WO2021071251A1 - Thermally adhesive fiber and fiber aggregate comprising same for motor vehicle interior material - Google Patents

Abstract

The present invention relates to a thermally adhesive fiber and, more specifically, to a thermally adhesive fiber, a fiber aggregate for an automobile interior material, and a motor vehicle interior material comprising same, wherein the thermally adhesive fiber exhibits far superior tactility, acoustic absorptivity, adhesive strength, flame retardancy, and processability, minimizes a temporal change due to excellent heat resistance, and remarkably reduces release of VOCs and thus is particularly suitable for a motor vehicle in which a sealed environment is implemented.

Description

Heat-adhesive fiber and fiber assembly for automobile interior materials containing the same

The present invention relates to a heat-adhesive fiber, and more particularly, it has excellent touch, sound absorption, adhesive strength, flame retardancy and workability, and its excellent heat resistance minimizes change over time, and the emission of VOCs is remarkably reduced to realize a sealed environment. It relates to a heat-adhesive fiber particularly suitable for automobiles, a fiber assembly for automobile interior materials, and automotive interior materials including the same.

In general, synthetic fibers have a high melting point and are often limited in use. In particular, in the case of bonding applications such as fibers, in the case of use as a wick or as an adhesive that is inserted between tape-like fabrics and bonded by pressure, the fiber fabric itself may be deteriorated by heating, and special equipment such as high-frequency sewing machine must be used. Because of the inconvenience of doing so, it is desired to easily adhere by a common simple heating press without using such special equipment.

Conventional low-melt polyester fibers have been widely used for the purpose of adhering different types of fibers in mutual fiber structures used in the manufacture of mattresses, interior materials for automobiles, or various nonwoven fabric patting applications.

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 Korean Patent No. 10-1216690 The issue discloses a low melting point polyester fiber including isophthalic acid and diethylene glycol to improve adhesion.

However, the conventional low-melting polyester fiber as described above may have a certain level of spinnability and adhesiveness, but there is a problem in that a rigid interior material for automobiles is realized after heat bonding due to the ring structure of a rigid modifier.

In addition, as the development progresses toward a low melting point or low glass transition temperature for the development of binder properties, the heat resistance of the embodied polyester deteriorates, resulting in significant changes with time even under storage conditions exceeding 40°C in summer. There is a problem in that the storage stability is also markedly deteriorated due to the occurrence of bonding between the polyester fibers occurring in the material. In particular, the indoor temperature of a car parked outdoors in summer may rise to 60°C or higher, and a change over time of the implemented interior material may also be a problem when a polyester fiber having poor heat resistance is used under such conditions.

On the other hand, automobiles are generally operated in a closed state with the outside, and in particular, there is a trend of increasing operation in a more sealed state due to the influence of recent fine dust. Accordingly, the quality of the air in the interior space of the vehicle is important, and the problem of emission of volatile organic compounds (VOCs) from interior materials mounted in the interior space has been reported, and the problem of harming the health of the occupants due to the released volatile organic compounds is emerging. Actually.

Accordingly, there is an urgent need to develop interior materials for automobiles in which tactile feel, sound absorption, adhesive strength and workability are improved, changes over time are minimized, and emission of VOCs is significantly reduced.

The present invention has been devised in consideration of the above points, and has excellent touch, sound absorption, flame retardancy, adhesive strength and workability, minimizes change over time with excellent heat resistance, and significantly reduces the emission of VOCs, thereby realizing a sealed environment. As it is particularly suitable for automobiles, an object of the present invention is to provide a fiber assembly for automobile interior materials such as seatbacks and automobile interior materials including the same.

In order to solve the above problems, the present invention includes a core containing a polyester-based component and a phosphorus-based flame retardant, and an acidic component containing terephthalic acid, and ethylene glycol and a compound represented by the following formula (1) and a compound represented by formula (2). Including a copolyester in which an esterified compound reacted with a diol component is polycondensed, and a sheath surrounding the core; including, and thermal bonding with an acetaldehyde (AA) generation amount of 2400 ppb or less according to the MS 300-55 method Provides sex fibers.

[Formula 1]

[Formula 2]

According to an embodiment of the present invention, the total amount of the compound represented by Formula 1 and the compound represented by Formula 2 may be included in 30 to 45 mol% of the diol component.

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

In addition, the diol component may not contain diethylene glycol.

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

In addition, of the diol component, the compound represented by Formula 1 may be contained in an amount of 1 to 40 mol%, and the compound represented by Formula 2 may be included in an amount of 0.8 to 20 mol%, more preferably, the diol component represented by Formula 1 The compound represented is 20 to 40 mol%, the compound represented by Formula 2 is 0.8 to 10 mol%, more preferably the compound represented by Formula 1 is 30 to 40 mol%, the compound represented by Formula 2 is It may be included in 0.8 ~ 6 mol%.

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

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

In addition, the core portion may further include a phosphorus-based flame retardant represented by Formula 3 below, based on a phosphorus content of 5500ppm to 6500ppm.

[Formula 3]

At this time, in Formula 3, R is an alkylene group having 1 to 5 carbon atoms, n is an integer of 1 to 20, and m is an integer of 1 to 80.

In addition, the sheath may further include a phosphorus-based flame retardant represented by Chemical Formula 3 above.

In addition, the amount of acetaldehyde (AA) generated may be 1950 ppb or less, more preferably 1600 ppb or less.

In addition, the present invention provides a fiber assembly for automobile interiors comprising a heat-adhesive fiber according to the present invention and a polyester-based support fiber having a melting point higher than 250°C.

According to an embodiment of the present invention, the heat-adhesive fiber and the support fiber may be included in a weight ratio of 70:30 to 30:70.

In addition, as the following conditions (1) and (2), (1) a value according to Equation 1 below may be 27 to 55, and (2) high temperature sag may be 45 mm or less, more preferably 20 mm or less.

[Equation 1]

In Equation 1, D and T are the carbonization distance and residual time measured by the MS 300-08 method, respectively, and the specimen is a heat-adhesive fiber (fiber length 51 mm, fineness 4.0de) and polyethylene terephthalate (PET ) Short fibers (fiber length 51㎜, fineness 7.0de) are blended and opened at a weight ratio of 5:5, and then heat-treated at 180℃ for 15 minutes to achieve a basis weight of 330g/m².

In addition, the present invention provides a vehicle interior material comprising the fiber assembly for automotive interior material according to the present invention.

The fiber assembly for automobile interior materials according to the present invention is excellent in touch, sound absorption, adhesive strength, flame retardancy, and workability. In addition, as the change over time is minimized due to its excellent heat resistance, it is very suitable for automotive interior materials in which a high temperature indoor temperature is formed during outdoor parking in summer. Furthermore, since the emission of VOCs is significantly reduced, it can be widely applied in related fields as it is very suitable for automobile interior materials that increase operation in an enclosed environment.

1 is a schematic cross-sectional view of a heat-adhesive fiber included in an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

Referring to FIG. 1, the heat-adhesive fiber 10 according to the present invention includes a core 11 and a sheath 12 surrounding the core 11.

First of all, the chobu 12 is a reaction of an acidic component including terephthalic acid, and a diol component including a compound represented by the following formula (1) and a compound represented by the formula (2) with ethylene glycol. It includes a copolyester in which an esterified compound is polycondensed.

[Formula 1]

[Formula 2]

First, the acidic component includes terephthalic acid, and in addition to terephthalic acid, an aromatic polyhydric carboxylic acid having 6 to 14 carbon atoms, or an aliphatic polyhydric carboxylic acid having 2 to 14 carbon atoms and/or a metal sulfonic acid metal salt may be further included.

The aromatic polyhydric carboxylic acid having 6 to 14 carbon atoms is an acid component used for the production of polyester, and known ones may be used without limitation, but preferably any selected from the group consisting of dimethyl terephthalate, isophthalic acid and dimethyl isophthalate. It may be one or more, more preferably isophthalic acid in terms of reaction stability with terephthalic acid, ease of handling, and economy.

In addition, the aliphatic polyhydric carboxylic acid having 2 to 14 carbon atoms may be used without limitation, as an acid component used for the production of polyester, but non-limiting examples thereof include oxalic acid, malonic acid, succinic acid, glutaric acid, and It may be any one or more selected from the group consisting of acid, adipic acid, suberic acid, citric acid, pimeric acid, azelaic acid, sebacic acid, nonanoic acid, decanoic acid, dodecanoic acid and hexanodecanoic acid.

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

On the other hand, other components that may be provided in addition to terephthalic acid as the acidic component may reduce the heat resistance of the copolyester, and thus are preferably not included. In particular, when an acidic component such as isophthalic acid or dimethyl isophthalate is further included, the content of VOCs generated in the polycondensation process of the copolyester, for example, the content of acetaldehyde, may increase, while the melting point of the copolyester. Since silver is further reduced and it is difficult to vaporize and remove acetaldehyde generated in the polymerization process through a subsequent process through heat treatment, etc., the content of acetaldehyde in the resulting fiber may be high. Therefore, if isophthalic acid is further included, it may be provided in an amount of 1 to 10 mol% based on the acid content, and if it is provided in excess of 10 mol%, there is a concern that the acetaldehyde content may be excessively increased, and the heat-adhesive fiber implemented by this May not be suitable for automotive interior applications.

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

[Formula 1]

[Formula 2]

First, the compound represented by Formula 1 may lower the crystallinity and glass transition temperature of the prepared copolyester to exhibit excellent thermal bonding performance. In addition, it is possible to dye the dyeing process under normal pressure conditions in the dyeing process after it is manufactured in a fibrous form, thereby facilitating the dyeing process, and improving the washing fastness due to excellent dyeing properties, and improving the texture of the fiber aggregate. Preferably, of the diol component, the compound represented by Formula 1 may be included in an amount of preferably 20 to 40 mol%, more preferably 30 to 40 mol%. In particular, when 20 mol% or more of the compound represented by Formula 1 is provided, the copolyester implemented with the compound represented by Formula 2 to be described later may further increase and improve the thermal adhesive properties at low temperatures. The drying time can be remarkably shortened when manufactured into chips, and there is an advantage that an increased effect can be expressed in reducing the content of VOCs emitted from the heat-adhesive fiber.

If the compound represented by Chemical Formula 1 is contained in an amount of less than 20 mol% based on the diol component, spinnability is excellent, but there is a concern that the adhesive temperature may be increased or the thermal bonding properties may be deteriorated, and the intended use may be limited. In addition, there is a concern that the content of VOCs emitted from the implemented heat-adhesive fiber may increase. In addition, if the compound represented by Formula 1 is provided in excess of 40 mol%, it may cause problems that are difficult to commercialize due to poor spinning to the heat-adhesive fiber. There is a concern.

The compound represented by Formula 2 further improves the thermal adhesive properties of the copolyester prepared with the compound represented by Formula 1, while preventing the glass transition temperature of the compound represented by Formula 1 from significantly lowering, thereby providing excellent thermal performance. Let the character manifest. For example, despite the storage temperature of 40℃ or higher and the interior temperature of a car that rises to 60℃ or higher in summer, it can be used as an exterior material for parts where high-temperature environments such as engine rooms are created, and improve storage stability. I can. Regarding heat adhesion, the compound represented by Formula 2 exhibits appropriate shrinkage properties in the heat-adhesive fiber using copolyester, which is realized by being mixed with the compound represented by Formula 1, and due to the development of these properties, By further increasing the point adhesion, it is possible to exhibit more enhanced thermal adhesion properties.

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

If the compound represented by Formula 2 is contained in an amount of less than 0.8 mol% based on the diol component, it is difficult to improve the desired heat resistance, so that the storage stability is not good, and there is a concern that the change over time may be very large. In addition, there is a concern that the content of VOCs emitted from the implemented heat-adhesive fiber may increase.

In addition, if the compound represented by Chemical Formula 2 is contained in an amount exceeding 10 mol%, considering that it is used together with the compound represented by Chemical Formula 1, there may be a problem that is difficult to commercialize due to poor spinnability into the heat-adhesive fiber. . In addition, in some cases, when isophthalic acid is additionally included as an acidic component, the crystallinity is sufficiently lowered to improve adhesion, and when the amount of isophthalic acid to be added increases, crystallinity is rather increased at the desired temperature. There is a concern that the object of the present invention may not be achieved, such as the excellent thermal adhesive properties of may be significantly deteriorated. In addition, when implemented in a fibrous form, the shrinkage is remarkably large, which makes it difficult to process 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 Formula 1 and the compound represented by Formula 2 is preferably contained in 30 to 45 mol% of the diol component, more preferably 33 to It may be contained in 41 mol%. If they contain less than 30 mol%, the crystallinity of the copolyester increases, resulting in a high melting point or difficulty in implementing the softening point at a low temperature, resulting in a remarkably high thermal bonding temperature, and excellent thermal bonding properties at low temperatures. It may not be. In addition, there is a concern that the content of VOCs emitted from the implemented heat-adhesive fiber may increase.

In addition, if the compound represented by Chemical Formula 2 is contained in excess of 45 mol%, there is a concern that polymerization reactivity and radioactivity may be significantly lowered, and the crystallinity of the prepared copolyester is rather increased, resulting in high thermal adhesion at a desired temperature. It can be difficult to express the trait.

In this case, in the diol component, the compound represented by Formula 1 may be included in a larger content (mol%) than the compound represented by Formula 2. If the compound represented by Formula 1 is included in an amount less than or equal to the compound represented by Formula 2, it is difficult to express the desired heat-adhesive properties, and it may be limited in the use of the product to be developed as it must be adhered at high temperatures. In addition, there is a concern that it may be difficult to process or utilize a product that develops due to the expression of excessive shrinkage characteristics, for example, as an automobile interior material.

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 types of diol components may be known diol components used in the production of polyester, so the present invention is not particularly limited thereto, but as a non-limiting example thereof, an aliphatic diol component having 2 to 14 carbon atoms may be used. , Specifically, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, propylene glycol, trimethyl glycol, tetramekylene glycol, pentamethyl glycol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol , Nonamethylene glycol, decamethylene glycol, undecamethylene glycol, dodecamethylene glycol, and may be any one or more selected from the group consisting of tridecamethylene glycol.

However, it is preferable not to further include the other types of diol components in order to combine heat resistance with the desired level of heat bonding properties, and in particular, diethylene glycol may not be included in the diol component. If diethylene glycol is included in the diol component, it may cause a rapid decrease in the glass transition temperature, so that even when the compound represented by Formula 2 is provided, the desired level of heat resistance may not be achieved. In addition, there is a concern that the content of VOCs released during use will increase significantly. On the other hand, the meaning that the diol component does not contain diethylene glycol means that diethylene glycol is not intentionally added as a monomer for the production of copolyester, and the esterification reaction of the acid component and the diol component, poly/condensation It does not mean that it does not include diethylene glycol, which occurs as a by-product in the reaction. Since diethylene glycol may occur naturally as a by-product, according to an embodiment of the present invention, diethylene glycol generated as a by-product may be included in the sheath formed including copolyester, and the content of diethylene glycol contained is copolyester. It may be less than 4% by weight based on the ultra-part weight consisting of chips or copolyester alone. On the other hand, if the content of diethylene glycol generated as a by-product exceeds an appropriate level, it increases the pack pressure during spinning into fibers, causes frequent thread trimming, and thus spinnability may be significantly lowered, and the content of released VOCs, especially acetaldehyde. There is a fear that the amount of emission will increase significantly.

The above-described acidic component and diol component may be prepared into copolyester through esterification and polycondensation using known synthetic conditions in the polyester synthesis field. At this time, the acid component and the diol component may be added to react in a molar ratio of 1: 1.0 to 5.0, preferably 1: 1.0 to 2.0, but is not limited thereto. If the molar ratio is less than 1 times the amount of the diol component based on the acid component, the acidity may be excessively high during polymerization, thereby promoting side reactions.If the molar ratio exceeds 5 times the amount of the diol component based on the acid component, the degree of polymerization may not increase. have.

On the other hand, the acidic component and diol component are mixed at one time in an appropriate molar ratio as described above, and then esterified and polycondensed to form a copolyester, or between ethylene glycol and a compound represented by Formula 1 among the acid component and diol component. During the esterification reaction, the compound represented by Formula 2 may be added to form a copolyester through esterification and polycondensation, and the present invention is not particularly limited thereto.

In the esterification reaction, a catalyst may be further included. The catalyst may be a catalyst typically used in the production of polyester, and as a non-limiting example thereof, it may be prepared under a metal acetate catalyst.

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

In addition, the polycondensation reaction may be performed under a temperature of 250 to 300°C and a pressure of 0.3 to 1.0 Torr, and if the above conditions are not satisfied, there may be problems such as delay in reaction time, decrease in polymerization degree, and induce thermal decomposition. . In addition, the polycondensation reaction may vary in reaction time depending on reaction conditions, but may be performed for 150 to 240 minutes, for example.

In this case, a catalyst may be further included during the polycondensation reaction. The catalyst may be used without limitation in the case of a known catalyst used for producing a polyester resin. However, preferably, it may be a titanium-based polymerization catalyst, and more specifically, may be a titanium-based polymerization catalyst represented by the following formula (4).

[Formula 4]

The titanium-based polymerization catalyst represented by Chemical Formula 4 is stable even in the presence of water molecules. For this reason, even if water is added prior to the esterification reaction in which a large amount of water is added, the esterification reaction and polycondensation reaction may proceed within a shorter time than the conventional one, and coloration due to yellowing may be suppressed. . The catalyst may be included so as to be 5 to 40 ppm in terms of titanium atoms in the total weight of the obtained copolyester, through which the thermal stability or color tone of the copolyester becomes better, and thus it is preferable. If it is provided with less than 5 ppm in terms of titanium atoms, it may be difficult to adequately promote the esterification reaction, and if it is provided in excess of 40 ppm, reactivity may be promoted, but there may be a problem in that coloration occurs.

Meanwhile, a heat stabilizer may be further included during the polycondensation reaction. The thermal stabilizer is for preventing discoloration of color through thermal decomposition at high temperature, and a phosphorus compound may be used. Phosphoric acids such as phosphoric acid, monomethyl phosphoric acid, trimethyl phosphoric acid, and triethyl phosphoric acid and derivatives thereof are preferably used as the phosphoric compound, and among them, trimethyl phosphoric acid or triethyl phosphoric acid is particularly preferable because of its excellent effect. The amount of the phosphorus compound is preferably 10 to 30 ppm in terms of phosphorus atoms based on the total weight of the final copolyester. If the phosphorus-based thermal stabilizer is used in less than 10 ppm, it is difficult to prevent high-temperature thermal decomposition and the copolyester may be discolored. If it exceeds 30 ppm, it may be disadvantageous in terms of manufacturing cost, and the thermal stabilizer inhibits catalytic activity during polycondensation reaction. There may be a problem in that the reaction delay phenomenon occurs.

In addition, the copolyester may further include a complementary colorant. The complementary colorant is for color tone adjustment to make the color of the dye dyed stronger and better in the dyeing process that proceeds after being spun into the fiber, and may be added known in the textile field, and as a non-limiting example Wear dyes, pigments, vat dyes, disperse dyes, organic pigments, etc. However, preferably, a mixture of blue and red dyes may be used. This is because cobalt compounds, which are generally used as complementary colors, are not preferable because they are harmful to the human body. In addition, when a mixture of blue and red dyes is used, there is an advantage in that the color tone can be finely controlled. Examples of the blue dye include solvent blue 104, solvent blue 122, and solvent blue 45, and examples of the red dye include solvent red 111, solvent red 179, and solvent red 195. In addition, the blue dye and the red dye may be mixed in a weight ratio of 1: 1.0 to 3.0, which is advantageous in expressing a remarkable effect on a desired fine color tone control.

The complementary colorant may be 1 to 10 ppm based on the total weight of the copolyester.If it is provided with less than 1 ppm, it may be difficult to achieve the desired level of complementary color characteristics, and if it exceeds 10 ppm, the L value is reduced. Therefore, there may be a problem in that transparency is deteriorated and a dark color appears.

The copolyester prepared through the above-described 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, it may not be easy to form a cross section after being spun into a fiber, and if the intrinsic viscosity is more than 0.8 dl/g, there is a concern that the spinnability is deteriorated due to a high pack pressure.

In addition, the copolyester may have a glass transition temperature of 60 to 75°C, which may be more advantageous in achieving the object of the present invention. If the glass transition temperature is less than 60℃, the heat-adhesive fiber or the product including the copolyester has a large change with time even under a temperature condition exceeding 40℃, such as in summer. When considering the indoor temperature of a vehicle, the change over time can be significantly increased. In addition, when the heat-adhesive fiber is produced, the occurrence of bonds between copolyester chips increases, which may cause spinning defects. Furthermore, there is a concern that the shrinkage properties are excessively expressed after being implemented with fibers or the like, and the bonding properties are rather deteriorated. In addition, due to the limitation of heat treatment required for a drying process after chip formation or a post-processing process after spinning into fibers, there may be a problem in that the time required for the process is prolonged or the process cannot be performed smoothly.

In addition, if the glass transition temperature exceeds 75°C, there is a concern that the thermal bonding characteristics may be significantly deteriorated, and the performing temperature of the bonding process may be limited to a high temperature.

Meanwhile, the above-described sheath 12 may further include a phosphorus-based flame retardant. The phosphorus-based flame retardant may be used without limitation in the case of a known phosphorus-based flame retardant provided in the fiber. Preferably, the phosphorus-based flame retardant may include a compound represented by Formula 3 to be described later. Alternatively, when the phosphorus-based flame retardant is included in the above-described sheath 12, the melting point of the sheath is increased, and thus there is a concern that the adhesive strength may decrease. In particular, in the case of the compound represented by Formula 2, the melting point may be increased due to the inclusion of a phosphorus-based flame retardant compared to other types of modified monomers, and thus there is a concern that the adhesive strength may decrease. Accordingly, according to another embodiment of the present invention, the sheath 12 may not contain a phosphorus-based flame retardant. Here, that the phosphorus-based flame retardant is not included means that the phosphorus-based flame retardant is not included as a component bonded to the main chain or side chain in the copolyester copolymer provided in the sheath and/or included in the sheath together with the copolyester.

On the other hand, when the compound represented by Chemical Formula 3 to be described later is included in the chobu 12, it may be provided in an amount of 5500 ppm to 6500 ppm based on a phosphorus content. If the compound is provided with a phosphorus content of less than 5500 ppm, it may be difficult to implement sufficient flame retardancy to a desired level. In addition, if the compound is provided in excess of 6500 ppm based on phosphorus content, the degree of improvement in flame retardancy may be insignificant, whereas spinnability decreases, and due to an increase in melting point, mechanical properties such as a decrease in adhesive strength and strength of heat-adhesive fibers are remarkable. There is a risk of deterioration.

Next, the core 11 includes a polyester-based component. The polyester-based component is not limited in the case of a polyester-based component having a melting point or softening point higher than the melting point or softening point of the copolyester provided in the above-described sheath 12, and may be polyethylene terephthalate as an example.

In addition, the core 11 may further include a phosphorus-based flame retardant. The phosphorus-based flame retardant may be used without limitation in the case of a known phosphorus-based flame retardant mixed with a polymer compound to improve flame retardant properties. Preferably, the phosphorus-based flame retardant may include a compound represented by the following formula (3).

[Formula 3]

At this time, in Formula 3, R is an alkylene group having 1 to 5 carbon atoms, and preferably an alkylene group having 2 to 4 carbon atoms. In addition, n is an integer of 1 to 20, preferably an integer of 5 to 10. In addition, m is an integer of 1 to 80, preferably an integer of 20 to 40.

The compound represented by Chemical Formula 3 may be provided in the core 11 in an amount of 5500ppm to 6500ppm based on the phosphorus content. If the compound is provided with a phosphorus content of less than 5500 ppm, it may be difficult to implement sufficient flame retardancy to a desired level. In addition, if the compound is provided in excess of 6500 ppm based on the phosphorus content, the degree of improvement in flame retardancy may be insignificant, while spinnability decreases, and mechanical properties such as the strength of the heat-adhesive fiber may be remarkably deteriorated.

The heat-adhesive fiber may be, for example, a composite spinning of the core and the sheath at a weight ratio of 8:2 to 2:8, but is not limited thereto, and may be spun by appropriately adjusting the ratio according to the purpose. The present invention can be performed through the conditions, equipment and processes known in the art, or by appropriately modifying the spinning conditions for the heat-adhesive fiber, the spinning device, and the cooling and stretching of the composite fiber after spinning. Is not particularly limited to this. In addition, as an example, the heat-adhesive fiber may be spun at a spinning temperature of 270 to 290°C, and may be stretched 2.5 to 4.0 times after spinning.

In the heat-adhesive fiber according to the present invention, the amount of acetaldehyde (AA) generated according to the MS 300-55 method is 2400 ppb or less, and through this, the amount of harmful components to the human body in a sealed environment such as the interior of a vehicle is remarkably small. It can be very useful as, and has the advantage of reducing the odor of interior materials. Preferably, the generation amount of acetaldehyde (AA) may be 1950 ppb or less, more preferably, the generation amount of acetaldehyde (AA) may be 1600 ppb or less, and may be more suitable as an automobile interior material.

The heat-adhesive fiber according to an embodiment of the present invention embodying the above-described manufacturing method implements a fiber assembly for automobile interior materials together with a polyester-based support fiber.

The heat-adhesive fiber performs a role of attaching the polyester-based support fibers through heat fusion, and itself may be used as a fiber that secures the shape and mechanical strength of the fiber aggregate.

The heat-adhesive fiber may have a fineness or a fiber length appropriately selected in consideration of the physical properties of the fiber aggregate to be implemented. For example, the fineness may be 1 to 15 denier, and the fiber length may be 1 to 100 mm, for example.

In addition, the support fiber is implemented by including a polyester-based component for compatibility with the heat-adhesive fiber, and serves to ensure mechanical strength, shape maintenance, and heat resistance of the fiber assembly. To this end, the polyester-based component may be a component having a melting point higher than 250°C, and through this, it may be more advantageous to achieve the object of the present invention.

The support fiber may have a fineness of 1 to 15 denier, and the fiber length may be 1 to 100 mm, but is not limited thereto.

In addition, the support fiber may be used without limitation in the case of a known polyester-based component having a melting point exceeding 250° C., and for example, may be polyethylene terephthalate.

The above-described heat-adhesive fiber and support fiber may form a fiber aggregate in a weight ratio of 30:70 to 70:30. If the supporting fiber is provided with a greater weight than the heat-adhesive fiber outside the weight ratio, the bonding strength of the fiber assembly may decrease. In addition, when the supporting fiber is provided with a weight less than the heat-adhesive fiber outside the weight ratio, the sound absorption rate, touch, and shape stability of the fiber assembly are significantly reduced, and there is a concern that workability such as initial opening property and carding property may be significantly reduced. have.

The fiber aggregate including the heat-adhesive fiber and the supporting fiber may be a known fabric type, for example, a woven fabric, a knitted fabric, or a non-woven fabric, and for example, may be a non-woven fabric without directionality based on the fiber length direction. The nonwoven fabric may be manufactured through a known dry or wet nonwoven manufacturing method, and the present invention is not particularly limited thereto.

As an example, the heat-adhesive fiber and the supporting fiber may be made of short fibers having a predetermined length, and then the short fibers may be honed and opened, and then heat treated to form a fiber aggregate. The heat treatment may be 100 to 180° C., more preferably 120 to 180° C., through which more improved adhesive properties may be expressed.

The fiber assembly for automobile interior material according to an embodiment of the present invention may satisfy the following conditions (1) and (2).

As the condition (1), a value according to Equation 1 below may be 27 to 55, more preferably 29 to 40. As the fiber assembly satisfies the value of Equation 1 as above, it exhibits remarkably excellent flame retardant properties, and is very advantageous in that it suppresses the spread of fire. If the value according to Equation 1 is less than 27, there may be a problem in that carbonization continues even after the flame is extinguished or the time required for the flame to extinguish is prolonged. In addition, when the value of Equation 1 exceeds 55, there may be a problem in that the initial bullet area of the fire is wide, that is, the fire spreads quickly. In addition, the strength of the heat-adhesive fibers contained in such a fiber aggregate is low, and there is a concern that the heat-adhesive properties are also deteriorated.

[Equation 1]

On the other hand, in Equation 1, D and T are the carbonization distance and residual time measured by the MS 300-08 method, respectively, and the specimen is a heat-adhesive fiber (fiber length 51 mm, fineness 4.0 de) and polyethylene terephthalate. (PET) Single fiber (fiber length 51㎜, fineness 7.0de) was mixed and opened at a weight ratio of 5:5, then heat-treated at 140℃ for 15 minutes, and measured using a fiber aggregate with a basis weight of 330g/m². It is the result.

Next, as condition (2), the high-temperature sag measured by the following measurement method may be 45 mm, more preferably 20 mm or less, and through this, even when used close to a high-temperature heating source, deformation of the shape can be minimized. In addition, there is an advantage of preventing shape deformation even in a high temperature environment in summer. At this time, the high-temperature sagging is performed by blending and opening the heat-adhesive fiber (fiber length 51 mm, fineness 4.0de) and polyethylene terephthalate (PET) short fiber (fiber length 51 mm, fineness 7.0de) in a weight ratio of 5:5. After heat treatment at 180°C for 15 minutes, a fiber aggregate specimen of 100mm×20mm×10mm thickness, each 100mm×20mm×10mm, manufactured with a basis weight of 330g/m², was exposed in an environment at 90°C for 2 hours, and then in the longitudinal direction of the sample. After fixing both ends, the sagging width of the sagging part was measured. At this time, the sag width was measured based on the lower surfaces of both ends, and the maximum value was taken as the high temperature sag value.

On the other hand, the above-described fiber assembly for automobile interior material may be implemented as a vehicle interior material by further including a fiber assembly of single or PET alone. The automobile interior material may be a known type of interior material, and preferably may be used as a subsidiary material inside a vehicle in consideration of excellent sound absorption, adhesive strength, flame retardancy, heat resistance, and low VOCs emission amount, and may be particularly suitable for a seat back, for example. have.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, which should be construed to aid understanding of the present invention.

<Example 1>

38 mol% of the compound represented by the following formula (1) as a diol component, 3 mol% of the compound represented by the following formula (2), and 59 mol% of ethylene glycol as the remaining diol component are added, and 100 mol% of terephthalic acid is added as an acidic component. The component and the diol component were esterified at 250° C. at a ratio of 1:1.2 under 1140 torr pressure to obtain an ester reaction product, and the reaction rate was 97.5%. Transfer the formed ester reaction product to a polycondensation reactor, and add 15 ppm of a compound represented by the following formula 4 (based on Ti element) as a polycondensation catalyst, and 25 ppm of triethyl phosphate (based on element P) as a heat stabilizer to bring the final pressure to 0.5 Torr. A copolyester was prepared by gradually increasing the temperature to 285°C while reducing pressure to perform a condensation polymerization reaction, and then the copolyester was prepared as a polyester chip having a width, length, and height of 2mm×4mm×3mm, respectively, by a conventional method. .

Thereafter, in order to prepare a core-sheath type composite fiber with the copolyester as a sheath and a polyethylene retephthalate (PET) having an intrinsic viscosity of 0.65 dl/g as the core, the copolyester chips and PET chips were respectively added to the hopper. After melting and putting them into a core sheath type spinneret respectively, the core and sheath were combined to have a weight ratio of 5:5 at a spinning speed of 1000mpm under 275℃, and stretched 3.0 times to have a fiber length of 51mm and a fineness of 4.0de. A core-sheath type heat-adhesive fiber as shown in Table 1 was prepared.

[Formula 1]

[Formula 2]

[Formula 4]

<Examples 2 to 14>

Prepared by carrying out the same manner as in Example 1, but by changing the composition ratio of the monomer for producing the copolyester as shown in Table 1, Table 2, or Table 3 below, the core-sheath type composite fiber as shown in Table 1, Table 2, or Table 3 Tear heat-adhesive fibers were prepared.

<Comparative Examples 1 to 4>

Prepared in the same manner as in Example 1, but by changing the composition of the monomer for the production of the copolyester as shown in Table 3 below, a polyester chip as shown in Table 3 and a heat-adhesive fiber, which is a core sheath type composite fiber using the same, were prepared. .

<Experimental Example 1>

During the manufacture of the heat-adhesive fibers implemented according to Examples and Comparative Examples, the following physical properties were evaluated for the copolyester chips, core sheath type heat-adhesive fibers, or fiber aggregates produced using the intermediates, and the results are as follows. It is shown in Tables 1 to 3.

At this time, the fiber aggregate is a heat-adhesive fiber and polyethylene terephthalate (PET) short fiber (fiber length 51 mm, fineness 4.0de) at a temperature of 120°C, 140°C and 160°C, respectively, after mixing and opening at a weight ratio of 5 to 5 A total of 3 types of fiber aggregates with a basis weight of 35g/m2 were subjected to heat treatment under conditions.

1. Intrinsic viscosity

For copolyester chips, ortho-chlorophenol (Ortho-Chloro Phenol) is used as a solvent and melted at a concentration of 110°C and 2.0g/25ml for 30 minutes, and then incubated at 25°C for 30 minutes, and a CANON viscometer is connected. Analysis from an automatic viscosity measuring device.

2. Glass transition temperature, melting point

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

3. Copolyester chip drying time

After the polycondensed copolyester resin was chipped, the moisture content was measured in a vacuum dryer at 55° C. at 4 hour intervals, and the time was expressed as the drying time when the moisture content was 100 ppm or less as a result of the measurement.

4. Short fiber storage stability

For 500 g of the manufactured core sheath type composite fiber, 10 experts observed the state of fusion between fibers by applying pressure 2kgf/㎠ in a chamber with a temperature of 40°C and a relative humidity of 45% for 3 days. The case was evaluated as 0 to 10 points based on 10 points and 0 points for all cases where fusion occurred, and then the average value was calculated. As a result, when the average value was 9.0 or more, it was very good (◎), when it was 7.0 or more and less than 9.0, it was excellent (○), 5.0 or more and less than 7.0 were indicated as normal (△), and less than 5.0 was indicated as bad (×).

5. Spinning workability

Spinning workability occurs during spinning process for core sheath type composite fibers spun in the same amount for each Example and Comparative Example (means a lump formed by fusion of some of the fiber strands passing through the detention or irregular fusion of the strands after trimming) Numerical values were counted through a drip detector, and the number of drips generated in the remaining Examples and Comparative Examples was expressed as a relative percentage based on the number of drip occurrences in Example 1 as 100.

6. Evaluation of dyeing rate

After performing a dyeing process at 90°C for 60 minutes at a bath ratio of 1:50 for a dye solution containing 2% by weight of blue dye based on the weight of the core sheath type composite fiber, Japan's KURABO After measuring the spectral reflectance of the visible region (360 ~ 740nm, 10nm interval) of the dyed composite fiber using the company's color measurement system, the total K/S value, an index of the amount of dyeing according to the CIE 1976 standard, was calculated. The color yield of the dye was evaluated.

7. Adhesion strength

Each of the three fiber aggregates was implemented as a specimen having a width, length and thickness of 100 mm × 20 mm × 10 mm, respectively, and the adhesive strength was measured using a universal testing machine (UTM) according to the KS M ISO 36 method.

On the other hand, when the shape was deformed due to excessive shrinkage during heat treatment, the adhesive strength was not evaluated, but was evaluated as'shape deformation'.

8. Soft touch

Among the three fiber aggregates, a sensory test by a group of 10 experts in the same industry was conducted on the fiber aggregates produced by heat treatment at a temperature of 140°C, and the evaluation result was excellent when 8 or more were judged to be soft (◎ ), 6 to 7 were classified as good (○), 5 to 4 were normal (△), and less than 4 were classified as bad (×).

		Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7
Acid (mole%)	TPA	100	100	100	100	100	100	100
	IPA	0	0	0	0	0	0	0
	total	100	100	100	100	100	100	100
Dior ingredient (mole%)	EG	59	56	53.5	50	66	69.5	71.5
	Compound of Formula 1	38	39	40	47	32.8	27.5	25.5
	Compound of Formula 2	3	5	6.5	3	1.2	3	3
	DEG	0	0	0	0	0	0	0
	total	100	100	100	100	100	100	100
	Formula 1 + Formula 2	41	44	46.5	50	34	30.5	28.5
Polyester chip	IV	0.628	0.632	0.632	0.638	0.643	0.640	0.645
	Melting point(℃)	none	none	none	none	none	none	187
	Tg(℃)	68	68	67	63	67	71	73
	Drying time (Hr)	44	44	44	48	44	28	24
Composite fiber	Spinning workability (%)	100	100	116	285	97	92	90
	Short fiber storage stability	◎	◎	◎	○	◎	◎	◎
	Dyeing rate (K/S)	16	17	17	15	14	12	11
Fiber assembly	120℃ adhesive strength (N)	110	107	89	65	63	38	Non-adhesive
	140℃ adhesive strength (N)	141	139	138	115	104	60	47
	160℃ adhesive strength (N)	184	179	176	173	139	91	76
	Soft touch	◎	◎	◎	◎	○	△	△

		Example 8	Example 9	Example 10	Example 11	Example 12
Acid (mole%)	TPA	100	100	100	100	100
	IPA	0	0	0	0	0
	total	100	100	100	100	0
Dior Ingredient (mol%)	EG	69.5	69.5	67	72	66
	Compound of Formula 1	21	18.5	21	18.5	33.5
	Compound of Formula 2	9.5	12	12	9.5	0.5
	DEG	0	0	0	0	0
	total	100	100	100	100	100
	Formula 1 + Formula 2	30.5	30.5	33	28	34
Polyester chip	IV	0.643	0.640	0.642	0.643	0.638
	Melting point(℃)	none	none	none	187	none
	Tg(℃)	72	73	72	73	67
	Drying time (Hr)	24	20	24	20	48
Composite fiber	Spinning workability (%)	86	84	98	81	108
	Short fiber storage stability	◎	◎	◎	◎	○
	Dyeing rate (%)	13	11	13	11	15
Fiber assembly	120℃ adhesive strength (N)	72	46	60	Non-adhesive	43
	140℃ adhesive strength (N)	113	89	98	29	90
	160℃ adhesive strength (N)	140	133	141	52	125
	Soft touch	△	△	△	△	○

		Example 13	Example 14	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4
Acid (mole%)	TPA	100	97	100	100	80	100
	IPA	0	3	0	0	20	0
	total	100	100	100	100	100	100
Dior Ingredient (mol%)	EG	60	62	63	60	80	63
	Compound of Formula 1	15	35	37	33	0	0
	Compound of Formula 2	22	3	0	0	10	37
	DEG	0	0	0	7	10	0
	total	100	100	100	100	100	100
	Formula 1 + Formula 2	37	38	37	33	10	37
Polyester chip	IV	0.653	0.635	0.642	0.640	0.638	0.638
	Melting point(℃)	none	none	none	none	none	none
	Tg(℃)	72	66	65	62	66	75
	Drying time (Hr)	28	44	52	52	56	20
Composite fiber	Spinning workability (%)	360	96	110	155	220	486
	Short fiber storage stability	◎	◎	○	×	△	◎
	Dyeing rate (%)	13	16	16	16	15	13
Fiber assembly	120℃ adhesive strength (N)	Shape transformation	120	91	75	98	Shape transformation
	140℃ adhesive strength (N)	Shape transformation	143	126	104	129	Shape transformation
	160℃ adhesive strength (N)	Shape transformation	164	152	136	151	Shape transformation
	Soft touch	-	◎	◎	◎	◎	-

As can be seen from Tables 1 to 3,

In Comparative Examples, the drying time was significantly extended (Comparative Examples 1 to 3), spinning workability was remarkably good (Comparative Example 2, Comparative Example 3), or short fiber storage stability was very poor (Comparative Example 2, Comparative Example 3). ), it can be confirmed that the shape is deformed (Comparative Example 4) in the evaluation of the adhesive strength by temperature, so it can be confirmed that all physical properties cannot be satisfied at the same time, but it can be confirmed that the examples express all physical properties at an excellent level. .

On the other hand, in Example 15, in which the content of the compound represented by Formula 2 was higher than that of the compound represented by Formula 1, the shape was changed in the adhesive strength evaluation by temperature compared to the other examples to achieve the desired physical properties. It can be confirmed that it is not suitable for.

<Examples 15 to 27>

Preparation was carried out in the same manner as in Example 1, but the composition ratio of the monomer for preparing the copolyester was changed as shown in Tables 4 and 5 to prepare a copolyester, and when the composite fiber was spun at 5:5, the core and The heat-adhesive fibers as shown in Tables 4 and 5 were prepared with phosphorus-based flame retardants in both the sheath and the core by further including a phosphorus-based flame retardant represented by the following Chemical Formula 3 in the sheath portion in the amount of Table 4 and Table 5 below. At this time, the content of the phosphorus-based flame retardant in Tables 4 and 5 is based on the heat-adhesive fiber. The unit of content of the acidic component and the diol component is mol%, and the remaining amount of the diol component is ethylene glycol (EG).

[Formula 3]

In this case, in Chemical Formula 3, it is a straight-chain alkylene group having 3 carbon atoms, n is an integer of 10, and m is an integer of 40.

<Comparative Example 5 and Comparative Example 6>

Preparation was carried out in the same manner as in Example 15, but a heat-adhesive fiber was prepared by changing the composition ratio of the monomer for preparing the copolyester as shown in Table 5 below.

<Experimental Example 2>

The following physical properties were evaluated for the heat-adhesive fibers implemented according to Examples 15 to 27, Comparative Examples 5 and 6, or fiber aggregates using the same, and the results are shown in Tables 4 and 5 below.

At this time, the fiber aggregate is blended and opened in a weight ratio of 5: 5 to a heat-adhesive fiber (fiber length 51 mm, fineness 4.0de) and polyethylene terephthalate (PET) short fiber (fiber length 51 mm, fineness 7.0de) in a weight ratio of 5:5. The fiber aggregates were subjected to heat treatment at 140° C. for 15 minutes to have a basis weight of 330 g/m 2.

1. Heat adhesive fiber strength evaluation

Fiber strength was measured using the Textechno's FAVIMAT Fiber Test facility, and the analysis condition was that the jig movement speed was 600 mm/min.

2. Flame retardancy measurement

The carbonization distance and residual time of the nonwoven fabric were measured according to the MS 300-08 method of the fire resistance test of automobile materials.

3. Acetaldehyde (AA) generation amount of heat-adhesive fiber

According to the MS 300-55 Method, the amount of acetaldehyde generated in the heat-adhesive fiber was measured.

4. Heat resistance

The width, length and thickness of each 100mm×20mm×10mm, 330g/㎡ specimen were exposed in an environment at 90°C for about 2 hours, and then both ends of the specimen in the longitudinal direction were fixed, and the deflection width of the sagging part was measured. . At this time, the sag width was measured based on the lower surfaces of both ends, and the maximum value was taken as the high temperature sag value.

		Example 15	Example 16	Example 17	Example 18	Example 19	Example 20	Example 21
Acid content (mol%)	TPA	100	100	100	100	100	100	100
	IPA	0	0	0	0	0	0	0
Diol component (mol%)	Compound of Formula 1	40	40	40	40	40	40	26
	Compound of Formula 2	One	One	One	One	One	One	One
	Formula 1 + Formula 2	41	41	41	41	41	41	27
P content (ppm)		6,000	4,000	5,000	5,500	6,500	7,000	6,000
Properties	Fiber strength (g/d)	4.2	4.3	4.3	4.3	3.9	3.2	4.4
	AA generation (ppb)	1523	1511	1530	1525	1520	1522	2228
	Carbonization distance (mm)	42	76	55	45	38	34	42
	Residual time (seconds)	50	69	64	53	46	43	48
	Equation 1	35	87.4	58.7	39.8	29.1	24.4	33.6
	High temperature sag (㎜)	20	19	19	19	20	20	9

		Example 22	Example 23	Example 24	Example 25	Example 26	Example 27	Comparative Example 5	Comparative Example 6
Acid content (mol%)	TPA	100	100	100	100	95	90	85	80
	IPA	0	0	0	0	5	10	15	20
Diol component (mol%)	Compound of Formula 1	30	32	42	46	35	30	25	20
	Compound of Formula 2	One	One	One	One	One	One	One	One
	Formula 1 + Formula 2	31	33	43	47	36	31	26	21
P content (ppm)		6,000	6,000	6,000	6,000	6,000	6,000	6,000	6,000
Properties	Fiber strength (g/d)	4.3	4.3	4.2	3.8	4.4	4.2	4.1	4.2
	AA generation (ppb)	1906	1582	1010	887	1551	2301	2887	3179
	Carbonization distance (mm)	42	43	42	44	41	42	43	42
	Residual time (seconds)	49	51	52	56	51	50	51	52
	Equation 1	34.3	36.6	36.4	41.1	34.9	35	36.6	36.4
	High temperature sag (㎜)	9	11	40	62	13	18	22	24

As can be seen from Table 4 and Table 5,

It can be seen that Comparative Examples 5 and 6 generate an excessive amount of acetaldehyde compared to other examples, whereas the examples according to the present invention generate less acetaldehyde, which is very suitable for automobile interior materials.

<Experimental Example 3>

For the fiber aggregates prepared using the heat-adhesive fibers according to Examples 15 to 20, the adhesive strength was evaluated by the following method, and the results are shown in Table 6 below.

The fiber aggregate was mixed with heat-adhesive fibers (fiber length 51 mm, fineness 4.0de) and polyethylene terephthalate (PET) short fibers (fiber length 51 mm, fineness 7.0de) at a weight ratio of 5: 5, and then at 140°C, A fiber aggregate produced with a basis weight of 330g/m2 by heat treatment under the condition of 15 minutes was targeted.

The adhesive strength of the specimen was measured 12 times using Instron® (tensile speed 500㎜/min, Load-Cell 2kN, Grip 5kN) equipment under the conditions. The average value was calculated. At this time, the specimen was 100 mm × 20 mm × 10 mm in width, length, and thickness, respectively.

		Example 15	Example 16	Example 17	Example 18	Example 19	Example 20
Diol component	Compound of Formula 1	40	40	40	40	40	40
	Compound of Formula 2	One	One	One	One	One	One
	Formula 1 + Formula 2	41	41	41	41	41	41
P content in composite fiber (ppm)		6,000	4,000	5,000	5,500	6,500	7,000
Adhesive strength (N)		147	150	149	149	144	130

As can be seen from Table 6, it can be seen that in the case of Example 20 in which the phosphorus-based flame retardant is provided somewhat in the sheath of the heat-adhesive fiber, the adhesive strength is lowered.

Although an embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same idea. It will be possible to easily propose other embodiments by changing, deleting, adding, etc., but it will be said that this is also within the scope of the present invention.

Claims (12)

1. A core containing a polyester-based component; And

   An acidic component containing terephthalic acid, and a copolyester in which an esterified compound in which ethylene glycol and a diol component including a compound represented by the following Formula 1 and a diol component including a compound represented by Formula 2 are reacted is polycondensed, and the core part A heat-adhesive fiber that includes, and has an acetaldehyde (AA) generation amount of 2400 ppb or less according to the MS 300-55 method:

   [Formula 1]

   

   [Formula 2]

   
2. The method of claim 1,

   A heat-adhesive fiber, characterized in that the total amount of the compound represented by Formula 1 and the compound represented by Formula 2 is contained in an amount of 30 to 45 mol% of the diol component.
3. The method of claim 1,

   Heat-adhesive fiber, characterized in that the content of the compound represented by Formula 1 in the diol component is greater than the content of the compound represented by Formula 2.
4. The method of claim 1,

   Of the diol component, the compound represented by Formula 1 is 20 to 40 mol%, and the compound represented by Formula 2 is included in 0.8 to 10 mol%.
5. The method of claim 1,

   The core portion is a heat-adhesive fiber, characterized in that it further comprises a phosphorus-based flame retardant represented by the following formula (3) 5500ppm to 6500ppm based on a phosphorus content:

   [Formula 3]

   

   At this time, in Formula 3, R is an alkylene group having 1 to 5 carbon atoms, n is an integer of 1 to 20, and m is an integer of 1 to 80.
6. The method of claim 5,

   Heat-adhesive fiber, characterized in that the sheath of the heat-adhesive fiber further comprises 5500ppm to 6500ppm of the phosphorus-based flame retardant represented by Chemical Formula 3 based on a phosphorus content.
7. The method of claim 1,

   Heat-adhesive fiber, characterized in that it contains acetaldehyde (AA) generation amount of 1950 ppb or less.
8. The heat-adhesive composite fiber according to any one of claims 1 to 7; And

   A fiber assembly for automobile interiors containing; polyester-based support fibers having a melting point higher than 250°C.
9. The method of claim 8,

   The heat-adhesive fiber and the support fiber is a fiber assembly for automobile interior material, characterized in that included in a weight ratio of 70:30 to 30:70.
10. The method of claim 8,

    Fiber aggregates for automobile interiors satisfying the following conditions (1) and (2):

    (1) The value according to Equation 1 below is 27 to 55

    [Equation 1]

    

    In Equation 1, D and T are the carbonization distance and residual time measured by the MS 300-08 method, respectively, and the specimen is a heat-adhesive fiber (fiber length 51 mm, fineness 4.0de) and polyethylene terephthalate (PET ) A fiber aggregate manufactured with a basis weight of 330g/m2 by blending and opening a single fiber (fiber length 51㎜, fineness 7.0de) at a weight ratio of 5:5 and heat treatment at 180℃ for 15 minutes.

    (2) High temperature sag is less than 45mm.
11. The method of claim 10,

    In the condition (2), the high-temperature sag is 20 mm or less.
12. A vehicle interior material comprising the fiber assembly for automotive interior materials according to claim 8.

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