JP4450419B2 - Flame retardant adhesive tape - Google Patents

Description

  The present invention has excellent flame retardancy and adhesive properties as well as carbonization breakdown without using halogen-based flame retardants that generate toxic halogen-containing gases during incineration and antimony oxide, which has been pointed out to have adverse effects on the human body. The present invention relates to a flame retardant pressure-sensitive adhesive tape for electrical insulation having tracking resistance and the like that can be satisfactorily suppressed.

  2. Description of the Related Art In recent years, high flame retardancy has been demanded in various industries in the electric and electronic fields for electric components and the like constituting the industry. Along with this, high flame retardance that passes various tests such as UL510 combustion test is also demanded in electrical insulating electronic tapes used for electrical and electronic parts, especially transformer insulation applications. In addition to high flame resistance, the electrical insulating adhesive tape has excellent electrical properties such as tracking resistance, dielectric breakdown voltage, and withstand voltage, electrolytic corrosion resistance, and is necessary for the application. High adhesive strength is required, and in order to satisfy these conditions, it is usually necessary to blend a halogen-based flame retardant having a high flame retardant effect and antimony oxide into the adhesive to make the adhesive tape flame retardant. It was general.

  However, halogen-based flame retardants have problems that generate toxic halogen-containing gases during incineration or corrode metals, and that antimony oxide has been pointed out to have adverse effects on the human body. Therefore, there is a demand for a flame-retardant pressure-sensitive adhesive tape for electrical insulation that does not use a halogen-based flame retardant and antimony oxide.

  As flame retardants other than halogen flame retardants, methods using metal hydroxide flame retardants such as aluminum hydroxide and magnesium hydroxide are known, but metal hydroxide flame retardants are halogen flame retardants. Since the flame retardant effect is much inferior to that, it has to be blended in a large amount in the pressure-sensitive adhesive, and there is a problem that the adhesive strength is lowered. In order to obtain the desired flame retardant effect with the metal hydroxide flame retardant content within the range that does not impair the adhesive properties, an aromatic polyamide base material that is difficult to burn is laminated (Patent Document 1), or flame retardant imparted It is necessary to separately provide an undercoat layer for the purpose (Patent Document 2), and there is a lack of versatility because an expensive base material is used or two adhesive coating steps are required. there were.

  As flame retardants other than halogen flame retardants and metal hydroxide flame retardants, nitrogen-containing compounds such as melamine cyanurate, triazine compounds, guanidine compounds, guanylurea compounds, melamine / formaldehyde resins are known. As with metal hydroxide flame retardants, the flame retardant effect is far inferior to that of halogen flame retardants. With a typical tape configuration, it has been difficult to satisfy all of flame retardancy, adhesive properties, electrical properties, and the like.

  In addition, phosphorus compounds are used which are not as flame retardant as halogen flame retardants but have a relatively high flame retardant effect. Among them, a combination of a phosphorus flame retardant containing a nitrogen element such as ammonium polyphosphate having a high flame retardant effect and red phosphorus has been proposed (Patent Document 3). There was a problem of generating harmful phosphine gas. In addition, highly polar (highly ionic) flame retardants such as ammonium polyphosphate and melamine polyphosphate may cause a decrease in tracking resistance and electrolytic corrosion resistance necessary for adhesive tapes for electrical insulation in some cases. Therefore (Non-Patent Document 1), when used for electrical insulation, only an amount within a limited range could be used.

  It is known to use a phosphate ester flame retardant as a phosphorus flame retardant other than the nitrogen-containing phosphorus compound, but when the property of the phosphate ester compound is liquid, the adhesive layer is plasticized. The cohesive strength is reduced, and the flame retardant bleeds on the surface of the pressure-sensitive adhesive layer. When the phosphate ester flame retardant is solid, the flame retardant is difficult on the surface of the pressure-sensitive adhesive layer. There is a problem that the fuel particles are precipitated (blooming phenomenon), and the adhesive properties and texture of the adhesive tape are impaired. Therefore, a microcapsulation of aromatic phosphate ester and phosphate ester flame retardant (Patent Document 4) to prevent precipitation of the flame retardant, combined use of phosphate ester flame retardant and melamine resin particles (patent Document 5), or a combination of an aromatic condensed phosphate ester and a phosphate ester (Patent Document 6) has been devised to obtain sufficient flame retardancy without using red phosphorus, but electrical insulation No particular mention is made of tracking resistance, an electrolytic corrosion coefficient, and the like, which are indispensable electrical characteristics.

  From the above background, in the field of electrical insulating pressure-sensitive adhesive tapes, it does not generate harmful halogen-containing gases during incineration, does not contain antimony oxide, which has been pointed out to have adverse effects on the human body, Adhesive properties with sufficient adhesive properties, dielectric breakdown voltage, withstand voltage, tracking resistance, and flame retardant properties that can pass the UL510 flammability test. Furthermore, there is no adhesion of flame retardant on the surface of the adhesive layer. Development of tape is desired.

JP 2002-121508 A JP 2003-96417 A JP-A-8-193187 JP 2000-169811 A JP-A-11-323268 JP-A-11-323269 Nishizawa Hitoshi, Plastics, Vol.54, No. 3 (2003)

  The present invention has excellent flame retardancy and adhesive properties without using halogen-based flame retardants that generate toxic halogen-containing gases during incineration or antimony oxide, which has been pointed out to have adverse effects on the human body, For electrical insulation that has both high electrical insulation and tracking resistance that can well suppress carbonization breakdown, and does not cause flame retardants to deposit on the surface of the adhesive layer or plasticize the adhesive layer. It is to provide a flame retardant adhesive tape.

As a result of intensive studies in order to solve such problems, the present inventor has obtained the following knowledge and completed the present invention.
Combining a phosphate ester flame retardant and a nitrogen-containing phosphate compound flame retardant together in an adhesive allows UL510 combustion test without generating harmful halogen-containing gas or phosphine gas during incineration. High flame retardant properties that pass the requirements, adhesive properties at a level that is not problematic for the application, high electrical insulation, and tracking resistance that can effectively suppress carbonization breakdown, etc., and dispersibility in adhesives Found that a good nitrogen-containing phosphate flame retardant can effectively prevent precipitation of the phosphate ester flame retardant on the pressure-sensitive adhesive layer surface due to its high affinity with the phosphate ester flame retardant, The invented flame-retardant pressure-sensitive adhesive tape of the present invention has been completed.

(1) Select from an aromatic phosphate ester flame retardant and an aromatic condensed phosphate ester flame retardant without using any halogen-based flame retardant, antimony-containing compound, and red phosphorus on at least one side of the substrate. At least one phosphate-based flame retardant selected from melamine pyrophosphate, melamine polyphosphate, and phosphate amide, a phosphate-based flame retardant The blending ratio of the flame retardant to the nitrogen-containing phosphate compound-based flame retardant is 1: 0.3 to 10, and the phosphate ester-based flame retardant with respect to 100 parts by mass of the adhesive base polymer made of a polymer polymerized in advance And a nitrogen-containing phosphate compound-based flame retardant is provided with a pressure-sensitive adhesive layer comprising a flame-retardant pressure-sensitive adhesive composition added in a range of 20 to 300 parts by mass. And flame retardant adhesive tape.
(2) The blending ratio of the phosphate ester flame retardant to the nitrogen-containing phosphate compound flame retardant is 1: 0.5 to 6, and the blending amount of the flame retardant in the flame retardant pressure-sensitive adhesive layer is as follows. The flame retardant adhesive tape according to (1) , wherein the amount of the flame retardant is 35 to 200 parts by mass with respect to 100 parts by mass of the adhesive base polymer .
(3) The flame-retardant adhesive tape according to (1) or (2), wherein at least one layer made of an electrically insulating material is provided as the base material.
(4) The flame-retardant pressure-sensitive adhesive tape according to any one of (1) to (3), which passes in UL510 [electrical insulation tape standard] combustion test.
(5) The difficulty described in any one of (1) to (3), wherein the comparative tracking index (CTI value) measured according to JIS C 2134 (IEC112) is 600 V or more. Flammable adhesive tape.
(6) The flame retardant adhesive tape according to any one of (1) to (3), wherein the flame retardant adhesive tape is for electrical insulation.

Since the flame-retardant adhesive tape for electrical insulation of the present invention does not contain a halogen-based flame retardant or red phosphorus, it does not generate harmful halogen-containing gas or phosphine gas even if incinerated, and has an adverse effect on the human body. Does not contain antimony oxide, which has been pointed out. Also, since it is not used with metal hydroxide flame retardants or nitrogen-containing compound flame retardants alone or in combination with low flame retardant effect, it is not necessary to add a large amount of flame retardant and without reducing the adhesive strength In addition, it has high flame retardancy that passes the UL510 combustion test. Furthermore, since a flame retardant having high polarity (high ionicity) such as ammonium polyphosphate or melamine polyphosphate is not used alone, there is no problem in electrical characteristics such as tracking resistance. By using an appropriate amount of the nitrogen-containing phosphate flame retardant, the compatibility between the phosphate ester flame retardant and the adhesive is improved, and the phosphate ester flame retardant precipitates on the surface of the adhesive layer, resulting in adhesive strength. Is not reduced or the texture of the adhesive tape is not impaired. In addition, since a large amount of liquid phosphate ester is not used, the pressure-sensitive adhesive layer is not plasticized to reduce the cohesive force. Since the solid phosphorus ester flame retardant alone is not mixed in a large amount, the flame retardant does not deteriorate on the surface of the pressure-sensitive adhesive layer and does not deteriorate the adhesive force or damage the texture of the pressure-sensitive adhesive tape.
Since the flame-retardant adhesive tape of the present invention is excellent in tracking resistance and flame retardancy, it can be used as an interlayer insulating adhesive tape to shorten the creepage distance of a power transformer, etc. It has the effects of heightening, capacity increasing, tubelessness, weight reduction and downsizing. The flame-retardant adhesive tape of the present invention is also excellent in high withstand voltage and storage characteristics. On the other hand, the comparative examples 1, 5 and 6 using the conventional flame retardant satisfy the requirement standard for flame retardancy, but the comparative tracking index cannot be set to 600 V or more. In Comparative Example 7 using the above flame retardant, there are some which satisfy the standard that the comparative tracking index is 600 V or more, but the flame retardant standard cannot be satisfied and cannot be used.

  The present invention uses a phosphoric ester-based flame retardant that may be deposited on the surface of the pressure-sensitive adhesive layer or plasticize the pressure-sensitive adhesive layer within a certain range, and has good dispersibility in the pressure-sensitive adhesive. Adhesive layer surface of phosphate ester flame retardant by using nitrogen-containing phosphate compound flame retardant with high affinity with ester flame retardant in combination with this in an amount that does not impair electrical properties Thus, it is possible to obtain a flame-retardant pressure-sensitive adhesive tape for electrical insulation that effectively prevents precipitation into the metal and satisfies all of the intended matters.

Hereinafter, the present invention will be described in more detail.
The flame-retardant pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive comprising a flame-retardant pressure-sensitive adhesive composition comprising a phosphate ester-based flame retardant and a nitrogen-containing phosphate compound-based flame retardant on at least one side of a substrate. It has a structure in which a layer is provided. Here, the flame retardant pressure-sensitive adhesive layer is made flame retardant by adding at least one phosphate ester flame retardant and at least one nitrogen-containing phosphate compound flame retardant, and has high flame retardancy. Excellent adhesion properties, electrical insulation, and tracking resistance that can effectively suppress carbonization breakdown, and flame retardants in the adhesive layer can be deposited on the surface of the adhesive layer even after a long time. Absent.
The flame-retardant pressure-sensitive adhesive layer is a state in which various flame retardants are uniformly dispersed in the pressure-sensitive adhesive base polymer by a mechanical kneading method.

  The flame-retardant pressure-sensitive adhesive tape of the present invention is provided with a flame-retardant pressure-sensitive adhesive layer on the substrate surface. Although the thickness of an adhesive layer is 5-100 micrometers normally, Preferably, it is about 10-60 micrometers.

In the flame-retardant pressure-sensitive adhesive tape of the present invention, the amount of the flame retardant contained in the flame-retardant pressure-sensitive adhesive layer is based on 100 parts by mass of the pressure-sensitive adhesive base polymer. The total amount of the flame retardant is in the range of 20 to 300 parts by mass. From the viewpoint of obtaining a good balance of the respective characteristics, the amount of the flame retardant per 100 parts by mass of the adhesive is preferably 35 to 200 parts by mass.
When the total amount of the flame retardant exceeds 300 parts by mass, it is advantageous for imparting flame retardancy, but the tracking resistance is reduced, the flame retardant is deposited on the pressure-sensitive adhesive layer surface, and the cohesive strength of the pressure-sensitive adhesive layer is reduced. Moreover, there is a risk of insufficient adhesive strength as an adhesive tape. On the other hand, when the blending amount is less than 20 parts by mass, the adhesive properties and the like are improved, but the flame retardancy is lowered, and in the UL510 combustion test, the flame retardance performance at an acceptable level may not be achieved.

  The blending ratio of the phosphate ester flame retardant to the nitrogen-containing phosphate compound flame retardant in the present invention is 1: 0.3 to 10, preferably 1: 0.5 to 6. If the ratio of the phosphate ester flame retardant becomes too high, the adhesive layer may be plasticized or the phosphate ester flame retardant may be deposited on the adhesive layer surface, while the nitrogen-containing phosphate compound. If the ratio of the flame retardant is too high, the tracking resistance, which is one of the important characteristics as an adhesive tape for electrical insulation, may be reduced.

  The phosphate ester flame retardant used in the present invention is not particularly limited, but aliphatic phosphate esters such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl Aromatic phosphates such as diphenyl phosphate, trixylenyl phosphate, cresyl 2,6 xylenyl phosphate, tris (t-butylated phenyl) phosphate, tris (isopropylated phenyl) phosphate, triaryl isopropylated phosphate, resorcinol Examples thereof include aromatic condensed phosphates such as bisdiphenyl phosphate, bisphenol A bis (diphenyl phosphate), and resorcinol bisdixylenyl phosphate. Preferably, it is a solid aromatic monomer type or an aromatic condensed phosphate ester that hardly reduces the cohesive strength of the pressure-sensitive adhesive layer. From the viewpoint of improving compatibility with the pressure-sensitive adhesive, an aromatic condensed phosphate ester into which an alkyl group has been introduced is more preferable. These phosphate ester flame retardants may be used singly or in combination of two or more.

  The nitrogen-containing phosphate compound-based flame retardant used in the present invention is not particularly limited, but ammonium polyphosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, melamine polyphosphate, melam polyphosphate, melem polyphosphate, polyphosphorus Examples include acid melon, phosphate ester amide, and guanidine phosphate. These nitrogen-containing phosphate compounds can be used alone or in combination with a phosphate ester flame retardant using two or more. These nitrogen-containing phosphate compound-based flame retardants have high affinity (familiarity) with phosphate ester-based flame retardants and high dispersibility in adhesives, so nitrogen-containing phosphate compound-based flame retardants It has been found that the addition of can effectively prevent precipitation of the phosphate ester flame retardant on the pressure-sensitive adhesive layer surface.

In the combination of the phosphate ester flame retardant and the nitrogen-containing phosphate flame retardant, the metal hydroxide, melamine compound, triazine compound, guanidine compound, guanyl are used as a combination component within a range not impairing the effect of the present invention. It can be added using at least one compound selected from a urea compound, dicyandiamide, and a boric acid compound.
Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, calcium hydroxide and the like.
Examples of the melamine compound include melamine sulfate, melamine nitrate, melamine borate, melamine phthalate, melamine sulfamate, and melamine cyanurate.
Although the addition amount of a combined use component is 0-80 mass parts with respect to 100 mass parts of adhesive base polymers, Preferably, it is 0-60 mass parts.

  Moreover, you may add to a combination of the said flame retardant 1 type, or 2 or more types of flame retardant adjuvants. Specific examples include zinc oxide, lead sulfide, tin oxide, zinc stannate, zinc borate and the like.

  The average particle size of the flame retardant other than the phosphate ester flame retardant and the flame retardant aid mentioned in the present invention is 0.5 to 25 μm, preferably 1 to 10 μm. If it is smaller than 0.5 μm, handling as a powder becomes inconvenient, and if it is larger than 25 μm, it tends to cause surface roughness due to stability problems after being dispersed in the pressure-sensitive adhesive and exposure to the surface of the pressure-sensitive adhesive layer. There is a difficulty that causes a decrease in adhesive strength.

  Although the adhesive used for this invention is not specifically limited, The well-known acrylic adhesive and rubber adhesive which are generally used are used as a base polymer. For example, as the acrylic pressure-sensitive adhesive, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Mainly composed of (meth) acrylic acid ester monomers such as (meth) acrylic acid isooctyl, (meth) acrylic acid nonyl, (meth) acrylic acid isononyl, etc., and (meth) acrylic acid, crotonic acid, fumaric acid, itaconic acid , A monomer containing a functional group such as maleic anhydride, vinyl acetate, acrylonitrile, styrene, 2-hydroxyethyl (meth) acrylate, 2-methylolethylacrylamide, and the like, which are obtained by copolymerization as necessary. It is an acrylic adhesive.

  The rubber-based pressure-sensitive adhesive of the present invention is not particularly limited. For example, one or more elastomer components such as natural rubber, styrene butadiene rubber, butyl rubber, isoprene rubber, butadiene rubber, and styrene / isoprene block copolymer are used. Rosin resin, terpene resin, aliphatic petroleum resin, aromatic petroleum resin, copolymer petroleum resin, alicyclic petroleum resin, coumarone / indene resin, pure monomer resin, It is a known rubber-based pressure-sensitive adhesive obtained by mixing a phenol-based resin, a xylene resin, or the like.

  In the case of an acrylic adhesive, the adhesive base polymer is a crosslinking agent such as an isocyanate compound, an acid anhydride, an amine compound, an epoxy compound, a metal chelate, an aziridine compound, and the rubber adhesive is , Reactive phenolic resins, sulfur compounds such as sulfur and thiurams, and vulcanizing agents such as maleimide, which are cross-linked or vulcanized, can be used to plasticize adhesive layers with liquid phosphate ester flame retardants Can be reduced, which is preferable.

  In the pressure-sensitive adhesive, various additives such as an antioxidant, a weathering agent, a softening agent, a stabilizer, a filler, a bulking agent, and a reinforcing agent may be used as long as the flame-retardant effect of the present invention is not impaired. One or a combination of two or more additives can be added.

  Although the base material used for the flame-retardant pressure-sensitive adhesive tape of the present invention is not particularly limited, a base material provided with at least one layer made of an electrically insulating material is preferable. Examples of materials that can be used for electrical insulation include film base materials such as polyester, polypropylene, polyethylene, polyphenylene sulfide, polyimide, polyamide, polyphenylene sulfide, polyacetate, polyetheretherketone, glass cloth, acetate cloth, etc. Examples thereof include a cloth base material, an aromatic polyamide non-woven fabric or a paper base material. These simple substance or what combined 2 or more types can be used. Moreover, the base material which laminated | stacked paper, cloth, the nonwoven fabric, etc. with the adhesive or the adhesive agent etc. as needed with respect to the said base material is used.

  The method for producing the flame retardant pressure-sensitive adhesive composition used in the present invention is not particularly limited, but as a method for dispersing the flame retardant into the pressure-sensitive adhesive base polymer, in addition to the generally known mechanical kneading dispersion method. In addition, a known method such as a solvent dispersion method or an ultrasonic dispersion method can be used as necessary. The coating method of the flame retardant pressure-sensitive adhesive composition produced in this way is not particularly limited. For example, one layer or two layers on at least one side of the substrate using a roll coater or a reverse coater. The flame-retardant pressure-sensitive adhesive tape of the present invention is obtained by applying more than one layer and heating as necessary.

  The function as a flame-retardant adhesive tape of the present invention is a risk of being ignited by high temperatures inside the various devices or animal heat when used in various fields such as electricity, electronics, OA equipment, home appliances, aircraft, ships and vehicles. It has a function to extinguish quickly even if it ignites, has little change over time, and has sufficient adhesive strength to withstand heat and the like. Moreover, both carbonized dielectric breakdown along the surface and carbonized dielectric breakdown in the thickness direction can be satisfactorily suppressed even at a high applied voltage of 600 V in an environment of contamination and moisture.

  In addition, when recycling various equipment parts after completing its role, halogen-containing gases and phosphine gases containing toxic chlorine and bromine that are undesirable for the environment and human body due to thermal decomposition even if incinerated as waste It has the feature which does not generate etc.

  The flame retardant mechanism of the flame retardant used in the flame retardant pressure-sensitive adhesive tape of the present invention is as follows: (1) The radical generated by the thermal decomposition of the phosphorus-containing compound flame retardant in the present invention is a base material and a pressure-sensitive adhesive composition. (2) From the dehydration carbonization reaction by the production of phosphoric acid and polyphosphoric acid by thermal decomposition of the phosphorus-containing compound flame retardant of the present invention. , An effect of forming a molten glassy surface layer or a dense carbonized film layer (char) on the surface of the adhesive tape and blocking from heat and oxygen to prevent flame expansion, (3) Further, in the present invention, nitrogen-containing phosphoric acid Since salt compound is an essential component, it is a flame retardant mechanism due to the effect of generating a thermal expansion type carbonized film by generating inert nitrogen gas, etc., creating a porous heat insulation layer, and further improving the flame retardant effect. .

  The flame-retardant pressure-sensitive adhesive tape of the present invention has a high degree of flame retardancy and excellent adhesive properties, and has both high dielectric breakdown voltage and withstand voltage, carbonization breakdown along the surface, and carbonization breakdown in the thickness direction. Since it has all the characteristics such as tracking resistance that can be satisfactorily suppressed, it is preferably used for insulation of electrical and electronic parts, particularly for insulation of transformers, but other uses that require flame retardancy, such as It can also be used for exteriors of electrical products, building materials, automobile parts, and curing at the site of handling fire.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” indicate “parts by mass” and “% by mass”.

<Preparation of adhesive>
75 parts of butyl acrylate, 20 parts of 2-ethylhexyl acrylate, 4.5 parts of acrylic acid, 0.5 part of 2-hydroxyethyl acrylate, and 1 part of benzoyl peroxide as a polymerization initiator are dissolved in ethyl acetate. The mixture was reacted at 0 ° C. for 5 hours, and the solid content was diluted to 40% to prepare an acrylic acid ester copolymer liquid (hereinafter referred to as an acrylic pressure-sensitive adhesive) having a weight average molecular weight of about 600,000.

Reference Example 1 15 parts of aromatic condensed phosphate ester flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.) with respect to 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, aromatic condensed phosphoric acid 20 parts of an ester-based flame retardant (trade name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.) and 30 parts of ammonium polyphosphate (trade name: Terrage C60, manufactured by Chisso Corporation) were added to a mixing and kneading machine (HM-3D-5). Kneaded with a special machine industry), and 2.5 parts of polyisocyanate crosslinking agent and an appropriate amount of organic solvent are added to the pressure-sensitive adhesive composition obtained by sufficiently dispersing, and stirred well until uniform. The pressure-sensitive adhesive layer coating solution thus obtained was applied to the easy-adhesive surface of the polyester film 25 μm that had been subjected to the easy adhesion treatment and the back surface release treatment in advance so that the thickness of the pressure-sensitive adhesive layer after drying was 25 to 35 μm. Dried and difficult of the present invention To obtain a sexual adhesive tape.

Example 2
15 parts of aromatic condensed phosphate ester flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.), aromatic condensed phosphate ester difficult for 100 parts solid content of the acrylic pressure-sensitive adhesive prepared above 20 parts of a flame retardant (trade name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.) and 30 parts of melamine polyphosphate (trade name: MPP-A, manufactured by Sanwa Chemical Co., Ltd.) were added and mixed and kneaded (HM-3D-5). Kneaded with a special machine industry), and 2.5 parts of polyisocyanate crosslinking agent and an appropriate amount of organic solvent are added to the pressure-sensitive adhesive composition obtained by sufficiently dispersing, and stirred well until uniform. The pressure-sensitive adhesive layer coating solution thus obtained was applied to the easy-adhesive surface of the polyester film 25 μm that had been subjected to the easy adhesion treatment and the back surface release treatment in advance so that the thickness of the pressure-sensitive adhesive layer after drying was 25 to 35 μm. After drying, the flame retardant adhesive tape of the present invention It was obtained.

Example 3
15 parts of aromatic phosphate ester flame retardant (trade name: TPP manufactured by Daihachi Chemical Industry Co., Ltd.), aromatic condensed phosphate ester flame retardant (product) Name: CR-741 Daihachi Chemical Industry Co., Ltd. (20 parts) and polyphosphate melamine (trade name: MPP-A, Sanwa Chemical Co., Ltd.) (30 parts) were added and mixed and kneaded (HM-3D-5 special machine) It is obtained by adding 2.5 parts of polyisocyanate-based crosslinking agent and an appropriate amount of organic solvent to the pressure-sensitive adhesive composition obtained by kneading with Kogyo Co., Ltd. The pressure-sensitive adhesive layer coating solution was applied and dried so that the thickness of the pressure-sensitive adhesive layer after drying was 25 to 35 μm on the easy-adhesive surface of the polyester film 25 μm that had been subjected to easy adhesion treatment and back surface release treatment in advance. The flame-retardant pressure-sensitive adhesive tape of the present invention was obtained.

Example 4
15 parts of aromatic phosphate ester flame retardant (trade name: TPP manufactured by Daihachi Chemical Industry Co., Ltd.), aromatic condensed phosphate ester flame retardant (product) Name: CR-741 20 manufactured by Daihachi Chemical Industry Co., Ltd., 30 parts melamine polyphosphate (trade name: MPP-A Sanwa Chemical Co., Ltd.), aluminum hydroxide (trade name: Heidilite H-42M Showa Denko ) 20 parts is added, kneaded with a mixing and kneading machine (HM-3D-5 Special Machine Industries Co., Ltd.), and 2.5 parts of polyisocyanate crosslinking agent is added to the pressure-sensitive adhesive composition obtained by sufficiently dispersing. , And an adhesive layer coating solution obtained by sufficiently stirring until an appropriate amount of organic solvent is added, and dried to an easily adhesive surface of a polyester film 25 μm that has been subjected to an easy adhesion treatment and a back surface release treatment in advance. The thickness of the adhesive layer after And coating and drying so that the 5 to 35 m, to obtain a flame-retardant adhesive tape of the present invention.

Comparative Example 1
40 parts of brominated flame retardant [tetrabromo bisphenol A derivative] (trade name: Fireguard 3000 manufactured by Teijin Chemicals Ltd.) and 25 parts of antimony trioxide are added to 100 parts of the solid content of the acrylic adhesive prepared above. Then, kneading with a mixing and kneading machine (HM-3D-5 manufactured by Tokushu Kika Kogyo Co., Ltd.) and fully dispersing the pressure-sensitive adhesive composition in 2.5 parts of a polyisocyanate crosslinking agent and an appropriate amount of organic A pressure-sensitive adhesive layer coating solution obtained by adding a solvent and sufficiently stirring until uniform becomes a pressure-sensitive adhesive layer after drying on an easy-adhesive surface of a polyester film 25 μm that has been subjected to an easy-adhesion treatment and a back surface release treatment in advance. The film was applied and dried so as to have a thickness of 25 to 35 μm to obtain a flame retardant adhesive tape.

Comparative Example 2
For 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, 65 parts of an aromatic phosphate ester flame retardant (trade name: TPP manufactured by Daihachi Chemical Industry Co., Ltd.), 2.5 parts of a polyisocyanate-based crosslinking agent, Then, the adhesive layer coating solution obtained by adding an appropriate amount of organic solvent and stirring sufficiently until uniform is dried on the easy-adhesive surface of the polyester film 25 μm that has been subjected to easy-adhesion treatment and back-side release treatment in advance. It applied and dried so that the thickness of the subsequent adhesive layer might be set to 25-35 micrometers, and the flame-retardant adhesive tape was obtained.

Comparative Example 3
For 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, 65 parts of an aromatic condensed phosphate ester flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.), 2. 5 parts and an appropriate amount of an organic solvent is added, and the pressure-sensitive adhesive layer coating solution obtained by sufficiently stirring until uniform is easily adhered to a polyester film 25 μm that has been subjected to an easy adhesion treatment and a back surface release treatment in advance. It applied and dried so that the thickness of the adhesive layer after drying might be set to 25-35 micrometers on the surface, and the flame-retardant adhesive tape was obtained.

Comparative Example 4
To 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, 65 parts of an aromatic condensed phosphate ester flame retardant (trade name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.), 2. 5 parts and an appropriate amount of an organic solvent is added, and the pressure-sensitive adhesive layer coating solution obtained by sufficiently stirring until uniform is easily adhered to a polyester film 25 μm that has been subjected to an easy adhesion treatment and a back surface release treatment in advance. It applied and dried so that the thickness of the adhesive layer after drying might be set to 25-35 micrometers on the surface, and the flame-retardant adhesive tape was obtained.

Comparative Example 5
65 parts of ammonium polyphosphate (trade name: Exolit AP423, manufactured by Quarian Japan Co.) is added to 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, and a mixing and kneading machine (HM-3D-5 special machine) It is obtained by adding 2.5 parts of polyisocyanate-based crosslinking agent and an appropriate amount of organic solvent to the pressure-sensitive adhesive composition obtained by kneading with Kogyo Co., Ltd. The pressure-sensitive adhesive layer coating solution was applied and dried so that the thickness of the pressure-sensitive adhesive layer after drying was 25 to 35 μm on the easy-adhesive surface of the polyester film 25 μm that had been subjected to easy adhesion treatment and back surface release treatment in advance. A flame retardant adhesive tape was obtained.

Comparative Example 6
65 parts of melamine polyphosphate (trade name: MPP-A manufactured by Sanwa Chemical Co., Ltd.) is added to 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, and a mixing and kneading machine (HM-3D-5 special machine) Obtained by kneading with Kako Kogyo Co., Ltd. and thoroughly dispersing it, adding 2.5 parts of a polyisocyanate-based crosslinking agent and an appropriate amount of an organic solvent and stirring thoroughly until uniform. The pressure-sensitive adhesive layer coating solution was applied and dried on the easy-adhesive surface of the polyester film 25 μm that had been subjected to easy-adhesion treatment and backside release treatment so that the thickness of the adhesive layer after drying would be 25-35 μm. Thus, a flame retardant adhesive tape was obtained.

Comparative Example 7
100 parts of aluminum hydroxide (trade name: Heidilite H-42M, manufactured by Showa Denko KK) is added to 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, and a mixing and kneading machine (HM-3D-5 special) Kneaded by Kika Kogyo Co., Ltd.) and 2.5 parts of polyisocyanate-based crosslinking agent and an appropriate amount of organic solvent are added to the pressure-sensitive adhesive composition obtained by sufficiently dispersing, and stirred well until uniform. The obtained pressure-sensitive adhesive layer coating solution is applied and dried so that the pressure-sensitive adhesive layer after drying has a thickness of 25 to 35 μm on the easy-adhesive surface of the polyester film 25 μm that has been subjected to easy adhesion treatment and backside release treatment. Thus, a flame retardant adhesive tape was obtained.

〔Test method〕
As described above, various properties of the tape samples obtained as the examples and comparative examples were tested and evaluated by the following methods. The results are shown in [Table 1].

[Adhesive strength] Measured according to JIS Z 0237.

[Retention force] Measured according to JIS Z 0237. However, the distance to which the tape is displaced is measured in 30 minutes under the conditions of a load area of 10 mm × 20 mm, a load of 300 g, and a temperature of 120 ° C., and the tape displacement distance is 20 mm or more. When the sample fell, it was recorded as “falling”.

[Tack] Measured according to JIS Z 0237.

[Dielectric breakdown voltage] The voltage at the time of dielectric breakdown was measured according to JIS C2107.

[Withstand voltage] In accordance with JIS C 2107, it was examined whether or not it could withstand a predetermined voltage for 1 minute.

[Comparative Tracking Index] Measured according to JIS C 2134 (IEC112).

[Number of electrolytic corrosion systems] Measured according to JIS C 2107 [Electrolytic corrosion by electric wire tensile strength method].

[Combustion test] A combustion test was performed according to UL510 [electrical insulation tape standard] combustion test.

[Appearance] The flame-retardant pressure-sensitive adhesive tapes produced in Examples and Comparative Examples were evaluated by visually observing the presence or absence of flame retardant precipitation (blooming phenomenon) on the surface of the pressure-sensitive adhesive layer.

[Generation of Halogen Gas] Measured by ion chromatography according to JIS K2541 (oxygen flask method), it was considered that halogen gas was generated when the detected amount of halogen ions exceeded 100 ppm.

  As is clear from Table 1, the flame-retardant pressure-sensitive adhesive tape for electrical insulation of the present invention satisfies all of the pressure-sensitive adhesive properties, electrical properties, and flame resistance required for the application, and flame retardant particles are deposited on the surface of the pressure-sensitive adhesive layer. Neither does it reduce the cohesive strength of the pressure-sensitive adhesive layer. Further, since no halogen-based flame retardant or red phosphorus is used, no harmful halogen-containing gas or phosphine gas is generated.

Claims (6)

At least one selected from an aromatic phosphate ester flame retardant and an aromatic condensed phosphate ester flame retardant without using any of a halogen flame retardant, an antimony-containing compound, and red phosphorus on at least one side of the substrate. One phosphate ester flame retardant and at least one nitrogen-containing phosphate compound flame retardant selected from melamine pyrophosphate, melamine polyphosphate, and phosphate ester amide, Phosphoric acid ester flame retardant and nitrogen content with respect to 100 parts by mass of the pressure-sensitive adhesive base polymer comprising a polymer previously polymerized at a blending ratio of the containing phosphate compound flame retardant of 1: 0.3-10 wherein the total amount of the phosphate compound-based flame retardant is provided an adhesive layer made of the flame-retardant adhesive composition was added in an amount of 20 to 300 parts by weight Retardant adhesive tape. The blending ratio of the phosphate ester-based flame retardant to the nitrogen-containing phosphate compound-based flame retardant is 1: 0.5 to 6, and the blending amount of the flame retardant in the flame retardant pressure-sensitive adhesive layer is based on the pressure-sensitive adhesive base. The flame retardant pressure-sensitive adhesive tape according to claim 1 , wherein the total amount of the flame retardant is 35 to 200 parts by mass with respect to 100 parts by mass of the polymer.   The flame-retardant pressure-sensitive adhesive tape according to claim 1, wherein at least one layer made of an electrically insulating material is provided as the base material.   The flame-retardant pressure-sensitive adhesive tape according to any one of claims 1 to 3, which passes the UL 510 [electrical insulation tape standard] combustion test.   The flame-retardant adhesive tape according to any one of claims 1 to 3, wherein a comparative tracking index (CTI value) measured according to JIS C 2134 (IEC112) is 600 V or more.   The flame-retardant pressure-sensitive adhesive tape according to claim 1, wherein the flame-retardant pressure-sensitive adhesive tape is for electrical insulation.