JPS5849247A - Manufacture of natural grain decorative sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a natural wood decorative sheet, which aims to streamline and shorten the manufacturing process as well as improve and stabilize product quality.

Conventionally, when manufacturing natural wood decorative sheets, a solution of thermoplastic resin adhesive such as polyvinyl acetate is applied to a strong paper material such as kraft paper, and after drying, a thin sheet is formed. A method has been adopted in which a natural wood veneer cut into a shape is heat-pressed and then lined with kraft paper, polyethylene film, etc. on the back side, and then cured on a cooling stand. However, with this method, the manufacturing process is long, the productivity is extremely low, and there are considerable fluctuations in process conditions related to operations such as applying and drying the adhesive, making it difficult to produce products with stable quality. In addition to being difficult to obtain, when used for a long period of time, the surface of the natural wood veneer often develops "rack", and there are still many problems that need to be improved from a quality standpoint.

This invention was made with attention to the current situation, and is used as an adhesive base material for heat-compression bonding of thin veneers of cut natural wood. Japanese paper or non-woven fabric with a basis weight of 20-409 mm is fused and integrated with a 20-35 μm thick crystalline polyolefin resin film on paper with a weight of 50-1509 mm, and then a polyamide resin is applied on the surface of the Japanese paper or non-woven fabric. The present invention provides a method for producing a decorative natural wood sheet, which comprises melt-coating a hot melt adhesive containing as a main component to a thickness of 25 to 50 mm and using a T-adhesive base material. The details are described below.

This invention provides a base material to which a thin veneer of natural wood is attached.
There is a close relationship between the four-layer construction, the selection of the adhesive necessary for adhesion, and the method of applying it. In order to completely absorb the minute irregularities on the surface of the wood veneer and achieve satisfactory lamination adhesion, both are laminated with a layer with buffering capacity interposed therebetween. In other words, Tsubo ■ is 50 to 1509/d
Paper with a delamination strength of 3 to 9 or higher (for example, wet strength paper made using melamine resin or paper made using long fibers) is coated with a basis weight of 20~ 409 Shio Japanese paper or non-woven fabric, thickness 20~
They were integrated with a 35 μm crystalline polyolefin resin film by thermal welding, and exploded into a paper base material with buffering capacity. Here, the delamination strength of the base paper is 3Kykr4
The reason for this limitation is that if it is less than 3 to 9/crd, it is difficult to maintain the strength as a base material. The reason for setting 2.0 to 40 F/d is that anything below the respective lower limit values lacks strength, while anything exceeding the -F limit value may become unnecessarily heavy even if the strength is high.
This is because it becomes too thick, making it difficult to handle.

Next, the crystalline polyolefin resin used in this invention is high-density (medium-low pressure method) polyethylene, polypropylene, etc. The reason for choosing a crystalline polyolefin resin is that it has a relatively low melting point. in spite of,
This is because it has a large cohesive force, a high melt viscosity in the adhesive working temperature range (85 to 110°C), and can maintain sufficient heat resistance for practical use. Using such crystalline resin, you can make Japanese paper or non-woven fabric with a basis weight of 20 to 402 mm! i
Peel strength is 3KF/c+d or more and basis weight is 50 to 1s o
The crystalline resin is melt-bonded and integrated with the y/d paper, but the crystalline resin at this time may be melt-extruded or a film-formed resin may be hot-sealed, but in either case, the characteristics of the wood The width of the box should be 20 to 35μ. This is because, in order to fuse and integrate Japanese paper or nonwoven fabric with a basis weight of 20 to 409, this thickness range is sufficient to achieve the purpose.

Furthermore, the hot-melt adhesive to be melt-coated on the Japanese paper or non-woven fabric side H of the paper base material has creep resistance that can sufficiently withstand the expansion and contraction behavior of cut thin natural wood veneers in a dry and wet atmosphere, and wood Dimer is required to have an adhesion temperature range suitable for adhering products, as well as suitable heat creep resistance to maintain moisture resistance and heat resistance of the product. acid(
In other words, it is a polycondensate of a dibasic acid having 36 carbon atoms) and a diamine (e.g., ethylene diamine, hexamethylene diamine, etc.), and the main component is a polyamide resin having a melt viscosity of 60 to 400 poise at 180°C. The most suitable adhesive is a softening point measured by the ring and ball method of 85 to 120°C, and a creep temperature of 80 to 110°C when a 0.25 KS' shoulder shear force is applied.

Of course, the method for applying such a hot melt adhesive onto the Japanese paper or nonwoven fabric surface may be any method such as melt extrusion or thermocompression bonding of a film. Approximately 509/d is preferable. If it is less than 25g/y4, the adhesion of the natural wood veneer will not be sufficient, while if it is more than 509g/y4, it will often seep onto the surface of the natural wood veneer. This is because it will only lead to an increase in costs.

The natural wood veneer to be thermocompressed onto the Murakami adhesive prepared as described above is obtained by cutting thinly the wood that has been softened in very room temperature water and then drying it to a thickness of 0.15~ 0
．． 35 mm, and in order to heat-compress it by stacking it on the adhesive base material, the temperature is 85 to 110 °C and the pressure is 4 to 10 degrees.
/ctl for 10 to 60 seconds. After thermocompression bonding, the surface of the natural wood veneer is sanded and then painted to obtain a finished natural wood decorative sheet.

In this invention, the process of laminating paper and Japanese paper or non-woven fabric and spreading the hot melt adhesive both uses a hot melting method, so there is no residual residue caused by applying or drying the solution adhesive as in conventional methods. Problems such as moisture or residual solvents do not occur at all, and as a result, it greatly contributes to stabilizing production and quality. Furthermore, a thin natural wood tlIi board was heat-heated with a real-melt adhesive containing polyamide resin as its main component melted and applied.
Adhesive substrates that are not bonded with F have excellent storage stability. Therefore, by storing it as an intermediate product and overlaying it with desired natural wood 11t& when necessary and hot-pressing it, it is possible to quickly produce natural wood decorative sheets that meet demand. Therefore, even diversified customer requests can be adequately addressed with a production plan that has a considerable degree of freedom.

Examples are shown below.

[Example 1 of Example 1] Kraft paper with an interlayer peel strength of 4 to 9 yen and a basis weight of 752 mm, and washi paper (mixed paper with rayon fiber) with a basis weight of 282 mm.
are laminated using a 30μ thick high-density polyethylene film (melt extrusion method), and then on this Japanese paper, a polyamide resin obtained by polycondensation of dimer acid and hexamethylene diamine as the main component is layered. Hot melt adhesive (this adhesive has a melt viscosity of 150 poise at 180°C, a softening point of 98°C by the ring and ball method, and a temperature of 0.2 s K9/
CR! (with a creep temperature of 85°C when shearing force was applied) was melt-coated to a thickness of 369/d using a slit die.

An adhesive base material was prepared by integrating layers of kraft paper, polyethylene film, Japanese paper, and adhesive.

A decorative walnut veneer cut to a thickness of 0.3 m was further layered on this adhesive base material and heated at 95°C for 70 minutes using a heat press machine.
They were integrated by thermocompression bonding for 30 seconds using K9ki.

This decorative sheet was attached to an asbestos cement calcium silicate board, and the surface of the walnut veneer was sanded and finished with clear lacquer.

The decorative board obtained in this way was actually used as a building interior material for walls, doors, etc., but even after 24 months, no changes over time such as surface cracks were observed, and the interior was beautiful. It was showing effectiveness.

On the other hand, decorative boards obtained by conventional methods, such as applying a urethane resin flamer treatment to an asbestos cement calcium silicate board and directly bonding a walnut deck with a vinyl acetate adhesive, During the same period, discoloration of asbestos-cement calcium silicate plates caused by alkali, contamination, and cracking caused by deterioration over time were very clearly observed.

[Example 2] On the same adhesive base material as in Example 1, a thin veneer of teak wood with a thickness of 03 was heated to 926C18 and 9/c using a heat press machine.
A teak decorative sheet was produced by thermocompression bonding at R4 for 30 seconds. This decorative sheet was laminated to flame-retardant plywood which had been made flame-retardant by injecting polyphosphoric acid carbamate, the surface was sanded, and a clear lacquer finish was applied.

This flame-retardant decorative plywood has been used for architectural interiors (C) for 2 years and 4 years.
Observed during power. As a result, a decorative board made by directly bonding a natural wood veneer to a conventional flame-retardant apricot board using an amino adhesive,
The paint film peeled off due to moisture absorption of the flame retardant in the plywood, resulting in white staining, and contamination due to the flame retardant blowing out occurred with a probability of over 50%, but in the decorative sheet shown in this T example, No such change was observed at all.

rExample 3J A thin single phase of Moabi material with a thickness of 0.3 m was applied to the same adhesive base material as in Example 1 using a heat press machine at 90°C and 8 KF/c.
A Moavi decorative sheet was produced by thermocompression bonding at m for 30 seconds, and the surface was sanded and coated with clear lacquer. This decorative sheet was continuously attached to an asbestos cement calcium silicate board and a steel partition panel.

Conventionally, two materials have been used: one is a natural wood veneer directly bonded to an asbestos cement calcium silicate board, and the other is a conventional decorative sheet made by bonding a natural wood veneer to kraft paper using a vinyl acetate adhesive and bonded to a steel panel. Interior work has been carried out using a combination of these two materials, but between these two materials there are
The finish had a completely different texture, making it impossible to obtain a continuous appearance, and over a long period of time, discoloration staining and peeling of the veneer occurred. However, the decorative sheet obtained in this example showed continuity in material color and texture, giving it a sense of unity.
At t7, no changes over time were observed.

[Example 4] 25 pieces of bleached kraft paper with a delamination strength of 4.3 Ky/c7I and a basis weight of 702 mm, colored 1 piece pink, and 1 piece pink.
9/d rayon paper to a thickness of 30 μm using melt extrusion method.
The same polyamide resin hot melt adhesive used in Example 1 was applied onto the rayon paper using a slit die method to laminate it with a polypropylene film of 389/
An adhesive base material was prepared by melt coating and processing using the rd coating port.

On this base material, a cedar veneer with a thickness of 0.3 was heat-pressed using a heat press machine at 95° C. and 6 g for 30 seconds to produce a cedar veneer decorative sheet. This decorative sheet was adhered to gypsum board and installed on ceiling panels as a building interior.

Conventionally, directly adhering natural wood roots to gypsum board was extremely difficult to commercialize because the gypsum board base paper peeled during adhesion, but using the decorative sheet of this example This makes it easier to attach to the plasterboard, and it can be done without spoiling the aesthetics. Furthermore, the gypsum board to which the decorative sheet of this example was laminated could be bent along its wood edges, and the drawback of the conventional method, in which wood edges could not be pasted, could be overcome.

Patent applicant: Miyazaki Wood Industry Co., Ltd.
Sun Kasei Co., Ltd. Agent Kama 1) Bun 2

Claims (3)

[Claims] (1) As an adhesive base material for heat-compression bonding of cut natural wood thin plates, a sheet of paper with an interlayer peel strength of 3 to 9 l or more and a basis weight of 50 to 1509/i is used. /
The washi paper or non-woven fabric of A is integrated with a crystalline polyolefin resin film with a thickness of 20 to 35μ, and then a hot melt adhesive whose main component is polyamide resin is applied on the surface of the first-grade Japanese paper or non-woven fabric at a rate of 25 to 509/rr. A method H for producing a decorative natural wood sheet, characterized by using an adhesive base material melt-coated to a thickness of . (2) Cut natural wood thin veneer or 0.15~0
．． The method for producing a natural wood decorative sheet according to claim 1, which is a board having a thickness of 35 mm. (3) The method for producing a natural wood decorative sheet according to claim 1, wherein the polyamide resin is a resin obtained by polycondensation of dimer acid and diamine.