Pocket coil mattress

Abstract

A pocket coil mattress that combines ease of disassembly at home with excellent cushioning performance during use. [Solution] The device comprises a group of spring coils 10G densely arranged on a plane, a plurality of rows of bag-like bodies 10 that individually house a plurality of rows of spring coils constituting the group of spring coils, a sheet-like first core material 11 that is bonded to a first end surface 10U which is either the top or bottom of the plurality of rows of bag-like bodies, and a sheet-like second core material 12 that is bonded to a second end surface 10B which is the other of the top or bottom of the plurality of rows of bag-like bodies, and cooperates with the first core material to limit the elastic deformation of the group of spring coils, wherein the first core material has a soft layer 11B that is bonded to the first end surface and a hard layer 11U that is laminated on the soft layer, and each of the plurality of rows of bag-like bodies has a pre-cut line around its circumference that allows the user to tear the bag-like body by hand after peeling off the first core material to expose the group of spring coils.

Description

[[TECHNICAL FIELD]]

[0001] The present invention relates to a pocket coil mattress in which bag-shaped bodies accommodating spring coil rows are arranged side by side, and sheet-shaped core materials are bonded so as to sandwich a plurality of rows of the bag-shaped bodies. [[BACKGROUND ART]]

[0002] Figure 8 of Patent Document 1 discloses a mattress 20 having a plurality of pocket coils. The mattress 20 includes bag-shaped nonwoven fabrics 250, 250, ... having pocket spaces S1, S1, ... for accommodating coil springs 223a, 223a, ..., adhesives 80, 80, ... for bonding adjacent bag-shaped nonwoven fabrics 250, 250, sheet-shaped nonwoven fabrics 222 and 224 bonded to the bag-shaped nonwoven fabrics 250, 250, ... so as to be sandwiched from above and below, and perforations 252, 252, ... provided in the bag-shaped nonwoven fabrics 250, 250, ...

[0003] When the mattress 20 becomes a discarded product, peeling the sheet-shaped nonwoven fabric 222 from the bag-shaped nonwoven fabrics 250, 250, ... applies a large force to the perforations 252, 252, ... and breaks the bag-shaped nonwoven fabrics 250, 250, ..., so that the upper sides of the pocket spaces S1, S1, ... are opened. Then, by taking out the coil springs 223a, 223a, ... from the opening, the coil springs 223a, 223a, ... which are metal materials can be separated from other materials. [[PRIOR ART DOCUMENT]] [[PATENT DOCUMENT]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2023-060974 [[SUMMARY OF THE INVENTION]] [[Problem to be Solved by the Invention]]

[0005] Many pocket coil mattresses are distributed in compressed roll packaging to reduce transportation costs. During the compression roll packaging process, a force greater than a person's weight is applied. For example, if the sheet-like nonwoven fabric 222 described in Patent Document 1 peels off at an unintended time, the elastic deformation direction of the coil springs 223a, 223a, ... becomes inappropriate, potentially reducing the cushioning performance that affects the comfort of the mattress. To prevent such unintended disassembly, the components of a pocket coil mattress are firmly fixed together with adhesive beforehand. Therefore, currently, it is extremely difficult to dismantle the components of a discarded pocket coil mattress at home, and many municipalities designate them as "difficult-to-dispose-of items," requiring disposal by specialized companies or retailers at high cost. As a result, even if a pocket coil mattress contains combustible or recyclable materials, it cannot be collected by municipalities as properly sorted household waste.

[0006] For example, the mattress 20 shown in Patent Document 1 may shorten the time required to remove the coil springs 223a, 223a, ... but it requires considerable force to disassemble because the sheet-like nonwoven fabric 222 must be peeled off together with the upper part of the bag-like nonwoven fabric 250. Furthermore, even if sufficient force is applied to peel it off, there is a problem in that the bag-like nonwoven fabrics 250, 250, ... cannot be directly applied to the perforations 252, 252, ... when peeling off the sheet-like nonwoven fabric 222, so it is not guaranteed that the bag-like nonwoven fabrics 250, 250, ... will break at the perforations 252, 252, ... as expected.

[0007] Therefore, the present invention has been made in view of these problems, and aims to provide a pocket coil mattress that combines ease of disassembly at home with cushioning performance during use. [Means for solving the problem]

[0008] A pocket coil mattress according to the present invention is a pocket coil mattress comprising a group of spring coils densely arranged on a plane, comprising: a plurality of rows of bag-like bodies that individually house a plurality of rows of spring coils constituting the group of spring coils; a sheet-like first core material adhered to a first end face which is either the top or bottom of the plurality of rows of bag-like bodies; and a sheet-like second core material adhered to a second end face which is the other of the top or bottom of the plurality of rows of bag-like bodies, and cooperating with the first core material to limit the elastic deformation of the group of spring coils, wherein the first core material has a soft layer adhered to the first end face and a hard layer laminated on the soft layer, and at least the hard layer of the first core material can be peeled off by hand from the bag-like bodies while the bag-like bodies remain fixed to the second core material, and each of the plurality of rows of bag-like bodies is provided with a cut line in advance for the user to tear the bag-like body by hand after peeling off the first core material to expose the group of spring coils.

[0009] In any pocket coil mattress according to the present invention, the thickness of the soft layer may be kept smaller than the thickness of the hard layer.

[0010] In any pocket coil mattress according to the present invention, the thickness of the soft layer may be within the range of 8% to 34% of the thickness of the hard layer.

[0011] In any pocket coil mattress according to the present invention, the peel strength of the hard layer to the soft layer may be kept lower than the peel strength of the second core material to the second end face.

[0012] In any pocket coil mattress according to the present invention, the peel strength of the hard layer to the soft layer may be within the range of 57% to 92% of the peel strength of the second core material to the second end face.

[0013] In any pocket coil mattress according to the present invention, the peel strength of the hard layer over the soft layer may be within the range of 40N to 55N.

[0014] In any pocket coil mattress according to the present invention, the first core material is a mixture of fiber components and adhesive components, and the proportion of adhesive components in the soft layer may be kept lower than the proportion of adhesive components in the hard layer.

[0015] In any pocket coil mattress according to the present invention, the proportion of adhesive components in the soft layer may be within the range of 40% to 75% of the proportion of adhesive components in the hard layer.

[0016] In any pocket coil mattress according to the present invention, the strength of the adhesive used to bond the first core material to the first end face may be kept lower than the strength of the adhesive used to bond the second core material to the second end face.

[0017] In any pocket coil mattress according to the present invention, the amount of adhesive used to bond the first core material to the first end face may be less than the amount of adhesive used to bond the second core material to the second end face. [Effects of the Invention]

[0018] In any of the pocket coil mattresses according to the present invention, the layer of the first core material in contact with the bag-like body is made soft, and the layer away from the bag-like body is made hard. Furthermore, the user can manually peel off at least the hard layer of the first core material from the bag-like body while the bag-like body remains fixed to the second core material. As a result, the process of peeling off the first core material and the process of tearing the bag-like body along the cutting line are performed at different times. Therefore, the force required for each of the peeling and tearing processes is reduced compared to the force required when the peeling and tearing processes are performed together. Moreover, unless force is applied in the peeling direction, the possibility of the first core material separating from the bag-like body is low, and since at least the hard layer has rigidity, the function of limiting the elastic deformation direction of the spring coil group during use is maintained. Therefore, any of the pocket coil mattresses according to the present invention have the effect of achieving both ease of disassembly at home and cushioning performance during use. [Brief explanation of the drawing]

[0019] [Figure 1] It is a schematic cross-sectional view of a pocket coil mattress according to an embodiment. [Figure 2] Fig. 2(A) is a plan view of a spring unit according to an embodiment, and Fig. 2(B) is a cross-sectional view taken along line X-X of Fig. 2(A). [Figure 3] It is a flow chart of a disassembling process of a spring unit. [Figure 4] It is an explanatory diagram illustrating a state in which a first core material is peeled off from a spring unit. [Figure 5] It is an explanatory diagram illustrating another state in which a first core material is peeled off from a spring unit. [Figure 6] It is a flow chart of a process for manufacturing a first core material. [Figure 7] It is a flow chart of a process related to adhesion of materials of a spring unit. [Figure 8] It is a table showing properties and the like of a core material of a spring unit according to an example. [Figure 9] Fig. 9(A) is a table showing properties and the like of an adhesive according to a first modification, and Fig. 9(B) is a table showing application conditions and the like of an adhesive according to a second modification. MODE FOR CARRYING OUT THE INVENTION

[0020] 1. Composition of a pocket coil mattress Hereinafter, a preferred embodiment of a pocket coil mattress according to the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic cross-sectional view of a pocket coil mattress according to an embodiment. As shown in Fig. 1, the pocket coil mattress 100 according to the embodiment includes an inner cover 100in made of non-woven fabric that houses the spring unit 1, a urethane foam 100uf placed on the inner cover 100in, and an outer cover 100out made of polyester knit fabric that houses the entire spring unit 1 and urethane foam 100uf. This pocket coil mattress 100 is compressed and roll-packed in a compression bag (not shown) and delivered to the user's home or other location of use in its packaging. When the user unrolls the mattress on a bed frame (not shown) with the urethane foam 100uf side facing up and tears the compression bag with scissors or similar, the pocket coil mattress 100 will begin to inflate and will return to its appropriate thickness after several hours to 1-3 days. At this point, the pocket coil mattress 100 will be ready for use. Subsequently, when the pocket coil mattress 100 becomes unusable, the user opens the zipper of the outer cover 200out to remove the inner cover 100in and the urethane foam, and then opens the zipper of the inner cover 100in to remove the spring unit 1. As a result, the pocket coil mattress 100 is disassembled into the outer cover 100out, the inner cover 100in, the urethane foam 100uf, and the spring unit 1. The method for disassembling the spring unit 1 will be described later.

[0021] 2. Spring Unit Configuration The configuration of the spring unit 1 will be described below. Figure 2(A) is a plan view of the spring unit according to the embodiment, and Figure 2(B) is a cross-sectional view of Figure 2(A) XX. As shown in Figures 2(A) and (B), the spring unit 1 comprises a plurality of metal spring coils 10C, 10C, ... densely arranged in a plane, a plurality of rows of bag-shaped bodies 10, 10, ..., a sheet-like first core material 11, and a sheet-like second core material 12. Hereinafter, the collection of the plurality of spring coils 10C, 10C, ... will be referred to as the "spring coil group 10G". The multiple rows of bag-like bodies 10, 10, ... are bag-shaped nonwoven fabrics that individually house multiple rows of spring coils that constitute each row of the spring coil group 10G. Each bag-like body 10 is divided into multiple housing chambers arranged in one direction by multiple welded sections 10M, 10M, ... and houses one spring coil 10C in each housing chamber. Adjacent bag-like bodies 10, 10 are fixed to each other by, for example, three rows of adhesive 20S, 20S, 20S applied in a line at different height positions, and each of the multiple rows of bag-like bodies 10, 10, ... has a cut line 101 formed around its circumference, such as a melted line by ultrasonic welding or a perforation. Therefore, the user can tear open each row of bag-like bodies 10 by hand to expose multiple spring coils 10C, 10C... The first core material 11 is a felt sheet that is bonded to the first end face 10U, which is the top of multiple rows of bag-like bodies 10,10,..., with adhesive 20U,20U,... applied in a line. The felt sheet itself has moderate cushioning and elasticity, which contributes to a comfortable sleeping experience. The second core material 12 is a felt sheet that is bonded to the second end face 10B, which is the bottom of multiple rows of bag-like bodies 10,10,... with adhesive 20B,20B,... applied in a line. This second core material 12 works in cooperation with the first core material 11 to have functions such as restricting the elastic deformation direction of the spring coil group 10G to the coil axis direction, limiting the amount of deformation of individual spring coils 10C,10C,... and maintaining the overall shape of the spring coil group 10G in a roughly rectangular parallelepiped shape. In addition to felt sheets, nonwoven fabric can also be used as the second core material 12. Furthermore, the first core material 11 of this embodiment has a two-layer structure consisting of a soft layer 11B bonded to the first end face 10U and a hard layer 11U laminated on the soft layer 11B. With the bag-like bodies 10,10,... fixed to the second core material 12, the user can manually peel off at least the hard layer 11U of the first core material 11 from the bag-like bodies 10,10,... As a result, the user can easily disassemble the spring unit 1 of this embodiment by hand as follows.

[0022] 3. Disassembly process of the spring unit The disassembly process of the spring unit 1 will now be described. Figure 3 is a flowchart of the disassembly process of the spring unit. As shown in Figure 3, the disassembly process of the spring unit 1 includes the steps of: (S11) the user manually opening the zipper of the outer cover 100out and removing the inner cover 100in and urethane foam 100uf; (S12) the user manually opening the zipper of the inner cover 100in and removing the spring unit 1; (S13) the user manually peeling off the first core material 11; (S14) the user manually tearing along the cut lines 101 of each of the bag-like bodies 10, 10, ... to expose the spring coil group 10G; and (S15) the user manually removing the spring coil group 10G. Therefore, the user can easily separate the spring unit 1 into the spring coil group 10G made of metal and the other materials. When peeling off the first core material 11 by hand (S13), it is possible to peel off the entire first core material 11 at once, as shown in Figure 4, but it is also possible that all or part of the soft layer 11B remains adhered to the bag-like bodies 10, 10, ... as shown in Figure 5. However, as will be described later, the soft layer 11B of the first core material 11 is moderately soft, so even if part or all of the soft layer 11B remains attached to the top of the bag-like bodies 10, 10, ..., it is still possible for the user to tear the cut lines 101 of the bag-like bodies 10, 10, ... by hand in the procedure for exposing the spring coil group 10G (S14).

[0023] 4. Thickness of constituent materials The following describes the conditions for the thickness of the constituent materials that are suitable for enabling the disassembly process described above. As shown in the "Thickness" column of Figure 8, for example, the thickness of the hard layer 11U is 3 mm to 3.7 mm (preferably 3.7 mm), the thickness of the soft layer 11B is 0.3 mm to 1.0 mm (preferably 0.3 mm), and the thickness of the second core material 12 is approximately the same as the thickness of the first core material 11, 3 mm to 3.7 mm (preferably 3.7 mm). Thus, in the spring unit 1 of this embodiment, it is preferable that the thickness of the soft layer 11B is kept thinner than the thickness of the hard layer 11U, and that it falls within the range of 8% to 34% of the thickness of the hard layer 11U.

[0024] 5. Peel strength of constituent materials The following describes the conditions for the peel strength of the constituent materials that are suitable for enabling the disassembly process described above. As shown in the "Peel Strength" column of Figure 8, for example, the peel strength of the hard layer 11U to the soft layer 11B is 40N to 55N (preferably 50N to 55N, more preferably 50N), the peel strength of the second core material 12 to the second end face 10B is 60N to 70N (preferably 65N), and the peel strength of the soft layer 11B to the first end face 10U is about the same as the peel strength of the second core material 12 to the second end face 10B, which is 60N to 70N (preferably 65N). Thus, in the spring unit 1 of this embodiment, the peel strength of the hard layer 11U to the soft layer 11B is kept lower than the peel strength of the second core material 12 to the second end face 10B, and it is preferable that the peel strength of the hard layer 11U to the soft layer 11B falls within the range of 57% to 92% (preferably 70% to 92%) of the peel strength of the second core material 12 to the second end face 10B.

[0025] 6. Composition of the core material The following describes a suitable core material composition for enabling the disassembly process described above. As shown in the "Composition" column of Figure 8, each of the first core material 11 and the second core material 12, which are made of felt sheets, is a mixture of a fiber component and an adhesive component. The fiber component is, for example, polyester cotton with a melting point of 160°C, and the adhesive component is, for example, a molten and cured product of polyester cotton with a melting point of 110°C. As shown in the "Adhesive Component Mixing Ratio" column of Figure 8, the adhesive component mixing ratio in the hard layer 11U of the first core material 11 is 20% to 25% (preferably 20%), the adhesive component mixing ratio in the soft layer 11B of the first core material 11 is 10% to 15% (preferably 10%), and the adhesive component mixing ratio in the second core material 12 is the same as in the hard layer 11U, 20% to 25% (preferably 20%). Thus, in the spring unit 1 of this embodiment, the proportion of adhesive components in the soft layer 11B of the first core material 11 is kept lower than the proportion of adhesive components in the hard layer 11U of the first core material 11, and it is preferable that the proportion of adhesive components in the soft layer 11U be within the range of 40% to 75% of the proportion of adhesive components in the hard layer 11U. Therefore, the soft layer 11B becomes softer than the hard layer 11U and the second core material 12.

[0026] 7. First core material production process The following describes the manufacturing process of the first core material 11 applicable to the manufacturing method of the pocket coil mattress 100 according to this embodiment. Figure 6 is a flowchart of the manufacturing process of the first core material. First, a first fiber with a relatively high melting temperature is prepared as the raw material for the fiber component, and a second fiber with a relatively low melting temperature is prepared as the raw material for the adhesive component (S21). Here, the first fiber is polyester cotton with a melting temperature of 160°C, and the second fiber is polyester cotton with a melting temperature of 110°C. Next, a lump of first fiber (polyester cotton with a melting point of 160°C) is spread out to a thickness of about 50 mm to 100 mm and placed on the conveyor line of the felt manufacturing machine. Second fiber (polyester cotton with a melting point of 110°C) is then incorporated into the cotton to create the prototype of the first core material 11. At this time, the proportion of second fiber in the layer that will become the soft layer 11B is kept lower than the proportion of second fiber in the layer that will become the hard layer 11U (S22). Next, the original shape is flattened and stretched using a hot roller at a temperature higher than the melting temperature of the second fiber and lower than the melting temperature of the first fiber (110°C to 160°C), thereby compressing it into a sheet with a thickness of approximately 3 mm to 5 mm (S23). Next, by cooling, a first core material 11 at room temperature is produced, which is a mixture of the adhesive component, which is the molten hardened product of the second fiber, and the fiber component, which is the first fiber that did not melt (S24). According to the above process, a first core material 11 can be manufactured in which a hard layer 11U is laminated on a soft layer 11B, and the peel strength of the hard layer 11U relative to the soft layer 11B is appropriately set.

[0027] 8. First variation The following describes a first modified example of the embodiment described above. The following bonding process can also be applied to the manufacturing of the pocket coil mattress 100 according to the embodiment described above. The following describes the bonding process applicable to the manufacturing method of the pocket coil mattress 100 according to the embodiment. Figure 7 is a flowchart of the process related to bonding the materials of the spring unit. Here, the case in which the bonding of adjacent bag-shaped bodies 10, 10 to each other, the bonding of the bag-shaped body 10 to the first core material 11, and the bonding of the bag-shaped body 10 to the second core material 12 are performed in parallel, but it is also possible to perform these bondings sequentially. First, prepare an adhesive with a predetermined melting temperature (S31). This adhesive is, for example, a hot-melt glue with a melting temperature of 160°C (see the "Type" column in Figure 9(A)). Next, the adhesive, heated to a predetermined temperature (160°C in this case) or close to it, is applied to the top, bottom, and both sides of the bag-shaped body 10 (S32). However, at this time, the temperature of the adhesive applied to the top of the bag-shaped body 10 is set to a temperature lower than the predetermined temperature (160°C in this case) (for example, 150°C), and the temperature of the adhesive applied to the bottom of the bag-shaped body 10 and the adhesive applied to both sides of the bag-shaped body 10 are set to the same temperature as the predetermined temperature (160°C in this case) (see the "Temperature during application" column in Figure 9(A)). Then, the multiple rows of bag-like bodies 10,10,... are bonded to each other, and the first core material 11U is bonded to the top (first end face 10U) of the multiple rows of bag-like bodies 10, and the second core material is bonded to the bottom (second end face 10B) of the multiple rows of bag-like bodies 10 (S33). Next, the adhesive is cured by cooling it through natural cooling at room temperature (S34). The adhesive applied to the top of the bag-shaped body 10 is labeled 20U in Figure 2, the adhesive applied to the side of the bag-shaped body 10 is labeled 20S in Figure 2, and the adhesive applied to the bottom of the bag-shaped body 10 is labeled 20B in Figure 2. The adhesive strength of adhesive 20U, which is heated and cured at a temperature lower than the melting temperature of 150°C, is weaker than the adhesive strength of adhesives 20B and 20S, which are heated and cured at a melting temperature of 160°C (see the "Adhesive Strength" column in Figure 9(A)). Therefore, the adhesive 20U heat-cured in the above process can appropriately suppress the peel strength of the soft layer 11B from the bag-like body 10. This reduces the possibility that the soft layer 11B will remain attached to the bag-like body 10 when peeling off the first core material 11, as shown in Figure 5, and increases the possibility that the entire first core material 11 can be peeled off at once, as shown in Figure 4. On the other hand, since both the adhesives 20B and 20S heat-cured in the above process have sufficiently high adhesive strength, they can withstand the strong pressure of the compression roll process and prevent the materials of the spring unit 1 from separating during use. Furthermore, according to the first modified example, since the peel strength of the first core material 11 to the first end face 10U is suppressed, the first core material 11 of the pocket coil mattress 100 can be a two-layer felt sheet similar to that of the embodiment, or a one-layer felt sheet consisting only of a hard layer 11U can be used, or a so-called nonwoven fabric can be used.

[0028] 9. Second variation The following describes a second modification of the above-described embodiment. In the first modification described above, the adhesive strength of the adhesive was adjusted by the temperature at which the adhesive was applied, but in the second modification, the adhesive strength is adjusted by the amount of adhesive applied. For this reason, in the second modification, the amount of adhesive 20U used to bond the first core material 11 to the first end surface 10U is kept to a minimum compared to the amount of adhesive 20B used to bond the second core material 12 to the second end surface 10B. For example, by limiting the amount of adhesive applied to the top of the bag-shaped body 10 to 80% of the amount of adhesive applied to the bottom of the bag-shaped body 10, the adhesive strength of the first core material 11 to the first end surface 10U of the bag-shaped body 10 can be limited to 80% of the adhesive strength of the second core material 12 to the second end surface 10B of the bag-shaped body 10. Specifically, as shown in the "Nozzle Diameter" column of Figure 9(B), the diameter of the nozzle for applying adhesive to the top of the bag-shaped body 10 may be set to 0.6 mm, the diameter of the nozzles for applying adhesive to both sides of the bag-shaped body 10 may be set to 0.8 mm, and the diameter of the nozzle for applying adhesive to the bottom of the bag-shaped body 10 may be set to 0.8 mm. Other application conditions may be common to the top, both sides, and bottom. Furthermore, as shown in the "Amount of Adhesive per 1m of Each Line" column of Figure 9(B), the amount of adhesive per 1m of each line may be set to approximately 6.5 g at the top of the bag-shaped body 10, approximately 8.0 g at both sides, and approximately 8.0 g at the bottom. By optimizing the relationship between the application amounts in this way, the adhesive strength of the adhesive 20U at the top of the bag-shaped body 10 can be made appropriately weaker than the adhesive strength of the adhesives 20B and 20S at the bottom and both sides of the bag-shaped body 10 (see the "Adhesive Strength" column in Figure 9(B)). Furthermore, according to the second modification, since the peel strength of the first core material 11 to the first end face 10U is suppressed, the first core material 11 of the pocket coil mattress 100 can be a two-layer felt sheet similar to the embodiment, or a one-layer felt sheet consisting only of a hard layer 11U can be used, or so-called nonwoven fabric can be used.

[0029] 10. Other variations In the first and second modified examples, either the temperature during application of the adhesive or the amount of adhesive applied was adjusted to control the adhesive strength of the adhesive. However, a combination of the temperature during application of the adhesive and the amount of adhesive applied may also be adjusted.

[0030] 11. Effects of the Embodiment As described above, in the spring unit 1 according to the embodiment, the layer of the first core material 11 in contact with the bag-shaped body 10 is a soft layer 11B, and the layer away from the bag-shaped body 10 is a hard layer 11U. Furthermore, while the bag-shaped body 10 remains fixed to the second core material 12, at least the hard layer 11U of the first core material 11 can be peeled off by hand by the user. Therefore, the step of peeling off the first core material 11 (S13) and the step of tearing the bag-shaped body 10 along the cutting line 101 (S14) are performed at different times. For this reason, the force required for each of the peeling (S13) and tearing (S14) steps is lower than the force required when the peeling (S13) and tearing (S14) steps are performed together. Moreover, unless a force is applied in the peeling direction, the first core material 11 will not separate from the bag-shaped body 10, and at least the hard layer 11U has a certain rigidity, so the function of limiting the elastic deformation direction of the spring coil group 10G during use is maintained. Therefore, the pocket coil mattress 100 including the spring unit 1 of this embodiment can achieve both ease of disassembly at home and cushioning performance during use.

[0031] 12. Others As described above, preferred embodiments and variations thereof of the present invention have been described in detail, but the present invention is not limited to these specific embodiments or variations, and various modifications and changes are possible. For example, the pattern of the cut lines 101 provided on the bag-like body 10 can be changed to other known patterns. [Explanation of Symbols]

[0032] 1 Spring Unit 10 Bag-like body 100 Pocket Coil Mattress 100in Inner Cover 100 out outer cover 100uf polyurethane foam 101 Cut line 10B Second end face 10C Spring Coil 10G Spring Coil Group 10U first end surface 11. First core material 12 Second core material 11B Soft Layer 11U hard layer 20B Adhesive 20S Adhesive 20U adhesive

Claims

1. A pocket coil mattress having a group of spring coils densely arranged on a plane, Multiple rows of bag-like bodies, each containing a plurality of spring coil rows that make up the spring coil group, A sheet-like first core material is adhered to the first end surface, which is either the top or bottom of the multiple rows of bag-shaped bodies, The device comprises a sheet-like second core material that is bonded to the second end face, which is either the top or bottom of the multiple rows of bag-shaped bodies, and which cooperates with the first core material to limit the elastic deformation of the spring coil group, The first core material has a soft layer bonded to the first end face and a hard layer laminated on the soft layer, and at least the hard layer of the first core material can be peeled off by hand from the bag-like body while the bag-like body remains fixed to the second core material. Each of the multiple rows of the bag-like bodies is provided with a pre-cut line that allows the user to tear the bag-like body by hand after the first core material has been removed to expose the group of spring coils. A pocket coil mattress with distinctive features.

2. In the pocket coil mattress according to claim 1, The thickness of the soft layer is kept smaller than the thickness of the hard layer. A pocket coil mattress with distinctive features.

3. In the pocket coil mattress according to claim 2, The thickness of the soft layer is kept within the range of 8% to 34% of the thickness of the hard layer. A pocket coil mattress with distinctive features.

4. In the pocket coil mattress according to claim 1, The peel strength of the hard layer against the soft layer is kept lower than the peel strength of the second core material against the second end face. A pocket coil mattress with distinctive features.

5. In the pocket coil mattress according to claim 4, The peel strength of the hard layer over the soft layer is kept within the range of 57% to 92% of the peel strength of the second core material over the second end face. A pocket coil mattress with distinctive features.

6. In the pocket coil mattress according to claim 5, The peel strength of the hard layer over the soft layer is within the range of 40 N to 55 N. A pocket coil mattress with distinctive features.

7. In the pocket coil mattress according to claim 1, The first core material is a mixture of fiber components and adhesive components. The proportion of adhesive components in the soft layer is kept lower than the proportion of adhesive components in the hard layer. A pocket coil mattress with distinctive features.

8. In the pocket coil mattress according to claim 7, The proportion of adhesive components in the soft layer is kept within the range of 40% to 75% of the proportion of adhesive components in the hard layer. A pocket coil mattress with distinctive features.

9. In the pocket coil mattress according to claim 1, The strength of the adhesive used to bond the first core material to the first end face is: The strength of the adhesive used to bond the second core material to the second end face is kept lower than that of the adhesive used to bond the second core material to the second end face. A pocket coil mattress with distinctive features.

10. In the pocket coil mattress according to claim 9, The amount of adhesive used to bond the first core material to the first end face is: The amount of adhesive used to bond the second core material to the second end face is kept to a minimum. A pocket coil mattress with distinctive features.

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