阅读说明：本技术 熔喷无纺布 (Melt-blown nonwoven fabric ) 是由 周上智 张绍彦 林俊宏 廖元培 赖奕苍 于 2020-01-13 设计创作，主要内容包括：本发明提供一种熔喷无纺布,包括彼此黏附的多条熔喷纤维。多条熔喷纤维中的每一者的材质包括聚醚酰亚胺及聚酰亚胺或者聚苯硫醚及聚酰亚胺,其中所述聚酰亚胺的玻璃转移温度介于128℃至169℃之间,所述聚酰亚胺的10％热重损失温度介于490℃至534℃之间,以及当所述聚酰亚胺溶于N-甲基-2-吡咯啶酮且固含量为30wt％时,黏度介于100cP至250cP之间。所述熔喷无纺布具有良好耐热性、良好阻燃性、良好尺寸稳定性、良好介电性质、低熔喷温度且燃烧后不会产生融滴现象。(The invention provides a melt-blown nonwoven fabric, which comprises a plurality of melt-blown fibers adhered to each other. The material of each of the plurality of melt-blown fibers comprises polyetherimide and polyimide or polyphenylene sulfide and polyimide, wherein the glass transition temperature of the polyimide is between 128 ℃ and 169 ℃, the 10% thermogravimetric loss temperature of the polyimide is between 490 ℃ and 534 ℃, and the viscosity of the polyimide is between 100cP and 250cP when the polyimide is dissolved in N-methyl-2-pyrrolidone and the solid content is 30 wt%. The melt-blown non-woven fabric has the advantages of good heat resistance, good flame retardance, good dimensional stability, good dielectric property, low melt-blowing temperature and no melt-drip phenomenon after combustion.)

1. A melt-blown nonwoven fabric, comprising:

a plurality of meltblown fibers adhered to one another, wherein each of the plurality of meltblown fibers comprises:

a polyetherimide; and

a polyimide, wherein the polyimide has a glass transition temperature between 128 ℃ and 169 ℃, a 10% thermal weight loss temperature between 490 ℃ and 534 ℃, and a viscosity between 100cP and 250cP when the polyimide is dissolved in N-methyl-2-pyrrolidone with a solid content of 30 wt%.

2. The melt-blown nonwoven fabric according to claim 1, wherein the content of the polyimide is 1 to 10 parts by weight based on 100 parts by weight of the polyetherimide.

3. The meltblown nonwoven fabric according to claim 1, wherein each of the plurality of meltblown fibers has a diameter between 1 μ ι η and 10 μ ι η.

4. The meltblown nonwoven according to claim 1, wherein the dielectric constant of the meltblown nonwoven is between 1.8 and 2.5 at a frequency of 10 GHz.

5. The meltblown nonwoven according to claim 1, wherein the dielectric loss of the meltblown nonwoven is between 0.0025 and 0.0050 at a frequency of 10 GHz.

6. The meltblown nonwoven according to claim 1, wherein the limiting oxygen index of the meltblown nonwoven is between 30 and 35.

7. The meltblown nonwoven according to claim 1, wherein the meltblown nonwoven has a meltblowing temperature between 300 ℃ and 350 ℃.

8. A melt-blown nonwoven fabric, comprising:

a plurality of meltblown fibers adhered to one another, wherein each of the plurality of meltblown fibers comprises:

polyphenylene sulfide; and

a polyimide, wherein the polyimide has a glass transition temperature between 128 ℃ and 169 ℃, a 10% thermal weight loss temperature between 490 ℃ and 534 ℃, and a viscosity between 100cP and 250cP when the polyimide is dissolved in N-methyl-2-pyrrolidone with a solid content of 30 wt%.

9. The meltblown nonwoven fabric according to claim 8, wherein the polyimide is present in an amount of 1 to 10 parts by weight, based on 100 parts by weight of the polyphenylene sulfide.

10. The meltblown nonwoven fabric of claim 8, wherein each of the plurality of meltblown fibers has a diameter between 1 μ ι η and 10 μ ι η.

11. The meltblown nonwoven according to claim 8, wherein the meltblown nonwoven has a dielectric constant between 2.6 and 2.9 and a dielectric loss between 0.0030 and 0.0050 at a frequency of 10 GHz.

12. The melt-blown nonwoven fabric according to claim 8, wherein the heat shrinkage ratio of the melt-blown nonwoven fabric after being left to stand at a temperature of 140 ℃ for 24 hours is 5% or less, and the heat shrinkage ratio of the melt-blown nonwoven fabric after being left to stand at a temperature of 180 ℃ for 24 hours is 10% or less.

13. The meltblown nonwoven according to claim 8, wherein the limiting oxygen index of the meltblown nonwoven is between 29 and 31.

14. The meltblown nonwoven according to claim 8, wherein the meltblown nonwoven has a meltblowing temperature between 290 ℃ and 310 ℃.

Technical Field

The invention relates to a non-woven fabric, in particular to a melt-blown non-woven fabric.

Background

Non-woven fabrics are a product of textile fabrics, which are not made by traditional weaving methods such as weaving or knitting. With the progress of the textile industry, nonwoven fabrics prepared by melt-blowing processes have been developed, which can be applied to diapers, wiping cloths, medical care materials, sports apparel, down jackets, and the like. Currently, thermoplastic resins called "engineering plastics" having excellent properties such as heat resistance, chemical resistance, and flame retardancy are used as materials for nonwoven fabrics produced by a melt-blowing process. However, the use of engineering plastics is still limited. For example, the processing temperatures of polyetherimides are relatively high (between 350 ℃ and 380 ℃), which is not easily achievable with typical equipment. Further, when polyvinylidene fluoride is molded at a high temperature, hydrofluoric acid having strong corrosiveness is easily generated when the processing temperature is 320 ℃. Therefore, how to improve the applicability of engineering plastics is still an important issue of active research.

Disclosure of Invention

The invention provides a melt-blown nonwoven fabric which has good heat resistance, good flame retardance, good dimensional stability, good dielectric properties, low melt-blowing temperature and no melt-drip phenomenon after combustion.

The invention also provides a melt-blown non-woven fabric which has good heat resistance, good flame retardance, good chemical resistance, good heat shrinkage resistance, good dielectric properties, low process temperature and no melt-drip phenomenon after combustion.

The meltblown nonwoven fabric of the present invention includes a plurality of meltblown fibers adhered to one another. The material of each of the plurality of melt-blown fibers comprises polyetherimide and polyimide, wherein the glass transition temperature of the polyimide is between 128 ℃ and 169 ℃, the 10% thermal weight loss temperature of the polyimide is between 490 ℃ and 534 ℃, and the viscosity of the polyimide is between 100cP and 250cP when the polyimide is dissolved in N-methyl-2-pyrrolidone (NMP) and the solid content is 30 wt%.

Another meltblown nonwoven of the present invention includes a plurality of meltblown fibers adhered to one another. The material of each of the plurality of melt-blown fibers comprises polyphenylene sulfide and polyimide, wherein the glass transition temperature of the polyimide is between 128 ℃ and 169 ℃, the 10% thermal weight loss temperature of the polyimide is between 490 ℃ and 534 ℃, and the viscosity of the polyimide is between 100cP and 250cP when the polyimide is dissolved in N-methyl-2-pyrrolidone (NMP) and the solid content is 30 wt%.

Based on the above, the melt-blown non-woven fabric of the invention comprises a plurality of melt-blown fibers made of polyetherimide and polyimide with a glass transition temperature of 128 ℃ to 169 ℃, a 10% thermogravimetric loss temperature of 490 ℃ to 534 ℃, a viscosity of 100cP to 250cP when being dissolved in NMP and having a solid content of 30 wt%, or polyphenylene sulfide and polyimide with a glass transition temperature of 128 ℃ to 169 ℃, a 10% thermogravimetric loss temperature of 490 ℃ to 534 ℃, and a viscosity of 100cP to 250cP when being dissolved in NMP and having a solid content of 30 wt%, so that the melt-blown non-woven fabric has good heat resistance, good flame retardancy, good dielectric properties, a low melt-blowing temperature, and no melt-drip phenomenon after combustion.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Detailed Description

In this context, a range denoted by "a numerical value to another numerical value" is a general expression avoiding a recitation of all numerical values in the range in the specification. Thus, recitation of a range of values herein is intended to encompass any value within the range and any smaller range defined by any value within the range, as if the range and smaller range were explicitly recited in the specification.

Herein, the structure of a polymer or group is sometimes represented by a bond line type (skeletton formula). This notation may omit carbon atoms, hydrogen atoms, and carbon-hydrogen bonds. Of course, atoms or groups of atoms are explicitly depicted in the structural formulae, and so on.

As used herein, "about", "approximately", "essentially", or "substantially" includes the stated value and the average value within an acceptable range of deviation of the specified value as determined by one of ordinary skill in the art, taking into account the measurement in question and the specified amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within, for example, ± 30%, ± 20%, ± 15%, ± 10%, ± 5%. Further, as used herein, "about," "approximately," "essentially," or "substantially" may be selected based on the measured property or other property to select a more acceptable range of deviation or standard deviation, and not all properties may be accommodated with one standard deviation.

In order to provide a melt-blown nonwoven fabric which has good heat resistance, good flame retardancy, good dimensional stability, good dielectric properties, a low melt-blowing temperature and does not generate melt-drip phenomenon after combustion, the invention provides a melt-blown nonwoven fabric which can achieve the advantages. The following embodiments are merely examples of the present invention which can be actually carried out.

One embodiment of the present invention provides a meltblown nonwoven fabric including a plurality of meltblown fibers adhered to one another. In particular, the plurality of meltblown fibers are randomly interlaced with respect to each other. In this embodiment, the basis weight of the meltblown nonwoven is between about 1g/m²To 100g/m²In the meantime.

In this embodiment, the material of each of the plurality of meltblown fibers includes polyetherimide and polyimide. That is, the material of the meltblown nonwoven fabric is a master batch (i.e., a composition) including polyetherimide and polyimide. More specifically, in the present embodiment, the method for producing a master batch (i.e., a composition) containing a polyetherimide and a polyimide includes subjecting the polyetherimide and the polyimide to a hot-melt process to mix the polyetherimide and the polyimide. The hot melting process utilizes heating and/or applying pressure to melt and bond together multiple materials (e.g., polyetherimide and polyimide). In this embodiment, the hot-melting process may include (but is not limited to): a melt-kneading granulation process, a hot-pressing process, a hot-air bonding process, or a melt-spinning process. In the present embodiment, the process temperature of the hot melting process may be between about 300 ℃ to about 350 ℃.

In the present embodiment, the meltblown nonwoven fabric can be produced by: a composition comprising a polyetherimide and a polyimide is melted at a high temperature, and the molten composition is ejected in a fibrous form from a spinning nozzle, and the ejected fibrous molten composition is pulled by a high-temperature high-speed gas, thereby obtaining a plurality of melt-blown fibers on a collecting device. In the present embodiment, the meltblown nonwoven fabric can be obtained by directly collecting a plurality of meltblown fibers. However, the invention is not limited thereto, and in other embodiments, the collected meltblown fibers may be processed by a hot pressing process to obtain a meltblown fiber nonwoven film (or meltblown fiber film).

In each meltblown fiber of the present embodiment, the polyimide may be present in an amount of about 1 to about 10 parts by weight, based on 100 parts by weight of the polyetherimide. In other words, in a composition including a polyetherimide and a polyimide, the polyimide may be used in an amount of about 1 part by weight to about 10 parts by weight, based on 100 parts by weight of the polyetherimide. If the amount of polyimide used is less than 1 part by weight, the melt-blown fiber cannot be produced by significantly improving the hot workability of the polyetherimide; on the other hand, if the amount of the polyimide is more than 10 parts by weight, the composition is poor in continuous processability, and it is difficult to produce a uniform melt-blown fiber nonwoven fabric or a film thereof.

Polyetherimide is a thermoplastic amorphous polymer and has the property of being solvent soluble. In this embodiment, the polyetherimide can comprise repeating units represented by formula I below:formula I. That is, the polyetherimide can be prepared from bisphenol A type diether dianhydride (4,4 '- (4, 4' -iso)prepared by reacting propylidenephenol bis (phthalic anhydride) (BPADA for short) with m-phenylenediamine (m-phenylene diamine for short) and the like. In this embodiment, the polyetherimide may be a commercially available product such as: spin grade ULTEM 9011PEI and ULTEM 1010PEI manufactured by Sabic basic industries, inc (Sabic). In this embodiment, the polyetherimide can have a weight average molecular weight of between about 44000g/mol to about 50000 g/mol. In addition, polyetherimide has good heat resistance, flame resistance and dyeability, so that melt blown fibers made of materials including polyetherimide and polyimide have good heat resistance, flame resistance and dyeability.

In this embodiment, the glass transition temperature of the polyimide is between about 128 ℃ and about 169 ℃, the 10% thermal weight loss temperature of the polyimide is between about 490 ℃ and about 534 ℃, and the viscosity is between about 100cP and about 250cP when the polyimide is dissolved in N-methyl-2-pyrrolidone (NMP) and has a solid content of about 30 wt%. If the glass transition temperature, 10% thermogravimetric loss temperature and viscosity of the polyimide do not fall within the above ranges, the thermoplastic composition obtained in the subsequent step is poor in thermal processability and thermal stability.

In addition, in the present embodiment, the polyimide may include a repeating unit represented by formula 1:

wherein Ar is a tetravalent organic group derived from a tetracarboxylic dianhydride compound containing an aromatic group, and A is a divalent organic group derived from a diamine compound containing an aromatic group. That is, Ar is a tetracarboxylic dianhydride compound containing an aromatic group except 2 carboxylic anhydride groups (- (CO)₂A residue other than O); and A is a diamine compound containing an aromatic group except 2 amino groups (-NH)₂) Other residues. In the present embodiment, at least one of the tetravalent organic group and the divalent organic group contains an ether group. That is, the composition containsAt least one of the tetracarboxylic dianhydride compound having an aromatic group and the diamine compound having an aromatic group contains an ether group. Herein, the tetracarboxylic dianhydride compound containing an aromatic group is also referred to as a dianhydride monomer, and the diamine compound containing an aromatic group is also referred to as a diamine monomer. In the present embodiment, the polyimide can be obtained by reacting a dianhydride monomer with a diamine monomer.

In this embodiment, Ar may be Specifically, the dianhydride monomer used for preparing the polyimide may be bisphenol a diether dianhydride (4,4 '- (4, 4' -isopropylidenediphenyl) bis (phthalic anhydride), BPADA for short), diphenylether tetracarboxylic dianhydride (oxydiphthalic anhydride), ODPA for short), pyromellitic dianhydride (PMDA for short), 3 ', 4, 4' -benzophenone tetracarboxylic dianhydride (3,3 ', 4, 4' -benzophenone tetracarboxylic dianhydride, BTDA for short), or 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride (3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride, BPDA for short).

In this embodiment, A may be Specifically, the diamine monomer for preparing polyimide can be meta-phenylene diamine (m-PDA), 2-bis [ (4-aminophenoxy) phenyl group]Propane (BAPP for short), 4 ' -diaminodiphenyl sulfone (4,4 ' -diaminodiphenyl sulfone), 4 ' -diaminodiphenyl ether (4,4 ' -oxydianiline/4,4 ' -diaminodiphenyl ether for short, ODA), 3 ' -diaminobenzophenone (3,3 ' -diaminodiphenyl ketone for short)e) 1,3-bis (4-aminophenoxy) benzene (1,3-bis (4-aminophenoxy) benzene, TPE-R for short), 3,4 ' -diaminodiphenyl ether (3,4 ' -oxydianiline/3,4 ' -diaminodiphenyl ether) or 3,5-diaminobenzoic acid (3,5-diaminobenzoic acid, DABA for short).

Specifically, in the present embodiment, the polyimide can be produced by, for example, a condensation polymerization method and a thermal cyclization method or a condensation polymerization method and a chemical cyclization method. The condensation polymerization method, the thermal cyclization method, and the chemical cyclization method can each be carried out by any step known to those skilled in the art. In one embodiment, the preparation of the polyimide by the condensation polymerization method and the chemical cyclization method may include the steps of: after a dianhydride monomer and a diamine monomer are subjected to a condensation polymerization reaction in a solvent to form a polyamic acid solution, a dehydrating agent and an imidizing agent are added to the polyamic acid solution to perform an imidization reaction (i.e., a dehydrative cyclization reaction) to form a polyimide. In another embodiment, the preparation of the polyimide by the condensation polymerization method and the thermal cyclization method may include the steps of: after a dianhydride monomer and a diamine monomer are subjected to a condensation polymerization reaction in a solvent to form a polyamic acid solution, the polyamic acid solution is heated to perform an imidization reaction (i.e., a dehydrative cyclization reaction) to form a polyimide.

The solvent is not particularly limited as long as it can dissolve the dianhydride monomer and the diamine monomer. Specifically, examples of the solvent include (but are not limited to): amide solvents such as N, N-dimethylacetamide (DMAc), N-Dimethylformamide (DMF), N' -diethylacetamide, NMP, γ -butyrolactone, and hexamethylphosphoric triamide; urea solvents such as tetramethylurea and N, N-dimethylethylurea; sulfoxide or sulfone solvents such as dimethyl sulfoxide, diphenyl sulfone and tetramethyl sulfone; halogenated alkyl solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene; phenol solvents such as phenol and cresol; or ether solvents such as tetrahydrofuran, 1, 3-dioxolane, dimethyl ether, diethyl ether, and p-cresol methyl ether. The above solvents may be used alone or in combination of plural kinds. In order to improve the solubility and reactivity of the dianhydride monomer and the diamine monomer, the solvent is preferably an amide solvent such as DMAc, DMF, NMP, or the like. Additionally, examples of the dehydrating agents include (but are not limited to): acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride or trifluoroacetic anhydride; examples of such imidizing agents include, but are not limited to: pyridine, picoline, quinoline or isoquinoline.

In the present embodiment, the number of kinds of diamine monomers and the number of kinds of dianhydride monomers used to prepare the polyimide are not limited as long as the polyimide has a glass transition temperature of between about 128 ℃ and about 169 ℃, a 10% thermal weight loss temperature of between about 490 ℃ and about 527 ℃, and a viscosity of between 171cP and 250cP in the case where the solvent is NMP and the solid content is 30 wt%, and has appropriate hot melt processability and solvent solubility characteristics. For example, polyimides can be obtained by reacting a diamine monomer with a dianhydride monomer. For example, the polyimide may be obtained by reacting a plurality of diamine monomers with one dianhydride monomer, one diamine monomer with a plurality of dianhydride monomers, or a plurality of diamine monomers with a plurality of dianhydride monomers.

In the melt-blowing process of the present embodiment, the melt-blowing temperature of the melt-blown nonwoven fabric may be between about 300 ℃ and about 350 ℃. Generally, in the manufacture of unmodified polyetherimide meltblown nonwoven fabrics, the meltblowing temperature is between about 380 ℃ to about 400 ℃. In view of this, the meltblown nonwoven fabric of the present embodiment can be manufactured at a reduced meltblowing temperature.

In the melt-blowing process of the present embodiment, the high-temperature and high-velocity gas has a temperature of about 400 ℃ to about 450 ℃ and a draft pressure of about 3kg/cm²To about 7kg/cm²In the meantime. In addition, the high-temperature and high-velocity gas may be air or nitrogen.

In this embodiment, each meltblown fiber has a diameter between about 1 μm and about 10 μm. That is, the meltblown nonwoven fabric of the present embodiment may be composed of very fine microfibers.

In this embodiment, the melt blown nonwoven fabric has a dielectric constant between about 1.8 and about 2.5 and a dielectric loss between about 0.0025 and about 0.0050 at a frequency of 10 GHz. That is, the meltblown nonwoven fabric of the present embodiment has good dielectric properties. Thus, the meltblown nonwoven fabric of the present embodiment is suitable for use as a substrate in a flexible printed circuit board. On the other hand, as mentioned above, the dielectric loss of the meltblown is between about 0.0025 and about 0.0050 at 10GHz, so the meltblown can meet the specification requirement of the fifth generation mobile communication system (5G).

In this embodiment, the Limiting Oxygen Index (LOI) of the meltblown nonwoven is between about 30 and about 35. That is, the meltblown nonwoven fabric of the present embodiment has good flame retardancy.

It should be noted that, in the present embodiment, the meltblown nonwoven fabric includes a plurality of meltblown fibers made of polyetherimide and polyimide, and the glass transition temperature of the polyimide is between 128 ℃ and 169 ℃, the 10% thermogravimetric loss temperature of the polyimide is between 490 ℃ and 534 ℃, and the viscosity of the polyimide is between 100cP and 250cP when the polyimide is dissolved in NMP and the solid content is 30 wt%, so that the meltblown nonwoven fabric has good heat resistance, good flame retardancy, good dimensional stability, good dielectric properties, low meltblowing temperature, and no meltdrop phenomenon after combustion.

In addition, in each of the meltblown fibers of the present embodiment, the content of polyimide is about 1 to about 10 parts by weight based on 100 parts by weight of the polyetherimide, so that the polyetherimide can be regarded as a main component and the polyimide can be regarded as a plasticizer for imparting good thermal processability to the polyetherimide, thereby lowering the meltblowing temperature when manufacturing the meltblown fibers.

As described above, in the present embodiment, the melt-blown fiber including polyetherimide and polyimide as the polyetherimide imparting material has good heat resistance, flame retardancy, and dyeability, that is, the melt-blown nonwoven fabric has good heat resistance, flame retardancy, and dyeability.

The meltblown nonwoven fabric according to the present embodiment can be applied to a thermoplastic carbon fiber composite material. In detail, since the material of the meltblown fibers includes polyetherimide and polyimide with a glass transition temperature between about 128 ℃ and about 169 ℃, a 10% thermal weight loss temperature between about 490 ℃ and about 527 ℃, and a viscosity between about 171cP and about 250cP when dissolved in NMP and having a solid content of 30 wt%, the process of hot-pressing the meltblown nonwoven fabric with the carbon fiber fabric to manufacture the thermoplastic carbon fiber composite material can have the following advantages: the melt-blown non-woven fabric is heated uniformly, so that the process is fast, the resin impregnation property is increased, the processing process temperature is reduced due to the low melt-blown temperature of the melt-blown non-woven fabric, and the polyetherimide has the characteristics of unobvious thermal degradation and repeatable thermal processing, so that the polyetherimide has recycling economy.

In addition, in order to provide a melt-blown nonwoven fabric having good heat resistance, good flame retardancy, good chemical resistance, good heat shrinkage resistance, good dielectric properties, low process temperature and no occurrence of melt-drip phenomenon after combustion, the present invention provides another melt-blown nonwoven fabric which can achieve the above advantages. The following embodiments are merely examples of the present invention which can be actually carried out.

Another embodiment of the present invention provides a meltblown nonwoven fabric comprising a plurality of meltblown fibers adhered to one another. In particular, the plurality of meltblown fibers are randomly interlaced with respect to each other. In this embodiment, the basis weight of the meltblown nonwoven is between about 5g/m²To 100g/m²In the meantime.

In the present embodiment, the material of each of the plurality of meltblown fibers includes polyphenylene sulfide and polyimide. That is, the raw material of the meltblown nonwoven fabric is a master batch (i.e., a composition) including polyphenylene sulfide and polyimide. In detail, in the present embodiment, the method for producing the mother particle (i.e., the composition) including polyphenylene sulfide and polyimide includes mixing polyphenylene sulfide and polyimide by performing a hot melting process on polyphenylene sulfide and polyimide. The hot melting process utilizes heating and/or applying pressure to melt and bond together multiple materials (e.g., polyetherimide and polyimide). In this embodiment, the hot-melting process may include (but is not limited to): a melt-kneading granulation process, a hot-pressing process, a hot-air bonding process, or a melt-spinning process. In the present embodiment, the process temperature of the hot melting process may be between about 300 ℃ to about 350 ℃.

In the present embodiment, the meltblown nonwoven fabric can be produced by: a composition comprising polyphenylene sulfide and polyimide is melted at a high temperature, and the molten composition is ejected in a fibrous form from a spinning nozzle, and the ejected fibrous molten composition is drawn by a high-temperature high-speed gas, thereby obtaining a plurality of melt-blown fibers on a collecting device. In the present embodiment, the meltblown nonwoven fabric can be obtained by directly collecting a plurality of meltblown fibers. However, the invention is not limited thereto, and in other embodiments, the collected meltblown fibers may be processed by a hot pressing process to obtain a meltblown fiber nonwoven film (or meltblown fiber film).

In each of the meltblown fibers of the present embodiment, the polyimide may be present in an amount of about 1 to about 10 parts by weight, based on 100 parts by weight of polyphenylene sulfide. In other words, in the composition including polyphenylene sulfide and polyimide, the polyimide may be used in an amount of about 1 to about 10 parts by weight, based on 100 parts by weight of the polyphenylene sulfide. If the amount of polyimide used is less than 1 part by weight, the melt-blown fiber cannot be produced with significantly improved thermal processability of polyphenylene sulfide; on the other hand, if the amount of the polyimide is more than 10 parts by weight, the composition is poor in continuous processability, and it is difficult to produce a uniform melt-blown fiber nonwoven fabric or a film thereof.

Polyphenylene sulfide is a thermoplastic polymer. In the present embodiment, the polyphenylene sulfide may include a repeating unit represented by the following formula II:formula II. In the present embodiment, the polyphenylene sulfide may be a commercially available product, for example: PPS TR03G manufactured by large japan ink corporation. In addition, polyphenylene sulfide itself has good heat resistance, flame retardancy and chemical resistance, so that melt blown fibers made of materials including polyphenylene sulfide and polyimide have good heat resistance, flame retardancy and chemical resistance.

In this embodiment, the glass transition temperature of the polyimide is between about 128 ℃ to about 169 ℃, the 10% thermal weight loss temperature of the polyimide is between about 490 ℃ to about 534 ℃, and the viscosity is between about 100cP to about 250cP when the polyimide is soluble in NMP and has a solids content of about 30 wt%. If the glass transition temperature, 10% thermogravimetric loss temperature and viscosity of the polyimide do not fall within the above ranges, the thermoplastic composition obtained in the subsequent step is poor in thermal processability and thermal stability. In the present embodiment, the polyimide is an ether group-containing polyimide, whereby the high-temperature hot workability of the composition can be improved. In addition, in the present embodiment, the polyimide may include a repeating unit represented by formula 1:

wherein Ar is a tetravalent organic group derived from a tetracarboxylic dianhydride compound containing an aromatic group, and A is a divalent organic group derived from a diamine compound containing an aromatic group. That is, Ar is a tetracarboxylic dianhydride compound containing an aromatic group except 2 carboxylic anhydride groups (- (CO)₂A residue other than O); and A is a diamine compound containing an aromatic group except 2 amino groups (-NH)₂) Other residues. In the present embodiment, at least one of the tetravalent organic group and the divalent organic group contains an ether group. That is, at least one of the aromatic group-containing tetracarboxylic dianhydride compound and the aromatic group-containing diamine compound contains an ether group. Herein, the tetracarboxylic dianhydride compound containing an aromatic group is also referred to as a dianhydride monomer, and the diamine compound containing an aromatic group is also referred to as a diamine monomer. In the present embodiment, the polyimide can be obtained by reacting a dianhydride monomer with a diamine monomer.

In this embodiment, Ar may be Specifically, the dianhydride monomer used to prepare the polyimide may be BPADA, ODPA. PMDA, BTDA, or BPDA.

In this embodiment, A may be Specifically, the diamine monomer used for preparing the polyimide may be m-PDA, BAPP, 4 ' -diaminodiphenyl sulfone (4,4 ' -diaminodiphenyl sulfone), ODA, 3 ' -diaminobenzophenone (3,3 ' -diaminobenzophenone), TPE-R, 3,4 ' -diaminodiphenyl ether (3,4 ' -oxydianiline/3,4 ' -diaminodiphenyl ether), or DABA.

Specifically, in the present embodiment, the polyimide can be produced by, for example, a condensation polymerization method and a thermal cyclization method or a condensation polymerization method and a chemical cyclization method. The condensation polymerization method, the thermal cyclization method, and the chemical cyclization method can each be carried out by any step known to those skilled in the art. In one embodiment, the preparation of the polyimide by the condensation polymerization method and the chemical cyclization method may include the steps of: after a dianhydride monomer and a diamine monomer are subjected to a condensation polymerization reaction in a solvent to form a polyamic acid solution, a dehydrating agent and an imidizing agent are added to the polyamic acid solution to perform an imidization reaction (i.e., a dehydrative cyclization reaction) to form a polyimide. In another embodiment, the preparation of the polyimide by the condensation polymerization method and the thermal cyclization method may include the steps of: after a dianhydride monomer and a diamine monomer are subjected to a condensation polymerization reaction in a solvent to form a polyamic acid solution, the polyamic acid solution is heated to perform an imidization reaction (i.e., a dehydrative cyclization reaction) to form a polyimide.

The solvent is not particularly limited as long as it can dissolve the dianhydride monomer and the diamine monomer. Specifically, examples of the solvent include (but are not limited to): amide solvents such as DMAc, DMF, N' -diethylacetamide, NMP, γ -butyrolactone, hexamethylphosphoric triamide, and the like; urea solvents such as tetramethylurea and N, N-dimethylethylurea; sulfoxide or sulfone solvents such as dimethyl sulfoxide, diphenyl sulfone and tetramethyl sulfone; halogenated alkyl solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene; phenol solvents such as phenol and cresol; or ether solvents such as tetrahydrofuran, 1, 3-dioxolane, dimethyl ether, diethyl ether, and p-cresol methyl ether. The above solvents may be used alone or in combination of plural kinds. In order to improve the solubility and reactivity of the dianhydride monomer and the diamine monomer, the solvent is preferably an amide solvent such as DMAc, DMF, NMP, or the like. Additionally, examples of the dehydrating agents include (but are not limited to): acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride or trifluoroacetic anhydride; examples of such imidizing agents include, but are not limited to: pyridine, picoline, quinoline or isoquinoline.

In the present embodiment, the number of kinds of diamine monomers and the number of kinds of dianhydride monomers used to prepare the polyimide are not limited as long as the polyimide has a glass transition temperature of between about 128 ℃ and about 169 ℃, a 10% thermal weight loss temperature of between about 490 ℃ and about 527 ℃, and a viscosity of between 171cP and 250cP in the case where the solvent is NMP and the solid content is 30 wt%, and has appropriate hot melt processability and solvent solubility characteristics. For example, polyimides can be obtained by reacting a diamine monomer with a dianhydride monomer. For example, the polyimide may be obtained by reacting a plurality of diamine monomers with one dianhydride monomer, one diamine monomer with a plurality of dianhydride monomers, or a plurality of diamine monomers with a plurality of dianhydride monomers.

In the melt-blowing process of the present embodiment, the melt-blowing temperature of the melt-blown nonwoven fabric is between about 290 ℃ and about 310 ℃. Generally, in the process of preparing unmodified polyphenylene sulfide meltblown nonwoven fabric, the meltblowing temperature is between about 300 ℃ and about 320 ℃. In view of this, the meltblown nonwoven fabric of the present embodiment can be manufactured at a reduced meltblowing temperature.

In the melt-blowing process of the present embodiment, the high-temperature and high-velocity gas has a temperature of about 300 ℃ to about 350 ℃ and a draft pressure of about 3kg/cm²To about 7kg/cm²In the meantime. In addition, theThe high temperature and high velocity gas may be air or nitrogen.

In this embodiment, each meltblown fiber has a diameter between about 1 μm and about 10 μm. That is, the meltblown nonwoven fabric of the present embodiment may be composed of very fine microfibers.

In the present embodiment, the melt blown nonwoven fabric has a dielectric constant of between about 2.6 and about 2.9 and a dielectric loss of between about 0.0030 and about 0.0050 at a frequency of 10 GHz. That is, the meltblown nonwoven fabric of the present embodiment has good dielectric properties. Thus, the meltblown nonwoven fabric of the present embodiment is suitable for use as a substrate in a flexible printed circuit board. On the other hand, as mentioned above, the dielectric loss of the meltblown is between about 0.0030 and about 0.0050 at 10GHz, so the meltblown can meet the specification requirement of the fifth generation mobile communication system (5G).

In the present embodiment, the thermal shrinkage ratio of the meltblown nonwoven fabric after standing at a temperature of 140 ℃ for 24 hours is about 5% or less, and the thermal shrinkage ratio after standing at a temperature of 180 ℃ for 24 hours is about 10% or less. That is, the meltblown nonwoven fabric of the present embodiment has heat shrinkage resistance at high temperatures. In general, unmodified polyphenylene sulfide meltblown nonwoven fabrics are often used at high temperatures due to their high temperature resistance, but they have a thermal shrinkage phenomenon at high temperatures, for example, the thermal shrinkage ratio after standing at 140 ℃ for 24 hours is usually greater than 10%. In view of this, the meltblown nonwoven fabric of the present embodiment has good thermal shrinkage resistance at high temperature, compared to the conventional unmodified polyphenylene sulfide meltblown nonwoven fabric.

In this embodiment, the limiting oxygen index of the meltblown nonwoven is between about 29 and about 31. That is, the meltblown nonwoven fabric of the present embodiment has good flame retardancy.

It should be noted that, in the present embodiment, the meltblown nonwoven fabric includes a plurality of meltblown fibers made of polyphenylene sulfide and polyimide, and the glass transition temperature of the polyimide is between 128 ℃ and 169 ℃, the 10% thermogravimetric loss temperature of the polyimide is between 490 ℃ and 534 ℃, and the viscosity of the polyimide is between 100cP and 250cP when the polyimide is dissolved in NMP and the solid content is 30 wt%, so that the meltblown nonwoven fabric has good heat resistance, good flame retardancy, good chemical resistance, good thermal shrinkage resistance, good dielectric properties, low process temperature, and no occurrence of a melt-drip phenomenon after combustion.

In addition, in each of the meltblown fibers of the present embodiment, the polyimide is included in an amount of about 1 part by weight to about 10 parts by weight based on 100 parts by weight of the polyphenylene sulfide, so the polyphenylene sulfide may be considered as a main component, and the polyimide may be considered as a plasticizer for imparting good thermal processability to the polyphenylene sulfide, thereby reducing the meltblowing temperature when the meltblown fibers are manufactured.

As described above, in the present embodiment, the polyphenylene sulfide-providing material includes the melt-blown fiber of polyphenylene sulfide and polyimide, which has good heat resistance, flame retardancy, and chemical resistance, that is, the melt-blown nonwoven fabric has good heat resistance, flame retardancy, and chemical resistance.

As described above, in the present embodiment, the meltblown nonwoven fabric has good chemical resistance and is composed of very fine microfibers, and thus can be used as a filter membrane, or even as a filter membrane for an organic solvent.

Hereinafter, the features of the present invention will be described more specifically with reference to examples 1 to 3 and comparative examples 1 to 2. Although the following examples are described, the materials used, the amounts and ratios thereof, the details of the treatment, the flow of the treatment, and the like may be appropriately changed without departing from the scope of the present invention. Therefore, the present invention should not be construed restrictively by the examples described below.

Synthesis example 1

After the polyimide of Synthesis example 1 was formed according to the method for producing polyimide disclosed above, the polyimide of Synthesis example 1 was subjected to a glass transition temperature (Tg) and a 10% thermal weight loss temperature (T)_d10％) And measurement of viscosity. The description of the aforementioned measurement items is as follows, and the measurement results are shown in table 1.

< measurement of glass transition temperature (Tg) >

The polyimide of Synthesis example 1 was subjected to measurement of glass transition temperature (. degree. C.) under a nitrogen atmosphere and with a temperature rise rate of 10 ℃ per minute using a thermomechanical analyzer (model: DSC 200F 3, made by Maia corporation).

<10% thermal weight loss temperature (T)_d10％) Measurement of>

The polyimide of Synthesis example 1 was measured by thermogravimetric analysis (model: Q50, manufactured by TA instruments) under a nitrogen atmosphere at a temperature rise rate of 20 ℃/min and the change in weight of each polyimide was recorded, wherein the measured temperature at which each polyimide lost 10% by weight was 10% thermogravimetric loss temperature (. degree. C.).

< measurement of viscosity >

First, the polyimides of synthesis example 1 were dissolved in NMP as a solvent, respectively, to form a plurality of sample solutions having a solid content of 30 wt%. Next, the viscosity (cP) of the sample solutions was measured at room temperature by a rotary Viscometer (model: DV-II + Pro Viscometer, manufactured by Brookfield, USA).

TABLE 1

	Tg(℃)	Td10％(℃)	Viscosity (cP)
				Synthesis example 1	141	509	100

Example 1

The master batch of example 1 was prepared by the following procedure. 100 parts by weight of polyetherimide (ULTEM 1010PEI manufactured by Sabic basic industries, Ltd.) and 5 parts by weight of the polyimide of Synthesis example 1 were fed into a twin-screw extruder and melt-kneaded and pelletized at a temperature of 320 ℃ to obtain a master batch (i.e., a composition) of example 1.

Next, the master batch of example 1 was subjected to a melt-blowing process to manufacture the melt-blown nonwoven fabric of example 1, wherein the conditions of the melt-blowing process were as follows: the melt blowing temperature was about 345 ℃, the nozzle hole diameter was about 0.3mm, the high-temperature high-speed gas temperature was about 450 ℃, and the high-temperature high-speed gas draft pressure was about 7kg/cm²About 8rpm, and a collection distance of about 15 cm. The basis weight of the meltblown nonwoven fabric of example 1 was about 10g/m²The thickness of the meltblown nonwoven fabric of example 1 was about 0.022mm, and the average diameter of the meltblown fibers in the meltblown nonwoven fabric of example 1 was about 4 μm.

Example 2

The masterbatch of example 2 was prepared by the following procedure. 100 parts by weight of polyetherimide (ULTEM 1010PEI manufactured by Sabic basic industries, Ltd.) and 7 parts by weight of the polyimide of Synthesis example 1 were fed into a twin-screw extruder and melt-kneaded and pelletized at a temperature of 320 ℃ to obtain a master batch (i.e., a composition) of example 2.

Next, the master batch of example 2 was subjected to a melt-blowing process to manufacture the melt-blown nonwoven fabric of example 2, wherein the conditions of the melt-blowing process were as follows: the melt blowing temperature was about 350 ℃, the nozzle hole diameter was about 0.3mm, the high-temperature high-speed gas temperature was about 470 ℃, and the high-temperature high-speed gas draft pressure was about 7kg/cm²About 9rpm, and a collection distance of about 20 cm. The basis weight of the meltblown nonwoven of example 2 was about 15g/m²The thickness of the meltblown nonwoven fabric of example 2 was about 0.05mm, and the average diameter of the meltblown fibers in the meltblown nonwoven fabric of example 2 was about 10 μm.

Example 3

The masterbatch of example 3 was prepared by the following procedure. 100 parts by weight of polyphenylene sulfide (PPS TR03G manufactured by Dainippon ink Co., Ltd.) and 3.7 parts by weight of the polyimide of Synthesis example 1 were charged into a twin-screw extruder, and melt-kneaded and pelletized at a temperature of 300 ℃ to obtain a mother pellet (i.e., a composition) of example 3.

Next, the master batch of example 3 was subjected to a melt-blowing process to manufacture the melt-blown nonwoven fabric of example 3, wherein the conditions of the melt-blowing process were as follows: the melt blowing temperature was about 300 ℃, the nozzle hole diameter was about 0.3mm, the high-temperature high-speed gas temperature was about 320 ℃, and the high-temperature high-speed gas draft pressure was about 7kg/m²About 8rpm, and a collection distance of about 3 cm. The basis weight of the meltblown nonwoven of example 3 was about 90g/m²The thickness of the meltblown nonwoven fabric of example 3 was about 0.20mm, the average pore size of the meltblown nonwoven fabric of example 3 was about 2.54 μm, and the average diameter of the meltblown fibers in the meltblown nonwoven fabric of example 3 was about 1.9 μm.

Comparative example 1

In comparative example 1, the meltblown nonwoven fabric of comparative example 1 was produced by using polyphenylene sulfide (PPS TR03G produced by japan ink company (DIC)) alone as a base batch and performing a meltblowing process under the following conditions: the melt blowing temperature was about 300 ℃, the nozzle hole diameter was about 0.3mm, the high-temperature high-speed gas temperature was about 320 ℃, and the high-temperature high-speed gas draft pressure was about 7kg/m²About 8rpm, and a collection distance of about 6 cm. The basis weight of the meltblown nonwoven fabric of comparative example 1 was about 80g/m²The thickness of the meltblown nonwoven fabric of comparative example 1 was about 0.25mm, the average pore size of the meltblown nonwoven fabric of comparative example 1 was about 10.36 μm, and the average diameter of the meltblown fibers in the meltblown nonwoven fabric of comparative example 1 was about 4.3 μm. That is, in comparative example 1, a melt-blown nonwoven fabric was produced by directly using PPS TR03G manufactured by large japan ink corporation (DIC), a commercial product of polyphenylene sulfide.

Comparative example 2

In comparative example 2, the meltblown nonwoven fabric of comparative example 2 was produced by using polyphenylene sulfide (PPS TR03G produced by japan ink corporation (DIC)) alone as a base batch and performing a meltblowing process under the following conditions: melt blowing temperatureAbout 300 ℃, a nozzle diameter of about 0.3mm, a high-temperature high-speed gas temperature of about 320 ℃, and a high-temperature high-speed gas draft pressure of about 7kg/m²About 8rpm, and a collection distance of about 4 cm. The basis weight of the meltblown nonwoven fabric of comparative example 2 was about 80g/m²The thickness of the meltblown nonwoven fabric of comparative example 2 was about 0.25mm, and the average diameter of the meltblown fibers in the meltblown nonwoven fabric of comparative example 2 was about 10 μm. That is, in comparative example 2, a melt-blown nonwoven fabric was produced by directly using PPS TR03G, which is a commercially available product of polyphenylene sulfide.

Comparing the specification of the meltblown nonwoven fabric of example 3 with the specification of the meltblown nonwoven fabric of comparative example 1, it can be seen that under the same meltblowing conditions, the average diameter (1.9 μm) of the meltblown fibers in the meltblown nonwoven fabric of example 3 is smaller than the average diameter (4.3 μm) of the meltblown fibers in the meltblown nonwoven fabric of comparative example 1, and the average pore size (2.54 μm) of the meltblown nonwoven fabric of example 3 is smaller than the average pore size (10.36 μm) of the meltblown nonwoven fabric of comparative example 1. The results show that the material of the meltblown fibers of the present invention comprises polyphenylene sulfide and polyimide with glass transition temperature between about 128 ℃ and about 169 ℃, 10% thermal weight loss temperature between about 490 ℃ and about 527 ℃, and viscosity between about 171cP and about 250cP when dissolved in NMP and with a solid content of 30 wt% can have very fine fibers and small pore size.

In addition, the melt-blown nonwoven fabrics of examples 1 to 3 were measured for dielectric constant and dielectric loss, the melt-blown nonwoven fabrics of examples 1 to 3 were measured for limiting oxygen index, and the melt-blown nonwoven fabrics of example 3 and comparative example 2 were measured for thermal shrinkage ratio, tensile strength, and chemical resistance evaluation. The foregoing measurement items are described below, and the measurement results are shown in tables 2, 3,4, and 5.

Measurement of dielectric constant and dielectric loss

First, the meltblown nonwoven fabrics of examples 1 to 3 were produced into samples each having a length and width of 10cm × 10 cm. Next, the samples were respectively placed in an oven and baked at a temperature of 100 ℃ for 6 hours, and then a dielectric constant measuring apparatus (dielectric constant and dielectric loss of the samples were measured at a measuring frequency of 10 ghz. the measurement results are shown in table 2 below.

TABLE 2

	Dielectric constant	Dielectric loss
			Example 1	1.98～2.34	0.0025～0.0030
Example 2	1.8～2.4	0.0030～0.0050
			Example 3	2.6～2.9	0.0030～0.0050

As can be seen from Table 2, the meltblown nonwoven fabrics of examples 1-3 all had low dielectric constants and low dielectric losses, and the dielectric losses exhibited meet the 5G specification (i.e., dielectric loss (Df) was less than or equal to 0.0050). This result shows that the material of the melt-blown nonwoven fabric of the present invention includes polyetherimide and polyimide having a glass transition temperature, a 10% thermogravimetric loss temperature and a viscosity in a specific range when dissolved in NMP and having a solid content of 30 wt%, or polyphenylene sulfide and polyimide having a glass transition temperature, a 10% thermogravimetric loss temperature and a viscosity in a specific range when dissolved in NMP and having a solid content of 30 wt%, so that the melt-blown nonwoven fabric of the present invention has good dielectric properties.

Test of limiting oxygen index

The meltblown nonwoven fabrics of examples 1-3 were tested for Limiting Oxygen Index (LOI) according to ASTM D2863, and the results of each test are shown in table 3 below. Further, in the course of testing the limiting oxygen index, whether the melt-blown nonwoven fabrics of examples 1 to 3 have a melt-drip phenomenon after combustion was visually observed, and the respective evaluation results are also shown in the following table 3. Generally, the limiting oxygen index ≧ 28 indicates excellent flame retardancy.

TABLE 3

As is clear from Table 3 above, the limiting oxygen indexes of the meltblown nonwoven fabrics of examples 1 to 3 were 31, 31 and 34, respectively, and no molten drop phenomenon was caused after combustion. The results show that the material of the melt-blown non-woven fabric of the invention comprises polyetherimide and polyimide with glass transition temperature, 10% thermogravimetric loss temperature and viscosity in a specific range when the melt-blown non-woven fabric is dissolved in NMP and the solid content is 30 wt%, or polyphenylene sulfide and polyimide with glass transition temperature, 10% thermogravimetric loss temperature and viscosity in a specific range when the melt-blown non-woven fabric is dissolved in NMP and the solid content is 30 wt%, so that the melt-blown non-woven fabric of the invention has good flame retardant effect and can not cause melt dripping.

Measurement of thermal shrinkage ratio

First, the meltblown nonwoven fabrics of example 3 and comparative example 2 were produced into a plurality of square samples each having a length of 10 cm. Next, the samples of the meltblown nonwoven fabrics of example 3 and comparative example 2 were allowed to stand at 80 ℃, 140 ℃ and 180 ℃ for 24 hours, respectively, and then the length dimension of each sample was measured. Then, the heat shrinkage ratio of each sample was calculated by the following formula: the heat shrinkage ratio was 100% × [ (original nonwoven length-nonwoven length after 24 hours at a specific temperature)/original nonwoven length ]. The calculated results are shown in table 4 below. In table 4, the smaller the value, the better the heat shrinkage resistance of the melt-blown nonwoven fabric.

Measurement of tensile Strength

First, the melt-blown nonwoven fabrics of example 3 and comparative example 2 were each produced into a dumbbell-shaped or dog-bone-shaped sample having a length and width of 150mm × 25 mm. Next, the tensile strength (kgf) of these samples in the Machine Direction (MD) was measured using a tensile tester (model GT-7001-MC10, manufactured by high-speed railway inspection instruments) according to ASTM D5034, in which the tensile rate was 300 mm/min. The measurement results are shown in table 4 below. In table 4, the larger the value, the better the mechanical properties of the melt-blown nonwoven fabric.

TABLE 4

As is clear from table 4 above, the meltblown nonwoven fabric of example 3 exhibited better heat shrinkage resistance after standing at 140 ℃ and 180 ℃ for 24 hours, compared to the meltblown nonwoven fabric of comparative example 2, which was made using polyphenylene sulfide alone. This result shows that the heat shrinkage resistance of the melt-blown nonwoven fabric of the present invention is improved by using a material of the melt-blown fiber including polyphenylene sulfide and polyimide having a glass transition temperature, a 10% thermal weight loss temperature, and a viscosity in a specific range when dissolved in NMP and having a solid content of 30 wt%.

As is clear from table 4 above, the meltblown nonwoven fabric of example 3 and the meltblown nonwoven fabric of comparative example 2 have similar tensile strengths. This result shows that the material of the meltblown fiber of the present invention includes polyphenylene sulfide and glass transition temperature, 10% thermogravimetric loss temperature and polyimide having viscosity in a specific range when dissolved in NMP and having a solid content of 30 wt%, and the meltblown nonwoven fabric manufactured using only polyphenylene sulfide has similar mechanical properties.

Evaluation of chemical resistance

First, the meltblown nonwoven fabrics of example 3 and comparative example 2 were each produced into a plurality of samples each having a weight of 10 g. Next, the samples of the melt-blown nonwoven fabrics of example 3 and comparative example 2 were immersed in various different chemical solvents at a specific temperature for a specific time, and then the weight (g) of each sample was measured. Thereafter, the weight loss of each sample was calculated by the following formula: the weight loss was 100% × [ (weight after sample immersion-weight before sample immersion)/weight before sample immersion ], and the resistance was evaluated according to the following resistance evaluation criteria. The soaking conditions and evaluation results of each sample are shown in table 5 below.

< evaluation criteria for chemical resistance >

O: the weight loss is 0 percent

X: the weight loss is not equal to 0 percent

TABLE 5

As is clear from table 5, the meltblown nonwoven fabric of example 3 and the meltblown nonwoven fabric of comparative example 2 were not subjected to weight loss after being immersed in an acid-base chemical solvent at a specific temperature for a specific time. That is, the fiber structures of the meltblown nonwoven fabric of example 3 and the meltblown nonwoven fabric of comparative example 2 were not corroded by the acid-base chemical solvent. This result shows that the material of the meltblown fiber of the present invention includes polyphenylene sulfide and glass transition temperature, 10% thermogravimetric loss temperature and polyimide having viscosity in a specific range when dissolved in NMP and having a solid content of 30 wt%, and the meltblown nonwoven fabric manufactured using only polyphenylene sulfide has similar and good chemical resistance.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.