JP3885275B2 - Method for manufacturing metal plate-based melamine resin decorative board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a metal plate-based melamine resin decorative plate.
[0002]
[Prior art]
Metal plate-based melamine resin decorative plates are widely used as decorative materials for top plates of passenger train interior walls, tables, desks and the like.
The metal plate base melamine resin decorative board has a core layer made of a core material layer resin mainly composed of phenol resin and a paper base material (this paper base material is hereinafter referred to as core paper) on one side of the metal plate. Therefore, the surface layer is composed of a melamine resin and a paper base (this paper base is hereinafter referred to as decorative paper).
Specifically, resin impregnated core paper impregnated and dried with a core material layer resin and melamine resin impregnated decorative paper impregnated and dried with melamine resin are stacked in this order on a metal plate and molded by heating and pressing.
[0003]
The core material layer is between the surface layer and the metal plate and needs to act as a buffer material for both. For this reason, polyvinyl butyral modified phenolic resin obtained by modifying phenolic resin with polyvinyl butyral has been used as the core material layer resin in consideration of affinity with melamine resin and metal plate, action as a buffer material, and the like. .
[0004]
[Problems to be solved by the invention]
When the polyvinyl butyral modified phenolic resin is used as a varnish, there is an increase in viscosity due to polyvinyl butyral. When the viscosity of the varnish is high, the impregnation property is poor, and it is necessary to use a core paper having a small basis weight. For this reason, it is difficult to handle and the workability is deteriorated. Moreover, since the impregnation property is poor, voids are easily formed, resulting in poor heat resistance.
Therefore, an attempt has been made to use an epoxy-modified phenol resin obtained by modifying a phenol resin with an epoxy resin. The epoxy-modified phenolic resin has good impregnation properties and can be impregnated into a paper substrate having a large basis weight.
However, the good impregnation property leads to a large resin flow during molding. If the resin flow is large, the resin impregnated in the core paper during molding may move to the decorative paper on the surface. When the resin impregnated in the core paper is transferred to the decorative paper on the surface, the appearance is impaired.
[0005]
The purpose of the present invention is to prevent the resin impregnated in the core paper from shifting to the decorative paper in the manufacture of the metal plate-based melamine resin decorative board using a resin having a large resin flow during molding as the core material layer. To do.
[0006]
[Means for Solving the Problems]
The present invention relates to a metal plate characterized in that a metal plate, a resin-impregnated core paper, a paper base material impregnated and dried with a phenol resin adjusted to have a short curing time, and a melamine resin-impregnated decorative paper are stacked in this order and heated and pressed. It is a manufacturing method of a base melamine resin decorative board.
[0007]
Here, the curing time (also referred to as gel time) refers to injection of 0.5 ml of a resin sample into a dent of a hot plate heated to 160 ° C., and a needle having a tip diameter of about 0.15 mm is about 30 with respect to the horizontal plane. While maintaining the angle of the degree, it is the time until stirring until the sample loses its tackiness at a speed of 120 to 150 rpm.
[0008]
The phenolic resin impregnated and dried with a phenolic resin impregnated and dried with a short curing time (this paper substrate is hereinafter referred to as shielding paper) hardens early during molding, and the core layer resin flows. It works so as not to move to the surface layer side. For this reason, shortening the curing time means that the resin impregnated in the core paper is cured early enough to flow and cure before moving to the surface layer side.
[0009]
Moreover, in this invention, it is preferable to use the epoxy modified phenol resin with favorable impregnation property from a viewpoint of improving workability | operativity using a core paper with a large basic weight.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
As the metal plate as the base of the decorative plate in the present invention, an aluminum plate is preferably used in terms of light weight and resistance to corrosion, and an iron plate is used for applications that require special strength. Used. Although the thickness of a metal plate does not have a restriction | limiting in particular, Usually, it is the range of 0.8-1.2 mm, and is selected based on a specification etc.
The metal plate is preferably roughened on the decorative paper side by means such as sanding. Further, the adhesive layer may be formed by an adhesive such as phenol, chloroprene, or epoxy.
[0011]
As the core paper, kraft paper is preferably used from the viewpoint of price, and a paper having a basis weight in the range of 150 to 210 g / m ² is usually selected based on product specifications.
As core material layer resin, from the point of the adhesiveness with a metal plate and a surface layer, and the buffer action of a metal plate and a surface layer, from epoxy resin 10-30 weight part, and resol type phenol resin 90-70 weight part It is preferable to use an epoxy-modified phenol resin consisting of 15 to 25 parts by weight of an epoxy resin and 85 to 75 parts by weight of a resol-type phenol resin.
The core material layer resin is dissolved in a solvent and impregnated and dried as a varnish into the core material paper to obtain a resin-impregnated core paper. As the solvent, a general-purpose inexpensive solvent such as acetone or methyl ethyl ketone can be used.
The amount of the resin impregnated into the core paper is preferably 40 to 60% by weight, more preferably 45 to 55% by weight after drying from the viewpoint of leaving no voids and moldability. preferable. If the resin impregnation amount is less than 40% by weight, voids remain, and if it exceeds 60% by weight, the amount of resin flowing out during molding tends to increase.
[0012]
As the shielding paper, kraft paper can be used in the same manner as the core paper, but it is sufficient if the basis weight is sufficient to prevent the resin used for the core layer from transferring to the surface layer. Those having m ² are preferably used.
The curing time of the phenol resin impregnated in the shielding paper is preferably adjusted so that it is cured at the initial stage of molding. If the curing time is too short, the pot life after impregnating and drying the resin is shortened, and if the curing time is long, the effect of suppressing the transfer of the resin material used for the core material layer is lowered. Therefore, it is preferable that the curing time is adjusted to be 30 to 50 seconds.
The curing time of the phenolic resin can be adjusted by the amount of formaldehyde with respect to phenol and the conditions of vacuum concentration after reacting phenol and formaldehyde.
The obtained phenolic resin is dissolved in an appropriate solvent such as methanol and impregnated and dried as a varnish on the shielding paper to obtain a resin-impregnated shielding paper.
The amount of the resin impregnated into the shielding paper is preferably 40 to 60% by weight, more preferably 45 to 55% by weight after drying for the same reason as the core paper.
[0013]
As the decorative paper, a high-quality paper or a thin paper having a basis weight of 30 to 150 g / m ² printed with a plain or patterned pattern is used.
As the melamine resin impregnated in the decorative paper, plasticization obtained by reacting 1 mol of melamine in the range of 1.2 to 1.5 mol of formaldehyde and 0.1 to 0.2 mol of paratoluenesulfonamide. It is preferable to use a melamine resin.
Since the amount of aldehyde is reduced to reduce the crosslinking density, and the hardness of the melamine resin can be relaxed in combination with the addition of paratoluenesulfonamide in the crosslinked structure, cracks can be eliminated. is there. When the amount of formaldehyde with respect to 1 mol of melamine is less than 1.2 mol, the crosslinking density becomes too small, and when it exceeds 1.5 mol, the crosslinking density becomes too large. If the amount of paratoluene sulfonamide relative to 1 mol of melamine is less than 0.1 mol, the effect of plasticizing the melamine resin is small, and if it exceeds 0.2 mol, the hardness after curing becomes small and easily damaged.
The obtained melamine resin is dissolved in an appropriate solvent such as isobutanol to make a varnish, and impregnated and dried on decorative paper to obtain a melamine resin-impregnated decorative paper.
The amount of resin impregnation into the decorative paper is preferably 40 to 60% by weight, more preferably 45 to 55% by weight after drying for the same reason as that for the core paper.
[0014]
A metal plate, a resin-impregnated core paper, a resin-impregnated shielding paper, and a resin-impregnated decorative paper are stacked in this order and sandwiched between end plates, and heated and pressed to produce a metal plate-based decorative board. The conditions for heating and pressurization are selected in the range of, for example, a temperature of 80 to 180 ° C. and a pressure of 5 to 15 MPa according to a conventional method.
[0015]
【Example】
Example 1
100 parts of melamine (parts by weight, the same applies hereinafter) and 88 parts of a 38% by weight aqueous solution of formaldehyde were charged into a reaction kettle, and when the melamine became transparent, 20 parts of paratoluenesulfonamide (formaldehyde 1.4 mol per mol of melamine). Mole, 0.16 mol of p-toluenesulfonamide) was added and heated at 98 ° C. for 50 minutes to obtain a plasticized melamine resin. This plasticized melamine resin was dissolved in 30 parts of isobutanol to obtain a plasticized melamine resin varnish.
Using high-quality paper (basis weight 100 g / m ² ) printed with a pattern as decorative paper, the plasticized melamine resin varnish was impregnated while adjusting the impregnation amount after drying to be 50% by weight, at 100 ° C. The resin-impregnated decorative paper was obtained by drying for 3 minutes.
[0016]
70 parts of phenol, 220 parts of 38% by weight formaldehyde aqueous solution and 4 parts of ammonia are charged into a reaction kettle, heated at 92 ° C. for 90 minutes, and then concentrated under reduced pressure at 103 ° C. until the curing time reaches 40 seconds. Further, 105 parts of methanol was added to obtain a phenol resin varnish.
Using kraft paper (basis weight 80 g / m ² ) as the shielding paper, impregnating the phenolic resin varnish into the shielding paper while adjusting the impregnation amount after drying to 50% by weight, and drying at 130 ° C. for 3 minutes. Thus, a resin-impregnated shielding paper was obtained.
[0017]
An epoxy-modified phenolic resin varnish was prepared by dissolving 100 parts of an epoxy-modified phenolic resin (using No. 110 (trade name) manufactured by Cemedine Co., Ltd.) in 10 parts of acetone. In addition, said No. 110 is a weight ratio, which is composed of bisphenol A type epoxy resin 20 and resol type phenol resin 80, and has a curing time of 110 seconds.
Using kraft paper (basis weight 190 g / m ² ) as the core paper, impregnating the epoxy-modified phenolic resin varnish to the core paper while adjusting the resin adhesion after drying to 50% by weight, 110 Drying at 5 ° C. for 5 minutes gave a resin-impregnated core paper. The resin flow of the obtained resin-impregnated core paper was 10%.
Here, the resin flow refers to the weight of the sample before and after heating and pressurization after five samples cut into arbitrary dimensions are stacked, heated and pressurized at 140 ° C. and 10 MPa for 10 minutes, and then the resin protruding from the sample is scraped off. From the difference, the amount of resin protruding from the sample is obtained and expressed in%.
[0018]
An aluminum plate with a thickness of 1.2 mm (A3003P equivalent as defined in JIS H-4000), a resin-impregnated core paper, a resin-impregnated shielding paper, and a resin-impregnated decorative paper are stacked one by one in this order, and 30 ° C. and 10 MPa at 30 ° C. An aluminum plate-based melamine resin decorative plate was obtained by heating and pressing for a minute.
[0019]
The surface side of the obtained aluminum plate-based melamine resin decorative plate was visually observed, but it was beautiful and no abnormality was observed.
[0020]
Furthermore, for the obtained aluminum plate-based melamine resin decorative plate, JISK-6902 “Testing method of thermosetting resin decorative plate”, JIS K-6911 “General test method of thermosetting plastic”, former Japan National Railway Standard, JRS Tested in accordance with 17421-1. The test method and the results are as follows.
[0021]
Boiling resistance test (according to JlS K 6902 “Testing method for thermosetting resin decorative board”)
Three test pieces each having a size of 50 × 50 mm were prepared, and the cut surface was finished smoothly. This test piece was kept in a thermostat at 50 ± 3 ° C. for 24 hours, then immersed in boiling water for 2 hours, and the thickness and mass were measured before and after boiling. As a result, the thickness increase rate was 0.6% and the mass increase rate was 0.5%.
Further, the presence or absence of delamination was visually observed after immersion in boiling water for 2 hours and after immersion for 24 hours, but no separation was observed even after immersion for 24 hours.
[0022]
Surface scratch hardness (JIS K-6902): The surface side scratch hardness was measured using a Clemens type scratch hardness tester. As a result, the scratch hardness was 80 g.
[0023]
Heat resistance test (according to JlS K 6902 "Testing method for thermosetting resin decorative panel")
A test piece having a size of 230 × 230 mm was prepared, a flat bottom aluminum container filled with oil heated to 180 ° C. was placed on the surface side, and left for 20 minutes. The result was normal.
[0024]
Hot water resistance test (according to JlS K 6902 “Testing method for thermosetting resin decorative panel”)
One test piece having a size of 230 × 230 mm was prepared, boiling water was spilled on the surface side, a flat bottom aluminum container containing boiling water was placed on the test piece, and left for 20 minutes. The result was normal.
[0025]
Crack resistance test (former Japanese National Railway Standard, JRS 17421-1 compliant)
A test piece having a size of 100 × 100 mm was prepared, holes with a diameter of 5 mm were made in the four corners and the center, and the four corners were screwed to a steel jig plate having a thickness of 3.5 mm. This was kept in a constant temperature bath at 70 ° C. for 48 hours, then cooled to room temperature, and visually observed for cracks. As a result, no cracks were observed.
[0026]
Appearance test after heating (based on JlS K 6911 “General Test Method for Thermosetting Plastics”)
One test piece having a size of 50 × 50 mm was prepared, held in a thermostat bath at 180 ± 3 ° C. for 12 hours, and visually observed for significant changes such as cracks, blistering, and delamination. As a result, no cracks, blisters, or delamination were observed.
[0027]
【The invention's effect】
According to the present invention, even if a resin material having a large resin flow is used for the core layer, the core material paper having a large basis weight can be used without shifting to the surface layer, and the workability during production is good. Can be.

Claims (2)

A metal plate, a paper base material impregnated and dried with a core layer resin, a paper base material impregnated and dried with a phenol resin adjusted to have a short curing time, and a paper base material impregnated and dried with a melamine resin are stacked in this order and heated and pressurized. The manufacturing method of the metal plate base melamine resin decorative board characterized by these. The method for producing a metal plate-based melamine resin decorative plate according to claim 1, wherein the core layer resin is an epoxy-modified phenol resin.