JP6911685B2 - Hot melt type flame-retardant adhesive and protective sheet with flame-retardant adhesive - Google Patents

Description

The present invention relates to a hot melt type flame-retardant adhesive. Specifically, it is a hot melt type that can be applied in a heat-melted state or a heat-softened state at the time of coating, and can form an adhesive sheet that can be attached to an adherend without requiring heating at the time of use, that is, at the time of application. Regarding the agent. Furthermore, the present invention relates to a pressure-sensitive adhesive sheet using the hot-melt type flame-retardant pressure-sensitive adhesive.

A simple head cover such as a non-woven fabric that can be easily attached and detached may be attached to the head of a seat such as an airplane, a train such as a Shinkansen, or a bus. Examples of the mounting method include the use of a hook-and-loop fastener and a string, as well as the use of a heat-weldable hot melt (Patent Documents 1 and 2).

In addition, in so-called open kitchens such as food supermarkets and restaurants, a partition may be provided between the kitchen and the sales floor / hall, and a simple protective (antifouling) sheet may be used to prevent the partition from becoming dirty. be. As a mounting method, the use of an adhesive can be mentioned (Patent Document 3).

Patent Document 4 discloses a flame-retardant conductive fabric in which a hot-melt resin adhesive layer containing a flame retardant is formed on one surface of the fabric composed of conductive organic fibers.
Patent Document 5 discloses a hot melt-based sealing material containing a synthetic rubber, a tackifier resin, a liquid resin, a flame retardant, and the like.
Further, Patent Document 6 describes a hot-melt adhesive containing a phosphorus-based compound that is liquid at 180 ° C., and describes that it is suitable for use as an electromagnetic wave shielding material.

Japanese Unexamined Patent Publication No. 02-21110 Registered Utility Model No. 3057949 Japanese Unexamined Patent Publication No. 2015-063602 Japanese Unexamined Patent Publication No. 2004-21247 Japanese Patent Application Laid-Open No. 2007-099800 JP-A-2010-084002

In recent years, in addition to mechanical parts and electrical system parts that make up trains and buses such as airplanes and bullet trains, interior materials are also required to be flame-retardant, and the demand is for head covers and backrests that are frequently replaced with new ones. It is also expanding to covers and seat covers. In addition, various covers (bed covers, pillowcases, disposable lab coats, etc.) that are used for medical examinations and treatments in hospitals and long-term care facilities and are discarded may also be required to be flame-retardant in the future. be.
Flame-retardant is also required for the protective (antifouling) sheet used as a partition between the kitchen and the sales floor / dining room.
Further, flame-retardant adhesives for attaching these head covers and the like and protective (antifouling) sheets to the headrest surface, the backrest surface, the seat surface, the partition member of the kitchen and the like have come to be required.

However, Patent Documents 1 to 3 do not disclose or suggest the problem of flame retardancy.
On the other hand, Patent Documents 4 to 6 disclose the use of flame retardants.
However, the hot melt resin adhesive layer specifically disclosed in Patent Document 4 is attached by utilizing heat (paragraph 41). Further, although Patent Document 5 discloses the use of a tackifier resin, it is understood that the sealing material described in Patent Document 5 is adhered to an adherend by using heat (paragraph 31).
Further, the surface of the article coated with the hot melt adhesive described in Patent Document 6 does not have adhesiveness, and heat is used when the article is attached to the adherend (paragraphs 75 and 76). ).
That is, Patent Documents 4 to 6 do not disclose or suggest any adhesive for forming an adhesive sheet that does not require heating at the time of attachment and can be attached to an adherend.

The present invention provides a flame-retardant adhesive for forming an adhesive sheet that can be attached to an adherend represented by a headrest surface, a backrest surface, a seat surface, a partition member of a kitchen, or the like without heating. The purpose is. Another object of the present invention is to provide a flame-retardant adhesive sheet that can be attached to an adherend without heating.

As a result of diligent studies to solve the above problems, the present inventor has obtained a phosphorus-based flame retardant and a surfactant that are liquid at 23 ° C. with respect to a block copolymer of an alkyl methacrylate ester and an alkyl acrylic acid ester. Alternatively, it has been found that a hot melt type flame retardant adhesive can be obtained by using a tackifier.
That is, the present invention relates to the following [1] to [8].
[1] In the total of 100% by mass of the following (A) to (D),
Block copolymer (A) of a methacrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms and an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (A) 35 to 75% by mass, phosphorus liquid at 23 ° C. A hot melt type flame retardant pressure-sensitive adhesive containing 10 to 50% by mass of a flame retardant (B), 1 to 15% by mass of a surfactant (C), and 0 to 30% by mass of a tackifier resin (D).

[2] The mass ratio of the methacrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group to the acrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group is the methacrylic acid alkyl ester: the acrylic acid alkyl ester = The hot melt type flame-retardant pressure-sensitive adhesive according to [1], which is 10 to 40: 90 to 60.

[3] The hot-melt type flame-retardant adhesive according to [1] or [2], wherein the melt flow rate of the block copolymer (A) at 190 ° C. and 2.16 kgf / cm ^{2 is 1 to 320 g / 10 minutes.} Agent.

[4] The block copolymer (A) is a block copolymer of methyl methacrylate and n-butyl acrylate, or a block copolymer of methyl methacrylate and 2-ethylhexyl acrylate, [1]. -[3] The hot melt type flame-retardant adhesive according to any one of

[5] The hot-melt type flame retardant according to any one of [1] to [4], wherein the surfactant (C) is a cationic, nonionic, anionic, or amphoteric surfactant. Sex adhesive.

[6] The hot-melt type flame-retardant adhesive according to [5], wherein the surfactant (C) is a nonionic surfactant.

[7] A flame-retardant pressure-sensitive adhesive portion formed from the hot-melt type flame-retardant pressure-sensitive adhesive according to any one of [1] to [6] is supported on at least a part of one surface of the sheet-like base material. Protective sheet with flame-retardant adhesive.

[8] The hot-melt type flame-retardant adhesive according to any one of [1] to [6] is melted and applied to at least a part of one surface of the sheet-like substrate to form a flame-retardant adhesive portion. A method for manufacturing a protective sheet with a flame-retardant adhesive, which comprises providing.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a flame-retardant adhesive for forming an adhesive sheet that can be attached to an adherend represented by a headrest surface, a backrest surface, a seat surface, a partition member of a kitchen, or the like without heating. It became so. Further, according to the present invention, it has become possible to provide a flame-retardant adhesive sheet that can be attached to an adherend without heating.

<Block copolymer (A) of a methacrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms and an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms>
The block copolymer (A) of a methacrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms and an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms used in the present invention has the following block co-weight. It may also be called coalescence (A).
The block copolymer (A), a hard segment A _S formed from the methacrylic acid alkyl ester, and a soft segment A _H formed from the acrylic acid alkyl ester, -A _S -A _H -A _S - tri-block polymers combined with, -A _S -A _H - di-block polymer and the like bound to. A triblock polymer and a diblock polymer may be used in combination.

The block copolymer (A) has a polymer portion (hard segment) of a methacrylic acid alkyl ester having 1 to 3 carbon atoms and a polymer portion (soft segment) of an acrylic acid alkyl ester having 1 to 8 carbon atoms. ), So it is possible to make a hot melt type adhesive by utilizing each polymer part (segment). The hard segment can enhance the cohesive force of the hot-melt adhesive, and the soft segment can be easily wetted with the adherend by using the surfactant (C) or the tackifier (D) described later. Now, adhesive strength can be imparted.

Protective (antifouling) sheets, that is, protective sheets with flame-retardant adhesives are attached to various materials such as glass, metal, and enamel, in addition to cloth and leather products. Since the block copolymer (A) contains an ester bond, it has a higher polarity than a styrene-based elastomer and easily adheres to metal or glass.
Further, in the styrene-based elastomer, the styrene block portion, which is a hard segment of the styrene-based elastomer, is easily plasticized by the phosphorus-based flame retardant (B) which is liquid at 23 ° C., which will be described later. As a result, the cohesive force of the flame-retardant adhesive portion in the protective (antifouling) sheet is reduced, and the sticking position is displaced or peeled off even though the period is expected to be protected. Further, when the protective (antifouling) sheet is attempted to be peeled off from the protected object, the flame-retardant adhesive tends to remain on the protected object side and stains the surface of the protected object.
In the block copolymer (A), the polymer portion of the methacrylic acid alkyl ester having 1 to 3 carbon atoms of the alkyl group, which is a hard segment in the block copolymer (A), is a phosphorus liquid at 23 ° C., which will be described later. Since it is not plasticized by the flame retardant (B), the sticking position does not shift or peel off, and even if the protective (antifouling) sheet is peeled off from the protected object, the surface of the protected object is not soiled.

Examples of the methacrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group for forming the hard segment of the block copolymer (A) include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate and isopropyl methacrylate. Is available, and methyl methacrylate is preferred.

Examples of the acrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group for forming the soft segment of the block copolymer (A) include methyl acrylate, ethyl acrylate, n-propyl acrylate, and isopropyl acrylate. , N-butyl acrylate, isobutyl acrylate, isoamyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate can be used, with n-butyl acrylate and 2-ethylhexyl acrylate being preferred.

The block copolymer (A) used in the present invention has a methacrylic acid alkyl ester having an alkyl group for forming a hard segment having 1 to 3 carbon atoms and an alkyl group for forming a soft segment having 1 to 8 carbon atoms. The mass ratio with the acrylic acid alkyl ester is preferably methacrylic acid alkyl ester for forming a hard segment: acrylic acid alkyl ester for forming a soft segment = 10 to 40: 90 to 60 (mass%), and is preferably 15 to 35. : More preferably, it is 85 to 65 (% by mass). It is most preferable to use the tri-block type of -A _S- A _H- A _{S-, and} it is also possible to use the diblock of _{-A S-} A _{H- in combination.}
When the protective sheet with the flame-retardant adhesive is peeled off from the adherend, the hot-melt type flame-retardant adhesive remains more on the adherend because the methacrylic acid alkyl ester for forming the hard segment is 10% by mass or more. It becomes difficult. On the other hand, when the methacrylic acid alkyl ester is 40% by mass or less, the wettability to the adherend is improved at room temperature, and the sticking stability to the adherend is improved.

Examples of such block copolymers (A) include Clarity LA2140, LA2250, LA2230 (all manufactured by Kuraray Co., Ltd.), and each of them can be used alone or in combination. be.

The melt flow rate (hereinafter referred to as MFR) of the block copolymer (A) of the present invention at 190 ° C. and 2.16 kgf / cm ² is preferably 1 to 320 g / 10 minutes, preferably 1 to 60 g / 10 minutes. Is more preferable, and further preferably 1 to 35 g / 10 minutes. When the MFR is 1 g / 10 minutes or more, thread towing is less likely to occur and the coatability is improved. When the MFR is 320 g / 10 minutes or less, even if the protective (antifouling) sheet is peeled off from the protected object, the adhesive is less likely to remain on the protected object.
When a plurality of types of block copolymers (A) are used, only the block copolymers (A) having an MFR in the above range may be used, or the MFR may be used so that the MFR falls within the above range as a whole. A significantly larger one can be used in combination with a smaller MFR.

<Phosphorus flame retardant (B) liquid at 23 ° C>
In the present invention, by containing the phosphorus-based flame retardant (B) that is liquid at 23 ° C., a barrier layer is formed on the surface to block oxygen when the flame retardant adhesive is brought close to fire, and the flame retardant effect is exhibited. do. Further, by using a liquid at 23 ° C., the soft segment in the block copolymer (A) is plasticized, and the wettability to the adherend and the adhesive strength are imparted. When only a solid flame retardant is used at 23 ° C., the adhesive becomes hard and the adhesive strength is considerably reduced. In the present invention, "liquid at 23 ° C." means that the viscosity at 23 ° C. is 12 Pa · s or less.
Examples of the phosphorus-based flame retardant (B) liquid at 23 ° C. include a halogen-free phosphoric acid ester flame retardant and a condensed phosphoric acid ester flame retardant.
The flame retardants of the phosphate ester include trimethyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyldiphenyl phosphate, 2-ethylhexyldiphenyl phosphate, t-butylphenyldiphenyl phosphate, and bis- (t-butylphenyl) phenyl phosphate. , Tris- (t-butylphenyl) phosphate, isopropylphenyldiphenyl phosphate, bis- (isopropylphenyl) diphenyl phosphate, tris- (isopropylphenyl) phosphate, etc.
Flame retardants of condensed phosphate include resorcinol bis-diphenyl phosphate, resorcinol bis-dixylenyl phosphate, bisphenol A bis-diphenyl phosphate, etc.
More preferred are resorcinol bis-diphenyl phosphate, resorcinol bis-dixylenyl phosphate, and bisphenol A bis-diphenyl phosphate.

<Surfactant (C)>
By containing the surfactant (B), the hot-melt type flame-retardant adhesive of the present invention can adjust the strength of the adhesive force, and at the same time, adheres when the protective film is attached to a wall or the like for a long period of time. The increase in power can be suppressed.
In particular, in the composition using the rosin-based or α-methylstyrene-based tackifier (D) described later, the initial adhesive strength is high, and when the protective film is attached for a long period of time, the adhesive strength becomes too strong. It exerts the effect of suppressing.
Examples of the surfactant include nonionic, cationic, anionic, and amphoteric surfactants, and nonionic surfactants are preferable.

Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyalkylene derivative, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, and polyoxyethylene. Hardened castor oil, polyoxyethylene alkylamine, etc.
Examples of cationic surfactants include alkylamine salts and quaternary ammonium salts.
Examples of the anionic surfactant include an alkyl sulfate ester salt, a polyoxyethylene alkyl ether sulfate ester salt, an alkylbenzene sulfone salt, and a fatty acid salt.
Examples of amphoteric substances include alkyl betaine and alkyl amine oxide.
Among these surfactants, nonionic polyoxyethylene alkyl ethers are particularly preferably used.

<Adhesive imparting agent (D)>
In the present invention, the adhesive strength of the flame-retardant pressure-sensitive adhesive can be maintained even if the pressure-sensitive adhesive (D) is not contained, but the adhesive strength of the flame-retardant pressure-sensitive adhesive can be further improved by including the pressure-sensitive adhesive (D). Examples of the tackifier (D) include phenol resins, modified phenol resins, terpene resins, terpene phenol resins, xylenephenol resins, xylene resins, cyclopentadiene-phenol resins, aliphatic and aromatic petroleum resins, and phenols. Examples thereof include modified petroleum resins, rosin esters, hydrogenated rosin esters, low molecular weight polystyrene resins, and terpene resins. The tackifier may be used alone or in combination of two or more.

The hot-melt flame retardant adhesive of the present invention is a block copolymer (A): a phosphorus-based flame retardant (B): a surfactant that is liquid at 23 ° C. in a total of 100% by mass of the above (A) to (D). Activator (C): The tackifier (D) is 35 to 75:10 to 50: 1 to 15:00 to 30 (mass%), and 35 to 70, 15 to 45: 1 to 15:00. It is preferably 25 (% by mass).
When the block copolymer (A) is 35% by mass or more, the cohesive force is increased, and the flame-retardant adhesive is less likely to cause cohesive failure when the protective film is peeled off. The agent is less likely to remain and the surface to be protected is less likely to be soiled. Further, when the block copolymer (A) is 75% by mass or less, the viscosity at the time of melting can be appropriately lowered, and the surface of the sheet-like substrate can be easily uniformly coated with a thin film.
It is important that the phosphorus-based flame retardant (B) liquid at 23 ° C. is 10% by mass or more from the viewpoint of flame retardancy. On the other hand, if it is 50% by mass or less, the cohesive force becomes large, the flame-retardant adhesive is less likely to cause cohesive failure when the protective film is peeled off, and the flame-retardant adhesive is less likely to remain on the protection target such as a wall, and is protected. It becomes difficult to stain the surface of the target.
It is important that the amount of the surfactant (C) is 15% by mass or less from the viewpoint of suppressing / preventing the decrease in the adhesive strength of the pressure-sensitive adhesive.
The tackifier (D) is not essential, but when used, it is used in the range of 30% by mass or less. By using it in the range of 30% by mass or less, even if the protective film is attached for a long period of time in an environment exposed to high temperature, the adhesive strength does not become too strong, and the flame-retardant adhesive is protected when the protective film is peeled off. It is hard to remain on the surface of.

The hot-melt adhesive of the present invention may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, antibacterial agents, deodorants, and fragrances as long as the object of the invention is not impaired.

Examples of the antioxidants include pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and octadecyl-3- (3,5-di-t-butyl-4-). Hydroxyphenyl) propionate, diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, 4,6-bis (octylthiomethyl) -o-cresol, ethylenebis (oxy) Ethyl) bis [3- (5-t-butyl-4-hydroxy-m-tolyl) propionate, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butyl) Phenyl) Pentaerythritol diphosphite and the like can be mentioned. These may be used alone or in combination of two or more.

The above-mentioned phenolic antioxidants donate hydrogen to ROO (peroxy radicals) generated in the chain growth process of autoxidation to stabilize them, and themselves become stable phenoxy radicals protected by ortho-position substituents. It has a function as a radical trapping agent that stops the chain reaction, thereby effectively suppressing thermal deterioration of the resin composition. In particular, it becomes more excellent by using a phenolic antioxidant in combination with a lactone-based antioxidant or a vitamin E-based antioxidant having a faster radical trap reaction than the phenolic antioxidant. In addition, the above-mentioned phosphorus-based antioxidant has a function of non-radically decomposing peroxides and ROOH to stop the chain reaction of the autoxidation process, which effectively deteriorates the heat of the resin composition. Suppress.

The above-mentioned ultraviolet absorber is not particularly limited, and examples thereof include commonly used ones such as salicylic acid type, benzophenone type, and benzotriazole type. These may be used alone or in combination of two or more.

Examples of the above-mentioned light stabilizer include those usually used in the hindered amine system.

The method for producing the hot-melt type flame-retardant adhesive of the present invention is not particularly limited, and any of a melting pot equipped with a roll, a Banbury mixer, a kneader, and a stirrer is used, such as (A) to (D). It is desirable to heat and mix.

<Protective sheet with flame-retardant adhesive>
The protective sheet with a flame-retardant adhesive of the present invention is a flame-retardant pressure-sensitive adhesive portion formed from the hot-melt type flame-retardant pressure-sensitive adhesive of the present invention on at least a part of one surface of a sheet-like base material. Is carried.
In the protective sheet with a flame-retardant adhesive of the present invention, the hot-melt type flame-retardant adhesive of the present invention described above is melted and applied to at least a part of one surface of a sheet-like substrate to be flame-retardant. It can be obtained by providing a pressure-sensitive adhesive portion. It is preferable that the surface side of the provided flame-retardant adhesive portion is covered with a peelable sheet until it is attached.
Alternatively, the protective sheet with a flame-retardant pressure-sensitive adhesive of the present invention melts the hot-melt type flame-retardant pressure-sensitive adhesive of the present invention, and coats at least a part of the peelable surface of the peelable sheet, promptly. It can also be created by stacking sheet-like substrates and crimping them with a pressure roll.
Alternatively, in the protective sheet with a flame-retardant adhesive of the present invention, the hot-melt type flame-retardant adhesive of the present invention described above is melted and applied to a peelable roll such as a silicon roll, and then a sheet-like base material is used. After transferring to, the surface may be covered with a peelable sheet.

Examples of the sheet-like base material include non-woven fabrics and polyethylene terephthalate films.
Examples of the peelable sheet include a polyethylene terephthalate (hereinafter, also referred to as PET) sheet coated with a release agent such as silicone.
Examples of the device for heating and melting the hot melt type flame-retardant adhesive and applying it include a gravure coater, a roll coater, a die coater, and a slit coater.

The protective sheet with a flame-retardant adhesive may be provided on the entire surface as long as the flame-retardant adhesive portion is provided on at least a part of one surface of the sheet-like base material.
When the flame-retardant pressure-sensitive adhesive portion is provided on the entire surface, the pressure-sensitive adhesive ^{is preferably 30 g / m 2} or less, and more preferably 20 g / m ² or less from the viewpoint of price.

Hereinafter, the present invention will be described in detail with reference to Examples, but these Examples are merely one aspect of the present invention, and the present invention is not limited to these Examples.
In the example, "part" means "part by mass" and "%" means "% by mass".

(Examples 1-42), (Comparative Examples 1-8)
The block copolymer (A) and the like, the flame retardant (B), the surfactant (C), the tackifier (D) and the like were added to the kneader provided with the stirrer in the number of copies shown in Tables 1 to 4. A hot-melt type flame-retardant adhesive was prepared by stirring at 180 ° C. for 3 hours, and the flame retardancy and the like were evaluated according to the method described later.

The abbreviations for the block copolymer (A) and the like shown in Tables 1 to 4 are shown below.
(A1): A triblock copolymer of methyl methacrylate and n-butyl acrylate in which the proportion of methyl methacrylate is 30% by mass (MFR: 25 g / 10 minutes).
(A2): A triblock copolymer of methyl methacrylate and n-butyl acrylate in which the proportion of methyl methacrylate is 20% by mass (MFR: 31 g / 10 minutes).
(A3): A triblock copolymer of methyl methacrylate and 2-ethylhexyl acrylate in which the proportion of methyl methacrylate is 20% by mass (MFR: 1.1 g / 10 minutes).
(A4): A diblock copolymer of methyl methacrylate and n-butyl acrylate in which the proportion of methyl methacrylate is 20% by mass (MFR: 3100 g / 10 minutes).
(A5): Polymethylmethacrylate (A6): Hard segment-soft segment-hard segment triblock copolymer composed of a hard segment of styrene having a ratio of styrene of 19% by mass and a soft segment of isoprene (A2) When (A4) and (A4) were mixed at a ratio of 50:50 (mass ratio), the MFR was 311 g / 10 minutes.

The abbreviations for the flame retardants shown in Tables 1 to 4 are shown below.
(B1): Cresildi 2,6-xylenyl phosphate. Viscosity 1500 mPa · s at 23 ° C
(B2): Bisphenol A bis (diphenyl phosphate). Viscosity at 23 ° C 6000 mPa · s
(B3): 1,3-phenylene bis (dixylenyl) phosphate, solid at 23 ° C., melting point 92 ° C.

The abbreviations for the surfactants listed in Tables 1 to 4 are shown below.
(C1): Polyoxyethylene (number of EO addition moles: 4) Lauryl ether (C2): Polyoxyethylene (number of EO addition moles: 30) Oleyl ether (C3): Polyoxyethylene alkylene alkyl (number of EO addition moles: 2) .5-PO mole number: 1.5-EO mole number: 3) Ether (C4): sorbitan distearate (C5): polyoxyethylene (EO mol number: 20) sorbitan monopalmitate (C6) : Polyoxyethylene tetraoleate (number of moles added with EO: 30) Solbit (C7): Glycol monostearate (C8): Polyoxyethylene (number of moles added with EO: 12) Glycol monolaurate (C9): Polyoxyethylene (Number of moles of EO added: 25) Hardened castor oil (C10): Polyoxyethylene (Number of moles of EO added: 2) Alkylamine (C11): Sodium diallyl sulfosuccinate (C12): Sodium lauryl sulfate (C13): Polyoxyethylene ( Number of moles of EO added: 3) Sodium lauryl ether sulfate (C14): Potash oil Potash soap (C15): Coconatamine acetate (C16): Alkylbenzyl dimethylammonium chloride

The abbreviations for the tackifiers shown in Tables 1 to 4 are shown below.
(D1): Rosin ester softening point 100 ° C.
(D2): Hydrogenated rosin softening point 72 ° C.
(D3): Acid-modified rosin Softening point 128 ° C
(D4): α-methylstyrene resin Softening point 100 ° C.
(D5): Petroleum-based tackifier, aliphatic hydrocarbon resin Softening point 100 ° C.
(D6): Petroleum-based tackifier, aliphatic / aromatic copolymer softening point 115 ° C.
(D7): Terpene phenol resin softening point 112 ° C.

<Flame retardant test>
A glass rod having a diameter of 7 mm and a length of 250 mm is dipped in a hot melt type flame-retardant adhesive melted at 180 ° C. for 30 seconds, coated, pulled up, cooled and solidified at room temperature, and left as it is for 24 hours. It was used as a sample.
At room temperature, turn the coaching part of the sample downward, tilt the tip to a 45 ° angle, bring the gas burner fire close to the tip for 5 seconds, check the ignition of the hot melt adhesive, and then fire the gas burner. We observed how the hot melt adhesive burned and how it was extinguished.
◎: When the fire of the gas burner was kept away, it was digested.
〇: The hot-melt adhesive was still burning even when the gas burner was turned away, but it went out within 1 second.
Δ: The hot melt type adhesive was still burning even when the gas burner was kept away from the fire, but it was extinguished within 1 second and 5 seconds.
X: The hot melt adhesive continues to burn even if the gas burner is kept away from the fire, even if it exceeds 5 seconds.
△ or more can be used

<Coatability test>
A state of application when a hot-melt type flame-retardant adhesive is applied to a peelable PET having a thickness of 25 μm at a coating temperature of 160 ° C. and a speed of 20 m / min using a roll coater.
◎: Uniform application state without thread towing 〇: Slightly towed thread, but uniform application state ×: Many thread towing and uneven application state 〇 More than can be used

<Adhesive strength test-initial>
Using a roll coater, a hot-melt type flame-retardant adhesive was applied to a 25 μm peelable PET at a coating temperature of 160 ° C. and a speed of 20 m / min, and immediately after that, a PET not peeled to a thickness of 25 μm. , And the non-woven fabric, respectively, left for 24 hours under the conditions of 23 ° C. and 65% RH, and then cut into a size of 100 mm × 25 mm to prepare a test sample.
Peel off the peelable PET, attach each test sample to the entire surface of a SUS plate and a glass plate that are one size larger than the test sample, press them back and forth twice with a roll with a load of 2 kg, leave them for 1 hour, and then leave them at 23 ° C. In an environment of 65% RH, 180 ° peeling was performed at a speed of 200 mm / min, and the strength at that time was measured.
⊚: 2N / 25mm or more 〇: 0.5N / 25mm or more and less than 2N / 25mm ×: 0.5N / 25mm or more 〇 or more can be used

<Heat resistance test>
Peel off the peelable PET from the test sample similar to the adhesive strength test, attach each test sample to the entire surface of the SUS plate and glass plate, which are one size larger than the test sample, respectively, and roll with a load of 2 kg. Reciprocating crimping. Then, in an oven at 50 ° C., the surface to which each test sample was attached was turned downward and left for one month, and the state of attachment and dropping was observed.
◎: No dropout, no peeling ×: Dropped or peeled ◎ can be used For those with “×: Dropped or peeled” in the heat resistance test, the adhesive strength after the following heat resistance test Since the adhesive residue after the test and peeling could not be evaluated, it was marked with "-" in Table 4.

<Adhesive strength test after heat resistance test>
The sample after the heat resistance test was allowed to stand in an atmosphere of 23 ° C. and 65% RH for 2 hours, and then a peeling test was conducted under the same conditions as in the initial adhesive strength test, and the peeling force was evaluated according to the following criteria. did.
⊚: 0.5N / 25mm or more or 6N / 25mm or less 〇: 6N / 25mm or more but 9N / 25mm or less ×: 0.5N / 25mm or less or 9N / 25mm or more 〇 or more Available

<Remaining glue after peeling>
When the adhesive strength after the above heat resistance test was measured, the state of transfer of the flame-retardant adhesive to the SUS plate and the glass plate, which were adherends, was visually observed.
⊚: There was no transfer of the hot melt adhesive.
〇: Transferring of 10% or less of the pasted area was observed, but it can be easily removed by hand.
X: Transfer of more than 10% of the pasted area was observed, or transfer was less than 10%, but the adhesive could not be removed by hand.
〇 or more can be used

Claims (8)

In the total of 100% by mass of the following (A) to (D),
Block copolymer (A) of a methacrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms and an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (A) 35 to 75% by mass, phosphorus liquid at 23 ° C. A hot melt type flame retardant pressure-sensitive adhesive containing 10 to 50% by mass of a flame retardant (B), 1 to 15% by mass of a surfactant (C), and 0 to 30% by mass of a tackifier resin (D). The mass ratio of the methacrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group to the acrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group is the methacrylic acid alkyl ester: the acrylic acid alkyl ester = 10 to 40. : 90 to 60, the hot melt type flame-retardant pressure-sensitive adhesive according to claim 1. The hot melt type flame-retardant adhesive according to claim 1 or 2, wherein the block copolymer (A) has a ^{melt flow rate of 1 to 320 g / 10 minutes at 190 ° C. and 2.16 kgf / cm 2.} Any of claims 1 to 3, wherein the block copolymer (A) is a block copolymer of methyl methacrylate and n-butyl acrylate, or a block copolymer of methyl methacrylate and 2-ethylhexyl acrylate. The hot melt type flame-retardant adhesive according to item 1. The hot-melt type flame-retardant pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the surfactant (C) is a cationic, nonionic, anionic, or amphoteric surfactant. .. The hot-melt type flame-retardant adhesive according to claim 5, wherein the surfactant (C) is a nonionic surfactant. A flame-retardant pressure-sensitive adhesive portion formed from the hot-melt type flame-retardant pressure-sensitive adhesive according to any one of claims 1 to 6 is supported on at least a part of one surface of the sheet-like base material. Protective sheet with flame-retardant adhesive. The hot-melt type flame-retardant pressure-sensitive adhesive according to any one of claims 1 to 6 is melted and applied to at least a part of one surface of a sheet-like base material to provide a flame-retardant pressure-sensitive adhesive portion. A method for manufacturing a protective sheet with a flame-retardant adhesive, which comprises.