KR20230078840A - Bio-recycling complex interior material for vehicles - Google Patents

Abstract

The present invention relates to a method for manufacturing an interior material for a vehicle, which is eco-friendly by applying natural fibers and regenerated fibers, implements light weight, increases sound absorption and shock absorption, and improves stiffness, breaking strength and flexural elasticity. It relates to a method for manufacturing composite interior materials.
The present invention comprises the steps of "(a) mixing and kneading natural fibers and synthetic fibers to form a non-woven felt layer; (b) forming a composite film layer in which a polypropylene-based/polyethylene-based composite film is heated and pressed on one side or both sides of the non-woven felt layer to manufacture a multi-layered laminated board; (c) preheating and shaping the laminated board by heating and pressing it with a temporary mold; and (d) molding the preheated and temporarily molded laminate board into a final product shape by pressing it at room temperature with a final molding mold. It provides a method for manufacturing bio-regenerated composite interior materials for vehicles comprising a.

Description

Manufacturing method of bio-recycling complex interior material for vehicles {Bio-recycling complex interior material for vehicles}

The present invention relates to a method for manufacturing an interior material for a vehicle, which is eco-friendly by applying natural fibers and regenerated fibers, realizes light weight, increases sound absorption and shock absorption, and improves stiffness, breaking strength and flexural elasticity. It relates to a method for manufacturing composite interior materials.

Recently, products using eco-friendly materials, including biocomposite materials, are being developed in various fields such as buildings, automobiles, and electronic parts materials. Biocomposite materials such as biodegradable plastics and biomass-based plastics with reinforced mechanical strength have been actively developed to replace plastics. In particular, Europe and the United States are trying to increase the use of biocomposite materials through environmental regulations, such as legalizing the use of biodegradable materials for all automobile parts and materials sold in their countries. Parts that mainly use biocomposite materials in automobiles include headlining, door trim, vehicle interior flooring, ceiling interior materials, and center fascia interior materials. In particular, interior materials using natural fibers are mainly being developed.

In addition, as the depletion of resources and pollution of the environment by waste intensify, there is an increasing demand for the spread and application of low-carbon policies throughout the industry worldwide and the recycling of resources. Research on the discovery of renewable materials and the use of recycled materials is also active. it is progressing Recycled materials are economical because they can be produced at a lower price than conventional materials while protecting the environment by reducing the emission of waste.

In particular, when producing 100 ton of synthetic fiber in a textile factory, about 10 ton of polyester and nylon fiber by-products were generated, and about 10% of the total amount of synthetic fiber was discarded. This causes very serious cost and environmental problems, and the polyester and nylon fiber by-products are treated as industrial waste, which causes environmental pollution and processing costs due to waste, so research on recycling methods is urgent.

As automotive parts are directly related to the driver's life safety, securing sufficient mechanical strength is of utmost importance. Therefore, development of products with performance equivalent to the quality, functionality and durability of existing petroleum-based plastics (PP-based, ABS-based, etc.) is essential. It is essential, and biocomposite materials including vegetable fibers have strengths such as lightness, securing mechanical strength, securing relatively high impact strength, and ease of processing, assembly, and molding.

In general, natural fiber composite materials refer to biodegradable fibers as composite fibers including fibers derived from plants and animals. In the past, when only natural fibers were used, it was difficult to express the strength of conventional petroleum-based plastics, so in order to secure sufficient mechanical strength, it was mixed with thermoplastic polypropylene fibers to produce a biocomposite material. More specifically, in the past, a natural fiber felt web sheet (non-woven fabric) manufactured by needle punching after mixing natural fiber and synthetic fiber at a ratio of 50:50% is sprayed or impregnated with a thermosetting resin to make a laminated board. The thermosetting binder was molded and molded into automotive interior parts such as door trim.

However, the laminated board manufactured by spraying or impregnating the thermosetting resin as described above has a weak bonding force between the natural fiber felt web sheet and the thermosetting resin having a large number of voids, resulting in separation between the material layers, which reduces the overall strength of the interior material. will come

In addition, the felt web sheet (non-woven fabric) formed by mixing natural fibers and synthetic fibers is difficult to uniformly mix materials due to the difference in physical properties between natural fibers and synthetic fibers, and the elongation of natural fibers is insufficient during mixing, resulting in deep steps. When working with a mold, the member breaks or ruptures due to the lack of elongation of natural fibers, so there are problems such as bursting, tearing, and material separation of the interior material when forming a mold with a complicated shape or an edge or a severely curved part.

In addition, when natural fibers are applied, the smell due to carbonization of natural fibers and the unique odor of raw materials of natural fibers are generated during thermoforming, and preservative treatment is performed to suppress the decay of natural fibers, the occurrence of bacteria and fungi. There was a concern about the release of harmful components by chemicals used for the process of applying natural fibers.

In addition, when the felt layer and the thermosetting resin are combined, the separation of the materials occurs frequently due to the difference in physical properties of the materials, resulting in a decrease in the overall strength of the interior material, and the shock absorption and absorption properties due to the difference in elongation between the thermosetting resin and the felt layer. , sound insulation may deteriorate.

In addition, there is a disadvantage in that the thickness of the felt layer is significantly reduced in the process of pressurizing the natural fiber/thermosetting binder into the mold, thereby degrading the bending characteristics.

In addition, among natural fibers, vegetable fibers are composed of cellulose, hemicellulose, lignin, pectin, and wax. Among them, hemicellulose and lignin excluding cellulose (lignin), pectin (pectin), and wax (wax) correspond to impurities that deteriorate the properties of processes or products. Low-purity vegetable fibers that have not undergone a precise refining process reduce adhesion to synthetic fibers and deteriorate overall physical properties due to corruption of impurities. Therefore, the quality of vegetable fibers is determined by whether or not the impurities are sufficiently removed, and an optimized treatment method for impurities is additionally required to produce vegetable fibers of excellent quality.

1. Registered Patent No. 10-1027989 "Vehicle interior material using natural fibers" 2. Registered Patent No. 10-1726164 "Manufacturing method of automobile interior materials using natural fiber composite materials" 3. Registered Patent No. 10-1755850 "Sound absorbing material for automobile interior using recycled fiber and its manufacturing method" 4. Registered Patent No. 10-1729083 "Bio sheet for automobile interior materials"

The present invention is environmentally friendly and lightweight by applying natural fibers and regenerated fibers, and heat-presses a nonwoven felt layer and a composite film to which refined natural fibers are applied, thereby preventing separation of materials, realizing weight reduction, sound absorption and impact An object of the present invention is to provide a method for manufacturing a bio-regenerated composite interior material for a vehicle that increases absorbency and improves stiffness, breaking strength and flexural elasticity.

The present invention comprises the steps of "(a) mixing and kneading natural fibers and synthetic fibers to form a non-woven felt layer; (b) forming a composite film layer in which a polypropylene-based/polyethylene-based composite film is heat-compressed on one side or both sides of the non-woven felt layer to manufacture a multi-layered laminated board; (c) preheating and shaping the laminated board by heating and pressing it with a temporary mold; and (d) molding the preheated and temporarily molded laminate board into a final product shape by pressing it at room temperature with a final molding mold. It provides a method for manufacturing bio-regenerated composite interior materials for vehicles comprising a.

Natural fibers of the non-woven felt layer may be applied by refining at least one of Kenyap and Abaca.

In addition, the synthetic fibers of the non-woven felt layer may include at least one of high-tenacity polyester and high-tenacity nylon, while using a by-product of a textile factory process.

In addition, natural fibers and synthetic fibers of the non-woven felt layer may be mixed in a ratio of 40 to 50% natural fibers and 50 to 60% synthetic fibers.

In addition, the composite film layer may be formed in an amount of 200 to 300 g/m ² .

In addition, in the step (c), the laminated board may be heat-compressed by pressing at a heating temperature of 180 to 200 ° C. for 120 to 160 seconds.

According to the present invention, the following effects can be expected.

1. Eco-friendly and economical by applying natural and regenerated fibers.

2. By using refined natural fibers, bonding strength with synthetic fibers is improved, impurities are removed to increase the physical properties of natural fibers, natural fibers are uniformly dispersed in the non-woven felt layer when mixed, and thermal stability is excellent. During the heating process, generation of harmful gas, odor and discoloration can be suppressed.

3. By heating and pressing the non-woven felt layer and the composite film using a hydraulic heat press, the physical properties of the laminated structure are increased by being firmly coupled to each other and increasing integrity compared to a laminated board manufactured by conventional spraying or impregnation of synthetic resin.

4. By heat-pressing the non-woven felt layer and the composite film to which natural fibers are applied, the density of the member is increased, thereby increasing the absorbency and shock absorption while realizing aging, and improving the physical properties of the member.

5. By applying a composite film in which thermoplastic polypropylene-based/polyethylene-based films are laminated, the bonding force with the non-woven felt layer is superior to that of the existing thermosetting resin layer, and the stiffness, tensile strength, breaking strength, and flexural elasticity are increased.

[Figure 1] shows a manufacturing process using a hot compression press and a room temperature compression press used in any one or more of steps (b) to (d) of the present invention.
[Figure 2] shows the surface state of the front and rear surfaces of the polypropylene-based/polyethylene-based composite film layer of the present invention.

In the present invention, a laminated board is prepared by heat-pressing a polypropylene/polyethylene-based composite film on one side or both sides of a nonwoven felt layer in which natural fibers and synthetic fibers are mixed and kneaded, and then the laminated board is heated and pressed to form a temporary mold, It consists of a process of pressing the temporarily molded laminated board at room temperature and molding it into a final product shape.

The present invention comprises the steps of "(a) mixing and kneading natural fibers and synthetic fibers to form a non-woven felt layer; (b) forming a composite film layer in which a polypropylene-based/polyethylene-based composite film is heat-compressed on one side or both sides of the non-woven felt layer to manufacture a multi-layered laminated board; (c) preheating and shaping the laminated board by heating and pressing it with a temporary mold; and (d) molding the preheated and temporarily molded laminate board into a final product shape by pressing it at room temperature with a final molding mold. It provides a method for manufacturing bio-regenerated composite interior materials for vehicles comprising a.

Hereinafter, each step of the process of the present invention will be described in detail.

1. Step (a)

Step (a) is a step of forming a nonwoven felt layer by mixing and kneading natural fibers and synthetic fibers. The natural fiber is applied by refining at least one of Kenyap and Abaca, and the synthetic fiber may include at least one of high-tenacity polyester and high-tenacity nylon. Natural fibers and synthetic fibers of the non-woven felt layer may be mixed in a ratio of 40 to 50% natural fibers and 50 to 60% synthetic fibers.

Natural fibers mixed in the non-woven felt layer are preferably vegetable fibers such as Kenaf or Abaca, which are inexpensive and have high tensile strength and elastic modulus, and have excellent processability, or a mixture thereof.

Natural plant fibers such as Kenyap and abaca are composed of impurities such as hemicellulose, lignin, pectin, and wax in addition to cellulose. Cellulose is a backbone that maintains the physical properties of fibers and cell stability, and removes impurities other than cellulose. If this is not done, there is a risk that odors due to carbonization of natural fibers may occur during the heating process, and corruption of natural fibers, bacteria and mold may occur. In general, preservative treatment is performed to suppress this, but there is a disadvantage in that harmful components resulting from the preservative are generated, and odors peculiar to the preservative and materials are generated.

Therefore, it is preferable to separately refine at least one of Kenyap and Abaca in order to remove impurities other than cellulose to improve mechanical properties and at the same time to remove odor.

The scouring process of the vegetable natural fiber is preferably refined by heating to 70 to 90 ° C. in the presence of an amylase enzyme to refine the fineness to a fineness of 3 to 4.5 denier. Specifically, 0.1 to 1% by weight (preferably 0.3 to 0.6% by weight) of amylase enzyme relative to 100% by weight of natural fiber is added to a batch-type circular drum bath, followed by heating at room temperature to 70 to 90 ° C for purification. can do. Accordingly, impurities such as lignin, pectin, and wax (lipid) contained in the vegetable natural fibers are purified, and the intrinsic fineness of the vegetable fibers is reduced from 10 to 15 denier to 3 to 4.5 denier. There is an effect of improving the fiber binding force per unit density at the time of manufacturing the felt layer.

The natural fibers to which the refined Kenyap and Abaca are applied have excellent bonding strength with synthetic fibers, and can be uniformly dispersed in the nonwoven felt layer because entanglement, jamming, and adhesion due to impurities do not occur when mixing the fibers. In addition, since the refined cellulose has stable cells and increases mechanical strength and thermal stability, odor and discoloration due to carbonization of fibers do not occur during the heat-pressing process.

In summary, in the present invention, the applied refined natural fibers improve bonding strength with synthetic fibers, increase the physical properties of natural fibers by removing impurities, ensure that natural fibers are uniformly dispersed in the nonwoven felt layer when mixed, and have thermal stability. This is excellent and has the effect of suppressing the occurrence of harmful gases, odors and discoloration during the heating process.

The synthetic fiber may include at least one of high tenacity polyester and high tenacity nylon.

In the present invention, the use of eco-friendly materials is the core of the technical content, and generally applied thermosetting resins (phenol resins, epoxy resins, melamine resins, urea resins, alkyd resins, silicon resins, polyurethane resins, acrylic resins, amino resins, etc.) And other materials such as glass fiber, mineral fiber, talc, calcium carbonate, and carbon fiber are not applicable due to the possibility of generating harmful gases and harmful substances during manufacturing.

In addition, the synthetic fibers of the non-woven felt layer may include at least one of high-tenacity polyester and high-tenacity nylon, while using a by-product of a textile factory process.

The physical properties of high-tenacity polyester and high-tenacity nylon applied in the present invention are shown in [Table 1].

tensile strength
( cN / dtex ) Shinto
(%) importance process
Moisture rate
(%) thermal properties health wet strength humidity and dryness softening
temperature melting
temperature high strength polyester (PET) 7.8~8.1 5.1~6.7 35 to 50 1.38 0.4 238~240 255 to 260 High tenacity nylon (nylon 66) 8.5 to 9.0 8.5 to 9.0 32~45 1.18 4.3 230~235 250-260 nylon 6 4.2~5.6 4.2~5.6 28-43 1.14 4.5 180 215 to 220 polypropylene 4.0 to 6.6 4.0 to 6.6 30 to 60 0.91 0 140 to 160 165~173 polyethylene 4.4~7.9 4.4~7.9 8 to 35 0.95 0 100 to 115 125 to 135

The above [Table 1] shows the physical properties of staple fibers applied to the present invention, and has high tensile strength and elongation and excellent thermal stability compared to general synthetic fibers. At this time, since the high-strength polyester and the high-tenacity nylon have melting points in the range of 230-240° C., it can be confirmed that the thermal stability is excellent even when the materials are mixed.

The mixing and kneading process of natural fibers and synthetic fibers is preferably performed through a needle punching process. The needle punching process is a method of vertically punching a fiber mixture with a plurality of needles to create an integrated fiber structure. The needle punching process simplifies the manufacturing process of the nonwoven felt layer and forms the nonwoven felt layer to a predetermined thickness It is desirable to be able to

In addition, a plurality of nonwoven felt layers produced by needle punching are laminated to increase the thickness of the nonwoven felt layer to form a nonwoven felt layer (multi-layer web) having a higher thickness than the nonwoven fabric layer applied to the existing vehicle interior material.

The synthetic fiber applied to the nonwoven felt layer is preferably formed in a length of 65 to 72 mm and has a fineness of 1 to 3 denier. Fibers applied to general non-woven fabrics use fibers with a length of 50 to 55 mm, but in the present invention, long fibers with a length of 65 to 72 mm are mixed to increase the kneading rate and bonding force with natural fibers to increase the strength of the non-woven felt layer. can make it

To describe the process of the non-woven felt layer in more detail, the crimp-free fiber fibers are cut to a length of 65 to 72 mm to increase the bonding strength between materials, and the fibrillation operation is performed in the fibrillation cylinder of the fibrillation machine, and the fibrillated fibers are After a mixing/opening step in which uniform dispersion and mixing is performed by a disperser, the mixed/opened fibers are subjected to a fronting machine to improve physical properties such as tensile strength and impact strength. The mixed/opened fibers are formed into a fibrous thin web while passing through a cylindrical cylindrical carding machine, and a multi-layered web is formed through a doubling step of overlapping these fibrous thin webs in several layers. Therefore, the multi-layered web is transferred to a needle punching device via a pressure roller on a transfer belt, and a nonwoven fabric is manufactured by needle punching. In the needle punching device, the thickness and density of the supplied nonwoven felt layer can be adjusted, and a nonwoven felt layer having a uniform thickness can be formed through needle punching.

Natural fibers and synthetic fibers of the non-woven felt layer may be mixed in a ratio of 40 to 50% natural fibers and 50 to 60% synthetic fibers. It is preferable to mix natural fibers and synthetic fibers in a ratio of 50:50, and up to 60% of synthetic fibers, to the extent that the biodegradability of natural fibers is not impaired and the physical properties such as tensile strength and abrasion resistance of the nonwoven felt layer are not impaired. can be mixed. When the mixing ratio of the synthetic fiber is 40% or less, the physical properties of the nonwoven felt layer may deteriorate.

2. Step (b)

In step (b), a laminated board having a multi-layer structure may be manufactured by forming a composite film layer obtained by heat-pressing a polypropylene-based/polyethylene-based composite film on one side or both sides of the nonwoven felt layer.

It is preferable to form a laminated board by heat-pressing a polypropylene-based/polyethylene-based composite film on the non-woven felt layer.

The process of forming a laminated board of non-woven fabric/thermosetting resin applied to existing vehicle interior materials is to combine the non-woven fabric layer and the thermosetting resin by spraying or impregnating the thermosetting resin at room temperature, and problems such as material separation and strength reduction have occurred due to the weak bonding force between the materials. The present invention can prevent material separation by the heat pressing process.

As shown in [FIG. 1], the heat compression process may proceed with a flat plate compression process using a 250 to 300 ton hydraulic hot press equipment.

The composite film layer is heat-pressed and bonded to one side or both sides of the non-woven felt layer, thereby protecting the non-woven felt layer and improving strength. The composite film layer may be coupled to one side or both sides of the non-woven felt layer, but if the non-woven felt layer is directly exposed inside the vehicle, the non-woven felt layer may be damaged or the non-woven felt layer may be contaminated by dust, moisture, etc. Since there is a possibility, it is preferable to construct a composite film layer on the inside that is in direct contact with the inside of the vehicle.

The composite film layer is a composite of polypropylene-based/polyethylene-based resin, and the composite film layer may be configured as in the example shown in Table 2 below.

item Measures How to measure details One thickness
(cross-section photo) 3-Layer : 64.6 ㎛ (polypropylene layer) 2-Layer : 40.4 ㎛ (polyethylene layer) 1-Layer : 51.5 ㎛ (polypropylene layer)

2 tensile strength
/elongation rate
(MD/TD) width Tensile strength: 27.035 kgf/mm ²
Elongation: 25.85% length Tensile strength: 243.52 kgf/cm ²
Elongation: 766.4%

The composite film layer is preferably composed of a total of three layers as shown in [Table 2] due to the increase in physical properties and the difference in characteristics of each material.

Polypropylene (PP) and polyethylene (PE) are thermoplastic resins, both of which have excellent compatibility, are non-toxic, do not generate polluting gases, are chemically stable, and have excellent corrosion resistance and chemical resistance.

Polyethylene (PE) has excellent flexibility, elongation, impact strength, and permeability, and polypropylene (PP) has excellent strength, hardness, and heat resistance, so polypropylene (PP) and polyethylene (PE) are classified as shown in Table 2. When formed as a laminated composite structure, it has excellent ductility and rigidity. Since polyethylene (PE) has lower strength and heat resistance than polypropylene (PP), it is preferable to protect the polyethylene (PE) by laminating the polypropylene (PP) on the upper and lower layers of the polyethylene (PE).

As described above, the non-woven felt layer, the synthetic fibers, and the synthetic fibers of the composite film layer are all formed of thermoplastic resins and have excellent bonding properties by hot pressing. The composite film layer is bonded while melting and permeating the surface of the non-woven felt layer at least 20% of the total weight during thermoforming to increase the bonding strength with the non-woven felt layer and at the same time increase the strength of the non-woven felt layer, thereby increasing the overall laminated board. Tensile strength and flexural strength can be increased.

The composite film layer may be formed in an amount of 200 to 300 g/m ² . When the thickness of the composite film layer is less than 200 g/m ² , the thickness of the fusion bonded part is not sufficient, and when it exceeds 300 g/m ² , weight and cost increase due to excessive use of materials compared to increase in strength.

3. Steps (c) and (d)

In step (c), the laminated board is preheated and temporarily molded by heating and pressing the laminated board with a temporary mold, and in step (d), the preheated and temporarily molded laminated board is pressed at room temperature with a final molding mold to form a final product shape. there is.

In addition, in the step (c), it is preferable to heat-press the laminated board by pressing for 120 to 160 seconds at a heating temperature of 180 to 200 ° C. in consideration of the melting points of natural fibers and synthetic fibers in the preheating and temporary molding operations. .

As described above, the heating temperature is to prevent natural fibers from being deformed by heat, and heat-compression is performed at a relatively low temperature in the range of 180 to 200 ° C for 120 to 160 seconds to prevent cell destruction of natural fibers, thereby reducing physical properties of interior materials. It can be prevented.

After the preheating and temporary molding steps, in the final product shape forming step, the temporarily formed laminated board is taken out, transferred to a final molding mold, and pressed at room temperature to form a final product.

<Example>

In the test example of [Table 3] below, the ratio of natural fibers and synthetic fibers in the non-woven felt layer is 50:50, and thermoplastic polypropylene/polyethylene film composite films of 200 g/m ² weight are laminated on both sides of the non-woven felt layer. A fiber composite material was used and heat-compressed at 190°C for 1 minute and 10 seconds. In order to confirm the strength and light weight of the product manufactured according to the examples, two types of test specimens were prepared and the flexural strength and burst strength were measured and compared with existing products.

Comparative Example is a general nonwoven fabric, Example 1 is an example in which Kenyap and high-tenacity nylon are mixed, and Example 2 is an example in which abaca and high-tenacity poling ester are mixed.

unit comparative example Example 1 2 in implementation weight g/m ² 1200 1270 1400 tensile strength
MPa MD 12 MD 38.6 MD 47 CD 11 CD 47.5 CD 56.8 bursting strength MPa MD 10 MD 21.2 MD 40.4 CD 9 CD 29.5 CD 25.2 Whether or not there is an explosion burst occurrence no bursting no bursting Heat pressing conditions 190℃, 1 minute 10 seconds Mixed Composition Ratio General PP non-woven fabric Kenyan 50%,
45% high tenacity nylon Abaca 50%
50% high tenacity polyester

As a result of the tests of Comparative Example 1 and Examples 1 and 2, it was confirmed that the strength of the vehicle interior material manufactured according to the present invention was superior to that of the case where a general nonwoven fabric was applied, and it was confirmed that no bursting occurred.

Although the present invention has been described in relation to the test examples as mentioned above, various modifications and variations are possible within the scope without departing from the gist of the present invention, and can be used in various fields. Accordingly, the claims of the present invention include modifications and variations that fall within the true scope of the foregoing invention.

Not applicable

Claims (6)

(a) mixing and kneading natural fibers and synthetic fibers to form a nonwoven felt layer;
(b) forming a composite film layer in which a polypropylene-based/polyethylene-based composite film is heated and pressed on one side or both sides of the non-woven felt layer to manufacture a multi-layered laminated board;
(c) preheating and shaping the laminated board by heating and pressing it with a temporary mold; and
(d) molding the preheated and temporarily molded laminated board into a final product shape by pressing it at room temperature with a final molding mold;
Bio-regeneration composite interior material manufacturing method comprising a.
In paragraph 1,
The natural fiber of the non-woven felt layer is a method for manufacturing a bio-regenerated composite interior material for a vehicle, characterized in that at least one of Kenyap and Abaca is refined and applied.
In paragraph 1,
The synthetic fiber of the non-woven felt layer uses a by-product of the textile factory process,
A method for manufacturing a bio-regenerated composite interior material for a vehicle, characterized in that it comprises at least one of high-strength polyester and high-tenacity nylon.
In paragraph 1,
Natural fibers and synthetic fibers of the non-woven felt layer are mixed in a ratio of 40 to 50% of natural fibers and 50 to 60% of synthetic fibers.
In paragraph 1,
The composite film layer is a vehicle bio-regeneration composite interior material manufacturing method, characterized in that formed in an amount of 200 ~ 300 g / m ² .
In paragraph 1,
In step (c), the bio-regeneration composite interior material manufacturing method for a vehicle, characterized in that the laminated board is heated and pressed by pressing at a heating temperature of 180 to 200 ° C. for 120 to 160 seconds.

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