Solvent composition as well as preparation method and application thereof

Abstract

The invention provides a solvent composition as well as a preparation method and application thereof, and belongs to the technical field of high-pressure flash spinning. The solvent composition comprises the following components in percentage by volume: 20-40% of a non-polar solvent, 0.5-15% of a composite solubilizer and the balance of dichloromethane, the composite solubilizing agent comprises a first solubilizing agent and a second solubilizing agent, the first solubilizing agent is C1-C6 monohydric alcohol, and the second solubilizing agent is polyether; the solubility parameter of the non-polar solvent is 8.3 to 10.5. The solvent composition disclosed by the invention can be used for well dissolving the ultra-high molecular weight polyethylene and enabling a mutually entangled ultra-high molecular weight polyethylene network to be fluffy. After the ultra-high molecular weight polyethylene is dissolved in the solvent composition disclosed by the invention, the solvent composition is applied to preparation of the ultra-high molecular weight polyethylene fiber by high-pressure flash-jet spinning, undesirable conditions such as spinning fluid layering and filament breaking are not easy to occur, and the prepared ultra-high molecular weight polyethylene fiber has excellent modulus and strength.

Description

Technical Field

[0001] The present invention relates to the technical field of high-pressure flash spinning, and in particular to a solvent composition, a preparation method thereof, and an application thereof. Background Art

[0002] Ultra-high molecular weight polyethylene fiber, also known as high-strength and high-modulus polyethylene fiber, is a fiber spun from ultra-high molecular weight polyethylene (UHMWPE) with a molecular weight of 1 million to 6 million, and has excellent strength and modulus. In the military field, bulletproof and riot helmets made of resin composites reinforced with this fiber have become alternatives to steel helmets and aramid fiber-reinforced composite helmets. In aerospace engineering, due to the light weight, high strength, and good impact resistance of this fiber composite material, it is suitable for the wing tip structures of various aircraft, spacecraft structures, and buoyant aircraft. In addition, ultra-high molecular weight polyethylene fiber can also be used for ropes, cables, biomaterials, pressure-resistant containers in industry, conveyor belts, filter materials, automotive bumper plates, etc.

[0003] Ultra-high molecular weight polyethylene fiber is usually prepared by high-pressure flash spinning technology. High-pressure flash spinning technology, also known as flash spinning technology, refers to mixing a polymer with a solvent into a solution in a high-temperature and high-pressure environment and spraying it from a spinneret hole into a normal-temperature and normal-pressure environment. When the solvent changes from a liquid phase at high temperature and high pressure to a normal-temperature and normal-pressure environment, it will quickly evaporate, and the remaining polymer forms a fiber bundle containing many ultrafine fibers through extrusion, drawing, and scattering of the spinneret hole.

[0004] Prior art reports that when preparing polyethylene fiber by high-pressure flash spinning technology, dichloromethane is usually used as a solvent. However, for ultra-high molecular weight polyethylene, it can only be partially dissolved in dichloromethane, and even at a relatively high temperature, the solubility of ultra-high molecular weight polyethylene in dichloromethane is still low. If dichloromethane is used as the solvent for high-pressure flash preparation of ultra-high molecular weight polyethylene fiber, during the spinning process, phenomena such as spinning fluid stratification and discontinuous spinning will occur, which will lead to poor comprehensive performance of ultra-high molecular weight polyethylene fiber.

[0005] Chinese Patent Application CN 101148783 A discloses a dry spinning process method for preparing ultra-high molecular weight polyethylene fiber, including dissolving ultra-high molecular weight polyethylene in a xylene solvent, then extruding, spinning, and drying to remove xylene and other steps. Although this method can prepare ultra-high molecular weight polyethylene fiber, the operation of removing xylene must still be carried out, and the steps are cumbersome. Summary of the Invention

[0006] The object of the present invention is to overcome the defect of poor spinning effect of ultra-high molecular weight polyethylene fibers in the prior art, and to provide a solvent composition which can dissolve UHMWPE well and fluff up the entangled UHMWPE network. After UHMWPE is dissolved in the solvent composition of the present invention and applied to high-pressure flash spinning to prepare ultra-high molecular weight polyethylene fibers, it is not easy to appear adverse conditions such as layering and filament breakage of the spinning fluid, and the prepared ultra-high molecular weight polyethylene fibers have excellent modulus and strength.

[0007] Another object of the present invention is to provide a preparation method of the above solvent composition.

[0008] Another object of the present invention is to provide the application of the above solvent composition in the preparation of ultra-high molecular weight polyethylene fiber spinning.

[0009] Another object of the present invention is to provide a spinning method for ultra-high molecular weight polyethylene fibers, which uses the above solvent composition as a solvent.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A solvent composition, comprising components in the following volume percentages:

[0012] Non-polar solvent 20-40%,

[0013] Compound solubilizer 0.5-15%,

[0014] Methylene chloride as the balance;

[0015] The compound solubilizer includes a first solubilizer and a second solubilizer. The first solubilizer is a C1-C6 monohydric alcohol, and the second solubilizer is a polyether;

[0016] The solubility parameter of the non-polar solvent is 8.3-10.5.

[0017] The solvent composition of the present invention uses methylene chloride as a solvent matrix, and is compounded with a certain amount of non-polar solvent with a solubility parameter of 8.3-10.5 and a specific compound solubilizer, so that the solvent composition can dissolve ultra-high molecular weight polyethylene well and fluff up the entangled ultra-high molecular weight polyethylene network.

[0018] The non-polar solvent mainly plays a role in swelling ultra-high molecular weight polyethylene. The inventors have found through research that ultra-high molecular weight polyethylene can achieve a good swelling effect in the non-polar solvent of the present invention, with its volume expanding to a certain extent, thereby making the network structure of ultra-high molecular weight polyethylene itself that is intertwined and entangled become fluffy. Methylene chloride can mainly penetrate between the molecular chains of ultra-high molecular weight polyethylene and destroy the interaction between the molecular chains of ultra-high molecular weight polyethylene. Through the combined action of the non-polar solvent, the composite solubilizer, and methylene chloride, the dissolution of ultra-high molecular weight polyethylene is promoted. The composite solubilizer in the present invention includes a first solubilizer and a second solubilizer, where the first solubilizer is a C1-C6 monohydric alcohol and the second solubilizer is a polyether. On the one hand, the composite solubilizer can reduce the surface tension between ultra-high molecular weight polyethylene and the solvent phase (non-polar solvent, methylene chloride), increasing the surface activity at the two-phase interface, thereby further improving the solubility of ultra-high molecular weight polyethylene in the solvent composition; on the other hand, due to the use of two solubilizers for compounding, the solvent composition of the present invention can achieve good dissolution of ultra-high molecular weight polyethylene under both normal temperature and high temperature conditions.

[0019] Preferably, the non-polar solvent includes at least one of acetone, cyclohexanone, methyl isobutyl ketone, methyl acetate, ethyl acetate, and isobutyl acetate.

[0020] More preferably, the non-polar solvent is acetone.

[0021] In addition to the advantage of low toxicity, the inventors have found through research that acetone also has a relatively better swelling effect on ultra-high molecular weight polyethylene. Using a solvent composition with acetone as the non-polar solvent can make the properties of ultra-high molecular weight polyethylene fibers prepared by high-pressure flash spinning better.

[0022] Preferably, in the composite solubilizer, the first solubilizer accounts for 60-85 Vol%, and the second solubilizer accounts for 15-40 Vol%.

[0023] More preferably, in the composite solubilizer, the first solubilizer accounts for 65-75 Vol%, and the second solubilizer accounts for 25-35 Vol%.

[0024] In the composite solubilizer, it is preferred that the content ratio of the first solubilizer is relatively higher. This is because when the solvent composition is applied to high-pressure flash spinning, there is a process of heating from normal temperature to high temperature. Since the heating rate is slow, it is necessary to ensure that ultra-high molecular weight polyethylene can be dissolved at a non-high temperature for a long time. The boiling point of the C1-C6 monohydric alcohol is lower than that of the polyether, so it is preferred that the amount of the first solubilizer is higher.

[0025] Preferably, the boiling point of the first solubilizer ≤ 150 °C, and the boiling point of the second solubilizer is 200-350 °C.

[0026] Preferably, the first solubilizer includes at least one of methanol, ethanol, and propanol. More preferably, the first solubilizer is ethanol.

[0027] Preferably, the number-average molecular weight of the polyether is 400 to 5000, and more preferably the number-average molecular weight of the polyether is 400 - 4000.

[0028] The test method for the number-average molecular weight of the polyether is to test by gel permeation chromatography.

[0029] The polyether within the above molecular weight range has good miscibility with non-polar solvents and dichloromethane. In addition, the inventors have found through research that when the number-average molecular weight of the polyether is higher, the dispersing power for ultra-high molecular weight polyethylene is better, but the viscosity of the polyether increases with the increase of its number-average molecular weight, and when the viscosity is too high, it will have a certain negative impact on subsequent high-pressure flash spinning.

[0030] Optionally, the polyether includes at least one of propylene glycol block polyether, polypropylene glycol, and polyetheramine. The polyetheramine can be selected as terminal amino polyoxypropylene ether, and the propylene glycol block polyether can be selected as at least one of polyether F-38, polyether F-64, polyether F-61, polyether F-68, and polyether L-64.

[0031] Preferably, the solvent composition includes the following components in volume percentages:

[0032] Non-polar solvent 25 - 35%,

[0033] Compound solubilizer 5 - 12%,

[0034] Dichloromethane as the balance.

[0035] The present invention also protects a preparation method of the above solvent composition, which includes the following steps: mixing the non-polar solvent, the compound solubilizer, and dichloromethane evenly to obtain it.

[0036] The present invention also protects the application of the above solvent composition in the preparation of ultra-high molecular weight polyethylene fiber spinning.

[0037] After the ultra-high molecular weight polyethylene is dissolved in the solvent composition, it is applied to high-pressure flash spinning to prepare ultra-high molecular weight polyethylene fibers, and it is not easy to appear bad conditions such as spinning fluid stratification and filament breakage, and the obtained ultra-high molecular weight polyethylene fibers have excellent modulus and strength.

[0038] The present invention also protects a spinning method of ultra-high molecular weight polyethylene fibers, which includes the following steps:

[0039] Dissolve the ultra-high molecular weight polyethylene, antioxidant, and mineral oil in the solvent composition, and obtain a spinning fluid after mixing;

[0040] Under high temperature and high pressure conditions, the spinning fluid is ejected through the spinneret holes into the normal temperature and normal pressure environment to obtain the ultra-high molecular weight polyethylene fiber.

[0041] Specifically, ultra-high molecular weight polyethylene, antioxidant, and mineral oil are dissolved in the solvent composition. After mixing to obtain the spinning fluid, the spinning fluid is added to a reaction kettle, an inert gas is introduced to discharge the air in the reaction kettle, and pressure is applied to obtain a high-pressure environment. Further heating and temperature increase are carried out to make the environment in the reaction kettle reach high temperature and high pressure conditions. The spinneret hole valve is opened, so that the spinning fluid is ejected through the spinneret holes into the normal temperature and normal pressure environment. During the ejection process, the solvent composition in the spinning fluid rapidly evaporates, and the remaining ultra-high molecular weight polyethylene is extruded, drawn, and scattered through the spinneret holes, and finally a fiber bundle containing multiple ultra-high molecular weight polyethylene fibers is formed.

[0042] The viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 2 million to 5.8 million.

[0043] The test method for the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is as follows: measured by the viscosity method. Specifically, decalin is used as the solvent, the temperature is 135 °C, and an Ubbelohde viscometer is used to measure the outflow time of the polyethylene solution, and then the intrinsic viscosity η of the polymer is calculated; then according to the formula M γ = 5.37×10 4 ×[η] 1.37 The obtained M γ is the viscosity-average molecular weight of the polymer.

[0044] Mineral oil, as a good solvent for polyethylene, can promote the dissolution of ultra-high molecular weight polyethylene to a certain extent. The addition of an antioxidant helps to prevent the degradation of ultra-high molecular weight polyethylene at high temperatures.

[0045] Preferably, the mineral oil accounts for 1-4 vol% of the volume of the solvent composition.

[0046] Preferably, the high temperature and high pressure conditions are a temperature of 170-200 °C and a pressure of 7.0-9.0 mPa.

[0047] Preferably, the inert gas is at least one of carbon dioxide, nitrogen, and argon.

[0048] Preferably, the mineral oil includes at least one of mineral oil D60, mineral oil D80, mineral oil D100, and mineral oil D130.

[0049] Preferably, the antioxidant includes at least one of antioxidant 1010 and antioxidant 168.

[0050] Preferably, the ultra-high molecular weight polyethylene accounts for 5-16 wt.% of the mass of the solvent composition.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] The present invention has developed a solvent composition that can dissolve ultra-high molecular weight polyethylene well and fluff up the entangled ultra-high molecular weight polyethylene network. After the ultra-high molecular weight polyethylene is dissolved in the solvent composition of the present invention and applied to high-pressure flash spinning to prepare ultra-high molecular weight polyethylene fibers, problems such as layering and filament breakage of the spinning fluid are not likely to occur, and the obtained ultra-high molecular weight polyethylene fibers have excellent modulus and strength. Detailed implementation manners

[0053] To better illustrate the purpose, technical solutions and advantages of the present invention, the following will further illustrate the present invention in conjunction with specific embodiments, but the embodiments do not impose any form of limitation on the present invention.

[0054] In the examples and comparative examples of the present invention, the sources of the raw materials used are as follows:

[0055] Ultra-high molecular weight polyethylene:

[0056] UHMWPE-1, with a viscosity-average molecular weight of 5.8 million, 630M, Mitsui Chemicals, Japan;

[0057] UHMWPE-2, with a viscosity-average molecular weight of 3.3 million, 320MU, Mitsui Chemicals, Japan;

[0058] UHMWPE-3, with a viscosity-average molecular weight of 2 million, 240S, Mitsui Chemicals, Japan;

[0059] Polyether:

[0060] Polyether-1, with a number-average molecular weight of 1902, polyether L-31, propylene glycol block polyether, boiling point 200°C, 9003-11-6, Nantong Yuanlai New Materials Co., Ltd.;

[0061] Polyether-2, with a number-average molecular weight of 4000, polyetheramine, terminal amino polyoxypropylene ether, boiling point 232°C, 9046-10-0, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0062] Polyether-3, with a number-average molecular weight of 400, polypropylene glycol, boiling point 234.2°C, 25322-69-4, Shanghai Titan Technology Co., Ltd.;

[0063] Polyether-4, with a number-average molecular weight of 5000, polyether F-38, propylene glycol block polyether, boiling point 200°C, 9003-11-6, Nantong Yuanlai New Materials Co., Ltd.;

[0064] Non-polar solvent:

[0065] Acetone, with a solubility parameter of 9.8, 67-64-1, Zhongsha (Tianjin) Petrochemical Co., Ltd.;

[0066] Cyclohexanone, solubility parameter is 9.9, CAS No. 108-94-1, Liaocheng Tongda Chemical Co., Ltd.;

[0067] Methyl isobutyl ketone, solubility parameter is 8.4, CAS No. 108-10-1, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0068] Isobutyl acetate, solubility parameter is 8.3, CAS No. 110-19-0, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0069] Ethyl acetate, solubility parameter is 9.1, CAS No. 141-78-6, Tianjin Chemical Reagent Research Institute Co., Ltd.

[0070] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0071] Examples 1 to 15

[0072] Examples 1 to 15 respectively provide a solvent composition, and the component contents are shown in Table 1. The preparation method is as follows: Mix the components evenly according to Table 1 to obtain the solvent composition.

[0073] Table 1 Component contents of the solvent compositions of Examples 1 to 15 (Vol%)

[0074]

[0075]

[0076] Comparative Examples 1 to 7

[0077] Comparative Examples 1 to 7 respectively provide a solvent composition, and the component contents are shown in Table 2. The preparation method is as follows: Mix the components evenly according to Table 2 to obtain the solvent composition.

[0078] Table 2 Component contents of the solvent compositions of Comparative Examples 1 to 7 (Vol%)

[0079]

[0080]

[0081] Application Examples 1 to 24

[0082] Application Examples 1 to 24 respectively provide a ultra-high molecular weight polyethylene fiber. The preparation method is as follows:

[0083] Ultra-high molecular weight polyethylene, antioxidant, and mineral oil are dissolved in a solvent composition, where the ultra-high molecular weight polyethylene accounts for 10 wt.% of the weight of the solvent composition, the antioxidant accounts for 0.2 wt.% of the weight of the solvent composition, and the mineral oil accounts for 2 vol% of the volume of the solvent composition; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1, and the mineral oil is D80.

[0084] After obtaining the spinning fluid by mixing, the spinning fluid is added to a reaction kettle, carbon dioxide gas is introduced to expel the air in the reaction kettle, and the pressure in the reaction kettle is brought to 2 mPa; the reaction kettle is further heated to raise the temperature so that the environment in the reaction kettle reaches 180 °C and 8.0 mPa, and the spinneret valve is opened so that the spinning fluid is sprayed through the spinneret into the normal temperature and pressure environment for spinning to obtain a fiber bundle containing multiple ultra-high molecular weight polyethylene fibers.

[0085] The solvent compositions used in Application Examples 1 to 15 are the solvent compositions prepared in Examples 1 to 15 respectively, the solvent compositions used in Application Examples 16 to 22 are the solvent compositions prepared in Comparative Examples 1 to 7 respectively, and the solvent composition used in Application Examples 23 - 24 is the solvent composition prepared in Example 1.

[0086] The ultra-high molecular weight polyethylene used in Application Examples 1 to 22 is all UHMWPE-1, the ultra-high molecular weight polyethylene used in Application Example 23 is UHMWPE-2, and the ultra-high molecular weight polyethylene used in Application Example 24 is UHMWPE-3.

[0087] Performance Test

[0088] The performance of the ultra-high molecular weight polyethylene fiber bundles obtained in the above application examples was tested as follows:

[0089] (1) Spinning effect: Observe whether the spinning of the ultra-high molecular weight polyethylene fiber is continuous during the spinning process.

[0090] (2) Fiber bundle strength: Extend the fiber bundle completely until it cannot be stretched, take a 15 cm fiber bundle, and use an electronic tensile machine to test the tensile force of the fiber bundle, with a span of 100 mm and a tensile speed of 100 mm / min.

[0091] (3) Fiber bundle modulus: Extend the fiber completely until it cannot be stretched, measure the tex of the fiber bundle, and the fiber modulus = fiber strength / fiber tex.

[0092] The test results of the application examples are shown in Table 3.

[0093] Table 3 Test Results of Application Examples

[0094]

[0095] As can be seen from Table 3, when the technical solution of the present invention is used for application performance testing, the obtained ultra-high molecular weight polyethylene fiber bundle has continuous spinneret during the spinning process, and the fiber strength of the obtained fiber bundle is above 7.6 cN, and the fiber modulus is above 1.3 cN / dtex.

[0096] As can be seen from Application Examples 1 to 5, the volume percentages of the components in the solvent composition also affect the application effect. When the volume percentage of the non-polar solvent is further preferably 25-35% and the volume percentage of the composite solubilizer is 5-12%, the obtained application effect is better, the fiber strength of the fiber bundle is above 9.2 cN, and the fiber modulus is above 2.0 cN / dtex; as can be seen from Application Examples 1 and 6 to 9, the specific selection of the non-polar solvent also affects the application effect. When the non-polar solvent is further selected as acetone, the application effect is the best; as can be seen from Application Examples 1 and 10 to 15, the selection of the substances and the volume ratio in the composite solubilizer also affect the application effect.

[0097] As can be seen from Application Examples 1 and 16, when dichloromethane is used alone, the spinning process is discontinuous, and the fiber strength of the obtained product is only 6.5 cN, and the fiber modulus is only 0.9 cN / dtex; as can be seen from Application Examples 1 and 17 to 18, whether the non-polar solvent or the composite solubilizer is not added, the obtained application effect is poor, which is not much different from that of only adding dichloromethane. Compared with Example 1, the fiber strength decreases by 32.63-34.74%, and the fiber modulus decreases by 59.09-63.64%, and the spinning process is discontinuous; as can be seen from Application Examples 1 and 19 to 20, when the composite solubilizer is not used, compared with Example 1, the fiber strength decreases by 34.74-35.79%, and the fiber modulus decreases by 68.18%; as can be seen from Application Examples 1 and 21 to 22, when other solubilizers are used, the obtained application effect significantly decreases.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A solvent composition, characterized in that The following components are included in volume percentage: Non-polar solvent 20-40%, Composite solubilizer 0.5~15%, Dichloromethane balance; The composite solubilizer comprises a first solubilizer and a second solubilizer, the first solubilizer is a C1-C6 monohydric alcohol, and the second solubilizer is a polyether; The solubility parameter of the non-polar solvent is 8.3-10.

5.

2. The solvent composition according to claim 1, characterized in that The non-polar solvent includes at least one of acetone, cyclohexanone, methyl isobutyl ketone, methyl acetate, ethyl acetate, and isobutyl acetate.

3. The solvent composition according to claim 1, characterized in that: In the composite solubilizer, the first solubilizer accounts for 60-85 Vol%, and the second solubilizer accounts for 15-40 Vol%.

4. The solvent composition according to claim 1, characterized in that: The boiling point of the first solubilizing agent is ≤150°C; the boiling point of the second solubilizing agent is 200-350°C.

5. The solvent composition according to claim 1, characterized in that: The first solubilizing agent includes at least one of methanol, ethanol and propanol.

6. The solvent composition according to claim 1, characterized in that: The number average molecular weight of the polyether is 400-5000.

7. The solvent composition according to claim 1, characterized in that: The following components are included in volume percentage: Non-polar solvent 25-35%, Composite solubilizer 5-12%, Dichloromethane balance.

8. The method for preparing the solvent composition according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: uniformly mixing a non-polar solvent, a composite solubilizer and dichloromethane to obtain the obtained product.

9. Use of the solvent composition according to any one of claims 1 to 7 in the spinning of ultra-high molecular weight polyethylene fibers.

10. A spinning method for ultra-high molecular weight polyethylene fiber, characterized in that: The steps include: Dissolving ultra-high molecular weight polyethylene, antioxidant and mineral oil in a solvent and mixing them to obtain a spinning fluid; Under high temperature and high pressure conditions, the spinning fluid is ejected through the spinneret holes to a normal temperature and pressure environment to obtain the ultra-high molecular weight polyethylene fiber; The solvent is the solvent composition according to any one of claims 1 to 7.

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