JP7419540B2 - Fiber aggregate for automobile interior materials and automobile interior materials containing the same - Google Patents

Description

The present invention relates to a fiber aggregate for automobile interior materials, and more specifically, it has excellent tactile sensation, sound absorption coefficient, adhesive strength, rebound modulus, and processability, has excellent heat resistance, minimizes changes over time, and is free of VOCs. The present invention relates to a fiber aggregate for automobile interior materials that is particularly suitable for automobiles in which emissions are significantly reduced and a sealed environment is realized, and to automobile interior materials containing the same.

Generally, synthetic fibers have a high melting point, which often limits their uses. In particular, when used as a core for adhering fibers or as an adhesive that is inserted between tape-like textiles and bonded under pressure, the textiles themselves may deteriorate due to heating, and Because of the inconvenience of having to use special equipment, there is a demand for easy bonding using a simple hot press without the use of such special equipment.

Conventional low melting point polyester fibers are used as hot melt type binder fibers for the purpose of bonding different types of fibers in interfiber structures used in the production of mattresses, automobile interior materials, or various nonwoven fabric padding applications. It has been widely used.

For example, U.S. Patent No. 4,129,675 introduces a low melting point polyester copolymerized using terephthalic acid (TPA) and isophthalic acid (IPA), and also, Korean Patent No. 10-1216690 discloses a low melting point polyester fiber containing isophthalic acid and diethylene glycol to improve adhesion.

However, although the conventional low-melting point polyester fibers described above can have spinnability and adhesive properties above a certain level, the rigid ring structure of the modifier makes it difficult to create interior materials for automobiles that feel hard after thermal bonding. There are problems to be realized.

In addition, as development progresses toward lower melting points and lower glass transition temperatures in order to express binder properties, the heat resistance of polyesters that have been developed has deteriorated, resulting in storage conditions that exceed 40°C in summer. However, there is a problem in that significant changes occur over time, and bonding between polyester fibers occurs during storage, resulting in a significant decrease in storage stability. In particular, the indoor temperature of a car parked outside during the summer can rise to over 60 degrees Celsius, and under these conditions, the aging of interior materials caused by the use of polyester fibers, which have poor heat resistance, becomes a problem. obtain.

On the other hand, automobiles are generally operated in a sealed state from the outside, and in particular, the number of cars operated in a sealed state is increasing due to the influence of fine dust. As a result, the quality of the air in the interior space of automobiles is important, but there have been reports of problems with the release of volatile organic compounds (VOCs) from interior materials installed in the interior space. The reality is that it poses a problem for the health of passengers.

Therefore, there is currently a need to develop automotive interior materials that improve tactility, sound absorption coefficient, adhesive strength, rebound modulus, and processability, minimize changes over time, and significantly reduce VOCs emissions. be.

The present invention was devised in consideration of the above points, and has excellent tactile sensation, sound absorption coefficient, adhesive strength, rebound modulus, and processability, and has excellent heat resistance that minimizes changes over time. An object of the present invention is to provide a fiber assembly for automobile interior materials that is particularly suitable for automobiles in which the emission of VOCs is significantly reduced and a sealed environment is realized, and an automobile interior material containing the same.

In order to solve the above-mentioned problems, the present invention provides an esterified compound in which an acid component containing terephthalic acid and a diol component containing a compound represented by the following chemical formula 1 and a compound represented by the chemical formula 2 are reacted with ethylene glycol. and a polyester support fiber having a melting point higher than 250°C, the heat adhesive fiber and the support fiber being contained in a weight ratio of 20:80 to 50:50. The present invention provides fiber aggregates for automobile interior materials.

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 mol % of the diol component.

Further, the content (mol %) of the compound represented by Chemical Formula 1 among the diol components may be greater than the content (mol %) of the compound represented by Chemical Formula 2.

Further, the diol component may be substantially free of diethylene glycol.

Further, the acid component may further include isophthalic acid in an amount of 1 to 10 mol% based on the acid component.

Further, in the diol component, the compound represented by the chemical formula 1 may be contained in an amount of 1 to 40 mol%, and the compound represented by the chemical formula 2 may be contained in an amount of 0.8 to 20 mol%. Among the diol components, the compound represented by the chemical formula 1 is 20 to 40 mol%, and the compound represented by the chemical formula 2 is 0.8 to 10 mol%, more preferably the compound represented by the chemical formula 1. may be contained in an amount of 30 to 40 mol%, and the compound represented by Formula 2 may be contained in an amount of 0.8 to 6 mol%.

Further, the copolyester may have a glass transition temperature of 60 to 75°C, more preferably 65 to 72°C.

Further, the copolyester may have an intrinsic viscosity of 0.500 to 0.800 dl/g.

Further, the heat-adhesive fiber and the support fiber may be included in a weight ratio of 30:70 to 40:60.

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

In addition, the sound absorption coefficient based on KS F 2805 is (1) a sound absorption coefficient of 0.53 or more at a frequency of 1000Hz, (2) a sound absorption coefficient of 0.73 or more at a frequency of 2000Hz, (3) a sound absorption coefficient of 0 at a frequency of 3000Hz. (4) The sound absorption coefficient may be 0.92 or more at a frequency of 4000 Hz.

Further, the heat-adhesive fiber may have a VOCs emission amount of 2600 ppb or less, more preferably 2200 ppb or less, as measured based on the US EPA TO-14 method.

Further, the adhesive strength based on KSM ISO 36 may be 130 to 200 N/25 mm.

Further, the rebound modulus may be 45 to 60%.

Further, the present invention provides an automobile interior material including the fiber aggregate for automobile interior material according to the present invention.

The fiber aggregate for interior materials according to the present invention has excellent feel, sound absorption coefficient, adhesive strength, rebound modulus, and processability. In addition, its excellent heat resistance minimizes deterioration over time, making it highly suitable for use as an interior material for automobiles, where high indoor temperatures occur during outdoor parking in the summer. Furthermore, the emission of VOCs is significantly reduced, making it highly suitable for automobile interior materials that increasingly operate in closed environments, and thus can be widely applied in related fields.

FIG. 2 is a schematic cross-sectional view of a thermal adhesive fiber included in an example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily carry out the embodiments. The present invention may be embodied in a variety of different forms and is not limited to the embodiments described herein.

The fiber aggregate for automobile interior materials according to the present invention contains an esterified compound obtained by reacting an acid component containing terephthalic acid with ethylene glycol and a diol component containing a compound represented by the following chemical formula 1 and a compound represented by the chemical formula 2. It is realized by containing heat-adhesive fibers containing polycondensed copolyester and polyester support fibers having a melting point higher than 250° C. in a weight ratio of 20:80 to 50:50.

The heat-adhesive fiber is a polycondensed product of an acid component containing terephthalic acid and an esterified compound obtained by reacting ethylene glycol with a diol component containing a compound represented by the following chemical formula 1 and a compound represented by the chemical formula 2. It is a fiber formed containing polyester, which serves to attach the polyester support fibers described below through heat fusion, and also serves to ensure the shape and mechanical strength of the fiber aggregate. be.

First, the acid component includes terephthalic acid, and other than terephthalic acid, aromatic polycarboxylic acid having 6 to 14 carbon atoms, aliphatic polycarboxylic acid having 2 to 14 carbon atoms, and/or sulfonic acid. It can further include metal salts.

The aromatic polyhydric carboxylic acid having 6 to 14 carbon atoms is an acid component used for producing polyester, and any known one can be used without limitation, but dimethyl terephthalate and isophthalic acid are preferably used. and dimethyl isophthalate, more preferably isophthalic acid from the viewpoint of reaction stability with terephthalic acid, ease of handling, and economical aspects. .

In addition, the aliphatic polycarboxylic acid having 2 to 14 carbon atoms is an acid component used for producing polyester, and any known one can be used without limitation, but there are no limited examples thereof. 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. There may be one or more of them.

Furthermore, the sulfonic acid metal salt may be sodium 3,5-dicarbomethoxybenzene sulfonate.

On the other hand, other components that may be included as the acid component other than terephthalic acid may reduce the heat resistance of the copolyester, so it is preferably not included. In particular, when an acid component such as isophthalic acid or dimethyl isophthalic acid is further included, the content of VOCs generated during the polycondensation process of the copolyester, such as the content of acetaldehyde, may increase, while the melting point of the copolyester may further decrease. It is also difficult to vaporize and remove acetaldehyde generated during polymerization through post-processes such as heat treatment, resulting in a high content of acetaldehyde in the manufactured fibers. Therefore, if isophthalic acid is further included, it may be included in an amount of 1 to 10 mol% based on the acid component, and if it is included in an amount exceeding 10 mol%, the content of acetaldehyde may be excessively increased. , the embodied thermoadhesive fibers may not be suitable for automotive interior material applications.

Next, the diol component includes ethylene glycol and a compound represented by Chemical Formula 1 and a compound represented by Chemical Formula 2 below.

First, the compound represented by Formula 1 can lower the crystallinity and glass transition temperature of the produced copolyester, thereby exhibiting excellent thermal adhesive performance. In addition, after being manufactured into fibers, dyeing can be carried out under normal pressure conditions during the dyeing process, making the dyeing process easier. It also has excellent dyeing properties, improves washing fastness, and improves the texture of the fiber aggregate. can be done. Preferably, the compound represented by Formula 1 among the diol components may be included in an amount of 20 to 40 mol%, more preferably 30 to 40 mol%. In particular, when the compound represented by Chemical Formula 1 is contained in an amount of 20 mol% or more, the thermal adhesion properties at low temperatures of the copolyester embodied together with the compound represented by Chemical Formula 2, which will be described later, can be further improved. When manufacturing polyester into chips, there is an advantage that the drying time can be significantly shortened and an increased effect can be exerted on reducing the content of VOCs released from the thermoadhesive fibers.

If the compound represented by Formula 1 is contained in an amount less than 20 mol% based on the diol component, it may have excellent spinnability, but the adhesion temperature may become high or the thermal adhesion properties may deteriorate, making it difficult to use. There is a fear that the application may be limited. In addition, the content of VOCs emitted from the heat-adhesive fibers may increase. Furthermore, if the compound represented by chemical formula 1 is contained in an amount exceeding 40 mol%, the spinnability into heat-adhesive fibers is not good, which may cause problems such as difficulty in commercialization. Crystallinity may increase and thermal adhesion properties may deteriorate.

The compound represented by Chemical Formula 2 further improves the thermal adhesive properties of the copolyester produced together with the compound represented by Chemical Formula 1, but the glass transition temperature of the compound represented by Chemical Formula 1 is significantly increased. It is possible to prevent the storage temperature from decreasing, thereby minimizing changes over time and improving storage stability despite the storage temperature of 40° C. or higher and the temperature inside a car that rises to 60° C. or higher in summer. In relation to thermal adhesiveness, the compound represented by Chemical Formula 2 is used in combination with the compound represented by Chemical Formula 1 to develop suitable shrinkage characteristics for the thermally adhesive fiber using the copolyester. By developing such characteristics, the point adhesion force is further increased during thermal bonding, thereby making it possible to exhibit improved thermal bonding characteristics.

Preferably, the compound represented by Formula 2 in the diol component may be contained in an amount of 0.8 to 10 mol%, more preferably 0.8 to 6 mol%.

If the compound represented by chemical formula 2 is contained in less than 0.8 mol% based on the diol component, it will be difficult to improve the desired heat resistance, the storage stability will be poor, and the change over time will be very large. There is a fear that you will get it. In addition, the content of VOCs emitted from the heat-adhesive fibers may increase.

Additionally, if the compound represented by chemical formula 2 is contained in an amount exceeding 10 mol%, the spinnability into heat-adhesive fibers will be poor, considering that it will be used together with the compound represented by chemical formula 1 mentioned above. Therefore, commercialization may be difficult, and in some cases, if even isophthalic acid is additionally included, the crystallinity is sufficiently reduced and the improvement in adhesion is negligible, and the added isophthalic acid is When the content increases, the crystallinity increases and the excellent thermal adhesion properties at the desired temperature may be significantly deteriorated, so that the object of the invention may not be achieved. Furthermore, when it is formed into a fiber, it exhibits significantly large shrinkage, making it difficult to process it into a fiber aggregate or 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% of the diol component, and more preferably Preferably, it may be contained in an amount of 33 to 41 mol%. If these are contained in an amount less than 30 mol%, the crystallinity of the copolyester will increase and a high melting point will occur, or it will be difficult to achieve a softening point at a low temperature, and the temperature at which thermal bonding is possible will be significant. and may not exhibit excellent thermal adhesive properties at low temperatures. In addition, the content of VOCs emitted from the heat-adhesive fibers may increase.

Furthermore, if the compound represented by Formula 2 is contained in an amount exceeding 45 mol%, the polymerization reactivity and spinnability may decrease significantly, and the crystallinity of the copolyester produced may increase. It may be difficult to develop high thermal adhesive properties at the desired temperature.

At this time, the compound represented by Chemical Formula 1 may be included in the diol component in a larger amount (mol %) than the compound represented by Chemical Formula 2. If the compound represented by Chemical Formula 1 is contained in a smaller amount or the same amount as the compound represented by Chemical Formula 2, it will be difficult to develop the desired thermal adhesive properties, and the adhesive will have to be bonded at a high temperature, so it will not be developed. There may be restrictions on the use of the product. Furthermore, there is a possibility that processing into developed products may become difficult due to excessive shrinkage characteristics.

Meanwhile, the diol component may further include other types of diol components in addition to the compound represented by Formula 1, the compound represented by Formula 2, and ethylene glycol.

The other type of diol component may be a known diol component used in the production of polyester, so the present invention is not particularly limited thereto. It may be an aliphatic diol component, and specifically includes 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, propylene glycol, trimethyl glycol, tetramethylene glycol, pentamethyl glycol, and hexane diol. Any one or more selected from the group consisting of methylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, undecamethylene glycol, dodecamethylene glycol, and tridecamethylene glycol good.

However, in order to have the desired level of thermal adhesive properties and heat resistance, it is preferable that the other types of diol components are not further included, and in particular, diethylene glycol does not need to be included in the diol components. If diethylene glycol is included in the diol component, the glass transition temperature will drop sharply, and even if the compound represented by Formula 2 is included, the desired level of heat resistance may not be achieved. In addition, the content of VOCs released during use may increase significantly. On the other hand, the diol component does not contain diethylene glycol, meaning that diethylene glycol is intentionally added as a monomer for the production of copolyester. This does not mean that it does not contain diethylene glycol, which is generated as a by-product in the esterification reaction and polycondensation reaction of acid components and diol components. Since diethylene glycol may occur naturally as a by-product, in accordance with one embodiment of the present invention, the sheath formed with the copolyester may include diethylene glycol generated as a by-product, and the content of diethylene glycol contained therein may be reduced. may be less than 4% by weight based on the weight of the copolyester chip or the sheath made of copolyester alone. On the other hand, if the content of diethylene glycol generated as a by-product exceeds the appropriate level, it will increase the pack pressure during spinning into fibers, induce frequent yarn breakage, and significantly reduce spinnability, and the content of VOCs released. In particular, the amount of acetaldehyde released may increase significantly.

The acid component and diol component described above can be produced into a copolyester through an esterification reaction and polycondensation using synthesis conditions known in the field of polyester synthesis. At this time, the acid component and the diol component may be added so as to react at a molar ratio of 1:1.0 to 5.0, preferably 1:1.0 to 2.0, but are limited to this. It's not a thing.

On the other hand, the acid component and the diol component are mixed at the same time in an appropriate molar ratio as above, and then subjected to esterification reaction and polycondensation to produce a copolyester, or among the acid component and diol component, ethylene A copolyester can be produced through the esterification reaction and polycondensation by adding the compound represented by Chemical Formula 2 during the esterification reaction between glycol and the compound represented by Chemical Formula 1, and the present invention addresses this. Not particularly limited.

The esterification reaction may further include a catalyst. As the catalyst, a catalyst that is normally used in the production of polyester can be used, and as a non-limiting example, it can be produced under a metal acetate catalyst.

Further, the esterification reaction may be preferably performed at a temperature of 200 to 270° C. and a pressure of 1100 to 1350 Torr. If the above conditions are not met, there may be problems such as the esterification reaction time becoming longer or the reactivity being lowered, making it impossible to form an esterified compound suitable for the polycondensation reaction.

In addition, the polycondensation reaction may be performed at a temperature of 250~300°C and a pressure of 0.3~1.0 Torr, and if the above conditions are not met, the reaction time may be delayed, the polymerization degree may be There may be problems such as a decrease in the temperature and induction of thermal decomposition.

At this time, a catalyst may be further included during the polycondensation reaction. The catalyst may be any known catalyst used in the production of polyester resins and may be used without any limitation. However, preferably, it may be a titanium-based polymerization catalyst, and more specifically, it may be a titanium-based polymerization catalyst represented by the following chemical formula 3.

The titanium-based polymerization catalyst represented by the chemical formula 3 is stable even in the presence of water molecules, so it will not be deactivated even if added before the esterification reaction, which produces a large amount of water as a by-product, resulting in a shorter time than conventional methods. Esterification reaction and polycondensation reaction can proceed during the process, and coloring due to yellowing can be suppressed through these reactions. The catalyst may be contained in an amount of 5 to 40 ppm in terms of titanium atoms based on the total weight of the copolyester to be obtained, which is preferable because it improves the thermal stability and color tone of the copolyester. If the content is less than 5 ppm in terms of titanium atoms, it may be difficult to properly promote the esterification reaction, and if the content exceeds 40 ppm, reactivity may be promoted but coloring may occur. There may be problems with this.

Further, the esterification reaction may be preferably performed at a temperature of 200 to 270° C. and a pressure of 1100 to 1350 Torr. If the above conditions are not met, there may be problems such as the esterification reaction time becoming longer or the reactivity being lowered, making it impossible to form an esterified compound suitable for the polycondensation reaction.

In addition, the polycondensation reaction may be performed at a temperature of 250~300°C and a pressure of 0.3~1.0 Torr, and if the above conditions are not met, the reaction time may be delayed, the polymerization degree may be There may be problems such as a decrease in the temperature and induction of thermal decomposition.

Meanwhile, a heat stabilizer may be further included during the polycondensation reaction. The thermal stabilizer is for preventing color change due to thermal decomposition at high temperatures, and may be a phosphorus compound. As the phosphorus compound, it is preferable to use, for example, phosphoric acids such as phosphoric acid, monomethyl phosphoric acid, trimethyl phosphoric acid, triethyl phosphoric acid, and derivatives thereof, and among these, especially trimethyl phosphoric acid or triethyl phosphoric acid. is more preferable because it is more effective. The amount of the phosphorus compound to be used is preferably 10 to 30 ppm in terms of phosphorus atoms based on the total weight of the copolyester finally obtained. If the phosphorus-based heat stabilizer is used in an amount less than 10 ppm, it is difficult to prevent high-temperature thermal decomposition and the copolyester may discolor, and if it exceeds 30 ppm, it may be disadvantageous from the viewpoint of manufacturing costs and During the condensation reaction, there may be a problem that a reaction delay phenomenon occurs due to suppression of catalyst activity by a thermal stabilizer.

Moreover, the copolyester can further include a complementary color agent. The complementary coloring agent is used for color tone adjustment to make the hue of the dye stronger and better in the dyeing process that is carried out after spinning into fibers, and is a coloring agent known in the textile field. Non-limiting examples of which can be added include base dyes, pigments, vat dyes, disperse dyes, organic pigments, and the like. However, preferably, a mixture of blue and red dyes can be used. This is because cobalt compounds, which are commonly used as complementary color agents, are highly harmful to the human body and are undesirable, whereas complementary color agents mixed with blue and red dyes are harmless to the human body. It is preferable because there is. Further, when a mixture of blue and red dyes is used, there is an advantage that the color tone can be finely controlled. For example, the blue dye may be so
For example, the red dye may be solvent blue 104, solvent blue 122, solvent blue 45, etc.
111, solvent red 179, solvent red 195, etc. In addition, the blue dye and the red dye may be mixed at a weight ratio of 1:1.0 to 3.0, which is advantageous in achieving a remarkable effect on fine color tone control.

The complementary color agent may be included in an amount of 1 to 10 ppm based on the total weight of the copolyester, but if it is included in an amount less than 1 ppm, it may be difficult to achieve the desired level of complementary color properties, and if the amount exceeds 10 ppm. In this case, there may be a problem that the L value decreases, the transparency decreases, and the color becomes dark.

The copolyester prepared through the above method may have an intrinsic viscosity of 0.5 to 0.8 dl/g. If the intrinsic viscosity is less than 0.5 dl/g, there may be problems such as difficulty in forming the cross section, and if the intrinsic viscosity exceeds 0.8 dl/g, the pack pressure may be Because of the high viscosity, there may be problems with spinnability.

Further, the copolyester may have a glass transition temperature of 60 to 75° C., which may be more advantageous in achieving the objects of the present invention. If the glass transition temperature is less than 60°C, the thermoadhesive fiber containing the copolyester or the article containing the copolyester may age over time even under temperature conditions exceeding 40°C, such as in the summer. The changes are large, and the changes over time can increase significantly, especially when considering the temperature inside a car in the summer. In addition, when producing thermal adhesive fibers, the occurrence of bonding between copolyester chips increases, which may cause spinning defects. Furthermore, after being incorporated into fibers, the shrinkage properties may be excessively developed, and the bonding properties may be deteriorated. Further, due to limitations in heat treatment required in a drying process after chip formation, a post-processing process after spinning into fibers, etc., there may be a problem that the time required for the process becomes long or that the process cannot be carried out smoothly.

Furthermore, if the glass transition temperature exceeds 75° C., the thermal bonding properties may be significantly degraded, and the temperature at which the bonding process is performed may be limited to a high temperature.

The above-mentioned copolyesters can be used alone to form thermally bondable fibers. Alternatively, the above-mentioned copolyester may be provided as a sheath part 12 surrounding the core part 11 to form a core-sheath type thermoadhesive fiber 10, as shown in FIG.

At this time, the core portion 11 may be made of a known polyester that has higher heat resistance and mechanical strength than the copolyester that is the sheath portion, such as polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, etc. However, it is not limited to this. The core-sheath type heat-adhesive fiber may be, for example, one obtained by composite spinning a core part and a sheath part at a weight ratio of 8:2 to 2:8, but is not limited thereto. , the ratio can be appropriately adjusted depending on the purpose. The spinning conditions for the conjugate fiber, the spinning device, and the steps such as cooling and stretching the conjugate fiber after spinning may be performed using conditions, devices, and processes known in the art, or by appropriately modifying them. The present invention is not particularly limited to this. Further, as an example, the composite fiber may be spun at a spinning temperature of 270 to 290°C, and may be drawn 2.5 to 4.0 times after spinning.

On the other hand, the thermal adhesive fiber may have a fineness of 1 to 15 deniers, and a fiber length of 1 to 100 mm, for example, but is not limited thereto.

In addition, the heat-adhesive fiber has a VOCs generation amount of 2600 ppb or less, more preferably 2200 ppb or less, based on the US EPA TO-14 method, so that it is safe for the human body in a closed environment such as the inside of a car. Since the amount of harmful components generated is significantly small, it can be very useful as an automobile interior material, and has the advantage of reducing odor of the interior material.

Next, support fibers included in the fiber assembly together with the above-mentioned thermal adhesive fibers will be explained.

The supporting fibers include a polyester component for compatibility with the heat-adhesive fibers, and serve to ensure mechanical strength, shape retention, and heat resistance of the fiber aggregate. Therefore, the polyester component may have a melting point higher than 250° C., which may be more advantageous in achieving the objects of the present invention.

The supporting fibers may have a fineness of 1 to 10 deniers, and a fiber length may be, for example, 1 to 100 mm, but are not limited thereto.

The support fiber may be any known polyester component having a melting point of over 250° C., and may be polyethylene terephthalate, for example, but is not limited thereto.

The above-mentioned thermal adhesive fibers and support fibers may form a fiber aggregate in a weight ratio of 20:80 to 50:50, preferably 30:70 to 40:60. If the weight of the supporting fibers exceeds four times the weight of the heat-adhesive fibers, the bonding strength of the fiber assembly may be reduced, resulting in insufficient adhesive properties. In addition, if the supporting fibers are included in a weight less than 1 times the weight of the heat-adhesive fibers, the sound absorption coefficient, tactile sensation, and shape stability of the fiber aggregate will be significantly reduced, and the initial opening property and carburizing properties will be significantly reduced. Problems that make it difficult to commercialize as there is a risk of a significant decrease in workability such as threading properties and poor spinnability, and the rigid ring structure of the modifier results in non-woven fabrics or fabrics that feel stiff after thermal bonding. There is a possibility that it may be done.

The fiber aggregate including the heat-adhesive fibers and supporting fibers may be in the form of a known fabric, such as a woven fabric, a knitted fabric, or a nonwoven fabric, but as an example, the fiber aggregate may have a directionality based on the longitudinal direction of the fibers. It may also be a non-woven fabric. The nonwoven fabric may be manufactured using a known dry or wet nonwoven fabric manufacturing method, and the present invention is not particularly limited thereto.

For example, the heat-adhesive fibers and supporting fibers may be made of single fibers having a predetermined length, mixed and opened, and then heat treated to form a fiber aggregate. The heat treatment may be performed at a temperature of 100 to 180°C, more preferably 120 to 180°C, through which improved adhesive properties can be exhibited.

The fiber aggregate for automobile interior materials according to an embodiment of the present invention may have a sound absorption coefficient of 0.35 or more within the frequency range of 400 to 2000 Hz measured based on KS F 2805. Further, in condition (1), the sound absorption coefficient may be 0.53 or more at a frequency of 1000 Hz, and more preferably 0.53 to 0.75. Further, in condition (2), the sound absorption coefficient may be 0.73 or more at a frequency of 2000 Hz, and more preferably 0.73 to 0.85. Further, in condition (3), the sound absorption coefficient may be 0.83 or more at a frequency of 3000 Hz, and more preferably 0.83 to 0.95. In condition (4), the sound absorption coefficient may be 0.92 or more at a frequency of 4000 Hz, and more preferably 0.92 to 0.99. Through this, by satisfying a high sound absorption coefficient in a wide frequency band, when used in automobile interior materials, it is possible to prevent the noise from the outside of the car and the noise generated from the car itself from being transmitted into the interior of the car. can do.

Furthermore, the fiber aggregate for automobile interior materials according to an embodiment of the present invention can satisfy an adhesive strength of 130 to 200 N/25 mm, more preferably 140 to 200 N/25 mm, based on KSM ISO 36. A fiber aggregate that satisfies such adhesive strength exhibits excellent mechanical strength, and has advantageous adhesive properties even at the same processing temperature, so that it can be easily molded during processing. Further, the rebound modulus may be 45 to 60%, thereby making it more suitable for automobile interior materials, particularly floor carpets.

Meanwhile, the above-described fiber aggregate for automobile interior materials may be implemented alone or further including recycled denim, melt-blown nonwoven fabric, etc., as an automobile interior material. Said automotive interior materials may be interior materials of known types, preferably floor carpets, ISO dash pads, trunk mats, in view of their excellent sound absorption, adhesive strength, heat resistance and low VOCs emissions. It may be particularly suitable for

<Form for carrying out the invention>
The present invention will be explained in more detail through the following examples, but the following examples are not intended to limit the scope of the present invention, and should be interpreted to aid in understanding 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 as diol components, and 59 mol% of ethylene glycol as the remaining diol component, and 100 mol% of terephthalic acid as the acid component. Then, the acid component and the diol component were esterified at a ratio of 1:1.2 at 250° C. under a pressure of 1140 torr to obtain an ester reactant, and the reaction rate was 97. It was 5%. The formed ester reactant was transferred to a polycondensation reactor, and 15 ppm (based on Ti element) of the compound represented by the following chemical formula 3 as a polycondensation catalyst and 25 ppm (based on P element) as a heat stabilizer were added. Then, while gradually reducing the pressure to a final pressure of 0.5 torr, the temperature was raised to 285°C to perform a polycondensation reaction to produce a copolyester, and then the copolyester was processed horizontally, vertically, and Polyester chips were manufactured, each having a height of 2 mm x 4 mm x 3 mm.

Thereafter, the copolyester chips and PET chips were combined to produce a core-sheath composite fiber having the copolyester as a sheath and polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 dl/g as a core. They were each put into a hopper and melted, and then put into a core-sheath type spinneret, and then compound-spun at 275°C at a spinning speed of 1000 mpm so that the weight ratio of the core and sheath parts was 5:5. 0 times stretching to produce a core-sheath type heat-adhesive conjugate fiber having a fiber length of 51 mm and a fineness of 4.0 de as shown in Table 1 below.

After mixing and opening the manufactured core-sheath type composite fiber and polyethylene terephthalate (PET) single fiber (fiber length 51 mm, fineness 4.0 de) at a ratio of 5:5, the temperature was 120°C, 140°C, and 160°C, respectively. A total of three types of wet-laid nonwoven fabrics having a basis weight of 35 g/m ² were manufactured by heat treatment under the following conditions.

<Examples 2 to 14>
The production is carried out in the same manner as in Example 1, but the composition ratio of the monomers for producing the copolyester is changed as shown in Table 1, Table 2 or Table 3 below. A core-sheath type composite fiber as shown in No. 3 was manufactured and used to realize a fiber assembly.

<Comparative Examples 1 to 4>
The production was carried out in the same manner as in Example 1, but the composition ratio of the monomers for producing the copolyester was changed as shown in Table 2 below, and polyester chips and cores using the same were produced as shown in Table 2 below. A sheath-type composite fiber was produced and used to realize a fiber assembly.

<Experiment example 1>
The following physical properties were evaluated for copolyester chips and core-sheath type thermoadhesive composite fibers, which are intermediates during the production of the three types of fiber aggregates or fiber aggregates embodied in Examples and Comparative Examples, and the results were are shown in Tables 1 to 3 below.

1. Intrinsic viscosity A copolyester chip was melted using Ortho-ChloroPhenol as a solvent at 110°C for 30 minutes at a concentration of 2.0g/25ml, and then kept constant at 25°C for 30 minutes.CANON viscosity The analysis was performed using an automatic viscosity measuring device connected to a viscometer.

2. Glass transition temperature, melting point The glass transition temperature and melting point of the copolyester were measured using a differential thermal analyzer, and the analysis conditions were a temperature increase rate of 20° C./min.

3. Drying time of copolyester chips After the polycondensed copolyester resin was made into chips, the moisture content was measured at 55°C in a vacuum dryer at 4 hour intervals, and the moisture content was determined to be 100 ppm or less. The drying time was expressed as the drying time.

4. Single fiber storage stability 500 g of the produced core-sheath type composite fiber was subjected to a pressure of 2 kgf/ ^cm2 in a chamber at a temperature of 40°C and a relative humidity of 45% and left for 3 days to check the state of fusion between the fibers. 10 experts visually observed the results and set a standard with 10 points if no fusion occurred and 0 points if all fusion occurred.After evaluating from 0 to 10 points, the average value was calculated. did. As a result, if the average value is 9.0 or more, it is excellent (◎), if it is 7.0 or more and less than 9.0, it is excellent (○), and if it is 5.0 or more and less than 7.0, it is fair (△). ), less than 5.0 was marked as bad (x).

5. Spinning workability The spinning workability was determined based on the results of the spinning process for core-sheath type composite fibers spun with the same content in Examples and Comparative Examples. Using a drip sensor, count the number of clumps formed when the strands are fused together irregularly, and use the drip number in Preparation Example 1 as 100 to set a standard for the remaining preparations. The number of drips generated in the examples and comparative preparation examples is expressed as a relative percentage.

6. Evaluation of dyeing rate After carrying out a dyeing process at 90°C for 60 minutes at a bath ratio of 1:50 using a dye solution containing 2% by weight of blue dye based on the weight of the core-sheath composite fiber. After measuring the spectral reflectance in the visible range (360 to 740 nm, 10 nm intervals) of the dyed composite fiber using a color measurement system manufactured by KURABO in Japan, it was determined as an index of dyeing amount based on the CIE 1976 standard. A certain Total K/S value was calculated to evaluate the color yield of the dye.

7. Adhesive strength Each of the three types of fiber aggregates was formed into a test piece measuring 100 mm x 20 mm x 10 mm in width, length, and thickness, and bonded using a UTM (universal testing machine) based on the KS M ISO 36 method. The strength was measured.

On the other hand, when the shape was deformed due to excessive shrinkage during heat treatment, the adhesive strength was not evaluated and the evaluation was made as "shape deformation."

8. Soft feel A group of 10 industry experts conducted a sensory test on the fiber aggregates manufactured by heat-treating them at a temperature of 140°C among the three types of fiber aggregates, and the evaluation results were as follows: If the above was judged to be soft, it was classified as excellent (◎), 6 to 7 people as good (○), 5 to 4 people as fair (△), and less than 4 people as poor (x).

As can be confirmed through Tables 1 to 3,
In the comparative examples, either the drying time is significantly prolonged (Comparative Examples 1 to 3), the spinning workability is significantly poor (Comparative Examples 2 and 3), or the single fiber storage stability is extremely poor. (Comparative Example 2, Comparative Example 3), and the shape was deformed in the temperature-dependent adhesive strength evaluation (Comparative Example 4), confirming that it is not possible to satisfy all physical properties at the same time. It can be confirmed that the example exhibits all physical properties at an excellent level.

On the other hand, in Examples, Example 13, which contained a higher content of the compound represented by Chemical Formula 2 than the compound represented by Chemical Formula 1, was found to have a higher adhesive strength evaluation at different temperatures than other Examples. It can be confirmed that the material is deformed and is not suitable for achieving the desired physical properties.

<Examples 15 to 29>
The copolyester was produced in the same manner as in Example 1, but the composition ratio of the monomers for producing the copolyester was changed as shown in Table 4 below, and this was used to produce the copolyester shown in Table 4 below. A fiber aggregate like this was manufactured. At this time, the heat treatment temperature for manufacturing the fiber aggregate was 140°C.

<Comparative example 5>
The copolyester was produced in the same manner as in Example 1, but the composition ratio of the monomers for producing the copolyester was changed as shown in Table 4 below, and this was used to produce the copolyester shown in Table 4 below. A fiber aggregate like this was produced. At this time, the heat treatment temperature for manufacturing the fiber aggregate was 140°C.

<Experiment example 2>
The following physical properties were evaluated for the thermoadhesive fibers embodied by Examples 15 to 29 and Comparative Example 5, the embodied fiber aggregates, or the copolyester chips that were intermediates during the production of the fiber aggregates. The results are shown in Table 4 below.

1. Intrinsic viscosity Intrinsic viscosity was measured using the same method as in Experimental Example 1.

2. Volatile Organic Compounds (VOCs) Content Measured by US EPA TO-14 Method.

3. Soft tactile sensation The tactile sensation was evaluated using the same method as in Experimental Example 1.

As can be confirmed through Table 4,
In the case of Examples 15 to 29, the amount of VOCs generated by the heat-adhesive fibers is smaller than that of Comparative Example 5, and it can be seen that the fiber aggregates equipped with the same are highly suitable for automobile interior materials.

<Examples 30 to 33>
A fiber assembly was manufactured in the same manner as in Example 21, but the mixing ratio of the heat-adhesive fiber and the PET support fiber was changed as shown in Table 5 below. At this time, the heat treatment temperature for manufacturing the fiber aggregate was 165°C.

<Comparative example 6>
A fiber assembly was manufactured in the same manner as in Example 30, but the composition of the heat-adhesive fibers and the mixing ratio of PET fibers were changed as shown in Table 5 below.

<Comparative Examples 7-8>
A fiber assembly was manufactured in the same manner as in Example 21, but the composition of the heat-adhesive fibers and the mixing ratio of PET fibers were changed as shown in Table 5 below. At this time, the heat treatment temperature for manufacturing the fiber aggregate was 165°C.

<Experiment example 3>
The following physical properties were evaluated for the fiber aggregates according to Examples 30 to 33 and Comparative Examples 6 to 8, and are shown in Table 5 below.

1. Initial openability Lab. After checking the initial degree of cotton opening during web production using a carding machine, an internal expert evaluates the relative degree of cotton opening, and the evaluation results are rated as very excellent (◎), excellent (○), and average. (Δ) and poor (x).

2. Carding property Lab. Internal experts evaluated the workability of web production using a carding machine by comparing the relative workability, and the evaluation results were ranked as excellent (◎), excellent (○), average (△), It was evaluated as poor (x).

3. Adhesive Strength As in Experimental Example 1, adhesive strength was measured using a universal testing machine (UTM) based on the KSM ISO 36 method.

4. Processability When evaluating nonwoven fabrics, internal experts compare and evaluate the relative workability of process workability items such as initial opening properties, carding properties, and processing speed. Evaluation was made as excellent (◎), excellent (○), fair (△), and poor (x).

5. Average sound absorption coefficient and frequency-specific sound absorption coefficient Measured using KS F 2805.

6. Repulsion elasticity modulus An iron ball was dropped onto a test piece from a certain height, and the height of rebound was measured (JIS K-6301, unit: %). The test piece was made into a regular square with a side length of 50 mm or more and a thickness of 50 mm or more. A steel ball weighing 16 g and a diameter of 16 mm was dropped onto the test piece at a height of 500 mm to measure the maximum rebound height. After that, the repulsion values were measured at least three times consecutively within 1 minute for each of the three test pieces, and the median value was taken as the repulsion elasticity rate (%).

As can be confirmed through Table 5,
The fiber aggregates according to the examples of the present invention are superior to the fiber aggregates according to comparative examples in initial opening properties, carding properties, adhesive strength, rebound modulus, and processability, and are also excellent in sound absorption coefficient. It can be confirmed that it is suitable for automotive interior materials.

Although one embodiment of the present invention has been described, the spirit of the present invention is not limited to the embodiment presented herein, and those skilled in the art who understand the spirit of the present invention will be able to understand the spirit within the scope of the same spirit. However, other embodiments can be easily proposed by adding, changing, deleting, adding, etc. components, and these are also included within the scope of the present invention.

Claims (12)

An acid component containing terephthalic acid, and an esterified compound containing ethylene glycol and a compound represented by the following chemical formula 1 and a compound represented by the following chemical formula 2 , but not containing diethylene glycol, are polycondensed. It is characterized by comprising a thermally adhesive fiber containing polyester and a polyester support fiber having a melting point higher than 250° C., wherein the thermally adhesive fiber and the supporting fiber are contained in a weight ratio of 20:80 to 50:50. A fiber aggregate for automobile interior materials.

The automobile interior according to claim 1, wherein the total content of the compound represented by the chemical formula 1 and the compound represented by the chemical formula 2 is 30 to 45 mol% of the diol component. Fiber aggregate for materials. The fiber aggregate for automobile interior materials according to claim 1, wherein the content of the compound represented by the chemical formula 1 in the diol component is greater than the content of the compound represented by the chemical formula 2. The diol component is characterized in that the compound represented by the chemical formula 1 is contained in an amount of 20 to 40 mol%, and the compound represented by the chemical formula 2 is contained in an amount of 0.8 to 10 mol%. 1. The fiber aggregate for automobile interior materials according to item 1. The fiber assembly for automobile interior materials according to claim 1, wherein the heat-adhesive fibers and the supporting fibers are contained in a weight ratio of 30:70 to 40:60. The diol component is characterized in that the compound represented by the chemical formula 1 is contained in an amount of 30 to 40 mol%, and the compound represented by the chemical formula 2 is contained in an amount of 0.8 to 6 mol%. 1. The fiber aggregate for automobile interior materials according to item 1. The fiber aggregate for automobile interior materials according to claim 1, characterized in that the average sound absorption coefficient is 0.35 or more within a frequency range of 400 to 2000 Hz. The fiber aggregate for automobile interior materials according to claim 1, wherein the heat-adhesive fiber has a VOCs emission amount of 2600 ppb or less as measured based on the US EPA TO-14 method. The fiber aggregate for automobile interior materials according to claim 1, characterized in that the adhesive strength based on KSM ISO 36 is 130 to 200 N/25 mm. The fiber aggregate for automobile interior materials according to claim 1, characterized in that the sound absorption coefficient based on KS F 2805 satisfies the following conditions.
(1) Sound absorption coefficient of 0.53 or more at a frequency of 1000Hz (2) Sound absorption coefficient of 0.73 or more at a frequency of 2000Hz The fiber aggregate for automobile interior materials according to claim 1, characterized in that the sound absorption coefficient based on KS F 2805 satisfies the following conditions.
(3) Sound absorption coefficient of 0.83 or more at a frequency of 3000Hz (4) Sound absorption coefficient of 0.92 or more at a frequency of 4000Hz 1. An automobile interior material comprising the fiber aggregate for automobile interior material according to any one of claims 1 to 1 .