Preparation method and application of aroma-carrying paper-based material

Abstract

The invention relates to a preparation method and application of a fragrance-carrying paper-based material. The preparation method comprises the following steps: carrying out epoxidation modification on papermaking plant pulp; mixing the epoxidized modified plant pulp with a phenolic flavor substance and a catalyst, and carrying out thermal reaction to obtain phenolic flavor substance grafted plant pulp; the phenolic flavor substance is selected from any one or a combination of at least two of eugenol, guaiacol or maltol; and papermaking by taking the phenolic flavor substance grafted plant pulp as a raw material. According to the method provided by the invention, a specific fragrant substance is firmly connected to a cellulose skeleton through a covalent bond, so that long-acting slow release of fragrance can be realized, and the physical properties and combustion characteristics of the paper-based material can be improved.

Description

Technical Field

[0001] This invention belongs to the field of functional paper-based materials technology, and relates to a method for preparing a fragrance-loaded paper-based material and its application. Background Technology

[0002] Cellulose is the most abundant natural polymer in the world, derived from plants such as wood, cotton, bamboo, and hemp, and is a basic raw material for the paper industry. With technological advancements and consumption upgrades, the market's demand for functional paper products is growing, no longer limited to traditional packaging and writing uses, but expecting them to possess special functions such as slow-release fragrance, antibacterial properties, and enhanced mechanical properties. Among these, the development of fragrance-loaded paper-based materials with long-lasting fragrance retention shows broad application prospects in high-end packaging, decorative paper, cultural and creative products, and household goods.

[0003] Currently, the mainstream technologies for scenting paper products mainly include physical coating, blending and addition, and microencapsulation. Physical coating involves directly spraying or impregnating fragrances onto the surface of the finished paper. This method is simple, but the fragrance substances rely solely on physical adsorption to the fiber surface, resulting in weak binding and easy volatilization during processing and storage, leading to short-lasting fragrance and potential uneven fragrance distribution due to migration. Blending involves adding fragrances to the pulp during the pulping stage. While this method allows some fragrance substances to remain within the paper, a large amount of heat-sensitive fragrance substances will escape or decompose during subsequent wet-end, drying, and calendering processes, resulting in low utilization and poor persistence. Microencapsulation technology encapsulates fragrances through wall materials, protecting the core material to some extent and slowing the release rate. However, its preparation process is relatively complex and costly, and the stability, encapsulation rate, and mechanical stress resistance of the wall materials after bonding with paper still face challenges.

[0004] These traditional methods all share a common fundamental flaw: the fragrance substances and cellulose fibers are mainly bound by weak interactions such as van der Waals forces and physical adsorption, failing to form strong chemical bonds. This unstable binding mode directly leads to problems such as low fragrance retention, poor durability, and susceptibility to environmental factors (temperature, humidity), severely restricting the development of high-end, long-lasting scented paper products.

[0005] Therefore, developing a new technological strategy to directly graft fragrance molecules onto the cellulose backbone by constructing strong chemical bonds, thereby fundamentally solving the problems of volatility and migration of fragrance substances, is of great significance for promoting the innovative development of functional paper-based materials. This technology can not only achieve controllable and sustained fragrance release, but may also endow paper with superior physical properties due to changes in molecular structure, providing new solutions for developing next-generation high-performance paper products. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing a fragrance-loaded paper-based material and its application.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a fragrance-loaded paper-based material, the method comprising the following steps:

[0009] (1) Epoxidation modification of papermaking plant pulp;

[0010] (2) The epoxidized plant pulp is mixed with phenolic aroma substances and a catalyst and subjected to a thermal reaction to obtain phenolic aroma substances grafted plant pulp; the phenolic aroma substances are selected from any one or at least a combination of two of eugenol, guaiacol or maltol.

[0011] (3) Papermaking is carried out using phenolic fragrance substances grafted plant pulp as raw material to obtain fragrance-loaded paper base material.

[0012] The method involved in this invention is to firmly attach a specific fragrance substance, namely any one or at least two combinations of eugenol, guaiacol, or maltol, to plant fibers via covalent bonds. This method not only achieves long-lasting sustained release of fragrance, effectively overcoming the problems of easy volatility and short fragrance retention time of traditional physical addition methods, but also the chemical modification of cellulose is expected to improve other properties of paper-based materials, such as physical properties (tear resistance and air permeability) and combustion properties (reduced tar and harm), providing a new technical approach for the development of novel functional paper-based materials.

[0013] Preferably, the plant pulp in step (1) includes any one or a combination of at least two of the following: broadleaf wood pulp, softwood pulp, grass pulp, bamboo pulp, cotton pulp, or hemp pulp.

[0014] Preferably, the modifier used in step (1) for epoxidation modification is selected from any one or a combination of at least two of epichlorohydrin, epibromopropane, or dimethyl carbonate.

[0015] Preferably, the epoxidation modification method in step (1) includes:

[0016] Papermaking plant pulp is mixed with strong alkaline solution and epoxidation modifier, and reacted at 50-70℃ (e.g., 50℃, 55℃, 60℃, 65℃, 70℃, etc.) for 3-8 hours (e.g., 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.). After washing, epoxidation modified plant pulp is obtained.

[0017] Preferably, the strong alkaline solution includes a NaOH solution.

[0018] Preferably, the ratio of the plant pulp to the strong alkaline solution, calculated as oven-dry pulp, is 1:(15-35)g / mL, for example, 1:15g / mL, 1:18g / mL, 1:20g / mL, 1:22g / mL, 1:25g / mL, 1:30g / mL, 1:35g / mL, etc.

[0019] Preferably, the ratio of the plant pulp to the epoxidizing agent, based on oven-dry pulp, is 1:(1-8) g / mL, for example, 1:1 g / mL, 1:2 g / mL, 1:3 g / mL, 1:3.5 g / mL, 1:4 g / mL, 1:4.5 g / mL, 1:5 g / mL, 1:5.5 g / mL, 1:6 g / mL, 1:7 g / mL, 1:8 g / mL, etc.

[0020] Preferably, the washing uses ethanol and / or water.

[0021] Preferably, the mass ratio of the epoxidized plant pulp to the phenolic flavoring substance in step (2) is 1:(1-15), for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, etc.

[0022] Preferably, the catalyst in step (2) comprises an organic base catalyst.

[0023] Preferably, the organic base catalyst is selected from pyridine compounds or triethylamine.

[0024] Preferably, the pyridine compound is selected from any one or a combination of at least two of 4-dimethylaminopyridine, 4-pyrrolidinylpyridine, or 4-tert-butylpyridine.

[0025] Preferably, the thermal reaction in step (2) is carried out at 50-70℃ (e.g., 50℃, 55℃, 60℃, 65℃, 70℃, etc.) for 4-8 hours (e.g., 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 7 hours, 7.5 hours, 8 hours, etc.).

[0026] Preferably, after the thermal reaction in step (2) is completed, cooling, filtration and drying are also performed.

[0027] Preferably, the phenolic flavoring substance is selected from a combination of eugenol and maltol.

[0028] This invention also creatively discovers that when eugenol and maltol are co-grafted and covalently modified, the improvement in aroma stability, physical properties (tear resistance and air permeability), and combustion properties (reduced tar and harm) is even more outstanding.

[0029] Preferably, the mass ratio of eugenol to maltol is 1:(1-4), such as 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, etc.

[0030] Preferably, the raw materials used in step (3) of papermaking also include ungrafted plant pulp, which includes any one or a combination of at least two of the following: broadleaf wood pulp, softwood pulp, straw pulp, bamboo pulp, cotton pulp, or hemp pulp.

[0031] Preferably, the raw materials used in step (3) of papermaking also include calcium carbonate, more preferably light calcium carbonate.

[0032] Preferably, the calcium carbonate accounts for 30-35% of the total weight of the raw materials, such as 30%, 31%, 32%, 33%, 34%, 35%, etc.

[0033] Preferably, the raw materials used in step (3) of papermaking also include citrate.

[0034] Preferably, the citrate comprises potassium citrate and / or sodium citrate.

[0035] Other values ​​not listed above within the range of values ​​can be selected and are all within the protection scope of this invention. Considering the brevity of the discussion, they will not be elaborated on here.

[0036] In this invention, step (3) of papermaking includes: mixing all the raw materials used for papermaking and then performing a loosening treatment, followed by papermaking treatment, and drying the paper sheets obtained after filtration under flattening conditions.

[0037] Secondly, the present invention provides an application of a fragrance-loaded paper-based material prepared by the method described in the first aspect in functional paper products.

[0038] Preferably, the functional paper products include, but are not limited to, packaging paper, decorative paper, or other high-grade paper products with long-lasting, slow-release fragrance.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention uses covalent bonding to firmly attach specific fragrance substances to the plant fiber skeleton, achieving a stable bond between fragrance molecules and the fiber matrix. This chemical bonding strategy can significantly improve fragrance retention and achieve a long-lasting, sustained-release fragrance function, overcoming the technical bottlenecks of easy fragrance evaporation and short fragrance retention time in traditional physical coating or blending methods.

[0041] Meanwhile, chemical modification of cellulose effectively improves the overall performance of the material: on the one hand, it enhances the material's mechanical strength and durability; on the other hand, it regulates the material's pore structure and air permeability through molecular structure design. Furthermore, the modified fiber material exhibits unique thermal decomposition characteristics during thermal processing, providing an innovative solution for developing novel functional paper-based materials. Attached Figure Description

[0042] Figure 1 The infrared spectrum of the eugenol-grafted hardwood pulp prepared in Example 1 is shown.

[0043] Figure 2 The infrared spectrum of the guaiacol-grafted hardwood pulp prepared in Example 2 is shown.

[0044] Figure 3 The infrared spectrum of the maltol-grafted hardwood pulp prepared in Example 3 is shown.

[0045] Figure 4 This is a graph showing the analysis results of the pyrolysis products of the paper-based material prepared in Comparative Example 1.

[0046] Figure 5 This is a graph showing the analysis results of the thermal pyrolysis products of the paper-based material prepared in Example 3. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0048] Preparation Example 1

[0049] This preparation example provides an eugenol-grafted hardwood pulp, prepared by the following method:

[0050] (1) Mix 10g of oven-dried hardwood pulp with 250mL of 50% NaOH solution until homogeneous, add 30mL of epichlorohydrin, and stir at 40℃ for 5h. Wash twice with anhydrous ethanol and filter, then wash with deionized water until neutral, and finally wash twice with anhydrous ethanol to obtain epoxidized hardwood pulp.

[0051] (2) Add 10g of epoxidized hardwood pulp, 100g of eugenol and 3g of catalyst DMAP (3wt.%) to a 1000mL round-bottom flask. After reacting at 60°C for 6 hours under magnetic stirring, cool the reactor to 25°C, filter and dry to obtain hardwood pulp grafted with eugenol.

[0052] Infrared characterization was performed on eugenol-grafted hardwood pulp and ungrafted hardwood pulp, such as... Figure 1As shown in the figure, the curve (red) for grafting eugenol onto broadleaf wood pulp reaches a wavenumber of 1360.3 cm⁻¹. -1 The peak appearing at [location] corresponds to the =COC stretching vibration peak of the aromatic ether, indicating the presence of an aromatic ether structure in the system after grafting eugenol onto broadleaf wood pulp. This peak is generated by the absorption of infrared light by the =COC bond vibration in the aromatic ether; the wavenumber is 889.7 cm⁻¹. -1 The peak at [location] is an out-of-plane bending vibration peak of benzene trisubstituted, indicating that the structure of eugenol grafted onto hardwood pulp contains a benzene ring in a trisubstituted form. In contrast, hardwood pulp (black curve) does not have these two characteristic peaks, suggesting that grafting eugenol onto hardwood pulp introduces an aromatic ether structure and a trisubstituted benzene ring structure, resulting in a chemical structure different from that of hardwood pulp.

[0053] Preparation Example 2

[0054] This preparation example provides a guaiacol-grafted hardwood pulp, prepared by the following method:

[0055] (1) Mix 10g of oven-dried hardwood pulp with 250mL of 50% NaOH solution until homogeneous, add 30mL of epichlorohydrin, and stir at 40℃ for 5h. Wash twice with anhydrous ethanol and filter, then wash with deionized water until neutral, and finally wash twice with anhydrous ethanol to obtain epoxidized hardwood pulp.

[0056] (2) Add 10g of epoxidized hardwood pulp, 100g of guaiacol and 3g of catalyst DMAP (3wt.%) to a 1000mL round-bottom flask. After reacting at 60°C for 6 hours with magnetic stirring, cool the reactor to 25°C, filter and dry to obtain hardwood pulp grafted with guaiacol.

[0057] Infrared characterization was performed on guaiacol-grafted hardwood pulp and ungrafted hardwood pulp, such as... Figure 2 As shown in the figure, grafting guaiacol onto broadleaf wood pulp (red curve) results in a high wavenumber of 1060.5 cm⁻¹. -1 1220.3cm -1 Infrared absorption peaks appeared at [location missing]. These two absorption peaks are due to the =COC stretching vibration of aryl ethers, indicating the presence of aryl ether structures in the system after grafting guaiacol onto hardwood pulp. Furthermore, guaiacol grafted onto hardwood pulp showed an infrared absorption peak at a wavenumber of 1530.3 cm⁻¹. -1 and 1510.6cm -1 The presence of distinct absorption peaks at all positions, consistent with the standard values ​​for benzene ring skeletal vibration peaks, confirms the presence of a benzene ring in its structure. In contrast, hardwood pulp (black curve) does not exhibit such a distinct characteristic peak at the corresponding wavenumber positions, indicating that the grafting of guaiacol into hardwood pulp introduces a benzene ring structure, resulting in a chemical structure different from that of pure hardwood pulp.

[0058] Preparation Example 3

[0059] This preparation example provides a maltol-grafted hardwood pulp, prepared by the following method:

[0060] (1) Mix 10g of oven-dried hardwood pulp with 250mL of 50% NaOH solution until homogeneous, add 30mL of epichlorohydrin, and stir at 40℃ for 5h. Wash twice with anhydrous ethanol and filter, then wash with deionized water until neutral, and finally wash twice with anhydrous ethanol to obtain epoxidized hardwood pulp.

[0061] (2) Add 10g of epoxidized hardwood pulp, 100g of maltol and 3g of catalyst DMAP (3wt.%) to a 1000mL round-bottom flask. After reacting at 60°C for 6 hours with magnetic stirring, cool the reactor to 25°C, filter and dry to obtain maltol-grafted hardwood pulp.

[0062] Infrared characterization was performed on maltol-grafted hardwood pulp and ungrafted hardwood pulp, such as... Figure 3 As shown in the figure, maltol grafted onto broadleaf wood pulp (red curve) is present at 1631.3 cm. -1 An absorption peak appears at 1459.9 cm⁻¹, corresponding to the C=C stretching vibration peak of the alkene; [the peak appears at 1459.9 cm⁻¹]. -1 1426.3cm -1 The presence of an absorption peak, consistent with the standard value of the bending vibration peak of =CH2, further confirms the presence of the =CH2 group structure in the system. These characteristic peaks indicate that grafting maltol onto hardwood pulp introduces structural fragments containing olefins and =CH2 groups, resulting in a significant alteration in the chemical structure compared to hardwood pulp (black curve).

[0063] Preparation Example 4

[0064] This preparation example provides an eugenol-grafted softwood pulp, prepared by the following method:

[0065] (1) Mix 10g of oven-dried softwood pulp with 300mL of 50% NaOH solution until homogeneous, add 40mL of epoxide-bromopropane, and stir at 50℃ for 4h. Wash twice with anhydrous ethanol and filter, then wash with deionized water until neutral, and finally wash twice with anhydrous ethanol to obtain epoxidized softwood pulp.

[0066] (2) Add 10g of epoxidized softwood pulp, 100g of eugenol and 3g of catalyst 4-pyrrolylpyridine (3wt.%) to a 1000mL round-bottom flask. After reacting at 70℃ for 4 hours under magnetic stirring, cool the reactor to 25℃, filter and dry to obtain eugenol-grafted softwood pulp.

[0067] Preparation Example 5

[0068] This preparation example provides a maltol-grafted softwood pulp, prepared by the following method:

[0069] (1) Mix 10g of oven-dried softwood pulp with 200mL of 50% NaOH solution until homogeneous, add 20mL of epichlorohydrin, and stir at 35℃ for 7h. Wash twice with anhydrous ethanol and filter, then wash with deionized water until neutral, and finally wash twice with anhydrous ethanol to obtain epoxidized softwood pulp.

[0070] (2) Add 10g of epoxidized softwood pulp, 77g of maltol and 3g of catalyst 4-tert-butylpyridine (3wt.%) to a 1000mL round-bottom flask. After reacting at 55°C for 7 hours with magnetic stirring, cool the reactor to 25°C, filter and dry to obtain maltol-grafted softwood pulp.

[0071] Preparation Example 6

[0072] This preparation example provides a composite grafted hardwood pulp containing eugenol and maltol, prepared by the following method:

[0073] (1) Mix 10g of oven-dried hardwood pulp with 250mL of 50% NaOH solution until homogeneous, add 30mL of epichlorohydrin, and stir at 40℃ for 5h. Wash twice with anhydrous ethanol and filter, then wash with deionized water until neutral, and finally wash twice with anhydrous ethanol to obtain epoxidized hardwood pulp.

[0074] (2) Add 10g of epoxidized hardwood pulp, 65g of eugenol, 35g of maltol and 3g of catalyst DMAP (3wt.%) to a 1000mL round-bottom flask. After reacting at 60°C for 6 hours under magnetic stirring, cool the reactor to 25°C, filter and dry to obtain hardwood pulp grafted with eugenol and maltol.

[0075] Test Example 1

[0076] The yield and degree of substitution of the phenolic grafted wood pulps prepared in Examples 1-6 were calculated.

[0077] The formula for calculating yield is:

[0078] Where m 木浆 For the quality of wood pulp before grafting, m 改性纤维素 The quality of the wood pulp after grafting.

[0079] The degree of substitution of the long-chain esters in the product was determined by elemental analysis. The formula for calculating the degree of substitution is as follows:

[0080]

[0081] Where DS represents the degree of substitution; M 木浆M is the molar mass of the wood pulp glucoside aglycone; 改性纤维素 X is the molar mass of the modified cellulose glucosinolate; 木浆 X represents the carbon content in wood pulp. 改性纤维素 X represents the carbon content in the modified cellulose glucosinolate. 样品 The total C content of the modified cellulose sample.

[0082] The results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] Examples 1-3

[0087] Paper-based materials were prepared using the phenolic grafted hardwood pulp obtained in Preparation Examples 1-3. The specific method was as follows: 42% (freeness 30) of phenolic grafted hardwood pulp obtained in Preparation Examples 1-3, 18% (freeness 80) of ungrafted softwood pulp, 33% of light calcium carbonate, 3% of potassium citrate, and 4% of sodium citrate were blended. The blended pulp was poured into a fiber disintegrator, and the speed of the disintegrator was set to 8000 rpm to dissolve the mixed fiber pulp. Then, papermaking was carried out. The paper sheets obtained were dried at 90°C for 20 min under flattening conditions and vacuum of -0.05 MPa to obtain finished paper samples. The obtained paper samples were equilibrated for 24 h under constant temperature and humidity conditions of 23°C and 50% relative humidity.

[0088] Examples 4-5

[0089] Paper-based materials were prepared using the phenolic-grafted softwood pulp obtained in Preparation Examples 4-5. The specific method was as follows: 18% (freezing degree of 80) of phenolic-grafted softwood pulp obtained in Preparation Examples 4-5, 42% (freezing degree of 30) of ungrafted hardwood pulp, 33% of light calcium carbonate, 3% of potassium citrate, and 4% of sodium citrate were blended. The blended pulp was poured into a fiber disintegrator, and the speed of the disintegrator was set to 8000 rpm to dissolve the mixed fiber pulp. Then, papermaking was carried out. The paper sheets obtained were dried at 90°C for 20 min under flattening conditions and vacuum at -0.05 MPa to obtain finished paper samples. The obtained paper samples were equilibrated for 24 h under constant temperature and humidity conditions of 23°C and 50% relative humidity.

[0090] Example 6

[0091] Paper-based materials were prepared using the phenolic-grafted hardwood pulp obtained in Preparation Example 6. The specific method was as follows: 42% (freezing degree 30) of the phenolic-grafted hardwood pulp obtained in Preparation Example 6, 18% (freezing degree 80) of ungrafted softwood pulp, 33% of light calcium carbonate, 3% of potassium citrate, and 4% of sodium citrate were blended. The blended pulp was poured into a fiber disintegrator, and the speed of the disintegrator was set to 8000 rpm to dissolve the mixed fiber pulp. Then, papermaking was carried out. The paper sheets obtained were dried at 90°C for 20 min under flattening conditions and vacuum at -0.05 MPa to obtain finished paper samples. The obtained paper samples were equilibrated for 24 h under constant temperature and humidity conditions of 23°C and 50% relative humidity.

[0092] Comparative Example 1

[0093] Paper-based materials were prepared using ungrafted wood pulp. The specific method was as follows: 42% ungrafted hardwood pulp (freezing degree 30), 18% ungrafted softwood pulp (freezing degree 80), 33% light calcium carbonate, 3% potassium citrate, and 4% sodium citrate were blended. The blended pulp was poured into a fiber disintegrator, and the speed of the disintegrator was set to 8000 rpm to dissolve the mixed fiber pulp. Then, papermaking was carried out. The paper sheets obtained were flattened and dried at 90℃ for 20 minutes under a vacuum of -0.05 MPa to obtain the finished paper sample. The obtained paper sample was equilibrated for 24 hours under constant temperature and humidity conditions of 23℃ and 50% relative humidity.

[0094] Test Example 2

[0095] Evaluation of pyrolysis products:

[0096] The pyrolysis products of the paper-based materials prepared in Example 3 and Comparative Example 1 were compared. Specifically, the pyrolysis products of each sample were analyzed using a pyrolysis gas chromatography-mass spectrometry (GC-MS) system under an Ar atmosphere at 300°C, 600°C, and 900°C, respectively. The results are shown below. Figure 4 (Comparative Example 1) and Figure 5 As shown in Example 3.

[0097] from Figure 4As can be seen, at 300℃, Comparative Example 1 produced 74 pyrolysis products of 12 substances, with acids, alcohols, hydrocarbons, and ketones accounting for a relatively high proportion. At 600℃, Comparative Example 1 produced 10 pyrolysis products of 9 substances, with sugars, inorganic compounds (mainly CO2), and aldehydes accounting for a relatively high proportion. At 900℃, Comparative Example 1 produced 7 pyrolysis products of 4 substances, with amines accounting for the highest proportion, and also produced highly toxic polycyclic aromatic hydrocarbons and benzene compounds. These results indicate that as the pyrolysis temperature increases, the types and quantities of pyrolysis products decrease, but highly toxic polycyclic aromatic hydrocarbons are produced at high-temperature pyrolysis (900℃).

[0098] from Figure 5 As can be seen, at 300℃, the sample of Example 3 produced a total of 79 thermal decomposition products of 12 substances, among which alcohols, ketones and sugars accounted for the highest proportion; when the thermal decomposition temperature was 600℃, the sample of Example 3 produced a total of 11 thermal decomposition products of 6 substances, among which sugars, acids and aldehydes accounted for a relatively high proportion; when the thermal decomposition temperature was 900℃, the sample of Example 3 produced a total of 31 thermal decomposition products of 4 substances, among which amines accounted for the highest proportion at 73.39%.

[0099] The above results indicate that maltol grafting has a significant impact on the pyrolysis products of paper. After maltol grafting, the pyrolysis products of paper change. No harmful substances such as polycyclic aromatic hydrocarbons were detected in the pyrolysis products of paper at 900℃. This result suggests that maltol grafting can play a certain role in reducing tar and harmful substances.

[0100] Test Example 3

[0101] Evaluation of the physical properties of paper-based materials:

[0102] (1) The air permeability of the paper-based material samples prepared in Examples 1-6 and Comparative Example 1 was characterized using a differential pressure gas permeation analyzer, and the standard was GB / T1038. The results are shown in Table 2.

[0103] Table 2

[0104]

[0105]

[0106] As shown in Table 2, compared with Comparative Example 1, the paper-based materials prepared in Examples 1-6 have better air permeability. This indicates that the preparation method of the present invention, which involves firmly attaching any one or at least two of the specific fragrance substances, namely eugenol, guaiacol, or maltol, to the pulp fibers through covalent bonds, can have a positive impact on the air permeability of the paper. Furthermore, the data from Examples 1-3 and Example 6 show that the grafting effect of maltol is relatively better, the grafting effect of eugenol is second best, and the co-grafting effect of maltol and eugenol is the best.

[0107] (2) The maximum tensile force that the paper could withstand before breaking was determined using an electronic universal testing machine. The specific testing process was as follows: The paper was cut into rectangular strips of 5mm × 50mm and fixed vertically on the testing machine. The clamping distance during the tensile test was approximately 25mm, and the tensile rate was 5mm / s. The results are shown in Table 3.

[0108] Table 3

[0109]

[0110]

[0111] As shown in Table 3, compared with Comparative Example 1, the paper-based materials prepared in Examples 1-6 have superior tear resistance. This indicates that the preparation method of the present invention, which involves covalently linking any one or at least two of the specific fragrance substances, namely eugenol, guaiacol, or maltol, to the pulp fibers, can have a positive impact on the tear resistance of the paper. Furthermore, the data from Examples 1-3 and Example 6 show that the grafting effect of maltol is relatively better, the grafting effect of eugenol is second best, and the co-grafting effect of maltol and eugenol is the best.

[0112] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0113] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0114] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for preparing a fragrance-loaded paper-based material, characterized in that, The preparation method includes the following steps: (1) Epoxidation modification of papermaking plant pulp; (2) The epoxidized plant pulp is mixed with phenolic aroma substances and a catalyst and subjected to a thermal reaction to obtain phenolic aroma substances grafted plant pulp; the phenolic aroma substances are selected from any one or at least a combination of two of eugenol, guaiacol or maltol. (3) Papermaking is carried out using phenolic fragrance substances grafted plant pulp as raw material to obtain fragrance-loaded paper base material.

2. The preparation method according to claim 1, characterized in that, The plant pulp in step (1) includes any one or a combination of at least two of the following: broadleaf wood pulp, softwood pulp, straw pulp, bamboo pulp, cotton pulp, or hemp pulp; Preferably, the modifier used in step (1) for epoxidation modification is selected from any one or a combination of at least two of epichlorohydrin, epibromopropane, or dimethyl carbonate.

3. The preparation method according to claim 1 or 2, characterized in that, The epoxidation modification method described in step (1) includes: Papermaking plant pulp is mixed with strong alkali solution and epoxidation modifier, reacted at 50-70℃ for 3-8 hours, and washed to obtain epoxidized plant pulp.

4. The preparation method according to claim 3, characterized in that, The strong alkaline solution includes NaOH solution; Preferably, the ratio of the plant pulp to the strong alkaline solution, based on oven-dry pulp, is 1:(15-35)g / mL; Preferably, the ratio of the plant pulp to the epoxidizing agent, based on oven-dry pulp, is 1:(1-8) g / mL; Preferably, the washing uses ethanol and / or water.

5. The preparation method according to any one of claims 1-4, characterized in that, The mass ratio of the epoxidized plant pulp to the phenolic flavoring substances in step (2) is 1:(1-15); Preferably, the catalyst in step (2) comprises an organic base catalyst; Preferably, the organic base catalyst is selected from pyridine compounds or triethylamine; Preferably, the pyridine compound is selected from any one or a combination of at least two of 4-dimethylaminopyridine, 4-pyrrolidinylpyridine, or 4-tert-butylpyridine; Preferably, the thermal reaction in step (2) is carried out at 50-70°C for 4-8 hours; Preferably, after the thermal reaction in step (2) is completed, cooling, filtration and drying are also performed.

6. The preparation method according to any one of claims 1-5, characterized in that, The phenolic aroma compounds are selected from a combination of eugenol and maltol; Preferably, the mass ratio of eugenol to maltol is 1:(1-4).

7. The preparation method according to any one of claims 1-6, characterized in that, Step (3) The raw materials used in papermaking also include ungrafted plant pulp, which includes any one or a combination of at least two of the following: broadleaf wood pulp, softwood pulp, straw pulp, bamboo pulp, cotton pulp or hemp pulp; Preferably, the raw materials used in papermaking in step (3) also include calcium carbonate, more preferably light calcium carbonate; Preferably, the calcium carbonate accounts for 30-35% of the total weight of the raw materials.

8. The preparation method according to any one of claims 1-7, characterized in that, Step (3) The raw materials used in papermaking also include citrate; Preferably, the citrate comprises potassium citrate and / or sodium citrate.

9. The preparation method according to any one of claims 1-8, characterized in that, Step (3) The papermaking process includes: mixing all the raw materials used in papermaking and then performing a loosening process, followed by papermaking, and then drying the paper sheets obtained after filtration under flattening conditions.

10. The application of the fragrance-loaded paper base material prepared by any one of claims 1-9 in functional paper products.

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