Knife coater

Abstract

To provide a coating apparatus which makes the repair of a defective part compatible with the coating of an adhesive in a coating amount necessary for adhesion to plywood.SOLUTION: A knife coater for applying an adhesive to an entire surface or a part of a surface of a plate-shaped object to be coated which is continuously or intermittently conveyed, the knife coater comprising: a knife member; and a pressure filling auxiliary member, wherein a plurality of notches having a shape through which the adhesive can pass when the plate-shaped object to be coated is conveyed are formed side by side in a blade edge portion of the knife member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a knife coater for applying an adhesive to the surface of a substrate such as plywood or veneer. [Background technology]

[0002] 2. Description of the Related Art Coating devices such as roll coaters and knife coaters are used to apply a coating liquid to the surface of a substrate such as plywood or veneer.

[0003] An example of a substrate is softwood plywood (hereinafter simply referred to as plywood) that has depression-like defects on its surface, such as cracks, pinholes, knots, splits, and ducts. Domestically produced flooring uses a base material made of softwood plywood with medium-density fiberboard (MDF) glued to it. Even if MDF is used as an overlay, the presence of these defects on the surface of the softwood plywood poses problems for the quality and performance of the flooring product, such as caster resistance. Therefore, it is common practice to fill and repair defects on the surface of the softwood plywood with putty or similar. To manufacture the base material, first, defects in the softwood plywood are repaired with putty (water-based paint) using a knife coater. Next, after the putty filled in the defects is allowed to harden completely, the unnecessary putty on the surface is ground away with a sander to make it smooth.

[0004] Then, adhesive is applied to the smoothed softwood plywood using a roll coater, and MDF is attached to produce a base material. When attaching MDF to softwood plywood, 210 g / m of adhesive is used. 2 Since a certain amount of adhesive is required, a roll coater is generally used to apply the adhesive evenly to the plywood.

[0005] The above method requires a process of applying putty or the like with a knife coater to repair defects on the plywood surface, followed by a process of grinding to smooth the surface, and a process of applying adhesive to the softwood plywood with a roll coater, and also requires waiting time for the putty to harden. Therefore, studies have been conducted to apply adhesive to the board surface using only a knife coater to repair defects, without using a roll coater (Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-120324 [Patent Document 2] Japanese Patent Application Publication No. 6-312406 Summary of the Invention [Problem to be solved by the invention]

[0007] However, since the knife coater is a device that applies paint while squeezing the plate surface with the knife member of the coating section, the maximum coating density is 100 g / m 2 In fact, in the inventions described in Patent Documents 1 and 2, the amount of adhesive applied is 80 to 100 g / m in the examples. 2 The results are limited to this level, and no consideration has been given to increasing the amount of adhesive applied. One possible method for increasing the amount of adhesive applied using a knife coater is to reduce the pressure applied to the cutting edge of the knife member, but this method does not allow for a uniform increase in the amount of adhesive applied over the entire board surface due to uneven thickness of softwood plywood, uneven hardness due to wood grain, and even warping or warping of the plywood, resulting in areas with more and areas with less applied. In areas with less applied adhesive, there is not enough adhesive to properly bond the board, resulting in poor adhesion. The inventors have determined that, although it depends on the viscosity of the adhesive, a uniform amount of adhesive that can be applied using a conventionally known knife coater is 70 g / m 2 It has been found that there is a limit to the extent

[0008] Knife coaters can repair defects in plywood, but they cannot apply the amount of adhesive needed to bond the plywood. On the other hand, roll coaters can apply the amount of adhesive needed to bond the plywood, but they cannot repair defects in the plywood. In other words, a single applicator cannot both repair defects and apply the amount of adhesive needed to bond the plywood. Therefore, there was a need for an applicator that could both repair defects and apply the amount of adhesive needed to bond the plywood. [Means for solving the problem]

[0009] In view of the above circumstances, the inventors have conducted extensive research and have discovered that a knife coater which includes a knife element and a pressure-filling auxiliary element and which applies adhesive to all or part of the surface of a plate-shaped substrate which is transported continuously or intermittently, can repair defective portions of plywood with adhesive and apply the amount of adhesive required for bonding to the plywood by providing a plurality of cutouts at the cutting edge of the knife element which are shaped to allow the adhesive to pass through as the plate-shaped substrate is transported, thereby completing the present invention.

[0010] That is, the present invention is a knife coater for applying an adhesive to the entire or part of the surface of a plate-like object to be coated that is transported continuously or intermittently, the knife coater comprising a knife member and a pressure filling auxiliary member, The present invention relates to a knife coater characterized in that the cutting edge of the knife member is formed with a plurality of cutouts arranged in a row, which are shaped to allow the adhesive to pass through when the plate-shaped substrate is being transported.

[0011] When the upper surface of the knife member is viewed from above in a vertical direction, the total area of ​​the plurality of cutout portions is 200 to 430 mm per 1 m of the longitudinal length of the knife member. 2 It is preferable that the temperature is in the range of

[0012] The distance between the edge of one notch on the cutting edge and the edge of the adjacent notch on the cutting edge is preferably in the range of 0.1 to 5 mm. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a knife coater that can repair defects in plywood with adhesive and can apply the amount of adhesive required for bonding to the plywood. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic side view showing one embodiment of the knife coater of the present invention. [Figure 2] FIG. 2 is a schematic perspective view of a knife member in one embodiment of the knife coater of the present invention. [Figure 3] FIG. 3 is a schematic top view of the cutting edge of the knife member of the present invention, when the upper surface thereof is viewed from the vertical direction (the notch has a triangular shape). [Figure 4] FIG. 4 is a schematic top view of the cutting edge of the knife member of the present invention, when the upper surface thereof is viewed from the vertical direction (the notch has a rectangular shape). [Figure 5] FIG. 5 is a schematic top view of the cutting edge of the knife member of the present invention, when the upper surface thereof is viewed from the vertical direction (the notch has a semicircular shape). [Figure 6] FIG. 6 is a schematic side view showing another embodiment of the knife coater of the present invention. [Figure 7] FIG. 7 is a schematic side view showing yet another embodiment of the knife coater of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the knife coater according to the present invention will be described in detail with reference to the drawings. In this specification, when a numerical value represents a physical property value, a characteristic value, etc., the expression "(numerical value 1) to (numerical value 2)" means "(numerical value 1) or more and (numerical value 2) or less."

[0016] First, an example of a knife coater 1 of the present invention will be described with reference to Figure 1. The knife coater 1 applies an adhesive 9 to the entire surface or part of a plate-shaped substrate 2, and comprises at least a knife member 3 and a pressure filling auxiliary member 4. As shown in Figure 2, the cutting edge 3B of the knife member is formed with a plurality of notches 5 shaped to allow the adhesive 9 to pass through when the plate-shaped substrate 2 is transported. The rest of the configuration of the knife coater 1 can be the same as that of known knife coaters.

[0017] The knife member 3 is a coating member that controls the amount of adhesive 9 applied and has the function of adjusting the amount of adhesive 9 applied (thickness of the applied film). In the knife coater 1 of FIG. 1, the knife member 3 is provided so as to be in pressure contact with the pressure filling auxiliary member 4.

[0018] In a top view of the upper surface 3C of the knife member shown in FIG. 2 viewed from the vertical direction, the notch 5 is formed in a quadrangular shape as shown in FIG. 4. The notch 5 may have various shapes. Examples include, but are not limited to, the triangular shape shown in FIG. 3 and the semicircular shape shown in FIG. 5. For example, a polygonal shape, a bow shape formed by cutting off a part of a circle, or a horseshoe shape may also be used. From the viewpoint of processability, a triangular shape, a quadrangular shape, and a semicircular shape are preferred, and a quadrangular shape is more preferred from the viewpoint of coating amount stability during wear of the cutting edge 3B of the knife member. Note that the multiple notches 5 may have a mixture of these shapes. Therefore, the multiple notches 5 may have, for example, triangular and quadrangular shapes arranged alternately, or they may be arranged irregularly.

[0019] In the present invention, the total area of ​​the notches 5 of the knife coater 1 is 200 to 430 mm per 1 m of the longitudinal length of the knife member 3. 2 It is preferable that the range is 210 to 410 mm. 2 It is more preferable that the range is 220 to 400 mm. 2 More preferably, the range is 230 to 380 mm. 2 It is even more preferable that the range is 240 to 370 mm.2 It is particularly preferable that the range is 250 to 360 mm. 2 It is even more particularly preferable that the total area of ​​the notches is in the range. If the total area of ​​the notches is in the above range, uneven application can be reduced and bleeding of the adhesive when bonding plywood can be further suppressed. The area of ​​one notch 5 is the area of ​​the region surrounded by straight lines connecting the edges 5B (hereinafter simply referred to as edges 5B) on the cutting edge of the notch. For example, in the case of the rectangular shape shown in Figure 4, the length of the straight line connecting the edges 5B corresponds to the width W of the notch, and the notch area of ​​one notch 5 is determined by multiplying the width W of the notch by the height H of the notch. The area of ​​one notch 5 is, for example, 0.25 mm 2 Exceeding 2.25mm 2 Within the range of less than 0.3 to 2.2 mm, for example 2 For example, the range is 0.4 to 2.1 mm. 2 For example, the range is 0.5 to 2.0 mm. 2 For example, 1.5 to 2.0 mm 2 The sum of the areas of the cutouts 5 is the total area of ​​the cutout areas.

[0020] The distance L between the edge of one notch on the cutting edge and the edge of the adjacent notch on the cutting edge (hereinafter simply referred to as distance L) is preferably in the range of 0.1 to 5 mm, more preferably in the range of 0.2 to 4.7 mm, even more preferably in the range of 0.3 to 4.5 mm, even more preferably in the range of 0.4 to 4 mm, particularly preferably in the range of 1 to 4 mm, and even particularly preferably in the range of 2 to 4 mm. When the distance L is in the above range, uneven coating can be reduced. As long as it is within this range, the distance L does not necessarily have to be equal. For example, distances L of 1 mm and 5 mm may be alternately arranged, or may be unevenly arranged. However, from the viewpoint of reducing uneven coating, it is preferable that the distances are equal.

[0021] The width W of the cutout portion is, for example, in the range of 0.1 to 5 mm, for example, in the range of 0.5 to 5 mm, for example, in the range of 0.3 to 4 mm, for example, in the range of 0.5 to 3 mm, for example, in the range of 0.75 to 2 mm, or for example, in the range of 1 to 2 mm.

[0022] The height H of the cutout is, for example, in the range of 0.1 to 5 mm, for example, in the range of 0.5 to 5 mm, for example, in the range of 0.3 to 4 mm, for example, in the range of 0.5 to 3 mm, for example, in the range of 0.75 to 2 mm, or for example, in the range of 1 to 2 mm.

[0023] The knife member 3 does not necessarily need to be disposed so that the edge of its bottom surface on the upstream side in the conveying direction is perpendicular (90 degrees) to the conveying direction, and can be disposed at an angle within a range that does not cause defects in the application and filling of the adhesive 9. For example, if the conveying direction is 12 o'clock and clockwise is the positive direction, the knife member 3 is preferably disposed so that the edge of its bottom surface on the upstream side in the conveying direction is at an angle of 85 degrees to 95 degrees, excluding the perpendicular (90 degrees), with respect to the conveying direction, more preferably 87 degrees to 93 degrees, and even more preferably 89 degrees to 91 degrees.

[0024] The pressure filling auxiliary member 4 in the present invention has a main body 4B extending in a direction intersecting the conveyance direction of the plate-shaped workpiece 2, upstream of the knife member 3 in the conveyance direction of the plate-shaped workpiece 2, and is pressed against the knife member 3. The pressure at which the pressure filling auxiliary member 4 is pressed against the knife member 3 is not particularly limited, and is, for example, in the range of more than 0 Pa and less than 10 MPa. Examples of the pressure filling auxiliary member 4 include the pressure filling auxiliary member described in JP-A-7-256607 and the filling auxiliary member described in JP-A-2021-24190.

[0025] A conventionally known adhesive can be used as the adhesive 9. For example, the viscosity of the adhesive is preferably in the range of 3 to 50 Pa·s / 23°C. The viscosity is measured in accordance with JIS Z 8803 (2011) "Method for measuring viscosity of liquids." The solid content of the adhesive is preferably in the range of 40 to 90%, more preferably in the range of 40 to 70%. In this specification, the solid content refers to the components of the adhesive excluding water or organic solvent. The adhesive may further contain an aqueous emulsion and / or aqueous latex, a crosslinking agent, etc.

[0026] Examples of aqueous emulsions include acrylic resins, acrylic acid-acrylic acid ester copolymer resins, acrylic-styrene copolymer resins, acrylic-ethylene-styrene copolymer resins, ethylene vinyl acetate resins, aqueous urethane resins, and vinyl acetate resins. Water-based latexes include styrene butadiene latex (SBR) and carboxylated chloroprene rubber latex. These aqueous emulsions and aqueous latexes can be used singly or in combination of two or more.

[0027] Examples of crosslinking agents include aminoalkylsilanes such as γ-aminopropyltriethoxysilane and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane; epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane; chlorosilanes such as vinyltrichlorosilane, γ-chloropropyltrimethoxysilane and γ-chloropropylmethyldichlorosilane; and organic silanes such as γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane and vinyltriethoxysilane. Compounds include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate (C-MDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), hydrogenated TDI, hydrogenated MDI, and modified products or mixtures thereof. These crosslinking agents can be used alone or in combination of two or more. The content of the crosslinking agent is usually 0.01 to 15 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the aqueous emulsion and / or aqueous latex.

[0028] The adhesive 9 may further contain additives commonly used in adhesives, such as fillers such as talc and clay; tackifiers such as sodium polyacrylate, polyvinyl alcohol and cellulose ether; thickeners; surfactants; diluents; antifoaming agents; dispersants; and pigments.

[0029] When gluing MDF to plywood, the amount of adhesive 9 to be applied is 1 m 2 per, e.g. 120g / m 2 Over 300g / m 2 The range is preferably 130 to 290 g / m 2 More preferably, it is in the range of 140 to 280 g / m 2 More preferably, it is in the range of 150 to 270 g / m 2 and even more preferably in the range of 160 to 260 g / m 2 and particularly preferably 150 to 250 g / m 2 and more particularly preferably in the range of 190 to 220 g / m 2 is within the range.

[0030] Examples of the knife coater of the present invention are shown in FIGS. As shown in FIG. 6, in the knife coater of the present invention, the pressure filling assistant member 4 may be disposed via a positioning member 7 . 6, the positioning member 7 of this embodiment is made of a highly rigid steel plate having a substantially Z-shaped configuration in side view, and is attached to the support member 6 that supports the knife member 3. In the knife coater of this embodiment, the pressure filling auxiliary member 4 can be positioned by adjusting the attachment position of the positioning member 7 relative to the support member 6. The width and number of the positioning members 7 in plan view can be selected as appropriate. For example, a single positioning member with a wide width can be used, or multiple positioning members with a narrow width can be used.

[0031] Figure 7 is a schematic side view showing yet another embodiment of the knife coater of the present invention, which is provided with a pipe or squeeze roll 8 connected to a pressure cylinder 10. As shown in Figure 7, the knife member 3 is pressed toward the plate-like substrate 2 by the pipe or squeeze roll 8 connected to the pressure cylinder 10, and the tip end on the downstream side in the conveyance direction is pressed against the surface of the plate-like substrate 2. This type of knife coater of the present invention can apply coating by a contour pressure coating method, in which the knife member 3 is pressed against the surface of the plate-like substrate 2 (Japanese Patent Laid-Open Publication No. 3-136806). [Example]

[0032] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0033] [Example 1] A knife member having a thickness of 1.0 mm is provided with a plurality of triangular cutouts shown in FIG. 3 (the width W of the cutout is 2 mm, the height H of the cutout is 2 mm, the interval L is 4 mm, the repeat unit (hereinafter also simply referred to as the repeat unit) obtained by adding the width W and the interval L of the cutout is 6 mm, the number of cutouts per 1 m length in the longitudinal direction of the knife member is 167, and the number of cutouts per 1 m length in the longitudinal direction of the knife member is 167. The total area of ​​the notch is 333 mm 2 / m) was provided to obtain the knife member of Example 1.

[0034] [Examples 2 to 6] The shape, width, height, and spacing of the notches were changed as shown in Table 1 to obtain knife members of Examples 2 to 6.

[0035] [Examples 7 to 11] The shape, width, height, and spacing of the notches were changed as shown in Table 2 to obtain knife members of Examples 7 to 11.

[0036] [Table 1]

[0037] [Table 2]

[0038] A support member was attached to the knife member of Example 1, and a pressure-filling assist member was further attached via a positioning member. In addition, a squeeze roll was provided to the knife member, and the knife coater of Example 1 having the configuration shown in Figure 6 was prepared.

[0039] The knife members were replaced with the knife members of Examples 2 to 11, respectively, and the same members as those described above were attached to prepare knife coaters of Examples 2 to 11 each having the configuration shown in FIG.

[0040] A normal knife member having a thickness of 1.0 mm and no notch was used as the knife member of Example 12, and a member similar to that described above was attached to prepare a knife coater of Example 12 having the configuration shown in Figure 6 without a notch. In Example 13, a roll coater (manufactured by Shimazaki Manufacturing Co., Ltd.) was prepared instead of the knife coater of the present invention.

[0041] <Adhesive> A homogeneous liquid composition was obtained by kneading for 10 minutes using a stirring kneader (Homodisper 2.5 model manufactured by Primix Corporation) the respective reagents shown in Table 3 below in the respective blending amounts shown in Table 3 below. The values ​​in Table 3 represent parts by mass, and the base agent and crosslinking agent were mixed before use.

[0042] [Table 3]

[0043] <Coating amount evaluation> A 5-ply softwood plywood with dimensions of 303 mm wide x 1840 mm long and 9 mm thick was selected for the plywood base. Also, a 303 mm wide x 1840 mm long x 1.5 mm thick MDF was selected. Using the knife coaters of Examples 1 to 12 and the roll coater of Example 13, the adhesives listed in Table 3 were applied to the plywood base at a set application rate of 20 g / shaku2 under conditions of a line speed of 20 m / min and a pressing pressure of 0.2 MPa. Then, the adhesives were applied to the plywood base at a set application rate of 20 g / shaku2. 2 The actual amount of coating per unit area was measured (the results are shown in Tables 4 and 5). Then, the MDF was adhered to the upper surface of the plywood base plate, and a coating pressure of 10 kg / cm was applied. 2 The mixture was then subjected to cold pressing at 23° C. for 7 days to form test substrates for Examples 1 to 13. During cold pressing, the wood was visually inspected for adhesive seepage from the end grain and evaluated according to the following criteria A, B, and C. The results are shown in Tables 4 and 5. A: The adhesive that seeps out does not drip, but forms small droplets. B: The glue has seeped out and is dripping, but it stops halfway up the edge of the wood. C: The adhesive drips down to the bottom of the wood edge, or there is no adhesive seeping out.

[0044] <Evaluation of coating unevenness> The uneven coating was evaluated by a flat tensile test in accordance with the Japanese Agricultural Standards (JAS) for plywood. First, square test pieces measuring 50 mm on a side were cut from the test substrates of Examples 1 to 13. Next, a metal plate with a 20 mm square adhesive surface was attached to the center of the test piece using a cyanoacrylate adhesive. Score marks were made around the periphery, reaching the plywood base. The test piece and metal plate were then secured in a chuck and pulled perpendicular to the adhesive surface at a load rate of 5880 N / min or less to separate the plywood base from the MDF. The adhesion rate of the adhesive, plywood, or MDF on the peeled adhesive surface was calculated and evaluated according to the following criteria A to C. The results are shown in Tables 4 and 5. A: 81~100% B + :61~80% B: 41-60% B - :21~40% C: 0-20%

[0045] <Evaluation of filling level of defects> Test substrates of Examples 1 to 13 were molded under the same conditions as those described in <Evaluation of coating amount>, except that a plywood base plate with an artificial knot (depth 1.8 mm, diameter 30 mm) created with a router was used. The area where the artificial knot was located (defective area) was cut with a circular saw, and the adhesive-filled area was visually observed from the cross section to calculate the filling rate of the defective area, which was then evaluated according to the following criteria A, B, and C. The results are shown in Tables 4 and 5. A: 67-100% B: 34-66% C: 0-33%

[0046] [Table 4]

[0047] [Table 5] [Industrial Applicability]

[0048] The knife coater of the present invention can repair defects in plywood with adhesive and can also apply the amount of adhesive required for bonding to the plywood, so it is suitable for use in, for example, domestically produced plywood. The resulting flooring substrate can be produced in fewer steps than with conventionally known methods. [Explanation of symbols]

[0049] 1 knife coater 2 Plate-shaped object to be coated 3 Knife parts 3B Cutting edge of knife component 3C Upper surface of knife member 4 Pressure filling auxiliary parts 4B Main body of pressure filling auxiliary member 4D Bottom surface of the main body of the pressure filling auxiliary part 5 Notch 5B Edge on cutting edge of notch 6 Support member 7 Positioning member 8 Squeeze Roll 9. Adhesive 10 Pressure Cylinder H Height of the notch W Width of the notch L: The distance between the edge of one notch on the cutting edge and the edge of the adjacent notch on the cutting edge

Claims

1. A knife coater that applies adhesive to the entire or part of the surface of a plate-like object to be coated that is transported continuously or intermittently, the knife coater comprising a knife member and a pressure filling auxiliary member, A knife coater characterized in that the cutting edge of the knife member is formed with a plurality of notches arranged in a row, the notches being shaped to allow the adhesive to pass through when the plate-shaped substrate is being transported.

2. When the upper surface of the knife member is viewed from above in a vertical direction, the total area of ​​the plurality of cutout portions is 200 to 430 mm per 1 m of the longitudinal length of the knife member. ２ 2. The knife coater according to claim 1, wherein the coating thickness is in the range of 100 μm to 150 μm.

3. 2. The knife coater according to claim 1, wherein the distance between the edge of one notch on the cutting edge and the edge of the adjacent notch on the cutting edge is in the range of 0.1 to 5 mm.

Images