JP2007138461A - Building material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-manufacture building material which is excellent in strength, the shape of a surface and heat resistance, even in the use of a wood base material with a defective surface or insufficient strength, and a manufacturing method for the building material. <P>SOLUTION: This manufacturing method for the building material is equipped with a step of thermally pressing the wood base material and a sheet material for imparting designability, in a state in which a reactive hot-melt adhesive, containing a prepolymer with a skeleton comprising at least either a crystalline component with a melting point of 50°C or higher, or a noncrystalline component with a glass transition point of 30°C or higher, is interposed between the wood base material and the sheet material for imparting the designability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a building material used as a flooring material, a wall material, a ceiling material, and the like, and a manufacturing method thereof.

As a building material used for a flooring material, a wall material, a ceiling material, or the like, a sheet material that imparts designability to the surface of a wooden substrate with an adhesive is used (for example, Patent Document 1, 2).
In other words, by using solid wood or synthetic wood such as plywood obtained from relatively inexpensive trees as a wooden substrate, the design material is greatly improved by pasting a sheet material that imparts design properties to the surface of this wooden substrate. However, it is possible to obtain a building material with high design properties at a low cost, such as a solid wood obtained from high-quality trees.

However, in recent years, there has been a tendency for deforestation to shrink due to environmental considerations, and it has become difficult to obtain high-quality and inexpensive timber as a wooden base material.
In particular, for materials such as solid wood and plywood that are greatly affected by the quality of the original wood, there is a concern about the deterioration of the quality. That is, there are cases where a node hole is formed on the surface, the surface is not smooth, or a wooden base material having insufficient strength must be used.

  Therefore, even when using a wood substrate with a surface defect or reduced strength, the important issue is how to cover defects such as nodal holes and recesses on the surface and a decrease in strength, and make it a good building material. It is becoming.

  In the above building materials, a vinyl acetate emulsion adhesive is generally used as an adhesive. However, when a sheet material that imparts design properties to a wooden substrate is bonded using a vinyl acetate emulsion-based adhesive, defects such as node holes and recesses on the surface of the wooden substrate cannot be filled. It was difficult to obtain a good surface strength improvement effect. In addition, as a method of filling defects such as joint holes and recesses on the surface of the wooden substrate, there is a method of filling putty materials into the joint holes and recesses, etc., but the process of filling the putty material and polishing the putty material protruding from the joint holes and recesses Therefore, an extra process for removing and smoothing is required, and the manufacturing work becomes complicated.

JP 2000-190309 A JP 2002-276140 A

  Then, the inventor of this invention thought that the said problem could be solved if the sheet material which provides designability was stuck on the surface of a wooden base material using a hot-melt-adhesive. In other words, hot melt adhesives are usually 100% solids, and by selecting those that have a small volume shrinkage due to cooling and solidification, they enter into holes and recesses on the surface of the wooden substrate simultaneously with adhesion, and improve smoothness. It is thought that you can.

However, EVA (ethylene-vinyl acetate copolymer) -based adhesives have been widely used as hot melt adhesives, but EVA is thermoplastic and therefore hardly exhibits heat resistance. It is difficult to apply to a member whose temperature is increased by heating or direct sunlight. In general, the volume shrinkage during cooling is relatively large and is not very suitable for the purpose of the present invention.
As a result of diligent examination of various adhesives, the inventors have found that it is effective to use a reactive hot melt adhesive having specific properties, and have completed the present invention.

  In view of the above circumstances, the present invention is excellent in strength, excellent in surface shape, excellent in heat resistance, and easy to manufacture even if a wooden substrate having a surface defect or insufficient strength is used. It aims at providing a building material and its manufacturing method.

  In order to achieve the above object, the building material according to claim 1 of the present invention (hereinafter referred to as “building material according to claim 1”) imparts design properties to the surface of the wooden substrate through an adhesive layer. A prepolymer having a skeleton having at least one of a crystalline component having a melting point of 50 ° C. or higher and a non-crystalline component having a glass transition point of 30 ° C. or higher. It is characterized by being formed of a reactive hot melt adhesive containing (A).

  The building material according to claim 2 of the present invention (hereinafter referred to as "building material of claim 2") is the building material according to claim 1, wherein the reactive hot melt adhesive is prepolymer (A ) In an amount of 40% by weight or more.

  The building material according to claim 3 of the present invention (hereinafter referred to as “building material of claim 3”) is the building material according to claim 1 or 2, wherein the prepolymer (A) is substantially composed of a main chain. In particular, it is a polyester skeleton, and is characterized in that a compound (C) having a plurality of isocyanate groups is added to the hydroxyl group of the compound (B) having a hydroxyl group exceeding 1 on average.

  The building material according to claim 4 of the present invention (hereinafter referred to as "building material of claim 4") is the building material according to any one of claims 1 to 3, wherein the impact strength of the wooden substrate is Using a DuPont impact tester on a wood substrate that has been left for 24 hours or more in an environment of 20 ° C. and 60% Rh, using a DuPont impact tester in an environment of 20 ° C. and 60% Rh, The concave depth formed when the weight is dropped from a height of 300 mm is 0.5 mm or more on average.

  The building material according to claim 5 of the present invention (hereinafter referred to as “building material according to claim 5”) is a sheet material that imparts designability in any of the building materials according to claims 1 to 4. It is characterized by being a paper-based material weighing less than 50 g per square meter.

  In the manufacturing method of the building material of Claim 6 of this invention, in manufacturing the building material in any one of Claims 1-5, between the woody base material and the sheet material which provides designability, In the state of interposing a reactive hot melt adhesive containing a prepolymer (A) having at least one of a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a glass transition point of 30 ° C. or higher in the skeleton, It is characterized by comprising a step of hot pressing a wooden substrate and a sheet material imparting design properties.

The reactive hot melt adhesive used in the present invention has at least one of a crystalline component having a melting point of 50 ° C. or higher and a non-crystalline component having a glass transition point (hereinafter referred to as “Tg”) of 30 ° C. or higher. Although it will not specifically limit if it contains the prepolymer (A) which it has in it, It is preferable to contain the said prepolymer (A) 40weight% or more.
That is, when the prepolymer (A) is contained in an amount exceeding 0% by weight and less than 40% by weight, the effect of improving the surface hardness of the laminated building material may not be sufficiently obtained. In particular, in the production process, it is important for maintaining the hardness until the moisture curing reaction proceeds after cooling and solidification. Further, even when the moisture curing is substantially completed, it is also important for maintaining the surface hardness of the building material of the present invention.

In the prepolymer (A), the melting point of the crystalline component is limited to 50 ° C. or higher,
The reason is that when the melting point is lower than 50 ° C., the effect of improving the surface hardness of the laminated building material cannot be obtained. Also, the melting point of the crystalline component is preferably as high as possible because the surface temperature of the building material rises and the melting point of the crystalline component exceeds the melting point of the crystalline component and the surface hardness decreases. If it is too high, the open time will be shortened, and it is necessary to set the coating temperature high, or the heating temperature at the time of hot pressing needs to be set high. Problems such as heat deterioration of the adhesive easily occur. Therefore, the melting point of the crystalline component is preferably 50 ° C. or higher and 150 ° C. or lower, more preferably 55 ° C. or higher and 130 ° C. or lower, and further preferably 60 ° C. or higher and 100 ° C. or lower. In addition, when determining the content of the prepolymer (A) in the reactive hot melt adhesive, the melting point of the entire adhesive is one index, so the melting point of the entire adhesive is more preferably 50 ° C. or more. The content of the prepolymer (A) is preferably set so as to be 60 ° C. or higher, more preferably 70 ° C. or higher. In addition, the upper limit of the melting point of the entire adhesive is preferably set to 120 ° C. or less, and preferably 100 ° C. or less, in order to maintain good workability as a reactive hot melt adhesive. In addition, if the melting point of the crystalline component is high, curing is easy to obtain even if the content of the prepolymer (A) is small. Conversely, if the crystalline component having a low melting point is used, the prepolymer (A) content A larger amount is desirable.

  On the other hand, in the prepolymer (A), the Tg of the amorphous component is limited to 30 ° C. or higher, preferably 35 ° C. or higher, more preferably 40 ° C. or higher, still more preferably 45 ° C. or higher. When Tg is less than 30 ° C., the effect of improving the surface hardness of the laminated building material cannot be obtained. That is, if the Tg of the amorphous component is too low, there is a possibility that the hardness at normal temperature cannot be obtained. However, although the hardness of the adhesive is lowered when heated exceeding the non-crystalline Tg, the influence is relatively small as compared with the case where the melting point of the crystalline component is exceeded. Also, the content of the non-crystalline component can be made smaller as the Tg is higher for the same reason as the crystalline component.

  The reactive hot melt adhesive used in the present invention is prepolymer (in order to satisfy various properties as an adhesive (adhesiveness, creep resistance, etc.), hardness at the time of cooling and solidification and after moisture curing, etc. at the same time. As A), a prepolymer having both a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a Tg of 30 ° C. or higher in the same molecule may be used, or a prepolymer having both components as main skeletons. What mixed the polymer suitably may be used, or either may be used independently.

  In addition, the reactive hot melt adhesive used in the present invention may be added with a prepolymer other than the prepolymer (A), and in order to improve adhesiveness, fluidity, and adhesive properties, Various additives such as various plasticizers and catalysts may be added. However, when adding a component other than the prepolymer (A), care must be taken not to reduce the hardness of the adhesive itself more than necessary.

A specific example of the prepolymer (A) is typically one having a polyester skeleton composed of a dibasic acid and a polyol. That is, a crystalline or non-crystalline polyester skeleton can be obtained by using a combination of dibasic acid and polyol as appropriate.
In addition, examples of the dibasic acid include adipic acid, sebacic acid, dodecanedioic acid, phthalic acid, isophthalic acid, terephthalic acid, and the like. Examples of the polyol include ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, Neopentyl glycol and the like can be mentioned.
Specifically, for example, a crystalline polyester having a melting point of 55 to 65 ° C. is obtained by reacting adipic acid and hexanediol, and adipic acid and isophthalic acid are appropriately reacted with ethylene glycol and neopentyl glycol. Thus, an amorphous polyester having a Tg of about 50 ° C. can be obtained.

  The melting point of the crystalline polyester largely depends on the type of dibasic acid and polyol selected, but can be controlled to some extent by the molecular weight. The Tg of the non-crystalline polyester can also be controlled by the type of dibasic acid and polyol to be combined, the blending ratio, and the molecular weight.

And a prepolymer (A) can be obtained by reacting a diisocyanate compound etc. with respect to the compound (polyester polyol) which made the both terminal of these polyester frame | skeletons into a hydroxyl group, and control of melting | fusing point or a glass transition point is possible. Therefore, as in the building material of claim 3, the main chain is substantially a polyester skeleton, and the compound having a plurality of isocyanate groups in the hydroxyl group of the compound (B) having an average number of hydroxyl groups exceeding 1. What added (C) is suitable.
Further, both ends of the prepolymer (A) are not particularly limited as long as they have reactivity, but for example, they can be isocyanate groups, alkoxysilyl groups, epoxy groups, and the like.

Although it does not specifically limit as said compound (B), In order to express more heat resistance and durability, the average number of the hydroxyl groups which a polyester frame | skeleton has is preferably 2 or more, and both ends are substantially hydroxyl groups. Some are easily available industrially.
On the other hand, the compound (C) is not particularly limited, and various compounds can be used. Generally, MDI (4,4-diphenylmethane diisocyanate), TDI (tolylene diisocyanate), HDI (1, 6-hexamethylene diisocyanate) is easily available.
For example, when MDI which is a diisocyanate compound is added to both ends of a compound (B) whose both ends are hydroxyl groups, the prepolymer (A) in which both ends are substantially isocyanate groups and both ends are isocyanate groups. Can be obtained. When both ends are isocyanate groups, the reaction is caused by moisture in the atmosphere, and the prepolymer (A) is added to increase the molecular weight, whereby the reactive hot melt adhesive can be cured. The cured product is not easily melted by heat, and the heat resistance and durability are remarkably improved.

  As the crystalline polyester constituting the prepolymer (A), those having a molecular weight of 1000 or more are preferable, but a molecular weight of 1500 to 9000 is more preferable in order to achieve a good balance between melt viscosity, adhesiveness, and long open time, A molecular weight of 1500 to 7500 is more preferable, and a molecular weight of 2000 to 4500 is particularly preferable. That is, if the molecular weight is too low, recrystallization hardly occurs, and after cooling from the molten state, it becomes difficult to cool and solidify even after a long time, and the initial adhesive strength of the surface material cannot be obtained, or the pressing process Problems such as loss of the surface smoothness developed in the above are likely to occur. Moreover, there is a possibility that the creep property is also lowered, and there is a possibility that problems such as initial adhesiveness, surface material floating, peeling, and surface smoothness are reduced as described above. On the other hand, if the molecular weight is too high, the melt viscosity increases, so the workability deteriorates, the applicability and workability decrease, and stringing occurs to contaminate the surface material and wettability to the adherend. There is a possibility that the adhesive strength is reduced due to the decrease in (normal state).

  In addition, the prepolymer (A) having a crystalline polyester having a melting point of 50 ° C. or higher and an amorphous polyester having a Tg of 30 ° C. or higher in the skeleton is not particularly limited, and includes, for example, butanediol and adipic acid. Tg of 30 ° C. or more comprising crystalline polyester having both ends of the polyester having a melting point of 50 ° C. or higher, terephthalic acid and isophthalic acid as acid components, and ethylene glycol and neopentyl glycol as diol components It can be obtained by mixing with a non-crystalline polyester having hydroxyl groups at both ends and partially crosslinking with a crosslinking agent such as diisocyanate.

The Tg of the polyester constituting the non-crystalline skeleton is preferably 30 ° C. or higher and 120 ° C. or lower, more preferably 35 ° C. or higher and 100 ° C. or lower, in view of being melt mixed with other raw materials in the adhesive manufacturing process. 40 ° C. or more and 80 ° C. or less is particularly preferable.
Furthermore, when the target building material is a flooring and is used for an application involving heating such as floor heating, the Tg of the polyester constituting the amorphous skeleton portion is desirably 50 ° C. or higher. More preferably, it is 60 ° C. or higher, and particularly preferably 70 ° C. or higher.

  In addition to the prepolymer (A), a thermoplastic resin and / or a tackifying resin can be added to the reactive hot melt adhesive used in the present invention for the purpose of improving initial tack physical properties. is there.

  Although it does not specifically limit as said thermoplastic resin, For example, polycaprolactone, polyesters, a polyurethane, a styrene block polymer, etc. whose molecular weight is about 20000-100,000 can be used.

  As these thermoplastic resins, it is preferable to select those having a relatively high molecular weight. However, if the addition amount is increased, the melt viscosity of the resulting adhesive increases and the workability decreases, so the addition amount is 1. -15 wt% is preferable, and 2-10 wt% is more preferable.

  The tackifying resin is not particularly limited as long as it is compatible or partially compatible with the urethane prepolymer. For example, petroleum resins such as rosin ester, terpene resin, styrene resin, Alternatively, a copolymer thereof, a part of these resins, or a completely hydrogenated resin can be used.

  As these tackifying resins, since the molecular weight is relatively small, the addition amount is preferably 3 to 25% by weight, and more preferably 4 to 15% by weight. Here, if the amount of addition of the tackifying resin having a high Tg is too large, recrystallization of the prepolymer is hindered and it becomes difficult to make it non-tacky.

  Moreover, as Tg of the said tackifying resin, the range of 30 to 80 degreeC is preferable, and the range of 40 to 70 degreeC is more preferable. The softening temperature of the tackifying resin is generally about 90 ° C. or higher and 120 ° C. or lower although it depends on the chemical composition of the resin.

  In the case of the reactive hot melt adhesive used in the present invention, in order to adjust the melt viscosity of the resulting adhesive to a low level, the effects of the present invention can be achieved by using a urethane prepolymer that is liquid at room temperature, liquid and solid plasticizers, and the like. You may add suitably in the range which is not lost. In addition, for example, a pH adjuster, a filler, an antioxidant, an anti-aging agent, an antifungal agent, a colorant, a thickener, an antifoaming agent, a flame retardant, and a fragrance are added as necessary. It doesn't matter.

The wood substrate used in the present invention is not particularly limited. For example, solid wood, plywood, particle board (hereinafter referred to as “perch material”), medium density fiber board (hereinafter referred to as “MDF”). ), And laminated wood. Among them, the surface hardness is originally low and the porous material has a higher improvement effect. Therefore, in the environment of 20 ° C. and 60% Rh as in the building material of claim 4 Using a DuPont impact tester on a wood substrate left for 24 hours or more in an environment of 20 ° C and 60% Rh, a weight with a weight of 500 g and a tip diameter of 6.3 mm is dropped from a height of 300 mm. It is preferable that the depth of the dents formed at the time is 0.5 mm or more on average.
The lower the surface hardness, the greater the effect that can be obtained. Therefore, the average depth of recesses is more preferably 0.7 mm or more, and still more preferably 0.9 mm or more.
However, for example, when a material having a high surface hardness and a high surface smoothness such as a MDF or a perch material having a high density or a high resin content is used as a wooden substrate, the effect is reduced to some extent. Since the above effect can be obtained, it is possible to use it with a smaller dent amount.
In addition, for the above reasons, solid wood and plywood can be expected to have an effect on hardwoods, southern seawood, etc., rather than hard conifers such as cedar and pine.

  As a sheet material imparting designability used in the present invention (hereinafter referred to as “design sheet”), a decorative sheet such as paper, non-woven fabric, or synthetic resin sheet is subjected to decorative processing such as painting, pattern printing, and embossing on uneven patterns. Although well-known things, such as those applied, can be selected as appropriate, it is preferable to use a relatively thin paper-based material having a basis weight of 50 g or less (more preferably 40 g or less) per square meter as in the building material of claim 5. . That is, the effect of the present invention can be expected more by using a thin material that is affected by the unevenness of the surface of the wooden substrate.

  When manufacturing the building material of this invention, you may apply | coat an adhesive agent to any of a wooden base material and a design sheet. Further, the application method is not particularly limited as long as it can be applied in a planar shape. Further, in the case where hot pressing is performed at the time of bonding, the adhesive may be melted by heat at the time of hot pressing and may flow along with the pressing so that the adhesive spreads in a substantially continuous plane.

  The method for laminating the wooden substrate and the design sheet is not particularly limited, but it is preferable to perform hot pressing as in the production method of the present invention. That is, by performing hot pressing, the surface hardness can be further improved and the adhesion between the design sheet and the wooden substrate can be improved, and high smoothness can be expressed.

The press temperature needs to be higher than the softening temperature of the adhesive in order to sufficiently soften the adhesive and enter the fine irregularities of the wooden substrate and the design sheet. Effectively, it is better to perform hot pressing at a temperature higher than the softening temperature of the adhesive by about 10 ° C., more preferably 15 ° C. or more, and even more preferably 20 ° C. or more. However, if the press temperature is higher than necessary, the same problems as in the case where the press time described later is long occur, and the surface smoothness may be lowered because the cooling shrinkage of the adhesive becomes larger than necessary. Therefore, the upper limit of the press temperature is desirably 150 ° C. or less. As will be described later, depending on the material, it may be effective to press at a lower temperature. Although the pressing time depends on the temperature and the amount of heat of the member, it is generally preferable to perform the pressing for 15 seconds or longer. More effectively, it is 25 seconds or more, more preferably 30 seconds or more. However, if the hot press time is longer than necessary, the reactive hot-melt adhesive will sag and adversely affect the adhesiveness and surface smoothness, so it is necessary to adjust accordingly. In addition, if the wooden substrate itself is heated too much, it takes more time than necessary for the cooling time, and problems such as a long process time are likely to occur.
Moreover, since woody materials and paper-like materials contain a considerable amount of water, it may be more effective to press at a temperature of 100 ° C. or lower. Moreover, you may provide a cold press process after hot pressing as needed.

  Moreover, you may make it provide the protective layer etc. further on the surface of the design sheet | seat in the building material of this invention. For example, you may use the sheet | seat material which gave further transparent coating from the design sheet | seat, laminated | stacked a transparent film, or already laminated | stacked the surface layer.

  As described above, the building material according to the present invention has the prepolymer (A) in which the adhesive layer has at least one of a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a Tg of 30 ° C. or higher in the skeleton. Because it is formed by a reactive hot melt adhesive contained in the ingredients, even if a wooden substrate with a defective surface or insufficient strength is used, it is excellent in strength without using a putty material The surface shape is excellent and the heat resistance is excellent.

  In other words, since the 100% solid adhesive component is used, the surface of the wood substrate can be filled to some extent with the scratches and wormholes. Smoothness is increased and design properties are improved. In addition, since the prepolymer reacts and the adhesive is cured after pasting, even when using a sheet material with little elongation such as paper quality, the amount of dent deformation is small and the sheet material adheres firmly to the sheet material. Is difficult to tear, and even if the plate material undergoes impact deformation, the design is not greatly impaired.

  In the method for producing a building material according to the present invention, at least one of a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a Tg of 30 ° C. or higher is provided between the wooden substrate and the sheet material imparting designability. Since it includes a step of hot pressing the wood base material and the sheet material imparting designability in a state of interposing the reactive hot melt adhesive containing the prepolymer (A) in the component, further The surface hardness can be improved and the adhesion between the design sheet and the wooden substrate can be improved, and high smoothness can be expressed.

Hereinafter, embodiments of a building material and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows one embodiment of a method for manufacturing a building material according to the present invention.

  As shown in FIG. 1, the manufacturing method of this building material 1 conveys the wooden base material 2 made into the plate shape of desired length to the place of the adhesive agent coating apparatus 3, and one side of the wooden base material 2 with a roll coater. A reactive hot melt adhesive 4 containing 40% by weight or more of a prepolymer (A) having at least one of a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a Tg of 30 ° C. or higher in the skeleton. Apply in molten state.

Next, a continuous belt-shaped design sheet 5 is continuously supplied onto the applied reactive hot melt adhesive 4 and pressed by a pressing roller 6, and then the design sheet 5 is aligned with the wood substrate 2. And cut.
Then, if necessary, hot pressing is performed by the hot press device 7 and further pressing is performed by the cold and hot press device 8, and then the reactive hot melt adhesive 4 is cured and cured by moisture in the atmosphere.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the wooden base material has a plate shape, but it may be a three-dimensional one. Further, the design sheet may be affixed to the wood base material in a batch manner instead of continuously as described above.

  Hereinafter, specific examples of the present invention will be described in detail in comparison with comparative examples. The present invention is not limited to the following examples.

(Examples 1-9, Comparative Examples 1-4)
Woody base materials A and B, adhesives A to D, a design sheet, and a crosslinking agent shown below were prepared.
-Wood substrate A: 7-layer plywood, thickness 12mm,
Indentation value average 0.6 mm or more by DuPont impact test ・ Wood base material B: 5-layer plywood, thickness 12 mm,
The average dent value by the DuPont impact test is 0.9 mm or more. The above dent value average is the atmosphere at the time of measurement after leaving the test pieces of the wood base materials A and B in an environment of 20 ° C. and 60% Rh for 24 hours or more. Similarly, at 20 ° C. and 60% Rh, a drop distance of 300 mm, a drop weight of 500 g, and a hitting core diameter of 6.3 mm are used, and the measurement is performed by using a digital display caliper capable of measuring up to 1/100 mm and n = 5. Measured and averaged.

-Adhesive A: Modified vinyl acetate emulsion adhesive manufactured by Sekisui Fuller
Product name Sdyne 5800 (43% non-volatile content)
Adhesives B, C, and D: The following raw materials A to D and the cross-linking agent were adjusted at the blending ratios shown in Table 1 below. As a specific adjustment method, components other than the crosslinking agent are heated, melted and mixed, dehydrated under reduced pressure, and then the crosslinking agent is measured and added. Immediately after the addition, the mixture was immediately purged with nitrogen and stirred and mixed at 100 ° C. for 2 hours to react and add a crosslinking agent to both ends of the diol to produce a urethane prepolymer to obtain a reactive hot melt adhesive.
Raw material A: polyester having a molecular weight of 3000 consisting of butanediol and adipic acid
Both ends are OH.
Raw material B: Polyester diol having a Tg of 34 ° C. comprising terephthalic acid and isophthalic acid as acid components and ethylene glycol and neopentyl glycol as diol components.
Raw material C: Obtained by reacting 125 M of isonate at both ends of a polybutadiene-diol having a molecular weight of 2000.
Raw material D: Dainippon Ink Polyester resin ODX-2547
・ Crosslinking agent: Diisocyanate trade name isonate 125M manufactured by Dow Chemical Company
・ Design sheet: decorative paper with a weight of 50 g / m ²

Next, a building material sample is prepared under the conditions shown in Tables 2 to 4, and the average dent value by the DuPont-type impact test on the design sheet side of the obtained building material sample is obtained in the same manner as the wooden base material. In order to confirm the adhesion between the sheet and the wooden substrate, a 2 mm square cross-cut test was performed, and evaluation was performed with the number of grids in which no peeling was observed in 100 squares. Indicated. Moreover, the surface state of the surface of the obtained building material sample on the side of the design sheet was examined visually, and the results are also shown in Tables 2 to 4.
In addition, the roll coater was used for application | coating to the woody base material or design sheet | seat of an adhesive agent.
In addition, the evaluation of the surface condition is that there are very fine irregularities, but the one that looks almost mirror-like is ◯, the one that is almost flat but slightly irregular is △, the irregularities of wood grain and defects appear on the surface What was felt to be was marked with x.

  From the above Tables 2 to 4, as in the building material of the present invention, a prepolymer having a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a Tg of 30 ° C. or higher as an adhesive in the skeleton (A It is well understood that the use of a reactive hot melt adhesive containing) can improve the surface strength. In addition, it is well understood that the design sheet and the wooden base material can be more reliably bonded by hot pressing at the time of bonding.

It is explanatory drawing which represents typically one embodiment of the manufacturing method of the building material concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Building material 2 Woody base material 4 Reactive hot-melt-adhesive 5 Design sheet (Sheet material which provides design properties)

Claims (6)

  A building material in which a sheet material that imparts designability is bonded to the surface of a wooden substrate through an adhesive layer, the adhesive layer having a crystalline component having a melting point of 50 ° C or higher and a glass transition point of 30 ° C or higher A building material characterized in that it is formed of a reactive hot melt adhesive containing a prepolymer (A) having at least one of an amorphous component in the skeleton.   The building material according to claim 1, wherein the reactive hot-melt adhesive contains 40% by weight or more of the prepolymer (A).   The prepolymer (A) is obtained by adding a compound (C) having a plurality of isocyanate groups to the hydroxyl group of a compound (B) having a main chain substantially having a polyester skeleton and having an average number of hydroxyl groups exceeding 1. The building material according to claim 1 or claim 2.   The impact strength of a wooden substrate is 20 g and 60% Rh. On a wooden substrate left for 24 hours or more in a 20 ° C. and 60% Rh environment, using a DuPont impact tester, the weight is 500 g. The building material according to any one of claims 1 to 3, wherein a dent depth formed when a weight having a core tip diameter of 6.3 mm is dropped from a height of 300 mm is 0.5 mm or more on average. .   The building material according to any one of claims 1 to 4, wherein the sheet material imparting design properties is a paper-based material having a weight of 50 g or less per square meter.   Prepolymer (A) having in its skeleton at least one of a crystalline component having a melting point of 50 ° C. or higher and an amorphous component having a glass transition point of 30 ° C. or higher between a wooden substrate and a sheet material imparting design properties The building material in any one of Claims 1-5 provided with the process of heat-pressing a wooden base material and the sheet | seat material which provides designability in the state in which the reactive hot-melt-adhesive agent containing this was interposed. Manufacturing method.

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