JP4337480B2 - Decorative sheet - Google Patents

Description

  The present invention is a cosmetic material bonded to the surface of various base materials for decorative materials such as a wooden base material, an inorganic base material, a synthetic resin base material, and a metal base material. It relates to a decorative sheet for use in building materials such as exterior materials and fittings, exterior materials such as furniture, furniture, housing equipment, and home appliances, and interior and exterior materials in transportation equipment such as automobiles. The present invention relates to a decorative sheet having excellent hardness and impact resistance against falling balls.

  In general, a decorative sheet is required to have excellent surface hardness, wear resistance, and scratch resistance so that it can be used for many years as a surface decorative material such as a house interior material. Since materials such as paper and synthetic resin film normally used as a base material for decorative sheets are not necessarily sufficient in terms of physical properties such as surface hardness, thermosetting resins and ionizing radiation curable resins are formed on the surface. In many cases, a hard protective layer made of, for example, is provided as the outermost layer.

In order to increase the surface hardness of the decorative sheet, the hardness of the resin used for the protective layer may be increased. However, a resin with high hardness has a high curing shrinkage due to a high crosslinking density in the curing reaction, and is liable to cause poor adhesion to the substrate due to the shrinkage stress associated therewith. Further, since the resin is difficult to deform and becomes brittle due to the high crosslink density, there is also a drawback that the impact resistance is remarkably lowered in combination with the above-mentioned poor adhesion with the base material.
Japanese Patent Laid-Open No. 10-45926 JP 11-268192 A JP 2000-71391 A JP 2001-55540 A

  An object of the present invention is to provide a decorative sheet that can sufficiently ensure the adhesion to a base material and impact resistance against falling balls, even if a protective layer having a sufficient surface hardness is provided as a decorative material. It was made.

The present invention is a polyurethane-based resin layer on the substrate, on the polyurethane resin layer on a decorative sheet having a protective layer as the outermost layer, the polyurethane-based resin layer, and contains a polycarbonate skeleton and polyurethane backbone A decorative sheet comprising a reaction product of a hydroxyl group-containing resin (resin A), a polyol resin (resin B) other than the resin A, and a polyisocyanate curing agent (curing agent C) as a main component. It is.

  In particular, the decorative sheet is characterized in that the blending ratio (weight ratio) of the resin A and the resin B is 2: 8 to 8: 2.

  In particular, the decorative layer is a decorative sheet comprising an ionizing radiation curable resin.

  In particular, the decorative sheet is characterized in that the protective layer is made of a mixture of an ionizing radiation curable resin and a thermosetting resin.

  The decorative sheet of the present invention has a polycarbonate skeleton having an appropriate hardness to maintain the coating film skeleton and a polyurethane skeleton imparting flexibility at the same time between the base material and the protective layer as the outermost layer. The main component is a reaction product of a resin (resin A) that also contains a hydroxyl group that is included in the crosslinking reaction, another polyol resin (resin B), and a polyisocyanate curing agent (curing agent C). By providing a polyurethane-based resin layer, the surface hardness is maintained by the hardness of the polycarbonate skeleton, and the flexibility of the polyurethane skeleton allows the use of hard curable resins such as thermosetting resins and ionizing radiation curable resins. This reduces the influence of curing shrinkage stress of the protective layer and makes it strongly adhere to the substrate, and also reduces the impact received by the protective layer. Even if, while maintaining the surface hardness can be obtained tough decorative sheet or decorative material with sufficient adhesion and impact resistance.

  Specific forms of the decorative sheet of the present invention are roughly classified into the following two types.

  As shown in FIG. 1, the first is a decorative sheet in the form of a substrate 1 and a polyurethane resin layer 2 formed on the substrate 1. The decorative sheet of this form is applied on the surface of the base material for decorative material such as a wood base material with the surface opposite to the polyurethane resin layer 2 facing, and then on the polyurethane resin layer 2. A protective layer made of a thermosetting resin, an ionizing radiation curable resin, or the like as the outermost layer of the material is formed and used.

  As shown in FIG. 2, the second is a base material 1, a polyurethane resin layer 2 formed on the base material 1, and a protective layer as an outermost layer formed on the polyurethane resin layer 2. 3 is a decorative sheet in the form of 3. The decorative sheet in this form is laminated on the surface of a base material for a decorative material such as a wood-based base material, facing the surface opposite to the protective layer 3, and then forms a protective layer without forming a protective layer again. It is used as a material.

  In the state of the final decorative material provided for use as a building material or the like in any form of the decorative sheet, the protective layer 3 as the outermost layer is formed on the polyurethane resin layer 2. It is common to be used.

  The base material 1 in the decorative sheet of the present invention can be the same as the base material in the conventional decorative sheet. For example, paper such as thin paper, synthetic resin sheets (including films), metal foils, and the like. These may be laminated in any number of layers in any order. Moreover, arbitrary patterns, such as a grain, may be given between the surface, the back surface, and / or arbitrary layers. Of course, it does not matter if the surface of the substrate 1 is provided with uneven patterns such as a wood grain conduit groove.

  From the surface hardness and impact resistance aspects of the present invention, it is desirable that at least the surface of the substrate 1 is made of a synthetic resin sheet. Various sheets can be used as the synthetic resin sheet. Of these, a sheet made of a polyolefin resin such as polyethylene or polypropylene or a polyester resin such as polyethylene terephthalate or polybutylene terephthalate is most preferably used.

  The polyurethane-based resin layer 2 includes a polycarbonate skeleton and a polyurethane skeleton and a hydroxyl group-containing resin (resin A), a polyol resin (resin B) other than the resin A, a polyisocyanate curing agent (curing agent C), It can be formed by applying a mixture of and curing by reaction.

  As the resin A, it is possible to use a hydroxyl group-containing oligomer obtained by adding another polyol compound as a chain extender to a low molecular weight polycarbonate polyol compound as required, and reacting with a polyisocyanate compound of less than an equivalent amount. it can. As the resin B, for example, a polyester polyol resin, a polyether polyol resin, a polyurethane polyol resin (but not including a polycarbonate skeleton), an acrylic polyol resin, or the like can be used. The polycarbonate polyol resin can be used depending on the combination as long as it has a polycarbonate skeleton different from the polycarbonate skeleton contained in the resin A. From the viewpoint of the degree of freedom in designing physical properties, a polyol resin other than the polycarbonate polyol resin can be used. It is desirable to use

  The blending ratio of the resin A and the resin B is desirably in the range of 2: 8 to 8: 2 by weight ratio. If the resin A is less than this range, it is difficult to satisfy the impact resistance. Conversely, if the resin A is more than this range, the surface hardness tends to be insufficient.

  As the curing agent C, for example, general-purpose polyisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate can be used. it can. Of course, it may be a derivative such as an adduct, burette, or isocyanurate. Among them, good results can be obtained by using an aliphatic or alicyclic polyisocyanate compound having excellent flexibility.

  As the protective layer 3, a thermosetting resin or an ionizing radiation curable resin is used as in the conventional ordinary decorative sheet. Examples of thermosetting resins include polyurethane resins, acrylic resins, alkyd resins, melamine resins, urea resins, phenol resins, epoxy resins, polyester resins, silicone resins, and ionizing radiation curable resins. For example, a (meth) acrylate resin, an epoxy resin, a polyester resin, or the like is used.

  A mixed system of a thermosetting resin and an ionizing radiation curable resin can also be used. In particular, thermosetting type that reacts over time at a relatively low temperature, such as two-component curable polyurethane resin by reaction of polyol and isocyanate, or two-component curable epoxy resin using polyamine as a curing agent. When the resin is used in combination with an ionizing radiation curable resin, it becomes a semi-cured state instantaneously upon irradiation with ionizing radiation, so that it is excellent in handleability after the coating of the protective layer 3 is formed, and the thermosetting resin component However, since it hardens | cures, relaxing internal stress over time, the residual stress of the protective layer 3 becomes less, and the adhesiveness with the base material 1 and impact resistance can further be improved.

A primer resin layer was provided on the back surface of the olefin resin sheet subjected to wood grain printing, and a clear olefin resin sheet was laminated on the printed surface. Next, 50 parts by weight of a resin (A) having a polycarbonate skeleton and a polyurethane skeleton and containing a hydroxyl group, 50 parts by weight of a polyester polyol resin (B), 10 parts by weight of a hexamethylene diisocyanate curing agent (C), A coating solution obtained by diluting the mixed composition with an appropriate viscosity with a diluting solvent was applied to the surface of the clear olefin resin sheet by a direct natural gravure coating method, dried and thermally cured to form a polyurethane resin layer. After that, as a protective layer, the coating amount after applying a weather-resistant formulation to acrylate UV curable resin and diluting to an appropriate viscosity with a diluent solvent is dried by the direct reverse gravure coating method (circumferential speed ratio 150%). The decorative sheet of the present invention was completed by applying it at about 10 g / m ² and completely curing it by irradiating ultraviolet rays with a high-intensity high-pressure mercury lamp.

  In Example 1 above, 20 parts by weight of an equivalent amount of hexamethylene diisocyanate curing agent is mixed with 100 parts by weight of an acrylate-based ultraviolet curable resin and an acrylic polyol resin as a protective layer, and a weather resistance prescription is applied. A decorative sheet according to the present invention was completed under the same conditions as in Example 1 except that the coating liquid diluted to a proper viscosity was irradiated with ultraviolet rays and then completely cured by warm drying at 40 ° C.

[Comparative Example 1]
In the above Example 2, as a polyurethane resin layer, a mixed composition of 100 parts by weight of polyester polyol resin (B) and 10 parts by weight of hexamethylene diisocyanate curing agent (C) was adjusted to an appropriate viscosity with a diluent solvent. A decorative sheet was produced under the same conditions as in Example 2 except that the diluted coating solution was used.

[Comparative Example 2]
In Example 2 above, as the polyurethane resin layer, a mixture of 100 parts by weight of a resin (A) having a polycarbonate skeleton and a polyurethane skeleton and containing a hydroxyl group, and 10 parts by weight of a hexamethylene diisocyanate curing agent (C) A decorative sheet was prepared under the same conditions as in Example 2 above, except that the coating solution obtained by diluting the composition with a diluent solvent to an appropriate viscosity was used.

[Comparative Example 3]
In Example 2 above, as the polyurethane resin layer, 95 parts by weight of a resin (A) having a polycarbonate skeleton and a polyurethane skeleton and containing a hydroxyl group, 5 parts by weight of a polyester polyol resin (B), and a hexamethylene diisocyanate system A decorative sheet was prepared under the same conditions as in Example 2 above, except that the coating composition obtained by diluting the mixed composition with 10 parts by weight of the curing agent (C) with a diluent solvent to an appropriate viscosity was used.

[Comparative Example 4]
In Example 2, the polyurethane-based resin layer has a polycarbonate skeleton, a polyurethane skeleton and a hydroxyl group-containing resin (A ′) 50 parts by weight, and a polyester polyol resin (B) 50 parts by weight. A decorative sheet was prepared under the same conditions as in Example 2 except that a coating composition obtained by diluting a mixed composition with 10 parts by weight of a hexamethylene diisocyanate curing agent (C) to an appropriate viscosity with a diluent solvent was used. Produced.

[Evaluation]
Each decorative sheet prepared as described above was pasted onto a medium density fiberboard using an ethylene-vinyl acetate copolymer resin adhesive (with isocyanate curing agent), and then the decorative sheet was sufficiently clamped. The laminated decorative board is prepared for the surface hardness test, and the decorative board bonded in the same manner to the 12 mm thick plywood is prepared for the impact resistance test. The surface hardness test and the impact resistance test are performed as follows. Went.

  1. Surface hardness test: According to JIS K 5400 pencil hardness test, the pencil hardness was measured with a load of 1 kg.

  2. Impact resistance test: A dent state (such as a crack in the periphery) was observed when a 500 g steel ball was dropped from a height of 50 cm.

  The results are shown in Table 1 below.

It is a sectional side view which shows embodiment of the decorative sheet of this invention. It is a sectional side view which shows embodiment of the decorative sheet of this invention.

Explanation of symbols

1 Base material 2 Polyurethane resin layer 3 Protective layer

Claims (4)

Polyurethane resin layer on a base material, a decorative sheet having a protective layer as the outermost layer on the polyurethane resin layer, wherein the polyurethane-based resin layer contains a polycarbonate skeleton and polyurethane skeleton and containing a hydroxyl group A decorative sheet comprising as a main component a reaction product of a resin (resin A), a polyol resin (resin B) other than the resin A, and a polyisocyanate curing agent (curing agent C).   2. The decorative sheet according to claim 1, wherein a blending ratio (weight ratio) of the resin A and the resin B is 2: 8 to 8: 2. Decorative sheet according to claim 1 or 2, wherein the protective layer is characterized by comprising the ionizing radiation curable resin. The decorative sheet according to claim 1 or 2 , wherein the protective layer is made of a mixture of an ionizing radiation curable resin and a thermosetting resin.