JP2902719B2 - Method for producing polyurethane elastic yarn - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a polyurethane elastic yarn by a melt spinning method. More specifically, when producing a polyurethane elastic yarn by melt spinning, it prevents sticking between the yarns on the spinning bobbin, improves the unwinding property of the yarn in the subsequent processing step, and moderately slips the yarn. The present invention relates to a method for preventing the spinning bobbin and the like from falling off and collapsing, and stabilizing the operability in the spinning and subsequent processing steps.

(Prior Art) As a method for producing a polyurethane elastic yarn, a melt spinning method, a dry spinning method, a wet spinning method, and the like have been conventionally performed, and recently, in order to improve the stretchability and heat resistance of a urethane yarn. A method of mixing and spinning a prepolymer having an active isocyanate group, a so-called cross-linking agent, is often used. In any of these methods, when the fiber is wound at the time of spinning, the fibers adhere to each other, so that it is difficult to pull out the yarn due to the resistance of the adhesive when unwinding the yarn from the bobbin and pulling it out in the subsequent process. Thread breakage occurs, causing a state where smooth operation cannot be performed. In particular, in the cross-linking agent mixed spinning method in which a large amount of active isocyanate groups are present, this sticking is remarkable,
Usually, if the oil agent is applied, a material that can draw out the yarn in the subsequent process cannot be obtained.

The method of preventing the sticking includes a method of applying solid fine particles such as talc, silica, and colloidal alumina to the fiber as an aqueous or oily slurry, and a method of dispersing a metal salt powder of a higher fatty acid in water or mineral oil (Japanese Patent Publication No. Sho 41-41). No. 286,
JP-B-40-5557), a method of dispersing a room temperature solid wax such as a higher aliphatic carboxylic acid, a higher aliphatic alcohol, paraffin, polyethylene or the like in an oil agent mainly composed of mineral oil (JP-B-43-272, JP-B-43) −9955, Japanese Patent Publication No. 44
JP-A-8907), a method of using polyalkylene oxide-modified silicon as an anti-stick agent as a liquid material at room temperature (JP-B-45-40719, JP-A-48-19893, JP-A-48-19893)
Many methods have been proposed, such as a method of dissolving cyclic amylcycloxane in dimethylsiloxane (JP-B-39-24858).

However, these anti-sticking agents mainly based on the release effect have no effect on the sticking due to a chemical reaction by an isocyanate group described later, and it cannot be said that the method is sufficiently satisfactory.

Adhesion between yarns in the spinning of polyurethane elastic yarns is caused not only by the rubbery tackiness of polyurethane but also by a surface chemical reaction between the yarns due to active isocyanate groups on the yarn surface, which is generally called self-adhesion. Formation of an allohanate bond and other chemical bonds). In this self-adhesion action, as the number of isocyanate groups present on the polymer surface during spinning increases, the chemical reaction on the yarn surface progresses, and a firm adhesion is formed. Immediately after spinning, even on a bobbin capable of unwinding the yarn, the self-adhesion between the yarns progresses after several days, and the unwinding of the yarn becomes impossible,
In an extreme case, the yarn wound on the winding bobbin may adhere to a plate shape. In particular, this sticking phenomenon is intense when producing a polyurethane elastic yarn by melt spinning, and the tendency is remarkable in the method of mixing and spinning the active both terminal diisocyanate prepolymer during spinning as a cross-linking agent. The agent alone cannot sufficiently prevent sticking.

In order to prevent sticking due to the chemical reaction of the isocyanate group, it is necessary to deactivate the isocyanate group, and a method using a deactivator having an active hydrogen group has been proposed. As the method, a method of applying a mineral oil in which a monoamine is dissolved at the time of spinning (Japanese Patent Publication No. 46-16312) and an oil agent containing a diamine (Japanese Patent Application Laid-Open No. 58-132170) have already been proposed. However, these methods are effective for deactivating the isocyanate group, and excellent spin-adhesive properties can be obtained by spinning a high-molecular-weight polyurethane or a high-hardness polyurethane, but the viscosity of the urethane polymer itself during melt spinning is low or low. When the prepolymer for viscosity crosslinking is mixed during spinning, the viscosity of the urethane polymer at the time of melting decreases, and when the yarn immediately after spinning is still soft and wound up, sticking due to adhesion of polyurethane appears strongly, and isocyanate group Sufficient anti-sticking properties cannot be obtained with the quenching agent alone.

The present inventors have proposed a spinning oil agent using amino-modified silicon in combination as an anti-sticking agent having both the releasing effect immediately after spinning and the effect of deactivating the active isocyanate group (Japanese Patent Publication No. 63-008233). No.). This method is soft during melt spinning, and exhibits excellent anti-sticking properties due to the release effect of dimethyl silicon chains and the deactivation of isocyanate groups by active hydrogen of amino groups even when a large amount of isocyanate groups are present on the yarn surface. However, the amino-modified silicone which has sufficient anti-sticking properties has a very low inter-fiber frictional force between the obtained yarns. The return thread will fall and roll. Amino-modified silicon having a weak anti-sticking property is used to maintain the wound shape, and the wound shape is maintained by the high speed of the thread due to the sticking and the high frictional force between fibers, so that the amino-modified silicon to be used must be limited.

As described above, various substances have been proposed as anti-sticking agents. However, in addition to anti-sticking properties, satisfactorily practical use including spinning and operability in post-processing steps has been found. Absent.

(Problems to be Solved by the Invention) In the method of the present invention, in the case of producing a polyurethane elastic yarn by mixing a prepolymer having isocyanate groups at both ends at the time of spinning, particularly at the time of spinning, the spinning bobbin at the time of spinning is stuck. The purpose of the present invention is to prevent bobbin shedding and crumble in the ascending and spinning processes and the subsequent process, and to provide smooth operability from the spinning process to the subsequent process. In detail, when amino-modified silicone is used as an anti-sticking agent, amino-modified silicone has excellent anti-sticking property. The frictional force between the fibers is too low, and the problem of spinning, bobbin tearing and collapse in the next process is improved. It is another object of the present invention to find an amino-modified silicone combination oil agent that can achieve both excellent anti-sticking property and good bobbin winding shape.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, when producing a polyurethane elastic yarn by kneading a polyisocyanate prepolymer as a crosslinking agent during melt spinning, mineral oil and / or General formula for linear polyorganosiloxane (R is an alkyl or alkoxy group having 1 or more carbon atoms,
R ₁ , R ₂ and R ₃ are an alkyl group having 1 or more carbon atoms, m and n are integers of 1 or more).
The present invention has been attained by adding a blended oil obtained by blending a polyorganosiloxane having a cyclic structure with 5 to 10% by weight to a polyurethane elastic yarn to 10% by weight.
In the present invention, the contradictory properties of anti-sticking property and bobbin wound shape retention, which could not be achieved by using amino-modified silicon alone, have been made possible by mixing and using a polyorganosiloxane having a cyclic structure.

The amino-modified silicone used in the present invention has both excellent properties of deactivating the isocyanate group on the yarn surface due to the active hydrogen of the amino group present in the molecule and the releasing action of the dimethylsilicone chain, and has extremely excellent anti-sticking properties. Shows sex. However, while this amino-modified silicone exhibits excellent anti-sticking properties, if there is a large amount of amino groups enough to deactivate all active isocyanate groups on the fibers, the resulting fiber will have extremely low fiber-to-fiber friction and spinning. The bobbin collapsed and could not be put to practical use, and if the amount of amino groups was reduced to such an extent that the collapse did not occur, sufficient sticking could not be obtained, so that it was not put to practical use. Therefore, a large amount of amino-modified silicon was blended, and as a result of examining a method that does not reduce the inter-fiber frictional force of the obtained yarn even if there is an amino group enough to obtain excellent anti-sticking properties, it has a ring structure It has been found that by adding an appropriate amount of polydimethylsiloxane, it is possible to maintain a high level of inter-fiber frictional force, which was impossible with the use of amino-modified silicon alone. Even when polydimethylsiloxane having a cyclic structure is used alone, it exhibits excellent anti-sticking properties immediately after spinning, but has no practical problem since it does not have a reactive group that deactivates the active isocyanate group. Was. Thus, the present invention can be used without any practical problems by appropriately mixing both amino-modified silicon and polydimethylsiloxane having a cyclic structure which could not be used due to various problems. It is like that.

The mineral oil used in the present invention may have any composition, but has a viscosity of 30 ° C. for uniform adhesion to the yarn and for preventing the yarn from being wound around the roller due to the viscous resistance of the oil during spinning.
Is preferably 5 to 50 cst.

As the linear polyorganosiloxane used in the present invention, dimethylpolysiloxane, methylphenylpolysiloxane and the like can be used. If it is necessary to improve the anti-sticking property by using this component, a long-chain alkyl-modified silicon or other low-viscosity modified silicon having a strong releasing effect may be used. In any case, low viscosity is better in terms of uniform adhesion, roller wrapping, and reduction of anti-stick spots.
Those having 5 to 50 cst at 30 ° C. are preferred. When the viscosity of both the mineral oil and the linear polyorganosiloxane is 5 cst or less, the volatility is high, and after volatilization, it volatilizes and disappears from the yarn surface, resulting in a decrease in the smoothness of the yarn and a decrease in the anti-sticking property.

The mineral oil and the linear polyorganosiloxane can be appropriately mixed and used according to the solubility of the amino-modified silicon and the polyorganosiloxane having a cyclic structure to be mixed. If the mixture cannot be dissolved only with the mineral oil and the linear polyorganosiloxane, less than 10% by weight of a fatty acid ester or a higher alcohol may be added. From the viewpoint of the anti-sticking property, the more the mineral oil, fatty acid ester and higher alcohol are contained in the linear polyorganosiloxane, the lower the anti-sticking property. Therefore, it is preferable to use the linear polyorganosiloxane alone as much as possible. .

The amino-modified silicon referred to in the present invention refers to polydimethylsiloxane in which an amino group is added to a molecular chain,
The methyl group of polydimethylsiloxane is other alkyl group,
Of course, substitution with an allyl group is also effective. There are a terminal type added to the molecular chain terminal of polydimethylsiloxane and a side chain type added in the middle of the molecular chain depending on the position of addition of the amino group, and a monoamine and diamine type depending on the structure of the amino group. From the viewpoint of the anti-sticking property, the effect of the addition position of the amino group is small, and the same effect can be obtained in the terminal type and the side chain type. On the other hand, the structure of the amino group is excellent because both the monoamine and diamine types exhibit excellent anti-sticking properties, but the diamine type is better than the monoamine type. The larger the amount of amino groups in the amino-modified silicon, the better the anti-sticking property. In addition, a higher viscosity gives a better anti-sticking property than a low viscosity. In the present invention, the amount of amino group is quantitatively expressed in terms of amino equivalent, and the smaller the amino equivalent, the larger the amount of amino group. Amino equivalent corresponds to the molecular weight of dimethylpolysiloxane per amino group and is defined and measured as follows.

Definition of amino equivalent: Method for measuring amino equivalent: Take about 1 g of a sample in a flask and stir. Add 25 ml of isopropyl alcohol, stir and dissolve well, and neutralize appropriately with 0.1 N hydrochloric acid using the indicator bromophenol blue.
Amino equivalent is calculated by the following formula.

In order to obtain excellent anti-sticking properties, amino-modified silicon having an amino equivalent of 15,000 or less is suitable. Amino equivalent 1500
If it is 0 or more, the anti-sticking property is inferior and the unwinding property in the subsequent process of the spinning bobbin is poor, which is not preferable. The combined amount of the amino-modified silicone must be changed according to the amount of isocyanate groups on the surface of the yarn, and it is necessary to use an amount that does not cause an increase in sticking over time. It is preferably 15% by weight, more preferably 0.5 to 10% by weight. If it is less than 0.1%, excellent anti-sticking property cannot be obtained, while if it is more than 15% by weight, the effect of blending the polysiloxane having a cyclic structure does not appear, and the frictional force between fibers decreases, and the spinning bobbin collapses, which is not preferable. .

The polyorganosiloxane having a cyclic structure used in the present invention can be prepared by a known method described in the prior art section (Japanese Patent Publication No. Sho 39
No. -24858), and is obtained by hydrolyzing an alkyl dihalogenated siloxane or an alkyl trihalogenated siloxane and further condensing the same.

It is not clear why the amino-modified silicon does not show the transient slipperiness when blended with amino-modified silicon, but due to the annular bulky structure, it reacts with the NCO groups on the yarn surface to form a smooth layer This is probably because a polyorganosiloxane layer having a cyclic structure with poor smoothness was formed outside the amino-modified silicon film. Polyorganosiloxanes having a cyclic structure have higher viscosity and are more excellent in anti-sticking properties and excessive anti-slip properties when blended with amino-modified silicone. High viscosity when blended with polyorganosiloxane
At the time of application to the yarn, an obstacle such as roller winding due to adhesion occurs. Therefore, usually those having a viscosity of 10000 ~ 20000 cst at 30 ° C., more preferably 1200
Those having 0 to 15000 cst are preferred.

The compounding amount of the polyorganosiloxane having a cyclic structure is appropriately determined depending on the amino equivalent of the amino-modified silicon used in combination and the amount used together. As the amount of amino group in the amino-modified silicon increases or as the amount of the amino group increases, the amount of the compound increases, but in the polyurethane elastic yarn of the present invention, the amount is 3 to 15% by weight, preferably 5 to 10% by weight. When the content is less than 3% by weight, the effect of preventing the slip property of the amino-modified silicon is insufficient,
If the content is more than 15% by weight, the viscosity of the compounded oil becomes high, and when applied to the yarn, troubles such as roller winding occur, which is not preferable. Therefore
It is necessary to select and use the amino equivalent of the amino-modified silicone and the amount of the amino-modified silicone used together so that a suitable anti-sticking property and a suitable slip property can be obtained with a blending amount of 10% by weight or less.

As a method for adhering the oil agent of the present invention to the polyurethane elastic fiber, a normal method such as a method of contacting with an oiling roller until the filament discharged from the spinneret is wound up or a method of lubricating with a metering discharge nozzle should be used. Can be. By attaching the oil agent of the present invention to the filament in an amount of usually 2 to 10% by weight, preferably 5 to 8% by weight, it has a suitable inter-fiber sliding property even immediately after spinning, and the spun bobbin does not collapse. In addition, due to the excellent anti-sticking property, there is no rise in sticking with time after spinning, and operations such as rewinding, covering, warping, knitting and the like in the subsequent process can be carried out smoothly.

Hereinafter, the present invention will be described in detail with reference to examples. In addition, as a method of evaluating the effect of the present invention, the unwinding tension which is a substitute property of the anti-sticking property, the inter-fiber friction force which is a substitute property of the inter-fiber slip property, and the state of spinning collapse were used. Each measuring method is as follows.

Unwinding tension: The tension required to tear off the yarn from the bobbin surface when the yarn is pulled out from the spinning bobbin at a take-up speed of 1 m / min (see Fig. 1). In this method, the maximum tension per 5 m of yarn length
The unwinding tension is the average of 20 points. The smaller the value is, the less the sticking is, and the more excellent the anti-sticking property is.

Inter-fiber friction force: Twist single yarns so that the total denier is 400d
A 10-filament yarn is formed at 0 d), and the secondary tension (T ₂ ) is measured by the crossover method shown in FIG.

1) Initial tension (T ₁ ) 1g 2) Number of yarn crossings: One twist (360 ° rotation) 3) Yarn speed 2cm / min Spinning collapse: 80mm width with a contact pressure between the spinning friction roller and bobbin of 500g ( 200φ winding bobbin) Observe the naked eye when winding a 40d yarn with a twill angle of 5mm at 500m / min for 10 hours. .

Example 1 Poly (1,4-oxybutylene) glycol 7 having a molecular weight of 2000
A polyurethane polymer polymerized from 0.6 parts, 4.9 parts of 1,4 butanediol and 24.5 parts of 4,4'-diphenylmethane diisocyanate is melted at 195 ° C., and before entering a screw type extruder, a poly (1,4 After mixing 20 parts of the (oxybutylene) diisocyanate with the polyurethane polymer,
It was extruded from a 5 mm nozzle and wound up on a bobbin at a spinning speed of 470 m / min to obtain a monofilament of 40 denier. Immediately before the monofilament was wound up, each of the seven types of oil agents shown in Table 1 was applied to the filament weight by 7% using an oiling nozzle.

 Table 1 shows the spinning results of each oil agent.

The oil agent C shown in the comparative example is an oil agent which does not contain any anti-sticking agent component and has a high inter-fiber friction force and a large inter-thread sticking, so that the spinning does not collapse. Was not able to be unwound and no rewinding was possible. Oil agents D and E are oil agents using only a polyorganosiloxane having a cyclic structure as an anti-stick agent. The inter-fiber frictional force is high and the spinning bobbin does not collapse, and the anti-sticking property immediately after spinning is good.
Since there was no component to deactivate the machine, agglutination after three months had passed was large and it was impossible to rewind. Oil agents F and G are oil agents using only amino-modified silicone as an anti-stick agent. Although having an amino group that inactivates the active NCO group, the anti-sticking property was extremely good, but the frictional force between the fibers was too low, so that the spinning bobbin collapsed and a predetermined amount of winding could not be obtained. On the other hand, the oil agents A and B of the present invention using a polyorganosiloxane having a cyclic structure and an amino-modified silicone in combination have excellent anti-sticking properties and a moderate inter-fiber friction force, and a predetermined amount of winding is performed in the spinning process. It was possible, and the rewinding property in the subsequent step was also good.

Example 2 Next, the effect of the polyorganosiloxane having a cyclic structure will be described. For the same spinning conditions as in Example 1,
An oil agent using linear polydimethylsiloxane having the same molecular weight as the polyorganosiloxane having a cyclic structure was applied to the yarn.

The oil agent I of the comparative example did not have the effect of keeping the inter-fiber friction force high, and the inter-fiber friction force was reduced, causing the spinning bobbin to collapse.

Example 3 The effect of the combined amount of a polyorganosiloxane having a cyclic structure and amino-modified silicon will be described.

Under the same spinning conditions as in Example 1, oils J to U shown in Table 3 were applied to the yarn. The same oil component as that of the oil agent A of Example 1 was used, and the combined amount of the polyorganosiloxane having a cyclic structure and the amino-modified silicon was changed.

The oils J, M, P, and S have poor anti-sticking properties over time because the combined amount of amino-modified silicon is small. In oils K and N, the combined amount of polyorganosiloxane having a cyclic structure is small, so if amino-modified silicon is used that can provide excellent anti-sticking properties, it will not be possible to maintain a high inter-fiber frictional force and problems with collapse will occur. I do. Oils L, O, R, and U provide excellent anti-sticking properties due to the excessive amount of amino-modified silicon used in combination, but the ability of polyorganosiloxanes with cyclic structures to maintain high inter-fiber frictional forces is far greater Since the amount of amino-modified silicon exceeds the above, the frictional force between the fibers becomes low, and crimping occurs during spinning. On the other hand, in the oil agents Q and T of the present invention, the combined amount of the polyorganosiloxane having a cyclic structure and the amino-modified silicone is appropriate, and the polyorganosiloxane having a cyclic structure has the effect of maintaining a high frictional force between fibers and the amino modification. Both the anti-sticking effect of silicon was successfully utilized, and the operability was good without any problem in spinning and rewinding in the subsequent process.

(Effects of the Invention) As described above, according to the method for producing a polyurethane elastic fiber of the present invention, there is no collapse of the spinning bobbin in the spinning step, and there is no increase in agglutination after a lapse of time. A bobbin free from yarn breakage due to poor unwinding can be obtained, and excellent operability can be obtained from the spinning process to the subsequent process.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method of measuring the unwinding tension, and FIG. 2 is a method of measuring the inter-fiber friction force.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D06M 15/687 D01F 6 / 70,6 / 94 D01F 11/08

Claims (4)

(57) [Claims] In producing a polyurethane elastic yarn by kneading a polyisocyanate prepolymer as a crosslinking agent at the time of melt spinning, a mineral oil and / or a linear polyorganosiloxane is represented by a general formula: (R is an alkyl or alkoxy group having 1 or more carbon atoms,
R ₁ , R ₂ and R ₃ are an alkyl group having 1 or more carbon atoms, m and n are integers of 1 or more).
A method for producing a polyurethane elastic yarn, comprising: applying a compounded oil obtained by mixing 5 to 10% by weight of a polyorganosiloxane having a cyclic structure with 5 to 10% by weight to a polyurethane elastic yarn, followed by winding. 2. The method according to claim 1, wherein the amino-modified silicon represented by the general formulas (I) and (II) has an amino equivalent of 15,000 or less. 3. The method according to claim 1, wherein the polyorganosiloxane having a cyclic structure is obtained by hydrolyzing and condensing an alkyldihalogenated siloxane or an alkyltrihalogenated siloxane. 4. The method according to claim 1, wherein the amount of the compound oil applied to the polyurethane elastic yarn is 5 to 10% by weight based on the amount of the yarn.