JP2008196072A - Base cloth for flame-retardant filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base cloth utilizable in applications in which the generation of formaldehyde becomes a problem, releasing little amount of the formaldehyde into environmental air, and especially suitable for a base cloth for a filter for air conditioning, requiring flame retardancy. <P>SOLUTION: The base cloth for the flame-retardant filter has ≥200 cc/sec/cm<SP>2</SP>air permeability and ≥5.0 mN bending resistance measured by a Gurley method, and releases ≤0.50 μg/500 cm<SP>2</SP>amount of the formaldehyde. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is composed of a synthetic resin filament and a binder component that fixes the filament to each other. More particularly, the present invention relates to a filter base fabric suitable for a melt blown nonwoven fabric base fabric used for air conditioning.

  As a method for bonding and fixing fibers in a long-fiber nonwoven fabric, a method using a binder is widely adopted, and as a binder, a method using an emulsion type adhesive resin is the most common, and a self-crosslinking resin is crosslinked. It is widely used to use a reactive group-containing resin and a crosslinking agent. These crosslinking components are methylol groups and cause formaldehyde generation.

  In recent years, there has been an increasing interest in society in relation to environmental air quality and various diseases such as allergies, and indoor air pollution problems in houses have been taken up as cases of sick house syndrome, sick building syndrome, Formaldehyde, volatile organic compounds (VOC), etc. are problems as indoor air pollutants.

In particular, formaldehyde has been clearly seen as a problem, such as the guidelines for housing in the Ministry of Health and Welfare (then) was announced in 1997, and its source is used for wood, plywood, and interior materials, which are residential building materials. It covers a wide range of fields such as adhesives, antiseptics, ant protection agents, furniture and furniture in living spaces, daily necessities, and business office equipment.
As a formaldehyde countermeasure, a method of providing a formaldehyde adsorbent (such as Patent Document 1) and a method of coating a formaldehyde adsorbent (such as Patent Document 2) are known, but they are not sufficient countermeasures.

In recent years, the problem of ozone layer destruction due to the generation of dioxins has become a social problem. Dioxins are thought to be generated from chemical substances that contain halogen elements during waste incineration.
Halogen is the main agent used in flame retardants and has been used for a long time.
However, for the reasons described above, filters that cause dioxins at the time of waste incineration cannot be used and a flame retardant for dehalogenation has been desired.

Japanese Patent Laid-Open No. 11-046965 JP 2000-287819 A

The present invention will be regulated in the future in various fields such as daily necessities, industrial materials, building materials, civil engineering materials, etc., in order to meet the current situation where the influence on the air quality of the environment has to be considered. An object of the present invention is to provide a long-fiber non-woven material that can be used for applications that meet the environmental standards of formaldehyde and that is low in formaldehyde emission to the air in the environment and that is particularly suitable for filter fabrics for air conditioning.
Another object of the present invention is to provide a filter using a non-halogen flame retardant that has a low environmental impact and does not use halogens to make the filter flame retardant.

That is, the present invention employs the following configuration.
1. The air permeability is 200 cc / sec / cm ² or more, the bending resistance by the Gurley method is 5.0 mN or more, the flame retardant content is 1 to 10% by mass, and the amount of formaldehyde released is 0.50 μg / 500 cm ^2. The filter base fabric is as follows.
2. 2. The filter substrate according to 1 above, wherein the filter base fabric is composed of a synthetic resin filament and a binder for fixing the filaments to each other, the synthetic resin filament has a fineness of 1.5 to 30 dtex and a binder content of 10 to 30% by mass. Filter base fabric.
3. Basis weight filter base fabric according to the above 1 or 2 which is 50 to 100 g / ^{m 2.}
4). The filter base fabric according to any one of the above 1 to 3, wherein the binder used is a polyester resin.
5. 5. The filter base fabric according to any one of 1 to 4 above, wherein the content of phosphorus atoms contained in the binder is 100 to 50000 ppm.
6). 6. The filter base fabric according to any one of the above 1 to 5, wherein the flame retardant contained in the binder is a phosphorus nitrogen flame retardant.

  According to the present invention, it is possible to provide a filter base fabric having a low amount of formaldehyde released to the environment and excellent in flame retardancy, and this base fabric is particularly suitable for a filter base fabric for air conditioning.

The filter base fabric in the present invention is preferably a long-fiber non-woven fabric. The long-fiber non-woven fabric is a long-fiber non-woven fabric obtained by a conventionally known production method such as a spunbond method, and is mainly composed of melt-spun filaments from a spinneret having a large number of nozzle holes.
As the synthetic resin forming the filament in the present invention, known synthetic fiber materials such as polyester, nylon, and polypropylene can be used. From the viewpoint of easiness of recycling and heat resistance, polyethylene terephthalate and polybutylene terephthalate are used. Common polyesters such as homopolyesters such as the above and known copolymerized polyesters having copolymer components in addition to these components are preferred.
These synthetic resin materials may contain stabilizers, ultraviolet absorbers, hygroscopic agents, lubricants, pigments, etc., but it is not preferable to have a formaldehyde source in them.

The air permeability of the filter base fabric is preferably 200 cc / sec / cm ² or more. An air permeability of 200 cc / sec · cm ² or less is not preferable because the filter pressure loss is increased and the life is shortened. More preferably, it is 250 cc / sec · cm ² or more, and further preferably 300 cc / sec · cm ² or more. The upper limit of the air permeability is not particularly limited, but is usually 1000 cc / sec · cm ² or less in many cases.

  The bending resistance of the filter base fabric by the Gurley method is 5.0 mN or more in length. When the length is less than 5.0 mN, the pleatability of the filter material bonded with the filter medium deteriorates, which is not preferable. Further, it is not preferable because the filter medium breaks in the dust-held state. Preferably it is 5.0 mN or more in length, More preferably, it is 6.0 mN or more in length. The upper limit of the bending resistance is not particularly limited, but is usually 10 mN or less in many cases.

  The flame retardant content of the filter base fabric is preferably 1 to 10% by mass. If it is less than 1% by mass, the flame retardancy is lowered, and it is not preferable because it cannot pass the flame retardancy standard as a filter of the final product. On the other hand, if it exceeds 10% by mass, the bleed phenomenon of the components in the flame retardant may occur, which adversely affects the filter-side equipment and the like. Preferably it is 3-10 mass%, More preferably, it is 5-10 mass%.

  The fineness of the synthetic resin filament constituting the filter base fabric is preferably 1.5 to 30.0 dtex. When the fineness is less than 1.5 dtex, thread breakage is caused during the production of the base fabric, which causes deterioration in operability. Moreover, since the rigidity of the filter base fabric is lowered and the filter after the filter medium is pasted together cannot be pleated, it is not preferable. Furthermore, the air permeability is lowered and the filter life is shortened, which is not preferable. On the other hand, if the fineness is larger than 30.0 dtex, the adhesiveness to the filter medium is lowered and a peeling phenomenon from the base fabric occurs, which is not preferable. Further, the entanglement of the fibers and the contact point are reduced and the strength is lowered, which is not preferable.

The spun synthetic resin filament is collected by a conveyor net or the like to form a web, and the web filament is heated by an embossing calender, etc. if necessary, entanglement treatment by needle punching, binder resin treatment, etc. These are joined by various joining means.
The basis weight of the sheet before the binder treatment is 40 to 90 g / m ² , preferably 60 to 80 g / m ² . When the basis weight of the sheet is less than 40 g / m ² , the rigidity as the filter base fabric is lowered, and the pleatability of the filter after the filter medium is bonded is not preferable. On the other hand, if it exceeds 90 g / m ² , the filter pressure loss is increased and the filter life is shortened.

For the binder treatment, a method such as spraying, dipping, or coating the binder resin can be selected as appropriate, but the pad / nip method is preferred in which the embossed calendar treatment or needle punched web is dipped in the binder resin treatment bath and then squeezed. .
The binder resin is preferably an acrylic resin water-based emulsion that does not become a VOC generation source such as formalin or an organic solvent. An auxiliary agent such as a catalyst, a pH adjusting agent, a penetrating agent, an antifoaming agent, and a dispersing agent can be used in combination with the emulsion type resin, but those that do not become a source of formaldehyde are preferable.
In view of the synergistic effect with the phosphorus-based flame retardant, it is more preferable to use a polyester resin aqueous emulsion.

After the binder resin liquid is applied, it is usually dried at a temperature of about 80 to 130 ° C. and then subjected to a baking treatment at 130 to 200 ° C. for 1 to 10 minutes, preferably at 150 to 180 ° C. for 1 to 5 minutes. By performing the baking process, VOC can be significantly reduced.
The solid content imparting amount of the binder resin is 3 to 30% by mass, preferably 5 to 15% by mass with respect to the total mass of the base fabric. When the amount of the solid content of the binder resin is less than 3% by mass, the rigidity of the product is insufficient, and when it exceeds 30% by mass, the pressure loss of the filter is increased due to plugging between the fibers and the life is shortened. Therefore, it is not preferable.

  After processing the binder resin, heat and pressure from a calender roller or the like can be further applied to make the fixing between the filaments stronger, smooth the binder resin on the sheet surface, or give an emboss pattern.

The basis weight as a filter base fabric is preferably 50 to 100 g / m ² . When the basis weight of the filter base fabric is less than 50 g / m ² , the rigidity is lowered and the pleatability of the filter after the filter medium is bonded is not preferable. On the other hand, if it exceeds 100 g / m ² , the filter pressure loss is increased and the filter life is shortened, which is not preferable.

The amount of formaldehyde released from the filter base fabric is preferably 0.50 μg / 500 cm ² or less.
The amount of formaldehyde released in the present invention is measured by the following method.
This is the amount of formaldehyde released into 12 liters of nitrogen gas from a base fabric having an area of 500 cm ² in a nitrogen gas flow atmosphere at a temperature of 70 ° C. with an air flow rate of 12 liters per hour. In other words, it measures the amount of formaldehyde generated from a certain area, not to a certain mass of the sample to be measured, and influence of indoor air pollution from specific areas of walls, floors, ceilings, and other articles facing the use space. It is evaluated in the form that is as close as possible to the actual usage situation of the user who receives it.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
<Formaldehyde generation amount>
Take 5 cm x 10 cm x 10 pieces of base fabric in a collection container.
High-purity nitrogen gas was introduced at a rate of 0.2 ml / min at a temperature of 70 ° C. in the collection container, and passed through a commercially available DNPH (2,4-dinitrophenylhydrazine) cartridge for 12 liters for 1 hour, and the generated formaldehyde was DNPH derivatized. Adsorb on solid phase. The formaldehyde DNPH derivative is extracted from the cartridge with 5 ml of acetonitrile to prepare a sample solution.
The sample solution is introduced into a high performance liquid chromatograph (HPLC) Hewlett-Packard HP1100 and analyzed.
Other HPLC analysis conditions were as follows: Column: μBondapak C18 10 μm 125Å 3.9 mm × 150 mm manufactured by Waters, mobile phase: water / acetonitrile = 45/55, flow rate = 0.8 ml / min, detection: UV 360 nm.
From the above, the amount of formaldehyde released into 12 liters of nitrogen gas from a base fabric having an area of 500 cm ² in a nitrogen gas flow atmosphere at a temperature of 70 ° C. with an air flow rate of 12 liters per hour is determined.
<Fragile air permeability>
According to JIS L-1096.
<Bending softness (Gurley type)>
According to JIS L-1096.
<Flame retardant performance>
Filter media combustion test for air purifier (JACA NO11A)
Class 3 standard ・ After 4 flames out of 5 test pieces 2 s or less ・ After flame time of all specimens 10 s or less ・ All specimens are melted and dropped, and the specimens are 175 ± 25 mm Do not ignite the labeling cotton placed underneath. • Remaining time of all test pieces is 30 s or less. Pass: Those that satisfy all the above conditions. Fail: Those that do not satisfy all of the above conditions <Pleated performance>
Pleating was performed at a pitch of 5 cm using a reciprocating pleating machine.
Pass: Form regular pleats Fail: Unable to form pleats <bleed out>
No problem: Almost no bleed out Problem present: A bleed out occurs and a phenomenon such as deliquescence occurs.
<Adhesiveness with filter media>
After adhering a filter medium such as melt blown nonwoven fabric (hereinafter referred to as MB) and a base material by a laminating method such as powder lamination or curtain spray method, as a guideline for judging whether the adhesion is appropriate or not, MB material destruction when peeled There is a standard of whether or not this happens more than half. If this is passed, it can be judged that there is durability when used as a pleating process or an actual unit.
Pass: MB breaks more than half when peeled Fail: MB doesn't break more than 1/3 when peeled

[Example 1]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 4.4 dtex by the spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. Pads and nips were dried in a mixed liquid in which a flame retardant was mixed (solid content ratio 80/20), dried, and baked to obtain a base fabric having a basis weight of 71 g / m ² and an applied amount of binder component of 25% by mass. As a result of measuring the amount of formaldehyde generated from this base fabric by the method described above, the amount of formaldehyde generated was 0.1 μg / 500 cm ² . The Gurley type bending resistance was 5.1 mN.

[Example 2]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 2.2 dtex by the spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. After padding the blended liquid (70/30 solid content ratio) with a flame retardant and immobilizing it with a pad, nip, and baking method, it is further heated with a calender roller (205 ° C) and a binder with a basis weight of 93 g / m ² A base fabric having a component application amount of 25% was obtained.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.30 μg / 500 cm ² . The Gurley type bending resistance was 7.1 mN.

[Example 3]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 30 dtex by the spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. and a phosphorus nitrogen flame retardant are added. After the mixed liquid (solid content ratio 70/30) is padded and fixed by the pad nip baking method, it is further heated with a calender roller (205 ° C.), and the weight of the binder component is 71 g / m ² . A base fabric having an applied amount of 25% was obtained.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.30 μg / 500 cm ² . The Gurley type bending resistance was 5.1 mN.

[Example 4]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 11 dtex by a spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. and a phosphorus nitrogen flame retardant are added. After the mixed liquid (solid content ratio 70/30) is padded and fixed by the pad nip baking method, it is further heated with a calender roller (205 ° C.), and the weight of the binder component is 71 g / m ² . A base fabric having an applied amount of 10% was obtained.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.10 μg / 500 cm ² . The Gurley bending resistance was 5.2 mN.

[Comparative Example 1]
As a result of processing in the same manner as in Example 1 except that the polyethylene terephthalate was melt-spun and the web was formed with a filament having a single yarn fineness of 1.1 dtex by the spunbond method, the amount of the binder component applied was 83 g / m ^2. A 25% base fabric was obtained.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.30 μg / 500 cm ² . The Gurley type bending resistance was 4.5 mN.

[Comparative Example 2]
Polyethylene terephthalate is melt-spun, a web is formed with filaments having a single yarn fineness of 4.4 dtex by the spunbond method, needle punching is performed, acrylic resin having general crosslinking reactivity, and melamine resin as a crosslinking agent Then, after fixing by a pad nip baking method in the same manner as in Example 1 with a preparation solution comprising a tertiary amine as a catalyst, a base fabric having a basis weight of 71 g / m ² and a binder component application amount of 22% is obtained. It was.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 9.17 μg / 500 cm ² . The Gurley bending resistance was 6.5 mN.

[Comparative Example 3]
Processing was carried out in the same manner as in Example 1 except that polyethylene terephthalate was melt-spun and a web was formed with a filament having a single yarn fineness of 40 dtex by the spunbond method. As a result, the weight of the binder component was 25% at a basis weight of 71 g / m ^2. A base fabric was obtained.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.20 μg / 500 cm ² . The Gurley type bending resistance was 7.1 mN.

[Comparative Example 4]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 4.4 dtex by the spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. As a result of processing in the same manner as in Example 1 except that the preparation liquid mixed with the fuel (solid content ratio 94/6) was padded, a base fabric having a basis weight of 71 g / m ² and a binder component application amount of 25% was obtained. .
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.10 μg / 500 cm ² . The Gurley type bending resistance was 5.1 mN.

[Comparative Example 5]
As a result of processing in the same manner as in Example 1 except that a polyethylene terephthalate was melt-spun and a web was formed with a filament having a single yarn fineness of 4.4 dtex by the spunbond method, the amount of binder component applied was 40 g / m ² per unit area. A 25% base fabric was obtained.
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.10 μg / 500 cm ² . The Gurley type bending resistance was 3.5 mN.

[Comparative Example 6]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 4.4 dtex by the spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. As a result of processing in the same manner as in Example 1 except that the preparation liquid mixed with the flame retardant (solid content ratio 60/40) was padded, a base fabric having a basis weight of 71 g / m ² and a binder component application amount of 25% was obtained. .
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.10 μg / 500 cm ² . The Gurley type bending resistance was 5.1 mN.

[Comparative Example 7]
Polyethylene terephthalate is melt-spun, a web is formed with a filament having a single yarn fineness of 4.4 dtex by the spunbond method, needle punching is performed, and then polyester resin ES-7 manufactured by Nikka Chemical Co., Ltd. As a result of processing in the same manner as in Example 1 except that the preparation liquid mixed with the fuel (solid content ratio 20/80) was padded, a base fabric having a basis weight of 71 g / m ² and a binder component application amount of 5% was obtained. .
As a result of measuring the formaldehyde generation amount of this base fabric by the method described above, the formaldehyde generation amount was 0.10 μg / 500 cm ² . The Gurley type bending resistance was 3.5 mN.

  The characteristics of the base fabric obtained in the examples are summarized in Table 1.

  According to the present invention, it is possible to provide a filter base fabric having a low amount of formaldehyde released to the environment and excellent in flame retardancy, and this base fabric is particularly suitable for a filter base fabric for air conditioning.

Claims (6)

The air permeability is 200 cc / sec / cm ² or more, the bending resistance by the Gurley method is 5.0 mN or more, the flame retardant content is 1 to 10% by mass, and the amount of formaldehyde released is 0.50 μg / 500 cm ^2. The filter base fabric is as follows.   The filter base fabric is composed of a synthetic resin filament and a binder for fixing the filaments to each other, the fineness of the synthetic resin filament is 1.5 to 30 dtex, and the binder content is 10 to 30% by mass. The filter base fabric described. Filter base fabric according to claim 1 or 2 basis weight is 50 to 100 g / ^{m 2.}   The filter base fabric according to any one of claims 1 to 3, wherein the binder used is a polyester resin.   The filter base fabric according to any one of claims 1 to 4, wherein the content of phosphorus atoms contained in the binder is 100 to 50,000 ppm. The base fabric for a filter according to any one of claims 1 to 5, wherein the flame retardant contained in the binder is a phosphorus nitrogen flame retardant.