JP6571564B2 - Air filter media - Google Patents

Description

  The present invention relates to an air filter medium having aldehyde adsorption performance.

  In recent years, from the influence of infectious diseases caused by viruses such as influenza, such as dust from the deserts and dry areas in the inland of East Asia (yellow sand), pollen of PM2.5, cedar, cypress, etc. There are many living environments in which indoor air is purified, temperature-controlled, and humidity-controlled using air purifiers and air conditioners instead of ventilation of indoor air with windows open. In particular, there is a strong market demand for functions for improving the comfort of spaces such as homes, workplaces, and automobiles. Air purifiers are becoming more widespread, and various high-performance air filter media that are attached to air purifiers are used. It is requested to be

  Lower aldehydes such as formaldehyde and acetaldehyde generated from indoor furniture, automobile interiors, cigarette smoke, etc. are harmful gases with an irritating odor. Formaldehyde and acetaldehyde are suspected to be carcinogenic, and are classified as causative substances of sick house syndrome, and are classified into 13 kinds of volatile organic compounds (VOC) determined by the Ministry of Health, Labor and Welfare.

  From these backgrounds, there is an increasing need for an air filter medium having an aldehyde adsorption performance in order to quickly reduce the aldehyde gas concentration in a room or vehicle and protect the health of people and pets.

  Furthermore, the user's awareness of energy saving has been increasing more than ever, and there is a constant demand for reducing the pressure loss of the air filter media.

  For example, in order to improve the VOC adsorption performance, a filter medium (for example, Patent Document 1) in which particles having an average particle diameter of 1 μm or less are supported on a nonwoven fabric at a specific binder ratio is disclosed, but the effect is still insufficient. I can not say.

JP 2015-157250 A

  An object of the present invention is to provide an air filter medium having excellent aldehyde adsorption performance and low pressure loss.

  As a result of the study by the present inventors, in an air filter medium including a breathable base material, an adsorbent, and a binder, the aldehyde adsorption performance can be controlled by the type of the binder, and the adsorbent has an average particle size on the order of micrometers. It has been found that by having porous particles, it exhibits better aldehyde adsorption performance.

That is, the present invention
(1) In an air filter medium including a breathable base material, an adsorbent and a binder,
The adsorbent is porous particles having an average particle diameter of 1 to 50 μm, and the binder is at least one binder selected from the group consisting of styrene-acrylic resins, vinyl chloride-acrylic resins, and silicone resins. Ri, the binder is a emulsion binder, the average particle diameter of 50nm or more and less than 200 nm, air filter medium content of the binder for the adsorbent is characterized by 5-60% by mass Rukoto,
(2) The air filter medium according to (1), wherein the binder is a styrene-acrylic resin ,
It is.

  According to the present invention, an air filter medium excellent in aldehyde adsorption performance and low pressure loss can be provided.

  Hereinafter, the air filter medium of the present invention will be described in detail. The air filter medium of the present invention includes a breathable base material, an adsorbent and a binder, the adsorbent is porous particles having an average particle diameter of 1 to 50 μm, and the binder is a styrene-acrylic resin, vinyl chloride-acrylic. It is at least 1 sort (s) of binders chosen from the group which consists of a system resin and a silicone system resin, It is characterized by the above-mentioned.

  In the present invention, the porous particles as the adsorbent include activated carbon, natural and synthetic zeolite, activated alumina, activated clay, sepiolite, iron-based compounds such as iron oxide, zinc oxide, magnesium oxide, aluminum silicate, silica, silica -Zinc oxide composite, silica-alumina-zinc oxide composite, composite phyllosilicate, etc., or a mixture thereof. More preferably, these porous particles are modified with an amino compound.

  The average particle diameter of the porous particles in the present invention will be described. The average particle diameter of the porous particles is 1 to 50 μm, and more preferably 3 to 20 μm. When the average particle diameter of the porous particles is less than 1 μm, the porous particles in the coating liquid are likely to aggregate, so that the solid content in the coating varies, and the porous particles easily fall off from the filter medium. Aldehyde adsorption performance is not fully expressed. By increasing the binder content, it is possible to suppress the removal of the porous particles from the filter medium, but the gap between the fibers constituting the filter medium is reduced, the air permeability of the filter medium is deteriorated, and the porous particles The surface is excessively coated with the binder, and the aldehyde adsorption performance is not sufficiently developed. When the average particle diameter of the porous particles is larger than 50 μm, the adhesion area with the fibers constituting the filter medium decreases, so that the porous particles easily fall off from the filter medium, and the aldehyde adsorption performance is not sufficiently exhibited.

  In the present invention, the binder is at least one binder selected from the group consisting of styrene-acrylic resins, vinyl chloride-acrylic resins, and silicone resins, and one or more of these binders are selected. Can be used. In order to achieve both higher aldehyde adsorption performance and lower pressure loss, a styrene-acrylic resin is preferable.

The binder is preferably an emulsion binder. Although the average particle diameter of an emulsion binder is not specifically limited, It is preferable that it is 50-500 nm, and it is more preferable that it is 100-200 nm. This is because when the average particle size of the emulsion binder is 50 to 500 nm, the solid content adhesion amount in coating is more stable. In the present invention, the average particle size of the emulsion binder is 50 nm or more and less than 200 nm.

  In the present invention, the average particle diameter refers to a median diameter (d50) measured using a particle size distribution measuring apparatus by a laser diffraction / scattering method.

  Although content of a binder is not specifically limited, It is preferable that it is 5-60 mass% on the solid content mass basis with respect to adsorption agent. This is because when the binder content is 5 to 60% by mass, the solid content adhesion amount in the coating is stabilized, and higher aldehyde adsorption performance and lower pressure loss can be achieved at the same time.

  The material of the breathable substrate used in the filter medium of the present invention includes polyamide fibers, polyester fibers, polyalkylene paraoxybenzoate fibers, polyurethane fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers. Fiber, synthetic fiber such as polyacrylonitrile fiber, polyolefin fiber, phenol fiber, inorganic fiber such as glass fiber, metal fiber, alumina fiber, carbon fiber, activated carbon fiber, wood pulp, bamboo pulp, hemp pulp, kenaf pulp, From raw materials such as straw pulp, bagasse pulp, cotton linter pulp, natural fibers such as cotton, wool, silk, recycled cellulose fibers such as recycled paper and rayon, proteins such as collagen, alginic acid, chitin, chitosan, starch and other polysaccharides Recycled fiber, etc., or these fibers The fibers imparted with functions such as hydrophilicity and flame retardancy alone or in combination may be used.

  There are no particular restrictions on the method for producing the breathable substrate used in the filter medium of the present invention, and depending on the purpose and application, a dry method, a wet papermaking method, a melt blown method, a spunbond method, a flash spinning method, an airlaid method, a static method. Strength of web obtained by electrospinning method, etc. is developed by hydroentanglement method, needle punch method, physical method such as stitch bond method, thermal bond method such as thermal bond method, and adhesive method such as resin bond Can be produced by appropriately combining the methods.

Although the basic weight of the air permeable base material used for the filter medium of this invention is not specifically limited, It is preferable that it is 30-150 g / m < ² >. If the basis weight of the breathable substrate is less than 30 g / m ² , the adsorbent may not be sufficiently supported, and the aldehyde adsorption performance may become too small. If the basis weight of the breathable substrate exceeds 150 g / m ² , the pressure loss may become too high.

  The air filter medium of the present invention is produced by a method in which an adsorbent is supported on a gas-permeable base material with a binder. The method for supporting the adsorbent is not particularly limited as long as the adsorbent can be adhered to the breathable substrate as uniformly as possible. Dispersion containing adsorbent and binder as coating liquid, on air permeable substrate, screen printing method, roll coating method, spray method, dipping method, curtain coating method, bar coating method, air knife method, hot melt method, gravure Examples thereof include a method in which a breathable substrate is applied by a coating method such as a coating method, a brush coating method, or an offset printing method, and a solvent or a dispersion medium is removed and supported by drying or the like.

In this invention, it is preferable that the solid content adhesion amount of an adsorbent is 3-25 g / m < ² > with respect to a base material. When the solid content adhesion amount of the adsorbent is less than 3 g / m ² , the aldehyde adsorption performance may become too small. If it exceeds 25 g / m ² , the aldehyde adsorption performance is sufficient, but may not be economically met. A more preferable solid content adhesion amount is 5 to 20 g / m ² .

  In addition, if necessary, for the purpose of adding other performance without departing from the spirit of the present invention, deodorization, antibacterial, antifungal, antiviral, insecticidal, insecticidal, deodorizing, aroma, temperature sensing, heat retention, storage Temperature, heat storage, heat generation, heat absorption, waterproofing, water resistance, water repellency, hydrophobicity, hydrophilicity, dehumidification, humidity adjustment, moisture absorption, oil repellency, lipophilic, oil absorption, transpiration or sustained release of water and volatile chemicals, etc. These functions can be added to the air filter medium.

  The air filter medium of the present invention is mounted and used in an air treatment device by forced supply / exhaust by a machine such as an air conditioner, an air purifier, a vacuum cleaner, a dehumidifier, a dryer, a humidifier, a ventilator, a fan, or a heat exchanger. Thus, a favorable effect can be obtained for adsorption of aldehyde gas in the space. Alternatively, the air filter medium of the present invention may be used for an external air flow inlet (such as a vent or a window) for natural supply and exhaust.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the examples. In the examples, “%” and “part” represent “% by mass” and “part by mass”, respectively, unless otherwise specified. Examples 4, 6, 7, 9-12 and 15 are reference examples.

(Average particle size)
The average particle size of the porous particles and the average particle size of the emulsion binder were measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., trade name: Microtrac (registered trademark) MT3300 type). d50) was measured. The unit of the average particle diameter of the porous particles is μm, and the unit of the average particle diameter of the emulsion binder is nm.

Example 1
A polyester spunbonded nonwoven fabric (basis weight 50 g / m ² ) is used as a breathable substrate, an aluminum silicate modified with an amino compound having an average particle size of 1 μm as porous particles as an adsorbent, and an average particle size of 150 nm as a binder. The coating liquid formed by dispersing the styrene-acrylic resin emulsion binder in water and mixing and stirring is applied to a breathable substrate by size press treatment and dried at 120 ° C. An air filter medium was prepared. In coating, the adsorbent solid content (target value) is 10 g / m ² , the binder solid content (target value) is 3 g / m ² , and the binder content to the adsorbent is 30. %Met.

(Example 2)
An air filter medium of Example 2 was produced in the same manner as Example 1 except that aluminum silicate modified with an amino compound having an average particle diameter of 10 μm was used as the porous particles.

(Example 3)
An air filter medium of Example 3 was produced in the same manner as in Example 1 except that aluminum silicate modified with an amino compound having an average particle diameter of 50 μm was used as the porous particles.

(Example 4)
An air filter medium of Example 4 was produced in the same manner as in Example 2 except that a silicone resin emulsion binder having an average particle diameter of 200 nm was used as the binder.

(Example 5)
An air filter medium of Example 5 was produced in the same manner as Example 2 except that a vinyl chloride-acrylic resin emulsion binder having an average particle diameter of 170 nm was used as the binder.

(Example 6)
An air filter medium of Example 6 was produced in the same manner as in Example 2 except that a styrene-acrylic resin emulsion binder having an average particle diameter of 30 nm was used as the binder.

(Example 7)
The air filter medium of Example 7 was produced in the same manner as Example 6 except that the solid content adhesion amount of the binder was 6 g / m ² and the binder content with respect to the adsorbent was 60%.

(Example 8)
An air filter medium of Example 8 was produced in the same manner as in Example 2 except that a vinyl chloride-acrylic resin emulsion binder having an average particle diameter of 50 nm was used as the binder.

Example 9
An air filter medium of Example 9 was produced in the same manner as in Example 2 except that a vinyl chloride-acrylic resin emulsion binder having an average particle diameter of 500 nm was used as the binder.

(Example 10)
An air filter medium of Example 10 was produced in the same manner as in Example 2 except that a vinyl chloride-acrylic resin emulsion binder having an average particle diameter of 600 nm was used as the binder.

(Example 11)
An air filter medium of Example 11 was produced in the same manner as Example 10 except that the solid content of the binder was 6 g / m ² and the binder content relative to the adsorbent was 60%.

(Example 12)
The air filter medium of Example 12 was produced in the same manner as Example 2 except that the solid content adhesion amount of the binder was 0.3 g / m ² and the binder content with respect to the adsorbent was 3%.

(Example 13)
An air filter medium of Example 13 was produced in the same manner as Example 2 except that the solid content of the binder was 0.5 g / m ² and the content of the binder with respect to the adsorbent was 5%.

(Example 14)
The air filter medium of Example 14 was produced in the same manner as in Example 2 except that the solid content adhesion amount of the binder was 6 g / m ² and the binder content with respect to the adsorbent was 60%.

(Example 15)
An air filter medium of Example 15 was produced in the same manner as in Example 2 except that the solid content of the binder was 7 g / m ² and the content of the emulsion binder with respect to the adsorbent was 70%.

(Comparative Example 1)
An air filter medium of Comparative Example 1 was produced in the same manner as in Example 2 except that aluminum silicate modified with an amino compound having an average particle size of 0.1 μm was used as the porous particles.

(Comparative Example 2)
An air filter medium of Comparative Example 2 was produced in the same manner as Comparative Example 1 except that the solid content of the binder was 6 g / m ² and the binder content relative to the adsorbent was 60%.

(Comparative Example 3)
The air filter medium of Comparative Example 3 was produced in the same manner as Comparative Example 1 except that the solid content of the binder was 0.5 g / m ² and the binder content with respect to the adsorbent was 5%.

(Comparative Example 4)
An air filter medium of Comparative Example 4 was produced in the same manner as Example 2 except that aluminum silicate modified with an amino compound having an average particle size of 80.0 μm was used as the porous particles.

(Comparative Example 5)
An air filter medium of Comparative Example 5 was produced in the same manner as Example 2 except that a urethane resin emulsion binder having an average particle size of 200 nm was used as the binder.

(Comparative Example 6)
The air filter medium of Comparative Example 6 was produced in the same manner as in Example 2 except that an ethylene-vinyl acetate resin emulsion binder having an average particle diameter of 600 nm was used as the binder.

(Comparative Example 7)
An air filter medium of Comparative Example 7 was produced in the same manner as Example 2 except that no adsorbent was contained. The solid content of the binder is 3 g / m ² , that is, the same amount as in Example 2.

(Comparative Example 8)
An air filter medium of Comparative Example 8 was produced in the same manner as Example 2 except that no binder was contained.

  The air filter media of Examples 1 to 15 and Comparative Examples 1 to 8 produced as described above were evaluated by the following evaluation method. In addition, about each evaluation, when there was no description of temperature and humidity, all were performed in the environment of 25 degreeC and 50% RH (relative humidity).

(Variation in solid content in coating)
By carrying out the steps of producing the air filter media of Examples 1 to 15 and Comparative Examples 1 to 8 30 times, for each filter media, calculating the solid content adhesion amount in coating, and obtaining the standard deviation σ, The variation in the solid content was evaluated. The unit of the solid content is g / m ² . The standard deviation σ is “偏差: less than 1”, “◯: 1 or more and less than 2”, and “×: 2 or more”. It can be said that it is preferable that ◎ is excellent, since there is little unevenness in the coating process, and thus good deodorization performance can be expressed.

(Adsorbent removal)
The filter media obtained in Examples 1 to 15 and Comparative Examples 1 to 6 and 8 were each cut into a size of 10 cm × 10 cm to obtain specimens, which were individually evaluated. On the experimental bench, a specimen was placed on A4 size black drawing paper, 200 g of weight was dropped vertically three times from a height of 5 cm above the specimen, and the amount of adsorbent dropped on the black drawing paper was visually evaluated. In the present invention, ◎ and ○ are the subject of the present invention, assuming that the adsorbent is “◎: not dropped”, “◯: dropped slightly”, and “×: dropped much”. Preferably, it is said that it has better aldehyde adsorption performance because the adsorbent does not fall off from the filter medium.

(Acetaldehyde adsorption performance test)
The filter media obtained in Examples 1 to 15 and Comparative Examples 1 to 8 were each cut into a size of 10 cm × 10 cm to obtain specimens and individually tested. The specimen was put in a 5-liter odor bag and sealed, 10 ppm of acetaldehyde gas was injected, and the concentration of acetaldehyde in the odor bag 30 minutes later was measured with a gas detector tube. The acetaldehyde concentration in the odor bag after 30 minutes was evaluated in three stages as “◎: less than 1 ppm”, “◯: 1 ppm or more and less than 2 ppm”, and “×: 2 ppm or more”. In the present invention, ◎ and ○ are the subject of the invention. It can be said that the life of the filter medium is long because more acetaldehyde gas is adsorbed when it is preferably ◎.

(Evaluation of pressure loss)
According to JIS B 9908, the pressure loss of the filter media obtained in Examples 1 to 15 and Comparative Examples 1 to 8 was measured at a wind speed of 5.3 cm / second. The pressure loss was evaluated in three stages as “◎: less than 6 Pa”, “◯: from 6 Pa to less than 12 Pa”, and “×: 12 Pa or more”. In the present invention, ◎ and ○ are the subject of the invention. It can be said that it is preferably ◎ that has better air permeability.

  Table 1 shows configurations of Examples 1 to 15 and Comparative Examples 1 to 8.

  Table 2 shows the evaluation results of Examples 1 to 15 and Comparative Examples 1 to 8.

  As is apparent from the results in Table 2, the adsorbent is porous particles having an average particle diameter of 1 to 50 μm, and the binder is selected from the group consisting of styrene-acrylic resin, vinyl chloride-acrylic resin, and silicone resin. In the air filter medium of Examples 1 to 15, which is at least one binder selected, the dispersion of the solid content amount in coating is small, the adsorbent can be prevented from falling off, and good aldehyde adsorption performance is expressed. It can be seen that the pressure loss is low.

  On the other hand, in the air filter media of Comparative Examples 1 to 3 in which the average particle diameter of the porous particles as the adsorbent is less than 1 μm, the dispersion of the solid content adhesion amount in coating is large, and the acetaldehyde adsorption performance is low. Recognize. It can be seen that in the air filter medium of Comparative Example 4 in which the average particle diameter of the porous particles as the adsorbent is more than 50 μm, the adsorbent falls off and the acetaldehyde adsorption performance is low. It can be seen that the air filter medium of Comparative Example 5 in which the binder is a urethane resin has low acetaldehyde adsorption performance. It can be seen that the air filter medium of Comparative Example 6 in which the binder is an ethylene-vinyl acetate resin has a large variation in the amount of solid content in coating, the adsorbent falls off, and the acetaldehyde adsorption performance is low. In the air filter medium of Comparative Example 7 containing no adsorbent, the acetaldehyde adsorption performance is low, and in the air filter medium of Comparative Example 8 containing no binder, there is a large variation in the amount of solids adhering to the coating. It can be seen that the agent dropped out and the acetaldehyde adsorption performance was low.

  From the results of Examples 2, 4 and 5, the air filter medium of Example 2 in which the binder is a styrene-acrylic resin is better than the air filter medium of Example 5 in which the binder is a vinyl chloride-acrylic resin. It can be seen that the pressure loss is low. Moreover, it turns out that the air filter medium of Example 2 whose binder is styrene-acrylic resin expresses better acetaldehyde adsorption performance than the air filter medium of Example 4 whose binder is silicone resin. .

  From the results of Examples 5 and 8 to 10, the average particle diameter of the emulsion binder is 50 to 500 nm as compared with the air filter medium of Example 10 in which the average particle diameter of the emulsion binder exceeds 500 nm. It can be seen that the air filter media of Nos. 8, 8 and 9 exhibit better acetaldehyde adsorption performance because the adsorbent is less likely to fall off.

  From the results of Examples 2 and 6, the air filter of Example 2 in which the average particle diameter of the emulsion binder is 50 to 500 nm as compared with the air filter medium of Example 6 in which the average particle diameter of the emulsion binder is less than 50 nm. It can be seen that the filter medium has a smaller variation in the amount of solid content in the coating and exhibits better acetaldehyde adsorption performance.

  From the result of Examples 12-15, compared with the air filter medium of Example 12 whose content of the binder with respect to an adsorbent is less than 5 mass%, the content of the binder with respect to an adsorbent is 5 mass%. It can be seen that the air filter medium of 13 has a smaller variation in the solid content adhesion amount during coating. Further, the air filter medium of Example 14 in which the binder content relative to the adsorbent is 60% by mass as compared with the air filter medium of Example 15 in which the binder content relative to the adsorbent exceeds 60% by mass. However, it can be seen that there is little variation in the amount of solid content in the coating, and good aldehyde adsorption performance is exhibited.

  The filter medium for an air filter of the present invention can be used for an air filter used for an air conditioner or an air cleaner used in buildings, factories, automobiles, general households and the like.

Claims (2)

In an air filter medium containing a breathable base material, an adsorbent and a binder,
The adsorbent is porous particles having an average particle diameter of 1 to 50 μm, and the binder is at least one binder selected from the group consisting of styrene-acrylic resins, vinyl chloride-acrylic resins, and silicone resins. Ri, the binder is a emulsion binder, the average particle diameter of 50nm or more and less than 200 nm, air filter medium content of the binder for the adsorbent is characterized by 5-60% by mass Rukoto.   The air filter medium according to claim 1, wherein the binder is a styrene-acrylic resin.