KR920007728B1 - Heat-shrinkable elastomer method of producing the elastomer and articles utilizing the elastomer - Google Patents

Abstract

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Description

Heat-shrinkable elastomer and method for producing a product using the elastomer

1 is a block diagram showing a machining process of the present invention.

2 is a schematic plan view of a portion of a continuous diaper web in manufacture with a ribbon of the film of the present invention shown prior to attachment to a waist band and heat shrink.

3 is a schematic view of an apparatus for co-extrusion of an embodiment of a multilayer film of the present invention.

* Explanation of symbols for main parts of the drawings

10 extruder 12 film

14 roll 16: drawing machine

The present invention relates to heat shrinkable elastomers, more particularly heat shrinkable elastomers, which are particularly useful for forming elastic pleats in garments such as disposable diapers or incontinence articles.

Forming elastic pleats in selected areas of the garment is necessary or necessary to adhere the garment to the wearer's body, such as the waist or wrist. Such pleats are particularly necessary in the case of disposable garments, including plastic garments such as disposable diapers. That is, the present invention will be described with respect to its background and some best practice, especially with regard to disposable diapers or incontinence garments, but the present invention may be applied to other garments such as gowns, masks, shoe covers, and the like. I can understand.

The shape of a disposable diaper is usually a "solid" or a general "I". These disposable diapers are produced from a sheet of continuous web and absorbent bats that are treated inside and outside, wherein each waist band portion of the diaper module is integrally connected to the waist band portion of the adjacent diaper module (see FIG. 2). . Individual diapers are formed by cutting the continuous web at a waist band portion transverse to the travel direction of the web. That is, the waist band is cut in the cross machine direction.

Disposable diapers have also been commercially applied to apply elastic materials to leg bands. However, when trying to attach the elastic material to the waistband of the diaper having the elastic material attached to the leg band, a large production problem occurs. For example, if the tension is maintained in the leg band direction, the elastic body attached to the waist band wrinkles the diaper and interferes with the folding process, packaging process or other production processes. No commercial solution to this is currently known.

Recently, thermally stable heat shrinkable elastomeric materials used to form wrinkles in disposable garments, such as disposable diapers or hospital gowns, as demonstrated in US Pat. Nos. 3,912,565, 3,819,401, 3,639,917. Several proposals have been made for.

US Patent No. 3,912,565 to Koch et al. And US Patent No. 3,819,401 to Massengale et al. Disclose a method of preventing premature shrinkage by heating, stretching and cooling flexible polyurethane and plastic vinyl chloride sheet materials, respectively. It is described. To prevent premature shrinkage, the elastomeric sheet material is reheated to allow for limited relaxation and the sheet material is cooled to heat set. Subsequently, when the heat-fixed sheet material is applied to the product and heat is applied, the product shrinks to its original length and wrinkles are formed in the product. As is more fully described in connection with the first degree of the United States patents of Koch et al., Maestrole et al., The sheet material is stretched between the heated rolls 25 and the nip rolls 31, 33 and then cooled. It is then partially relaxed in the heated bath 45 and collected in the roll 49. It should be noted that U.S. Patents, such as Koch et al. And Maesin Gale, draw an extension by external heating, cool it in an elongated state, and then reheat it again by external heating to achieve controlled heat shrinkage.

U.S. Patent No. 3,639,917 to Althouse et al. Describes an elastomer composed of a heat shrinkable convex copolymer. According to Althaus, the convex copolymer is stretched or deformed from its original length at high temperatures to form a new length and then cooled to keep the copolymer at the new length in the stretched state. Thus, the copolymer of althouse is maintained at the new length by cooling until shrinkage occurs to its original length upon heating. Therefore, the copolymer of althouse is drawn from the original length to the new length by stretching, to maintain the new length by cooling, and then returned to the original length by heating.

The elastic body of the present invention, which exhibits potential elastic energy that can be recovered during heat-shrinkage, is stretched or rolled in one direction without being subjected to external heat treatment and is oriented in a constant length, so that the elastic body is removed when the applied tension is removed. Is relaxed to a permanent strain length that is longer than the original length but shorter than the drawn length. In particular, the original or minimum length of the heat shrinkable elastomer is elongated to substantially longer or second length in one direction, for example about 200% or more, without external heating treatment. Upon relaxation, the elastic body is permanently deformed to any third or intermediate length between the original length and the second length. This third length or intermediate state may be known as a reserve type. Tensioned elastomers, including these preforms, exhibit reduced elastic properties while in the deformed state. In the subsequent heat treatment, the elastic body contracts, restoring or restoring its elastic properties. When an actual or desired level of tension is applied, the elastomer exhibits an increase in tension with an increase in the permanent strain length, while a conventional elastomer exhibits minimal permanent strain.

It is important to eliminate the thermosetting and cooling processes of the elastomeric preforms. Naturally, the tensioning of the elastomer or the relaxation of the elastomer, which results in the uniaxial orientation of the polymer, can be achieved at room temperature or at ambient temperature [eg, 21.1-23.9 ° C. (70-75 ° F)] without external heat treatment, ie even if the internal temperature rises. Is performed in However, the elastic body retains its heat shrink characteristic. Therefore, the commercial application of the elastic body to the garment eliminates the need for a constant machining process and associated apparatus.

According to a preferred embodiment of the present invention, the elastomer is coextruded or laminated with the inelastic body. The elastic body is preferably extruded at the same time according to a known technique to form a composite sheet. This composite is preferably composed of three layers, one intermediate elastic layer and two outer layers. This elastic body can exhibit adhesiveness and can form a compression ingot when set up in roll form. The surface layer of inelastic material is chosen to not block or relax if the material is not rolled, which facilitates processing steps such as guiding, cutting and placing. In addition, the elastic body of the present invention may have no or weak adhesion to a plurality of garment materials. Therefore, the outer layer located in the opposite direction of the composite that faces the garment is attached to the garment by a dark or heat sensitive adhesive. Thus, the composite has this advantage of not having a single layer composite at all.

1. State of implementation of monolayer film

According to FIG. 1, the process of the present invention is to mold the film 12 starting with the extrusion of a polymer which may be pelletized by means of a conventional extruder 10, which is then preferably rolled onto a roll 14 It can be seen that it is stored and transferred to the next process, the film stretching machine. The thickness of the extruded film is advantageously between about 0.005 cm (2 mil) and about 0.010 cm (4 mil), but the thickness varies depending on the amount of stretching required to achieve the desired degree of wrinkles, the type of polymer used, the production, and the like. It is also possible to make it.

Although the term “film” has been used in the foregoing, the elastic body of the present invention may be produced in a structure such as a ribbon, thread, tape, or the like. However, for convenience of illustration, the term “film” will be used below.

As briefly mentioned above, the polymer used to produce the film according to the present invention is preferably a block copolymer having alternating segments of polyamide and polyether block polymer by the above general formula.

Wherein R ₁ represents a polyamide polymer block such as nylon 6, nylon 6, 6, nylon 10, nylon 11 and nylon 12, and R ₂ represents a polyethylene glycol polypropylene glycol, and polytetramethylene glycol A polyether polymer block, n is an integer.

Copolymers as described above are available from Rilsan Corp., Glen, NJ under the trade name PEBAX. Particularly preferred among the films of the present invention are PEBAX extruded grades 2533 and 3533.

As already explained, the formed film 12 is then uniaxially stretched without external heat treatment by a conventional film stretching machine 16 such as by automatic speed roll processing. A particularly good differential speed roll for use as the film stretcher 16 for stretching the film of the present invention is the Marshall and Williams Model D 7700 drinking direction stretching apparatus. According to the known principle of differential roll stretching, the film 12 is uniaxially stretched due to the differential speeds of the low and high rolls. Another orientation method to induce thermal shrinkage is to “cold roll” on multi-stack rolling mills under an external pressure similar to that used to roll metal foil sheets such as aluminum foil. will be. However, a general phenomenon that occurs regardless of the orientation method, is that the thickness is increased and correspondingly, the size is increased in the orientation direction.

Conventional uniaxially stretched polymer films are generally preheated to or above the secondary phase transition temperature. The conventional film is then stretched under such elevated temperatures and then cooled while maintaining the stretched state. This preheating process is important to ensure proper stretching and orientation for conventional films.

However, the present invention does not require preheating at all. If a differential speed roll is used to stretch the film 12, some heat may be generated, especially due to frictional forces, during the uniaxial stretching process of the film 12, but such a temperature causes strain relaxation of the copolymer film. Significantly lower than the temperature at which it begins to be produced (eg, substantially below about 78.9 ° C. 175 ° F.). That is, even if some heat is generated due to friction during film stretching, the temperature reached by the film of the present invention is substantially lower than the temperature at which strain relaxation occurs. Of course, thermosetting is intended that the temperature should be at or above the temperature at which strain relaxation begins to occur. (See, US Patent No. 3,912,5656, Column 3,28-38). Therefore, the thermosetting of the oriented film of the present invention is not necessary at all as opposed to the conventional way of thinking which is essential in the art.

The uniaxial stretching amount of the elastomeric film according to the present invention is important for achieving a suitable shrinkage rate and thus forming wrinkles in a product using the film. According to the present invention, uniaxial tensioning is carried out so that the film can be drawn to an elongated length significantly longer than the length at which permanent deformation takes place. Upon removal of the applied tension, the film naturally relaxes to a length longer than the original length corresponding to the amount of permanent strain imparted thereto (eg without being induced to relaxation by heat treatment). Thus, the length difference between the permanent strain length and the original pre-stretched length is used for heat shrink. Therefore, when heat is applied (eg, about 78.8 ° C. or higher), the stretched film will have more relaxation and shrinkage. That is, most of the length difference of the stretched film between the original length and the permanent strain length is present as a permanent strain that can be recovered when applying heat.

The film of this invention is uniaxially stretched so that the elongation of a film may be about 200 to 700% per unit length. It has been found that when the film of the present invention is uniaxially stretched within this range, the film exhibits some natural relaxation with the removal of the stretching force, but such relaxation will not proceed below each permanent deformation length. The length of the film corresponding to the amount of permanent deformation imparted to the film depends on the amount of uniaxial tension applied to the film. However, for uniaxial stretching in the range of about 200 to 700%, the permanent strain length is about 20 to 60% of the stretched length of the film. That is, when stretched at about 200 to about 700% (when stretched 3 to 8 times the original length), the amount of permanent deformation applicable to heat shrinkage is from about 20 to about 60% of the stretched length of the film.

Therefore, the amount of permanent deformation imparted to the film of the present invention will determine the degree of heat shrinkage applicable to properly wrinkle the part of the product concerned. Permanent deformation between about 20-60% of the elongated length (“no limiting shrinkage”) is about 30 when the uniaxially stretched film is attached to a portion of a flexible garment, such as the waistband of a disposable diaper. We found that it was beneficial to transform it so that a contraction between -45% (constricted contraction) occurred. In other words, because flexible products interfere or limit the shrinkage of the film to some extent, no complete return to the original pre-stretched film length occurs during heat shrink. Nevertheless, when the film of the present invention is uniaxially stretched as described above (eg, a permanent strain or elongation of about 20-60% based on the final elongation at which the film is processed), the desired wrinkle formation of the product occurs. .

In stretching, the film of the present invention is conventional in accordance with the permanent direction (ie parallel to the uniaxial stretching direction) to form a ribbon having a width of 0.95 cm to 1.27 cm (of course, other widths are possible depending on the application purpose). The film is slit by the film slitting device 40. The ribbon can be wound tightly around the film for use in the diaper production device 42 according to known methods.

The ribbon is cut to the required length (about 15.24 cm is preferred), but is still in the heat-shrinkable stretched state, and the diapers 54, 56 as the connected web 60 proceeds in the machine direction (figure 2 arrow 57). It is adhesively fixed to the waist band portion 50, 52 of the). Suitable adhesives for bonding the ribbon of the film of the present invention to the waist band portion of the diaper are H. ratio. It is marketed as HL-1307-33-1 by H. B. Fuller Co. and X807-378-01 by Findley Co. A particularly preferred device for cutting a ribbon to a predetermined length and adhering it to the waist bad portion of the diaper is described in a US patent application filed under the name of “To attach a elastic waist band to a disposable diaper” of Thorson.

At present, the stack or folded diaper (which is preferably 8 to 10 diapers per stack) with the ribbon of the heat-shrinkable insulator film of the present invention is heat treated all at once by a suitable heat-shrinkage device 44 to obtain the ribbon. It is thought that heat shrinkage occurs and thus wrinkles occur in the waist band of the diaper. Thermal shrinkage of ribbons in diaper stacks, such as “formation of elastic garments in garments and other products” and the like. In this way, due to premature machine gathering or pleat formation of the waist band, there is no disturbance in the diaper folding equipment.

2. State of implementation of plural films

Another embodiment of the present invention is inelastic polymers such as ethylene vinyl acetate (EVA), EVA ionomers (Plexar 3, Plexar 102 and Surlyn 1702, etc.) and polyethylene to produce heat-shrinkable but still tactile films And co-extrusion of the polyether / polyimide copolymer.

[Plexar 3 and Plexar 102 can be obtained from Chemplex Corporation, but Surlyn 1702 can be obtained from DuPont.] Skin suitability of the elastic waist band is preferred when the film of the present invention is used as a waist band for disposable diapers. According to this embodiment of the invention, the polyether / polyamide copolymer is coextruded as the outer layer of the core or inelastic polymer with the surface exposed layer. The outer layer may not be heat shrinkable, but this outer layer does not affect the heat shrinkage of the core to such an extent that the core layer film does not cause proper wrinkle formation in the garment due to the excellent heat shrinking ability.

Co-extrusion of various polymer layers or thermoplastic material layers is known as generally illustrated in US Pat. No. 3,557,265 to Chisholm et al. And US Pat. No. 3,479,425 to Lefevre et al. Co-extrusion of the various polymers is performed using a single manifold die or multiple manifold co-extrusion dies equipped with a mixing adapter to enable melt lamination of multiple layers of dissimilar polymer materials. One particularly preferred mixed adapter that can be advantageously used to produce the coextruded film of the present invention is described in US Pat. No. 4,152,387 to Chloe et al.

A conventional method of making coextruded multilayer films of the present invention is shown in FIG. As shown in the figure, the inelastic outer layers 70 and 72 are formed by melt extruding the inelastic polymer 74 by an extruder 76. In a similar manner, elastic core layer 80 is formed by extruder 84 by melt extrusion of elastomer 82 (eg, PEBAX extrusion grade 2533 or 3533 is preferred). The melt extruded polymers 74, 82 are then passed through the conduits 78, 88 to the mixing adapter 90, respectively. As schematically shown in the figure, the elastomer 82 is melt laminated by an inelastic polymer 74 so that a sandwich between the outer layers 70, 72 of the inelastic polymer 74 is the core of the elastomer 82. Form layer 80.

) 동시 압출에 의한 것이다. 이어서, 상기 동시 압출 필름은 통상적인 연신기(16)에 의하여 배향될 수 있고, 슬릿팅 장치(40)에 의하여 리본으로 슬릿되고, 기저귀 제조 장치(42)에서 기저귀에 가해지고, 제1도에 기재된 열수축 장치(44)에 의하여 열수축될 수 있다.The temperature of the mixing adapter 90 depends on the polymer used, but is preferably between about 182.2 ° C. (360 ° F.) and about 260 ° C. (500 ° F.) [preferably about 204.4 so that the coextruded film of the present invention is preferably formed. It is advisable to maintain a temperature of 400 ° F. Different thicknesses may be used depending on the desired final thickness, but the total thickness of the coextruded film is about 0.005 to 0.013 cm (about 2 to 5 mil), particularly preferred. Preferably between about 0.005 and about 0.010 cm (about 2 to about 4 mils) The coextruded film is in contact with the cold rolls 92 and 94 and is cooled to substantially maintain the extrusion thickness of the film. Another means for forming is blown using an annular die having a coaxial flow path corresponding to each layer of the composite (

) By co-extrusion. The co-extruded film can then be oriented by a conventional stretching machine 16, slit by ribbon by the slitting device 40, applied to the diaper in the diaper making device 42, and shown in FIG. 1. Heat shrink by the heat shrink device 44 described.

The core layer of the elastic polyether / polyamide block copolymer is preferably the main component (based on the weight percent of the illustrated extruded film) present in the resulting coextruded film. Therefore, the core layer is present in an amount of about 70 to 90% by weight in the coextruded film with a substantially evenly distributed balance between each outer layer.

The behavior of coextruded composites or laminates of the present invention is similar to that of the single layer films described above. That is, where the composite is uniaxially oriented at a length between about 200 and about 700% of its original length, permanent strain is usually imparted to a length that differs from about 20 to about 60 weight percent of the stretched length. When the tension is removed, the coextruded film likewise relaxes naturally (eg, without heating) to a length that exhibits imparted permanent strain (eg, permanent strain length). That is, the length difference between the stretched length and the permanent strain length is effective as the shrinkage length, so that when the film is subjected to heat (generally around 78.9 ° C.), the film is substantially relaxed and shrunk to restore elastic properties. do.

As described briefly above, the outer layer or the cortex of the composite tends to somewhat interfere with the heat shrink of the entire film due to the inelastic properties of the cortex. However, such disturbances are not such as to interfere with the heat shrinkage of the composite. Since the outer layer is inelastic, at the same time such outer layer is permanently deformed by uniaxial tensioning of the extruded film. However, the entire coextruded film continues to relax on its own by up to about 20-60% elongation once the tension is removed due to the presence of the elastic core layer.

The inner laminate bond strength between the outer layer and the core layer is preferably at least 47.2 g / cm (120 g / in) to ensure that the layers remain laminated to each other when coaxially oriented to an elongation of about 700% or less.

It is also possible to use microwave energy as a device for thermally shrinking both monolayer and multilayer films of the present invention. It has been found that when the elastomer of the present invention is exposed to 2450MH _Z and 3-6 kilowatts of microwave energy for about 5-10 seconds, adequate heat shrinkage occurs. In other words, upon exposure to microwave energy, the elastomer shrinks to about 20-60% of the stretch length. For example, the specific heat-shrinkable elasticity of the present invention consists of a core layer of PEBAX extrusion gold 3533 co-extruded with the outer layer of Plexar 102 and uniaxially stretched four times its original length to give a ribbon thickness of 0.0038 cm (1.5 mil). The ribbon exhibited a heat shrinkage of at least 20% when attached to the waist band portion of the diaper when the ribbon-attached diaper was exposed to microwave energy of 2450MH _Z and 3-6 kilowatts for about 5-10 seconds.

The following examples further illustrate the invention. However, the present invention is not limited to these examples.

Example 1

Approximately 61 cm / sec (120 fpm) for 0.005 cm (2 mil) and 91.44 cm for line speed of approximately 30.5 cm / sec (60 fpm) for 0.010 cm (4 mil) at 204.4-215.1 ° C (400-425 ° F) Monolayer films were prepared from various commercially available polymers by cold rolling using a (36 inch) injection die. The thermal shrinkage of the film sample was tested by making a 2.54 cm × 25.4 cm (1 inch × 10 inch) strip cut in the machine direction. This film sample was then marked at an initial length of 10.16 cm (4 inches) and adjusted for 24 hours at a relative humidity of 55% and a temperature of 70 ° C. Following adjustment, each sample was tested in an Inston tension tester at 22.2 ° C (72 ° F) and 55% relative humidity at 100%, 300% and 500% elongation (e.g., 2, 4 and 6 times elongation). Stretched. The initial jaw width for the Instron tension tester was approximately 11.43 cm (4.5 inches), which was 22.86 cm (9 inches) at 100% elongation, 45.72 cm (18 inches) at 300%, and 68.58 cm (27) at 500%. Inch) film sample length. Elongation in each case was 1000 mm / min. The stretched sample was again adjusted for 24 hours at about 22.2 ° C. (72 ° F.) and 55% relative humidity.

Permanent strain was then measured as a percentage of the original 10.16 cm (4 inch) length according to the following equation.

In the above formula, L _O represents the original film length, and L _F represents the final length after which the film is relaxed without heat treatment after removing the tension applied to the film.

Subsequently, in order to measure the heat shrinkage applied to the film, the stretched film sample was subjected to heat shrinkage by treating at 78.8 ° C (175 ° F) for 5 seconds. The length (Lf ₁ ) of each film sample following the heat shrinkage was measured, and the heat shrinkage rate was calculated by the following equation.

In the above formula, Lf represents the length of the film as described above in relation to the percentage of permanent deformation.

In order to measure the elasticity characteristics of the heat shrinkable material, the hysteresis ratio of each sample was calculated using an Instron tension tester equipped with an integrator unit. In each case, the stretched and heat shrinked sample was fixed between jaws of the Instron tension tester to set the initial length of 10.16 cm (4 inches) regardless of the size of the sample following the heat shrink. Each sample was stretched at 100% elongation under a drawing speed of 500 mm / min. Thus, all samples were stretched to 20.32 cm (8 inches). During stretching, the integrator unit measured the area under the stretching curve and recorded the resulting data. When the elongation reached 100%, the integrator unit was readjusted and relaxation of the Instron Jaws was started until the minimum separation length was 10.16 cm (4 inches). During relaxation, the area under the relaxation curve of the integrator unit was measured. Hysteresis ratio (HR) was calculated as follows.

Since the elastic modulus (for example, rubber) exhibits a hysteresis ratio of about 1.0, the measurement of the hysteresis ratio of the test film provided an index of its elasticity following heat shrinkage. Therefore, single layer films having a heat shrinkage of about 40% to about 60% or more but still having a hysteresis ratio of 2.0 or more are suitable for use as the elastic waist band of disposable diapers. The results are shown in Table 1 below.

TABLE 1

¹ Kraton is a trade name of Shell Oil Co.

² Tuftane is a trade name of Goodrich Chemical.

Example 2

Co-extruded multilayer films with an elastic pyramid core layer and an inelastic film outer layer were obtained using a conventional mixed adapter obtained from Chloeren Co. and of the type described in US Pat. No. 4,152,387. An experiment on permanent strain was performed according to Example 1, and the results are shown in Table 2 below.

TABLE 2a

¹ PE = Chemplex 3404-D was obtained from Chemplex Corp. and Solprene = Solprene 418 was obtained from Phillips Chemical.

² PE = Chemplex Plexar Copolymer.

TABLE 2b

³ PE = Chemplex 3404-D: EVA = Chemplex 3312.

⁴ Plexar 3 is a trade name of Khemflex Corporation.

⁵ EVA = Chemplex 4634.

Example 3

Plexar 102 (obtained from Complex Corporation) and Surlyn-1702 (obtained from Dupont) are 10% / 80% / 10% relative volume compositions (eg outer layer / core layer / outer layer) with core layers of PEBAX2533 and 3533 Example 2 was repeated except using it as an outer layer in. The heat shrinkage rate and hysteresis ratio were tested in the same manner as in Example 1, and the results are shown in Table 3 below.

TABLE 3

Plexar ^* 102 is the ionomer resins, which may be gudeuk from complex captured.

^** Surly 1702 is an ionomer resin that can be gudeuk from the DuPont Company.

From each of the above examples, the disposable diaper, since both the single layer and the coextruded PEBAX film showed satisfactory results in heat shrinkage (eg, about 30-70%) when stretched at an elongation of about 200 to 500%. When applied to the waist band of, for example, it is possible to achieve the formation of suitable wrinkles. For most test films, the heat shrinkage decreased as the film elongation was increased to 300-500%, whereas in the film of the present invention, the heat shrinkage increased as the film elongation was increased to 300-500%. (For example, compare sample numbers 4-5 and 1-2, 8-10 and 11-19). Sample numbers 3 and 6 increase the heat shrinkage slightly, but do not show the necessary heat shrinkage useful for products with elastic wrinkles. Thus, the film of the present invention is economically suitable for producing disposable diapers having elastic waist bands that exhibit the amount of heat shrinkage required to achieve sufficient pleat formation. In addition, since the film of the present invention does not require any thermal curing to obtain the above-mentioned advantages, many commercial and production defects of conventional heat-shrinkable elastomers are overcome.

Claims (20)

(a) uniaxially orienting an elastic body of a first length consisting of a copolymer of alternating polyamide and a polyether repeating polymer segment to a second length longer than the third length at which permanent deformation of the elastic body occurs without external heating treatment And (b) relaxing the uniaxial orientation applied according to step (a) to naturally relax the elastic body to the third length longer than the first length. . The method of claim 1, wherein the elastic body is uniaxially oriented at an elongation of at least 200% to obtain the second length and to produce a heat shrinkage of at least 40%. The method according to claim 1 or 2, wherein the elastic body is uniaxially oriented at an elongation of 200 to 700% to obtain the second length. The method of claim 1, wherein the third length is between 40 and 60% of the second length. The method according to claim 1 or 2, wherein the copolymer has the following general formula.

Wherein R ₁ is a polyamide selected from the group consisting of nylon 6, nylon 10, nylon 11, nylon 12 and nylon 6,6, and R ₂ is from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene glycol Polyether selected and n is an integer. (a) Uniaxially aligning a first length of an elastomer consisting of a copolymer of alternating polyamide and a polyether repeating block polymer segment to a second length longer than the third length where permanent deformation of the elastomer occurs without external heat treatment. Orienting and releasing the uniaxial orientation to naturally relax the elastic body to the third length longer than the first length to provide a heat shrinkage elasticity of at least 20% to form a heat shrinkable elastic body, and (b) process (a And a step of attaching the heat-shrinkable elastic body formed according to the method to the elastic wrinkle part of the product in a direction parallel to the direction in which the wrinkle is to be formed. 7. The method of claim 6, further comprising the step (c) of thermally contracting the attached elastic body to form elastic pleats in the portion of the article such that the elastic body is plastic during thermal contraction. 8. The method of claim 7, wherein step (c) is performed by microwave energy. 8. The method of claim 6 or 7, wherein said third length is between 40 and 60% of said second length. The method of claim 6 or 7, wherein the elastic body is uniaxially oriented at an elongation of 200 to 700% to obtain the second length. 8. The method of claim 6 or 7, wherein the elastic body is uniaxially oriented at an elongation of at least 200% to obtain the second length and at least 40% to produce a heat shrinkage rate. The method according to claim 6 or 7, wherein the copolymer has the following general formula.

Wherein R ₁ is a polyamide selected from the group consisting of nylon 6, nylon 10, nylon 11, nylon 12 and nylon 6,6, and R ₂ is from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene glycol Polyether selected and n is an integer. The method of claim 3, wherein the third length is between 40 and 60% of the second length. The method of claim 13, wherein the copolymer has the general formula:

In the formula, R ₁ is as nylon 6 nylon 10, nylon 11, a polyamide selected from the group consisting of nylon 12 and nylon 6,6, R ₁ is the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene glycol Polyether selected and n is an integer. The method of claim 1, wherein the elastomer comprises an inelastic outer layer and a core layer positioned between the outer layers, the elastomer consisting of the alternating polyamide and polyether repeating block polymer segments. The method according to claim 15, wherein the step of forming the elastic body is carried out by melt laminating the core layer and the outer layer before step (a). The method of claim 16, wherein the core layer is 70 to 90 weight percent of the elastomer. The method of claim 16, wherein the third length is 20 to 60% of the second length. 17. The method of claim 16, wherein said step (a) is performed such that said elastic body is uniaxially oriented at a second length that is between 200 and 700% of said first length. The method of claim 16, wherein the core layer is a copolymer having the general formula:

Wherein R ₁ is a polyamide selected from the group consisting of nylon 6, nylon 10, nylon 11, nylon 12 and nylon 6, 6, and R ₁ is a group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene glycol Polyether selected and n is an integer.

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