JPH09143849A - Molded cushioning material having improved resistance to repeated large deformation and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cushioning material excellent in resistance to repeated large deformation by heat molding a cut of a mat shaped mold obtained by heating the mixed multi layered web comprising polyester crimped staple fiber and polyester conjugated fusing stable fiber in a specific temperature range. SOLUTION: This mat comprises (A) 40-90wt.%, based on total formed cushioning material, of polyethylene terephthalate crimped staple fiber, (B) a sheath-core type conjugated staple fiber using polyethylene terephthalate as core and as sheath a polyester having melting point of 40-150 deg.C lower than that of polyethylene terephthalate and (C) a sheath-core type conjugated staple fiber using polyethylene terephthalate as core and a low melting temperature polyester having 25-130 deg.C lower than that of prescribed polyester as sheath. The mat uses (B) and (C) as the fusing component and the mixed web is multi layered and the crossing points of comprising fibers (A), (B) and (C) are heat fixed by pre-heating the mixed web in the range from the melting point of (C) to the melting point of (B) to obtain the mat shaped mold. Thus obtained mat is inserted in a mold after cutting and heated in the temperature range between the melting point of (B) and the melting point of (A) affording cushioning material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded cushion material using a non-elastic polyester crimped short fiber aggregate as a matrix and a method for producing the same. More specifically, the present invention relates to a cushioning material that is susceptible to repeated large deformations such as bedding and beds, and a molded cushioning material useful as a cushioning material for vehicle seats, furniture, office chairs, etc., which are molded into complicated shapes, and a cushioning material thereof. It relates to a manufacturing method.

Here, "major deformation" means that when the cushioning material undergoes compressive deformation, the thickness of the cushioning material becomes 50% or less based on the thickness of the cushioning material before deformation.

[0003]

2. Description of the Related Art Conventionally, a method of filling and molding a cushion material by stacking and placing a fiber assembly on a molding surface while scanning the surface of an air-permeable mold (Japanese Patent Laid-Open Publication No. HEI-6 (1994) -6,091).
No. 31062) is known. However, in this method, the short fiber aggregate mixed with the fusible fibers is packed in a mold, and the cushion material is molded by heat treatment. The fusible fibers are sensitive to heat and shrink. The rate cannot be lowered, and non-fusible fibers also often shrink under this heat treatment condition, so short fibers shrink during molding of the cushion material, and the molded cushion material is The phenomenon of becoming much smaller is inevitable. Further, the obtained cushioning material is inferior in durability against repeated large deformations, and is therefore not suitable for bedding, bed, etc. Further, the cushioning material is used for vehicle seats, furniture, office chairs, etc. When I was there, I was concerned about the fit and load bearing characteristics.

The present inventors have previously proposed a system using one type of fused fiber and a non-elastic polyester crimped short fiber as a matrix (International Publication No. WO91 / 19032).
Etc.). In this system, the short fiber aggregate once fusion-molded into a flat mat is cut, packed in a mold, and then fused again. Heat-fixing point (here, the heat-fixing point means a bonding portion where short fibers are fused by heat treatment) is not formed, and a low-melting point polymer having poor heat resistance such as an elastomer is fused. If this is done, the low-melting point component undergoes thermal deterioration because it is heated at least twice the melting point during cushion molding, and the resulting cushioning material suffers deterioration in durability, etc. against repeated large deformations. Such a thing is also assumed.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to prevent physical properties from deteriorating, to be durable against repeated large deformation, and to have excellent fit and load-bearing characteristics with respect to the human body and other complicated shapes. It is to provide a molded cushion material having high breathability.

It is another object of the present invention to mold the above-mentioned molded cushion material into a shape having a small shrinkage in the mold and a shape close to the size of the mold, and moreover, to locally control the density and the uneven shape arbitrarily. It is to provide a manufacturing method of the material.

[0007]

In order to solve the above-mentioned problems, the inventors of the present invention have conducted earnest studies on durability against repeated large deformation, and have made fusion bonding of heat fixing points inside the cushioning material. It has been found that the strength of the part affects the durability, and that the performance of the cushion material as a whole is inferior if only the strength is increased. Furthermore, the present inventors have made it possible to improve the performance of the cushioning material as a whole by interspersing heat-bonding points of appropriate strength and a small amount of fusion-bonded portions of relatively high strength in the cushioning material. The present invention has been investigated and the present invention has been accomplished.

That is, according to the present invention, in a molded cushion material having a matrix of the non-elastic polyester crimped short fiber (A) aggregate, the short fiber (A) aggregate is 40 based on the weight of the molded cushion material. ˜90% by weight, and at least two of the fusible short fibers (B) and the fusible short fibers (C) shown in (1) and (2) below are dispersed as fusion components. When mixed, the molding cushioning material has thermal fixation points scattered as shown in the following (d) to (h), and the fusion bond rupture strength at the thermal fixation points (e) is heat fixation. Provided is a molded cushioning material having improved durability against repeated large deformation, which is characterized by having a breaking strength higher than that at point (d).

(1) A short fiber (B) in which at least the polymer (b) having a melting point of 40 to 150 ° C. lower than the melting point of the non-elastic polyester polymer constituting the short fiber (A) is exposed on the surface.

(2) A short fiber (C) in which a polymer (c) having a melting point 25 to 130 ° C. lower than the melting point of the polymer constituting the short fiber (B) is exposed at least on the surface.

(D) Thermal fixing point of the short fibers (A) and the short fibers (B).

(E) Thermal fixing point of the short fibers (A) and the short fibers (C).

(F) Thermal fixing point of the short fibers (B) and the short fibers (C).

(G) Thermal fixing point between the short fibers (B).

(H) Thermal fixing point between the short fibers (C).

Further, according to the present invention, in the method for producing a molded cushion material using a non-elastic polyester crimped short fiber (A) aggregate as a matrix, the non-elastic polyester crimped short fiber (A) is used as a molded cushion material. 40 to 90% by weight based on the weight, and the fusible staple fibers (B) and fusible staple fibers (C) shown in (1) and (2) below, respectively.
And at least three of them are webbed, and a plurality of them are laminated, and the melting point of the polymer (c) in the short fibers (C) is higher than the melting point of the polymer (b) in the short fibers (B). The mat-shaped molded product obtained by pre-heat-treating at the temperature of 10 to form the heat-fixing points shown in (e), (f) and (h) below is cut and packed in a mold, and then the short fiber (B In (), the heat treatment is performed at a temperature not lower than the melting point of the polymer (b) and lower than the melting point of the polymer forming the short fibers (A) to form the heat fixing points shown in the following (d) and (g). (E), (f) and (h) are molded so as to increase the rupture strength of the fusion-bonded portion at the heat-fixing point, and a molded cushioning material having improved durability against repeated large deformations. Can be provided.

(1) A short fiber (B) in which at least the polymer (b) having a melting point of 40 to 150 ° C. lower than the melting point of the non-elastic polyester polymer constituting the short fiber (A) is exposed on the surface.

(2) A short fiber (C) in which a polymer (c) having a melting point lower than that of the polymer constituting the short fiber (B) by 25 to 130 ° C. is exposed at least on the surface.

(D) Thermal fixing points of the short fibers (A) and the short fibers (B).

(E) A heat fixing point between the short fibers (A) and the short fibers (C).

(F) Thermal fixing point of the short fibers (B) and the short fibers (C).

(G) Thermal fixation point between the short fibers (B).

(H) Thermal fixing point between the short fibers (C).

In the present invention, the non-elastic polyester crimped short fibers (A) are polyethylene terephthalate,
Short fibers made of polybutylene terephthalate, polyhexamethylene terephthalate, polytetramethylene terephthalate, poly-1,4-dimethylcyclohexane terephthalate, polypivalolactone or copolymer esters thereof, and blended products of these short fibers, or the above Examples thereof include composite short fibers made of two or more kinds of polymers, and the cross-sectional shape of the short fibers (A) may be circular, flat, irregular or hollow.

Since the short fibers (A) are fused with the fusion components of the short fibers (B) and the short fibers (C) to form a matrix in the cushion material, the short fibers (A) alone are bulky. In addition, it is necessary to exhibit resilience.

Here, the bulkiness (measured in accordance with JIS L-1097) is 50 c under a load of 0.5 g / cm ^2.
m ³ / g or more, 20 cm ³ / under a load of 10 g / cm ²
It is preferably g or more, and more preferably 60 cm ³ / g or more and 25 cm ³ / g or more, respectively. When the bulkiness is low, the problem that the obtained fiber-formed cushion material has low elasticity and compression repulsion becomes remarkable.

The fineness is preferably in the range of 3 to 500 denier, more preferably 8 to 200 denier. When the fineness is less than 3 denier, the bulkiness is not exhibited, and the cushioning property and the repulsion force become poor. Further, when the fineness exceeds 500 denier, it is difficult to make the short fibers into a web, and the number of the short fibers (A) in the obtained molded cushion material becomes too small, resulting in poor cushioning properties.

Further, the number of crimps is preferably 4 to 25 crimps / inch, and the crimp degree is preferably 20 to 40%. If the number of crimps and the degree of crimping are less than the above lower limits, the web becomes less bulky and web formation becomes difficult, which is not preferable. The resulting cushioning material also has poor resilience and only low durability. On the other hand, if the number of crimps or the degree of crimp exceeds the above upper limit, the bulkiness of the web is difficult to be obtained, and only a high-density cushioning material can be obtained, or the entanglement of the fibers is strong when the web is formed, and the fibers are streaky. It is not preferable because it causes unevenness. These crimped short fibers may be produced by any method such as indentation crimping and spiral crimping.

In the present invention, the short fibers (B) are polyester short fibers (A) used together in the cushion material.
A low-melting polymer (b) having a melting point of 40 to 150 ° C. lower than the melting point of the polymer constituting the above is a short fiber disposed on at least a part of the surface of the short fiber, and at least the short fiber ( B) It is necessary that at least a part of the low melting point polymer (b) existing on the surface can be melted and fused with the short fiber (A). If this difference in melting point is 40 ° C. or less, the temperature for heat treatment will be close to the melting point of the polymer constituting the inelastic polyester crimped short fiber (A), and the physical properties and crimp characteristics of the short fiber (A) will be described. Deteriorates, resulting in poor cushioning performance and large shrinkage during molding.

Examples of such so-called fusible short fibers include fibers made of a copolymerized polyester polymer, a thermoplastic elastomer polymer, a polyolefin polymer, a polyvinyl alcohol polymer, and the like.

In particular, a composite type short fiber comprising at least the above-mentioned polymer component having a low melting point and a polymer component having a higher melting point as constituent components is preferable because it is excellent in shape retention stability and moldability, The composite form is preferably a side-by-side type, a core-sheath type, an eccentric core-sheath type, etc.,
In the short fiber (B), a cross-sectional form in which a low melting point polymer as a fusion component is exposed on at least a part of the surface of the short fiber is preferable.

In the present invention, the short fibers (B) are blended in the production of the fiber-molded cushion material, and are a fusion component for forming the cushion material.
The denier is preferably 2 to 150 denier, and particularly preferably 4 to 100 denier. When the denier is small, the number of heat fixing points in the cushion material increases too much, and the cushioning property is difficult to be obtained. On the other hand, if it is too large, the number of heat fixing points is too small, the repulsion property is too low, and the cushion material is likely to be scattered during use. The cut length of the short fibers (B) is 3
It is preferable that the number of crimps is 8 to 255 mm and the number of crimps is 4 to 50 pieces / inch. If it is out of this range, it becomes difficult to mix cotton and it is difficult to form a web. Furthermore, the cushioning performance and compression durability of the molded cushioning material also deteriorate.

The cushioning material of the present invention is repeatedly subjected to compressive deformation after molding, and when the amount of compression, that is, the amount of deformation is large (for example, 50% of the thickness), for example, when it is used for cushioning or the like. It is necessary that the heat fixing point is easily deformed when a deforming stress is applied, and when the deforming stress is eliminated, it is easy to return to the original position without leaving any distortion.

When a large amount of deformation is applied to the molded cushion material, the heat fixing point composed of the short fibers (A) and the short fibers (B) constituting the cushion material changes in angle or stretches, The polymer at the heat-fixed point is required to have a characteristic of being largely deformed and recovered due to deformation such as twisting.

Therefore, the heat-fixing point is preferably composed of a thermoplastic elastomer having a large fracture elongation and good elongation recovery characteristics, and the mating matrix and the short fibers (A) to be heat-fixed are non-elastic polyester type. A polyester elastomer is particularly preferable because it is made of a polymer.

The elastic polyester elastomer is a polyether ester block copolymer obtained by copolymerizing thermoplastic polyester as a hard segment and poly (alkylene oxide) glycol as a soft segment, more specifically, terephthalic acid and isophthalic acid. acid,
Aromatic dicarboxylic acids such as phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene 2,7-dicarboxylic acid, diphenyl-4,4-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and sodium 3-sulfoisophthalate.
From an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, succinic acid, oxalic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid or the like, and / or an ester-forming derivative thereof At least one selected dicarboxylic acid and an aliphatic diol such as 1,4-butanediol, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, or the like, or 1,1-cyclohexanedimethanol,
At least one diol component selected from alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethanol, or ester-forming derivatives thereof, and polyethylene glycol having an average molecular weight of about 400 to 5,000. , Poly (1,2-propylene oxide) glycol, poly (1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, copolymers of ethylene oxide and tetrahydrofuran, etc. Examples of the terpolymer include at least one of the above poly (alkylene oxide) glycols.

Among them, the thermoplastic elastomer is made of polybutylene terephthalate as a hard segment in view of fusion property with the non-elastic polyester crimped short fiber (A), temperature characteristics, strength and physical properties. A block copolymerized polyether polyester having methylene glycol as a soft segment is preferable.

At this time, in the polyester portion constituting the hard segment, the main acid component is terephthalic acid,
Most preferred is polybutylene terephthalate having a butylene glycol component as a main diol component. of course,
A part (usually 30 mol% or less) of this acid component may be replaced with another component, and similarly, a part of the glycol component may be replaced.

Further, the polyether component constituting the soft segment may be a polyether substituted with a dioxy component other than tetramethylene glycol. It should be noted that various stabilizers, ultraviolet absorbers, thickeners, branching agents, matting agents, colorants, and other various modifiers / function-imparting agents are also added to the elastomer as required. Good.

In the present invention, the short fibers (C) have a low melting point of 25 to 130 ° C. lower than the melting point of the polymer (b) in the short fibers (B) used together as a fusion component in the cushion material. The polymer (c) is a short fiber arranged on at least a part of the surface of the short fiber, and at least a part of the surface is melted by preheat treatment, and the non-elastic polyester crimped short fiber (A) or the short fiber (B ) And short fibers (C) that can be fused to each other.

When the difference in melting point is 25 ° C. or less, the temperature for the preliminary heat treatment becomes close to the melting point of the polymer (b) in the short fibers (B), and the physical properties and shortness of the polymer (b) are short. The crimp characteristic of the fiber (B) is deteriorated.

The low melting point polymer (b) as a fusing component which constitutes such a so-called fusible short fiber is a copolyester type or a heat stabilizer or an ultraviolet absorber for strengthening heat resistance. There are thermoplastic elastomers, polyolefin-based polymers and copolymers, polyvinyl alcohol-based polymers, etc. In particular, the composite short fibers having the above-mentioned low melting point polymer as at least one constituent are preferable because they are excellent in shape retention stability and moldability. The form of the composite short fibers is preferably a side-by-side type, a core-sheath type, an eccentric core-sheath type or the like. Of course, it is necessary that the low melting point polymer has a cross-sectional shape that is exposed on the surface.

Among them, it is preferable that the counterpart short fibers at the time of fusion bonding are mainly made of polyester type polymers, and therefore, as the low melting point polymer, copolymerized polyester type polymers or thermoplastic polyester type elastomers are preferable, In terms of handling, a copolyester is particularly preferable from the viewpoint of little heat deterioration.

In the present invention, the mixing ratio of the short fibers (B) and (C) in the molded cushion material is preferably 10 to 60% by weight based on the weight of the molded cushion material. When the mixing ratio of the short fibers (B) and (C) is less than 10% by weight, the number of heat fixing points in the cushioning material becomes too small, and the bonding strength is weak, which will be described later, even after the initial fusion treatment. The handleability of the cushion material is poor,
It is not preferable because the cushioning property deteriorates.

Further, there are problems that the compression repulsion is too low and the compression durability is poor even after the strong fusion treatment described later, which is performed after the cushion material is filled in the mold. On the contrary, if the mixing ratio is too large, the number of heat fixing points in the molded cushion material is too large even after the heat treatment, and only a cushion material having a hard texture can be obtained.

In addition, the mixing ratio of the short fibers (B) and the short fibers (C) requires that the cushioning characteristics are manifested due to the heat fixing point involved with the short fibers (B) that fuse at high temperature.
The heat fixing points involved with the short fibers (C) having a strong bond breaking strength must be small and scattered in order to exhibit the durability against large deformation due to compression. Therefore, the short fibers (B) It is necessary that the mixing ratio of C is higher than the mixing ratio of the short fibers (C).

In the present invention, as the constitution of the molded cushion material, the density at which the cushioning property is exhibited is as follows.
In the range of ^{0.015g / cm 3 ~0.150g / cm 3} , the thickness of the cushion material, more preferably 2 cm.
If the density is less than the above range, the resilience and compression durability will be poor, and if the density is too large, the heat fixing points will be too many and will be too hard.

Next, the method for producing the molded cushion material of the present invention will be described. First, at least three members of a non-elastic polyester crimped short fiber (A), a short fiber (B) and a short fiber (C) are mixed and opened with a card or the like to form a web, and then a predetermined amount of web is laminated. Then, sandwich the laminated web etc. on the flat plate composed of punching plates and the conveyor with the caterpillar type upper and lower punching plates,
Alternatively, it is mounted on a net without being compressed, and is heat-treated at a temperature not lower than the temperature at which the polymer (c) forming the short fibers (C) causes fusion and lower than the melting point of the polymer (b) forming the short fibers (B). Is carried out to form heat fixing points (e), (f) and (h) to obtain a mat-shaped molded body having a predetermined thickness.
The thickness and density are designed according to the desired shape and thickness of the cushion material to be compressed and molded, but it is designed to have a desired density and shape by stacking about 3 to 10 sheets. Is preferred.

Further, the preliminary heat treatment time must be 1 minute or more and 10 minutes or less. If the heat treatment time is 1 minute or less, the polymer (c) is difficult to melt, and the heat fixing point involving the short fibers (C) cannot be formed. On the contrary, if the heat treatment time exceeds 10 minutes, the polymer (c) is not melted. Is deteriorated by heat, and the fracture strength of the fusion-bonded portion at the heat-fixing point where the short fibers (C) participate is reduced.

Next, after the mat-shaped molded product cut so that the density can be adjusted in the mold shape and the partial portion is packed in the mold, the melting point of the polymer (b) constituting the short fiber (B) is not less than the melting point of the polymer (b). It is necessary to perform heat treatment at a temperature lower than the melting point of the polymer constituting (A). The heat fixing point involving the short fibers (C) is that the low melting point polymer constituting the short fibers (C) is aggregated by the fusion treatment for strong bonding at high temperature by thermoforming in the mold. By doing so, a stronger and tougher heat-fixing point can be formed. However, if the melting point difference between the constituents of the short fibers (C) and the short fibers (B) is small, or if the mixing ratio of the short fibers (C) is greater than the mixing ratio of (B), the mat The shaped body is unlikely to be deformed into the shape inside the mold, and there is a gap in the shaped cushioning material, which is not preferable. In addition, since the polyester-based elastomer or the like which is preferable as a constituent component of the short fibers (B) does not have very high thermal stability, the difference in melting point is small and it is not preferable to be repeatedly exposed to a high temperature close to the melting point.

Here, when the temperature of the preliminary heat treatment is too low, the free shrinkage of the short fibers (A) and the short fibers (B) does not occur sufficiently. Since there is a problem of causing heat shrinkage in the above, a relatively high heat treatment which is not higher than the melting point of all the constituent components of the short fiber (B) and is not separated from the melting point by 100 ° C. or more is preferable.

Further, it is necessary that the heat treatment time is 1 minute or more and 40 minutes or less. If the heat treatment time is 1 minute or less, the polymer (b) is difficult to melt, and the short fibers (B)
The rupture strength of the fusion-bonded portion at the heat-fixing point, which is associated with, becomes too low. On the contrary, when the time exceeds 40 minutes, the polymer (a) undergoes thermal deterioration, and it is difficult to increase the rupture strength of the fusion-bonded portion at the heat-fixing point where the short fibers (C) participate. Will be reduced to.

A plurality of short fibers may be used for each of the short fibers (B) and (C). For example, as the polymer (c) constituting the short fibers (C), polymers (c1) and (c2) having different melting points are prepared (melting point of (c1) <melting point of (c2)), and each of the polymers ( Short fibers in which c1) is arranged on a part of the fiber surface and short fibers in which the polymer (c2) is arranged on a part of the fiber surface may be mixed and used. Similarly, as the polymer (b) constituting the short fibers (B), polymers (b1) and (b2) having different melting points are prepared (melting point of (b1) <melting point of (b2)), and the polymers are respectively Short fibers in which (b1) is arranged on a part of the fiber surface and short fibers in which the polymer (b2) is arranged on a part of the fiber surface may be mixed and used. The preliminary heat treatment temperature in this case is equal to or higher than the melting point of the polymer (c1) and lower than the melting point of the polymer (b1).

By forming heat fixing points by preliminary heat treatment, scissors and Thomson blades can be used to easily cut into a number corresponding to the shape and density of the mold, and it is easy to handle and mechanically grip, It will be easier to pinch and move. The mat-shaped molded body thus obtained is cut into a thin sheet-shaped slice of the cushion material (FIG. 1) molded into the final product, as shown in FIG.

In a simple case, there is a method of cutting into slices in contour lines. Of course, it may be cut in the state of being sliced in the vertical direction or the curved surface, or a combination thereof. Furthermore, the shape may not be the same, but the shape may be changed to some extent depending on the type of mat-like molded product used, the shape of the cushioning material to be obtained, and the physical properties.

The mat-shaped molded product cut in this way is changed in the number of laminated layers or arranged in the partial part in consideration of different densities in the cushion material to be molded, and the lower mold (FIG. ) Is filled with the cut mat-shaped molded body, then compressed and covered with an upper mold (Fig. 3), and then under strong fusion conditions, that is, at a temperature at which the constituent components of the short fibers (B) can be melted. , Forming all of the previously mentioned thermal fixation points.

In this way, a molded cushion material is manufactured. Before the cut mat-shaped molded body is stacked and packed in the lower mold, a fiber aggregate web covering the surface of the molded cushion material is provided on the inner surface of the mold. It is preferable to spread it. The fiber assembly web is constituted by including the non-elastic polyester crimped short fibers (A) and the short fibers (B) and / or the short fibers (C) used in the present invention,
It is preferable to use them without fusion.

Since the fiber assembly web is not fused, it can easily follow a complicated mold shape, and in particular, it can be covered along the inner surface of the mold by means such as air suction from the lower part of the lower mold (FIG. 4). Can be done. By providing such a fiber coating layer, the molded cushion material is less likely to undergo delamination, and the laminated end faces are invisible, so that the appearance of the surface can be significantly improved. Of course, this fiber assembly web may be fused to improve the handling property.

Further, the composition of the fiber aggregate web is such that it becomes the surface of the molded cushion material, so that the mixing ratio of the short fibers is changed in order to improve the abrasion resistance, and the denier is changed.
It may be carried out as desired, for example, by changing the constitution of the fiber, or by making the surface a flameproof or flameproof aggregate.

In the manufacturing method of the present invention, short fiber aggregates in which mat-like molded bodies are laminated and arranged in the lower mold are compressed, and the upper mold is covered with a lid. Although fusion-integration molding is performed, this processing condition forms a strong and tough heat-fixing point at the entanglement point where the short fibers (C) participate. At the temperature at which the constituent components of the short fibers (C) melt, the low melting point polymer was under the condition that strong aggregation did not occur at the entanglement point where the short fibers (C) participate. A strong and tough bond point is formed by the high temperature conditions such that the constituents melt.

A plurality of short fibers may be used for each of the short fibers (A) and (B). For example, as the polymer (b) constituting the short fibers (B), polymers (b1) and (b2) having different melting points are prepared (melting point of (b1) <melting point of (b2)), and each of the polymers ( Short fibers having B1) arranged on a part of the fiber surface and short fibers having polymer (b2) arranged on a part of the fiber surface may be mixed and used.

Similarly, polymers (a1) and (a2) having different melting points are prepared as the polymer (A) constituting the short fibers (A) (melting point of (a1) <melting point of (a2)), Short fibers in which the polymer (A1) is arranged on a part of the fiber surface and short fibers in which the polymer (A2) is arranged on a part of the fiber surface may be mixed and used. The heat treatment temperature in this case is equal to or higher than the melting point of the polymer (b1) and lower than the melting point of the polymer (a1).

The molded cushion material thus heat-treated is cooled and then taken out from the mold to obtain a molded cushion material. The above method is a complicated molding method, but when molding a flat mat,
The same applies when the thickness is increased again after the mat-shaped molded body is first obtained.

Of course, it is possible to heat-treat the constituent components of the short fibers (B) by performing the heat treatment only once, and in this case as well, the heat fixing point is the same as the entanglement point where the short fibers (C) participate. Can bond more strongly than the heat-fixing point where the short fiber (B) participates and can be made stronger against large deformation, and the cushioning property is contributed by the heat-fixing point where the short fiber (B) participates. However, in this method, the molding cushion material shrinks during the heat treatment in the mold.

In the manufacturing method of the present invention, the molded cushion material is further compressed to remove heat-fixing points that are weak against compression and heat-fixing points that interfere with cushioning properties.
It is preferable to stabilize the physical properties by heat treatment again.

[0066]

In the molded cushion material of the present invention, a small amount of tough heat-fixing points are scattered in addition to the heat-fixing points having appropriate strength, so that the durability against repeated large deformation is improved. The density and uneven shape can be controlled locally in the molded cushion material, and it has excellent fit and load-bearing characteristics for the human body and other complicated shapes, and has high air permeability. It can be recycled, and smoke and smoke produced by incineration are less toxic. Therefore, the molded cushion material of the present invention is 3
It is optimal as a molded cushion material having a dimensional shape or a shape other than a flat plate shape, for example, a molded cushion material such as a vehicle seat, a furniture cushion, an office chair cushion material, and a pillow.

According to the method for producing a molded cushioning material of the present invention, a 100% thermoplastic fiber is used to cut a mat-shaped molded body which is fused and easy to handle, and the number of laminated layers is changed at a partial portion in the mold. And then heat-treated again at a higher temperature to produce a molded cushion material having a tough heat-fixing point and a fusion-bonded portion, and a heat-fixing point effective for cushioning. That is, the molding cushion material can be molded in a shape close to the mold dimension by reducing shrinkage in the mold. Further, in the case of industrial production, since the accuracy of repetition is good, there is no problem even if the machine is automated.

[0068]

The present invention will be described more specifically with reference to the following examples. The evaluation items in the examples were evaluated according to the following methods.

Number of crimps and degree of crimp: Measured in accordance with JIS L-1015.

Cushion material density (g / cm ³ ): A part of the molded cushion material was cut into a rectangular parallelepiped shape and weighed (g)
And the thickness (mm) was measured with a load plate having a load of 0.5 g / cm ² , and then calculated from the volume (cm ³ ).

Hardness (kgf): 25% compression hardness according to JIS K-6401 was used. For ordinary cushion material use, there is no practical problem if the weight is 20 to 30 kg.

Melting point: thermal differential analyzer 990 type (Du Po
(manufactured by NT Inc.) was used and the temperature was raised at 20 ° C./min to measure the melting peak. If the melting temperature cannot be measured accurately, use a trace melting point measuring device (Yanagimoto Seisakusho) to measure about 3 g.
This polymer was sandwiched between two cover glasses and lightly pressed with tweezers, and the temperature was raised at a temperature rising rate of 20 ° C./min to observe the thermal change of the polymer. At that time, the temperature at which the polymer softened and started to flow (softening point) was taken as the melting point. Compressive residual strain: Measured according to JIS K-6401.

80,000 times compression residual strain: JIS K-640
It measured based on 1. 80,000 times compression residual strain is 12%
If it is below, there is no problem in practical use.

80,000 compression hardness retention rate: Initially precompressed at 75% and then compressed again at 25% and subjected to 80,000 repetitive compressions according to JIS K-6401. The compressive stress (F1) after leaving for 30 minutes, pre-compressing 75% and then compressing 25% again was calculated based on the following formula.

[0075]

## EQU1 ## [(F1 / F0) × 100 (%)] The 80,000-time compression hardness retention ratio may be 50% or more.

Bulkiness of Web: JIS L-1097
It measured according to.

Breaking strength of fusion-bonded portion at heat-fixing point: While observing the inside of the molded cushion material with a microscope, short fibers intersected at about 90 ° among the entanglement points (a representative example is shown in FIG. 6). Two short fibers were sampled including a fusion-bonded portion, and the fibers were held at the heat fixing point in the center, gripped at a nip length of 2 mm, and pulled at a speed of 2 mm / min.
Tenacity (g) was measured and calculated by dividing by the average De of two fibers. The number of n was set to 10, and the average was calculated to obtain the fusion bond breaking strength of the fiber.

[Example 1] Reaction of an acid component obtained by mixing dimethyl terephthalate and dimethyl isophthalate at 80:20 (mol%) with a glycol component at 3:97 (mol%) of diethylene glycol and tetramethylene glycol. Then, a low melting point polyester polymer having a melting point of 192 ° C. was obtained. The intrinsic viscosity of this low melting point polymer is 0.9
It was 0.

An eccentric core-sheath type in which the low melting point polyester is placed in the sheath portion and polyethylene terephthalate obtained by a conventional method is placed in the core portion, the weight ratio of the core portion to the sheath portion is 50:50. A composite fiber was obtained.

The obtained fiber was stretched 2.5 times to obtain 100
After drying and crimping at ℃, apply an oil agent and fiber length 64
It was cut into mm. The resulting short fibers had a denier of 9 denier, a crimp number of 15 / inch, and a crimp degree of 27%. This composite short fiber was used as a short fiber (B).

Next, 6 parts of terephthalic acid and isophthalic acid were added.
A copolyester was obtained from an acid component mixed at 0:40 (mol%) and a diol component mixed at 85:15 (mol%) of ethylene glycol and diethylene glycol. The intrinsic viscosity of this polyester was 0.78. Although the melting point was not clear, it softened at around 110 ° C. and started flowing, so 110 ° C. was taken as the softening point.

This polymer was placed in the sheath component, polyethylene terephthalate was placed in the core, and a composite fiber having a weight ratio of the core to the sheath of 50:50 was obtained by a conventional method. This composite fiber was used as a short fiber (C).

Next, polyethylene terephthalate crimped short fibers (A) (14 denier, fiber length 6) obtained by a conventional method
4 mm, number of crimps of spiral crimp by anisotropic cooling 9 / inch, crimp degree 30%, bulkiness 79 cm ³ / g under load of 0.5 g / cm ² under load of 10 cm ³ / g In 3
4 cm ³ / g, hollow cross-section, melting point 256 ° C.) 65 parts by weight, short fibers (B) 20 parts by weight, short fibers (C) 4 parts by weight, and after webbing with a card, a laminated web was formed. Obtained.

This web had a thickness of 5 cm and a density of 0.
It was sandwiched between flat air-permeable molds so as to have a pressure of 010 g / cm ² , pressurized and heated in a hot air oven at 160 ° C. for 2 minutes, and then cooled, and then a mat-shaped molded product (flat fused fiber molded product). ), And then punched with a Thomson blade so as to form a chair cushion shape as shown in FIG. 7. It was presumed that the punched mat-shaped molded article had good handleability, was easy to work with, and was easy to mechanize. A predetermined number of the punched mat-shaped moldings are stacked at a predetermined position in the mold, compressed from above and below by a mold heated at 210 ° C. for 5 minutes, cooled, and then taken out from the mold, and the molding cushion shown in FIG. I got the material.

In the obtained molded cushion material, the density of the sitting portion was 0.050 g / cm ³ , and the density of the edge portion was 0.060 g / cm ³ . Further, it was estimated that the obtained molded cushion material had almost no gap with the inside of the mold, and the shrinkage during thermoforming was extremely small. In the obtained cushion material, the fusion bond rupture strength at the heat fixing point (d) was 0.8 g / de, the strength at the heat fixing point (e) was 1.0 g / de, and the heat fixing point ( The intensity of f) is 1.9.
g / de, the strength of the heat fixing point (g) is 1.3 g / d
and the strength at the heat fixing point (h) was 0.6 g / de.

The obtained molded cushion material was cut out and the compression durability of the sitting portion was measured. As a result, the 25% hardness was 18 kg, the 80,000-time compression residual strain was 8%, and the 80,000-time compression hardness retention rate was 90%.

Comparative Example 1 In Example 1, except that the short fibers (C) were not used, 24 parts by weight of the short fibers (B) were used, and the laminated web obtained without heat treatment was punched with a Thomson blade. Was subjected to the same operation as in Example 1 to obtain a molded cushion material.

However, it was estimated that the punchability using the Thomson blade was poor, and the punched laminated web was poor in handleability, and mechanization was difficult. Further, it was estimated that the shape of the obtained cushioning material had a gap with the inside of the mold and had a large shrinkage. The obtained cushion material has a density of 0.050 g / cm ³ , a 25% hardness of 18 kg, a residual strain of 80,000 times compression of 10%, and a compression hardness retention rate of 80,000 times of 81%.
And, it was a product having inferior performance as a cushioning material. The strength of the heat fixing point (d) was 0.7 g / de, and the strength of the heat fixing point (g) was 1.2 g / de.

Example 2 Polybutylene terephthalate obtained by reacting an acid component obtained by mixing terephthalic acid and isophthalic acid at 80:20 (mol%) with butylene glycol, and polytetramethylene glycol (molecular weight: 2000) and 40: 6 based on the weight of the polymer.
A block copolymerized polyether polyester elastomer was obtained by heating and reacting so that the proportion became 0 (% by weight).

The melting point of this thermoplastic elastomer is 157.
° C. Place this thermoplastic elastomer in the sheath,
Polybutylene terephthalate (melting point 224 ° C.) was placed in the core, and spinning was carried out by a conventional method so that the weight ratio of the core to the sheath was 50:50. This composite fiber is an eccentric core-sheath composite fiber. After this fiber was drawn 2.0 times, it was dried and crimped at 80 ° C., an oil agent was applied, and the fiber was cut to a length of 64 mm.

The composite fiber thus obtained had a denier of 9 denier, a crimp number of 13 / inch, and a crimp degree of 30%.
Met. This composite fiber was used as a short fiber (B).

Next, terephthalic acid and isophthalic acid were mixed with 6
The acid component mixed at 0:40 (mol%) and the diol component mixed at 85:15 (mol%) of ethylene glycol and diethylene glycol were reacted to obtain a copolyester. The intrinsic viscosity of this polymer was 0.78. Although the melting point is not clear, it softened at around 110 ° C. and started flowing, so 110 ° C. was taken as the softening point.

This polymer was placed in the sheath of the composite fiber,
Polyethylene terephthalate was placed in the core, and a core-sheath type composite fiber having a weight ratio of the core to the sheath of 50:50 was obtained by a conventional method. This core-sheath type composite fiber was used as a short fiber (C).

Then, polyethylene terephthalate crimped short fibers (A) obtained by a conventional method (14 denier, cut length 64 mm, number of crimps of anisotropic cooling spiral crimps / inch, crimping degree 30%, Density of 7 under a load of 0.5 g / cm ^2.
Density 34 cm under load of 9 cm ³ / g, 10 cm ³ / g
³ / g, hollow cross section, melting point 256 ° C.) 65 parts by weight, short fibers (B) 27 parts by weight and short fibers (C) 8 parts by weight were mixed,
A card was webbed and laminated to obtain a laminated web. This laminated web has a thickness of 5 cm and a density of 0.01
It was sandwiched in a flat plate-shaped air-permeable mold so as to have a weight of 5 g / cm ³ , pressurized and heated for 2 minutes in a hot air oven at 140 ° C., and then cooled to obtain a mat-shaped molded body. The fracture strength of the fusion-bonded portion at the heat-fixing point (e) in this mat-like molded product was 0.2 g /
The strength at de and the heat fixing point (h) was 0.4 g / de.

Subsequently, as shown in FIG. 1, the above mat-shaped molded body was press-cut with a Thomson blade so that the cushion material 1 to be molded had a sliced shape. This cutting operation had a good cutting property and could be easily cut as compared with the laminated web which was not fused. Further, the nonwoven fabric obtained by needle punching the laminated web before the fusion treatment (4 in FIG. 5) (density, 100 g / cm ³ ).
Was set on the inner surface of a three-dimensional upper and lower molds (3 in FIG. 5) made of a punching plate having air permeability and covered by air suction. Since the fibers of this web were not bonded to each other, the inside of the three-dimensional mold could be easily covered along the web without cracks or gaps.

Subsequently, inside the lower mold covered with the web, the cut and fused mat-shaped molded body (2 in FIG. 5) was laminated in order at a predetermined position. Next, it was compressed and the lower mold covered with the laminated web was covered with the upper mold with the laminated web side facing down. The mold thus filled with the short fiber aggregate was subjected to heat treatment at 200 ° C. for 15 minutes at a differential pressure of 5 mmH 2 O in a hot air circulation type hot air oven.

Then, after slowly cooling, it was taken out from the mold to obtain a molded cushion material. The molded cushion material obtained at this time had a density of the sitting portion of 0.03.
5 g / cm ³ and the edge portion is 0.045 g / cm ³
And it was as originally designed. In addition, the molded cushion material had almost no gap with the inside of the mold, and the shrinkage during thermoforming was extremely small. In addition, it was difficult to see from the appearance that they were made in layers, and the aesthetics were good. Use this molded cushion material with an initial thickness of 5
The compression to about 0% was performed 4 times.

Here, the strength of the heat fixing point (d) of the obtained cushion material was 0.6 g / de, and the strength of the heat fixing point (e) was 0.9 g / de. Also, the heat fixation point (f)
Has a strength of 0.7 g / de, the heat fixing point (g) has a strength of 1.1 g / de, and the heat fixing point (h) has a strength of 1.
It was 5 g / de.

The obtained molded cushion material is cut out,
The compression durability of the sitting portion was measured. As a result, the 25% hardness was 20 kg, the 80,000-time compression residual strain was 6%, and the 80,000-time compression hardness retention rate was 85%.

[Example 3] The same operation as in Example 2 was carried out except that the weak heat-bonding treatment was not performed and the web was packed into the mold and the heat treatment time was changed to 20 minutes. The resulting molded cushion material caused heat shrinkage during molding, but there was no problem in practical use, and the molded cushion material had a density of 0.036 g / cm ³ , 25% hardness of 2
1 kg, 80,000 times compression residual strain 6%, 80,000 times compression hardness retention rate 85%, compression residual strain 23%, which were not much different from Example 2. The strength of the heat fixing point (d) of the obtained cushion material is 0.5 g / de, and the heat fixing point (e) is
Had a strength of 0.9 g / de. The strength of the heat fixing point (f) is 0.6 g / de, and the heat fixing point (g) is
Had a strength of 1.0 g / de, and the heat fixing point (h) had a strength of 1.5 g / de. Even when the molded cushion material was cut, there were few internal gaps and the joints of the sheets were so uniform that it was difficult to distinguish them.

[Comparative Example 2] In Example 1, the mixing ratio of the short fibers (B) was 3 without mixing the short fibers (C).
It was 5 parts by weight, and was directly packed in a punching plate mold without performing the initial heat treatment at 140 ° C., and an attempt was made at 200 ° C. However, it takes a lot of time to cut, and the cut web is difficult to handle, and it is difficult to arrange a predetermined amount at a predetermined position of the punching plate mold.
A preferable molded cushion body could not be obtained because there were gaps and places where the web was folded after molding. The strength of the heat fixing point (d) of the obtained molded cushion material was 0.7 g / de, and the strength of the heat fixing point (g) was 1.
It was 2 g / de. Further, in the compression durability test on this molded cushion material, the residual compression strain of 80,000 times is as high as 9%, and it is considered that there is an effect such that the strain is concentrated by the compression on the uneven portion and the low density portion. .

[Comparative Example 3] In Example 2, 65 parts by weight of the short fibers (A) and 35 parts by weight of the short fibers (B) were mixed and the initial heat treatment temperature was changed from 140 ° C to 180 ° C. A mat-like molded product was obtained by performing the same operation as in Example 1 except for the above. The same operation as in Example 1 was performed on this mat-shaped molded body to obtain a molded cushion material. The strength of the heat-fixing point (d) of the obtained cushion material is 0.4 g / d.
and the strength of the heat fixing point (e) was 0.7 g / de. The strength of the heat fixing point (f) is 0.5 g / de, the strength of the heat fixing point (g) is 0.9 g / de,
The strength of the heat fixing point (h) was 1.1 g / de.

The cushioning material thus obtained had a residual compression strain of 80,000 cycles which was rather poor at 8% and a residual compression strain of 28% which was rather low, and the texture when compressed had a feeling of roughness. On the other hand, in the obtained molded cushion material, the fusion bond rupture strength at the heat fixing point (d) was 0.4 g / de, and the strength at the heat fixing point (g) was 0.9 g / de. The strength of the heat fixing point (d) is lower than in the case of Example 1, and it is considered that the polymer of the low melting point component of the short fiber (B) may be thermally deteriorated.

[Embodiment 4] The mat-like molded body obtained by performing the operation of Example 2 and subjected to the initial weak fusion treatment and cut is aired from the lower part of the lower mold covered with the laminated web. While suctioning, mechanically, after laminating a predetermined amount of mat-shaped molded body in a predetermined place, cover with the upper mold covered with the laminated web, put in a hot air suction furnace, while applying a differential pressure, A strong fusion treatment was performed. The molded cushion material obtained by this operation was comparable to the molded cushion material that was manually stacked and arranged and packed. This method was highly accurate even when it was repeated, and the frequency of failure was extremely low.

[Comparative Example 4] In Example 2, an attempt was made to cut the laminated web as it was without fusion treatment and mechanically pack it into the mold, but the web could not be transported well and mold packing was difficult. Met.

[Brief description of the drawings]

FIG. 1 is a schematic view of a molded fiber cushion material.

FIG. 2 is a schematic view of a mat-like molded body that has been weakly fusion-bonded and then cut for filling in a mold.

FIG. 3 is a perspective view of an upper mold.

FIG. 4 is a perspective view of a lower mold.

FIG. 5 is a schematic diagram (cross section) of packing a cut mat-like molded body into a lower mold in a laminated model.

FIG. 6 is a scanning electron micrograph (× 350) of a typical intersection of heat fixation points.

FIG. 7 is a schematic view of a cushion material formed into a chair shape.

[Explanation of symbols]

1 Fiber cushion material. 2 A mat-shaped molded body obtained by fusion-cutting short fibers (C). 3 mold. 4 Sheet-like fiber aggregate web.

Claims (14)

[Claims] 1. Inelastic polyester crimped short fibers (A)
In the molded cushion material having the aggregate as a matrix, the aggregate of the short fibers (A) occupies 40 to 90% by weight based on the weight of the molded cushion material, and further shown in the following (1) and (2), respectively. At least two of the fusible short fibers (B) and the fusible short fibers (C) are dispersed and mixed as the fusible component, and in the molding cushion material, the following (d) to
The heat-fixing points as shown in (h) are scattered, and the fracture strength of the fusion-bonded portion at the heat-fixing points (e) is larger than the fracture strength at the heat-fixing points (d). Molded cushioning material with improved durability against deformation. (1) A short fiber (B) in which a polymer (b) having a melting point of 40 to 150 ° C. lower than the melting point of the non-elastic polyester polymer constituting the short fiber (A) is exposed at least on the surface. (2) From the melting point of the polymer that constitutes the short fibers (B), 2
Short fibers (C) in which the polymer (c) having a melting point lower by 5 to 130 ° C. is exposed at least on the surface. (D) Thermal fixing point of the short fibers (A) and the short fibers (B). (E) The heat fixing point of the short fibers (A) and the short fibers (C). (F) Thermal fixation point of the short fibers (B) and the short fibers (C). (G) Thermal fixing point between the short fibers (B). (H) Thermal fixation point between the short fibers (C). 2. The molded cushioning material according to claim 1, wherein the fusion bond rupture strength at the heat fixing point (h) is higher than the strength at the heat fixing point (g). 3. The short fibers (B) are composed of a thermoplastic elastomer as a fusion component and a non-elastic polyester polymer, and the elastomer is provided on at least a part of the short fiber surface of the short fibers (B). Is an elastic composite staple fiber,
The molded cushion material according to claim 1. 4. The short fiber (C) is composed of a low melting point polyester polymer as a fusion component and an inelastic polyester polymer, and the low melting point polyester polymer is used as the short fiber surface of the short fiber (C). The molded cushion material according to claim 1, wherein the molded cushion material is an elastic composite fiber disposed in at least a part of. 5. The molded cushion material according to any one of claims 1 to 4, wherein the low melting point polyester polymer according to claim 4 is a polyethylene terephthalate copolymer polymer. 6. The mixing ratio of the short fibers (B) in the molded cushion material is higher than the mixing ratio of the short fibers (C).
5. The molded cushion material according to any one of 5. 7. The 80,000-time compression residual strain measured in accordance with JIS K-6401 is 2 to 12%.
The molded cushion material according to any one of to 6. 8. A non-elastic polyester crimped short fiber (A)
In the method for producing a molded cushion material using the aggregate as a matrix, the non-elastic polyester crimped short fibers (A) are added in an amount of 40 to 90% by weight based on the weight of the molded cushion material, and the following (1) and (2) respectively. Shown by mixing at least three of the fusible short fibers (B) and the fusible short fibers (C),
After being made into a web, the multiple sheets are laminated to form short fibers (C)
Pre-heat treatment is performed at a temperature higher than the melting point of the polymer (c) in the inside and lower than the melting point of the polymer (b) in the short fiber (B), and the heat fixation points shown in the following (e), (f) and (h) are applied. The mat-shaped molded product obtained by forming is cut and packed in a mold, and then at a temperature not lower than the melting point of the polymer (b) in the short fibers (B) and lower than the melting point of the polymer constituting the short fibers (A). Heat treatment is performed to form the heat fixing points shown in (d) and (g) below, and the rupture strength of the fusion-bonded portion at the heat fixing points shown in (e), (f) and (h) below is increased. A method for producing a molded cushioning material having improved durability against repeated large deformation, which is characterized by being molded as described above. (1) A short fiber (B) in which at least the polymer (b) having a melting point of 40 to 150 ° C. lower than the melting point of the non-elastic polyester-based polymer constituting the short fiber (A) is exposed on the surface. (2) From the melting point of the polymer that constitutes the short fibers (B), 2
Short fibers (C) in which the polymer (c) having a melting point lower by 5 to 130 ° C. is exposed at least on the surface. (D) Thermal fixing point of the short fibers (A) and the short fibers (B). (E) The heat fixing point of the short fibers (A) and the short fibers (C). (F) Thermal fixation point of the short fibers (B) and the short fibers (C). (G) Thermal fixing point between the short fibers (B). (H) Thermal fixation point between the short fibers (C). 9. The short fiber (B) comprises a thermoplastic elastomer as a fusion component and a non-elastic polyester polymer, and the elastomer is provided on at least a part of the short fiber surface of the short fiber (B). Is an elastic composite staple fiber,
The method for manufacturing the molded cushion material according to claim 8. 10. The short fiber (C) comprises a low melting point polyester polymer as a fusion component and an inelastic polyester polymer, and the low melting point polyester polymer is used as the short fiber surface of the short fiber (C). The method for producing a molded cushion material according to claim 8 or 9, which is an elastic composite fiber disposed in at least a part of. 11. The method for producing a molded cushion material according to claim 8, wherein the low melting point polyester polymer according to claim 10 is a polyethylene terephthalate copolymer polymer. 12. The mixing ratio of the short fibers (B) in the molded cushion material is higher than the mixing ratio of the short fibers (C).
11. The method for manufacturing the molded cushion material according to any one of 1 to 11. 13. The method for producing a molded cushion material according to claim 8, wherein the preheat treatment time is 1 minute or more and 10 minutes or less. 14. The method for producing a molded cushion material according to claim 8, wherein the heat treatment time is 1 minute or more and 40 minutes or less.