Nitrosamine-free foaming rubber and plastic material and preparation method thereof

Abstract

The invention provides a foamed rubber and plastic material without nitrosamine and a preparation method thereof, and relates to the technical field of foamed rubber and plastic materials. The foamed rubber-plastic material free of nitrosamine is prepared from nitrile rubber, polyvinyl chloride, chlorinated polyethylene, chlorinated paraffin, epoxidized soybean oil, aluminum hydroxide, a foaming agent, a foaming promoter, carbon black, an organic silicon modifier, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, sulfur, an anti-aging agent, a vulcanization accelerator and the like. The vulcanization accelerator provided by the invention is an accelerator ZBEC and an accelerator TBzTD. According to the invention, by adjusting the composition and proportion of the raw materials and combining the use of the composite vulcanization accelerator, the preparation of the foamed rubber and plastic material without nitrosamine is realized, and the environmental protection property and safety of the product are improved.

Description

Technical Field

[0001] The invention relates to the technical field of foamed rubber and plastic materials, and in particular to a foamed rubber and plastic material free of nitrosamines and a preparation method thereof. Background Art

[0002] Foamed rubber and plastic materials are a type of thermal insulation material made of materials such as rubber and polyvinyl chloride (PVC). Through micro-foaming technology, countless closed pore structures are formed inside the material. These pores can lock in inert air with ultra-low thermal conductivity, thereby effectively preventing heat transfer. Foamed rubber and plastic materials have excellent thermal insulation properties, and the thermal conductivity coefficient is usually around 0.024W / m·K, which can effectively reduce energy waste. In addition, foamed rubber and plastic materials also have good fire resistance, can reach the flame retardant B1 level, and the oxygen index is greater than 35, which meets the building fire protection regulations. The closed-cell structure of foamed rubber and plastic materials enables the material to have excellent resistance to water vapor penetration and prevent condensation. At the same time, it does not contain harmful substances such as CFCs, formaldehyde and heavy metals, and is environmentally friendly. It is widely used in HVAC systems, refrigeration equipment, hot water pipes and building walls, etc., which can not only improve energy utilization efficiency, but also improve indoor environmental quality.

[0003] Vulcanization accelerator is one of the important additives in foamed rubber and plastic materials. Vulcanization accelerator can accelerate the vulcanization reaction and form more crosslinks between rubber molecules, thereby enhancing the mechanical strength, heat resistance and aging resistance of the material. Vulcanization accelerator can significantly shorten the vulcanization time, improve production efficiency, and improve the mechanical properties and durability of the material by increasing the crosslinking points between rubber molecules. In addition, the use of accelerators can reduce processing temperature and pressure and reduce energy consumption. Amino vulcanization accelerator is a common accelerator. Amino vulcanization accelerators have unique advantages in the rubber vulcanization process. First, their vulcanization speed is moderate, providing a good processing window and reducing the risk of scorch. Secondly, amino vulcanization accelerators show excellent stability under high temperature conditions and are suitable for rubber products that require high temperature processing. In addition, vulcanized rubber using amino vulcanization accelerators usually has good physical and mechanical properties, such as tensile strength, elasticity and wear resistance. Finally, amino vulcanization accelerators can be used in conjunction with other types of accelerators (such as thiazoles and sulfenamides) to further optimize the vulcanization system and improve vulcanization efficiency and product performance. These advantages make amino vulcanization accelerators very useful in applications that require a balance between vulcanization speed and physical properties. Therefore, amino vulcanization accelerators are one of the most commonly used vulcanization accelerators in the production of rubber and plastic materials. However, in the processing of rubber and plastic products, the use of amino vulcanization accelerators is prone to produce carcinogenic N-nitrosamines, which have a great adverse effect on human health, and it is necessary to accurately control the ratio between amino vulcanization accelerators and other accelerators and auxiliary materials, otherwise it is very easy to lead to a decline in the overall quality of the product.

[0004] The Chinese invention patent with the publication number CN111548571A discloses an environmentally friendly rubber compound, including the following components by mass: butyl rubber: 40-80 parts: bromobutyl rubber: 20-45 parts: zinc oxide: 2-9 parts; natural rubber: 20-35 parts: stearic acid 0.5-3 parts; antioxidant 0.5-1.5 parts; N550 carbon black: 30-60 parts; environmentally friendly accelerator: 3-5 parts; flow aid 1-3 parts; vulcanizer: 0.5-1.0 parts. The environmentally friendly rubber compound provided by it adopts a variety of environmentally friendly accelerators mixed in a specific proportion, does not produce carcinogenic substances such as nitrosamines during the vulcanization process, and can improve the vulcanization speed and vulcanization degree; the product appearance quality is excellent; nano-active zinc oxide replaces zinc oxide in the traditional formula, which can reduce the use of lead-containing zinc oxide in the formula, making the rubber mixed rubber and rubber-plastic products produced more environmentally friendly. However, this solution provides a rubber product and is not suitable for the production of rubber and plastic materials.

[0005] Therefore, it is necessary to provide a foamed rubber-plastic material that does not contain nitrosamines and a preparation method thereof to overcome the problems existing in the prior art. Summary of the invention

[0006] In view of this, the present invention provides a foamed rubber-plastic material free of nitrosamines and a preparation method thereof. The method uses a specific composite vulcanization accelerator in combination with a specific preparation process, so that nitrosamines are not generated and released during the foaming process of the foamed rubber-plastic material.

[0007] The nitrosamine-free foamed rubber-plastic material of the present invention comprises the following raw materials in parts by weight:

[0008] 7-13 parts of nitrile rubber, 5-9 parts of polyvinyl chloride, 6-10 parts of chlorinated polyethylene, 16-20 parts of chlorinated paraffin, 0.8-1.3 parts of epoxidized soybean oil, 22-26 parts of aluminum hydroxide, 10-15 parts of foaming agent, 5-8 parts of foaming aid, 1.1-1.7 parts of carbon black, 5-8 parts of silicone modifier, 4-5 parts of antimony trioxide, 0.5-1 part of solid paraffin, 0.1-0.5 parts of stearic acid, 0.3-0.6 parts of polyethylene glycol, 0.2-0.5 parts of sulfur, 0.04-0.08 parts of antioxidant, and 0.8-2 parts of vulcanization accelerator.

[0009] Furthermore, the foaming agent is an AC foaming agent.

[0010] Furthermore, the foaming aid is one or more of urea ester, adipic acid, and salicylic acid. Preferably, the foaming aid is urea ester.

[0011] Furthermore, the organosilicon modifier is one or more of γ-mercaptopropyltriethoxysilane, aminopropyltrimethoxysilane, and γ-glycidyloxypropyltrimethoxysilane. Preferably, the organosilicon modifier is aminopropyltrimethoxysilane.

[0012] Furthermore, the antioxidant is antioxidant 4020.

[0013] Furthermore, the vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 5:1.

[0014] Furthermore, the mass ratio of the first portion of aluminum hydroxide to the second portion of aluminum hydroxide is 1:1, and the mass ratio of the first portion of chlorinated paraffin to the second portion of chlorinated paraffin is 1.5:1.

[0015] The present invention also provides a method for preparing the nitrosamine-free foamed rubber-plastic material, which specifically comprises the following steps:

[0016] S1, put nitrile rubber, polyvinyl chloride, chlorinated polyethylene, epoxy soybean oil, carbon black, organosilicon modifier, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, antioxidant into an internal mixer and mix, then add the first portion of aluminum hydroxide and the first portion of chlorinated paraffin and perform a first internal mixer, then add the second portion of aluminum hydroxide and the second portion of chlorinated paraffin and perform a second internal mixer, after rubber mixing is completed, discharge the rubber, slice after opening the mixing, and stack for 48 hours after cooling to obtain material No. 1;

[0017] S2, adding sulfur, vulcanization accelerator, foaming agent and foaming aid to the No. 1 material, mixing evenly after refining, and then slicing to obtain No. 2 material;

[0018] S3, extruding the No. 2 material in an extruder to obtain a molding rubber, and cooling the molding rubber after free foaming to obtain a foamed rubber-plastic material free of nitrosamines.

[0019] Furthermore, the first banburying temperature is 135° C., the first banburying time is 2 to 3 minutes, the second banburying temperature is 150° C., and the second banburying time is 7 to 9 minutes.

[0020] Further, the debinding temperature is 168° C. to 175° C. Preferably, the debinding temperature is 168° C.

[0021] Furthermore, the thickness of the No. 1 material film is 8 mm, and the thickness of the No. 2 material film is 9 mm.

[0022] Furthermore, the extruder has a feeding section temperature of 25°C to 30°C, a plasticizing section temperature of 32°C to 35°C, a die section temperature of 35°C to 40°C, a die pressure of 0.4 to 0.5 MPa, and a rotation speed of 15 to 20 r / min.

[0023] Further, the foaming furnace is divided into seven-zone control or six-zone control according to the temperature. Preferably, the foaming furnace is divided into six-zone control according to the temperature.

[0024] Furthermore, the temperatures of the zones of the foaming furnace are set as follows: zone one 100°C to 120°C, zone two 120°C to 125°C, zone three 125°C to 135°C, zone four 135°C to 145°C, zone five 145°C to 160°C, and zone six 160°C to 175°C.

[0025] Furthermore, the initial transmission speed of the first zone of the foaming furnace is 1.1-1.3 m / min, and the line speeds of the remaining zones are adjusted according to the foaming conditions.

[0026] Furthermore, the molding rubber is cooled by air after free foaming, and the cooling distance is 90m.

[0027] Furthermore, after the free foaming is completed and cooled, the steps of cutting and packaging are also included.

[0028] The foamed rubber-plastic material of the invention is used for preparing conventional heat-insulating materials, sound-insulating materials and shock-proof materials.

[0029] Compared with the prior art, the beneficial technical effects of the present invention are:

[0030] The invention uses accelerator ZBEC as a main vulcanization accelerator, accelerator TBzTD as an auxiliary vulcanization accelerator, and uses auxiliaries such as an organosilicon modifier and an antioxidant, thereby achieving the preparation of a product free of nitrosamines while ensuring good comprehensive performance of the product, thereby improving the environmental protection and safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] Figure 1 The present invention is a flow chart of the preparation process of the foamed rubber and plastic material. DETAILED DESCRIPTION

[0033] The present invention provides a nitrosamine-free foamed rubber-plastic material, comprising the following raw materials in parts by weight:

[0034] 7-13 parts of nitrile rubber, 5-9 parts of polyvinyl chloride, 6-10 parts of chlorinated polyethylene, 16-20 parts of chlorinated paraffin, 0.8-1.3 parts of epoxidized soybean oil, 22-26 parts of aluminum hydroxide, 10-15 parts of foaming agent, 5-8 parts of foaming aid, 1.1-1.7 parts of carbon black, 5-8 parts of silicone modifier, 4-5 parts of antimony trioxide, 0.5-1 part of solid paraffin, 0.1-0.5 parts of stearic acid, 0.3-0.6 parts of polyethylene glycol, 0.2-0.5 parts of sulfur, 0.04-0.08 parts of antioxidant, and 0.8-2 parts of vulcanization accelerator.

[0035] In one embodiment, the blowing agent is an AC blowing agent.

[0036] In one embodiment, the foaming aid is one or more of urea ester, adipic acid, and salicylic acid.

[0037] In one embodiment, the foaming aid is urea ester.

[0038] In one embodiment, the organosilicon modifier is one or more of γ-mercaptopropyltriethoxysilane, aminopropyltrimethoxysilane, and γ-glycidyloxypropyltrimethoxysilane.

[0039] In one embodiment, the organosilicon modifier is aminopropyltrimethoxysilane.

[0040] Organic silicon modifiers are widely used in foamed rubber and plastic materials. By using organic silicon modifiers, the high temperature resistance, UV resistance, oxidation resistance, and chemical corrosion resistance of foamed rubber and plastic materials can be significantly improved, thereby extending the service life of the materials. In the present invention, the specific organic silicon modifier can enhance the comprehensive performance of the material.

[0041] In one embodiment, the antioxidant is antioxidant 4020.

[0042] In one embodiment, the vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 5:1.

[0043] Accelerator ZBEC (zinc dibenzyl dithiocarbamate) is an organic zinc compound and also a safe secondary amino dithiocarbamate accelerator. Among all dithiocarbamate accelerators, ZBEC has a long anti-scorch performance and good operational safety, so the present invention selects accelerator ZBEC as the main accelerator. However, in the technical scheme of the present invention, only using accelerator ZBEC has a poor foaming effect, the surface of the obtained finished product is rough, and the product cannot meet the quality requirements of the factory. Therefore, it is necessary to use other types of accelerators to assist it to ensure the comprehensive performance of the product.

[0044] The accelerator TBzTD (tetrabenzylthiuram disulfide) is a rubber vulcanization accelerator, mainly used to replace traditional thiuram accelerators such as TMTD and TETD. It is used as a replica vulcanization accelerator in the preparation process of the foamed rubber and plastic material of the present invention to make up for the shortcomings of the accelerator ZBEC.

[0045] Therefore, the present invention strictly limits the composition and ratio of the accelerator to ensure a good vulcanization acceleration effect, thereby ensuring that the finished product has good comprehensive properties.

[0046] In one embodiment, the mass ratio of the first portion of aluminum hydroxide to the second portion of aluminum hydroxide is 1:1, and the mass ratio of the first portion of chlorinated paraffin to the second portion of chlorinated paraffin is 1.5:1.

[0047] The present invention also provides a method for preparing the nitrosamine-free foamed rubber-plastic material, which specifically comprises the following steps:

[0048] S1, put nitrile rubber, polyvinyl chloride, chlorinated polyethylene, epoxy soybean oil, carbon black, organosilicon modifier, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, antioxidant into an internal mixer and mix, then add the first portion of aluminum hydroxide and the first portion of chlorinated paraffin and perform a first internal mixer, then add the second portion of aluminum hydroxide and the second portion of chlorinated paraffin and perform a second internal mixer, after rubber mixing is completed, discharge the rubber, slice after opening the mixing, and stack for 48 hours after cooling to obtain material No. 1;

[0049] S2, adding sulfur, vulcanization accelerator, foaming agent and foaming aid to the No. 1 material, mixing evenly after refining, and then slicing to obtain No. 2 material;

[0050] S3, extruding the No. 2 material in an extruder to obtain a molding rubber, and cooling the molding rubber after free foaming to obtain a foamed rubber-plastic material free of nitrosamines.

[0051] In one embodiment, the first banburying temperature is 135° C., the first banburying time is 2 to 3 minutes, the second banburying temperature is 150° C., and the second banburying time is 7 to 9 minutes.

[0052] In one embodiment, the debinding temperature is 168°C to 175°C.

[0053] In one embodiment, the debinding temperature is 168°C.

[0054] In one embodiment, the thickness of the No. 1 material film is 8 mm, and the thickness of the No. 2 material film is 9 mm.

[0055] In one embodiment, the extruder feeding section temperature is 25°C to 30°C, the plasticizing section temperature is 32°C to 35°C, the die section temperature is 35°C to 40°C, the die pressure is 0.4 to 0.5 MPa, and the rotation speed is 15 to 20 r / min.

[0056] In one embodiment, the foaming furnace is divided into seven zones or six zones according to the temperature. In one embodiment, the foaming furnace is divided into six zones according to the temperature.

[0057] In one embodiment, the temperature of each zone of the foaming furnace is set as follows: zone one 100℃~120℃, zone two 120℃~125℃, zone three 125℃~135℃, zone four 135℃~145℃, zone five 145℃~160℃, zone six 160℃~175℃.

[0058] In one embodiment, the initial transmission speed of the first zone of the foaming furnace is 1.1 to 1.3 m / min, and the linear speeds of the remaining zones are adjusted according to the foaming conditions. The present invention only limits the initial transmission speed of the first zone of the foaming furnace, and does not limit the transmission speeds of the subsequent remaining zones. In actual production, the foaming conditions of the materials are not the same due to factors such as the composition and ratio of the raw materials. Therefore, the temperature and transmission speed of each zone need to be flexibly adjusted according to the actual foaming conditions to ensure the foaming quality and dimensional stability of the material. Optimization and adjustment based on actual conditions can also improve the adaptability and flexibility of the process to meet different production needs.

[0059] In one embodiment, the molding adhesive is cooled by air after free foaming, and the cooling distance is 90m.

[0060] In one embodiment, after the free foaming is completed and cooled, the process further includes cutting and packaging steps.

[0061] The foamed rubber-plastic material of the invention is used for preparing conventional heat-insulating materials, sound-insulating materials and shock-proof materials.

[0062] The technical solution provided by the present invention is further described below in conjunction with embodiments.

[0063] Embodiment 1 A foamed rubber-plastic material free of nitrosamines comprises the following raw materials in parts by weight:

[0064] 11 parts of nitrile rubber, 6 parts of polyvinyl chloride, 8 parts of chlorinated polyethylene, 18 parts of chlorinated paraffin, 1 part of epoxy soybean oil, 24 parts of aluminum hydroxide, 12 parts of AC foaming agent, 6 parts of urea grease, 1.45 parts of carbon black, 5.8 parts of aminopropyl trimethoxy silane, 4 parts of antimony trioxide, 0.6 parts of solid paraffin, 0.3 parts of stearic acid, 0.5 parts of polyethylene glycol, 0.3 parts of sulfur, 0.05 parts of antioxidant 4020, 1 part of vulcanization accelerator;

[0065] The vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 5:1.

[0066] The preparation method of the foamed rubber-plastic material free of nitrosamines comprises the following steps:

[0067] S1. Put nitrile rubber, polyvinyl chloride, chlorinated polyethylene, epoxy soybean oil, carbon black, aminopropyl trimethoxysilane, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, and antioxidant 4020 into an internal mixer and mix them. Then add the first portion of aluminum hydroxide and the first portion of chlorinated paraffin and mix them at 135°C for 2.5 minutes. Then add the second portion of aluminum hydroxide and the second portion of chlorinated paraffin and mix them at 150°C for 7 minutes. When the mixing temperature reaches 168°C, discharge the rubber onto an open mixer, slice it after mixing, cool it, and stack it for 48 hours to obtain material No. 1 with a thickness of 8 mm, a width of 500 mm, and a length of 600 mm.

[0068] The mass ratio of the first portion of aluminum hydroxide to the second portion of aluminum hydroxide is 1:1, and the mass ratio of the first portion of chlorinated paraffin to the second portion of chlorinated paraffin is 1.5:1;

[0069] S2, adding sulfur, vulcanization accelerator, AC foaming agent and urea fat to the No. 1 material, mixing and slicing after refining, to obtain a No. 2 material with a thickness of 9 mm, a width of 250 mm and a length of 25000 mm;

[0070] S3, extruding the No. 2 material in an extruder to obtain a molding rubber, and the molding rubber is cooled by air through a transmission mesh belt after free foaming, and the cooling distance is 90m to obtain a foamed rubber-plastic material free of nitrosamines;

[0071] The extruder parameters are as follows: the feeding section temperature is 25°C; the plasticizing section temperature is 32°C; the head section temperature is 35°C;

[0072] The temperature of each zone of the foaming furnace is set as follows: zone 1 100°C, zone 2 125°C, zone 3 135°C, zone 4 145°C, zone 5 160°C, zone 6 175°C, and the initial transmission speed of zone 1 is 1.3m / min;

[0073] S5. The cooled products are sent to the cutting machine for cutting, cut into the required size, and packaged for storage.

[0074] Embodiment 2 A foamed rubber-plastic material free of nitrosamines comprises the following raw materials in parts by weight:

[0075] 10 parts of nitrile rubber, 8 parts of polyvinyl chloride, 7 parts of chlorinated polyethylene, 17 parts of chlorinated paraffin, 1 part of epoxy soybean oil, 23 parts of aluminum hydroxide, 12 parts of AC foaming agent, 6 parts of urea grease, 1.4 parts of carbon black, 6 parts of aminopropyl trimethoxy silane, 5 parts of antimony trioxide, 0.75 parts of solid paraffin, 0.2 parts of stearic acid, 0.3 parts of polyethylene glycol, 0.3 parts of sulfur, 0.05 parts of antioxidant 4020, and 2 parts of vulcanization accelerator;

[0076] The vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 5:1.

[0077] The preparation method of the foamed rubber-plastic material free of nitrosamines comprises the following steps:

[0078] S1. Put nitrile rubber, polyvinyl chloride, chlorinated polyethylene, epoxy soybean oil, carbon black, aminopropyl trimethoxysilane, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, and antioxidant 4020 into an internal mixer and mix them. Then add the first portion of aluminum hydroxide and the first portion of chlorinated paraffin and mix them at 135°C for 2.5 minutes. Then add the second portion of aluminum hydroxide and the second portion of chlorinated paraffin and mix them at 150°C for 7 minutes. When the mixing temperature reaches 168°C, discharge the rubber onto an open mixer, slice it after mixing, cool it, and stack it for 48 hours to obtain material No. 1 with a thickness of 8 mm, a width of 500 mm, and a length of 600 mm.

[0079] The mass ratio of the first portion of aluminum hydroxide to the second portion of aluminum hydroxide is 1:1, and the mass ratio of the first portion of chlorinated paraffin to the second portion of chlorinated paraffin is 1.5:1;

[0080] S2, adding sulfur, vulcanization accelerator, AC foaming agent and urea fat to the No. 1 material, mixing and slicing after refining, to obtain a No. 2 material with a thickness of 9 mm, a width of 250 mm and a length of 25000 mm;

[0081] S3, extruding the No. 2 material in an extruder to obtain a molding rubber, and the molding rubber is cooled by air through a transmission mesh belt after free foaming, and the cooling distance is 90m to obtain a foamed rubber-plastic material free of nitrosamines;

[0082] The extruder parameters are as follows: the feeding section temperature is 30°C; the plasticizing section temperature is 35°C; the head section temperature is 35°C;

[0083] The temperature of each zone of the foaming furnace is set as follows: zone 1 120°C, zone 2 125°C, zone 3 130°C, zone 4 143°C, zone 5 158°C, zone 6 175°C, and the initial transmission speed of zone 1 is 1.2m / min;

[0084] S5. The cooled products are sent to the cutting machine for cutting, cut into the required size, and packaged for storage.

[0085] Embodiment 3 A foamed rubber-plastic material free of nitrosamines comprises the following raw materials in parts by weight:

[0086] 10 parts of nitrile rubber, 7 parts of polyvinyl chloride, 8 parts of chlorinated polyethylene, 17 parts of chlorinated paraffin, 1 part of epoxidized soybean oil, 23.5 parts of aluminum hydroxide, 12 parts of AC foaming agent, 6 parts of urea grease, 1.5 parts of carbon black, 5.5 parts of aminopropyl trimethoxy silane, 5 parts of antimony trioxide, 0.7 parts of solid paraffin, 0.35 parts of stearic acid, 0.5 parts of polyethylene glycol, 0.4 parts of sulfur, 0.05 parts of antioxidant 4020, and 1.5 parts of vulcanization accelerator;

[0087] The vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 5:1.

[0088] The preparation method of the foamed rubber-plastic material free of nitrosamines comprises the following steps:

[0089] S1. Put nitrile rubber, polyvinyl chloride, chlorinated polyethylene, epoxy soybean oil, carbon black, aminopropyl trimethoxysilane, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, and antioxidant 4020 into an internal mixer and mix them. Then add the first portion of aluminum hydroxide and the first portion of chlorinated paraffin and mix them at 135°C for 2.5 minutes. Then add the second portion of aluminum hydroxide and the second portion of chlorinated paraffin and mix them at 150°C for 7 minutes. When the mixing temperature reaches 168°C, discharge the rubber onto an open mixer, slice it after mixing, cool it, and stack it for 48 hours to obtain material No. 1 with a thickness of 8 mm, a width of 500 mm, and a length of 600 mm.

[0090] The mass ratio of the first portion of aluminum hydroxide to the second portion of aluminum hydroxide is 1:1, and the mass ratio of the first portion of chlorinated paraffin to the second portion of chlorinated paraffin is 1.5:1;

[0091] S2, adding sulfur, vulcanization accelerator, AC foaming agent and urea fat to the No. 1 material, mixing and slicing after refining, to obtain a No. 2 material with a thickness of 9 mm, a width of 250 mm and a length of 25000 mm;

[0092] S3, extruding the No. 2 material in an extruder to obtain a molding rubber, and the molding rubber is cooled by air through a transmission mesh belt after free foaming, and the cooling distance is 90m to obtain a foamed rubber-plastic material free of nitrosamines;

[0093] The extruder parameters are as follows: the feeding section temperature is 25°C; the plasticizing section temperature is 35°C; the head section temperature is 40°C;

[0094] The temperature of each zone of the foaming furnace is set as follows: zone 1 115°C, zone 2 125°C, zone 3 135°C, zone 4 145°C, zone 5 155°C, zone 6 173°C, and the initial transmission speed of zone 1 is 1.1 m / min;

[0095] S5. The cooled products are sent to the cutting machine for cutting, cut into the required size, and packaged for storage.

[0096] Comparative Example 1

[0097] Same as Example 3, except that the accelerator is accelerator ZBEC.

[0098] Comparative Example 2

[0099] Same as Example 3, except that the accelerator ZBEC is replaced by an equal amount of accelerator PZ.

[0100] Comparative Example 3

[0101] Same as Example 3, except that the accelerator TBzTD is replaced by an equal amount of accelerator PZ.

[0102] Comparative Example 4

[0103] The same as Example 3, except that the vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 2:1.

[0104] Comparative Example 5

[0105] The same as Example 3, except that the vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 8:1.

[0106] Comparative Example 6

[0107] The same as Example 3, except that: the vulcanization accelerator is composed of accelerator TBSI, accelerator CBBS, and accelerator TBZTD in a mass ratio of 1.5:1.5:2.0.

[0108] Test Example 1

[0109] The apparent density, thermal conductivity, tensile strength and N-nitrosamine content of the foamed rubber-plastic materials obtained in the examples and comparative examples were measured, and the surface conditions of the products were observed. The results are shown in Table 1.

[0110] Table 1 Test results of relevant parameters of foam rubber and plastic materials

[0111]

[0112]

[0113] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A foamed rubber-plastic material free of nitrosamines, characterized in that: Including the following raw materials by mass: 7-13 parts of nitrile rubber, 5-9 parts of polyvinyl chloride, 6-10 parts of chlorinated polyethylene, 16-20 parts of chlorinated paraffin, 0.8-1.3 parts of epoxidized soybean oil, 22-26 parts of aluminum hydroxide, 10-15 parts of foaming agent, 5-8 parts of foaming aid, 1.1-1.7 parts of carbon black, 5-8 parts of organosilicon modifier, 4-5 parts of antimony trioxide, 0.5-1 parts of solid paraffin, 0.1-0.5 parts of stearic acid, 0.3-0.6 parts of polyethylene glycol, 0.2-0.5 parts of sulfur, 0.04-0.08 parts of antioxidant, 0.8-2 parts of vulcanization accelerator; The vulcanization accelerators are accelerator ZBEC and accelerator TBzTD.

2. The nitrosamine-free foamed rubber-plastic material according to claim 1, characterized in that: The foaming aid is one or more of urea, adipic acid and salicylic acid.

3. The nitrosamine-free foamed rubber-plastic material according to claim 1, characterized in that: The organosilicon modifier is one or more of γ-mercaptopropyltriethoxysilane, aminopropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

4. The nitrosamine-free foamed rubber-plastic material according to claim 1, characterized in that: The vulcanization accelerator is composed of accelerator ZBEC and accelerator TBzTD in a mass ratio of 5:

1.

5. The method for preparing the nitrosamine-free foamed rubber-plastic material according to any one of claims 1 to 4, comprising the following steps: S1, put nitrile rubber, polyvinyl chloride, chlorinated polyethylene, epoxy soybean oil, carbon black, organosilicon modifier, antimony trioxide, solid paraffin, stearic acid, polyethylene glycol, antioxidant into an internal mixer and mix, then add the first portion of aluminum hydroxide and the first portion of chlorinated paraffin and perform a first internal mixer, then add the second portion of aluminum hydroxide and the second portion of chlorinated paraffin and perform a second internal mixer, after rubber mixing is completed, discharge the rubber, slice after opening the mixing, and stack for 48 hours after cooling to obtain material No. 1; S2, adding sulfur, vulcanization accelerator, foaming agent and foaming aid to the No. 1 material, mixing evenly after refining, and then slicing to obtain No. 2 material; S3, extruding the No. 2 material in an extruder to obtain a molding rubber, and cooling the molding rubber after free foaming to obtain a foamed rubber-plastic material free of nitrosamines.

6. The preparation method according to claim 5, characterized in that: The thickness of the No. 1 material film is 8 mm, and the thickness of the No. 2 material film is 9 mm.

7. The preparation method according to claim 5, characterized in that: The extruder has a feeding section temperature of 25°C to 30°C, a plasticizing section temperature of 32°C to 35°C, a die section temperature of 35°C to 40°C, a die pressure of 0.4 to 0.5 MPa, and a rotation speed of 15 to 20 r / min.

8. The preparation method according to claim 5, characterized in that: The foaming furnace is divided into seven-zone control or six-zone control according to temperature.

9. The preparation method according to claim 8, characterized in that: The temperature of each zone of the foaming furnace is set as follows: zone one 100°C-120°C, zone two 120°C-125°C, zone three 125°C-135°C, zone four 135°C-145°C, zone five 145°C-160°C, zone six 160°C-175°C.

10. The preparation method according to claim 5, characterized in that: The initial transmission speed of the first zone of the foaming furnace is 1.1-1.3 m / min.

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