CN201224784Y - Apparatus for removing dissolvent in polyethylene fiber - Google Patents

Abstract

The utility model discloses a device for removing solvent in polyethylene fibers, which comprises two or more rollers, wherein the two rollers can be in contact with a certain pressure, and the rollers are fixed on a fixing device. Compared with the prior art, the device for removing solvent in polyethylene fiber provided by the utility model can save extraction agent and improve extraction efficiency, and is especially suitable for preparing polyethylene fiber.

Description

Device for removing solvent from polyethylene fibers

technical field

The utility model relates to the production of polyethylene fibers, in particular to a device for removing solvent in polyethylene fibers.

Background technique

Ultra high molecular weight polyethylene (UHMWPE) fiber is also called high strength high module polyethylene (HSHMPE) fiber or elongation chain polyethylene (ECPE) polyethylene fiber or high performance polyethylene (high Performance polyethylene (HPPE for short) fiber or high module polyethylene (high module polyethylene for short HMPE) fiber generally refers to polyethylene fiber with a weight average molecular weight of (1~6)× ¹⁰⁶ , and sometimes the weight average molecular weight will be higher than this Value, this kind of fiber is referred to as polyethylene fiber for short in the utility model.

Polyethylene fiber was first developed and manufactured by DSM company in the Netherlands. The method adopted is the gel spinning-super-stretching method. The basic principle is: ultra-high molecular weight polyethylene is dissolved in a suitable solvent at a certain temperature and a certain concentration, and the polyethylene molecules can be untangled at this time. , Then the solution is spun through a spinneret and then stretched, the polyethylene molecular chains are further stretched, the molecular chains are arranged in parallel, and the regularity is very high, forming highly crystalline polyethylene fibers. The polyethylene molecular chain in the polyethylene fiber is highly stretched, the degree of orientation reaches more than 95%, and the degree of crystallinity reaches more than 85%. The internal structure of polyethylene fiber determines its excellent mechanical properties, wear resistance and chemical stability. Therefore, once the polyethylene fiber came out, it has been widely concerned by countries all over the world and has developed rapidly. my country's Donghua University has done more in-depth research on this fiber and has achieved fruitful research results.

At present, the main process steps for manufacturing polyethylene fibers are: dissolving ultra-high molecular weight polyethylene in the first solvent and preparing polyethylene solution or suspension under a certain temperature and pressure, and then extruding it by a screw extruder , after being sprayed out from the spinning box, it is rapidly cooled and solidified into gel fibers or jelly filaments to obtain nascent fibers. The primary fiber is then extracted from the first solvent with a volatile second solvent or an extractant, and finally subjected to super-multiple thermal drawing and heat setting processes to finally obtain the finished fiber.

The ultra-high molecular weight polyethylene primary fiber formed by gel spinning contains a large amount of first solvent inside, the network structure is relatively loose, the force between the polyethylene polymer chains is small, and the polymer chains will be separated during stretching. Therefore, it is difficult to effectively stretch the orientation of polymer chains, and it is impossible to produce high-strength and high-modulus polyethylene fiber products. Therefore, it is necessary to remove a large amount of solvent or the first solvent present in the fiber through extraction and drying processes before stretching.

The degree of removal of solvent has a great influence on the performance of the final product of polyethylene fiber, so the step of removing solvent in polyethylene fiber is very important.

For the first solvent, Honeywell in the United States and some companies in Japan and China use paraffin oil, which is also called mineral oil or white oil. Generally, it is a mixture of hydrocarbons with a boiling point higher than 300°C.

The requirement for the second solvent or extractant is not only to have excellent extraction effect and certain volatility, but also to have the characteristics of low toxicity, safety, and low price.

The existing method of solvent removal is to directly extract the as-spun fibers with the extractant. The extraction process includes countercurrent, parallel flow, cross-flow and spraying, among which the cross-flow method can ensure that the fibers with solvent and The high-purity extractant is contacted, and the extraction speed is fast, but the consumption of the extractant is large, and the cost of extractant recovery is high; , the content of the first solvent in the extractant is already high, and the difference between the concentration of the first solvent in the extractant and the concentration of the first solvent in the fiber is smaller than that of cross-flow or counter-flow, so the first solvent in the polyethylene fiber The solvent removal effect is poor; in the countercurrent extraction method, because the high-purity extractant contacts the fiber that is about to leave the extraction equipment, although the first solvent content in the fiber is lower, it is still higher than the first solvent in the high-purity extractant content, the solvent can still be removed from the fiber, so more countercurrent extraction methods are used.

However, regardless of the extraction method of countercurrent, cocurrent, crossflow or spraying, the primary fiber is directly extracted. If the first solvent in the polyethylene fiber is to be removed well, the amount of extraction agent must be increased. It can well remove the first solvent in the polyethylene fiber.

Utility model content

An object of the present utility model is to provide a method for removing the solvent in the polyethylene fiber, which can remove the first solvent in the polyethylene fiber well by using less extractant.

Another object of the present utility model is to provide a device for removing solvent in polyethylene fibers, which can realize the above method for removing solvent in polyethylene fibers.

In order to achieve the above utility model purpose, the utility model provides the following technical solutions:

A method for removing solvent in polyethylene fibers, comprising the steps of:

a) extruded polyethylene fibers;

b) extracting the solvent in the polyethylene fibers that have been subjected to step a).

In the prior art, regardless of the extraction method of countercurrent, cocurrent, crossflow or spraying, the as-spun fibers are directly extracted with an extraction agent to obtain polyethylene fibers without the first solvent or with a low content of the first solvent. of polyethylene fibers. The designer found in the long-term engineering application and research that before the extraction of the as-spun fiber, the content of the first solvent in the as-spun fiber is very high, and if it is extracted with an extractant, it will consume a lot of solvents to achieve complete removal. The designer proposes to introduce a step of extruding polyethylene fibers before extraction. Of course, the principle of extrusion is not to damage polyethylene fibers. This principle is well known to those skilled in the art. After the step, in the case of using the same quality of the second solvent, the content of the first solvent in the extracted polyethylene fiber is significantly reduced. If the requirements for the content of the solvent in the polyethylene fiber after the extraction treatment are not changed, more than 20% of the extraction agent can be saved.

The solvent in the polyethylene fiber described in the utility model refers to the first solvent in the polyethylene fiber, which is used to dissolve the polyethylene fiber, such as white oil, and the second solvent refers to the extraction agent. The first solvent used in the extraction of polyethylene fibers.

Preferably, the extruded polyethylene fibers in step a) are extruded polyethylene fibers with a flexible material and another material.

Preferably, the flexible material in step a) is rubber.

Preferably, the other material mentioned in step a) is a rigid material, more preferably a metal material or an inorganic non-metal material, wherein the metal material is further preferably a stainless steel material, and the inorganic non-metal material is further preferably a ceramic material.

Preferably, the extractant used in step b) is selected from solvent naphtha, kerosene, benzene, toluene, xylene, chlorofluorocarbons, petroleum ether and halogenated hydrocarbons.

A device for removing solvent in polyethylene fibers, comprising two or more than two rollers, the rollers are fixed on a support, wherein the two rollers can be in contact with a certain pressure, and the rollers are fixed on a fixing device.

The device for removing the solvent in the polyethylene fiber is used before the extraction operation. There are two rollers that can be in contact with a certain pressure, and the polyethylene fiber is passed between the two rollers. The polyethylene fiber is under the action of pressure, wherein Part of the first solvent is squeezed out, so that part of the first solvent in the polyethylene fiber can be removed under mechanical action, which reduces the pressure of subsequent extraction and reduces the amount of extraction agent. Combined with the subsequent extraction operation, the introduction of this device can well remove the first solvent in the polyethylene fiber with a small amount of extraction agent.

Preferably, one of the rolls is a roll of flexible material, more preferably a roll of rubber.

Preferably, one of the rollers is a stainless steel roller.

Preferably, there is a solvent collection container below the roller.

The device for removing the solvent in the polyethylene fiber provided by the utility model can save the extraction agent, improve the extraction efficiency and improve the performance of the polyethylene fiber, and is especially suitable for preparing the polyethylene fiber.

Description of drawings

Fig. 1 is a schematic diagram of a method for removing solvent in polyethylene fibers in the prior art.

Fig. 2 is a schematic diagram of the first embodiment of the method for removing solvent in polyethylene fibers described in the present invention.

Fig. 3 is a schematic diagram of the first embodiment of the device for removing solvent in polyethylene fibers described in the present invention.

In the accompanying drawings, the numbers are: 101—polyethylene fiber, 102—extraction tank, 103a—rubber roller, 103b—stainless steel roller, 104—support, 105—solvent collection container.

Detailed ways

The utility model provides a method for removing solvent in polyethylene fibers, comprising the following steps:

a) extruded polyethylene fibers;

b) extracting the solvent in the polyethylene fibers that have been subjected to step a).

In order to better enable those skilled in the art to better understand the technical solutions of the present utility model, further detailed description will be made below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Fig. 1, Fig. 1 is a schematic diagram of a method for removing solvent in polyethylene fiber in the prior art, polyethylene fiber 101 advances according to the direction shown in the figure, and the direction of advancement is opposite to the flow direction of the extractant, polythene Vinyl fibers 101 go directly to extraction tank 102 without pretreatment. Please refer to Fig. 2, Fig. 2 is the first embodiment of the method for removing the solvent in the polyethylene fiber described in the utility model, compared with the prior art shown in Fig. 1 to remove the solvent in the polyethylene fiber 101 In this embodiment, before the polyethylene fiber 101 enters the extraction tank 102, a process of extruding the polyethylene fiber 101 is used to remove part of the solvent therein.

In this embodiment, extruding the polyethylene fiber 101 is accomplished by a rubber roller 103a and a stainless steel roller 103b. There needs to be a certain pressure between the rubber roller 103a and the stainless steel roller 103b. The principle of selecting the pressure is to increase the pressure as much as possible without damaging the polyethylene fiber 101. In this embodiment, for the polyethylene fiber 101 composed of 1000 The pressure between vinyl tow, selected rubber roller 103a and stainless steel roller 103b is 2-100N, preferably 5-50N, more preferably 10-40N, most preferably 10-20N.

The material of the rubber roller 103a can be selected as oil-resistant rubber, such as ethylene-propylene rubber, butyl rubber, fluorine rubber, and the like. Specifically, you can choose: binary ethylene propylene rubber, ternary ethylene propylene rubber, nitrile rubber, fluorosilicone rubber, epichlorohydrin rubber, etc.

The materials for the stainless steel roller 103b can be selected from the following types: ferritic stainless steel, austenitic stainless steel, austenitic-ferritic duplex stainless steel and martensitic stainless steel.

The rubber roller 103a and the stainless steel roller 103b can also be replaced by other flexible materials and rigid materials. The flexible material can also use other types of elastomers, such as rubber and thermoplastic mixed products, rubber and thermosetting plastic mixed products, and the like. Rigid materials can also be metals such as iron and ceramics, inorganic non-metallic materials, etc., or plastics or composite materials with sufficient hardness, such as polycarbonate, polyimide, glass fiber reinforced composite materials, carbon fiber reinforced composite materials, Aramid fiber reinforced composite materials, etc.

The process of extruding the polyethylene fiber 101 can be completed in addition to two rollers, and can also be in other forms, such as rollers and flat plates, or flat plates and flat plates. Specific options include: rubber roller and stainless steel plate, stainless steel roller and rubber plate, rubber plate and stainless steel plate, etc. When there is a flat plate structure in the extrusion structure, the surface of the roller or the flat plate is preferably smooth to reduce the friction between the two extrusion mechanisms and reduce the damage to the polyethylene fiber 101 .

In the process of extruding polyethylene fiber 101, a mechanism for multiple extrusion of polyethylene fiber 101 can also be set, for example, multiple sets of rubber rollers 103a and stainless steel rollers 103b can be set, multiple sets of rollers and flat plates can be set, and multiple sets of flat plates and flat plates can be set .

During the process of extruding the polyethylene fiber 101, since the solvent is continuously extruded from the polyethylene fiber 101, a solvent collection container can be provided under the extrusion structure.

The extruded polyethylene fiber 101 enters the extraction tank 102, and in the extraction tank 102, the flow direction of the extractant is opposite to that of the polyethylene fiber 101, that is, the countercurrent extraction method, because the high-purity extractant is prior to the In contact with the fiber leaving the extraction apparatus, the solvent can still be removed from the fiber despite the lower but still higher content of the first solvent in the high-purity extractant.

The extractant can be selected from solvent gasoline, kerosene, benzene, toluene, xylene, chlorofluorocarbons, petroleum ether, and halogenated hydrocarbons, as long as these extractants can reach the purity of industrial application level.

For more detailed content related to other polyethylene fibers in the production process, please refer to patent applications 03158881.6, 89107905.x, 90102855.x, 97106768.6, etc.

Utilize the method for removing the solvent in the polyethylene fiber described in the utility model, and specific embodiment is described as follows:

Example 1

The polyethylene powder with a weight average molecular weight of 5 million, additives, and solvent paraffin oil are thoroughly mixed and dissolved, and then enter the twin-screw extruder. Then it enters the spinning box and is extruded into filaments through the spinneret. After cooling in the coagulation bath water tank, gel fibers are formed, and then pass through the above-mentioned rubber roller 103a and stainless steel roller 103b. The pressure between the rubber roller 103a and the stainless steel roller 103b is 15N, which is the pressure for 1000 polyethylene fibers. The extruded polyethylene fibers are extracted with solvent gasoline. The extraction equipment is an extraction tank made of stainless steel, and the extraction adopts three-stage countercurrent extraction, and the extraction temperature is 20°C. Water is added to the extraction equipment to form a water seal with a thickness of 5 cm. Then enter the drying box for drying treatment, the drying temperature is 35 ℃. The dry gas is air. The dried fibers are hot-drawn to produce finished polyethylene fibers.

Comparative Example 2

The polyethylene powder with a weight average molecular weight of 5 million, additives, and solvent paraffin oil are thoroughly mixed and dissolved, and then enter the twin-screw extruder. Then it enters the spinning box and is extruded into filaments through the spinneret. After cooling in a coagulation bath, gel fibers are formed. Then use solvent gasoline for extraction. The extraction equipment is an extraction tank made of stainless steel, and the extraction adopts three-stage countercurrent extraction, and the extraction temperature is 20°C. Water is added to the extraction equipment to form a water seal with a thickness of 5 cm. Then enter the drying box for drying treatment, the drying temperature is 35 ℃. The dry gas is air. The dried fibers are hot-drawn to produce finished polyethylene fibers.

Example 3

The polyethylene fibers prepared in Example 1 and Comparative Example 2 were tested for solvent content and mechanical properties respectively, and the specific data are shown in Table 1.

Table 1 Comparison of properties of polyethylene fibers prepared by different examples

testing sample Tensile strength (cN/dtex) Tensile modulus (cN/dtex) Solvent content (weight content) Example 1 30 950 0.75% Comparative Example 1 28 940 1.2%

From the above under the same test conditions, it can be seen that the solvent content in the final polyethylene fiber is significantly lower than that without pre-extrusion, and the mechanical properties are also improved. cN/dtex in Table 1 is the unit of specific stress, c stands for one percent, N stands for cattle, and dtex stands for dtex.

Please refer to Fig. 3, Fig. 3 is a schematic diagram of the first embodiment of the device for removing solvent in polyethylene fiber according to the present invention. In this embodiment, the device for removing the solvent in the polyethylene fiber includes two rubber rollers 103a, two stainless steel rollers 103b, and a solvent collection container 105 located below the rubber rollers 103a and the stainless steel rollers 103b.

The material of the rubber roller 103a can be selected as oil-resistant rubber, such as ethylene-propylene rubber, butyl rubber, fluorine rubber, and the like. Specifically, you can choose: binary ethylene propylene rubber, ternary ethylene propylene rubber, nitrile rubber, fluorosilicone rubber, epichlorohydrin rubber, etc.

The materials for the stainless steel roller 103b can be selected from the following types: ferritic stainless steel, austenitic stainless steel, austenitic-ferritic duplex stainless steel and martensitic stainless steel.

The rubber roller 103a and the stainless steel roller 103b can also be replaced by other flexible materials and rigid materials. The flexible material can also use other types of elastomers, such as rubber and thermoplastic mixed products, rubber and thermosetting plastic mixed products, and the like. Rigid materials can also be metals such as iron and ceramics, inorganic non-metallic materials, etc., or plastics or composite materials with sufficient hardness, such as polycarbonate, polyimide, glass fiber reinforced composite materials, carbon fiber reinforced composite materials, Aramid fiber reinforced composite materials, etc.

The diameters of the rubber roller 103a and the stainless steel roller 103b are equal to 100mm. The specific selection range may be 20-2000mm, preferably 20-1000mm, more preferably 20-500mm, most preferably 50-200mm.

The rubber roller 103a and the stainless steel roller 103b are fixed on the bracket 104 through a shaft coupling structure. It can also be connected by other connection methods, such as rivet connection, pin connection, key connection and the like. It is preferable that one of the rubber roller 103a and the stainless steel roller 103b can rotate, or both can rotate, so as to facilitate the drawing of the polyethylene fiber and prevent it from being damaged.

The number of rubber rollers 103a and stainless steel rollers 103b in this embodiment can be one or several.

A solvent collection container 105 is provided below the bracket 104 to collect the solvent extruded from the polyethylene fiber. The shape of solvent collecting container 105 can be shapes such as cuboid, square, cylinder, spherical cap, or the combination of these shapes, and the principle of selection is, the projected area of rubber roller 103a and stainless steel roller 103b on the vertical direction is in solvent collecting The solvent on the container 105 and flowing down from the rubber roller 103 a and the stainless roller 103 b can flow into the solvent collection container 105 .

In order to maintain a certain pressure between the rubber roller 103a and the stainless steel roller 103b, the self-weight of the rubber roller 103a can be utilized, or an elastic mechanism can be set on the support 104, and the elastic mechanism can be a spring mechanism or a rubber mechanism. The support 104 can be fixed on the ground or be movable. For example, wheels can be installed on the bottom of the support 104, which can be easily moved when needed. In addition, because the support needs to bear a certain lateral force, the process of the support It needs to be able to be fixed during the process. For the state where the wheels are installed, a self-locking device is required during the process. If the friction of the wheel is sufficient to resist the lateral force on the bracket, then the self-locking device is no longer needed.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the scope of protection of the present utility model.

Claims (5)

1, a kind of device of removing the solvent in the polyethylene fiber is characterized in that, comprises two or more roller, and wherein two rollers can be with certain pressure contact, and described roller is fixed on the fixture.

2, the device of the solvent in the removal polyethylene fiber according to claim 1 is characterized in that, it is the flexible material roller that a roller is arranged.

3, the device of the solvent in the removal polyethylene fiber according to claim 2 is characterized in that, described flexible material roller is a rubber rollers.

4, the device of the solvent in the poly-second fiber of removal according to claim 3 is characterized in that it is stainless steel rider that a roller is arranged.

5, according to the device of the solvent in any described removal polyethylene fiber of claim 1-4, it is characterized in that also comprise the solvent collection container, described solvent collection container is positioned at the below of described roller.

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