JPH09286958A - Flame retardant tacky film and tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a flame retardant tacky film, consisting essentially of an alkyl (meth)acrylate capable of providing a high shear strength and bonding strength, having flame retardance without containing any halogen and further a high adhesive strength and useful as automobiles, household appliances, etc. SOLUTION: This flame retardant tacky film is obtained by forming a composition comprising (A) 100 pts.wt. copolymer prepared by copolymerizing a 4-14C alkyl (meth)acrylate with a vinyl monomer copolymerizable with the alkyl (meth)acrylate and (B) 5-70 pts.wt. mixture comprising three components of (i) ammonium polyphosphate, (ii) a nitrogen-containing compound of the formula (R<1> to R<3> are each H, a 1-16C hydroxyalkyl, dihydroxyalkyl or hydroxyaryl, etc.) and (iii) a metallic oxide into a filmy shape. The resultant film has >=50% percentage of stress relaxation after 20min when stretched to 100%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant adhesive film and tape.

[0002]

2. Description of the Related Art Conventionally, an adhesive tape having a polyethylene foam, a chloroprene foam, a urethane foam, an acrylic foam as a base material and an acrylic or rubber adhesive layer provided on both sides of the base material is used for automobiles. It is used in the fields of home appliances, office automation equipment, and home building materials. The double-sided pressure-sensitive adhesive tape using this foam as a base material can be easily bonded to two surfaces without solvent, and since the stress relaxation rate of this base material is large, the adherend surface has relatively fine irregularities. Also, since the base material is deformed and adheres closely to this uneven surface, it is used in various fields. However, the cohesive failure strength of the foam base material is low, and therefore, there is a problem that it is difficult to obtain sufficient adhesive strength such as shear strength and peel strength, which is usually determined by the cohesive failure strength. Therefore, the Applicant has found that an adhesive tape containing alkyl (meth) acrylate as a main component has high breaking strength,
Moreover, the invention was filed as Japanese Patent Application Laid-Open No. 7-90028, inventing that high adhesive strength can be obtained.

[0003]

In the field of using this adhesive tape, that is, in the fields of automobiles, home appliances, office automation equipment, housing construction materials, etc., the adhesive tape is often required to have flame retardancy. However, double-sided adhesive tape based on foam,
The pressure-sensitive adhesive tape containing the alkyl (meth) acrylate as a main component has a problem of poor flame retardancy. In addition, as a method of making a resin flame-retardant, a method of adding a halogen-containing compound is generally used, but a large amount of harmful smoke is generated during combustion, which is corrosive to equipment and harmful to humans. Etc. has become a problem, and flame retardancy free of halogen is required.

Therefore, an object of the present invention is to provide a flame-retardant pressure-sensitive adhesive film and tape in which a pressure-sensitive adhesive tape containing an alkyl (meth) acrylate as a main component, which provides high shear strength and adhesive strength, is made flame-retardant without containing halogen. Is to provide.

[0005]

The present invention achieves the above object, and the invention according to claim 1 provides an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms and the alkyl (meth) acrylate. Mixture 5 consisting of 100 parts by weight of a copolymer obtained by copolymerizing a vinyl monomer copolymerizable with (meth) acrylate, ammonium polyphosphate, a nitrogen-containing compound represented by the following structural formula and a metal oxide 5
To 70 parts by weight is a flame-retardant adhesive film formed into a film, and the stress relaxation rate after 20 minutes when the flame-retardant adhesive film is stretched by 100% is 5
The present invention relates to a flame-retardant adhesive film having a content of 0% or more.

[0006]

Embedded image

The invention according to claim 2 is an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms,
100 parts by weight of a copolymer obtained by copolymerizing the vinyl monomer copolymerizable with the alkyl (meth) acrylate,
A flame-retardant pressure-sensitive adhesive film, comprising a composition comprising 5 to 50 parts by weight of a phosphorus compound and 2 to 15 parts by weight of heat-expandable graphite, which is formed into a film.
The present invention relates to a flame-retardant pressure-sensitive adhesive film having a stress relaxation rate of 50% or more after 20 minutes when stretched by%.

The invention according to claim 3 is an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms,
100 parts by weight of a copolymer obtained by copolymerizing the vinyl monomer copolymerizable with the alkyl (meth) acrylate,
A flame-retardant pressure-sensitive adhesive film obtained by molding a composition comprising 5 to 70 parts by weight of ammonium polyphosphate and / or 2 to 30 parts by weight of red phosphorus into a film, wherein the flame-retardant pressure-sensitive adhesive film is stretched by 100%. The present invention relates to a flame-retardant pressure-sensitive adhesive film having a stress relaxation rate of 50% or more after 20 minutes.

Further, the invention according to claim 4 is based on claims 1 to 3.
In any of the inventions described above, the alkyl group has 4 carbon atoms.
To 14 parts by weight of an alkyl (meth) acrylate of 100 to 100 parts by weight of a copolymer obtained by copolymerizing a vinyl monomer copolymerizable with the alkyl (meth) acrylate.
The present invention relates to a flame-retardant pressure-sensitive adhesive film containing 0.5 to 175 parts by weight of fine particles or hollow fine particles having an average particle diameter of 1 to 150 μm or a volume fraction of 10 to 50% by volume.

Further, the invention of claim 5 is the invention of claims 1 to 4.
It relates to a flame-retardant pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer provided on at least one surface of any one of the flame-retardant pressure-sensitive adhesive films.

The alkyl (meth) acrylate having 4 to 14 carbon atoms used in the present invention is an ester obtained from a monohydric alcohol having an alkyl group having 4 to 14 carbon atoms and acrylic acid or methacrylic acid. Say. The reason for using the alkyl (meth) acrylate having 4 to 14 carbon atoms is that when the carbon number is 3 or less, the glass transition point of the alkyl (meth) acrylate is high, and therefore, there is no tackiness at room temperature. In addition, an alkyl (meth) acrylate having 15 or more carbon atoms has a high glass transition point, and sufficient tackiness cannot be obtained at room temperature. Among these alkyl (meth) acrylates, alkyl (meth) acrylates having 4 to 12 carbon atoms are particularly preferable. Examples of such compounds include n-butyl (meth) acrylate, hexyl (meth) acrylate, and 2-ethylhexyl (meth).
Acrylate, isooctyl (meth) acrylate, n
-Octyl (meth) acrylate, isononyl (meth)
There are alkyl (meth) acrylates such as acrylate, decyl (meth) acrylate, and dodecyl (meth) acrylate.

These alkyl (meth) acrylates may be used alone or in combination of two or more. In particular, in view of the balance between tackiness and cohesiveness, etc., an alkyl (meth) acrylate having a glass transition temperature (Tg) of -50 ° C or lower is usually used, or an alkyl (meth) acrylate having a glass transition temperature (Tg) of -50 ° C or lower is used. It is preferable to use (meth) acrylate as a main component and to use other alkyl (meth) acrylate in combination. When used in combination as described above, an alkyl (meth) acrylate having 1 to 3 carbon atoms can also be used.

The content of the alkyl (meth) acrylate having 4 to 14 carbon atoms may be appropriately selected, but if it is less than 50% by weight based on 100 parts by weight of the monomer in the copolymer,
The cohesive force becomes too strong, and the pressure-sensitive adhesiveness decreases, and 98
When the content exceeds 50% by weight, the cohesive force becomes too low and a high shear strength cannot be obtained, so 50 to 98% by weight is preferable. Further, it is preferably 70 to 95% by weight.

There are various vinyl monomers copolymerizable with the alkyl (meth) acrylate used in the present invention.
Vinyl monomers containing polar groups are preferred. Examples of the polar group-containing vinyl monomer include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, anhydrides thereof, and the like, a carboxyl group-containing vinyl monomer having a double bond in the molecule, and (meth) acrylonitrile. Nitrogen-containing vinyl monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and 2- Hydroxy acids such as hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, caprolactone-modified (meth) acrylate Inclusion vinyl monomers.

As other vinyl monomers copolymerizable with alkyl (meth) acrylate, vinyl acetate, vinyl propionate, styrene, isobornyl (meth) acrylate and the like can be used. The above alkyl (meth)
The content of the vinyl monomer copolymerizable with the acrylate may be appropriate, but if it is less than 2.0% by weight, the cohesive force becomes too low and a high shear force cannot be obtained. Too high pressure-sensitive adhesiveness is impaired, so 2
-50% by weight is preferred.

In addition to the above components, a polyfunctional vinyl monomer can be added for the purpose of obtaining excellent cohesive strength. Examples of such polyfunctional vinyl monomers include hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth)
Acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) Acrylate, allyl (meth) acrylate, vinyl (meth) acrylate,
Divinylbenzene, epoxy (meth) acrylate and the like are preferable.

The amount of the polyfunctional vinyl monomer used varies depending on the type and may be appropriate, but generally, if it is less than 0.01 parts by weight, the crosslinking density is low and the necessary cohesive force cannot be obtained.
If it exceeds 1 part by weight, the crosslink density becomes high, and the cohesive force is too high and the pressure-sensitive adhesiveness is impaired. Therefore, 0.01 to 1 part by weight is preferable, and 0.02 to 0.8 part by weight is more preferable. . As a method for obtaining a copolymer by copolymerizing this alkyl (meth) acrylate, a monomer copolymerizable with this alkyl (meth) acrylate, and if necessary, a mixed monomer in which a polyfunctional vinyl monomer or the like is mixed , For example, a method of copolymerizing with a thermal polymerization initiator, a method of adding a photopolymerization initiator and copolymerizing by irradiating with radiation, and the like, a mixed monomer containing the above photopolymerization initiator added to the substrate. The photopolymerization method is most preferable in that a relatively thick film can be collectively obtained by applying and photopolymerizing.

In order to carry out photopolymerization, a photopolymerization initiator may be added to the mixture and irradiated with light such as ultraviolet rays or visible light.
Examples of the photopolymerization initiator used here include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone "Darocur 2959: manufactured by Ciba Geigy"; α-hydroxy-α, α'-dimethyl. -Acetophenone "Darocur 1173: Ciba Geigy";
Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone "Irgacure 651: manufactured by Ciba-Geigy"; 2-hydroxy-2-cyclohexylacetophenone "Irgacure 184: manufactured by Ciba-Geigy" and the like acetophenones; benzyldimethyl ketal, etc. Ketal-based; other examples include halogenated ketones, acylphosphine oxides, acylphosphonates, and the like. If the amount of this photopolymerization initiator is less than 0.01 parts by weight, the polymerization conversion rate will be lowered, and only a copolymer having a strong monomer odor will be obtained, and if it exceeds 5 parts by weight, the amount of radicals generated will increase and the molecular weight will increase. 0.01 to 5 parts by weight is preferable, since the amount will be reduced and the necessary cohesive force cannot be obtained.
More preferably, it is 0.05 to 3 parts by weight.

As the ammonium polyphosphate used in the invention of claim 1, various ones can be used, but those having a degree of polymerization of 200 to 1000 are preferable, and the surface is coated with a melamine / formaldehyde resin. It is preferable that the powder has good properties and is hardly soluble in water. Claim 1
As the nitrogen-containing compound used in the described invention, isocyanuric acid, mono (hydroxymethyl) isocyanurate, tris (hydroxymethyl) isocyanurate, mono (dihydroxymethyl) isocyanurate, bis (hydroxymethyl) isocyanurate, bis (dihydroxy) Methyl) isocyanurate, tris (dihydroxymethyl) isocyanurate, mono (2-hydroxyethyl) isocyanurate, bis (2-hydroxyethyl)
Isocyanurate, tris (2-hydroxyethyl) isocyanurate, tris (1,2-dihydroxyethyl) isocyanurate, tris (3-hydroxypropyl) isocyanurate, tris (2,3-dihydroxypropyl) isocyanurate, tris (4 -Hydroxybutyl) isocyanurate, Tris (3,4-dihydroxybutyl) isocyanurate, Tris (8-hydroxyoctyl) isocyanurate, Tris (4-hydroxyphenyl) isocyanurate, Tris (2,4-dihydroxyphenyl) isocyanurate , Tris (2,3
-Dihydroxyphenyl) isocyanurate, etc.,
They may be used alone or in combination of two or more. Among them, tris (2-hydroxyethyl) isocyanurate is preferable from the viewpoint of flame retardancy.

There are various metal oxides used in the invention of claim 1, and particularly preferable ones are magnesium oxide, aluminum oxide, titanium oxide, nickel oxide, zinc oxide and the like. Among them, titanium dioxide is particularly preferable. In the invention according to claim 1, good flame retardancy can be obtained only when the ammonium polyphosphate, the nitrogen-containing compound and the metal oxide are used in combination. The mixing ratio at this time may be arbitrary, but ammonium polyphosphate: nitrogen-containing compound: metal oxide = 40 to 94.
The range of 9% by weight: 5 to 40% by weight: 0.1 to 20% by weight is preferable. This three-component system expands the carbonized layer that is burned and carbonized, and exhibits flame retardancy. When the composition ratio of these is within this range, the volume expansion of the residue after heating is large and the flame retardance is sufficient. Is obtained, which is preferable.

The ratio of these three components to the copolymer containing alkyl (meth) acrylate as the main component is 5 to 70 parts by weight based on 100 parts by weight of the copolymer containing alkyl (meth) acrylate as the main component. Part used. The reason for this is 5
This is because if the amount is less than parts by weight, sufficient flame retardancy cannot be obtained, and if the amount exceeds 70 parts by weight, the adhesive strength decreases. It is preferably 10 to 50 parts by weight, more preferably 20 to 40 parts by weight.

Examples of the phosphorus compound used in the present invention include phosphoric acid esters such as triphenyl phosphate, octyldiphenyl phosphate, trioctyl phosphate, tricresyl phosphate; sodium phosphate, potassium phosphate, magnesium phosphate, zinc phosphate, phosphoric acid. Metal salts of phosphoric acid such as aluminum or hydrates of these metal salts; salts of phosphoric acid with ammonia or amines such as ammonium phosphate, ammonium polyphosphate, phosphate of ethylenediamine, phosphate of diethylenetriamine and phosphate of guanidine; , Phosphines,
Examples include phosphine oxides, phosphonic acids such as t-butylphosphonic acid and phenylphosphonic acid, melamine-modified ammonium polyphosphate, and red phosphorus. These may be used alone or in combination of two or more.

Among the above phosphorus compounds, ammonium polyphosphate is particularly preferable because it is easy to handle and excellent flame retardancy can be obtained. Although various types of ammonium polyphosphates can be used, those having a degree of polymerization of 200 to 1000 are preferable, and the surface thereof is coated with a melamine / formaldehyde resin and is in the form of a powder having good fluidity and hardly soluble in water. Those are preferable. The amount of the phosphorus compound used is the copolymer 10
5 to 50 parts by weight is used with respect to 0 parts by weight. This is 5
If it is less than 50 parts by weight, sufficient flame retardancy cannot be obtained, and if it exceeds 50 parts by weight, the adhesive strength is lowered. It is preferably 10 to 40 parts by weight, more preferably 15 to 30 parts by weight.

As the heat-expandable graphite used in the invention of claim 2, graphite which expands when heated can be used.
For example, powders of natural scaly graphite, pyrolytic graphite, quiche graphite and the like are mixed with inorganic acids such as concentrated sulfuric acid, nitric acid, selenate and concentrated nitric acid, perchloric acid, perchlorate, permanganate, dichromic acid. A graphite intercalation compound is produced by treatment with a strong oxidant such as salt or hydrogen peroxide, and a crystalline compound that maintains the layered structure of carbon is preferable.

In the present invention, the thermally expandable graphite obtained by the above acid treatment is further neutralized with ammonia, an aliphatic lower amine, an alkali metal compound, an alkaline earth metal compound or the like before use. preferable. Examples of the aliphatic lower amine include monomethylamine, dimethylamine, trimethylamine, ethylamine, propylamine and butylamine. Examples of the alkali metal compounds and alkaline earth metal compounds include hydroxides, oxides, carbonates, sulfates, organic acid salts and the like of calcium, sodium, calcium, barium, magnesium and the like.

If the volume expansion coefficient of the heat-expandable graphite when expanded is small, sufficient flame retardancy cannot be obtained. Therefore, the volume expansion coefficient when the heat-expandable graphite is rapidly heated to 800 ° C. or higher. 100 times or more heat-expandable graphite is preferable. This volume expansion coefficient is measured by adding 1 ml of thermally expansive graphite to a platinum crucible having an internal volume of 100 ml,
It is put in an electric furnace heated to 00 ° C or higher. 30 after input
After a lapse of seconds, the platinum crucible is taken out and allowed to cool to room temperature, and the expansion coefficient of volume is measured. When the amount of the heat-expandable graphite expanded by heating completely fills the inner volume of the crucible, the volume expansion coefficient is 100 times or more.

If the particle size of the above-mentioned thermally expandable graphite is small, the coefficient of thermal expansion becomes small and sufficient flame retardancy cannot be obtained, while if it is large, the dispersibility becomes poor and the physical properties of the resulting composition deteriorate. 50-200 mesh is preferred. The amount of the thermally expandable graphite used is 2 to 15 with respect to 100 parts by weight of the copolymer.
Parts by weight. This is because if it is less than 2 parts by weight, sufficient flame retardancy cannot be obtained, and if it exceeds 15 parts by weight, the adhesive strength is lowered. It is preferably 3 to 12 parts by weight, more preferably 5 to 10 parts by weight.

The ammonium polyphosphate used in the invention of claim 3 is the same as the ammonium polyphosphate used in the invention of claim 1. The amount of ammonium polyphosphate used is 5 per 100 parts by weight of the copolymer.
７０70 parts by weight. This is because if it is less than 5 parts by weight, sufficient flame retardancy cannot be obtained, and if it exceeds 70 parts by weight, the adhesive strength is reduced. It is preferably 5 to 50 parts by weight, more preferably 10 to 40 parts by weight. The red phosphorus used in the invention of claim 3 may be a commercially available one, but from the viewpoint of moisture resistance and handling safety (spontaneous ignition), the surface of red phosphorus particles is coated with a resin. Is preferred. The red phosphorus is used in an amount of 2 to 30 parts by weight based on 100 parts by weight of the copolymer. This is because if it is less than 2 parts by weight, sufficient flame retardancy cannot be obtained, and if it exceeds 30 parts by weight, the adhesive strength is lowered.

Further, in the present invention, various substances can be added to the composition in addition to the above compounds. For example, a tackifying resin may be added to increase the tackiness of the composition. Suitable tackifying resins include rosin-based resins, modified rosin-based resins, terpene-based resins, terpene-phenolic resins, C5 and C9-based petroleum resins, coumarone resins, and hydrogenated products thereof, alone or in combination. Can be used. However, by blending these with the photopolymerizable composition,
During the photopolymerization reaction, the polymerization rate may decrease or the molecular weight may decrease. Therefore, it is necessary to appropriately adjust the amounts of the chain transfer agent, the polyfunctional vinyl monomer and the like at this time.

The flame-retardant pressure-sensitive adhesive film of the present invention is obtained by molding the above composition into a film and has a stress relaxation rate of 50% after 20 minutes when the flame-retardant pressure-sensitive adhesive film is stretched by 100%. The above is characterized, but the stress relaxation rate is measured by the following method. That is, using a tensile tester, the distance between the upper and lower chucks is set to 40 mm, the film width is 20 mm, 100% extension is performed, and the residual stress after 20 minutes is measured. The stress relaxation rate is a percentage of the value obtained by dividing the value obtained by subtracting the residual stress after 20 minutes from the initial maximum stress at that time by the initial maximum stress "(initial maximum stress-2
The residual stress after 0 minutes) × 100 / initial maximum stress ”.

The stress relaxation rate of the flame-retardant adhesive film of the present invention is 50% or more, preferably 60% or more. This stress relaxation property plays an important role of the adhesive tape. In other words, when bonding the bonded body with an adhesive film or tape,
If the stress relaxation rate is large, even if there is relatively fine unevenness on the adherend surface, it deforms and adheres according to this uneven surface, and the stress is relieved when peeling the joined body, so the entire joined body is joined. Increases strength. If the stress relaxation rate of the pressure-sensitive adhesive film or tape is small, the pressure-sensitive adhesive film or tape will not be deformed depending on the surface to be bonded, and the stress at the time of peeling between the bonded body and the pressure-sensitive adhesive tape will be concentrated on a part, resulting in low bonding strength.

When the stress relaxation rate of the flame-retardant pressure-sensitive adhesive film according to any one of claims 1 to 3 is 50% or more, the film can be used as it is, but when the stress relaxation rate is less than 50%, the stress relaxation can be performed by an appropriate method. It is necessary to increase the rate.

A preferred method of increasing the stress relaxation rate is to add fine particles or hollow fine particles to the composition. The most preferred method is to add 0.5 to 175 parts by weight of fine particles or hollow fine particles having an average particle size of 1 to 150 μm to 100 parts by weight of the copolymer as described in claim 4, or a volume fraction of 10 to 10. This is a method of containing 50% by volume. Examples of the fine particles or hollow fine particles having an average particle diameter of 1 to 150 μm used here include inorganic hollow particles such as glass balloons, shirasu balloons and fly ash balloons, polymethylmethacrylate, acrylonitrile-vinylidene chloride copolymer, polystyrene, and phenol. Examples thereof include hollow particles of synthetic resin such as resin; inorganic particles such as glass beads, silica beads and synthetic mica; and organic particles such as polyethyl acrylate, polyurethane, polystyrene, polyethylene and polypropylene. Average particle size 1
If it is less than μm or exceeds 150 μm, high stress relaxation characteristics cannot be obtained, so that an average particle size of 1 to 150 μm is used.

The fine particles or hollow fine particles having an average particle diameter of 1 to 150 μm are 0.1% to 100 parts by weight of the copolymer.
Use 5 to 175 parts by weight. The hollow fine particles having a small specific gravity are preferably 0.7 to 10 parts by weight, and the inorganic hollow fine particles and the synthetic resin fine particles having a specific gravity of about 1 are preferably 10 to 60 parts by weight. Also, for heavy inorganic fine particles having a specific gravity of 2 or more, 70
~ 150 parts by weight are preferred. The volume fraction is 10-5
0% by volume is contained. If this volume fraction is less than 10% by volume or exceeds 50% by volume, high stress relaxation characteristics cannot be obtained.

The composition of the invention described in any one of claims 1 to 4 formed into a film has tackiness by itself, but depending on the application, a stronger adhesive force may be required. There may be a shortage, but in such a case,
As described in claim 5, an adhesive layer may be provided on one surface or both surfaces. As the pressure-sensitive adhesive used in this pressure-sensitive adhesive layer, a conventionally known pressure-sensitive adhesive such as an acrylic type, a rubber type, or a silicone type can be used. Also, this adhesive is a solvent type,
Any of a water dispersion type, a hot melt type, and a radiation curing type that is cured by radiation such as ultraviolet rays and electron beams may be used. When the pressure-sensitive adhesive is a hot-melt type or an ultraviolet ray-curable type, it can be directly applied onto a film-shaped product of the composition of the present invention. When the pressure-sensitive adhesive is a solvent type or a water-dispersed type, the pressure-sensitive adhesive is applied onto a release-treated film and dried to form a pressure-sensitive adhesive layer. It may be transferred and laminated on the adhesive film described in 4.

In order to enhance the adhesive force between the adhesive layer and the adhesive film according to any one of claims 1 to 4, an adhesive force enhancing layer may be provided between the adhesive tape and the adhesive layer. The compound used in the adhesion enhancing layer, polyamine compounds, polyfunctional isocyanate compounds, polyfunctional epoxy compounds, polyfunctional carbodiimide compounds, polyfunctional oxazoline compounds, chloroprene, chlorinated natural rubber, compounds containing a methylol group, There are methoxymethyl compounds and the like. In the present invention, an alkyl (meth) acrylate and a copolymer obtained by copolymerizing a vinyl monomer copolymerizable with the alkyl (meth) acrylate, and in the invention according to claim 1, ammonium polyphosphate, a nitrogen-containing compound and A composition comprising a metal oxide, in the invention according to claim 2, a composition comprising a phosphorus compound and thermally expandable graphite, in the invention according to claim 3, comprising a composition comprising ammonium polyphosphate and / or red phosphorus. In the invention according to claim 4,
Compositions containing fine particles or hollow fine particles in addition to the compositions according to claims 1 to 3 are formed into films.

The composition may be formed into a film by melting the copolymer, adding each flame retardant and other necessary substances therein, and uniformly mixing them to form a film. However, after adding each flame retardant and other necessary substances to vinyl monomers such as alkyl (meth) acrylate and mixing them uniformly, they are molded into a sheet and co-polymerized with vinyl monomers such as acrylic (meth) acrylate. It may be polymerized to obtain a flame-retardant adhesive film. Further, a photopolymerization method is preferable as this polymerization method.

The best method for producing the flame-retardant adhesive film or tape of the present invention by the photopolymerization method will be described in more detail. An alkyl (meth) acrylate and a vinyl monomer copolymerizable with the alkyl (meth) acrylate are described. And a photopolymerization initiator, if necessary, a polyfunctional vinyl monomer, a tackifying resin and the like, and in the invention according to claim 1, ammonium polyphosphate, a nitrogen-containing compound and a metal oxide are added, In the invention of claim 2, a phosphorus compound and thermally expandable graphite are added, in the invention of claim 3, ammonium polyphosphate and / or red phosphorus is added, and in the invention of claim 4, the above-mentioned difficult Fine particles or hollow fine particles are further added on top of the addition of the flame retardant, and the fine particles or hollow fine particles are placed on the release treated film to have a desired thickness, for example, 50 μm to 5 mm
When the coating is applied to a sheet having a thickness of, and if necessary, a release film for a cover is adhered on this, and light is radiated from above to polymerize the vinyl monomer such as the alkyl (meth) acrylate. A flame-retardant adhesive film can be manufactured.
Further, in the case of the invention described in claim 5, an adhesive layer is provided on this one surface or both surfaces. When the film-like composition is in the form of a tape, the film-like composition becomes a flame-retardant adhesive tape as it is, and when it is not in the form of a tape,
A flame-retardant pressure-sensitive adhesive tape can be manufactured by molding it into a tape shape.

This desired thickness, for example, 50 μm to 5 m
When a sheet having a thickness of m is applied and the viscosity is too low to form a sheet having a desired thickness, it is necessary to increase the viscosity. For example, when the thickness of the sheet is 100 μm or less, the coating can be performed at 1000 cps and the TI value is about 1.5, but when the thickness of the sheet is more than that, it is necessary to make the viscosity high. As means for thickening, acrylic rubber, nitrile rubber, elastomer such as styrene-isoprene-styrene (SIS), thermoplastic resin such as polymethylmethacrylate (PMMA), polystyrene (PSt), etc. are dissolved in the mixed vinyl monomer. Good to do.
Also, the viscosity can be increased by mixing silica or alumina having an average diameter of 5 μm or less. Further, the viscosity can be increased by polymerizing a part of the vinyl monomer without adding the thermoplastic resin or silica as described above. In this case, it is preferable to copolymerize with a catalyst or the like before adding the polyfunctional vinyl monomer, because formation of microgel can be prevented. The formation of this microgel causes defects such as streaks during coating. The mixed vinyl monomer that is partially polymerized should be 1.5% to 60% of the total monomers. If it is 1.5% or less, the required viscosity cannot be obtained, and if it is 60% or more, the viscosity becomes too high to be applied in a film form.

The lamps used for photopolymerization vary depending on the kind of the photopolymerization initiator, but usually a light wavelength of 40
A material having an emission distribution of 0 nm or less is used. Examples of the light source that emits a light emission distribution having a light wavelength of 400 nm or less include a low pressure mercury lamp, a medium pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excited mercury lamp, and a metal halide lamp. Among them, the chemical lamp efficiently emits light in the active wavelength region of the photopolymerization initiator, and since light absorption by the composition other than the photopolymerization initiator is small, light is transmitted to the inside and a high-thickness film is formed. It is preferable because the film-shaped composition can be produced. The light irradiation intensity of the film-shaped composition by the lamp is a factor that influences the degree of polymerization of the polymer to be obtained, and is appropriately controlled for each performance of the target film-shaped composition. When a cleavage type photopolymerization initiator having a group is blended, the range is a wavelength region effective for photodecomposition of the photopolymerization initiator (though it varies depending on the photopolymerization initiator, light of 365 nm to 420 nm is usually used). The light intensity is preferably 0.1 to 100 mW / cm ² .

The above photopolymerization is inhibited by oxygen in the air and oxygen dissolved in the film-shaped composition. Therefore, the light irradiation needs a method of removing oxygen. As a method thereof, there is a method in which a film-shaped composition is sandwiched from both sides by a release-treated film such as polyethylene terephthalate (PET) which is release-treated and a release film for a cover, and light is irradiated through this film. Further, the reaction may be carried out in an inert zone having a light transmissive window in which oxygen is replaced by an inert gas such as nitrogen gas or carbon dioxide gas. In the latter method, the oxygen concentration in this irradiation atmosphere is 5000 pp in order to sufficiently polymerize the monomer until the polymerization conversion rate becomes 99.7 or more.
m or less. It is preferably 300 ppm or less.

In the case of rapid reaction, the release treatment film sandwiching the film-like composition or the release treatment film for the cover is heated and contracted by the heat of polymerization to cause defects such as vertical stripes in the resulting adhesive tape. There are cases. In this case, the problem can be solved by controlling the radiant heat from the lamp with the light cut filter, or by allowing the cooling plate to come into contact with the back surface of the sheet opposite to the irradiation surface to cool the sheet.

(Function) In the present invention, when the flame-retardant adhesive film is stretched by 100%, the stress relaxation rate after 20 minutes is 5%.
Since it is 0% or more, even if the surface to be adhered has relatively fine irregularities, the flame-retardant adhesive film deforms and adheres closely according to the surface to be adhered, and when peeled off. The stress of spreads to the whole and is relaxed, so it is difficult to peel off,
It is an adhesive film with high adhesive strength.

According to the invention of claim 1, as the flame retardant,
Since it contains ammonium polyphosphate, a special nitrogen-containing compound, and a metal oxide, it becomes a flame-retardant adhesive film which is not easily burned and is good. Further, in the invention of the second aspect, since the phosphorus compound and the heat-expandable graphite are contained as the flame retardant, it becomes a flame-retardant adhesive film which is hard to burn and is good. or,
According to the invention of claim 3, since ammonium polyphosphate and / or red phosphorus is contained as the flame retardant, a good flame-retardant adhesive film is obtained which is difficult to burn.

Further, in the invention according to claim 4, since the flame-retardant pressure-sensitive adhesive film contains fine particles or hollow fine particles of a special size, the stress relaxation rate becomes large and relatively fine irregularities are formed. It adheres strongly to a certain surface to be adhered and is hard to peel off, resulting in a good adhesive film. Further, in the invention according to claim 5, since the adhesive layer is provided on at least one surface, the adhesive tape has further improved adhesive force.

[0046]

Next, an embodiment of the present invention will be described. (Example 1) 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.01 parts by weight of n-dodecanethiol, 2,2-dimethoxy-2-phenylacetophenone (manufactured by Ciba Geigy, trade name " Irgacure 651 "), 0.1 part by weight, average particle size 20 μm
20 parts by weight of high-density polyethylene fine particles (manufactured by Mitsui Petrochemical Co., Ltd., trade name "Miperon XM-220", specific gravity 0.95), ammonium polyphosphate (Hoechst, hereinafter "A").
PP "), 10 parts by weight, tris (2-hydroxyethyl) isocyanurate (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as" THEIC ") 5 parts by weight, titanium oxide (rutile type) (manufactured by Ishihara Sangyo). After stirring and mixing in a separable flask until 2 parts by weight were uniformly dispersed to produce a composition, nitrogen gas was purged to remove dissolved oxygen.

When the composition was irradiated with ultraviolet rays using a black light lamp, the monomers in the composition were polymerized to raise the temperature and simultaneously increase the viscosity. When the temperature of the composition increased by 5 ° C, the light irradiation was stopped.
The conversion rate of the partially polymerized thickened composition obtained as a result was 3.7.
%, The viscosity was 2200 cps. Further, 0.1 part by weight of hexanediol diacrylate was added, and then the release-treated 38 μm-thick PET film was coated on the release-treated surface so as to have a film thickness of 1.0 mm at the end of the polymerization. Further, this coated surface was covered with the same PET film so that the release-treated surface was in contact with this coated surface.

This covered P using a chemical lamp
From the top of the ET film, the lamp height was adjusted so that the irradiation intensity was ² mW / cm ^2, and irradiation was carried out for 8 minutes to obtain an adhesive film. The residual monomer content at this time was 0.1% or less, and the gel fraction was 96%. After this adhesive film was cut into a strip having a width of 20 mm, the length of the strip-shaped adhesive film after extending for 100 minutes and measuring 20% according to the above-described stress relaxation rate measuring method was 68%. . Hereinafter, it will be simply referred to as a stress relaxation rate (after 20 minutes).

(Example 2) n-butyl acrylate 85
Parts by weight, acrylic acid 15 parts by weight, hydrophilic silica (manufactured by Nippon Aerosil Co., Ltd., trade name "Aerosil 200") 3 parts by weight, APP 5 parts by weight, THE1C 3 parts by weight, titanium oxide 1 part by weight with a dissolver type stirrer for 4 hours 1000 rp
The mixture was stirred and mixed at m to obtain a viscous liquid. 50 parts by weight of a glass balloon having an average particle diameter of 45 μm (manufactured by Asahi Glass Co., Ltd.,
Product name "CEL-STAR-27", specific gravity 0.2
7) 0.1 parts by weight of 2.2-dimethoxy-2-phenylacetophenone and 0.1 parts by weight of hexanediol diacrylate were stirred and mixed until uniform, and then nitrogen gas was purged to remove dissolved oxygen. did. Hereinafter, Example 1
A pressure-sensitive adhesive film having a thickness of 1.0 mm was manufactured in the same manner as in 1. The stress relaxation rate (after 20 minutes) of this pressure-sensitive adhesive film was 70.
%Met.

(Example 3) 70 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of isooctyl acrylate, 10 parts by weight of acrylic acid, 3 parts by weight of hydrophilic silica (manufactured by Nippon Aerosil Co., Ltd., trade name "Aerosil 200"), A
PP 5 parts by weight, THE1C 40 parts by weight, titanium dioxide 5
1000 parts by weight with a dissolver-type stirrer for 4 hours
The mixture was stirred and mixed with to obtain a viscous liquid. 50 parts by weight of a glass balloon having an average particle diameter of 45 μm (made by Asahi Glass Co., Ltd.,
Product name "CEL-STAR-27", specific gravity 0.2
7) 0.1 parts by weight of 2.2-dimethoxy-2-phenylacetophenone and 0.1 parts by weight of hexanediol diacrylate were stirred and mixed until uniform, and then nitrogen gas was purged to remove dissolved oxygen. did. Hereinafter, Example 1
An adhesive film having a thickness of 1.0 mm was manufactured in the same manner as in. The stress relaxation rate (after 20 minutes) of this adhesive tape substrate is 6
It was 0%.

Separately, 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.05 parts by weight of n-dodecanethiol, and 80 parts by weight of ethyl acetate together with a stirrer, a reflux condenser, a thermometer and a dropping funnel. Then, the mixture was charged into a five-necked flask equipped with a nitrogen gas inlet, and dissolved by stirring to form a uniform mixture, and then nitrogen gas was purged for about 30 minutes to remove oxygen existing in the monomer solution. Then, the air in the flask was replaced with nitrogen gas, the temperature was raised with stirring, and this was kept at 70 ° C. to prepare a solution of 0.03 parts by weight of benzoyl peroxide dissolved in 1 part by weight of ethyl acetate. After dropping with a dropping funnel, a polymerization reaction was performed at the same temperature for 10 hours to obtain a copolymer solution.

A solution of the above copolymer in an ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane (trade name "Coronate L55, manufactured by Nippon Polyurethane Industry Co., Ltd.)
E ") was added 2.4 parts by weight (based on 100 parts by weight of the solid content of the copolymer) and uniformly mixed to prepare an adhesive solution. This pressure-sensitive adhesive solution is applied onto a separator so that the thickness when dried is 50 μm, and dried to produce a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is laminated on both sides of each of the above-mentioned pressure-sensitive adhesive films to give a pressure-sensitive adhesive. A tape was manufactured.

(Comparative Example 1) An adhesive film was obtained in the same manner as in Example 1 except that the three-component flame retardant was not added. Stress relaxation rate of the obtained adhesive film (after 20 minutes)
Was 77%.

(Comparative Example 2) 1 part by weight of APP, THEI
An adhesive film was obtained in the same manner as in Example 3 except that C was 2 parts by weight and titanium oxide was 1 part by weight. The stress relaxation rate (after 20 minutes) of the obtained adhesive film was 76%.

(Comparative Example 3) 30 parts by weight of APP and THE
An adhesive film was produced in the same manner as in Example 2 except that IC was 40 parts by weight and titanium oxide was 5 parts by weight. The stress relaxation rate (after 20 minutes) of the obtained adhesive film was 66%.
Met.

Table 1 shows the results of evaluation of the adhesive films and tapes obtained in Examples 1 to 3 and Comparative Examples 1 to 3, which were subjected to a 90 ° peel test, a shear adhesive strength test and a flammability test.

[0057]

[Table 1]

The test method is as follows. 1. 90 ° peel test Adhesive tape was cut into 20mm width and 150mm length, and cut into 2
Width 25 mm, length 200 mm, thickness 2 under 3 ° C atmosphere
One side of the adhesive tape is attached to a stainless steel plate (# 304) having a thickness of 100 mm with an adhesive length of 100 mm, and a stainless foil (# 304) having a thickness of 50 μm is attached to the other side for backing. After making two round trips with the roller,
After 24 hours, using a tensile tester, 300 mm /
The 90 ° peel force was measured at a pulling speed of min.

2. Shear adhesive strength test Adhesive tape was cut into 20 mm × 20 mm, 23 ° C., 6
50mm × 50mm, thickness 2mm under 5% RH atmosphere
The pieces were attached in a sandwich shape between the two stainless steel plates (# 304) in No. 2 and pressed under a load of 5 kg for 15 minutes, and after 24 hours, the shear adhesive strength was measured at a pulling speed of 50 mm / min.

3. Flame retardance test The flammability was classified according to JIS D 1201.

Example 4 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.01 parts by weight of n-dodecanethiol, 2.2-dimethoxy-
0.1 parts by weight of 2-phenylacetophenone and high-density polyethylene fine particles having an average particle diameter of 20 μm (Mitsui Petrochemical Co., Ltd., trade name “Miperon XM-220”, specific gravity 0.9
20 parts by weight of 5), 10 parts by weight of APP, and 5 parts by weight of thermally expansive graphite (manufactured by Nippon Kasei Co., Ltd., trade name "CA60S") are uniformly mixed with stirring in a separable flask until a composition is obtained. After manufacturing, dissolved oxygen was removed by purging with nitrogen gas. Then, when the composition was irradiated with ultraviolet rays using a black light lamp, the monomers in the composition were polymerized to raise the temperature and simultaneously increase the viscosity. When the temperature of the composition increased by 5 ° C, the light irradiation was stopped. The partially polymerized thickened composition obtained as a result had a conversion of 3.7% and a viscosity of 2200 cps.

Furthermore, after 0.1 part by weight of hexanediol diacrylate was added, a film having a thickness of 1.0 at the end of the polymerization was formed on the release-treated surface of the 38 μm-thick PET film which was release-treated. Then, the same PET film was covered on the coated surface so that the release-treated surface was in contact with the coated surface. Irradiation intensity is 2mW from the top of this covered PET film using a chemical lamp.
The lamp height was adjusted so as to be / cm ^2, and irradiation was performed for 8 minutes to obtain an adhesive film. The residual monomer of this adhesive film was 0.1% or less, and the gel fraction was 95%. The stress relaxation rate (after 20 minutes) of this adhesive film is 70.
%Met.

(Example 5) n-butyl acrylate 85
Parts by weight, acrylic acid 15 parts by weight, hydrophilic silica (manufactured by Nippon Aerosil Co., Ltd., trade name "Aerosil 200") 3 parts by weight, APP 5 parts by weight, and heat-expandable graphite 8 parts by weight with a dissolver type stirrer for 4 hours at 1000 rpm. Stir and mix with
A viscous liquid was obtained. 50 parts by weight of glass balloons having an average particle size of 45 μm (trade name “CEL” manufactured by Asahi Glass Co., Ltd.
-STARZ-27 ", specific gravity 0.27), 0.1 part by weight of 2.2-dimethoxy-2-phenylacetophenone,
After 0.1 part by weight of hexanediol diacrylate was uniformly mixed with stirring, nitrogen gas was purged to remove dissolved oxygen. Hereinafter, in the same manner as in Example 4, an adhesive film having a thickness of 1.0 mm was obtained. The stress relaxation rate (after 20 minutes) of this adhesive film was 72%.

Example 6 70 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of isooctyl acrylate, 10 parts by weight of acrylic acid, 3 parts by weight of hydrophilic silica (trade name "Aerosil 200" manufactured by Nippon Aerosil Co., Ltd.), t
40 parts by weight of butylphosphonic acid (manufactured by Aldrich) and 2 parts by weight of thermally expandable graphite were mixed with a dissolver-type stirrer 4
The mixture was stirred and mixed at 1000 rpm for a time to obtain a viscous liquid.
50 parts by weight of a glass balloon having an average particle diameter of 45 μm (trade name “CEL-STARZ-2” manufactured by Asahi Glass Co., Ltd.
7 ", specific gravity 0.27), 0.1 parts by weight of 2.2-dimethoxy-2-phenylacetophenone and 0.1 parts by weight of hexanediol diacrylate were stirred and mixed until uniform, and then nitrogen gas was purged. , Dissolved oxygen was removed. Hereinafter, in the same manner as in Example 4, an adhesive film having a thickness of 1.0 mm was obtained. The stress relaxation rate (20
Minutes later) was 60%.

Separately, 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.05 parts by weight of n-dodecanethiol, 80 parts by weight of ethyl acetate, a stirrer, a reflux condenser, a thermometer, a dropping funnel and After charging into a five-necked flask equipped with a nitrogen gas inlet and stirring and dissolving to form a uniform mixture, nitrogen gas was purged for about 30 minutes,
The oxygen present in the monomer solution was removed. Then, the air in the flask was replaced with nitrogen gas, the temperature was raised with stirring, and this was kept at 70 ° C. to prepare a solution of 0.03 parts by weight of benzoyl peroxide dissolved in 1 part by weight of ethyl acetate. After dropping with a dropping funnel, a polymerization reaction was performed at the same temperature for 10 hours to obtain a copolymer solution. 2.4 parts by weight (based on 100 parts by weight of the copolymer) of ethyl acetate solution (trade name "Coronate L55E" manufactured by Nippon Polyurethane Industry Co., Ltd.) of trimethylolpropane tolylene diisocyanate adduct was added to the above copolymer solution. The mixture was added and uniformly mixed to prepare an adhesive solution. The pressure-sensitive adhesive solution is applied onto a separator so as to have a dry thickness of 50 μm and dried to produce a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is laminated on both sides of the pressure-sensitive adhesive film to form a pressure-sensitive adhesive tape. Got

Comparative Example 4 An adhesive film was obtained in the same manner as in Example 4, except that the phosphorus compound and the thermally expandable graphite were not added. The stress relaxation rate (2
0 minutes later) was 77%.

(Comparative Example 5) An adhesive tape was obtained in the same manner as in Example 6 except that 3 parts by weight of APP and 1 part by weight of thermally expandable graphite were used. Stress relaxation rate of the obtained adhesive tape (20
Minutes later) was 76%.

Comparative Example 6 An adhesive film was obtained in the same manner as in Example 5 except that APP was 30 parts by weight and the heat-expandable graphite was 20 parts by weight. The stress relaxation rate (after 20 minutes) of the obtained adhesive tape was 55%.

The adhesive tapes obtained in Examples 4 to 6 and Comparative Examples 4 to 6 were subjected to a 90 ° peel test, a shear adhesive strength test, and a flammability test, and the results are shown in Table 2.

[0070]

[Table 2]

(Example 7) 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.01 parts by weight of n-dodecanethiol, 2.2-dimethoxy-
0.1 parts by weight of phenylacetophenone, average particle size 2
High-density polyethylene fine particles of 0 μm (Mitsui Petrochemical Co., Ltd., trade name “Miperon XM-220”, specific gravity 0.95)
20 parts by weight, and 5 parts by weight of red phosphorus (manufactured by Rin Kagaku Kogyo Co., Ltd., trade name "NOVALED 120") were stirred and mixed in a separable flask until a composition was prepared, and then nitrogen gas was added. Purged to remove dissolved oxygen. Then, when the composition was irradiated with ultraviolet rays using a black light lamp, the monomers in the composition were polymerized to raise the temperature and simultaneously increase the viscosity. When the temperature of the composition increased by 5 ° C, the light irradiation was stopped. The partially polymerized thickened composition obtained as a result had a conversion of 3.7% and a viscosity of 2200 cps.
Met.

Further, 0.1 part by weight of hexanediol diacrylate was added, and then coated on a release-treated 38 μm-thick PET film so as to have a film thickness of 1.0 mm at the end of polymerization. Further, the same PET film was covered on this coated surface so that the release-treated surface was in contact with this coated surface. Irradiation intensity is ² mW / cm ² from the top of this covered PET film using a chemical lamp.
The height of the lamp was adjusted so as to obtain a pressure sensitive adhesive film, and irradiation was performed for 8 minutes to obtain an adhesive film. The residual monomer of this adhesive film was 0.1% or less, and the gel fraction was 95%. The stress relaxation rate (after 20 minutes) of this adhesive film was 70%.

(Example 8) N-butyl acrylate was added to 8
5 parts by weight, 15 parts by weight of acrylic acid, 3 parts of hydrophilic silica (product name "Aerosil 200" manufactured by Nippon Aerosil Co., Ltd.)
4 parts by weight, 60 parts by weight of APP with a dissolver stirrer
The mixture was stirred and mixed at 1000 rpm for a time to obtain a viscous liquid.
50 parts by weight of a glass balloon having an average particle diameter of 45 μm (trade name “CEL-STARZ-2” manufactured by Asahi Glass Co., Ltd.
7 ", specific gravity 0.27), 0.1 parts by weight of 2.2-dimethoxy-phenylacetophenone and 0.1 parts by weight of hexanediol diacrylate were stirred and mixed until uniform, then purged with nitrogen gas and dissolved. Oxygen was removed. Hereinafter, a pressure-sensitive adhesive film having a thickness of 1.0 mm was manufactured in the same manner as in Example 7. The stress relaxation rate (after 20 minutes) of this adhesive film was 60%.

(Example 9) 70 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of isooctyl acrylate, 10 parts by weight of acrylic acid, 3 parts by weight of hydrophilic silica (manufactured by Nippon Aerosil Co., Ltd., trade name "Aerosil 200"), A
6 parts by weight of PP and 5 parts by weight of red phosphorus were mixed by stirring with a dissolver type stirrer at 1000 rpm for 4 hours to obtain a viscous liquid. Add to this 5 glass balloons with an average particle size of 45 μm.
0 parts by weight (manufactured by Asahi Insulators Co., Ltd., trade name “CEL-STARZ-
27 ", specific gravity 0.27), 0.1 parts by weight of 2.2-dimethoxy-phenylacetophenone and 0.1 parts by weight of hexanediol diacrylate were stirred and mixed until uniform, and then nitrogen gas was purged to dissolve. Oxygen was removed.
Hereinafter, a pressure-sensitive adhesive film having a thickness of 1.0 mm was manufactured in the same manner as in Example 7. The stress relaxation rate (20
Minutes later) was 75%.

Separately, 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.05 parts by weight of n-dodecanethiol, 80 parts by weight of ethyl acetate, a stirrer, a reflux condenser, a thermometer, a dropping funnel and After charging into a five-necked flask equipped with a nitrogen gas inlet and stirring and dissolving to form a uniform mixture, nitrogen gas was purged for about 30 minutes,
Dissolved oxygen was removed. After that, the air in the flask was replaced with nitrogen gas, and the temperature was raised with stirring to 70 ° C.
A solution of 0.03 parts by weight of benzoyl peroxide dissolved in 1 part by weight of ethyl acetate was added dropwise with a dropping funnel, and the mixture was allowed to polymerize for 10 hours at the same temperature to obtain a copolymer solution. It was 2.4 parts by weight of an ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane (trade name "Coronate L55E" manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to the above solution of the copolymer (per 100 parts by weight of the solid content of the copolymer). Was added and mixed uniformly to prepare an adhesive solution. The pressure-sensitive adhesive solution is applied onto a separator so as to have a dry thickness of 50 μm and dried to produce a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is laminated on both sides of the pressure-sensitive adhesive film to form a pressure-sensitive adhesive tape. Was manufactured.

Comparative Example 7 An adhesive film was obtained in the same manner as in Example 7, except that APP and red phosphorus were not added. The stress relaxation rate (after 20 minutes) of the obtained adhesive film was 75%.

(Comparative Example 8) An adhesive film and a tape were obtained in the same manner as in Example 9 except that 2 parts by weight of APP and 0.5 part by weight of red phosphorus were used. The stress relaxation rate (after 20 minutes) of the obtained adhesive film was 76%.

(Comparative Example 9) An adhesive film was obtained in the same manner as in Example 8 except that 80 parts by weight of APP was used. The stress relaxation rate (after 20 minutes) of the obtained adhesive film was 66%.
Met.

The adhesive films and tapes obtained in Examples 7 to 9 and Comparative Examples 7 to 9 were subjected to a 90 ° peel test, a shear adhesive strength test and a flammability test, and the results are shown in Table 3.

[0080]

[Table 3]

[0081]

According to the present invention, the alkyl group has 4 to 1 carbon atoms.
Since the copolymer obtained by copolymerizing the alkyl (meth) acrylate of 4 and a monomer copolymerizable with the alkyl (meth) acrylate is molded into a film,
It becomes a good adhesive film. Furthermore, in the present invention, when the flame-retardant pressure-sensitive adhesive film has a stress relaxation rate of 50% or more after 20 minutes when stretched by 100%, even if there are relatively fine irregularities on the surface to be adhered, The film-like composition is deformed and adheres to the surface to be adhered,
In addition, the pressure-sensitive adhesive film has a large adhesive force because the stress at the time of peeling is spread and relaxed as a whole, so that peeling is difficult.

According to the invention of claim 1, as the flame retardant,
Since it contains ammonium polyphosphate, a special nitrogen-containing compound, and a metal oxide, it becomes a flame-retardant adhesive film which is not easily burned and is good. Further, in the invention of the second aspect, since the phosphorus compound and the heat-expandable graphite are contained as the flame retardant, it becomes a flame-retardant adhesive film which is hard to burn and is good. or,
According to the invention of claim 3, since ammonium polyphosphate and / or red phosphorus is contained as the flame retardant, a good flame-retardant adhesive film is obtained which is difficult to burn. in this way,
Since the inventions according to claims 1 to 3 do not contain halogen, no harmful smoke is generated at the time of combustion, there is no corrosiveness to equipment, and no harm to human bodies, and it is extremely useful.

In the invention according to claim 4, since the flame-retardant pressure-sensitive adhesive film contains fine particles or hollow fine particles of a special size, the stress relaxation rate increases,
It strongly adheres to the surface to be adhered with relatively fine unevenness,
In addition, the flame-retardant adhesive film does not easily peel off and is a good flame-retardant adhesive film. Further, according to the invention of claim 5, since the pressure-sensitive adhesive layer is provided on at least one surface, the flame-retardant pressure-sensitive adhesive tape has further improved adhesive strength.

Claims (5)

[Claims] 1. An alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms, and 100 parts by weight of a copolymer obtained by copolymerizing a vinyl monomer copolymerizable with the alkyl (meth) acrylate. A flame-retardant pressure-sensitive adhesive film obtained by molding a composition comprising ammonium phosphate, a nitrogen-containing compound represented by the following structural formula and a mixture of three components of a metal oxide in an amount of 5 to 70 parts by weight. A flame-retardant adhesive film having a stress relaxation rate of 50% or more after 20 minutes when the flame-retardant adhesive film is stretched 100%. Embedded image 2. An alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms, 100 parts by weight of a copolymer obtained by copolymerizing a vinyl monomer copolymerizable with the alkyl (meth) acrylate, and phosphorus. A flame-retardant pressure-sensitive adhesive film formed by film-forming a composition comprising 5 to 50 parts by weight of a compound and 2 to 15 parts by weight of heat-expandable graphite, when the flame-retardant pressure-sensitive adhesive film is stretched by 100%. The flame-retardant adhesive film having a stress relaxation rate of 50% or more after 20 minutes. 3. 100 parts by weight of a copolymer obtained by copolymerizing an alkyl (meth) acrylate having an alkyl group with 4 to 14 carbon atoms and a vinyl monomer copolymerizable with the alkyl (meth) acrylate, Ammonium phosphate 5
A flame-retardant pressure-sensitive adhesive film obtained by molding a composition comprising 70 parts by weight and / or 2 to 30 parts by weight of red phosphorus into a film shape, and 20 minutes when the flame-retardant pressure-sensitive adhesive film is stretched by 100%. A flame-retardant pressure-sensitive adhesive film having a stress relaxation rate of 50% or more. 4. An alkyl (meth) acrylate whose alkyl group has 4 to 14 carbon atoms and 100 parts by weight of a copolymer obtained by copolymerizing a vinyl monomer copolymerizable with the alkyl (meth) acrylate. Furthermore, the average particle size 1 to
0.5 to 175 for 150 μm fine particles or hollow fine particles
The flame-retardant pressure-sensitive adhesive film according to any one of claims 1 to 3, wherein the flame-retardant pressure-sensitive adhesive film is contained in an amount of 10 to 50 volume% by weight or volume fraction. 5. A flame-retardant pressure-sensitive adhesive tape, comprising an adhesive layer provided on at least one surface of the flame-retardant pressure-sensitive adhesive film according to claim 1.