JP2015089980A - Polyethylene fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene fiber that can suitably be utilized in an area of clothing having an excellent handleability and processability while having an excellent cold-feeling.SOLUTION: Provided is a polyethylene fiber which is a fiber having a polyethylene as the major constituent, and is characterized in that the polyethylene has an intrinsic viscosity of 0.8 to 1.7, a strength at break of 2 to 8 cN/dtex, and a boiling water shrinkage percentage of in a range of 2 to 5%. Furthermore it is preferred that the fiber cross section shape is flat. And the method for producing said polyethylene fiber is characterized in melt-spinning and drawing a resin having a polyethylene of intrinsic viscosity of 0.8 to 1.7 as the major constituent, and bringing it into contact with a heat medium to perform heat set.

Description

  The present invention relates to a polyethylene fiber, and more particularly to a polyethylene fiber that can be suitably used for apparel with excellent handling properties while being excellent in cool feeling.

  Along with the recent increase in comfort orientation, textile products have been developed that, when worn as clothes, can feel a moderate cool feeling, especially when the ambient environmental temperature is relatively high, such as in summer. Among them, those represented by fibers such as high-strength polyethylene having high crystallinity and high orientation described in Patent Document 1 are known to have high thermal conductivity and high comfort.

  However, fabrics made of such highly crystalline and highly oriented high-strength polyethylene fibers can surely get a cool feeling of contact, but the productivity of fibers compared with general-purpose synthetic fibers made of ordinary thermoplastic resin. There was a problem of being inferior. The melt temperature at the time of spinning is high, a large amount of heat is required, the spinning speed is low, and highly efficient production is difficult. Furthermore, when the produced fiber is used as a fiber for clothing, there is a problem that the handleability at the time of processing is inferior.

  On the other hand, as fibers that place importance on cooling feeling, Patent Document 2 proposes using a hygroscopic polymer as a polymer constituting the fiber, and Patent Document 3 proposes using a thermoplastic elastomer. Yes. However, the hygroscopic polymer causes stickiness during sweating, causing discomfort, and the elastomer has its own stickiness and is inferior in processing characteristics.

Patent Documents 4 and 5 disclose a technique in which a fabric having a cool feeling is attached by post-processing after forming a fabric made of normal synthetic fiber or natural fiber. However, in addition to the low thermal conductivity of the fiber itself, the adhesion of the agent by post-processing has problems such as deterioration of the texture due to the binder serving as an adhesive and washing durability, and is also inferior in handleability. there were.
As described above, fibers that are easy to handle while having a sufficient cooling sensation sufficient for practical use have not been obtained, and improvements are desired.

JP 2010-236130 A JP 2003-293223 A JP 2004-270075 A JP 2007-224429 A JP 2006-161226 A

  The object of the present invention was made against the background of the above-described conventional technology, and the object thereof is to provide a polyethylene fiber that can be suitably used for apparel applications that are excellent in handling and workability while being excellent in cooling feeling. is there.

The polyethylene fiber of the present invention is a fiber mainly composed of polyethylene, and has an intrinsic viscosity of 0.8 to 1.7, a breaking strength of 2 to 8 cN / dtex, and a boiling water shrinkage of 2 to 5%. It is characterized by being in the range of Furthermore, the fiber cross-sectional shape is preferably flat.
Another method for producing a polyethylene fiber according to the present invention is to melt-spin, stretch, and heat-set a resin mainly composed of polyethylene having an intrinsic viscosity of 0.8 to 1.7 and contact a heat medium. Is a manufacturing method characterized by

  ADVANTAGE OF THE INVENTION According to this invention, the polyethylene fiber which can be utilized suitably for the garment use excellent in the handleability and workability, while being excellent in cool feeling is provided.

It is a schematic diagram which shows an example of the cross section orthogonal to the fiber axis of the fiber of this invention. It is a schematic diagram which shows the other example of the cross section orthogonal to the fiber axis of the fiber of this invention.

The polyethylene fiber of the present invention is a fiber mainly composed of polyethylene, and has an intrinsic viscosity of 0.8 to 1.7, a breaking strength of 2 to 8 cN / dtex, and a boiling water shrinkage of 2 to 5%. It is a fiber that is essential to be in the range.
Here, polyethylene which is a main constituent component can be classified into high density polyethylene, linear low density polyethylene, low density polyethylene and the like. Among them, the polyethylene used in the present invention is preferably high-density polyethylene, and it is possible to obtain high heat conductivity with high performance as well as higher yarn-making properties.

  The main component polyethylene is preferably composed of a single component, but if it is less than 5% by weight, it is also preferred that a C3-C12 higher alkene is contained as a copolymer. Furthermore, in the polymer constituting the fiber of the present invention, conventionally known antioxidants, light proofing agents, flame retardants, pigments and the like can be contained within a range not impairing the object of the present invention.

  And the polyethylene fiber of this invention which has such a polyethylene as a main component needs that the intrinsic viscosity is 0.8-1.7 (dl / g). When the intrinsic viscosity is lowered, particularly less than 0.8, it is difficult to obtain physical properties such as desired strength when a fiber is obtained. On the other hand, the intrinsic viscosity becomes high, especially when it exceeds 1.7, the fluidity is lowered, and although melt spinning is barely possible, the melting temperature has to be raised and the production efficiency is reduced. It will be accompanied by thermal decomposition. This intrinsic viscosity was measured later as a fiber, more preferably in the range of 0.9 to 1.5 (dl / g), particularly in the range of 1.0 to 1.2 (dl / g). It is preferable that

  The polyethylene fiber of the present invention needs to have a breaking strength (St) of 2 to 8 cN / dtex. If the breaking strength is less than 2 cN / dtex, there may be a problem in processing and use in terms of strength. On the other hand, if it exceeds 8 cN / dtex, the handleability and productivity in processing such as cutting are reduced. The preferred range is 2.5 to 6 cN / dtex, and the fiber is particularly excellent in processability.

  Further, the elongation at break is preferably in the range of 10 to 50%. Further, the elongation is preferably 15 to 30%. Here, if the elongation of the fiber is too low, the handleability is poor, and conversely, if the elongation is too high, the fiber structure becomes unstable, and the physical properties may change over time. Considering the productivity of the fiber and the subsequent workability, it is particularly preferable that the breaking strength (St) is 2.5 to 6 cN / dtex, and the elongation at break is 15 to 30%.

  Further, the polyethylene fiber of the present invention needs to have a boiling water shrinkage of 2 to 5%. If the boiling water shrinkage is too low, particularly less than 2%, the surface quality of the fabric may be lowered. On the other hand, when the shrinkage increases as it exceeds 5%, the surface quality is deteriorated particularly during knitting and weaving with other fibers, making it difficult to obtain a soft texture.

The fiber of the present invention preferably has a flat cross-sectional shape. By adopting the flat shape, when the cloth for clothing is used, the contact area with the skin can be effectively increased, and the feeling of cool contact can be more fully felt.
The ratio A / B ₁ between the flat-shaped major axis width A and the minor axis maximum width B ₁ perpendicular thereto is preferably in the range of 2-10. If the ratio A / B ₁ between the major axis width A and the minor axis maximum width B1 perpendicular to it is too small, it becomes close to a round cross section and the effect of the flat shape is reduced, while if too large, the flat effect is improved. In addition, there is a tendency to increase the concern that process stability at the time of yarn production is lowered. A particularly preferable A / B ₁ ratio range is 3 to 8.

  Furthermore, the cross-sectional shape of the fiber of the present invention is preferably an irregular cross-section. In particular, it is a shape in which round cross-section single yarns are linearly connected in the major axis direction of the cross section, and preferably has a shape having 2 to 5 constricted portions. By adopting a flat cross-sectional shape as a whole in which single yarns with round cross-sections are linearly connected, there is less space between single yarns compared to the case where a single round cross-section single yarn exists alone. Thus, it is possible to effectively express the cooling effect. In addition, the bending properties of the fibers are improved, and the fabric is rich in flexibility.

  Furthermore, as a cross-sectional shape of the fiber of the present invention, it has a constricted portion in addition to a flat shape, so that irregular reflection on the fiber surface and light refraction effect can be further enhanced, and a certain degree of permeation can be imparted. It becomes. Usually, such an effect is obtained by reflection of inorganic compound particles, but the content can be effectively reduced. However, if the number of constricted portions is too small, the above-mentioned effect is hardly obtained. Conversely, if the number of constricted portions is too large, the process stability tends to be lowered. Therefore, a constricted portion of 3 to 4 is particularly preferable. .

In the case where such round cross-section single yarns are linearly connected, the ratio A / B ₁ between the long axis width A of the flat cross section and the maximum width B1 of the short axis perpendicular thereto is in the range of 2-6. Preferably there is. When the flatness is too small, it is difficult to obtain the effect of the flat cross section, and in the case of a fabric such as a woven or knitted fabric, the long axis is difficult to be arranged parallel to the fabric surface, and the heat shielding property may be lowered. On the other hand, if the flatness is too large, the spinning stability tends to decrease, and therefore a more preferable range is 3 to 5.

Further, in the case where the circular cross-section single yarns are linearly connected in this way, the ratio B ₁ / B between the maximum width B ₁ of the short axis of the flat cross section and the minimum width B ₂ of the short axis corresponding to the constricted portion. B ₂ is preferably 1.05 or more and 2 or less. If B ₁ / B ₂ is small, the effect of connecting the above-described round cross sections may be reduced, and if B ₁ / B ₂ is too large, the thickness of the connecting part (constriction part) becomes thin, and a cooling sensation effect is obtained. Tend to decrease. A particularly preferable range of B ₁ / B _{2 is} a range of 1.1 to 1.6.

  The single yarn fineness of the fiber of the present invention is preferably in the range of 1 to 10 dtex. If the single yarn fineness is too small, the spinning stability is lowered, and the fine voids between the fibers are increased, the heat insulation between the fibers is increased, and the cooling effect may be reduced. On the other hand, if the single yarn fineness is too large, the inter-fiber distance becomes large when the woven or knitted fabric is used, the contact area decreases, the cooling effect on the contact decreases, and the texture may become hard. As the single yarn fineness, a range of 0.5 to 8 dtex is more preferably used.

  As another method for producing the polyethylene fiber of the present invention, a resin mainly composed of polyethylene having an intrinsic viscosity of 0.8 to 1.7 is melt-spun, stretched, brought into contact with a heat medium and heat-set. It is a manufacturing method. Furthermore, it is preferable that the spinning speed is 500 to 3000 m / min and the draw ratio is 2 to 8. Here, as the main component polyethylene used in the fiber manufacturing method of the present invention, the polyethylene used in the above-described polyethylene fiber of the present invention can be used, and the method of spinning the fiber of the present invention includes: It is necessary that the melt spinning method is excellent in cost.

  Furthermore, as a method of stretching the fiber obtained by spinning the fiber, known hot roll stretching or hot water stretching can be used. This drawing step may be performed after the spun yarn is once taken up, or may be continued without being wound up. At that time, in order to define the boiling water shrinkage ratio of the fiber of the present invention, it is preferable that the fiber is stretched at a magnification of 70 to 95% of the stretch ratio at which the fiber breaks (breaking stretch ratio), and heat set after the stretching. . If the draw ratio is too low, the shrinkage rate tends to be excessive regardless of the heat setting temperature even if heat setting is performed thereafter. When the draw ratio is too large, fiber breakage or the like occurs and the process stability tends to become unstable. The range of the preferable draw ratio of the present invention is 80 to 90% of the break draw ratio. The preheating temperature during stretching is preferably in the range of 80 to 100 ° C. Stretching is preferably performed in two or more stages, and it is also preferable to perform relaxation treatment after stretching. The draw ratio is preferably 2 to 8 times. Furthermore, the draw ratio is preferably 4 to 6 times, and depending on the spinning ratio, it is possible to effectively set the shrinkage ratio of the fibers by employing a draw ratio in such a range.

  Furthermore, in the method for producing a polyethylene fiber of the present invention, it is necessary to further heat set after stretching. And as a method of heat setting, it is necessary to be a method of directly contacting the heating medium, and roller heat setting with a long contact time is particularly preferable. In the case of using a non-contact type slit heater, heat setting becomes insufficient, which causes spots. The heat setting temperature is preferably as high as possible within the range in which breakage due to fusion or melting does not occur. The heat setting temperature is preferably in the range of 100 to 130 ° C. and is preferably treated for 0.1 to 0.5 seconds. Further, the heat set temperature is preferably in the range of 105 to 125 ° C. If the heat set temperature is too low, the physical properties tend to fluctuate easily. Conversely, if the temperature is too high, the fibers tend to be fused to the roller of the heating element. The heat setting time is preferably in the range of 0.15 to 0.4 seconds. If the time is too short, the shrinkage rate tends to be low, and the polyethylene fiber of the present invention tends to be difficult to obtain. If the time is long, scum is generated and the process passability tends to deteriorate.

Moreover, in the manufacturing method of the polyethylene fiber of this invention, it is preferable to wind up, after adjusting winding-up tension | tensile_strength or carrying out overfeed (relaxation) between the heat | fever setting roller and cooling roller after extending | stretching.
In the process of spinning and stretching the fiber, it is preferable to use a known antistatic agent, fiber finishing agent or the like as necessary.

  When the polyethylene fiber of the present invention is used as a fabric, it is also preferable to partially use the fiber of the present invention in addition to using the fiber of the present invention for all the fabrics. The structure of the fabric is not particularly limited, and the fabric can be used in the form of a woven fabric, a knitted fabric, or a non-woven fabric. The fabric has high productivity and workability while being excellent in cooling feeling.

  Next, the present invention will be described more specifically with reference to examples. The evaluation and measurement in the examples were performed as follows.

(1) Intrinsic viscosity Using an Ubbelohde capillary viscosity tube, the reduced viscosity of various solution concentrations was measured with decahydronaphthalene at a temperature of 135 ° C. with an automatic viscometer device (manufactured by Rihga Co., Ltd.). The relational expression was obtained from the graph plotting the relation of the reduced viscosity, and the reduced viscosity when the sample solution concentration was extrapolated to zero was obtained as the limiting viscosity. The measurement solution was adjusted by adding 1% by weight of “Yoshinox BHT” (manufactured by API Corporation) and dissolving by shaking at 145 ° C. for 1 hour.

(2) Tensile strength of fiber, shrinkage rate of boiling water Measurement was performed according to the method described in JIS L1013.

(3) Fiber cross-sectional shape From a cross-sectional photograph of a fiber with a magnification of 500 times by a transmission electron microscope, “long-axis width A” and “maximum short-axis width B ₁ perpendicular to the long axis” per 20 single yarns Then, the value of “minimum width B ₂ of the short axis corresponding to the constricted portion and orthogonal to the long axis” was measured, and the flatness ratios A / B ₁ and B ₁ / B ₂ were calculated from the average value.

(4) Fiber density (gas displacement method)
The density of the obtained fiber was measured by a gas substitution method using a dry automatic densimeter (manufactured by Micromeritics, “Acubic 1330-03”). The measurement temperature was 25 ° C., and the filling gas was helium.

(5) Evaluation of contact cooling sensation A tube knitting with a basis weight of 150 g / m ² was created using the obtained fiber, and the presence or absence of cooling sensation at the moment when 10 subjects touched the fabric was evaluated according to the following criteria. The average score of 10 people was obtained and evaluated.
3 points: I felt a cool feeling that I could clearly experience.
2 points: I felt a little cold.
1 point: A slight cold feeling was felt.
0 points: No cold feeling was felt.
Also, the fabric is 8 cm × 8 cm in size, placed on a 0.5 mm thick stainless steel plate 10 cm × 10 cm in size that has been pre-warmed to 40 ° C., and the temperature at the center of the stainless steel plate is measured with a thermocouple. The temperature drop was measured and evaluated by the temperature difference from the following reference example.

[Reference Examples 1 and 2]
The same fibers were obtained in the same manner as in Examples 1 and 2 below, except that polyethylene terephthalate (inherent viscosity; 0.63) was used instead of the polyethylene resin. A cylindrical knitting was made in the same manner as in Examples 1 and 2 below, and used as a criterion for evaluation of cooling feeling.
The temperature difference in the evaluation of cooling sensation is the difference between the maximum drop temperature of Reference Example 1 for Example 1 and Comparative Example 1, and the maximum drop of Reference Example 2 for Example 2 and Comparative Examples 2-4. The temperature difference with temperature was shown.

(6) Stability of yarn making In the spinning and drawing processes, the number of times of yarn breakage per day, the number of windings of a single yarn is 0 to 1 times, 2 to 4 times ○, 5 to 8 times Δ, 9 times or more × evaluated.

[Example 1]
High-density polyethylene (melt flow rate according to JIS K-7210; 19) is melted by an extruder set at 220 ° C., and discharged at a temperature of 215 ° C. from a die having 36 holes with a round cross section. It wound up at 1500 m / min. The wound undrawn yarn was drawn under the conditions of a preheating temperature of 100 ° C., a heat setting temperature of 120 ° C. and a draw ratio of 4.4 times, and contacted with a heating roller to perform heat setting at 120 ° C. for 0.18 seconds, and 60 dtex / 36files. A polyethylene fiber having a single yarn fineness of 1.7 dtex and a fiber density of 0.97 was obtained.
Further, two obtained fibers were combined to create a tubular knitting, and the cool feeling was evaluated. Table 1 shows the physical properties and evaluation results of the obtained fibers.

[Comparative Examples 1 and 2]
By changing the polyethylene of Example 1, Comparative Example 1 which was a polyethylene fiber having an intrinsic viscosity of 0.52 dl / g and Comparative Example 2 which was a polyethylene fiber having an intrinsic viscosity of 1.8 were produced. In the production of the fiber of Comparative Example 2, the melting temperature was changed to 280 ° C. and the discharge temperature from the die was changed to 270 ° C. In Comparative Example 1, 60 dtex / 36 files. Polyethylene fiber having a fiber density of 0.94 was compared with 60 dtex / 36 fils. A polyethylene fiber having a fiber density of 0.98 was obtained. Table 1 also shows the physical properties of the obtained fiber and the evaluation results of the tubular knitting made using this fiber.

[Comparative Examples 3 and 4]
The heat set after stretching in Example 1 was replaced with a non-contact type slit heater set (processing time 0.046 seconds) instead of the contact type heating set roller, and the heat setting conditions were 180 ° C. in Comparative Example 3, In the comparative example 4, it changed into 200 degreeC and implemented. In Comparative Example 3, 60 dtex / 36 files. Although a polyethylene fiber was obtained, in Comparative Example 4, yarn breakage occurred and a satisfactory fiber could not be obtained. Table 1 also shows the physical properties of the obtained fiber and the evaluation results of the tubular knitting made using this fiber.

[Example 2]
60 dtex / 36 films.similarly to Example 1 except that a base having 36 hole discharge holes having the cross-sectional shape shown in FIG. A polyethylene flat cross-section fiber having a fiber density of 0.97 was obtained. The cross-sectional shape of the obtained fiber was a constriction number 3, flatness 4, and B ₁ / B ₂ = 1.5. Table 1 also shows the physical properties of the obtained fiber and the evaluation results of the tubular knitting made using this fiber.

As shown in Table 1, Examples 1 and 2, which are within the scope of the present invention, were excellent in yarn-making property and physical properties and excellent in cooling feeling when used as a fabric. Furthermore, 84 de / 36 fils. When a shirt was made by knitting with a polyester fiber and a circular knitting and evaluated for wearing, it was excellent both in coolness and quality.
Comparative Example 1, which has a low intrinsic viscosity and only 0.52 dl / g, is inferior in strength. Conversely, Comparative Example 2, which has an intrinsic viscosity as large as 1.8 dl / g, has difficulty in spinning and is inferior in process stability. there were.

  On the other hand, in Comparative Example 3 using a non-contact type slit heater at the time of heat setting after stretching, the shrinkage rate is high, and the shirt produced by knitting as in Example 2 has a certain cool feeling, but the fabric Unevenness was generated on the surface during setting, and the quality was inferior. Similarly, in Comparative Example 4 where the temperature of the non-contact type slit heater was raised to 200 ° C., yarn breakage occurred and fibers could not be obtained.

  The polyethylene fiber of the present invention is excellent in cooling sensation, has high productivity, is easy to handle, has a refreshing feeling when used as a fabric, and is used in many applications such as clothing such as sports and outerwear, and industrial materials. The industrial value is extremely large.

A: Width of major axis in cross section of flat fiber B ₁ : Maximum width of minor axis perpendicular to major axis of flat fiber section B ₂ : Short width perpendicular to major axis of flat fiber section corresponding to constricted portion Axis minimum width

Claims (3)

  A fiber mainly composed of polyethylene, wherein the polyethylene has an intrinsic viscosity of 0.8 to 1.7, a breaking strength of 2 to 8 cN / dtex, and a boiling water shrinkage of 2 to 5%. Polyethylene fiber.   The polyethylene fiber according to claim 1, wherein the fiber cross-sectional shape is flat.   2. The production of polyethylene fiber according to claim 1, wherein a resin mainly composed of polyethylene having an intrinsic viscosity of 0.8 to 1.7 is melt-spun, stretched, brought into contact with a heat medium and heat-set. Method.

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