Flame-retardant silicon rubber, organic silicon rubber flame-retardant auxiliary agent and preparation method

Abstract

The invention relates to the field of flame retardants, in particular to flame-retardant silicon rubber, an organic silicon rubber flame-retardant aid and a preparation method. The flame retardant comprises the following components in parts by weight: 100 parts of polysiloxane; 50 to 400 parts of zinc-containing powder; 1-8 parts of a silane treating agent; and 100 to 2000 ppm of a platinum-containing compound. A platinum-containing compound, zinc-containing powder and a silane coupling agent are dispersed into polysiloxane to prepare paste, the ceramic forming ability of a platinum-containing catalyst is enhanced through the zinc-containing powder and the silane coupling agent, and the flame retardant effect of the platinum-containing compound is improved.

Description

Technical Field

[0001] The present invention relates to the field of flame retardants, and more specifically, to a flame retardant silicone rubber, an organic silicone rubber flame retardant additive and a preparation method thereof. Background Art

[0002] As a high-performance material, methyl vinyl silicone rubber has the characteristics of aging resistance, heat resistance, and flame retardancy due to its unique molecular chain structure. However, traditional methyl vinyl silicone rubber has obvious shortcomings in flame retardancy and cannot meet the UL94 V0 standard. Its insufficient flame retardancy limits its application and development in special product fields such as new energy, auto parts, and rail transit.

[0003] The technical solutions for improving the flame retardancy of silicone rubber in existing patents include the use of halogen flame retardants, phosphorus-nitrogen flame retardants, and platinum-containing compounds, but all of the above methods have obvious disadvantages. For halogen flame retardants, the amount of halogen flame retardants added is small, the flame retardant effect is good, and the cost performance is high. However, halogen flame retardants release toxic halogen compounds during combustion, which may affect the environment and human health. As EU and domestic laws and regulations become increasingly stringent, the use of halogen flame retardants in automotive parts, household appliances, etc. is restricted. Phosphorus-nitrogen flame retardants are not compatible with silicone rubber, resulting in poor mechanical strength of silicone rubber. At present, hydroxide flame retardants are commonly used in combination with platinum-containing compounds. Compared with platinum-containing compounds, commonly used hydroxides are fillers such as aluminum hydroxide and magnesium hydroxide, which have poor compatibility with silicone rubber. The more they are added, the higher the density and the worse the mechanical strength. At the same time, platinum-containing compounds have the advantages of small addition amount and high activity, but when the platinum-containing compounds are added in small amounts, the effect is not obvious. When added in large amounts, the cost is higher than other flame retardant fillers, and the commonly used addition amount is only in the ratio of 0.5 to 0.1 million, which is prone to insufficient mixing, resulting in problems such as insufficient flame retardancy of some products and unstable flame retardancy.

[0004] The invention provides an organic silicon rubber flame retardant auxiliary agent which has little influence on the density and mechanical strength of silicon rubber and has stable flame retardant performance, a preparation method thereof, and a flame retardant silicon rubber. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a flame retardant additive for silicone rubber, comprising:

[0006] 100 parts of polysiloxane;

[0007] Contains 50-400 parts of zinc powder, preferably 100-400 parts;

[0008] 1-8 parts of silane treatment agent;

[0009] The platinum content in the platinum-containing compound is 100-2000 ppm, preferably 200-2000 ppm, and more preferably 300-1500 ppm.

[0010] Furthermore, the zinc-containing powder is one or more of zinc oxide, zinc oxide, zinc carbonate or zinc borate.

[0011] Preferably, the zinc-containing powder is at least one of zinc oxide or zinc carbonate.

[0012] More preferably, the zinc-containing powder is zinc carbonate.

[0013] Furthermore, the organic silicone rubber flame retardant additive also includes 2-10 parts of an inhibitor.

[0014] Furthermore, the platinum-containing compound is at least one of platinum-loaded alumina, platinum-carbon, chloroplatinic acid, platinum chloride hydrate or Castell platinum catalyst.

[0015] Furthermore, the silane treating agent is at least one of monomethyltrimethoxysilane, dimethyldimethoxysilane, vinyltriethoxysilane, diphenyldimethoxysilane or phenyltrimethoxysilane.

[0016] Preferably, the silane treating agent is a phenyl-containing silane treating agent.

[0017] Furthermore, the polysiloxane is Wherein, R1-R3 are methyl, ethyl, trifluoropropyl, phenyl, hydroxyl or vinyl, X, Y, Z are average polymerization degrees, X is 10-14000, Y is 10-4000, and Z is 0-1400.

[0018] Furthermore, the inhibitor is a phosphorus-nitrogen inhibitor.

[0019] Furthermore, the inhibitor is preferably at least one of benzotriazole or triazole.

[0020] The present invention also provides a method for preparing a flame retardant additive for silicone rubber, comprising:

[0021] 100 parts of polysiloxane are added, 50-400 parts of zinc-containing compounds and 1-8 parts of silane treatment agents are added in multiple times for a first re-milling treatment, a platinum-containing compound with a platinum content of 100-2000 ppm is added, and kneading is performed until uniform to obtain the silicone rubber flame retardant additive.

[0022] Furthermore, the method further comprises adding 2-10 parts of an inhibitor to perform a second refining treatment after the high-temperature refining treatment and before adding 100-2000 ppm of a platinum-containing compound.

[0023] Furthermore, the first re-refining treatment conditions are: temperature 100-140° C., vacuum degree -0.05-0.07 MPa, and re-refining time 20-60 min.

[0024] Furthermore, the second refining treatment conditions are: temperature 100-140°C, time more than 20 minutes; preferably, the time is 20-40 minutes;

[0025] Further, before adding the platinum-containing compound, the temperature is lowered to below 70°C;

[0026] Furthermore, the kneading treatment conditions are: temperature below 70°C and time above 20 minutes; preferably, the time is 20-40 minutes.

[0027] The present invention also provides a flame retardant silicone rubber, comprising the above-mentioned organic silicone rubber flame retardant auxiliary agent, wherein the addition amount of the organic silicone rubber flame retardant auxiliary agent is 0.1-10 parts.

[0028] Beneficial effects of this patent:

[0029] 1. Disperse the platinum-containing compound, zinc-containing powder and silane coupling agent into polysiloxane to make a paste, and enhance the porcelain-forming ability of the platinum-containing compound and the flame retardant effect of the platinum-containing compound by using the zinc-containing powder and silane coupling agent.

[0030] 2. Add zinc powder. Zinc has a good catalytic effect on porcelain formation, and combined with platinum catalyst, it forms a porcelain layer faster and harder.

[0031] 3. Add silane treatment agent and improve the powder dispersibility and fluidity of the mixture through high temperature treatment, reducing the influence of powder on subsequent processing performance and mechanical properties.

[0032] 4. Platinum-containing compounds have better catalytic porcelain-forming effects in an oxygen-deficient or even oxygen-free environment. By adding preferred zinc carbonate and phenyl-containing silane treatment agents, zinc carbonate will degrade to form carbon dioxide, water and zinc oxide during the thermal combustion of the product, and the phenyl-containing silane treatment agent will consume more oxygen. Among them, zinc oxide has a good catalytic porcelain-forming effect, and carbon dioxide and water can reduce the oxygen concentration of combustible combustion and take away the combustion heat, thereby enhancing and optimizing the catalytic porcelain-forming effect of platinum-containing compounds and zinc-containing powders, and showing better flame retardant properties.

[0033] 5. The patented method can effectively improve the flame retardant effect of platinum-containing flame retardants, reduce the amount of organic silicon flame retardant additives used, and thus effectively reduce costs, or maintain the same amount of organic silicon flame retardant additives, reduce the amount of aluminum hydroxide flame retardant or other inorganic flame retardant powders added, and solve the problem of poor mechanical properties and poor demoulding due to excessive surface hydroxyl groups and poor compatibility of flame retardant powders. Using different amounts of organic silicon flame retardant additives can more flexibly prepare different types of flame retardant silicone rubber, making it have a wider range of product applicability.

[0034] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims, etc. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the appendix of the specific embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The embodiment of the present invention provides a flame retardant additive for silicone rubber, including: 100 parts of polysiloxane; 50-400 parts of zinc-containing powder; 1-8 parts of silane treatment agent; 100-2000 ppm of platinum-containing compound (referring to the mass concentration of platinum in the reaction system calculated as platinum).

[0037] In this scheme, a platinum-containing compound, a zinc-containing powder and a silane treatment agent are dispersed in polysiloxane to make a paste. The zinc-containing powder and the silane treatment agent are used to enhance the porcelain-forming ability of the platinum-containing catalyst, thereby greatly increasing the flame retardant effect of the platinum-containing compound.

[0038] In another embodiment of the present invention, the zinc-containing powder is one or more of zinc oxide, zinc carbonate or zinc borate.

[0039] The use of zinc-containing powder can catalyze polysiloxane to form silicon dioxide, which can be combined with a platinum-containing catalyst to form a ceramic layer faster and harder.

[0040] The zinc-containing powder is preferably added in an amount of 100-400 parts. The more the amount added, the better the matching effect. When the amount exceeds 400 parts, it is difficult to add.

[0041] In a preferred embodiment of the present invention, the zinc-containing compound is at least one of zinc carbonate or zinc oxide.

[0042] In a further preferred embodiment of the present invention, the zinc-containing compound is zinc carbonate.

[0043] The commonly used zinc carbonate is basic zinc carbonate, which will degrade to form carbon dioxide, water and zinc oxide during the combustion and heating process. Carbon dioxide and water can reduce the oxygen concentration of combustible combustion and take away the combustion heat. Zinc oxide also has a good catalytic porcelain-forming effect, further improving the flame retardant effect.

[0044] In another embodiment of the present invention, the organic silicone rubber flame retardant additive further includes 2-10 parts of an inhibitor.

[0045] The inhibitor can further inhibit the catalytic effect of the platinum-containing compound and extend the service life of the flame retardant.

[0046] In another embodiment of the present invention, the inhibitor is a phosphorus-nitrogen inhibitor, which can not only inhibit the catalytic effect of the platinum-containing compound, but also can be used as a phosphorus-nitrogen flame retardant, has a good flame retardant effect, and can further increase the service life of the flame retardant.

[0047] In another embodiment of the present invention, the inhibitor is at least one of benzotriazole or triazole.

[0048] In another embodiment of the present invention, the platinum-containing compound is at least one of platinum-loaded alumina, platinum-carbon, chloroplatinic acid, platinum chloride hydrate or Castell platinum catalyst.

[0049] The platinum-containing compound can be alumina loaded with platinum, platinum-carbon, and a platinum-containing catalyst, etc. The platinum-containing catalyst includes at least one of chloroplatinic acid or a Castor platinum catalyst. The platinum-containing compound can catalyze polysilicon to form a C-Si-O porcelain layer to prevent the flame from spreading further.

[0050] In another embodiment of the present invention, the silane treating agent is at least one of monomethyltrimethoxysilane, dimethyldimethoxysilane, vinyltriethoxysilane, diphenyldimethoxysilane or phenyltrimethoxysilane.

[0051] The use of silane treatment agent can not only treat the hydroxyl groups on the surface of zinc-containing powder, but also enhance the compatibility of zinc-containing powder with polysiloxane, improve the dispersibility and fluidity of the mixture, and reduce the influence of powder on subsequent processing performance and mechanical properties.

[0052] In a preferred embodiment of the present invention, the silane treating agent is a phenyl-containing silane treating agent.

[0053] Phenyl groups can attach to zinc-containing powders to promote the porcelain-forming speed of platinum-containing compounds and zinc-containing powders, and a small amount of addition can play a greater role. In addition, platinum-containing compounds have better catalytic porcelain-forming effects in an oxygen-deficient or even oxygen-free environment. Compared with the use of platinum-containing flame retardants alone, the phenyl rings of this application consume more oxygen during the combustion process, which can effectively reduce the oxygen content of combustibles during combustion, optimize the catalytic porcelain-forming effects of platinum-containing compounds and zinc-containing powders, and show better flame retardant effects.

[0054] In a more preferred embodiment of the present invention, the silane treatment agent is a phenyl-containing silane treatment agent, and the zinc-containing powder is zinc carbonate.

[0055] By adding zinc carbonate and phenylsiloxane, after high-temperature treatment, the phenyl ring is grafted onto the surface of the zinc carbonate powder, the dilution of the oxygen content by the generated carbon dioxide and water, and the consumption of more oxygen by the phenyl ring during the combustion process can effectively reduce the oxygen content of the combustible during combustion, optimize the catalytic ceramic effect of the platinum-containing compound and the zinc-containing powder, and show a better flame retardant effect. The silane treatment agent is selected as a phenyl-containing silane treatment agent, and the zinc-containing powder is zinc carbonate. The two have a synergistic effect and can achieve an effect of 1+1>2.

[0056] In another embodiment of the present invention, the structural formula of the polysiloxane is

[0057] Among them, R1-R3 are methyl, ethyl, trifluoropropyl, phenyl, hydroxyl or vinyl, X, Y, Z are average polymerization degrees, X is 10-14000, Y is 10-4000, and Z is 0-1400.

[0058] The present invention can utilize the polysiloxane as the base glue of the paste.

[0059] The flame retardant additive of the present application can effectively improve the flame retardant effect of the platinum-containing flame retardant, reduce the amount of organic silicon flame retardant additive used, and thus effectively reduce costs, or maintain the same amount of organic silicon flame retardant additive added, reduce the amount of aluminum hydroxide flame retardant or other inorganic flame retardant powder added, and solve the problem of poor mechanical properties and poor demoulding due to excessive surface hydroxyl groups and poor compatibility of excessive flame retardant powder. Using different amounts of organic silicon flame retardant additives can more flexibly prepare different types of flame retardant silicone rubber, making it have a wider range of product applicability.

[0060] In one embodiment of the present invention, a method for preparing a flame retardant additive for silicone rubber is provided, comprising:

[0061] 100 parts of polysiloxane are added, 50-400 parts of zinc-containing compounds and 1-8 parts of silane treatment agents are added in multiple times for a first re-milling treatment, 100-2000 ppm of platinum-containing compounds are added, and kneading is performed until uniform to obtain the silicone rubber flame retardant additive.

[0062] The method adds polysiloxane, zinc-containing powder, and silane treatment agent, and effectively treats the powder through the high-temperature treatment of the first re-refining, thereby improving the dispersibility of the powder, improving the fluidity of the mixture, and reducing the influence of the powder on subsequent processing performance and mechanical properties.

[0063] The method adds zinc-containing powder and silane treatment agent in multiple times and treats them under high-temperature refining, which can effectively enhance the dispersibility of the powder and make the treatment effect of the silane treatment agent better.

[0064] In another embodiment of the present invention, a second refining treatment is further performed by adding 2-10 parts of an inhibitor after the high-temperature refining treatment and before adding 100-2000 ppm of a platinum-containing compound.

[0065] After high-temperature refining, adding the inhibitor at a high temperature can fully melt and disperse the inhibitor, effectively exerting the inhibitory effect. Adding the platinum-containing compound allows the platinum-containing compound to be fully dispersed under the inhibitory protection.

[0066] Furthermore, the first refining treatment conditions are: temperature 100-140° C., vacuum degree -0.05-0.07 MPa, and refining time 20-60 min.

[0067] The re-milling temperature improves the dispersibility of the powder.

[0068] Furthermore, the second re-refining treatment conditions are: temperature 100-140° C., time more than 20 minutes.

[0069] When adding the inhibitor, the first re-refining temperature is maintained at 100-140°C, which can effectively improve the dispersibility of the inhibitor. The specific re-refining time is generally maintained for more than 20 minutes, as long as the re-refining can be uniform, but in order to save energy and time, the second re-refining time is preferably 20-40 minutes.

[0070] Furthermore, after the temperature is lowered to below 70° C., a platinum-containing compound is added, and the kneading treatment conditions are: temperature below 70° C. and time above 20 min.

[0071] On the one hand, adding the platinum-containing compound at this temperature allows the platinum-containing compound to be fully dispersed under the inhibition protection of benzotriazole; on the other hand, it can also reduce energy loss; and furthermore, it is safer to operate at this temperature. Generally, it can be lower than 70°C. As for the specific temperature to be lowered, there is no specific limit, as long as the raw rubber is in the rubber state.

[0072] The specific kneading time is generally maintained at more than 20 minutes, as long as the kneading can be uniform. However, in order to save energy and time, the kneading time is preferably 20-40 minutes.

[0073] The second re-milling and kneading process is carried out under normal pressure without vacuuming, because under vacuuming conditions, the inhibitor will be sucked away.

[0074] In another embodiment of the present invention, the multiple times refers to 3 to 10 times. The dispersibility of the powder can be effectively enhanced by adding multiple times.

[0075] In the preparation method of the present invention, the raw materials used are the same as the raw materials specified in the organic silicon rubber flame retardant auxiliary agent product.

[0076] In another embodiment of the present invention, a flame retardant additive for silicone rubber is prepared by the above method.

[0077] In another embodiment of the present invention, a flame retardant silicone rubber is provided, comprising the above-mentioned silicone rubber flame retardant additive, wherein the added amount of the silicone rubber flame retardant additive is 0.1-10 parts (by mass).

[0078] In order to describe the present invention more clearly, the following examples and comparative examples are used for illustration.

[0079] Example 1

[0080] 100 parts of 110 methyl vinyl silicone rubber (raw rubber) with a molecular weight of 70w and a vinyl content of 0.08%, 240 parts of zinc carbonate, 8 parts of Custer catalyst with a platinum content of 2.4% (the overall added platinum content is about 500ppm), 5 parts of diphenyldimethoxysilane, and 5 parts of benzotriazole.

[0081] Add raw rubber, zinc carbonate in 6 times and diphenyldimethoxysilane into a kneader, knead into a mass, heat to 120°C, set the vacuum degree to -0.06Mpa, evacuate at high temperature for 60 minutes, turn off the vacuum, add benzotriazole, knead for 30 minutes, cool to 50°C, add a platinum-containing compound and continue kneading. After 30 minutes, the silicone rubber flame retardant additive A can be obtained.

[0082] 1% (mass fraction) of silicone rubber flame retardant additive A was added to WRB-Z150-53A, and 1% of dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707, and the test pieces were cut into standard strips. The total burning time tf of the five strips was compared.

[0083] The actual addition amount is ≈0.65 parts of zinc carbonate, 5ppm of platinum catalyst, and 140ppm of benzotriazole.

[0084] Example 2

[0085] 5% of the silicone rubber flame retardant A obtained in Example 1 was added to WRB-Z150-53A, and 1% of the dipentadienyl vulcanizer was added. A 1 mm test piece was prepared at 170°C*10 min, and the test was performed according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0086] The actual addition amount is ≈3.3 parts of zinc carbonate, 25ppm of platinum catalyst, and 700ppm of benzotriazole.

[0087] Example 3

[0088] XHG151-50 (50HA ordinary compound rubber, sold by Zhejiang Xin'an Chemical Group Co., Ltd.) and WRB-Z150-53A were mixed at a ratio of 3:7, and 2% of the silicone rubber flame retardant additive A obtained in Example 1 was added, and 1% of the dipentadienyl vulcanizing agent was added. A 2 mm test piece was prepared at 170°C*10min, and the test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the 5 strips was compared.

[0089] Example 4

[0090] 100 parts of 110 methyl vinyl silicone rubber with a molecular weight of 70w and a vinyl content of 0.08%, 100 parts of zinc carbonate, 3 parts of Castor platinum catalyst with a platinum content of 2.4% (the platinum content is about 360ppm), 2 parts of diphenyldimethoxysilane, and 2 parts of benzotriazole.

[0091] The organic silicon rubber flame retardant additive B can be obtained according to the process of Example 1.

[0092] 1% silicone rubber flame retardant additive B was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0093] Example 5

[0094] 100 parts of 110 methyl vinyl silicone rubber with a molecular weight of 70w and a vinyl content of 0.08%, 100 parts of zinc carbonate, 12.5 parts of a Custer platinum catalyst with a platinum content of 2.4% (the platinum content is about 1500ppm), 5 parts of diphenyldimethoxysilane, and 10 parts of benzotriazole.

[0095] The organic silicon rubber flame retardant additive C can be obtained according to the process of Example 1.

[0096] 1% silicone rubber flame retardant additive C was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0097] Example 6

[0098] 100 parts of 110 methyl vinyl silicone rubber with a molecular weight of 70w and a vinyl content of 0.08%, 400 parts of zinc carbonate, 12.5 parts of Custer catalyst with a platinum content of 2.4% (the platinum content is about 600ppm), 8 parts of diphenyldimethoxysilane, and 5 parts of benzotriazole.

[0099] The organic silicon rubber flame retardant additive D can be obtained according to the process of Example 1.

[0100] 1% silicone rubber flame retardant additive D was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0101] Example 7

[0102] 100 parts of 110 methyl vinyl silicone rubber with a molecular weight of 70w and a vinyl content of 0.08%, 240 parts of zinc oxide, 8 parts of Custer catalyst with a platinum content of 2.4% (the overall added platinum content is about 500ppm), 5 parts of diphenyldimethoxysilane, and 5 parts of benzotriazole.

[0103] The organic silicone rubber flame retardant additive E can be obtained according to the process of Example 1.

[0104] Add 1% silicone rubber flame retardant additive to WRB-Z150-53A, add 1% dipentadienyl vulcanizer, make 2mm test pieces at 170℃*10min, test according to GB / T 10707, cut into standard specimens, and compare the total burning time tf of 5 specimens.

[0105] Example 8

[0106] 100 parts of 110 methyl vinyl silicone rubber with a molecular weight of 70w and a vinyl content of 0.08%, 240 parts of zinc carbonate, 8 parts of Custer catalyst with a platinum content of 2.4% (the overall added platinum content is about 500ppm), 5 parts of vinyl trimethoxy silane, and 5 parts of benzotriazole.

[0107] Add raw rubber and zinc carbonate into a kneading machine, knead into a mass, heat to 120°C, set the vacuum degree to -0.06Mpa, evacuate at high temperature for 60 minutes, turn off the vacuum, add benzotriazole, knead for 30 minutes, cool to below 70°C, add platinum compound and continue kneading. After 30 minutes, the silicone rubber flame retardant additive F can be obtained.

[0108] 1% silicone rubber flame retardant F was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0109] Example 9

[0110] 100 parts of methylphenyl silicone rubber with a molecular weight of 70w and a phenyl content of 0.08%, 50 parts of zinc borate, 0.53 parts of platinum chloride hydrate (the overall added platinum content is about 2000ppm), 1 part of dimethyldimethoxysilane, and 3 parts of triazole.

[0111] Add raw rubber, zinc borate and silane coupling agent into a kneader in two batches, knead into a mass, heat to 140°C, set the vacuum degree to -0.07Mpa, evacuate at high temperature for 20 minutes, turn off the vacuum, add benzotriazole, knead for 50 minutes, cool to 70°C, add platinum compound and continue kneading. After 60 minutes, the silicone rubber flame retardant additive Z can be obtained.

[0112] 1% organic silicone rubber flame retardant additive Z was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2mm test piece was made at 170℃*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the 5 strips was compared.

[0113] Example 10

[0114] Molecular weight 70w, 100 parts of hydroxypolysiloxane, 100 parts of zinc carbonate, 0.24 parts of platinum carbon compound with a platinum content of 30% (the overall added platinum content is about 360ppm), 3 parts of phenyltrimethoxysilane, and 5 parts of benzotriazole.

[0115] Add raw rubber, zinc carbonate and silane coupling agent into a kneader three times, knead into a mass, heat to 100°C, set the vacuum degree to -0.05Mpa, evacuate at high temperature for 40 minutes, turn off the vacuum, add benzotriazole, knead for 60 minutes, cool to 30°C, add platinum compound and continue kneading, and obtain silicone rubber flame retardant additive X after 45 minutes.

[0116] Add 1% silicone rubber flame retardant X to WRB-Z150-53A, add 1% dipentadienyl vulcanizer, make 2mm test pieces at 170℃*10min, test according to GB / T 10707, cut into standard specimens, and compare the total burning time tf of 5 specimens.

[0117] Embodiment 11

[0118] Compared with Example 1, the inhibitor benzotriazole was not added, and the other conditions were the same as those in Example 1.

[0119] Comparative Example 1

[0120] According to the raw materials in the formula of Example 1, zinc carbonate and diphenyldimethoxysilane are removed and replaced with silicon powder, and the organic silicone rubber flame retardant additive I is obtained according to the process of Example 1.

[0121] First, XHG151-50 (50HA ordinary compound rubber, sold by Zhejiang Xin'an Chemical Group Co., Ltd.) and WRB-Z150-53A were mixed at a ratio of 3:7, and then 2% of the silicone flame retardant additive I was taken according to the steps of the evaluation method, and 1% of the dipentadienyl vulcanizer was added. A 2mm test piece was made at 170℃*10min, and the test was carried out according to GB / T 10707. The test was cut into standard strips, and the total burning time tf of the 5 strips was compared.

[0122] Comparative Example 2

[0123] 1% silicone rubber flame retardant additive I was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0124] Comparative Example 3

[0125] The platinum catalyst in Example 1 is removed and the organic silicone rubber flame retardant additive G can be obtained according to the process of Example 1.

[0126] 1% silicone rubber flame retardant G was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0127] Comparative Example 4

[0128] The diphenyldimethoxysilane in Example 1 is removed and replaced with silicon powder, and the silicone rubber flame retardant additive H can be obtained according to the process of Example 1.

[0129] 1% silicone rubber flame retardant H was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0130] Comparative Example 5

[0131] The zinc carbonate in Example 1 is removed and replaced with silicon powder, and the organic silicone rubber flame retardant additive G can be obtained according to the process of Example 1.

[0132] 1% silicone rubber flame retardant G was added to WRB-Z150-53A, and 1% dipentadienyl vulcanizer was added. A 2 mm test piece was made at 170°C*10min. The test was carried out according to GB / T 10707. The test pieces were cut into standard strips, and the total burning time tf of the five strips was compared.

[0133] Among them, the commercially available WRB-Z150-53A selected in the embodiments and comparative examples is a flame retardant silicone rubber with aluminum hydroxide as the main filler, with a hardness of 50HA, a density of 1.43g / cm3, a tensile strength of 5.1 / elongation of 360% / tear strength of 14N / mm, sold by Zhejiang Xin'an Chemical Group Co., Ltd.

[0134] The mechanical properties of the flame retardant silicone rubber WRB-Z150-53A, Examples 1-3 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0135] Table 1. Mechanical properties

[0136]

[0137] Table 2 is the test results of the embodiments and comparative examples.

[0138]

[0139]

[0140] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A flame retardant additive for silicone rubber, characterized in that: include: 100 parts of polysiloxane; Contains 50-400 parts of zinc powder, preferably 100-400 parts; 1-8 parts of silane treatment agent; The platinum content in the platinum-containing compound is 100-2000 ppm, preferably 200-2000 ppm, and more preferably 300-1500 ppm.

2. The flame retardant additive for silicone rubber according to claim 1, characterized in that: The zinc-containing powder is one or more of zinc oxide, zinc carbonate or zinc borate; Preferably, the zinc-containing powder is at least one of zinc carbonate or zinc oxide. More preferably, the zinc-containing powder is zinc carbonate.

3. The flame retardant additive for silicone rubber according to claim 1, characterized in that: Also includes 2-10 parts of inhibitor.

4. The flame retardant additive for silicone rubber according to claim 1, characterized in that: The silane treatment agent is at least one of monomethyltrimethoxysilane, dimethyldimethoxysilane, vinyltriethoxysilane, diphenyldimethoxysilane or phenyltrimethoxysilane; Preferably, the silane treating agent is a phenyl-containing silane treating agent.

5. The flame retardant additive for silicone rubber according to claim 1, characterized in that: The polysiloxane is Wherein R1-R3 are methyl, ethyl, trifluoropropyl, phenyl, hydroxyl or vinyl, X, Y, Z are average polymerization degrees, X is 10-14000, Y is 10-4000, and Z is 0-1400; And / or the platinum-containing compound is at least one of platinum-loaded alumina, platinum-carbon, chloroplatinic acid, platinum chloride hydrate or Castell platinum catalyst.

6. The flame retardant additive for silicone rubber according to claim 3, characterized in that: The inhibitor is a phosphorus-nitrogen inhibitor; The inhibitor is preferably at least one of benzotriazole or triazole.

7. A method for preparing a flame retardant additive for silicone rubber, characterized in that: include: 100 parts of polysiloxane are added, 50-400 parts of zinc-containing compounds and 1-8 parts of silane treatment agents are added in multiple times for a first re-milling treatment, a platinum-containing compound containing 100-2000 ppm of platinum is added, and kneading is performed until uniform to obtain the silicone rubber flame retardant additive.

8. The preparation method according to claim 7, characterized in that: The method also includes adding 2-10 parts of an inhibitor to perform a second refining treatment after the high-temperature refining treatment and before adding 100-2000 ppm of a platinum-containing compound.

9. The preparation method according to claim 8, characterized in that: The first refining treatment conditions are: temperature 100-140°C, vacuum degree -0.05-0.07Mpa, refining time 20-60min; and / or the second refining treatment conditions are: temperature 100-140°C, time more than 20 minutes; preferably, the time is 20-40 minutes; and / or before adding the platinum-containing compound, cooling to below 70°C; And / or the kneading treatment conditions are: temperature below 70°C and time above 20 minutes; preferably, the time is 20-40 minutes.

10. A flame retardant silicone rubber, comprising the silicone rubber flame retardant additive according to any one of claims 1 to 6, wherein the added amount of the silicone rubber flame retardant additive is 0.1 to 10 parts.

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