JP2021059110A - Manufacturing method of laminated wood - Google Patents

Abstract

To improve wettability of an aqueous adhesive coated on one surface of a lamina to a bonding surface of another lamina, thereby enhancing the adhesion property of the aqueous adhesive.SOLUTION: There is provided a manufacturing method of laminated wood 10, the method comprising an adhesive coating step of coating an aqueous adhesive 12 on respective surfaces on one side of a plurality of laminae 11 excluding an uppermost stage or lowermost stage lamina 11 among the plurality of laminae 11; and a laminating/clamping step of laminating/clamping the plurality of laminae 11 to manufacture the laminated wood in such a manner that a surface on which the aqueous adhesive 12 of a lamina 11 is coated, and another surface on which no aqueous adhesive 12 of the other lamina 11 is coated come into contact with each other. The method further comprises a water coating step of coating water 13 in a coating amount of 5 g/m2 to 25 g/m2 on other surfaces of the plurality of laminae 11 excluding a lowermost stage or uppermost stage lamina 11 among the plurality of laminae 11 before the adhesive coating step, or between the adhesive coating step and the laminating/clamping step.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a laminated lumber formed by laminating and adhering a plurality of laminas made of a sawn plate or a piece of a small square timber.

Conventionally, a method for producing a wood composite material in which an adhesive is applied to an adhesive surface between a wood molding material and wood, the bonded surfaces are overlapped with each other, pressurized and heated at a high frequency to bond the wood molding material and wood is disclosed. (See, for example, Patent Document 1 (claims 1 and 2, paragraphs [0013], [0014], FIG. 1)). In this method for producing a wood composite material, an adhesive is applied to one of the adhesive surfaces of the wood molding material or wood, and an aqueous electrolyte solution is applied to the other adhesive surface. The aqueous electrolyte solution is a saline solution.

In the method for producing a wood composite material configured in this way, an adhesive is applied to one of the adhesive surfaces of the wood molding material and wood, and an aqueous electrolyte solution is applied to the other adhesive surface, which is sufficient for the adhesive surface. A large amount of electrolyte can be supplied, and the amount of heat generated during high-frequency heating can be made sufficient. As a result, the wood molding material and the wood can be bonded in a short time, and the productivity of the wood composite material can be improved. Further, since the aqueous electrolyte solution is a saline solution, the aqueous electrolyte solution can be easily prepared, and a saturated aqueous solution can be easily prepared.

Further, a method for manufacturing a laminated wood that can avoid a poor adhesion phenomenon due to drying of an adhesive in a manufacturing process of the laminated wood in a high temperature working environment such as summer is disclosed (for example, Patent Document 2 (Claim 1). , Paragraph [0009], Fig. 1).). In this method for producing laminated wood, first, a water-based adhesive is applied to the surface of the lamina to form an adhesive surface. Next, a certain amount of water mist having a fine particle size per surface area of the adhesive surface is uniformly sprayed to moisten the adhesive surface. Next, another lamina that has not been coated with the water-based adhesive is superposed on the wet adhesive surface to form a lamina laminate. Further, the lamina laminate is pressed at room temperature.

In the method for producing the laminated material configured in this way, a certain amount of water mist is sprayed on the water-based adhesive coated surface immediately after the water-based adhesive is applied to the lamina adhesive surface even in a high temperature atmosphere such as summer. As a result, the adhesive surface is moistened, and at the same time, the temperature and relative humidity of the environment around the laminar after application of the adhesive and the environment in the laminating process are appropriately controlled. Even if an aqueous adhesive with a non-volatile component concentration of 50 to 80% by mass, which is used at the temperature of the atmosphere in winter, is used as it is without preparation, it has good adhesive strength without causing poor adhesion due to the dryout phenomenon. Glue is now available.

JP-A-2010-76240 Japanese Unexamined Patent Publication No. 2015-71252

However, in the method for producing a wood composite material shown in Patent Document 1, when an aqueous electrolyte solution is supplied to an adhesive surface coated with an adhesive, the reaction by high-frequency heating becomes faster, but the adhesive interface is peeled off and the adhesiveness is improved. There was a problem that it decreased. In addition, since saline solution is used as the aqueous electrolyte solution, rust is generated in the wood composite manufacturing equipment, the adhesive layer of the wood composite becomes poor in water resistance, and peeling at the bonding interface increases, resulting in adhesiveness. There was also a problem that the amount was further reduced.

On the other hand, the method for producing laminated wood shown in Patent Document 2 improves the adhesive performance, although the adhesive surface can be moistened by spraying water mist on the adhesive surface to avoid poor adhesion due to drying of the adhesive. Adhesive performance was insufficient for hard-adhesive wood such as glulam.

A first object of the present invention is to improve the adhesiveness of the water-based adhesive applied to one surface of the laminar to the surface to be adhered to the other lamina, thereby improving the adhesiveness of the water-based adhesive. The purpose is to provide a method for producing laminated wood. A second object of the present invention is to provide a method for producing laminated wood capable of improving the adhesive performance of poorly adhered wood such as larch.

As shown in FIG. 1, the first aspect of the present invention is to apply a water-based adhesive 12 to one surface of a plurality of laminars 11 excluding the uppermost or lowest laminars 11 among the plurality of laminars 11. By laminating and pressing a plurality of lamina 11 so that the surface coated with the water-based adhesive 12 of the lamina 11 and the surface not coated with the water-based adhesive 12 of another lamina 11 are in contact with each other in the agent coating step. In the method for producing laminated wood 10 including a laminated laminated material manufacturing step for producing laminated wood, a plurality of laminars 11 are used before the adhesive applying step or between the adhesive applying step and the laminated pressing step. out on the other surface of the plurality of laminae 11 with the exception of the lowermost or uppermost lamina 11, and further comprising a water application step of applying each of water 13 at a coverage of from 5g / m ² ~25g / m ² To do.

The second aspect of the present invention is an invention based on the first aspect, further as shown in FIG. 1, wherein the coating amount of the water 13 is 10g / m ² ~20g / m ² ..

In the method for producing laminated wood according to the first aspect of the present invention, the lowermost or uppermost laminar among a plurality of laminars is applied before the adhesive application step or between the adhesive application step and the stacking compression step. water on the other surface of the plurality of laminae, so applying each water at a coverage of from ^{5g / m 2 ~25g / m 2} , water was applied to the other surface of the lamina, were applied to one side of the lamina, excluding Contact the adhesive. As a result, the wettability of the water-based adhesive to the surface to be adhered (water-coated surface) is improved, so that the adhesiveness of the water-based adhesive can be improved. Further, even if the wood is difficult to adhere to, such as larch, which cannot sufficiently exhibit the adhesive performance with the conventional adhesive, the adhesive performance can be improved.

It is a figure which represented typically the procedure for manufacturing the laminated wood of 1st Embodiment of this invention. It is a perspective view of the laminated wood of the Example and the comparative example processed according to the block shear test test piece of the structural laminated wood specified in the Japanese Agricultural Standard.

Next, a mode for carrying out the present invention will be described with reference to the drawings. As shown in FIG. 1, the laminated lumber 10 is formed by laminating and adhering a plurality of sawn timbers or small square lumbers (lamina 11) having a thickness of about 2 cm with their fiber directions parallel to each other. Such laminated wood 10 can be used for pillars, beams, girders, stairs, flooring, etc. of wooden houses. The thickness, width, and length of the laminar 11 described in this embodiment are about 2 cm, about 11 cm, and several meters, respectively.

In this embodiment, an adhesive application step of applying the water-based adhesive 12 to one surface of a plurality of laminas 11 and a laminated compression step of laminating and compressing these laminas 11 are included, and the adhesive is applied. Prior to the step, water 13 is applied to the other surface of the plurality of laminars 11 to produce laminated wood 10. Specifically, in order to manufacture the laminated wood 10, first, as shown in FIG. 1A, one surface (lower surface) of the plurality of laminars 11 excluding the lowermost laminar 11 among the plurality of laminars 11. ) Is coated with water 13. The coating amount of the water 13 is ^{5g / m 2 ~25g / m 2} , is preferably ^{10g / m 2 ~20g / m 2} . Here, The reason for limiting the application amount of the water 13 within the range of 5g / m ² ~25g / m ² are not observed improvement in adhesion performance is less than 5 g / m ^2, the adhesive exceeds 25 g / m ² This is because the performance is reduced.

Water 13 is applied to one surface of the laminar 11, and in this embodiment, as a method of applying the water 13 to the lower surface of the lamina 11, the water 13 is applied to the outer peripheral surface of the lower roller of the pair of upper and lower rollers that convey the lamina. Examples include a roll coater coating method in which water is transferred to the lower surface of the lamina, and a mist spraying method in which water is made into a mist and sprayed on the lower surface of the lamina. In this embodiment, water 13 is applied to the lower surface of the laminar 11 by the roll coater coating method. Specifically, as shown in FIG. 1A, the lower portion of the watering roller 16 is immersed in the water 13 stored in the container 14, and the holding roller 17 is provided above the watering roller 16 with the laminar 11 sandwiched between them. In this state, by rotating the watering roller 16 and the pressing roller 17 in the directions of the solid arrows, the water 13 in the container 14 adheres to the outer peripheral surface of the watering roller 16, and the adhered water 13 is the lamina 11. It is applied to the bottom surface.

Next, as shown in FIG. 1 (b), the water-based adhesive 12 is applied to the other surface (upper surface) of the plurality of laminas 11 excluding the lowermost lamina 11 among the plurality of laminas 11. As the water-based adhesive 12, various known ones can be used without particular limitation. As the water-based adhesive 12, for example, an emulsion-type adhesive in which synthetic resin polymers such as vinyl acetate resin emulsion, acrylic resin emulsion, acrylic / styrene resin emulsion, and styrene / butadiene resin latex are dispersed in water, or highly water-soluble adhesive. A main agent composed of one or more of molecules and an aqueous emulsion and a curing agent composed of an isocyanate compound such as 4,4-diphenylmethane diisocyanate (monomeric MDI) or polymethylene polyphenyl isocyanate (polymeric MDI) are blended. Examples thereof include water-based polymer isocyanate-based adhesives. The concentration of the non-volatile component of the water-based adhesive 12 is preferably 50% by mass to 80% by mass.

As a method of applying the water-based adhesive 12, a roll coater coating method suitable for coating on a flat material, a spray coating method suitable for coating on a curved surface or a complicated shape, or a slit-shaped die called a T die is used. Examples thereof include a coating method suitable for a relatively thin material in which the adhesive is extruded into a film and applied. In this embodiment, a method of applying the water-based adhesive 12 to the upper surface of the laminar 11 by the roll coater coating method will be described. The roll coater is in contact with a conveyor (not shown) that conveys the laminar 11, a pair of large-diameter rollers 18 and 18 that rotate while sandwiching the lamina 11, and the upper large-diameter roller 18 of the large-diameter rollers 18 and 18. It is provided with a small diameter roller 19 that rotates. Then, the water-based adhesive 12 is stored in a recess between the small-diameter roller 19 and the upper large-diameter roller 18, and the water-based adhesive 12 stored in the recess is taken up by the outer peripheral surface of the upper large-diameter roller 18. After that, it is applied to the upper surface of the lamina 11. Further, by rotating a pair of large-diameter rollers 18 and 18 to move the long laminar 11 at a rate of 50 m / min to 100 m / min, a coating amount of 150 g / m ^{2 to} 300 g / m is applied to the upper surface of the laminar 11. ^{In step 2} , a uniform coating film of the water-based adhesive 12 is formed.

Next, as shown in FIG. 1 (c), one surface (upper surface) coated with the water-based adhesive 12 of Lamina 11 and the other surface (lower surface) coated with water 13 of another Lamina 11 are in contact with each other. A plurality of lamina 12 are laminated on the laminated body 21 to prepare a laminated body 21. The laminar 11 located at the uppermost stage of the laminated body 21 uses the lamina 11 to which the water-based adhesive 12 is not applied to the upper surface, and the lamina 11 located at the lowermost stage does not have the water 13 coated to the lower surface. 11 is used. The number of laminated lamina 11 can be from 2 to about 100 depending on the thickness of the laminar 11 to be pressed and the capacity of the pressing machine.

Further, as shown in FIG. 1D, the laminated body 21 in which a plurality of laminas 11 are laminated is pressed to produce the laminated wood 10. Specifically, the laminated wood 10 manufactured by mounting the laminated body 21 on a pressing machine and pressing the laminated body 21 at a pressure of 0.8 MPa to 1.2 MPa for 20 to 40 minutes is placed in the atmosphere. Leave it for 3 to 6 days to cure.

In the method for producing the laminated wood 10 configured in this way, one surface (upper surface) coated with the water-based adhesive 12 of Lamina 11 and the other surface (lower surface) coated with water 13 of another Lamina 11 are in contact with each other. Since the plurality of laminas 11 are laminated as described above, the water-based adhesive 12 applied to one surface of the lamina 11 comes into contact with the water 13 applied to the other surface of the other lamina 11. As a result, the wettability of the water-based adhesive 12 to the surface to be adhered (water-coated surface) is improved, so that the adhesiveness of the water-based adhesive 12 can be improved.

In the above embodiment, the adhesive coating step includes an adhesive coating step of applying a water-based adhesive to one surface of a plurality of laminas, and a laminated squeezing step of laminating and squeezing these laminas 11. Prior to the process, water was applied to the other surface of the plurality of laminars 11 to produce laminated wood, but water was applied to the other surface of the plurality of laminars 11 between the adhesive application step and the laminating compaction step. It may be applied to produce laminated wood.

Next, examples of the present invention will be described in detail together with comparative examples.

<Example 1>
As shown in FIG. 1, four red woods having a thickness, width and length of 2.7 cm, 11.0 cm and 300 cm, respectively, were prepared as the laminar 11. In addition, 15 parts by mass of Polymeric MDI (AX-500: Polymethylene polyphenyl polyisocyanate, manufactured by Koyo Sangyo Co., Ltd.) is added to 100 parts by mass of an aqueous emulsion type adhesive (KR-134, non-volatile component concentration 60%). Aqueous polymer isocyanate-based adhesive (water-based adhesive) 12 was prepared by partially mixing. Then, first, water 13 was applied to the lower surface of the lamina 11 by a roll coater application method (FIG. 1 (a)). At this time, the amount of water 13 applied to the lower surface of the laminar 11 was 5.2 g / m ² . Next, the aqueous polymer isocyanate-based adhesive (water-based adhesive) 12 was applied to the upper surface of the separate lamina 11 with a roll coater (FIG. 1 (b)). At this time, the coating amount of the aqueous polymer isocyanate-based adhesive (water-based adhesive) 12 was 250 g / m ² . Next, the above four lamina 11 are laminated to prepare a laminated body 21 (FIG. 1 (c)), and a pressure of 1.0 MPa is applied to the laminated body 21 for 30 minutes to compress the laminated wood 10. Manufactured (FIG. 1 (d)). Further, this laminated wood 10 was cured for 3 days. This laminated wood 10 was designated as Example 1.

<Examples 2 to 6 and Comparative Examples 1 to 4>
As shown in Table 1, the laminated woods of Examples 2 to 6 and Comparative Examples 1 to 4 were produced in the same manner as in Example 1 except that the amount of lamina tree species or water applied was changed. did.

<Comparative example 5>
As shown in Table 1, the laminated wood of Comparative Example 5 was produced in the same manner as in Example 1 except that a saline solution having a concentration of 20% was applied instead of water.

<Comparative Example 6>
As shown in Table 1, the laminated wood of Comparative Example 6 was produced in the same manner as in Example 1 except that water mist was sprayed on the coated surface of the adhesive.

<Comparative Example 7>
As shown in Table 1, the laminated wood of Comparative Example 7 was the same as that of Example 1 except that the lamina tree species was changed to larch (difficult-to-adhere wood) and water mist was sprayed on the surface to which the adhesive was applied. And manufactured laminated lumber.

<Comparative test 1 and evaluation>
The block shear boiling repeated test was performed on the test pieces of the laminated wood of Examples 1 to 6 and Comparative Examples 1 to 7. Specifically, first, four test pieces were prepared from each laminated wood as test pieces as shown in FIG. Next, the test piece was immersed in boiling water for 4 hours, dried in air at 60 ± 3 ° C. for 20 hours, further immersed in boiling water for 4 hours, then immersed in boiling water until cooled, and kept wet. A shear test was performed in this state. The maximum load until the test piece broke was measured by a testing machine, and the strength was obtained by dividing by the measured adhesive area, and the percentage of the ruptured area with respect to the shear area was read in 10% increments to obtain the xylem fracture rate. The results are shown in Table 1.

In the columns of adhesive performance strength and wood part breaking rate in Table 1, when the type of lamina (tree type) is redwood, the strength is ^{improved by 2.5} N / mm 2 or more and the wood part is improved as compared with Comparative Example 1. what breakage rate was 50% or more was judged as "excellent", strength to Comparative example 1 is improved less than 1.0 N / mm ² or more 2.5 N / mm ^2, and wood breakage rate is 30 % Or more was judged as "good", and the strength was ^{improved by 1.0 N / mm 2} or more and the wood fracture rate was not improved, or the strength was not improved as compared with Comparative Example 1. Those having a wood part breaking rate of 30% or more were judged as "possible", and those in which neither the strength nor the wood part breaking rate was improved as compared with Comparative Example 1, or the improvement in strength was 1 N / mm ² Those having less than 30% and the wood part breaking rate were less than 30% were judged as "impossible".

Further, in the columns of the strength of the adhesive performance and the breaking rate of the wood part in Table 1, when the type of lamina (tree type) is Karamatsu, the strength is ^{improved by 1.0 N / mm 2} or more as compared with Comparative Example 2, and the wood those parts breakage rate was 50% or more was judged as "excellent", strength to Comparative example 2 is improved less than 0.5 N / mm ² or more 1.0 N / mm ^2, and wood fracture rate If it was 30% or more, it was judged as "good", and the strength was ^{improved by 0.5 N / mm 2} or more and the wood fracture rate was not improved, or the strength was not improved as compared with Comparative Example 2. And the one having a wood part breaking rate of 30% or more was judged as "OK", and the one in which neither the strength nor the wood part breaking rate was improved as compared with Comparative Example 2, or the improvement in strength was 0.5N. / mm ² below and xylem breakage rate is determined what was less than 30% as "impossible".

<Type of lamina (tree species): Redwood>
As is clear from Table 1, the laminated lumber of Comparative Example 1 in which water was not applied to the lower surface of the lamina had low adhesive performance strength and xylem breaking rate of 3.4 N / mm ² and 22%, respectively, and thus adhered. The judgment of performance was "impossible". Further, in the laminated wood of Comparative Example 3 in which the amount of water applied was 2.1 g / m ² and less than the appropriate range (5 g / m ^{2 to} 25 g / m ² ), the strength of the adhesive performance and the breaking rate of the wood part were 3 respectively. Since it was as low as 0.8 N / mm ² and 28%, the judgment of the adhesive performance was "impossible". Further, in the laminated wood coating amount of water is 30.8 g / m ² within an appropriate range ^{(5g / m 2 ~25g / m} 2) more than Comparative Example 4, the strength and xylem breakage rate of the adhesive performance, each 3 Since it was as low as .9 N / mm ² and 25%, the judgment of the adhesive performance was "impossible".

For these, the laminated wood of Examples 1 to 5 The coating amount of the water is in an appropriate range with ^{5g / m 2 ~25g / m 2} , the strength and xylem breakage rate of the adhesive performance, respectively 4.8 N / Since it was as high as mm ^{2 to} 6.3 N / mm ² and 34% to 58%, the judgment of the adhesive performance was "excellent" or "good".

In the laminated wood of Comparative Example 5 in which 15.3 g / m ^{2 of} saline solution was applied instead of water, the strength of the adhesive performance and the breaking rate of the wood part were ^{as low as 1.3 N / mm 2} and 0%, respectively, so that they were adhered. The judgment of performance was "impossible".

Further, although the spray amount of water mist ^{was within an appropriate range of 15.5 g / m 2} , the laminated wood of Comparative Example 6 in which water mist was sprayed on the upper surface of the lamina coated with the water-based adhesive had an adhesive performance. Although the strength was as ^{low as 3.3 N / mm 2} , the judgment of the adhesive performance was "OK" because the wood part breaking rate of the adhesive performance was as high as 35%.

<Type of lamina (tree species): Larch (difficult-to-adhere wood)>
As is clear from Table 1, the laminated lumber of Comparative Example 2 in which water was not applied to the lower surface of the lamina had low adhesive performance strength and xylem breaking rate of 4.1 N / mm ² and 0%, respectively, and thus adhered. The judgment of performance was "impossible".

On the other hand, in the laminated lumber of Example 6 in which the amount of water applied was 15.1 g / m ² , the strength of the adhesive performance and the xylem breaking rate were 5.3 N / mm ² and 54%, respectively. Therefore, the judgment of adhesive performance was "excellent".

Although the spray amount of water mist ^{was within an appropriate range of 15.4 g / m 2} , the laminated wood of Comparative Example 7 in which water mist was sprayed on the upper surface of the lamina coated with the water-based adhesive had an adhesive performance. Since the strength and the breaking rate of the wood part were ^{as low as 4.5 N / mm 2} and 0%, respectively, the judgment of the adhesive performance was "impossible".

The laminated wood produced by the method of the present invention can be used for pillars, beams, girders, stairs, flooring and the like of wooden houses.

10 Laminated wood 11 Lamina 12 Water-based adhesive 13 Water

Claims (2)

An adhesive application step of applying a water-based adhesive to one surface of a plurality of laminas excluding the top or bottom lamina among a plurality of laminas, and a water system of another lamina from the surface to which the water-based adhesive of the lamina is applied In a method for producing laminated wood, which includes a laminated pressing step of laminating and compressing the plurality of laminas so as to be in contact with a surface to which an adhesive has not been applied.
Before the adhesive application step, or between the adhesive application step and the laminated pressing step, water is applied to the other surface of the plurality of laminas excluding the bottom or top lamina. method for producing a laminated wood, wherein a further comprising a water applying step of applying each of the coating amount ^{5g / m 2 ~25g / m 2} . Method for producing a laminated wood of the water of the coating amount according to claim 1, which is a ^{10g / m 2 ~20g / m 2} .

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