Manufacturing method of cyclically reconstructed multifunctional coffee residue base material

Abstract

The invention relates to the field of coffee ground base materials, in particular to a manufacturing method of a recycled multifunctional coffee ground base material. Comprising the following steps: S1, a pretreatment step: cleaning and drying recovered coffee grounds to obtain pretreated coffee grounds; cleaning, crushing and melt-spinning the recycled drinking PET goblet to obtain regenerated PET fibers; s2, a fiber web forming step, wherein the regenerated PET fibers are made into a fiber web; and S3, an in-situ compounding step: mixing the pretreated coffee grounds with the fiber net, so that the pretreated coffee grounds are in contact with a reactive impregnation liquid and react under a heating condition. The recycled PET and the waste coffee grounds are used as main raw materials in the whole process and are converted into functional materials with high additional value through an innovative process, and deep resource recycling of waste is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coffee grounds substrates, in particular to a manufacturing method of recycled multifunctional coffee grounds substrates. BACKGROUND

[0002] Recycling waste plastics and biomass resources is an important development direction in the field of environmental protection materials. Among them, the recycled polyethylene terephthalate (PET) drinking bottles are cleaned, broken and melted into regenerated fibers, and further processed into non-woven fabrics and other materials, which has become a relatively mature resource technology path. At the same time, coffee grounds, as a kind of organic waste rich in porous structure, have attracted widespread attention due to their natural adsorption and potential antibacterial properties. In the prior art, attempts have been made to use coffee grounds as fillers to introduce them into recycled PET non-woven fabrics and other substrates through physical blending or simple impregnation, in order to give the finished product deodorizing, humidifying and other functions, and realize the synergistic value-added utilization of waste.

[0003] However, such prior art solutions face a series of core problems in practical application. First, coffee grounds and regenerated PET fibers are mainly combined through physical and mechanical action, with weak interfacial bonding force, resulting in a significant decrease in the mechanical strength of the finished substrate when a high proportion of coffee grounds is added, and the coffee grounds are easily detached during subsequent processing or use, affecting product life and functional durability. Second, in order to improve dispersibility and inhibit mold growth, coffee grounds may be pretreated or other chemical additives may be added, but this often cannot fundamentally solve the problem of interfacial compatibility and may introduce new unstable factors. More importantly, simple physical mixing cannot create a stable and controllable functional microenvironment between coffee grounds, fibers and polymer matrix. The natural adsorption function of coffee grounds is difficult to effectively and durably activate and maintain, and its functional release is often intense at the beginning and then rapidly decays, lacking long-term effectiveness and environmental responsiveness. The root cause of these deficiencies is that the existing technology mainly stays at the macro or simple micro mixing level, and fails to achieve stable and intelligent combination of coffee grounds functional components and regenerated PET fiber matrix at the molecular scale.

[0004] Therefore, it is of significant technical value and application significance to develop a new manufacturing method that can achieve high-strength, long-term stable combination of coffee grounds and regenerated PET fibers, and effectively regulate the long-term, intelligent release of coffee grounds functions. SUMMARY

[0005] The present application aims to at least overcome one deficiency in the prior art, and provides a manufacturing method of recycled multifunctional coffee grounds substrates.

[0006] To achieve the above-mentioned purpose, the present application discloses a manufacturing method of recycled multifunctional coffee grounds substrates, comprising the following steps:

[0007] S1: a pretreatment step, cleaning and drying the recycled coffee grounds to obtain pretreated coffee grounds; cleaning, crushing and melt spinning the recycled polyethylene terephthalate drinking plastic barrels to obtain regenerated PET fibers;

[0008] S2: a fiber web forming step, making the regenerated PET fibers into a fiber web;

[0009] S3: an in-situ compounding step, mixing the pretreated coffee grounds with the fiber web, making them contact with a reactive impregnating liquid and reacting under heating conditions; wherein the reactive impregnating liquid contains a functional high polymer prepolymer and a silane coupling agent; the reaction makes the functional high polymer prepolymer crosslink into a functional high polymer network, and makes the functional high polymer network form chemical bond connection with the surface of the pretreated coffee grounds and the surface of the regenerated PET fibers through the silane coupling agent, thereby integrating the three into an integrated substrate body.

[0010] The above basic technical solution creatively solves the problems of difficult stable holding of high content coffee grounds in the regenerated PET fiber network and easy functional decay through step design. The core lies in step S3, through the introduction of a specific reactive impregnating liquid and heating reaction, not only the functional high polymer prepolymer is crosslinked into a network, more importantly, the chemical bond connection between the functional high polymer network and the coffee grounds and the regenerated PET fibers is established at the molecular level by the action of the silane coupling agent. This chemical bonding method fundamentally strengthens the interfacial bonding force between the components, so that the coffee grounds particles are firmly anchored in the fiber network and are not easy to fall off during use, and the formed functional high polymer network covers and protects the coffee grounds, so that its natural adsorption function can be long-acting and stable, and finally an integrated substrate with stable structure and long-lasting function is obtained.

[0011] Preferably, in one embodiment, the cleaning and drying treatment of coffee grounds in step S1 includes: heat treatment of coffee grounds at 200-350°C under inert atmosphere or vacuum environment to partially carbonize or activate them. This heat treatment process not only removes moisture completely and inhibits mold growth, but also generates more abundant microporous structure and oxygen-containing functional groups on the surface of coffee grounds. This not only significantly improves the subsequent adsorption capacity of coffee grounds for harmful gases, but more importantly, these increased surface functional groups provide more active sites for chemical reaction with silane coupling agent in subsequent step S3, thereby further enhancing the strength and density of interfacial chemical bonding.

[0012] Further, in one embodiment, the functional polymer prepolymer in step S3 comprises a temperature-sensitive polymer segment or a hydrophilic polymer segment. The introduction of such segments endows the final functional polymer network with environmental response characteristics. The temperature-sensitive segment can reversibly swell or shrink with temperature changes, thereby intelligently adjusting the air permeability and functional release rate of the substrate; the hydrophilic segment helps to regulate the moisture absorption and moisture release performance of the substrate, providing a suitable microenvironment for the functional performance of the coffee grounds.

[0013] Further, in one embodiment, the functional polymer prepolymer is a polyurethane prepolymer containing poly-N-isopropyl acrylamide segments, or a polyol-type prepolymer containing oxirane segments. The prepolymer containing poly-N-isopropyl acrylamide segments is a preferred material for preparing a temperature-sensitive functional network, with a phase transition temperature near the comfortable temperature range of the human body, making it very suitable for indoor environments. The prepolymer containing oxirane segments is a reliable choice for imparting excellent hydrophilicity and humidity response capability to the network.

[0014] Preferably, in another embodiment, the silane coupling agent in step S3 is an isocyanate silane or an epoxy silane. These two types of silane coupling agents can efficiently react with the hydroxyl groups on the surface of the coffee grounds and PET fibers to form covalent bonds on one end, and can hydrolyze and condense or react with the functional polymer prepolymer on the other end, thereby firmly bridging the organic and inorganic interfaces and serving as key reagents for achieving stable chemical bonding.

[0015] Preferably, in one embodiment, the amount of pre-processed coffee grounds added in step S3 is such that the mass percentage of coffee grounds in the final substrate body is 30% to 60%. This addition amount ensures that the coffee grounds occupy a sufficiently high proportion in the substrate, allowing its deodorizing, adsorbing, and other functional properties to be fully realized. At the same time, through the aforementioned chemical bonding technology, the substrate can maintain good structural integrity and mechanical properties even at this high filling amount, overcoming the defect of a sharp decrease in strength at high filling amounts in traditional physical mixing methods.

[0016] Preferably, in another embodiment, the method of contacting in step S3 is dipping or calendering. These two methods are effective means for ensuring that the reactive dipping solution penetrates the fiber web and coffee grounds mixture sufficiently and uniformly, ensuring that the subsequent in-situ reaction occurs uniformly throughout the material, thereby obtaining a substrate product with uniform performance.

[0017] Preferably, in one embodiment, the method of forming a fiber web in step S2 is a dry or wet non-woven fabric forming process. Both of these are mature and efficient fiber web forming technologies that can conveniently produce a fiber web with a three-dimensional network structure from recycled PET fibers, providing an ideal carrier for the subsequent compounding step.

[0018] Further, in one of the embodiments, a step S4 of post-processing is further included, i.e. a raising process is performed on the integrated substrate body to form a raised surface on at least one surface thereof. The raising process can significantly increase the surface area of the substrate, which not only facilitates the volatilization and exchange of coffee grounds functional substances and improves the air purification efficiency, but also endows the substrate with a softer hand feeling and better texture, while providing a better adhesion surface for subsequent embossing, printing or lamination with other materials, greatly expanding the application adaptability of the substrate in the soft furnishing field such as high-end wallpaper and decorative fabric.

[0019] The above-listed benefits are not exhaustive of all advantages. Other potential benefits and detailed technical implementations will be further disclosed in the embodiments or other description parts of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a workflow diagram of the present disclosure. DETAILED DESCRIPTION

[0021] The present disclosure will be described with reference to the accompanying drawings, which show several embodiments of the present disclosure. It should be understood, however, that the present disclosure can be presented in many different forms and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and to fully inform those skilled in the art of the scope of protection of the present disclosure. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.

[0022] It should be understood that, in all the drawings, the same reference signs represent the same elements. In the drawings, the dimensions of certain features can be distorted for the sake of clarity.

[0023] It should be understood that the language used in the specification is only used to describe specific embodiments and is not intended to limit the present disclosure. Unless otherwise defined, all terms (including technical and scientific terms) used in the specification have meanings commonly understood by those skilled in the art. For the sake of brevity and / or clarity, techniques, methods and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the authorized description when appropriate.

[0024] As used in the specification, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. As used in the specification, the language "comprises", "comprising", and "including" means the presence of the stated feature but does not exclude the presence of one or more other features. As used in the specification, the language "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] Example 1

[0026] The present embodiment provides a method for manufacturing a recycled multi-functional coffee grounds-based substrate, and the specific steps are as follows:

[0027] S1: Pretreatment step.

[0028] First, the brewed coffee grounds are collected, rinsed with clean water to remove residual sugar and oil, and then dried in an oven at 105°C to a constant weight to obtain dried coffee grounds. The dried coffee grounds are placed in a tube furnace, heated to 250°C at a rate of 5°C / min under a nitrogen protective atmosphere, and held at this temperature for 60 minutes. After natural cooling, the pretreated coffee grounds with partially carbonized surface, rich in micropores and oxygen-containing functional groups are obtained.

[0029] At the same time, the recycled PET beverage bottles are sorted, washed, and crushed to obtain PET fragments. The PET fragments are melted and then prepared into recycled PET short fibers by a spinning machine.

[0030] S2: Fiber web forming step.

[0031] The recycled PET short fibers are opened and carded, and then laid into a fiber web with a grammage of 80 g / m² using a dry non-woven forming process.

[0032] S3: In-situ compounding step.

[0033] Prepare the reactive impregnation solution: take 100 parts by weight of polyurethane prepolymer (40% solid content aqueous dispersion) containing poly-N-isopropyl acrylamide (PNIPAM) temperature-sensitive segment in the molecular chain, add 3 parts by weight of γ-isocyanate propyl triethoxysilane as a silane coupling agent, and add 200 parts by weight of deionized water, and stir uniformly.

[0034] The pretreated coffee grounds obtained in S1 are calculated at a target mass percentage of 50% (based on the dry weight of the final substrate) and evenly scattered into the fiber web prepared in S2, and the coffee grounds are preliminarily dispersed by mechanical kneading.

[0035] The fiber web mixed with coffee grounds is immersed in the above-mentioned reactive impregnation solution, and the liquid rate is controlled to be 100% by roller pressing. Then the impregnated material is transferred to an oven and heated at 100°C for 45 minutes. In this process, the polyurethane prepolymer crosslinks and solidifies to form a three-dimensional network, and the silane coupling agent reacts with the hydroxyl groups on the surface of the pretreated coffee grounds, the polar groups on the surface of the PET fibers, and the polyurethane network to form covalent bonds, and finally a integrated and structurally stable coffee grounds composite substrate blank is obtained.

[0036] S4: Post-treatment step.

[0037] The cooled substrate blank is subjected to single-side raising treatment by a steel wire raising machine, the raising depth is controlled, and a uniform short and dense pile surface is formed, i.e. the recycled multifunctional coffee grounds substrate is prepared. The test shows that the mass percentage of coffee grounds in the substrate is about 48%, the hand feeling is soft, and the substrate has good temperature-sensitive air permeability.

[0038] Example 2

[0039] The main difference between this embodiment and Example 1 is the pretreatment method of coffee grounds and the selection of functional polymer prepolymer, so as to show different preferred schemes of the application.

[0040] S1: In the pretreatment step, the heat treatment conditions of the dried coffee grounds are changed as follows: heat treatment at 300°C for 30 minutes under vacuum to obtain pretreated coffee grounds with higher activation. The regenerated PET fiber is prepared as in Example 1.

[0041] S2: As in Example 1.

[0042] S3: In the in-situ compounding step, the preparation of the reactive impregnating solution is changed as follows: 100 parts by weight of polyurethane prepolymer (solid content of 35%) containing polyethylene oxide (PEO) hydrophilic segment is taken, 4 parts by weight of γ-(2,3-epoxypropoxy) propyl trimethoxysilane is added as a silane coupling agent, and 150 parts by weight of deionized water is added and stirred uniformly.

[0043] The pretreated coffee grounds are mixed with the fiber web at a target mass percentage of 40%, the impregnating solution is applied by rolling, and the liquid retention rate is controlled at 80%. Then, the in-situ compounding reaction is completed by heating at 85°C for 60 minutes.

[0044] S4: In this embodiment, the formed substrate body is not subjected to raising treatment, and is directly wound as a flat non-woven fabric substrate. The test shows that the substrate has excellent hydrophilic and moisture absorption properties and stable structure.

[0045] Example 3

[0046] This embodiment aims to show another preferred combination of coffee grounds addition ratio and forming process.

[0047] S1: As in Example 1.

[0048] S2: In the fiber web forming step, a wet non-woven fabric forming process is used. The regenerated PET staple fiber and part of the pretreated coffee grounds (20% of the total coffee grounds) are dispersed in water, and are jointly beaten to form a fiber / coffee grounds mixed wet web, and then are dehydrated and pre-dried.

[0049] S3: The remaining 80% of the pre-processed coffee grounds were evenly spread on the pre-dried mixed wet web. The same reactive impregnating solution as in Example 1 was prepared and evenly applied to the surface of the material using a spraying method. Subsequently, the reaction was heated at 110°C for 40 minutes, and the total amount of coffee grounds added reached 35% of the dry weight of the substrate.

[0050] S4: The same as Example 1, the napping treatment was carried out.

[0051] Beneficial effects

[0052] From the above examples, it can be seen that the manufacturing method provided by the present application has the following significant advantages:

[0053] 1. High stability and high content compatibility: The chemical bonding interface formed by in-situ chemical reaction makes the coffee grounds firmly combined with the regenerated PET fibers. Even at a high addition ratio of 30%-60%, the substrate still maintains good mechanical strength and structural integrity, and the coffee grounds are not easily detached.

[0054] 2. Long-term function and intelligence: The construction of functional polymer networks (such as temperature-sensitive and hydrophilic) not only fixes the coffee grounds but also provides a controlled microenvironment for their functional performance. For example, the temperature-sensitive network can intelligently adjust the air permeability according to the temperature, thereby controlling the desorption and regeneration process of the coffee grounds adsorbed substances, achieving long-term function and responsive release.

[0055] 3. Strong process adaptability: The method is compatible with dry and wet webbing, as well as impregnation, rolling, spraying and other composite methods, and can be flexibly produced by including or not including the napping post-treatment step to produce functional substrates suitable for different end products (such as filter materials, wallpaper base, decorative fabrics).

[0056] 4. Environmental protection and high value: The present application uses recycled PET and waste coffee grounds as the main raw materials throughout the process, and through innovative processes, it converts them into high-value functional materials, achieving deep resource recycling of waste.

[0057] The following will describe the working process and technical advantages of the coffee ground substrate prepared by the method of the present application as an indoor decorative wallpaper material in actual environment.

[0058] Suppose the substrate (such as the napped product prepared in Example 1) is used as a decorative layer or intermediate functional layer to prepare a wallpaper, which is applied to the wall surface of a newly renovated living room. The room continuously releases low concentrations of formaldehyde, toluene and other volatile organic compounds (VOCs) due to furniture, paint, etc., and the indoor humidity fluctuates with the weather and personnel activities.

[0059] At the initial stage of wall paper pasting, the high content of coffee grounds particles (about 48% by mass) in the substrate, which are firmly anchored by chemical bonds, begin to exhibit their porous adsorption properties. Their large specific surface area and activated surface can effectively adsorb VOCs molecules such as formaldehyde in the air.

[0060] The technical advantages are embodied in that: due to the stable chemical bond formed between the coffee grounds, PET fibers and functional polymer network through silane coupling agent, even in the process of rubbing and stretching during wall paper pasting, or slight touch during daily cleaning, the coffee grounds particles are rarely detached, avoiding the common "powder falling" problem of traditional physical mixed materials, ensuring the service life of the product and the indoor cleanliness, and at the same time ensuring that the high load of functional fillers can actually and durably play a role.

[0061] As the indoor temperature rises due to sunlight or heating (for example, from 20°C to 28°C), the temperature-sensitive polyurethane network (containing PNIPAM segments) in the substrate changes its structure, the chain segment movement intensifies, the network micropores expand, and the vapor transmission rate significantly increases. This change has a double effect: on the one hand, VOCs molecules adsorbed in the pores of coffee grounds and inside the network are more easily desorbed and diffuse into the network, and then released back into the air through the increased micropores; but on the other hand, more importantly, the technical advantages are embodied in that: this process is not a simple and uncontrollable release, but promotes the local regeneration of coffee grounds adsorption sites under the action of network "breathing", and creates dynamic balance conditions for subsequent continuous adsorption. At the same time, the change of network structure also adjusts the transmission of moisture, which helps to maintain the air permeability of the wall. This intelligent response to environmental temperature changes the functional release of the substrate from passive and static to active and dynamic, prolonging its effective purification period.

[0062] In long-term use, the environmental humidity may increase. The functional polymer network in the substrate, due to its specific hydrophilic / microporous structure, allows water molecules to pass through in the form of vapor, but can block liquid water, thereby reducing the risk of mold growth in coffee grounds due to direct moisture. The technical advantages are embodied in that: this is due to the dense network structure formed in situ, which uniformly coats the coffee grounds, acting as a persistent and stable "protective shell" that physically isolates most direct effects of adverse environmental factors. Compared with technologies that only use surface coatings or simply add mold inhibitors through simple mixing, this protection is more fundamental and persistent, and does not rely on chemical additives that may migrate or fail, providing better safety and durability.

[0063] In this scenario, the wallpaper substrate is not a passive decorative layer, but a "live" system that achieves structural stability through chemical bonding technology and functional dynamic regulation through intelligent polymer networks. It continuously, stably and intelligently performs air purification and micro-environment regulation functions, with three core technical advantages of high load stability, long-term functionality and environmental responsiveness, which are fully embodied under real and complex use conditions, effectively solving the core pain points of traditional similar materials such as short-term functionality, easy failure and poor maintenance.

[0064] While exemplary embodiments of the present disclosure have been described, it will be understood by those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the present disclosure in its broadest form. Therefore, all changes and modifications are intended to be included within the scope of the present disclosure as defined in the appended claims. The present disclosure is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a recyclable multifunctional coffee grounds substrate, characterized in that, Includes the following steps: S1: Pre-treatment step, cleaning and drying the recycled coffee grounds to obtain pre-treated coffee grounds; washing, crushing and melt spinning the recycled polyethylene terephthalate drinking bottles to obtain recycled PET fibers; S2: Fiber web forming step, wherein the recycled PET fibers are formed into a fiber web; S3: In-situ composite step, the pretreated coffee grounds are mixed with the fiber web, and then contacted with a reactive impregnation liquid and reacted under heating conditions; wherein, the reactive impregnation liquid contains a functional polymer prepolymer and a silane coupling agent; the reaction causes the functional polymer prepolymer to crosslink to form a functional polymer network, and the functional polymer network forms chemical bonds with the surface of the pretreated coffee grounds and the surface of the recycled PET fiber through the silane coupling agent, thereby combining the three into an integrated substrate body.

2. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 1, characterized in that, In step S1, the cleaning and drying process of coffee grounds includes: heat-treating the coffee grounds at 200°C to 350°C in an inert atmosphere or vacuum environment to partially carbonize or activate them.

3. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 1, characterized in that, In step S3, the functional polymer prepolymer contains thermosensitive polymer segments or hydrophilic polymer segments.

4. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 3, characterized in that, The functional polymer prepolymer is a polyurethane prepolymer containing poly(N-isopropylacrylamide) segments, or a polyol prepolymer containing ethylene oxide segments.

5. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 1, characterized in that, In step S3, the silane coupling agent is an isocyanate-based silane or an epoxy-based silane.

6. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 1, characterized in that, In step S3, the amount of pretreated coffee grounds added is such that its mass percentage in the final substrate body is 30% to 60%.

7. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 1, characterized in that, In step S3, the contact method is impregnation or rolling.

8. The method for manufacturing the recycled multifunctional coffee grounds substrate according to claim 1, characterized in that, In step S2, the fiber web is formed by a dry or wet nonwoven fabric forming process.

9. The method for manufacturing the recycled multifunctional coffee grounds substrate according to any one of claims 1 to 8, characterized in that, It also includes step S4: a post-processing step, which involves napping the integrated substrate body to form a napped surface on at least one of its surfaces.

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