KR20050058220A - Flame retardant seal - Google Patents

Abstract

[PROBLEMS] To provide a flame retardant seal material which has excellent sealability and flame retardancy, and is very suitable for use in extremely harsh environments such as high temperature atmosphere or for high heat generating electronic or precision equipment.

RESOLUTION The flame-retardant seal material 10 is equipped with the elastic sheet 12 obtained by shape | molding the mixture which mixed the main raw material which consists of a polyol and an isocyanate, the sub raw material containing the foam stabilizer, and the metal hydroxide 16, and the foaming gas. 25-50 parts by weight of the metal hydroxide 16 is mixed with respect to 100 parts by weight of the electric polyol, and a substance capable of reacting with the isocyanate is used as a solvent for dilution of the sub-material. In addition, the flame retardancy specified in UL94 with respect to the seal member satisfies the HBF standard, and the 25% compression load is 0.03 MPa or less.

Description

Flame Retardant Seal

The present invention relates to a flame retardant seal material. More specifically, the present invention relates to a flame retardant seal material having excellent sealability and flame retardancy, and very suitable for use in a very harsh environment such as a high temperature atmosphere or for use in high heat generating electronic or precision equipment.

In electronic devices such as mobile phones, televisions, and displays of computers, input / output units such as liquid crystal display units, microphone units, and speaker units are disposed. This input-output part is provided in the site | part opened to the exterior of an electrical equipment case. For this reason, for example, in the case of a liquid crystal display, a sealing material is provided between the notes of the liquid crystal display and the case to prevent invasion of garbage, light leakage of the liquid crystal display backlight, and rattling shaking of the case. In recent years, in accordance with the request of high functionalization and light weight of various electric devices including mobile phones, such a seal material is required to be small and thin. As a raw material of such a sealing material, a polyurethane foam having excellent flexibility and low hardness at the same time can be suitably used because a thin film can sufficiently fulfill its role as a sealing material. In addition, since the polyurethane foam has little material deterioration (so-called wear) or gas generation, the polyurethane foam is suitable for use as a seal member provided in an electrical equipment case.

As mentioned above, the sealing material which consists of polyurethane foams has favorable characteristics as a sealing material. However, since the electric seal member is made of an organic material and has a high specific surface area and is formed on a thin sheet, when the electric sealer is assembled into an electrical device and an electronic device case, the high temperature is generated by the heat generated when the device is operated. There is a possibility. For this reason, high flame retardancy is also requested | required of a sealing material. On the other hand, generally, as a raw material of a sealing material, one type of flame retardants, such as (a) an organic bromine compound, a halogen type flame retardant which is an organic chlorine compound, (b) an organophosphorus compound, (c) antimony trioxide or (d) a metal hydroxide, or The technique which contains two or more types and improves flame retardance was employ | adopted widely.

However, when using the electric flame retardants (a) to (d), the following problems are pointed out.

(a) Since halogen-based compounds generate halides with a large environmental load during combustion, use as a flame retardant is not preferable.

When using the (b) organophosphorus compound as a flame retardant, it may be considered that the problem of deterioration in strength of the polyurethane foam and the adverse effect of inhibiting the production reaction of the polyurethane foam can be considered.

(c) Antimony trioxide is not suitable for use because it has been confirmed to impart the environmental load described above.

(d) When metal hydroxides, such as aluminum hydroxide and magnesium hydroxide, are used as a flame retardant, the above-mentioned environmental load does not have many problems. However, on the other hand, in order to satisfy the flame retardancy standard specified in UL94 (packing material and soundproofing material of weak pharmaceutical relationship), it is necessary to mix a large amount of metal hydroxide in the raw material of a polyurethane foam. In this case, there is a high possibility that the beneficial properties as the sealing material, for example, the low hardness, which the polyurethane foam should originally express, will be impaired.

In addition, UL94 is a standard for safety of electrical equipment established and approved by the United States Underwriters Laboratories Inc. (UNDERWRITERS® LABORATORIES® INC.). The flame retardancy specified in UL94 is a wire mesh of Bunsen burner or Tirrill burner 44 in the experimental apparatus 40 as shown in Figs. 5 (a) and (b). It is evaluated by measuring the burning distance and the burning time of the test piece 41 in accordance with the test piece 41 mounted on 42. In this UL94, in the case of the HBF standard for evaluating the flame retardancy of the test piece 41 in the horizontal burning test (Horizontal Burning Foamed Material Test) shown in Figs. 5 (a) and (b), the rectangular test piece 41 of 150 mm x 50 mm When the fire is set to one end in the long direction, the combustion speed from the position where the fire is set to (i) 100 mm away from the long direction of the test piece 41 does not exceed 40 mm / min and (ii) the test piece 41 It is assessed by which flare after ignition or by which glow disappears before reaching the 125 mm mark is achieved. In addition, the 125 mm mark of the previous time is provided in the position 125 mm apart in the longitudinal direction of the test piece 41 from the position which matched the weave.

In order to overcome the electric problem and achieve the desired purpose, the flame-retardant seal member of the present invention is formed of a mixture of a main raw material consisting of polyols and isocyanates, a subsidiary material including a foaming agent, and a metal hydroxide (16), and a mixture of a foaming gas. The elastic sheet 12 which can be obtained is provided. Moreover, this flame retardant seal material is mixed with 25 to 50 parts by weight of the metal hydroxide (16) with respect to 100 parts by weight of the electric polyol so that a substance capable of reacting with the isocyanate is used as a solvent for dilution of the secondary raw material. The flame retardancy satisfies the HBF standard and is characterized by a 25% compression load of 0.03 MPa or less.

EMBODIMENT OF THE INVENTION Hereinafter, the suitable Example of the flame-retardant seal material of this invention is described, referring an accompanying drawing. The inventor of this application obtained the following knowledge as a result of earnestly researching about a flame-retardant seal material. That is, the polyurethane foam is extremely low in the content of unreacted monomers and low molecular oligomers which volatilize by heating to form a combustible gas component and thereby reduce flame retardancy. Therefore, a polyurethane foam is suitable as a raw material of a sealing material. In addition, by employing the mechanicafuros method, it is possible to avoid the use of an amine catalyst, which is a highly volatile low molecular substance, and to suppress volatilization of the foam stabilizer, which is indispensable for producing a foam. The flame retardant seal material thus obtained has sufficient flame retardancy and sealability while the amount of metal hydroxide mixed is reduced.

In the present invention, the flame retardancy and sealability, which are characteristic properties of the flame retardant seal member, are defined by the HBF standard and 25% compression load (hereinafter referred to as 25% CLD (Compression Load Deflection)) defined in UL94. . Therefore, the flame retardancy is evaluated by satisfying the HBF standard, and by checking whether the 25% CLD, which is an index indicating flexibility, is 0.03 MPa or less.

As shown in Fig. 1, the flame retardant seal member 10 is formed of an elastic sheet 12 made of a foam having various physical properties such as cushion properties, sealability, flexibility, and shape followability, and is laminated on one side of the elastic sheet 12 to provide structural characteristics of the flame retardant seal member 10. It consists of the base film 14 for improving strength. The electro-elastic sheet 12 is manufactured by a well-known mechanica-fluoros method. Specifically, the foam raw material M is prepared by mixing a main raw material consisting of a polyol and an isocyanate, a sub raw material including a metal hydroxide 16 as a foam stabilizer and a flame retardant, and a foaming gas to prepare a foam raw material M, and then the foam raw material M is molded on a sheet. Inside the elastic sheet 12, the metal hydroxide 16 is homogeneously dispersed (see Figure 1). The detail of the mechanica furros method is described, for example in Unexamined-Japanese-Patent No. 53-8735. In summary, the mechanica furros method is a method of obtaining a foam by introducing a gas into a liquid material and mechanically mixing it.

As the physical property value of the elastic sheet 12 thus obtained, in order to evaluate the sealability, (1) 25% CLD is required to be 0.03 MPa or less as an index of flexibility. 25% CLD represents the hardness of the elastic sheet 12 when the load required when applying 25% physical compression, that is, when 25% physical compression is applied. Moreover, as another physical property value of the elastic sheet 12, as an index | index for evaluating both sealing property and flame retardance, it is preferable that (2) density is 240-500 kg / m <^3> . As other physical-property value of the elastic sheet 12, it is preferable that (3) thickness is 0.3-3.0 mm.

Here, when 25% CLD exceeds 0.03 MPa, since the flexibility of the elastic sheet 12 will fall, sufficient sealing property will not be exhibited. If the density is less than 240 kg / m ³ , bubbles become sparse in the elastic sheet 12, so that the contact area with air increases and the HBF standard prescribed by UL94 is satisfied. On the contrary, when density exceeds 500 kg / m <^3> , since 25% CLD will also increase simultaneously, the sealing property of the elastic sheet 12 will fall. If the thickness is less than 0.3 mm, the sealing property of the elastic sheet 12 becomes difficult to be sufficiently exhibited, and the ignition property to the woven fabric becomes high, so that the HBF standard prescribed by UL94 becomes difficult to be satisfied. On the contrary, when the thickness exceeds 3.0 mm, it is too thick to be incorporated into a small product such as a mobile phone with limited installation space.

In addition, as physical property values other than the above required for the elastic sheet 12, it is necessary to satisfy the HBF standard specified in (4) UL94 as an index for evaluating flame retardancy. The flame retardance of the elastic sheet 12 was mixed with the foam raw material M by mixing a metal hydroxide 16 as a flame retardant in a predetermined ratio, and by mixing a dispersion of a foam stabilizer using a substance capable of reacting with an isocyanate such as a polyol as a solvent for dilution, It can increase.

As described above, in the production of the elastic sheet 12, as in the case of manufacturing a normal polyurethane foam, a subsidiary material including a main raw material consisting of polyols and isocyanates and a metal hydroxide 16 as a foam stabilizer and a flame retardant is used. In addition, at this time, if necessary, at least one kind of subsidiary material selected from a blowing agent, a crosslinking agent, a plasticizer and a catalyst can be used. Here, it is preferable that content of the polyol and isocyanate in elastic sheet 12 is set to about 20 to 45 weight% and about 25 to 35 weight%, respectively. The content of the foam stabilizer (including the diluent solvent) in the elastic sheet 12 is preferably set to 2 to 3% by weight, 8 to 15% by weight of the crosslinking agent, and 3 to 5% by weight of the catalyst. . In addition, in manufacture of this elastic sheet 12, the mixing amount of the gas for foaming, such as an inert gas used by the mechanica flow method, is about 50-200 volume% with respect to the total volume 100 of all raw materials except the said gas for foaming. Is suitable.

As the metal hydroxide 16, aluminum hydroxide or magnesium hydroxide in which the hydroxyl group (-OH) in the molecule dissociates by heating to generate water can be used. The mixed amount of the metal hydroxide 16 is preferably set to 25 to 50 parts by weight, more preferably 30 to 35 parts by weight with respect to 100 parts by weight of the polyol. If the amount is less than 25 parts by weight, the desired flame retardancy is not exhibited. On the contrary, if the amount is more than 50 parts by weight, the flame retardant seal material 10 becomes hard or brittleness develops and the sealability is lowered.

The average particle diameter of the metal hydroxide 16 is preferably set in the range of 10 to 100 µm, more preferably 20 to 60 µm. When the average particle diameter of the metal hydroxide 16 is less than 10 μm, the viscosity of the foam raw material M increases or the water content of the foam raw material M increases, resulting in foaming reaction of water and isocyanate. Manufacturing becomes difficult. On the contrary, when the average particle diameter of the metal hydroxide 16 exceeds 100 μm, the metal hydroxide 16 easily precipitates when the metal hydroxide 16 is mixed with the foam raw material M, so that it is difficult to properly disperse the metal hydroxide 16 inside the elastic sheet 12. Become. In the flame-retardant seal material 10 produced using the foam material M in which the metal hydroxide 16 has settled, a problem arises in which the flame retardancy differs depending on the site. Moreover, although manufacture of the flame-retardant seal material 10 can be terminated before sedimentation of the electrometallic hydroxide 16, in this case, since manufacture time is limited, there exists a possibility that suitable manufacture may be inhibited.

As a foam stabilizer, a well-known silicone foam stabilizer is used suitably. This foam stabilizer is indispensable for the production of polyurethane foams by the mechanica-fluoros method. However, since the foam stabilizer is a low molecular material, it is easy to burn and may be one factor that lowers the flame retardancy of the elastic sheet 12. In addition, since the foam stabilizer of silicone type | system | group is very high as it is, it is necessary to dilute and use it with a solvent for dilution. As a solvent for diluting the foam stabilizer, a substance capable of reacting with an isocyanate such as polyol is used.

When the elastic sheet 12 is prepared using a foam stabilizer dispersed in a polyol as a solvent for dilution, the polyol, which is a dilution medium, reacts with an isocyanate, which is the main raw material of the elastic sheet 12, to form polyurethane molecules, and the foaming agent is taken into the polyurethane molecules. . As a result, volatilization of a foam stabilizer is prevented in the obtained elastic sheet 12, and a flame retardance fall factor is reduced. It is preferable that the quantity of the solvent at the time of diluting a foam stabilizer is set so that content of a foam stabilizer may be in the range of 30 to 70 weight%. When content of an electrostatic foaming agent is less than 30 weight%, the foaming function at the time of manufacturing elastic sheet 12 falls. On the contrary, when content of a foam stabilizer exceeds 70 weight%, since the viscosity of a foam stabilizer dispersion rises, it will become difficult to handle at the time of manufacture.

In general, as a solvent for diluting the silicon foam stabilizer, a liquid low boiling point substance having low viscosity at room temperature such as alkyl benzene is suitably used. However, such low-boiling materials have a high risk of impairing the flame retardancy of the product because they are easily volatilized. Such low boiling point substances include not only solvents for dilution but also various kinds of substances such as monomers and antioxidants used in the synthesis of polyols as main raw materials. Therefore, as one condition for the flame retardancy specified in UL94 to satisfy the HBF standard, the content of a substance (hereinafter referred to as a substance to be dissolved) that can be dissolved in acetone in the elastic sheet 12 is defined. In this invention, it is preferable that content of the to-be-dissolved substance in the elastic sheet 12 is 5.0 weight% or less. When the content of the electrically soluble substance exceeds 5.0% by weight, even if the mixed amount of the metal hydroxide 16 and all the conditions relating to the foam stabilizer are satisfied, the inventors found that the flame retardancy specified in UL94 could not satisfy the HBF standard. It is confirmed by.

Content of this to-be-dissolved substance is calculated | required by measuring the extraction rate, ie, acetone extraction rate, when extracting elastic sheet 12 with acetone, for example. An example of the specific measuring method of acetone extraction rate is given as an experiment example mentioned later. In addition, when a low boiling point material such as alkyl benzene is used as the solvent for diluting the foam stabilizer, the low boiling point material is present in the free form outside the molecular structure of the polyurethane inside the elastic sheet 12. There is also a possibility that the problem of the transferability of the solvent to shift to a member such as a case which comes into contact with. Therefore, by using the substance which can react with isocyanate, such as a polyol, as a solvent for diluting a foam stabilizer, the effect which greatly suppresses the problem of the said transferability can also be anticipated.

As described above, the base film 14 is integrally laminated with respect to the elastic sheet 12 so as to improve the structural strength of the flame retardant seal member 10 to improve the handleability of the product. This base film 14 also plays a role as a transport medium of the foam raw material M in the production apparatus 30 as described in the production method described later. Accordingly, the substrate film 14 needs to have physical strength capable of countering the tension applied by the roll mechanism 32 and resistance to heat that can be applied to the tunnel furnace 38 to cure the foam raw material M. As the material of the base film 14, a resin such as polyethylene terephthalate (PET), which is more difficult to heat shrink than a general-purpose resin such as polyethylene (PE) or polypropylene (PP), is preferable. Moreover, although the thickness of the base film 14 changes with materials, Preferably it is set to about 12-500 micrometers, More preferably, it is set to about 25-125 micrometers. Even if the base film 14 of this thickness is laminated | stacked on the elastic sheet 12, it does not adversely affect the sealing property of the flame-retardant sealing material 10. FIG. In addition, when the flame-retardant seal material 10 is molded using a molding form, for example, the base film 14 becomes unnecessary, so that the flame-retardant seal material 10 made of only the elastic sheet 12 as shown in Fig. 2 is obtained.

(An example of a manufacturing method)

An example of the suitable manufacturing apparatus of the flame-retardant seal material 10 of this embodiment, and the manufacturing method of the flame-retardant seal material 10 using the manufacturing apparatus are demonstrated below. The manufacturing method of the flame-retardant seal material 10 is comprised from raw material preparation process S1, raw material supply and shaping | molding process S2, heating process S3, and final process S4, as shown in FIG. This flame-retardant seal material 10 is manufactured by the manufacturing apparatus 30 shown in FIG.

This manufacturing apparatus 30 is equipped with the mixing part 31 which mixes a main raw material, various sub raw materials, and the gas for foaming in order to obtain the foam raw material M of the polyurethane foam for implementing the mechanica-fluoros method. Moreover, this manufacturing apparatus 30 is equipped with the roll mechanism 32 which consists of the supply roll 32a and the product collection | recovery roll 32b which transfer the base film 14 as a conveying medium of foam raw material M using the drive source which is not shown in figure. The foam raw material M is supplied from the discharge nozzle 34 to the base film film 14. On the downstream side of the discharge nozzle 34, a product thickness control means 36 such as a knife coater for molding the foam raw material M into a sheet of a predetermined thickness is provided, and a tunnel heating furnace 38 is provided downstream of the product thickness control means 36. In addition, although the foam raw material M is made to react and harden here on a planar surface, you may make it react and harden | cure on the inside of a required shaping | molding die or a release paper.

The mixing section 31 is a container 31a for a polyol containing a polyol as a main raw material, a container 31b for an isocyanate containing an isocyanate as a main raw material, a container 31c for a foaming agent containing a foaming agent as a subsidiary material, and a metal hydroxide containing a metal hydroxide 16 as a subsidiary material. The container 31d is provided. In addition, it is also possible to provide a container in which auxiliary materials other than the foam stabilizer and the metal hydroxide 16 are contained as needed. Moreover, the mixing part 31 is equipped with the container 31e and the mixer 31f in which the gas for blisters were filled. The raw material in each container 31a-31e is supplied under control by the mixer 31f, and is mixed in the mixer 31f.

The roll mechanism 32 supplies the base film 14 to a manufacturing line, applying the tension to the base film 14, and collects the flame-retardant seal material 10 obtained. On the production line, a discharge nozzle 34, a product thickness control means 36, and a tunnel heating furnace 38 are provided between the supply roll 32a and the product recovery roll 32b. The base film 14 is wound around the supply roll 32a, and the supply roll 32a sends out the base film 14 under control to a manufacturing line. The discharge nozzle 34 has one end connected to the mixing section 31, and discharges the foam raw material M mixed in the mixing section 31 to the surface of the base film 14 transferred on the production line under control. In the raw material preparation step S1 performed in the mixing section 31, after preparing the main raw material, the sub raw material, and the gas for the crude fabric by a conventionally known method, the foam raw material M is manufactured by mixing them using the mixer 31f.

In the raw material supply and molding step S2, the foam raw material M is discharged onto the base film 14 from the discharge nozzle 34, and then the foam raw material M is molded through the product thickness control means 36 in a state of being placed on the base film 14. The product thickness control means 36 forms the foam raw material M discharged on the substrate film 14 into a sheet having a predetermined thickness (0.3 to 3.0 mm).

In heating process S3, the laminated body of the foam raw material M and the base film 14 shape | molded in the sheet form is heated in the tunnel type furnace 38. The tunnel heating furnace 38 heats the foam raw material M molded to a predetermined thickness under control, thereby reacting and curing the foam raw material M to obtain a flame retardant seal material 10.

In final process S4, after obtaining the flame-retardant seal material 10 shape | molded in elongate shape through each process S1-S3, the final inspection of the flame-retardant seal material 10 is performed. At this time, the work which emulates the flame-retardant seal material 10 to the shape of a final product can also be performed as needed. The flame-retardant seal material 10 after the final inspection is wound around the product recovery roll 32b to be in a state where it can be shipped. In this manufacturing method, since the flame-retardant seal material 10 can be manufactured with the elongate article of 5 m or more, for example, manufacturing cost can be reduced significantly.

Experimental Example

Hereinafter, using the manufacturing apparatus 30 shown in FIG. 4, after manufacturing a flame-retardant seal material on the conditions described in Table 1 (Examples 1-8) and Table 2 (Comparative Examples 1-8), the various physical properties of the obtained flame-retardant seal material The experimental example evaluated about is shown.

To 100 parts by weight of polyether polyol (average molecular weight 3000, hydroxyl value 43.0), 0.1 part by weight of a metal catalyst (stannous octoate), 3 parts by weight of a silicon foam stabilizer (including a dilution solvent) and a metal hydroxide 16 (about a mixed amount Table 1 and Table 2) were mixed to obtain a mixture. In this mixture, nitrogen gas (gas for gas preparation) and polyisocyanate (crude MDI, NCO content: 31%) set so that the isocyanate index is 0.9 to 1.1 are mixed and sheared at a flow rate of 0.1 NL / min to foam raw material M Got. This foam raw material M was discharged onto the substrate film 14 (manufactured by PET) having a predetermined thickness through the discharge nozzle 34. At this time, the base film 14 is continuously supplied from the supply roll 32a in a state where tension is applied on the roll mechanism 32. In addition, the electric foam raw material M is supplied from the discharge nozzle 34 so that the density of the elastic sheet 12 after manufacture may be the numerical value of Table 1 and Table 2, and the thickness of the elastic sheet 12 after manufacture is the numerical value of Table 1 and Table 2 Molded in the product thickness control means 36 as possible. Furthermore, the foam raw material M laminated | stacked on the base film 14 was heated and reacted and hardened | cured for 1 to 3 minutes at 150 degreeC-200 degreeC in tunnel heating furnace 38. As a result, the flame-retardant seal material in which the elastic sheet 12 was laminated | stacked on the upper surface of the base film film 14 was obtained. The obtained flame-retardant seal material was recovered by the product collection roll 32b.

The used metal hydroxide 16 and the foam stabilizer are as follows.

Metal hydroxide: Aluminum hydroxide (brand name Heidi light H-21 (average particle size 25μm) made from fire extinguishing major)

· Foaming agent ：

(A) OSi Specialties brand name # L-5617 (a product containing polydimethyl siloxane and polyoxy alkylene in a polyol as a dilution solvent in a proportion of 50% by weight)

(B) OSi's Osi Specialties brand name L-5614 (a product containing polydimethyl siloxane and polyoxy alkylene in a proportion of 50% by weight in alkyl benzene as a solvent for dilution)

The base film 14 was peeled off from the flame-retardant seal material of Examples 1-8 and Comparative Examples 1-8 manufactured according to Table 1 and Table 2, and only the elastic sheet 12 was obtained. From the obtained elastic sheet 12, for measuring the content of the specimen 41 having a predetermined thickness × 150mm × 50mm for flame retardancy evaluation, the circular specimen having a predetermined thickness × φ50mm for measuring 25% CLD, and the substance to be dissolved 1 g of test pieces were obtained, respectively. About these test pieces, the acetone extraction rate (%) which shows 25% CLD (MPa) and content of a substance to be dissolved was measured, respectively. In addition, using the experimental apparatus 40 shown in Fig. 5, the flame resistance specified in UL94 was evaluated. In this flame retardancy evaluation, when the HBF standard was satisfied, each of them was described in the table as a ○ table and, when not satisfied, a × table. Moreover, from these results, the suitability as the flame-retardant seal material of this invention was comprehensively evaluated. In the comprehensive evaluation of the said electricity suitability, the case where it was suitable was described in the comprehensive evaluation column in a table | surface in the table | surface and the case where it is unsuitable by x mark, respectively. In addition, whether or not the elastic sheet 12 contained alkyl benzene was also investigated and described in the table. The measuring method and measurement conditions are as follows.

(Measurement method and condition)

Density: It measured based on JIS K 6401. That is, 50 mm x 50 mm square test piece was extract | collected, and the weight and volume of the test piece were measured using the dial thickness meter and the electronic balance. And calculation formula: density (kg / m <^3> ) = the density of the elastic sheet 12 was calculated according to the weight (kg) of the test piece / volume (m <^3> ) of a test piece.

25% CLD: Using a compression tester, the test piece was compressed until it became 25% of the original thickness at a compression speed of 1 mm / min, and the load at that time was measured. And calculation formula: 25% CLD (MPa) = 25% Compression 25% CLD was computed according to the load (N) / area of the test piece (cm <^2> ).

Flame retardancy: Using the experimental apparatus 40 shown in Figs. 5 (a) and (b), the flame retardance of the test piece 41 was evaluated based on the HBF standard specified in UL94.

The amount of the substance dissolved in acetone (acetone extraction rate): The test piece of the elastic sheet 12 (here, 1 g) is set in an extractor, and the acetone is heated and refluxed for 3 hours to extract the substance dissolved in acetone. After the extraction, the extract was dried to measure dry weight. And calculation formula: Acetone extraction rate (%) = Acetone extraction rate was computed according to the test piece weight (g) * 100 before setting to the dry weight (g) of a extract / quick-dry extractor.

-Content of alkyl benzene: The said extract was subjected to spectrum analysis by gas chromatography mass spectrometer (GC-MS; brand name QP-5000 by Shimadzu Corporation), and evaluated.

(result)

The results are shown in the table below. From Table 1 and Table 2, it was confirmed that the flame-retardant sealing material which has flame retardance and sealability can be obtained by making each physical property value of the elastic sheet 12 into the range set by this invention.

The flame retardant seal material of the present invention has excellent sealability and flame retardancy, and is very suitable for use in extremely harsh environments such as high temperature atmosphere or for use in highly heat-generating electronic or precision instruments.

1 is a perspective view showing a part of the flame retardant seal material of a preferred embodiment of the present invention.

2 is a perspective view showing a flame retardant seal member having no base film.

3 is a flowchart illustrating a method of manufacturing the flame retardant seal member of the embodiment.

It is an example of the manufacturing apparatus which manufactures the flame-retardant seal material of an Example.

In FIG. 5, (a) is a perspective view showing the entirety of an experimental apparatus for carrying out the flame retardancy test specified in UL94, and (b) is an enlarged view showing the vicinity of a test piece of the same experimental apparatus.

[Description of the code]

10 Flame retardant seal material

12 elastic sheet

16 metal hydroxide

Claims (5)

A flame retardant seal material comprising an elastic sheet (12) obtained by molding a mixture of a main raw material consisting of a polyol and an isocyanate, a sub raw material including a foam stabilizer and a metal hydroxide (16), and a gas for blistering, 25-50 parts by weight of the metal hydroxide 16 is mixed with respect to 100 parts by weight of the electric polyol, and a substance capable of reacting with the isocyanate is used as a solvent for dilution of the secondary raw material, A flame retardant seal member characterized by the fact that the flame retardancy specified in UL94 with respect to the seal member satisfies the HBF standard and the 25% compressive load is 0.03 MPa or less. The flame-retardant seal member according to claim 1, wherein the electro-elastic sheet 12 contains 5.0 wt% or less of a substance that can be dissolved in acetone. The flame-retardant seal material of Claim 1 in which the average particle diameter of the electrometal hydroxide 16 is set in the range of 10-100 micrometers. The thickness of the electroelastic sheet 12 is 0.3-3. The flame-retardant seal material of Claim 1 set in the range of 0 mm. The flame-retardant seal material as described in any one of Claims 1-4 with which the density of the electroelastic sheet 12 is set in the range of 240-500 kg / m <^3> .