BUFFER SUBSTRATE AND USE THEREOF

• US 20100203788A1
• Filed: 08/27/2008
• Published: 08/12/2010
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Kuraray Company Limited
• Original Assignee: Kuraray Kuraflex Co., Ltd. (Kuraray Company Limited)
• Inventors: Koizumi, Satoshi, Muraki, Kazuhiro, Kimura, Tomoaki, Ochiai, Toru, Kiyooka, Sumito
• Granted Patent: US 9,200,390 B2
• Time in Patent Office: Days
• US Class Current: 442/327
• CPC Class Codes: D04H 1/005 Making three-dimensional articles by consolidation D04H1/22 takes precedence
• CPC Class Codes: D04H 1/02 Cotton wool; Wadding
• CPC Class Codes: D04H 1/5405 at spaced points or locations
• CPC Class Codes: D04H 1/5412 sheath-core
• CPC Class Codes: D04H 1/5414 side-by-side
• CPC Class Codes: D04H 1/5418 Mixed fibres, e.g. at least two chemically different fibres or fibre blends
• CPC Class Codes: D04H 1/544 Olefin series
• CPC Class Codes: D04H 1/545 Polyvinyl alcohol
• CPC Class Codes: D04H 1/55 Polyesters
• CPC Class Codes: D04H 1/558 in combination with mechanical or physical treatments other than embossing
• CPC Class Codes: D04H 1/74 the fibres being orientated, e.g. in parallel (anisotropic fleeces)
• CPC Class Codes: D04H 13/007 strengthened or consolidated by welding together the various components
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 442/60 Nonwoven fabric [i.e., nonwoven strand or fiber material]

Abstract

In a nonwoven fiber assembly which comprises a fiber comprising a thermal adhesive fiber under moisture and in which the fiber are entangled with each other, the fibers are bonded at contacting points of the fibers by melting the thermal adhesive fiber under moisture to distribute the bonded points approximately uniformly, thereby obtaining a buffer substrate. The buffer substrate may further comprises a conjugated fiber comprising a plurality of resins which are different in thermal shrinkage and form a phase separation structure, and the conjugated fibers may have an approximately uniform crimps having an average curvature radius of 20 to 200 μm and are entangled with the fibers constituting the nonwoven fiber assembly. The buffer substrate can be obtained by a method comprising the steps of: forming a web from the fiber comprising the thermal adhesive fiber under moisture; and subjecting the obtained fiber web to a heat and moisture treatment with a high-temperature water vapor to melt the thermal adhesive fiber under moisture for bonding the fibers. The buffer substrate has a high air-permeability, an excellent cushion property and softness.

Claims

1. A buffer substrate comprising a nonwoven fiber assembly which comprises a fiber comprising a thermal adhesive fiber under moisture and in which the fibers constituting the nonwoven fiber assembly are entangled with each other and bonded at contacting points by melting the thermal adhesive fiber under moisture to distribute the bonded points approximately uniformly.

2. A buffer substrate according to claim 1, wherein the nonwoven fiber assembly further comprises a conjugated fiber comprising a plurality of resins which are different in thermal shrinkage and form a phase separation structure, and the conjugated fibers have an approximately uniform crimps having an average curvature radius of from 20 to 200 ™

and are entangled with the fibers constituting the nonwoven fiber assembly.

3. A buffer substrate according to claim 1, wherein the bonded fiber ratio is from 1 to 45% in each of three areas and the proportion of the minimum value relative to the maximum value among the bonded fiber ratios in each of the three areas is not less than 50%,

providing that the three areas are obtained by cutting the buffer substrate in the thickness direction to give a cross section and dividing the cross section in a direction perpendicular to the thickness direction equally into three.

4. A buffer substrate according to claim 2, wherein the curved ratio of the conjugated fiber is not less than 1.3 in each of three areas and the proportion of the minimum value relative to the maximum value among the curved ratios in each of the three areas is not less than 75%,

providing that the three areas are obtained by cutting the buffer substrate in the thickness direction to give a cross section and dividing the cross section in a direction perpendicular to the thickness direction equally into three.

5. A buffer substrate according to claim 1, wherein the thermal adhesive fiber under moisture is a sheath-core structure conjugated fiber which comprises a sheath comprising an ethylene-vinyl alcohol-series copolymer and a core comprising a polyester-series resin.

6. A buffer substrate according to claim 2, wherein the conjugated fiber comprises a poly(alkylene arylate)-series resin and a modified poly(alkylene arylate)-series resin and has a side-by-side structure or an eccentric sheath-core structure.

7. A buffer substrate according to claim 2, wherein the mass ratio of the thermal adhesive fiber under moisture relative to the conjugated fiber is 90/10 to 10/90.

8. A buffer substrate according to claim 1, wherein the apparent density is from 0.01 to 0.2 g/cm³.

9. A buffer substrate according to claim 1, wherein the air-permeability is from 0.1 to 300 cm³/(cm²·

second) in accordance with a Frazier tester method, and the ratio of a 25% compression stress in the recovery behavior relative to a 25% compression stress in the compression behavior is not less than 10% in a 50% compression and recovery behavior in accordance with JIS K6400-2.

10. A buffer substrate according to claim 1, which has a sheet or plate form and an approximately uniform thickness.

11. A buffer substrate according to claim 10, wherein the fibers constituting the nonwoven fiber assembly are oriented in a direction approximately parallel to a surface direction of the buffer substrate.

12. A buffer substrate according to claim 11, which has a plurality of areas comprising a large amount of the fibers oriented in the thickness direction of the buffer substrate,

wherein the plurality of areas are arranged regularly in the surface direction of the buffer substrate.

13. A buffer substrate according to claim 12, wherein each of the plurality of areas has a hole.

14. A method for producing a buffer substrate recited in claim 1, comprising:

(a) forming a web from a fiber comprising a thermal adhesive fiber under moisture; and

(b) subjecting the obtained fiber web to a heat and moisture treatment with a high-temperature water vapor to melt the thermal adhesive fiber under moisture for bonding the fibers.

15. A method for producing a buffer substrate recited in claim 2, comprising:

(c) forming a web from a fiber comprising a thermal adhesive fiber under moisture and a conjugated fiber comprising a plurality of resins which are different in thermal shrinkage and form a phase separation structure; and

(d) subjecting the obtained fiber web to a heat and moisture treatment with a high-temperature water vapor to melt the thermal adhesive fiber under moisture for bonding the fibers and to develop a crimp of the conjugated fiber.

16. A method according to claim 14, further comprising subjecting a plurality of regularly arranged areas of a surface of the fiber web to a treatment to change the orientation directions of the fibers prior to conducting (b) or (d).

17. A buffer substrate according to claim 1, which is a substrate for a cushion.

18. A buffer substrate according to claim 17, which is a substrate for a cushion of a vehicle,

wherein the apparent density is from 0.02 to 0.2 g/cm³, and the compression recovery ratio is not less than 60%;

and the nonwoven fiber assembly comprises a conjugated fiber and has mass ratio of the thermal adhesive fiber under moisture relative to the conjugated fiber of 90/10 to 40/60 and a bonded fiber ratio of from 3 to 30% in each of three areas

providing that the three areas are obtained by cutting the nonwoven fiber assembly in the thickness direction to give a cross section and dividing the cross section in a direction perpendicular to the thickness direction equally into three.

19. A buffer substrate according to claim 1, which is a substrate for a brassiere cup.

20. A buffer substrate according to claim 19, wherein the apparent density is 0.01 to 0.15 g/cm³, the ratio of a 25% compression stress in the recovery behavior relative to a 25% compression stress in the compression behavior is not less than 20% in a 50% compression and recovery behavior in accordance with JIS K6400-2, and the bonded fiber ratio is 1 to 25% in each of three areas;

and the nonwoven fiber assembly comprises a conjugated fiber and has a mass ratio of the thermal adhesive fiber under moisture relative to the conjugated fiber of 40/60 to 10/90,

providing that the three areas are obtained by cutting the buffer substrate in the thickness direction to give a cross section and dividing the cross section in a direction perpendicular to the thickness direction equally into three.

21. A brassiere cup, which is formed from a buffer substrate recited in claim 19.

22. A buffer substrate according to claim 1, which is a buffer substrate for a shoe insole.

23. A buffer substrate according to claim 22, wherein the apparent density is from 0.03 to 0.20 g/cm³, the ratio of a 25% compression stress in the recovery behavior relative to a 25% compression stress in the compression behavior is not less than 15% in a 50% compression and recovery behavior in accordance with JIS K6400-2, and the bonded fiber ratio is from 4 to 35% in each of three areas,

providing that the three areas are obtained by cutting the buffer substrate in the thickness direction to give a cross section and dividing the cross section in a direction perpendicular to the thickness direction equally into three.

24. A shoe insole, which is formed a buffer substrate recited in claim 22.

25. A method for producing a buffer member, comprising thermoforming a buffer substrate recited in claim 1 into a predetermined shape.

26. A method according to claim 25, wherein the buffer substrate is pressed with supplying a high-temperature water vapor to the buffer substrate.

29. A method for using a buffer substrate recited in claim 1 for producing a buffer member.

30. A method according to claim 29, wherein the buffer member is a member for a cushion, a brassiere cup or a shoe insole.

31. A method according to claim 15, further comprising (e) subjecting a plurality of regularly arranged areas of a surface of the fiber web to a treatment to change the orientation directions of the fibers prior to conducting (b) or (d).

32. A brassiere cup, which is formed from a buffer substrate recited in claim 20.

33. A shoe insole, which is formed from a buffer substrate recited in claim 23.

27-28. -28. (canceled)