An automotive interior containing knitted fabric

Abstract

The present invention relates to a lightweight automotive interior material comprising: a skin layer including a ground layer and a pile layer; a coating layer laminated below the skin layer; and a high-rigidity felt layer laminated below the coating layer.

Description

Technology Field

[0001] The present invention relates to an automotive interior material comprising a knitted fabric, and more specifically, to an automotive floor material or trunk trim interior material comprising a knitted fabric having excellent sound insulation and sound absorption properties. Background Technology

[0002] Generally, various interior materials are installed on car door trims, headlinings, instrument panels, pillars, consoles, floor carpets, trunks, etc.

[0003] In particular, floor carpets are installed on floor panels and the like to block or absorb noise transmitted from the floor. Noise entering through the vehicle floor can be broadly classified into noise generated by the engine that enters through the vehicle body, and noise generated when tires come into contact with the road surface that enters through the vehicle body.

[0004] There are two methods to mitigate such noise: improving sound absorption performance and improving sound insulation performance. Sound absorption refers to the process where generated sound energy is transmitted through internal pathways of a material, converted into thermal energy, and dissipated, whereas sound insulation refers to the process where generated sound energy is reflected and blocked by a shielding material.

[0005] To improve sound absorption performance, it is common practice to incorporate a felt layer using low-fineness fibers and a high concentration of fine open-cell particles, such as urethane foam. However, since the sound insulation layer is constructed with high weight to enhance sound insulation performance, there are issues such as worsened fuel efficiency due to increased vehicle body weight and rising production costs due to additional material expenses. Therefore, the trend is to shift from sound insulation structures that block noise to sound absorption structures that absorb noise, aiming to reduce weight and improve workability.

[0006] Since electric vehicles are inevitably heavier than internal combustion engine vehicles, lightweighting can drastically improve efficiency and driving range, leading to a concentrated interest in lightweight materials for electric vehicles. Prior art literature

[0007] Published Patent Application No. 10-2020-0000121 (Published Jan. 2, 2020) The problem to be solved

[0008] The present invention aims to provide a lightweight interior material for automobiles comprising a knitted fabric, and specifically, to provide an interior material for automobile flooring or trunk trim that enables the curing of the electric vehicle and offers excellent sound insulation and sound absorption when the interior material comprising the knitted fabric according to the present invention is used in an electric vehicle. means of solving the problem

[0009] A lightweight interior material for automobiles according to the present invention may include a skin layer comprising a ground layer and a pile layer; a coating layer laminated below the skin layer; and a high-rigidity felt layer laminated below the coating layer.

[0010] In a lightweight interior material for automobiles according to one embodiment of the present invention, a foam layer may be further included below the high-rigidity felt layer.

[0011] In a lightweight interior material for automobiles according to one embodiment of the present invention, the ground layer may be a knitted fabric.

[0012] In a lightweight interior material for automobiles according to one embodiment of the present invention, the surface layer may be formed by bonding a fiber pile to a knit fabric.

[0013] In a lightweight interior material for automobiles according to one embodiment of the present invention, the bonding may be achieved by a double raschel warp knitting machine.

[0014] In a lightweight interior material for an automobile according to one embodiment of the present invention, the knit fabric may be a knit fabric knitted from polyethylene terephthalate filaments.

[0015] In a lightweight interior material for automobiles according to one embodiment of the present invention, the fiber pile may be made of 100% polyester fiber.

[0016] In a lightweight interior material for automobiles according to one embodiment of the present invention, the coating layer may comprise polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene vinyl acetate resin, or polyurethane resin.

[0017] In a lightweight interior material for an automobile according to one embodiment of the present invention, the foam layer may include a thermoplastic elastomer. Effects of the invention

[0018] The lightweight interior material for automobiles comprising a knitted fabric according to the present invention enables the lightweighting of electric vehicles and has excellent sound absorption and sound insulation properties.

[0019] In addition, the lightweight interior material for automobiles comprising the knit fabric according to the present invention has excellent durability so that it does not get scratched when used by the user, as well as excellent heat and cold resistance, excellent flame resistance, and can reduce VOC generation.

[0020] A lightweight interior material for automobiles comprising a knitted fabric according to the present invention can improve moldability, pile strength, and the shedding of pile fibers in the pile layer. Brief explanation of the drawing

[0021] FIG. 1 shows an interior structure for an automobile according to one example of the present invention ((a): Example 1, (b): Example 3, (c): Comparative Example 4). Figure 2 is a graph comparing the sound absorption of automobile floor carpets manufactured with the interior materials of Example 3 and Comparative Example 2 of the present invention. Figure 3 is a graph comparing the sound insulation of automobile floor carpets manufactured with the interior materials of Example 3 of the present invention and Comparative Example 2. Specific details for implementing the invention

[0022] The present invention will be described in more detail below through specific examples or embodiments, including the attached drawings. However, the following specific examples or embodiments are merely references for the detailed description of the present invention and the present invention is not limited thereto and may be implemented in various forms.

[0023] Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as generally understood by one of the people skilled in the art to which this invention pertains. The terms used in the description of this invention are intended merely to effectively describe specific embodiments and are not intended to limit the invention.

[0024] Additionally, the singular form used in the specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context.

[0025] Furthermore, when it is stated that a part “includes” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0026] A lightweight automotive interior material comprising the knit fabric of the present invention is described below.

[0027] An automotive interior material comprising a knitted fabric according to the present invention may be an interior material for an electric vehicle.

[0028] The interior material comprising the knit fabric according to the present invention may be a carpet for the floor of an electric vehicle or a carpet for the trunk trim. In addition, the knit fabric may be used as a ground layer of the surface layer included in the interior material.

[0029] The present invention provides a lightweight automotive interior material comprising: a skin layer including a ground layer and a pile layer; a coating layer laminated below the skin layer; and a high-rigidity felt layer laminated below the coating layer.

[0030] The ground layer may include a knitted fabric. The knitted fabric may be knitted with polyethylene terephthalate filaments, and the knitted fabric may be knitted using yarn composed of 40 to 200 strands of multifilaments. The fineness of the yarn may be 80 to 300 denier, and preferably 90 to 270 denier. A single strand of filament may be 0.4 to 7.5 denier.

[0031] The pile layer included in the ground layer and combined with the knit fabric is composed of pile fibers made of 100% polyester fibers, or the pile layer may include loops made of 100% polyester fibers.

[0032] The pile fibers or loops forming the pile layer may be combined at a rate of 600 to 1,200 per meter in the horizontal and vertical directions of the knit fabric, respectively. The combination may be achieved by knitting the pile fibers and the knit fabric, specifically by using a Raschel warp knitting machine. Alternatively, the loops formed on the surface of the knit fabric may be formed during the knit fabric manufacturing process.

[0033] The pile fiber or loop may be composed of 100% polyester fiber, and the 100% polyester fiber may be a latent crimpable polyester fiber. Specifically, it may be composed of a polytrimethylene terephthalate (PTT) resin having an intrinsic viscosity of 0.96 to 1.20 and a polyethylene terephthalate (PET) resin having an intrinsic viscosity of 0.40 to 0.55, and the weight ratio of the PTT resin and the PET resin may be 45:55 to 55:45, and the PTT and PET in the weight ratio may be side-by-side composite fibers and may have a crimp of 30 to 100 EA / inch.

[0034] If the weight ratio of the above PTT resin is less than 45, crimping is reduced, and if the weight ratio of the above PET resin is less than 45, there is a problem that it becomes difficult to spin into side-by-side composite fibers.

[0035] If the intrinsic viscosity of the above PTT resin is less than 0.96, the melting point of the spun side-by-side composite fiber is too low, resulting in poor spinning, and the low thermal shrinkage stress leads to insufficient crimping, which may reduce the sound absorption and sound insulation effects of automotive interior materials. In addition, if the intrinsic viscosity of the above PTT resin exceeds 1.20, the spinning process may be poor due to the high melting viscosity. If the intrinsic viscosity of the above PET resin falls outside the range of 0.40 to 0.55, crimping may be insufficient. From the perspective of spinnability and crimping, a difference in intrinsic viscosity between the above PTT resin and PET resin of 0.96 to 1.20 and 0.40 to 0.55 may be appropriate. Furthermore, from the perspective of the spinnability of the side-by-side composite fiber and easy crimping by heat treatment, a difference in melting viscosity between the above PTT resin and PET resin of 1500 to 2500 poise may be appropriate. If the above range of melting viscosity difference is satisfied, a shape can be formed where the high viscosity side penetrates the low viscosity side, and the curvature of the interface shape can change depending on the difference in melting viscosity.

[0036] A side-by-side composite fiber composed of PTT resin and PET resin having the above characteristics may have a crimp modulus of 40 to 50% and a crimp recovery rate of 30 to 40%. If the above crimp modulus and crimp recovery rate are satisfied, the flexibility and elasticity of the automotive interior material are improved.

[0037] The basis weight of a ground layer comprising a knitted fabric and a skin layer comprising a pile layer formed of pile fibers or loops is 300 to 500 g / m² 2 It may be, or 320 to 470 g / m² 2 It may be, or 350 to 450 g / m² 2 It may be possible. By including an epidermal layer, which is a pile layer bonded to a knitted fabric serving as a ground layer, in the lightweight interior material for automobiles according to the present invention, not only is the touch and flexibility of the interior material improved, but a sound reduction effect can also be obtained due to the numerous voids formed by the coils constituting the knitted fabric. In addition, the epidermal layer may have excellent durability and may have the advantage of not being scratched during use.

[0038] The coating layer laminated beneath the above-mentioned epidermal layer may comprise a VOC-free (Volatile Organic Compounds-free) foamed latex layer or polypropylene resin, and the basis weight of the coating layer is 800 to 1,400 g / m² 2 It may be, or 900 to 1,300 g / m² 2 It may be, or 1,000 to 1,200 g / m² 2 1, or 1,000 to 1,100 g / m² 2 It may be. The coating layer may serve as a binder layer that fixes the skin layer provided on the upper side and the high-rigidity felt layer laminated below the coating layer. The coating layer may have flame retardancy.

[0039] The above VOC-free foamed latex layer may be a composition comprising polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene vinyl acetate resin, polypropylene resin, polyurethane resin, or a mixture thereof, but is not limited thereto.

[0040] The above coating layer may be formed from a composition including polypropylene.

[0041] The coating layer according to the present invention not only serves as a binder that combines the skin layer and the high-rigidity felt layer, but can also be used as a sound insulation layer having flame retardancy if it is composed of a composition comprising 200 to 400 parts by weight of an inorganic filler per 100 parts by weight of polyethylene vinyl acetate resin or polypropylene resin.

[0042] The above inorganic filler may comprise one or more mixtures selected from the group consisting of wollastonite, calcium carbonate, kaolin, mica, silica, chalk, fine dolomite, talc, iron oxide, titanium dioxide, glass powder, magnesium carbonate, aluminum hydroxide, bentonite, volcanic ash, diatomite, barium sulfate, aluminum oxide, nanoclay, and graphite, but is not limited thereto.

[0043] A high-rigidity felt layer laminated beneath a coating layer of a lightweight interior material for automobiles according to the present invention may be included. The basis weight of the high-rigidity felt layer is 300 to 700 g / m² 2 It may be, or 400 to 600 g / m² 2It may be. The thickness of the high-rigidity felt layer may be 5 to 20 mm, or 8 to 15 mm. The high-rigidity felt layer may include high-rigidity fibers, and the high-rigidity fibers may be fibers with an irregular cross-section, specifically, fibers with a 3-lobed to 5-lobed cross-section. In this case, the degree of irregularity may be 2.0 to 3.7. The cross-sectional perimeter of the irregular cross-section fiber having the degree of irregularity may be 200 to 250 μm, and the fiber cross-sectional area may be 700 to 800 μm. 2 It may be possible. In this case, the transverse length of the fiber cross-section may be 30 to 50 μm, and the longitudinal length of the fiber cross-section may be 20 to 30 μm. Including fibers with a different cross-section having the above degree of irregularity can suppress excessive shrinkage during thermoforming due to voids between fibers created within the felt layer, and at the same time, control the occurrence of problems such as reduced stiffness.

[0044] The above-mentioned irregular cross-section fiber may be one or more fibers selected from the group consisting of polyethylene terephthalate fiber, polypropylene fiber, acrylic fiber, viscose rayon, and aramid fiber.

[0045] The high-rigidity felt layer may comprise 50 to 70 weight percent of irregular cross-sectional fibers and 30 to 50 weight percent of PET fibers having a sheath portion with a melting point of 110 to 130°C and a core portion with a melting point of 230 to 260°C, and may comprise 20 to 30 weight percent of the sheath portion and 70 to 80 weight percent of the core portion, but is not limited thereto. If the irregular cross-sectional fibers included in the high-rigidity felt layer are less than 50 weight percent, problems such as excessive shrinkage and reduced rigidity occur during processes such as thermoforming in the manufacturing process of automotive carpets, and if it exceeds 70 weight percent, the content of PET fibers with a sheath-core structure decreases, resulting in problems such as poor mechanical properties after molding, such as carpet shape, tensile strength, dimensional change rate, elongation, flexural modulus, and tear strength.

[0046] In addition, if the melting point of the sheath portion of the PET fiber with a sheath-core structure is less than 110°C, the fiber melts excessively during the thermoforming process, causing the felt layer to become hard and making it difficult to deform under external stress, which limits its use as an automotive part. Also, if it exceeds 130°C, it requires an excessive heat temperature that is not suitable for the thermoforming process of a typical felt layer, which limits it in terms of economics.

[0047] When the core of the PET fiber with the above-mentioned sheath-core structure has a melting point of less than 230°C, the difference in melting temperature with the sheath is small, which limits the rigidity of the core that acts as a wick, and when it exceeds 260°C, the difference in melting point with the sheath is large, so when spinning the fiber with the double structure, excessive shrinkage of the sheath occurs.

[0048] When considering the transmission loss, which is the stiffness and noise reduction performance of the automotive interior material according to the present invention, it is preferable to use a PET fiber composed of a sheath portion of 20 to 30 weight percent and a core portion of 70 to 80 weight percent. In practice, if the content of the sheath portion, which acts as an adhesive, is less than 20 weight percent, the adhesive component is weak and the stiffness of the part is reduced; conversely, if it exceeds 30 weight percent, the stiffness of the felt layer is excessive and there is a problem of poor assembly performance.

[0049] The total weight (basis weight) of the skin layer, coating layer, and high-rigidity felt layer included in the lightweight interior material for automobiles according to the present invention is 1,600 g / m² 2 It may be more than, or 1,700 g / 2 It may be greater than or equal to 1,800 g / m² 2 It may be greater than or equal to 1,900 g / m² 2 It may be more than that. Or the above knit fabric is 2,400 g / m 2 It may be less than or equal to 2,300 g / m² 2 It may be less than or equal to 2,200 g / m² 2 It may be less than or equal to 2,100 g / m² 2 It may be less than or equal to 1,600 to 2,400 g / m². Specifically, 1,600 to 2,400 g / m² 2 , 1,700 ~ 2,300 g / m 2 , 1,800 ~ 2,200 g / m 2 , 1,900 ~ 2,100 g / m 2 , 1,950 ~ 2,050 g / m 2 It could be.

[0050] The lightweight interior material for automobiles according to the present invention may be composed of the skin layer, coating layer, and high-rigidity felt layer described above, or may further include a foam layer in the interior material for automobiles comprising the skin layer, coating layer, and high-rigidity felt layer.

[0051] The above foam layer may be further laminated beneath the high-rigidity felt layer. Additionally, the foam layer may include a thermoplastic elastomer.

[0052] The above thermoplastic elastomer may include one or more thermoplastic elastomers selected from styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, thermoplastic pressurized vulcanized products, thermoplastic polyamides, thermoplastic copolymers, and thermoplastic polyurethanes. Specifically, it may include one or more thermoplastic elastomers selected from thermoplastic polyamides, thermoplastic polyurethanes, and styrene-based thermoplastic elastomers, and specifically, it may be a thermoplastic polyurethane elastomer, but is not limited thereto.

[0053] The above thermoplastic polyurethane elastomer may specifically be a soft or hard thermoplastic polyurethane resin, and is not limited to commercially available polyurethane elastomers.

[0054] The weight-average molecular weight of the above thermoplastic polyurethane elastomer may be 20,000 g / mol to 5,000,000 g / mol, specifically 100,000 g / mol to 3,000,000 g / mol, but is not limited thereto.

[0055] The melt index of the above thermoplastic elastomer may be 5 to 25 g / 10 min under conditions of 205°C and 2.16 kg in accordance with ASTM D1238, specifically 10 to 20 g / 10 min, but is not limited thereto.

[0056] When the above-mentioned thermoplastic polyurethane elastomer is included in the automotive interior material of the present invention, it exhibits excellent resilience against external stress and wear resistance, and the automotive interior material has excellent damping performance (NVH performance) at low temperatures, thereby enabling noise reduction even at low temperatures. Furthermore, when the foam layer includes the thermoplastic elastomer, the high-rigidity felt layer laminated on the foam layer can reduce resistance to external deformation due to the elasticity of the thermoplastic elastomer.

[0057] The above foam layer may further include inorganic fillers, and accordingly, durability and heat resistance may be improved.

[0058] The above inorganic filler may comprise one or more mixtures selected from the group consisting of wollastonite, calcium carbonate, kaolin, mica, silica, chalk, fine dolomite, talc, iron oxide, titanium dioxide, glass powder, magnesium carbonate, aluminum hydroxide, bentonite, volcanic ash, diatomite, barium sulfate, aluminum oxide, nanoclay, and graphite, but is not limited thereto.

[0059] The above inorganic filler may be included in an amount of 70 to 150 parts by weight per 100 parts by weight of the thermoplastic elastomer, and when such an amount of inorganic filler is included in the foam layer, not only is the durability and heat resistance of the foam layer improved, but the processability, tensile strength, and tensile elongation are also excellent, and there is an advantage of low specific gravity.

[0060] The above foam layer may further include conventional additives, and the additives may be any one selected from thermal stabilizers, flame retardants, impact modifiers, and colorants, or a mixture thereof.

[0061] The above heat stabilizer is not limited to those commonly used in this field, but specifically, for example, it may be any one selected from trimethyl phosphite, triethyl phosphite, trisnonylphenylphosphite, trimethylphosphate, tri(2,4-di-tert-butylphenyl)phosphite and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite or a mixture thereof.

[0062] The above flame retardant is not limited to those commonly used in this field, but specifically, for example, may be any one selected from metal hydroxides, metal oxides, nitrogen-based compounds, fluoropolymers, phosphorus-based compounds, and silicone oils, or a mixture thereof.

[0063] The above impact modifier is not limited to those commonly used in this field, but specifically, for example, it may be any one selected from methyl methacrylate-butadiene styrene (MBS), chlorinated polyethylene (CPE), and silicon dioxide, or a mixture thereof.

[0064] The above-mentioned coloring agent is not limited to those commonly used in this field, but specifically, carbon black can be cited as a matte pigment for automobiles.

[0065] The above additive may be included in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the thermoplastic polyurethane elastomer included in the foam layer, but is not limited thereto.

[0066] A method for manufacturing an interior material for an electric vehicle including a knitted fabric according to the present invention will be described below.

[0067] The present invention provides a method for manufacturing a lightweight automotive interior material comprising: (a) a step of manufacturing a skin layer including a ground layer and a pile layer; (b) a step of forming a coating layer on the underside of the manufactured skin layer; and (c) a step of forming a high-rigidity felt layer on the underside of the coating layer.

[0068] The step of manufacturing an epidermal layer including (a) a ground layer and a pile layer may include the following process.

[0069] A warping process can be performed in which yarn and pile fibers are wound onto respective beams. The yarn is knitted into a knit fabric to form a ground layer, and the pile fibers are composed of bonding yarns that combine two knit fabrics. At this time, the number of beams on which the yarn is wound and the number of beams on which the pile fibers are wound can be adjusted so that 600 to 1200 pile fibers are formed per 1m in the horizontal and vertical directions of the knit fabric after knitting.

[0070] After the warping process, a double Raschel warp knitting machine is used to knit a double Raschel warp knitted fabric in a structure where two knit fabrics are connected by pile fibers. A triple-structure devil Raschel warp knitted fabric is manufactured, consisting of two knit fabrics and a connecting layer between them.

[0071] After the knitting process, a sliding process is performed using a blade attached to the tip of the knitting needle at half the length of the pile fiber connecting the two knitted fabrics.

[0072] After the above slicing process, the pile fibers bonded to the knit fabric of the ground layer are separated into two by the cut pile fibers. After the slicing process, a heat treatment process is performed. Through the above heat treatment process, crimps are formed on the pile fibers bonded to the ground layer, and only then can the epidermal layer be completed.

[0073] The above heat treatment process can be performed at 100 to 170 ℃ for 1 to 10 minutes. By heat treating under these conditions, crimps can be formed on the pile fibers separated into two. If the heat treatment temperature is below 100 ℃, the heat treatment time must be long to achieve a very low crimp, and if the heat treatment temperature exceeds 170 ℃, the temperature is too high, causing the pile fibers to melt and potentially deteriorating the appearance of the epidermal layer. A higher heat treatment temperature results in a shorter heat treatment time, while a lower temperature results in a longer heat treatment time. Under the above conditions, fine crimps of 30 to 100 EA / inch can be formed on the pile fibers by heat treatment.

[0074] The epidermal layer can be dyed after heat treatment, or the yarn or pile fiber can be used as a dyed material.

[0075] The type of dye used in the process of dyeing the epidermal layer and the dyeing process may be disperse dyes capable of dyeing conventional polyethylene terephthalate fibers, and the dyeing process may apply conventional dyeing conditions capable of dyeing polyethylene terephthalate fibers with disperse dyes. Drying and heat treatment may be performed after dyeing.

[0076] Alternatively, an epidermal layer in which a pile layer of loops is connected to the ground layer of a knitted fabric can be manufactured using a tricot warp knitting machine. A warping process may be performed in which the yarn for forming the ground layer and the yarn for forming the loops are wound onto separate beams. After the warping process, the yarn for forming the ground layer is supplied to two bars and the yarn for forming the loops is supplied to one bar, and then knitting can be performed using a 3-bar tricot warp knitting machine. The two bars supplied with the yarn for forming the ground layer knit the ground layer fabric through the movement of a rotary machine, while the single bar supplied with the yarn for forming the loops forms the loops. This knitting method has the advantage of not requiring an additional process to attach loops to the knitted fabric forming the ground layer. The epidermal layer manufactured in this way can overcome problems such as loops being pulled out or fibers detaching due to friction that may occur during use. Furthermore, the above knitting method can provide a lightweight epidermal layer. At this time, the loops formed on the knit fabric can be formed in an amount of 600 to 1200 per 1m in the horizontal and vertical directions of the knit fabric, respectively, and the number of loops can be formed by adjusting the number of repetitions of two bars supplied with yarn for forming the ground layer and one bar supplied with yarn for forming the loops.

[0077] After the above knitting process, heat treatment, dyeing, drying after the dyeing process, and heat treatment may be performed. Accordingly, the conditions can be performed in the same way as the conditions for heat treatment, dyeing, drying after the dyeing process, and heat treatment performed after forming a pile layer on the knit fabric.

[0078] The method for manufacturing an automotive interior material according to the present invention (b) the step of forming a coating layer on the lower part of the manufactured surface layer can be performed by forming a coating layer using a VOC-free (Volatile Organic Compounds-free) foamed latex layer or a polypropylene resin.

[0079] The above latex layer can be integrated with the skin layer and the high-rigidity felt layer by melt-extruding the composition at 200 to 280°C, applying it to the underside of the skin layer, and drying it. Alternatively, the skin layer and the high-rigidity felt layer can be integrated by applying a composition containing polypropylene resin to the underside of the skin layer and drying it.

[0080] The composition forming the coating layer according to the present invention is the same as that described above, so a detailed description is omitted.

[0081] The method for manufacturing an automotive interior material according to the present invention includes the step of (c) forming a high-rigidity felt layer on the lower part of the coating layer.

[0082] The above high-rigidity felt layer is prepared by mixing or kneading 50 to 70 weight% of irregular cross-section fibers and 30 to 50 weight% of sheath-core PET fibers, followed by heating at 1 to 15 kg / cm² for 5 to 10 minutes at a temperature of 130 to 170 ℃. 2 By forming with pressure, the sheath portion, which is made of PET fibers with a sheath-core structure and has a low melting point, is fused to produce a high-rigidity felt layer.

[0083] The method for manufacturing an interior material for an automobile according to the present invention may further include the step of (d) extruding a foamed layer comprising a thermoplastic elastomer.

[0084] A composition comprising a thermoplastic elastomer, inorganic filler, and additives at a temperature of 60 to 150 ℃, 2 to 3 kg / cm² 2 A foamed layer extruded under pressure can be manufactured.

[0085] After steps (a) to (c) or (a) to (d) above, an interior material for an automobile floor or an automobile trunk trim can be manufactured by pressing with a pressure roller.

[0086] The basis weight of the automotive flooring material or interior material for an automotive trunk trim manufactured by the manufacturing method according to the present invention is 1,600 g / m² 2 It may be more than, or 1,700 g / 2 It may be greater than or equal to 1,800 g / m² 2 It may be greater than or equal to 1,900 g / m² 2 It may be more than that. Or the above knit fabric is 2,400 g / m 2 It may be less than or equal to 2,300 g / m² 2 It may be less than or equal to 2,200 g / m² 2 It may be less than or equal to 2,100 g / m² 2 It may be less than or equal to 1,600 to 2,400 g / m². Specifically, 1,600 to 2,400 g / m² 2 , 1,700 ~ 2,300 g / m 2 , 1,800 ~ 2,200 g / m 2 , 1,800 ~ 2,100 g / m 2 , 1,850 ~ 2,050 g / m 2 It could be.

[0088] In the following, embodiments of the present invention are further described with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are merely illustrative of the present disclosure and are not intended to limit the appended claims. It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope and spirit of the present disclosure, and that such variations and modifications fall within the scope of the appended claims.

[0090] Physical property evaluation

[0091] The NVH performance evaluation of the automotive interior material according to the present invention was performed by measuring the transmission loss value in accordance with ASTM E 1050 in the range of 400 to 10,000 Hz using the tube method. In this case, a higher transmission loss value indicates superior NVH performance.

[0093] (a) Step of manufacturing the epidermal layer

[0094] A yarn was prepared to form a knit fabric (ground layer) by winding a 225-denier multifilament, consisting of 75 strands of monofilament, onto a beam.

[0095] A side-by-side composite fiber with a weight ratio of 50:50 of PTT with an intrinsic viscosity of 0.98 and PET with an intrinsic viscosity of 0.42 was wound onto a beam to prepare a yarn for pile fibers.

[0096] After knitting, a beam wound with the prepared yarn and a beam wound with the pile fibers were prepared so that 600 to 1200 pile fibers were formed per 1m in the horizontal and vertical directions of the knit fabric (ground layer), respectively, and a double Raschel warp knitting machine was used to knit a double Raschel warp knitting fabric in which two knit fabrics are connected by pile fibers. After the knitting process, a sliding process was performed using a blade attached to the tip of the knitting needle at the halfway point of the length of the pile fiber connecting the two knit fabrics.

[0097] After the above sliding process, two pile fiber-shaped structures are manufactured by bonding them to the knit fabric (ground layer). Subsequently, the pile layer is manufactured by heat-treating them at 150°C for 3 minutes to develop 30 to 100 crimps / inch in the pile fibers.

[0098] From this, the basis weight including the pile layer bonded to the ground layer is 350 g / m² 2 The epidermal layer of was manufactured.

[0099] (b) Step of forming a coating layer

[0100] EVA (Hanwha Solutions product, vinyl acetate content 28.0 wt%, density 0.950 g / cm³) beneath the manufactured epidermal layer 3 A foam latex layer is foamed and then molded to a basis weight of 1000 g / cm³ 2 A foamed latex layer was formed.

[0101] (c) Step of manufacturing and laminating a high-rigidity felt layer

[0102] A sheet is prepared by mixing or kneading 50 wt% of irregular cross-section fibers and 50 wt% of sheath-core PET fibers (30 wt% sheath portion and 70 wt% core portion with a melting point of 120°C), and then subjected to a temperature of 140°C at 3 kg / cm² 2 Formed into a sheet shape under pressure, with a basis weight of 500 g / cm³ 2 A high-rigidity felt layer was manufactured.

[0103] After steps (a) to (c) above, an automotive floor material or an interior material for trunk trim was manufactured by pressing with a pressure roller.

[0104] In Example 1, the skin layer was manufactured such that the ground layer was a knitted fabric and the skin layer formed on the ground layer had loops formed as a pile layer, and the basis weight of the skin layer was 350 g / m² 2 Except for that, it was performed identically.

[0105] The same procedure was performed as in Example 1, except that an additional foam layer was included.

[0106] The foam layer can be manufactured as follows.

[0107] (d) step of extruding a foam layer containing a thermoplastic elastomer

[0108] 80 parts by weight of barium sulfate (average particle size 2.0㎛), 50 parts by weight of talc (average particle size 1.0㎛), and 50 parts by weight of calcium carbonate (average particle size 1.0㎛) were fed into the feeder for 100 parts by weight of a thermoplastic polyurethane elastomer (melt index ASTM D1238 (2.16kg, 205℃) 15 g / 10min) at the primary raw material input port of a twin-screw extruder (L / D=44, φ=32mm) heated to 215℃.

[0109] Subsequently, 2 parts by weight of carbon black (average particle size 20 nm), 0.5 parts by weight of antioxidant (IRGANOX1010), and 0.3 parts by weight of lubricant (PE Wax) were fed into the primary inlet located at the first stage of the twin-screw extruder, and the foamed layer composition was extruded into a sheet through a T-die via a 225°C hot melt mixing process. From this, the basis weight was 140 g / m² 2 A foamed layer was manufactured.

[0110] Comparative Example 1

[0111] The procedure was carried out in the same manner as in Example 1, except that the skin layer was made of a Bulked Continuous Filament (BCF) fabric (13 oz) knitted with nylon yarn.

[0112] Comparative Example 2

[0113] In Example 3, the procedure was performed in the same manner as in Example 3, except that the skin layer was made of a BCF (Bulked Continuous Filament) fabric (13 oz) (Comparative Example 1) knitted with nylon yarn.

[0114] Comparative Example 3

[0115] The epidermal layer of Comparative Example 1, with a basis weight of 120 g / m² at the bottom of the epidermal layer 2 A primary foam sheet, and a latex layer (100 g / m²) on the lower part of the primary foam sheet. 2 ), a PE coating layer formed on the lower part of the above latex layer with a composition including polyethylene resin (basis weight 200 g / m² 2An automotive interior material was manufactured comprising a foamed latex layer of Example 1 beneath the PE coating layer, a high-rigidity felt layer of Example 1 beneath the foamed latex layer, and a PU foam layer beneath the high-rigidity felt layer. The basis weight of the manufactured automotive interior material was 2,362 g / m². 2 It was.

[0116] Comparative Example 4

[0117] A coating layer (1,000 g / m²) prepared with a composition containing polypropylene resin on the lower part of the epidermal layer of Example 1 2 ), and backing nonwoven fabric (140 g / m² 2 An automotive interior material laminated with ) was manufactured. The basis weight of the automotive interior material manufactured at this time was 1,490 g / m² 2 It was.

[0119] Table 1 summarizes the characteristics of an automotive interior material manufactured from the manufacturing method according to the present invention.

[0120] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Basis weight (g / m²) 2 ) 1,850 1,850 1,990 1,969 2,109 2,362 1,490

[0121] Table 2 summarizes the physical properties and results evaluated after manufacturing the automotive interior material of Example 1 into a floor carpet.

[0122] item standard Test method Judgment criteria result Heat and cold resistance MS 210-05D Heat resistance 80±2℃, Cold resistance -40±2℃, Moisture resistance 50±2℃, 90% RH or higher There should be no visible changes such as twisting, deformation, discoloration, imbalance, fine cracks, peeling, hardness, or stickiness. OK (No change) Combustion resistance MS 300-08 After leaving the sample for at least 24 hours under conditions maintained at 16–21℃ and 55±5% relative humidity, leave it at 80±3℃ for 168 hours. The combustion speed must be 80 mm / min or less, or the combustion must not exceed 50 mm from the measurement point and must be extinguished within 60 seconds. OK(45 mm) durability MS 343-05 Wear Wheel: H-18 Load: 1kg on one side and applied to both sides (total 2kg) Wear Cycles: 300 times or more (TYPE-C) Must be Grade 3 or higher OK (Level 3) (500 times) VOC generation MS 300-34 DRY: Place the test specimen in a 4L desiccator, seal and heat, then remove the container and leave it at room temperature (23±2℃) for 60 minutes. Must be Grade 3 or higher OK (Level 3)

[0123] As can be seen from Table 2, the interior material of Example 1 had excellent heat and cold resistance, combustibility, durability, and suppression of VOC generation.

[0124] In addition, the interior material of Example 3 of the present invention has significantly superior sound absorption compared to the interior material of Comparative Example 2, and the sound insulation of Example 3 was at a level equivalent to or greater than that of Comparative Example 2 (Figs. 2, Fig. 3).

[0125] Accordingly, the automotive interior material according to the present invention is lightweight, has excellent water absorption and sound insulation properties, and exhibits excellent heat and cold resistance, flammability, durability, and suppression of VOC generation, making it suitable for application in electric vehicles.

[0127] The present invention is not limited by the embodiments described above, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, and such are also to be considered to fall within the scope of the present invention.

Claims

Claim 1 A lightweight interior material for automobiles comprising: a skin layer including a ground layer and a pile layer; a coating layer laminated below the skin layer; and a high-rigidity felt layer laminated below the coating layer, wherein the pile layer comprises a side-by-side composite fiber in which a polytrimethylene terephthalate (PTT) resin having an intrinsic viscosity of 0.96 to 1.20 and a polyethylene terephthalate (PET) resin having an intrinsic viscosity of 0.40 to 0.55 are combined in a weight ratio of 45:55 to 55:45, and the composite fiber has a crimp of 30 to 100 EA / inch. Claim 2 A lightweight interior material for automobiles according to claim 1, further comprising a foam layer below the high-rigidity felt layer. Claim 3 In claim 1, the ground layer is a lightweight interior material for automobiles made of knit fabric. Claim 4 In paragraph 3, the above-mentioned surface layer is formed by combining fiber piles or loops with a knitted fabric, a lightweight interior material for automobiles. Claim 5 In paragraph 4, the above-mentioned combination is a lightweight interior material for automobiles produced by a double raschel warp knitting machine or a tricot warp knitting machine. Claim 6 In paragraph 3, the above knit fabric is a lightweight interior material for automobiles, which is a knit fabric knitted from polyethylene terephthalate filaments. Claim 7 In paragraph 4, the fiber pile is composed of 100% polyester fibers, a lightweight interior material for automobiles. Claim 8 In claim 1, the coating layer comprises a polyethylene terephthalate resin, a polybutylene terephthalate resin, a polyethylene vinyl acetate resin, or a polyurethane resin, a lightweight interior material for automobiles. Claim 9 In paragraph 2, the foam layer comprises a thermoplastic elastomer, making it a lightweight interior material for automobiles.

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