A combined mold for preparing silica gel tube and a preparation method thereof

Abstract

The present application relates to the technical field of silica gel tube preparation, and discloses a combined mold and preparation method for silica gel tube preparation, wherein the combined mold comprises a product vulcanization mold and a soft core vulcanization mold; the soft core vulcanization mold is used for forming a soft core with a hollow structure for preparing a silica gel tube; the product vulcanization mold comprises a product upper mold, a product lower mold and a product mold cavity formed between the product upper mold and the product lower mold; the soft core is assembled at both ends through a gas inlet end snap ring and a terminal snap ring, and then placed in the product mold cavity to form a silica gel tube. The combined mold has a simple structure and is convenient to prepare; the soft core with a hollow structure is vulcanized and formed in the mold, the vulcanization efficiency is high, and the mold is convenient to demold; the process of preparing the silica gel tube by using the combined mold is more conducive to preparing a silica gel tube with a multi-layer wrapping structure, meets the pressure requirement of the vehicle silica gel tube, and the wall thickness is uniform and controllable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone tube preparation, and particularly relates to a combined mold for silicone tube preparation and a preparation method. BACKGROUND

[0002] At present, turbochargers are widely used in the automobile industry, and a rubber hose is connected between the turbocharger and an intercooler. Intake gas pressurized by a fan of the turbocharger flows through the rubber hose. Because the fan is driven by exhaust gas of an engine, the intake gas becomes very high in temperature. The rubber hose must have heat resistance and vibration durability at high temperature, and therefore, silicone rubber is mainly used as a material of the rubber hose capable of withstanding high temperature.

[0003] There are two production processes for silicone tubes, one is an extrusion process, and the other is a cloth clamping process. The extrusion process cannot realize a multi-layer cloth wrapping structure, and it is difficult to meet the pressure requirement of the silicone tube for vehicles, and is mainly used in cooling systems. The cloth clamping process is a relatively widely used form for the production of the silicone tube for vehicles. The manufacturing process is simple, but the unique cloth clamping structure has defects in ensuring the wall thickness at the lap joint position of the hose, and the silicone tube vulcanization process is carried out in an oven or a vulcanization tank, and the vulcanization parameters are 180 DEG C x 1 hour, and the efficiency is low.

[0004] Chinese patent with publication number CN102642291B discloses a preparation process of a large-diameter silicone tube, including the following preparation steps: (a) feeding and mixing: 95% to 98.2% of silicone rubber, 1% to 4.8% of vulcanizing agent, and 0.2% to 0.8% of color master batch are put into a feeding device to be mixed to obtain a mixture; (b) extrusion and inflation: the mixed mixture is extruded into a large-diameter silicone tube preliminary product through an extrusion die of an extrusion molding machine, and gas is continuously filled into a cavity of the large-diameter silicone tube preliminary product; (c) vulcanization molding: the large-diameter silicone tube preliminary product is vulcanized through a vulcanization machine to obtain a large-diameter silicone tube product. The preparation process is an extrusion process, the vulcanization temperature is high, the vulcanization time is long, the vulcanization efficiency is low, and the energy consumption is large. SUMMARY

[0005] In order to solve the technical problems of high vulcanization temperature, long vulcanization time and low efficiency of the silicone tube mold in the process of preparing the silicone tube, the present application provides a combined mold for silicone tube preparation and a preparation method, a soft core is used for vulcanization molding in the mold, the vulcanization temperature is low and the vulcanization time is short, the vulcanization efficiency is high, the wall thickness can be well controlled, and the pressure requirement of the silicone tube for vehicles can be met.

[0006] The specific technical scheme of the present application is as follows:

[0007] In a first aspect, the present application provides a combined mold for preparing a silicone tube, which comprises a product vulcanization mold and a soft core vulcanization mold; the soft core vulcanization mold is used to form a soft core with a hollow structure for preparing a silicone tube; the product vulcanization mold comprises a product upper mold, a product lower mold, and a product mold cavity formed between the product upper mold and the product lower mold; the soft core is assembled at both ends of the soft core by a gas inlet end clamp and an end clamp, and then placed in the product mold cavity to form a silicone tube.

[0008] The traditional molding process uses a hard core to prepare a silicone tube, which results in long vulcanization time and low vulcanization efficiency. The present application uses a combined mold to prepare a silicone tube by a molding process, which comprises two sets of molds, i.e., a product vulcanization mold and a soft core vulcanization mold. The soft core vulcanization mold is used to prepare a soft core, which uses a traditional molding process and can be reused. The soft core is used to replace the hard core for preparing a silicone tube. After being assembled at both ends of the soft core by a gas inlet end clamp and an end clamp, the soft core is placed in a mold cavity for sealing. Through the control of the vulcanization process, the vulcanization temperature can be reduced and the vulcanization time can be shortened, thereby achieving the purpose of improving the vulcanization effect. The use of a soft core also facilitates demolding. Thus, the combined mold is simple to prepare, the soft core can be reused, and the cost and energy consumption are low. The prepared silicone tube can meet the pressure requirements of a vehicle silicone tube.

[0009] Preferably, the soft core vulcanization mold comprises a soft core upper mold, a soft core lower mold, and a soft core mold cavity formed between the soft core upper mold and the soft core lower mold; a solid hard core is placed in the soft core mold cavity to form a hollow structure of the soft core.

[0010] The main structures of the soft core vulcanization mold and the product vulcanization mold are consistent, and the difference lies in that the product vulcanization mold further comprises notches matched with the gas inlet end clamp and the end clamp.

[0011] Preferably, a gas passage is provided in the middle axis of the gas inlet end clamp; the gas passage is used for introducing nitrogen; and the end clamp is provided in a sealed manner.

[0012] The introduction of nitrogen into the hollow structure of the soft core is beneficial to heat transfer during the vulcanization process and improves the vulcanization efficiency. The clamps are beneficial to the sealing air tightness and facilitate demolding.

[0013] In a second aspect, the present application further provides a method for preparing a multi-layer wrapped structure silicone tube using the above combined mold, which comprises the following steps:

[0014] (1) raw materials of a soft core are formed and vulcanized in a soft core vulcanization mold to form a soft core with a hollow structure, and the soft core is assembled at both ends by a gas inlet end clamp and an end clamp;

[0015] (2) raw materials of a silicone tube are mixed, calendered, and cut, and then wrapped on the inner core for shaping, and the process is repeated multiple times to form a multi-layer wrapped structure, and finally an unfinished product is obtained;

[0016] (3) Put the unfinished product into the product vulcanization mold, clamp and vulcanize, pass nitrogen through the gas inlet end snap ring during vulcanization, and after vulcanization is completed, demold and demold the inner core to obtain the silica gel tube.

[0017] Compared with the traditional extrusion process, cloth clamping process and mold pressing process, the process for preparing the silica gel tube by using the combined mold in the application is more conducive to preparing the silica gel tube with a multi-layer cloth wrapping structure, meets the pressure requirement of the vehicle silica gel tube, and the wall thickness is uniform and controllable. Moreover, the soft core with a hollow structure has high heat transfer efficiency, short vulcanization time, low energy consumption for preparing the silica gel tube, and is reusable, easy to demold. In addition, the soft core can be prepared into various shapes according to the requirements of the product silica gel tube.

[0018] As preferred, in step (1), the raw material of the soft core includes butyl rubber; the hardness of the soft core is 70-80 SHA, and the thickness is 8-10 mm; the vulcanization temperature is 150±5℃, and the time is 3-6 h.

[0019] The soft core adopts butyl rubber, which has better air tightness, and can avoid the influence of poor air tightness on the quality of the product silica gel tube when nitrogen is passed into the soft core. Moreover, the hardness and thickness of the soft core need to be strictly controlled. Under the hardness and thickness, the support for the silica gel tube forming can be ensured, and the nitrogen heat transfer efficiency is high, and the vulcanization time is reduced.

[0020] As preferred, in step (2), the raw material of the silica gel tube includes 100 parts of silicone rubber, 1-2 parts of vulcanizing agent, 0.5-1 part of color masterbatch, and 0.8-1.5 parts of anti-frost agent by weight.

[0021] The raw material formula components of the silica gel tube also affect the formability of the multi-layer cloth wrapping structure and the vulcanization process parameters.

[0022] As preferred, in step (2), the mixing temperature is ≤30℃, and the time is 8-10 min.

[0023] As preferred, in step (2), the number of layers of the multi-layer cloth wrapping structure is not less than 3 layers; the thickness of the multi-layer cloth wrapping structure is consistent with the wall thickness of the silica gel tube, and the type of the raw material of each layer of the silica gel tube is selected according to the performance requirements of the silica gel tube.

[0024] The number of layers of the multi-layer cloth wrapping structure can ensure to meet the pressure requirement of the vehicle silica gel tube.

[0025] As preferred, in step (3), the clamping pressure is 10±1 MPa; the vulcanization temperature is 150±5℃, and the time is 25±5 min; the nitrogen pressure is 1±0.1 MPa; and the volume of the silica gel tube is not greater than the remaining volume after the inner core is placed in the product mold cavity.

[0026] Under the influence of the above preparation process, the vulcanization process conditions of the temperature of 150±5℃ and the time of 25±5min can not only meet the pressure requirement of the vehicle silica gel tube, but also reduce the energy consumption. Thus, the parameter conditions are related and influenced each other, and the best effect is achieved.

[0027] Compared with the prior art, the beneficial effects of the present application are:

[0028] (1) The combined mold has simple structure and is convenient to prepare, the soft core in the hollow structure is vulcanized and formed in the mold, the vulcanization efficiency is high, and the mold is convenient to demold;

[0029] (2) The material, hardness and thickness of the soft core need to be strictly controlled, under the hardness and thickness, the supportability for the silica gel tube forming can be ensured, and the nitrogen heat transfer efficiency is high, and the vulcanization time is reduced;

[0030] (3) The process of preparing the silica gel tube by using the combined mold is more conducive to preparing the silica gel tube with a multi-layer cloth structure, meets the pressure requirement of the vehicle silica gel tube, the wall thickness is uniform and controllable, and the parameter conditions are related and influenced each other, and the best effect is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structure schematic view of the product vulcanization mold or the soft core vulcanization mold in the present application;

[0032] Figure 2 is a structure schematic view of the lower mold (left) and the upper mold (right) of the product in the present application;

[0033] Figure 3 is a cross-sectional schematic view of the lower mold (left) and the soft core lower mold (right) of the product in the present application;

[0034] Figure 4 is a structure schematic view of the silica gel tube in the present application;

[0035] Figure 5 is an assembly schematic view of the gas inlet end snap ring and the end snap ring of the soft core in the present application.

[0036] The figure marks are: product vulcanization mold 1, product lower mold 101, product upper mold 102, product mold cavity 103, gas inlet end snap ring 104, end snap ring 105, soft core 2, soft core lower mold 201, soft core mold cavity 202, silica gel tube 3. DETAILED DESCRIPTION

[0037] The present application will be further described below in combination with examples.

[0038] General example

[0039] A combined mold for silicone tube preparation includes a product vulcanization mold 1 and a soft core vulcanization mold, and the product vulcanization mold 1 has the same main structure as the soft core vulcanization mold. The soft core vulcanization mold includes a soft core upper mold, a soft core lower mold 201, and a soft core cavity 202 formed between the soft core upper mold and the soft core lower mold 201, and a solid hard core is placed in the soft core cavity 202 when the soft core 2 is formed to form a hollow structure. The product vulcanization mold 1 includes a product upper mold 102, a product lower mold 101, and a product cavity 103 formed between the product upper mold 102 and the product lower mold 101, and the soft core 2 is placed in the product cavity 103 after being assembled at both ends of the soft core 2 by a gas inlet end clasp 104 and a terminal clasp 105, and there are notches on the product upper mold 102 and the product lower mold 101 that are in sealing cooperation with the gas inlet end clasp 104 and the terminal clasp 105. After assembly is completed, the product vulcanization mold 1 is in a sealed state, the middle axis of the gas inlet end clasp 104 is provided with a gas passage for introducing nitrogen, and the terminal clasp 105 is in a sealed state.

[0040] The above combined mold is used for preparing a multi-layer wrapped structure silicone tube, and the method includes the following steps:

[0041] (1) The raw material (butyl rubber) of the soft core is formed in the soft core vulcanization mold, and vulcanized under the condition of a temperature of 150±5℃ and a time of 3-6h to form a soft core with a hollow structure, the hardness of the soft core is 70-80SHA, and the thickness is 8-10mm, and the soft core is assembled at both ends by a gas inlet end clasp and a terminal clasp;

[0042] (2) The raw material (including 100 parts of silicone rubber, 1-2 parts of vulcanizing agent, 0.5-1 part of color master, and 0.8-1.5 parts of frost-proof agent by weight) of the silicone tube is mixed under the condition of a temperature of ≤30℃ and a time of 8-10min, then calendered, and then wrapped on the inner core to be shaped, and repeated multiple times to form a multi-layer wrapped structure, the number of layers of the multi-layer wrapped structure is not less than 3, the thickness of the multi-layer wrapped structure is consistent with the wall thickness of the to-be-formed silicone tube, and the type of the raw material of each layer of the silicone tube is selected according to the performance requirement of the to-be-formed silicone tube, the volume of the to-be-formed silicone tube is not greater than the remaining volume after the inner core is placed in the product cavity, and finally an unfinished product is obtained;

[0043] (3) The unfinished product is placed in the product vulcanization mold, the mold is closed under a pressure of 10±1MPa, and then vulcanized under the condition of a temperature of 150±5℃ and a time of 25±5min, nitrogen is introduced through the gas inlet end clasp during vulcanization, the pressure of the nitrogen is 1±0.1MPa, and after vulcanization is completed, demolding and inner core removal are performed to obtain a silicone tube.

[0044] Example 1

[0045] As Figure 1As shown, a combined mold for silicone tube preparation includes a product vulcanization mold 1 and a soft core vulcanization mold, and the product vulcanization mold 1 has the same main structure as the soft core vulcanization mold. The soft core vulcanization mold includes a soft core upper mold, a soft core lower mold 201, and a soft core cavity 202 formed between the soft core upper mold and the soft core lower mold 201. When the soft core 2 is formed, a solid hard core is placed in the soft core cavity 202 to form a hollow structure. As shown, Figure 2 As shown, the product vulcanization mold 1 includes a product upper mold 102, a product lower mold 101, and a product cavity 103 formed between the product upper mold 102 and the product lower mold 101. As shown, Figure 5 As shown, after the soft core 2 is assembled at both ends by the gas inlet end snap ring 104 and the end snap ring 105, it is placed in the product cavity 103. As shown, Figure 3 As shown, there are notches on the product upper mold 102 and the product lower mold 101 that seal with the gas inlet end snap ring 104 and the end snap ring 105. After assembly, the product vulcanization mold 1 is in a sealed state. The middle axis of the gas inlet end snap ring 104 is provided with a gas passage for the introduction of nitrogen, and the end snap ring 105 is sealed. After the molding and vulcanization process, as shown, Figure 4 As shown, a silicone tube is obtained.

[0046] The method for preparing a multi-layer wrapped structure silicone tube using the above combined mold includes the following steps:

[0047] (1) Take the raw material of the soft core (including 100 parts of butyl rubber, 1 part of vulcanizing agent DBPMH 101-45S, 0.6 parts of color master RAL 2002, and 1.1 parts of frost inhibitor F-10 by weight) and form it in the soft core vulcanization mold. Vulcanize at a temperature of 150°C for 5h to form a soft core with a hollow structure. The hardness of the soft core is 70SHA, and the thickness is 8mm. The soft core is assembled at both ends by the gas inlet end snap ring and the end snap ring.

[0048] (2) Take the raw material of the silicone tube (including 100 parts of silicone rubber R401 / 70, 1 part of vulcanizing agent DBPMH 101-45S, 0.6 parts of color master RAL 2002, and 1.1 parts of frost inhibitor F-10 by weight) and mix it at a temperature of 30°C for 8min. Then, it is calendered, wrapped on the inner core, and shaped. Then, it is repeated twice to form a three-layer wrapped structure, and finally, an unfinished product is obtained.

[0049] (3) Put the unfinished product into the product vulcanization mold and close the mold under a pressure of 10MPa. Then, vulcanize at a temperature of 150°C for 25min. During vulcanization, nitrogen is introduced through the gas inlet end snap ring, and the pressure of the nitrogen is 1MPa. After vulcanization, demold and remove the inner core to obtain a silicone tube.

[0050] Example 2

[0051] The difference from Example 1 is that

[0052] The method for preparing the multi-layer wrapped structure silica gel tube using the combined mold comprises the following steps:

[0053] (1) The raw material of the soft core (including 100 parts of butyl rubber, 1.1 parts of vulcanizing agent DBPMH 101-45S, 0.6 parts of color master RAL 2002, and 1.1 parts of frost inhibitor F-10 by weight) is formed in a soft core vulcanizing mold, vulcanized at a temperature of 150°C for 6h, and a soft core with a hollow structure is formed. The hardness of the soft core is 75SHA, and the thickness is 10mm. The soft core is assembled at both ends through the gas inlet end clasp and the end clasp;

[0054] (2) The raw material of the silica gel tube (including 100 parts of silicone rubber R401 / 70, 1 part of vulcanizing agent DBPMH 101-45S, 0.6 parts of color master RAL 2002, and 1.1 parts of frost inhibitor F-10 by weight) is mixed at a temperature of 30°C for 8min, then calendered, then wrapped on the inner core for shaping, and then repeated twice to form a three-layer wrapped structure, and finally an unfinished product is obtained;

[0055] (3) The unfinished product is placed in a product vulcanizing mold, and the mold is closed under a pressure of 10MPa, and then vulcanized at a temperature of 150°C for 30min. Nitrogen gas is introduced through the gas inlet end clasp during vulcanization, and the pressure of the nitrogen gas is 1MPa. After vulcanization, the mold is removed and the inner core is removed, and a silica gel tube is obtained.

[0056] Example 3

[0057] The difference from Example 1 is that:

[0058] The method for preparing the multi-layer wrapped structure silica gel tube using the combined mold comprises the following steps:

[0059] (1) The raw material of the soft core (including 100 parts of butyl rubber, 1 part of vulcanizing agent DBPMH 101-45S, 0.6 parts of color master RAL 2002, and 1.1 parts of frost inhibitor F-10 by weight) is formed in a soft core vulcanizing mold, vulcanized at a temperature of 150°C for 5h, and a soft core with a hollow structure is formed. The hardness of the soft core is 70SHA, and the thickness is 8mm. The soft core is assembled at both ends through the gas inlet end clasp and the end clasp;

[0060] (2) Take the raw material of the silica gel tube (by weight, including 100 parts of silicone rubber R401 / 70, 1.5 parts of vulcanizing agent DBPMH101-45S, 0.7 parts of color master RAL 2002, 1.2 parts of frost inhibitor F-10) under the conditions of temperature 30℃ and time 10min, then calendering, then coating on the inner core for shaping, then repeating 2 times to form a three-layer wrapping structure, and finally obtaining an unfinished product;

[0061] (3) Put the unfinished product into the product vulcanization mold under the pressure of 11MPa, and vulcanize under the condition of temperature 155℃ for 25min. Nitrogen is introduced through the gas inlet end ring during vulcanization, and the pressure of nitrogen is 1.1MPa. After vulcanization, demolding and inner core removal are performed, and the silica gel tube is obtained.

[0062] Example 4

[0063] The difference from Example 1 is that:

[0064] The preparation method of the silica gel tube comprises the following steps:

[0065] (1) Take the raw material of the soft core (by weight, including 100 parts of butyl rubber, 1.5 parts of vulcanizing agent DBPMH101-45S, 0.5 parts of color master RAL 2002, 1.2 parts of frost inhibitor F-10) in the soft core vulcanization mold, vulcanize under the condition of temperature 155℃ for 5h, form a soft core with hollow structure, the hardness of the soft core is 70SHA, and the thickness is 10mm. The soft core is assembled through the gas inlet end ring and the end ring at both ends of the soft core;

[0066] (2) Take the raw material of the silica gel tube (by weight, including 100 parts of silicone rubber R401 / 70, 1.5 parts of vulcanizing agent DBPMH101-45S, 0.5 parts of color master RAL 2002, 1.2 parts of frost inhibitor F-10) under the conditions of temperature 25℃ and time 10min, then calendering, then coating on the inner core for shaping, then repeating 2 times to form a three-layer wrapping structure, and finally obtaining an unfinished product;

[0067] (3) Put the unfinished product into the product vulcanization mold under the pressure of 10MPa, and vulcanize under the condition of temperature 155℃ for 25min. Nitrogen is introduced through the gas inlet end ring during vulcanization, and the pressure of nitrogen is 1.1MPa. After vulcanization, demolding and inner core removal are performed, and the silica gel tube is obtained.

[0068] The combined mold has simple structure and is convenient to prepare, the explosion pressure of the silica gel pipe obtained by the above embodiment is greater than or equal to 1 MPa, the adhesive strength is greater than or equal to 2.0 N / mm, the pressure requirement of the vehicle silica gel pipe can be met, the vulcanization time is short, and the vulcanization efficiency is high. The material, hardness and thickness of the soft core need to be strictly controlled, under the hardness and thickness, the supportability for the silica gel pipe forming can be ensured, and the nitrogen heat transfer efficiency is relatively high, the vulcanization time is reduced, and the performance of the silica gel pipe prepared outside the process parameter condition range of the application is reduced, and the best effect cannot be achieved.

[0069] The raw materials and equipment used in the application are common raw materials and equipment in the field, unless otherwise specified; the method used in the application is a conventional method in the field, unless otherwise specified.

[0070] The above is only a preferred embodiment of the application, and does not limit the application, any simple modification, change and equivalent transformation of the above embodiment according to the technical essence of the application still belong to the protection scope of the technical solution of the application.

Claims

1. A method for preparing a multi-layered fabric-coated silicone tube, characterized in that, Includes the following steps: (1) The raw material of the soft core includes butyl rubber. The raw material is molded and vulcanized in the soft core vulcanization mold to form a soft core with a hollow structure. The hardness of the soft core is 70~80SHA and the thickness is 8~10mm. The soft core is assembled at both ends of the soft core through the air inlet end retaining ring and the end retaining ring. (2) Take the raw material of silicone tube, mix, calender and cut it, then wrap it on the inner core for shaping, repeat the process many times to form a multi-layered fabric structure, and finally obtain the unfinished product; (3) Place the unfinished product into the product vulcanization mold, close the mold and vulcanize. During vulcanization, nitrogen gas is introduced through the gas inlet end retainer. The vulcanization temperature is 150±5℃, the time is 25±5min, and the nitrogen pressure is 1±0.1MPa. After vulcanization, demold and remove the inner core to obtain the silicone tube.

2. The preparation method according to claim 1, characterized in that, In step (1), the vulcanization temperature is 150±5℃ and the time is 3~6h.

3. The preparation method according to claim 1, characterized in that, In step (2), by weight, the raw materials of the silicone tube include 100 parts of silicone rubber, 1 to 2 parts of vulcanizing agent, 0.5 to 1 part of color masterbatch, and 0.8 to 1.5 parts of anti-frost agent.

4. The preparation method according to claim 1, characterized in that, In step (2), the mixing temperature is ≤30℃ and the time is 8~10min.

5. The preparation method according to claim 1, characterized in that, In step (2), the number of layers of the multi-layered fabric structure is not less than 3; the thickness of the multi-layered fabric structure is consistent with the wall thickness of the silicone tube, and the type of raw material of each layer of the silicone tube is selected according to the performance requirements of the silicone tube.

6. The preparation method according to claim 1, characterized in that, In step (3), the pressure of mold closing is 10±1MPa; the volume of the silicone tube is not greater than the remaining volume after the inner core is placed in the product mold cavity.

7. The preparation method according to claim 1, characterized in that, The combined mold used in the preparation method includes a product vulcanization mold and a soft core vulcanization mold; the soft core vulcanization mold is used to form a hollow soft core for preparing silicone tubes; the product vulcanization mold includes an upper product mold, a lower product mold, and a product mold cavity formed therebetween; after the soft core is assembled at both ends by an air inlet retaining ring and an end retaining ring, it is placed in the product mold cavity to form a silicone tube.

8. The preparation method according to claim 7, characterized in that, The soft core vulcanization mold includes an upper soft core mold, a lower soft core mold, and a soft core mold cavity formed therebetween; the soft core mold cavity contains a solid hard core for forming the hollow structure of the soft core.

9. The preparation method according to claim 7, characterized in that, The inlet retaining ring has a gas channel axially arranged in the middle; the gas channel is used to introduce nitrogen gas; the end retaining ring is sealed.

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