Isoprene-bromobutyl rubber composite sheet and method for producing the same

Abstract

The application discloses a kind of isoprene-brominated butyl rubber composite rubber sheet, including the laminated composite isoprene rubber layer and brominated butyl rubber layer;The main components of raw materials of isoprene rubber layer are: isoprene rubber 100 parts, stearic acid 1-4 parts, zinc oxide 2.5-6 parts, sulfur 0.3-1 part, organic vulcanization accelerator 0.13-0.4 parts, first inorganic filler 87-103 parts;The main components of raw materials of brominated butyl rubber layer are: brominated butyl rubber 100 parts, magnesium oxide 2.5-6 parts, sulfur 0.1-0.4 parts, second inorganic filler 60-85 parts;The laminated composite isoprene rubber layer and brominated butyl rubber layer are prepared by one-time vulcanization.By adjusting the components of isoprene rubber sheet and brominated butyl rubber sheet, the two rubber sheets satisfy one-time vulcanization production, the thickness of rubber sheet layer is uniform, the interface between layers is flat, which is beneficial to ensure the sealing performance of gasket.The application also discloses a production method of isoprene-brominated butyl rubber composite rubber sheet.

Description

Technical Field

[0001] This invention relates to the field of composite film production technology, specifically to an isoprene-bromobutyl rubber composite film and its production method. Background Technology

[0002] Isoprene rubber possesses excellent tear resistance, heat resistance, oxidation resistance, and oil resistance; it also exhibits good processability. Halogenated butyl rubber has low air permeability, good air tightness, thermal stability, energy absorption, ozone resistance, weathering resistance, and chemical stability, and extremely low water permeability. Composite sheets of isoprene rubber and brominated butyl rubber combine the advantages of both rubbers: the drug comes into contact with the brominated butyl rubber, ensuring the drug's safety and stability; isoprene rubber has good puncture resistance, and the sheet is not prone to leakage even after repeated punctures.

[0003] The existing methods for producing composite films include the following two:

[0004] The first method, as described in CN113103632A, involves three-stage vulcanization, which means that after the polyisoprene rubber sheet and the halogenated butyl rubber sheet are vulcanized and pre-formed separately, the polyisoprene rubber sheet and the halogenated butyl rubber sheet are aligned and bonded together in a flat vulcanization. The composite film produced by three-stage vulcanization has weaker adhesion between the two rubbers, and the production process involves more steps and a longer cycle.

[0005] The second method, as described in CN115819897A, involves two vulcanization processes. The first vulcanization is a pre-vulcanization of the brominated layer rubber sheet, while the second vulcanization involves desaturating and drying the pre-vulcanized brominated layer rubber sheet before compounding it with the polyisoprene layer rubber sheet. The vulcanization time for the pre-vulcanization needs to be precisely controlled according to the formulation. Pre-vulcanizing the brominated layer rubber sheet can fix the thickness of the brominated layer and smooth the surface, resulting in a straight interlayer interface between the two rubber layers. Therefore, the filler content requirement in the polyisoprene rubber of the two-step vulcanization is correspondingly lower. However, this formulation is not suitable for single-stage vulcanization production. To obtain a composite rubber sheet of a predetermined thickness under a predetermined vulcanization pressure, the difference between the thickness of the isoprene rubber sheet before vulcanization and the thickness of the isoprene rubber layer after vulcanization must be fully considered in the initial design of the process parameters.

[0006] Isoprene rubber is relatively soft, while brominated butyl rubber is relatively hard. The vulcanization speed, flowability, and shrinkage rate of brominated butyl rubber and isoprene rubber are inconsistent. The flowability of brominated butyl rubber is slightly worse than that of isoprene rubber, which leads to uneven sheet thickness of the two rubbers in the composite film. This, in turn, results in uneven elasticity distribution of the gasket, which adversely affects the sealing performance of the composite film. Therefore, composite films are usually not produced by single vulcanization. Summary of the Invention

[0007] One of the objectives of this invention is to overcome the defects in the prior art and provide an isoprene-bromobutyl rubber composite film. By adjusting the composition of the two rubber layers in the isoprene-bromobutyl rubber composite film, the vulcanization rates between the components are made more matched, so that the isoprene-bromobutyl rubber composite film can be prepared by one vulcanization.

[0008] To achieve the above-mentioned technical effects, the technical solution of the present invention is: an isoprene-bromobutyl rubber composite film, comprising a laminated isoprene rubber layer and a brominated butyl rubber layer;

[0009] The main components of the raw materials for the isoprene rubber layer are: 100 parts isoprene rubber, 1-4 parts stearic acid, 2.5-6 parts zinc oxide, 0.3-1 parts sulfur, 0.13-0.4 parts organic vulcanization accelerator, and 87-103 parts first inorganic filler.

[0010] The main components of the raw materials for the brominated butyl rubber layer are: 100 parts brominated butyl rubber, 2.5-6 parts magnesium oxide, 0.1-0.4 parts sulfur, and 60-90 parts of the second inorganic filler;

[0011] The composite isoprene rubber layer and brominated butyl rubber layer are obtained by a single vulcanization process.

[0012] The component optimization of the isoprene rubber layer and the brominated butyl rubber layer mainly includes the content and composition of fillers, vulcanizing agents, and vulcanization accelerators in the isoprene rubber raw material. Both the fillers and zinc oxide in the isoprene rubber layer raw material affect the flowability of the isoprene rubber during vulcanization. By comprehensively regulating the flowability of the isoprene rubber through these two components, the interface between the two rubber layers is maintained flat under a predetermined vulcanization pressure. Compared with composite sheets that undergo secondary vulcanization and have low filler content, the isoprene rubber layer with high filler content exhibits excellent thickness stability, and the thickness difference between the isoprene rubber sheet before vulcanization and the isoprene rubber layer after vulcanization is smaller.

[0013] Furthermore, the main components of the raw materials for the isoprene rubber layer are: 100 parts isoprene rubber, 2-3 parts stearic acid, 4-5 parts zinc oxide, 0.5-0.8 parts sulfur, 0.15-0.28 parts organic vulcanization accelerator, and 92-103 parts of the first inorganic filler.

[0014] And / or further, the main components of the brominated butyl rubber layer are: 100 parts brominated butyl rubber, 3-6 parts magnesium oxide, 0.2-0.3 parts sulfur, and 60-85 parts of the second inorganic filler.

[0015] The first inorganic filler includes carbon black and titanium dioxide.

[0016] A preferred technical solution is that the organic vulcanization accelerator is a combination of dimethyl disulfide carbonyl dimethylamine (TMTD) and 4,4′-dithiodimorpholine (DTDM) in a mass ratio of 1:(0.7-1.2). Specifically, the mass ratios are 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, and 1:1.2, as well as the range between the two values ​​mentioned above as the maximum and minimum values. Furthermore, taking 100 parts of isoprene rubber as a reference, the mass fraction of dimethyl disulfide carbonyl dimethylamine is 0.095-0.16 parts.

[0017] Disulfide disulfide carbonyl dimethylamine is a high-speed accelerator, while 4,4′-dithiodimorpholine has a slower vulcanization rate. The combined use of these two organic accelerators helps to improve the puncture resistance of isoprene rubber and further improve the uniformity of isoprene rubber layer thickness, avoiding warping of the rubber sheet due to differences in layer thickness, especially at the edges of the rubber sheet.

[0018] A preferred technical solution is that the main components of the first and second inorganic fillers are selected from one or more combinations of calcium carbonate, kaolin, clay, and barium sulfate. Further, the main component of both the first and second inorganic fillers is kaolin. Based on the mass of the first inorganic filler (100%), the kaolin content is 96% or more, preferably 96.7%-97.5%; based on the mass of the second inorganic filler (100%), the kaolin content is 95% or more, preferably 95.7%-96.8%.

[0019] A preferred technical solution is that the thickness ratio of the isoprene rubber layer to the brominated butyl rubber layer is 1:(0.9~1.1). Specifically, the thickness ratio of the isoprene rubber layer to the brominated butyl rubber layer is 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, and a range using the above two values ​​as the maximum and minimum values. More preferably, the thickness ratio of the isoprene rubber layer to the brominated butyl rubber layer is 1:1.

[0020] Furthermore, the thickness of the isoprene rubber layer and the brominated butyl rubber layer is 1–5 mm.

[0021] The preferred technical solution is that, taking 100 parts of isoprene rubber as a reference, the first inorganic filler includes 85-100 parts of kaolin, 0.6-1.3 parts of titanium dioxide, and 1.6-2.4 parts of carbon black;

[0022] The preferred technical solution is 100 parts of brominated butyl rubber, and the second inorganic filler includes 60-80 parts of kaolin, 1.6-2.4 parts of titanium dioxide, and 0.05-0.4 parts of carbon black.

[0023] Furthermore, the brominated butyl rubber is brominated butyl rubber 2030.

[0024] The preferred first and second inorganic fillers described above are beneficial to improving the processing performance of the corresponding rubber layers, so that the two rubber layers can achieve excellent strength and durability in the one-step vulcanization process.

[0025] The second objective of this invention is to provide a method for producing isoprene-bromobutyl rubber composite films, comprising the following steps:

[0026] S1: The raw materials for the isoprene rubber layer are processed by open milling, internal mixing, and calendering to produce isoprene sheets of a predetermined thickness;

[0027] S2: The raw materials for the brominated butyl rubber layer are processed by open milling, internal mixing, and calendering to produce brominated butyl rubber sheets of a predetermined thickness;

[0028] S3: Stack the isoprene film and the brominated butyl film together and place them in a flat vulcanizing machine for vulcanization;

[0029] The vulcanizing mold includes a first mold that contacts an isoprene film and a second mold that contacts a brominated butyl film, wherein the vulcanizing temperature of the first mold is lower than that of the second mold.

[0030] During the vulcanization process, the isoprene film is always vulcanized at the temperature of the second mold. The temperature of the isoprene film shows the following upward trend: first, it is kept at the temperature of the first mold to enter the vulcanization reaction period for pre-forming. Due to the heat transfer of the film, the temperature of the isoprene film in the later stage of the vulcanization reaction period slowly rises to the temperature of the second mold until the end of the vulcanization reaction period and the isoprene film is set.

[0031] A preferred technical solution is that the vulcanization temperature of the first mold is 157-173℃, and the vulcanization temperature of the second mold is 177-192℃. Further, the vulcanization temperature of the first mold is 160-170℃, and the vulcanization temperature of the second mold is 180-190℃. Based on the above film composition, the vulcanization mold within the preferred temperature range is beneficial for improving the adhesion between the two adhesive layers in the composite film. Based on the preferred vulcanization temperature, if the vulcanization temperature of the first mold is too high, it will cause the isoprene adhesive layer to fray, the film edges to curl, and the thickness difference of the film before and after vulcanization to increase.

[0032] The preferred technical solution is a vulcanization time of 260-320 seconds and a vulcanization pressure of 90-160 kg / cm². 2 Furthermore, the vulcanization time is 280-300 seconds, and the vulcanization pressure is 110-140 kg / cm². 2 The preferred vulcanization pressure is 115-135 kg / cm². 2 .

[0033] Excessive vulcanization time can lead to over-crosslinking and aging, especially in the isoprene adhesive layer. Vulcanization pressure is closely related to the thickness difference of the adhesive layer before and after vulcanization. Excessive vulcanization pressure will deteriorate the flatness of the interlayer interface of the composite film. Insufficient vulcanization pressure will reduce the interlayer adhesion of the composite adhesive layer, reduce the density of the film compound, and worsen the puncture resistance of the film, especially in the isoprene adhesive layer.

[0034] The preferred technical solution is that the first mold is the upper mold and the second mold is the lower mold, and in S3, the film is stacked and placed in the lower mold which is heated to the vulcanization temperature.

[0035] In the laminated rubber sheet, the brominated butyl rubber sheet first comes into contact with the lower mold and softens under heat, entering the induction period in advance. The brominated butyl rubber sheet and the isoprene rubber sheet have a heating time difference so that the flowability of the two rubber sheets tends to be consistent before vulcanization molding.

[0036] Furthermore, the thickness of the brominated butyl film is 1.5 to 2.7 mm, and the time difference between the contact between the brominated butyl film and the lower mold and the contact between the isoprene adhesive layer and the upper mold is no more than 20 seconds, preferably 5 to 10 seconds.

[0037] The advantages and beneficial effects of this invention are as follows:

[0038] This invention, an isoprene-bromobutyl rubber composite sheet, is prepared by a single vulcanization process. By adjusting the composition of the isoprene sheet and the brominated butyl sheet, the vulcanization parameters of the two different materials are more closely matched, resulting in uniform rubber sheet thickness and a straight interlayer interface. When used as a gasket, the elasticity is evenly distributed, which helps to improve the sealing performance of the gasket and effectively reduces the probability of leakage problems caused by uneven sheet thickness. Attached Figure Description

[0039] Figure 1 This is a photograph of the isoprene-bromobutyl rubber composite film from Example 1; Detailed Implementation

[0040] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0041] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating orientation or positional relationship are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] Examples and comparative examples: Components, raw materials, and equipment models:

[0043] Isoprene rubber: Fushun Yikesi;

[0044] Brominated butyl rubber: Arlanxynco 2030;

[0045] Stearic acid: Jiangyin Chaoyang Fine Chemical Co., Ltd.

[0046] Zinc oxide: Changzhou Zhiyi Zinc Industry Co., Ltd.;

[0047] Sulfur: Jiatuo Shanghai Trading Co., Ltd.;

[0048] Dimethyl disulfide carbonyl dimethylamine (TMTD): Jiangsu Aita New Materials;

[0049] 4,4′-Dithiodimorpholine (DTDM): Jiangsu Aita New Materials;

[0050] Kaolin: Lixin, Inner Mongolia, particle size 1250 mesh;

[0051] Titanium dioxide: Changzhou Tianfu New Materials Technology Co., Ltd.;

[0052] Carbon black: Shuoyuan New Materials Co., Ltd.

[0053] I. Preparation process of isoprene-bromobutyl rubber composite film sample

[0054] 1. Raw materials for preparing the isoprene adhesive layer and the brominated butyl adhesive layer;

[0055] 2. Preparation of composite film

[0056] S1: The raw materials for the isoprene rubber layer are subjected to intensive mixing (temperature 100℃, pressure 6.5kg, 9.5min) and open mixing (6.5min) to obtain isoprene compound rubber, which is then calendered to obtain 2.3mm isoprene compound rubber sheets.

[0057] S2: The raw materials for the brominated butyl rubber layer are subjected to intensive mixing (temperature 100℃, pressure 6.5kg, 10.5min) and open mixing (6.5min) to obtain isoprene compound rubber, which is then calendered to obtain 2.3mm brominated butyl compound rubber sheets.

[0058] S3: Stack the S1 and S2 rubber sheets together, with the brominated butyl compound rubber sheet located below the isoprene compound rubber sheet; heat the upper and lower molds of the flat vulcanizing machine to the vulcanization temperature, lay the stacked rubber sheets flat on the lower mold of the flat vulcanizing machine, and after a predetermined interval, close the upper and lower molds, apply a predetermined vulcanization pressure to the stacked rubber sheets, and close the mold for a predetermined vulcanization time.

[0059] S4: The composite film from S3 is cut into a die to obtain a composite film in the shape of a gasket.

[0060] S5: Cleaning, drying, testing, and packaging gaskets.

[0061] 3. Testing the flatness of the interfacial surface between the isoprene adhesive layer and the brominated butyl adhesive layer in the gasket:

[0062] Five gaskets were randomly selected from the same composite film sample, and the film was cut along the plane containing the central axis and thickness direction to obtain two identical half-gasket parts. The half-gasket parts were left to stand for 1 day to allow the film to fully recover its punching deformation.

[0063] Take five half-gaskets located at the center of the diagonal of the vulcanized rubber sheet and observe the shape of the tangent line at the interface between the two rubber layers.

[0064] 4. Test the adhesion between the isoprene adhesive layer and the brominated butyl adhesive layer in the gasket according to the peel strength test method in YBB00102003-2015 of the National Pharmaceutical Packaging Material Standard.

[0065] 5. Conformity testing of the gaskets in the example.

[0066] II. Examples and Comparative Examples Regarding the Composition of Organic Vulcanization Accelerators in Composite Film Raw Materials

[0067] Raw materials for the isoprene adhesive layer and the brominated butyl adhesive layer in Example 1:

[0068] Isoprene adhesive layer: 100 parts isoprene rubber, 2.5 parts stearic acid, 4.5 parts zinc oxide, 0.6 parts sulfur, 0.1 parts TMTD, 0.1 parts DTDM, 100 parts kaolin, 1 part titanium dioxide, and 2 parts carbon black;

[0069] Brominated butyl rubber layer: 100 parts brominated butyl rubber, 0.25 parts sulfur, 4.5 parts magnesium oxide, 70 parts kaolin, 2.5 parts titanium dioxide, and 0.15 parts carbon black.

[0070] Vulcanization process parameters: Upper mold vulcanization temperature 165℃, lower mold vulcanization temperature 185℃; S3 interval time is 10s, vulcanization pressure is 125kg / cm². 2 The vulcanization time is 290 seconds.

[0071] Raw materials for the isoprene adhesive layer and the brominated butyl adhesive layer in Example 2:

[0072] Isoprene adhesive layer: 100 parts isoprene rubber, 2.5 parts stearic acid, 4.5 parts zinc oxide, 0.6 parts sulfur, 0.15 parts TMTD, 0.18 parts DTDM, 100 parts kaolin, 1 part titanium dioxide, and 2 parts carbon black;

[0073] Brominated butyl rubber layer: 100 parts brominated butyl rubber, 0.25 parts sulfur, 4.5 parts magnesium oxide, 70 parts kaolin, 2.5 parts titanium dioxide, and 0.15 parts carbon black.

[0074] The vulcanization process parameters for Example 2 are the same as those for Example 1.

[0075] Raw materials for the isoprene adhesive layer and the brominated butyl adhesive layer in Comparative Example 1:

[0076] Isoprene adhesive layer: 100 parts isoprene rubber, 2.5 parts stearic acid, 4.5 parts zinc oxide, 0.6 parts sulfur, 0.3 parts TMTD, 0.2 parts DTDM, 100 parts kaolin, 1 part titanium dioxide, and 2 parts carbon black;

[0077] Brominated butyl rubber layer: 100 parts brominated butyl rubber, 0.25 parts sulfur, 4.5 parts magnesium oxide, 70 parts kaolin, 2.5 parts titanium dioxide, and 0.15 parts carbon black.

[0078] Vulcanization process parameters: Upper mold vulcanization temperature 165℃, lower mold vulcanization temperature 185℃; S3 interval time is 10s, vulcanization pressure is 125kg / cm². 2 The vulcanization time is 260 seconds.

[0079] Raw materials for the isoprene adhesive layer and the brominated butyl adhesive layer in Example 3:

[0080] Isoprene adhesive layer: 100 parts isoprene rubber, 2.5 parts stearic acid, 4.5 parts zinc oxide, 0.6 parts sulfur, 0.085 parts TMTD, 0.115 parts DTDM, 100 parts kaolin, 1 part titanium dioxide, and 2 parts carbon black;

[0081] Brominated butyl rubber layer: 100 parts brominated butyl rubber, 0.25 parts sulfur, 4.5 parts magnesium oxide, 70 parts kaolin, 2.5 parts titanium dioxide, and 0.15 parts carbon black.

[0082] The vulcanization process parameters for Example 3 are the same as those for Example 1.

[0083] Example 4: Raw materials for the isoprene adhesive layer and the brominated butyl adhesive layer:

[0084] Isoprene adhesive layer: 100 parts isoprene rubber, 2.5 parts stearic acid, 4.5 parts zinc oxide, 0.6 parts sulfur, 0.125 parts TMTD, 0.075 parts DTDM, 100 parts kaolin, 1 part titanium dioxide, and 2 parts carbon black;

[0085] Brominated butyl rubber layer: 100 parts brominated butyl rubber, 0.25 parts sulfur, 4.5 parts magnesium oxide, 70 parts kaolin, 2.5 parts titanium dioxide, and 0.15 parts carbon black.

[0086] The vulcanization process parameters for Example 4 are the same as those for Example 1.

[0087] The isoprene adhesive layer and brominated butyl adhesive layer in the gasket showed obvious signs of wear. The visual inspection results of the interlayer interface are shown in the table below:

[0088]

[0089] Compared with three-stage and two-stage vulcanization, the matching degree of vulcanization rate between the isoprene rubber layer and the brominated butyl rubber layer in the single-stage vulcanization process has a more significant impact, especially on the straightness of the cut edge of the half-gasket interface and the thickness of the gasket.

[0090] The interface edges of Examples 3 and 4 are relatively smooth and wavy. The difference is that the isoprene rubber layer in the gasket of Example 3 is slightly thinner, and there is a small amount of isoprene rubber overflowing from the periphery of the composite film fed from the flat vulcanizing agent. In Example 4, the brominated butyl rubber layer protrudes more towards the isoprene rubber layer. In Comparative Example 1, the isoprene rubber layer protrudes more towards the brominated butyl rubber layer. This shows that, based on the predetermined rubber layer raw material formula, the sum of the contents of vulcanizing accelerators TMTD and DTDM in the isoprene rubber layer raw material and the ratio of the two vulcanizing accelerators will significantly affect the vulcanization speed of the isoprene rubber layer and the degree of matching with the vulcanization speed of the brominated butyl rubber layer.

[0091] In Example 3, the thickness of the isoprene rubber layer in the gasket sample was slightly reduced, the leakage detection pass rate decreased, and the overall elasticity of the gasket was worse than that in Example 1, indicating that the thickness of the isoprene rubber layer has a significant impact on the leakage detection pass rate.

[0092] In Comparative Example 1, the vulcanization accelerator content in the isoprene rubber layer raw material was too high, resulting in an excessively fast vulcanization rate of the isoprene rubber layer. This caused the isoprene rubber layer to be squeezed towards the brominated butyl rubber layer, forming a corrugated interface edge.

[0093] III. Comparative Examples of Fillers in Isoprene Rubber Raw Materials

[0094] Raw materials for the isoprene adhesive layer and the brominated butyl adhesive layer in Comparative Example 2:

[0095] Isoprene adhesive layer: 100 parts isoprene rubber, 2.5 parts stearic acid, 4.5 parts zinc oxide, 0.6 parts sulfur, 0.1 parts TMTD, 0.1 parts DTDM, 75 parts kaolin, 1 part titanium dioxide, and 2 parts carbon black;

[0096] Brominated butyl rubber layer: 100 parts brominated butyl rubber, 0.25 parts sulfur, 4.5 parts magnesium oxide, 70 parts kaolin, 2.5 parts titanium dioxide, and 0.15 parts carbon black.

[0097] The vulcanization process parameters for Comparative Example 2 are the same as those for Example 1.

[0098] The results of the interfacial flatness test between the isoprene adhesive layer and the brominated butyl adhesive layer in the gasket are shown in the table below:

[0099]

[0100] Compared with Example 1, the kaolin content of the isoprene rubber layer raw material in Comparative Example 2 was reduced, and there was more isoprene rubber overflowing around the perimeter of the vulcanized composite sheet. The isoprene rubber layer in the gasket was significantly thinner. This indicates that the fluidity of the isoprene rubber increased during the vulcanization process, which is not conducive to maintaining the overall elasticity and resistance to repeated punctures of the gasket.

[0101] IV. Examples and Comparative Examples of Vulcanization Process Conditions

[0102] The raw materials for the isoprene rubber layer and the brominated butyl rubber layer in Example 5 are the same as those in Example 1. The vulcanization process parameters are: vulcanization temperature of the upper mold 170°C, vulcanization temperature of the lower mold 185°C; S3 interval time is 10s, vulcanization pressure is 125kg / cm2, and vulcanization time is 290s.

[0103] The raw materials for the isoprene rubber layer and the brominated butyl rubber layer in Example 6 are the same as those in Example 1. The vulcanization process parameters are: vulcanization temperature of the upper mold 165℃, vulcanization temperature of the lower mold 185℃; S3 interval time is 10s, vulcanization pressure is 115kg / cm2, and vulcanization time is 290s.

[0104] The raw materials for the isoprene rubber layer and brominated butyl rubber layer in Example 7 are the same as those in Example 1. The vulcanization process parameters are: vulcanization temperature of the upper mold 165°C, vulcanization temperature of the lower mold 180°C; S3 interval time is 8s, and vulcanization pressure is 125kg / cm². 2 The vulcanization time is 290 seconds.

[0105] The raw materials for the isoprene rubber layer and the brominated butyl rubber layer in Example 8 are the same as those in Example 1. The vulcanization process parameters are: vulcanization temperature of the upper mold 175°C, vulcanization temperature of the lower mold 185°C; S3 interval time is 20s, vulcanization pressure is 125kg / cm2, and vulcanization time is 290s.

[0106] The raw materials for the isoprene rubber layer and the brominated butyl rubber layer in Comparative Example 3 were the same as those in Example 1. The vulcanization process parameters were: vulcanization temperature of the upper mold 185°C, vulcanization temperature of the lower mold 185°C; S3 interval time of 10s, vulcanization pressure of 125kg / cm2, and vulcanization time of 290s.

[0107] The raw materials for the isoprene rubber layer and brominated butyl rubber layer in Comparative Example 4 were the same as those in Example 1. The vulcanization process parameters were: upper mold vulcanization temperature 165°C, lower mold vulcanization temperature 175°C; S3 interval time 10s, vulcanization pressure 125kg / cm². 2 The vulcanization time is 290 seconds.

[0108]

[0109] The data from Examples 1 and 6 show that excessively low vulcanization pressure can lead to a decrease in the straightness of the cut edges and the uniformity of the adhesive layer thickness, as well as a slight decrease in the gasket leakage detection pass rate.

[0110] The data from Examples 1 and 8 show that if the laminated film is placed on the flat vulcanizing machine for too long, the temperature of the lower mold of the film in the flat vulcanizing machine is transferred to the isoprene film through the brominated butyl film. The temperature of the isoprene film is too high before the vulcanizing mold is closed, and the laminated film shrinks at the same time. The interlayer interface of the gasket obtained by vulcanization has greater undulation than the wavy edge. Although the adhesion between the layers increases, the elasticity difference at different positions of the gasket leads to a low leakage detection pass rate.

[0111] The data from Examples 1, 3, and 4 show that the excessively high upper mold temperature in Example 3 and the excessively low lower mold temperature in Example 4 both resulted in a faster vulcanization rate for the isoprene rubber layer compared to the brominated butyl rubber layer. During the vulcanization and molding of the isoprene rubber layer, the brominated butyl rubber layer protruded more towards the brominated butyl rubber layer. Given the same vulcanization time, the incomplete vulcanization of the brominated butyl rubber layer in Example 4 was the main reason for the significant decrease in adhesion between the rubber layers.

[0112] V. The gasket conformity test results of the embodiment are shown in the table below:

[0113] Tested according to the enterprise standard "Polyisoprene Rubber / Brominated Butyl Rubber Gaskets for Pen-type Syringe Cartridge Bottles" Q / 320281YDZ32-2022:

[0114]

[0115]

[0116] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A production method of isoprene-brominated butyl rubber composite sheet, characterized in that, the isoprene-brominated butyl rubber composite sheet comprises laminated isoprene rubber layer and brominated butyl rubber layer; the raw material of the isoprene rubber layer mainly comprises: isoprene rubber 100 parts, stearic acid 1-4 parts, zinc oxide 2.5-6 parts, sulfur 0.3-1 part, organic vulcanization accelerator 0.13-0.4 parts, and first inorganic filler 87-103 parts; the raw material of the brominated butyl rubber layer mainly comprises: brominated butyl rubber 100 parts, magnesium oxide 2.5-6 parts, sulfur 0.1-0.4 parts, and second inorganic filler 60-90 parts; the laminated isoprene rubber layer and brominated butyl rubber layer are prepared by one-time vulcanization; the thickness ratio of the isoprene rubber layer and the brominated butyl rubber layer is 1:(0.9-1.1) the production method comprises the following steps: S1: preparing isoprene rubber sheet with a predetermined thickness by opening, mixing, and calendering the raw material of the isoprene rubber layer; S2: preparing brominated butyl rubber sheet with a predetermined thickness by opening, mixing, and calendering the raw material of the brominated butyl rubber layer; S3: laminating the isoprene rubber sheet and the brominated butyl rubber sheet, and placing them in a flat vulcanization machine for vulcanization; The vulcanization mold includes a first mold abutting with the isoprene rubber sheet and a second mold abutting with the brominated butyl rubber sheet, the vulcanization temperature of the first mold is lower than that of the second mold; the vulcanization temperature of the first mold is 157-173℃, and the vulcanization temperature of the second mold is 177-192℃; the vulcanization time is 280-300s, and the vulcanization pressure is 110-140kg / cm 2 .

2. The production method of isoprene-brominated butyl rubber compound sheet according to claim 1, characterized by, the organic vulcanization accelerator is a combination of dithio-bis-sulfonamide dimethylamine and 4,4'-dithio-bis-morpholine, and the mass ratio is 1:(0.7-1.2).

3. The production method of isoprene-brominated butyl rubber compound sheet according to claim 1, characterized by, The first inorganic filler and the second inorganic filler are selected from one or a combination of more than two of calcium carbonate, kaolin, clay, and barium sulfate.

4. The production method of isoprene-brominated butyl rubber compound sheet according to claim 1, characterized by, Taking 100 parts of isoprene rubber as a reference, the first inorganic filler comprises kaolin 85-100 parts, titanium white 0.6-1.3 parts, and carbon black 1.6-2.4 parts.

5. The production method of isoprene-brominated butyl rubber compound sheet according to claim 1, characterized by, Taking 100 parts of brominated butyl rubber as a reference, the second inorganic filler comprises kaolin 60-80 parts, titanium white 1.6-2.4 parts, and carbon black 0.05-0.4 parts.

6. The production method of isoprene-brominated butyl rubber compound sheet according to claim 1, characterized by, The first mold is an upper mold, and the second mold is a lower mold, and the laminated sheet is placed in the lower mold which is heated to a vulcanization temperature in S3.

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