JPH0754254A - Sheet-like heat insulating material - Google Patents

Abstract

PURPOSE: To provide sheet-form insulating material having excellent insulation efficiency even under a low density condition by mixing melt blown fine fibers and down with the specified ratio. CONSTITUTION: Sheets for insulating material having a basis wt. of 35-250 g/m<2> and a density of <=10 kg/m<3> are obtained by melting polypropylene resin, simultaneously spraying toward a collector 10 as melt blown fine fibers of a mean diameter of <=10 μm via a die 10, discharging downwards down 17 charged in a hopper of a blower 15 by a fun 16 via a nozzle 19, and mixing in a range of the prescribed melt blown fine fibers of 30-85 wt.% and the down 17 of 15-70 wt.%, and collecting on a collector roll 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like heat insulating material which can be used for clothing or bedding such as ski wear and for industrial applications.

[0002]

2. Description of the Related Art Filling materials such as down and non-woven fabric made of synthetic short fibers (staple fibers) are widely used as heat insulating materials for clothing and the like. Of these, down is a heat insulating material that is unique in that it has excellent heat insulating properties and is lightweight (density about 3 kg / m ³ ).

However, down has a problem that workability and workability are poor. That is, the down is easily scattered, and it requires skill to handle the down, and the scattered minute down deteriorates the working environment, which is extremely painful for the worker. Furthermore, when using down as a heat insulating material for clothing, the down is cut, or the outer cover is stitched, and the down is evenly placed in bag-shaped fabric divided into a plurality of small chambers. Although it requires a step of inserting, there is a problem that the work is extremely difficult and complicated.

Therefore, various attempts have been made to improve down in order to solve the drawbacks of down.

US Pat. No. 4,118,531 discloses a heat insulating material obtained by intertwining meltblown fine fibers obtained by blowing a fibrous material forming material into a high-speed gas and synthetic short fibers. Although this heat insulating material is excellent in workability and workability, it does not have sufficient heat insulating property in a low density state below 10 kg / m ³ . Therefore, it is not possible to obtain good comfort and excellent heat insulation even when used for winter clothes.

JP-A-54-27069 discloses that feathers are driven into a base cloth made of shrinkable fibers by a hydroentangling method and then the base cloth is contracted with hot water to fix the feathers to the base cloth. , A sheet-like article having at least one surface covered with feathers. However, the present invention aims at decorative improvement of the texture of the base fabric, and since the weight ratio of the base fabric to the feathers is high, the obtained sheet-like material has a high density. Therefore, this method cannot provide a heat insulating material having a low density and excellent heat insulating properties, which is the object of the present invention.

Japanese Unexamined Patent Publication (Kokai) No. 59-194781 discloses a sheet-like structure in which a small group of feathers or the like is sandwiched from both sides with a thin-film web of long fibers and laminated. However, the feathers inside the feather layer cannot be sufficiently brought into close contact with the web by the process of heating and pressing the web of the heat-meltable material on the feathers stacked in layers. Therefore, the adhesion between the long fibers of the web and the feathers becomes insufficient, and it is difficult to sufficiently prevent the feathers from scattering. Further, the structure having the feather layer between the laminated webs has a problem that it is weak against the force particularly in the direction of peeling the webs.

Japanese Unexamined Patent Publication No. 59-22088 discloses a feather and a sheet-like material in which feathers and long fibers are intertwined with each other. The long fibers here are fibers such as wool, silk, linen, and cotton. Therefore, here, a heat insulating material in which lightness is particularly taken into consideration cannot be obtained. Further, since the disclosed entanglement method is based on disturbance by a cotton maker, the entanglement between the long fibers and the feathers is insufficient. Therefore, separation of long fibers and feathers occurs, resulting in poor workability and processability.

[0009]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art.
Has excellent heat insulation in the low density state of kg / m ³ or less,
Another object of the present invention is to provide a heat insulating material having excellent workability and workability and a sheet material obtained by processing the heat insulating material.

[0010]

The present invention has an average diameter of 10
A sheet-shaped heat insulating material composed of melt blown fine fibers having a size of μm or less and down, and the above-mentioned object is achieved by such a constitution.

The melt-blown fine fiber referred to here is
Fibers made by the melt blown method in which fibers are formed by blowing molten material into a high velocity gas through a molding orifice. The melt blown method is described in detail, for example, in Industrial and Engineering Chemistry Vol. 48, No. 8, pp. 1342 to 1346.

The meltblown fine fibers used in the present invention should have an average diameter of 10 μm or less. This is because when the average diameter exceeds 10 μm, the density becomes high and the weight of the sheet-shaped heat insulating material becomes heavy as a result, and the surface area per unit weight becomes small, which may result in insufficient entanglement with down. This is because. Examples of the material of the meltblown fine fiber include materials that can be melted and blown out by the meltblown method, and specifically, polypropylene, polyethylene, polyethylene terephthalate, polyamide, polyvinyl chloride, acrylic resin, polystyrene, polysulfone and the like. Used. In particular, polypropylene is suitable because it has a low melting temperature, excellent mechanical strength, and low cost. In the present invention, these resins can be used alone or in combination.

[0013] Generally, down refers to a soft, fluffy fiber that grows primarily under the feathers of waterfowl such as geese and ducks. However, in the present specification, the present invention is not limited to these, and the feathers of water birds and livestock, which have excellent heat insulation properties comparable to down, and mixtures thereof with down are also included in the meaning of the term “down”.

In general, since melt-blown fine fibers have a small fiber diameter and a large surface area, they easily enter into a certain mass of down fibers and are entangled sufficiently and firmly, while using a heat insulating material or during processing. There is no separation inside. When down is brought into contact with the fibers in a semi-molten state by selecting manufacturing conditions, the meltblown fine fibers partially penetrate into the inside of the down fibers, and a stronger entanglement can be formed.

An example of a method for intertwining meltblown fine fibers and down is shown in FIG. First, the down 17 is filled in the hopper 18 of the blower 15. The down 17 filled in the hopper 18 is discharged downward from the nozzle 19 by the fan 16 at a constant speed. On the other hand, the meltblown fine fiber material described above is loaded into an extruder, melted, and extruded through the orifice of the die 10. Usually, the die 10 also has an orifice for blowing heated air at a high speed in addition to the orifice for extruding the meltblown fine fibers, and the extruded meltblown fine fibers are blown toward the collector by the air flow sent through the orifice. The meltblown fine fibers are further refined and solidified in the meantime.

The down 17 and meltblown fines discharged from nozzle 19 and die 10, respectively, are mixed in a high velocity air stream. Since the melt blown fine fibers discharged from the die 10 are in a molten state, they are intertwined with the down 17 while solidifying. The formed meltblown fine fiber and down mixture 20 is a collector roll composed of a mesh plate with fine perforations placed in front of the orifice.
Captured on 14. The sheet-like heat insulating material of the present invention can be obtained by winding the collected mixture.

In the heat insulating material obtained by the present invention, it is preferable that the down and the melt blown fine fibers are physically sufficiently intertwined with each other. If this is not the case, the workability and workability may be deteriorated due to separation and scattering of down during use. Further, the amount of down held in the heat insulating material is reduced, and as a result, the heat insulating property is also lowered.

In order to provide sufficient entanglement between the down and the meltblown fine fibers, it is preferable to weld a part of the meltblown fine fibers and the down. Therefore, when mixing down and meltblown fine fibers, it is preferable that the fine fibers are mixed in a semi-molten state.

The mixing ratio of down can be changed by changing the ratio between the amount of down supplied to the blower 15 and the amount of melt blown fine fibers discharged from the extruder. In the present invention, the meltblown fine fibers are preferably used in an amount of 30 to 85% by weight, more preferably 40 to 75% by weight. When the amount of the meltblown fine fibers used is less than 30% by weight, the meltblown fine fibers and the down are not sufficiently entangled with each other, and thus the obtained heat insulating material is inferior in workability and processability. When the amount of the meltblown fine fibers used exceeds 85% by weight, the content of down is insufficient, so that a low-density heat insulating material of 10 kg / m ³ or less cannot be obtained. Further, it is preferable that the amount of the meltblown nonwoven fabric used is 40 to 75% by weight because the density of the heat insulating material can be 5 Kg / m ² or less, and it is particularly lightweight and excellent in heat insulating property. This is because a heat insulating material having good properties can be obtained.

On the other hand, the blending ratio of down is 15 to 70% by weight,
It is preferably 25 to 60% by weight. This is because if the down content is less than 15% by weight, a heat insulating material having sufficient heat insulating properties in a low density state cannot be obtained, as described above. Further, when the down content is more than 70% by weight, not only the workability and workability of the obtained heat insulating material are deteriorated but also the obtained heat insulating material becomes expensive.

It is preferable that the amount of down used is 25 to 60% by weight, if the density is within this range, the density of the heat insulating material is 5 kg / m ²
This is because it is possible to obtain the following, and in particular, it is possible to obtain a light-weight heat insulating material having excellent heat insulating properties and good workability.

The basis weight of the sheet-shaped heat insulating material of the present invention can be easily adjusted by changing the rotation speed of the collector roll. Here, the basis weight of the sheet-shaped heat insulating material is 35-
A range of 250 g / m ² is suitable. This is because if it is less than 35 g / m ² , the physical strength becomes insufficient and the heat insulating property becomes poor. Further, when the basis weight exceeds 250 g / m ² , the workability becomes poor due to being too heavy, and the clothes using such a sheet-shaped heat insulating material become uncomfortable to wear.

According to the present invention, a sheet-like heat insulating material having an excellent heat insulating property of 24 clo / kg / m ² or more is obtained in this way.

[0024]

The present invention will be explained in more detail by the following examples, but the present invention is not limited thereto.

According to the conditions shown in Table 1 below, FIG.
A heat insulating material having a basis weight of 35 to 250 g / m ² was prepared by the method shown in.

In this example, polypropylene was used as the material for the meltblown fine fibers. In addition, duck down containing feathers was used as down.

In this example, the density was calculated by the following formula from the thickness and the weight per unit area measured on a sample of 21 cm × 21 cm under a load of 0.0002 psi (pounds per square inch). Density (kg / m ³ ) = 0.0002 psi sample thickness (m) / basis weight
(g / m ² )

The load when measuring the thickness of a low-density nonwoven fabric is generally 0.002 psi, but when the thickness is very low, such as the sheet-shaped heat insulating material of the present invention, the thickness when the load is not applied. A change of 0.0002 psi was used because the change in was too large.

The adiabatic efficiency per weight was calculated from the following equation. Adiabatic efficiency per weight (clo / kg / m ² ) = Insulation value of sheet insulation (clo) / Weight per unit area (kg / m ² ) clo (insulation value) is generally used as the insulation value of clothes. It is a unit that is used, and is physically 1clo = 0.18 ℃ ・ m ²・ hr / kcal. The measurement was performed according to ASTM C-518 using Rapid-K manufactured by Holometrix Inc.

[0030]

[Table 1] Sample blending ratio (wt%) Density Adiabatic efficiency number Fiber down (kg / m ³ ) (clo / kg / m ² ) 1 86 14 7.2 19.8 2 85 15 8.9 13.2 3 73 27 5.3 24.1 4 68 32 3.5 31.5 5 66 34 3.9 25.1 6 53 47 4.0 34.9 7 50 50 3.8 29.5 8 45 55 4.1 31.7 9 30 70 3.5 33.5 10 25 75 4.0 --11 16 84 6.1 --In the table, fiber means meltblown fine fiber .

The relationship between the mixing ratio of meltblown fine fibers and down and the density of the obtained heat insulating material is shown in the graph of FIG. As shown in this graph, when the mixing ratio of down constituting the heat insulating material of the present invention was 15% by weight or more, the low density heat insulating material of 10 kg / m ³ or less, which was the object of the present invention, was obtained. Even with a mixing ratio of 70% by weight or more, a heat insulating material having a density of 10 kg / m ³ or less was obtained, but the strength was insufficient and it was not practical in workability and workability.

The evaluation of the physical properties in this example is carried out in a basis weight of 35-
It was made within a 250 g / m ² but, 35 g / m ² or less of the weight per unit area of the sheet-like heat insulating material can not be wound physical strength is insufficient, 250 g / m ² or more The product itself was inferior in workability and workability because it was too heavy and broke during work.

The relationship between the mixing ratio of meltblown fine fibers and down and the adiabatic efficiency per weight is shown in the graph of FIG. A good thermal insulation efficiency per weight was obtained when the down mixture was 15% by weight or more, and an excellent thermal insulation efficiency per weight of 24 clo / kg / m ² or more was obtained especially when the mixing ratio was 25% by weight or more.

[0034]

EFFECTS OF THE INVENTION A heat insulating material having excellent heat insulating property in a low density state of 10 kg / m ³ or less, and excellent workability and workability, and a sheet material obtained by processing the heat insulating material are provided.

[Brief description of drawings]

FIG. 1 illustrates an example of a method of providing entanglement of meltblown fine fibers and downs.

FIG. 2 is a graph showing the relationship between the mixing ratio of meltblown fine fibers and down and the density of the obtained heat insulating material.

FIG. 3 is a graph showing the relationship between the mixing ratio of meltblown fine fibers and down and the adiabatic efficiency per weight.

[Explanation of symbols]

 17 ... Down, 20 ... Meltblown fine fiber, 15 ... Blower, 10 ... Die, 14 ... Collector roll, 16 ... Fan.

Claims (5)

[Claims] 1. A sheet-shaped heat insulating material comprising meltblown fine fibers having an average diameter of 10 μm or less and down. 2. The sheet-shaped heat insulating material according to claim 1, comprising 30 to 85% by weight of the meltblown fine fibers and 15 to 70% by weight of the down. 3. The sheet-shaped heat insulating material according to claim 1, wherein the melt-blown fine fiber is a polypropylene resin. 4. The density is 10 kg / m ³ or less.
The sheet-shaped heat insulating material according to any one of 1. 5. The unit weight is 35 to 250 g / m ² .
The sheet-shaped heat insulating material according to any one of 4 above.