JP6030380B2 - Atmospheric pressure dyeable polyethylene terephthalate meltblown nonwoven fabric and method for producing the same - Google Patents

Description

  The present invention relates to a non-woven fabric suitable for batting for clothing, various filters or poultice base fabric materials, and is particularly excellent in form stability, heat resistance and texture, and can be used for purposes and applications by atmospheric dyeing with a cationic dye. The present invention relates to a normal-pressure dyeable polyethylene terephthalate-based meltblown nonwoven fabric that can be a material that enables suitable coloring and a method for producing the same.

  Conventionally, a melted polymer is discharged from an orifice, and is made into fine fibers by high-temperature high-speed gas ejected from the vicinity thereof, and this is collected on a belt conveyor such as a wire mesh to obtain a nonwoven fabric (melt blown method). Is known as a method for directly producing a non-woven fabric made of ultrafine fibers. As a manufacturing feature of the melt blown method, there is a case where a polymer is discharged with a melt viscosity lower by about one order than that in the case of performing ordinary melt spinning. Therefore, it is necessary to use a polymer having a low polymerization degree as compared with ordinary melt spinning or to increase the melting temperature condition of the polymer. Any polymer can be formed into a melt-blown nonwoven fabric as long as the polymer satisfies the above conditions and has a spinnability, that is, a fiber-forming polymer. In fact, melt blown nonwoven fabrics such as various polyolefins, polyamides, polyesters, polyurethanes and the like are manufactured. However, polyethylene terephthalate (hereinafter referred to as PET), which can be said to be a representative of polyester, is hardly produced even though it is generally considered to be a superior polymer in terms of physical properties and cost. Is the current situation. This is especially true when it is a copolymer PET.

  The reason for this is that PET is slower in crystallization speed than crystalline polymers that are frequently used for other meltblown, so when manufactured under ordinary meltblown conditions, the spinnability is good and fine fiberization is no problem at all. Although it is possible, the crystallinity cannot be sufficiently increased at the time of meltblown, so that the thermal stability is low, that is, when it is kept free at a temperature exceeding 70-80 ° C. above the glass transition point. Is a very big problem in practical use because the fiber contracts greatly. In order to improve this point, there has been proposed a method for appropriately increasing the crystallization by appropriately heat-treating the web after melt blown under tension (for example, see Patent Document 1). However, this method requires an additional heat treatment step, and at the same time, the resulting product is likely to generate spherulites, or has a lower strength and texture than a melt blown nonwoven fabric produced from a normal easily crystallized polymer. Only hard, inferior ones can be obtained.

Even in the case of PET, it is possible to obtain a web with an area shrinkage rate of 10% or less at 120 ° C. with fibers crystallized at a low crystallinity if very special conditions such as a very high speed of the jet gas are selected. Yes (see, for example, Patent Documents 2 to 3). In the method described in Patent Document 2, high-pressure (1.5 to 6 kg / cm ² ) air needs to be injected from a narrow air slit of about 0.2 mm. Further, in this method, in the case of PET, crystallization does not proceed unless the intrinsic viscosity η of the polymer after spinning is kept at 0.55 or more, preferably 0.6 or more. For this reason, it is necessary to discharge at a viscosity (500 poise or more) that is considerably higher than the melt viscosity of a polymer that is normally melt-blown. The PET melt blown nonwoven fabric obtained by this method is good in terms of physical properties such as strength, texture and heat resistance. However, when it is manufactured with a wide operating machine with a die width of 1.5 m or more that is actually produced on an industrial scale, it is difficult to adjust the air slit width that is less than 0.3 mm. As a result, it is difficult to operate due to the appearance of wind-like spotted spots on the collection web. Become.

In addition, since the primary air that is ejected is as high as 1.5 kg / cm ² , the primary air cooling effect due to adiabatic expansion is large and easy to cool, and the pseudo-bonding between fibers synergizes with the high melting point of PET. Because of the small size, there is a problem that the fibers in the collection web are easily scattered by the jet air and the collection becomes unstable. This tendency becomes more difficult because the amount of primary air required for thinning increases as the polymer single-hole discharge rate increases. Also, the direction of increasing the discharge rate with high pressure and high viscosity tends to cause shots (polymer balls) and nozzle fouling, making long-term stable production difficult. Therefore, since it must be operated with a low single hole discharge rate (0.1 to 0.2 g / min), the productivity is inferior.

In the method described in Patent Document 3, it is necessary to inject high-pressure secondary air from a narrow slit of 0.2 mm or less, and a long alignment chamber of 1 m or more is also required. Therefore, as with the method described in Patent Document 2, this method also involves a great deal of difficulty in carrying out with an industrial scale wide operating machine.
The above point is the reason why PET meltblown nonwoven fabric is difficult to be practically produced. Despite the high polymer cost, the crystallization speed is high and there is almost no such difficulty. For example, polybutylene terephthalate (hereinafter abbreviated as PBT). Is the representative of polyester meltblown nonwoven fabrics.

A method of melt-blending PET with other polymers at the same time has been proposed (see, for example, Patent Document 4). The method disclosed in Patent Document 4 manufactures a web of ultrafine heat-bonded composite fibers bonded side-by-side by melting PET and PP at different temperatures in separate melt systems and joining them at the spinneret. To do. In this way, the apparatus for joining the two-component polymer flow at the spinneret is relatively easy in normal melt spinning, but it is necessary to arrange a blown air flow path, or a polymer discharge orifice. In the case of a melt blown spinneret that can only be arranged in a single line, the number of holes must be reduced drastically if it is carried out due to the complexity of the equipment, resulting in extremely low productivity. There is a question in terms of practicality. In addition, the fiber obtained by this method does not promote the crystallization of PET and does not contribute to the improvement of the thermal stability as in the case of the conventional melt blown with PET alone.

JP-A-3-045768 JP-A-55-090663 JP-A-1-201564 JP-A-60-099058

  In view of the above problems, the present invention has reached the present invention as a result of intensive studies to obtain a melt-blown nonwoven fabric having good production stability, high productivity, and excellent physical properties of PET using PET. It is a thing. An object of the present invention is to provide a melt-blown nonwoven fabric having a good texture rich in PET strength, thermal form stability and flexibility, and capable of coloring suitable for the purpose and application by atmospheric dyeing with a cationic dye, and a It is intended to provide a production method that can be stably and efficiently produced.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have good productivity, shape stability and heat resistance by blending a small amount of a polyolefin polymer with a copolymerized PET resin in which a specific copolymerization component is copolymerized. , Melt-blown non-woven fabric made of ultra fine fibers with atmospheric pressure dyeable and excellent in texture has a good texture rich in PET strength, thermal form stability and flexibility, and is used for atmospheric pressure dyeing with cationic dyes The present invention has been completed by finding out that coloring suitable for the above can be achieved.

  That is, the present invention comprises a mixed polymer of 75 to 98% by weight of a copolymerized PET resin and 25 to 2% by weight of a polyolefin polymer having a melt index at 230 ° C. of 100 or more, and a dry heat area shrinkage at 120 ° C. of 10% or less. A normal pressure dyeable PET meltblown nonwoven fabric, preferably the above-mentioned normal pressure dyeable polyethylene terephthalate meltblown nonwoven fabric in which the copolymerized PET resin is composed of a dicarboxylic acid component and a glycol component, and more preferably of the dicarboxylic acids 75 mol% or more is a terephthalic acid component, 1.0 mol% to 3.5 mol% is a component derived from a compound represented by the following formula (I), and 2.0 mol% to 10.0 mol % Is a cyclohexane dicarboxylic acid component, and 2.0 mol% to 8.0 mol% is an aliphatic dicarboxylic acid component. It is above atmospheric-pressure dyeable PET-based meltblown nonwoven fabric according to claim Rukoto.

The present invention is preferably a mixed polymer of 75 to 98% by weight of copolymerized PET resin and 25 to 2% by weight of a polyolefin-based polymer having a melt index of 100 or more at 230 ° C., and a jet air pressure of 0.1 kg / cm ² or more, A method for producing a normal pressure dyeable PET meltblown nonwoven fabric, characterized in that meltblown under conditions of 1.0 kg / cm ² or less.

  The melt-blown nonwoven fabric of the present invention has a good texture rich in PET strength, thermal form stability and flexibility, and can be colored suitable for the purpose and application by atmospheric pressure dyeing with a cationic dye.

  In the present invention, a melt blown non-woven fabric composed of a normal pressure dyeable PET ultrafine fiber excellent in productivity, shape stability, heat resistance and texture is obtained by blending a small amount of a polyolefin polymer with a copolymerized PET resin. Hereinafter, the form for implementing this invention is demonstrated concretely.

  The copolymerized PET resin used for the melt blown nonwoven fabric of the present invention is a copolymerized polyester composed of a dicarboxylic acid component and a glycol component. The copolymerized PET resin is a polyester having an ethylene terephthalate unit as a main repeating unit, and among the dicarboxylic acid component, 75 mol% or more of the repeating unit is a terephthalic acid component. It is preferable to consist of the above copolymerization components.

  Further, in the present invention, the copolymerized PET comprises a dicarboxylic acid and a glycol component, and among the dicarboxylic acid component, 75 mol% or more is a terephthalic acid component, and 1.0 mol% to 3.5 mol% is the following. It is a component derived from the compound represented by formula (I), 2.0 mol% to 10.0 mol% is a cyclohexanedicarboxylic acid component, and 2.0 mol% to 8.0 mol% is an aliphatic dicarboxylic acid. It is preferably composed of a polyester fiber that is a component.

Examples of the metal salt (A) of sulfoisophthalic acid represented by the above formula (I) include 5-sodium sulfoisophthalic acid, or sulfonic acid alkali metal bases such as 5-potassium sulfoisophthalic acid and 5-lithium sulfoisophthalic acid. And dicarboxylic acid component having 5-tetraalkylphosphonium sulfoisophthalic acid such as 5-tetrabutylphosphonium sulfoisophthalic acid and 5-ethyltributylphosphonium sulfoisophthalic acid.
Only one type of the metal salt (A) of sulfoisophthalic acid represented by the above formula (I) may be copolymerized in the polyester, or two or more types may be copolymerized.
By copolymerizing the metal salt (A) of sulfoisophthalic acid represented by the above formula (I), the amorphous structure can be retained in the fiber internal structure as compared with the conventional polyester fiber, and as a result, the dispersion Normal pressure dyeing is possible for dyes and cationic dyes.

  When the copolymerization amount of the metal salt (A) of sulfoisophthalic acid represented by the above formula (I) is less than 1.0 mol%, a cationic dyeable dye which becomes clear and has a good color tone when dyed with a cationic dye. Can not be obtained. On the other hand, when the copolymerization amount of (A) exceeds 3.5 mol%, the viscosity of the polyester is remarkably increased and spinning becomes difficult. The amount becomes excessive and the clarity of the color tone is rather lost. From the viewpoint of the sharpness and spinnability of the dyed product, the copolymerization amount of (A) is preferably 1.2 to 3.0 mol%, more preferably 1.5 to 2.5 mol%. preferable.

  In the present invention, among dicarboxylic acid components, cyclohexanedicarboxylic acid and / or an ester-forming derivative thereof is 2.0 to 10.0 mol%, preferably 5.0 to 10.0 mol%, and aliphatic dicarboxylic acid. And / or its ester-forming derivative is preferably copolymerized in an amount of 2.0 to 8.0 mol%, preferably 3.0 to 6.0 mol%.

  When cyclohexanedicarboxylic acid or its ester-forming derivative (hereinafter also referred to as cyclohexanedicarboxylic acid component) is copolymerized with PET, it has a characteristic that the disorder of the crystal structure is small, so a high dyeing rate is secured. Meanwhile, a fiber excellent in light fastness can be obtained.

  By copolymerizing the cyclohexanedicarboxylic acid component, the crystal structure of the polyester fiber is disturbed, and the orientation of the amorphous part is lowered. Therefore, it is suitable for producing a nonwoven fabric by melt blown, and the penetration of the cationic dye and the disperse dye into the fiber is facilitated, and the atmospheric pressure dyeability of the cationic dye and the disperse dye can be improved. . Furthermore, since the cyclohexane dicarboxylic acid component is less disturbed in crystal structure than other aliphatic dicarboxylic acids, it is excellent in light fastness.

  If the amount of copolymerization of the cyclohexanedicarboxylic acid component is less than 2.0 mol% in the dicarboxylic acid component, the degree of orientation of the amorphous part inside the fiber will be high, so that the dyeability in a normal pressure environment will be insufficient and the target dyeing will be insufficient. It is not preferable because the dressing rate cannot be obtained. Moreover, when it exceeds 10.0 mol% in the dicarboxylic acid component, a stable meltblown nonwoven fabric cannot be obtained due to the low glass transition temperature of the resin and the low degree of orientation of the amorphous part inside the fiber.

  The cyclohexanedicarboxylic acid used in the present invention includes three positional isomers of 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. From the point obtained, any positional isomer may be copolymerized, or a plurality of positional isomers may be copolymerized. Further, although there are cis / trans isomers for each positional isomer, any stereoisomer may be copolymerized, or both cis / trans positional isomers may be copolymerized. The same applies to the cyclohexanedicarboxylic acid derivative.

  As for the fatty acid dicarboxylic acid and its ester-forming derivative component, similarly to the cyclohexyne dicarboxylic acid component, the crystal structure of the polyester fiber is disturbed and the orientation of the amorphous part is lowered. In addition to being suitable, the penetration of the cationic dye and the disperse dye into the fiber is facilitated, and the atmospheric dyeability can be improved.

  If the copolymerization amount of the fatty acid component in the dicarboxylic acid component is less than 2.0 mol%, the degree of orientation of the amorphous part inside the fiber is high, so that the dyeing property for the disperse dye under the normal pressure environment is insufficient. This is not preferable because a dyeing rate of 2 is not obtained. Moreover, when the copolymerization amount of the fatty acid component in the dicarboxylic acid component exceeds 8.0 mol%, the degree of orientation of the amorphous part in the fiber is lowered, and a stable meltblown nonwoven fabric cannot be obtained, which is not preferable.

  Preferred examples of the aliphatic dicarboxylic acid component of the present invention include aliphatic dicarboxylic acids such as adipic acid, sebacic acid and decanedicarboxylic acid. These can be used alone or in combination of two or more.

  As long as the atmospheric pressure dyeability and quality of the melt blown nonwoven fabric in the present invention are not deteriorated, other dicarboxylic acid components other than the terephthalic acid component, cyclohexane dicarboxylic acid component, and aliphatic dicarboxylic acid component may be copolymerized. Also good. Specifically, an aromatic dicarboxylic acid component such as isophthalic acid or naphthalenedicarboxylic acid or an ester-forming derivative thereof may be used alone or a plurality of types may be copolymerized within a range of 10.0 mol% or less.

  However, copolymerization of these components not only makes the transesterification reaction and polycondensation reaction complicated, but if the amount of copolymerization exceeds an appropriate range, washing fastness may be reduced. Specifically, when isophthalic acid and its ester-forming derivative are copolymerized in an amount exceeding 10 mol% with respect to the dicarboxylic acid component, the fastness to washing may be deteriorated even if the constituent requirements of the present invention are satisfied. It is desirable that the amount be 5 mol% or less, more desirably 0 mol% (not copolymerize).

  Furthermore, the copolymerized PET resin of the present invention includes a matting agent such as titanium oxide, barium sulfate and zinc sulfide, a heat stabilizer such as phosphoric acid and phosphorous acid, a light stabilizer, an antioxidant, an oxidation agent, respectively. A surface treatment agent such as silicon may be included as an additive. By using silicon oxide, the resulting fiber can impart fine irregularities to the fiber surface after weight reduction processing, and darkening is realized when it is later made into a woven or knitted fabric. Furthermore, thermal decomposition during heat melting or subsequent heat treatment can be suppressed by using a heat stabilizer. Moreover, the light resistance at the time of use of a fiber can be improved by using a light stabilizer, and it is also possible to improve dyeability by using a surface treating agent.

  These additives may be added in advance to the polymerization system when the copolymerized PET resin is obtained by polymerization. However, it is generally preferable to add an antioxidant or the like at the end of the polymerization, and this is preferable particularly when the polymerization system is adversely affected or when the additive is deactivated under the polymerization conditions. On the other hand, matting agents, heat stabilizers, and the like are preferably added at the time of polymerization because they are easily dispersed uniformly in the resin polymer.

  The copolymerized PET resin of the present invention has an intrinsic viscosity of 0.55 to 0.7, preferably 0.58 to 0.68, and more preferably 0.58 to 0.60. When the intrinsic viscosity exceeds 0.7, the high-speed spinnability at the time of fiberization becomes extremely poor. On the other hand, when the intrinsic viscosity is less than 0.55, the PP mixing ratio increases, and it becomes difficult to suppress the dry heat area shrinkage ratio at 120 ° C. to 10% or less.

  The general-purpose PET resin cannot reduce the thermal shrinkage of the obtained melt blown nonwoven fabric unless it is melt blown with air having a high viscosity and a high pressure as compared with the melt blown conditions of other easily crystalline polymers such as polypropylene. Further, as described above, productivity and operational stability are lacking under such conditions. The present inventors have studied to solve these problems by using relatively low pressure air. That is, by blending an appropriate amount of polyolefin, which is a polymer that is incompatible with atmospheric pressure dyeable copolymer PET, has a high crystallization rate, and has a sufficiently low melt viscosity, the melt viscosity of the entire blend system is reduced. By exhibiting the “viscous effect”, it becomes easy to make the normal pressure dyeable copolymer PET fine fiber, and a predetermined melt blown nonwoven fabric can be obtained. If the polymer blended with atmospheric pressure dyeable copolymer PET has similar chemical structure such as polybutylene terephthalate, which is the same polyester polymer, it will achieve the purpose of inhibiting each other's crystallization ability. Can not do it. However, as a result of the study by the present inventors, blending 2 to 25% of a polyolefin-based polymer was most effective in achieving the above object. That is, as the polyolefin-based polymer used in the present invention, polyethylene (particularly LL-PE), polypropylene (PP), polymethylpentene (PMP) and the like are effective, and polypropylene or polymethylpentene has a low melt viscosity. This is preferable in that it has a good spinnability. In order to sufficiently obtain the “thinning effect” of the polymer to be blended, it is preferable to use a low melt viscosity grade. For example, in the case of PP, the melt index at 230 ° C. is 100 or more. preferable.

By blending 2-25% of the specified polyolefin polymer with normal pressure dyeable copolymerized PET, the melt viscosity of the entire system is lowered, so the polymer can be used even with a relatively weak force of low pressure air of 1.0 kg / cm ² or less. The stream can be made finer. The reason why a non-woven fabric with good thermal form stability is obtained in the present invention is that it is a sea-island mixed form in which polyolefin is dispersed as fine island components in the continuous sea phase of atmospheric pressure dyeable copolymerized PET, In order to crystallize appropriately, even if each amorphous molecule moves and contracts due to heating, this crystal part serves as a restraint point for suppressing molecular movement, so that it is possible to obtain a melt-blown nonwoven fabric with reduced thermal shrinkage. Presumed to be possible. When a differential thermal analysis of these meltblown nonwoven fabric fibers is performed, crystal melting peaks of both atmospheric pressure dyeable copolymerized PET and olefinic polymer are observed. However, if the blend ratio of the polyolefin polymer is too small, the melt viscosity of the entire system will not be sufficiently lowered, and it will be difficult to make a fine fiber with the weak force of low-pressure air. Although orientation crystallization is difficult to proceed and heat shrinkage is small, when heat treatment is performed at a temperature higher than the glass transition point by thermal calendering or the like, sticking occurs between the fibers, and the nonwoven fabric has a paper-like rough texture. Increasing the amount of air causes scattering of fibers in the web, making stable collection difficult. From these points, the lower limit of the blend ratio of the polyolefin polymer is 2%. On the other hand, when the mixing ratio of the polyolefin polymer is increased, it becomes difficult to uniformly finely disperse the polyolefin polymer in the normal pressure dyeable copolymerized PET. The yarn property is lowered, the thinning is poor, the yarn is broken, and it is difficult to stably obtain a melt blown nonwoven fabric. In this respect, the blend ratio of the polyolefin-based polymer must be 25% by weight or less, preferably 20% by weight or less.

  If the mixed state of the normal pressure dyeable copolymer PET and the polyolefin polymer is non-uniform and the polyolefin polymer is present in a large lump in the polyester, shots due to poor thinning are likely to occur, and a stable meltblown cannot be performed. It is necessary to disperse the polyolefin-based polymer almost uniformly in the pressure-dyeable copolymerized PET. The mixing method may be any method as long as the polyolefin polymer is finely dispersed almost uniformly in the atmospheric pressure dyeable copolymerized PET. From the point of uniformity, it is preferable to mix and knead in a pellet form before melting, or to knead the kneaded material or to use it after further pelletizing. In such a method, no special apparatus is required, and a conventional single-component meltblown apparatus can be used as it is, which is advantageous in terms of apparatus.

The spinning head for carrying out the method of the present invention does not require any special improvement such as narrowing the slit for blowing air, and can be performed using a conventional one that has been conventionally used. . According to the method of the present invention, since the melt viscosity of the mixed polymer is sufficiently lowered, the single hole discharge rate is 0.2 g / min or more and 1.0 g / min by blowing with low pressure air of 1.0 kg / cm ² or less. Melt blown can be stably performed in the following high discharge amount range. Even if the discharge amount is reduced to some extent, spinning can be performed stably, but the production efficiency is lowered. On the other hand, if the discharge rate of the single hole is larger than 1.0 g / min, it is difficult to make fine fibers with low-pressure air, and it is necessary to increase the amount of air in order to sufficiently make fine fibers. In this case, if the amount of air is excessively large, the above-described problems occur, and production tends to become unstable. Further, the air pressure is preferably 0.1 kg / cm ² or more, and if it is lower than this, fine fiber formation does not proceed sufficiently.

  The temperature at which the polymer is melted and the temperature of the spinneret are preferably low in a range that satisfies the purpose from the viewpoint of deterioration of the polymer and the like, and the temperature range in which the melt viscosity of the entire system in the spinneret is 200 to 500 poise. Is selected.

  The average fiber diameter of the melt blown web obtained in this way varies depending on the single hole discharge amount, air pressure, spinneret temperature, etc., but is usually 10 μm or less, and a crystallized ultrafine fiber web having an average fiber diameter of 1 to 3 ηm. Can be manufactured stably. Since this melt blown web has PET fibers crystallized appropriately, it hardly shrinks even when heated, and the dry heat shrinkage (area shrinkage) when heated for 2 minutes in hot air at 120 ° C. is usually 10%. It is as follows.

  Next, in order to describe the present invention more specifically, examples of the present invention will be shown below, but the present invention is not limited to these examples. In the examples, “parts” or “%” refers to weight unless otherwise specified.

[Examples 1-5, Comparative Examples 1-2]
Of the dicarboxylic acid component, 88.3 mol% is terephthalic acid, 1.7 mol% of 5-sodium sulfoisophthalic acid, 5.0 mol% of 1,4-cyclohexanedicarboxylic acid, and 5.0 of adipic acid. A transesterification reaction and a polycondensation reaction were performed with the total carboxylic acid component, ethylene glycol, and predetermined additives contained in each mol%, to obtain a copolymerized PET resin polymer having an intrinsic viscosity of 0.62.
Polypropylene polymer having a melt index of 200 with the copolymerized PET polymer blended in the form of pellets at the mixing ratio shown in Table 1 is heated and melted with an extruder, and then 0.3 mmΦ orifices are aligned in a row with 1 hole pitch of 2001 holes. The melt blown nozzles were discharged from the arranged melt blown nozzles with a die width of 2000 mm, heated air was sprayed from an air slit with a slit width of 1 mm, and the thinned fibers were collected on a wire mesh belt conveyor running below the melt blown web. . Melt blown conditions at this time, dry heat area shrinkage rate at 120 ° C. of melt blown web, strong elongation after bonding the web with an embossed calendar at 15% pressure bonding area and 180 ° C., and area shrinkage rate after dyeing at 120 ° C. Is shown in Table 1.

The melt-blown nonwoven fabric of the present invention has a good texture rich in PET strength, thermal form stability and flexibility, and can be colored suitable for the purpose and application by atmospheric pressure dyeing with a cationic dye. It can be developed for the uses 1) to 3).

1) Medical materials, poultice base fabric, surgical tape, bed sheets, medical drapes 2) Industrial materials Automotive interior materials (ceiling materials, door trim materials, sound absorbing materials), wallpaper, shoji paper, paper sheets, compost sheets, work clothes, house wraps , Air filters, liquid filters 3) Others Deodorizing mats for pets, clothes covers, food packaging materials

Claims (2)

Copolymer polyethylene terephthalate resin 75 to 98% by weight and a mixed polymer of polyolefin polymer 25 to 2% by weight having a melt index at 230 ° C. of 100 or more. The copolymer polyethylene terephthalate resin is composed of a dicarboxylic acid component and a glycol component. In the dicarboxylic acid component, 75 mol% or more is a terephthalic acid component, and 1.0 mol% to 3.5 mol% is a component derived from a compound represented by the following formula (I). Dry heat area shrinkage at 120 ° C. , characterized in that 0 mol% to 10.0 mol% is a cyclohexane dicarboxylic acid component and 2.0 mol% to 8.0 mol% is an aliphatic dicarboxylic acid component Normal pressure dyeable polyethylene terephthalate-based meltblown nonwoven fabric having a 10% or less.

[In the above formula, R represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or an ester-forming functional group, and X represents an alkali metal salt. ] A mixed polymer of 75 to 98% by weight of a copolymer polyethylene terephthalate resin and 25 to 2% by weight of a polyolefin-based polymer having a melt index of 100 or more at 230 ° C. is applied to a jet air pressure of 0.1 kg / cm ² or more and 1.0 kg / cm. method for producing a normal-pressure dyeing polyethylene terephthalate-based meltblown nonwoven fabric according to claim 1, characterized in that the meltblown ² following conditions.