JPWO2020137573A1 - Flame-retardant adhesive and flame-retardant adhesive tape - Google Patents

Abstract

The present invention provides a flame-retardant adhesive and a thin-walled adhesive that can achieve both adhesiveness and flame retardancy at a high level even when used for a flame-retardant adhesive tape having a thin filmed adhesive layer. It is an object of the present invention to provide a flame-retardant adhesive tape capable of achieving both adhesiveness and flame retardancy at a high level even if it is formed. The flame-retardant pressure-sensitive adhesive of the present invention has 100 parts by mass of a pressure-sensitive adhesive component and 65 parts by mass or more of ammonium polyphosphate having a particle size D95 of particles corresponding to a cumulative 95% from the small diameter side of the cumulative particle size distribution of 20.0 μm or less. In the X-ray diffraction measurement of ammonium polyphosphate, the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° was set to the diffraction angle 2θ = 14.6 ± 0.2 °. The value divided by the peak intensity value is 1.4 or more. Further, the flame-retardant adhesive tape of the present invention is characterized by having a pressure-sensitive adhesive layer formed by the above-mentioned flame-retardant pressure-sensitive adhesive on at least one surface of a base material.

Description

The present invention relates to flame-retardant adhesives and flame-retardant adhesive tapes.

Due to the remarkable progress in electronics technology, electrical, electronic, and OA equipment have become highly integrated and high-performance, and are used in the above equipment to reduce the risk of ignition due to high temperature and heat storage inside these equipment or to prevent ignition. High flame retardancy is also required for the adhesive tape to be used. In addition, various studies have been conducted on the flame retardancy of plastic materials in various fields such as home appliances, vehicles, and building materials, and the adhesive tape used for fixing them is also required to have high flame retardancy.
As such an adhesive tape, an adhesive containing ammonium polyphosphate has been proposed (for example, Patent Document 1 and the like), and it is said that high flame retardancy can be exhibited by this.

JP-A-11-1669

Here, in recent years, for example, further high integration and weight reduction have progressed in the above-mentioned applications, and adhesive tapes are required to have not only high flame retardancy of UL94VTM-0 level but also thinning. ing. In order to thin the adhesive tape, it is necessary to thin not only the base material of the adhesive tape but also the adhesive layer. However, when the pressure-sensitive adhesive layer is thinned, the adhesiveness and flame retardancy of the adhesive tape are in a trade-off relationship, and it has been difficult to achieve both of these with the above-mentioned conventional techniques.

Therefore, the present invention provides a flame-retardant adhesive and a flame-retardant adhesive that can achieve both the adhesiveness and the flame retardancy at a high level even when the adhesive layer is thinned into a flame-retardant adhesive tape. An object of the present invention is to provide a flame-retardant adhesive tape capable of achieving both adhesiveness and flame retardancy at a high level even if the thickness is reduced.

As a result of diligent studies to solve the above-mentioned problems of the prior art, the present inventors have obtained the following findings and found the present invention. That is, in order to ensure the flame retardancy of the thinned pressure-sensitive adhesive layer, it is preferable to use type II ammonium polyphosphate among various flame retardants, but the actually thinned pressure-sensitive adhesive layer When type II ammonium polyphosphate is contained, sufficient adhesiveness cannot be obtained due to the relatively large particles present in the particles, and relatively large particles are not generated in the particles of type II polyphosphate. It was found that it is difficult to manufacture industrially. Further, when the present inventors use type II ammonium polyphosphate as a pressure-sensitive adhesive, if the particles are, for example, crushed into small pieces, the stickiness may be obtained but sufficient flame retardancy may not be ensured. In such a case, it was found that type I ammonium polyphosphate, which is less effective in improving flame retardancy, is produced in type II ammonium polyphosphate. Furthermore, the inventors have found that even if type I ammonium polyphosphate is generated in type II ammonium polyphosphate, there is an acceptable content in flame retardancy. Based on these findings, the present inventors have assumed that relatively fine particles of type II ammonium polyphosphate are used to thin the adhesive tape, and in order to ensure flame retardancy, the present inventors have type II. We came up with the idea of defining the permissible amount of type I ammonium polyphosphate content in ammonium polyphosphate in the above by using X-ray diffraction measurement.
That is, the invention of the present application is as follows.

[1] Containing 100 parts by mass of the adhesive component and 65 parts by mass or more of ammonium polyphosphate having a particle size D95 of particles corresponding to a cumulative 95% from the small diameter side of the cumulative particle size distribution of 20.0 μm or less.
In the X-ray diffraction measurement of ammonium polyphosphate, the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° is divided by the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 °. A flame-retardant adhesive having a value of 1.4 or more.
[2] The flame-retardant pressure-sensitive adhesive according to [1] above, wherein the ammonium polyphosphate is classified.
[3] The flame-retardant pressure-sensitive adhesive according to the above [1] or [2], which contains a metal hydroxide.
[4] The flame-retardant pressure-sensitive adhesive according to any one of the above [1] to [3], which contains an aliphatic polyhydric alcohol and / or an ester of a rosin compound and an aliphatic polyhydric alcohol.
[5] A flame-retardant adhesive tape having a pressure-sensitive adhesive layer formed of the flame-retardant pressure-sensitive adhesive according to any one of the above [1] to [4] on at least one surface of a base material.

According to the present invention, a flame-retardant adhesive that can achieve both adhesiveness and flame retardancy at a high level even when used for a flame-retardant adhesive tape in which the adhesive layer is thinned, and It is possible to provide a flame-retardant adhesive tape capable of achieving both adhesiveness and flame retardancy at a high level even if the thickness is reduced.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the present embodiment.

《Flame-retardant adhesive》
The flame-retardant pressure-sensitive adhesive of the present embodiment has 100 parts by mass of the adhesive component and 65 parts by mass or more of ammonium polyphosphate in which the particle size D95 of the particles corresponding to the cumulative 95% from the small diameter side of the cumulative particle size distribution is 20.0 μm or less. And contains,
In the X-ray diffraction measurement of ammonium polyphosphate, the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° is divided by the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 °. The value obtained is 1.4 or more.
As a result, when the flame-retardant adhesive (hereinafter, also simply referred to as “adhesive”) is used as the adhesive layer of the thin-walled flame-retardant adhesive tape (hereinafter, also simply referred to as “adhesive tape”). Can achieve both adhesiveness and flame retardancy at a high level.

-Adhesive component-
The adhesive component of the present embodiment is not particularly limited, and examples thereof include an acrylic adhesive component, a urethane adhesive component, a synthetic rubber adhesive component, a natural rubber adhesive component, and a silicone adhesive component. In the present embodiment, an acrylic adhesive component is preferable because a relatively strong adhesive force can be easily obtained.

The acrylic adhesive component is not particularly limited, and includes, for example, at least one acrylic polymer containing a (meth) acrylic acid alkyl ester monomer as a monomer unit. The (meth) acrylic acid alkyl ester monomer is, for example, a (meth) acrylic acid alkyl ester in which the alkyl group has 2 to 14 carbon atoms, and examples thereof are not particularly limited, but ethyl acrylate and acrylic. Examples thereof include propyl acid, butyl acrylate, isobutyl acrylate, isoamyl acrylate, hexyl acrylate, octyl acrylate, isonoryl acrylate, isodecyl acrylate, butyl methacrylate, hexyl methacrylate, isodecyl methacrylate, lauryl methacrylate and the like. ..
In addition, in this specification, "(meth) acrylic acid alkyl ester" means acrylic acid alkyl ester or methacrylic acid alkyl ester.

Acrylic acid, maleic anhydride, 2-hydroxyethyl (meth) acrylate and other monomers having a carboxyl group or a hydroxyl group can be copolymerized with the acrylic polymer. As a result, the structural units derived from these monomers serve as cross-linking points in the acrylic polymer, and the hardness of the adhesive component can be adjusted to develop the desired adhesive force.

The acrylic polymer is not particularly limited, and for example, vinyl acetate, acrylonitrile, acrylamide, styrene and the like can be copolymerized to adjust the cohesive force of the acrylic polymer.

The acrylic polymer can be polymerized by using a radical polymerization method such as solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization and the like without particular limitation. Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide, lauroyl peroxide, and bis (4-tert-butylcyclohexyl) peroxydicarbonate, 2,2'-azobisisobutyronitrile, and 2,2'-azobis. (2-Methylbutyronitrile), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovalerian acid), 2,2'-azobis (2-methylpropionate) Azo-based polymerization initiators such as acid) dimethyl and azobis (2,4-dimethylvaleronitrile) (AVN) can be used.

The acrylic polymer can be crosslinked by containing a crosslinkable agent. Examples of the cross-linking agent include epoxy-based cross-linking agents and polyisocyanate compounds such as aliphatic diisocyanates, aromatic diisocyanates and aromatic triisocyanates. Further, a cross-linking accelerator made of an organometallic compound or the like can be added to those having a slow cross-linking reaction. The cohesive force can be improved by cross-linking the acrylic polymer.

-Ammonium polyphosphate-
The flame-retardant pressure-sensitive adhesive of the present embodiment contains a predetermined ammonium polyphosphate. As a result, flame retardancy can be ensured even with an adhesive tape having a thin adhesive layer.
The content of ammonium polyphosphate is 65 parts by mass or more, preferably 70 parts by mass or more, and more preferably 80 parts by mass or more with respect to 100 parts by mass of the above-mentioned adhesive component. By setting the content to 65 parts by mass or more, the desired flame retardancy can be ensured. The upper limit of the content is not particularly limited from the viewpoint of obtaining flame retardancy, but when the content is excessively increased with respect to the adhesive component, the content is applied to the surface of the adhesive layer when the adhesive tape is used. Since the particles may be exposed and the adhesive strength may decrease, the amount is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, and further preferably 150 parts by mass or less.
In this specification, the standard for the content of each component (for example, adhesive component) is based on the non-volatile component (solid content).

The particle size D95 of the particles of ammonium polyphosphate corresponding to a cumulative 95% from the small diameter side of the cumulative particle size distribution is 20.0 μm or less, preferably 19.0 μm or less, and more preferably 15.0 μm or less. By setting the particle size D95 to 20.0 μm or less, the number of particles having a relatively large particle size is reduced, so that the spacer effect due to the relatively large particles is suppressed, and even an adhesive tape having a thin adhesive layer is adhered. Sex can be ensured.
The lower limit of the particle size D95 is not particularly limited from the viewpoint of ensuring adhesiveness, but if the particle size D95 is too low, fine powder is formed, and the specific surface area increases, resulting in poor dispersion or adhesion. Since there is a risk of poor coating due to thickening of the agent, 0.1 μm or more is preferable, 1.0 μm or more is more preferable, and 3.0 μm or more is further preferable.
Further, the particle size D50 of the particles of ammonium polyphosphate corresponding to a cumulative 50% from the small diameter side of the cumulative particle size distribution is preferably 10.0 μm or less, more preferably 8.0 μm or less, still more preferably 7. It is 5.5 μm or less. By setting the particle size D50 to 10.0 μm or less, sufficient adhesiveness can be ensured even with an adhesive tape having a thin adhesive layer.
The particle size (D95, D50, etc.) of the particles accumulating from the small diameter side of the cumulative particle size distribution and corresponding to a predetermined ratio can be measured by the method described in Examples described later.

Further, in the present embodiment, the particles of ammonium polyphosphate having a particle diameter of 20 μm or more are preferably 1% by mass or less in the non-volatile component of the flame-retardant pressure-sensitive adhesive from the viewpoint of further ensuring the adhesiveness, and more preferably. It is 0.1% by mass or less, and more preferably not contained.

Ammonium polyphosphate divides the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° by the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 ° in the X-ray diffraction measurement. The value is 1.4 or more. The peak appearing at the diffraction angle 2θ = 15.5 ± 0.2 ° of ammonium polyphosphate is a peak characteristically observed in type II ammonium polyphosphate, and the diffraction angle 2θ = 14.6 ±. The 0.2 ° peak is a peak characteristically observed in type I and type II ammonium polyphosphates. That is, in the present invention, by defining the relationship between the peak intensity values, it is assumed that the ammonium polyphosphate contains type II, and the flame retardancy is allowed in the ammonium polyphosphate. It defines the content of type I ammonium polyphosphate, which has a low contribution. Therefore, in the present embodiment, by setting the ratio of each peak to the above relationship, the content of type I ammonium polyphosphate present in the type II ammonium polyphosphate can be suppressed, so that the pressure-sensitive adhesive layer can be formed. Flame retardancy can be ensured even with a thin adhesive tape.
Further, in the present embodiment, from the same viewpoint, the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° is set to the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 °. The divided value is preferably 1.5 or more, more preferably 1.6 or more, and further preferably 2.0 or more.
In the present embodiment, the value obtained by dividing the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° by the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 ° is the above. The larger the value is, the more preferable the upper limit value is not particularly limited, but the value can be set to 2.8 or less. As described above, in industrial production, particles having a relatively large particle size may be contained in the particles of type II ammonium polyphosphate, but in the production process, type II ammonium polyphosphate has a relatively large particle size. Large particles are likely to grow, in other words, relatively large particles are likely to have a high content of type II ammonium polyphosphate in the particles. Then, in the process of satisfying the predetermined range of the particle diameter D95, the relatively large particles tend to decrease, and when the particles decrease, the peak of the diffraction angle 2θ = 15.5 ± 0.2 °. The value obtained by dividing the intensity value by the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 ° tends to be 2.8 or less.
The peak intensity value of a predetermined diffraction angle 2θ in the X-ray diffraction measurement can be measured by the method described in Examples described later.

The ammonium polyphosphate of the present embodiment is not particularly limited as long as it satisfies the above-mentioned particle size and a predetermined ratio of the diffraction angle in the X-ray diffraction measurement, and for example, the degree of polymerization of phosphoric acid is 500 to 2000. , The surface of which is coated with melamine / formaldehyde resin or the like, and can be used in the form of an easily fluid, poorly water-soluble powder.

Here, in the present embodiment, in order for ammonium polyphosphate to satisfy the relationship between a predetermined particle size and a peak intensity value in the X-ray diffraction measurement, type II ammonium polyphosphate particles produced by a known method are used. It can be obtained by crushing and classifying. Specifically, the crushing method is not particularly limited, and is represented by a media type disperser / crusher such as a bead mill, a ball mill, an attritor, a planetary mill, and a vibration mill, a mortar type grinder, and a jet mill. A non-media type disperser / crusher can be used. As the pulverization method, either a wet method or a dry method can be used, but wet pulverization is preferable from the viewpoint of easy dispersibility after pulverization, recovery of pulverized material, and good handling. The material of the media when the media type disperser / crusher is used is not particularly limited, but steel, glass, alumina, zirconia, silicon nitride and the like can be used. The diameter of the media is not particularly limited, but the diameter of the media used is preferably φ5 mm or less, more preferably φ3 mm or less, from the viewpoint of efficiently atomizing while suppressing the decrease of type II polyphosphate ammonium due to excessive crushing. , More preferably φ1 mm or less. The pulverization is preferably carried out under mild conditions such as shortening the pulverization time or pulverizing while cooling.
The classification method is not particularly limited, and examples thereof include a classification method using gravity, centrifugal force, inertial force, and the like, and a classification method using a sieve. In addition, from the viewpoint of precisely controlling the classification point, when performing dry classification, a forced vortex type classifier (Aerofine Classifier, manufactured by Nisshin Engineering Co., Ltd .; Micron Separator, manufactured by Hosokawa Micron Co., Ltd .; Turboplex, manufactured by Hosokawa Micron Co., Ltd .; etc.) ) Or an inertial force field classifier using the Coanda effect (Elbow Jet Mill, manufactured by Nittetsu Mining Co., Ltd .; Cliffis, manufactured by Hosokawa Micron Co., Ltd.) can be used.
When classifying, a flame retardant other than ammonium polyphosphate, a flame retardant aid, or the like may be contained, or the dispersion may be wet-classified after being dispersed in an arbitrary dispersion medium. ..
In the present embodiment, since ammonium polyphosphate can preferably satisfy the predetermined relationship between the predetermined particle size and the peak intensity value in the X-ray diffraction measurement, it is preferable to use the classified ammonium polyphosphate.

-Metal hydroxide-
The flame-retardant pressure-sensitive adhesive of the present embodiment can contain a metal hydroxide. Thereby, the flame retardancy can be further improved.
The content of the metal hydroxide is preferably 0.1 part by mass or more, more preferably 25 parts by mass or more, still more preferably 50 parts by mass or more, and particularly preferably 50 parts by mass or more, based on 100 parts by mass of the adhesive component. Is 60 parts by mass or more. By setting the content to 0.1 parts by mass or more, the flame retardancy can be further improved.
The content is not particularly limited from the viewpoint of improving flame retardancy, but if the content is excessively increased with respect to the adhesive component, it will be applied to the surface of the adhesive layer when the adhesive tape is used. Since the particles may be exposed and the adhesive strength may decrease, the amount is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, further preferably 150 parts by mass or less, and particularly preferably 100 parts by mass. It is a department.

The metal hydroxide is not particularly limited, and for example, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, zinc hydroxide, copper hydroxide, and water. Examples thereof include vanadium oxide and tin hydroxide. Among these, aluminum hydroxide is preferable because it can separate water at a relatively low temperature and thereby exhibit high flame retardancy.
In addition, one kind or two or more kinds of metal hydroxides can be used.

The metal hydroxide may be subjected to a surface treatment such as a coupling treatment or a stearic acid treatment in order to improve the dispersibility in the adhesive component. Further, the particle size D95 of a component that can exist as a solid in a pressure-sensitive adhesive such as a metal hydroxide and an aliphatic polyhydric alcohol described later is preferably 20.0 μm or less. The shape of the metal hydroxide includes a spherical shape, a needle shape, a flake shape, and the like.

− Aliphatic polyhydric alcohol −
The flame-retardant pressure-sensitive adhesive of the present embodiment can contain an aliphatic polyhydric alcohol. As a result, the flame-retardant effect of ammonium polyphosphate and, by extension, the flame-retardant property of the adhesive can be improved.
The content of the aliphatic polyhydric alcohol is preferably 5.0 parts by mass or more, more preferably 10.0 parts by mass or more, and further preferably 15.0 parts by mass or more with respect to 100 parts by mass of the adhesive component. It is particularly preferably 16.0 parts by mass or more. By setting the content to 5.0 parts by mass or more, the flame retardancy can be further improved.
The content is not particularly limited from the viewpoint of improving flame retardancy. However, the aliphatic polyhydric alcohol can improve the flame retardancy by coexisting with ammonium polyphosphate, but the excess may become a flammable component. Therefore, 100 parts by mass of ammonium polyphosphate is used. It is preferably parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less.

The aliphatic polyhydric alcohol is not particularly limited. For example, specific examples of the aliphatic polyhydric alcohol include ethylene glycol, glycerin, pentaerythritol, dipentaerythritol, tripentaerythritol, and polyglycerol (triglycerol to hexaglycerol). , Ditrimethylolpropane, xylitol, sorbitol, mannitol and the like. Among these, dipentaerythritol is preferable because it has high bleed resistance to water and can efficiently form char with ammonium polyphosphate.
In addition, one kind or two or more kinds of aliphatic polyhydric alcohols can be used.

-Esters of rosin compounds and aliphatic polyhydric alcohols-
The flame-retardant pressure-sensitive adhesive of the present embodiment can contain an ester of a rosin compound and an aliphatic polyhydric alcohol. As a result, the adhesiveness can be further imparted, and the flame-retardant effect of ammonium polyphosphate and the flame-retardant property of the adhesive can be improved.
The content of the ester of the rosin compound and the aliphatic polyhydric alcohol is preferably 0.1 part by mass or more, more preferably 10.0 parts by mass or more, and further preferably 10.0 parts by mass or more with respect to 100 parts by mass of the adhesive component. It is preferably 20.0 parts by mass or more. By setting the content to 0.1 parts by mass or more, the flame retardancy can be further improved.
The content is not particularly limited from the viewpoint of improving flame retardancy, but is preferably 100 parts by mass or less, more preferably 70.0 parts by mass or less, and further preferably 50.0 parts by mass. It is as follows.

Examples of the rosin-based compound in the ester form of the rosin-based compound and the aliphatic polyhydric alcohol include rosin monomer, disproportionated rosin, polymerized rosin, hydrogenated rosin and partially disproportionated rosin. Examples of the aliphatic polyhydric alcohol include the above-mentioned aliphatic polyhydric alcohols, among which diethylene glycol, glycerin, pentaerythritol and the like are preferable, and pentaerythritol is more preferable. As the rosin compound and the aliphatic polyhydric alcohol, one kind or two or more kinds can be used.

-Other ingredients-
The flame-retardant pressure-sensitive adhesive of the present embodiment can contain a melamine derivative such as melamine cyanurate within a range that does not impair the adhesive performance, thereby further improving the flame-retardant property or increasing the content of ammonium polyphosphate. It can also be reduced.
Further, it is also possible to improve the adhesive strength to the non-polar adherend by containing the tackifier resin within a range that does not reduce the required flame retardancy. Examples of these resins include terpene resins, terpene phenol resins, rosin resins, petroleum resins, kumaron-inden resins, phenol resins and the like. As the shape, a solid or a viscous liquid at room temperature can be used, and the compound type may be used alone or in combination of two or more.

-Physical characteristics of flame-retardant adhesive-
The flame-retardant pressure-sensitive adhesive of the present embodiment uses the flame-retardant pressure-sensitive adhesive and has a thickness of 20 μm on one side of a base material (thickness: 12.5 μm, polyimide film (Capton 50H, manufactured by Toray Dupont Co., Ltd.)). A test piece having an adhesive layer formed on it, and a test piece having a 20 μm thick adhesive layer formed on both sides of a base material (16 μm thick, rayon non-woven fabric (DT-6, manufactured by Papilia Nippon Paper Co., Ltd.)). It is preferable that the flame retardancy of any of the test pieces measured according to the VTM test described in the UL94 standard is UL94VTM-0 or higher.
The flame-retardant adhesive of the present embodiment has a thickness of 16 μm and a 180 ° peel when a 20 μm-thick adhesive layer is formed on both sides of a rayon-made non-woven fabric (DT-6, manufactured by Papilia Nippon Paper Industries Co., Ltd.). The adhesive strength is preferably 5N or more. The peel adhesive force can be obtained by the method described in Examples described later.
Further, the flame-retardant pressure-sensitive adhesive of the present embodiment has a viscosity of 2000 mPa · s or less measured at 23 ° C. by a B-type viscometer in a solution prepared by diluting with ethyl acetate so as to have a solid content of 30%. Is preferable.

-Manufacturing method of flame-retardant adhesive-
The flame-retardant pressure-sensitive adhesive of the present embodiment is not particularly limited, and is produced, for example, by adding a predetermined ammonium polyphosphate and optionally a metal hydroxide to the pressure-sensitive adhesive component and stirring and dispersing them with a high-speed disperser. can do.

《Flame-retardant adhesive tape》
The flame-retardant adhesive tape of the present embodiment is characterized by having a pressure-sensitive adhesive layer formed by the flame-retardant pressure-sensitive adhesive of the embodiment of the present invention described above on at least one surface of a base material. As a result, even when the pressure-sensitive adhesive layer is thinned, its adhesiveness and flame retardancy can be compatible at a high level.

The base material of the flame-retardant adhesive tape of the present embodiment is not particularly limited, and includes, for example, a resin sheet, a non-woven fabric, paper, a metal foil, a woven fabric, a rubber sheet, a foam sheet, and a laminate thereof (particularly, a resin sheet). Laminated body) and the like. Examples of the resin constituting the resin sheet include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, and ethylene-. Vinyl acetate copolymer (EVA), polyamide (nylon), total aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene terephide (PPS), fluororesin, polyetheretherketone (PEEK) ) Etc. can be mentioned. Examples of the non-woven fabric include non-woven fabrics of natural fibers (cellulose-based fibers); non-woven fabrics of synthetic resin fibers such as polypropylene resin fibers, polyethylene resin fibers, and polyester-based resin fibers. Examples of the metal foil include copper foil, stainless steel foil, aluminum foil and the like. Examples of paper include Japanese paper and kraft paper.
As these base materials, those subjected to treatments such as nonflammability and self-extinguishing properties can also be used.

The flame-retardant adhesive tape of the present embodiment has a pressure-sensitive adhesive layer formed by the flame-retardant pressure-sensitive adhesive described above, and the pressure-sensitive adhesive layer of the flame-retardant pressure-sensitive adhesive tape has a thickness of 20.0 μm or less. It is preferably 18.0 μm or less, and more preferably 13.0 μm or less. In the case of an adhesive layer having such a thickness, it is difficult to achieve both adhesiveness and flame retardancy with a conventional adhesive tape using an adhesive, and it is not suitable. However, the flame retardant adhesive tape of the present embodiment has this. Even with such a thickness, it can be appropriately produced.

When the flame-retardant adhesive tape of the present embodiment has an adhesive layer on one side of the base material, the total thickness of the base material and the pressure-sensitive adhesive layer can be 30.0 μm or less, preferably. It is 25.0 μm or less, more preferably 20.0 μm or less. When the pressure-sensitive adhesive layers are provided on both sides of the base material, the total thickness of the base material and the pressure-sensitive adhesive layer can be 50.0 μm or less, preferably 40.0 μm or less, more preferably. Is 30.0 μm or less.

A release film may be laminated on the flame-retardant adhesive tape of the present embodiment to protect the adhesive layer. The release film is not particularly limited, and is, for example, on at least one or both sides of a synthetic resin film such as polyethylene, polypropylene, polyester film, paper, non-woven fabric, cloth, foam sheet or metal foil, and a base material such as a laminate thereof. , A silicone-based treatment for enhancing the peelability from the pressure-sensitive adhesive, a long-chain alkyl-based treatment, a fluorine-based treatment, or the like can be used.

-Manufacturing method of flame-retardant adhesive tape-
The flame-retardant adhesive tape of the present embodiment is not particularly limited and can be produced, for example, by a known method. Specifically, in an adhesive tape having an adhesive layer formed on one side, a flame-retardant adhesive is applied to the surface of a release film and dried to form an adhesive layer. Then, it can be produced by adhering a base material to the surface of the pressure-sensitive adhesive layer. Further, the adhesive tape having the adhesive layer formed on both sides is dried by applying a flame-retardant adhesive to the surface of the release film, following the adhesive tape having the first adhesive layer formed on one side. This can be produced by forming a second pressure-sensitive adhesive layer and sticking a base material to which the first pressure-sensitive adhesive layer is bonded to the surface of the second pressure-sensitive adhesive layer.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

First, the measurement method and the evaluation method used in Examples and Comparative Examples will be described.
(1) Cumulative particle size distribution of ammonium polyphosphate (D95, D50)
A laser diffraction / scattering particle size distribution measuring device (Nikkiso Co., Ltd. Microtrac MT3300EX-II compatible with both water and organic solvents, measurable particle size 0.02 to 2000 μm) was used to measure the cumulative particle size distribution. Ethyl acetate was circulated in a standard sample circulator SDC, and an ammonium polyphosphate dispersion (obtained according to a production example described later) was charged to measure the particle size distribution. When the viscosity of the ammonium polyphosphate dispersion was high, it was appropriately diluted with ethyl acetate before charging.
Measurement parameters ・ Number of measurements: AVG / 2
・ Measurement time (seconds): 30
-Distribution display: Volume / particle permeability: Transmission / particle refractive index: 1.81
-Particle shape: Non-spherical-Solvent name / Refractive index: Ethyl Acate / 1.37

(2) X-ray diffraction measurement of ammonium polyphosphate Fix the obtained adhesive tape on a glass plate with the adhesive layer facing up, and X-ray diffraction charts at any three locations on the surface of the adhesive layer. The measurement was performed using a line diffractometer SmartLab (manufactured by Rigaku). For the charts obtained by measuring at each location, the peak intensity value with a diffraction angle of 2θ = 15.5 ± 0.2 ° is divided by the peak intensity value with a diffraction angle of 2θ = 14.6 ± 0.2 °. The value obtained was obtained, and the value obtained by arithmetically averaging the values was used as the X-ray diffraction peak intensity ratio.
Measurement conditions: 2θ / θ method 2θ = 1 to 70 deg.
step = 0.02 deg.
speed = 20 deg. / Min.
Analysis software: PDXL

(3) Thickness of Adhesive Layer The obtained adhesive tape was immersed in liquid nitrogen for 1 minute, and then bent and split in liquid nitrogen using tweezers to prepare a section for observing a split cross section. After returning the section to room temperature in a desiccator, fix it on the sample table so that the electron beam is perpendicular to the fractured surface, and use an electron microscope (Miniscope (registered trademark) TM3030Plus, manufactured by Hitachi High-Technology Co., Ltd.). , The fracture surface was observed. The distance from any point on the surface of the pressure-sensitive adhesive layer (the surface in contact with the release film) in the observation field to the surface of the base material was measured at 10 points in the vertical direction, and the arithmetic mean value was taken as the thickness of the pressure-sensitive adhesive layer.
In the case of double-sided tape, the thickness of the pressure-sensitive adhesive layer was determined for both sides of the tape, and a smaller value was taken as the thickness of the pressure-sensitive adhesive layer.

(4) Thickness of Adhesive Tape The thickness of the obtained adhesive tape (with the release film) was measured at 10 points at random using a constant pressure thickness gauge (Tester Sangyo Co., Ltd.). Next, the thickness of the release film was subtracted from the measured thickness, and the value obtained by arithmetic mean was taken as the thickness of the adhesive tape.

(5) UL94 VTM Combustion Test Judgment was made by a combustion test based on the VTM test described in the UL standard (UL94 "Combustion test method for plastic materials for equipment parts"). The single-sided tape was subjected to a combustion test under both conditions when the adhesive surface was on the outside and when the adhesive surface was on the inside, and the lower flame retardancy determination result was taken as the flame retardancy of the tape.

(6) 180 ° peel adhesive strength (double-sided tape)
With respect to the adhesive tape, one adhesive surface was backed with a polyester film of 25 μm, and the size thereof was set to 20 mm × 100 mm to obtain a tape sample. A stainless steel plate was placed on the other adhesive surface of the tape sample, pressure-bonded one reciprocatingly using a 2 kg roller, and then left at room temperature for 1 hour. Then, it was peeled off in the 180 ° direction at a peeling speed of 300 mm / min, and the adhesive force (N) at that time was measured.

(7) 180 ° peel adhesive strength (single-sided tape)
A stainless steel plate was placed on the adhesive surface of a tape sample having a size of 25 mm × 100 mm, pressure-bonded once reciprocating using a 2 kg roller, and then left at room temperature for 1 hour. Then, it was peeled off in the 180 ° direction at a peeling speed of 300 mm / min, and the adhesive force (N) at that time was measured.

Subsequently, each component used in Examples and Comparative Examples will be described.
(1) Adhesive component As the adhesive component, an acrylic acid ester copolymer obtained by the following method was used.
50 parts of 2-ethylhexyl acrylate, 46 parts of n-butyl acrylate, 3.5 parts of acrylic acid, 0.5 part of 2-hydroxyethyl acrylate, and a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a plucking funnel. , 0.2 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator was dissolved in 100 parts of ethyl acetate, and after substitution with nitrogen, polymerization was carried out at 80 ° C. for 8 hours. The obtained acrylic acid ester copolymer solution had a solid content of 50% and a weight average molecular weight of 400,000.

(2) Ammonium polyphosphate (APP)
(APP-1)
Ammonium polyphosphate (manufactured by CBC, TERRAJU_C-30) was used.

(APP-2)
Ammonium polyphosphate (APP-1) was blown into an elbow jet classifier (EJ-15, manufactured by Nittetsu Mining Co., Ltd.) at a blowing pressure of 0.5 MPa, with a coarse grain removal rate of 30% and a fine grain removal rate of 0%. It is ammonium polyphosphate obtained by setting the classification edge position so as to be the same and performing the classification treatment.

(APP-3)
Using an elbow jet classifier (EJ-15, manufactured by Nittetsu Mining Co., Ltd.), ammonium polyphosphate (APP-1) has a blowing pressure of 0.5 MPa, a coarse grain removal rate of 90%, and a fine grain removal rate of 0%. It is ammonium polyphosphate obtained by setting the classification edge position and classifying treatment.
The above-mentioned ammonium polyphosphate was used in the production of a pressure-sensitive adhesive after being made into an ammonium polyphosphate dispersion as described in the production example described later, and was pulverized depending on the production example.

(3) Metal Hydroxide Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., BE033) having an average particle diameter of 3 μm was used as the metal hydroxide.

(4) Aliphatic polyhydric alcohol Dipentaerythritol (Charmer DP40, manufactured by Perstop) was used as the aliphatic polyhydric alcohol.

(5) Ester form of rosin compound and aliphatic polyhydric alcohol (E-1)
Polymerized rosin pentaerythritol ester (Haritac PCJ, manufactured by Harima Chemicals, Inc.) was used.
・ (E-2)
Hydrogenated rosin methyl ester (M-HDR, manufactured by Maruzen Yuka Shoji Co., Ltd.) was used.

(6) Base material (S-1)
A non-woven fabric of rayon fiber (manufactured by Papilia Nippon Paper Industries Co., Ltd., DT-6) having a thickness of 16 μm and 6 g / m ² was used.
・ (S-2)
A polyimide film having a thickness of 12.5 μm (Kapton 50H, manufactured by Toray DuPont Co., Ltd.) was used.

(7) Hardener / Epoxy cross-linking agent (manufactured by Soken Chemical Co., Ltd., E-2XM, solid content 2%)

(8) Diluting solvent ・ Ethyl acetate (manufactured by Showa Denko KK) was used.

Subsequently, a method for producing each ammonium polyphosphate dispersion and a method for producing Examples / Comparative Examples will be described.
(Manufacturing Example 1)
150 parts by mass of APP-1 was added to 100 parts by mass of the solid content of the acrylic acid ester copolymer, and the mixture was sufficiently stirred until uniformly dispersed to obtain an ammonium polyphosphate dispersion. The particle size distribution measurement showed that D95 was 23.0 μm and D50 was 10.8 μm.

(Manufacturing Example 2)
An ammonium polyphosphate dispersion was obtained in the same manner as in Production Example 1 except that APP-1 was changed to APP-2. The particle size distribution measurement showed that D95 was 14.5 μm and D50 was 7.4 μm.

(Manufacturing Example 3)
An ammonium polyphosphate dispersion was obtained in the same manner as in Production Example 1 except that APP-1 was changed to APP-3. The particle size distribution measurement showed that D95 was 7.7 μm and D50 was 3.8 μm.

(Manufacturing Example 4)
100 parts by mass of APP-1 and 200 parts by mass of ethyl acetate were added to 100 parts by mass of the solid content of the acrylic acid ester copolymer, and the mixture was sufficiently stirred until dispersed, and then a horizontal 20 L bead mill (manufactured by Asada Iron Works Co., Ltd.). , Nanomill, φ1 mm zirconia beads, bead filling rate 70%, rotation speed 1200 rpm, discharge flow rate 3 kg / min) were passed 5 passes to obtain an ammonium polyphosphate dispersion. The particle size distribution measurement showed that D95 was 12.3 μm and D50 was 7.1 μm.

(Manufacturing Example 5)
An ammonium polyphosphate dispersion was obtained in the same manner as in Production Example 4 except that the horizontal 20L bead mill was passed 10 passes. The particle size distribution measurement showed that D95 was 8.4 μm and D50 was 4.2 μm.

(Examples 1-3, 5, 6 and Comparative Examples 1-4, 6)
Acrylic acid ester copolymer, aluminum hydroxide, dipentaerythritol, polymerized rosin pentaerythritol ester, hydrogenated rosin methyl ester, etc. were added to the ammonium polyphosphate dispersion of Production Examples 1 to 5 so as to have the compositions shown in Table 1. An epoxy-based cross-linking agent was added, and the mixture was sufficiently stirred until it became uniform to obtain a flame-retardant pressure-sensitive adhesive.
Further, after adding ethyl acetate to the obtained flame-retardant pressure-sensitive adhesive to prepare it so that the solid content becomes 30%, it is coated on a polyester release film using an applicator having a coating thickness of 65 μm, and at 85 ° C. It was heated and dried for 3 minutes to obtain a flame-retardant pressure-sensitive adhesive layer. The flame-retardant adhesive layer thus obtained was attached to both sides of the base material S-1 using a desktop laminator (manufactured by Tester Sangyo Co., Ltd.) at a feed rate of 2.0 m / s and a pressure of 0.25 MPa. By combining and then aging at 40 ° C. for 48 hours, a flame-retardant adhesive tape having an adhesive layer on both sides was obtained.
Table 1 shows the results of evaluating the obtained flame-retardant adhesive and the flame-retardant adhesive tape by the above method.
The flame-retardant adhesive tape of Comparative Example 1 was judged to have low adhesiveness because the base material did not adhere to the first adhesive layer. Further, when the UL94VTM combustion test using the adhesive tape was performed for Comparative Examples 2, 3, 4, and 6, there was a test piece that burned to the marked line by ignition, and it was out of the rank of UL94VTM.

(Example 4, Comparative Example 5)
Acrylic acid ester copolymer, aluminum hydroxide, dipentaerythritol, polymerized rosin pentaerythritol ester, hydrogenated rosin methyl ester, etc. were added to the ammonium polyphosphate dispersions of Production Examples 1 and 2 so as to have the compositions shown in Table 1. An epoxy-based cross-linking agent was added, and the mixture was sufficiently stirred until it became uniform to obtain a flame-retardant pressure-sensitive adhesive.
Further, after adding ethyl acetate to the obtained flame-retardant pressure-sensitive adhesive to prepare it so that the solid content becomes 30%, it is coated on a polyester release film using an applicator having a coating thickness of 70 μm, and at 85 ° C. It was heated and dried for 3 minutes to obtain a flame-retardant pressure-sensitive adhesive layer. The flame-retardant adhesive layer thus obtained was attached to one side of the base material S-2 using a desktop laminator (manufactured by Tester Sangyo Co., Ltd.) at a feed rate of 2.0 m / s and a pressure of 0.25 MPa. They were combined and then aged at 40 ° C. for 48 hours to obtain a flame-retardant adhesive tape having an adhesive layer on one side. Table 1 shows the results of evaluating the obtained adhesive tape by the above method.
The flame-retardant adhesive tape of Comparative Example 5 was judged to have low adhesiveness because the base material did not adhere to the first adhesive layer.

According to the present invention, a flame-retardant adhesive that can achieve both adhesiveness and flame retardancy at a high level even when used for a thinned adhesive layer of an adhesive tape, and a thinned adhesive tape. However, it is possible to provide a flame-retardant adhesive tape capable of achieving both the adhesiveness and the flame retardancy at a high level.

Claims (5)

It contains 100 parts by mass of the adhesive component and 65 parts by mass or more of ammonium polyphosphate having a particle size D95 of 20.0 μm or less of particles corresponding to a cumulative 95% from the small diameter side of the cumulative particle size distribution.
In the X-ray diffraction measurement of ammonium polyphosphate, the peak intensity value of the diffraction angle 2θ = 15.5 ± 0.2 ° is divided by the peak intensity value of the diffraction angle 2θ = 14.6 ± 0.2 °. A flame-retardant adhesive having a value of 1.4 or more. The flame-retardant pressure-sensitive adhesive according to claim 1, wherein the ammonium polyphosphate is classified. The flame-retardant pressure-sensitive adhesive according to claim 1 or 2, which contains a metal hydroxide. The flame-retardant pressure-sensitive adhesive according to any one of claims 1 to 3, which contains an aliphatic polyhydric alcohol and / or an ester of a rosin compound and an aliphatic polyhydric alcohol. A flame-retardant adhesive tape, which comprises a pressure-sensitive adhesive layer formed by the flame-retardant pressure-sensitive adhesive according to any one of claims 1 to 4 on at least one surface of a base material.