TWI300086B - Low density composition based on epdm rubber - Google Patents

Description

1300086 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention is a component of a flame-retardant layer, particularly a low-density rubber composition. [Prior Art] - Generally speaking, a propellant system for a solid rocket motor It consists of a variety of high-energy oxidizers; after ignition, it generates a large amount of gas and emits extremely high heat. This heat accumulates in the limited space inside the engine casing, and its temperature can be as high as ～C to 37〇 ( TC, will endanger the safety of the engine casing. Therefore, for all types of missiles with solid fuel as propellant, 'there must be a flame-retardant device in the engine to maintain safety. The composition of the traditional brewing layer, Mostly used as a filler with flame-resistant materials such as stone, strontium, hydroxide (a_)3), bismuth oxide (sb2〇3), dioxo (si〇2) and organic flame resistant materials, etc. In the formulation, the film is further processed. During the construction, the flame-retardant layer is processed to adhere to the inner wall of the rocket engine casing, which can produce a flame-retardant effect when the engine is ignited and ignited. For example, U.S. Patent No. 3 No. 347047 (1967), which is made of asbestos as a filler, added to the rubber formulation to make a flame-retardant film, which can be processed by the die-casting method; wherein 'the asbestos added to the rubber formula is 3 to ·Cai (Shuai (four) This is rcsin by weight; every 100 parts by weight of rubber added weight injury). = According to the scales method (four) red into the United States Ae_ company produced (also 8 gm / cm) 'the system In order to add asbestos to the flame retardant layer of nitrile rubber 6 1300086 Material 'Because of the flame retardant effect, it is widely used in many types and large missiles in various countries'. For example: Patriot missiles and angels of Israel (el) Fine aeroelastic 'Because it contains a large amount of asbestos fibers, it is inevitable that in the manufacturing process of the flame-retardant layer or after the launch of the rocket, the stone is inevitable, and the new one is in the silk scarf' (4). Directly create a large health hazard and have a permanent adverse effect on the environment. In addition, as in US Patent No. 45〇1841 (touch year) and No. 4 prefecture 10 (1989), it adopts aromatic Polyamide fiber (p 〇 lyaramide fiber, trade name · Kevlar) and inorganic fillers used in place of asbestos fibers in rubber formulations, according to the production of adhesives > [. fine, the density of such Lai material is relatively large (about 1.4 Gm/cm to 15gm/cm3), thus relatively reducing the load capacity of the rocket engine. • Again, as shown in US Patent No. 5,821,284 (1998), it is proposed to contain square incense scales. Base ternary (she added e net • te$dy bribe 'EPDM) rubber formula towel, adding ammonium sulfate ((NH4) 2S 〇 4) and antimony trioxide (Sb2Q3) 'mesh co-fusion effect (ah. Ten streams. Μ), and can effectively raise the flame retardant layer (4), and the density of the glue can be reduced to gm/cm. However, in the process of burning the flame retardant layer, the toxic gas is generated, which is easy to cause harm to the environment. "In addition, as shown in U.S. Patent No. 4,874,431 (1989), it is proposed to use a chlorinated compound (for example: Dechlorain Plas 515) as a charcoal-resistant filler, or as a US patent milk (four) (10) 6 years) As shown, 7 1300086 is made of chl〇r〇sulfonated polyethylene (commonly known as Hypalon) as the base rubber. The rubber flame retardant layer made of these materials decomposes due to high temperature when the rocket is burned, and it is easy to generate cerium chloride (HC1) gas, which is a corrosive gas, and makes the fire W emit gas smoke concentration. obviously increase. In U.S. Patent No. 5,023,006 (1991), 2-chlorobutadiene and 1,3-elastomer are added to EPDM rubber to produce a flame retardant layer. And using 4a a, a_bistertyl peroxide (a, a'_biStertbUtylperoxide) and diisopr〇pylbezene as a curing agent, wherein the aromatic polyamine fiber used is Staples with a length of 0·25 mm. The physical properties and density data of the rubber materials are not discussed. In U.S. Patent No. 5,498,649 (1996), a flame retardant layer is formed by using a polyamine polymer and a maleic anhydride EpDM rubber, which indicates that the density of the rubber material can be lowered. No data on the resistance to burned surnames has been proposed, and the age-resistance of the made layered materials cannot be increased. The flame-retardant layer material proposed here is a thermoplastic adhesive (also _^ • )/, a thermosetting type different from the flame-retardant layer. In US Patent No. 6556420 (10) 3 years) and No. 6_52 (2〇〇3 years ^', the EPDM flame retardant layers described in the article are all based on peroxides (卩) (4) as a coating agent, and both rely on And in the flame retardant layer of the formulation of the fiber, ..., and according to the scale _ difficult 峨 layer, the density is greater than the wall (five) 3. = This can be seen, in the known flame retardant layer literature, the density of the glue is more than gm When the rocket is launched, the button effectively reduces the weight of the engine by 8 1300086 (the engine component; I; the weight of the thrust portion). [Invention] In view of the above problems, the main object of the present invention is to provide a low Density Rubber 2 1 is suitable for use as a stripe of Saki: Layers, which is based on the problems revealed by the prior art. According to the fineness of the handle, the rubber is suitable for the ribs as a flame retardant layer, and the Tianqi is used as a fire. When the engine is _, the layer, the lining rocket engine 岐 high heat and high-speed gas particles rely on a relatively gentle area, which can fully reduce the weight of the engine component without the thrust part. Easy to carcinogenic asbestos fiber. The above object is a low-density rubber composition disclosed in the present invention, which is suitable for use as a flame retardant layer of a rocket engine, and the main components are EPDM rubber and aromatic poly-fiber. Further, an inorganic filler such as Al (OH) 3 and/or SiO 2 is used as an ablative filler. Among them, an aromatic polyamide fiber having an organic component is used. It can be used to replace the asbestos fibers in the traditional fire-retardant layer. Because it can be completely carbonized after ablation, it can ban the pollution caused by the use of asbestos. In addition, it also contains liquid EPDM rubber. Adjusting the softness of the raw rubber, so that the finished product can be quite soft. Therefore, it can be applied to the 1300086 method such as handlayup or inflatable technique. The inner wall of the rocket engine casing, in order to avoid the inclusion of a large amount of aromatic polyamide fiber in the flame retardant layer (3 〇, to 12〇)

Phr) ‘There is a high hardness of the finished product, which necessitates the use of sophisticated and expensive processing equipment. Furthermore, after the raw rubber glue is heated and matured, the flame retardant layer has the characteristics of low bulk, low heat conductivity, moderate hardness and appropriate ablation resistance, so when it is used as The flame retardant layer of the rocket engine inner towel section (here, when the propellant is burned, the area is more gently tempered by the high-heat high-speed gas particles), effectively reducing the weight of the engine. Moreover, the low-density rubber flame-retardant layer composition, by appropriate processing method, will be placed on the inner wall of the engine steel shell and heated to be matured, and can be converted into a hard carbon layer (hardchar) by burning, which is effective The ground prevents the high temperature of 2400 C to 3700 C generated when the propellant is burned, so as to protect the outer casing of the rocket engine from being dissolved, thus ensuring flight safety. The features and implementations of the present invention are described in detail as a preferred embodiment. [Embodiment] Hereinafter, specific embodiments will be described to explain the contents of the present invention in detail. Herein, a thermosetting rubber material is used as a flame-retardant rubber material, which is replaced by a stone of a conventional flame-retardant face towel, and a polyaramide fiber. Add A1 (〇H) 3 and other , 2 as an ablative filler in the flame retardant layer. The formula uses methyl ethyl ternary rubber (EPDM rubber as a kind of glue for various types of processing. The reason for using EPDM rubber in this 10 1300086 is that it has low density, excellent aging resistance and softness at low temperature. Good quality and other characteristics. At the same time, the addition of liquid jade rubber in the formula can adjust the softness of the raw rubber material, making it suitable for the processing conditions of the inner wall of the rocket engine casing.

The flame retardant layer produced in accordance with the present invention has many advantages, such as low density (according to the test method for the density of the glue material (ASTM D 792) as defined by the American Society for Testing Materials (ASTM). Determination, the density can be lower than the hardness shot (measured hardness value (10) (10)

Approximately 7〇±7), low heat transfer coefficient (determined according to ASTMC 581 test method, its heat transfer coefficient is about 〇245 Kcal/mh t:) and excellent resistance to burnt money (determined according to ASTM E 285 test method) , get the burnt rate of about $ 〇. i22 face / sec) and other chicks. The red flame-retardant layer of the invention has good aging resistance at the same time and is excellent at low temperature (_50. 〇 softness is good, etc.), and the defect made according to the invention is hindered by the secret. The gas is mildly toxic, and it has an environmentally friendly concept. 'S full-face--the rocket's reliance on the material requirements of the layer. In addition, because of its low density, it is especially suitable for use as a propellant. The high-speed fuel-burning lining relies on the gradual zone __ layer material, which effectively reduces the engine's weight, and thus increases the rocket's speed and range. According to the hairline fine EpDM _ as the silk glue, and the furnace as the 彳, enable It is suitable for the transformation of _ layer to set up the boots to be the seal of the vessel. Moreover, the program used can be the colloidal sulfur wall for the formulation of the middle-grade rubber duty to the ice.

1300086 is from 0.5 phr to 2.5 phr. The rubber ripening accelerators used herein are: N-tert-butyl-2-benzothiazole sulfenamide and 4,4-sulfurized bismuth. One of the 4,4'-dithio dimorpholine, or a mixture thereof. Wherein N-tert-butyl-2-benzothiazole sulfenamide can be used in an amount of DM.〇1 {)111< to 3 phr of the weight of the EPDM rubber, wherein the preferred amount can be from 〇.5 phr to 2 phr' and 4,4 The amount of '-dithio dimorpholine may range from 0.01 phr to 3 phr by weight of the EPDM rubber, with a preferred amount being from 5 phr to 2 phr. Further, an aromatic polyamine fiber (p〇lyaramide fiber) is also included in the formulation, and the melamine fiber is preferably paper-recorded, and has a length to diameter ratio of about 500. In this case, the length of the paper-like aromatic polyamide fiber may be from 咖5 to 4 mm, and the preferred length may be from i mm to 3 coffee. Moreover, it can be used in the formula of 5 phr to 2G _ of the basic rubber, and the ration can be preferably phr to 15 phr. Among them, the applicable physical properties of Guanhe Yifang Poly-δ & amine fiber are shown in Table 1. 12 1300086 Table 1 Properties of Aromatic Polyamide Fibers Physical Properties (Units) Required Tensile Strength (kg/cm2) 30,000 to 40,000 Tensile Moments (kg/cm2) 7.6x10s ~1χ1〇1ϋ Elongation (%) 3~ 5 Density (gm/cm3) 1.4 〜1·5 Fiber diameter (μιη) 10 ～14 Decomposition temperature (°c) 400 ～600 Thermal expansion coefficient (1/°G -2χ1 (Γ6 In addition, in the flame retardant layer formulation and adopted Liquid EpDM rubber, in order to adjust the softness of the flame retardant green film, thereby enhancing the adhesion of various solid fillers and aromatic polyamine fibers to the solid EPDM rubber, so that it can be mixed evenly. Liquid EPDM rubber and solid The basic chemical composition of the sad EPDM rubber is the same, but the molecular weight is different, because it can be completely compatible. The liquid EPDM rubber is used in the flame retardant layer formulation, and can be used as a seal in the flame retardant layer, with the greenness of the machine film. The effect, when the flame retardant layer is heated and matured, the liquid EPDM rubber and the solid EpDM rubber are simultaneously catalyzed by sulfur and a sulfur-containing accelerator, and the common ripening reaction (c〇_vulcanizati〇n). Thus, the liquid EPDM rubber Rubber for plasticizer After the aging of the fuel layer, the flame retardant layer does not cause plasticizer migration during the storage of the missile. The liquid EPDM rubber is present in the flame retardant layer of the raw rubber material, and has a tack. The effect can improve the self-mystery between the film layer and the layer of the flame-retardant layer. If combined with the additive 13 13300086 (tackifier), the effect of increasing the dryness can be improved. In this case, the synthetic coalescence resin is used as the increase (4). The amount of money is from EpDM to i〇phr, preferably from 4 phr to 8 phr. Further, in order to improve the ablation resistance of the flame-retardant layer, a1(〇h)3 and Si〇2 may be used here. As an ablative filler in the formulation of rubber, among them, A1(〇H)3 releases water molecules due to decomposition under high heat ablation, and the released water molecules can effectively cool the ablated flame retardant. The surface layer of the layer can prolong the ablation time of the flame retardant layer and further increase the ablation resistance. Further, the Si〇2 in the formulation can be a wet-processed cerium oxide powder; Before the ingredients, they must be treated with a coupling agent to increase the cerium oxide and EPDM rubber. Here, the coupling agent selected may be a mercapto-fiinctional silane having a terminal group of thiopurine (SH-), for example, the trade name Union Carbide A_ 189 (SHCH2CH2CH2Si(OCH3)3 A product that causes chemical bonding between the cerium oxide and the rubber molecules to enhance the physical properties of the flame retardant layer. Column 1 407.0 g (7 〇 phr) EPDM rubber was added to a 1 liter Banbury mixer for 20 seconds (sec); then, 174 gram (30 ph liquid EPDM rubber and 87·7 g (12.5 phr) of aromatic polyamide fiber, and then fully kneaded for 40 seconds, so that the liquid rubber adheres to the surface of the aromatic polyamide fiber, and it can fully bite with the solid EPDM rubber; then, add 7.0 After gram (1 phr) stearic acid, mix for 20 seconds; then add 35.1 g (5 pjxr) of two 14 !300086 cerium oxide and 70.2 g (10 phr) of cerium alumina, fully kneaded for 30 seconds; then add 7· 4 g (1 phr) of substituted diphenyl antioxidant and 35.1 g (7 phr) of synthetic polyterpene resin tackifier, mixed for 30 seconds; then, add 35.1 g (5 phr) of zinc oxide, mix for 20 seconds Then, after removing the rubber, 14.1 g (2 phr) of sulfur and 7·0 g (1 phr) of 4,4'-disulfide vulcanization accelerator were added to the two-roller, and the mixture was thoroughly mixed. In this way, a low-density rubber composition according to the present invention suitable for use in a rocket flame retardant layer can be obtained.

Embodiment 2 to Embodiment 5 Repeat the operation steps of the embodiment 1 'the mixture thereof _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Low density rubber composition.

Table 2: Real Blend 5 Mixing Operation Procedure Adding material) epdm^—'- 歹香族聚耐耐剂 Mixing time (seconds) 20

Inorganic filler

15 1300086 Table 3 Formulations of Examples 2 to 5 of the present invention

g己方(phr^^^ SS)M Rubber a~~ ^Wepdmss^ Zinc Oxide Stearic Acid & Aging 2 3 4 70 70 70 30 30 30

Coupler halogen flame retardant

Brother (Sb203)

Sumitomo 50^A;fly·commercial|product name: NaUgard445;d·product name·_Κ6ν1αΓριι1ρ;ε·product name: f·trade name: Wingtack95; g·product name: Α巧89; : Name · DechloranPlas25. speak

First, the finished product prepared according to the formulations of Examples 1 to 5 above is processed by a rubber calender to be rolled out, and a polyethylene film is used as a bottom 16 1300086 material, and a roll is taken for convenient transportation. And storage. In use, the flame retardant layer of the rocket engine can be made by simply adding one step of cutting, affixing, expanding, and offering. The finished articles made according to the mating surfaces of Examples 1 to 5 have the relevant physical properties as shown in Table 4. Table 4 Test results of related physical properties

Heat transfer coefficient (Kcal/mh°C), in which the rubberized polyamide fiber is placed in the direction of the sheeting direction by the shear force of the calender drum, so that the rubber sheet is processed by the sheeting operation. The correlation between the two parallel and perpendicular directions is completely different, and the difference between the two is very obvious. It can be seen that the flame-retardant film made of the low-density rubber composition according to the present invention is soft in material and can be suitably laminated by a blown film expansion method (inflatable 17 l3〇〇086 teChnique). On a balloon made of butyl rubber, and then inflated from the balloon to expand the pressure, the film is closely attached to the inner wall of the missile casing to form a flame-retardant layer. At the same time, due to the strength of the rubber, it is also possible to manufacture the engine by different flame-retardant processing techniques such as the human method, the tape wrapping machine method or the medicine winding method. Ablative test. The finished rubber composition prepared according to the formulations of the above Examples i to 5 was aged by a hydraulic press in a flat mold at a condition of 12 〇〇 c, 2 hours, and 3 kgf/cm 2 and pressed to a thickness of 6 faces. Cooked film. According to the standard test method of astm E 285, Wei recorded: Here, the flame of a mixture of aeetylene and oxygen (acetylene flow rate i.7ft3/min, and oxygen 2.4 ft/min) is below the pattern. At 25.4 mm, the vertical name is rushed upward until the sample is burned through, so as to determine the ability of the _: layer (4) to withstand the flame flushing side. The results are shown in Table 5. It was confirmed by the resistance-to-burn test that the low-density rubber composition according to the present invention has a low-density property, and has excellent _-burning energy, and is more capable of sintering into a reverse, & It can be used as a heat-insulating and flame-retardant material for the inner wall of a rocket engine casing that makes a bribe. Table 5 Test results of resistance to burning surnames - ' ----- Example ----- —————— 1 2 3 ------— 4 5 (sQc/mmY (mm/sec) ^02~ ----~__ _〇ΛΙΙ ~7·85 —0.138 8.48 0_14 ~ ^936~ 0.132 ---—— ~1〇09~ Ι〇Ό9Γ; 18 1300086 Smoke concentration test: above according to embodiment 1 to implementation In the finished product of the rubber composition prepared by the formulation of Example 5, the finished products prepared by the formulations of Examples 1, 4 and 5 were subjected to the determination of the smoke concentration. Here, according to the ASTM E 662 standard Standard method for testing: Use the National Bureau of Standards (NBS) NBS Smoke Box to measure the concentration of smoke generated during the test sample to compare the smoke patterns of each sample. Table 6 shows the results of the determination of smoke concentration in Table 6. Example 1 4 Content of each component in the formula (phr) Halogen flame retardant 0 0 35 Antimony trioxide (Sb203) 0 0 10 Aluminium hydroxide (ai(oh) 3) 10 20 20 Aromatic polyamide fiber 12.5 12.5 12.5 Smoke (Dm) * 169 176 219 * Flame-burning, no unit. Test results show that when formula Excluding the use of _ sin fuel, the concentration of smoke can be greatly reduced. In the formulation without halogen fuel, the increase in the use of ai (〇h) 3 is similar to the smoke suppression effect. In the finished product of the rubber composition prepared according to the formulations of Examples 1 to 5, the products prepared in the formulations of Examples 1, 4 and 5 were selected to be 19 1300086, and the toxicity test was carried out. Here, the test is carried out in accordance with the method specified in the ASTME 1687 standard: the National Institute of Building Sciences Combustion Toxicity Test Apparatus (NIBS) is used to measure the burning of the film. Toxicity of smoke to compare the toxicity of smoke generated during ablation of each sample. Table 7 Results of smoke toxicity test Example 1 4 5 Content of each component in the formulation (phr) Halogen flame retardant 0 0 35 Antimony trioxide (Sb203) 0 0 10 氲Alumina (ai(oh)3) 10 20 20 Aromatic polyamide fiber 12.5 12.5 ^ 12.5 Smoke toxicity LD5G (gm/m3) 39.30 41.54 23.87 Test of toxicity of smoke after burning It is shown that in the formulation of each embodiment of the low-density rubber composition according to the present invention, the halogen flame retardant is replaced by Al(OH)3, which uses Al(OH)3 to suppress the poisoning effect and has a halogen-containing flame resistance. The formulation results of the film of the agent are far superior. While the present invention has been described above in terms of the preferred embodiments thereof, it is not intended to limit the invention, and it is intended that the invention may be modified and modified without departing from the spirit and scope of the invention. The patent protection scope of the invention is subject to the definition of the scope of the patent application attached to the specification. 20 1300086 [Simple description of the diagram] None [Main component symbol description]

Claims (1)

L3〇〇〇86 X. Shenqing Patent Range: L A low-density rubber composition suitable for use as a flame-retardant layer, wherein the flame-retardant layer has a density of less than about 1.0 gm/cm3, including: 50 phr ( 5% by weight of solid decyl ethyl ternary rubber (EPDMrubber) per 10,000 parts by weight of rubber; 〇phr to 50 phr of liquid decyl ethyl ternary rubber; 5 phr to 50 phr Aromatic polyamide fibers; % 〇·〇1 phr to 5 phr of sulfur; and 〇·〇1 phr to 5 phr of ripening accelerator. 2. The low-density rubber composition according to claim 1, wherein the sulfur is a colloidal sulfur yellow. 3. The low-density rubber composition of claim 1, wherein the sulfur is preferably used in an amount ranging from 〇5 phr to 2.5 phr. 4. The low-density rubber composition according to claim 1, wherein the curing agent is selected from the group consisting of N-t-butyl-2-phenylthiazole sulfinamide (like 邰_13卿 1- 2- benzothiazole sulfenamide), a combination of 4, 4,-dithio dimorpholine (4,4,-dithio dimorpholine) and mixtures thereof. 5. The low-density rubber composition of claim 4, wherein the n-tert-butyl-2-phenylthiazole sulfinamide is in an amount ranging from 〇.〇ι phr. Γ 3 6·As stated in the low-density rubber composition described in Item 5, wherein ▲ the preferred range of the second butyl-2-phenylthiazole sulfinamide is between 22 1300086 and 2 phr. . 7. The low-density rubber composition of claim 4, wherein the amount of the 4,4,-disulfide dipropofuran is between 0.01 phr and 3 phr. 8. The low-density rubber composition according to claim 7, wherein the preferred range of the 4, bismuth disulfide disulfide is between 0.05 phr and 2 phr. 9. If you apply for a patent scope! The low-density rubber composition described in the item further comprises an inorganic filler of from 5 phr to 1 phr. 10. The low density rubber composition of claim 9, wherein the inorganic filler is selected from the group consisting of sulphur dioxide, sulphuric acid, and mixtures thereof. U. The low-density rubber knee composition according to claim 9 further comprising: 1 1 Phr to 10 phr of a polydecene resin for use as a tackifier. 12. The low-density rubber composition according to the scope of the patent application, wherein the polydecene resin is preferably used in an amount ranging from 41) 111 > to 80}. 3. The low density rubber composition of claim i, wherein the solid thioethyl ternary rubber preferably has a range of between 55 phrs and 8 Torr. 4. If you apply for a patent scope! The low-density rubber composition described in the above, wherein the liquid thiol ethyl ternary rubber preferably ranges from 2 〇卩 ^ to "cutting ^. a density rubber composition in which the fiber diameter of the aromatic 16-branched amine fiber is between 10 μm and 14 μm. The low-density rubber composition according to claim 15 wherein the aromatic 23 1300086 The ratio of the length to the diameter of the steroid fiber of the steroid is about 500. 17. The low-density rubber composition according to the above-mentioned claim, wherein the preferred form of the polyamide fiber is pulp-like. 18方18· The low-density rubber composition as described in the patent application 帛η, the amount of the aromatic polyamidamide fiber in the range of 5/, pulp. U2〇phr 19 The preferred range of the fragrant polyamide fibers in the low-density rubber composition as described in claim 18 is between /, s, and phr phr. 1 () phril 5 twenty four