CN114901882B

CN114901882B - Fiber aggregate for automobile interior material and automobile interior material comprising same

Info

Publication number: CN114901882B
Application number: CN202080090307.9A
Authority: CN
Inventors: 韩松贞; 李主铉; 金棹炫
Original assignee: Korea Shangdongli Advanced Materials Co ltd
Current assignee: Korea Shangdongli Advanced Materials Co ltd
Priority date: 2019-12-27
Filing date: 2020-12-24
Publication date: 2023-09-08
Anticipated expiration: 2040-12-24
Also published as: JP2023508484A; WO2021133116A1; JP7419540B2; CN114901882A

Abstract

The present invention relates to a fiber assembly for an automotive interior material, and more particularly, to a fiber assembly for an automotive interior material, which has excellent touch, sound absorption coefficient, adhesive strength, and processability, minimizes aged deterioration due to excellent heat resistance, and remarkably reduces emission of Volatile Organic Compounds (VOCs), thereby being particularly suitable for realizing a closed environment, and an automotive interior material including the same.

Description

Fiber aggregate for automobile interior material and automobile interior material comprising same

Technical Field

The present invention relates to a fiber assembly for an automotive interior material, and more particularly, to a fiber assembly for an automotive interior material, which has excellent touch, sound absorption coefficient, adhesive strength, modulus of resilience, and processability, minimizes aged deterioration due to excellent heat resistance, and remarkably reduces emission of Volatile Organic Compounds (VOCs), thereby being particularly suitable for realizing a closed environment of an automobile, and an automotive interior material comprising the same.

Background

In general, synthetic fibers often have limited uses due to their high melting points. In particular, in the application of bonding of fibers or the like, when used as a core or the like or as an adhesive to be interposed between belt-like fabrics for pressure bonding, there is a possibility that the fiber fabrics themselves are deteriorated by heating, and there is a problem that special equipment such as a high-frequency sewing machine can be used only, and therefore it is expected that bonding can be easily performed by a general simple hot press without using such special equipment.

In the case of conventional low-melting polyester fibers used for producing mattresses, interior materials for automobiles, and various nonwoven fabric fillers, hot Melt (Hot Melt) binder fibers are widely used for bonding different types of fibers to common fiber structures used.

For example, in U.S. patent No. 4,129,675, a low-melting polyester is described using terephthalic acid (terephthalic acid: TPA) and isophthalic acid (IPA), and korean patent No. 10-1216690 discloses a low-melting polyester fiber containing isophthalic acid and diethylene glycol to improve adhesion.

However, the conventional low-melting polyester fiber may have a spinning property and an adhesive property at a certain level or more, but has a problem in that it gives a hard feel to an automotive interior material after thermal bonding due to the ring-shaped structure of the rigidity modifier.

In addition, as development is conducted toward a polyester having a low melting point or a low glass transition temperature in order to exhibit adhesive properties, the heat resistance of the polyester to be achieved is poor, a change with time is remarkably generated even under a storage condition exceeding 40 ℃ in summer, and a problem of remarkably reduced storage stability due to the occurrence of bonding between polyester fibers during storage. In particular, when a polyester fiber having poor heat resistance is used under the above conditions, the temperature in the interior of an automobile, which is stopped outdoors in summer, increases to 60 ℃ or higher, and the time-dependent change of the interior material is also problematic.

On the other hand, automobiles generally travel in a state of being isolated from the outside, and in particular, recently, there is a tendency to travel in a more closed state due to the influence of dust or the like. Therefore, the air quality of the interior space of the automobile is important, and it is reported that a problem of emission of Volatile Organic Compounds (VOCs) in interior materials mounted in the interior space occurs, and a problem of harming the health of passengers due to the emitted volatile organic compounds is beginning to rise.

Therefore, there is an urgent need to develop an automotive interior material capable of improving the touch feeling, sound absorption coefficient, adhesive strength, modulus of resilience, and processability, minimizing the change with time, and remarkably reducing the emission of volatile organic compounds.

Disclosure of Invention

Technical problem

The present invention has been made in view of the above-described problems, and an object thereof is to provide a fiber aggregate for an automotive interior material, which has excellent touch feeling, sound absorption coefficient, adhesive strength, modulus of elasticity, and workability, minimizes aged deterioration due to excellent heat resistance, and remarkably reduces emission of volatile organic compounds, and is thus particularly suitable for realizing a closed environment, and an automotive interior material comprising the same.

Solution to the problem

In order to solve the above problems, the present invention provides a fiber aggregate for an automotive interior material, comprising: a heat-bondable fiber comprising a copolyester obtained by polycondensation of an esterified compound obtained by reacting an acid component comprising terephthalic acid with a diol component comprising ethylene glycol, a compound represented by the following chemical formula 1 and a compound represented by the chemical formula 2; and polyester-based support fibers having a melting point of greater than 250 ℃, the weight ratio of the thermally bondable fibers to the support fibers being from 20:80 to 50:50.

[ chemical formula 1]

[ chemical formula 2]

According to an embodiment of the present invention, the total content of the compound represented by chemical formula 1 and the compound represented by chemical formula 2 may be 30 to 45 mole% of the diol component.

In addition, in the above diol component, the content (mol%) of the compound represented by chemical formula 1 may be greater than the content (mol%) of the compound represented by chemical formula 2.

Further, the glycol component may not include substantially diethylene glycol.

In addition, the above acid component may further include 1 to 10 mol% of isophthalic acid based on the acid component.

In addition, the diol component may include 1 to 40 mol% of the compound represented by the above chemical formula 1 and 0.8 to 20 mol% of the compound represented by the above chemical formula 2, more preferably, 20 to 40 mol% of the compound represented by the above chemical formula 1 and 0.8 to 10 mol% of the compound represented by the above chemical formula 2, and still more preferably, 30 to 40 mol% of the compound represented by the above chemical formula 1 and 0.8 to 6 mol% of the compound represented by the above chemical formula 2.

Further, the glass transition temperature of the above-mentioned copolyester may be 60℃to 75℃and more preferably 65℃to 72 ℃.

In addition, the above-mentioned copolyester may have an intrinsic viscosity of 0.500dl/g to 0.800 dl/g.

Further, the weight ratio of the above-mentioned heat-bondable fibers to the supporting fibers may be 30:70 to 40:60.

Further, in the frequency range of 400Hz to 2000Hz, the average sound absorption coefficient may be 0.35 or more.

Further, as the sound absorption coefficient according to KS F2805, (1) at a frequency of 1000Hz, the sound absorption coefficient may be 0.53 or more; (2) At 2000Hz, the sound absorption coefficient may be 0.73 or more; (3) At 3000Hz, the sound absorption coefficient may be 0.83 or more; (4) At 4000Hz the sound absorption coefficient may be above 0.92.

Further, the amount of volatile organic compound discharged from the heat-bondable fiber as measured by the U.S. EPA TO-14 method may be 2600ppb or less, and more preferably 2200ppb or less.

Further, the adhesive strength according to KS M ISO 36 may be 130N/25 mm to 200N/25 mm.

Further, the modulus of resilience may be 45% to 60%.

The present invention also provides an automotive interior material comprising the fiber aggregate for an automotive interior material according to the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

The fiber aggregate for an automotive interior material according to the present invention is excellent in touch, sound absorption coefficient, adhesive strength, modulus of resilience, and processability. Further, since the heat resistance is excellent, the change with time can be minimized, and the heat resistance is very suitable for use as an automotive interior material having a high indoor temperature when the vehicle is parked outdoors in summer. In addition, since the emission amount of the volatile organic compounds is remarkably reduced, the material is very suitable for automotive interior materials which are increased in running in a closed environment, and can be widely applied to the related fields.

Drawings

Fig. 1 is a cross-sectional view of a thermobondable fiber included in an embodiment of the present invention.

Detailed Description

Best mode for carrying out the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so as to enable those skilled in the art to which the present invention pertains to easily implement the present invention. The invention may be realized in many different embodiments and is not limited to the examples described in this specification.

The fiber aggregate for an automotive interior material according to the present invention is realized by comprising a heat-bondable fiber comprising a copolyester obtained by polycondensation reaction of an esterified compound obtained by reaction of an acid component comprising terephthalic acid and a glycol component comprising ethylene glycol, a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2, and a polyester-based support fiber having a melting point higher than 250% in a weight ratio of 20:80 to 50:50.

The heat-bondable fibers are fibers comprising a copolyester obtained by polycondensation of an esterified compound obtained by reacting an acid component containing terephthalic acid with a glycol component containing ethylene glycol, a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2, and serve to adhere polyester-based support fibers, which will be described below, by heat welding, and are fibers that themselves ensure the shape realization and mechanical strength of the fiber assembly.

[ chemical formula 1]

[ chemical formula 2]

First, the above acid component includes terephthalic acid, and may include an aromatic polycarboxylic acid having 6 to 14 carbon atoms or an aliphatic polycarboxylic acid having 2 to 14 carbon atoms and/or a sulfonic acid metal salt in addition to terephthalic acid.

As the above aromatic polycarboxylic acid having 6 to 14 carbon atoms, a known one as an acid component for producing a polyester may be used without limitation, and preferably at least one selected from the group consisting of dimethyl terephthalate, isophthalic acid and dimethyl isophthalate, and more preferably isophthalic acid may be used in view of reaction stability with terephthalic acid, ease of handling and economy.

Further, as the aliphatic polycarboxylic acid having 2 to 14 carbon atoms, a substance known as an acid component for producing a polyester may be used without limitation, and as a non-limiting example thereof, at least one selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, citric acid, pimelic acid, azelaic acid, sebacic acid, nonanoic acid, decanoic acid, dodecanoic acid and hexadecanoic acid may be used.

Further, the metal sulfonate may be sodium 3, 5-dimethoxybenzenesulfonate.

On the other hand, the acid component may be contained in addition to terephthalic acid, and is preferably not contained because other components may lower the heat resistance of the copolyester. In particular, when further containing an acid component such as isophthalic acid or dimethyl isophthalate, the content of volatile organic compounds such as acetaldehyde generated during polycondensation of the copolyester may be increased, and the melting point of the copolyester is further lowered, so that it is difficult to remove the acetaldehyde generated during polymerization by vaporization through a subsequent process such as heat treatment, and as a result, the resulting fiber may have a high content of acetaldehyde. In the case of further including isophthalic acid, the content of the above isophthalic acid may be 1 to 10 mole% based on the acid component, and when the content of the above isophthalic acid is more than 10 mole%, the content of acetaldehyde may be excessively increased, whereby the heat-bondable fiber achieved may not be suitable for automotive interior material use.

Next, the diol component includes ethylene glycol, a compound represented by the following chemical formula 1, and a compound represented by the following chemical formula 2.

[ chemical formula 1]

[ chemical formula 2]

First, the compound represented by the above chemical formula 1 may reduce crystallinity and glass transition temperature of the prepared copolyester to help to exhibit excellent thermal bonding properties. In addition, after being prepared into a fiber shape, the dyeing process can be performed under normal pressure in the dyeing process, so that the dyeing process is easier, and the washing fastness can be improved and the touch feeling of the fiber assembly can be improved due to the excellent dyeing characteristic. Preferably, the diol component may include 20 to 40 mole% of the compound represented by the above chemical formula 1, and more preferably, 30 to 40 mole% of the compound represented by the above chemical formula 1. In particular, if the compound represented by chemical formula 1 is included at 20 mol% or more, the heat-bonding property at low temperature of the copolyester realized together with the compound represented by chemical formula 2 to be described below can be further improved, the drying time can be remarkably shortened when the copolyester is formed into a chip, and there is an advantage in that a synergistic effect can be exerted in terms of the reduction in the content of volatile organic compounds released from the heat-bonding fibers.

If the compound represented by chemical formula 1 is included in an amount of less than 20 mole% based on the diol component, although spinning property is excellent, there is an increase in hot-tack temperature or a decrease in hot-tack property, and the use application may be limited. Furthermore, the content of volatile organic compounds released from the realized heat-bondable fibers may be increased. If the content of the compound represented by chemical formula 1 is more than 40 mol%, the spinnability as a heat-bondable fiber is poor, which may cause a problem that commercialization is difficult, and the crystallinity is increased, which may deteriorate the heat-bondability.

The compound represented by the above chemical formula 2 further improves the heat adhesion property of the produced copolyester together with the compound represented by the above chemical formula 1, and also prevents the glass transition temperature of the compound represented by the chemical formula 1 from being significantly lowered, thereby minimizing the change with time even under the storage condition of 40 ℃ or more or the temperature in the automobile room rising to 60 ℃ or more in summer, and enabling the improvement of the storage stability. Regarding the heat adhesiveness, the compound represented by chemical formula 2 and the compound represented by chemical formula 1 are used in combination, so that the heat-adhesiveness fiber using the copolyester achieved exhibits an appropriate shrinkage characteristic, by which the point adhesion force is further increased at the time of heat bonding, and thus further improved heat bonding characteristics can be exhibited.

Preferably, the content of the compound represented by the above chemical formula 2 in the above diol component may be 0.8 to 10 mol%, more preferably, may be 0.8 to 6 mol%.

If the compound represented by chemical formula 2 is included in an amount of less than 0.8 mol% based on the diol component, it is difficult to achieve the intended improvement in heat resistance, and thus the storage stability is poor and the change with time may be large. Furthermore, the content of volatile organic compounds released from the realized heat-bondable fibers may be increased.

If the content of the compound represented by chemical formula 2 is more than 10 mol%, the problem that the use of the compound represented by chemical formula 1 together with the compound is difficult to commercialize may occur because the spinning property as a heat-bondable fiber is poor, and if isophthalic acid is further included, the improvement in the adhesiveness is small because the crystallinity is sufficiently reduced, and the crystallinity is rather increased when the content of isophthalic acid to be added is increased, and thus the object of the present invention may not be achieved, for example, excellent heat-bonding characteristics may be significantly reduced at an intended temperature. In addition, when it is realized in a fibrous form, shrinkage is remarkably exhibited, and thus it is difficult to process it into a fiber aggregate or an interior material.

According to a preferred embodiment of the present invention, the total content of the compound represented by chemical formula 1 and the compound represented by chemical formula 2 is preferably 30 to 45 mol%, more preferably 33 to 41 mol% in the diol component. If the total content is less than 30 mol%, crystallinity of the copolyester is increased, and thus a high melting point is exhibited or a softening point is hardly achieved at a low temperature, so that a hot tack temperature is remarkably increased, and an excellent hot tack property cannot be exhibited at a low temperature. Furthermore, the content of volatile organic compounds released from the realized heat-bondable fibers may be increased.

In addition, if the content of the compound represented by chemical formula 2 is more than 45 mol%, there is a possibility that the polymerization reactivity and spinning property are significantly reduced, and the crystallinity of the produced copolyester is rather improved, so that it may be difficult to exhibit high thermal adhesion characteristics at a desired temperature.

At this time, the content (mol%) of the compound represented by the above chemical formula 1 may be greater than the content of the compound represented by the chemical formula 2 in the above diol component. If the content of the compound represented by chemical formula 1 is less than or equal to the content of the compound represented by chemical formula 2, it is difficult to exhibit the intended thermal adhesion characteristics, and since thermal adhesion is only possible at high temperature, the use of the product to be developed is limited. Furthermore, it may be difficult to process the product to be developed due to the manifestation of excessive shrinkage characteristics.

On the other hand, the above glycol component may further include other types of glycol components in addition to the compound represented by the above chemical formula 1, the compound represented by the chemical formula 2, and ethylene glycol.

The present invention is not particularly limited as to this since the above-mentioned other types of glycol components may be well known glycol components for producing polyesters, but as non-limiting examples thereof, the above-mentioned other types of glycol components may be aliphatic glycol components having 2 to 14 carbon atoms, specifically, at least one selected from the group consisting of 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, propanediol, trimethylglycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, undecamethylene glycol, dodecamethylene glycol, and tridecylethylene glycol.

However, in order to have heat resistance in combination with a desired level of thermal adhesion characteristics, it is preferable that the other types of glycol components are not contained, and in particular, the glycol components may not contain diethylene glycol. If the glycol component contains diethylene glycol, a rapid decrease in glass transition temperature occurs, and therefore, even if the compound represented by chemical formula 2 is contained, the desired level of heat resistance may not be achieved. Furthermore, there is a possibility that the content of volatile organic compounds released in use may increase. On the other hand, the absence of diethylene glycol in the diol component means that diethylene glycol is not intentionally added as a monomer in the production of the copolyester, but diethylene glycol which is produced as a by-product in the esterification reaction or polycondensation reaction of the acidic component and the diol component is not included. Since diethylene glycol may naturally occur as a byproduct, according to an embodiment of the present invention, the sheath portion including the copolyester may further include diethylene glycol generated as a byproduct, and the content of diethylene glycol may be less than 4 wt% based on the weight of the copolyester chips or the sheath portion formed by the copolyester alone. On the other hand, if the content of diethylene glycol produced as a by-product exceeds an appropriate level, the holding pressure is increased at the time of spinning into fibers, and yarn breakage is frequently initiated, so that the spinnability is significantly reduced, and the content of volatile organic compounds discharged, particularly the amount of acetaldehyde discharged, may be significantly increased.

The acid component and the diol component may be prepared into a copolyester through an esterification reaction and a polycondensation reaction using synthesis conditions well known in the art of polyester synthesis. At this time, the acid component and the glycol component may be charged in a molar ratio of 1:1.0 to 1:5.0, preferably in a molar ratio of 1:1.0 to 1:2.0, to carry out the reaction, but are not limited thereto.

On the other hand, the acid component and the diol component may be mixed at a time in the above-mentioned proper molar ratio and then subjected to an esterification reaction and a polycondensation to prepare a copolyester, or the compound represented by chemical formula 2 may be added to an esterification reaction between ethylene glycol in the acid component and the diol component and a compound represented by chemical formula 1, and then subjected to an esterification reaction and a polycondensation reaction to prepare a copolyester, which is not particularly limited in the present invention.

A catalyst may be further included in the esterification reaction. The above catalyst may be used as a catalyst generally used in the preparation of polyesters, and as a non-limiting example thereof, may be prepared under the catalysis of a metal cellulose catalyst.

In addition, the esterification reaction may be carried out at a temperature of 200℃to 270℃and a pressure of 1100 Torr to 1350 Torr. If the above conditions are not satisfied, there is a problem in that the esterification reaction time is prolonged or an esterified compound suitable for polycondensation reaction cannot be formed due to a decrease in reactivity.

In addition, the polycondensation reaction may be carried out at a temperature of 250 to 300℃and a pressure of 0.3 to 1.0 Torr, and if the above conditions are not satisfied, there may be problems such as a delay in reaction time, a decrease in polymerization degree, and initiation of thermal decomposition.

In this case, a catalyst may be further included in the polycondensation reaction. The catalyst is not limited as long as it is a known catalyst for producing a polyester resin. However, the above catalyst may be preferably a titanium-based polymerization catalyst, and more specifically, may be a titanium-based polymerization catalyst represented by the following chemical formula 3.

[ chemical formula 3]

The titanium-based polymerization catalyst represented by the above chemical formula 3 is stable in the presence of water molecules, and therefore, even if the titanium-based polymerization catalyst is added before the esterification reaction by-producing a large amount of water, it is not deactivated, and thus, the esterification reaction and the polycondensation reaction can be performed in a shorter time than before, whereby coloring due to yellowing can be suppressed. The content of the above catalyst may be 5ppm to 40ppm in terms of titanium atom based on the total weight of the finally obtained copolyester, whereby the heat stability or color tone of the copolyester becomes more excellent, and thus is preferable. If the content of the catalyst is less than 5ppm in terms of titanium atoms, it is difficult to properly promote the esterification reaction, and if the content of the catalyst is more than 40ppm in terms of titanium atoms, the reactivity can be promoted, but a coloring problem occurs.

On the other hand, a heat stabilizer may be further included in the polycondensation reaction. The heat stabilizer is a phosphorus compound for preventing discoloration due to thermal decomposition at high temperature. As the phosphorus compound, phosphoric acids such as phosphoric acid, monomethyl phosphoric acid, trimethyl phosphoric acid, tributyl phosphoric acid and derivatives thereof are preferably used, and among them, trimethyl phosphonic acid or triethyl phosphoric acid is more preferable because of excellent effect. The amount of the above-mentioned phosphorus compound to be used may be 10ppm to 30ppm in terms of phosphorus atom based on the total weight of the finally obtained copolyester. If the amount of the phosphorus-based heat stabilizer is less than 10ppm, it is difficult to prevent high-temperature pyrolysis, and thus discoloration of the copolyester is caused, and if the amount of the phosphorus-based heat stabilizer is more than 30ppm, it is disadvantageous in terms of production cost, and there is a possibility that a reaction delay phenomenon occurs due to the inhibition of catalytic activity by the heat stabilizer during the polycondensation reaction.

In addition, the copolyester may further include a complementary colorant. The complementary color agent is a color tone process for making the color of a dye dyed in a dyeing process performed after spinning the fiber thicker and better, and a complementary color agent known in the fiber field may be added, and as a non-limiting example thereof, a dye for stock dyeing, a pigment, a vat dye, a disperse dye, an organic pigment, and the like may be cited. Preferably, however, a mixture of blue and red dyes may be used. This is because cobalt compounds, which are generally used as complementary colorants, are not preferred because they are harmful to the human body, but in contrast, complementary colorants of a mixture of blue and red dyes are not harmful to the human body and are therefore preferred. In addition, when a mixture of blue and red dyes is used, there is an advantage in that the hue can be finely controlled. The blue dye may include, for example, solvent blue 104, solvent blue 122, solvent blue 45, etc., and the red dye may include, for example, solvent red 111, solvent red 179, solvent red 195, etc. In addition, the blue dye and the red dye may be 1:1.0 to 1:3.0, thereby advantageously exhibiting a remarkable effect in the desired fine tone control.

The content of the complementary color agent may be 1ppm to 10ppm based on the total weight of the copolyester, and if the content of the complementary color agent is less than 1ppm, it may be difficult to achieve a desired level of complementary color characteristics, and if the content of the complementary color agent is more than 10ppm, the L value is lowered, so that there may be a problem in that transparency is lowered and a dark color is displayed.

The intrinsic viscosity of the copolyester according to the invention prepared by the above-described method may be 0.5dl/g to 0.8dl/g. If the intrinsic viscosity is less than 0.5dl/g, there may be a problem that a cross section is not easily formed, and if the intrinsic viscosity is more than 0.8dl/g, the spinning property may be lowered due to an excessively high holding pressure (pack).

In addition, the glass transition temperature of the above-mentioned copolyester may be 60℃to 75 ℃. Whereby the object of the invention can be more advantageously achieved. If the glass transition temperature is lower than 60 ℃, the thermal adhesive fiber comprising the copolyester or the article comprising the same may undergo a large change with time in an environment such as summer, for example, a temperature exceeding 40 ℃, and particularly, the change with time may be significantly increased in consideration of the indoor temperature of an automobile in summer. In addition, in the preparation of heat-bondable fibers, the bonding between the copolyester chips increases, which may lead to spinning defects. Further, when the fiber is formed into a fiber, the shrinkage property is excessively exhibited, which in turn reduces the thermal bonding property. Further, there may be a problem in that the time required for the process is prolonged or the related process cannot be smoothly performed due to limitations of heat treatment required for a drying process after forming the chips, post-processing after spinning the fibers, and the like.

In addition, if the glass transition temperature is greater than 75 ℃, the thermal bonding characteristics may be significantly reduced, and the execution temperature of the bonding process may be limited to high temperature.

The above-mentioned copolyesters can be formed alone into heat-bondable fibers. Alternatively, as shown in fig. 1, the above-mentioned copolyester is provided as a sheath portion 12 surrounding the core portion 11, whereby the core-sheath type heat-bondable fiber 10 can be formed.

In this case, the core 11 may be a known polyester having heat resistance and mechanical strength greater than those of the copolyester serving as the sheath, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, and polypropylene terephthalate. The core-sheath type heat-bondable fiber may be produced by, for example, composite spinning the core and the sheath at a weight ratio of 8:2 to 2:8, but the fiber is not limited thereto, and the ratio may be appropriately adjusted according to the purpose. The spinning conditions, spinning equipment, and processes such as cooling and drawing of the spun composite fiber may be performed under conditions, equipment, and processes known in the art, or after being appropriately deformed, and the present invention is not particularly limited thereto. The composite fiber can be spun at a spinning temperature of 270 to 290 ℃ and can be drawn 2.5 to 4.0 times after spinning, for example.

On the other hand, the fineness of the above-mentioned heat-bondable fibers may be 1 to 15 deniers, and the fiber length may be, for example, 1 to 100mm, but is not limited thereto.

Further, the heat-bondable fiber has a volatile organic compound generation amount of 2600ppb or less, more preferably 2200ppb or less according TO the U.S. EPA TO-14 method, and thus has an advantage that the amount of components harmful TO the human body in a closed environment such as an automobile interior is remarkably reduced, and thus it is very useful as an automobile interior material and the odor of the interior material can be reduced.

Next, the supporting fibers contained in the fiber aggregate together with the above-described heat-bondable fibers will be described.

The support fiber is realized by including a polyester component for compatibility with the heat-bondable fiber, and functions to secure mechanical strength, shape retention, and heat resistance of the fiber aggregate. For this reason, the above polyester-based component may be a component having a melting point higher than 250 ℃, whereby the object of the present invention may be more advantageously achieved.

The fineness of the support fiber may be, for example, 1 to 10 deniers, and the fiber length may be, for example, 1 to 100mm, but is not limited thereto.

The support fiber may be any known polyester component having a melting point of more than 250 ℃, and may be used without limitation, for example, polyethylene terephthalate.

The above-mentioned heat-bondable fibers and supporting fibers form a fiber aggregate in a weight ratio of 20:80 to 50:50, and preferably the weight ratio of the above-mentioned heat-bondable fibers and supporting fibers may be 30:70 to 40:60. If the supporting fibers are included in an amount of more than 4 times the weight of the heat-bondable fibers, there is a problem in that the adhesive strength of the fiber aggregate is lowered and the adhesive properties cannot be sufficiently exhibited. When the weight of the supporting fiber is less than one time the weight of the heat-bondable fiber, the sound absorption coefficient, touch feeling and shape stability of the fiber aggregate are remarkably reduced, workability such as initial cotton opening property and comb property are remarkably reduced, commercialization is difficult due to poor spinning property, and a nonwoven fabric or fabric having a hard feel after heat-bonding may be realized due to the loop structure of the rigidity modifier.

The fiber aggregate including the heat-bondable fibers and the support fibers may have a known cloth form, and may be, for example, a woven fabric, a knitted fabric, or a nonwoven fabric, and may be, for example, a nonwoven fabric that does not have directionality based on the fiber length direction. The nonwoven fabric may be produced by a known nonwoven fabric production method, which is either dry or wet, but the present invention is not particularly limited thereto.

For example, the heat-bondable fibers and the support fibers may be produced into short fibers having a predetermined length, and then subjected to fiber mixing and opening, and then subjected to heat treatment to produce a fiber aggregate. The above heat treatment temperature may be 100 to 180 ℃, preferably 120 to 180 ℃, and thus may exhibit more improved adhesive properties.

The fiber aggregate for an automotive interior material according to an embodiment of the present invention may have a sound absorption coefficient of 0.35 or more in a frequency range of 400Hz to 2000Hz as measured according to KS F2805. In addition, as the condition (1), the sound absorption coefficient at a frequency of 1000Hz may be 0.53 or more, more preferably, may be 0.53 to 0.75. In addition, as the condition (2), the sound absorption coefficient at a frequency of 2000Hz may be 0.73 or more, more preferably, may be 0.73 to 0.85. In addition, as the condition (3), the sound absorption coefficient at a frequency of 3000Hz may be 0.83 or more, more preferably, may be 0.83 to 0.95, and as the condition (4), the sound absorption coefficient at a frequency of 4000Hz may be 0.92 or more, more preferably, may be 0.92 to 0.99. Thus, a uniform and high sound absorption coefficient is satisfied in a wide frequency band, and thus, when used as an interior material for an automobile, noise outside the automobile and noise generated in the automobile itself can be prevented from being transmitted into a room.

Further, the adhesive strength according to KS M ISO 36 of the fiber aggregate for automotive interior material according to an embodiment of the present invention may satisfy 130N/25mm to 200N/25mm, more preferably, 140N/25mm to 200N/25mm. Since the fiber aggregate satisfying the above adhesive strength exhibits excellent mechanical strength, the adhesive property is advantageous even at the same processing temperature, and thus molding can be easily performed at the time of processing. In addition, the modulus of resilience may be 45% to 60%, and thus is more suitable for interior materials for automobiles, especially floor carpets.

On the other hand, the fiber aggregate for an automobile interior material may be realized as an automobile interior material alone or by further including regenerated denim, melt-blown nonwoven fabric, or the like. The above-mentioned automotive interior material may be a known type of interior material, and is preferably particularly suitable for floor carpets, instrument panel insulation pads (iso dash pads), trunk mats, and the like in view of excellent sound absorption coefficient, adhesive strength, heat resistance, and low emission of volatile organic compounds.

Modes for carrying out the invention

The present invention will be described in more detail by the following examples, which should not be construed as limiting the scope of the present invention but as facilitating the understanding of the present invention.

Example 1

38 mol% of the compound represented by the following chemical formula 1 and 3 mol% of the compound represented by the following chemical formula 2 were charged as diol components, 59 mol% of ethylene glycol was charged as the remaining diol component, 100 mol% of terephthalic acid was charged as an acid component, and the acid component and the diol component were subjected to esterification reaction at a ratio of 1:1.2 at a temperature of 250℃and a pressure of 1140 torr to obtain an ester reactant, the reaction rate of which was 97.5%. The ester reactant thus formed was transferred to a polycondensation reactor, 15ppm (based on titanium element) of a compound represented by the following chemical formula 3 was charged as a polycondensation catalyst, 25ppm (based on phosphorus element) of triethyl phosphate was charged as a heat stabilizer, and the temperature was raised to 285℃while gradually lowering the final pressure to 0.5 torr to carry out polycondensation reaction, whereby a copolyester was obtained, which was prepared into polyester chips having a width, a length and a height of 2mm×4mm×3mm by a conventional method.

Then, in order to prepare a core-sheath type composite fiber having the above-mentioned copolyester as a sheath and polyethylene terephthalate (PET) as a core with an intrinsic viscosity of 0.65dl/g, the above-mentioned copolyester chips were fed into hoppers, respectively, and then melted, respectively, and then, after feeding into core-sheath type spinnerets, composite spinning was performed at a spinning speed of 1000mpm at a temperature of 275℃so that the weight ratio of the core to the sheath became 5:5, and then, 3.0 times was drawn to prepare a core-sheath type thermoadhesive composite fiber having a fiber length of 51mm and a fineness of 4.0de as shown in Table 1 below.

[ chemical formula 1]

[ chemical formula 2]

[ chemical formula 3]

The prepared core-sheath type composite fiber and polyethylene terephthalate short fiber (fiber length is 51mm, fineness is 4.0 de) were mixed in a ratio of 5:5, and then subjected to heat treatment at 120 ℃, 140 ℃ and 160 ℃ respectively, thereby preparing a total of three fiber assemblies having a basis weight of 35 g/square meter.

< examples 2 to 14>

The same procedure as in example 1 was repeated except that the composition ratio of the monomers used for producing the copolyester was changed as shown in the following tables 1, 2 and 3 to prepare core-sheath type conjugate fibers as shown in the following tables 1, 2 and 3, and the fiber assemblies were obtained using the same.

Comparative examples 1 to 4 ]

The polyester chips shown in table 2 and core-sheath type composite fibers using the same were prepared in the same manner as in example 1, except that the compositions of the monomers used for preparing the copolyesters were changed as shown in table 2 below, and fiber assemblies were obtained using the polyester chips.

Experimental example 1]

The following physical properties of the three fiber assemblies according to examples and comparative examples or the copolyester chips or core-sheath type composite fibers as intermediates in the production of the fiber assemblies were evaluated, and the results are shown in tables 1 to 3 below.

1. Intrinsic viscosity

After the copolyester chips were melted for 30 minutes at 110℃and a concentration of 2.0g/25ml using o-chlorophenol (Ortho-Chloro-phenyl) as a solvent, the temperature was kept constant for 30 minutes at 25℃and analyzed by an automatic viscosity measuring device connected with a Canon (CANON) viscometer.

2. Glass transition temperature, melting point

The glass transition temperature and the melting point of the copolyester chips were measured by a differential scanning calorimeter, and the temperature rise rate of 20℃per minute was used as the analysis conditions.

3. Drying time of copolyester chip

After the polycondensation of the copolymerized polyester resin chips (chips), the moisture content was measured in a vacuum dryer at 55℃for 4 hours, and the time when the measured moisture content was 100ppm or less was expressed as the drying time.

4. Storage stability of staple fibers

500g of the prepared coreThe sheath type composite fiber was subjected to application of 2kgf/cm in a chamber having a temperature of 40℃and a relative humidity of 45% ² After 3 days, 10 panelists were asked to visually observe the state of the weld between the fibers, and as a result, the average value was calculated after evaluating the results by 0 to 10 points on the basis that the non-welding was 10 points and the total welding was 0 points. As a result, the average value is 9.0 or more, it is very excellent (excellent), the average value is 7.0 or more and less than 9.0, it is excellent (o), the average value is 5.0 or more and less than 7.0, it is normal (Δ), and the average value is less than 5.0, it is poor (x).

5. Spinning operability

In the core-sheath type composite fiber as the second fiber spun in the same content in the examples and comparative examples, the number of droplets (that is, a block obtained by welding a part of the fiber bundle passing through the spinneret or welding the fiber bundle irregularly after the yarn breakage) generated during the spinning process was counted by the droplet detector, and the number of droplets generated in the other preparation examples and comparative preparation examples was expressed as a relative percentage based on the number of droplets generated in preparation example 1 as 100.

6. Evaluation of dye uptake

After a dyeing process of a dye solution containing 2 weight percent of blue (blue) dye based on the weight of the core-sheath type composite fiber was performed at a bath ratio of 1:50 for 60 minutes at a temperature of 90 ℃, the spectral reflectance of the dyed composite fiber in a visible region (360 nm to 740nm, at an interval of 10 nm) was measured by using a color measuring system of KURABO corporation, and Total K/S value, which is a dye uptake index according to the CIE1976 specification, was calculated to evaluate the dyeing yield of the dye.

7. Adhesive strength

After three kinds of fiber assemblies were each formed into test pieces having a width, a length and a height of 100mm×20mm×10mm, the adhesive strength was measured by a universal tester (UTM, universal testing machine) according to the KS M ISO 36 method.

On the other hand, if the morphology is deformed by excessive shrinkage during the heat treatment, the adhesive strength is not evaluated, but is evaluated as "morphology deformation".

8. Soft touch feeling

Of the three fiber aggregates, the fiber aggregate prepared by heat treatment at a temperature of 140 ℃ was subjected to sensory examination by a group of 10 professionals in the same industry, and the evaluation results were distinguished in the following manner: if 8 or more are judged to be soft, it is indicated to be excellent (excellent), if 6 to 7 are judged to be soft, it is indicated to be good (o), if 4 to 5 are judged to be soft, it is indicated to be normal (Δ), and if less than 4 are judged to be soft, it is indicated to be bad (x).

TABLE 1

TABLE 2

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TABLE 3 Table 3

As shown in tables 1 to 3, it was confirmed that the drying time was significantly prolonged (comparative examples 1 to 3) or the spinning operability was significantly poor (comparative examples 2 and 3), the storage stability of the short fibers was very poor (comparative examples 2 and 3), or the appearance was deformed in the evaluation of the adhesive strength at different temperatures (comparative example 4), and it was confirmed that these comparative examples could not satisfy all physical properties at the same time, but it was confirmed that the examples exhibited all physical properties at excellent levels.

On the other hand, in examples, example 13 containing a larger amount of the compound represented by chemical formula 2 than that of the compound represented by chemical formula 1 exhibited morphological deformation in the adhesive strength evaluation at different temperatures compared with other examples, and thus it was confirmed that it was not suitable for achieving the intended physical properties.

< examples 15 to 29>

The fiber assemblies shown in Table 4 below were prepared in the same manner as in example 1, except that the composition ratios of the monomers used for preparing the copolyesters were changed as shown in Table 4 below. At this time, the heat treatment temperature for preparing the fiber assembly was 140 ℃.

Comparative example 5 ]

Experimental example 2

The following physical properties of the heat-bondable fibers, the fiber assemblies obtained, or the copolyester chips as intermediates in the production of the fiber assemblies according to examples 15 to 29 and comparative example 5 were evaluated, and the results thereof are shown in table 4 below.

1. Intrinsic viscosity

The intrinsic viscosity was measured in the same manner as in experimental example 1.

2. Volatile organic compound content

The determination was made according TO the EPA TO-14 method.

3. Soft touch feeling

The touch was measured in the same manner as in experimental example 1.

TABLE 4 Table 4

As can be seen from table 4, in the cases of examples 15 to 29, the amount of volatile organic compounds generated by the heat-bondable fibers was small compared with comparative example 5, and therefore the fiber aggregate including the heat-bondable fibers was suitable for use in automotive interior materials.

< examples 30 to 33>

A fiber assembly was prepared in the same manner as in example 21, except that the mixing ratio of the heat-bondable fibers and the polyethylene terephthalate support fibers was changed as shown in table 5 below. At this time, the heat treatment temperature for preparing the fiber assembly was 165 ℃.

Comparative example 6 ]

A fiber assembly was prepared in the same manner as in example 30, except that the composition of the heat-bondable fibers and the mixing ratio with the polyethylene terephthalate fibers were changed as shown in Table 5 below.

< comparative examples 7 to 8>

A fiber assembly was prepared in the same manner as in example 21, except that the composition of the heat-bondable fibers and the mixing ratio with the polyethylene terephthalate fibers were changed as shown in Table 5 below. At this time, the heat treatment temperature for preparing the fiber assembly was 165 ℃.

Experimental example 3 ]

The following physical properties of the fiber assemblies of examples 30 to 33 and comparative examples 6 to 8 were evaluated, and the results are shown in table 5 below.

1. Initial cotton opening Property

When a web was produced using a laboratory carding machine, the initial opening degree was confirmed, and an internal expert performed relative opening degree evaluations, as evaluation results, which were evaluated as very excellent (excellent), excellent (good), normal (delta), and poor (x).

2. Comb property

When a web was produced using a laboratory carding machine, an internal expert performed evaluation by comparing relative workability, and as a result of the evaluation, the evaluation was very excellent (excellent), excellent (o), ordinary (Δ), and poor (x).

3. Adhesive strength

The adhesive strength was measured according to KS M ISO 36 method using a universal tester (universal testing machine, UTM) in the same manner as in experimental example 1.

4. Workability and workability of the product

In evaluating nonwoven fabrics, an internal expert performs evaluation by comparing relative workability with evaluation items for evaluating process workability such as initial opening property, carding property, processing speed, and the like, and as evaluation results, the evaluation was very excellent (excellent), excellent (o), normal (Δ), and poor (x).

5. Average sound absorption coefficient and sound absorption coefficient according to frequency

The measurement was performed according to KS F2805.

6. Modulus of resilience

The iron ball was dropped onto the test piece from a predetermined height, and the anti-bouncing height was measured (JIS K-6301, unit:%). The test piece was formed into a square having a side length of 50mm or more and a thickness of 50mm or more, a steel ball having a weight of 16g and a diameter of 16mm was dropped from a height of 500mm onto the test piece to measure the maximum rebound height, and then the rebound values of three test pieces were measured continuously for 1 minute or more at least 3 times, respectively, and the intermediate value was determined as the rebound modulus (%).

TABLE 5

From table 5, it was confirmed that the fiber aggregate of the example of the present invention was excellent in initial cotton opening property, comb property, adhesive strength, modulus of elasticity, processability, and sound absorption coefficient, as compared with the fiber aggregate of the comparative example, and was confirmed to be suitable for use in automotive interior materials.

While the embodiment of the present invention has been described above, the gist of the present invention is not limited to the embodiment of the present invention, and other embodiments can be easily proposed by those skilled in the art by adding, modifying, deleting, adding, etc. constituent elements within the same gist scope, and these fall within the gist of the present invention.

Claims

1. A fiber aggregate for an automotive interior material, comprising:

A heat-bondable fiber; and

Polyester-based support fibers having a melting point above 250 ℃,

the weight ratio of the heat-bondable fibers to the supporting fibers is 20:80 to 50:50,

the heat-bondable fiber contains a copolyester obtained by polycondensation of an esterified compound obtained by reaction of an acid component containing terephthalic acid and a glycol component,

the diol component contains ethylene glycol, 20 to 40 mol% of the compound represented by the above chemical formula 1, and 0.8 to 10 mol% of the compound represented by the above chemical formula 2, and does not contain diethylene glycol.

[ chemical formula 1]

[ chemical formula 2]

2. The fiber aggregate for automotive interior material according to claim 1, wherein the total content of the compound represented by chemical formula 1 and the compound represented by chemical formula 2 is 30 mol% to 45 mol% of the diol component.

3. The fiber aggregate for automotive interior material according to claim 1, wherein the weight ratio of the heat-bondable fiber to the supporting fiber is 30:70 to 40:60.

4. The fiber aggregate for automotive interior material according to claim 1, wherein the diol component comprises 30 to 40 mol% of the compound represented by the chemical formula 1 and 0.8 to 6 mol% of the compound represented by the chemical formula 2.

5. The fiber aggregate for automotive interior material according to claim 1, wherein the average sound absorption coefficient is 0.35 or more in a frequency range of 400Hz to 2000 Hz.

6. The fiber aggregate for automotive interior material according TO claim 1, wherein the heat-bondable fiber has a discharge amount of 2600ppb or less of volatile organic compounds measured by the U.S. EPA TO-14 method.

7. The fiber aggregate for automotive interior material according to claim 1, wherein the adhesive strength according to KS MISO 36 is 130N/25 mm to 200N/25 mm.

8. The fiber aggregate for automotive interior material according to claim 1, characterized in that the sound absorption coefficient according to KS F2805 satisfies the following condition:

(1) At the frequency of 1000Hz, the sound absorption coefficient is more than 0.53;

(2) At 2000Hz, the sound absorption coefficient is above 0.73.

9. The fiber aggregate for automotive interior material according to claim 1, characterized in that the sound absorption coefficient according to KS F2805 satisfies the following condition:

(3) At 3000Hz, the sound absorption coefficient is more than 0.83;

(4) At 4000Hz, the sound absorption coefficient is above 0.92.

10. An automotive interior material comprising the fiber aggregate for automotive interior material according to any one of claims 1 to 9.