A kind of high cohesive force spandex multifilament and production method thereof

Abstract

The invention provides a high-cohesion spandex multifilament and a production method thereof. Solvent retaining agents are added in the prepolymerization step or the auxiliary agent adding step in the spandex multifilament production process. Since these substances have strong binding ability with polar solvents such as DMAc and DMF, the volatilization rate of the solvent in the spinning process is slowed down, so that a certain amount of solvent is still retained on the spandex monofilament during the false twisting process, and then the surface of the spandex monofilament has greater viscosity during the false twisting process, thereby increasing the bonding ability between the spandex monofilaments and increasing the cohesion between the monofilaments in the prepared spandex multifilament.

Description

Technical Field

[0001] The invention relates to a spandex multifilament and a production method thereof, in particular to a spandex multifilament with high cohesion force that is easy to false-twist and a production method thereof. Background Art

[0002] Spandex is the abbreviation of polyurethane (polyurethane) fiber, which is a highly elastic and elongated synthetic fiber. Spandex multifilament composed of multiple spandex monofilaments has a wide range of applications in fabrics and clothing. For example, 30-40 denier multifilaments can be used for weft knitting and warp knitting, 40-70 denier multifilaments can be used for jeans and ready-made clothes, 120-140 denier multifilaments can be used for socks, waists, and cuffs, 210-420 denier multifilaments can be used for warp knitting meshes and laces, and multifilaments greater than 420 deniers can be used for diapers, webbing, elastic bands, thick stockings and other products.

[0003] Spandex multifilaments are usually produced by dry spinning. In the spinning tunnel, the prepolymer solution is ejected from the spinneret to form multiple thin streams of stock solution. The hot gas in the tunnel takes away the solvent in the thin streams of stock solution, causing the thin streams of stock solution to solidify to form spandex monofilaments. Multiple spandex monofilaments are attached to each other in the tunnel through false twisting to form a coarse-denier spandex multifilament.

[0004] The individual filaments of spandex multifilaments should have a certain cohesion to avoid the multifilaments from splitting during use. However, in the actual production process of multifilaments, due to electrostatic repulsion or too small contact surface between the filaments, the false twisting effect may be poor, resulting in poor cohesion between the individual filaments in the multifilaments, easy splitting of the spandex multifilaments during use, and adverse effects on the overall mechanical properties of the spandex multifilaments. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a high-cohesion spandex multifilament and a production method thereof, and the specific scheme is as follows:

[0006] A high-cohesion spandex multifilament yarn, characterized in that the spandex multifilament yarn comprises a plurality of spandex monofilaments, and the spandex monofilaments contain a solvent retaining agent.

[0007] Optionally, the spandex monofilament has a denier of 10-20 deniers.

[0008] Optionally, the solvent retaining agent is one or more of succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt, and pyrrolidine salt.

[0009] The preparation method of the high cohesive force spandex multifilament is as follows:

[0010] A method for producing high-cohesion spandex multifilament yarn comprises the following steps:

[0011] 1) using a diisocyanate raw material to end-cap a diol raw material to prepare a prepolymer;

[0012] 2) using a polar solvent to dissolve the prepolymer;

[0013] 3) chain extension using a mixed solution of a chain extender and a terminator;

[0014] 4) adding an auxiliary agent to obtain a spinning solution;

[0015] 5) Dry spinning is adopted, and before winding, the single filaments are cohesively connected by a false twisting device to obtain spandex multifilaments;

[0016] The invention is characterized in that the auxiliary agent comprises a solvent retaining agent, and the solvent retaining agent accounts for 0.03%-0.5% of the mass of the spinning solution.

[0017] Optionally, the solvent retaining agent is one or more of succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt, and pyrrolidine salt.

[0018] Alternatively, a method for producing high-cohesive spandex multifilament comprises the following steps:

[0019] 1) using a diisocyanate raw material to end-cap a diol raw material to prepare a prepolymer;

[0020] 2) using a polar solvent to dissolve the prepolymer;

[0021] 3) chain extension using a mixed solution of a chain extender and a terminator;

[0022] 4) adding an auxiliary agent to obtain a spinning solution;

[0023] 5) Dry spinning is adopted, and before winding, the single filaments are cohesively connected by a false twisting device to obtain spandex multifilaments;

[0024] Characterized in that, in the step 1), a solvent retaining agent is further added, and the solvent retaining agent accounts for 0.1%-1.5% of the prepolymer mass.

[0025] Optionally, the solvent retaining agent is one or more of imidazole salts, quaternary ammonium salts, and quaternary phosphonium salts.

[0026] Optionally, the polar solvent is at least one of N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAC).

[0027] The invention provides the use of succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt, pyrrolidine salt and the like as solvent retaining agent for spandex spinning stock solution.

[0028] Optionally, the chain extender is a diamine having 2 to 30 carbon atoms, and the terminator is a monoamine having 2 to 20 carbon atoms.

[0029] Optionally, the wind speed of the dry spinning in step 5) is 10-20 Nm 3 / min, the gas temperature is above 240℃.

[0030] Optionally, in step 5), the fineness of the monofilament is 10-20 denier.

[0031] Optionally, the multifilament in step 5) comprises at least two monofilaments.

[0032] Optionally, the false twisting device is at least one of a rubber ring type false twister, an air flow false twister, a friction disk type false twister, and a rotor type false twister.

[0033] Beneficial effects:

[0034] The invention adds succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt, pyrrolidine salt and the like as solvent retaining agents during the spinning process of spandex. Since these substances have strong binding ability with polar solvents such as DMAc and DMF, the volatilization speed of the solvent during the spinning process is delayed, so that a certain amount of solvent is still retained on the spandex monofilament during the false twisting process, and further the surface of the spandex monofilament has greater viscosity during the false twisting process, thereby increasing the bonding ability between the spandex monofilaments and increasing the cohesion between the spandex monofilaments. DETAILED DESCRIPTION

[0035] Conventional spandex multifilaments are usually made by false twisting multiple spandex monofilaments. However, after false twisting, the ordinary monofilaments may have insufficient cohesion between the monofilaments, which can easily cause splitting and affect the mechanical properties and subsequent use of the spandex multifilaments.

[0036] To this end, the present invention provides a high-cohesion spandex multifilament and a production method of the spandex multifilament, which effectively increases the cohesion performance between the monofilaments in the spandex multifilament. The specific scheme is as follows:

[0037] A high-cohesion spandex multifilament yarn, characterized in that the spandex multifilament yarn comprises a plurality of spandex monofilaments, and the spandex monofilaments contain a solvent retaining agent.

[0038] The solvent retaining agent is one or more of succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt and pyrrolidine salt.

[0039] Solvent retaining agent described in the present invention refers to a class of substances that can interact with solvent and slow down the solvent volatilization speed, for example, can be substances such as succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt, pyrrolidinium salt. Because the above-mentioned substances have stronger binding ability with polar solvents such as DMAc and DMF, and themselves are hardly volatile in the environment of the spinning tunnel, so that in the spinning process, these substances can delay the volatilization of solvent. Because the spandex monofilaments have just begun to approach each other in the tunnel for false twisting compared to conventional spandex production, the spandex monofilaments added with solvent retaining agent still retain a certain amount of solvent when the monofilaments contact each other during the false twisting process, the solvent that has not been fully volatilized makes the spandex monofilament surface more sticky, and the fitting between the monofilaments can be more closely during false twisting, and the viscosity between each other also makes it more difficult to separate between the monofilaments, thereby enhancing the combination between the monofilaments after the solvent is fully volatilized, thereby the cohesive force between the monofilaments after false twisting can be increased. In addition, the above-mentioned solvent retaining agent also has a certain water absorption capacity, so that the produced spandex multifilament can still absorb a certain amount of water during storage. The bonding force between the moistened spandex monofilaments will be greater, and it can also play a role in reducing the electrical resistance of the spandex. The low-resistance spandex yarn can export the electric charge on the surface of the spandex, and to a certain extent, it can also increase the bonding force between the spandex monofilaments.

[0040] Optionally, the monofilament fineness is 10-20 denier.

[0041] When the denier of spandex monofilament is too large, due to the presence of solvent retaining agent, the solvent in the fiber is more difficult to evaporate, so that the fiber still retains excess solvent when it leaves the channel, which is not conducive to the mechanical properties of the fiber and solvent recovery; when the denier of spandex monofilament is too small, the monofilament is too thin and the tension is too low, and the fiber has poor spinnability.

[0042] The production method of the above spandex multifilament comprises the following steps:

[0043] 1) using a diisocyanate raw material to end-cap a diol raw material to prepare a prepolymer;

[0044] 2) using a polar solvent to dissolve the prepolymer;

[0045] 3) chain extension using a mixed solution of a chain extender and a terminator;

[0046] 4) adding an auxiliary agent to obtain a spinning solution;

[0047] 5) Dry spinning is adopted, and before winding, the single filaments are cohesively connected by a false twisting device to obtain spandex multifilaments;

[0048] The invention is characterized in that the auxiliary agent comprises a solvent retaining agent, and the solvent retaining agent accounts for 0.03%-0.5% of the mass of the spinning solution.

[0049] In the method provided by the present invention, in addition to the conventional additives such as anti-ultraviolet agent, antioxidant, lubricant, matting agent, etc., the additive further includes a solvent retaining agent, and the amount of the solvent additive added accounts for 0.03%-0.5% of the mass of the spinning solution, where the mass of the spinning solution refers to the mass of the spinning solution after the additive is added. If the amount of solvent retaining agent added is too large, the fiber will still have excess solvent when it leaves the tunnel, which is not conducive to the mechanical properties of the fiber and solvent recovery. If the amount of solvent retaining agent added is too small, it will not have the effect of increasing the cohesion between the spandex monofilaments.

[0050] In the present invention, the diisocyanate raw material may be one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isomers thereof.

[0051] The diol raw material can be a conventional polyether diol or polyester diol. The polyether diol can be polytetramethylene glycol, polypropylene glycol, N-methyldiethanolamine, etc. The polyester diol can be a polyester diol obtained by copolymerizing small molecular diols such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, neopentyl glycol, etc. with dicarboxylic acids such as succinic acid, adipic acid, and aromatic dibasic acids. In the present invention, the diol raw material is preferably polytetramethylene glycol (PTMG) with a molecular weight of 1000-3000.

[0052] The chain extender can be an amine or alcohol chain extender, wherein the amine chain extender can be a diamine with a carbon number of 2 to 30, for example, it can be selected from one or more of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, methylpentylenediamine, methylpropylenediamine, hexylenediamine, triethylenediamine, benzylenediamine, phenylenediamine, diaminocyclohexane, hexamethylenediamine, and dopamine; the alcohol chain extender can be one or more of common chain extenders such as ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propylene glycol, and 1,4-dihydroxymethylcyclohexane.

[0053] The chain terminator can be a monoamine having 2 to 20 carbon atoms, and can be selected from one or more of ethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine or ethanolamine.

[0054] The solvent retaining agent is one or more of succinate, barium sulfate, imidazole salt, quaternary ammonium salt, quaternary phosphonium salt, piperidine salt and pyrrolidine salt.

[0055] The polar solvent is at least one of N,N-dimethylformamide and N,N-dimethylacetamide.

[0056] N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAc) are commonly used solvents in spandex dry spinning. Compared with polymers, small molecule solvent retainers are non-volatile and have strong interactions with solvents. Volatile solvents require higher heat energy or longer time to break free from the interaction between small molecule solvent retainers and solvents. The contact between the monofilaments has already occurred in the tunnel. Due to the addition of solvent retainers, the monofilaments still retain more solvent when they contact each other, making the monofilament surfaces more sticky and the contact-type fits each other more closely. In addition, when the amount of solvent retainers added meets the requirements, the existing tunnel length is also sufficient to evaporate the solvent in the fiber. Without changing the raw materials, equipment and processes of the existing spandex multifilament production, the spandex monofilaments in the false twisting process can be made more sticky, thereby increasing the cohesion of the spandex multifilaments after false twisting.

[0057] The wind speed of the dry spinning in step 5) is 10-20 Nm 3 / min, the gas temperature is above 240℃.

[0058] In the step 5), the fineness of the monofilament is 10-20 deniers.

[0059] The multifilament in step 5) comprises at least two monofilaments.

[0060] The false twisting device is at least one of a friction disc false twister, an air flow false twister, an apron false twister and a rotor false twister.

[0061] Common false twisting equipment can be used for the production of spandex multifilament in this scheme.

[0062] Alternatively, the method for producing spandex multifilament is characterized in that the solvent retaining agent is added in step 1) instead of being added together with the auxiliary agent, and the solvent retaining agent accounts for 0.1-1.5% of the mass of the prepolymer.

[0063] At this time, the solvent retaining agent is one or more of imidazole salts, quaternary ammonium salts, and quaternary phosphonium salts.

[0064] Because isocyanate is prone to side reactions under alkaline conditions, the solvent retaining agent added in the prepolymerization stage should avoid using alkaline solvents, so acidic or neutral additives should be used, such as imidazole salts, quaternary ammonium salts, quaternary phosphonium salts and other weak base strong acid solvent retaining agents. The other process parameters mentioned above remain unchanged.

[0065] The present invention is described in more detail below by way of examples, wherein the testing methods of the parameters involved are specifically as follows:

[0066] The spandex cohesion is tested according to the test method provided in the Textile Industry Standard of the People's Republic of China FZ / T 50039-2018, Test Method for Cohesion Performance of Spandex Filaments.

[0067] Example 1

[0068] 100kg of polytetrahydrofuran PTMG2000 was added to a reactor that had been thermostated to 45°C, and stirring was started at a stirring speed of 150rpm. 22.2kg of diphenylmethane diisocyanate was added, and the temperature was raised to 90°C after stirring for 5min, and it was reacted at 90°C for 2h to obtain an isocyanate-terminated prepolymer. The prepolymer was cooled to 50°C, 155.5kg of DMAc was used to dissolve the prepolymer, and then an amine solution containing 2.26kg of ethylenediamine (EDA) and 0.28kg of diethylamine (DEA) with a concentration of 3.2% was added, and the stirring speed was increased to 300rpm to carry out a chain extension reaction. After the chain extension reaction was completed, an auxiliary agent was added, which included an antioxidant and a dyeing auxiliary, and 0.7kg of 1-allyl-3-vinyl imidazole bromide was added as a solvent retainer. After adding the auxiliary agent, the spinning solution was obtained by aging for 30h. The above stock solution was subjected to dry spinning, and the single filaments were entangled using an air flow false twister to obtain a spandex multifilament with a single filament fineness of 15 denier and a total denier of 45D.

[0069] According to the test method provided in FZ / T 50039-2018, "Test Method for Cohesion Performance of Spandex Filaments", the average cohesion force of spandex multifilament was measured to be 0.92 cN.

[0070] Example 2

[0071] 100kg of polytetrahydrofuran PTMG2000 was added to a reactor that had been kept at a constant temperature of 45°C, and stirring was started at a stirring speed of 150rpm. 22.2kg of diphenylmethane diisocyanate was added, and the temperature was raised to 90°C after stirring for 5min, and it was reacted at 90°C for 2h to obtain an isocyanate-terminated prepolymer. The prepolymer was cooled to 50°C, 155.5kg of DMAc was used to dissolve the prepolymer, and then an amine solution containing 2.26kg of ethylenediamine (EDA) and 0.28kg of diethylamine (DEA) with a concentration of 3.2% was added, and the stirring speed was increased to 300rpm to carry out a chain extension reaction. After the chain extension reaction was completed, an auxiliary agent was added, which included an antioxidant and a dyeing auxiliary, and 0.53kg of 1-ethyl-3-methylimidazolium hydrogen sulfate was added as a solvent retainer. After adding the auxiliary agent, the spinning solution was obtained by aging for 30h. The above stock solution was subjected to dry spinning, and the single filaments were entangled using an air flow false twister to obtain a spandex multifilament with a single filament fineness of 15 denier and a total denier of 45D.

[0072] According to the test method provided in FZ / T 50039-2018, "Test Method for Cohesion Performance of Spandex Filaments", the average cohesion force of spandex multifilament was measured to be 0.86 cN.

[0073] Example 3

[0074] 100kg of polytetrahydrofuran PTMG2000 and 0.82kg of 1-hexyl-23-dimethylimidazole tetrafluoroborate as solvent retaining agent are added to the reactor which has been kept at a constant temperature of 45°C, and stirring is started at a stirring speed of 150rpm. 22.2kg of diphenylmethane diisocyanate is added, and the temperature is raised to 90°C after stirring for 5min, and it is reacted at 90°C for 2h to obtain an isocyanate-terminated prepolymer. The prepolymer is cooled to 50°C, 155.5kg of DMAc is used to dissolve the prepolymer, and then an amine solution with a concentration of 3.2% containing 2.26kg of ethylenediamine (EDA) and 0.28kg of diethylamine (DEA) is added, and the stirring speed is increased to 300rpm to carry out a chain extension reaction. After the chain extension reaction is completed, antioxidants, dyeing aids and other auxiliaries are added, and the spinning solution is obtained after aging for 30h. The above stock solution was subjected to dry spinning, and the single filaments were entangled using an air flow false twister to obtain a spandex multifilament with a single filament fineness of 15 denier and a total denier of 45D.

[0075] According to the test method provided in FZ / T 50039-2018, Test Method for Cohesion Performance of Spandex Filaments, the average cohesion force of spandex multifilament was measured to be 0.98 cN.

[0076] Comparative Example 1

[0077] Add 100kg of polytetrahydrofuran PTMG2000 to a reactor that has been kept at a constant temperature of 45°C, start stirring, and stir at a speed of 150rpm. Add 22.2kg of diphenylmethane diisocyanate, stir for 5min, then heat to 90°C, and react at 90°C for 2h to obtain an isocyanate-terminated prepolymer. Cool the prepolymer to 50°C, use 155.5kgDMAc to dissolve the prepolymer, then add an amine solution containing 2.26kg of ethylenediamine (EDA) and 0.28kg of diethylamine (DEA) with a concentration of 3.2%, increase the stirring speed to 300rpm, and carry out a chain extension reaction. After the chain extension reaction is completed, add auxiliaries such as antioxidants and dyeing agents, and ripen for 30h to obtain a spinning solution. The above solution is dry-spun, and an air flow false twister is used to make the monofilaments cohere to obtain a spandex multifilament with a monofilament fineness of 15 denier and a total denier of 45D.

[0078] According to the test method provided in FZ / T 50039-2018, Test Method for Cohesion Performance of Spandex Filaments, the average cohesion force of spandex multifilament was measured to be 0.56 cN.

[0079] By comparing the cohesive forces measured in Examples 1-3 with those in Comparative Example 1, it can be seen that the scheme of the present invention effectively improves the cohesive force of the prepared spandex multifilament.

Claims

1. A high cohesive force spandex multifilament, characterized in that: The spandex multifilament comprises a plurality of spandex monofilaments, and the spandex monofilaments contain a solvent retaining agent; The production method of high-cohesion spandex multifilament comprises the following steps: 1) using a diisocyanate raw material to end-cap a diol raw material to prepare a prepolymer; 2) using a polar solvent to dissolve the prepolymer; 3) chain extension using a mixed solution of a chain extender and a terminator; 4) adding an auxiliary agent to obtain a spinning solution; 5) Dry spinning is adopted, and before winding, the single filaments are cohesively twisted to obtain spandex multifilaments; Wherein, the auxiliary agent includes a solvent retaining agent, the solvent retaining agent accounts for 0.03%-0.5% of the mass of the spinning solution, and the solvent retaining agent is one or more of barium sulfate, 1-allyl-3-vinyl imidazolium bromide, 1-ethyl-3-methylimidazolium hydrogen sulfate, and 1-hexyl-23-dimethylimidazolium tetrafluoroborate; or, In the step 1), a solvent retaining agent is further added, and the solvent retaining agent accounts for 0.1%-1.5% of the prepolymer mass. The solvent retaining agent is one or more of 1-allyl-3-vinyl imidazolium bromide, 1-ethyl-3-methylimidazolium hydrogen sulfate, and 1-hexyl-23-dimethylimidazolium tetrafluoroborate.

2. The spandex multifilament according to claim 1, characterized in that: The spandex monofilament has a fineness of 10-20 deniers.

3. A method for producing high-cohesion spandex multifilament, comprising the following steps: 1) using a diisocyanate raw material to end-cap a diol raw material to prepare a prepolymer; 2) using a polar solvent to dissolve the prepolymer; 3) chain extension using a mixed solution of a chain extender and a terminator; 4) adding an auxiliary agent to obtain a spinning solution; 5) Dry spinning is adopted, and before winding, the single filaments are cohesively connected by a false twisting device to obtain spandex multifilaments; It is characterized in that The auxiliary agent includes a solvent retaining agent, and the solvent retaining agent accounts for 0.03%-0.5% of the mass of the spinning solution; The solvent retaining agent is one or more of barium sulfate, 1-allyl-3-vinyl imidazolium bromide, 1-ethyl-3-methylimidazolium hydrogen sulfate, and 1-hexyl-23-dimethylimidazolium tetrafluoroborate.

4. A method for producing high-cohesion spandex multifilament, comprising the following steps: 1) using a diisocyanate raw material to end-cap a diol raw material to prepare a prepolymer; 2) using a polar solvent to dissolve the prepolymer; 3) chain extension using a mixed solution of a chain extender and a terminator; 4) adding an auxiliary agent to obtain a spinning solution; 5) Dry spinning is adopted, and before winding, the single filaments are cohesively twisted to obtain spandex multifilaments; It is characterized in that In the step 1), a solvent retaining agent is also added, and the solvent retaining agent accounts for 0.1%-1.5% of the prepolymer mass; The solvent retaining agent is one or more of 1-allyl-3-vinyl imidazolium bromide, 1-ethyl-3-methylimidazolium hydrogen sulfate, and 1-hexyl-23-dimethylimidazolium tetrafluoroborate.

5. The production method according to any one of claims 3 to 4, characterized in that: The polar solvent is at least one of N,N-dimethylformamide and N,N-dimethylacetamide.

6. The production method according to any one of claims 3 to 4, characterized in that: The wind speed of the dry spinning in step 5) is 10-20 Nm 3 / min, the gas temperature is above 240℃.

7. The production method according to any one of claims 3 to 4, characterized in that: The false twisting device is at least one of an apron type false twister, an air flow false twister, a friction disk type false twister and a rotor type false twister.