Technical Field

The present invention relates to a mat usable in a playroom and, more particularly, to a multilayer mat which shows excellent characteristics of noise reduction and shock absorption and both sides of which are usable.

Background Art

A mat acting as a cushion and flooring material is widely used for various applications. To be specific, the mat is used for safety in playrooms, kindergartens, household living rooms, etc. in which children or infants are present, for shock absorption at gymnasiums, yoga facilities, or the like, or for noise reduction at apartment houses, townhouses, or the like.

Such a mat is generally made from a polyvinyl chloride (PVC) or polyethylene (PE) foam. For example, a mat in which an upper layer formed by foamed PE and a lower layer formed by foamed PVC are laminated with an aqueous adhesive is disclosed in Korean Registered Utility Model No. 416915. However, this mat using the PVC material may be harmful to the health of children and infants due to a phthalate-based material used as a plasticizer in a PVC mat producing process.

Thus, customers have recently preferred a mat formed of a foamed PE material that hardly uses a toxic substance in a producing process. However, the mat using foamed PE sheets has a disadvantage in that a degree of cushioning is low compared to the mat using PVC.

To increase the degree of cushioning without using PVC, a mat in which a layer formed by thermally compressing polyester fibers between two layers formed by foamed PE and an air cap sheet layer are inserted is disclosed in Korean Registered Utility Model No. 445067. Also, a floor cushion having a shock diffusion layer with an uneven surface of an egg tray shape as an internal layer is disclosed in Korean Registered Patent No. 1308380.

However, the characteristics of the shock absorption or the noise reduction in these mats require continuous improvement and supplementation so as to meet the requests of customers who demand a further improved level.

Documents of Related Art

Patent Documents

(Patent Document 1) Korean Registered Utility Model No. 416915

(Patent Document 2) Korean Registered Utility Model No. 445067

(Patent Document 3) Korean Registered Patent No. 1308380

Disclosure

Technical Problem

Accordingly, an objective of the present invention is to provide a multilayer mat which shows excellent characteristics of noise reduction and shock absorption and both sides of which are usable. Technical Solution

To achieve the objective, the present invention provides a multilayer mat which includes two cellular polyethylene (PE) outer layers, two or more air cap sheet layers interposed between the two cellular PE outer layers, and one or more cellular PE inner layers interposed between the two or more air cap sheet layers.

Further, the present invention provides a multilayer mat which includes two cellular polyethylene (PE) outer layers having different expansion ratios, and an air cap sheet layer interposed between the two cellular PE outer layers.

Advantageous Effects

The multilayer mat according to the present invention includes cellular PE sheets and a multilayer air cap sheet layer without using a PVC material harmful to the human body, and shows excellent performance in noise reduction and shock absorption. Further, the cellular PE outer layers on both sides of the mat are formed to have different densities, and thereby both sides of the mat can be independently used for desired purposes.

Description of Drawings

FIGS. 1 to 3 are sectional views illustrating various examples of a multilayer mat according to the present invention.

FIG. 4 is a sectional view illustrating an example of an air cap sheet layer according to the present invention.

Mode for Invention

Hereinafter, the present invention will be described in greater detail.

The present invention provides a multilayer mat, which includes: two cellular polyethylene (PE) outer layers; two or more air cap sheet layers interposed between the two cellular PE outer layers; and one or more cellular PE inner layers interposed between the two or more air cap sheet layers.

The multilayer mat according to the present invention includes the two cellular PE outer layers.

A user feels a most direct (primary) sense of cushioning from the cellular PE outer layer, and it is very important to adjust shock absorptivity and elasticity of the cellular PE outer layer.

Preferably, the two cellular PE outer layers may have different expansion ratios.

The term "expansion ratio" used herein refers to a value obtained by dividing density A of a pre- foamed polymer resin by apparent density B of a post-foamed polymer resin (i.e. Expansion ratio = Density A/Density B).

As the two cellular PE outer layers have the different expansion ratios, the two cellular PE outer layers may have different densities. Thus, the user can feel different senses of cushioning from both sides of the multilayer mat of the present invention. For example, regarding both sides of the multilayer mat, the side corresponding to the cellular PE outer layer having a relatively great expansion ratio (relatively low density) may have relatively greater shock absorptivity than the other side, whereas the side corresponding to the cellular PE outer layer having a relatively small expansion ratio (relatively high density) may have relatively greater elasticity than the other side. As a result, both sides of the multilayer mat of the present invention may be used for different applications.

For example, a difference between the expansion ratios of the two cellular PE outer layers may be within a range of 3 to 15.

In one embodiment of the present invention, one of the two cellular PE outer layers has the expansion ratio of 35 to 40, and the other has the expansion ratio of 38 to 45. Therefore, the difference between the expansion ratios of the two cellular PE outer layers may be within a range of 3 to 10.

In this case, regarding both sides of the multilayer mat, one corresponding to the cellular PE outer layer whose expansion ratio is 35 to 40 is suitable as a flooring material for children who walk due to excellent elasticity, and the other corresponding to the second cellular PE outer layer whose expansion ratio is 38 to 45 is suitable for a flooring material for infants who do not walk, i.e. creep about or frequently fall down with new unsteady steps, due to excellent shock absorption. Thus, regarding both sides of the mat, the side having a suitable purpose according to whether the user of the mat is a child or an infant is selected, and can be used for that purpose.

The multilayer mat according to the present invention is provided with two or more air cap sheet layers therein. For example, the multilayer mat is provided with three or more air cap sheet layers therein.

A specific example of the air cap sheet layer structure will be described with reference to FIG. 4.

The air cap sheet layer 20 may have a base film layer 21 and an air cap layer 22 provided on the base film layer 21. The air cap layer 22 may have a configuration in which semi-hemispherical closed air caps (air cells) whose bases are disposed on the base film layer 21 are arranged in a planar shape.

The air cap sheet layer 20 may have the base film layer 21 that is thicker than a typical air cap thermal insulation sheet.

For example, the typical air cap thermal insulation sheet is designed such that a base film layer thereof has a thickness of 0.03 to 0.05 mm so as to be easily attached to glass after water is sprayed. In contrast, the base film layer 21 preferably has a thickness of 0.05 to 0.5 mm, and more preferably 0.06 to 0.1 mm.

When the thickness of the base film layer 21 is within the above range, a drawback that the air caps of the air cap layer 22 easily burst due to shocks can be compensated. Further, due to excellent shock absorption, the mat is more effective for inter- floor noise prevention.

The base film layer 21 serves to support the air cap layer 22.

The air cap sheet layer 20 may further include a protection film layer 23 provided on the air cap layer 22 unlike the typical air cap sheet. Thus, the air cap sheet layer 20 may have a configuration in which the base film layer 21 , the air cap layer 22, and the protection film layer 23 are stacked in turn.

The protection film layer 23 serves to protect the air cap layer 22, and can compensate for the drawback that the air caps (air cells) easily burst. Further, the protection film layer 23 also serves to improve workability such that the cellular PE layer and the air cap sheet layer 20 are readily bonded in the event of heat lamination.

The protection film layer 23 may have a thickness of 0.05 to 0.1 mm, and preferably 0.06 to 0.1 mm.

The multilayer mat according to the present invention includes one or more cellular PE inner layers interposed among the two or more air cap sheet layers.

For example, when a total of two air cap sheet layers are provided inside the multilayer mat, one or two or more cellular PE inner layers may be interposed between the two air cap sheet layers.

Further, when a total of three air cap sheet layers are provided inside the multilayer mat, one or two or more cellular PE inner layers may be interposed between each two of the three air cap sheet layers.

The cellular PE inner layer serves to disperse shocks and exhibit elasticity in the multilayer mat.

When a total of two or more cellular PE inner layers are provided, the expansion ratios (densities) thereof may be identical to or different from each other.

The expansion ratios (densities) of the cellular PE outer and inner layers may be identical to or different from each other.

The cellular PE inner layer may have the expansion ratio of 20 to 50, and preferably 35 to 40.

Further, when the cellular PE inner layers are provided between the air cap sheet layers in pairs, one of the two cellular PE inner layers may have the same expansion ratio as one of the two cellular PE outer layers, and the other of the two cellular PE inner layers may have the same expansion ratio as the other of the two cellular PE outer layers.

The multilayer mat according to the present invention may further include polyurethane sheets covering the two cellular PE outer layers.

The polyurethane sheets serve to prevent the stacked configuration of the multilayer mat from being collapsing and compensate for a readily sliding characteristic (slippage) of the cellular PE layers.

Further, when an unwoven fabric is laminated on a back side of each of the polyurethane sheets, the surface of the mat can be softer, or a noise caused when the user steps on the mat can be effectively reduced.

The multilayer mat according to the present invention may be produced in such a manner that the cellular PE outer layer, the air cap sheet layer, and the cellular PE inner layer are stacked in a desired configuration and are bonded using a typical method used in producing a mat, for instance, a heat lamination method. Further, the produced multilayer mat may be surrounded and sealed with the polyurethane sheets. The present invention also provides a multilayer mat that includes two cellular PE outer layers having different expansion ratios and an air cap sheet layer interposed between the two cellular PE outer layers.

Here, the air cap sheet layer may have a configuration in which a base film layer, an air cap layer, and a protection film layer are stacked. Thickness ranges and other detailed configurations of these layers are as described above. Further, specific expansion ratios and other detailed configurations of the two cellular PE outer layers are as described above. Further, the multilayer mat may further include the cellular PE inner layer and the polyurethane sheets described above. In addition, the multilayer mat may be produced by the heat lamination method as described above.

Hereinafter, the present invention will be described in greater detail based on examples.

However, the following examples are merely illustrative of the present invention, and the content of the present invention are not limited to the following examples.

Example 1

An example of the multilayer mat according to the present invention will be described with reference to FIG. 1.

The multilayer mat according to an example of the present invention may have a structure in which a first cellular PE outer layer 1 1, an air cap sheet layer 20, a cellular PE inner layer 13, a cellular PE inner layer 13', an air cap sheet layer 20, and a second cellular PE outer layer 12 are stacked in turn.

At this time, the two air cap sheet layers 20 may each have a configuration in which a base film layer, an air cap layer, and a protection film layer are stacked, and thickness ranges and other detailed configurations of these layers are as described above.

Preferably, the first cellular PE outer layer 1 1 and the second cellular PE outer layer 12 may have different expansion ratios. Further, expansion ratios of the two cellular PE inner layers 13 and 13' may be identical to or different from each other. Preferably, one cellular PE inner layer 13 may have the same expansion ratio as the first cellular PE outer layer 1 1 , and the other cellular PE inner layer 13 ' may have the same expansion ratio as the second cellular PE outer layer 12. The specific expansion ratios and other detailed configurations of the first cellular PE outer layer 1 1, the second cellular PE outer layer 12, and the cellular PE inner layers 13 and 13' are as described above.

Polyurethane sheets 30 may be further provided to cover the first cellular PE outer layer 1 1 and the second cellular PE outer layer 12. For example, the first cellular PE outer layer 11, the second cellular PE outer layer 12, and the layers 20, 13 and 13' interposed between these layers may be surrounded and sealed with the polyurethane sheets 30.

Example 2

Another example of the multilayer mat according to the present invention will be described with reference to FIG. 2.

Referring to FIG. 2, the multilayer mat may have a structure in which a first cellular PE outer layer 1 1, an air cap sheet layer 20, a cellular PE inner layer 13, an air cap sheet layer 20, a cellular PE inner layer 13', an air cap sheet layer 20, and a second cellular PE outer layer 12 are stacked in turn. At this time, the three air cap sheet layers 20 may each have a configuration in which a base film layer, an air cap layer and a protection film layer are stacked, and thickness ranges and other detailed configurations of these layers are as described above.

Preferably, the first cellular PE outer layer 1 1 and the second cellular PE outer layer 12 may have different expansion ratios. Further, expansion ratios of the two cellular PE inner layers 13 and 13' may be identical to or different from each other. Preferably, one cellular PE inner layer 13 may have the same expansion ratio as the first cellular PE outer layer 1 1 , and the other cellular PE inner layer 13 ' may have the same expansion ratio as the second cellular PE outer layer 12. The specific expansion ratios and other detailed configurations of the first cellular PE outer layer 1 1, the second cellular PE outer layer 12, and the cellular PE inner layers 13 and 13' are as described above.

Polyurethane sheets 30 may be further provided to cover the first cellular PE outer layer 1 1 and the second cellular PE outer layer 12. For example, the first cellular PE outer layer 11, the second cellular PE outer layer 12, and the layers 20, 13 and 13' interposed between these layers may be surrounded and sealed with the polyurethane sheets 30.

Example 3

Yet another example of the multilayer mat according to the present invention will be described with reference to FIG. 3.

Referring to FIG. 3, the multilayer mat may have a structure in which a first cellular PE outer layer 11, an air cap sheet layer 20, a cellular PE inner layer 13, a cellular PE inner layer 13', an air cap sheet layer 20, a cellular PE inner layer 13", a cellular PE inner layer 13"', an air cap sheet layer 20, and a second cellular PE outer layer 12 are stacked in turn.

At this time, the three air cap sheet layers 20 may each have a configuration in which a base film layer, an air cap layer, and a protection film layer are stacked, and thickness ranges and other detailed configurations of these layers are as described above.

Preferably, the first cellular PE outer layer 1 1 and the second cellular PE outer layer 12 may have different expansion ratios. Further, expansion ratios of the four cellular PE inner layers 13, 13', 13" and 13"' may be identical to or different from each other. Preferably, regarding the four cellular PE inner layers, the two cellular PE inner layers 13 and 13" may have the same expansion ratio as the first cellular PE outer layer 1 1, and the other two cellular PE inner layers 13' and 13"' may have the same expansion ratio as the second cellular PE outer layer 12. The specific expansion ratios and other detailed configurations of the first cellular PE outer layer 1 1, the second cellular PE outer layer 12, and the cellular PE inner layers 13, 13', 13" and 13"' are as described above.

Polyurethane sheets 30 may be further provided to cover the first cellular PE outer layer 1 1 and the second cellular PE outer layer 12. For example, the first cellular PE outer layer 11, the second cellular PE outer layer 12, and the layers 20, 13, 13', 13" and 13' " interposed between these layers may be surrounded and sealed with the polyurethane sheets 30.

Hereinafter, the multilayer mat according to Example 3 was evaluated with respect to noise reduction and shock absorption performance. Here, the first cellular PE outer layer 1 1 having an expansion ratio of 37 was used, and the second cellular PE outer layer 12 having an expansion ratio of 43 was used. Further, the air cap sheet layer 20 was configured such that a thickness thereof was about 3 mm and that within the thickness, a thickness of the base film layer was 0.08 mm and a thickness of the protection film layer was 0.08 mm.

For characteristics, the multilayer mat was compared with a comparative example, i.e. a mat (ALZip mat™ available from Jworld Industry Co., Ltd.) of a typical cellular PE structure that was on the market. The product to be compared was made up of a multilayer cellular PE sheet layer with no air cap sheet layer, and polyurethane sheets covering both sides of the multilayer cellular PE sheet layer.

Test Example 1 : Evaluation of noise reduction

With respect to the multilayer mat according to the present invention and the existing mat that was on the market, a floor noise reduction rate was measured as follows, and the results were summarized in Table 1.

Test institution: Korea Noise & Vibration Technology (KNV) Co., Ltd.

Test method: Tested according to Korean industrial standards below.

- KS F 2810-1 :2001 (Field measurements of impact sound insulation of floors - Part 1 : Method using standard light impact source)

- KS F 2810-2:2001 (Field measurements of impact sound insulation of floors - Part 2: Method using standard heavy impact source)

- KS F 2863-1 :2002 (Rating of floor impact sound insulation for impact source in building and of building elements - part 1 : floor impact sound insulation against standard light impact source)

- KS F 2863-2:2002 (Rating of floor impact sound insulation for impact source in building and of building elements - part 2: floor impact sound insulation against standard heavy impact source)

Table 1

As can be seen from Table 1, the multilayer mat according to the present invention has a more excellent noise reduction rate than the comparative example, and particularly shows the reduction rate above four times greater than the comparative example for the heavy impact sound.

Test Example 2: Evaluation of shock absorption

With respect to the multilayer mat according to the present invention and the mat of the comparative example, rebound resilience was determined as follows, and the results were arranged in Table 2.

Test institution: Korea Institute of Footwear & Leather Technology (KIFLT)

Test method: Tested according to Korean industrial standards below.

- KS M ISO 8307:2013 (Flexible cellular polymeric materials - Determination of resilience by ball rebound)

Table 2

As can be seen from Table 2, the multilayer mat according to the present invention shows more excellent shock adsorption performance than the mat of the comparative example. Further, it can be found that both sides of the multilayer mat according to the present invention can be used as needed because of a difference between shock adsorptivities thereof.

Description of Symbols

1 1 : first cellular PE outer layer

12: second cellular PE outer layer

13, 13', 13", 13"': cellular PE inner layer

20: air cap sheet layer

21 : base film layer

22: air cap layer

23 : protection film layer

30: polyurethane sheet