JP2006333936A - Biodegradable nonwoven fabric for pocket warmer-packaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide biodegradable nonwoven fabric for a pocket warmer-packaging material which has soft touch to the skin and fuzz preventing property and is easy to dispose of and does not harm natural environment because of almost complete biodegradation after use. <P>SOLUTION: The biodegradable nonwoven fabric for the pocket warmer-packaging material is made of aliphatic polyester filaments joined by partial thermocompression. The partial thermocompression rate of the nonwoven fabric is ≥5% and ≤20%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-woven fabric for biodegradable warmer wrapping material that is almost completely decomposed after use and is easy to dispose of. Particularly, it has both flexibility and surface fluff prevention property, and hot tackiness when making a warmer bag. The present invention also relates to an excellent non-woven fabric for biodegradable body packaging materials.

  A disposable body warmer is a heating element composition that generates heat in the air, wrapped in a non-woven fabric or paper laminated with a film such as polyethylene, and reacts with the oxygen in the air during use. It generates heat and is used in contact with the human body. For the film, a perforated film or a microporous film is used. In some cases, a non-porous film is laminated on a non-woven fabric and then subjected to perforation to give air permeability. The disposable body warmer is used in contact with the human body, and when used as a single film, the film is hard, so that the film is hard and the film is laminated to a non-woven fabric in order to prevent the sticking feeling peculiar to the film and the harsh skin feel. Yes. By adopting such a configuration, it is possible to give a cloth-like soft touch to the surface in contact with the human body and further prevent the bag from being torn.

  In recent years, under the protection of the global environment, resource recycling and dioxin problems have been actively pointed out, and even for disposable warmers, effective use methods and disposal methods that are friendly to the earth have been demanded. For example, Patent Document 1 discloses using the heating element composition after use as a fertilizer. However, the packaging material has to be discarded as it is, and it has not been sufficient from the viewpoint of protecting the global environment.

  Further, Patent Document 2 discloses a disposable body warmer using paper or natural fiber nonwoven fabric and a polylactic acid film. According to this method, since paper, natural fiber and polylactic acid film are biodegradable, environmental load can be reduced. There were problems in terms of strength during actual use, such as tearing, fiber falling off, and the surface being extremely fuzzy.

  In addition, long-fiber nonwoven fabrics made of polylactic acid polymers have been studied, and some are being put into practical use. However, the above-mentioned long-fiber non-woven fabric made of a polylactic acid polymer, which is being put into practical use, is rigid and inferior in flexibility. Therefore, in an application that touches the human body such as a disposable body warmer, the texture and the touch are poor. , Has a problem of rough feeling. Therefore, Patent Document 3 discloses that bending processing is performed in order to use a long-fiber nonwoven fabric made of a polylactic acid-based polymer for applications that touch the human body. As a result, a non-woven fabric with good touch could not be obtained.

JP 2001-137273 A JP 2003-250830 A JP 2002-105829 A

  The object of the present invention is to solve the above-mentioned problems of the prior art, to achieve both softness and softness and prevention of surface fluff, and because it is almost completely decomposed after use, disposal is easy and damages the natural environment. It is an object to provide a non-woven fabric for biodegradable body warmers and a disposable body warmer using the same.

  As a result of various studies to solve the above problems, the present inventors have achieved both a soft and comfortable touch feeling and a surface fluff prevention property, and sufficient bag making characteristics as a nonwoven fabric for disposable warmer packaging materials. In order to achieve this, it has been found that it is effective to specify the crystal structure of the aliphatic polyester polymer, particularly the recrystallization temperature, the partial thermocompression bonding rate of the nonwoven fabric, and the shape and pitch of the thermocompression bonding part. It came to an eggplant.

That is, the present invention is as follows.
(1) A non-woven fabric for a biodegradable warmer wrapping material, which is a partially thermocompression-bonded non-woven fabric comprising aliphatic polyester long fibers, wherein the non-woven fabric has a partial thermocompression bonding rate of 5% or more and 20% or less.

(2) The aliphatic polyester is a polymer of D-lactic acid, a polymer of L-lactic acid, a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, L- A copolymer selected from the group consisting of a copolymer of lactic acid and hydroxycarboxylic acid, and a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid, or a blend of two or more selected from the aforementioned polymers 2. The non-woven fabric for biodegradable warmer wrapping material according to item 1 above.

(3) The non-woven fabric for a biodegradable warmer wrapping material as described in 1 or 2 above, wherein the partial thermocompression bonding rate is 5% or more and 10% or less.

(4) The area of each thermocompression bonding part is 1 mm ² or less, and the product of the vertical pitch interval (mm) and the horizontal pitch interval (mm) of the thermocompression bonding part pattern is 10 mm ² or less. The non-woven fabric for a biodegradable body packaging material according to any one of the above items 1 to 3.

(5) The nonwoven fabric for biodegradable warmer wrapping materials according to any one of (1) to (4) above, wherein the nonwoven fabric has a non-bonding uneven portion in a pattern different from the thermocompression bonding portion.

(6) The biodegradable body packaging material according to any one of 1 to 5 above, comprising thin fibers having a fiber diameter of 0.1 to 6 μm and thick fibers having a fiber diameter of 5 to 18 μm. Nonwoven fabric.

(7) The non-woven fabric for biodegradable warmer wrapping material as described in 6 above, wherein a non-woven fabric composed of thin fibers having a fiber diameter of 0.1 to 6 μm and a non-woven fabric composed of thick fibers having a fiber diameter of 5 to 18 μm are laminated.

(8) A disposable body warmer using the non-woven fabric for biodegradable body warming material according to any one of items 1 to 7 on at least one surface.

  According to the present invention, it has a soft and soft touch, is not torn or fluffed even when it is used, and is biodegradable after use, thus reducing the burden on the environment. A disposable hand warmer can be obtained.

The present invention will be specifically described below.
Examples of the aliphatic polyester fibers constituting the long-fiber nonwoven fabric used in the nonwoven fabric for warmer wrapping material of the present invention include fibers made of the following thermoplastic resins. For example, poly (α-hydroxy acid) such as polyglycolic acid or polylactic acid or a copolymer containing these as main repeating unit elements can be mentioned. Also included are poly (ω-hydroxyalkanoates) such as poly (ε-caprolactone) and poly (β-propiolactone). Further, poly such as poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaprolate, poly-3-hydroxyheptanoate, and poly-3-hydroxyoctanoate (Β-polyhydroxyalkanoate) and copolymers of repeating unit elements constituting these and repeating unit elements constituting poly-3-hydroxyvalerate or poly-4-hydroxybutyrate. Also, polyalkylene dicarboxylates composed of a condensation polymer of glycol and dicarboxylic acid, such as polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, Examples include polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, and the like, or polyalkylene dicarboxylate copolymers having repeating unit elements constituting them. Furthermore, it is also possible to select a plurality of polymers having biodegradability here and blend them together.

  In the present invention, from the viewpoints of biodegradability, spinnability, practicality, and the like, a polylactic acid polymer can be preferably used particularly in the above. Examples of the polylactic acid-based polymer include poly (D-lactic acid), poly (L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, L- Any polymer selected from the group consisting of a copolymer of lactic acid and hydroxycarboxylic acid and a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid, or a blend thereof is preferred. Among these, a polymer having a melting point of 100 ° C. or higher can be preferably used. Here, as the hydroxycarboxylic acid in the case of a copolymer of lactic acid and hydroxycarboxylic acid, glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, etc. Can be mentioned. Of these, glycolic acid and hydroxycaproic acid are preferred.

  The molecular weight of the polylactic acid polymer is not particularly limited, but if the molecular weight is lowered, spinning becomes difficult, or even if spinning is possible, the strength of the obtained fiber is lowered. Further, when the molecular weight is increased, the processability is lowered and spinning tends to be difficult. Considering these points, the preferred weight average molecular weight is selected from the range of 10,000 to 1,000,000. A weight average molecular weight range of 30,000 to 500,000 is particularly preferred. In order to increase the degree of polymerization, the chain may be extended with a small amount of diisocyanate or tetracarboxylic dianhydride.

  A crystal nucleating agent may be added to the polylactic acid polymer. Examples of the crystal nucleating agent include talc, titanium oxide, boron nitride, calcium carbonate, magnesium carbonate, and carbon. When such a crystal nucleating agent is added, crystallization of the polylactic acid polymer is promoted, and heat resistance and mechanical strength are improved. Further, when spinning a polylactic acid polymer, it is possible to prevent fusion (blocking) between yarns in the spinning / cooling step.

  For the above reasons, the degree of crystallinity of the polylactic acid-based long fibers is preferably in the range of 10% to 40%. In order to achieve a crystallinity in this range, the amount of the crystal nucleating agent added to the polylactic acid polymer is 0.1 to 3.0% by mass, more preferably 0.5 to 2% by mass. 0% by mass. The crystallinity referred to here is obtained by obtaining a powdered long fiber (nonwoven fabric) by a Roland method using a wide-angle X-ray diffraction pattern. When the crystallinity of the fiber is less than 10%, the effect of improving heat resistance and mechanical strength is small. When the degree of crystallinity exceeds 40%, not only the flexibility as a fiber is poor and the spinnability is inferior, but also the decomposition rate during the composting process may be remarkably slow.

  In addition to the crystal nucleating agent, the polylactic acid-based polymer is easily plasticized by a plasticizer. Therefore, a plasticizer may be included in order to obtain an appropriate texture and flexibility. Plasticizers include phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzine phthalate, diisodecyl phthalate, ditridecyl phthalate and diundecyl phthalate, isophthalic acid derivatives such as diisooctyl phthalate, di -Adipic acid derivatives such as n-butyl adipate and dioctyl adipate, maleic derivatives such as di-n-butyl malate, citric acid derivatives such as tri-n-butyl citrate, itaconic acid derivatives such as monobutyl itaconate, butyl oleate, etc. Oleic acid derivatives, ricinoleic acid derivatives such as glycerin monolysylate, low molecular weight compounds such as phosphate esters such as tricresyl phosphate and trixylenyl phosphate, triacetin (glycerin triacetate) Acetic acid derivatives and the like, as well as the degree of polymerization from 2 to 10 approximately lactic acid oligomer, polymeric plasticizers such as polyethylene adipate and polyacrylate. Among the plasticizers, preferable plasticizers include triacetin and lactic acid oligomers having a polymerization degree of 2 to 10. The plasticizer content is preferably 1% by mass to 35% by mass, and more preferably 5% by mass to 15% by mass with respect to the polylactic acid polymer.

  Furthermore, various additives such as pigments, matting agents, colorants, and flame retardants can be added as necessary within the range not impairing the effects of the present invention. Moreover, it is preferable that the fiber which consists of the above thermoplastic aliphatic polyesters is the fiber which spun the polymer which knead | mixed the pigment etc. previously. When such an original fiber is used, since the pigment is preliminarily contained in the fiber, dyeing by post-processing is not necessary, heat deterioration due to dyeing is eliminated, and the number of steps is reduced, so that the cost can be reduced. Furthermore, good coloring can be obtained also for aliphatic polyester fibers which are difficult to be colored by dyeing after fiberization.

  The fiber form of the aliphatic polyester used for the nonwoven fabric for warmer wrapping material of the present invention is not particularly limited, and the aliphatic polyester may be used alone, or a composite using two or more aliphatic polyesters. Fiber may be used. In addition to the usual round cross section, the cross-sectional shape of the fiber includes a hollow cross section, an irregular cross section, a parallel composite cross section, a multilayer composite cross section, a core-sheath composite cross section, and a split composite cross section. An arbitrary fiber cross-sectional shape can be selected according to.

Long-fiber nonwoven fabric used in Cairo packaging material for the nonwoven fabric of the present invention, basis weight is preferably from ^{20g / m 2 ~100g / m 2} , more preferably from ^{30g / m 2 ~80g / m 2} , particularly preferably 40g / M ^{2 to} 70 g / m ² . When the basis weight is in the above range, the obtained nonwoven fabric for warmer wrapping material is excellent in flexibility, excellent in touch feeling, and sufficient strength is obtained when used as a disposable warmer.

  The long fiber nonwoven fabric used for the nonwoven fabric for warmer wrapping material of the present invention preferably has an average fiber diameter of 7 μm to 30 μm, more preferably 10 μm to 28 μm, and particularly preferably 12 μm to 18 μm. When the average fiber diameter is less than 7 μm, the fiber single yarn strength is reduced, fibrillated when touched, and adhesion of surface fluff and fiber waste occurs. Furthermore, the strength is low, tearing occurs during use, and the spinnability is also poor. When the average fiber diameter exceeds 30 μm, the strength increases, but the texture becomes rough when touched.

  The long-fiber nonwoven fabric used for the nonwoven fabric for warmer wrapping material of the present invention may be a single layer having the same fiber diameter, or may be a composite of two or more types of fibers having different fiber diameters. The fiber diameter is related to biodegradability. When the average fiber diameter is small, the degradation is quick, and when the fiber diameter is large, the degradation rate is slow. By combining fibers having different fiber diameters, the decomposition rate can be arbitrarily controlled. Furthermore, at the initial stage of decomposition, fibers having a small fiber diameter start to decompose, while thick fibers play a role of maintaining the strength of the nonwoven fabric for warmer packaging materials. In the middle of decomposition, thick fibers begin to decompose gradually, and eventually all of them are decomposed.

  The long fiber nonwoven fabric of the present invention is preferably a composite of a thin aliphatic polyester fiber having a fiber diameter of 0.1 to 6 μm and a thick aliphatic polyester fiber having a fiber diameter of 5 to 18 μm. The composite method may be any of mixed fiber, lamination, composite spinning, and the like. If the fiber diameter is thinner than 0.1 μm, the initial decomposition starts too early, and if the fiber diameter is larger than 18 μm, sufficient biodegradability cannot be obtained. Furthermore, the nonwoven fabric which consists of an aliphatic polyester long fiber nonwoven fabric with a fiber diameter of 5-18 micrometers and an aliphatic polyester fiber with a fiber diameter of 0.1-6 micrometers may be laminated | stacked. In particular, a structure in which a thick aliphatic polyester long-fiber nonwoven fabric having a fiber diameter of 5 to 18 μm is laminated on both sides of a non-woven fabric layer made of a thin aliphatic polyester fiber having a fiber diameter of 0.1 to 6 μm and bonded by heat fusion is as follows. This is preferable in terms of both biodegradability and strength. In addition, as a warmer packaging material, powder leakage prevention and concealment of the internal exothermic composition are also required, but due to the laminated structure of a fiber layer with a thin fiber diameter and a thick fiber layer, it prevents powder leakage. In addition, the concealability is improved, which is practically preferable.

The average apparent density of the long-fiber nonwoven fabric used in the nonwoven fabric for warmer wrapping material of the present invention is related to the flexibility and the thermal efficiency of the disposable warmer, that is, good thermal conductivity and heat retention, and is 0.1 g / cm ^{3 to} 0.3 g / Preferably it is cm ³ . If the average apparent density is less than 0.1 g / cm ³ , the texture is soft and the touch to the human body is good, but the gap between fibers becomes large, the thermal conductivity becomes excessive, and when it becomes a disposable body warmer, It generates heat and sufficient heat generation time cannot be obtained. On the other hand, if it exceeds 0.3 g / cm ³ , a high-density structure is obtained, the flexibility is insufficient, a paper-like texture is obtained, and the thermal conductivity is low, so that it becomes difficult to become warm as a disposable body warmer.

Below, the representative example of the manufacturing method of the long-fiber nonwoven fabric used for the nonwoven fabric for warmer packaging materials of this invention is demonstrated.
The long fiber nonwoven fabric used for the nonwoven fabric for warmer packaging materials of the present invention can be efficiently produced by a so-called spunbond method. That is, the above-described polylactic acid polymer is heated and melted and discharged from a spinneret, and the obtained spun yarn is cooled using a conventionally known cooling device, and then pulled by a suction device such as an air soccer. Refine. Subsequently, after the yarn group discharged from the suction device is opened, it is deposited on a moving deposition device such as a conveyor made of a screen to form a web. Next, the web formed on the moving deposition apparatus is partially subjected to thermocompression bonding using a partial thermocompression bonding apparatus such as a heated embossing roll or an ultrasonic fusing apparatus, whereby a long fiber spunbond nonwoven fabric is obtained. Obtainable.

  As the spun yarn, it is preferable to draw and thin at a high speed of 3500 m / min to 6000 m / min. If the pulling speed is less than 3500 m / min during pulling, the polymer does not progress in crystallization, and the mechanical properties of the obtained long-fiber nonwoven fabric are deteriorated or the wet heat shrinkage ratio is increased. If the pulling speed exceeds 6000 m / min, the spinnability may deteriorate rapidly and yarn breakage may occur.

  When the long-fiber non-woven fabric used in the non-woven fabric for a warmer wrapping material of the present invention is partially thermocompression bonded, the fiber gap constituting the long-fiber non-woven fabric can be reduced, and while maintaining a soft texture, It is effective in achieving both sufficient surface fuzz prevention properties. In the partial thermocompression bonding, a fused portion is formed that is uniformly dispersed throughout the nonwoven fabric by the above method. The partial thermocompression bonding rate is represented by the area ratio of the thermocompression bonding portion with respect to the entire long-fiber nonwoven fabric, and the partial thermocompression bonding rate is 5% to 20%, preferably 5% to 10%. When the partial thermocompression bonding rate is less than 5%, the flexibility is good, but the surface is fluffed by stagnation or the like, and the strength is not sufficient. When the partial thermocompression bonding ratio exceeds 20%, the surface fluff prevention property is excellent, but the texture is hard and the touch is poor.

The partial thermocompression bonding portion of the non-woven fabric for warmer wrapping material of the present invention preferably has an area of individual thermocompression bonding portions in the range of 0.09 to ¹ mm ² and the vertical pitch (mm) of the thermocompression bonding portion pattern. It is preferable that the product value of the pitch (mm) of a horizontal direction is the range of 0.45-10 mm < ² >.

When the area of each thermocompression bonding part exceeds 1 mm < ² >, the fuzz prevention property of a surface will improve, but the touch will become rough and bad. Also there is 1 mm ² or less, the vertical and value of the product of the lateral pitch of the pattern of the thermocompression bonded portions is greater than 10 mm ^2, but soft surface becomes soft ones, easily fuzz by such kneading, disposable As a warmer packaging material, there is a problem in surface strength.

On the other hand, if the area of the thermocompression bonding portion is smaller than 0.09 mm ² , sufficient thermocompression bonding cannot be obtained, and the nonwoven fabric does not exhibit sufficient strength. Furthermore, the convex part of the thermocompression-bonding roll has a very small area, pressure concentration occurs in the thermocompression-bonding part, and manufacturing is difficult, such as opening a hole. If the product of the pitch in the vertical direction and the pitch in the horizontal direction is smaller than 0.45 mm ² , the engraving of the thermocompression-bonding roll becomes very precise, and it becomes difficult to manage accuracy in manufacturing.

  Therefore, in order to achieve both the softness of the touch and the prevention of fuzz on the surface of the nonwoven fabric for disposable warmer packaging materials, the partial thermocompression bonding area and the pattern pitch are preferable.

  The important point in the production of the long-fiber nonwoven fabric used in the nonwoven fabric for warmer wrapping material of the present invention is to satisfy the specified partial thermocompression bonding rate, area, and pattern, and the shape of the so-called dotted crimping area is not limited at all. Is not to be done.

  In addition, it is preferable that the nonwoven fabric for warmer wrapping material of the present invention has a concavo-convex shaping portion in which fibers are non-bonding. By applying unevenness to the surface of the sheet, the waist becomes weak, the flexibility is improved and the touch is good without impairing the fluff prevention property of the surface.

  An uneven | corrugated shaping | molding part means having formed the convex part in the non-bonding recessed part different from the pattern of a thermocompression bonding part, and an opposite surface. The non-woven fabric is integrated on the front and back sides by interspersed partial thermocompression bonding portions, but the other portions have a soft feel of the fiber itself. The method of imparting a concave or convex deformation is, for example, between rolls having concave, convex or concave and convex patterns on the surface, and both of which are just mated, or a roll having a concave or convex pattern on one surface. It is common to press between flexible rolls or process between plates, but as a special method, the cloth is forcibly overfeeded between rolls with narrow gaps at a fixed rate, There is also a way of typing.

  The points to pay particular attention to in the conditions of concave or convex molding are the temperature during processing and the pressure applied to the cloth. The temperature at the time of treatment may be room temperature, but if necessary, raise the temperature within the range where fiber bonding and setting do not occur for the purpose of plasticizing by heating and making it easier to mold, or to stabilize the form. May be. Although the pressure at the time of processing varies depending on the temperature, it is naturally set to a pressure at which molding is sufficiently performed. In addition, although the fiber cross section of the compressed portion is deformed by performing this molding, it is also effective to perform a higher pressure treatment in order to obtain more flexibility due to this partial deformation effect. Of course, it is necessary to be careful not to cause temporary fixing of fibers or thermocompression bonding at the compression part. As a preferred embodiment of the present invention, it is preferable that the convex portion on one side forms a concave portion on the opposite surface. That is, for example, when the concave portion is continuous on one side, it is preferable to project from the other region so that the same portion becomes a convex portion on the other side.

  The nonwoven fabric for warmer wrapping material of the present invention has a crystallization temperature (Tc) when the temperature is lowered, and the temperature is preferably 100 ° C. or lower. Here, the temperature-falling crystallization temperature is a crystallization temperature measured by a differential scanning calorimeter (DSC) at a temperature-fall rate of 10 ° C./min. Tc is not particularly limited, but is preferably 100 ° C. or lower from the viewpoints of softness of touch and hot tack at the time of bag making.

  The present invention will be described below in more detail based on examples and comparative examples, but the present invention is not limited to these examples.

The measurement method and the evaluation method are as follows.
(1) Weight per unit (g / m ² )
Three test pieces each having a length of 20 cm and a width of 25 cm are sampled per 1 m width of the sample by the method prescribed in JIS L-1906, the weight is measured, and the average value is obtained by converting the mass per unit area.

(2) Thickness The thickness of a load of 10 kPa is measured by the method specified in JIS L-1906. The average apparent density (g / cm ³ ) is calculated from the basis weight and thickness by the following formula.
Average apparent density (g / cm ³ ) = (weight per unit area g / m ² ) / ((thickness mm) × 1000)

(3) Average fiber diameter (μm)
Samples of 1 cm square were sampled and photographs were taken with an electron microscope, 20 single yarn fiber diameters were measured from each photograph, and the average fiber diameter was calculated from the total average value. Here, the average fiber diameter means the diameter of the single yarn fiber in the case of a perfect circle single yarn fiber, and in the case of an irregular cross-section fiber, the single yarn in the case of a perfect circle from the cross-sectional area of the single yarn fiber cross section The value is converted to the fiber diameter.

(4) Partial thermocompression rate (%)
A 1 cm square test piece was sampled and photographed with an electron microscope. The area of the thermocompression bonding part was measured from each of the 20 photographs, and the total average value was taken as the area of the thermocompression bonding part. Moreover, the pitch of the pattern of the thermocompression bonding part was measured in the vertical direction and the horizontal direction. From these values, the ratio of the thermocompression bonding area per unit area of the nonwoven fabric was calculated as the partial thermocompression bonding rate.

(5) Crystallization temperature during temperature drop (Tc)
It measured with the temperature-fall rate of 10 degree-C / min with the differential thermal scanning calorimeter (DSC: DSC2920 by TA Instruments).

(6) Surface fluff prevention properties After laminating a 50 micron polyethylene (LLDPE) film on the non-embossed surface of the nonwoven fabric, it is perforated with a needle roll (about 6%) by a method well known to those skilled in the art, did. Use the resulting warmer packaging material as an upper layer, and use a non-woven fabric laminated with a non-porous film for the lower layer, overlay the film surface on the inside, fill it with the heating element composition, and heat the surroundings. Seal and make a disposable body warmer. The produced disposable body warmer was rubbed 100 times by hand, and the state of the surface fluff was visually determined.

○: No fuzz is seen on the surface of Cairo.
(Triangle | delta): Fluff is seen on the Cairo surface.
×: Cairo surface is fuzzy.

(7) Softness of touch A disposable body warmer was prepared in the same manner as in the evaluation of surface fluff prevention described above, and the softness of the touch of the surface was subjected to sensory evaluation.

◎: Very soft to the touch ○: Soft to the touch △: The touch is slightly hard and slightly stiff.
X: The touch is hard and it is stiff.

(8) Biodegradability Each non-woven fabric is cut into a 5 cm × 5 cm rectangle to form a sample, and each sample is placed in a commercially available household compost (food waste eater; manufactured by Matsushita Electric Works) at room temperature. The biodegradation rate was visually observed, and the sample shape after 30 days was evaluated.

○: The sample piece was broken into pieces.
X: The appearance change of the sample was not seen.

(Examples 1-3)
Using a 65 mm extruder, a polylactic acid (copolymerization ratio (molar ratio) of D-form / L-form = 1.3 / 98.7) thermoplastic resin is melted at a melting point of 170 ° C. and an MFR value of 10 g / 10 min. Extruded at a temperature of 215 ° C, spun filaments using a 1540-hole spinneret, pulled using a high-speed airflow traction device, and received on a wire mesh web conveyor with a moving suction device. Formed. The MFR value is a value obtained by measurement according to the condition 4 (test temperature 190 ° C., test load 21.18 N) in Table 1 of “Thermoplastic Plastic Flow Test Method” JIS K-7210.

  The obtained web was conveyed and partially thermocompression bonded at a linear pressure of 490 N (50 kg) / cm with a thermocompression bonding roll in which an engraving roll and a smoothing roll were combined to obtain a long fiber spunbond nonwoven fabric. Table 1 shows the physical properties of the obtained nonwoven fabric.

  The biodegradability of this nonwoven fabric was evaluated. Moreover, the disposable warmer was produced by the above-mentioned method using this nonwoven fabric, and surface fluff prevention property and the softness of the touch were evaluated. The results are shown in Table 2.

Example 4
A non-woven fabric for a warmer wrapping material was obtained in the same manner as in Example 1 except that non-bonding uneven shape molding was performed after partial thermocompression bonding of the long fiber spunbonded nonwoven fabric. The obtained nonwoven fabric for warmer packaging materials was evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.

In addition, the uneven shape molding is a continuous linear honeycomb-shaped pattern (tortoise shell concave pattern) with a side of 0.9 mm and a line width of 0.1 mm (pressing area ratio of 12.5%, pattern pitch length of 2.8 mm, width of 3.2 mm, The pattern was pressed between a embossing roll (depth of 0.7 mm) (100 ° C.) and a rubber roll having a surface hardness of 50 degrees (JIS-A hardness) and pressing the handle at a linear pressure of 980 N (100 Kg) / cm. A very flexible non-woven fabric was obtained in which the periphery of the turtle shell was pressed and the fibers became non-bonded concave portions, and the central portion was raised and convex.

  The disposable warmers produced using the nonwoven fabrics for warmer wrapping materials of Examples 1 to 4 were all soft to the touch and good in preventing fluffing.

  Further, after laminating a 50-micron polylactic acid film on the anti-embossed surface of the nonwoven fabric for warmer wrapping materials of Examples 1 to 4, perforation (about 6%) with a needle roll by a known method, did. Using the obtained warmer packaging material as an upper layer, the lower layer uses a non-woven fabric laminated with a non-porous polylactic acid film, the film surface is overlapped inside, and the heating element composition is filled therein, Was heat sealed to produce a disposable body warmer. Since it was formed with a nonwoven fabric and a film made of thermoplastic aliphatic polyester fibers having biodegradability, it was completely decomposed quickly when discarded in soil, and no disposal treatment was required.

(Comparative Examples 1 and 2)
A non-woven fabric for a warmer packaging material was obtained in the same manner as in Example 1 except that the area of each thermocompression bonding portion and the pitch of the pattern of the thermocompression bonding portion were changed to make a non-woven fabric having different partial thermocompression bonding rates. The obtained nonwoven fabric for warmer packaging materials was evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2.
As can be seen from the table, the obtained non-woven fabric for warmer wrapping material has a high partial thermocompression bonding rate.

(Comparative Example 3)
A polyethylene terephthalate thermoplastic resin having a melting point of 256 ° C. and [η] = 0.71 was extruded at an extrusion temperature of 300 ° C., and a filament group was spun out using a 1540-hole spinneret. After that, the web was prepared in the same manner as in Example 1 to obtain a long fiber spunbonded nonwoven fabric. [Η] is the intrinsic viscosity, and the intrinsic viscosity [η] is a value obtained based on the following definition formula.
[η] = lim (η _r −1)
C → 0
In the formula, η _r is a value obtained by dividing the viscosity at 35 ° C. of a polyethylene terephthalate solution dissolved in o-chlorophenol having a purity of 98% or more by the viscosity of the solvent itself measured at the same temperature, and the relative viscosity. Is defined as C is the mass value of the solute in units of grams in 100 ml of the above solution.

  Using the obtained long fiber spunbond nonwoven fabric, a nonwoven fabric for warmer packaging material was obtained in the same manner as in Example 1. The obtained nonwoven fabric for warmer packaging materials was evaluated in the same manner as in Example 1. The results are also shown in Table 1 and Table 2. In this comparative example, polyethylene terephthalate having no biodegradability was used as a constituent fiber, so that it was not decomposed on the soil surface, and disposal was necessary after use.

  The nonwoven fabric for warmer wrapping material of the present invention has a good touch and excellent anti-fluff property, and is almost completely decomposed after use, so that it can be easily disposed of and does not damage the natural environment. Therefore, it can be used suitably for a disposable body warmer. It can also be used in hot compresses and rice cake tools.

Claims (8)

  A non-woven fabric for a biodegradable warmer wrapping material, characterized in that it is a non-woven fabric made of aliphatic polyester continuous fibers and subjected to partial thermocompression bonding, wherein the non-woven fabric has a partial thermocompression bonding rate of 5% or more and 20% or less.   Aliphatic polyester is a polymer of D-lactic acid, a polymer of L-lactic acid, a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, L-lactic acid and hydroxy It is a polymer selected from the group consisting of a copolymer of carboxylic acid and a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid, or a blend of two or more selected from the above polymers. The non-woven fabric for a biodegradable warmer wrapping material according to claim 1.   The non-woven fabric for biodegradable warmer wrapping material according to claim 1 or 2, wherein the partial thermocompression bonding rate is 5% or more and 10% or less. The area of each thermocompression bonding part is 1 mm ² or less, and the product of the vertical pitch interval (mm) and the horizontal pitch interval (mm) of the thermocompression bonding part pattern is 10 mm ² or less. Item 4. The nonwoven fabric for biodegradable warmer packaging material according to any one of Items 1 to 3.   The non-woven fabric for a biodegradable warmer wrapping material according to any one of claims 1 to 4, wherein the nonwoven fabric has a non-bonding uneven portion in a pattern different from partial thermocompression bonding.   The nonwoven fabric for biodegradable warmer packaging material according to any one of claims 1 to 5, comprising thin fibers having a fiber diameter of 0.1 to 6 µm and thick fibers having a fiber diameter of 5 to 18 µm.   The nonwoven fabric for biodegradable body warmers according to claim 6, wherein a nonwoven fabric made of thin fibers having a fiber diameter of 0.1 to 6 µm and a nonwoven fabric made of thick fibers having a fiber diameter of 5 to 18 µm are laminated.   A disposable body warmer using the nonwoven fabric for biodegradable body warming material according to any one of claims 1 to 7 on at least one surface.