Flexible polyurethane foam, adhesive member, and molding die

Abstract

To provide a flexible polyurethane foam capable of improving the peel strength of an adherend, and to provide an adhesive member and a molding die.SOLUTION: A flexible polyurethane foam has an adhesive surface to which an adhesive is applied, and the adhesive surface has a plurality of protrusions. An adhesive member comprises a flexible polyurethane foam, an adherend, and an adhesive layer for bonding the adherend and the adhesive surface together. A molding die has a plurality of recesses at positions corresponding to the adhesive surface of the flexible polyurethane foam.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flexible polyurethane foam, an adhesive member, and a molding die. [Background technology]

[0002] Adhesives are sometimes used to attach adherends such as hook-and-loop fasteners to soft polyurethane foam (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-151904 A Summary of the Invention [Problem to be solved by the invention]

[0004] The prior art leaves room for improvement in peel strength of adherends bonded to flexible polyurethane foam.

[0005] The present invention has been made to solve this problem, and an object of the present invention is to provide a flexible polyurethane foam, an adhesive member and a molding die which are capable of improving the peel strength of an adherend. [Means for solving the problem]

[0006] A first aspect for achieving this object is a flexible polyurethane foam including an adhesive surface onto which an adhesive is applied, the adhesive surface being provided with a plurality of protrusions.

[0007] In the second embodiment, in the first embodiment, the height of the protrusions is 1 mm or more and 3 mm or less, and the pitch of the protrusions is 2 mm or more and 5 mm or less.

[0008] In a third embodiment, in the first or second embodiment, the adhesive surface is at the bottom of the groove.

[0009] A fourth aspect is an adhesive member, which comprises the flexible polyurethane foam of any one of the first to third aspects, an adherend, and an adhesive layer that bonds the adherend to the adhesive surface.

[0010] A fifth aspect is a mold for molding the flexible polyurethane foam of any one of the first to third aspects, which has a plurality of recesses formed at positions corresponding to the adhesive surface.

[0011] In a sixth aspect, in the fifth aspect, the depth of the recesses is 1 mm or more and 3 mm or less, and the pitch of the recesses is 2 mm or more and 5 mm or less.

[0012] A seventh embodiment is the fifth or sixth embodiment, wherein the depression is at the apex of the projection. Effect of the Invention

[0013] According to the present invention, since a plurality of protrusions are provided on the adhesive surface on which the adhesive is applied, the peel strength of the adherend adhered to the adhesive surface can be improved. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a front view of a flexible polyurethane foam in one embodiment. [Diagram 2] 1(a) is an enlarged view of a flexible polyurethane foam showing the part indicated by IIa in FIG. 1, (b) is a cross-sectional view of the flexible polyurethane foam taken along line IIb-IIb in (a), and (c) is a cross-sectional view of an adhesive member to which an adherend is fixed by adhesion. [Diagram 3] FIG. 2 is a plan view of a molding die according to one embodiment. [Figure 4] 4(a) is an enlarged view of the mold showing the portion indicated by IVa in FIG. 3, (b) is a cross-sectional view of the mold taken along line IVb-IVb in (a), and (c) is a cross-sectional view of the recess. [Diagram 5](a) is a plan view of a recess in a modified example, (b) is a cross-sectional view of the recess along line Vb-Vb in (a), (c) is a plan view of a recess in another modified example, and (d) is a cross-sectional view of the recess along line Vd-Vd in (c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a front view of a flexible polyurethane foam 10 in one embodiment. As an example of the flexible polyurethane foam 10, a pad (seat back) used as a backrest will be described. However, there is no limitation on the use of the flexible polyurethane foam 10. Other examples of the use of the flexible polyurethane foam 10 include a pad (seat cushion) that supports the buttocks, sofas, chair armrests, and footrests.

[0016] The flexible polyurethane foam 10 is a seat pad having a polyurethane body 11 with grooves 12 formed therein and covered with a skin (not shown). A part of the skin covering the body 11 is drawn into the grooves 12 and fixed to the body 11 within the grooves 12. The means for fixing the skin drawn into the grooves 12 to the body 11 is, for example, a hog ring.

[0017] Fig. 2(a) is an enlarged view of the flexible polyurethane foam 10, which is an enlarged view of the part indicated by IIa in Fig. 1. Fig. 2(b) is a cross-sectional view of the flexible polyurethane foam 10 taken along the line IIb-IIb. An adhesive surface 13 is provided at the bottom of a groove 12 provided in a body 11. A plurality of protrusions 14 are provided on the adhesive surface 13.

[0018] The adhesive surface 13 is a surface to which an adhesive is applied. An adherend 21 is attached to the adhesive surface 13 using an adhesive. There are no limitations on the adherend 21 as long as it can be attached to the flexible polyurethane foam 10 using an adhesive. Examples of the adherend 21 include cloth, leather, felt, and synthetic resin sheets such as urethane, as well as synthetic resin plates and blocks. The adherend 21 in this embodiment is a hook-and-loop fastener having hooks and loops provided on a flexible polyurethane foam sheet.

[0019] 2(c) is a cross-sectional view of an adhesive member 20 to which an adherend 21 is fixed by adhesion. The adhesive member 20 comprises a flexible polyurethane foam 10 provided with an adhesive surface 13, an adherend 21, and an adhesive layer 22 that bonds the adherend 21 and the adhesive surface 13. The adhesive layer 22 bonds the adhesive surface 13 and the adherend 21 by chemical or physical forces or both, using the cured adhesive as a medium. The adherend 21 is attached to the bottom (adhesive surface 13) of the groove 12 by the adhesive layer 22. A hook-and-loop fastener that pairs with the adherend 21 (hook-and-loop fastener) is attached to the surface (not shown), and the surface is fixed to the main body 11 by bonding the hook-and-loop fasteners together.

[0020] The adhesive that hardens to form the adhesive layer 22 can be appropriately selected from solvent-based adhesives, water-based adhesives, and hot melt adhesives, so long as it is suitable for bonding the flexible polyurethane foam 10 and the adherend 21. Water-based adhesives are preferable because they are less likely to catch fire compared to solvent-based adhesives, and can also reduce the concentration of volatile organic compounds (VOCs).

[0021] In this embodiment, the protrusions 14 provided on the adhesive surface 13 are cone-shaped. Since multiple protrusions 14 are provided on the adhesive surface 13, the bonding area between the adhesive surface 13 and the adhesive layer 22 can be made larger by the side surfaces of the protrusions 14 compared to a case where the adhesive surface 13 does not have the protrusions 14. This can improve the peel strength of the adherend 21.

[0022] In order to improve the peel strength of the adherend 21, the height T of the protrusions 14 is preferably 1 mm or more and 3 mm or less. The pitch P of the protrusions 14 is preferably 2 mm or more and 7 mm or less, particularly preferably 2 mm or more and 5 mm or less. The size S of the protrusions 14 is preferably 1 mm or more and 9 mm or less, particularly preferably 1 mm or more and 3 mm or less. In this embodiment, the four protrusions 14 are arranged in the width direction of the adhesive surface 13 (the bottom of the groove 12) and are arranged along the length direction of the groove 12, but this is not limited to this. The range in which the protrusions 14 are provided is appropriately set depending on the size of the adherend 21 and the width and length of the groove 12.

[0023] A mold 30 used for molding the flexible polyurethane foam 10 will be described with reference to Figs. 3 and 4. Fig. 3 is a plan view of the mold 30 in one embodiment. The mold 30 is a lower mold, and after a raw material containing a polyol component and an isocyanate component is injected into the mold 30, an upper mold and a core (neither of which are shown) are joined to the mold 30 to form a closed space. The raw material expands in the closed space due to two competitive reactions, a resinification reaction and a gasification reaction, between the polyol component and the isocyanate component, and the flexible polyurethane foam 10 is molded into the shape of the space. The mold 30 includes a bottom surface 31 provided with a protrusion 32. The protrusion 32 corresponds to the groove 12 provided in the main body 11 (see Fig. 1).

[0024] Fig. 4(a) is an enlarged view of the mold 30 showing a portion indicated by IVa in Fig. 3. Fig. 4(b) is a cross-sectional view of the mold 30 taken along line IVb-IVb. A plurality of recesses 34 are provided at the apex 33 of a protrusion 32 provided on the bottom surface 31. The apex 33 corresponds to the bonding surface 13 of the main body 11 (see Fig. 2(b)), and the recesses 34 correspond to the protrusions 14 provided on the bonding surface 13. In this embodiment, the recesses 34 are conical.

[0025] FIG. 4(c) is a cross-sectional view of the recess 34. The recess 34 has a function of retaining the release agent 35 applied to the mold 30 before the raw material containing the polyol component and the isocyanate component is injected into the mold 30. Since the recess 34 is present at the top 33 of the protrusion 32, the release agent 35 applied to the protrusion 32 does not flow down from the top 33 of the protrusion 32 to the bottom surface 31, but is stored in the recess 34 and is evenly applied to the top 33. When the raw material injected into the mold 30 expands by gasification reaction and enters the recess 34, and the protrusion 14 (see FIG. 2(b)) is formed, a film is formed on the surface of the protrusion 14 by the volatilized release agent 35. This film improves the wettability of the protrusion 14. It is presumed that the surface of the protrusion 14 is more likely to have voids (open pores) that communicate with the outside.

[0026] When an adhesive is applied to the bonding surface 13 including the protrusions 14 to bond the adherend 21 (see FIG. 2(b)), the adhesive is more likely to adhere to the surfaces of the protrusions 14 and more likely to penetrate into the open pores of the protrusions 14. As a result, the bonding force between the protrusions 14 on the bonding surface 13 and the adhesive layer 22 is more stable, improving the peel strength of the adherend 21.

[0027] In order to improve the peel strength of the adherend 21, the depth D of the recesses 34 is preferably 1 mm or more and 3 mm or less. The pitch P of the recesses 34 is preferably 2 mm or more and 7 mm or less, particularly preferably 2 mm or more and 5 mm or less. The size S of the recesses 34 is preferably 1 mm or more and 9 mm or less, particularly preferably 1 mm or more and 3 mm or less. In this embodiment, the recesses 34 are arranged in four in the width direction of the apex 33 of the protrusion 32, and are arranged along the length direction of the apex 33, but this is not limited to this. The range in which the recesses 34 are provided is appropriately set depending on the size of the adherend 21.

[0028] Fig. 5(a) is a plan view of a recess 36 in a modified example. Fig. 5(b) is a cross-sectional view of the recess 36 taken along the line Vb-Vb. The recess 36 provided at the apex 33 has a spherical crown shape. The projection of the flexible polyurethane foam formed by the recess 36 has a spherical crown shape. The recess 36, like the recess 34 (see Fig. 4(b)), has the function of retaining the release agent and applying the release agent evenly. The depth D of the recess 36 is preferably 1 mm or more and 3 mm or less.

[0029] Fig. 5(c) is a plan view of recess 37 in another modified example. Fig. 5(d) is a cross-sectional view of recess 37 taken along line Vd-Vd. Recess 37 formed at apex 33 has a shape of a cylinder cut vertically in half. The projection of the soft polyurethane foam formed by recess 37 has a shape of a cylinder cut vertically in half. Recess 37 has the same function as recess 34 (see Fig. 4(b)) in that it stores a release agent. The depth D of recess 37 is preferably 1 mm or more and 3 mm or less. EXAMPLES

[0030] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0031] Example 1 Similar to the mold 30 in the embodiment, a mold 30 was prepared in which a plurality of conical depressions 34 (see FIG. 4(b)) were provided on the apex 33 of the protrusion 32. The depressions 34 had a depth D of 1.5 mm, a size S of 2 mm, and a pitch P of 3.5 mm. Three depressions 34 were arranged in a row in the width direction of the apex 33, and 15 such rows were arranged in the length direction of the apex 33.

[0032] After applying a mold release agent 35 to the mold 30, a raw material containing a polyol component and an isocyanate component was injected into the mold 30, the upper mold was placed over the lower mold and closed, and after the reacted raw material was cured, the upper mold was opened and removed to form a flexible polyurethane foam. The bottoms (adhesive surfaces 13) of the grooves 12 of the molded flexible polyurethane foam had a row of protrusions 14 corresponding to the recesses 34.

[0033] Using an adhesive (Bond WG200 Blue, Konishi Co., Ltd.), a hook-and-loop fastener (male) (AP255, Kuraray Fastening Co., Ltd.) having a width of 10 mm and a length of 40 mm was adhered to the adhesive surface 13 of the flexible polyurethane foam 10. The adhesive member in Example 1 was obtained by curing for 24 hours in a room at a temperature of 23°C and a relative humidity of 50%.

[0034] A hook was attached to the center of the backside of a hook-and-loop fastener (female) (QUICKLOOP (registered trademark), YKK Corporation) with a width of 10 mm and a length of 38 mm, and the male and female hook-and-loop fasteners were joined together. After that, the hook was pulled perpendicular to the adhesive surface 13 at a speed of 50 mm / min using a force gauge, and the force (peel strength) was measured when the hook-and-loop fastener (adherend) peeled off from the adhesive surface 13. The average peel strength was 64.8 N, with a standard deviation of 0.5 N.

[0035] Example 2 The pitch P of the depressions 34 in the width direction of the apex 33 of the mold 30 was 7.0 mm (the pitch P of the depressions 34 in the length direction of the apex 33 was 3.5 mm). The adhesive member in Example 2 was produced in the same manner as in Example 1, except that two depressions 34 were arranged in a row in the width direction of the apex 33, and 15 rows were arranged in the length direction of the apex 33. The average peel strength was 41.4 N, and the standard deviation was 3.5 N.

[0036] Example 3 An adhesive member in Example 3 was produced in the same manner as in Example 1, except that a spherical crown-shaped depression 36 (see FIG. 5(a)) was provided in the mold 30 and the depth D of the depression 36 was set to 1.0 mm. The average peel strength was 48.6 N, with a standard deviation of 1.2 N.

[0037] Example 4 A depression 37 (see FIG. 5(c)) in the shape of a cylinder cut in half vertically was provided in the molding die 30. The size of the depression 37 in the width direction of the apex 33 was 9 mm, the pitch of the depression 37 in the length direction of the apex 33 was 3.5 mm, and the depth of the depression 37 was 1.0 mm. The adhesive member in Example 4 was produced in the same manner as in Example 1, except that one depression 37 was provided in the width direction of the apex 33 and 15 rows were arranged in the length direction of the apex 33. The average peel strength was 42.6 N, and the standard deviation was 9.1 N.

[0038] (Comparative Example) An adhesive member in a comparative example was produced in the same manner as in Example 1, except that a flexible polyurethane foam having a groove 12 was molded without forming a recess 34 on the apex 33 of the protrusion 32 of the molding die 30. The average peel strength was 32.1 N.

[0039] It was found that the adhesive members in Examples 1-4 could increase the peel strength compared to the adhesive members in Comparative Examples that had no protrusions on the adhesive surface 13. In particular, it was confirmed that the adhesive members in Examples 1 and 3, which were molded using a mold having a recess depth of 1 mm to 3 mm and a recess pitch of 2 mm to 5 mm, could increase the average peel strength and reduce the standard deviation compared to the adhesive members in Examples 2 and 4. It was also confirmed that the adhesive member in Example 1, which was molded using a mold having recesses with a depth of 1.5 mm or more, could increase the average peel strength and reduce the standard deviation compared to the adhesive member in Example 3.

[0040] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily imagined that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

[0041] In the embodiment, the case where the adhesive surface 13 is provided at the bottom of the groove 12 in the main body 11 of the flexible polyurethane foam 10 has been described, but this is not necessarily limited to this. It is of course possible to provide the adhesive surface 13 at a required position on the main body 11, not limited to the bottom of the groove 12, depending on the application of the flexible polyurethane foam 10. The molding die 30 has recesses 34, 36, 37 provided at positions corresponding to the adhesive surface 13 of the flexible polyurethane foam 10.

[0042] In the above embodiment, the recesses 34, 36, and 37 are exemplified by a cone shape, a spherical crown shape, and a shape obtained by cutting a cylinder in half lengthwise, but the shape is not limited to these. Other shapes of the recesses include a spindle shape cut in half widthwise or lengthwise. The same applies to the shape of the protrusions.

[0043] In the embodiment, the case where the recesses 34, 36, 37 are provided on the bottom surface 31 of the molding die 30 (lower die) has been described, but this is not necessarily limited to this. It is of course possible to provide recesses in the core or upper die (molding die) depending on the application of the flexible polyurethane foam. [Explanation of symbols]

[0044] 10 Soft polyurethane foam 12 grooves 13 Adhesive surface 14 protrusions 20 Adhesive material 21 Adherent material 22 Adhesive layer 30 mold 32 Convex 33 Top 34, 36, 37 Dent

Claims

1. 1. A flexible polyurethane foam including an adhesive surface to which an adhesive is applied, A flexible polyurethane foam having a plurality of protrusions on the adhesive surface.

2. 2. The flexible polyurethane foam according to claim 1, wherein the height of said projections is from 1 mm to 3 mm, and the pitch of said projections is from 2 mm to 5 mm.

3. 2. The flexible polyurethane foam according to claim 1, wherein said adhesive surface is at the bottom of said grooves.

4. An adhesive member comprising the flexible polyurethane foam according to claim 1 , an adherend, and an adhesive layer that bonds the adherend and the adhesive surface.

5. A mold for molding the flexible polyurethane foam according to any one of claims 1 to 3, A molding die having a plurality of recesses at positions corresponding to the adhesive surface.

6. 6. The mold according to claim 5, wherein the depth of the recesses is 1 mm or more and 3 mm or less, and the pitch of the recesses is 2 mm or more and 5 mm or less.

7. The mold according to claim 5, wherein the recess is at the apex of the protrusion.

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