JPS638233B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing polyurethane elastic fibers by a melt spinning method. More specifically, the present invention relates to a method for preventing bobbin threads from sticking by applying an oil to the fibers during melt spinning of polyurethane elastic fibers. (Prior art) Melt spinning, dry spinning, wet spinning, etc. have been commonly used to obtain polyurethane elastic fibers, but in any of these methods, the fibers are wound around a bobbin during spinning. At this time, the fibers stick to each other, and therefore, when the bobbin is unwound, a large tension or uneven tension occurs, which is the main cause of thread breakage in the subsequent process. Many proposals have been made for methods of preventing this stalemate. For example, a method has long been proposed in which an aqueous or oil-based slurry of mineral solid fine particles such as talc, silica, and colloidal alumina is applied to fibers. Although these methods are certainly effective in preventing bobbin thread from sticking together, it is difficult to maintain uniform dispersion of solid particles in water or oil, making it difficult to prevent threads from sticking uniformly and making it difficult to unravel bobbin thread. Large tension unevenness during sowing;
Further, there are disadvantages such as solid fine particles falling into the yarn path in subsequent steps, large tension fluctuations, and abrasion of the contact portion of the yarn due to the solid fine particles. Avoiding mineral solid particles, metal salt powder of higher fatty acids is dispersed in water or oil based on mineral oil (Japanese Patent Publication No. 41-286, Japanese Patent Publication No. 40-1986)
5557), a method of dispersing and dissolving room-temperature solid waxes such as higher aliphatic carboxylic acids, higher aliphatic alcohols, paraffin, and polyethylene in an oil agent mainly composed of mineral oil (Japanese Patent Publication No. 1972-272, Japanese Patent Publication No. 1973-
9955, Japanese Patent Publication No. 44-8907) have also been proposed. However, these methods eliminate wear spots at the thread contact area due to the softness of the dispersed solids, but the dispersion and dissolution are still unstable, resulting in uneven adhesion to the threads and scum of the solids. It is difficult to completely avoid falling into the thread path. Polyalkylene oxide-modified silicone oil is the most well-known material that is liquid at room temperature and has good anti-stick properties.
Publication No. 40719, Japanese Patent Application Publication No. 1989-19893, Japanese Patent Application Publication No. 1989-1989
-128270). In particular, the higher the molecular weight of the added polyalkylene oxide, the greater the anti-sticking performance, but the viscosity increases, and the frictional resistance of the thread is so high that it cannot be used as it is, so base oils such as low-viscosity mineral oil and silicone oil are used. Needs to be dissolved. However, the solubility of high molecular weight polyalkylene oxide-modified silicone oils in these base oils is extremely low, and even if a compatibilizer such as a higher alcohol or its fatty acid ester is used, there is a limit to the amount of solubility, and as a result, the solubility is limited. In addition, these compatibilizers often deteriorated the quality of the polyurethane elastic yarn. Furthermore, it must be pointed out that the sticking of the bobbin yarn during spinning of polyurethane elastic yarn is not due to mere adhesion due to the rubber-like properties of polyurethane, but seems to be due to chemical bonding. That's true. That is, after spinning, the reactive isocyanate end groups of the urethane polymer exist on the surface of the filament wound onto a single-carrying bobbin for several days, and the allophanate bonds and other chemical bonds are formed at the interface where the filaments come into contact with each other. It is thought that it forms between filaments and makes their adhesion stronger. This phenomenon is particularly noticeable when polyurethane elastic fibers are produced by melt spinning. As a method for preventing sticking caused by chemical bonding of isocyanate terminal groups, a method has been proposed in which mineral oil in which monoamines have already been dissolved is applied during spinning, and the monoamines deactivate the isocyanate terminal groups. 46-16312), and oil agents containing appropriate diamines have also been proposed by the present inventors (Japanese Unexamined Patent Publication No. 132170/1982). However, the effect of these amines is limited to deactivating the reactive groups of the filament.
Polyurethane has no effect on sticking caused by the adhesion of the rubbery substance, and as mentioned above, polyalkylene oxide modified silicone also has a limited anti-sticking property, so the polymer viscosity is low especially during melt spinning, making it difficult to wind up on a bobbin. If the filament is still soft at the moment of weaving, or the denier of the fiber is
When the bobbin thread is as thin as 20 deniers or less, prevention of sticking of the bobbin thread is still insufficient in many cases. (Problems to be Solved by the Invention) The present invention solves problems such as sticking of bobbin thread, uneven sticking, scum falling into the thread path, and thread breakage accompanying this, when producing polyurethane elastic fibers by the melt spinning method. This is what we are trying to solve. (Means for Solving the Problems) In order to solve the above problems, the present invention involves blending amino-modified silicone with mineral oil and/or polydiorganosiloxane when producing polyurethane elastic fibers by a melt spinning method. , the viscosity is
It is characterized by applying a blended oil of 100 centistokes (30°C) or less to polyurethane elastic fibers and then rolling them up. The mineral oil referred to here has a viscosity of 100 centistokes (hereinafter referred to as CS) (30℃) as a whole blended oil.
Any material may be selected as long as it is within the following range, but a material with a low viscosity of about 4 to 25 CS is usually desirable from the viewpoint of ease of dissolution with other oil components and reduction of fiber friction. Polydiorganosiloxane is most desirable because polydimethylsiloxane is a commonly used product, but some of the methyl groups may be substituted with other monovalent organic groups such as alkyl groups and phenyl groups. As with mineral oil, the viscosity can be any value as long as the viscosity of the entire blended oil is 100CS (30℃) or less, but
Usually, a low viscosity type of about 5 to 20 CS is preferable for the same reason as mineral oil. However, since higher viscosity silicone oil generally has higher mold release properties, using a high viscosity type silicone oil in only a portion can also be expected to have some anti-sticking properties. The mixing ratio of mineral oil and polydiorganosiloxane (including each alone) depends on the amino group content, viscosity, blending ratio, etc. of the amino-modified silicone blended into the mixture of the two. That is, depending on these conditions, amino-modified silicones may be difficult to dissolve in mineral oil or polydiorganosiloxane, resulting in some separation and cloudiness. Compound oils with poor solubility for amino-modified silicones tend to cause problems such as uneven adhesion and scum falling off into the yarn path. The present invention requires that the amino-modified silicone be completely dissolved in the mineral oil, polydiorganosiloxane, or mixture thereof. In order to completely dissolve the amino-modified silicone, it is within the scope of the present invention to add a portion of a compatibilizer such as alcohol or ester to the blended oil, but these compatibilizers may cause deterioration of the thread quality of polyurethane fibers or Since this often leads to a decrease in anti-stick properties, it is desirable to keep the amount to less than 10% of the total blended oil. It is most desirable to completely dissolve the modified silicone. The amino-modified silicone used in the present invention generally refers to polydimethylsiloxane with an amino group added to its molecular chain, but it is of course also effective to substitute the methyl group with another alkyl group or allyl group.
Depending on the position of the amino group, there are side chain types and single terminal types, and the amino group itself can be monoamine, diamine, etc., but both are effective. viscosity,
As for the amino group content, it shows anti-sticking properties to a greater or lesser extent, and it is sufficient as long as the viscosity of the entire compounded oil is 100CS (30℃) or less.In general, the anti-sticking properties of bobbin thread are The higher the amino group content of the modified silicone, the better; if there is an extreme difference in viscosity, the higher the viscosity, the better. However, in melt spinning, the fibers immediately after spinning are extremely soft, and the viscosity of the blended oil applied at that time is 100CS.
If this is the case, the viscosity of the oil will cause high friction in the oiling roller, guide nozzle, or other thread contacting parts, making loose filaments and thread breakage likely to occur, which is undesirable. Most preferably, the viscosity of the blended oil is 20CS or less. Even a very small amount of amino group content in amino-modified silicone is effective in preventing adhesion, but in order to ensure this effect, the proportion (compounding ratio) of amino-modified silicone in the total blended oil must be at least 0.1% by weight. Amino equivalent of amino-modified silicone (Note 1)
It is desirable to keep it below 10000. On the other hand, the higher the blending ratio of amino-modified silicone and the lower the amino equivalent, the more difficult it becomes to dissolve the amino-modified silicone in mineral oil and polydiorganosiloxane, so the blending ratio of amino-modified silicone is 20% by weight. Below, an amino equivalent of 300 or more is desirable. Note that the oil agent used in the present invention is mineral oil,
It consists of polydiorganosiloxane and amino-modified silicone, but it also contains other anti-stick ingredients.
For example, conventional mineral solid particles such as talc, silica, and colloidal alumina, metal salt powders of higher fatty acids, room temperature solid waxes such as higher aliphatic carboxylic acids, higher aliphatic alcohols, paraffin, and polyethylene, or high molecular weight Polyalkylene oxide-modified silicone oil or amines may be additionally blended, and as long as they are not reactive with amino groups, the additional blending will increase the anti-sticking effect accordingly. However, because the effects of amino-modified silicone are so great, it is not really necessary to add such additional ingredients, and on the contrary, it can cause wear and tear in the thread guide area.
It is generally not recommended because problems such as scum falling off and uneven adhesion are expected. Further, although the present invention relates to a method for preventing melting of polyurethane elastic fibers, it does not necessarily deny the effectiveness of applying the oil agent of the present invention to other spinning methods. In the present invention, the amino group content is expressed quantitatively by amino equivalent, and the relationship is such that the smaller the amino equivalent, the larger the amino group content. Definition of amino equivalent: Amino equivalent =
Sample weight/number of moles of amino groups Measuring method of amino equivalent: Take about 1 g of sample in a flask and stir. Add 25 ml of isopropyl alcohol, stir well to dissolve, and neutralize appropriately with 0.1N hydrochloric acid using the indicator bromophenol blue. The amino equivalent is calculated using the formula below. Amino equivalent = 10 ⁴ × (sample weight g) / (potency of 0.1N hydrochloric acid) × (consumption amount of 0.1N hydrochloric acid ml) The blended oil in the present invention is mineral oil or polydiorganosiloxane or a mixture thereof as a base oil agent. Of course, mineral oil and polydiorganosiloxane themselves have some ability to prevent sticking of bobbin thread, but most of the anti-sticking performance lies in the amino-modified silicone; The polydiorganosiloxane merely enables the amino-modified silicone to fully exhibit its effects. It is not clear how amino-modified silicone exerts its anti-sticking properties, but according to the inventors' estimation, the amino groups of amino-modified silicone are still present on the surface of polyurethane fibers immediately after melt-spinning. It is thought that the silicone is strongly bonded to the isocyanate groups remaining in large numbers in the silicone, or even without bonding, it is strongly adsorbed to the fiber surface, and the silicone molecular chains connected to the amino groups strongly cover the fiber surface. Silicone originally has good mold releasability, but in the past, it was not sufficiently bonded or adsorbed to the fiber surface, so it could not perform its original function. It is presumed that, thanks to this, its original function was fully demonstrated. (Examples) Hereinafter, the present invention will be illustrated by examples. Example 1 Polytetramethylene glycol with a molecular weight of 1200
69.4 parts, 1,4 bis(β-hydroxyethoxy)
A polyurethane elastomer polymerized from 6.2 parts of benzene and 24.4 parts of 4,4-diphenylmethane diisocyanate was melted at 206°C, extruded through a nozzle using a screw extruder, wound around a bobbin at a spinning speed of 500 m/min, and made into a 20-denier material. A monofilament was obtained.
Immediately before winding, an oil having the following composition was applied to the filament in an amount of about 10% by weight using a guide nozzle.

【table】

[Table] The compounding ratio of each oil agent is a weight ratio. The viscosity of all the blended oils was 100CS or less. The spinning results for each oil agent are shown in Table 1.

[Table] Since oils A to H all use low-viscosity mineral oil or low-viscosity silicone oil as the base oil, the viscosity of the blended oils was 100CS or less, and there were no loose filaments or yarn breakage during spinning. Comparative Example G is an oil agent in which fine solid particles of magnesium stearate are dispersed, and although it has an excellent anti-sticking effect, the dispersion in the oil agent is unstable, so it falls off as scum on the thread path. Comparative Example F was an oil containing a polyalkylene oxaside-modified silicone and a diamine, and although there was no scum falling into the yarn path, the anti-sticking effect was slightly inferior. Oil agent H was an oil agent containing only mineral oil and polydimethylsiloxane and had an extremely weak anti-sticking effect. Oils A to E are oils according to the present invention, and although the mixing ratio of mineral oil and polydimethylsiloxane and the type and amount of amino-modified silicone are different, all of them are not only better than Oil H, which is made only of base oil, but also have the highest stickiness ever. It exhibited better anti-sticking performance than oils F and G, which were said to have good anti-sticking properties, and showed good operability with fewer thread breakages in subsequent processes. Example 2 The table below shows the results obtained by changing the viscosity of the blended oil under the same spinning conditions as in Example 1. The oil agent is a mixture of mineral oil and polydimethylsiloxane (95 parts) and an amino equivalent.
9000 and 5 parts of amino-modified silicone with a viscosity of 90CS.The viscosity was adjusted by changing the viscosity of the mixture of mineral oil and polydimethylsiloxane.

[Table] As shown in Table 2, the blended oil viscosity is 100CS.
In the following cases, the anti-sticking properties were good, and no thread breakage or loose filaments were observed during spinning.However, when the blended oil viscosity exceeds 100CS, the above-mentioned troubles occur frequently during spinning, and complete urethane elasticity is not observed. I couldn't get a bobbin for thread. (Effects of the Invention) As described above, according to the polyurethane elastic fiber production method of the present invention, bobbin thread sticking is extremely low, and thread breakage and loose filament during spinning are prevented.
There is no scum falling off, etc., and bobbin thread with less thread breakage can be obtained in the subsequent process.

Claims (1)

[Claims] 1 When producing polyurethane elastic fibers by the melt spinning method, a blended oil with a viscosity of 100 centistokes (30°C) or less, which is made by blending amino-modified silicone with mineral oil and/or polydiorganosiloxane, is applied to the polyurethane elastic fibers. A method for producing polyurethane elastic fiber, which is characterized in that it is rolled up after being rolled up.