JP2006219565A - Flame-retardant adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a flame-retardant adhesive tape that has all properties of high flame retardance, excellent adhesion properties, high electrical insulating properties and tracking resistance of excellently controlling carbonization dielectric breakdown and does not cause precipitation of a flame retardant (blooming phenomenon) on the surface of an adhesive layer without using a halogen-based flame retardant and an antimony-containing compound. <P>SOLUTION: The flame-retardant adhesive tape is obtained by providing at least one side of a substrate with an adhesive layer composed of a flame-retardant adhesive composition prepared by adding 20-300 parts by mass of a phosphoric acid ester-based flame retardant and 5-50 parts by mass of an aromatic-containing tackifier resin to 100 parts by mass of an adhesive base polymer without intentionally adding a halogen compound and an antimony compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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, 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 and 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 far 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 much inferior to halogen flame retardants, so it is necessary to add a large amount. 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 that are not as flame retardant as halogen flame retardants but have a relatively high flame retardant effect are used. 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 force 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 inventors have obtained the following knowledge and completed the present invention.
Passes the UL510 combustion test without generating harmful halogen-containing gas and phosphine gas at the time of incineration by using a phosphate ester flame retardant and an aromatic-containing tackifying resin in combination in the adhesive. High flame retardancy, adhesive properties at a level that is not problematic for the application, high electrical insulation, tracking resistance that can effectively suppress carbonization breakdown, etc., and fragrance with good compatibility with adhesives Group-containing tackifier resin has the same aromatic structure as phosphate ester flame retardants in terms of molecular structure, so it is effective to deposit phosphate ester flame retardants on the adhesive layer surface due to their high affinity Thus, the present inventors have found that the flame retardant pressure-sensitive adhesive tape for electrical insulation of the present invention has been completed.

The present invention includes the following inventions.
(1) Flame retardancy in which 20 to 300 parts by mass of a phosphoric ester-based flame retardant and 5 to 50 parts by mass of an aromatic-containing tackifying resin are added to 100 parts by mass of an adhesive base polymer on at least one surface of a substrate. A flame-retardant pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition.
(2) The flame retardant adhesive tape according to (1), wherein the phosphate ester flame retardant is an aromatic phosphate ester flame retardant.
(3) The aromatic-containing tackifying resin is at least one selected from styrene-based resins, xylene-based resins, aromatic-containing terpene resins, and aromatic-containing petroleum resins, (1) or The flame-retardant adhesive tape according to (2).
(4) The flame-retardant adhesive tape according to any one of (1) to (3), wherein at least one layer made of an electrically insulating material is provided as the base material.
(5) The flame-retardant pressure-sensitive adhesive tape according to any one of (1) to (4), which passes in a UL510 [electrical insulation tape standard] combustion test.
(6) The difficulty described in any one of (1) to (5), wherein the comparative tracking index (CTI value) measured according to JIS C 2134 (IEC112) is 600 V or more. Flammable adhesive tape.
(7) The flame retardant adhesive tape according to any one of (1) to (6), 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. In addition, since it is not used with a metal hydroxide flame retardant or a nitrogen-containing compound flame retardant having a low flame retardant effect or a combination thereof, 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 highly polar (high ionic) flame retardant such as ammonium polyphosphate or melamine polyphosphate is not used, there is no problem in electrical characteristics such as tracking resistance. By using an aromatic-containing tackifying resin, the compatibility of the phosphate ester flame retardant and the adhesive is improved, and the phosphate ester flame retardant is deposited on the surface of the adhesive layer to reduce the adhesive strength. 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 large quantities, the flame retardant is not deposited on the surface of the pressure-sensitive adhesive layer, so that the adhesive strength is not lowered and the texture of the pressure-sensitive adhesive tape is not impaired.
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 effect of reducing the height, increasing the capacity, reducing the tube, reducing the weight, and reducing the size. Moreover, the flame-retardant pressure-sensitive adhesive tape of the present invention is excellent in high withstand voltage and storage characteristics. On the other hand, the comparative example 1 using the conventional flame retardant satisfies the requirement standard for flame retardancy, but the comparative tracking index cannot be 600 V or more, and the conventional flame retardant is not used. Some of the comparative examples 7 used satisfy the standard that the comparative tracking index is 600 V or more, but cannot satisfy the flame retardance standard and cannot be used.
The present invention uses, within a certain range, an aromatic-containing phosphate ester-based flame retardant that may be deposited on the surface of the adhesive layer or plasticize the adhesive layer. By using in combination with an aromatic-containing tackifying resin having miscibility with both the flame retardant and the pressure-sensitive adhesive base polymer, the flame retardant is effectively prevented from depositing on the surface of the pressure-sensitive adhesive layer. A flame-retardant pressure-sensitive adhesive tape for electrical insulation that satisfies all requirements is obtained.

Hereinafter, the present invention will be described in more detail.
The flame-retardant pressure-sensitive adhesive tape of the present invention is provided with a pressure-sensitive adhesive layer comprising a flame-retardant pressure-sensitive adhesive composition comprising a phosphate ester-based flame retardant and an aromatic-containing tackifier resin on at least one surface of a substrate. Has the structure. Here, the flame retardant pressure-sensitive adhesive layer has been made flame retardant by adding at least one phosphate ester flame retardant, and has high flame resistance and excellent adhesive properties, electrical insulation, and carbonized insulation. It has tracking resistance, etc. that can suppress destruction well, and by adding an aromatic-containing tackifying resin, the flame retardant in the adhesive layer does not deposit on the surface of the adhesive layer even if it elapses for a long time. .
The flame retardant pressure-sensitive adhesive layer is a state in which the flame retardant and the aromatic-containing tackifying resin are uniformly dispersed in the pressure-sensitive adhesive base polymer.

  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.

  The blending amount of the flame retardant in the flame retardant pressure-sensitive adhesive layer in the flame retardant pressure-sensitive adhesive tape of the present invention is such that the phosphate ester flame retardant is in the range of 20 to 300 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive base polymer. is there. 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 50 to 200 parts by mass. When the amount of the flame retardant exceeds 300 parts by mass, it is advantageous for imparting flame retardancy. However, precipitation of the flame retardant on the surface of the pressure-sensitive adhesive layer, reduction in cohesive strength of the pressure-sensitive adhesive layer, and further as a pressure-sensitive adhesive tape There is a risk of insufficient adhesion. In addition, when the blending amount is less than 20 parts by mass, the adhesive properties and the like are improved, but the flame retardant properties are lowered, and in the UL510 combustion test, it may not be possible to achieve an acceptable level of flame retardant performance.

  The blending amount of the aromatic-containing tackifying resin in the present invention is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the adhesive base polymer. If the amount of the aromatic-containing tackifying resin is too large, the low-temperature characteristics of the tape may be lowered or the flame retardancy may be reduced. On the other hand, if the amount is too small, phosphoric acid on the surface of the pressure-sensitive adhesive layer There is a risk that precipitation of the ester flame retardant cannot be prevented.

  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.

In addition, the phosphoric ester-based flame retardant includes metal hydroxide, melamine compound, triazine compound, guanidine compound, guanylurea compound, dicyandiamide, and boric acid compound as combined components within a range not impairing the effects of the present invention. It can add using the at least 1 sort (s) of compound chosen from.
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.

  As the flame retardant, one kind of flame retardant aid or a combination of two or more kinds may be used. 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. When it is smaller than 0.5 μm, handling as a powder becomes inconvenient, and when 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.

  The aromatic-containing tackifying resin used in the present invention is not particularly limited, but styrene resin, xylene resin, aromatic modified terpene resin, terpene phenol resin, aromatic petroleum resin, aliphatic aromatic petroleum resin, Coumarone-indene resin, phenolic resin, disproportionated rosin resin, rosin-modified phenolic resin, and the like. Among these aromatic-containing tackifying resins, the aromatic ester content is particularly high, and the phosphoric ester-based flame retardant having a high aromatic content has a high affinity, and is generally used for adhesives. Styrenic resins, xylene resins, aromatic-containing terpene resins, and aromatic-containing petroleum resins are preferred. These aromatic-containing tackifying resins can be used singly or in combination of two or more.

  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, acrylic adhesives include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth ) Mainly composed of (meth) acrylic acid ester monomers such as isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, and (meth) acrylic acid, crotonic acid, fumaric acid, itaconic acid, ( Anhydrous) known acrylics obtained by copolymerizing monomers containing functional groups such as maleic acid, vinyl acetate, acrylonitrile, styrene, 2-hydroxyethyl (meth) acrylate, 2-methylolethyl acrylamide, etc. as necessary Type 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 one or two or more types of tackifiers such as phenolic resins and xylene resins. Among these, rubber-based adhesives comprising a combination of aromatic-containing elastomers such as styrene-butadiene rubber and styrene / isoprene block copolymer and aromatic-containing tackifying resins such as aromatic-modified terpene resins and aromatic petroleum resins are aromatic. This is preferable for preventing precipitation of the group condensed phosphate ester flame retardant on the pressure-sensitive adhesive layer surface.

  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.

Further, in the pressure-sensitive adhesive, various additives such as an antioxidant, a weathering agent, a softening agent, a stabilizer, a filler, a bulking agent, a reinforcing agent and the like are included in the range not impairing the flame retardant effect of the present invention. 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 carbonization breakdown along the surface and carbonization breakdown in the thickness direction can be satisfactorily suppressed even at an applied voltage as high as 600 V in a contaminated or humid environment.

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

  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. This is a flame retarding mechanism due to the effect of generating a molten glass-like surface layer or a dense carbonized film layer (char) on the surface of the adhesive tape and blocking it from heat or oxygen to prevent flame expansion.

  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.

Example 1
30 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 50 parts of flame retardant (trade name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.), 25 parts of xylene resin (Nikanol HP-100, manufactured by Nippon Gas Chemical Co., Ltd.), 2.5 parts of polyisocyanate-based crosslinking agent, and appropriate amount of organic solvent The pressure-sensitive adhesive layer coating solution obtained by sufficiently stirring until uniform is added to 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 coated and dried so that thickness might be set to 25-35 micrometers, and the flame-retardant adhesive tape of this invention was obtained.

Example 2
For 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above, 40 parts of an aromatic phosphate ester flame retardant (trade name: TPP manufactured by Daihachi Chemical Industry Co., Ltd.), an aromatic condensed phosphate ester flame retardant (product) Name: CR-741 Daihachi Chemical Industry Co., Ltd.) 40 parts, xylene resin (Nikanol HP-100, Nippon Gas Chemical Co., Ltd.) 25 parts, polyisocyanate-based crosslinking agent 2.5 parts, and an appropriate amount of organic solvent are added. The pressure-sensitive adhesive layer coating solution obtained by sufficiently stirring until uniform becomes a pressure-sensitive adhesive layer having a thickness of 25 after drying on an easy-adhesive surface of a 25 μm polyester film that has been subjected to an easy adhesion treatment and a back surface release treatment in advance. The flame-retardant pressure-sensitive adhesive tape of the present invention was obtained by applying and drying to a thickness of ˜35 μm.

Example 3
30 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.) 50 parts, Styrene (YS Resin SX-100, Yasuhara Chemical Co., Ltd.) 30 parts, Polyisocyanate cross-linking agent 2.5 parts, and an appropriate amount of an organic solvent are added uniformly. The pressure-sensitive adhesive layer coating liquid obtained by sufficiently stirring until the thickness of the pressure-sensitive adhesive layer after drying on the easy-adhesive surface of the polyester film 25 μm that has been subjected to the easy-adhesion treatment and the back surface release treatment in advance is 25 to 35 μm. The flame-retardant pressure-sensitive adhesive tape of the present invention was obtained by coating and drying.

Example 4
30 parts of aromatic condensed phosphate ester flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.), aromatic condensed phosphate ester based on 100 parts of the solid content of the acrylic pressure-sensitive adhesive prepared above 30 parts of flame retardant (trade name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.) and 50 parts of aluminum hydroxide (trade name: Heidilite H-42M, Showa Denko Co., Ltd.) were added and mixed and kneaded (HM-3D). -5 Special Kika Kogyo Kogyo Co., Ltd.) kneaded and fully dispersed in the pressure-sensitive adhesive composition, 20 parts of xylene resin (Nikanol HP-100 made by Nippon Gas Chemical Co., Ltd.) and 2. polyisocyanate crosslinking agent. Adhesive layer of 25 μm polyester film that has been subjected to an easy adhesion treatment and a back surface release treatment in advance for 5 parts and a pressure sensitive adhesive layer coating solution obtained by sufficiently stirring until adding an appropriate amount of an organic solvent. Adhesive after drying The thickness of the layer is applied and dried such μm become 25 to 35, 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, And a hard-adhesive layer coating solution obtained by adding an appropriate amount of an organic solvent and stirring sufficiently until uniform, on the easy-adhesion surface of a polyester film 25 μm that has been subjected to an easy-adhesion treatment and a back-side 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, 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
30 parts aromatic condensed phosphate ester flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.) for 100 parts solid content of the acrylic pressure-sensitive adhesive prepared above. (Product name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.) 35 parts, 2.5 parts of a polyisocyanate-based crosslinking agent, and an appropriate amount of an organic solvent were added, and the resulting mixture was sufficiently stirred until uniform. It is difficult to apply and dry the adhesive layer coating solution on the easy-adhesive surface of the polyester film 25 μm that has been subjected to easy-adhesion treatment and backside release treatment so that the thickness of the pressure-sensitive adhesive layer after drying is 25 to 35 μm A flammable adhesive tape was obtained.

Comparative Example 6
30 parts of aromatic condensed phosphate ester flame retardant (trade name: PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.), aromatic condensed phosphate ester based on 100 parts of the solid content of the acrylic adhesive prepared above -Based flame retardant (trade name: CR-741, manufactured by Daihachi Chemical Industry Co., Ltd.) 30 parts, aluminum hydroxide (trade name: Heidilite H-42M, Showa Denko Co., Ltd.) 40 parts were added, and a mixing and kneading machine (HM- 3D-5 (made by Koki Kogyo Kogyo Co., Ltd.) and sufficiently dispersed until 2.5 parts of polyisocyanate crosslinking agent and an appropriate amount of organic solvent are added to the pressure-sensitive adhesive composition. The thickness of the pressure-sensitive adhesive layer after drying is 25 to 35 μm on the easy-adhesive surface of the polyester film 25 μm that has been subjected to the easy adhesion treatment and the back surface release treatment in advance. Apply / dry, flame retardant adhesive tape It 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 the flame retardancy, pressure-sensitive adhesive properties, and electrical properties 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 (7)

  A flame retardant adhesive in which 20 to 300 parts by mass of a phosphate ester flame retardant and 5 to 50 parts by mass of an aromatic-containing tackifier resin are added to 100 parts by mass of an adhesive base polymer on at least one side of a substrate. A flame-retardant pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer made of a composition.   The flame retardant pressure-sensitive adhesive tape according to claim 1, wherein the phosphate ester flame retardant is an aromatic phosphate ester flame retardant.   The aromatic-containing tackifying resin is at least one selected from a styrene-based resin, a xylene-based resin, an aromatic-containing terpene resin, and an aromatic-containing petroleum resin. The flame-retardant adhesive tape described.   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 4, wherein the flame-retardant pressure-sensitive adhesive tape passes the UL510 [electrical insulation tape standard] combustion test.   The flame-retardant adhesive tape according to any one of claims 1 to 5, 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 used for electrical insulation.