JP2001055655A - Mold for forming fiber assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming mold that can be smoothly filled with the fiber assembly without obstruction and can produce cushioning materials of high quality in a low cost, when the cushioning material is produced through the air-blowing method. SOLUTION: The binder fibers that melt at a lower temperature than the melting point of the matrix staple fibers are admixed and dispersed in the matrix fibers that are made of crimped synthetic staple fibers, the fiber mixture is opened and the resultant fiber assembly F is allowed to accompany the conveying air flow and charged into the mold cavity C that is formed by surrounding the periphery with a group of wall surfaces of the air-permeable mold blocks 1-3 and the charged fiber assembly F is compressed and heat-formed. In this mold cavity C, the corners 4 of the mold that protrudes into the inside of the cavity C and/or a number of air-permeating holes bored on the wall faces of the mold blocks 1-3 for imparting the air permeation properties to the mold are all beveled at the all periphery of every opening edge so that a part of the fibers constituting the fiber assembly may not be caught by the opened edged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fiber assembly in which a binder fiber having a melting point lower than that of a short fiber is dispersed and mixed in a matrix composed of short fibers of synthetic short fibers having a crimped form. The present invention relates to a molding die for blowing and filling the fiber aggregate into a cavity of the die by pneumatic transportation in order to obtain a cushion material by heat molding.

[0002]

2. Description of the Related Art In general, urethane foam has been widely used as a material for a cushion material for a seat having a complicated shape such as an automobile or an aircraft. However, urethane foam is humid due to poor ventilation,
Since there is a problem such as difficulty in recycling, there has been a long-awaited demand for an alternative molding material.

[0003] In response to such demands, in recent years, as a material for replacing urethane foam, a fiber assembly in which binder fibers having a lower melting point than the short fibers are dispersed and mixed in a matrix composed of synthetic short fibers is used as a mold. A fiber structure (cushion material) thermoformed therein has been attracting attention as a material capable of solving the above problems. In addition,
In the following description of the present invention, "fiber aggregate" may be simply abbreviated as "cotton". In addition, it is further added that the cushioning material of the present invention is formed by thermoforming the fiber aggregate filled in the mold while shaping the mold shape.
It is formed by melting and / or softening the binder fibers contained in the fiber assembly to thermally fuse the fibers constituting the fiber assembly.

In order to manufacture such a cushion material, it is necessary to first fill the fiber assembly into the mold cavity in some form in order to shape the mold into the fiber assembly. Conventionally, the filling of such a fiber assembly has been performed by hand lay-up. However,
In order to save the labor required for filling and to shorten the filling time, a method of transporting the fiber assembly as a small lump of opened cotton together with the air flow into the cavity of the molding die (hereinafter, this method is simply referred to as " This is referred to as “air blowing method”), for example, in JP-A-62-152407, Japanese Patent Publication No. 27727/1995.
It is being carried out as proposed in Japanese Patent Publication No.

[0005] At that time, in the air blowing method, a gas permeable mold generally made of a gas permeable material having a vent such as a punching plate is used as a molding die. This is because it is necessary to quickly discharge the carrier airflow from the mold cavity through the air-permeable mold after the small lump of cotton is transported into the mold cavity along with the carrier airflow and filled. It is. Moreover, by using such a breathable mold, when the cotton filled in the mold cavity is converted into a cushion material by a heat treatment process, a heated airflow or cooling into the cotton through the breathable mold is performed. This is because the air flow can be passed through, and the heating and cooling of the cotton can be made uniform.

By the way, in the method of thermoforming a cushion material from a fiber aggregate by an air blowing method, the "fiber aggregate" itself accompanying the flow of the conveying air itself is an "aggregate of spread fine fibers". Great care must be taken in that there is. In other words, "air blowing method"
With the combination of "opened fine fiber aggregates", trivial matters, which hardly became a problem with ordinary molding techniques, become a major problem. For example, if there is a sharp edge or a slight defect on the inner wall surface of the mold for filling the fiber assembly, there is a fate that the opened thin fibers constituting the fiber assembly are easily caught by the edge and the defect. That you have. Because even if it is a part of the fiber that constitutes the cotton lump, if it is caught by such an edge or a trivial flaw, the cotton lump of the caught fiber becomes the core, and this core This is because, for the small cotton lump, another cotton small lump accumulates one after another and grows into a large cotton lump.

[0007] Such a phenomenon is peculiar to the technique of blowing and filling small lumps of cotton consisting of aggregates of opened fibers into a mold by an air blowing method.
Conventionally, such a problem has been neglected. However, the present inventors, when such a problem occurs, adversely affects the uniform filling of the cotton in the mold, uneven cotton filling, or poor reproducibility of normal mold filling. I determined that it would be. That is, the present inventors have found that, in the prior art having the above-described problems, when mass-producing the cushioning material, the quality tends to vary, and the quality of the obtained cushioning material cannot be guaranteed. In addition, the inventor has found that the number of defective products frequently occurs, and that the production yield is reduced.

[0008]

In view of the above-mentioned problems of the prior art, the problems to be solved by the present invention are:
`` Providing a molding die capable of smoothly filling a fiber aggregate so as not to be caught by a fiber while adopting a method of filling an opened fiber aggregate by a pneumatic transport flow into a mold cavity. , And "The uneven filling of the fiber aggregate into the air-permeable mold having openings can be avoided, and when mass-producing the cushioning material, the variation in quality is reduced, and the production yield of good products is reduced. It is an object of the present invention to provide a molding die capable of producing a cushioning material that can be manufactured at a low cost and excellent in quality.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a matrix fiber composed of a synthetic short fiber having a crimped form and a binder fiber having a lower melting point than the short fiber. The dispersed and mixed opened fiber aggregates are caused to accompany the carrier air flow, and filled into a mold cavity formed by being surrounded by a mold wall group, and the filled fiber aggregates are compressed and heated. For molding,
In a molding die having air permeability, at the time of filling the fiber cavity into the mold cavity, a corner of the molding die protruding into the inside of the mold cavity, and / or a material for providing air permeability. In order to prevent a part of the fiber constituting the fiber assembly from being caught on the entire periphery of each opening edge of the large number of ventilation holes formed in the wall surface of the molding die, the R-shape and / or
Or, a molding die of a fiber assembly characterized by being chamfered is provided.

In this case, the "mold for forming a fiber assembly" of the present invention is defined as "the mold for forming the mold cavity comprises an upper mold, a lower mold, and a side mold, The upper mold and / or the lower mold are composed of divided mold members, and each of the divided mold members is movable in the compression direction of the fiber assembly filled in the mold cavity. Being a `` mold '', the fiber assembly can be smoothly filled into the mold cavity, and the packing density of the fiber assembly thus filled can be partially and selectively adjusted. Is preferred in that the properties of the cushion material thermoformed by the method can be optimized.

In the "mold for forming a fiber assembly" of the present invention, "the mold is a mold manufactured by electroforming" or "the mold for forming the mold cavity" The inner wall group is made of polytetrafluoroethylene, polytrifluoride
It is a molding die coated with any one fluororesin selected from the group consisting of ethylene chloride and polyfluorinated ethylene / propylene ", in order to smoothly fill the fiber assembly into the mold cavity. Is more preferable.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Here, in describing the details of the molding die of the present invention, a fiber assembly to be filled in the molding die of the present invention will be briefly described below.
First, as the short fibers of the synthetic fibers constituting the matrix of the fiber aggregate of the present invention, it is not particularly limited,
For example, ordinary polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polytetramethylene terephthalate, poly 1,4-
Dimethylcyclohexane terephthalate, polypivalolactone, or a short fiber composed of a copolymer thereof,
A mixed fiber of these fibers or a composite fiber composed of two or more of the above-mentioned polymer components is preferable. Further, the cross-sectional shape of the short fiber may be any of a circle, a flat shape, an irregular shape, and a hollow shape. Furthermore, the crimp in this case is
It is preferable to be an apparent crimp, and the apparent crimp can be obtained by a mechanical method using a crimper or the like, a method by anisotropic cooling during spinning, a method by heating a side-by-side type or an eccentric sea core type composite fiber, or the like. it can.

On the other hand, examples of the binder fiber include a fiber made of a polymer of a polyurethane elastomer or a polyester elastomer. Among these fibers, it is particularly preferable to use a composite fiber comprising the elastomer component and the component constituting the matrix fiber. At this time, it is preferable to use a conjugate fiber in which the elastomer is exposed on a part of the surface of the conjugate fiber. The binder fibers of the present invention may be appropriately dispersed and mixed in the matrix fibers according to the required characteristics of the cushion material to be molded.

Regarding the “mold for forming a fiber assembly” of the present invention for filling the above-described fiber assembly into a mold cavity and thermoforming into a cushion material, an embodiment of the invention will be described with reference to the drawings. This will be described in detail below with reference to FIG. FIG. 1 is a side sectional view schematically illustrating a molding die of a fiber assembly for carrying out the method of the present invention. In the figure,
C is a mold cavity, F is a fiber assembly (cotton), 1 is an upper mold (hereinafter sometimes simply referred to as “upper mold”), 2 is a lower mold (hereinafter simply referred to as “lower mold”). Sometimes),
Reference numeral 3 denotes a side mold (hereinafter, sometimes simply referred to as a "side mold", and the "side mold" is also referred to as a "mold outer frame").
And 4 'indicate the corners of the upper mold, and 5 indicates the blow port. The upper die 1 has a plurality (see FIG. 1).
The upper mold member 10 is divided into three parts.
1, 102, and 103. Further, in the embodiment of FIG. 1, an example in which the lower mold 2 is not divided is illustrated. However, it is needless to say that the lower mold 2 can be divided into a plurality of pieces like the upper mold. At this time, the mold cavity C is formed by being surrounded by a mold wall group including an upper mold 1, a lower mold 2, and a side mold 3. Further, the upper mold 1 (the upper mold members 101, 102, and 10)
3) and / or the lower mold 2 is movable in the compression direction (vertical direction) of the fiber assembly F filled in the mold cavity C.

As described above, since the upper mold 1 and / or the lower mold 2 is configured, the fiber assembly in which the upper mold 1 and / or the lower mold 2 is filled in the mold cavity C is provided. By moving in the compression direction of the body F, the filled fiber aggregate F can be compressed to a predetermined packing density. In addition, since the upper mold 1 and / or the lower mold 2 are divided into a plurality of pieces, for example, in the embodiment of FIG. 1, the upper mold members 101, 102, and 103 are respectively moved in the compression direction of the fiber assembly F. Can be moved individually and independently.
Therefore, the upper mold members 101, 10
2 and 103, the respective movement stroke lengths (each movement distance) can be individually and independently adjusted. For this reason, the filling density of the fiber assembly F in the molds 1 to 3 is locally changed according to the degree of compression of the fiber assembly F determined according to each movement stroke length (each movement distance). And can be selectively changed. As a result, for the cushion material thermoformed in the molds 1 to 3, properties such as hardness and softness, which represent a part of the cushion performance, are applied to desired portions of the cushion material to be molded. Thus, they can be set partially and selectively.

In the molding die of the present invention configured as described above, a small lump of cotton F, which has been spread to a desired state by a fiber opening device (not shown), maintains the spread state. The mold is conveyed by the carrier airflow, and is blown and filled into the mold cavity C from the blowing port 5 provided in the side mold 3. At this time, if there are corners (sharp edges) 4 and 4 'or slight defects in the inner wall group of the upper mold 1, the lower mold 2, and the side mold 3 for filling the cotton F, the cotton F itself It is known that some of the fibers constituting the cotton F have a fate of being easily caught by these corners 4 and 4 'and defects because of the "opened thin fibers". As already described in the section of technology.

Therefore, in order to solve such a problem, in the molding die of the present invention, "when filling the fiber assembly into the mold cavity, the corner of the molding die protruding into the mold cavity is formed. A part of the fiber constituting the fiber assembly is formed on the entire periphery of each opening edge of a plurality of ventilation holes formed in the wall of the molding die in order to provide air permeability. The R feature and / or chamfering so as not to be caught "is one of the major features. In this regard, with reference to FIG. 2 (which is an enlarged perspective view of the small circled portion of FIG. 1, ie, the corners 4 and 4 '), one of the major features of the present invention will be described below in the prior art. This will be described in detail in comparison with the above. In FIG. 2, reference numeral 6 denotes an R-chamfered portion, 7 denotes a chamfered portion, and 8 denotes a group of ventilation holes formed in each wall surface of each of the molds 1 to 3. Also, 102a-
Reference numeral 102c denotes a mold wall group of the upper mold member 102. In this case, in the embodiment illustrated in FIG. 2, the mold wall surfaces 102b and 102c have been described in which the vent holes are not perforated, but the vent holes may be perforated in this portion. .

Generally, when the fiber assembly F filled in the mold cavity C is compressed and thermoformed into a cushion material, adjacent portions (connections) of the divided upper mold member groups 101 to 103 are connected. In order to prevent the shape of the portion from being transferred to the cushion material, the adjacent portions of the upper mold members need to be connected to each other with a smooth curved surface so as not to cause irregularities or steps (indicated by a two-dot chain line in FIG. 1). See section shown). However, when filling the fiber assembly (cotton) F into the mold cavity C, for example, the filling density of the fiber assembly F filled in the mold cavity C is adjusted as shown in FIG. 1 (see FIG. 1). In the embodiment, an example is shown in which the filling density at the central portion is reduced and the filling density at both ends is adjusted to increase).
When the moving stroke length of No. 2 is shortened, the following problem occurs.

That is, in the above case, FIG.
As shown in (1), it is essential that the upper mold member 102 protrudes into the mold cavity C with respect to the other upper mold members 101 and 103. Therefore, at this time, a state in which the corners 4 and 4 ′ of the upper mold member 102 protrude into the mold cavity C appears. If the corners 4 and 4 'protrude into the mold cavity C, fibers constituting a part of the cotton F conveyed together with the conveying air flow are caught on the corners 4 and 4'. This causes serious problems as described in the section of the prior art.

That is, in the prior art, the upper mold member 1
Although the corners 4 and 4 ′ of No. 02 protrude into the mold cavity C, sharp edges are formed at the corners 4 and 4 ′ as shown in FIG. A small lump of cotton F had been caught on the ground. On the contrary,
In the molding die of the present invention, cotton F is formed on the corners 4 and 4 'of the upper die member 102 protruding into the mold cavity C as shown in FIGS. As shown in FIG.
It is chamfered (see the portion indicated by reference numeral 6 in FIG. 2A) and / or chamfered (see the portion indicated by reference numeral 7 in FIG. 2B).

Further, in the molding die of the present invention, in particular, in the molding die having a large number of ventilation holes 8 perforated on the wall surface of the molding die in order to impart air permeability, the above-mentioned R-shaping and R-shaping are also required. It is important to perform chamfering. This will be described in detail with reference to FIG. 3 (which shows a cross-sectional view of the air hole 8 formed in the mold wall).

Generally, as shown in FIG.
3 are perforated with a large number of air holes 8 in order to impart air permeability. When the opening edges of the air holes have a sharp angle as shown in FIG. Cotton F in this part 11
And the molded product is liable to generate defects and fuzz. Therefore, in the molding die of the present invention, FIG.
As illustrated in FIG. 3B, a rounding 9 is formed on the entire circumference of the ventilation hole group 8 on the cavity side of each opening edge, and / or a chamfering 10 is performed as illustrated in FIG. 3C. This solves this problem.

In this case, the rounding and / or chamfering processing on the entire periphery of each opening edge of the ventilation hole group 8 is performed not only on the opening edge on the cavity side but also on FIG.
As illustrated in (c), it is more preferable to perform it on both sides of the opening edge on the cavity side and the opening edge on the opposite side to the cavity. This is because, by rounding 9 and / or chamfering 10 the opening edges of the cavity side and the opposite side of the cavity, when the cotton F is clogged in the ventilation hole 8, it becomes easy to remove the clogged cotton F. .

In this case, the rounding 9 and / or chamfering 10 can be performed by physical processing such as cutting or polishing, but chemical processing can also be used.
For example, as a method used for the chemical treatment, a process in which a mold having the holes 8 formed therein is immersed in a sulfuric acid solution for a certain period of time to smooth the mold surface and the corners of the group of openings of the holes 8. And the like.

Further, in the molding die of the present invention, the inside wall group of the dies 1 to 3 constituting the mold cavity C has defects or sharpness such that even a part of the fiber constituting the cotton F is caught. Polished finish (buffed finish) so that there is no unevenness
It is preferable to finish the inner wall surface of the mold smoothly by performing such finishing treatment.

The smooth finishing method in this case is not limited to a physical finishing method such as the above-mentioned polishing finish (buff finish). For example, polytetrafluoroethylene, polytrifluoride-chloride is used. The surface may be coated with a fluororesin such as ethylene and polyfluoroethylene / propylene, a ceramic such as alumina oxide and titanium oxide, or a metal such as chromium and nickel to finish it smoothly. Needless to say, the surface may be smoothed by a plating process such as chrome plating or nickel plating.

In this case, the molding die is, of course, required to have heat resistance in order to heat-mold the fiber assembly F. It is more preferable that the surface is covered with a substance having a low coefficient of friction so that the material can slide smoothly. Furthermore, since the thermoformed cushion material easily adheres to the dies 1 to 3, it is preferable to improve the releasability of the formed cushion material from the dies 1 to 3.

From such a viewpoint, the above-mentioned fluororesin such as polytetrafluoroethylene, polytrifluoride-ethylene chloride, and polyfluoroethylene / propylene is coated on the inner wall surfaces of the molds 1 to 3. Is more preferred. At this time, the surface condition of the inner wall surface group of the molds 1 to 3 may be a mirror surface or may have an appropriate surface roughness. The important thing is that
The purpose is to prevent the fiber assembly F from being caught on the inner wall groups 1 to 3 of the mold.

Next, as a molding die of the present invention, an "electroforming mold" manufactured by "electroforming" schematically illustrated in FIG.
It is preferable that Here, the “electroforming mold” means that the insulating material 12 is formed into the matrix 1 according to the hole shape required for the molding die.
3 and 13 'are applied to the release coatings 15 and 15', and the dies 13 and 13 'are immersed in the electroforming bath 16, and are required on the dies 13 and 13' via the release coatings 15 and 15 '. After forming an electroplating layer having a large thickness, the plating layer is
The molds 14 and 14 ′, called masters, having a cross section as illustrated in FIG.
Is a way to get

The advantages of using the "electroforming mold" as the molding die of the present invention are as follows. That is,
First, the "electroforming mold" has a high processing accuracy and can correctly copy the surface of the base material. For this reason, the distribution and diameter of the holes of the group of air holes to be drilled in the dies 1 to 3 can be processed in a large amount exactly according to the original pattern. Furthermore, if necessary, the surface roughness and the mirror surface state of the inner wall surfaces of the dies 1 to 3 can be controlled by changing the surface state of the matrix.

Second, even if the shapes of the molds 1 to 3 are large and complicated, the molds 1 to 3 having a large and complicated shape can be manufactured as a single unit without a seam. Can be In addition, in this electroforming, it is extremely easy to perform rounding and / or chamfering on the corners of the molds 1 to 3 and the ventilation holes. Therefore, there is a problem that a plurality of complicated processes such as drilling of the ventilation hole group 8 or rounding and / or chamfering of the drilled ventilation hole group are required after forming the molds 1 to 3 again. It can also be avoided.

In other words, in a conventional molding die that does not rely on electroforming, it is extremely complicated to form an extremely large number of air holes 8 in the molds 1 to 3 according to the hole diameter and distribution density pattern of the air holes. It is an extremely complicated task, and it is also an extremely complicated task to perform rounding and / or chamfering on the opening edges of these ventilation holes 8. Furthermore, in order to manufacture a molding die having a complicated and smooth curved surface, it is necessary to perform a molding process that does not have a portion where a part of the opened fine fiber is caught by a plurality of processing steps. However, according to the electroforming mold of the present invention, there is also an advantage that a large-sized molding die having a complicated and smooth three-dimensional curved surface can be manufactured at a stretch without a seam.

[0033]

As described above, according to the molding die of the present invention, while the air blowing method of packing the fiber assembly into the molding die by pneumatic transportation is employed, the conventional technique is used. Can overcome the disadvantages of That is,
By adopting the molding die of the present invention, when different physical properties (packing density) are required for each part of the molded product, the die member is protruded into the mold cavity in order to realize this. In this case, even when a mold having a group of air holes is used, the cotton does not catch on the opening edge of the air hole and / or the corner of the protruding mold member.
For this reason, according to the molding die of the present invention, it is possible to finely control the filling density of the fiber aggregate, and furthermore, when a component such as a metal is incorporated into the mold cavity and molded, cotton is caught. Without this, there is an effect that the fiber assembly can be smoothly filled in the mold cavity. Therefore, in the method of filling the fiber assembly into the mold cavity by the air blowing method, the problem of the fiber assembly being caught can be overcome. For this reason, it is possible to prevent the occurrence of defective moldings, and to provide a molding die capable of suppressing molding costs, whereby a high-quality, low-cost cushioning material is thermoformed from a fiber aggregate. It has a remarkable effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view of a molding die illustrating a state of a mold cavity when a fiber assembly is filled by an air blowing method.

FIG. 2 is a partial perspective view schematically illustrating, in an enlarged manner, various forms of a corner formed by projecting a mold cavity into one of the divided upper mold members.

FIG. 3 is a cross-sectional view of a ventilation hole of a molding die.

FIG. 4 (a) is an explanatory diagram for schematically explaining a molding method of a metal mold using an electroforming mold. FIG. 3B is a diagram illustrating a state where an insulating material is applied to the matrix.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 upper mold 2 lower mold 3 side mold 4, 4 ′ projecting corner of molding die 5 blowing port of fiber assembly C mold cavity F fiber assembly

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinnori Kataoka 3-4-1 Amihara, Ibaraki-shi, Osaka Teijin Limited Osaka Research Center (72) Inventor Masanao Yamaguchi 3-4-1 Amihara, Ibaraki-shi, Osaka No. 1 Teijin Limited Osaka Research Center (72) Inventor Takayasu Mori 25-25 Ueikeike, Yoshiwara-cho, Toyota-shi, Aichi Pref. Incorporated F term (reference) 4F202 AC00 AD16 CA09 CA17 CB01 CK15 CP08 4L047 AA28 AB02 BA05 BA09 CB09 CC16 EA10

Claims (4)

[Claims] Claims: 1. An opened fiber aggregate in which binder fibers having a melting point lower than that of short fibers are dispersed and mixed in matrix fibers made of synthetic short fibers having a crimped form, accompanied by a carrier air flow, In a mold having air permeability, for filling into a mold cavity formed by being surrounded by a group of mold wall surfaces, and compressing and thermoforming the filled fiber assembly, At the time of filling of the fiber assembly, the corners of the molding die protruding into the mold cavity, and / or
Or, a part of the fibers constituting the fiber assembly is not caught on the entire periphery of each opening edge of a large number of ventilation holes perforated on the wall surface of the molding die to impart air permeability. A molding die for a fiber assembly, which is chamfered and / or chamfered. 2. The molding die according to claim 1, wherein said molding die forming said mold cavity is an upper die,
The upper mold and / or the lower mold consist of a divided mold member group including a lower mold and a side mold, and each of the divided mold members is filled in the mold cavity. A molding die for a fiber assembly, which is movable in a compression direction of the fiber assembly. 3. The molding die according to claim 1, wherein said one or more fluororesins selected from the group consisting of polytetrafluoroethylene, polytrifluoride-ethylene chloride, and polyfluoroethylene / propylene. A mold for forming a fiber assembly, wherein an inner wall surface group of a mold forming the mold cavity is coated. 4. A molding die for a fiber assembly according to claim 1, wherein said molding die is a die manufactured by electroforming.