CN112930379B

CN112930379B - Flame retardant adhesives and flame retardant adhesive tapes

Info

Publication number: CN112930379B
Application number: CN201980071661.4A
Authority: CN
Inventors: 森川泰宏; 山上晃
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2018-12-25
Filing date: 2019-12-12
Publication date: 2023-10-27
Anticipated expiration: 2039-12-12
Also published as: KR102668134B1; CN112930379A; KR20210106414A; JP6743999B1; JPWO2020137573A1; WO2020137573A1

Abstract

The purpose of the present application is to provide a flame-retardant adhesive agent which can achieve both high-level adhesion and flame retardance even in the case of a flame-retardant adhesive tape for use in the film formation of an adhesive layer, and a flame-retardant adhesive tape which can achieve both high-level adhesion and flame retardance even when the adhesive layer is thinned. The flame-retardant adhesive of the present application is characterized by comprising 100 parts by mass of an adhesive component and 65 parts by mass or more of ammonium polyphosphate, wherein the ammonium polyphosphate has a particle diameter D95 of 20.0 [ mu ] m or less, which corresponds to 95% of particles accumulated from the small diameter side of the cumulative particle size distribution, and wherein the value obtained by dividing the peak intensity value of diffraction angle 2θ=15.5±0.2° by the peak intensity value of diffraction angle 2θ=14.6±0.2° in the X-ray diffraction measurement of the ammonium polyphosphate is 1.4 or more. The flame-retardant adhesive tape of the present application is characterized in that at least one surface of the base material has an adhesive layer formed of the flame-retardant adhesive.

Description

Flame-retardant adhesive and flame-retardant adhesive tape

Technical Field

The present application relates to a flame retardant adhesive and a flame retardant adhesive tape.

Background

With remarkable progress in electronic technology, high integration and high performance of electrical, electronic and OA equipment are required, and in order to reduce the risk of fire due to high temperature and heat storage in the equipment and to prevent fire, the pressure-sensitive adhesive tape used in the equipment is also required to have high flame retardancy. In addition, various studies have been made on flame retardance of plastic materials in various fields such as home appliances, vehicles, building materials, etc., and high flame retardance is required for adhesive tapes used for fixing these materials.

As the pressure-sensitive adhesive tape, a pressure-sensitive adhesive containing ammonium polyphosphate (for example, patent document 1 and the like) has been proposed, whereby high flame retardancy can be exhibited.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 11-1669

Disclosure of Invention

In recent years, for example, in the above applications, further high integration and weight reduction have been carried out, and pressure-sensitive adhesive tapes are required to have not only high flame retardancy at the UL94VTM-0 level but also thin walls. In order to thin the pressure-sensitive adhesive tape, it is necessary to thin not only the base material of the pressure-sensitive adhesive tape but also the pressure-sensitive adhesive layer. However, in the case of thinning the pressure-sensitive adhesive layer, the pressure-sensitive adhesive properties and flame retardancy of the pressure-sensitive adhesive tape are in a trade-off relationship, and it is difficult to achieve both of them in the above-mentioned conventional techniques.

Accordingly, an object of the present application is to provide a flame-retardant adhesive agent which can achieve both of high-level adhesion and flame retardance even in the case of a flame-retardant adhesive tape for use in making an adhesive layer thin, and a flame-retardant adhesive tape which can achieve both of high-level adhesion and flame retardance even in the case of thinning.

The present inventors have conducted intensive studies to solve the problems of the prior art described above, and as a result, have found the present application as a result of the following findings. That is, in order to ensure flame retardancy in the pressure-sensitive adhesive layer formed into a film, it is preferable to use type II ammonium polyphosphate in various flame retardants, but in practice, if the pressure-sensitive adhesive layer formed into a film contains type II ammonium polyphosphate, sufficient adhesiveness cannot be obtained due to large particles existing in the particles, and it is difficult to industrially produce the pressure-sensitive adhesive layer so that large particles are not generated in the particles of type II ammonium polyphosphate. In addition, the present inventors have found that: when the type II ammonium polyphosphate is used as a binder, if the particles are pulverized and thinned, for example, sufficient flame retardancy may not be ensured even if the binder is obtained, and in such a case, the type I ammonium polyphosphate having a low effect of improving flame retardancy is generated in the type II ammonium polyphosphate. In addition, the inventors have found the following: even if form I ammonium polyphosphate is produced in form II ammonium polyphosphate, it has an allowable content in terms of flame retardancy. Based on the findings described above, the present inventors have conceived that the content of type I ammonium polyphosphate that allows Xu Liang in type II ammonium polyphosphate is limited by X-ray diffraction measurement in order to ensure flame retardancy on the premise that type II ammonium polyphosphate that uses relatively fine particles is used for thinning an adhesive tape, and completed the present application.

Namely, the present application is as follows.

[ 1 ] A flame-retardant adhesive comprising 100 parts by mass of an adhesive component and 65 parts by mass or more of ammonium polyphosphate having a particle diameter D95 of 20.0 [ mu ] m or less, which corresponds to 95% of particles accumulated from the small diameter side of the cumulative particle size distribution,

in the X-ray diffraction measurement of ammonium polyphosphate, 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 1.4 or more.

The flame retardant adhesive according to the above [ 1 ], wherein the ammonium polyphosphate is obtained by classification.

The flame-retardant adhesive according to [ 1 ] or [ 2 ], wherein the flame-retardant adhesive contains a metal hydroxide.

The flame retardant adhesive according to any one of the above [ 1 ] to [ 3 ], wherein the flame retardant adhesive comprises an aliphatic polyol and/or an ester of a rosin-based compound and an aliphatic polyol.

[ 5 ] A flame-retardant adhesive tape, characterized in that at least one side of a substrate has an adhesive layer formed of the flame-retardant adhesive according to any one of [ 1 ] to [ 4 ].

According to the present application, it is possible to provide a flame-retardant adhesive agent which can achieve both of high-level adhesion and flame retardance even in the case of a flame-retardant adhesive tape for making an adhesive layer thin, and a flame-retardant adhesive tape which can achieve both of high-level adhesion and flame retardance even in the case of making an adhesive layer thin.

Detailed Description

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

Flame retardant adhesive

The flame-retardant adhesive of the present embodiment is characterized by comprising 100 parts by mass of an adhesive component and 65 parts by mass or more of ammonium polyphosphate having a particle diameter D95 of 20.0 [ mu ] m or less, which corresponds to 95% of particles accumulated from the small diameter side of the cumulative particle size distribution,

Thus, even when a flame-retardant adhesive (hereinafter, also simply referred to as "adhesive") is used as an adhesive layer of a flame-retardant adhesive tape (hereinafter, also simply referred to as "adhesive tape") having reduced thickness, both the adhesion and flame retardancy can be achieved at a high level.

Binding component-

The adhesive component of the present embodiment is not particularly limited, and examples thereof include an acrylic adhesive component, a polyurethane adhesive component, a synthetic rubber adhesive component, a natural rubber adhesive component, a silicone adhesive component, and the like. In the present embodiment, an acrylic pressure-sensitive adhesive component is preferable from the viewpoint of easily obtaining a strong pressure-sensitive adhesive force.

The acrylic pressure-sensitive adhesive component is not particularly limited, and contains, for example, at least 1 acrylic polymer containing an alkyl (meth) acrylate monomer as a monomer unit. Examples of the alkyl (meth) acrylate monomer include, but are not particularly limited to, alkyl (meth) acrylates having an alkyl group with 2 to 14 carbon atoms, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, isoamyl acrylate, hexyl acrylate, octyl acrylate, isononyl acrylate, isodecyl acrylate, butyl methacrylate, hexyl methacrylate, isodecyl methacrylate, and lauryl methacrylate.

In the present specification, "alkyl (meth) acrylate" means alkyl acrylate or alkyl methacrylate.

The acrylic polymer may be copolymerized with monomers having a carboxyl group, a hydroxyl group, or the like, such as acrylic acid, maleic anhydride, and 2-hydroxyethyl (meth) acrylate. Thus, the structural unit derived from the monomer becomes a crosslinking point in the acrylic polymer, and the hardness of the adhesive component can be adjusted to exhibit a target adhesive force.

The acrylic polymer is not particularly limited, and for example, vinyl acetate, acrylonitrile, acrylamide, styrene, etc. may be copolymerized, for example, the cohesive force of the acrylic polymer may be adjusted.

The acrylic polymer is not particularly limited, and polymerization can be performed using a radical polymerization method, for example, solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization, or the like. As the polymerization initiator, there may be used organic peroxides such as benzoyl peroxide, lauroyl peroxide and bis (4-t-butylcyclohexyl) peroxydicarbonate, azo-based polymerization initiators such as 2,2 '-azobisisobutyronitrile, 2' -azobis (2-methylbutyronitrile), dimethyl-2, 2-azobis (2-methylpropionate), 4 '-azobis (4-cyanovaleric acid), dimethyl 2,2' -azobis (2-methylpropionate) and azobis (2, 4-dimethylvaleronitrile) (AVN).

The acrylic polymer contains a crosslinkable crosslinking agent to crosslink the acrylic polymer. Examples of the crosslinking agent include epoxy crosslinking agents, and polyisocyanate compounds such as aliphatic diisocyanates, aromatic diisocyanates, and aromatic triisocyanates. Further, a crosslinking accelerator containing an organometallic compound or the like may be added to the acrylic polymer having a slow crosslinking reaction. By crosslinking the acrylic polymer, the cohesive force can be improved.

Ammonium polyphosphate (APP)

The flame retardant adhesive of the present embodiment contains a specific ammonium polyphosphate. Thus, even the pressure-sensitive adhesive tape obtained by thinning the pressure-sensitive adhesive layer can ensure flame retardancy.

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, based on 100 parts by mass of the adhesive component. By setting the content to 65 parts by mass or more, desired flame retardancy can be ensured. The upper limit of the content is not particularly limited from the viewpoint of obtaining flame retardancy, and if the content is excessively increased with respect to the adhesive component, the particles may be exposed on the surface of the adhesive layer at the time of producing the adhesive tape to cause a decrease in adhesive strength, and thus 300 parts by mass or less, more preferably 200 parts by mass or less, and still more preferably 150 parts by mass or less are preferable.

In the present specification, the reference content of each component (for example, the binder component) is based on the nonvolatile component (solid component).

The particle diameter D95 of the ammonium polyphosphate particles, which corresponds to 95% of the particles accumulated 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 diameter D95 to 20.0 μm or less, the particles having a large particle diameter are reduced, and therefore the spacer effect caused by the large particles is suppressed, and the adhesive tape obtained by thinning the adhesive layer can ensure adhesion.

The lower limit of the particle diameter D95 is not particularly limited from the viewpoint of ensuring the adhesion, but if the particle diameter D95 is too low, the specific surface area increases after the formation of fine powder, and thus dispersion failure and coating failure due to thickening of the adhesive may occur, and thus it is preferably 0.1 μm or more, more preferably 1.0 μm or more, and even more preferably 3.0 μm or more.

The particle diameter D50 of the ammonium polyphosphate, which corresponds to 50% of particles accumulated 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, and even more preferably 7.5 μm or less. By setting the particle diameter D50 to 10.0 μm or less, the adhesive tape obtained by thinning the adhesive layer can sufficiently secure adhesion.

The particle diameters (D95, D50, etc.) corresponding to the particles having a predetermined proportion accumulated from the small diameter side of the cumulative particle size distribution can be measured by the method described in examples described later.

In the present embodiment, from the viewpoint of further securing the adhesiveness, the particles of ammonium polyphosphate having a particle diameter of 20 μm or more are preferably 1 mass% or less, more preferably 0.1 mass% or less, and even more preferably not included in the nonvolatile component of the flame-retardant adhesive.

In the X-ray diffraction measurement, the ammonium polyphosphate has a value of 1.4 or more 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°. The peak appearing at the diffraction angle 2θ=15.5±0.2° of ammonium polyphosphate is a peak which is characteristic of the type II ammonium polyphosphate, and the peak at the diffraction angle 2θ=14.6±0.2° is a peak which is characteristic of the type I or type II ammonium polyphosphate. That is, in the present application, by defining the relation between the peak intensity values, the content of the type I ammonium polyphosphate having a low allowable contribution to flame retardancy is defined on the premise that the ammonium polyphosphate contains the type II ammonium polyphosphate. Therefore, in the present embodiment, by setting the ratio of the peaks to the above-described relationship, the content of the type I ammonium polyphosphate present in the type II ammonium polyphosphate can be suppressed, and therefore, even in the adhesive tape obtained by thinning the adhesive layer, flame retardancy can be ensured.

In the present embodiment, from the same point of view, 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 preferably 1.5 or more, more preferably 1.6 or more, and still more preferably 2.0 or more.

In the present embodiment, from the above point of view, the larger 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°, the higher the value is, the more preferably the upper limit value is, and the value may be set to 2.8 or less. As described above, in industrial production, the type II ammonium polyphosphate particles may contain particles having a large particle diameter, but in the production process, the type II ammonium polyphosphate particles have a large particle diameter, and crystals tend to grow, in other words, the content of the type II ammonium polyphosphate in the large particles tends to be high. In addition, in the process of satisfying the above-described limit range of the particle diameter D95, there is a tendency that the larger particles are reduced, and in the case of reduction, there is a tendency that 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 2.8 or less.

The peak intensity value of the diffraction angle 2θ defined in the X-ray diffraction measurement can be measured by the method described in examples described later.

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

In the present embodiment, when ammonium polyphosphate satisfies the relationship between the defined particle diameter and the peak intensity value in the X-ray diffraction measurement, the ammonium polyphosphate II particles produced by a known method can be obtained by pulverizing and classifying the ammonium polyphosphate II particles. Specifically, the method of pulverization is not particularly limited, and a medium type dispersing machine/pulverizer such as a bead mill, a ball mill, an attritor, a planetary mill, and a vibration mill, a mortar mill, and a non-medium type dispersing machine/pulverizer typified by a jet mill may be used. As the pulverizing method, both wet and dry pulverizing methods can be used, but wet pulverizing is preferable from the viewpoints of dispersibility after pulverization, recovery of pulverized products, and ease of handling. The material of the medium in the case of using the medium type dispersing machine/pulverizer is not particularly limited, and steel, glass, alumina, zirconia, silicon nitride, or the like can be used. The diameter of the medium is not particularly limited, but from the viewpoint of suppressing the decrease in form II ammonium polyphosphate due to excessive crushing and efficiently atomizing, the diameter of the medium to be used is preferably 5mm or less, more preferably 3mm or less, and even more preferably 1mm or less. The pulverization is preferably performed under stable 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, in the case of dry classification from the viewpoint of precision control classification points, a forced vortex classifier (manufactured by Aerofine Classifier, nisshin Engineering; micron separator, manufactured by Hosokawa Micron, turbo, manufactured by Hosokawa Micron, etc.) or an inertial force field classifier (Elbo jet mill, manufactured by limonite, manufactured by Cliffis, hosokawa Micron) utilizing the coanda effect may be used.

In the classification, a flame retardant auxiliary agent, or the like other than ammonium polyphosphate may be contained, or they may be dispersed in an arbitrary dispersion medium and then wet-classified.

In this embodiment, ammonium polyphosphate can appropriately satisfy a specific relationship between a specific particle diameter and a peak intensity value in X-ray diffraction measurement, and thus ammonium polyphosphate obtained by fractionation is preferably used.

Metal hydroxide-

The flame retardant adhesive of the present embodiment may 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 60 parts by mass or more, based on 100 parts by mass of the adhesive component. By setting the content to 0.1 part by mass or more, flame retardancy can be further improved.

From the viewpoint of improving flame retardancy, the content is not particularly limited, and if the content is excessively increased with respect to the adhesive component, the particles may be exposed on the surface of the adhesive layer at the time of producing the adhesive tape, and the adhesive force may be reduced, so that it 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.

The metal hydroxide is not particularly limited, and examples thereof include magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, zinc hydroxide, copper hydroxide, vanadium hydroxide, tin hydroxide, and the like. Among them, aluminum hydroxide is preferable because moisture can be separated at a relatively low temperature, thereby exhibiting high flame retardancy.

It should be noted that 1 or 2 or more kinds of metal hydroxide may be used.

In order to improve dispersibility in the adhesive component, the metal hydroxide may be subjected to a surface treatment such as a coupling treatment or a stearic acid treatment. The particle diameter D95 of the component that can exist in a solid form in the binder such as a metal hydroxide and an aliphatic polyol described later is preferably 20.0 μm or less. Examples of the shape of the metal hydroxide include spherical, needle-like, and flake-like.

Aliphatic polyols

The flame retardant adhesive of the present embodiment may contain an aliphatic polyol. Thus, the flame retardant effect of ammonium polyphosphate can be improved, and even the flame retardance of the adhesive can be improved.

The content of the aliphatic polyol is preferably 5.0 parts by mass or more, more preferably 10.0 parts by mass or more, still more preferably 15.0 parts by mass or more, and particularly preferably 16.0 parts by mass or more, based on 100 parts by mass of the adhesive component. By setting the content to 5.0 parts by mass or more, flame retardancy can be further improved.

The content is not particularly limited from the viewpoint of improving flame retardancy. However, since the aliphatic polyol is allowed to coexist with ammonium polyphosphate to improve flame retardancy, the excessive component may become a combustible component, and thus is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 30 parts by mass or less, per 100 parts by mass of ammonium polyphosphate.

The aliphatic polyol is not particularly limited, and specific examples of the aliphatic polyol include ethylene glycol, glycerin, pentaerythritol, dipentaerythritol, tripentaerythritol, polyglycerol (triglycerol to hexaglycerol), ditrimethylolpropane, xylitol, sorbitol, mannitol, and the like. Among them, dipentaerythritol is preferable because it has high bleeding resistance to water and can form a carbonized layer with ammonium polyphosphate with high efficiency.

The aliphatic polyol may be used in an amount of 1 or 2 or more.

Esters of rosin-based compounds with aliphatic polyols

The flame retardant adhesive of the present embodiment may contain an ester of a rosin-based compound and an aliphatic polyol. Thus, the adhesiveness can be further imparted, and the flame-retardant effect by ammonium polyphosphate can also be improved, even the flame retardancy of the adhesive.

The content of the ester of the rosin compound and the aliphatic polyol is preferably 0.1 part by mass or more, more preferably 10.0 parts by mass or more, and still more preferably 20.0 parts by mass or more, based on 100 parts by mass of the adhesive component. By setting the content to 0.1 part by mass or more, flame retardancy can be further improved.

The content is not particularly limited, but is preferably 100 parts by mass or less, more preferably 70.0 parts by mass or less, and still more preferably 50.0 parts by mass or less, from the viewpoint of improving flame retardancy.

Examples of the rosin-based compound which is an ester of the rosin-based compound and an aliphatic polyhydric alcohol include rosin monomers, disproportionated rosin, polymerized rosin, hydrogenated rosin, and partially disproportionated rosin. Further, the aliphatic polyol is exemplified by the above aliphatic polyols, and among them, diethylene glycol, glycerin, pentaerythritol and the like are preferable, and pentaerythritol is more preferable. The rosin compound and the aliphatic polyol may be used in an amount of 1 or 2 or more.

Other ingredients-

The flame retardant adhesive of the present embodiment may contain a melamine derivative such as melamine cyanurate in a range that does not impair the adhesive performance, and thus the flame retardancy may be further improved or the content of ammonium polyphosphate may be reduced.

In addition, the adhesion to a nonpolar adherend can be improved by containing the tackifying resin in a range that does not reduce the required flame retardancy. Examples of the resins include terpene resins, terpene phenolic resins, rosin resins, petroleum resins, coumarone-indene resins, and phenolic resins. The shape may be a solid or a viscous liquid at ordinary temperature, and the types of the compounds may be used alone or in combination of 2 or more.

Properties of flame retardant adhesive

The flame-retardant adhesive of the present embodiment is preferably used for one of a test piece having an adhesive layer of 20 μm on one side of a base material (thickness: 12.5 μm, manufactured by Kapton 50H-Todupont Co., ltd.) and a test piece having an adhesive layer of 20 μm on both sides of a base material (thickness: 16 μm, manufactured by rayon nonwoven fabric (manufactured by DT-6 PAPAPAPIA Japan Co., ltd.) and has flame retardancy measured in accordance with the VTM test described in the UL94 standard of UL94VTM-0 or more.

The flame retardant adhesive of the present embodiment preferably has a thickness of 16. Mu.m, and a 180 DEG peel adhesion of 5N or more when an adhesive layer having a thickness of 20 μm is formed on both sides of a rayon nonwoven fabric (DT-6 PAPAPIA Japanese paper Co., ltd.). The peel adhesion can be performed by the method described in examples described below.

The viscosity of the flame-retardant adhesive according to the present embodiment is preferably 2000mpa·s or less, as measured by a B-type viscometer, on a solution prepared by diluting with ethyl acetate so that the solid content becomes 30%.

Method for producing flame-retardant adhesive

The flame-retardant adhesive of the present embodiment is not particularly limited, and can be produced by, for example, adding specific ammonium polyphosphate to the adhesive component, optionally adding a metal hydroxide, and the like, and stirring and dispersing the mixture by a high-speed dispersing machine.

Flame-retardant adhesive tape

The flame-retardant adhesive tape according to the present embodiment is characterized in that at least one surface of the base material has an adhesive layer formed of the flame-retardant adhesive according to the above embodiment of the present application. Thus, even when the pressure-sensitive adhesive layer is made thin, both the pressure-sensitive adhesive property and the flame retardancy can be achieved at a high level.

The base material of the flame-retardant adhesive tape of the present embodiment is not particularly limited, and examples thereof include a resin sheet, a nonwoven fabric, paper, a metal foil, a woven fabric, a rubber sheet, a foam sheet, a laminate thereof (particularly a laminate including a resin sheet), 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, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene Sulfide (PPs), a fluorine-based resin, polyether ether ketone (PEEK), and the like. The nonwoven fabric may be a nonwoven fabric of natural fibers (cellulose fibers); nonwoven fabrics of synthetic resin fibers such as polypropylene resin fibers, polyethylene resin fibers and polyester resin fibers. Examples of the metal foil include copper foil, stainless steel foil, and aluminum foil. Examples of the paper include japanese paper and kraft paper.

As the substrate, a substrate subjected to a treatment such as non-combustibility or self-extinguishing property can be used.

The flame-retardant adhesive tape of the present embodiment is provided with an adhesive layer formed of the above-mentioned flame-retardant adhesive, and the thickness of the adhesive layer of the flame-retardant adhesive tape can be set to 20.0 μm or less, preferably 18.0 μm or less, and more preferably 13.0 μm or less. In the case of the pressure-sensitive adhesive layer having the above thickness, it is not preferable to use the conventional pressure-sensitive adhesive tape because it is difficult to achieve both the pressure-sensitive adhesive property and the flame retardancy, but the flame-retardant pressure-sensitive adhesive tape of the present embodiment can be suitably produced even when the pressure-sensitive adhesive layer has the above thickness.

In the case where the adhesive layer is provided on one side of the substrate, the flame-retardant adhesive tape of the present embodiment may have a total thickness of 30.0 μm or less, preferably 25.0 μm or less, and more preferably 20.0 μm or less. In the case where the adhesive layer is provided on both sides of the substrate, the total thickness of the substrate and the adhesive layer may be 50.0 μm or less, preferably 40.0 μm or less, and more preferably 30.0 μm or less.

In order to protect the adhesive layer, a release film may be laminated on the flame-retardant adhesive tape of the present embodiment. The release film is not particularly limited, and for example, a release film obtained by subjecting at least one surface or both surfaces of a substrate such as a synthetic resin film such as polyethylene, polypropylene, or polyester film, paper, nonwoven fabric, cloth, foam sheet, or metal foil, or a laminate thereof, to a silicone-based treatment, a long-chain alkyl-based treatment, a fluorine-based treatment, or the like for improving the releasability from an adhesive agent can be used.

Method for producing flame-retardant adhesive tape

The flame retardant adhesive tape according to the present embodiment is not particularly limited, and can be produced by a known method, for example. Specifically, the pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed on one surface is formed by applying a flame-retardant pressure-sensitive adhesive to the surface of a release film, and drying the pressure-sensitive adhesive. Then, a substrate is bonded to the surface of the adhesive layer, whereby the adhesive layer can be produced. The pressure-sensitive adhesive tape having pressure-sensitive adhesive layers formed on both sides thereof can be produced by the following method: the adhesive tape having the 1 st adhesive layer formed on one surface is contacted with an adhesive tape, and the 2 nd adhesive layer is formed by applying a flame-retardant adhesive to the surface of the release film, drying the same, and the like, wherein the 2 nd adhesive layer has a substrate bonded to the surface thereof and the 1 st adhesive layer is bonded to the substrate.

[ example ]

Hereinafter, the present application will be further specifically described based on examples, but the present application is not limited by these examples.

First, a measurement method and an evaluation method used in examples and comparative examples will be described.

(1) Cumulative particle size distribution of ammonium polyphosphate (D95, D50)

The cumulative particle size distribution was measured using a laser diffraction/scattering particle size distribution measuring apparatus (Microtrac MT3300EX-II aqueous/organic solvent available from Nikko corporation, both of which correspond to each other, and the particle size was 0.02 to 2000 μm). Ethyl acetate was circulated through a standard sample circulator SDC, and an ammonium polyphosphate dispersion (obtained by a production example described below) was charged into the sample circulator SDC to measure the particle size distribution. When the viscosity of the ammonium polyphosphate dispersion is high, the ammonium polyphosphate dispersion is diluted with ethyl acetate and then added thereto.

Measuring parameters

Number of measurements: AVG/2

Measurement time (seconds): 30

Distribution display: volume of

Particle permeability: through the transmission of

Refractive index of particles: 1.81

Particle shape: non-spherical shape

Solvent name/refractive index: ethyl Acetate/1.37

(2) X-ray diffraction measurement of ammonium polyphosphate

The adhesive layer of the obtained adhesive tape was fixed upward on a glass plate, and a wide-angle X-ray diffraction pattern was measured at any 3 positions on the surface of the adhesive layer using an X-ray diffraction apparatus SmartLab (manufactured by Rigaku). For the graphs obtained by measurement at the respective positions, a 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° was obtained, and the obtained value was arithmetically averaged to obtain an X-ray diffraction peak intensity ratio.

Measurement conditions: 2θ/θ method 2θ=1 to 70deg.

step＝0.02deg.

speed＝20deg./min.

Analysis software: PDXL

(3) Thickness of adhesive layer

After immersing the obtained adhesive tape in liquid nitrogen for 1 minute, the adhesive tape was bent and cut in liquid nitrogen using tweezers, and a slice for observing a cut surface was produced. After the cut piece was returned to normal temperature in the dryer, the cut piece was fixed to a sample stage so that an electron beam was perpendicularly incident on the cut piece, and the cut piece was observed by using an electron microscope (manufactured by Hitachi High-Technologies, miniscope (registered trademark) TM3030 Plus). For 10 positions, 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 substrate in the vertical direction was measured, and the arithmetic average value was used as the thickness of the pressure-sensitive adhesive layer.

In the case of the double-sided tape, the thickness of the pressure-sensitive adhesive layer was obtained on both sides of the tape, and a smaller value was used as the thickness of the pressure-sensitive adhesive layer.

(4) Thickness of adhesive tape

The thickness of the obtained adhesive tape (in the state of having a release film) was measured at random for 10 positions using a constant pressure thickness gauge (test industry Co., ltd.). Next, the thickness of the release film was subtracted from the measured thickness, and arithmetic average was performed, and the obtained value was used as the thickness of the adhesive tape.

(5) UL94VTM burn test

The determination is made by a combustion test according to the VTM test described in UL standard (UL 94 "combustion test method of plastic materials for parts of equipment"). The single-sided tape was subjected to a combustion test under both conditions of the case where the adhesive surface was on the outside and the case where the adhesive surface was on the inside, and the low flame retardancy was determined as the flame retardancy of the tape.

(6) 180 degree peel adhesion (double sided tape)

For the adhesive tape, one side adhesive surface was backed with a polyester film of 25 μm, and the size thereof was set to 20mm×100mm, to obtain a tape sample. A stainless steel plate was placed on the other side of the tape sample, and the tape was attached by reciprocal pressing with a 2kg roller for 1 time, and then left at room temperature for 1 hour. Then, the film was peeled in a 180℃direction at a peeling speed of 300mm/min, and the adhesive force (N) was measured.

(7) 180 degree peel adhesion (Single sided tape)

A stainless steel plate was placed on the adhesive surface of the tape sample having a size of 25mm X100 mm, and the tape sample was attached by reciprocal pressing using a 2kg roller 1 time, followed by being placed at room temperature for 1 hour. Then, the film was peeled in a 180℃direction at a peeling speed of 300mm/min, and the adhesive force (N) was measured.

Next, the components used in examples and comparative examples will be described.

(1) Adhesive component

As the adhesive component, an acrylate copolymer obtained by the following method was used.

In a reaction vessel equipped with a condenser, a stirrer, a thermometer and a dropping funnel, 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 0.2 part of 2,2' -azobisisobutyronitrile as a polymerization initiator were dissolved in 100 parts of ethyl acetate, and after nitrogen substitution, polymerization was carried out at 80℃for 8 hours. The solid content of the obtained acrylic copolymer solution was 50%, and the weight average molecular weight was 40 ten thousand.

(2) Ammonium polyphosphate (APP)

(APP-1)

Ammonium polyphosphate (manufactured by CBC Co., ltd., TERRAJU-C-30) was used.

(APP-2)

The ammonium polyphosphate was obtained by classifying ammonium polyphosphate (APP-1) using an elbow jet classifier (EJ-15, manufactured by Nissin Co., ltd.) under a blowing pressure of 0.5MPa, with the classification edge position set so that the coarse particle removal rate became 30% and the fine particle removal rate became 0%.

(APP-3)

The ammonium polyphosphate was obtained by classifying ammonium polyphosphate (APP-1) using an elbow jet classifier (EJ-15, manufactured by Nissin iron Co., ltd.) under a blowing pressure of 0.5MPa, with the classification edge position set so that the coarse particle removal rate became 90% and the fine particle removal rate became 0%.

The ammonium polyphosphate was used for the production of a binder after the preparation of an ammonium polyphosphate dispersion, and was subjected to a pulverization treatment according to the production example, as described in the production example described below.

(3) Metal hydroxide

Aluminum hydroxide (BE 033, manufactured by Nippon light metals Co., ltd.) having an average particle diameter of 3 μm was used as the metal hydroxide.

(4) Aliphatic polyols

Dipentaerythritol (manufactured by Perstorp corporation, charmerDP 40) was used as the aliphatic polyol.

(5) Esters of rosin-based compounds and aliphatic polyols

·(E-1)

Pentaerythritol esters of polymerized rosin (Harima chemical Co., ltd., haritac PCJ) were used.

·(E-2)

Hydrogenated rosin methyl ester (manufactured by Wan oil Co., ltd., M-HDR) was used.

(6) Substrate material

·(S-1)

Using a thickness of 16 μm, 6g/m ² Is a nonwoven fabric of rayon fibers (manufactured by PAPAPAPAPIA Japanese paper Co., ltd., DT-6).

·(S-2)

Polyimide film (Kapton 50H, manufactured by dolon, eastern) having a thickness of 12.5 μm was used.

(7) Curing agent

Epoxy-based crosslinking agent (E-2 XM, solid content 2%) manufactured by Zodiac chemical Co., ltd

(8) Dilution solvent

Ethyl acetate (manufactured by sho and electric company).

Next, a method for producing each ammonium polyphosphate dispersion and a method for producing examples and comparative examples will be described.

Production example 1

150 parts by mass of APP-1 was added to 100 parts by mass of the solid content of the acrylate copolymer, and the mixture was sufficiently stirred until the mixture was uniformly dispersed, to obtain an ammonium polyphosphate dispersion. The D95 was 23.0 μm and the D50 was 10.8 μm as determined on the basis of the particle size distribution.

Production 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 D95 was 14.5 μm and the D50 was 7.4 μm as determined on the basis of the particle size distribution.

Production 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 D95 was 7.7 μm and the D50 was 3.8 μm as determined on the basis of the particle size distribution.

Production 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 acrylate copolymer, and the mixture was sufficiently stirred and dispersed, followed by 5 times passing through a horizontal 20L bead mill (manufactured by shallow Tian Tiegong Co., ltd., nanomill, bead packing ratio of 70% by using zirconium oxide having a diameter of 1mm, rotation speed of 1200rpm, and discharge flow rate of 3 kg/min), to obtain an ammonium polyphosphate dispersion. The D95 was 12.3 μm and the D50 was 7.1 μm as determined on the basis of the particle size distribution.

Production example 5

An ammonium polyphosphate dispersion was obtained in the same manner as in production example 4 except that the dispersion was passed through a horizontal 20L bead mill 10 times. The D95 was 8.4 μm and the D50 was 4.2 μm as determined on the basis of the particle size distribution.

Examples 1 to 3, 5 and 6 and comparative examples 1 to 4 and 6

The acrylic acid ester copolymer, aluminum hydroxide, dipentaerythritol, pentaerythritol ester of polymerized rosin, methyl ester of hydrogenated rosin, and epoxy-based crosslinking agent were added to the ammonium polyphosphate dispersions of production examples 1 to 5 so as to have the compositions shown in table 1, and the mixture was sufficiently stirred until uniform, to obtain a flame-retardant adhesive.

Ethyl acetate was added to the obtained flame-retardant adhesive, and the mixture was prepared so that the solid content became 30%, and then, the mixture was applied to a polyester release film using an applicator having a coating thickness of 65 μm, and the film was dried by heating at 85 ℃ for 3 minutes, thereby obtaining a flame-retardant adhesive layer. The thus obtained flame-retardant adhesive layer was bonded to both sides of the substrate S-1 using a bench laminator (manufactured by TESTER INDUSTRIAL Co., ltd.) at a conveying speed of 2.0m/S and a pressure of 0.25MPa, and then cured at 40℃for 48 hours, whereby a flame-retardant adhesive tape having adhesive layers on both sides was obtained.

The results of evaluating the obtained flame-retardant adhesive and flame-retardant adhesive tape by the above method are shown in table 1.

The flame-retardant adhesive tape of comparative example 1 was judged to have low adhesion since the base material was not attached to the adhesive layer of layer 1. In comparative examples 2, 3, 4 and 6, UL94VTM burning test using an adhesive tape was performed, and as a result, test pieces that burned to a marked line due to fire were provided, and the test pieces were outside the UL94VTM rating.

Example 4, comparative example 5

The acrylic acid ester copolymer, aluminum hydroxide, dipentaerythritol, pentaerythritol ester of polymerized rosin, methyl ester of hydrogenated rosin, and epoxy-based crosslinking agent were added to the ammonium polyphosphate dispersions of production examples 1 and 2 so as to have the compositions shown in table 1, and the mixture was sufficiently stirred until uniform, to obtain a flame-retardant adhesive.

Ethyl acetate was added to the obtained flame-retardant adhesive, and the mixture was prepared so that the solid content became 30%, and then, the mixture was applied to a polyester release film using an applicator having a coating thickness of 70 μm, and the film was dried by heating at 85 ℃ for 3 minutes, to obtain a flame-retardant adhesive layer. The thus obtained flame-retardant adhesive layer was bonded to one side of the substrate S-2 using a bench laminator (manufactured by TESTER INDUSTRIAL Co., ltd.) at a conveying speed of 2.0m/S and a pressure of 0.25MPa, followed by curing at 40℃for 48 hours, whereby a flame-retardant adhesive tape having an adhesive layer on one side was obtained. The results of evaluating the obtained adhesive tape by the above method are shown in table 1.

The flame-retardant adhesive tape of comparative example 5 was judged to have low adhesion since the base material was not attached to the adhesive layer of layer 1.

[ Table 1 ]

Industrial applicability

According to the present application, it is possible to provide a flame-retardant adhesive agent which can achieve both of the adhesion and flame retardance thereof at a high level even when used for an adhesive layer obtained by thinning an adhesive tape, and a flame-retardant adhesive tape which can achieve both of the adhesion and flame retardance thereof at a high level even if thinned.

Claims

1. A flame-retardant adhesive comprising 100 parts by mass of an adhesive component and 65 to 150 parts by mass of ammonium polyphosphate,

the particle diameter D95 of the ammonium polyphosphate particles corresponding to 95% of the particles accumulated from the small diameter side of the cumulative particle size distribution is 20.0 μm or less, the particle diameter D50 of the ammonium polyphosphate particles corresponding to 50% of the particles accumulated from the small diameter side of the cumulative particle size distribution is 10.0 μm or less,

2. The flame retardant adhesive of claim 1, wherein the ammonium polyphosphate is fractionated.

3. The flame retardant adhesive according to claim 1 or 2, wherein the flame retardant adhesive contains a metal hydroxide.

4. The flame retardant adhesive according to claim 1 or 2, wherein the flame retardant adhesive contains an aliphatic polyol, and/or an ester of a rosin-based compound and an aliphatic polyol.

5. The flame-retardant adhesive according to claim 1 or 2, wherein a value obtained by dividing a peak intensity value of diffraction angle 2θ=15.5±0.2° by a peak intensity value of diffraction angle 2θ=14.6±0.2° in an X-ray diffraction measurement of the ammonium polyphosphate is 2.8 or less.

6. A flame-retardant adhesive tape comprising a substrate and an adhesive layer formed of the flame-retardant adhesive according to any one of claims 1 to 5 on at least one side of the substrate.