Patent Publication Number: US-2022227982-A1

Title: Polyolefin-based resin composition for vehicle interior material comprising spent coffee grounds

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority based on Korean Patent Application No. 10-2021-0007805, filed on Jan. 20, 2021, the entire content of which is incorporated herein for all purposes by this reference. 
     TECHNICAL FIELD 
     The present invention relates to a polyolefin-based resin composition for a vehicle interior material including waste coffee grounds. 
     BACKGROUND 
     With the recent increase in environment-friendly vehicles such as electric vehicles, etc., the need to develop parts using environment-friendly materials is increasing. Moreover, there is a consumer tendency to consider the influence of the vehicle on the environment as a factor in making a vehicle purchase. 
     Meanwhile, coffee is a popular beverage enjoyed by people of all ages and genders, and the coffee-related market has been explosively growing year over year due to the emergence of various coffee makers and the explosive increase in the number of coffee shops. 
     Coffee consumption in Korea is very high, specifically 333 cups per person per year, and in connection therewith, 300,000 tons of waste coffee grounds, coffee husks, and the like are discarded per year. Some waste coffee grounds are used as deodorant or the like, but this is only for personal consumption, for example, as deodorant or the like, however, the scale thereof is insignificant. 
     To date, most waste coffee grounds generated in Korea are sent to the landfill or incinerated. However, it is not known how waste coffee grounds discarded in landfills will affect the soil and organisms due to the caffeine, tannins and other components of coffee, and moreover, incineration generates combustion gases and causes air pollution. 
     Therefore, research for methods of recycling waste coffee grounds to reduce waste generation in an industrially useful and effective manner has been conducted. 
     For example, attempts have been being made to develop fibers or resins having waste coffee grounds added thereto. However, because waste coffee grounds are a natural material having a hydrophilic molecular structure, the water content thereof is high, so during processing thereof, undried water therein causes generation of gases, emission of VOCs, and a poor appearance. 
     Waste coffee grounds contain water and low-molecular-weight materials such as cellulose, hemicellulose and the like in large amounts, and in order to remove water and low-molecular-weight materials, washing with an organic solvent such as an alcohol, etc. is performed, but there are disadvantages in that the removal efficiency is not good and in that harmful chemical materials are used. 
     Specifically, the conventional technology for using waste coffee grounds has not solved problems such as deterioration of properties, emission of odors and VOCs, and the like, and thus limitations are imposed on application thereof to vehicle interior materials. For example, a portion of the waste coffee grounds is carbonized by heat during processing and remains in devices, thus acting as a foreign substance and causing a poor appearance of the molded product. 
     SUMMARY 
     In preferred aspects, provided is a resin composition in which the use of synthetic resin, which is derived from fossil fuels, is reduced by recycling waste coffee grounds. 
     The objectives of the present invention are not limited to the foregoing, and will be able to be clearly understood through the following description and to be realized by the means described in the claims and combinations thereof. 
     In an aspect, provided is a resin composition for a vehicle interior material that may include: a polyolefin-based resin; waste coffee grounds including a water in an amount less than about 2 wt % of the waste coffee grounds; a modified polypropylene; an inorganic filler; a thermoplastic elastomer; and a lubricant. 
     The polyolefin-based resin may include one or more selected from the group consisting of polypropylene, polyethylene, polybutene, polyoctene, polyisoprene, and a copolymer obtained by polymerizing at least one monomer selected from the group consisting of propylene, ethylene, butylene and octene. 
     The polyolefin-based resin may suitably include a first polypropylene having a melt index (230° C., under a load of 2.16 kg) of about 10 g/10 minutes to 30 g/10 minutes and a second polypropylene having a melt index (230° C., under a load of 2.16 kg) of about 50 g/10 minutes to 100 g/10 minutes. 
     The polyolefin-based resin may suitably include the first polypropylene and the second polypropylene at a weight ratio of about 8:2 to 9:1. 
     The waste coffee grounds may have an average particle diameter (D50) of about 500 μm to 1,000 μm. 
     The modified polypropylene may include one or more selected from the group consisting of a polypropylene homopolymer, a propylene/α-olefin copolymer, and a propylene/non-conjugated diene-based compound copolymer, which may be modified with a functional group. 
     The functional group may suitably include at least one selected from the group consisting of maleic anhydride, carboxylic acid, carboxylic anhydride, epoxy, hydroxyl, amino, isocyanate, thiol, and oxazoline. 
     The modified polypropylene may suitably include about 5 wt % to 10 wt % of the functional group based on the weight of the polypropylene. 
     The inorganic filler may include one or more selected from the group consisting of talc, calcium carbonate, and barium sulfate. 
     The thermoplastic elastomer may include one or more selected from the group consisting of ethylene-α-olefin copolymer rubber, and styrene-olefin-based rubber. 
     The ethylene-α-olefin copolymer rubber may include one or more selected from the group consisting of ethylene propylene copolymer, ethylene butene-1 copolymer, and ethylene octene-1 copolymer. 
     The styrene-olefin-based rubber may include one or more selected from the group consisting of styrene-ethylene-butylene-styrene rubber, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, and styrene-butadiene rubber. 
     The lubricant may include a fatty-acid-amide-based lubricant. 
     The resin composition may suitably include an amount of about 50 wt % to 70 wt % of the polyolefin-based resin, an amount of about 5 to 20 wt % of the waste coffee grounds, an amount of about 1 wt % to 5 wt % of the modified polypropylene, an amount of about 10 wt % to 20 wt % of the inorganic filler, an amount of about 10 wt % to 20 wt % of the thermoplastic elastomer, and an amount of about 0.1 wt % to 3 wt % of the lubricant, based on the total weight of the resin composition. 
     According to various exemplary embodiments of the present invention, it is possible to obtain a resin composition in which the use of a synthetic resin derived from fossil fuel is reduced by recycling waste coffee grounds. 
     According to various exemplary embodiments of the present invention, when processing waste coffee grounds using a lubricant, it is possible to reduce a degradation phenomenon, thereby reducing the emission of odors and VOCs. 
     According to various exemplary embodiments of the present invention, by improving the release performance of waste coffee grounds, it is possible to decrease the shear stress in the extruder and reduce the occurrence of foreign substances due to carbonization of the waste coffee grounds. 
     According to various exemplary embodiments of the present invention, a vehicle interior material having a unique appearance can be obtained using the unique pattern of waste coffee grounds that appears during injection. 
     The effects of the present invention are not limited to the foregoing, and should be understood to include all effects that can be reasonably anticipated from the following description. 
     Other aspects of the invention are disclosed infra. 
    
    
     DETAILED DESCRIPTION 
     The above and other objectives, features and advantages of the present invention will be more clearly understood from the following preferred embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed herein, and may be modified into different forms. These embodiments are provided to thoroughly explain the invention and to sufficiently transfer the spirit of the present invention to those skilled in the art. 
     Throughout the drawings, the same reference numerals will refer to the same or like elements. For the sake of clarity of the present invention, the dimensions of structures are depicted as being larger than the actual sizes thereof. It will be understood that, although terms such as “first”, “second”, etc. may be used herein to describe various elements, these elements are not to be limited by these terms. These terms are only used to distinguish one element from another element. For instance, a “first” element discussed below could be termed a “second” element without departing from the scope of the present invention. Similarly, the “second” element could also be termed a “first” element. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     It will be further understood that the terms “comprise”, “include”, “have”, etc., when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. Also, it will be understood that when an element such as a layer, film, area, or sheet is referred to as being “on” another element, it can be directly on the other element, or intervening elements may be present therebetween. Similarly, when an element such as a layer, film, area, or sheet is referred to as being “under” another element, it can be directly under the other element, or intervening elements may be present therebetween. 
     Unless otherwise specified, all numbers, values, and/or representations that express the amounts of components, reaction conditions, polymer compositions, and mixtures used herein are to be taken as approximations including various uncertainties affecting measurement that inherently occur in obtaining these values, among others, and thus should be understood to be modified by the term “about” in all cases. 
     Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from the context, all numerical values provided herein are modified by the term “about.” 
     Furthermore, when a numerical range is disclosed in this specification, the range is continuous, and includes all values from the minimum value of said range to the maximum value thereof, unless otherwise indicated. Moreover, when such a range pertains to integer values, all integers including the minimum value to the maximum value are included, unless otherwise indicated. 
     In the present specification, when a range is described for a variable, it will be understood that the variable includes all values including the end points described within the stated range. For example, the range of “5 to 10” will be understood to include any subranges, such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, and the like, as well as individual values of 5, 6, 7, 8, 9 and 10, and will also be understood to include any value between valid integers within the stated range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, 6.5 to 9, and the like. Also, for example, the range of “10% to 30%” will be understood to include subranges, such as 10% to 15%, 12% to 18%, 20% to 30%, etc., as well as all integers including values of 10%, 11%, 12%, 13% and the like up to 30%, and will also be understood to include any value between valid integers within the stated range, such as 10.5%, 15.5%, 25.5%, and the like. 
     The present invention pertains to a polyolefin-based resin composition for a vehicle interior material that may include a polyolefin-based resin, waste coffee grounds, modified polypropylene, an inorganic filler, a thermoplastic elastomer, and a lubricant. 
     Hereinafter, individual components of the resin composition are described in detail. 
     (A) Polyolefin-Based Resin 
     The polyolefin-based resin may be a base resin, and may include a thermoplastic resin. Preferably, the polyolefin-based resin may include one or more selected from the group consisting of polypropylene, polyethylene, polybutene, polyoctene, polyisoprene, and a copolymer obtained by polymerizing at least one monomer selected from the group consisting of propylene, ethylene, butylene and octene. 
     The polyolefin-based resin may suitably include a first polypropylene having a melt index (230° C., under a load of 2.16 kg) of about 10 g/10 minutes to 30 g/10 minutes and a second polypropylene having a melt index (230° C., under a load of 2.16 kg) of about 50 g/10 minutes to 100 g/10 minutes. 
     When the melt index of the first polypropylene is less than about 10 g/10 minutes, the tensile strength of the molded product may decrease, whereas when the melt index thereof is greater than about 30 g/10 minutes, the impact strength of the molded product may decrease. 
     When the melt index of the second polypropylene is less than about 50 g/10 minutes, the flowability of the resin composition may be reduced, whereas if the melt index thereof is greater than about 100 g/10 minutes, the properties of the molded product may be deteriorated. 
     The polyolefin-based resin may suitably include the first polypropylene and the second polypropylene at a weight ratio of about 8:2 to 9:1. 
     (B) Waste Coffee Grounds 
     In general, waste coffee grounds remaining after coffee extraction may include a water in an amount greater than 50 wt %. When waste coffee grounds having excessive water content are mixed with a resin, gases such as VOCs and the like may be generated due to the water, and the appearance of the molded product may become poor. 
     The waste coffee grounds are dried at a temperature of about 50° C. to 70° C. for 5 hours to about 12 hours using a batch drier such that the water content thereof is lowered to less than 2 wt % and are then used. When the water content of the waste coffee grounds is about 2 wt % or greater of the waste coffee grounds, gases may be excessively generated during processing of molded products and thus pores may be formed therein, which deteriorates the properties thereof. 
     The average particle diameter (D50) of the waste coffee grounds may be about 500 μm to 1,000 μm. The dried waste coffee grounds may be pulverized in order to adjust the average particle diameter (D50) of the waste coffee grounds. When the average particle diameter (D50) of the waste coffee grounds is less than about μm, there may be a problem of poor feeding, whereas when the average particle diameter thereof is greater than about 1,000 μm, dispersibility in the resin composition may be decreased and the properties of the molded product may be deteriorated. 
     (C) Modified Polypropylene 
     The modified polypropylene may include those obtained by modifying one or more polypropylene selected from the group consisting of a polypropylene homopolymer, a propylene/α-olefin copolymer, a propylene/non-conjugated diene-based compound copolymer with a functional group. The functional group may include one or more selected from the group consisting of maleic anhydride, carboxylic acid, carboxylic anhydride, epoxy, hydroxyl, amino, isocyanate, thiol, and oxazoline. 
     Preferably, the modified polypropylene may include polypropylene grafted with maleic anhydride. 
     The modified polypropylene may suitably include an amount of about 5 wt % to 10 wt % of the functional group based on the weight of a resin component such as polypropylene. When the amount of the functional group is less than about 5 wt %, compatibility may decrease, whereas when the amount of the functional group is greater than about 10 wt %, the water content may increase, so odors may be generated during processing of the molded product. 
     (D) Inorganic Filler 
     The inorganic filler may improve the rigidity, impact strength and the like of a molded product. 
     The inorganic filler may include one or more selected from the group consisting of talc, calcium carbonate, and barium sulfate. 
     (E) Thermoplastic Elastomer 
     The thermoplastic elastomer may improve the impact strength, rigidity and the like of a molded product. 
     The thermoplastic elastomer may include one or more selected from the group consisting of ethylene-α-olefin copolymer rubber, styrene-olefin-based rubber, and combinations thereof. 
     The ethylene-α-olefin copolymer rubber may include one or more selected from the group consisting of ethylene propylene copolymer, ethylene butene-1 copolymer, and ethylene octene-1 copolymer. 
     The styrene-olefin-based rubber may include one or more selected from the group consisting of styrene-ethylene-butylene-styrene rubber, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, and styrene-butadiene rubber. 
     (F) Lubricant 
     The lubricant is used to reduce the degradation of waste coffee grounds upon processing of a molded product. The lubricant may include a fatty-acid-amide-based lubricant. 
     The resin composition may suitably include an amount of about 50 to 70 wt % of the polyolefin-based resin, an amount of about 5 wt % to 20 wt % of the waste coffee grounds, an amount of about 1 wt % to 5 wt % of the modified polypropylene, an amount of about 10 wt % to 20 wt % of the inorganic filler, an amount of about 10 wt % to 20 wt % of the thermoplastic elastomer, and an amount of about 0.1 to 3 wt % of the lubricant, based on the total weight of the resin composition. 
     When the amount of the waste coffee grounds is less than about 5 wt %, the effect of reducing the use of synthetic resin due to the addition thereof may become insignificant. On the other hand, when the amount of the waste coffee grounds is greater than about 20 wt %, odors may occur upon processing of the molded product and pores may be formed in the molded product due to the generation of excessive gases upon injection, undesirably deteriorating the properties thereof. 
     When the amount of the modified polypropylene is less than about 1 wt %, the interfacial affinity between the hydrophilic waste coffee grounds and the hydrophobic resin may decrease, and thus the properties of the molded product may deteriorate. On the other hand, when the amount of the modified polypropylene is greater than about 5 wt %, the properties of the molded product may deteriorate and odors may occur. 
     When the amount of the inorganic filler is less than about 10 wt %, the rigidity and heat resistance of the molded product may decrease, whereas when the amount thereof is greater than about 20 wt %, the impact strength of the molded product may decrease. 
     When the amount of the thermoplastic elastomer is less than about 10 wt %, the impact strength of the molded product may decrease, whereas if the amount thereof is greater than about 20 wt %, the rigidity of the molded product may decrease. 
     When the amount of the lubricant is less than about 0.1 wt %, internal shear stress may increase and odors may occur, whereas if the amount thereof is greater than about 3 wt %, the properties of the molded product may deteriorate. 
     EXAMPLE 
     A better understanding of the present invention may be obtained through the following examples and comparative examples. However, these examples are merely set forth to illustrate the present invention, and are not to be construed as limiting the scope of the present invention. 
     Examples 1 and 2 and Comparative Examples 1 to 4 
     Each polyolefin-based resin composition was prepared using components in the amounts shown in Table 1 below. Molded products were manufactured therefrom, and the properties thereof were evaluated. The results thereof are shown in Table 2 below. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Composition [wt %] 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Classification 
                 A-1 
                 A-2 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 Total 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Example 1 
                 55 
                 6.5 
                 5 
                 3 
                 22 
                 8 
                 0.5 
                 — 
                 100 
               
               
                 Example 2 
                 45 
                 6.5 
                 15  
                 3 
                 22 
                 8 
                 0.5 
                 — 
                 100 
               
               
                 Comparative Example 1 
                 60 
                 10 
                 — 
                 — 
                 22 
                 8 
                 — 
                 — 
                 100 
               
               
                 Comparative Example 2 
                 55 
                 7 
                 5 
                 3 
                 22 
                 8 
                 — 
                 — 
                 100 
               
               
                 Comparative Example 3 
                 57 
                 — 
                 — 
                 3 
                 22 
                 8 
                 — 
                 10 
                 100 
               
               
                 Comparative Example 4 
                 58 
                 6.5 
                 5 
                 — 
                 22 
                 8 
                 0.5 
                 — 
                 100 
               
               
                   
               
            
           
         
       
     
     In Table 1, A-1 is a first polypropylene, which is a polypropylene copolymer resin having a melt index (230° C., under a load of 2.16 kg) of 27 g/10 minutes (made by GS Caltex, M560). 
     A-2 is a second polypropylene, which is a polypropylene copolymer resin having a melt index (230° C., under a load of 2.16 kg) of 60 g/10 minutes (made by PolyMirae, EA5075). 
     B is waste coffee grounds having an average particle diameter (D50) of 500 μm to 1,000 μm and a water content of less than 2 wt % (made by 4EN). 
     C is a modified polypropylene grafted with 5 wt % of maleic anhydride (made by Iruchem, Irubond100). 
     D is an inorganic filler, that is, talc having an average particle size of 4.5 μm (made by KOCH). 
     E is a thermoplastic elastomer, that is, an octene-based polyolefin impact modifier having a melt index (190° C., under a load of 2.16 kg) of 13 g/10 minutes (made by Dow, Engage8137). 
     F is a lubricant, particularly a fatty-acid-amide-based lubricant in which fatty acid soap and amide are mixed (made by Iruchem, TPX1000). 
     G is bamboo wood powder (made by Jeru Plastics). 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                   
                 Izod 
                 Heat 
                   
               
               
                   
                 Tensile 
                 Bending 
                 Bending 
                 impact 
                 deformation 
               
               
                   
                 strength 
                 strength 
                 modulus 
                 strength 
                 temperature 
                 Odor 
               
               
                 Classification 
                 [MPa] 
                 [MPa] 
                 [MPa] 
                 [KJ/m 2 ] 
                 [° C.] 
                 [ranking] 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Example 1 
                 22 
                 35 
                 2230 
                 4.9 
                 112 
                 2.5 
               
               
                 Example 2 
                 21 
                 33 
                 2280 
                 4.8 
                 111 
                 2.5 
               
               
                 Comparative 
                 24 
                 37 
                 2400 
                 5.4 
                 116 
                 1.5 
               
               
                 Example 1 
               
               
                 Comparative 
                 21 
                 35 
                 2150 
                 3.9 
                 112 
                 3.5 
               
               
                 Example 2 
               
               
                 Comparative 
                 19 
                 36 
                 2410 
                 3.2 
                 113 
                 3.5 
               
               
                 Example 3 
               
               
                 Comparative 
                 19 
                 33 
                 2200 
                 3.9 
                 110 
                 2.5 
               
               
                 Example 4 
               
               
                   
               
            
           
         
       
     
     In Table 2, the tensile strength, bending strength, bending modulus, Izod impact strength, and thermal deformation temperature were measured according to the following ISO test methods, and odors were evaluated according to MS300-34.
         Tensile strength: ISO 527, a test speed of 50 mm/min   Bending strength: ISO 178, a test speed of 2 mm/min   Bending modulus: ISO 178, a test speed of 2 mm/min   IZOD impact strength: ISO 180, using a notched test piece, room temperature (23° C.)   Heat deformation temperature: ISO 75, a stress of 0.45 MPa       

     As shown in Table 2, Comparative Example 1 was a resin composition not including waste coffee grounds and including polyolefin-based resins (A-1, A-2) in larger amounts than in the Examples, and the properties of Comparative Example 1 were not notably different from those of Examples 1 and 2. Therefore, according to various exemplary embodiments of the present invention, it can be found that the use of the synthetic resin can be effectively reduced without deterioration of properties. 
     Comparative Example 2 was a resin composition including waste coffee grounds and not including a lubricant, and properties such as bending modulus, Izod impact strength, and the like were deteriorated, and strong odors were emitted therefrom. 
     Comparative Example 3 was a resin composition including bamboo wood powder in lieu of waste coffee grounds, and the tensile strength and Izod impact strength thereof were greatly decreased. 
     Comparative Example 4 was a resin composition not including a modified polypropylene, and the tensile strength and Izod impact strength thereof were greatly decreased. 
     As described hereinbefore, although the exemplary embodiments have been described based on limited examples and drawings, various modifications and variations are possible based on the above description, and will be evident to those of ordinary skill in the art. For example, even if the described techniques are performed in a different order from the described method and/or the described components are coupled or combined in a form different from the described method, or replaced with other components or equivalents, appropriate results can be achieved. Therefore, other embodiments, examples, and equivalents to the claims also fall within the scope of the following claims.