Low-modulus comfortable spandex fiber and manufacturing method

Abstract

The invention discloses a low-modulus comfortable spandex fiber and a manufacturing method, the spandex fiber comprises the following components: an NCO-terminated polyurethane urea prepolymer, an ethylenediamine chain extender, an aliphatic asymmetric cyclic diamine chain extender and an end-capping reagent, and the aliphatic asymmetric cyclic diamine is selected from methyl cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 3-cyclohexanediamine and 1, 3-cyclohexanediamine. The solvent is one or a mixture of more than two of 1, 2-cyclohexanediamine and isophorone amine; wherein the aliphatic cyclic asymmetric diamine accounts for 30-70 mol% of the total amine of the chain extender; the hard chain segment in the polyurethane urea accounts for 7.5 to 12 weight percent of the polyurethane urea. According to the invention, the product component improved by the aliphatic cyclic diamine chain extender is adopted, and the produced comfortable spandex fiber has lower modulus and higher elastic recovery.

Description

Technical Field

[0001] The invention relates to the technical field of spandex fiber preparation, in particular to a low-modulus comfortable spandex fiber and a manufacturing method thereof. Background Art

[0002] The excellent ductility and resilience of spandex yarns have made them more and more widely used in clothing. The once noble fiber has entered the wardrobe of ordinary people, and its application ratio has increased year by year, from fiber MSG to one of the main components of fabric fibers. Its addition ratio in swimsuits, underwear, and sportswear even exceeds 30%. On the one hand, spandex fiber solves the problem of easy wearing and taking off of clothes. On the other hand, the shape retention and beauty provided by spandex make it irresistible once used.

[0003] In addition to appearance, the public is more concerned about the health functions of clothing. New spandex that wraps without being tight, wraps without being baggy, and has a casual texture has become the direction of efforts for manufacturers with technical reserves. To improve the comfort of spandex yarn, it is necessary to increase the elongation of spandex yarn and reduce its modulus at the same time, which can effectively relieve human body pressure and improve people's health level.

[0004] Patent CN101096778A describes the use of 2-methylpentanediamine and ethylenediamine as a combined chain extender, which results in a low modulus and a good hand feel for the spandex, but the improvement in the comfort level of the spandex is limited.

[0005] Patent CN101736435A describes the use of polyols with side methyl or ethyl groups with a molecular weight of 3000 or more to improve the softness of spandex. Currently, polyols with side groups suitable for spandex production are not easy to obtain on the market, which limits the promotion and use of this method.

[0006] CN104928798A discloses the use of terminal hydroxyl silicone oil to synthesize spandex polymer, and then blending and spinning with traditional polyether polyol-based spandex polymer, and the product has a lower modulus. Due to the low surface tension of silicone oil-based polyol, the compatibility of the traditional spandex system is low, and the system has poor spinnability.

[0007] CN108251912A discloses a method of using a chemical foaming agent to reduce the surface density of spandex to reduce the modulus of spandex and improve comfort. The chemical foaming agent used in this method is a high-polarity, low-molecular-weight compound that easily interacts with the high-polarity hard segment portion of the molecular weight of spandex, and the amount added is limited.

[0008] Patent CN101432326 discloses a two-step prepolymerization method for preparing the spandex soft segment structure, which can increase the elongation of spandex products and reduce the modulus of spandex. The two-step prepolymerization method is not suitable for direct production by existing spandex production equipment. Summary of the invention

[0009] The purpose of the present invention is to provide a low-modulus comfortable spandex fiber and a manufacturing method. Compared with ordinary products, the spandex fiber of the present invention has a lower modulus, a smaller recovery loss and improved comfort.

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

[0011] A low modulus comfortable spandex fiber, the spandex fiber comprises the following components: an NCO-terminated polyurethane urea prepolymer, an ethylenediamine chain extender, an aliphatic asymmetric cyclic diamine chain extender, and a capping agent, wherein the aliphatic cyclic asymmetric diamine is selected from one or a mixture of two or more of methylcyclohexanediamine, 1,3-cyclohexanediamine, 1,2-cyclohexanediamine, and isophordioneamine; wherein the aliphatic cyclic asymmetric diamine accounts for 30-70 mol% of the total amines of the chain extender; and the hard segment in the polyurethane urea accounts for 7.5-12wt% of the polyurethane urea.

[0012] The present invention adopts ethylenediamine and aliphatic asymmetric cyclic diamine as chain extenders, which is an original use in spandex fiber production, so as to obtain spandex fiber with low modulus and high comfort. The spandex fiber can reduce stress and improve recovery in terms of physical properties; wherein the aliphatic cyclic asymmetric diamine is selected from one or an equal mixture of two or more of methylcyclohexanediamine (HTDA), 1,3-cyclohexanediamine (1,3-CHDA), 1,2-cyclohexanediamine (1,2-CHDA), and isophordioneamine (IPDA); the hard segment is because some block copolymers have different molecular segments, some of which are composed of aromatic hydrocarbons and have greater rigidity, and are called hard segments. In the polyurethane urea of ​​the present invention, the hard segment accounts for 7.5-12wt% of the polyurethane urea; the end-capping agent of the present invention is one or a mixture of dimethylamine, diethylamine, di-n-butylamine, n-butylamine, and n-hexylamine.

[0013] As a preferred embodiment of the present invention, the aliphatic cyclic asymmetric diamine accounts for 35-65 mol% of the total amines of the chain extender.

[0014] As a preferred solution of the present invention, the hard segment accounts for 8-11 wt % of the polyurethane urea.

[0015] As a preferred solution of the present invention, the NCO-terminated polyurethane urea prepolymer is produced by the reaction of polytetramethylene glycol and diisocyanate; the diisocyanate is 4,4′-diphenylmethane diisocyanate.

[0016] As a preferred embodiment of the present invention, the number average molecular weight of the polytetrahydrofuran is 1200-2500 g / mol.

[0017] A method for manufacturing low-modulus comfortable spandex fiber comprises the following steps: weighing polytetramethylene glycol and diisocyanate; reacting the polytetramethylene glycol and diisocyanate to generate an NCO-terminated polyurethane urea prepolymer, wherein the mass percentage of NCO in the NCO-terminated polyurethane urea prepolymer is 1.8-3.0%; weighing an ethylenediamine chain extender, an aliphatic cyclic diamine, and a capping agent, wherein the molar ratio of the aliphatic cyclic diamine to the ethylenediamine is 80:20-20:80; reacting the NCO-terminated polyurethane urea prepolymer with the chain extender and the capping agent in a solvent to generate a polyurethane urea solution; adding an additive slurry to the polyurethane urea solution, mixing and maturing, to form a spinning stock solution; metering and pushing the spinning stock solution into a spinning tunnel to remove the solvent, twist, and apply oil to form spandex fiber.

[0018] The invention adopts polytetrahydrofuran diol and diisocyanate to react to generate NCO-terminated polyurethane urea prepolymer, then reacts the NCO-terminated polyurethane urea prepolymer, alicyclic diamine in a specific proportion, ethylenediamine as a chain extender, and an appropriate amount of end-capping agent in a solvent to prepare a polyurethane urea solution, adds an appropriate amount of additive slurry such as a stabilizer, an antistatic agent, etc., with the polyurethane urea solution as the main component, mixes and matures to form a spinning solution, and then spandex fibers can be prepared; the method can effectively reduce the modulus of spandex, the spandex fibers have a relatively low modulus and a relatively long elongation, and the comfort of the spandex is improved.

[0019] Compared with the prior art, the invention has the beneficial effects of using an improved product chain extender component, and producing comfortable spandex fibers with lower modulus and higher recovery. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0022] The present invention provides a technical solution:

[0023] A low modulus comfortable spandex fiber comprises the following components: an NCO-terminated polyurethane urea prepolymer, an ethylenediamine chain extender, an aliphatic asymmetric cyclic diamine chain extender, and a capping agent, wherein the aliphatic cyclic asymmetric diamine is selected from one or a mixture of two or more of methylcyclohexanediamine, 1,3-cyclohexanediamine, 1,2-cyclohexanediamine, and isophordioneamine; wherein the aliphatic cyclic asymmetric diamine accounts for 30-70 mol% of the total amines of the chain extender; and the hard segment in the polyurethane urea accounts for 7.5-12wt% of the polyurethane urea.

[0024] The end-capping agent is one of dimethylamine, diethylamine, di-n-butylamine, n-butylamine, n-hexylamine or a mixture thereof.

[0025] The aliphatic cyclic unsymmetrical diamine accounts for 35-65 mol% of the total amines of the chain extender.

[0026] The hard segments account for 8-11 wt % of the polyurethaneurea.

[0027] The NCO-terminated polyurethane urea prepolymer is prepared by reacting polytetramethylene glycol with a diisocyanate; the diisocyanate is 4,4'-diphenylmethane diisocyanate.

[0028] The number average molecular weight of polytetrahydrofuran is 1200-2500 g / mol.

[0029] A method for producing low modulus comfortable spandex fiber comprises the following steps:

[0030] Weigh polytetrahydrofuran diol and diisocyanate;

[0031] Allowing polytetramethylene glycol and diisocyanate to react to generate an NCO-terminated polyurethane urea prepolymer, wherein the mass percentage of NCO in the NCO-terminated polyurethane urea prepolymer is 1.8-3.0%;

[0032] Weigh ethylenediamine chain extender, aliphatic cyclic diamine, and end-capping agent, wherein the molar ratio of aliphatic cyclic diamine to ethylenediamine is 80:20-20:80;

[0033] The NCO-terminated polyurethane urea prepolymer is reacted with a chain extender and a capping agent in a solvent to generate a polyurethane urea solution;

[0034] Adding the additive slurry into the polyurethane urea solution and mixing and aging to form a spinning solution;

[0035] The spinning solution is metered and pushed into the spinning tunnel to remove the solvent, twist and oil the fibers to form spandex fibers.

[0036] Specific implementation process;

[0037] Example 1

[0038] Step 1: Preparation of spandex prepolymer

[0039] 3.000 kg of polytetrahydrofuran diol PTHF with a number average molecular weight of 1800 g / mol and 0.704 kg of diisocyanate MDI produced by BASF were reacted at 90° C. for 90 min to generate an NCO-terminated polyurethane urea prepolymer with an NCO% of 2.60%. The prepolymer was cooled to below 50° C. and the NCO-terminated polyurethane urea prepolymer was dissolved in cold dimethylacetamide DMAC to obtain an NCO-terminated polyurethane urea prepolymer DMAC solution.

[0040] Step 2: Preparation of spandex polymer

[0041] 1) dissolving 0.0401 kg of ethylenediamine, 0.0758 kg of isophordioneamine (IPDA), and 0.0118 kg of diethylamine in a solvent DMAC to form a chain extender mixture solution having a mass percent concentration of 7.00%;

[0042] 2) adding a chain extender mixture solution to the DMAC solution of the spandex prepolymer and stirring, wherein the molar ratio of the amine equivalent to the isocyanate group is 1.03:1, and reacting to form a polyurethane urea spandex solution with a mass percentage concentration of 36%.

[0043] Step 3: Preparation of spandex spinning solution

[0044] 1) stirring an antioxidant, an anti-ultraviolet agent and a lubricant with a stirrer and a grinder to prepare a uniformly dispersed additive slurry, wherein the mass percentage concentration of the prepared additive slurry is 36%;

[0046] 2) Adding the additive slurry to the polyurethane urea spandex solution in step 2; the solid content of the additive slurry relative to the mass of the polyurethane urea is 1% antioxidant, 1% anti-ultraviolet agent, and 0.2% lubricant.

[0047] 3) The polyurethane urea spandex solution was stored at 45°C for 40 hours, and after being fully matured,

[0048] A spinning solution with a viscosity of 4000 poise was obtained.

[0049] Step 4: Spinning spandex yarn

[0050] The spinning solution prepared in the third step is pushed through a spinning metering pump, wound by rollers, and drawn to form a winding bobbin.

[0051] Embodiment 2:

[0052] Step 1: Preparation of spandex prepolymer

[0053] 3.000 kg of polytetrahydrofuran diol PTHF with a number average molecular weight of 1800 g / mol and 0.634 kg of diisocyanate MDI produced by BASF are reacted at 90° C. for 90 min to generate an NCO-terminated polyurethane urea prepolymer with an NCO% of 2.00%. The NCO-terminated polyurethane urea prepolymer is cooled to below 50° C. and dissolved in cold dimethylacetamide DMAC to obtain an NCO-terminated polyurethane urea prepolymer DMAC solution.

[0054] Step 2: Preparation of spandex polymer

[0055] 1) dissolving 0.0354 kg of ethylenediamine, 0.0323 kg of methylcyclohexanediamine (MCDA), and 0.00891 kg of diethylamine in a solvent DMAC to form a chain extender mixture solution having a mass percent concentration of 7.00%;

[0056] 2) Same as 2) in the second step of Example 1.

[0057] Step 3: Preparation of spandex spinning solution

[0058] Same as the third step of Example 1.

[0059] Step 4: Spinning spandex yarn

[0060] Same as the fourth step of Example 1.

[0061] Embodiment 3:

[0062] Step 1: Preparation of spandex prepolymer

[0063] 3.000 kg of polytetrahydrofuran diol PTHF with a number average molecular weight of 2000 g / mol and 0.634 kg of diisocyanate MDI produced by BASF are reacted at 90° C. for 90 min to generate an NCO-terminated polyurethane urea prepolymer with an NCO% of 2.40%. The NCO-terminated polyurethane urea prepolymer is cooled to below 50° C. and dissolved in cold dimethylacetamide DMAC to obtain an NCO-terminated polyurethane urea prepolymer DMAC solution.

[0064] Step 2: Preparation of spandex polymer

[0065] 1) 0.0362 kg of ethylenediamine, 0.0459 kg of 1,2-cyclohexanediamine (1,2-CHDA), and 0.0106 kg of diethylamine were dissolved in a solvent DMAC to form a chain extender mixture solution with a mass percent concentration of 7.00%.

[0066] 2) Same as 2) in the second step of Example 1.

[0067] Step 3: Preparation of spandex spinning solution

[0068] Same as the third step of Example 1.

[0069] Step 4: Spinning spandex yarn

[0070] Same as the fourth step of Example 1.

[0071] Embodiment 4:

[0072] Step 1: Preparation of spandex prepolymer

[0073] Same as the first step in Example 3.

[0074] Step 2: Preparation of spandex polymer

[0075] 1) The same as the second step in Example 3, except that 1,2-cyclohexyldiamine (1,2-CHDA) was replaced with 1,3-cyclohexyldiamine (1,3-CHDA).

[0076] 2) Same as 2) in the second step of Example 1.

[0077] Step 3: Preparation of spandex spinning solution

[0078] Same as the third step of Example 1.

[0079] Step 4: Spinning spandex yarn

[0080] Same as the fourth step of Example 1.

[0081] Comparative Example 1

[0082] Step 1: Preparation of spandex prepolymer

[0083] 3.000 kg of polytetrahydrofuran diol PTHF with a number average molecular weight of 2000 g / mol and 0.638 kg of diisocyanate MDI produced by BASF were reacted at 90°C for 90 minutes to generate a prepolymer with an NCO% of 2.43%. The prepolymer was cooled to below 50°C and dissolved in cold dimethylacetamide DMAC to obtain a prepolymer DMAC solution.

[0084] Step 2: Preparation of spandex polymer

[0085] 1) 0.0490 kg of ethylenediamine, 0.0151 kg of 1.2-propylenediamine (PDA), and 0.0108 kg of diethylamine were dissolved in a solvent, DMAC, to form a chain extender mixture solution having a mass percent concentration of 7.00%.

[0086] 2) Same as 2) in the second step of Example 1.

[0087] Step 3: Preparation of spandex spinning solution

[0088] Same as the third step of Example 1.

[0089] Step 4: Spinning spandex yarn

[0090] Same as the fourth step of Example 1.

[0091] In a specific embodiment of the present invention, the physical properties of the obtained spandex fiber are tested under the following test conditions:

[0092] 1) Elongation at break and SS300

[0093] A 5 cm sample was stretched using a tensile testing machine (manufactured by Instron Corp) at 25° C., 65% relative humidity and a speed of 50 cm / min, and the elongation at break DE and the stress at 300% elongation SS300 were measured.

[0094] 2) Elastic recovery rate

[0095] The sample was marked at intervals of 10 cm, tension was applied to stretch it 300%, and it was reciprocated and stretched 5 times, and then the preload tension was maintained for 60 seconds, and the length of the recovered sample was measured.

[0096] Elastic rebound (%) = [(L1-L2) / (L1-L0] x 100

[0097] Where L0 is the length between the marked portions of the sample, L1 is the length of the sample when stretched 300%, and L2 is the length of the sample after maintaining the preload tension for 60 seconds.

[0098]

[0099] In the comparative example, ethylenediamine, 1.2-propylenediamine PDA, and diethylamine were dissolved in a solvent DMAC to form a chain extender mixture solution, wherein diethylamine was used as a capping agent. Other raw materials and manufacturing methods were basically the same as those of Examples 1-4, but differences occurred in physical properties. The main difference was that the comparative example used 1.2-propylenediamine PDA, which is a type of chain extender in spandex and will change the group structure of the spandex molecular chain, greatly affecting the performance of spandex.

[0100] The present invention adopts ethylenediamine and aliphatic asymmetric cyclic diamine as chain extenders. The aliphatic asymmetric cyclic diamine is designated as one of methylcyclohexanediamine (HTDA), 1,3-cyclohexanediamine (1,3-CHDA), 1,2-cyclohexanediamine (1,2-CHDA), and isophordioneamine (IPDA). It is used in the production of spandex fiber for original purpose, so that low modulus and high comfort spandex fiber can be obtained. The spandex fiber can reduce stress and improve recovery in terms of physical properties. It can be seen from the test data that the elongation at break of the products of Examples 1 to 4 of the present invention are all lower than that of the comparative product, the elongation length of the SS300 sample is lower than that of the comparative product, and the elastic recovery rate is higher than that of the comparative product.

[0101] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low modulus comfortable spandex fiber, characterized in that: The spandex fiber comprises the following components: NCO-terminated polyurethane urea prepolymer, ethylenediamine chain extender, aliphatic asymmetric cyclic diamine chain extender, and a capping agent, wherein the aliphatic cyclic asymmetric diamine is selected from one or a mixture of two or more of methylcyclohexanediamine, 1,3-cyclohexanediamine, 1,2-cyclohexanediamine, and isophordioneamine; Among them, the aliphatic cyclic asymmetric diamine accounts for 30-70 mol% of the total amines of the chain extender; The hard segment in the polyurethane urea accounts for 7.5-12wt% of the polyurethane urea.

2. A low modulus comfortable spandex fiber according to claim 1, characterized in that: The aliphatic cyclic asymmetric diamine accounts for 35-65 mol% of the total amines of the chain extender.

3. A low modulus comfortable spandex fiber according to claim 1, characterized in that: The hard segments account for 8-11 wt % of the polyurethane urea.

4. A low modulus comfortable spandex fiber according to claim 1, characterized in that: The NCO-terminated polyurethane urea prepolymer is produced by the reaction of polytetrahydrofuran diol and diisocyanate; The diisocyanate is 4,4'-diphenylmethane diisocyanate.

5. A low modulus comfortable spandex fiber according to claim 4, characterized in that: The number average molecular weight of the polytetrahydrofuran is 1200-2500 g / mol.

6. A method for producing a low modulus comfortable spandex fiber according to any one of claims 1 to 5, characterized in that: The steps include: Weigh polytetrahydrofuran diol and diisocyanate; Allowing the polytetramethylene glycol and diisocyanate to react to generate an NCO-terminated polyurethane urea prepolymer, wherein the mass percentage of NCO in the NCO-terminated polyurethane urea prepolymer is 1.8-3.0%; Weigh ethylenediamine chain extender, aliphatic cyclic diamine, and end-capping agent, wherein the molar ratio of aliphatic cyclic diamine to ethylenediamine is 80:20-20:80; Allowing the NCO-terminated polyurethane urea prepolymer to react with a chain extender and a capping agent in a solvent to generate a polyurethane urea solution; Adding the additive slurry into the polyurethane urea solution, mixing and aging to form a spinning solution; The spinning solution is metered and pushed into the spinning tunnel to remove the solvent, twist and oil the fibers to form spandex fibers.

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