WO2024144081A1 - Eco-friendly multilayered sheet composed of natural fiber-based blended non-woven fabric layer and polyolefin resin layer - Google Patents

Abstract

The present invention relates to a multilayered sheet in which a polyolefin resin film or sheet layer with thickness of 0.1-3 mm obtained by melt-extrusion of a polyolefin resin under 250-350°C is combined and stacked on one or both surfaces of a non-woven sheet which is a blend of synthetic fibers, and hollow or non-hollow natural fibers of 0.5-10 mm thickness supplied from a T-die extruder. The multilayered sheet according to the present invention is eco-friendly due to the inclusion of natural fibers that is carbon-neutral while having excellent mechanical properties and low odor, and can be advantageously used as automobile interior material, such as for instrument panels, door trims, interior trims, ceilings, or car seats.

Description

Eco-friendly multi-layer sheet composed of natural fiber blended non-woven fabric layer and polyolefin resin layer

The present invention relates to an eco-friendly multilayer sheet composed of a natural fiber-based blended nonwoven fabric layer and a polyolefin resin layer.

As global warming caused by carbon dioxide emissions becomes more serious around the world, efforts to achieve carbon neutrality are being made in various fields to solve this problem.

In the case of plants, they are called carbon-neutral materials because they absorb a large amount of carbon dioxide present in the atmosphere and emit oxygen during the process of cultivation and growth. In this regard, plant natural fibers are added to synthetic resins as much as possible while maintaining excellent mechanical properties. The development of carbon-neutral, eco-friendly material manufacturing technology for added automobile interior materials is actively underway.

Recently, a mixture of incompatible hydrophilic bamboo short fibers (natural fibers) and hydrophobic polypropylene resin with maleic anhydride grafted polyolefin resin as a compatibilizer was compounded in an extruder to create a natural fiber-reinforced eco-friendly composite material suitable for automobile interior materials. Although there is research into manufacturing,

For example, as in Republic of Korea Patent No. 10-0941269, a mixture of incompatible hydrophilic bamboo short fibers (natural fibers) and hydrophobic polypropylene resin with maleic anhydride grafted polyolefin resin as a compatibilizer is compounded in an extruder to manufacture automobiles. An attempt was made to manufacture an eco-friendly composite material reinforced with natural fibers suitable for interior materials, but natural fibers are easily carbonized due to friction and high heat between the kneader blade for dispersion and the cylinder for dispersion during compounding and between the extruder screw and the cylinder, resulting in deterioration of mechanical properties and serious odor generation. There is a problem, especially its application to automobile interior materials that are sensitive to odors and volatile organic compounds (VOCs).

Accordingly, for example, as in Republic of Korea Patent Registration No. 10-1543597, a first step of manufacturing felt from a mixture of natural fibers and thermoplastic polymer fibers among composite materials; A method of manufacturing a sheet suitable for automobile interior materials was presented by a second step of spraying or applying liquid isocyanate on the surface of the felt and hot pressing and curing the felt sprayed with the liquid isocyanate. According to this method, the kneader during compounding It has the advantage of avoiding carbonization of natural fibers caused by friction and heat between blades and cylinders, and between extruder screws and cylinders, and of securing excellent mechanical properties. However, the manufacturing process is complex, which increases manufacturing costs significantly, and unreacted liquid isocyanate is used. The odor and VOCs generated from the residue are so serious that it cannot be commercialized in reality.

Therefore, it is urgent to develop a new technology for manufacturing eco-friendly materials containing natural fibers suitable for automobile interior materials that minimize thermal decomposition of natural fibers due to friction and heat, maintain excellent mechanical properties, have low manufacturing costs, and dramatically reduce odor.

Meanwhile, when a 10% "lightweight" is achieved in a car, fuel efficiency increases by 3.8%, acceleration increases by 8%, chassis durability increases by 1.7 times, steering ability improves by 6%, braking distance is shortened by 5%, and exhaust gases are reduced, etc. As dramatic changes occur, the development of lightweight technology is a megatrend in the global automobile industry.

In particular, in the case of electric vehicles, which are gradually becoming a recent megatrend, there is a growing trend to adopt interior materials using carbon-neutral, eco-friendly materials that are lightweight even if the cost is slightly higher. As a result, the development of such materials is actively underway around the world. is still insignificant.

Ultimately, there is a desire for the emergence of groundbreaking new materials that can achieve a carbon-neutral effect through the use of natural fibers and at the same time reduce weight, and the emergence of automobile interior materials manufactured from them, which is very urgent and desperate.

The present invention seeks to provide a multilayer sheet that has excellent mechanical properties and low odor while being eco-friendly due to the natural fiber contained in it, which is a carbon-neutral material.

In addition, the present invention seeks to provide a multilayer sheet suitable for lightweight automobile interior materials that has excellent lightweight properties, excellent mechanical properties, low odor, and eco-friendliness.

The present invention relates to an eco-friendly multilayer sheet composed of a natural fiber-based blended nonwoven fabric layer and a polyolefin resin layer.

More specifically, it is a multi-layer sheet in which a polyolefin resin film or sheet layer is laminated on a non-woven fabric sheet blended with natural fibers and synthetic fibers by melt extrusion under specific conditions, and is a neutral carbon material that has excellent mechanical properties and low odor. This relates to a multi-layer sheet suitable for automobile interior materials that is environmentally friendly using natural fibers.

In addition, the present invention relates to a multi-layer sheet suitable for lightweight automobile interior materials that has excellent mechanical properties, low odor, and eco-friendliness as well as excellent lightness by using hollow natural fibers among the natural fibers.

In the present invention, polyolefin resin is melt-extruded under conditions of 250 to 350°C on one or both sides of a nonwoven fabric sheet mixed with natural fibers and synthetic fibers with a thickness of 0.5 to 10 mm supplied from a T-die extruder to produce a polyolefin resin film or The object is to provide a multi-layer sheet in which sheet layers are combined and laminated.

According to one aspect of the present invention, the natural fiber may include hollow natural fiber or non-hollow natural fiber.

According to one aspect of the present invention, the hollow natural fiber may include kapok fiber.

According to one aspect of the present invention, the non-hollow natural fiber is one selected from the group consisting of cotton, cotton, flax, hemp, hemp, jute, sheep hemp, sarago, cyral, maguey, buntal, raffia, and enegen. It may include more than just that.

According to one aspect of the present invention, the synthetic fiber may include one or more selected from the group consisting of polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers.

According to one aspect of the present invention, the synthetic fiber may be a core-sheath type composite yarn.

According to one aspect of the present invention, the polyolefin resin is a group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, and polybutene. It may include one or more selected from.

According to one aspect of the present invention, a polyolefin resin containing a maleic anhydride group or an epoxy group may be further added to the polyolefin resin.

According to one aspect of the present invention, a quaternary ammonium salt or a quaternary phosphonium salt may be further added to the polyolefin resin.

According to one aspect of the present invention, polyolefin elastomer may be further added to the polyolefin resin.

According to one aspect of the present invention, one or more selected from the group consisting of inorganic fillers, lubricants, antioxidants, heat resistant agents, ultraviolet absorbers, antistatic agents, and deodorants may be further added to the polyolefin resin.

According to one aspect of the present invention, the inorganic filler may be one or more selected from the group consisting of talc, calcium carbonate, silica, kaolin, alumina, wollastonite, sepiolite, zonotolite, titanium dioxide, and glass fiber.

According to one aspect of the present invention, the blended nonwoven sheet may further include a woven or knitted sheet.

According to one aspect of the present invention, the polyolefin resin film or sheet layer may have a thickness of 0.1 to 3 mm.

According to one aspect of the present invention, an eco-friendly automobile interior material obtained by placing the multilayer sheet in a mold of a certain shape and heat compression can be provided.

According to one aspect of the present invention, an eco-friendly automobile interior material obtained by placing the multilayer sheet in a mold of a certain shape, preforming by heat compression, and rear-injecting a polyolefin resin can be provided.

According to one aspect of the present invention, a blended nonwoven fabric sheet made by blending natural fibers and synthetic fibers; and applying molten polyolefin resin to one or both sides of the blended nonwoven fabric sheet and extruding it with a T-die extruder. A method of manufacturing a multilayer sheet in which polyolefin resin films or sheet layers are bonded and laminated, including: The natural fiber has a thickness of 0.5 to 10 mm, and the melting temperature of the polyolefin resin melted in the T-die extruder is 250 to 350 ℃.

According to one aspect of the present invention, the extrusion temperature of the T-die extruder may be 290 to 340 ° C.

According to one aspect of the present invention, the extrusion temperature of the T-die extruder may be 300 to 330 ° C.

According to one aspect of the present invention, the natural fiber may include hollow natural fiber or non-hollow natural fiber.

According to one aspect of the present invention, the synthetic fiber may include one or more selected from the group consisting of polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers.

According to one aspect of the present invention, the polyolefin resin is a group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, and polybutene. It may include one or more selected from.

According to one aspect of the present invention, one or more selected from the group consisting of inorganic fillers, lubricants, antioxidants, heat resistant agents, ultraviolet absorbers, antistatic agents, and deodorants may be further added to the polyolefin resin.

The multilayer sheet according to the present invention is a multilayer sheet in which a polyolefin resin film or sheet layer is laminated on a nonwoven fabric sheet mixed with natural fibers and synthetic fibers by melt extrusion under specific conditions, and has excellent mechanical properties and low odor while containing carbon. It is eco-friendly due to natural fiber, a neutral material, and can be usefully used as automobile interior materials such as instrument panels, door trims, interior trims, ceiling materials, and car seats.

In addition, when hollow natural fibers are used among the natural fibers, they have excellent lightness, excellent mechanical properties, low odor, and are eco-friendly, making them suitable for lightweight automobile interior materials.

1 is a cross-sectional SEM image of an example of a multilayer sheet not according to the present invention.

Figure 2 is a cross-sectional SEM image of an example of a multilayer sheet according to the present invention.

Figure 3 is a cross-sectional SEM image of an example of a multilayer sheet according to the present invention.

The present invention to solve the above problems is to melt polyolefin resin on one or both sides of a nonwoven fabric sheet mixed with natural fibers and synthetic fibers with a thickness of 0.5 to 10 mm supplied from a T-die extruder under conditions of 250 to 350 ° C. It relates to a multi-layer sheet in which polyolefin resin films or sheet layers are extruded and laminated.

In addition, in the present invention, the natural fiber may be a multilayer sheet that is a hollow natural fiber or a non-hollow natural fiber.

Additionally, in the present invention, the hollow natural fiber may be a multi-layer sheet of kapok fiber.

In addition, the present invention is a multilayer sheet wherein the non-hollow natural fiber is at least one selected from the group consisting of cotton, cotton, flax, hemp, hemp, jute, sheep hemp, sarago, cyral, maguey, buntal, raffia, and enegen. You can.

Additionally, the present invention may be a multilayer sheet in which the synthetic fiber is at least one selected from the group consisting of polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers.

In addition, the present invention may be a multi-layer sheet in which the synthetic fiber is a core-sheath type composite yarn.

In addition, the present invention provides that the polyolefin resin is at least one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, and polybutene. It may be a multi-layer sheet.

In the present invention, the main component means that the molar ratio of ethylene or propylene is 50% or more, specifically 70% or more, and specifically 90% or more.

Additionally, the present invention may be a multilayer sheet in which a polyolefin resin containing a maleic anhydride group or an epoxy group is further added to the polyolefin resin.

Additionally, the present invention may be a multilayer sheet in which a quaternary ammonium salt or a quaternary phosphonium salt is further added to the polyolefin resin.

Additionally, the present invention may be a multilayer sheet in which polyolefin elastomer is further added to the polyolefin resin.

In addition, the present invention may be a multilayer sheet in which one or more selected from the group consisting of inorganic fillers, lubricants, antioxidants, heat resistant agents, ultraviolet absorbers, antistatic agents, and deodorants are further added to the polyolefin resin.

Additionally, the present invention may be a multilayer sheet in which the inorganic filler is one or more selected from the group consisting of talc, calcium carbonate, silica, kaolin, alumina, wollastonite, sepiolite, zonotolite, titanium dioxide, and glass fiber.

Additionally, the present invention may be a multilayer sheet in which a woven or knitted sheet is further included in the blended nonwoven fabric sheet.

In addition, the present invention may be an eco-friendly automobile interior material obtained by placing the obtained multilayer sheet in a mold of a certain shape and heat compression.

In addition, the present invention may be an eco-friendly automobile interior material obtained by placing the obtained multilayer sheet in a mold of a certain shape, preforming it by heat compression, and rear-injecting polyolefin resin.

In the present invention, a representative example of the hollow natural fiber is kapok fiber. Kapok fiber is a fiber collected from the stellate of a tree that can reach a height of 10 to 15 m. The shape of the actinidia is different from that of cotton, it is 10 to 15 cm long and radial with a maximum diameter of 4 to 6 cm in the central part. When this sty is mature, it opens on its own and fibers grow from within. Cotton itself hangs down when grown, but kapok is harvested before the skeins open because the seeds fly away when the wind blows. The seeds are considerably smaller and redder than cotton seeds, and can be easily separated from the seeds and fibers with just a light tap, so there is no need for cumbersome operations such as cotton ginning. The length of kapok fiber is generally 18 to 27 mm and the diameter is about 0.02 mm. The interior of the fiber is completely hollow, and its specific gravity is extremely low at 0.29, making it very suitable as a lightweight material.

In the present invention, the non-hollow natural fibers include cotton, cotton, flax, hemp, hemp, jute, sheep hemp, sarago, cyral, maguey, buntal, raffia, and enegen, and cotton fiber obtained from cotton. It is easy to obtain, has excellent mechanical properties, and is most appropriate in terms of economic efficiency.

In the present invention, synthetic fibers are synthetic fibers obtained by conventional manufacturing methods using thermoplastic resins, and examples include polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers. Among these, they have excellent mechanical properties and are economical. This excellent polyester fiber is most suitable. There are also the above synthetic fibers made of a single material, but those obtained by combining them, such as composite yarns with a core of polypropylene and a sheath of polyethylene, composite yarns with a core of polyester and a sheath of polyethylene or polypropylene. There may be a deep-sheath type complex. In addition, for weight reduction, which is another object of the present invention, polypropylene fibers with a specific gravity of about 0.90 are preferable, and it is also good to use hollow synthetic fibers such as hollow polyester fiber (product name Airlet) from Toray, Japan.

In the present invention, the polyolefin resin includes low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, polybutene, etc., and polyolefins. It can be produced by a polymerization method using a Ziegler-based catalyst, a chromium-based catalyst, or a metalocene-based catalyst. The copolymer may be in the form of a random copolymer or a block copolymer, and the molecular structure may be atactic, isotactic, or Any of the syndiotactic methods may be used, and the polymerization method may be a low-pressure method, a medium-pressure method, or a high-pressure method. In terms of weight reduction, which is another object of the present invention, polypropylene with a specific gravity of about 0.90 among the polyolefins and copolymers containing propylene as a main component are more preferable.

As previously explained, a representative method of producing carbon-neutral natural fiber-containing automobile interior materials is to mix a compatibilizer such as hydrophilic natural fiber powder, hydrophobic polypropylene resin, and maleic anhydride grafted polyolefin resin using a kneader, single-screw extruder, or twin-screw extruder. The resin composite obtained by compounding as described above was obtained by injection molding. However, according to this method, in order to obtain a high degree of dispersion of natural fiber powder during compounding, natural fibers are easily carbonized due to severe friction between the kneader blade and the cylinder, and between the extruder screw and the cylinder, and high processing heat, resulting in deterioration of mechanical properties and serious odor generation. There was a problem and improvement was urgent.

Another method includes a first step of producing felt from a mixture of natural fibers and synthetic fibers; A method of manufacturing a sheet suitable for automobile interior materials was proposed by a second step of spraying or applying liquid isocyanate to the surface of the felt and hot pressing and curing the felt sprayed with the liquid isocyanate. However, the manufacturing process is complicated and the manufacturing cost increases significantly. There was a serious problem with the generation of odor and VOCs from unreacted liquid isocyanate residue, so this also needed improvement.

Accordingly, in order to obtain a high degree of dispersion of natural fiber powder, the present inventors used a natural fiber sheet layer and a polyolefin resin film or A multilayer sheet laminated with sheet layers was assumed.

However, natural fibers generally have the disadvantage of having weaker mechanical properties compared to synthetic fibers, and in particular, hollow natural fibers have even worse mechanical properties. As a way to solve this problem, nonwoven sheets blended with natural fibers and synthetic fibers were introduced.

In addition, the method of using liquid isocyanate, which has a high risk of generating odor, as in the prior art, or using chemical adhesives such as other acrylic adhesives, urethane adhesives, and epoxy adhesives was excluded, and polyolefin was used to achieve the low manufacturing cost goal through a simple process. An attempt was made to thermally bond a film or sheet layer formed by extrusion of a resin and a nonwoven sheet layer mixed with natural fibers and synthetic fibers.

However, in the case of manufacturing films or sheets of ordinary polyolefin resin, extrusion is carried out at a temperature of 20 to 40 ℃ or higher compared to the melting point of polyolefin resin, and considering that the melting point of polypropylene homopolymer is 165 ℃, the extrusion temperature is up to 205 ℃. In this case, a polyolefin film or sheet layer was formed, but a serious problem occurred in that it quickly peeled off from the nonwoven sheet layer mixed with natural fibers and synthetic fibers. For example, looking at Figure 1, it can be inferred that there is a space that is not thermally bonded, so peeling can easily occur. In other words, it was determined that the phenomenon occurred because the bonding force between the nonwoven fabric layer mixed with hydrophilic natural fibers and synthetic fibers and the hydrophobic polyolefin resin film or sheet layer was extremely weak.

However, polyolefin resin is applied to one or both sides of the non-woven fabric sheet mixed with natural fibers and synthetic fibers supplied from a T-die extruder at temperatures above 250°C and above 260°C. Above 270℃, above 280℃, above 290℃, above 300℃, above 310℃, above 310℃, above 320℃, above 330℃, above 320℃, above 330℃, above 340℃, above 350℃, above 370℃ and temperatures between these values, for example in the range of 250 to 370°C, preferably in the range of 270 to 360°C, more preferably in the range of 290 to 350°C, and even more preferably in the range of 300 to 340°C. As a result of melt extrusion at a temperature significantly higher than the molding temperature of polyolefin, that is, under extremely high specific temperature conditions, the polyolefin resin flows almost like water with an extremely low viscosity and permeates the blended nonwoven fabric sheet, and after cooling, the so-called polyolefin resin physically anchors. ) was formed, and it was found that lamination was possible without peeling due to this strong bonding force. In particular, at 290 ~ 350℃, it is even better because it has better anchoring, no carbonization of fibers or resin, and mechanical properties are significantly increased.

Looking at Figure 2, it can be seen that the polyolefin resin penetrates into the non-woven fabric sheet mixed with non-hollow natural fibers and synthetic fibers and fills all empty spaces, thereby physically anchoring the polyolefin resin and bonding strongly without peeling. In addition, looking at Figure 3, even in the case of a nonwoven fabric sheet mixed with hollow natural fibers and synthetic fibers, the polyolefin resin seeps into various places and fills empty spaces, so that the polyolefin resin is physically anchored and strongly bonded without peeling.

During the heat bonding lamination process by melt extrusion, the melt temperature of the polyolefin resin is extruded at a temperature significantly higher than the processing temperature during normal extrusion, so there is no risk of the formed polyolefin resin film or sheet being peeled due to anchoring, and also the polyolefin resin film or sheet is extruded at a temperature significantly higher than the processing temperature during normal extrusion. The purpose of the present invention can be achieved because there is no risk that the resin will thermally decompose, resulting in loss of thickness uniformity or deterioration of mechanical properties.

In the end, the thermal bonding process by melt extrusion at a specific high temperature between the non-woven sheet layer of the blended natural fiber and synthetic fiber as described above and the polyolefin resin film or sheet layer provides excellent mechanical properties and deodorization without generating odor. The present invention was completed after seeing that a multi-layer sheet suitable for automobile interior materials was obtained, which is excellent and has a simple manufacturing process, so the manufacturing cost is very low, and is eco-friendly due to the natural fiber, a carbon-neutral material contained.

In the case of the multilayer sheet according to the present invention, the thickness of the nonwoven sheet blended with natural fibers and synthetic fibers is not limited as long as it achieves the purpose of the present invention, but for example, it is preferably 0.5 to 10 mm, and more preferably 0.7 to 7 mm. Preferably, the polyolefin resin film or sheet layer is preferably 0.1 to 3 mm thick, and more preferably 0.3 to 2 mm thick.

The thickness of the polyolefin resin film or sheet layer is a thickness measured from the surface of the nonwoven fabric, not the impregnated portion of the nonwoven fabric.

Sufficient target physical properties can be obtained by bonding between a nonwoven fabric sheet layer mixed with natural fibers and synthetic fibers and a polyolefin film or sheet layer by physical anchoring as described above, but a method of further strengthening the bonding force is to add a hydrophilic functional group to the polyolefin resin. It is good to add a small amount of polyolefin resin containing maleic anhydride or epoxy group. This is because the hydroxyl group contained in cellulose, the main component of natural fiber, and the maleic anhydride group or epoxy group react to form a covalent bond, thereby imparting strong affinity.

Specific examples of the maleic anhydride group-containing polyolefin resin include maleic anhydride group-grafted low-density polyethylene (DuPont's Fusabond MB2260D), maleic anhydride group-grafted linear low-density polyethylene (DuPont's Fusabond MB528D, Mitsui's Admer GT6E), and maleic anhydride group-grafted high-density polyethylene. Polyethylene (Fusabond MB100D, DuPont), maleic anhydride grafted ethylene-vinylacetate copolymer (Fusabond MC190D, DuPont), grafted ethylene-propylene rubber (Fusabond, DuPont, Fusabond MF416D), grafted polypropylene (Fusabond, DuPont) DuPont Fusabond MD41D, Mitsui Admer QF460E), etc.

In addition, specific examples of the epoxy group-containing polyolefin include Igetabond 2C (GMA content 6% by weight, manufactured by Sumitomo Chemical), Lotader AX8840 (GMA content 8% by weight, manufactured by Arkema), Igetabond E (GMA content 12% by weight, manufactured by Sumitomo Chemical), etc. Ethylene-glycidyl methacrylate copolymer, ethylene-butylacrylate-glycidyl methacrylate copolymer such as Elvaloy PTW (GMA content 5% by weight, DuPont), Lotader AX8900 (GMA content 8% by weight, Arkema) and ethylene-methyl acrylate-glycidyl methacrylate copolymers such as those manufactured by the company.

The appropriate amount of the polyolefin resin containing maleic anhydride or epoxy group is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polyolefin resin.

As a further improvement, it would be better to additionally add a quaternary ammonium salt or a quaternary phosphonium salt to the polyolefin resin along with a polyolefin containing a maleic anhydride group or an epoxy group, which is a hydrophilic functional group. This is because the hydroxyl group contained in cellulose, the main component of natural fiber, reacts with the maleic anhydride group or epoxy group to form a covalent bond, thereby acting as a kind of catalyst and giving stronger affinity.

Specific examples of the quaternary ammonium salt include tetramethyl ammonium bromide, tetraethyl ammonium bromide, tetrapropyl ammonium bromide, tetrabutyl ammonium bromide, tetrapentyl ammonium bromide, tetrahexyl ammonium bromide, and tetramethyl ammonium chloride. , tetraethyl ammonium chloride, tetrapropyl ammonium chloride, tetrabutyl ammonium chloride, tetrabutyl ammonium iodide, tetrabutyl ammonium hydrogen sulfate, tetrabutyl ammonium perchlorate, benzyltrimethyl ammonium chloride, benzyltriethyl ammonia. um chloride, etc., and specific examples of the quaternary phosphonium salt include tetrabutyl phosphonium bromide, ethyltriphenyl phosphonium bromide, methyltributyl phosphonium chloride, and benzyltriphenyl chloride. .

The appropriate amount of the quaternary ammonium salt or quaternary phosphonium salt added is 0.0001 to 0.1 parts by weight, preferably 0.001 to 0.05 parts by weight, based on 100 parts by weight of the polyolefin resin.

Additionally, to improve the impact resistance of the multilayer sheet, additional polyolefin elastomer can be added to the polyolefin resin.

In addition, without departing from the purpose of the present invention, inorganic fillers and lubricants such as conventional talc, calcium carbonate, silica, kaolin, alumina, wollastonite, sepiolite, zonotolite, titanium dioxide, and glass fiber can be added to the polyolefin resin. , antioxidants, heat resistant agents, ultraviolet absorbers, antistatic agents, etc. can be added.

In addition, the present invention may be a multi-layer sheet in which a woven or knitted sheet is further included in the non-woven fabric sheet blended with natural fibers and synthetic fibers. The woven or knitted sheet may be made of only natural fibers or synthetic fibers, or may be a blend of natural fibers and synthetic fibers.

In addition, the present invention may be an eco-friendly automobile interior material obtained by placing the obtained multilayer sheet in a mold of a certain shape and heat compression.

In addition, the present invention may be an eco-friendly automobile interior material obtained by placing the obtained multilayer sheet in a mold of a certain shape, preforming it by heat compression, and rear-injecting polyolefin resin.

The multilayer sheet obtained in this way, in which a polyolefin resin film or sheet layer is combined and laminated to a nonwoven fabric sheet mixed with natural fibers and synthetic fibers according to the present invention, has excellent mechanical properties and low odor while being eco-friendly due to the natural fiber contained in it, which is a carbon-neutral material. It is suitable for automobile interior materials such as instrument panels, door trims, interior trims, ceiling materials, and car seats.

In addition, when hollow natural fibers are used among the natural fibers, they are suitable for lightweight automobile interior materials that have excellent lightness, excellent mechanical properties, low odor, and eco-friendliness.

A method for manufacturing the multilayer sheet of the present invention is described.

The present invention provides a blended nonwoven fabric sheet blended with natural fibers and synthetic fibers; And applying molten polyolefin resin to one or both sides of the blended nonwoven fabric sheet and extruding it with a T-die extruder. A method of manufacturing a multilayer sheet in which polyolefin resin film or sheet layers are bonded and laminated, comprising: The natural fiber has a thickness of 0.5 to 10 mm, and the melting temperature of the polyolefin resin melted in the T-die extruder is 250 to 350°C. A method for manufacturing a multilayer sheet can be provided.

A multilayer sheet with a multilayer structure can be manufactured by applying molten polyolefin resin to one or both sides of the blended nonwoven sheet and pressing it with a T-die extruder. According to one aspect of the present invention, the melting temperature of the polyolefin resin melted in the T-die extruder may be 290 to 340° C., and specifically, the melting temperature of the polyolefin resin melted in the T-die extruder may be 300 to 330° C. It may be ℃, but is not limited thereto.

The natural fiber may be a hollow natural fiber or a non-hollow natural fiber, but since this has been described in detail previously, it is omitted here.

The synthetic fiber may be one or more selected from the group consisting of polyolefin fiber, polyester fiber, polyamide fiber, and polyurethane fiber, but this has been described in detail previously and is omitted here. The polyolefin resin may be one or more selected from the group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, and polybutene. This has been explained in detail previously, so it is omitted here.

One or more selected from the group consisting of inorganic fillers, lubricants, antioxidants, heat resistant agents, ultraviolet absorbers, antistatic agents, and deodorants may be further added to the polyolefin resin, but this has been described in detail previously and is omitted here.

The present invention will be described in more detail through examples below. The following example is only an example and is not limited to the example.

Natural fiber content was evaluated as a measure of eco-friendliness of the multilayer sheet manufactured according to the following examples and comparative examples, density was evaluated as a measure of weight reduction, flexural strength and flexural modulus were evaluated as a measure of mechanical properties, and deodorization was evaluated as a measure. The odors used in the evaluation of automobile interior materials were evaluated as follows.

(Natural fiber content)

Natural fiber content was evaluated according to ASTM D6866.

(density)

As a measure of weight reduction, the density of composite sheet samples was measured according to ASTM D792.

(Bending strength)

The flexural strength (MPa) of the sample was evaluated in accordance with KS M ISO 178.

(flexural modulus)

The flexural modulus (MPa) of the sample was evaluated according to KS M ISO 178.

(smell)

The odor of the sample was evaluated according to MS361-15. Normally, if it is level 3 or lower, it is judged as passing.

[Example 1]

A nonwoven fabric (nonwoven fabric A) sheet with a thickness of 4.5 mm and a 60/40 ratio of cotton A, a non-hollow natural fiber, and polyester fiber A, a synthetic fiber, was prepared. Polypropylene (Lotte Chemical L270A, PP A) with a melt index (230°C, 2.16Kg) of 26.0g/10min and a density of 0.90g/ ^cm3 was prepared as a polyolefin resin. PP A was melt-extruded on one side of the non-woven fabric A sheet supplied from a 90Φ T-die extruder under conditions of 305°C to prepare a multi-layer sheet in which polyolefin resin sheet layers with a thickness of 0.5 mm were bonded and laminated. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Example 2]

A non-woven fabric (non-woven fabric B) sheet with a thickness of 4.1 mm and an 80/20 ratio of cotton A, a non-hollow natural fiber, and polyester fiber A, a synthetic fiber, was prepared. PP A is melt-extruded on both sides of the non-woven fabric B sheet supplied from a 90Φ T-die extruder under conditions of 310°C to produce a multi-layer sheet in which polyolefin resin sheet layers with a thickness of 0.3 mm on one side and a total thickness of 0.6 mm are combined and laminated. did. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Example 3]

A 3.2 mm thick non-woven non-woven fabric (non-woven fabric C) sheet was prepared with a 75/25 ratio of cotton A, a non-hollow natural fiber, and polyester fiber A, a synthetic fiber. Maleic anhydride group grafted polypropylene (DuPont, Fusabond MD41D, MAH-g-PP) was prepared as a maleic anhydride group grafted polyolefin. On one side of the nonwoven C sheet supplied from a 90Φ T-die extruder, a composition of 99.5% by weight of PP A and 0.5% by weight of MAH-g-PP is melt-extruded under conditions of 300°C to form a polyolefin sheet layer with a thickness of 0.3 mm. A laminated multilayer sheet was manufactured. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Example 4]

A nonwoven fabric (nonwoven fabric D) sheet with a thickness of 6.4 mm and a 90/10 ratio of cotton A, a non-hollow natural fiber, and polyester fiber A, a synthetic fiber, was prepared. Tetramethylammonium bromide (Aldrich Chemical, TMAB) was prepared as a quaternary ammonium salt. 99.499% by weight of PP A and 0.5% by weight of MAH-g-PP were added to both sides of the nonwoven D sheet supplied from a 90Φ T-die extruder. , a composition containing 0.001% by weight of TMAB was melt-extruded under conditions of 300°C to prepare a multilayer sheet in which polyolefin resin sheet layers with a thickness of 0.6 mm on one side and a total thickness of 1.2 mm were laminated. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Example 5]

As a hollow natural fiber, KAPOK A was prepared from Java, Indonesia, with an average fiber length of about 22 mm and a diameter of about 0.02 mm. A 3.8 mm thick blended nonwoven fabric (nonwoven fabric E) sheet with a 70/30 ratio of KAPOK A, a hollow natural fiber, and polyester fiber A, a synthetic fiber, was prepared. PP A is melt-extruded on both sides of the non-woven E sheet supplied from a 90Φ T-die extruder under conditions of 315°C to produce a multi-layer sheet in which polyolefin resin sheet layers with a thickness of 0.75 mm on one side and a total thickness of 1.5 mm are combined and laminated. did. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Example 6]

A 3.2 mm thick blended nonwoven fabric (nonwoven fabric F) sheet with a 75/25 ratio of KAPOK A, a hollow natural fiber, and polyester fiber A, a synthetic fiber, was prepared. A composition of 98.25% by weight of PP A, 1.0% by weight of MAH-g-PP, and 0.002% by weight of TMAB is melt-extruded on both sides of the nonwoven F sheet supplied from a 90Φ T-die extruder under conditions of 320°C to have a thickness of 0.4 on one side. A multilayer sheet in which polyolefin resin sheet layers with a total thickness of 0.8 mm and a total thickness of 0.8 mm were combined and laminated was manufactured. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Comparative Example 1]

Bamboo short fibers (midou, bamboo fiber A) with a length of 6 to 7 mm and a thickness of 0.6 to 0.7 mm were prepared. A composition of 68% by weight of PP A, 30% by weight of bamboo fiber A, and 2% by weight of MAH-g-PP was compounded using a twin-screw extruder to prepare a polypropylene composite containing 30% by weight of natural fiber, which was then injection molded to form a sheet. Phase samples were obtained. The physical properties of the obtained sheet-like sample were evaluated and are shown in Table 1.

[Comparative Example 2]

A multilayer sheet was manufactured in the same manner as in Example 2, except that the extrusion temperature was set to 195°C. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Comparative Example 3]

A multilayer sheet was manufactured in the same manner as in Example 2, except that the extrusion temperature was set to 230°C. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

[Comparative Example 4]

A multilayer sheet was manufactured in the same manner as in Example 5, except that the extrusion temperature was set to 240°C. The physical properties of the obtained multilayer sheet samples were evaluated and are shown in Table 1.

Looking at Examples 1 to 6, it can be seen that the mechanical properties are more excellent when the maleic anhydride group-containing polyolefin resin or the maleic anhydride group-containing polyolefin resin and the quaternary ammonium salt as a catalyst are additionally used together, but the natural fiber-containing polyolefin resin composition is 2. Compared to Comparative Examples 1 and 2 according to the prior art, which were compounded using a shaft extruder, it can be seen that the Example according to the present invention has excellent mechanical properties, excellent deodorization, and a very high natural fiber content. In particular, it can be seen that even when hollow natural fibers are used as in Examples 5 and 6, mechanical properties are excellent and at the same time, a significant weight reduction is achieved.

Additionally, when comparing Example 2 with Comparative Examples 2 to 3 and Example 5 with Comparative Example 4, it can be seen that the physical properties of the multilayer film vary significantly depending on the extrusion temperature of the polyolefin resin. That is, in the case of the sample of Comparative Example 2 laminated at a relatively low extrusion temperature, there is a major problem of peeling, but in the case of the sample of Example 2 laminated at a high extrusion temperature, it can be seen that the mechanical properties are excellent without peeling due to the physical anchoring phenomenon. there is.

Claims (23)

Polyolefin resin is melt-extruded under conditions of 250 to 350°C on one or both sides of a nonwoven fabric sheet mixed with natural fibers and synthetic fibers with a thickness of 0.5 to 10 mm supplied from a T-die extruder to form a polyolefin resin film or sheet layer. Combined laminated multi-layer sheets. According to clause 1, The natural fiber is a multilayer sheet that is hollow natural fiber or non-hollow natural fiber. According to clause 2, The hollow natural fiber is a multilayer sheet of kapok fiber. In paragraph 2 A multilayer sheet wherein the non-hollow natural fiber is at least one selected from the group consisting of cotton, cotton, flax, hemp, hemp, jute, sheep hemp, sarago, cyral, maguey, buntal, raffia, and enegen. In paragraph 1 A multilayer sheet wherein the synthetic fiber is at least one selected from the group consisting of polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers. According to clause 1, A multilayer sheet in which the synthetic fiber is a core-sheath type composite material. According to clause 1, The polyolefin resin is at least one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, and polybutene. A multilayer sheet. In paragraph 1 A multilayer sheet in which a polyolefin resin containing a maleic anhydride group or an epoxy group is further added to the polyolefin resin. According to clause 1, A multilayer sheet in which a quaternary ammonium salt or a quaternary phosphonium salt is further added to the polyolefin resin. In paragraph 1 A multilayer sheet in which polyolefin elastomer is further added to the polyolefin resin. In paragraph 1 A multilayer sheet in which at least one selected from the group consisting of inorganic fillers, lubricants, antioxidants, heat resistant agents, ultraviolet absorbers, antistatic agents, and deodorants is further added to the polyolefin resin. In clause 11 A multilayer sheet wherein the inorganic filler is at least one selected from the group consisting of talc, calcium carbonate, silica, kaolin, alumina, wollastonite, sepiolite, zonotolite, titanium dioxide, and glass fiber. In paragraph 1 A multilayer sheet further comprising a woven or knitted sheet in the blended nonwoven sheet. In paragraph 1 A multilayer sheet, wherein the polyolefin resin film or sheet layer has a thickness of 0.1 to 3 mm. An eco-friendly automobile interior material obtained by placing the multilayer sheet of any one of claims 1 to 14 in a mold of a certain shape and heat compression. An eco-friendly automobile interior material obtained by placing the multilayer sheet of any one of claims 1 to 14 in a mold of a certain shape, preforming it by heat compression, and rear-injecting polyolefin resin. Blended nonwoven fabric sheet made by blending natural fibers and synthetic fibers; and A method of manufacturing a multilayer sheet in which polyolefin resin films or sheet layers are bonded and laminated, including the step of applying molten polyolefin resin to one or both sides of the blended nonwoven fabric sheet and extruding it with a T-die extruder, The natural fiber has a thickness of 0.5 to 10 mm, and the melting temperature of the polyolefin resin melted in the T-die extruder is 250 to 350 ° C. According to claim 17, A method of manufacturing a multilayer sheet, wherein the extrusion temperature of the T-die extruder is 290 ~ 340 ℃. According to claim 17, A method of manufacturing a multilayer sheet, wherein the extrusion temperature of the T-die extruder is 300 ~ 330 ℃. According to clause 17, A method of manufacturing a multi-layer sheet, wherein the natural fiber is a hollow natural fiber or a non-hollow natural fiber. In clause 17 A method of manufacturing a multilayer sheet, wherein the synthetic fiber is at least one selected from the group consisting of polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers. According to clause 17, The polyolefin resin is one or more selected from the group consisting of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, copolymers based on ethylene, polypropylene, copolymers based on propylene, and polybutene. Manufacturing method. In clause 17 A method of manufacturing a multi-layer sheet, wherein at least one selected from the group consisting of an inorganic filler, lubricant, antioxidant, heat resistant agent, ultraviolet absorber, antistatic agent, and deodorant is further added to the polyolefin resin.

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