JPH02234946A - Sheet - Google Patents

Abstract

PURPOSE:To obtain the subject sheet composed of a spun yarn containing a staple of a bicomponent conjugated fiber composed of a core component consisting of a polyester having a high softening point and a sheath component consisting of another polyester having a low softening point covering the periphery of the former polyester component in a specified ratio in a specified ratio and capable of stiff finish only by ironing. CONSTITUTION:A polyester having a high softening point such as >=240 deg.C and another polyester having a low softening point such as 70-180 deg.C are used respectively as the core and sheath components and spinning is carried out using a sheath-core bicomponent spinning machine to obtain a bicomponent conjugated fiber in which the sheath component with 0.5-5mum thickness covers >=60% of the periphery of the core component. A staple of the resultant bicomponent conjugated fiber is mix spun with another staple of cotton, etc., in a ratio of 3-20wt.%, preferably 5-15wt.% and the obtained spun yarn is woven, thus obtaining the objective sheet capable of a same finish only by ironing as that by ironing in combination with sizing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to sheets such as futons and beds. More specifically, the purpose is to provide sheets that can have a crisp finish similar to that obtained by applying starch during washing and ironing only by ironing.

[Conventional technology] Conventional sheets are made of natural fibers, mainly cotton, or are made of a blend of natural fibers and synthetic fibers, but in order to make them comfortable to use, it is necessary to starch them when washing them. After applying it, it is ironed to give it a crisp finish. Sheets that are simply starched and dried after washing remain wrinkled and look unsightly, and also feel rough when used, which means they are not comfortable to use. On the other hand, sheets that are dried and ironed without being starched during washing have no wrinkles and look good, but they lack a crisp feel and tend to wrinkle immediately after use.

[Problems to be Solved by the Invention] The purpose of the present invention is to provide a method that does not have the problems of the prior art described above, does not impair the texture suitable for sheets, and can achieve a crisp finish by simply ironing without gluing during washing. To provide sheets that are comfortable to use and do not wrinkle easily when used.

[A Thousand Steps to Solve the Problems] The object of the present invention is to use a polymer made of a high softening point polyester having a softening point of 240"C or more as a core component, and a low softening point polyester having a softening point of 10 to 180"C. A sheet made of spun yarn containing 3 to 20% short fibers of a bicomponent composite fiber, in which the sheath component has a thickness of 0.5 to 5μ and covers 60% or more of the periphery of the core component. This can be achieved by

The present invention will be explained in more detail below.

The high softening point polyester that constitutes the core component of the present invention is:
The target is polyethylene terephthalate, which has terephthalic acid or its ester as a dicarboxylic acid component and ethylene glycol as a glycol component, but it may also be one in which a small amount of a third component is copolymerized or blended.

The high softening point polyester needs to have a softening point of 240°C or higher. If the softening point is less than 240° C., the thermal deterioration of the polymer during spinning is large, resulting in a decrease in strength and elongation of the resulting undrawn yarn, resulting in poor spinnability and drawability.

The low softening point polyester constituting the sheath component of the present invention is:
Examples include polyesters whose main components are polyalkylene terephthalate and polyalkylene isophthalate.
Among them, the former polyester has terephthalic acid as the main acid component and alkylene glycol components having 2 to 6 carbon atoms, that is, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, and hexamethylene glycol as the main glycol components. It is a polyester copolymerized with 50 mol% or less of the components. Examples of the third component to be copolymerized include isophthalic acid, adipic acid, sebacic acid, glycolic acid, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The softening point of the low softening point polyester needs to be 70 to 180°C. If the softening point is less than 70°C, the melt viscosity of the polymer during spinning is too low, resulting in poor spinnability and complex abnormalities.If the softening point exceeds 180°C, the sheets may not be ironed. In this case, the adhesion between the two-component conjugate fibers and the blended fibers is poor, resulting in no crispy effect.

It is necessary to cover 60% or more of the periphery of the core component with a sheath component made of low softening point polyester. If it is less than 60%, there is insufficient adhesion when ironing.
Since the sheets will be uneven, the sheets will not be crispy.

The thickness of the sheath component surrounding the core component is 0.5 to 5μ.
It is necessary to do so. If the thickness of the sheath component is less than 0.5 μm, the adhesiveness during ironing will not be sufficient and the sheets will not be crisp. On the other hand, if the thickness of the sheath component is thicker than 5μ,
Not only does the spinning property deteriorate, but the texture of the sheets after ironing becomes rough and hard, which is not good.

The short fibers of the bicomponent composite fibers described above are blended with short fibers of cotton, hemp, or other synthetic W4 fibers to make a spun yarn, but in this case, the content of the bicomponent composite fibers must be 3 to 20%. . If the content is less than 3%, the adhesion between the two-component composite fibers and the blended fibers due to heating will be poor when ironing the sheets, making it impossible to obtain crisp sheets. Moreover, if the content exceeds 20%, not only will the unique feel of cotton or linen be lost, but also the adhesiveness due to heating during ironing will be too high, resulting in rough and hard sheets, which is not good. Two-component composite! Low softening point of fiber The content of composite fibers depends on the softening point of the polyester, the amount of surface coverage of the sheath component, the thickness of the core component, the size of the spun yarn, the properties of the fibers to be blended, etc. may be appropriately selected within the range of 3 to 20%, but the preferred content is 5 to 15%.

In the present invention, the low softening point polyester of the polymer constituting the sheath component may be polyethylene terephthalate copolymerized with 30 to 50 mol% of isophthalic acid in order to produce a crispy effect when sheets are ironed. preferable.

In this way, when copolymerizing isophthalic acid, if the copolymerization rate of isophthalic acid is less than 30 mol%, the fluidity of the polymer when heated is too low, so when ironing sheets, the inside of the blended yarn is The adhesion between two-component composite fibers or other blended fibers tends to be poor, and if the content exceeds 50 mol%, the softening point will not be lowered, resulting in lower adhesion efficiency between fibers and difficulty in handling during spinning. This tends to lead to increased costs, decreased fiber strength, etc.

In the present invention, it is preferable that the low softening point polyester has low crystallinity, with an endothermic heat absorption amount measured by DSC of 2 cal/g or less. If the endothermic heat amount is greater than 2 cal/Q, the adhesiveness tends to be poor.

In the present invention, the intrinsic viscosity of the low softening point polyester is 0.
．． It is preferably 60 or less, more preferably 0.55 or less. When the intrinsic viscosity exceeds 0.60, the viscosity of the polymer is high, so the fluidity of the polymer due to heating during ironing tends to decrease, and the adhesion between fibers tends to deteriorate. The intrinsic viscosity of the high softening point polyester is preferably 0.55 or more, and 0.55 or more. More preferably 60 or more.

If the intrinsic viscosity is less than 0.55, the spinning properties tend to deteriorate, and the spinning properties and weaving properties also tend to deteriorate.

In the present invention, the composite fiber type may be a complete core-sheath type in which the core component and sheath component are substantially concentric circles, or an eccentric core-sheath type in which the core component is uneven or partially exposed on the surface. It is preferable to use a core-sheath type bicomponent composite fiber.

In the present invention, the proportion of the core component in the two-component composite fiber is preferably 50% by weight or more. If the ratio is less than 50%, the tenacity of the fibers tends to decrease and the spinning properties and high-order processability tend to decrease, which is not preferable. The ratio is determined depending on the fineness of the composite w4N when the thickness of the sheath component is 0.
．． It is appropriately set within the range of 50% by weight or more so that it is in the range of 5 to 5μ.

The sheets of the present invention can be manufactured, for example, by the following method. First, short fibers consisting of two-component composite fibers are made of polyethylene terephthalate, which is copolymerized with 30 to 50 mol% isophthalic acid and has a softening point of 70 to 180°C and has an intrinsic viscosity U of 60 or less, as a sheath component. 24
Polyethylene terephthalate with an intrinsic viscosity of 0.60 or more is used as a core component, and the spinning temperature is 79-290°C and the spinning speed is 500-2500 m using a normal core-sheath composite spinning machine.
It is obtained by spinning, winding, and then drawing at a speed of 1/min, crimping, and cutting into short fibers. The thermal history from stretching to cutting is preferably set to a temperature below the softening point of the low softening point polymer.

The two-component composite 11 tons of short fibers produced in this way were
It is mixed with cotton at a rate of ~20% to make a spun yarn. The obtained spun yarn is machined, finished, cut, and sewn into sheets using conventional methods.

[Example] The present invention will be explained below with reference to Examples.

In addition, each characteristic value of polyester and polyester fiber in Examples was measured by the following method.

(Intrinsic viscosity) The fibers are dissolved in chloroform and separated into low softening point bollima and high softening point bollima. O-
This is a value measured at 25°C after dissolving in chlorophenol.

(Endothermic heat value) Generated between 70°C and 180°C when measuring io mg of sample at a heating rate of 16°C/min in a nitrogen atmosphere using a differential scanning calorimeter (Birkin Elmer Model DS04). It is absorbed by endothermic heat.

(Softening point of low softening point polymer) Lay two fibers together so that they intersect under a melting point microscope, raise the temperature at a rate of 1℃/min, and measure the temperature at which the two stacked fibers become one as the softening point. shall be.

(Softening point of high softening point polymer) When 10 mg of sample was heated at a rate of 16°C/min in a nitrogen atmosphere using a differential scanning calorimeter (Model DSC4 manufactured by PerkinElmer), the temperature was between 200°C and 260°C. The endothermic peak temperature that occurs in the softening point is defined as the softening point.

(Crispy Feeling) The crispy feeling was determined by sensory evaluation based on touch by five experts in texture evaluation. The crispness of a sheet made of 100% cotton spun yarn that was washed in a washing machine and dried was rated 1@, and the crispness of the sheet that was starched during washing, dried, and ironed was graded 5. The gluing strip A1 is as follows.

Thickening agent: “Shakit” manufactured by Lion Corporation (contains vinyl acetate fluorescent agent) Conditions: Sheets: 2 sheets for commercially available futons Water volume: 20 liters Thickening agent: 30 ml Stirring time: 5 minutes Example 1 Copolymerization of polyethylene terephthalate with an intrinsic viscosity of 0.65 and softening points of 235°C, 245°C and 250°C (measured by DSC) as a high softening point polymer, and isophthalic acid as a low softening point polymer in the range of 30 to 50 mol%. with an intrinsic viscosity of 0.55 and a softening point of 65℃, 75℃, 1
Polyethylene terephthalate at 05°C, 170°C and 190°C was heated to 10°C at a temperature lower than the softening point, respectively.
Drying under reduced pressure for a time, using the combinations shown in Table 1, using a high softening point polymer as a core component and a low softening point polymer as a sheath component, set the discharge amount so that the core/sheath ratio is 75/25, Melt spinning was carried out from a concentric ring composite type spinneret at a spinning speed of 1200 m/min to obtain an undrawn yarn of 365 denier and 36 filaments. The obtained undrawn yarn was drawn at a magnification of 3.4 times in a hot water bath at 80°C (80 m/min), crimped using a push-in crimp device, and dried with hot air at 80°C. Short fibers were produced by cutting into lengths of mm. The obtained Ili miscellaneous Q
! The fiber form was a complete concentric core M composite, and the sheath component had a thickness of 1 and a t of 1.2 μm. Further, the endothermic heat amount on the low softening point side measured by DSC was 2 cal/(7 or less), indicating that the material was substantially amorphous.

The resulting short fibers of the two-component composite m-fiber were blended with cotton fibers at a content of 10% to obtain a spun yarn, which was then woven into a plain weave and finished to obtain a sheet material. The sheets were ironed at a temperature of 5°C above the softening point of low softening point Borima. The results are shown in Table 1.

(The following is a blank space) Experiments Nα1, 3, and 6 in Table 1 are comparative examples for clarifying the effects of the present invention.

As shown in Table 1, Experiment NQ1 was conducted using a high softening point polymer (
The softening point of the core component (core component) is set to 235°C, which is lower than 240°C, resulting in poor spinability due to yarn breakage and winding around the take-up roller during spinning. Sexuality was also poor.

In experiment NQ3, the softening point of the low softening point polymer (HIi minute) was
The temperature was 65°C, which is lower than 70°C, and the spinnability, drawability, and high-order processability were poor as in Experiment Nα1. There was also a complex abnormality.

In experiment Nα6, the softening point of the low softening point polymer (sheath component) was set to 1
When the temperature was 190°C, which was higher than 80°C, the adhesion during ironing was poor and the crispness was low.

In contrast, experiments Nα2, 4, 5, and 7, which are examples of the present invention, had good spinnability, stretchability, and high-order processability, and the cotton texture remained crisp.

Example 2 A sheet fabric was obtained by processing under the same conditions as in Example 1, except that the fiber form of Example 1 was changed to an eccentric core-sheath type composite fiber.

The results are shown in Table 2.

(The following is a blank space) Experiment Nα8 in Table 2 is a comparative example for clarifying the effects of the present invention.

As shown in Table 2, in Experiment Nα8, the coverage ratio (%) of the sheath component to the core component was as low as 55%, and as a result, the crispness after ironing was poor.

On the other hand, in Experiment Nα9, which is an example of the present invention, the cotton texture remained the same and was crisp.

Example 3 In Example 1, as shown in Table 3, 7J[+E , got the sheet material. The results are shown in Table 3.

(The following is a blank space) Experiments Nα10, 13, 14, and 17 in Table 3 are comparative examples for clarifying the effects of the present invention.

As shown in Table 3, in Experiment Nα10, the thickness of the sheath component was as thin as 0.3 μm, so the adhesion during ironing was insufficient and the crispness was insufficient. In experiment Nα13, the thickness of the sheath component was as thick as 6 μm, so the spinnability and stretchability were poor, and the sheet after ironing was rough and hard.

In experiment Nα14, the content of composite m fibers in the spun yarn was as low as 2%, so the adhesion during ironing was insufficient and the crispness was insufficient. In Experiment No. 017, the content of composite fibers in the spun yarn was as low as 25%, so the adhesiveness during ironing was too high, resulting in a rough and hard yarn.

In contrast, experiments Nα11, 12, 15 in the present invention example
and No. 16 had a crisp texture with the same cotton texture.

[Effects of the Invention] The sheets of the present invention use a spun yarn made by blending a small amount of two-component composite fibers using low-melting point polyester as a sheath component, so that the sheets can have the same crispiness as if they had been starched by simply ironing them, without having to be starched during washing. It can be used in general households, but it is also particularly effective as a linen supply for inns and hotels.

Claims (4)

[Claims] (1) The core component is a polymer made of high softening point polyester with a softening point of 240°C or higher, the sheath component is a polymer made of low softening point polyester with a softening point of 70 to 180°C, and the thickness is 0.5 to 5 μm. A sheet made of a spun yarn containing 3 to 20% short fibers of bicomponent composite fibers in which a sheath component covers 60% or more of the periphery of the core component. (2) Low softening point polyester absorbs isophthalic acid from 30 to 5
It is a polyester copolymerized with 0 mol%, and the endothermic heat amount is 2.
The sheet according to claim (1), which has a cal/g or less. (3) The sheet according to claim (1) or (2), wherein the ratio of the core component to the two-component composite fiber is 50% by weight or more. (4) The sheet according to claim 1 or 2, wherein the low softening point polyester has an intrinsic viscosity of 0.60 or less, and the high softening point polyester has an intrinsic viscosity of 0.55 or more.