JPH0681639B2 - Fiber filler - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fiber filler used for cushions such as vehicle seats and furniture.

[Prior Art] Conventionally, a resin foam such as polyurethane foam has been mainly used as a fiber filler, but there is a problem that it is not sufficiently satisfactory in durability etc. The use of fibers and other materials is also being considered in consideration of diversifying needs such as orientation.

The present inventors have investigated the use of a fiber filler obtained by using a method of blowing short fibers into a mold together with an air flow, and as a result, have found the following problems.

[Problems to be Solved by the Invention] The fiber-filled body has a problem that it is easily set when used for a long period of time.

That is, in the fiber filler made by the short fiber air blowing method that does not include the fused fiber, since the constituent fibers in the filler are not fixed, there is a problem that the shape easily deforms before the settling resistance in practical use. there were.

On the other hand, in the case of a fiber filling body in which fused fibers having a low melting point are mixed with fibers, and the whole filling body made by a method of heat treating after air-blowing it is uniformly fused, due to the uniform structure. The load during practical use is applied to the whole, and since the elastic layer is not locally held in the fiber filler, the compression recovery property is poor and therefore the sag resistance is poor.

In addition, there is a problem that if the mixing ratio of the low melting point fibers is unnecessarily increased in order to improve the settling resistance, a feeling like a plate is obtained and the commercial value is lost.

In addition, from the conventional knowledge, regarding the settling, two characteristics of “elastic recovery rate under high compression load” at room temperature and “compression residual strain” at 70 ° C considering the heat storage property in practical use are especially important. is important.

The object of the present invention is to eliminate the above-mentioned problems of the prior art, has a sufficient elastic recovery rate against a high compression load, and has a small compressive residual strain at 70 ° C. The purpose of the present invention is to provide a fiber filler that does not easily get loose.

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

That is, a packing density obtained by laminating thin-layered webs mainly composed of short fibers is 25 to 80 g / 1000 cm ³ , and the packing has a surface layer portion having a higher hardness than the inner layer portion. In addition, the fiber-filled body is characterized by having an elastic recovery rate of 85% or more against repeated compression under a high compression load, and further having a compression residual strain of 25% or less at 70 ° C.

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

The short fibers used as the substrate in the present invention are synthetic fibers such as polyester, polyacrylic, polyamide, polypropylene, natural fibers such as cotton, hemp, silk, and wool, or these synthetic fibers and natural fibers or different kinds of synthetic fibers. It is a short fiber such as a mixed fiber of, and any of them is applicable. Of these, polyester, which has excellent compression properties, is the most preferable material. Further, in order to uniformly disperse and blow the fibers, it is more preferable to use fibers having a low entanglement property.

The short fiber has a fineness in the range of 1 to 30d,
The fiber length is preferably in the range of 20 to 100 mm. Fineness is 1d
If it is smaller, the bulk of the short fibers becomes smaller, so that the density becomes higher when a fiber packing having a constant volume is made, and the recoverability against a compressive load also decreases. On the other hand, if it is larger than 30d, the number of fibers is reduced when a fiber packing having a constant density is produced, so that the recoverability against a compressive load is lowered. Further, if it is longer than 100 mm, the fibers are likely to be entangled with each other, so that it becomes difficult to obtain a uniform molded body, and the recoverability against a compressive load is lowered.

The heat-fusible fiber is a fibrous material having a relatively lower melting point than the short fiber used as the above-mentioned base material, and at least its surface is melted by heating and can be bonded to the short fiber. Examples of such heat-fusible fibers include low melting point copolyester fibers, polyolefin fibers, and polyvinyl alcohol fibers. In particular, the conjugate fiber having the low melting point polymer component as described above in at least one side is preferable because it has excellent shape retention and strength characteristics. When the composite form is a core-sheath composite fiber, the low melting point fiber is arranged in the sheath component. Particularly preferred is a composite of core components in a multi-core form.

Such heat fusible fibers are preferably short fibers. By using short fibers, the fiber filler can be uniformly dispersed throughout, and therefore, short fibers and thin layer webs can be evenly bonded. Further, from the viewpoint of improving the dispersibility of the short fibers of the heat-fusible fiber, the fineness is 2 to 10d,
The fiber length is preferably in the range of 20 to 60 mm.

The mixing ratio of the heat-fusible fibers is 10 to the entire fiber filler.
It is preferably 60% by weight. When the mixing ratio of the heat-fusible fibers is less than 10% by weight, the adhesiveness between the short fibers becomes insufficient, it becomes difficult to obtain a predetermined hardness as a fiber filler, and the recoverability against a compressive load is also increased. descend.
On the other hand, when the mixing ratio of the heat-fusible fibers is more than 60% by weight, the fiber filler becomes too hard and it becomes difficult to obtain a comfortable cushioning property.

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

Even if it is less than this, it may be effective, and although it is not particularly important in terms of quantity, it is 5% in terms of stability and reproducibility.
When the hardness difference is as follows, the mold-holding property and the sag property of the filling body are deteriorated, an unexpected trouble occurs during practical use, and peeling may occur locally.

The hardness of the entire filler is preferably in the range of 3 to 95.
If the hardness is 3 or less, it is too soft to be put to practical use. On the other hand, if it is 95 or more, it becomes too hard like a plate and loses its commercial value.

Further, the thickness range of the surface layer portion preferably occupies 2 to 45% with respect to the total thickness of the fiber filling body. That is, if it is less than 2%, there is a problem that the shape retention of the filler is inferior.
If it is more than 0.1%, the effect of improving the sag resistance due to the different hardness structure of the surface layer portion and the inner layer portion cannot be obtained.

In the present invention, the hardness means HA manufactured by Kobunshi Keiki Co., Ltd.
RDNESS TESTER "TYPE C" (Degrees for Cellufar
The hardness of about 25 places was measured using the products), and the average value was calculated, and the hardness was defined as the hardness of that part. The hardness difference is a value calculated by the following method using the measured hardness.

Hardness difference (%) = {(S−I) / S} × 100, where S = hardness of the surface layer portion of the filling body I = hardness of the inner layer portion of the filling body Further, in the present invention, the fiber filling body is subjected to a compression load. In addition to having a sufficient elastic recovery rate against, in order not to be too hard, the filling density of the short fiber to be the base material and the heat-fusible fiber used as necessary in the fiber filler, The range is 25 to 80 g / 1000 cm ³ .

That is, if it is less than 25 g / 1000 cm ³ , it will easily settle down after a short period of use, the compression elastic recovery characteristics will be poor, and the sitting comfort will be poor. On the other hand, if it exceeds 80 g / 1000 cm ³ , it is not preferable because it gives a plate-like feel and a comfortable sitting feeling.

Further, the fiber filler of the present invention has an average compression recovery rate of 85% or more against repeated compression under a high compression load.
If it is less than 85%, the elastic recovery rate against repeated compressive load is low, and therefore, it tends to be liable to be worn out even if it is used for a short period of time. If it exceeds 95%, the sag is reduced, but the resilience is too strong, and the sitting comfort during practical use becomes unfavorable.

The elastic recovery rate against repeated compression under a high compression load is a value calculated by the following method.

A load of 85 g / cm ² is repeatedly applied 1000 times on the fiber filler, the change in thickness is measured, and the value is calculated by the following method.

Cyclic average compression recovery rate (%) = (q / p) x 100 where q: Thickness after cyclic loading (mm) p: Thickness before cyclic loading (mm) where q and p are the fibers The average value of the measured values at four points of the filling body is shown.

Furthermore, the fiber filler of the present invention has a compression residual strain at 70 ° C. of 25% or less. If the compressive residual strain exceeds 25%, the product will easily get tired after a short period of use, and it will cause a feeling of bottoming, resulting in poor seating comfort. It is generally difficult to reduce the compression residual strain to 2% or less.

The compressive residual strain is a value calculated by the following method.

A square with a side of 50 mm and a thickness of 40 mm is used for the temperature 70 ± 1 ℃.
In a constant-temperature layer, the sample is compressed and fixed at 50% under heating for 22 hours continuously, taken out, and allowed to stand for 30 minutes, and its thickness is measured.

Compressive residual strain (%) = {(t ₀ −t ₁ ) / t ₀ } × 100 where t ₀ = thickness of initial test piece (mm) t ₁ = thickness of test piece after test (mm In the present invention, the above-mentioned short fibers and heat-fusible fibers are usually first opened through a defibrating machine or a card machine. This is to loosen the lumps of short fibers so that the crimps of the short fibers can be fully utilized. By this step, the fiber-filled body obtained later fully exhibits the bulk of the short fibers and exhibits sufficient cushioning properties with sufficient repulsion against compression.

In this way, the sufficiently opened short fibers are loaded on the breathable side material or form having any shape by the air flow of the cotton feeding fan.

The formwork has a predetermined shape and is required to have appropriate breathability. Measured value by Frazier type breathability tester is 5-20
It is preferable to have air permeability in the range of 0 cc / cm ² · sec. Such a mold can be made using, for example, a punching metal plate or the like. In this case, a method of blowing and filling in a breathable mold having a volume of at least twice the volume of the final fiber filling body is preferable.

Thus, the fiber filling formed by being loaded into the formwork is
A thin web of short fibers is laminated, and this is heat-treated on a hot bed where the heat-fusible fibers have adhesiveness to partially bond short fibers (and thin webs).

The fiber packing produced by this method is characterized in that it has a structure in which thin-layer webs composed of randomly arranged short fibers are arranged in a direction substantially perpendicular to the plane of polarization, and a web sheet is stacked by the card web method. The compressibility in the thickness direction is smaller than that of the embedded fiber filler, and the repulsive force against the compression is large, whereby good cushioning properties having appropriate hardness can be obtained.

The feature of the present invention is not a conventional uniform structure, but a triple layer structure in which the surface layer portion is a hard layer to give strength and the inner layer portion has elasticity to have a low density. This 3
The method of double structuring is not particularly limited.

For example, as a first method, there can be mentioned 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 fibers, and then the surface layer portion is heat-treated more strongly than the inside.

As a specific method of locally and strongly heat-treating the surface layer part, for example, by applying high-temperature hot air only to the surface layer part, by infrared heating, or by heating the fiber filler in a box or chamber set to a high temperature for a short time. The method of putting in can be mentioned. As other means, flame, high-temperature gas fluid, high-temperature roll, hot plate contact and pressure bonding, etc. are used.

During hot plate contact and pressure bonding, it is also effective to form a fine pattern at the same time as pressure bonding to the fusion-bonded portion of the surface using an iron plate with a pattern embossed.

The second method is to blow the heat-fusible fiber into the air-permeable mold so that the surface layer portion is present in a larger amount than the inside, and then heat-treat to partially bond the short fiber. You can

Further, as a third method, short fibers containing a heat-fusible fiber are blown into an air-permeable mold together with an air flow to be filled, and a mold release agent is injected and applied inside the filled material. Then, a method of heat-treating to partially bond the short fibers can be mentioned.

As described above, the present invention can control the degree of partial adhesion of the short fibers in the inner layer portion by injecting the mold release agent inside the filling material.

Further, 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, and before or after heat treatment, the surface layer portion of the filling is filled. A method of attaching an adhesive resin can be mentioned.

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

The release agent used in the third method is at least one release agent selected from silicone compounds, fluorine compounds and polyethylene wax release agents, that is,
It is a water-repellent release agent and may be used in a solid form or a liquid form, but a liquid form is preferable from the viewpoint of uniformity, and a liquid form and a good compatibility with the filler are particularly preferable. However, they do not necessarily have to be compatible with each other, and the problem of nonuniformity can be sufficiently avoided by stirring immediately before use.

First, as the silicone-based compound, dimethylpolysiloxane having various degrees of polymerization, methylpolysiloxane, hydrogen polysiloxane, methylhydrodiene siloxane, or a compound having a phenyl group or an alkoxyl group in a side chain, or a cocondensation product thereof. And the like, which are generally called organopolysiloxanes.

Further, a modified silicone such as an epoxy modified silicone in which an aminoalkyl group is introduced into dimethyl silicone or an alkylene oxide modified silicone in which an alkylene oxide group is introduced is particularly preferable. Examples of the catalyst used in combination as necessary include, for example, tetrabutyl titanate, tetrapropyl titanate, dibutyltin diacetate, dibutyltin laurate, dibutyltin maleate, tin octylate, zinc stearate, zirconium octate, and zirconium. Organometallic compounds such as stearates may be mentioned. Such a catalyst is used in an amount of 0.3 to 10% by weight based on the silicone agent.

Of these, the curable ones are preferable. Some of them cure with a curing agent and some self-cure at room temperature or with heating. Among these, organopolysiloxanes having terminal amino groups are particularly preferable.

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

Next, examples of the fluorine-based compound include those containing the following compounds as main components. That is, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTF
E), polyvinylidene fluoride (PVdF), polyvinyl fluoride (PVF), fluorinated terpolymer, more specifically, tetrafluoroethylene-hexafluoropropene copolymer (FTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Polymer) PFA),
Chlorotrifluoroethylene-ethylene copolymer (ETF
E), poly vinyl fluoride (PVF), etc.

More preferred is a fluoropolymer having a perfluoroalkyl group in its side chain. For example, polymers of the following monomers are common.

Lastly, the molecular weight of polyethylene wax is 1500
Those having a waxy form of up to 8,000 are preferable. When the molecular weight is 1500 or less, the softening point is too low and the smoothness is inferior and the imparting effect is significantly impaired, and when the molecular weight is 8000 or more, the resin becomes hard. Particularly preferable releasing agents in the present invention are silicone type and fluorine type. A small amount has a large effect, and there is little variation in the imparting effect.

The release agent solution or emulsion may be added to the filler by diluting it with the same solvent as the solution to be added and then dissolving or dispersing it, or by adding it directly. It is also possible to improve the dispersion state by adding a small amount of another solvent or a non-solvent different from the solution to be added at the time of addition. Other methods for improving the dispersed state are to apply a strong shearing force with a so-called ball mill, colloid mill, etc.,
Alternatively, it is effective to apply ultrasonic waves.

Next, as a method of applying such a release agent to the inside of the filling material, an ordinary apparatus and technique such as a dip coating method and a spray method can be appropriately selected. After these treatments, the product is dried and finished.

Next, the rate of adhesion of the release agent to the filler largely varies depending on the type of the applied release agent, the form of the filler, the configuration, etc., but regardless of them, 0.10 to the solid content of the filler. The range of 25% by weight, particularly preferably 0.15 to 20% by weight is used as a rough standard.

This may be effective even if it is small, and although it is not particularly important in terms of quantity, it is 0 in terms of stability and reproducibility.
It is better to give 10% or more.

Further, if it is applied in an amount of 25% or more, the operation at the time of application or during the drying treatment becomes difficult, and an unexpected trouble may occur. In addition, the feeling of sliminess becomes stronger in terms of texture, which may cause inconvenience and local peeling.

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

That is, polyurethane, natural rubber, SBR, NBR, polyolefin, chloropyrene, ethylene-vinyl acetate copolymer, vinyl chloride polymer, amino acid resin, and other polymeric substances capable of binding the constituent fibers of the fiber filling can be appropriately used. Is. The compositions containing these as main components may be used alone or in combination of two or more. The adhesive resin may be applied in any form such as solution or emulsion, or may be used in combination. As a method of applying the adhesive resin to the filling material, an ordinary apparatus and technique such as dipping, coating, and spraying method can be appropriately selected.

Next, the effects of the present invention will be described with reference to examples.

Example Polyester short fiber (6d × 38mm) and core-sheath structure heat-fusible fiber (4d × 51mm, core component: polyester, sheath component: melting point)
Modified polyester (110 ° C) is mixed in a weight ratio of 60:40,
The fiber was opened. Then, the above fibers were filled by an air flow from a rectangular blow port (10 cm × 5 cm) attached in parallel with a relatively flat surface of a sheet-shaped mold made of a punching plate. The packing density was 40 g / 1000 cm ³ (after compression).

Next, the surface of the filler is heat-treated locally at 180 ° C for 15 minutes to melt the sheath component of the heat-fusible fiber, and the short fiber and the thin-layer web are adhered to each other to have a thickness of 140 mm. A fiber filler for a sheet (A) was obtained. The average hardness of the surface layer portion of this product was 55, and the average hardness of the inner layer portion was 33.

On the other hand, as a comparative example, in the same manner as above, a sheet-shaped mold having a packing density of 40 g / 1000 cm ³ was prepared, and treated in a steam setter under reduced pressure at 130 ° C. for 15 minutes to uniformly heat-treat the entire fiber filler. And a fiber filler for sheets with a thickness of 140 mm (B)
Got The average hardness of the surface layer portion of this product was 44, and the average hardness of the inner layer portion was 42. Table 1 shows the results of evaluating the above two types of fiber fillers. The durability was compared by covering the above A and B with the same side fabric, forming a cushion, and sitting for 8 hours / day for 6 months.

In addition, in the durability in Table 1, ◯: Almost no set, and ×: Large set.

From Table 1, the compressive residual strain of the fiber filler of the present invention was 21%, which was as small as about half that of the comparative example. Moreover, it is clear that the durability is excellent in a practical test.

[Effects of the Invention] According to the present invention, compared to the conventional uniform structure, the surface layer portion has a hard layer to have strength, and the inner layer portion has a triple structure in which the density is lowered to give elasticity. As a result, since the hard layer on the surface has excellent compression resistance, the impact of the dent is absorbed by the elastic layer inside and does not reach the inside of the fiber filling body. Moreover, even if it dents, it can be a fiber-filled body which has a quick recovery power and is durable and has little settling even after long-term use.

Claims (2)

[Claims] 1. A fiber packing having a packing density of 25 to 80 g / 1000 cm ³ formed by laminating thin-layer webs mainly composed of short fibers, the packing having a higher hardness than the inner layer. A fiber-filled body characterized by having an elastic recovery rate of 85% or more with respect to a high compression load, and having a residual compression strain of 25% or less at 70 ° C. 2. The fiber filling body according to claim 1, wherein both the surface layer portion and the inner layer portion include heat fusion fibers, and the surface layer portion is fused more than the inner layer portion.