A long straight vulcanization production process of a soft core rubber tube

Abstract

The application discloses vulcanization flat plate with expansion and contraction device, comprising several vulcanization modules, each vulcanization module is composed of vulcanization disc and vulcanization disc frame; the vulcanization disc frame is square frame welded by square tubes, along the length direction, the front end and the end of the square tube of the vulcanization module are respectively provided with bolt hole for bolt passing; two adjacent vulcanization modules are connected by connecting device, realizing free sliding of one vulcanization module relative to adjacent vulcanization module in horizontal direction. The application also discloses long straight vulcanization production process of soft core rubber tube, comprising: cutting the soft core rubber tube blank produced by soft core method to obtain long rubber tube blank, placing the long rubber tube blank on the vulcanization flat plate with expansion and contraction device, placing the vulcanization flat plate on the vulcanization frame, pushing into the vulcanization cylinder for vulcanization, removing the core rod of the rubber tube by water pressure, obtaining rubber tube finished product. The rubber tube produced based on the vulcanization process is straight, without bending radius, and does not bring negative influence to the radial mechanical property of the soft tube.

Description

Technical Field

[0001] This invention belongs to the field of hose manufacturing and relates to a vulcanization process for long and straight flexible hoses. Background Technology

[0002] Rubber hoses generally consist of an inner rubber layer, a reinforcing layer, and an outer rubber layer. Depending on the actual working conditions of the rubber hose, the reinforcing layer can be classified as braided, spiral, knitted, or fabric-reinforced. Rubber hoses are also classified according to different manufacturing methods, including cored production and coreless production.

[0003] Core-based production methods are further divided into hard-core and soft-core methods. While the hard-core method is a mature technology that effectively guarantees quality, its single-product length is limited by factors such as site, equipment, and operation. Cutting to the required length generates a large amount of waste, resulting in very low material utilization, typically only 70-85%. Furthermore, it suffers from low production efficiency and high labor intensity. Compared to the hard-core method, the soft-core method effectively addresses a series of its shortcomings, allowing for significantly longer lengths. The soft-core method requires coiling the uncured pre-formed hose onto a vulcanizing disc for curing, inevitably resulting in a certain bending radius. This, to some extent, damages the structure of the hose's reinforcing skeleton layer, negatively impacting the hose's radial mechanical properties. The overall stability of the hose is poor, and hose bending leads to inconvenience during installation and use, especially in the relatively confined spaces of automotive hose installations. Additionally, the vulcanization process requires external wrapping of the hose, a cumbersome procedure that reduces production efficiency, consumes significant manpower and resources, and increases product costs. Although hoses produced by the soft core manufacturing method can be vulcanized using salt bath or microwave continuous vulcanization, salt bath continuous vulcanization has a significant impact on appearance, especially for hoses without a coating process. It inevitably causes surface contamination and mechanical damage to automotive hoses. Furthermore, the molten salt steam and wastewater generated during cleaning are technical limitations of the salt bath continuous vulcanization method. Microwave continuous vulcanization has high requirements regarding rubber type, formulation, and compound quality. Moreover, hoses with multi-layered reinforcing materials are technically unsuitable for microwave vulcanization. Under the simultaneous action of high temperature, high pressure, and electromagnetic waves, the fibers must not degrade, and the shrinkage rate must not be too high. Otherwise, the hose's pressure resistance will not meet requirements, and excessive shrinkage will make it difficult to control the hose's appearance and dimensions.

[0004] Chinese patent application CN102120349A discloses a method for continuous vulcanization production of automotive brake hoses. This method requires a large space for equipment and has high investment costs. Furthermore, it is difficult to guarantee the consistency of the hose's state before and after vulcanization in the vulcanization channel. Summary of the Invention

[0005] The purpose of this invention is to address the problems and defects of the hose core rod production method by providing a vulcanizing plate with expansion and contraction devices, and a novel long straight hose core vulcanization production process based on this vulcanizing plate. This process is suitable for long straight hoses produced by the soft core method. During the vulcanization process, the hose does not need to be coated with resin or coiled. The hose is directly placed on the vulcanizing plate for molding. On the one hand, this method has the advantages of smooth hose surface, simple production process, low cost, and high efficiency. On the other hand, the hose produced by this method is straight and has no bending radius, which will not have a negative impact on the radial mechanical properties of the hose. The overall performance of the hose is stable, and the installation and use process will not be inconvenient due to hose bending.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A vulcanizing plate with an expansion and contraction device includes several vulcanizing modules. Each vulcanizing module consists of a vulcanizing disc 1 and a vulcanizing disc frame 2. The vulcanizing disc 1 has evenly distributed small holes. The vulcanizing disc frame 2 is a square frame welded from square tubes. Along the length direction, bolt holes for bolts to pass through are provided at the front and rear ends of the square tubes of the vulcanizing module. Adjacent vulcanizing modules are connected by a connecting device, which enables one vulcanizing module to slide freely relative to the adjacent vulcanizing module in the horizontal direction.

[0008] The vulcanizing disc 1 is made of stainless steel.

[0009] The vulcanizing disc 1 has a length of 3.0±0.5m and a width of 1.0±0.5m.

[0010] The aperture of the small hole is 7.0±3.0mm, and the opening ratio is 50±10%.

[0011] The vulcanizing disc 1 is welded onto the vulcanizing disc frame 2.

[0012] The connecting device includes a connecting square rod 3, one end of which has a horizontal square hole and the other end has a bolt hole for bolts to pass through. The two ends of the connecting square rod are respectively inserted into the square tubes of two adjacent vulcanizing modules and fixed by bolts and nuts. One end of the connecting square rod 3 is fixed to the vulcanizing module and cannot slide, while the other end of the connecting square rod 3 is fixed to the adjacent vulcanizing module and can slide in the horizontal direction.

[0013] The distance that the vulcanizing module slides relative to the adjacent vulcanizing module in the horizontal direction is 0 to 30 mm.

[0014] Another objective of this invention is to provide a long straight vulcanization production process for soft-core rubber hoses, comprising: directly cutting a rubber hose blank with a mandrel produced by the soft-core method to a fixed length to obtain a long rubber hose blank; placing the long rubber hose blank on a vulcanization plate equipped with an expansion and contraction device; placing the vulcanization plate on a vulcanization frame and pushing it into a vulcanization cylinder for vulcanization; after vulcanization, removing the mandrel from the hose by water pressure to obtain the finished rubber hose.

[0015] The hose is a 30-60m long hose.

[0016] The core rod is a soft core rod made of rubber or soft plastic.

[0017] The inner diameter Φ of the hose is 3.0 to 8.0 mm, and the outer diameter Φ is 8.0 to 16.0 mm.

[0018] The hose comprises an inner rubber layer, a reinforcing layer, and an outer rubber layer.

[0019] Preferably, the hose includes an inner rubber layer, a reinforcing layer, a middle rubber layer, a reinforcing layer, and an outer rubber layer.

[0020] Each reinforcing layer can be any one of a woven structure reinforcing layer, a wound structure reinforcing layer, or a knitted structure reinforcing layer.

[0021] Preferably, each reinforcing layer is a woven structure reinforcing layer.

[0022] More preferably, each reinforcing layer is a polyester fiber woven layer.

[0023] The hose of this invention has a fiber-reinforced structure, and the inner diameter Φ of the hose is controlled to be 3.0 to 8.0 mm to avoid indentation defects caused by vulcanization when the inner diameter is >8.0 mm.

[0024] The soft-core method of this invention for producing cored tubing preforms is a conventional process in the field, including: batching, internal mixing, compounding, extruding the rubber strip, core extrusion molding, braiding, extrusion molding, cutting, vulcanization, and core removal; or including: batching, internal mixing, compounding, extruding the rubber strip, core extrusion molding, braiding, intermediate rubber coating and simultaneous braiding, extrusion molding, cutting, vulcanization, and core removal.

[0025] Specifically, the long straight vulcanization production process of the flexible core rubber hose described in this invention includes the following steps:

[0026] Step (1): Ingredient preparation, intensive mixing, compounding, and extrusion of rubber strips to obtain an inner layer rubber and outer layer rubber composition;

[0027] Step (2): The core release device releases the core rod, which passes through the coating tank containing the release agent, so that the surface of the core rod is evenly coated with a layer of release agent to facilitate core release.

[0028] Step (3): The mandrel enters the extruder to extrude the inner layer of rubber to obtain the inner rubber layer; the inner rubber layer covering the mandrel enters the knitting machine, winding machine or braiding machine through the guide roller, and a reinforcing layer is covered on the outside of the inner rubber layer. The tube with the reinforcing layer is obtained by winding through the hub.

[0029] Step (4): The rubber hose with the reinforcing layer is fed into the outer extruder through the traction machine to coat the outer rubber, and the outer rubber is extruded to obtain the rubber hose blank. The rubber hose blank is fed into the cooling tank through the traction device for cooling.

[0030] Step (5): After cooling, the hose is directly wound onto the hub. The hose blank wound onto the hub is cut to a fixed length to obtain a long hose blank. A layer of long hose blanks is placed on a vulcanizing plate with expansion and contraction devices. The vulcanizing plate is then placed on the vulcanizing frame and pushed into the vulcanizing cylinder for vulcanization. The vulcanization temperature is 160℃~165℃, the vulcanization pressure is 0.55~0.65MPa, and the vulcanization time is 40~60min.

[0031] Step (6): The hose is decoupled from the mandrel by a water pressure pump to obtain the finished hose.

[0032] Or may include the following steps:

[0033] Step (1): Ingredient preparation, intensive mixing, compounding, and extrusion of rubber strips to obtain an inner layer rubber and outer layer rubber composition;

[0034] Step (2): The core release device releases the core rod, which passes through the coating tank containing the release agent, so that the surface of the core rod is evenly coated with a layer of release agent to facilitate core release.

[0035] Step (3): The mandrel enters the extruder to extrude the inner rubber layer to obtain the inner rubber layer; the inner rubber layer covering the mandrel enters the knitting machine, winding machine or braiding machine through the guide roller, and a reinforcing layer is covered on the outside of the inner rubber layer. Then, when the intermediate rubber is coated, a polyester fiber reinforcing layer is covered simultaneously. If the reinforcing layer is a multi-layer composite structure, it can be continuously braided by multiple parallel braiding machines and wound up by the hub to obtain the rubber tube with the reinforcing layer.

[0036] Step (4): The rubber hose with the reinforcing layer is fed into the outer extruder through the traction machine to coat the outer rubber, and the outer rubber is extruded to obtain the rubber hose blank. The rubber hose blank is fed into the cooling tank through the traction device for cooling.

[0037] Step (5): After cooling, the hose is directly wound onto the hub. The hose blank wound onto the hub is cut to a fixed length to obtain a long hose blank. A layer of long hose blanks is placed on a vulcanizing plate with expansion and contraction devices. The vulcanizing plate is then placed on the vulcanizing frame and pushed into the vulcanizing cylinder for vulcanization. The vulcanization temperature is 160℃~165℃, the vulcanization pressure is 0.55~0.65MPa, and the vulcanization time is 40~60min.

[0038] Step (6): The hose is decoupled from the mandrel by a water pressure pump to obtain the finished hose.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. Because the vulcanizing plate designed as a whole is prone to stress deformation under high temperature vulcanization, causing the rubber tube placed on it to bend and deform, this invention divides the entire vulcanizing plate into several individual vulcanizing modules; at the same time, a retractable gap is reserved at the connection between two adjacent vulcanizing modules. The reserved retractable gap can provide horizontal movement space for the vulcanizing plate when it expands. Under high temperature heating conditions, the connecting square rod drives the vulcanizing module to slide horizontally relative to the adjacent vulcanizing module, which can release the stress deformation generated under high temperature.

[0041] The vulcanizing plate of this invention provides excellent buffering against the contact pressure between the vulcanizing plate and the hose, ensuring a long and straight vulcanization effect for the hose. Based on the vulcanizing plate with its special expansion and contraction device, hoses produced using the soft-core method do not require resin coating or coiling and can be directly vulcanized. This reduces the resin peeling process after vulcanization, resulting in a simpler, lower-cost, more efficient, and energy-saving production process. It significantly reduces energy consumption and shortens production time, producing hoses with a smooth appearance and uniform dimensions.

[0042] 2. The hollow design of the vulcanizing disc in this invention serves two purposes: first, it ensures that steam can flow smoothly between the upper and lower vulcanizing discs during vulcanization, thus guaranteeing uniform vulcanization; second, it prevents condensed water vapor from remaining on the upper surface of the vulcanizing disc, avoiding localized incomplete vulcanization of the product and affecting its performance.

[0043] 3. The hose produced by the method of the present invention has no bending radius, which will not have a negative impact on the radial mechanical properties of the hose. The overall performance of the hose is stable, and the installation and use process will not be inconvenient due to hose bending. At the same time, the hose will not interfere with the surrounding environment during installation and use.

[0044] 4. The method of the present invention is applicable to the production of rubber long hoses of various specifications and structural types, and has high practicality for enterprise production. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of the vulcanizing plate with expansion and contraction devices of the present invention;

[0046] Figure 2 for Figure 1 Top view;

[0047] Figure 3 This is a schematic diagram showing the connection between two adjacent vulcanizing modules in the vulcanizing plate with expansion and contraction devices of the present invention.

[0048] In the diagram, 1-vulcanizing disc, 2-vulcanizing disc frame, 3-connecting device, 4-bolt. Detailed Implementation

[0049] The technical solution of the present invention will be described in detail through specific embodiments.

[0050] Example 1

[0051] like Figures 1-3 As shown, a vulcanizing plate with expansion and contraction devices includes several vulcanizing modules. Each vulcanizing module consists of a vulcanizing disc 1 and a vulcanizing disc frame 2. The vulcanizing disc 1 is welded to the vulcanizing disc frame 2. The vulcanizing disc 1 is made of stainless steel and has evenly distributed holes with a diameter of 7.0±3.0 mm, with an opening rate of 50±10%. The vulcanizing disc frame 2 is a square frame welded from square tubes. Along the length direction, bolt holes for bolts to pass through are provided at the front and rear ends of the square tubes of the vulcanizing module. Adjacent vulcanizing modules are connected by a connecting device, which includes a connecting square rod 3. One end of the connecting square rod 3 has a horizontal square hole, and the other end has a bolt hole. The bolts pass through the bolt holes, and the diameter of the bolt holes is consistent with the outer diameter of the bolts; the two ends of the connecting square rod 3 are respectively inserted into the square tubes of two adjacent vulcanizing modules. The bolts 4 pass through the bolt holes of the vulcanizing disc frame 2 and the connecting square rod 3 and are fixed by nuts. The bolts 4 pass through the bolt holes of the vulcanizing disc frame 2 and the square holes of the connecting square rod 3 and are fixed by nuts. One end of the connecting square rod 3 is fixed to the vulcanizing module and cannot slide. The other end is fixed to the adjacent vulcanizing module and can slide in the horizontal direction, thereby realizing that one of the vulcanizing modules can slide freely in the horizontal direction relative to the adjacent vulcanizing module. The distance that the vulcanizing module can slide freely in the horizontal direction relative to the adjacent vulcanizing module is 0 to 30 mm.

[0052] The vulcanizing disc 1 has a length of 3.0±0.5m and a width of 1.0±0.5m.

[0053] The bolt is a hexagonal bolt, and the nut is a hexagonal nut. A flat washer and a spring washer are provided between the bolt and the nut. The main function of the flat washer and the spring washer is to prevent the bolt and nut from loosening during long-term use. Generally, the flat washer is installed first, then the spring washer is added, and finally the nut is added and tightened.

[0054] Example 2

[0055] This embodiment is an EPDM rubber hose with a single hose length of 40 meters, an inner diameter of 3.2 mm, an outer diameter of 10.2 mm, and a reinforcing layer of double-braided polyester fiber layer. The inner and outer rubber layers of the EPDM rubber hose are made of inner EPDM rubber composition and outer EPDM rubber composition, respectively, and the middle rubber layer is made of calendered low-permeability intermediate rubber composition.

[0056] The inner EPDM rubber composition is made of the following components in parts by weight: 100 parts of EPDM rubber Keltan 4450S, 70 parts of fast extrusion carbon black, 15 parts of silica Sillitin V85, 2 parts of antioxidant MMBI-70, 5 parts of zinc oxide, 1 part of stearic acid, 0.3 parts of sulfur, 3 parts of crosslinking agent DCP, and 2 parts of co-crosslinking agent TIAC-70.

[0057] The outer EPDM rubber composition is made of the following components in parts by weight: 100 parts of EPDM Keltan 5470C, 50 parts of fast-extrusion carbon black, 30 parts of high-abrasion carbon black N330, 15 parts of kaolin, 25 parts of paraffin oil, 1 part of antioxidant RD, 1 part of antioxidant MB, 5 parts of zinc oxide, 1 part of stearic acid, 0.5 parts of sulfur, 2 parts of accelerator DTDM, 0.5 parts of accelerator BZ, and 0.5 parts of accelerator PZ.

[0058] The calendered low-permeability intermediate rubber composition (Example 1 of Chinese Patent CN112442237A) is made from the following components in parts by weight: 65 parts of EPDM Keltan 8550C, 35 parts of halogenated butyl rubber CIIR-1301, 5 parts of zinc oxide, 1 part of stearic acid, 1 part of antioxidant RD, 1 part of antioxidant MB, 25 parts of high abrasion-resistant carbon black N330, 40 parts of general furnace black N660, 15 parts of talc; 20 parts of paraffin oil Nypar330, 1.5 parts of sulfur, 1 part of accelerator TBzTD-80, 1 part of accelerator CBS, and 1 part of accelerator ZBEC.

[0059] EPDM rubber hoses are manufactured using a long-straight vulcanization process, the specific steps of which are as follows:

[0060] Step (1): The rubber core release device releases a rubber soft core rod with a length of 1000±0.5m; the core rod passes through a coating tank containing LubeKote1830-2 rubber tube release agent, so that the outer surface of the core rod is uniformly coated with a layer of release agent.

[0061] Step (2): The mandrel enters the extruder to extrude the inner layer rubber to obtain the inner rubber layer. The inner rubber layer covering the mandrel enters the double layer braiding machine through the guide roller. After weaving a layer of polyester fiber reinforcement layer outside the inner rubber layer, it enters the intermediate rubber coating device. During the intermediate rubber coating, a layer of polyester fiber reinforcement layer is woven simultaneously. The tube with reinforcement layer is obtained by winding through the hub.

[0062] Step (3): The rubber hose with the reinforcing layer is fed into the outer extruder through the traction machine to be coated with the outer rubber. The hose blank is fed into the cooling water tank through the traction device for cooling.

[0063] Step (4): The cooled hose blank is directly wound onto the hub; the hose blank wound on the hub is cut to a fixed length of 40m to obtain a long hose blank. A layer of long hose blanks is placed on the vulcanizing plate with expansion and contraction device in Example 1, and then the vulcanizing plate is placed on the vulcanizing frame and pushed into the vulcanizing cylinder for vulcanization. Vulcanization is carried out at a temperature of 162℃ and a pressure of 0.6MPa for 45min.

[0064] Step (5) After vulcanization, the mandrel is removed by a water pressure pump to obtain the finished rubber hose. The finished rubber hose has a smooth appearance and the inner and outer diameters fully meet the requirements.

Claims

1. A vulcanized flat plate with expansion and contraction devices, characterized in that: The device includes several vulcanizing modules, each consisting of a vulcanizing disc and a vulcanizing disc frame. The vulcanizing disc has evenly distributed small holes. The vulcanizing disc frame is a square frame welded from square tubes. Along the length direction, bolt holes for bolts to pass through are provided at the front and rear ends of the square tubes of the vulcanizing module. Adjacent vulcanizing modules are connected by a connecting device, which includes a connecting square rod. One end of the connecting square rod has a horizontal square hole, and the other end has a bolt hole for bolts to pass through. The two ends of the connecting square rod are respectively inserted into the square tubes of the two adjacent vulcanizing modules and fixed by bolts and nuts. One end of the connecting square rod is fixed to the vulcanizing module and cannot slide, while the other end of the connecting square rod is fixed to the adjacent vulcanizing module and can slide in the horizontal direction. The connecting device allows one vulcanizing module to slide freely in the horizontal direction relative to the adjacent vulcanizing module.

2. The vulcanized flat plate with expansion and contraction device according to claim 1, characterized in that: The vulcanizing disc is made of stainless steel; the aperture of the small hole is 7.0±3.0 mm, and the opening ratio is 50±10%.

3. The vulcanized flat plate with expansion and contraction device according to claim 1, characterized in that: The distance that the vulcanizing module slides relative to the adjacent vulcanizing module in the horizontal direction is 0 to 30 mm.

4. A vulcanization process for producing long, straight flexible rubber hoses, characterized in that: include: The mandrel-lined hose blank produced by the soft core method is cut to a fixed length to obtain a long hose blank. The long hose blank is placed on the vulcanizing plate with expansion and contraction device as described in any one of claims 1-3. The vulcanizing plate is placed on the vulcanizing frame and pushed into the vulcanizing cylinder for vulcanization. After vulcanization, the mandrel is removed by water pressure to obtain the finished hose.

5. The vulcanization production process for long straight flexible hoses according to claim 4, characterized in that... The length of the hose is 30-60m.

6. The vulcanization production process for long straight flexible hoses according to claim 4, characterized in that... The core rod is a soft core rod made of rubber or soft plastic.

7. The vulcanization production process for long straight flexible hoses according to claim 4, characterized in that... The hose comprises an inner rubber layer, a reinforcing layer, and an outer rubber layer.

8. The vulcanization production process for long straight flexible hoses according to claim 4, characterized in that... The inner diameter Φ of the hose is 3.0 to 8.0 mm, and the outer diameter Φ is 8.0 to 16.0 mm.

9. The vulcanization production process for long straight flexible hoses according to claim 4, characterized in that... The vulcanization temperature is 160℃~165℃, the vulcanization pressure is 0.55~0.65MPa, and the vulcanization time is 40~60min.

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