JPH03140185A - Fibrous filler - Google Patents

Abstract

PURPOSE:To obtain the fibrous filler which is scarcely brought to permanent strain by constituting the fibrous filler whose filling density is a specific value so that its surface layer part has higher hardness than its inner layer part, it has an elastic recovery factor exceeding a specific value against a high compressive load, and also, its compressive residual strain at a specific temperature is below a specific value. CONSTITUTION:The fibrous filler is constituted so that it is formed by laminating a thin layer web mainly composed of short fibers and its filling density is 25-80g/1000cm<2>, its surface layer part has higher hardness than that of inner layer part, and also, it has an elastic recovery factor of >=85% against repeated compression of a high compressive load, and moreover, its compressive residual strain at 70 deg.C is <=25%. As for a short fiber, it is desirable that its size is within a range of 1-30d, and its fiber length is within a range of 20-100mm. A heat welding fiber is a fiber-like object whose melting point is relatively lower than that of a short fiber used as a base material, in which at least its surface is melted by heating and which can be stuck to the short fiber. Also, from the viewpoint of improving the dispersibility of the short fiber of the heat welding fiber, it is desirable that its size is 2-10d, its fiber length is within a range of 20-60mm, and a mixing ratio of the heat welding fiber is 10-60weight% against the whole fibrous filler.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fiber filler used in cushions for vehicle seats, furniture, and the like.

[Prior Art] Conventionally, resin foams such as polyurethane foam have been mainly used as fiber fillers, but there are problems in terms of durability, etc. The use of fibers and other materials is also being considered in response to diversifying needs such as orientation.

The present inventors investigated the use of a fiber filler obtained by blowing short fibers together with an air stream through a mold for the above-mentioned purposes, and as a result, discovered the existence of problems such as coating.

[Problems to be Solved by the Invention] Fiber fillers have a problem in that they tend to weaken when used for a long period of time.

In other words, in a fiber filler made by short fiber air blowing method that does not contain fused fibers, the constituent fibers in the filler are not fixed, so there is a problem that the shape is easily deformed before it can be resistant to settling in practical use. was there.

On the other hand, in the case of a fiber filling body in which the entire filling body is uniformly partially fused, which is made by mixing fibers with fused fibers having a low melting point, blowing air into the mixture, and then heat-treating the mixture, this is due to the homogeneous structure. Since the load during practical use is applied to the entire body and the fiber filler does not have an elastic layer locally, the compression recovery property is poor, and therefore the fatigue resistance is poor.

Incidentally, if the blending ratio of low-melting point fibers is unnecessarily increased in order to improve the resistance to sagging, there is a problem in that the texture becomes board-like and the commercial value is lost.

In addition, from conventional knowledge, there are two characteristics for settling: ``elastic recovery rate against high compressive loads'' at room temperature and ``compressive residual strain'' at 70°C, which also takes into account heat storage properties under practical conditions. This is especially important.

The object of the present invention is to solve the above-mentioned problems of the prior art. The purpose of this invention is to provide a fiber filler that is resistant to staining.

Means for Solving the Problems] The fiber filler of the present invention has the following configuration in order to achieve the above object.

That is, a fiber filling body is formed by laminating thin webs mainly composed of short fibers and has a packing density of 25 to 80 g/1000 cIIi, and the filling body has a surface layer portion that is harder than an inner layer portion, and And for repeated compression with high compressive load,
The fiber filling body is characterized by having an elastic recovery rate of 85% or more and a compressive residual strain at 70° C. of 25% or less.

Hereinafter, the fiber filler of the present invention will be explained in detail.

The short fibers used as a base material in the present invention include synthetic fibers such as polyester, polyacrylic, polyamide, and polypropylene, natural fibers such as cotton, linen, silk, and wool, or combinations of these synthetic fibers and natural fibers or different types of synthetic fibers. short fibers such as mixed fibers, any of which are applicable. Among these materials, polyester is the most preferred material because of its excellent compression properties. Further, in order to uniformly disperse and blow the fibers, it is more preferable to use fibers with low entanglement.

The above short fibers preferably have a fineness of 1 to 30 d and a fiber length of 20 to 100 mm.

If the fineness is less than 1 d, the bulk of the short fibers will be small, so when making a fiber filling with a certain volume, the density will increase and the recovery against compressive load will also decrease.
If it is larger than d, the number of fibers will decrease when making a fiber filling body with a constant density, resulting in a decrease in recovery performance against compressive loads. Furthermore, if the length is longer than 100 mm, the fibers tend to get entangled, making it difficult to obtain a uniform molded product, and the recovery performance against compressive loads also decreases.

The heat-fusible fiber is a fibrous material that has a relatively lower melting point than the short fiber used as the base material, and can be melted at least on its surface by heating and bonded to the short fiber. Such heat-fusible fibers include low melting point copolyester fibers, polyolefin fibers, polyvinyl alcohol fibers, and the like. In particular, composite fibers having at least one of the above-mentioned low melting point polymer components are preferred because they have excellent shape retention and strength properties. When the composite form is a core-sheath composite fiber, a low melting point fiber is arranged in the sheath component. Particularly preferred is one in which the core components are composited into a multi-core structure.

Such heat-fusible fibers are preferably short fibers.

This is because by using short fibers, the fiber filler can be uniformly dispersed throughout, and therefore, short fibers and thin webs can be bonded uniformly. In addition, from the viewpoint of improving the dispersibility of the short fibers of this heat-fusible fiber, the fineness is 2 to 2.
It is preferable that the 10d1 fiber length is in the range of 20 to 60 mm.

The mixing ratio of heat-fusible fibers is 10 to the entire fiber filling.
It is preferably 60% by weight. If the mixing ratio of the heat-fusible fibers is less than 10% by weight, the adhesion between the short fibers will be insufficient, making it difficult to obtain the desired hardness as a fiber filler, and the recovery against compressive loads will also be poor. descend. On the other hand, if the blending ratio of heat-fusible fibers exceeds 60% by weight, the fiber filler becomes too hard, making it difficult to obtain comfortable cushioning properties.

The hardness of the filler in the present invention is characterized in that the hardness of the surface layer is higher than that of the inner layer, and the hardness of the surface layer is 35 to 95 and the hardness of the inner layer is 3 to 85. The difference in hardness between the surface layer and the inner layer of the filler is preferably within the range of 5 to 90%, particularly preferably 8.
A rough guideline is ~80%.

It may be effective even with less than this, so there is no need to be particular about the amount, but from the point of view of stability and reproducibility, 5%
If the hardness difference is below, the mold retention and settling properties of the filler will be poor, and unexpected troubles will occur during practical use, and local peeling may occur.

Note that the hardness of the entire filling body is preferably in the range of 3 to 95. If the hardness is less than 3, it is too soft for practical use. On the other hand, if it is 95 or more, it becomes too hard like a board and has no commercial value.

Moreover, it is preferable that the thickness range of the surface layer portion occupies 2 to 45% of the total thickness of the fiber filler.

That is, if it is less than 2%, the shape retention of the filler is poor and there is a problem, while if it is more than 45%, the effect of improving the settling resistance due to the structure of different hardness between the surface layer and the inner layer cannot be obtained.

In addition, in the present invention, hardness refers to a polymer meter (immediately manufactured 11
ARDNESs TESTER'TYPE C'' (De
grecs for Ce1Iular product
ts), the hardness was measured at about 25 locations, and the average value was calculated, and the hardness was taken as the hardness of that location. Note that the hardness difference refers to a value calculated by the following method using the above-mentioned measured hardness.

Hardness difference (%) = ((SI)/S) However, in order to have a sufficient elastic recovery rate and not become too hard, the filling density of the short fibers serving as the base material and the heat-fusible fibers used as necessary in the fiber filling body must be 25 ~80 g/1000 cId.

That is, if it is smaller than 25 g/10007, it will easily become stale after a short period of use, and the compressive elasticity recovery properties will be poor, resulting in poor sitting comfort. On the other hand, 80g/1000cTI
If it exceeds I, it will have a board-like texture and feel uncomfortable to sit on, which is not desirable.

Furthermore, the fiber filler of the present invention has an average compression recovery rate of 85% or more under repeated compression under high compression loads. If it is less than 85%, the elastic recovery rate is low against repeated compressive loads (therefore, it is easy to wear out even after short-term use. If it exceeds 95%, the elastic recovery rate is low, but the elastic recovery rate is low even after short-term use. This is not desirable because it is too strong and makes sitting uncomfortable during practical use.

Note that the elastic recovery rate with respect to repeated compression under a high compression load refers to a value calculated by the following method.

A load of 85 g/c& is repeatedly applied to the fiber filler 1000 times, the change in thickness is measured, and the value is calculated by the following method.

Repeated average compression recovery rate (%) (q/p) represents the average value of the measured values at four locations.

Furthermore, the fiber filler of the present invention has a compressive residual strain of 25% or less at 70°C. Compressive residual strain is 25%
If it exceeds this value, the seat will easily become stale after a short period of use, resulting in a feeling of bottoming out, making it uncomfortable to sit on. Note that it is generally difficult to reduce the compressive residual strain to 2% or less.

Note that the compression residual strain refers to a value calculated by the following method.

A test piece with a square shape of 50 mm on one side and a thickness of 40 mm was heated for 22 hours continuously in a constant temperature bath at a temperature of 70 ± 1°C.
After fixing with 0% compression and taking out, the thickness is measured after being left for 30 minutes.

Compressive residual strain (%) −((to −t+ )/lo)X
100 Here, to=thickness of the initial test piece (mm) tl - thickness of the test piece after the test (mm) In the present invention, the above-mentioned short fibers and heat-fusible fibers are usually first processed in a defibrating machine. Alternatively, spread the fibers using a card machine, etc. This is to loosen the clumps of short fibers and make full use of the crimp of the short fibers. Through this step, the fiber filler obtained later exhibits the bulk due to the short fibers, and exhibits excellent cushioning properties with sufficient repulsion against compression.

In this way, the sufficiently opened short fibers are loaded into an air-permeable side fabric or formwork having an arbitrary shape by the air flow from the cotton feeding fan.

The formwork needs to have a predetermined shape and adequate ventilation. Measured value by Frazier type air permeability tester is 5-2
It is preferable to have an air permeability in the range of 00 cc, 'crd·sec. Such a formwork can be made using, for example, a punched metal plate. in this case,
A method of filling the fibers by blowing them into an air-permeable mold having a volume at least twice the volume of the final fiber filler is preferred.

The fiber filling thus formed by being loaded into the formwork is
Thin webs made of short fibers are laminated, and this is heat-treated on a hot bed where heat-fusible fibers exhibit adhesive properties to partially bond the short fibers (and thin webs) together.

The fiber filling material produced by this method is characterized by a structure in which thin webs made of randomly arranged short fibers are arranged in a direction almost perpendicular to the flat plane. Compared to a dense fiber filler, the compressibility in the thickness direction is small and the repulsion force against compression is large, thereby providing good cushioning properties with appropriate hardness.

The feature of the present invention is that instead of the conventional uniform structure, the surface layer is a hard layer to provide °C strength, and the inner layer has a low density (low-density) triple structure to provide elasticity. The method of forming this triple structure is not particularly limited.

For example, the first method includes a method in which short fibers containing heat-fusible fibers are blown into an air-permeable mold together with an air stream to fill the mold, and then the surface layer is heat-treated more intensely than the inside.

Specific methods for strongly locally heat-treating the surface layer include, for example, applying high-temperature hot air to only the surface layer, applying infrared heating, or placing the fiber filler in a box or chamber set at a high temperature for a short period of time. I can list ways to enter it. Other means include flame,
High-temperature gas fluid, high-temperature rolls, hot plate contact/pressure bonding, etc. are used.

In addition, when contacting the hot plate and crimping, for example, a pattern may be embossed,
It is also effective to imprint a fine pattern on the fused portion of the surface using a steel plate at the same time as pressing.

A second method is to blow and fill the air-permeable mold so that more heat-fusible fibers are present in the surface layer than in the interior, and then heat-treated to partially bond the short fibers. Can be done.

Furthermore, as a third method, short fibers containing heat-fusible fibers are blown and filled into an air-permeable mold together with an air flow, and a release agent is further injected into the inside of the filling. Next, heat treatment may be used to partially bond the short fibers.

As described above, the present invention is capable of controlling the degree of partial adhesion of short fibers in the inner layer by injecting a template agent into the inside of the filler.

Furthermore, as a fourth method, short fibers containing or not containing heat-fusible fibers are blown into an air-permeable mold together with an air flow to fill the mold (7). An example of this method is to attach an adhesive resin to the surface.

That is, the present invention can employ each of the above-mentioned means as appropriate. Of course, each of the above means may be used in combination, or they may be combined.

The mold release agent used in the third method is at least one type of mold release agent selected from silicone compounds, fluorine compounds, and polyester-based mold release agents, that is, a water-repellent release agent. It is a molding agent, and can be used in either solid or liquid form, but liquid form is preferable from the point of view of uniformity.
Particularly preferred are those that are liquid and have good compatibility with the filler. However, they do not necessarily need to be compatible, and the problem of 1-minute disproportionation can be avoided by stirring just before use.

First, silicone-based compounds include methylpolydilogisane, methylborisyl[Jxane, hydrogenpolysiloxane, methylhydrogensiloxane with various degrees of polymerization, or those having phenyl groups or alkoxyl groups in the side chains, or combinations thereof. Examples include condensates and the like that are generally referred to as organopolysiloxanes.

Particularly preferred are modified silicones such as epoxy-modified silicone in which an aminoalkyl group is introduced into dimethyl silicone or alkylene oxide-modified silicone in which an alkylene oxide group is introduced. Examples of catalysts to be used in combination as necessary include tetrabutyl titanate, tetrapropyl titanate, dibutyltin diacetate, dibutyltin laurate, dibutyltin maleate, tin octylate, zinc stearate, zirconium oftate, and zirconium stearate. Examples include organometallic compounds such as. Such catalysts are used in an amount of 0.3 to 10% by weight based on the silicone agent.

Among these, preferred are those that are curable.

Some of these materials are cured by a curing agent, while others are self-cured at room temperature or by heating.

Among these, organopolysiloxanes having terminal amino groups are particularly preferred.

Of course, it is true that the effects and durability differ depending on the type of organopolysiloxane, but it is particularly preferable to further improve durability by using a triazine-based or melamine-based polymer in combination.

Next, examples of fluorine-based materials include those containing the following compounds as main components. That is, polytetrafluoroethylene (
PTFE), polychlorotrifluoroethylene (PC
TFE), polyvinylidene fluoride (PVdF),
Polyvinyl fluoride (PVF), fluorinated terpolymers, more specifically, tetrafluoroethylene-hexafluoropropene copolymer (FTFE), tetrafluoroethylene rubber fluoroalkyl vinyl ether copolymer (PFA), chlorotrifluoroethylene-ethylene copolymer (ETFE), polyvinifluoride (
PVF), etc.

More preferred is a fluorine-containing polymer having a perfluoroalkyl group in its side chain. For example, the following monomer polymers are common.

Finally, as a polyethylene wax system, the molecular weight is 15
00 to 8000 and exhibiting a wax-like appearance. If the molecular weight is less than 1,500, the softening point will be too low and the smoothness will be poor, significantly inhibiting the imparting effect;
If it is 0 or more, the resin becomes hard. Particularly preferred mold release agents in the present invention are silicone-based and fluorine-based. A small amount is highly effective, and there is little variation in adhesion and effectiveness.

The solution or emulsion of the mold release agent may be added to the filling by diluting it with the same solvent as the solution to dissolve or disperse it, or by directly adding it. It is also possible to improve the dispersion state by using a small amount of another solvent or non-solvent that is different from the addition solution. Other promising methods for improving the dispersion state include applying strong shearing force using a so-called ball mill or colloid mill, or applying ultrasonic waves.

Next, as a method for applying the mold release agent to the inside of the filling, conventional equipment and techniques such as dipping, coating, and spraying methods can be appropriately selected. After performing these treatments, it is dried and finished.

Next, the adhesion rate of the mold release agent to the filler varies greatly depending on the type of the release agent applied, the form of the filler, the structure, etc., but regardless of these factors, the rate of adhesion of the mold release agent to the filler is 0.0% relative to the solid content of the filler. 10-25
A tentative guideline is a range of 0.15 to 20% by weight, particularly preferably 0.15 to 20% by weight.

There are cases where it is effective even with less than this, so there is no need to be particular about the amount, but from the standpoint of stability and reproducibility, it is less than 0.
It is better to add 1.0% or more.

Furthermore, if 25% or more is applied, operations during application or drying become difficult, and unexpected troubles may occur. In addition, the texture may become slimy, causing inconvenience and local peeling.

Next, the following adhesive resins are used in the fourth method.

Namely, polyurethane, natural rubber, SBR.

Any polymeric substance capable of binding the constituent fibers of the fiber filler, such as NBR, polyolefin, chloropyrene, ethylene-vinyl acetate copolymer, vinyl chloride polymer, or amino acid resin, can be used as appropriate. Note that compositions containing these as main components can be used alone or in combination of two or more. The adhesive resin may be applied in any form such as a solution or an emulsion, or a combination of these may be used. Note that as a method for applying the adhesive resin to the filler, ordinary equipment and techniques such as dipping, coating, and spraying can be appropriately selected.

Next, the effects of the present invention will be explained using examples.

Example Polyester staple fiber (6d x 38mm) and heat-fusible fiber with core-sheath structure (4d x 51mm, core component: polyester, sheath component: melting point J, modified polyester at 10°C)
were mixed at a weight ratio of 60:40 and opened.

Thereafter, the fibers were filled with an air stream from a rectangular blowing port (10 cm x 5 cm) installed parallel to the relatively flat surface of a sheet-shaped mold made of a punching plate. The packing density was 40 g/l 000 cal (after compression).

Next, the surface of the filler is locally heat-treated at 180°C for 15 minutes to melt the sheath component of the heat-fusible fibers and bond the short fibers and thin web to reduce the thickness to 1.
A 40 mm sheet fiber filler (A) was obtained. The average hardness of the surface layer of this product was 55, and the average hardness of the inner layer was 33.

On the other hand, as a comparative example, a sheet-shaped formwork with a filling density of 40 g/1000 c++! and treated in a steam safeter under reduced pressure at 130°C for 15 minutes.
The entire fiber filler was uniformly heat-treated to obtain a sheet fiber filler (B) having a thickness of 140 mm.

The average hardness of the surface layer of this product was 44, and the average hardness of the inner layer was 42. Table 1 shows the results of evaluating the above two types of fiber fillers. The durability was compared by covering A and H above with the same side material, making a cushion, and sitting on it for 8 hours/day for 6 months.

In addition, in terms of durability in Table 1, ○: Almost no settling, ×: Severe settling.

Table 1 can do.

Claims (2)

[Claims] (1) A fibrous filler with a packing density of 25 to 80 g/1000cm^3, which is formed by laminating thin webs mainly composed of short fibers, and the filler has a surface layer that is harder than an inner layer. It also has an elastic recovery rate of 85% or more against high compressive loads, and has a compressive residual strain of 25% at 70°C.
% or less. (2) The fiber filler according to claim 1, wherein both the surface layer portion and the inner layer portion contain heat-fused fibers, and the surface layer portion is fused more than the inner layer portion.