JP2006241637A - Nonwoven fabric magnetic member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric magnetic member used on the integral foam molding of a nonwoven fabric with a polyurethane, in more detail, the nonwoven fabric magnetic member with which the nonwoven fabric can simply and accurately be fixed to the inside of a foaming mold. <P>SOLUTION: This nonwoven fabric magnetic member is characterized by spray-coating and drying an acrylic emulsion on the surface of a substrate 1 comprising the nonwoven fabric to dispose the resin coating film 2, and then roll-coating and drying an acrylic emulsion mixed with iron powder, such as soft iron, hard iron, cast iron, or reduced iron, having an average particle size of 15 to 400 μm on the resin coating film 2 to dispose the magnetic layer 3. A release paper 5 may be adhered to the back side of the substrate 1 through an adhesive layer 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a non-woven magnetic body used when integrally forming a fiber-based nonwoven fabric with urethane, and more specifically, the fiber-based nonwoven fabric can be easily and accurately fixed at a predetermined position in a urethane foam mold. It is related with the magnetic material made from a nonwoven fabric.

  2. Description of the Related Art Conventionally, as a cushion material for various sheets, for example, a nonwoven fabric made of fiber (such as felt and nonwoven fabric) (hereinafter referred to as a nonwoven fabric) integrally foam-molded on the surface of a urethane foam has been widely used. When molding such a non-woven fabric integrally foamed molded product, it is necessary to fix the non-woven fabric at a predetermined position in the foam molding die. For this reason, as shown in, for example, Patent Document 1 and Patent Document 2, foaming is performed. A method is adopted in which permanent magnets are arranged at predetermined positions in the mold, while magnetism is imparted to the nonwoven fabrics, and both are joined by magnetic force to fix the nonwoven fabrics at predetermined positions in the foam mold. It has been.

However, according to the conventional method, it can be applied to a foam mold with a relatively simple surface shape, but it is difficult to fit non-woven fabrics in a complicated shape or a three-dimensional deeply recessed part. The problem is that the above-mentioned restrictions are imposed, and the bonding force between the nonwoven fabric and the mold surface is weak, and the urethane foam solution penetrates and solidifies on the back side of the nonwoven fabric, causing abnormal noise when using the sheet. there were. For this reason, thin steel tape magnetic materials such as ferrite and rare earth elements, which are strongly magnetic and resistant to rust, are used on non-woven fabrics with adhesives, etc., but this is very expensive. In addition, it has been found that it contains hexavalent chromium, which is an environmentally hazardous substance, and a problem has arisen that it has become unusable from the environmental aspect.
JP 2001-252930 A JP 2002-120236 A

  The present invention solves the above-described problems and is a foam mold having a complicated shape, a three-dimensionally deeply recessed portion, and the like, applied to the nonwoven fabric when the nonwoven fabric is integrally foam-molded. However, non-woven fabrics can be fixed easily and accurately along the mold surface, and the non-woven fabrics and the mold surface also have strong adsorption power, which reliably prevents the urethane foam solution from entering the back side of the non-woven fabrics. Further, the present invention has been completed for the purpose of providing a non-woven magnetic material that is inexpensive and excellent in handleability.

The non-woven fabric magnetic body of the present invention made to solve the above problems forms a resin film formed by coating an acrylic emulsion solution at a rate of 50 to 250 g / m ^{2 in} advance on a base material surface made of a non-woven fabric and drying it. In addition, 200 to 500 g of a solution in which an amorphous iron powder having an average particle size of 15 to 400 microns and no corners is mixed in a highly viscous or thickened acrylic emulsion solution having a viscosity of 4000 to 15000 cps on the surface of the resin coating. A magnetic layer having a high magnetic flux density is provided on the surface of the substrate by uniformly applying and drying at a rate of / m ² .

The non-woven fabric magnetic body of the present invention forms a resin film obtained by coating and drying an acrylic emulsion solution at a rate of 50 to 250 g / m ² in advance on the surface of a base material made of non-woven fabric. A uniform viscosity of 200 to 500 g / m ² is uniformly applied to an acrylic emulsion solution having a high viscosity or a viscosity of 4000 to 15000 cps mixed with an amorphous iron powder having an average particle size of 15 to 400 microns. A foam-molding die that has three-dimensionally deeply recessed parts, etc. at the time of nonwoven foam integrated foam molding because it has a structure in which a magnetic layer with a high magnetic flux density is provided on the surface of the base material by drying. Even so, various non-woven fabrics can be fixed along the mold surface, and the adsorption force between the non-woven fabrics and the mold surface is strong. Input is also able reliably prevented.
In addition, although the adsorption strength by the permanent magnet of the product of the present invention does not reach that of an expensive steel sheet, it can be confirmed that the adsorption power is about 50% larger than that of the non-woven magnetic material currently used in some parts. (See Table 1 below).

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for explaining the structure of the present invention. In the figure, 1 is a base material made of nonwoven fabric, 2 is a resin coating as a bonding layer, and 3 is a magnetic layer. is there. 2 shows another embodiment, FIG. 3 shows a perspective view of FIG. 2, in which 4 is an adhesive layer, 5 is a release paper, and 6 is a half cut.

  The non-woven fabric magnetic material of the present invention is a soft iron having an average diameter of 15 to 400 microns (μm) through a resin coating 2 formed by spraying and drying a general-purpose acrylic emulsion solution on the surface of a base material 1 made of non-woven fabric. The magnetic layer 3 is formed by roll-coating and drying an acrylic emulsion adhesive solution or a solution obtained by mixing iron powder such as hard iron, cast iron, and reduced iron in an acrylic emulsion solution.

The base material 1 holds the magnetic iron powder uniformly on the surface of the fiber, is flexible enough to adapt to the complex shape of the foaming mold and the three-dimensional uneven surface, and is easy to handle when pasting. It has moderate rigidity and is used for integral foam molding by firmly fixing the nonwoven fabric in place when it is attached to the appropriate location of the nonwoven fabric to be integrally foam molded and set in a foam mold. Yes, it becomes completely unnecessary after molding. For this reason, inexpensive non-woven fabrics have attracted attention as a magnetic base material, but it is difficult to form a uniform and dense metal particle layer on the surface to obtain a good adsorbing force with a permanent magnet. Currently, it is not widely used.
Therefore, the present inventor conducted intensive research on a method for forming a uniform and dense metal particle layer on the surface of a base material composed of a specific nonwoven fabric of fine fibers, and as a result, provided a specific magnetic layer via a resin film. As a result of the structure, it has been found that a uniform and dense layer of metal particles can be formed on the surface of the nonwoven fabric as much as possible, and the present invention has been completed.

The base material 1 is preferably composed of a thin long fiber having a denier of 1 to 5 denier, preferably 1.5 to 3 denier, and a nonwoven fabric having a basis weight of 45 to 85 g / m ² , preferably 60 to 70 g / m ^2. .
The nonwoven fabric used as the base material 1 is necessary only when fixing the nonwoven fabric for urethane integral foam molding to the mold, and almost no strength is required. Therefore, the fiber may be a relatively thin fiber of 4 denier or less. Fibers are preferred. In addition, as the fiber material, inexpensive regenerated fibers of various synthetic fibers such as polyester can be used.

As the non-woven fabric, those made of the same kind of fibers, mixed fibers or regenerated fibers are used, but in order to keep the magnetic iron powder in a good state on the fiber surface and to obtain a strong bonding force, the fiber is 1 It has been found that a fine fiber of ˜4 denier and a basis weight in the range of 45 to 86 g / m ² are necessary. If the fiber is larger than 4 denier and the basis weight is less than 45 g / m ² , the iron powder almost slips out to the back surface, making it difficult to efficiently keep it on the surface of the fiber, which causes a decrease in magnetic attractive force. On the other hand, if the basis weight is larger than 85 g / m ² , the impregnation of an acrylic emulsion adhesive solution containing iron powder, which will be described later, deepens into the interior and the drying time becomes longer, resulting in a significant decrease in productivity and a complicated three-dimensional surface. This is because the flexibility that is easy to adjust decreases and iron powder penetrates into the inside of the nonwoven fabric so that it becomes difficult to form a dense metal layer on the surface, which makes it impossible to obtain a stronger magnetic layer.

The resin coating 2 is formed by spray-coating and drying a normal acrylic emulsion solution.
The base material 1 made of nonwoven fabric is preliminarily roll-coated by spraying and drying a solution such as a general-purpose acrylic emulsion at a rate of 50 to 250 g / m ² to form a thin resin film 2 on the fiber surface. In order to make it easy to roll coat by making it difficult for the acrylic emulsion solution and iron powder particles mixed with the iron powder to penetrate deep into the fiber layer, the metal powder particles remain on the fiber surface as much as possible. Here, the absorption of the coating weight of the acrylic emulsion solution had a ratio of 50 to 250 g / m ² can not sufficiently resin coating is less than 50 g / m ^2, the fibers of the acrylic emulsion solution mixed with iron powder On the other hand, when the coating amount is more than 250 g / m ² , the flexibility of the nonwoven fabric is hindered and a good effect cannot be obtained.
This combined with the effects of the fiber thickness of the present invention, the nonwoven fabric weight, the average particle size of the iron powder, the mixing ratio of the iron powder, the viscosity of the acrylyl emulsion solution or the adhesive solution, the coating amount, etc. A high-capacity iron powder layer is formed on the surface of the non-woven fabric, and a good adsorption force with the permanent magnet can be obtained even with a magnetic material of iron powder.

The magnetic layer 3 has an average particle size of 15 to 400 microns (μm), and an iron emulsion such as normal soft iron, hard iron, cast iron, and reduced iron other than magnetic materials such as ferrite and rare earth element oxides. A solution or a solution mixed in an acrylic emulsion adhesive solution is roll-coated and dried.
More specifically, an iron-based fine particle having an average particle size of 15 to 400 microns (μm) and having an irregular shape with a corner is 50 to 90% by weight, preferably 60 to 70% by weight. The mixture is mixed with an emulsion solution or an acrylic emulsion adhesive solution, and roll-coated on the substrate 1 at a rate of 200 to 500 g / m ² , preferably 250 to 400 g / m ² and dried.

At this time, before mixing the iron powder particles, the acrylic emulsion solution has a high viscosity of 4000 to 15000 cps, or the viscosity is adjusted with ammonia water, so that the mixed solutions having different specific gravities are uniformly and on the substrate. If the powder is controlled so that it is uniformly applied without impregnating too much, and drying is performed so that the iron powder particles stay on the upper surface of the fiber as uniformly as possible, a dense and thin iron powder layer of magnetic material is formed and molded. It was clarified that the entire surface comes into contact with the permanent magnet attached to the mold and a good attractive force can be obtained.
If the average particle size of the iron powder is less than 15 microns (μm), the ratio of entering into the fiber material becomes large, and a large amount of iron powder is required to form a good iron powder surface, resulting in high costs. On the other hand, if the average particle size is larger than 400 microns (μm), the contact area with thin fibers becomes small and the iron powder is easy to peel off, and the iron powder overlaps and the arrangement tends to be non-uniform, and the adsorptivity to the permanent magnet is low. There is a risk of decline.
The viscosity of the acrylic emulsion solution used as the binder of iron powder is adjusted to 4000-15000 cps, and the iron powder adheres to the surface of the fiber as uniformly as possible while reducing the intrusion into the inside of the fiber material. Yes. If the viscosity is less than 4000 cps, the coating on the surface of the iron powder becomes thinner and better, but the penetration into the fiber material tends to increase, and the bondability with the surface of the fiber material with the fine iron powder tends to decrease, and it tends to peel off. There is.

In addition, 0.8 to 1.5% by weight of nitrite may be added to the magnetic layer 3.
It is generally known that when iron powder is mixed and applied to an acrylic emulsion solution, the iron powder becomes very rustable by the surfactant in the acrylic emulsion after drying. There are various ways to prevent this, but it is the cheapest to add sodium nitrite, and if this is added at a ratio of 0.8 to 1.5% by weight, the rust caused by the iron powder acrylic emulsion In addition to preventing the occurrence, there is an advantage that the viscosity of the acrylic emulsion solution is slightly increased, and there is also an advantage that the thickening operation with ammonia water becomes easier and the workability is improved.

Moreover, as shown in FIG. 2 and FIG. 3, the release paper 5 can also be stuck on the back surface of the base material 1 through the adhesive layer 4. Further, a half cut for separating into an arbitrary shape can be formed and adhered.
The pressure-sensitive adhesive layer 4 is formed by applying and drying a general acrylic pressure-sensitive adhesive on the back surface of the substrate 1, and then attaching the release paper to a size that is easy to use so that the release paper 5 is not cut off. It is preferable to improve the usability by making a half-cut (cut) and making the nonwoven magnetic material easily peel off. The half-cut shape can be processed into a free shape such as a triangle, a square, a round shape or a tape shape suitable for the shape of the permanent magnet attached to the foaming mold.

Next, the example of shaping | molding the nonwoven fabric magnetic body of this invention is demonstrated.
Fabricate a non-woven fabric with a constant width of 45-85 g / m ^{2 with} a basis weight of 45 to 85 g / m ² made of a regenerated product with a relatively long fiber or a newly mixed product with a fiber of 4 denier or less of various synthetic fibers such as polyester. Then, a solution such as an acrylic emulsion is applied to the surface in advance at a rate of 50 to 250 g / m ² by spray coating or the like, and a thin resin film is formed on the fibers on the surface of the nonwoven fabric.

Next, 50 to 90% by weight of iron powder having an average particle size of 15 to 400 microns (μm) was added onto the nonwoven fabric to an acrylic emulsion solution whose viscosity was adjusted to 4000 to 15000 cs in advance with ammonia water and stirred for 5 minutes. Thereafter, sodium nitrite, which is a rust inhibitor, is added at a rate of 0.8 to 1.5% by weight, and after each plate for 5 to 10 minutes, it is applied onto the nonwoven fabric by roll coating at a rate of 200 to 500 g / m ^2. Apply.

After coating, the film is sufficiently dried at 60 to 150 ° C., and an ordinary pressure-sensitive adhesive such as acrylic is applied to the back side of the nonwoven fabric substrate and dried, and an ordinary release paper is pasted thereon. Furthermore, half-cut into a shape of a necessary size so that the release paper is not cut, so that the non-woven magnetic material can be easily peeled off.
The non-woven fabric magnetic material obtained in this way is peeled off from the release paper at the time of use, and a required quantity of non-woven fabrics for urethane-integrated foam molding is attached to a designated position, and is pre-installed in the foam mold. Then, the permanent magnet is set and fixed at a predetermined position, and a urethane foam compounding liquid is injected to be used for molding a urethane foam molded product integrated with a nonwoven fabric.
The obtained results are shown in Table 1.

  As is clear from the above description, the present invention provides a resin film obtained by spray-coating and drying an acrylic emulsion solution on the surface of a substrate made of nonwoven fabric, and the average particle size is 15 to 400 microns ( μm) soft iron, hard iron, cast iron, reduced iron, etc. mixed in an acrylic emulsion solution is roll-coated and dried to provide a high-density magnetic layer on the surface of the nonwoven fabric. Even foamed molds with complex shapes and three-dimensionally deeply recessed parts can easily and accurately fix non-woven fabrics along the mold surface and adsorb non-woven fabrics to the mold surface. The force is also strong, and the urethane foam solution can be reliably prevented from entering the back side of the nonwoven fabric. Furthermore, it has the advantage of being inexpensive and excellent in handleability.

It is a schematic sectional drawing which shows embodiment of this invention. It is a schematic sectional drawing which shows other embodiment. FIG. 3 is a perspective view of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Resin film 3 Magnetic layer 4 Adhesive layer 5 Release paper 6 Half cut

Claims (4)

A non-woven fabric substrate surface is preliminarily coated with an acrylic emulsion solution at a rate of 50 to 250 g / m ² and dried to form a resin film. The surface of the resin film has a high viscosity or an increase of 4000 to 15000 cps. A solution obtained by mixing an amorphous iron powder having an average particle size of 15 to 400 microns and no corners in a viscous acrylic emulsion solution is uniformly applied at a rate of 200 to 500 g / m ² and dried to form a substrate surface. A magnetic material made of nonwoven fabric, comprising a magnetic layer having a high magnetic flux density. Nonwoven, with 1-4 denier thin long fibers made of synthetic fibers such as polyester, nonwoven magnetic body according to claim 1 having a basis weight is of the 45~85g / m ^2.   The nonwoven fabric magnetic body according to claim 1 or 2, wherein 0.8 to 1.5 wt% of nitrite is added to the magnetic layer. The nonwoven fabric magnetic body according to any one of claims 1 to 3, wherein a release paper is adhered to the back surface of the base material via an adhesive layer, and a half cut is formed for cutting into a desired shape.

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