WO2021112124A1

WO2021112124A1 - Hot-melt adhesive and filter assembled using said adhesive

Info

Publication number: WO2021112124A1
Application number: PCT/JP2020/044853
Authority: WO
Inventors: 昌宏須藤
Original assignee: 東亞合成株式会社
Priority date: 2019-12-04
Filing date: 2020-12-02
Publication date: 2021-06-10
Also published as: CN114761512B; CN114761512A; JPWO2021112124A1

Abstract

This adhesive is a hot-melt adhesive satisfying the following conditions (A), (B), and (C). (A) Conformance to ASTM D3236-73, and the melting viscosity measured at 190℃ using a No. SC4-27 spindle is 1,000-15,000 mPa·s. (B) Conformance to JIS K6863-1994, and the softening point measured using silicone oil as a heat medium is 130-170℃. (C) Conformance to JIS K7196-1991, and when a cylindrical detection rod with a diameter of 3 mm is set on a specimen cut out in a 5-mm square from a sample sheet molded at a thickness of 2 mm, nitrogen gas is flowed over the specimen at a rate of 100 ml/min, a load of 10 gf is applied to the specimen, and the temperature of the specimen is ramped up at a speed of 5℃/min, the specimen softens and displacement thereof in the contraction direction reaches 0.05 mm at a temperature of at least 90℃.

Description

Hot melt adhesive and filter assembled with the adhesive

The present invention relates to a filter assembly adhesive, particularly a hot melt adhesive used in an air filter produced by pleating a filter medium.
The air filter assembled according to the present invention is particularly used for purifying air for the interior of an automobile.

It is known that dust and the like are removed by passing air and other fluids through a filter created by pleating a filter medium such as a non-woven fabric. The reason for folds the filter medium is to make the area of the filter as large as possible for the passing fluid, and for this purpose, it is preferable that the folds are higher and the number of folds is larger. However, when the height of the folds and the number of folds are increased, the folds are deformed by the pressure of the passing fluid, and the folds easily come into contact with each other. The contact of the folds reduces the filtration area of the filter, reduces the air permeability, and causes a large pressure loss, which causes a deterioration in the filter performance. Therefore, it is necessary to prevent contact with the folds.

In order to prevent contact of the folds, a method is proposed to prevent contact of the tops of adjacent folds by applying hot melt adhesive linearly to the tops of the folds in a direction crossing the direction in which the folds extend and solidifying them. (Hereinafter, also referred to as "top adhesive").
The following various improvement methods have been proposed for the top bonding. For example, in order to keep the folds in order and to obtain a filter that does not easily lose its shape, effervescent resin is used as a hot melt adhesive to give flexibility to the adhesion between the pleated filter media folds. A method of having the adhesive is disclosed (Patent Document 1). Furthermore, for example, there is disclosed an adhesion prevention member made of a hot melt adhesive whose surface layer has a lower crystallinity than the inside, which can surely prevent the adhesion of folds and prevent the surface layer from falling off due to vibration or the like (Patent Document 2). ..

As described above, the hot melt adhesive plays an extremely important role in the method of preventing the contact of the folds of the pleated filter medium, and the composition thereof is an ethylene / vinyl acetate (EVA) adhesive. It was a polyethylene-based, polypropylene-based, polyethylene / polypropylene-based or polyester-based adhesive. Polypropylene, which has poor adhesiveness, is sometimes used as the filter medium for the filter. However, since this filter medium is a non-woven fabric and is porous, even polyester or polyamide adhesives, which are normally difficult to adhere to polypropylene, can be adhered by the anchoring effect. It becomes possible.

However, since the hot melt adhesives having these compositions have low flexibility, it is difficult to perform the predetermined processing with the hot melt adhesives. If the flexibility is increased, the filter tends to lose its shape at a higher normal environmental temperature (-20 to 80 ° C). Therefore, in order to prevent the filter from losing its shape at such a temperature, hot melt adhesive with a high softening point is adhered. The agent will be adopted.
In this case, if the coating temperature is low, the viscosity increases, so that there is a problem that the coating temperature rises. For example, when a hot melt adhesive is applied at a coating temperature of 180 ° C. or higher in order to obtain a low viscosity that can be applied in an industrial production process, when the filter medium of the filter is polypropylene, the coating temperature is 180 ° C. , Polypropylene, which is a filter medium, may be deformed. If the coating temperature is lowered to avoid deformation of the polypropylene of the filter medium, the viscosity of the hot melt adhesive becomes too high, and stable coating of the hot melt adhesive cannot be performed.
As a hot melt adhesive that solves such a problem, a hot melt adhesive containing a copolymer of 1-butene and another olefin, polypropylene wax, and a tackifier resin as constituents has been proposed (Patent Document 3). ..

Since the hot melt adhesive having this composition has a low melt viscosity and a small temperature dependence of the melt viscosity, the adhesive can be applied to the filter medium at a low coating temperature, and the filter medium which is sensitive to heat can also be coated. It was possible to prevent the folds from losing their shape even when the ambient temperature was high.
However, this hot melt adhesive has a limit in heat resistance, and when it is in a temperature environment of about 80 ° C. (hereinafter, also referred to as "high temperature environment") assuming the temperature of an automobile interior left outdoors, the hot melt adhesive is hot melted. There is a problem that the surface of the adhesive becomes sticky, and the hot melt adhesives applied between the folds stick to each other and the folds come into contact with each other even if a slight stress is applied to the filter.
In particular, when a base material with high repulsive force is used as the filter medium, the stress to flatten the original is strong even after folds, and when it exceeds the cohesive force of the solidified hot melt adhesive adhered to the top, hot melt adhesion is achieved. In some cases, the peeling of the agent was prolonged.

On the other hand, the pleated filter medium is used as a filter in a form of being fitted into a frame composed of end plates arranged around the filter medium, but in order to fix the filter medium inside the frame, the end face in the direction in which the folds of the filter extend, Further, if necessary, both side ends parallel to the direction in which the folds of the filter medium extend are bonded to the end plate of the frame (hereinafter, also referred to as "end bonding").

When performing both the end bonding process of bonding a pleated filter medium to the frame and the top bonding of linearly applying hot melt adhesive to the top of the folds to solidify the filter, Either step may be performed first.

As an adhesive for edge bonding, for example, an olefin-based or ethylene-vinyl acetate-based hot melt adhesive having a relatively low melting temperature has been proposed in order to prevent the filter medium from melting (Patent Document 4). However, in the case of edge bonding, it is difficult to obtain sufficient adhesive strength because the contact area between the filter medium and the end plate is small, and in the case of these hot melt adhesives, stress such as vibration is applied or peeling occurs in a high temperature environment. I had something to do. In particular, when a base material with high repulsive force is used as the filter medium, the stress to flatten the original is strong even after folding the folds, and when the cohesive force of the solidified hot melt adhesive bonded to the ends is exceeded, the surface of the folds In some cases, the peeling from the skin was increased.
A polyamide-based hot melt adhesive has been proposed for the purpose of improving the sealing property between the filter medium and the end plate of the frame and having excellent pressure resistance (Patent Document 5).

However, although the polyamide-based hot-melt adhesive of Patent Document 5 has high heat resistance in a high temperature environment, the resin easily changes to carbide due to oxidative deterioration during heating and melting during coating, and this carbide is a nozzle of the coating apparatus. May be mixed into the filter medium as a foreign substance, which may reduce the productivity. Further, there is a problem that a large amount of carbide clogs the nozzle of the coating device, and a predetermined coating amount cannot be obtained, resulting in a decrease in the strength of the filter.
Further, in terms of manufacturing process control, it is troublesome in terms of process control to properly use two types of hot melt adhesives for top bonding and edge bonding, and a hot melt adhesive that can be used in both processes has been required.

Japanese Unexamined Patent Publication No. 7-47211 Japanese Unexamined Patent Publication No. 2003-65170 Japanese Unexamined Patent Publication No. 2000-226561 Japanese Unexamined Patent Publication No. 5-103936 Japanese Unexamined Patent Publication No. 10-272329

One embodiment of the present invention is capable of coating at a low coating temperature in top bonding, maintains adhesive strength even in a low viscosity at the time of coating and in a high temperature environment, and in edge bonding, an end plate. It is an object of the present invention to provide a hot melt adhesive which has strong strength in adhering to a filter medium and can be used for both adhesion.

As a result of diligent studies to solve the above problems, the present inventors have found that a hot melt adhesive satisfying the following conditions solves these problems, and completed the present invention. Further, they have found that the hot melt adhesive can be suitably used as an air filter, particularly an air filter for an automobile interior, because it has the above-mentioned characteristics, and completed the present invention.
The present invention includes the following embodiments.
[1] (A) According to ASTM D3236-73, Spindle No. The melt viscosity at 190 ° C. measured using SC4-27 is 1,000 mPa · s or more and 15,000 mPa · s or less.
(B) According to JIS K6863-1994, the softening point measured using silicone oil as a heat medium is 130 ° C or higher and 170 ° C or lower.
(C) In accordance with JIS K7196-991, a cylindrical detection rod with a diameter of 3 mm was applied to a test piece cut out in 5 mm square from a sample sheet molded to a thickness of 2 mm, and nitrogen gas was flowed at a rate of 100 ml / min to load. When the temperature is raised at a rate of 5 ° C./min by applying a load of 10 gf, the temperature at which the test piece softens and the displacement in the contraction direction becomes 0.05 mm is 90 ° C. or higher. Hot melt adhesive.
[2] (D) In accordance with JIS K6850-1999, a hot melt adhesive melted at 180 ° C. is applied to a 10 mm × 25 mm adhesive portion at one end of a 100 mm × 25 mm polypropylene plate in a bead shape with a width of 4 to 5 mm. Within 5 seconds, one end of another polypropylene plate is overlapped with the adhesive portion, and the test piece is pressed at a pressure of 24 kgf for 5 seconds to obtain a test piece. After allowing the test piece to stand at 25 ° C. for 16 hours, both of the test pieces. The adhesive force when the polypropylene plate is pulled in the opposite direction at a speed of 50 mm / min at 80 ° C. is 15 N / cm ² or more.
(E) One of the test pieces is vertically fixed to a jig in a constant temperature bath, a weight of 500 g is attached to the other end, the test piece is allowed to stand at 38 ° C. for 15 minutes, and then rises at a rate of 0.4 ° C./min. The hot melt adhesive according to [1], wherein when warmed, the adhesive portion cannot withstand the load of the weight, and the temperature at which the weight falls is 90 ° C. or higher.
[3] The hot melt adhesive according to [1] or [2], which contains a polyolefin.
[4] The hot melt adhesive according to [3], wherein the polyolefin is polypropylene.
[5] The hot melt adhesive according to any one of [1] to [4], which further contains an antioxidant.
[6] In assembling a filter composed of a pleated filter medium and a frame around the filter medium, it is present between adjacent folds to prevent contact between the folds and / or the filter medium and the frame. The hot melt adhesive according to any one of [1] to [5] used for adhering.
[7] The hot melt adhesive according to [6], wherein the filter medium is a polypropylene non-woven fabric.
[8] The hot melt adhesive according to [6] or [7], wherein the filter is an automobile interior air filter.
[9] A filter assembled by using a pleated filter medium and a frame around the filter medium as constituent parts and using the hot melt adhesive according to any one of [1] to [7].
[10] For automobile interiors, the pleated filter medium and the frame around the filter medium are used as components and assembled using the hot melt adhesive according to any one of [1] to [8]. Air filter.

According to the hot melt adhesive of the present disclosure, it is possible to coat at a low coating temperature of 180 ° C. or less, and since it has a low viscosity at the time of coating, the coating workability is good and the adhesive strength is good even in a high temperature environment. Since it can be used in a high temperature environment and can be used for both top bonding and edge bonding, it can be suitably used for filter applications, especially for automobile air filters.

The first aspect of the present invention (the hot melt adhesive of the present disclosure) is a hot melt adhesive that satisfies the following conditions (A), (B) and (C).
(A) According to ASTM D3236-73, Spindle No. The melt viscosity at 190 ° C. measured using SC4-27 is 1,000 mPa · s or more and 15,000 mPa · s or less.
(B) According to JIS K6863-1994, the softening point measured using silicone oil as a heat medium is 130 ° C or higher and 170 ° C or lower.
(C) In accordance with JIS K7196-991, a cylindrical detection rod with a diameter of 3 mm was applied to a test piece cut out in 5 mm square from a sample sheet molded to a thickness of 2 mm, and nitrogen gas was flowed at a rate of 100 ml / min to load. When a load of 10 gf is applied and the temperature is raised at a rate of 5 ° C./min, the temperature at which the test piece softens and the displacement in the contraction direction becomes 0.05 mm is 90 ° C. or higher.
A hot melt adhesive that satisfies the above conditions (A), (B), and (C) has excellent workability when applied and has good adhesiveness to an adherend, and is used as a filter. When used in, it is easy to apply to the filter medium, the adhesion between the filter medium and the end plate is good, and peeling and falling off are prevented even when a force such as vibration or bending stress is applied. ..
The melt viscosity in (A) is more preferably 2,000 mPa · s or more and 10,000 mPa · s or less.
Further, the softening point in (B) is more preferably 135 ° C. or higher and 165 ° C. or lower.
Further, the temperature at which the test piece in (C) softens and the displacement in the contraction direction becomes 0.05 mm is more preferably 100 ° C. or higher.

In one embodiment of the present invention, the hot melt adhesive is a hot melt adhesive that further satisfies the following conditions (D) and (E).
(D) In accordance with JIS K6850-1999, 5 seconds after applying hot melt adhesive melted at 180 ° C to a 10 mm x 25 mm adhesive portion at one end of a 100 mm x 25 mm polypropylene plate in a bead shape with a width of 4 to 5 mm. Within this period, one end of another polypropylene plate is superposed on the adhesive portion, and the test piece is pressed at a pressure of 24 kgf for 5 seconds to form a test piece. After the test piece is allowed to stand at 25 ° C. for 16 hours, both polypropylene plates of the test piece are placed. The adhesive force when pulled in the opposite direction at a speed of 50 mm / min at 80 ° C. is 15 N / cm ² or more. (E) One of the test pieces is vertically fixed to a jig in a constant temperature bath, and the other is fixed. When a weight of 500 g is attached to the end, left at 38 ° C for 15 minutes, and then the temperature is raised at a rate of 0.4 ° C / min, the adhesive part cannot withstand the load of the weight and the weight falls. The temperature is 90 ° C or higher.
The hot melt adhesive that satisfies the above conditions (D) and (E) has good adhesiveness and excellent durability in a high temperature environment, especially when polypropylene is used as the adherend, and polypropylene. When used for a filter medium made of a non-woven fabric, the filter medium has good adhesion to the end plate, and peeling or falling off is prevented even when the filter is placed in a high temperature environment.
The adhesive strength in (D) is more preferably ^{30 N / cm 2 or more.}

In one embodiment of the invention, the hot melt adhesive further comprises polyolefin.
In the present invention, the "polyolefin" is preferably a polymer of an olefin having 2 to 4 carbon atoms, and either amorphous or crystalline can be used. The polyolefin contains a single polymer of olefins, a copolymer or a mixture thereof. Such polyolefins include, for example, polyethylene, polypropylene, ethylene and propylene copolymers, propylene and 1-butene copolymers, ethylene and 1-butene copolymers, and propylene, ethylene and 1-butene copolymers. Examples thereof include copolymers, which can be used alone or in combination.
Further, as the polyolefin, polypropylene is preferable for the reason of heat-resistant adhesiveness, and polypropylene in the whole polyolefin is preferably contained in an amount of 50% by mass or more.

Here, the number average molecular weight of the polyolefin is not particularly limited as long as it exhibits the performance desired by the present invention, but is preferably 2,000 to 30,000, more preferably 4,000 to 25,000, and 6,000. ~ 25,000 is even more preferable.
Further, the glass transition temperature (hereinafter, “glass transition temperature” in the present specification refers to the calculation of the glass transition start temperature and the glass transition end temperature measured by DSC using the same method as described in DIN 53765. The average temperature) is preferably −20 to −40 ° C.
In the hot melt adhesive of the present disclosure, the content of polyolefin is preferably 70 to 99% by mass, more preferably 75 to 99% by mass, and even more preferably 80 to 99% by mass.

In one embodiment of the present invention, the hot melt adhesive contains polypropylene as the constituent polyolefin. More preferably, it is amorphous polypropylene. The polypropylene has a function of imparting adhesiveness to the hot melt adhesive composition and lowering the viscosity at the time of coating, and any known polypropylene can be used, but ethylene and propylene can be used. Copolymers of, propylene and 1-butene copolymers, and propylene, ethylene and 1-butene copolymers can also be used.

Here, the number average molecular weight of polypropylene is not particularly limited as long as it exhibits the desired performance of the present invention, but is generally preferably 4,000 to 25,000, more preferably 6,000 to 15,000. The melt viscosity at 190 ° C. is preferably 1,500 to 50,000 mPa · s, more preferably 1,500 to 30,000 mPa · s. Further, the glass transition temperature is preferably −20 ° C. to −40 ° C.

In one embodiment of the invention, the hot melt adhesive further comprises an antioxidant.
As the antioxidant, a known antioxidant can be used without particular limitation. For example, a phenol-based antioxidant, an amine-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, and a hydroquinone-based antioxidant can be used. Examples thereof include antioxidants, quinoline-based antioxidants, hydrazines and urea-based antioxidants.
Among these, phenol-based antioxidants and sulfur-based antioxidants are preferable because of their stability in melt viscosity and resistance to coloring when heated, and among phenol-based antioxidants, hindered phenol-based antioxidants are more preferable. preferable.

Examples of the phenolic antioxidant include 2,6-di-t-butyl-p-cresol (BHT), 2,2'-methylenebis (4-methyl-6-t-butylphenol), and 4,4'-. Butylidenebis (3-methyl-6-t-butylphenol), stearyl-β- (3,5-di-t-butyl-4-hydroxylphenol) propionate, tetrakis [methylene-3- (3', 5'-di-) t-butyl-4'-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-4-hydroxybenzyl) benzene, 1,1,3 -Tris (2-methyl-4-hydroxy-5-t-butylphenol) butane, pentaerythyltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,1-bis Examples thereof include (4-oxyphenyl) cyclohexane, dialkylphenol sulfide, alkylphenol condensate and styrenated phenol.
Among these, it is a hindered phenolic antioxidant having one or two t-butyl groups at positions adjacent to the carbon atom to which the phenolic hydroxy group is bonded on the aromatic ring. Pentaerystyltetrax [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is more preferred.

Examples of amine-based antioxidants include N, N'-di-2-naphthyl-p-phenylenediamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, 4,4'-dimethoxydiphenylamine, N, N'. -Diphenyl-p-phenylenediamine, N-phenyl-N'-cyclohexyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, aldol-α-naphthylamine, 4,4'-diaminodiphenylmethane, Examples thereof include acetaldehyde aniline, and reaction products of diphenylamine and acetone.

Phenyl antioxidants include tris (isodecyl) phosphite, tris (tridecyl) phosphite, phenylisooctylphosphite, phenylisodecylphosphite, phenyldi (tridecyl) phosphite, diphenylisooctylphosphite, diphenylisodecyl. Phosphite, Diphenyltridecylphosphite, Triphenylphosphite, Tris (nonylphenyl) phosphite, 4,4'isopropyridene diphenolalkylphosphite, trisnonylphenylphosphite, trisdinonylphenylphosphite, tris (2 , 4-di-t-butylphenyl) phosphite, tris (biphenyl) phosphite, distearyl pentaerythritol diphosphite, di (2,4-di-t-butylphenyl) pentaerythritol diphosphite, di (nonyl) Phenyl) pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, tetratridecyl 4,4'-butylidenebis (3-methyl-6-t-butylphenol) diphosphyte, hexatridecyl 1,1,3- Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butanetriphosphite, 3,5-di-t-butyl-4-hydroxybenzylphosphite diethyl ester, sodium bis (4-t-butylphenyl) Phosphite, Sodium-2,2-Methylene-bis (4,6-di-t-butylphenyl) -Phosphite, 1,3-bis (diphenoxyphosphonyloxy) -benzene and ethylbis phosphite (2, 4-Ditert-butyl-6-methylphenyl) and the like. In addition, oligomer-type and polymer-type compounds having a phosphite structure can also be used.

Examples of sulfur-based antioxidants include 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and 2,4-bis [(octylthio) methyl]-. o-cresol, 2,4-bis [(laurylthio) methyl] -o-cresol, 2,2-bis {[3- (dodecylthio) -1-oxopropoxy] methyl} propane-1,3-diylbis [3- (Dodecylthio) propionate] and 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and the like. In addition, oligomer-type and polymer-type compounds having a thioether structure can also be used.

The antioxidant prevents deterioration of the hot melt adhesive during melting, and as a result, maintains moldability and appearance quality of the filter after molding in filter applications. The hot melt adhesive of the present disclosure contains an antioxidant from the viewpoint of suppressing heat coloring at the time of melting, reducing the difference in hue of the hot melt adhesive applied to the white filter medium, and maintaining the design. Is preferable.
These antioxidants may be used alone or in combination of two or more.

The content of the antioxidant in the hot melt adhesive of the present disclosure is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the hot melt adhesive, and 0.2 to 4 parts by mass. More preferably, 0.3 to 3 parts by mass is further preferable.

In addition to polyolefins and antioxidants, the hot melt adhesives of the present disclosure include waxes such as crystalline polypropylene wax and crystalline polyethylene wax, tackifier components such as tack fire, and fillers as other components. An ultraviolet absorber, a flow modifier, a deodorant, an antibacterial agent, an adhesion improver, a pigment and the like can be added.

(Waxes such as crystalline polypropylene wax and crystalline polyethylene wax)
The "crystalline polypropylene wax" is a waxy crystalline polypropylene.
This number average molecular weight is not particularly limited as long as it exhibits the desired performance of the present invention, but is preferably 2,000 to 20,000, more preferably 2,000 to 10,000, and 2,000 to 7,000. Is even more preferable. The softening point is preferably 120 to 160 ° C, more preferably 140 to 160 ° C.

"Crystalline polyethylene wax" is a waxy crystalline polyethylene.
This number average molecular weight is not particularly limited as long as it exhibits the desired performance of the present invention, but is preferably 1,000 to 10,000, more preferably 1,000 to 4,000, and 1,000 to 3,000. Is even more preferable. The specific gravity is preferably 0.90 to 1.00, more preferably 0.92 to 1.00, and even more preferably 0.95 to 1.00. The softening point is preferably 100 to 130 ° C, more preferably 120 to 130 ° C.

Waxes such as crystalline polypropylene wax and crystalline polyethylene wax can be used as the hot melt adhesive of the present disclosure, and the blending amount thereof is 5 to 30% by mass with respect to the total mass of the hot melt adhesive. Is preferable, and 10 to 20% by mass is more preferable.

(Adhesive-imparting ingredients such as tack fire)
The hot melt adhesive of the present disclosure may contain a tack fire (adhesive imparting agent) from the viewpoint of wettability to the filter medium.
Examples of the tack fire include petroleum resins; rosin derivatives such as rosin ester, gum rosin, tall oil rosin, hydrogenated rosin ester, maleated rosin and disproportionated rosin ester; terpene phenol resin, α-pinene and β-pinene. And terpene-based resins mainly composed of limonene and the like; kumaron-indene-based resins; hydrogenated aromatic copolymers; styrene-based resins; phenol-based resins; xylene-based resins; (meth) acrylic-based polymers and the like.

Above all, it is preferable that the tack fire contains at least one compound selected from the group consisting of a petroleum resin, a rosin derivative and a hydrogenated resin of a terpene resin.
Since these have a white hue, there is no significant difference in hue from the white filter medium, and the design can be maintained.

The content of the tack fire is preferably 1% by mass or more and 70% by mass or less with respect to the total mass of the hot melt adhesive from the viewpoint of thermal cycle durability, adhesiveness at room temperature and handleability, and is preferably 10% by mass. It is more preferably% or more and 65% by mass or less, further preferably 20% by mass or more and 60% by mass or less, and particularly preferably 30% by mass or more and 55% by mass or less.

(Other ingredients)
Examples of the filler include fuming silica, surface-treated fuming silica, precipitated silica, diatomaceous earth, quartz powder, calcium carbonate, carbon black and the like.
By containing the filler, heat resistance, elastic modulus, blocking resistance and the like can be improved.
Examples of the ultraviolet absorber include a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber such as 2- (2-hydroxy-5-methylphenyl) benzotriazole, and the like.

The other components may be used alone or in combination of two or more.
The content of the other components is not particularly limited, but is preferably 5% by mass or less, and more preferably 1% by mass or less, based on the total mass of the hot melt adhesive.

The hot melt adhesive of the present disclosure is used in fields where hot melt adhesives are usually used, for example, in fields such as cardboard, paperwork, laminating wood or non-woven cloth, and assembling parts to metal or plastic. Although it can be used, it is particularly suitable for assembling a filter in which a filter medium such as a non-woven cloth and / or paper is pleated, and the processed filter medium is further fixed to a frame.
The hot melt adhesive of the present disclosure is suitable for applications in which a pleated filter medium is set in a frame and used, for example, for processing filters for air purifiers, humidifiers, vacuum cleaners, salt damage prevention machines, and the like. ..
Further, since the hot melt adhesive of the present disclosure has excellent adhesive durability in a high temperature environment, it can be suitably used for an air filter application for an automobile interior.

An example of a method of assembling a filter using the hot melt adhesive of the present disclosure for a pleated filter medium and a frame is given.
(1) Adhesion to the top The filter medium is pleated, and a hot melt adhesive is applied linearly or in dots to the plate-shaped filter medium as a whole, aiming at the top of the folds in the direction across the direction in which the folds extend, and solidifies. Let me. As a result, the movement of the folds can be suppressed and the contact between the adjacent folds can be prevented.
The adhesive may be applied linearly or in dots near the top of the fold, aiming between the tops of the adjacent folds. A hot melt applicator or a hot melt gun can be used for application.
The plate-shaped filter thus obtained can be curved and processed into a cylindrical shape or a part thereof (semi-cylindrical shape).

(2) Adhesive at the end The plate-shaped pleated filter medium is attached to a frame arranged around it to prevent fluid leakage when used as a filter and to prevent it from falling off during transportation and running. It is preferable to fit and fix it. Therefore, it is preferable that the end plate in the extending direction of the folds of the filter medium is adhered to the end plate constituting the frame. Further, it is preferable that the end portions in the direction in which the folds extend and the end portions in the vertical direction are also bonded to the end plates constituting the frame body.
For this purpose, a narrow space is provided between the end of the filter medium and the end plate, and the adhesive is injected and fixed. However, if a hot melt adhesive is used as the adhesive, for example, the method of injecting from the upper part is adopted, the process time is increased. It is preferable because it shortens.

The filter of the present disclosure is assembled by both the top bonding and the edge bonding, but the order of the top bonding and the edge bonding may be reversed if necessary. Further, the individual end plates and the pleated filter media may be first end-bonded, and the end plates may be assembled into a frame. Further, the frame body may be an integrally molded product molded in a frame shape. In this case, the end bonding is not the end plate but the bonding of each surface constituting the inner surface of the frame body and the pleated filter medium.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these examples.

(Adjustment of hot melt adhesive)
Reference example 1
Set the MS open type kneader manufactured by Moriyama Co., Ltd. with an internal volume of 1.5 liters to 230 ° C., 0.3 parts by mass of a phenol-based antioxidant (antioxidant A) and a sulfur-based antioxidant (antioxidant). B) 0.3 parts by mass and 15 parts by mass of crystalline polypropylene (resin A) are added, melt-mixed, and then 50 parts by mass of amorphous polypropylene (resin B) and 35 parts by mass of amorphous polypropylene (resin D) are sequentially added. The parts were put together and mixed by heating to obtain a hot melt adhesive 1.

Reference examples 2-9
The types and amounts of the resin and the antioxidant, and the types and amounts of the additives were changed as shown in Table 1 to prepare hot melt adhesives 2 to 4 and 6 to 9.

Each resin, each antioxidant and each additive used in the above reference example are as follows.
(Resin A) Crystalline polypropylene: number average molecular weight is 10,000, glass transition temperature is 14.
The melt viscosity at 5 ° C and 190 ° C is 42,000 mPa · s.
(Resin B) Amorphous polypropylene: The softening point is 152 ° C. and the melt viscosity at 190 ° C. is 1,500 mPa · s.
(Resin C) Amorphous polypropylene: The softening point is 141 ° C. and the melt viscosity at 190 ° C. is 3,000 mPa · s.
(Resin D) Amorphous polypropylene: The softening point is 124 ° C. and the melt viscosity at 190 ° C. is 2,700 mPa · s.
(Resin E) Amorphous polypropylene: The softening point is 107 ° C. and the melt viscosity at 190 ° C. is 50,000 mPa · s.
(Resin F) Crystalline polyethylene: melting point 98 ° C., melt flow index 145 g / 10 minutes (temperature 190 ° C., load 2.16 kg)
(Resin G) Ethylene-vinyl acetate copolymer resin: vinyl acetate 14%, melting point 77 ° C., melt flow index 2,500 g / 10 minutes (temperature 190 ° C., load 2.16 kg)
(Resin H) Polyamide resin: The softening point is 135 ° C. and the melt viscosity at 190 ° C. is 4,800 mPa · s.

(Antioxidant A) Hindered Phenolic Antioxidant (Antioxidant B) Sulfur Antioxidant (Additive A) Tuck Fire (Hydrogenated DCPD Resin): Softening point is 105 ° C.
(Additive B) Polypropylene wax: Softening point is 152 ° C

Examples 1 to 5, Comparative Examples 1 to 4
(Evaluation of physical properties of hot melt adhesive)
(A) According to ASTM D3236-73, Spindle No. Melt viscosity at 190 ° C. measured using SC4-27:
Brookfield RVT is used as the Brookfield viscometer. The rotation speed was measured at 2.5 rpm in Comparative Example 2 and 20 rpm in the others.
(B) Softening point measured using silicone oil as a heat medium in accordance with JIS K6863-1994:
The temperature of the test room is 23 ± 5 ° C and the relative humidity is 40 to 70%.
(C) A cylindrical detection rod with a diameter of 3 mm was applied to a test piece cut out in 5 mm square from a sample sheet molded to a thickness of 2 mm in accordance with JIS K7196-991, and nitrogen gas was flowed at a rate of 100 ml / min to load the load. Temperature when the test piece softens and the displacement in the contraction direction becomes 0.05 mm when the temperature is raised at a rate of 5 ° C./min by multiplying by 10 gf:
The measurement uses a thermomechanical analyzer TMA-60 (manufactured by Shimadzu Corporation).
(D) In accordance with JIS K6850-1999, 5 seconds after applying hot melt adhesive melted at 180 ° C to a 10 mm x 25 mm adhesive portion at one end of a 100 mm x 25 mm polypropylene plate in a bead shape with a width of 4 to 5 mm. Within this, one end of another polypropylene plate is overlapped with the adhesive portion, and the test piece is pressed at a pressure of 24 kgf for 5 seconds to obtain a test piece. After allowing the test piece to stand at 25 ° C. for 16 hours, both polypropylene plates of the test piece are placed together. Adhesive strength when pulled in the opposite direction at 80 ° C. at a speed of 50 mm / min:
The thickness of the applied adhesive is about 0.2 mm. The measurement uses Autograph AGS-X (manufactured by Shimadzu Corporation).
(E) One of the test pieces is vertically fixed to a jig in a constant temperature bath, a weight of 500 g is attached to the other end, the test piece is allowed to stand at 38 ° C. for 15 minutes, and then rises at a rate of 0.4 ° C./min. When warmed, the adhesive part cannot withstand the load of the weight, and the temperature when the weight falls:
The measurement uses a high-spec oven EH-602 (manufactured by Kusumoto Kasei Co., Ltd.).
The results of these physical property evaluations are shown in Table 2.

(Performance evaluation of hot melt adhesive and filter)
(1) Heat Stability Test of Hot Melt Adhesive Put an aluminum foil cup in a metal container with a volume of 150 cc, and put 30 g of hot melt adhesive in it. It is allowed to stand in a hot air circulation type constant temperature bath adjusted to 190 ° C. After 24 hours, the sample was taken out from the constant temperature bath, the aluminum foil was removed, the surface of the sample was pecked with tweezers, and the state of the surface was visually observed.
The one without leather on the surface was designated as A, and the one with leather was designated as F.
(2) Heat resistance test of filter A sample filter medium was prepared by bending a polypropylene non-woven fabric and pleating it. The hot melt adhesive was linearly applied to the sample filter medium in the direction perpendicular to the direction in which the folds extended (horizontal direction). As a result, a substantially uniform layer of hot melt adhesive was formed on the surface of the filter medium.
Next, both end faces of the sample filter medium fixed with the hot melt adhesive in the extending direction of the folds and the polypropylene end plates were adhered with the same hot melt adhesive as described above to obtain a sample filter.
The obtained sample filter with an end plate was allowed to stand in a hot air circulation type constant temperature bath adjusted to 80 ° C. for 72 hours, and then the state of adhesion between the end of the filter medium and the end plate of the filter was confirmed. The one with no abnormality was designated as A, and the one with confirmed peeling was designated as F.
The results of these performance evaluations are shown in Table 2.

As is clear from Examples 1 to 5, the spindle No. 1 is based on (A) ASTM D3236-73 of the present invention. The melt viscosity at 190 ° C. measured using SC4-27 is 1,000 mPa or more and 15,000 mPa or less, and the softening point measured using silicone oil as a heat medium is 130, in accordance with (B) JIS K6863-1994. ℃ or more and 170 ℃ or less, and in accordance with (C) JIS K7196-19 / BR> X1, a cylindrical detection rod with a diameter of 3 mm was applied to a test piece cut out in 5 mm square from a sample sheet molded to a thickness of 2 mm, and nitrogen was added. The temperature at which the test piece softens and the displacement in the contraction direction becomes 0.05 mm when the gas is flowed at a rate of 100 ml / min, a load load of 10 gf is applied, and the temperature is raised at a rate of 5 ° C./min. In Examples 1 to 5, which satisfy the three requirements of 90 ° C. or higher, the heat resistance test of the filter is good and the heating stability is good.

Further, as is clear from Examples 1 to 4, hot melt adhesive melted at 180 ° C. to a 10 mm × 25 mm adhesive portion at one end of a 100 mm × 25 mm polypropylene plate in accordance with (D) JIS K6850-199 of the present invention. After applying the agent in a bead shape with a width of 4 to 5 mm, one end of another polypropylene plate is overlapped with the adhesive portion within 5 seconds, and the test piece is pressed at a pressure of 24 kgf for 5 seconds to obtain a test piece, and the test piece is at 25 ° C. After standing for 16 hours, the adhesive strength when both polypropylene plates of the test piece were pulled in the opposite directions at a speed of 50 mm / min at 80 ° C. was 15 N / cm ² or more, and (E) one of the test pieces was used. Fix it vertically to the jig in the constant temperature bath, attach a weight of 500 g to the other end, let it stand at 38 ° C for 15 minutes, and then raise the temperature at a rate of 0.4 ° C / min. In Examples 1 to 4, which cannot withstand the load of the weight and satisfy the two requirements that the temperature when the weight falls is 90 ° C. or higher, the heating stability test is also good, and the hot melt adhesive is used in a high temperature environment. It has been proved that the deterioration of the can be prevented.

On the other hand, Comparative Examples 1 to 4 which do not satisfy the above requirements (A) to (C) have poor heat resistance test results of the filter and are used for filters placed in a high temperature environment, for example, for loading in an automobile. Turns out to be unsuitable.

Claims

(A) According to ASTM D3236-73, Spindle No. The melt viscosity at 190 ° C. measured using SC4-27 is 1,000 mPa · s or more and 15,000 mPa · s or less.
(B) According to JIS K6863-1994, the softening point measured using silicone oil as a heat medium is 130 ° C or higher and 170 ° C or lower.
(C) In accordance with JIS K7196-991, a cylindrical detection rod with a diameter of 3 mm was applied to a test piece cut out in 5 mm square from a sample sheet molded to a thickness of 2 mm, and nitrogen gas was flowed at a rate of 100 ml / min to load. When the temperature is raised at a rate of 5 ° C./min by applying a load of 10 gf, the temperature at which the test piece softens and the displacement in the contraction direction becomes 0.05 mm is 90 ° C. or higher. Hot melt adhesive.
(D) In accordance with JIS K6850-1999, 5 seconds after applying hot melt adhesive melted at 180 ° C to a 10 mm x 25 mm adhesive portion at one end of a 100 mm x 25 mm polypropylene plate in a bead shape with a width of 4 to 5 mm. Within this, one end of another polypropylene plate is overlapped with the adhesive portion, and the test piece is pressed at a pressure of 24 kgf for 5 seconds to obtain a test piece. After allowing the test piece to stand at 25 ° C. for 16 hours, both polypropylene plates of the test piece are placed together. The adhesive force when pulled in the opposite direction at 80 ° C. at a speed of 50 mm / min is 15 N / cm 2 or more.
(E) One of the test pieces is vertically fixed to a jig in a constant temperature bath, a weight of 500 g is attached to the other end, the test piece is allowed to stand at 38 ° C. for 15 minutes, and then rises at a rate of 0.4 ° C./min. The hot melt adhesive according to claim 1, wherein when warmed, the adhesive portion cannot withstand the load of the weight, and the temperature at which the weight falls is 90 ° C. or higher.
The hot melt adhesive according to claim 1 or 2, which contains polyolefin.
The hot melt adhesive according to claim 3, wherein the polyolefin is polypropylene.
The hot melt adhesive according to any one of claims 1 to 4, further comprising an antioxidant.
In assembling a filter consisting of a pleated filter medium and a frame around the filter medium, it is present between adjacent folds to prevent contact between the folds and / or glues the filter medium to the frame. The hot melt adhesive according to any one of claims 1 to 5, which is used for this purpose.
The hot melt adhesive according to claim 6, wherein the filter medium is a polypropylene non-woven fabric.
The hot melt adhesive according to claim 6 or 7, wherein the filter is an air filter for an automobile interior.
A filter assembled by using a pleated filter medium and a frame around the filter medium as components and using the hot melt adhesive according to any one of claims 1 to 7.
An automobile interior air filter assembled by using a pleated filter medium and a frame around the filter medium as components and using the hot melt adhesive according to any one of claims 1 to 8.