JP2020078874A - Decorative laminate - Google Patents

Abstract

To provide a decorative laminate excellent not only in initial adhesiveness between a substrate and a decorative sheet, but also in final adhesiveness without occurrence of floating and peeling of the decorative sheet even in the case of having a groove part.SOLUTION: A decorative laminate includes a substrate and a decorative sheet, which are laminated through an adhesive. To a side part and a plane surface part of the substrate, the decorative sheet is continuously laminated. The adhesive is made from crystalline polyester polyol (a1-1) having a melting point of more than 80°C and 140°C or less as raw material. The amount of the crystalline polyester polyol (a1-1) used is in the range of 5 to 45 parts by mass in 100 parts by mass of a polyol (a) and a polyisocyanate (b) in total.SELECTED DRAWING: None

Description

  The present invention relates to a decorative board.

  BACKGROUND ART A decorative plate in which a decorative sheet is attached to a plate-shaped base material is widely used for building interior materials such as flooring materials, doors, fabrication members, and top plates. As the decorative board used for the flooring material, for example, a decorative sheet is attached to each base material, and the processed sheets are further joined together without any gaps. ) The method of constructing materials is widely adopted.

  However, it has been pointed out that in this method, since the decorative sheet is attached to each base material, the loss of the decorative sheet is large, and the construction time is long, so that the productivity is low. Instead of this, in recent years, a method of forming a large area floor material by forming a groove portion on a large area base material and integrally laminating a decorative sheet on it by vacuum lamination or the like has begun to be studied (for example, See Patent Document 1.).

  Examples of the adhesive that can be used for the processing include a urethane prepolymer having an isocyanate group obtained by reacting a polyol containing an alicyclic polyester polyol and an aliphatic polyester polyol with 4,4′-diphenylmethane diisocyanate. A moisture-curable polyurethane hot melt adhesive that does is known (for example, see Patent Document 2).

  However, the moisture-curable polyurethane hot melt adhesive has a problem that the decorative sheet is not sufficiently adhered to the groove portion of the base material, and the decorative sheet is lifted or peeled off.

JP 2004-74657 A JP, 2013-87150, A

  The problem to be solved by the present invention is to provide a decorative board having excellent initial adhesiveness between a base material and a decorative sheet, and having excellent final adhesiveness without floating or peeling of the decorative sheet. .

  The present invention is a decorative board in which a base material and a decorative sheet are bonded together via an adhesive, and the decorative sheet is continuously bonded to the side surface portion and the flat surface portion of the base material. Is a moisture-curable polyurethane hot melt adhesive containing a urethane prepolymer having an isocyanate group, which is a reaction product of the polyol (a) and the polyisocyanate (b), and the polyol (a) has a melting point of 80° C. The present invention provides a decorative board characterized by containing a crystalline polyester polyol (a1-1) having a temperature of 140°C or lower.

  The decorative board of the present invention has excellent initial adhesiveness between the base material and the decorative sheet, and also has excellent final adhesiveness without floating or peeling of the decorative sheet. In particular, even when the base material having a groove is used, the adhesiveness can be imparted to the groove without causing the decorative sheet to float or peel off.

  Therefore, the decorative board of the present invention can be applied to floor materials; lower foot doors, closet doors, kitchen doors, etc.; frame materials, picture frames, skirting boards, etc.; counter tables, furniture top boards, etc. It can be preferably used, and can be particularly preferably used as a floor material.

  The decorative plate of the present invention is a laminate of a base material and a decorative sheet via a specific adhesive, and the base material has a flat surface portion in the longitudinal direction and in at least one direction other than the longitudinal direction. It has a groove, and the decorative sheet is continuously attached to the side surface portion, the flat surface portion, and the groove portion provided in the flat surface portion of the base material.

  As the base material, for example, plate-like wood, laminated wood, plywood, wood base material such as MDF (medium density fiber board), particle board; inorganic base material such as hard cement calcium silicate board can be used. it can.

  The thickness, width, and length of the base material are appropriately determined depending on the intended use of the decorative board, for example, 600 to 4,000 mm in length, 50 to 5,000 mm in width, The thickness is in the range of 2 to 18 mm.

  As the base material, either a grooved material or a grooveless material can be used. When a material having a groove is used as the base material, its longitudinal direction (indicates a direction in which the width is long. When the widths are the same vertically and horizontally, one of them is indicated), and at least other than the longitudinal direction. It is possible to use one having a groove in one direction. The number of grooves in the longitudinal direction may be one or two or more, and the number of grooves other than those in the longitudinal direction may be one or two or more. The direction of the groove other than the longitudinal direction is preferably perpendicular to the longitudinal direction from the viewpoint that it is most frequently used and that the decorative sheet easily follows the groove portion in line production.

  Examples of the groove of the base material include a cylindrical groove, a triangular groove, a flat groove, and a dovetail groove. These grooves may be used alone or in combination of two or more. Among these, the triangular groove is preferable because it is frequently used as a floor material and the like, and the followability to the groove portion of the decorative sheet is good.

  The depth of the groove is appropriately determined according to the use of the decorative plate, and is, for example, in the range of 0.5 to 3 mm. The width of the groove is, for example, in the range of 0.5 to 3 mm.

  The decorative sheet that can be used in the present invention may be plain or may have a decorative color or pattern. Examples of the material of the decorative sheet include resins such as polyvinyl chloride, polyolefin, polymethyl methacrylate, polyester, polyamide, polystyrene, polycarbonate, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyethylene, polypropylene; Examples include paper, non-woven fabric, woven fabric, wooden thin decorative veneer, tatami mat, and the like. Among these, polyvinyl chloride, polyolefin, polymethylmethacrylate, and polyester are preferably used from the viewpoint of conformability to the groove.

  The thickness of the decorative sheet is preferably 0.05 to 0.3 mm, more preferably 0.1 to 0.2 mm from the viewpoint of excellent followability to the groove.

  A predetermined adhesive, which will be described later, is used to bond the base material and the decorative sheet together. The adhesive layer may be appropriately determined as long as sufficient adhesiveness can be obtained, and for example, a range of 0.03 to 0.15 mm can be mentioned.

  The decorative board of the present invention is one in which the base material and the decorative sheet are bonded together, and the decorative sheet may be continuously bonded at the side surface portion and the flat surface portion of the base material. When the groove is provided, the decorative sheet is also attached to the groove provided on the flat surface of the base material. In addition, a decorative sheet may be attached to the back surface (back side of the flat surface) of the base material.

  Next, a method for manufacturing a decorative board of the present invention will be described.

  As a method of manufacturing the decorative plate in the case where a material having no groove is used as the base material, for example, an adhesive is applied on the decorative sheet, and the decorative sheet and the base material plane, the side surface, and, depending on the case, There is a method of bonding the back surface.

  In addition, as a method for manufacturing the decorative plate when a material having a groove is used as the base material, for example, an adhesive is applied on the decorative sheet to form a decorative sheet and a base material plane having the groove. And (i) after that, the decorative sheet, which corresponds to the groove of the base material, is locally heated to locally soften the decorative sheet and press-bond it to the groove of the base material; (ii) ) Then, a method of integrally laminating by vacuum lamination (hereinafter, abbreviated as "vacuum lapping molding") and the like can be mentioned. The vacuum lamination may be performed while applying heat of 70 to 140° C., for example. Among these, it is preferable to employ the above (ii) because a decorative board can be easily obtained. In the present invention, the above-mentioned (ii) can be preferably adopted by using a specific adhesive described later.

  Next, the adhesive used in the present invention will be described.

  The adhesive is a moisture-curable polyurethane hot melt adhesive containing a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol (a) and a polyisocyanate (b), and has a specific melting point as its raw material. It is essential to use the crystalline polyester polyol (a1-1).

  The crystalline polyester polyol (a1-1) is required to have a melting point of more than 80° C. and 140° C. or less in order to impart excellent adhesiveness. By using the crystalline polyester polyol having such a melting point range, a high cohesive force can be imparted when the sheet is heated and made to follow the groove portion, and therefore it is presumed that excellent initial adhesiveness can be obtained. The melting point of the crystalline polyester polyol (a1-1) is preferably in the range of 85 to 130° C., more preferably in the range of 90 to 120° C., from the viewpoint that more excellent initial adhesiveness can be obtained. The range of 95 to 110°C is more preferable.

  In addition, the amount of the crystalline polyester polyol (a1-1) used is 100 parts by mass in total of the polyol (a) and the polyisocyanate (b) from the viewpoint that more excellent initial adhesiveness and workability can be obtained. The range is preferably 5 to 45 parts by mass, more preferably 8 to 43 parts by mass, more preferably 10 to 42 parts by mass, further preferably 15 to 41 parts by mass, and 30 to 40 parts by mass. The range of parts by mass is particularly preferred.

  As the crystalline polyester polyol (a1-1), specifically, for example, a reaction product of a compound having two or more hydroxyl groups and a polybasic acid can be used.

  Examples of the compound having a hydroxyl group include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, trimethylolpropane, trimethylolethane, glycerin, neopentyl glycol. , Trimethylolpropane, etc. can be used. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use at least one compound selected from the group consisting of butanediol, hexanediol, octanediol and decanediol from the viewpoint of enhancing the crystallinity and further improving the initial adhesiveness.

  Examples of the polybasic acid that can be used include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, and phthalic anhydride. . These polybasic acids may be used alone or in combination of two or more kinds. Among these, 1 selected from the group consisting of adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, and phthalic anhydride from the viewpoint of enhancing crystallinity and further improving initial adhesiveness. It is preferable to use one or more polybasic acids.

  The melting point of the crystalline polyester polyol (a1-1) correlates with the high crystallinity, and it is preferable to use a highly crystalline polyester polyol. The melting point and crystallinity of the polyester polyol can be adjusted by selection of raw material monomers, copolymer composition, average molecular weight and the like. In the present invention, the term "crystalline" means that the peak of crystallization heat or the heat of fusion can be confirmed in DSC (differential scanning calorimeter) measurement according to JIS K7121:2012, and is "amorphous". Indicates that the peak cannot be confirmed. The method for measuring the melting point of the crystalline polyester polyol (a1-1) will be described in Examples.

  A preferred composition of the crystalline polyester polyol (a1-1) is a reaction of hexanediol, sebacic acid, and phthalic acid (one or more selected from the group consisting of isophthalic acid, terephthalic acid, and orthophthalic acid). Things can be mentioned.

  The number average molecular weight of the crystalline polyester polyol (a1-1) is in the range of 500 to 5,000 from the viewpoint that the melting point can be easily adjusted, and more excellent initial adhesiveness and workability can be obtained. Is preferable, the range of 1,000 to 4,500 is more preferable, and the range of 2,000 to 4,000 is further preferable. The number average molecular weight of the crystalline polyester polyol (a1-1) is a value measured by a gel permeation chromatography (GPC) method.

  The polyol (a) preferably further contains a crystalline polyester polyol (a1-2) having a melting point of 40 to 80°C. By using the above-mentioned (a1-2), it is possible to satisfy both the permeability to the base material and the crystallinity, and it is possible to obtain further excellent initial adhesiveness.

  As the crystalline polyester polyol (a1-2), the same raw material as in the above (a1-1) can be used, and preferably, the compound having two or more hydroxyl groups is ethylene glycol, butanediol, and hexane. It is preferable to use at least one compound selected from the group consisting of diols, and as the polybasic acid, at least one polybasic acid selected from the group consisting of adipic acid, sebacic acid, and dodecanedicarboxylic acid is used. It is preferable.

  The method for measuring the melting point of the crystalline polyester polyol (a1-2) is the same as that of the crystalline polyester polyol (a1-1).

  The number average molecular weight of the crystalline polyester polyol (a1-2) is preferably in the range of 500 to 5,000, and more preferably 1,500 to 4,500, from the viewpoint of obtaining more excellent initial adhesiveness. Is more preferable, and the range of 2,000 to 4,000 is even more preferable. The number average molecular weight of the crystalline polyester polyol (a1-2) is a value measured by a gel permeation chromatography (GPC) method.

  Further, as the crystalline polyester polyol (a1-2), polycaprolactone polyol can be used in addition to those described above. As the polycaprolactone polyol, a reaction product of the compound having two or more hydroxyl groups and ε-caprolactone can be used.

  When polycaprolactone polyol is used as the (a1-2), the number average molecular weight is preferably in the range of 5,000 to 200,000 from the viewpoint that the open time and the initial adhesiveness can be further improved, The range of 10,000 to 150,000 is more preferable, and the range of 30,000 to 100,000 is further preferable. The number average molecular weight of the polycaprolactone polyol is a value measured by a gel permeation chromatography (GPC) method.

  The total amount of the crystalline polyester polyols (a1-1) and (a1-2) used is 100 parts by mass in total of the polyol (a) and the polyisocyanate (b), from the viewpoint that further excellent adhesiveness can be obtained. It is preferably 50 parts by mass or more, and more preferably 50 to 80 parts by mass.

  In addition to the above-mentioned (a1-1) and (a1-2), other polyols may be used in combination with the above-mentioned polyol (a).

  As the other polyols, for example, polyester polyols other than the above (a1-1) and (a1-2), polyether polyols, polyacrylic polyols, polycarbonate polyols and the like can be used. These polyols may be used alone or in combination of two or more. Among these, it is preferable to use a polyester polyol other than the above-mentioned (a1-1) and (a1-2), because further adhesion can be obtained. The number average molecular weight of the polyester polyol other than (a1-1) and (a1-2) is preferably in the range of 500 to 10,000. The number average molecular weight of the polyester polyol is a value measured by a gel permeation chromatography (GPC) method.

  Examples of the polyisocyanate (b) include aromatic diisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl. Diisocyanates (b-1) such as aliphatic or alicyclic diisocyanates such as methane diisocyanate and tetramethylxylylene diisocyanate; isocyanurate compounds (b-2) which are dimers of these diisocyanates; adduct compounds; burette compounds; allophanate Compounds; polymethylene polyphenyl polyisocyanate (b-3) and the like can be used. These isocyanates may be used alone or in combination of two or more.

  Among the above-mentioned ones, the polyisocyanate (b) preferably contains a diisocyanate (b-1) from the viewpoint of good reactivity and adhesiveness, and the diisocyanate (b-1) is an aromatic compound. Polyisocyanates are preferred, and diphenylmethane diisocyanate is more preferred. Further, as the polyisocyanate (b), in addition to the above (b-1), an isocyanurate compound (b-2), and, in addition to the above (b-1), further excellent final adhesiveness and heat resistance can be obtained. It is preferable to use polymethylene polyphenyl polyisocyanate (b-3), and it is more preferable to use (b-2) and (b-3) together.

  As the isocyanurate compound (b-2), it is preferable to use an aliphatic isocyanurate compound from the viewpoint of obtaining more excellent final adhesiveness and heat resistance. The amount of the isocyanurate compound (b-2) used is preferably in the range of 0.1 to 30% by mass, more preferably 5 to 25% by mass in the polyisocyanate (b). , 8 to 23 mass% is more preferable.

（式（２）中、ｎは１以上の整数である。） The polymethylene polyphenyl polyisocyanate (b-3) is specifically one represented by the following formula (2), preferably n in the formula (2) is an integer of 1 to 5. is there.

(In the formula (2), n is an integer of 1 or more.)

  The amount of the polymethylene polyphenyl polyisocyanate (b-3) to be used is 0.1 to 0.1 in the polyisocyanate (b) from the viewpoint that more excellent final adhesiveness and heat resistance can be obtained. It is preferably in the range of 30% by mass, more preferably in the range of 5 to 25% by mass, still more preferably in the range of 8 to 23% by mass.

  The urethane prepolymer is obtained by reacting the polyol (a) with the polyisocyanate (b), and reacts with water present in the air or a base material to which the urethane prepolymer is applied. It has an isocyanate group capable of forming a crosslinked structure.

  As a method for producing the urethane prepolymer, for example, a reaction vessel containing the polyisocyanate (b) is heated after dropping the mixture of the polyol (a), and the isocyanate group contained in the polyisocyanate (b) is Can be produced by reacting the polyol (a) with an excess of the hydroxyl group.

  When the urethane prepolymer is produced, unreacted polyisocyanate is reduced at a high temperature as a molar ratio (NCO/OH) of the hydroxyl group of the polyol (a) and the isocyanate group of the polyisocyanate (b). From the viewpoint that a high cohesive force can be imparted, the range is preferably from 1.5 to 5, more preferably from 1.8 to 3, and even more preferably from 2.2 to 2.6.

  The isocyanate group content (hereinafter abbreviated as “NCO%”) of the urethane prepolymer obtained by the above method is 1 to 10% by mass from the viewpoint that the adhesiveness at high temperature can be further improved. The range is preferable, the range of 2 to 5 mass% is more preferable, the range of 2.5 to 4.5 mass% is further preferable, and the range of 3 to 4.5 mass% is particularly preferable. The NCO% of the urethane prepolymer is a value measured by potentiometric titration according to JIS K1603-1:2007.

  The moisture-curable polyurethane hot melt resin composition of the present invention contains the urethane prepolymer, but may contain other additives as required.

  Examples of the other additives include curing catalysts, antioxidants, tackifiers, plasticizers, light stabilizers, fillers, dyes, pigments, defoamers, optical brighteners, silane coupling agents, waxes. , A thermoplastic resin, etc. can be used. These additives may be used alone or in combination of two or more.

  As described above, the decorative sheet of the present invention is excellent in initial adhesion between the base material and the decorative sheet even when a decorative sheet having a groove is used, and is excellent in that the decorative sheet does not float or peel off. It has final adhesiveness.

  Therefore, the decorative board of the present invention is applied to floor materials; lower foot doors, closet doors, kitchen doors, etc.; frame materials, picture frames, baseboards, etc.; counter tables, furniture top boards, etc. It can be preferably used, and can be particularly preferably used as a floor material.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1] <Preparation of adhesive>
A 4-necked flask equipped with a stirrer, a thermometer, an inert gas inlet, and a reflux condenser was reacted with crystalline polyester polyol (hexanediol, terephthalic acid, and sebacic acid, melting point: 100°C, number average). Molecular weight: 2,000, hereinafter abbreviated as “crystalline PEs-1”. 23 parts by mass, crystalline polyester polyol (those obtained by reacting hexanediol and dodecanedicarboxylic acid, melting point; 72° C., number average molecular weight; 3 , 500, hereinafter abbreviated as “crystalline PEs-2”) 40 parts by mass, crystalline polyester polyol (polycaprolactone polyol, melting point; 50° C., number average molecular weight; 80,000, hereinafter “crystalline PEs-3”) 10 parts by mass, other polyester polyols (reacted with ethylene glycol, neopentyl glycol, hexanediol, and adipic acid, number average molecular weight: 5,000, hereinafter abbreviated as “other PEs-1”) 5 parts by mass, 2 parts by mass of polyoxyethylene polyoxypropylene glycol (number average molecular weight; 4,000, hereinafter abbreviated as “PEt-1”) are charged, and water content is obtained by heating under reduced pressure at 90° C. It dehydrated until the rate became 0.05 mass% or less.
Then, after cooling the temperature in the reaction vessel to 60° C., 11 parts by mass of diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”), polymethylene polyphenyl polyisocyanate (“Millionate MR-200” manufactured by Tosoh Corporation, hereinafter “ 2 parts by mass, and 3 parts by mass of an isocyanurate compound of hexamethylene diisocyanate (hereinafter abbreviated as “HDI nurate”) are added, and NCO% is kept constant at 100° C. under a nitrogen atmosphere. A urethane prepolymer was obtained by reacting for about 3 hours.
The NCO/OH of the obtained urethane prepolymer was 2.39, and the NCO% of the urethane prepolymer was 2.95% by mass.

<Production of decorative board>
Using a T die coater, the urethane prepolymer is applied to a thickness of 60 μm on the back surface of a vinyl chloride type decorative sheet with a wood pattern (thickness 130 μm, softening point 50° C., abbreviated as “PVC” hereinafter). Then, the adhesive layer is used as a base material (length 30 cm, width 20 cm, thickness 12 mm, MDF, lengthwise 15 cm, width 10 cm triangular rectangular groove (groove width 1 mm, depth 0.8 mm)). 3D vacuum lapping is performed by laminating only on the flat surface portion, using an arbitrary 3D vacuum laminating machine, reducing the pressure to 0.01 MPa at 110° C., and leaving it for 1 minute, and the side surface portion of the base material, and A decorative board was obtained in which the decorative sheets were continuously laminated in the groove provided on the flat surface.

[Example 2]
In a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a reflux condenser, 23 parts by mass of crystalline PEs-1, 25 parts by mass of crystalline PEs-2, and 10 parts of crystalline PEs-3. 15 parts by mass, crystalline polyester polyol (a reaction product of hexanediol and adipic acid, melting point; 58° C., number average molecular weight; 4,500, abbreviated as “crystalline PEs-4” hereinafter), and the like. 5 parts by mass of PEs-1 and 2 parts by mass of PEt-1 were charged and dehydrated by heating at 90° C. under reduced pressure until the water content became 0.05% by mass or less.
Then, after cooling the temperature in the reaction vessel to 60° C., 11 parts by mass of MDI, 2 parts by mass of polymeric MDI and 3 parts by mass of HDI nitrate were added, and the temperature was raised to 110° C. to keep the isocyanate group content constant. The resulting mixture was allowed to react for about 3 hours, and then under a nitrogen atmosphere until the NCO% became constant at 100° C. for about 3 hours to obtain a urethane prepolymer.
The NCO/OH of the obtained urethane prepolymer was 2.49, and the NCO% of the urethane prepolymer was 3.03% by mass.
Using this urethane prepolymer, a decorative board was obtained in the same manner as in Example 1.

[Example 3]
30 parts by mass of crystalline PEs-1, 30 parts by mass of crystalline PEs-2, and 10 parts of crystalline PEs-3 were placed in a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a reflux condenser. 10 parts by mass of PEs-1 and 2 parts by mass of PEt-1 were charged and dehydrated by heating under reduced pressure at 90° C. until the water content became 0.05% by mass or less.
Then, after cooling the temperature in the reaction vessel to 60° C., 13 parts by mass of MDI, 2 parts by mass of polymeric MDI and 3 parts by mass of HDI nitrate were added, and the temperature was raised to 110° C. to keep the isocyanate group content constant. The resulting mixture was allowed to react for about 3 hours, and then under a nitrogen atmosphere until the NCO% became constant at 100° C. for about 3 hours to obtain a urethane prepolymer.
The NCO/OH of the obtained urethane prepolymer was 2.62, and the NCO% of the urethane prepolymer was 3.55% by mass.
Using this urethane prepolymer, a decorative board was obtained in the same manner as in Example 1.

[Example 4]
42 parts by mass of crystalline PEs-1, 20 parts by mass of crystalline PEs-2, and 10 parts of crystalline PEs-3 were placed in a 4-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a reflux condenser. 10 parts by mass of PEs-1 and 2 parts by mass of PEt-1 were charged, and the mixture was dehydrated by heating at 90° C. under reduced pressure until the water content became 0.05% by mass or less.
Then, after cooling the temperature in the reaction vessel to 60° C., 19 parts by mass of MDI, 2 parts by mass of polymeric MDI and 3 parts by mass of HDI nitrate were added, and the temperature was raised to 110° C. to keep the isocyanate group content constant. The resulting mixture was allowed to react for about 3 hours, and then under a nitrogen atmosphere until the NCO% became constant at 100° C. for about 3 hours to obtain a urethane prepolymer.
The NCO/OH of the obtained urethane prepolymer was 2.07, and the NCO% of the urethane prepolymer was 2.61% by mass.
Using this urethane prepolymer, a decorative board was obtained in the same manner as in Example 1.

[Example 5]
42 parts by mass of crystalline PEs-1, 10 parts by mass of crystalline PEs-2, and 10 parts of crystalline PEs-3 were placed in a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a reflux condenser. 10 parts by mass of crystalline PEs-4, 10 parts by mass of other PEs-1 and 2 parts by mass of PEt-1 were charged, and the moisture content was 0.05% by mass or less by heating under reduced pressure at 90°C. It was dehydrated until it became.
Then, after cooling the temperature in the reaction vessel to 60° C., 11 parts by mass of MDI, 2 parts by mass of polymeric MDI and 3 parts by mass of HDI nitrate were added, and the temperature was raised to 110° C. to keep the isocyanate group content constant. The resulting mixture was allowed to react for about 3 hours, and then under a nitrogen atmosphere until the NCO% became constant at 100° C. for about 3 hours to obtain a urethane prepolymer.
The NCO/OH of the obtained urethane prepolymer was 2.11 and the NCO% of the urethane prepolymer was 2.67% by mass.
Using this urethane prepolymer, a decorative board was obtained in the same manner as in Example 1.

[Example 6]
Crystalline polyester polyol (hexanediol, terephthalic acid, and adipic acid reacted in a 4-necked flask equipped with a stirrer, thermometer, inert gas inlet, and reflux condenser, melting point: 96°C, number average Molecular weight: 3,500, abbreviated as "crystalline PEs-5" hereinafter) 42 parts by mass, crystalline PEs-2 23 parts by mass, crystalline PEs-3 10 parts by mass, and other PEs-1 10 parts. 2 parts by mass of PEt-1 and 2 parts by mass of PEt-1 were charged and dehydrated by heating at 90° C. under reduced pressure until the water content became 0.05% by mass or less.
Then, after cooling the temperature in the reaction vessel to 60° C., 8 parts by mass of MDI, 2 parts by mass of polymeric MDI and 3 parts by mass of HDI nitrate were added, and the temperature was raised to 110° C. to keep the isocyanate group content constant. The resulting mixture was allowed to react for about 3 hours, and then reacted under a nitrogen atmosphere until the NCO% became constant at 100° C. for about 3 hours to obtain a urethane prepolymer.
The NCO/OH of the obtained urethane prepolymer was 2.30, and the NCO% of the urethane prepolymer was 2.29% by mass.
Using this urethane prepolymer, a decorative board was obtained in the same manner as in Example 1.

[Comparative Example 1]
30 parts by mass of crystalline PEs-2, 10 parts by mass of crystalline PEs-3 and 30 parts of crystalline PEs-4 were placed in a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a reflux condenser. 10 parts by mass of PEs-1 and 2 parts by mass of PEt-1 were charged, and the mixture was dehydrated by heating at 90° C. under reduced pressure until the water content became 0.05% by mass or less.
Next, after cooling the temperature in the reaction vessel to 60° C., 18 parts by mass of MDI was added, the temperature was raised to 110° C., and the reaction was continued for about 3 hours until the isocyanate group content became constant, and urethane having an isocyanate group A prepolymer was obtained. The NCO/OH of the obtained urethane prepolymer was 2.77, and the NCO% of the urethane prepolymer was 3.86% by mass. Using this urethane prepolymer, a decorative board was obtained in the same manner as in Example 1.

[Measurement method of number average molecular weight]
The number average molecular weight of the polyols used in Examples and Comparative Examples is a value measured by the gel permeation chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSK gel G4000" (7.8 mm ID x 30 cm) x 1 "TSK gel G3000" (7.8 mm ID x 30 cm) x 1 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
Tosoh Corporation "TSK gel standard polystyrene A-500"
Tosoh Corporation "TSK gel standard polystyrene A-1000"
Tosoh Corporation "TSK gel standard polystyrene A-2500"
Tosoh Corporation "TSKgel Standard Polystyrene A-5000"
"TSK gel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSK gel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSK gel standard polystyrene F-4" manufactured by Tosoh Corporation
Tosoh Corporation "TSK gel standard polystyrene F-10"
Tosoh Corporation "TSK gel standard polystyrene F-20"
Tosoh Corporation "TSK gel standard polystyrene F-40"
"TSK gel standard polystyrene F-80" manufactured by Tosoh Corporation
Tosoh Corporation “TSKgel Standard Polystyrene F-128”
Tosoh Corporation "TSK gel standard polystyrene F-288"
Tosoh Corporation "TSK gel standard polystyrene F-550"

[Measuring method of melting point of crystalline polyester polyol]
10 mg of each crystalline polyester polyol was weighed in a measuring container, and using a suggestive scanning calorimeter (“DSC 220C” manufactured by Seiko Denshi KK), nitrogen gas flow rate was 50 ml/min and heating rate was 10° C./min. After raising the temperature from ℃ to 210 ℃, and then holding it at 210 ℃ for 3 minutes, the temperature was lowered to -100 ℃ at a cooling rate of 50 ℃ / min, and the secondary temperature was raised to 200 ℃ again, and it was drawn on the chart. The melting point (°C) was determined from the obtained DSC curve.

[Adhesion evaluation method]
The adhesiveness was evaluated by the following two methods.

<3D molding test>
After the decorative plate prepared by the above method was cured at 23° C. for 5 days, the side surface and the cross section of the groove were observed to evaluate the 3D formability.
"○": No floating of the decorative sheet was confirmed.
"B": Some floating of the decorative sheet was confirmed, but there was no problem in practical use.
“X”: Adhesion could not be achieved.

<Creep test>
The urethane prepolymers obtained in Examples and Comparative Examples were each melted at a temperature of 120° C. for 1 hour. The adhesive was applied onto a polyethylene terephthalate sheet using an applicator so that the thickness was 50 μm. It was left at 23° C. for 15 minutes and then at 80° C. for 2 minutes. MDF (Medium Density Fiber Board) was laminated on the coating layer and pressure-bonded with a pressure roller. A load of 75 g was applied to the test piece having a width of 25 mm after pressure bonding in the 90° direction, and the peeled length (mm) of the polyethylene terephthalate sheet after 15 minutes was measured and evaluated as follows.
"O": The peel length was 2 mm or less.
"B": The peel length was more than 2 mm and 10 mm or less.
"X": The peeling length exceeded 10 mm, or the weight dropped.

  It was found that the decorative board of the present invention has excellent initial adhesiveness between the base material and the decorative sheet, and also has excellent final adhesiveness to the grooved base material without the floating or peeling of the decorative sheet. It was

  On the other hand, in Comparative Example 1, the crystalline polyester polyol (a1-1) was not used, but the adhesiveness was poor.

Claims (9)

A decorative board in which a base material and a decorative sheet are bonded together via an adhesive,
The decorative sheet is continuously attached to the side surface portion and the flat surface portion of the base material,
The adhesive is
A moisture-curable polyurethane hot melt adhesive containing a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol (a) and a polyisocyanate (b),
The polyol (a) is
A decorative board comprising a crystalline polyester polyol (a1-1) having a melting point of more than 80°C and 140°C or less. The decorative board according to claim 1, wherein the amount of the crystalline polyester polyol (a1-1) used is in the range of 5 to 45 parts by mass in the total 100 parts by mass of the polyol (a) and the polyisocyanate (b). The decorative board according to claim 1 or 2, wherein the polyol (a) further contains a crystalline polyester polyol (a1-2) having a melting point of 40 to 80°C. The cosmetic according to claim 3, wherein the total amount of the crystalline polyester polyols (a1-1) and (a1-2) used is 50 parts by mass or more based on 100 parts by mass of the total amount of the polyol (a) and the polyisocyanate (b). Board. The decorative board according to claim 3 or 4, wherein the polyol (a) further contains a polyester polyol (a1-3) other than the (a1-1) and (a1-2). The cosmetic according to any one of claims 1 to 5, wherein the molar ratio [NCO/OH] of the hydroxyl group of the polyol (a) and the isocyanate group of the polyisocyanate (b) is in the range of 1.5 to 5. Board. The decorative board according to any one of claims 1 to 6, wherein the polyisocyanate (b) contains a diisocyanate (b-1). The decorative board according to claim 7, wherein the polyisocyanate (b) further contains an isocyanurate compound (b-2) and/or a polymethylene polyphenyl polyisocyanate (b-3). The decorative plate according to any one of claims 1 to 8, wherein the decorative plate is obtained by vacuum lapping molding.