00 JA06G JB06 JJ03 YY00G 4J040 DA051 DB042 DD022 DD031 DD052 DE031 DF011 DF052 DM012 GA05 GA07 JB01 LA01 LA07 LA08 MA08 NA05 NA12

Claims (3)

[Claims] 1. A saponification product of (a) an ethylene / vinyl acetate copolymer having a saponification rate of 30% or more; 10 to 85% by weight,
(B) Copolymer of ethylene and acrylic acid; 15 to 90
A composition containing 10% by weight, the MFR of the composition
Is 1 to 50 g / 10 minutes, a hot-melt adhesive composition for bonding wood. 2. The hot-melt adhesive composition for adhering wood according to claim 1, wherein the content of acrylic acid in the copolymer of ethylene and acrylic acid is 1 to 25% by weight. 3. A wood decorative board or wood decorative sheet comprising the hot-melt adhesive composition for bonding wood according to claim 1 or 2.