KR101672461B1 - Composition of non-woven fabric having molten cellulose ultrafine-fiber, Non-woven fabric having molten cellulose ultrafine-fiber using the same and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a melt-cellulose ultrafine nonwoven fabric composition, a molten cellulose ultrafine nonwoven fabric and a process for producing the same. More specifically, the present invention provides a melt-cellulose ultrafine nonwoven fabric having pores in a fiber and containing a fiber aggregate of a bulky structure A nonwoven fabric prepared using the same, and a method for producing the same, and further relates to an application product thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a meltblown cellulose-based meltblown fiber composition for a sound-absorbing material nonwoven fabric, a molten cellulose ultrafine nonwoven fabric using the same, and a method for producing the meltblown cellulose ultrafine- Manufacturing method thereof}

The present invention relates to a composition capable of producing a molten cellulose ultrafine nonwoven fabric having pores in a fiber constituting the nonwoven fabric and containing a fibrous aggregate having a bulky structure, an ultrafine nonwoven fabric produced using the same, and a method for producing the same. And further relates to an application product thereof.

Such as a vacuum cleaner, a dishwasher, a washing machine, an air conditioner, an air purifier, a computer, a projector, and the like, and the problem of noise pollution becomes more serious. Therefore, efforts to block or reduce the noise generated from various noise sources in the modern life are continuing, and in the developed countries, the legal regulations to regulate the noise level between the interlayer and the generation of apartment houses and apartments are increasingly strict . In addition, the noise introduced into the automobile interior is typically generated by the engine, such as the engine noise transmitted through the vehicle body or the air, and the friction sound with the wheel and the ground. In order to suppress such noise, the engine cover and the hood insulation are used The effect of reducing the noise is insignificant, and the dash outer, the dash inner, and the floor carpet attached to the outside of the vehicle play a role of removing most of the noise.

There are two ways to improve the noise. One is to improve the sound absorption performance and the other way to improve the sound insulation performance. Sound absorption is the sound energy that is transmitted through the inner path of the material and is converted into heat energy and disappears. And is reflected and shielded by the shield.

Felt, sponge, polyurethane foam and the like are conventionally used as suction and sound insulating materials conventionally used. In addition, sound absorbing materials impregnated with a thermoplastic resin or a thermosetting resin in compressed fiber, glass fiber, rock surface, or regenerated fiber are listed . However, most of the sound absorbing materials described above have insufficient soundproofing ability, and most of the sound absorbing materials contain harmful components to the human body.

In recent years, regulations on the environment-friendly and recyclability have been gradually strengthened, and the use ratio of the thermoplastic resin-based fiber-absorbing material is increasing. In order to reduce carbon dioxide, the regulation of fuel efficiency of the vehicle is gradually increasing. The improvement of fuel efficiency can be attained through the weight reduction of parts, so it is necessary to develop lightweight sound absorbing material with improved performance.

Accordingly, research and development on a sound absorbing material which is harmless to the human body and excellent in the sound absorbing function capable of effectively absorbing and reducing the noise while reducing the thickness has been actively conducted.

As a sound absorbing material which has been conventionally researched and developed, there is disclosed a sound absorbing material (U.S. Patent Publication No. 1954-433600) which is a web type in which general short fibers having a diameter of 10 탆 or more are crimped to a general meltblown fiber in an amount of 10% Discloses a sound absorbing material and a heat insulating material which are webs formed of a meltblown fiber containing bulky fibers that are crimped. However, since the porosity of a web made of a general meltblown fiber is very large, the structure of the web is insufficient and the durability of the sound absorbing material is insufficient There is a problem that the thickness of the sound absorbing material must be greatly increased in order to provide a sufficient sound absorbing effect as well as not providing a sufficient sound absorbing effect.

Although a three-dimensional nonwoven web made of a meltblown microfine fiber is disclosed, a three-dimensional nonwoven web has a large porosity and thus is not densely structured to have a poor durability. It is necessary to increase the thickness of the three-dimensional nonwoven web significantly, and it is difficult to manufacture the nonwoven web composed of three dimensions as described above, which increases the manufacturing cost significantly. In addition, a sound absorbing material is also disclosed, which includes staple fibers that can be fused to the meltblown fibers by heat to impart three-dimensional stability. However, such a sound absorbing material still has a problem of insufficient sound insulation performance. In addition, a sound absorbing material using a honeycomb structure having a plurality of spaces together with meltblown fibers has been disclosed. However, such a sound absorbing material is insufficient in soundproof performance and has a problem in that it is limited in its application because of lack of flexibility.

Korean Published Patent Application No. 10-2011-0122566 (published on November 10, 2011) Korean Patent Publication No. 10-2010-0015043 (Published on February 12, 2010)

An object of the present invention is to provide a novel ultrafine nonwoven fabric composition capable of increasing the specific surface area of a fiber by forming pores in a fiber constituting a nonwoven fabric which is a sound absorbing material and an ultrafine nonwoven fabric And to provide an ultrafine nonwoven fabric.

Disclosure of the Invention In order to solve the above-mentioned problems, the present invention relates to a melt-cellulose ultrafine nonwoven fabric composition comprising a mixture comprising a thermoplastic cellulose ester resin and a plasticizer; Radical generation inhibitors; And a radical activity inhibitor.

In one preferred embodiment of the present invention, the molten cellulose ultrafine nonwoven fabric composition of the present invention is prepared by mixing 100 parts by weight of a mixture containing 50 to 75% by weight of a thermoplastic cellulose ester resin and 25% by weight to 50% by weight of a plasticizer, To 2 parts by weight of the radical inhibitor and 0.001 to 2.5 parts by weight of the radical activity inhibitor.

As a preferred embodiment of the present invention, in the composition of the present invention, the thermoplastic cellulose ester resin may have a degree of substitution of cellulose hydroxyl groups of 1.5 to 4.0 and a weight average molecular weight of 10,000 to 42,000.

As a preferred embodiment of the present invention, in the composition of the present invention, the thermoplastic cellulose ester resin is selected from the group consisting of cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose acetate caproate, Cellulose acetate palmitate, cellulose acetate stearate, and cellulose acetate oleate, as well as at least one selected from cellulose acetate succinate, cellulose acetate laurethate, cellulose acetate palate, cellulose acetate palate, cellulose acetate stearate and cellulose acetate oleate.

As a preferred embodiment of the present invention, in the composition of the present invention, the plasticizer is selected from polyethylene glycol, polypropylene glycol, polyglycolic acid, polybutyl adipate, glycerin and tributyl sebacate having a weight average molecular weight of 100 to 350 And at least one selected from the group consisting of

In a preferred embodiment of the present invention, in the composition of the present invention, the radical generation inhibitor may include a water-insoluble compound containing a phenol group.

In one preferred embodiment of the present invention, the radical generation inhibitor is tetrakis (methylene) (3,5-di-t-butyl- (3,5-di-t-butyl-4-hydroxyphenyl) propionate methane. .

In a preferred embodiment of the present invention, in the composition of the present invention, the radical activity inhibitor may include a phosphorus-containing water-insoluble compound at the terminal.

In one preferred embodiment of the present invention, the radical activity inhibitor comprises at least one selected from tris (2,4-di-t-butylphenyl) phosphite and tris-nonylphenyl phosphite and triphenyl phosphite .

In one preferred embodiment of the present invention, the molten cellulose ultrafine nonwoven fabric composition of the present invention may further comprise a carbodiimide-based hydrolysis inhibitor. The content of the molten cellulose ultrafine nonwoven fabric composition may be in the range of 0.05 to 100 parts by weight based on 100 parts by weight of the thermoplastic cellulose ester resin and plasticizer. To 2.5 parts by weight.

Another object of the present invention is to provide a melt-cellulose ultrafine nonwoven fabric prepared by using the melt-cellulose ultrafine nonwoven fabric composition of the present invention in various forms described above, and it includes meltblown cellulose ester-based meltblown fibers having an average diameter of 2.5 탆 to 5 탆 And the meltblown fibers have a number of micropores having an average particle diameter of 100 nm to 600 nm.

In one preferred embodiment of the present invention, the melt-cellulose ultrafine nonwoven fabric of the present invention may have a plasticizer content of 0.2 wt% or less, preferably no plasticizer.

In one preferred embodiment of the present invention, the meltblown fibers constituting the melt-cellulose ultrafine nonwoven fabric of the present invention have an MI (melt index) of 140 to 170 g / 10 min (250 ° C) 5 mu m.

In one preferred embodiment of the present invention, the melt-cellulose ultrafine nonwoven fabric of the present invention has an average average area density of 20 g / m ² to 400 g / m ² .

In one preferred embodiment of the present invention, the melt-cellulose ultrafine nonwoven fabric of the present invention has an average surface density of 300 g / m < ² >, an absorption coefficient at 1,000 Hz according to the ISO cabinet method of R 354, A coefficient of 0.85 or more, and a sound absorption coefficient at 2,000 Hz of 0.95 or more.

As a preferred embodiment of the present invention, the melt-cellulose ultrafine nonwoven fabric according to the present invention has an average surface density of 300 g / m ² and an absorption coefficient of 3,150 Hz according to ISO R 354 alpha cabin method, A coefficient of 1.00 or more, and a sound absorption coefficient at 5,000 Hz of 1.08 or more.

It is still another object of the present invention to provide a method for producing the above-mentioned melt cellulose ultrafine nonwoven fabric, which comprises chip-forming various types of thermoplastic cellulose ultrafine nonwoven fabric compositions as described above and melting the same to prepare a molten resin, Melt spinning to prepare a meltblown fiber aggregate, sonicating it to elute the plasticizer, followed by saponification and drying.

As a preferred embodiment of the present invention, the method for producing the microcellular microcellulose nonwoven fabric according to the present invention comprises the steps of: preparing a mixed resin by mixing a thermoplastic cellulose ultrafine nonwoven fabric composition; Drying the mixed resin at 70 ° C to 90 ° C for 20 to 30 hours to prepare a thermoplastic cellulose ester chip; Adding the thermoplastic cellulose ester chip to a kneader and blending the kneaded mixture under a condition of raising the internal temperature of the kneader from 150 ° C to 220 ° C to prepare a melted cellulose ester resin; Melt spinning the melted cellulose ester resin through a meltblown die and a spinneret while simultaneously producing a meltblown fiber aggregate using hot air at a high temperature and a high pressure; And immersing the meltblown fiber aggregate in water, followed by sonication to elute the plasticizer; Immersing the meltblown fibrous aggregate from which the plasticizer has been eluted in an aqueous solution of NaOH at a concentration of 5 to 15 vol% for 60 to 120 minutes, And a step of drying the sintered meltblown fibrous aggregate to produce the ultrafine nonwoven fabric of the present invention.

As a preferred embodiment of the present invention, in the production method of the present invention, the blending of the step of producing a molten cellulose ester resin is carried out at 20 to 30 kg / hr of a circle feeder and at a kneader motor speed of 220 rpm to 300 rpm . ≪ / RTI >

In a preferred embodiment of the present invention, the melt-cellulose ester resin in the step of preparing the melt-cellulose ester resin may have a melt temperature of 200 ° C to 300 ° C.

As a preferred embodiment of the present invention, in the production method of the present invention, the meltblown die and the spinneret are carried out at a temperature of 230 ° C. to 280 ° C. and a hot air temperature of 240 ° C. to 270 ° C. .

In addition, in a preferred embodiment of the present invention, the melt-blown fiber is produced by a spinneret having a cross-section and a composite spinneret, wherein the spinneret has a cruciform section, a polygonal section, The composite spinneret may be characterized by a side by side, a sheath - core, a sea - island cross - section, (Sea Island) and split type.

In one preferred embodiment of the present invention, in the method of the present invention, the temperature of water in the step of eluting the plasticizer is 50 ° C. to 70 ° C., and the ultrasound intensity during ultrasonic treatment is 300 Hz to 400 Hz can do.

Another object of the present invention is to provide a sound absorbing material using the melt-cellulose ultrafine nonwoven fabric as described above, and the sound absorbing material can be used as an automobile interior material, a refrigerator, an air conditioner, a sound absorbing material for electric equipment,

The above-described melt-cellulose ultrafine nonwoven fabric of the present invention may also be used as a filter media.

The above-described melt-cellulose ultrafine nonwoven fabric of the present invention can also be used as a cosmetic mask sheet.

The melt-cellulose ultrafine nonwoven fabric of the present invention uses fibers of cellulosic material, which is a biomass-derived material, and uses an environmentally-friendly plasticizer. The microcellular fibrous aggregate is produced without using a wet process using a conventional organic solvent And the specific surface area is increased by the pore structure formed on the surface of the fiber in the nonwoven fabric, so that not only the high frequency but also the sound absorbing property to low frequency is excellent. In addition, the nonwoven fabric of the present invention can be applied to a cosmetic mask sheet using the nonwoven fabric of the present invention using such a high specific surface area, and can also be applied as a filter media. Particularly, It is suitable for application as a sound absorbing material for built-in mobile means such as a car, an airplane, a boat, a sound absorbing material for electronic parts such as a mobile phone, a notebook computer, a computer, a TV, a refrigerator and an air conditioner,

Figs. 1 and 2 are SEM photographs of fibers of the fiber aggregate prepared in Example 1. Fig.

Hereinafter, the present invention will be described in more detail.

The melt-cellulose ultrafine nonwoven fabric composition of the present invention includes a thermoplastic cellulose ester resin, a plasticizer, a radical formation inhibitor and a radical activity inhibitor.

The composition comprises a cellulose ester resin and is a cellulose derivative in which a part or all of the hydroxyl groups of the cellulose are substituted by ester bonds, so that the strong hydrogen bonds of the cellulose hydroxyl are weakened so that the plasticizer can be mixed well therebetween. Further, as the plasticizer is mixed effectively, strong hydrogen bonding due to the hydroxyl group of the cellulose may be interfered and melt spinning may be possible.

In the present invention, the thermoplastic cellulose ester resin is preferably selected from the group consisting of cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose acetate caproate, cellulose acetate caprylate, cellulose acetate laurethate, cellulose acetate Palmitate, cellulose acetate stearate or cellulose acetate oleate, or the like. The cellulose ester resin of the present invention may have a weight average molecular weight of 10,000 to 42,000, a degree of substitution of 1.5 to 4.0, preferably a weight average molecular weight of 20,000 to 40,000 and a degree of substitution of 1.7 to 3.0, More preferably a weight average molecular weight of 25,000 to 32,000 and a degree of substitution of 2.0 to 2.6. The substitution degree of the cellulose ester resin means the degree of substitution of the hydroxyl group of the cellulose by the ester bond. When the degree of substitution of the cellulose ester resin is less than 1.5, the flowability of the molecules may be lowered during the melting, There is a problem that the melt viscosity decreases and the fiber forming ability is lowered as well as the frequency of threading is increased due to the hot air accompanying the meltblown fiber manufacturing process.

In addition, the composition of the present invention may contain a plasticizer in addition to the thermoplastic cellulose ester resin. The plasticizer is not particularly limited as long as it is mixed with a thermoplastic cellulose ester resin to prevent strong hydrogen bonding due to hydroxyl groups present in the cellulose ester and to allow melt spinning. Preferably, the plasticizer has a weight average molecular weight of 350 , Preferably having a weight average molecular weight of 100 to 250, and more preferably having a weight average molecular weight of 150 to 220 can be used. At this time, if the weight average molecular weight of the plasticizer exceeds 350, the meltblown plasticizing efficiency may be lowered, and the average diameter and fineness of the fiber aggregate prepared from the composition of the present invention may increase, .

Examples of the plasticizer include aromatic polycarboxylic acid esters such as dibutyl adipate, dioctyl adipate, dibutyl sebacate, dioctyl sebacate, diethyl azelate, dibutyl azelate and dioctyl azelate; Lower fatty acid esters of polyhydric alcohols such as glycerin triacetate, diglycerin tetraacetate and polyglycolic acid; Phosphoric acid esters such as triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate and tricresyl phosphate; Aliphatic polyesters composed of glycols and dibasic acids such as polyethylene glycol, polypropylene glycol, polyethylene adipate, polybutylene adipate, polyethylene succinate, and polybutylene succinate; Aliphatic polyesters composed of oxycarboxylic acids such as polyglycolic acid; And aliphatic polyesters composed of lactones such as polycaprolactone, polypropiolactone, and polar valerolactone; , And the like. Preferably, at least one selected from polyethylene glycol, polypropylene glycol, polyglycolic acid, polybutyl adipate, glycerin and tributyl sebacate having a weight average molecular weight of 350 or less, preferably polyethylene terephthalate having a weight average molecular weight of 350 or less Glycol, polypropylene glycol, and polyglycolic acid.

The content of the plasticizer in the total weight of the mixture of the thermoplastic cellulose ester resin and the plasticizer is 25 wt% to 50 wt%, preferably 30 wt% to 50 wt%, more preferably 35 wt% to 45 wt% When the amount of the plasticizer used is less than 25% by weight in the total weight of the mixture, the pores may not be formed well in the fibers melt-spun due to the strong hydrogen bonding of the cellulose, , The mechanical properties of the nonwoven fabric are greatly reduced due to too much pores in the fibers, breed-out of the plasticizer on the fiber surface occurs, and a large amount of the plasticizer in the nonwoven fabric remains, .

The melt-cellulose ultrafine nonwoven fabric composition of the present invention includes a radical generation inhibitor and a radical activity inhibitor, wherein the radical generation inhibitor is decomposed by heat when the cellulose ester resin is thermally or when the plasticized cellulose ester resin is pre- And the chain serves to suppress radical generation which is generated at the tip, so that it is possible to spin at a high temperature, and it is possible to provide melt-spun fibers and / or fiber aggregates having excellent physical properties . The radical generation inhibitor may be in the form of a liquid or solid phase which is easily mixed with a cellulose ester resin and a plasticizer, and may be the same as a water-insoluble compound containing a phenol group, preferably tetrakis methylene (3,5-di (3,5-di-t-butyl-4-hydroxycinnamate) methane, pentaerythritol tetrakis (3- Di-t-butyl-4-hydroxyphenyl) propionate methane, and more preferably at least one selected from tetrakis methylene (3,5-di-t- Methane) methane can be used. As a specific example, at least one selected from Anox 20 (Chemtura Co.), Iganox 1010 (Ciba Specialty Chemicals, Inc.) and Songnox 1010 (Songwon Industrial Co., Ltd.) .

The radical generation inhibitor may be used in an amount of 0.01 to 2 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the mixture. If the amount is less than 0.01 part by weight, the cellulose ester resin The cellulose ester resin may be thermally decomposed in the course of thermogravization or spinning. If the amount exceeds 2 parts by weight, there may be a problem in workability as a cause of an increase in pack pressure.

By using not only the radical generation inhibitor but also a radical activity inhibitor, the present invention can provide a molten radiator having a low defective rate and excellent physical properties. In the present invention, the radical generation inhibitor plays a role in preventing oxidation of the melt-spun fiber in the atmosphere and inhibits the radical generation generated by breaking of the cellulose main chain. The radical activity inhibitor may be in the form of a liquid or solid phase which is easily mixed with a cellulose ester resin and a plasticizer, and may be a water-insoluble compound containing an elemental phosphorus at the terminal, and preferably tris (2,4-di- Phenyl) phosphite, and tris (2,4-di-t-butylphenyl) phosphite can be used, more preferably at least one selected from tris (2,4-di-t-butylphenyl) phosphite and tris-nonylphenyl phosphite and triphenyl phosphite. Specific examples include at least one selected from Alkanox 240 (Chemtura Co.), Igafos 168 (Ciba Specialty Chemicals, Inc.) and Songnox 1680 (Songwon Industrial Co., Ltd).

The radical scavenging agent may be used in an amount of 0.001 to 2.5 parts by weight, preferably 0.05 to 0.8 part by weight, based on 100 parts by weight of the mixture. If the amount is less than 0.001 part by weight, The cellulose ester resin melted in the thermoplastic or melt spinning process may be thermally decomposed. If the amount exceeds 2.5 parts by weight, there may be a problem in workability and moldability due to an increase in pack pressure.

In addition, the molten cellulose ultrafine nonwoven fabric composition of the present invention may further include a hydrolysis inhibitor in addition to the plasticizer, the radical formation inhibitor and the radical activity inhibitor. The hydrolysis inhibitor prevents the decomposition of the chain of the polymer due to hydrolysis caused by a certain amount of water present in the thermoplastic cellulose composition (or the melted resin) plasticized in the high temperature heat treatment process. When the molten cellulose ultrafine nonwoven fabric composition is melted prior to melt spinning, the moisture content of the nonwoven fabric can be increased by the hydrolysis prevention effect and the drying time can be shortened . Specifically, if the conventional moisture content control standard is 500 ppm or less, the moisture content control standard of the present invention can be 1,000 to 3,000 ppm, and the drying process time can be shortened. Furthermore, it is possible to prevent further hydrolysis, which may be caused by a part of the residual moisture content, and thereby to improve poor workability due to viscosity drop. In the present invention, the hydrolysis inhibitor is a carbodiimide type And preferably a bis-carbodiimide comprising a compound represented by RN = C = NR and / or RN = C = N = R can be used. Wherein R and R 'represent a substituted or unsubstituted alkyl group having ₄ to ₂₀ carbon atoms, or substituted or unsubstituted aryl groups, wherein the substituent is selected from the group consisting of a halogen atom, a nitro group, an amino group, a sulfone group, a hydroxyl group, , Or an alkoxy group, and R and R 'may be the same or different.

Examples of the above-mentioned bis-carbodiimide include bis-carbodiimide manufactured by Rhein-Chemie GmbH of Germany under the trade name of TABAXOL, and 2,2 ', 6,6'- A copolymer of tetraisopropyldiphenylcarbodiimide and 2,6-diisopropyldiisocyanate of 2,4-diisocyanate-1,3,5-tris (1-methylethyl) And aromatic polycarbodiimides such as 2,2,4-diisocyanato-1,3,5-tris (1-methylethyl) homopolymer, and more preferably 2,2 ' , 6,6'-tetraisopropyldiphenylcarbodiimide and benzene-2,4-diisocyanato-1,3,5-tris (1-methylethyl) can be used.

The amount of the hydrolysis inhibitor to be used in the present invention is 0.5 to 2.5 parts by weight, preferably 0.8 to 2.3 parts by weight, more preferably 0.8 to 1.8 parts by weight, based on 100 parts by weight of the mixture containing the thermoplastic cellulose ester resin and the plasticizer When the amount is less than 0.5 part by weight, the effect of preventing the hydrolysis of cellulose may be insufficient. When the amount is more than 2.5 parts by weight, it is economically inefficient.

Hereinafter, a method for producing a melt-cellulose ultrafine nonwoven fabric using the melt-cellulose ultrafine nonwoven fabric composition of the present invention will be described.

The melt-cellulose ultrafine nonwoven fabric of the present invention is obtained by forming the above-mentioned thermoplastic cellulose ultrafine nonwoven fabric composition into chips, melting the resultant to prepare a molten resin, melting the resultant, and passing it through hot air After the meltblown fiber aggregate is prepared, it is ultrasonicated to elute the plasticizer present in the fiber aggregate, followed by saponification and drying of the fiber aggregate from which the plasticizer has eluted.

More specifically, the molten cellulose ultrafine nonwoven fabric of the present invention comprises: mixing a thermoplastic cellulose ultrafine nonwoven fabric composition to prepare a mixed resin; Drying the mixed resin to produce a thermoplastic cellulose ester chip; Adding the thermoplastic cellulose ester chip to a kneader and blending the kneaded mixture under a condition of raising the internal temperature of the kneader from 150 ° C to 220 ° C to prepare a melted cellulose ester resin; Melting the melted cellulose ester resin to produce meltblown fibrous aggregates through hot air in a process of passing the melted cellulose ester resin through a die and a spinneret; And immersing the meltblown fiber aggregate in water, followed by sonication to elute the plasticizer; A step of sorbing the meltblown fibrous aggregate from which the plasticizer has been eluted; And a step of drying the sintered meltblown fibrous aggregate to produce the ultrafine nonwoven fabric of the present invention.

The thermoplastic cellulose ester resin, the plasticizer, the radical formation inhibitor and the radical activity inhibitor in the step of preparing the mixed resin are the same as the types and composition ratios of the melt-cellulose ultrafine nonwoven fabric described above.

The drying of the step of preparing the thermoplastic cellulose ester chip may be carried out by using a general method used in the art, preferably at 70 ° C to 90 ° C for 20 to 30 hours, more preferably at 75 ° C to 85 ° C, The hot air drying can be performed for about 26 hours. If the drying temperature is less than 70 ° C., the drying time may become too long to lower the commerciality, and the mixed resin may not be converted into a chip. If the drying temperature exceeds 90 ° C., fusion may occur .

In the step of producing the melted cellulose ester resin, the blending is preferably performed at a temperature in the range of from 160 ° C to 210 ° C, more preferably at 165 ° C If the internal temperature of the kneader is less than 150 ° C, the plasticizer is not sufficiently melted and is not uniformly mixed. As a result, since the plasticizer is not uniformly present in the chip, the meltblown fibers There may be a problem of increasing the defective rate in the manufacturing process, and if it is more than 220 ° C, there may be a problem of causing physical degradation of the fiber due to thermal decomposition, so blending is preferably performed in the temperature range.

The blending is preferably carried out at a speed of 20 kg / hr to 30 kg / hr of the circle feeder and at a speed of 220 rpm to 300 rpm of the kneader, preferably 22 kg / hr to 28 kg / hr of the circle feeder, It is advantageous in the homogeneous phase implementation to perform at a speed of 240 rpm to 290 rpm.

The blended molten cellulose ester resin can be applied to meltblown and spunbond nonwoven fabrics from filament and staple fibers through melt spinning at a melting temperature of 200 ° C to 300 ° C for processing into fiber form.

In the step of producing the meltblown fiber aggregate, it is preferable that the temperature of the spinneret and the die is performed at 230 to 290 ° C, preferably at a spinning temperature of 240 to 280 ° C, It is preferable to perform the heating at 255 ° C to 275 ° C, and the hot air temperature is preferably set to be higher by about 10 ° C than the die and the holding temperature. If the spinning temperature is less than 230 ° C, the fineness of the meltblown fibers may become thick, which may cause a problem in manufacturing a very fine nonwoven fabric. If the spinning temperature is higher than 290 ° C, the meltblown fibers are broken during the spinning process, It is preferable to perform the meltblown fiber production under the above-mentioned temperature range since there is a problem that the quality of the nonwoven fabric is deteriorated and the quality of the nonwoven fabric is decreased.

In addition, the detachment used for the meltblown spinning may be a general detachment used in the art, preferably a deformed section and a composite spinneret. The deformed section detachment may be a cross-section detachment, a polygonal The composite spinneret may be characterized by a side by side, a sheath core, a C-shaped cross-section, a round cross-section, a cross-section cross-section, Core, Sea Island, and Split Detention.

The melt-spun meltblown fibers constituting the meltblown fiber aggregate may have an average diameter of 2.5 탆 to 5.0 탆, preferably 3.0 탆 to 5.0 탆, more preferably 4.0 탆 to 5.0 탆, Is less than 2.5 탆, the mechanical properties of the nonwoven fabric are not only low but also the sound absorption properties may be deteriorated. If the average diameter of the fibers exceeds 5 탆, there is a problem that the sound absorption properties are decreased. The meltblown fibers have a melt index (MI) of 140 to 170 g / 10 min (250 ° C), preferably an MI of 145 to 165 g / 10 min (250 ° C), more preferably 150 to 160 g / Min < / RTI > (250 DEG C).

The step of eluting the plasticizer may be performed by removing the plasticizer present in the meltblown fiber aggregate by immersing the meltblown fiber aggregate in water, followed by ultrasonic treatment. At this time, the temperature of the water is preferably 50 ° C to 70 ° C, more preferably 55 ° C to 65 ° C, from the viewpoint of ease of elution and processing of the plasticizer. The ultrasonic treatment may be performed by applying ultrasonic waves of 300 Hz to 400 Hz intensity, preferably 320 Hz to 400 Hz intensity, more preferably 340 Hz to 380 Hz intensity. At this time, If the ultrasonic intensity is less than 300 Hz, the plasticizer may not be eluted and the ultrasonic treatment time may become too long. If the ultrasonic intensity exceeds 400 Hz, there may be a problem of deteriorating the fiber properties. Therefore, It is preferable to perform ultrasonic treatment.

As a preferable example of the ultrasonic treatment, water having a temperature of about 50 ° C to 70 ° C is filled in a water tank communicating with three upper parts and three lower parts, ultrasonic waves are applied in a water tank at a frequency of 300 Hz to 400 Hz, And allowing the fiber aggregate to pass through the water tank at a rate of 750 to 1100 mpm for 15 to 30 seconds.

When the step of eluting the plasticizer is performed, the plasticizer may be present in the meltblown fiber aggregate in an amount of 0.2 wt% or less, preferably 0.01 to 0.2 wt%, more preferably 0 to 0.05 wt% .

The step of hydrolyzing may be performed by immersing the melted fibrous aggregate in which the plasticizer has been dissolved in an aqueous solution of NaOH for 60 to 120 minutes. The NaOH aqueous solution is preferably an aqueous solution of 5 to 20% by volume of NaOH, preferably 5 It is preferable to use an NaOH aqueous solution with a concentration of 15 to 15 vol% and more preferably a NaOH aqueous solution with a concentration of 8 to 12 vol%. If the concentration of the aqueous NaOH solution is less than 5 vol%, the saponification does not sufficiently take place, There may be a problem that the residual amount of the plasticizer is deteriorated and the strength of the plasticizer may be deteriorated. If the concentration of the aqueous NaOH solution exceeds 20% by volume, there may be a problem of deteriorating the overall fiber properties including strength. Therefore, It is good to use.

The drying of the sintered meltblown fibrous aggregate can be carried out through a drying process common in the art.

1 and 2 of the present invention, the meltblown fibers constituting the molten cellulose ultrafine nonwoven fabric have pores and can have a high specific surface area.

The melt-cellulose ultrafine nonwoven fabric of the present invention comprises melt-cellulose ester-based meltblown fibers having an average diameter of 2.5 to 5 m, and the meltblown fibers have an average particle diameter of 100 nm to 600 nm, preferably an average particle diameter of 200 And a plurality of micropores having a diameter of 500 nm to 500 nm are formed.

As described above, the melt-cellulose ester-based meltblown fibers have an MI (melt index) of 140 to 170 g / 10 min (250 ° C) and have a diameter of 2.5 to 5 μm.

The melt-cellulose ultrafine nonwoven fabric of the present invention has an average area density of 250 to 400 g / m ² , preferably an average area density of 270 to 380 g / m ² , more preferably an average area density of 280 to 350 g / m 2 ^The average surface density of 250 g / m < ² > may not have sufficient mechanical properties such as strength and strength, and the average surface density may be 400 g / m < ² >, it is preferable to have a surface density within the above range because the improvement of the physical properties is insufficient as compared with the increase of the production cost caused by the increase of the surface density.

The melt-cellulose ultrafine nonwoven fabric of the present invention has an absorption coefficient of 0.85 or more at 1,000 Hz, which is a low-frequency logarithm, in the case of an average surface density of 300 g / m ² and an absorption coefficient measured according to an ISO cabinet method of ISO 354 , Preferably 0.86 to 0.95, and a sound absorption coefficient at 2,000 Hz of 0.95 or more, preferably 0.98 to 1.05. Further, the absorption coefficient may be 1.00 or more, preferably 1.02 to 1.10 at 3,150 Hz, and the absorption coefficient may be 1.08 or more, preferably 1.10 to 1.30 at a high frequency of 5,000 Hz.

The melt-cellulose ultrafine nonwoven fabric of the present invention can be applied to various known materials applied to the surface of the inner cover, such as nonwoven fabric, woven fabric, knitted fabric, foam, film, paper, spunbond fabric, , A staple web, or the like, may be used alone or in combination of two or more. Such a support covers the surface of the sound absorbing material applied to the interior of the vehicle or the inside of the building to maintain the shape of the sound absorbing material and to provide strength, and also prevents the fibers of the non-woven fabric from being detached as the seal passes, .

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

[ Example ]

Example  One

60% by weight of a cellulose acetate resin having a degree of substitution of cellulose hydroxyl group of 2.4, a weight average molecular weight of 30,000 (manufactured by Eastman) and 40% by weight of polyethylene glycol having a weight average molecular weight of 200 were mixed to prepare a mixture 1.

Next, 100 parts by weight of the mixture was mixed with tetrakis methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane (Anox 20 (Chemtura Corporation) (Alcanox 240, Camtura Corporation) as a radical activity inhibitor and then mixed for 2 minutes using a supermixer to prepare a mixture 2.

Next, the mixture 2 was dried in a hot air drier at 80 DEG C for 24 hours to be chips.

Next, using a kneader equipped with a twin extruder, the kneader was fixed at a kneader die (DIE) starting temperature of 170 ° C in five stages at a final terminal temperature of 200 ° C The chips were blended for 5 minutes while applying a temperature to prepare a molten cellulose acetate resin.

Next, the molten cellulose acetate resin was spin-coated at a die temperature of 250 DEG C and a hot air temperature of 260 DEG C in a meltblowing apparatus equipped with a nip with a width of 1960 mm and 35 HPI (Hole Per Inch) And a meltblown fiber aggregate having an average area density of 300 g / m ² composed of meltblown fibers was prepared. At this time, the meltblown fibers had an MI (Melt Index) of 156 g / 10 min (250 ° C) and an average diameter of the meltblown fibers of 4.8 μm.

Next, ultrasonic treatment was carried out by passing the meltblown fiber aggregate through the water tubs communicating with the lower three of the three upper parts equipped with the ultrasonic generator at a speed of 900 mpm for 20 seconds. At this time, the water temperature in the water bath was 60 ° C, The ultrasonic intensity in the water tank was 360 Hz.

Next, the fibers passed through the water tank were immersed in a 10% NaOH aqueous solution for 90 minutes in the saponification step, taken out, and dried using a hot air drier to prepare a molten cellulose ultrafine nonwoven fabric.

Experimental Example  One : SEM  Measure

A part of the microfibrillated cellulose microcellulose fabric prepared in Example 1 was cut out and the inside of the nonwoven fabric was measured with a scanning electron microscope (SEM, manufacturer JEOL, product name: JSM 840). The results are shown in FIG. 1 and FIG.

1 and 2, it can be confirmed that micropores are formed in the fibers constituting the nonwoven fabric, and the micropores have an average diameter of about 200 nm to 400 nm.

Example  2

58% by weight of a cellulose acetate resin having a weight average molecular weight of 28,000 (manufactured by Eastman) and a weight-average molecular weight of 200 and polyethylene glycol 42 having a weight average molecular weight of 200 %, And the mixture was used to prepare a nonwoven fabric having an average area density of 300 g / m ² . The average diameter of the meltblown fibers in the nonwoven fabric was 4.6 mu m.

Example  3

62% by weight of a cellulose acetate resin having a weight average molecular weight of 3,400 and a weight average molecular weight of 200 (polyethylene glycol 38) having a degree of substitution of cellulose hydroxyl group of 3.0 and a weight average molecular weight of 3,400 were produced under the same conditions and in the same manner as in Example 1 %, And the mixture was used to prepare a nonwoven fabric having an average area density of 300 g / m ² . The mean diameter of the meltblown fibers in the nonwoven fabric was 4.9 mu m.

Example  4

In Example 1, was prepared a nonwoven fabric under the same conditions and method wherein the cellulose acetate resin (East things, Ltd.) 52% by weight and producing a non-woven fabric having an average area density 300g / m ² using a mixture by mixing the polyethylene glycol 48% by weight Respectively. The mean diameter of the meltblown fibers in the nonwoven fabric was 4.5 mu m.

Example  5

A nonwoven fabric was produced under the same conditions and in the same manner as in Example 1 except that 60% by weight of a cellulose acetate resin having a degree of substitution of cellulose hydroxyl group of 2.4, a weight average molecular weight of 28,000 (manufactured by Eastman) and a weight average molecular weight of 180, polyethylene glycol 40 %, And the mixture was used to prepare a nonwoven fabric having an average area density of 300 g / m ² . The average diameter of the meltblown fibers in the nonwoven fabric was 4.6 mu m.

Example  6

A nonwoven fabric was produced by the same conditions and the same method as in Example 1 except that the melt-spun meltblown fiber aggregate was subjected to ultrasonic treatment at an ultrasonic intensity of 340 Hz to prepare a nonwoven fabric having an average area density of 300 g / m ² . The average diameter of the meltblown fibers in the nonwoven fabric was 4.7 mu m.

Comparative Example  One

A nonwoven fabric was produced in the same conditions and in the same manner as in Example 1 except that a polypropylene resin (HP 461Y from Polymira) was used in place of the cellulose acetate resin and a plasticizer was not used to produce a nonwoven fabric having an average area density of 300 g / m ² . The mean diameter of the meltblown fibers in the nonwoven fabric was 4.2 탆.

Comparative Example  2

Nonwoven fabrics were produced under the same conditions and in the same manner as in Example 1 except that triacetin instead of polyethylene glycol was used as a plasticizer as a plasticizer to prepare a nonwoven fabric having an average area density of 300 g / m ² . The mean diameter of the meltblown fibers in the nonwoven fabric was 5.3 탆.

Comparative Example  3

A nonwoven fabric was produced in the same conditions and in the same manner as in Example 1 except that the ultrasonic treatment was not performed, and a nonwoven fabric having an average area density of 300 g / m ² was produced. The average diameter of the meltblown fibers in the nonwoven fabric was 5.2 mu m.

Comparative Example  4

A nonwoven fabric was produced by the same conditions and procedures as in Example 1 except that a mixture of 80% by weight of the cellulose acetate resin and 20% by weight of the polyethylene glycol was used to prepare a nonwoven fabric having an average area density of 300 g / m ² . The mean diameter of the meltblown fibers in the nonwoven fabric was 5.8 mu m.

Comparative Example  5

A nonwoven fabric was produced using polyethylene glycol having a weight average molecular weight of 400 as a plasticizer instead of polyethylene glycol having a weight average molecular weight of 200 by the same conditions and procedures as in Example 1 to prepare a nonwoven fabric having an average surface area of 300 g / m ² . The average diameter of the meltblown fibers in the nonwoven fabric was 5.5 mu m.

Comparative Example  6

(2,4-di-t-butylphenyl) phosphite, which is the radical activity inhibitor, was added in an amount of 3.0 parts by weight per 100 parts by weight of the mixture to obtain an average area density of 300 g / m < ^{2 &} gt ;. The average diameter of the meltblown fibers in the nonwoven fabric was 4.4 mu m.

Comparative Example  7

A nonwoven fabric was produced by the same conditions and method as in Example 1 except that the melt-spun meltblown fibrous aggregate was subjected to ultrasonic treatment at an ultrasonic intensity of 270 Hz to produce a nonwoven fabric having an average area density of 300 g / m ² . The average diameter of the meltblown fibers in the nonwoven fabric was 4.8 mu m.

Experimental Example  : By frequency Hz ) Sound absorption coefficient measurement experiment

The sound absorption coefficient and adhesive strength (Hz) of the composite fiber assemblies prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1 below.

(1) Sound absorption coefficient measurement by frequency

For the measurement of the sound absorption coefficient, three samples each of which is applicable to the ISO R 354, Alpha Cabin method were prepared, and the sound absorption coefficient was measured after leaving for 30 minutes at the external temperature of 0 ° C and 25 ° C, and the average value of the measured sound absorption coefficient is shown in Table 1 .

(2) Remaining Amount of plasticizer  Measure

10 g of the sample was collected and stirred for 1 hour at 90 ° C in hot water, and then the weight of the dried sample was measured to determine the amount of residual residual in the nonwoven fabric.

division Sound absorption coefficient by frequency Nonwoven fabric
Remaining plasticizer amount
(weight%) Average diameter (占 퐉) of meltblown fibers in the nonwoven fabric Of the meltblown fibers in the nonwoven fabric
MI
(g / 10 min, 250 < 0 > C) 1,000 Hz 2,000 Hz 3,150 Hz 5,000 Hz Example 1 0.86 0.98 1.05 1.14 0 4.8 156 Example 2 0.87 0.98 1.08 1.16 0 4.6 152 Example 3 0.86 0.97 1.04 1.11 0 4.9 159 Example 4 0.86 0.97 1.03 1.12 0 4.5 156 Example 5 0.88 0.99 1.09 1.18 0 4.6 153 Example 6 0.86 0.97 1.05 1.13 0 4.7 157 Comparative Example 1 0.85 0.92 0.96 1.02 0 4.2 167 Comparative Example 2 0.82 0.91 0.95 1.07 4 5.3 158 Comparative Example 3 0.81 0.87 0.91 1.01 28 5.2 138 Comparative Example 4 0.78 0.85 0.89 0.99 0 5.8 160 Comparative Example 5 0.79 0.87 0.92 1.02 2 5.5 147 Comparative Example 6 0.80 0.92 0.98 1.05 0 4.4 150 Comparative Example 7 0.82 0.94 1.00 1.06 One 5.0 158

The results of Table 1 show that Examples 1 to 6 of the present invention have excellent sound absorbing characteristics as a whole, and the remaining amount of the plasticizer in the nonwoven fabric is insufficient or not present.

However, in Comparative Example 1 in which a nonwoven fabric was produced using polypropylene, the low sound absorption characteristics were low as compared with Example 1, which is judged to be a result of the difference in the composition of the fibers themselves and the porosity of the fibers.

In the case of Comparative Example 2 using triacetin as a plasticizer, the plasticizer remained in a large amount of nonwoven fabric despite the ultrasonic treatment under the same conditions, and there was a problem that the sound absorption property was poor as compared with Example 1.

In Comparative Example 3, the amount of the plasticizer in the nonwoven fabric was large. Compared with Example 1, however, the sound absorbing property was poor, and the range of the applied product greatly decreased due to the presence of the plasticizer in the nonwoven fabric.

In the case of Comparative Example 4 in which the plasticizer content was less than 25% by weight, the plasticizing effect deteriorated and the formation of pores in the meltblown fibers of the nonwoven fabric was not achieved well, and the average diameter of the meltblown fibers . As a result, it was judged that the specific surface area was smaller than that of the fiber in the nonwoven fabric of Example 1, which adversely affected the sound absorption properties.

Further, in the case of Comparative Example 5 using polyethylene glycol having a weight average molecular weight of more than 350, the plasticizer did not elute well and remained in the nonwoven fabric. The average diameter of the meltblown fibers was larger than that of Example 1, And the specific surface area is decreased, which is considered to be the result that the sound absorption property is lowered.

In Comparative Example 6 in which the radical activity inhibitor was used in an amount exceeding 2.5 parts by weight based on 100 parts by weight of the mixture, the average diameter of the meltblown fibers in the nonwoven fabric was greatly reduced as compared with Example 1, It is judged that the cellulose ester resin melted in the thermoplastic or melt spinning process is pyrolyzed.

Also, in the case of Comparative Example 7 in which the plasticizer elution process was performed with an ultrasonic wave of 270 Hz intensity at an ultrasonic frequency of less than 300 Hz, there was a problem that the plasticizer in the nonwoven fabric remained, resulting in poor sound absorption.

It can be seen from the above Examples and Experimental Examples that the melt-cellulose ultrafine nonwoven fabric of the present invention has an excellent sound absorbing ability not only in a high frequency band but also in a low frequency band. The present invention can be applied to a material requiring sound absorption, for example, an interior part of a moving means such as an automobile, an airplane, a ship, an electronic product part such as a cell phone, a notebook computer, a TV, It is expected. Further, it is expected that the fibers in the melt-cellulose ultrafine nonwoven fabric of the present invention having pores and having an excellent specific surface area can be used as filter media, cosmetic mask sheets and the like.

Claims (20)

0.01 to 2 parts by weight of a radical generation inhibitor and 0.001 to 2.5 parts by weight of a radical activity inhibitor based on 100 parts by weight of a mixture comprising 50 to 70% by weight of a thermoplastic cellulose ester resin and 30 to 50% by weight of a plasticizer,
The thermoplastic cellulose ester resin preferably has a cellulose hydroxyl group substitution degree of 1.7 to 3.0, a weight average molecular weight of 20,000 to 32,000,
The plasticizer includes at least one selected from polyethylene glycol, polypropylene glycol, polyglycolic acid and polybutyl adipate having a weight average molecular weight of 100 to 250,
Wherein the radical generation inhibitor comprises a water insoluble compound including a phenol group, and the radical activity inhibitor comprises a water insoluble compound containing phosphorus at the terminal. The melted cellulose type meltblown fiber composition for a sound absorbing material nonwoven fabric according to claim 1,
delete The thermoplastic resin composition according to claim 1, wherein the thermoplastic cellulose ester resin
Selected from cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose acetate caprate, cellulose acetate caprylate, cellulose acetate laurethate, cellulose acetate palmitate, cellulose acetate stearate and cellulose acetate oleate Wherein the meltblown cellulose-based meltblown fiber composition for a sound-absorbing material nonwoven fabric comprises at least one member selected from the group consisting of polyvinyl alcohol and polyvinyl alcohol.
delete delete The method of claim 1, wherein the radical generation inhibitor is selected from the group consisting of tetrakis methylene (3,5-di-t-butyl-4-hydroxycinnamate) methane, pentaerythritol tetrakis (3- (3,5- Butyl-4-hydroxyphenyl) propionate and tetrakis methylene (3,5-di-t-butyl-4-hydroxyphenyl) propionate methane. Meltblown cellulose based meltblown fiber composition for nonwoven fabrics.
The sound absorbing material according to claim 1, wherein the radical activity inhibitor comprises at least one selected from tris (2,4-di-t-butylphenyl) phosphite and tris-nonylphenyl phosphite and triphenyl phosphite Meltblown cellulose based meltblown fiber composition for nonwoven fabrics.
The melted cellulose-based meltblown fiber composition for a sound absorbing material nonwoven fabric according to claim 1, further comprising 0.05 to 2.5 parts by weight of a carbodiimide-based hydrolysis inhibitor per 100 parts by weight of the mixture.
And melt-cellulose ester-based meltblown fibers having an MI (melt index) of 140 to 170 g / 10 min (250 ° C) and an average diameter of 2.5 to 5 μm, wherein the meltblown fibers have an average particle diameter of 100 nm to 600 nm And a plurality of micropores having a plurality of micropores,
Wherein the plasticizer content in the total weight of the nonwoven fabric is 0.2 wt%
When the average surface area density is 300 g / m ² , the sound absorption coefficient is measured to be 0.85 or more at 1,000 Hz, the sound absorption coefficient is at least 0.95 at 2,000 Hz, and 3,150 And a sound absorption coefficient of 1.08 or more at 5,000 Hz, and a sound absorption coefficient of 1.08 or more at 5,000 Hz.
The microcellular nonwoven fabric according to claim 9, wherein the total weight of the nonwoven fabric is 0.01 to 0.2% by weight of a plasticizer.
delete delete delete delete Mixing the melted cellulose-based meltblown fiber composition for a sound absorbing material nonwoven fabric according to any one of claims 1, 3, and 6 to produce a mixed resin;
Drying the mixed resin at 70 ° C to 90 ° C for 20 to 30 hours to prepare a thermoplastic cellulose ester chip;
Adding the thermoplastic cellulose ester chip to a kneader and blending the kneaded mixture under a condition of raising the internal temperature of the kneader from 150 ° C to 220 ° C to prepare a melted cellulose ester resin;
Preparing a meltblown fiber aggregate by melt-spinning the molten cellulose ester resin through a meltblown die and a nip while simultaneously using hot air at a high temperature and a high pressure; And
Immersing the meltblown fibrous aggregate in water and sonicating to elute the plasticizer;
Immersing the meltblown fibrous aggregate from which the plasticizer has been eluted in an aqueous solution of NaOH at a concentration of 5 to 15 vol% for 60 to 120 minutes, And
Drying the saponified meltblown fibrous aggregate;
The method of manufacturing a microcellular nonwoven fabric of molten cellulose for a sound absorbing material according to claim 1,
The method of claim 15, wherein the melt spinning is performed at a hot air temperature of 260 ° C to 290 ° C.
16. The method of claim 15, wherein the temperature of water in the step of eluting the plasticizer is from 50 to 70 DEG C, and the ultrasound intensity is 300 to 400 Hz during ultrasonic treatment.
A sound absorbing material comprising the melt-cellulose ultrafine nonwoven fabric of claim 9 or 10. delete delete

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