JPH01299026A - Permeable inorganic powder body sheet and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a permeable inorganic powder body sheet whose mechanical strength is high by enlarging a surface area of the inorganic powder body, by a method wherein a powder body mixture containing an inorganic powder body and thermoplastic resin powder body at a specific ratio is interposed between a surface layer comprised of a permeable base material containing split fiber nonwoven cloth and a back side layer comprised of an impermeable or permeable base material and fused thermally. CONSTITUTION:A powder body mixture is comprised of a 75-95wt.% inorganic powder body and 25-5wt.% thermoplastic resin powder body. The powder body mixture is supplied to a hopper 4 and continuously onto nonwoven cloth or impermeable sheet led by a drawing-out roll 2 through a slit on the lower end of the hopper 4. Then it is dispersed evenly in a widthwise direction on the nonwoven cloth by making use of a doctor knife 5. Thus the powder body mixture is interposed between an impermeable base material from drawing out rolls 1 and 2 or a permeable base material and a permeable base material backed with split fiber nonwoven cloth. Then the same is led to a heated press roll 3. The press roll 3 is preheated at a temperature of at least the softening point of a used thermoplastic resin powder body, preferably at least the melting point.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a breathable inorganic powder sheet imparted with conductivity, magnetism, deodorizing properties, bactericidal properties, antibacterial properties, etc., and a method for producing the same.

[Prior art] Conventionally, commercially available conductive sheets and magnetic sheets are made by blending carbon black or metal powder with thermoplastic resin to form a sheet, or by forming the surface of a thermoplastic resin sheet that has been formed into a sheet in advance. A method of applying conductive paint or the like is adopted.

Although these sheets contain a large amount of inorganic powder, not only the effect is small but also the mechanical strength of the sheet decreases. It also has poor breathability.

On the other hand, inorganic powders having properties such as deodorizing properties, bactericidal properties, and antibacterial properties are used by enclosing the powders in air permeable containers, bags, and the like. There are also examples in which thermoplastic resin is blended with inorganic powder as described above and used as fibers and sheets. However, such sheets and the like have the same problems as described above.

In particular, for inorganic powders that have properties such as deodorizing properties, bactericidal properties, antibacterial properties, and drying properties, it is preferable that they have a large surface area, so the effectiveness of blending them into thermoplastic resins will be significantly reduced.

[Problems to be solved by the present invention] The present invention was made as a result of intensive studies to solve the above-mentioned problems, and its purpose is to increase the surface area of inorganic powder as much as possible, The present invention provides an air-permeable inorganic powder sheet with high mechanical strength that maximizes body performance, and a method for producing the same.

[Means for Solving the Problems] A first aspect of the present invention provides an inorganic powder between a surface layer made of a breathable base material containing split fiber non-woven material 1j and a back layer made of an impermeable base material or a breathable base material. Body 75-95% by weight and heatable l
This is a breathable inorganic powder sheet formed by heat-sealing a powder mixture containing 25 to 5% by weight of a synthetic resin powder.

The second invention of the present invention is characterized in that 75 to 95% of inorganic powder and 9% of heat 1 This is a method for producing a breathable inorganic powder sheet, characterized in that a powder mixture containing 25 to 5% by weight of plastic resin powder is interposed in a layer and heat-sealed.

The split fiber nonwoven fabric of the present invention refers to a split film obtained by splitting a stretched and/or rolled thermoplastic resin film, and a Jl! It is a laminated body made of a stretched laminate, a stretched tape and/or a rolled tape of a thermoplastic resin film, and the air permeable base material including split fiber nonwoven fabric used for the surface layer is paper, natural fiber, thermoplastic resin, etc. The split fiber nonwoven fabric is laminated on a breathable sheet such as a nonwoven fabric, woven fabric, foam sheet, thermoplastic resin sheet, perforated sheet such as metal foil such as aluminum foil,
Includes paper made from split fiber nonwoven fabric with valves and the like.

The impermeable base material of the present invention includes a thermoplastic resin sheet,
Customary sheets such as metal foil can be used. Moreover, the materials mentioned above can be used as the breathable base material of the back layer, and any of these materials may be used to reinforce the split fiber nonwoven fabric in the same way as the surface layer, and if economic efficiency is not taken into account, this is preferable.

The inorganic powder of the present invention includes carbon black, graphite, activated carbon, zeolite, zeolite bonded with metal ions, silica, iron, and stainless steel.

It represents at least one kind selected from metal powders such as aluminum, nickel, copper, gold, silver, tin, zinc, and ferrite, and several kinds can be used in combination depending on the purpose, use, etc.

Specific examples of the characteristics of the inorganic powder are generally as follows.

(+) Conductivity: carbon black, graphite,
Metal powders such as mica, iron, stainless steel, aluminum, nickel, copper, gold, silver, tin, zinc, ferrite, etc. Conductive mica, etc. (2) Magnetic...Magnetic iron powder, ferrite, etc. (3) Deodorizing properties, adsorption properties ...Activated carbon, zeolite, etc. (4) Germicidal, antibacterial properties ... Zeolite supporting metal ions such as copper, gold, silver, lead, lead, tin, bismuth, cadmium, chromium, cobalt, nickel, etc. (5) ) Insect repellent and insecticidal properties: Inorganic powder impregnated with, supported on, or coated with chemicals such as insect repellents and insecticides (6) Drying property: Silica gel, etc. These inorganic powders deviate from the gist of the present invention. If not, the above example does not matter.

In addition, the particle size of the powder described in -F is preferably 0.1 to 300 μm, although the larger the surface area, the more preferable it is, but considering the handling of the powder, etc.
, preferably 0.1-100 μm, more preferably 50 μm or less. More specifically, preferred particle size ranges include activated carbon, activated clay, carbon black, etc.
50μm, 10-100μm of zeolite, magnetic iron powder, etc.
is within the range of

The thermoplastic resin powder of the present invention includes low, medium and high density polyethylene, polypropylene, polybutene-1, poly-
Homopolymers such as 4-methyl-pentene-1, ethylene and propylene, 1-butene, 4-methyl-1-pentene,
Alternating copolymers with α-olefins such as 1-hexene and 1-octene, ethylene-unsaturated carboxylic acids such as ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, and ethylene-ethyl acrylate copolymers. polyolefin resins such as copolymers with or derivatives thereof, homopolymers and/or copolymers modified with unsaturated carboxylic acids or derivatives thereof, or mixtures thereof;
Examples include polyamide resin, polyester resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyphenylene oxide, polyphenylene sulfide, polycarbonate, polyacetal, fluorine resin, ABS, polyurethane, etc. Among these, polyolefin resins are preferred because they are inexpensive and have excellent mechanical strength. In particular, homopolymers or copolymers of ethylene and propylene are most preferred.

Considering the dispersion when mixed with inorganic powder, the particle size of the above powder is 0.1-100 μm like inorganic powder, and even 5 μm.
A range of 0 μI or less is preferable.

The breathable inorganic powder sheet of the present invention consists of a specific ratio of the above-mentioned inorganic powder and thermoplastic resin powder between the back layer consisting of the above-mentioned breathable base material and the impermeable base material or the breathable base material. A powder mixture is interposed and heat-sealed.

That is, the powder mixture contains 75 to 95% by weight of the inorganic powder.
and 25 to 5% by weight of thermoplastic resin powder, and if the amount of inorganic powder in the powder mixture is less than 75% by weight, in other words, the amount of thermoplastic resin powder is If it exceeds 25% by weight, not only will the characteristic effects of the inorganic powder, such as conductivity and magnetism, be diluted and reduced by mixing with the thermoplastic resin, but also the resin may be formed on the surface layer of the inorganic powder. The thickness of the coating layer becomes excessive, and the characteristic effects of the inorganic powder are significantly inhibited. On the other hand, if the amount of inorganic powder exceeds 95% by weight, in other words, if the amount of thermoplastic resin powder is less than 5% by weight, the breathable inorganic powder sheet of the present invention may not be suitable for long-term recycling. This method cannot be used because the phenomenon of detachment of inorganic powder is observed when using a barb.

The above-mentioned inorganic powder and thermoplastic resin powder can be mixed using a commonly used V-type blender, ribbon blender, or Henschel blender, since both particles are ground to the same particle size and there is no problem such as classification. They can be easily mixed evenly by using a mixer or the like.

Any method can be used to interpose the powder mixture between the surface layer and the back layer, but it is important to consider the properties of the inorganic powder shown in the specific examples above, such as conductivity or deodorizing properties. Various suitable methods are adopted. That is, the combination of the air-permeable base material and the impermeable base material, the thickness and basis weight of each base material, and the method of intervening the powder mixture are also the same, but for example, the thermoplastic resin film is stretched. An example of a continuous production method in which a split fiber nonwoven fabric obtained by rolling and splitting is used as one of the breathable base materials will be explained based on the apparatus shown in FIG. 1 as follows. .

For example, a high-density polyethylene film that has been sufficiently stretched and strengthened is made into split fibers by making small cracks, and is then continuously laminated and heat-sealed in the vertical and horizontal directions.
A long roll of split fiber non-woven fabric having a ratio of 1.5 g/rrf is set on the pay-out roll 1 shown in FIG. and guide both of them between a pair of heated press rolls 3.

A powder mixture of inorganic powder and thermoplastic resin powder is supplied to a hopper 4, and is continuously fed from a slit at the lower end of the hopper to a nonwoven fabric or an impermeable sheet guided through a payout roll 2, and then to a doctor. The fibers are evenly distributed in the width direction on the non-woven fabric by using a knife 5 or the like, thus between the impermeable substrate or the breathable substrate from the pay-out rolls 1 and 2 and the breathable substrate lined with the split fiber non-woven fabric. and then guided to a heated press roll 3.

In the press roll 3, an inorganic powder sheet having a desired thickness and optionally a desired bulk specific gravity is obtained by a press roll that has been preheated to a temperature higher than the softening point, preferably higher than the melting point, of the thermoplastic resin powder used. Pressure, e.g. +, 5kg/
Under the pressure of crn', the surface layer, the back layer, and the powder mixture interposed therebetween are sandwiched and integrated.

The integrated inorganic powder sheet is guided by guide rolls 7, optionally through an annealing zone 6, and wound onto a winding roll 8. Thus usually 0.2-2 mm
, more commonly an inorganic powder sheet having a thickness such as 0.2 to 1 mm, optionally 100 to 50 mm.
08/rr+2, more commonly 130-180g/
A breathable inorganic powder sheet containing an inorganic powder such as "rn" is obtained.

The air-permeable inorganic powder sheet of the present invention obtained by the above-described method has good air permeability to the inorganic powder and a controlled amount of thermoplastic resin powder, as understood from its base material composition. Since the inorganic powder particles are fused together and the surface layer and back layer are fused together by the body, the properties of the inorganic powder, such as conductivity, deodorizing properties, and sterilizing properties, are fully maintained. able to demonstrate.

Therefore, when using a sheet of inorganic powder with deodorizing, sterilizing, and antibacterial properties in a breathable container, bag, etc., it is necessary to cut the sheet into an appropriate shape and overlap it. It can be folded into a spiral shape to increase the contact area with the fluid. In addition, when using conductive carbon black, etc., there is no restriction on the amount mixed in due to the lack of fluidity when conventional methods of kneading into thermoplastic resin are used, and the inorganic powder concentration is increased compared to the resin concentration. Since it can be formed into a film, its performance as a conductor can be improved and its uniformity can be improved. Furthermore, when using magnetic iron powder, etc., it is possible to obtain a material having sufficient flexibility by adjusting the thickness to an appropriate value, and to change the magnetic performance and other properties by laminating layers as desired. Furthermore, according to the method of the present invention, inorganic powder can be used without causing environmental pollution due to the scattering of fine particulate inorganic powder.

The properties of the above-mentioned breathable inorganic powder sheet of the present invention and examples of its applications include the following.

Conductive sheet: anti-static sheet, electromagnetic barrier sheet, r, c, substrate mat, conductive packaging material, anti-static roll mat, magnetism: magnetic mat, magnetic adhesive, magnetic medical products, deodorizing,
Adsorption properties: Refrigerator deodorizing adsorption sheets, deodorizing adsorption wall materials, water purifier filters, air purifier filters, medical deodorizing sheets, toilet deodorizing materials, bactericidal properties, antibacterial properties: Mold-preventing breathable wall materials, antibacterial sheets for refrigerators , antibacterial mat, freshness preservation sheet, insect repellent, insecticidal: insect repellent sheet, leisure river sheet, tatami underlay sheet, anti-termite sheet, drying property: desiccant sheet, drink adsorption sheet, chest of drawers,
Example 1 of closet drying sheet: 1 part of polyethylene resin (trade name: Ultrasend, manufactured by Seitetsu Kagaku ■) powder having a particle size of 10 to 50 μm and 80 f of activated carbon powder having a particle size of 10 to 30 μm. Tri-blending was performed using a V-type blender to obtain a powder mixture.

A polyester nonwoven fabric having a unit weight of 20 g/rn' was set on the feed roll 1 shown in Fig. 1, and a split fiber nonwoven fabric (
Product name: Nisseki Warif S, basis weight 23g/m'', fabric weight i [120g/rn2 backed by Kuchiki Petrochemical ■]
The nonwoven fabric was set on the feed roll 2. The powder mixture is dropped from the slit at the bottom of the hopper 4, layered uniformly in the width jT direction on the nonwoven fabric from the feed roll 1, and is smoothed to a uniform thickness with a doctor knife 5, after which the roll surface temperature is heated to 180°C. The inorganic powder sheet was sandwiched with the reinforcing nonwoven fabric from the edging roll 2 using the press roll 3, thereby obtaining an inorganic powder sheet sandwiched between the surface layer and the back layer. The roll pressure of press roll 3 in this experiment was 1.5k
g/crn''. The sheet guided from the press roll 3 further passes through an annealing zone 6 adjusted to 180°C, passes through a guide roll 7, and is transferred to a winding roll 8.
The product was rolled up into a product. The retention time in the press roll 3 and annealing zone was 3 minutes.

The thickness of this product was 0.25 n+m, the basis weight of the inorganic powder sheet was 150 g/rn'', and the basis weight of activated carbon was 120 g/rn'.

For comparison, the weight type 120g was used for roll 1 in F.
/rn' polyester nonwoven fabric was prepared and used as a comparative material.

Tensile strength and elongation (JIS L 1068-1964) and deodorizing effect tests were conducted on the above-mentioned inorganic powder sheet of the present invention and comparative materials.

1) Reagents and equipment Ammonia: Koso Chemical Co., Ltd., 28% aqueous solution Hydrogen sulfide: A gas generated by adding dilute sulfuric acid to iron sulfide was used.

Methyl mercaptan: A gas generated by adding dilute sulfuric acid to a sodium methyl mercaptan solution was used.

2) Operation The sample was cut into a size of IOX 10 cm, and one end was attached to the inner surface of a scent bag (25 x 35 cm) using double-sided tape. After heat-sealing this, 3 L (1,000 ppm) of air-based ammonia gas, 3 L (100 ppm) of hydrogen sulfide gas, or 3 L (50 ppm) of methyl mercaptan gas was sealed. This was left at room temperature, and the residual gas concentration in the bag was measured using a gas detection tube after 1, 3, 6 and 24 hours. In addition, as a blank test, the same operation was performed without adding anything.

3) Evaluation results Ammonia adsorption: (unit: ppm) Methyl mercaptan adsorption: (Qi position ppm) Hydrogen sulfide adsorption: (unit: ppm) Example 2 Polyethylene resin powder having a particle size of IO ~ 50 μm used in Example 1 A powder mixture was obtained by tri-blending 30 parts by weight and 70 parts by weight of zeolite powder having a particle size of 50 to 100 μm using a V-type blender. The back layer is made of polyethylene split woven fabric (product name: Nisseki Warif SS, Tsubo V+AG
/rn2, manufactured by Nippon Petrochemical Corporation) was set on the feed roll 1 using aluminum foil with the aluminum foil facing downward. On the other hand, polyethylene split woven fabric (product name: Nisseki Warif H3
, basis weight 34 g/rn') was set on the feed roll 2. An inorganic powder sheet was produced in the same manner as Example 1 and X except that the heating temperature was 110°C. The thickness of this material is 0.4511III1, the tsubo 111 of the inorganic powder is 160 g/m'', and the zeolite basis weight is 120 g/rn.
'.

As a material for comparison, a sheet was prepared by folding together the aluminum foil, polyethylene split woven fabric and polyethylene split woven fabric used above. A deodorizing effect test was conducted using the same JT method as in Example 1 on the inventive sheets and comparative materials, and the evaluation results are shown.

Adsorption of ammonia: (unit: ppm) Adsorption of methyl mercaptan = (unit: ppm) Adsorption of hydrogen sulfide = (unit: ppm) (Evaluation of the invention) The thermoplastic resin powder is used in the layer to reduce the amount of thermoplastic resin powder compared to the inorganic powder, allowing good contact between the inorganic powder and the outside air, so the properties of the inorganic powder such as deodorization and sterilization can be fully utilized. In addition, it is possible to sandwich and integrate fine-grained inorganic powder, which is difficult to handle, without degrading the working environment.Furthermore, if a breathable base material is used for both layers, it can be used by cutting and laminating it. This makes it possible to effectively utilize the characteristics of inorganic powder.

[Brief explanation of the drawing]

FIG. 1 shows an example of the layout of a continuous manufacturing apparatus suitable for manufacturing the breathable inorganic powder sheet of the present invention. In the figure, 1 and 2...feeding roll, 3...press roll, 4...hopper, 5...
... Doctor knife, 6... Annealing zone, 'l... Guide roll, 8... Trading roll. Patent applicant: Japan Petrochemical Co., Ltd. Agent: Patent attorney Tadashi Wakabu Figure 1

Claims (6)

[Claims] (1) Between the surface layer made of a breathable base material containing split fiber nonwoven fabric and the back layer made of an impermeable base material or a breathable base material, 75 to 95% by weight of inorganic powder and 25 to 5% of thermoplastic resin powder are mixed. A breathable inorganic powder sheet formed by heat-sealing a powder mixture containing % by weight. (2) The breathable inorganic powder sheet according to claim (1), wherein the inorganic powder is at least one selected from carbon black, activated carbon, zeolite, silica, and metal powder. (3) The breathable inorganic powder sheet according to claim (1) or claim (2), wherein the powder has an average particle size of 0.1 to 300 μm. (4) Air permeability according to any one of claims (1) to (3), wherein the split fiber nonwoven fabric is a warp-warp laminated film obtained by splitting a stretched and/or rolled thermoplastic resin film. Inorganic powder sheet. (5) The breathable inorganic powder sheet according to any one of claims (1) to (3), wherein the split fiber nonwoven fabric is obtained by laminating stretched and/or rolled thermoplastic resin film tapes in warp and warp. (6) Between the surface layer made of a breathable base material containing split fiber nonwoven fabric and the back layer made of an impermeable base material or a breathable base material, 75 to 95% by weight of inorganic powder and 25 to 5% by weight of thermoplastic resin powder are added. 1. A method for producing a breathable inorganic powder sheet, characterized in that a powder mixture containing % by weight is interposed in a layer and heat-sealed.