Preparation method of dry-method paper-based buffer material and dry-method paper-based buffer material

Abstract

The invention relates to the technical field of paper-based materials, and discloses a preparation method of a dry-method paper-based buffer material and the dry-method paper-based buffer material. According to the invention, a soft polyurethane foam material is used as a binding material, the buffering performance is increased by means of the foaming capacity of the soft polyurethane foam material, and the effect of binding fibers is also achieved; in addition, the hot-melt fibers can also play a role in bonding and enhance the strength of the material; the cellulose nanofibers can ensure the high strength of the polyurethane material, so that each layer of material has similar strength, and the overall strength of the material is further ensured. The paper-based buffer material prepared by the method has obvious advantages in the aspects of strength and buffer performance, and can protect articles from being influenced by external impact force. According to the invention, a dry forming process is adopted, and compared with a traditional wet preparation process, water resource consumption and wastewater discharge are reduced; only a small amount of adhesive is used, so that the environmental protection pressure is effectively reduced, and the development of a more environment-friendly and efficient packaging solution is promoted.

Description

Technical Field

[0001] The invention relates to a preparation method of a dry-process paper-based buffer material and the dry-process paper-based buffer material, belonging to the technical field of paper-based materials. Background Art

[0002] In the modern packaging industry, cushioning materials play a vital role, especially in protecting fragile items from impact, vibration and pressure damage that may be encountered during transportation and handling. As a new type of environmentally friendly and efficient cushioning material, paper-based cushioning materials have received widespread attention and development in recent years. Although traditional cushioning materials such as polyethylene foam (EPE) and polystyrene foam (EPS) have good cushioning properties, they have disadvantages such as being difficult to degrade and difficult to recycle, which puts a certain amount of pressure on the environment. In contrast, paper-based cushioning materials use renewable resources as raw materials, which can not only effectively reduce environmental pollution, but also conform to the development concept of circular economy.

[0003] Dry forming technology is a forming process relative to the traditional wet process. It uses air instead of water as a medium for dispersing and transporting fibers. It mainly processes paper fibers or other fiber materials into cushioning products with a certain shape and structure through physical methods (only a small amount of adhesive is used in the process). This manufacturing process does not require the use of a large amount of water, reduces the consumption of water resources and wastewater discharge, and thus reduces the impact on the environment. At the same time, it also reduces the huge energy consumption required for the drying process in previous wet manufacturing, saving a lot of energy consumption. In addition, because the paper-based material has good air permeability, this makes the dry paper-based cushioning material show unique advantages in some application scenarios that require maintaining a certain humidity or ventilation conditions. With the continuous improvement of society's awareness of environmental protection and the promotion of technological progress, dry paper-based cushioning materials have gradually become an important development direction in the future packaging field due to their green and sustainable characteristics. Summary of the invention

[0004] The technical problem that the present invention aims to solve is: in view of the high energy consumption of the wet molding process, a paper-based cushioning material with excellent elasticity and strength properties is prepared by using dry molding technology; the technology has the characteristics of low energy consumption, simple steps, and easy operation. The present invention also provides a method for preparing a dry paper-based cushioning material, which uses soft polyurethane foam material, cellulose nanofibers and hot-melt fibers to prepare a paper-based material with excellent strength and cushioning effect, while ensuring the simplicity and controllability of operation to meet the needs of different application scenarios.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for preparing a dry paper-based cushioning material, comprising the following steps:

[0007] Step 1), take the pulping board, divide it into small pieces, put it into a pulverizer to break it into pulp fibers, and filter out fine fiber particles;

[0008] Step 2), mixing the pulp fibers and the hot-melt fibers to obtain mixed fibers;

[0009] Step 3), preparing a polyurethane foam material, and spraying a layer of the polyurethane foam material evenly on the bottom of the mold;

[0010] Step 4), quickly and evenly spread the mixed fibers in step 2) on the surface of the polyurethane foam material to obtain a mixed fiber layer;

[0011] Step 5), quickly spray a layer of polyurethane foam material on the surface of the mixed fiber layer, and press it with a cover plate to make it fully bonded;

[0012] Step 6) Repeat the above steps until the thickness of the entire material reaches the target requirement;

[0013] Step 7), placing the prepared mold material in an oven for heating treatment, on the one hand, the polyurethane foam material is foamed and matured to play a bonding and cushioning effect; on the other hand, the hot-melt fiber is partially melted to play a further bonding effect, and then cooled to obtain the final product.

[0014] Preferably, in step 1), the pulp board comprises one or both of coniferous wood pulp board and hardwood wood pulp board. When both are used, the weight ratio of the coniferous wood pulp board to the hardwood pulp board is 3:7 to 5:5.

[0015] Preferably, in the step 1), the shredded pulp board is different from the whole pulp board, and is obtained by decomposing the whole pulp board.

[0016] Preferably, in step 1), the time for the pulverizer to mechanically pulverize the pulping plate is controlled between 8 and 30 seconds.

[0017] Preferably, in the step 2), the mixing ratio of the hot-melt fiber to the pulp fiber is 1:9 to 2:8, and the hot-melt fiber includes one of PE fiber and ES fiber.

[0018] Preferably, in the step 3), the preparation method of the special soft polyurethane foam material comprises: adding polyether polyol 2070A, polyether polyol EP-330N, polymer polyol POP3682, foam stabilizer B8002, triethylenediamine, dibutyltin dilaurate and deionized water in an aerosol can in sequence according to a precise ratio, then adding weighed diphenylmethane diisocyanate W8019 raw material and cellulose nanofibers, then filling with gas, closing the can mouth, shaking the can body sufficiently, and connecting the spray gun head for use.

[0019] Preferably, in step 3), cellulose nanofibers are added to the special soft polyurethane foam material to enhance the strength of the polyurethane foam layer material, and by adjusting the size and addition ratio of the cellulose nanofibers, characteristics similar to the mechanical properties of the upper and lower fiber layers are achieved.

[0020] More preferably, the cellulose nanofibers have a diameter of ≤100 nm and a length of 0.5 to 20 μm, and the ratio of the cellulose nanofibers to the polyurethane foam material is 0.5:9.5 to 3:7.

[0021] Preferably, in step 4), the ratio of the polyurethane foam material to the mixed fiber is controlled between 1.2:8.8 and 1.6:8.4.

[0022] Preferably, in step 4), the thickness of each fiber layer is controlled to be about 5 to 8 mm.

[0023] Preferably, in step 7), the oven temperature is controlled between 135 and 140° C., and the drying time is controlled between 20 and 45 minutes.

[0024] In a second aspect, the present invention also provides a paper-based cushioning material prepared by the above-mentioned preparation method.

[0025] Preferably, the paper-based buffer material comprises 7 to 8 parts by weight of pulp fiber, 0.8 to 1.8 parts of hot-melt fiber, and 1.2 to 1.6 parts of polyurethane foam material.

[0026] Preferably, the pulp fiber is a mixture of coniferous wood pulp and hardwood wood pulp; the weight ratio thereof is 3:7 to 5:5.

[0027] Preferably, the hot-melt fibers include PE fibers and ES fibers.

[0028] The present invention provides a paper-based cushioning material and a preparation method thereof. The preparation steps of the paper-based cushioning material are simple and easy to operate. The dry paper-based cushioning material provided by the present invention can provide excellent compression resistance and shock resistance and cushioning performance, and protect items from external impact forces. It has the characteristics of being recyclable and biodegradable, and conforms to the development trend of modern green packaging. The present invention adopts a dry molding process to prepare paper-based cushioning materials. Compared with the traditional wet preparation process, the production process does not use water, which reduces water resource consumption and wastewater discharge, and only uses a small amount of adhesive, which effectively reduces environmental pressure and promotes the development of more environmentally friendly and efficient packaging solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention provides a flow chart of a method for preparing a paper-based cushioning material. DETAILED DESCRIPTION

[0030] In order to make the present invention more clearly understood, preferred embodiments are described in detail as follows.

[0031] Preparation Example

[0032] A special soft polyurethane foam material comprising the following components by weight:

[0033] Polyether polyol 2070A (Dow Chemical Company) 40 parts;

[0034] Polyether polyol EP-330N (Shandong Bluestar Dongda Chemical Co., Ltd.) 50 parts;

[0035] Polymer polyol POP3682 (Shandong Bluestar Dongda Chemical Co., Ltd.) 10 parts;

[0036] Foam stabilizer B8002 (Evonik Degussa (China) Investment Co., Ltd.) 1 part;

[0037] Triethylenediamine (Shandong Binli New Materials Co., Ltd.) 0.3 parts;

[0038] Dibutyltin dilaurate (Air Products & Chemicals, Inc., USA) 0.1 part;

[0039] 3 parts of deionized water;

[0040] 70 parts of diphenylmethane diisocyanate W8019 (Wanhua Chemical Group Co., Ltd.);

[0041] 10 parts of cellulose nanofibers (diameter ≤ 100 nm, length between 0.5 and 20 μm).

[0042] The preparation method is as follows: polyether polyol 2070A, polyether polyol EP-330N, polymer polyol POP3682, foam stabilizer B8002, triethylenediamine, dibutyltin dilaurate and deionized water are added into an aerosol can in precise proportions, then weighed diphenylmethane diisocyanate W8019 raw materials and cellulose nanofibers are added, and then gas (DME and propane and butane) is filled, the can mouth is closed, the can body is fully shaken, and a spray gun head is connected for use.

[0043] Example 1

[0044] A paper-based cushioning material comprises the following components by weight: 7.92 parts of pulp fiber, 0.88 parts of hot-melt fiber and 1.2 parts of polyurethane foam material.

[0045] The method for preparing the paper-based cushioning material comprises the following steps:

[0046] (1) preparing two types of pulp boards, namely, coniferous wood pulp board and hardwood wood pulp board, dividing them into small pieces of 0.5 cm×0.5 cm and putting them into a crusher, controlling the crushing time of the crusher to be 11 seconds, crushing them into pulp fibers, filtering out fine fiber particles, repeating this step to obtain a sufficient amount of pulp fibers, and then mixing the two types of pulp fibers evenly in a ratio of 4:6;

[0047] (2) taking 7.92 parts by weight of the mixed pulp fibers and 0.88 parts by weight of PE fibers, and mixing them uniformly to obtain mixed fibers;

[0048] (3) The total weight of the polyurethane foam material used in this preparation (preparation method described in the preparation example) is 1.2 parts. Use a spray gun to evenly spray a layer of the prepared special soft polyurethane foam material on the bottom of the mold, paying attention to the amount of polyurethane foam material used each time;

[0049] (4) quickly and evenly spreading the mixed fiber on the surface of the polyurethane foam material to obtain a mixed fiber layer, and controlling the thickness of the mixed fiber layer to be about 6 mm;

[0050] (5) Quickly spray a layer of polyurethane foam material on the surface of the mixed fiber layer. At this time, you should also pay attention to controlling the amount of polyurethane foam material, and then use a cover plate to press it appropriately to make it fully bonded;

[0051] (6) Repeat the above steps until the thickness of the entire material reaches the target requirement;

[0052] (7) The prepared mold material is placed in an oven for heating treatment. The oven temperature is set to 140°C and the heating time is 35 minutes. The heating causes the polyurethane foam material to foam and mature, thereby playing a bonding and cushioning role. On the other hand, the PE fiber is partially melted to play a bonding role. The melted PE fiber makes the internal bonding of the pulp fiber more complete. The mold material is then cooled to obtain the final product.

[0053] Example 2

[0054] A paper-based cushioning material comprises the following components by weight: 7.04 parts of pulp fibers, 1.76 parts of hot-melt fibers, and 1.2 parts of polyurethane foam materials.

[0055] The method for preparing the paper-based cushioning material comprises the following steps:

[0056] (1) preparing two types of pulp boards, namely, coniferous wood pulp board and hardwood wood pulp board, dividing them into small pieces of 0.5 cm×0.5 cm and putting them into a crusher, controlling the crushing time of the crusher to be 11 seconds, crushing them into pulp fibers, filtering out fine fiber particles, repeating this step to obtain a sufficient amount of pulp fibers, and then mixing the two types of pulp fibers evenly in a ratio of 4:6;

[0057] (2) taking 7.04 parts by weight of the mixed pulp fibers and 1.76 parts by weight of PE fibers, and mixing them uniformly to obtain mixed fibers;

[0058] (3) The total weight of the polyurethane foam material used in this preparation (preparation method described in the preparation example) is 1.2 parts. Use a spray gun to evenly spray a layer of the prepared special soft polyurethane foam material on the bottom of the mold, paying attention to the amount of polyurethane foam material used each time;

[0059] (4) quickly and evenly spreading the mixed fiber on the surface of the polyurethane foam material to obtain a mixed fiber layer, and controlling the thickness of the mixed fiber layer to be about 7 mm;

[0060] (5) Quickly spray a layer of polyurethane foam material on the surface of the mixed fiber layer. At this time, you should also pay attention to controlling the amount of polyurethane foam material, and then use a cover plate to press it appropriately to make it fully bonded;

[0061] (6) Repeat the above steps until the thickness of the entire material reaches the target requirement;

[0062] (7) The prepared mold material is placed in an oven for heating treatment. The oven temperature is set to 140°C and the heating time is 40 minutes. The heating causes the polyurethane foam material to foam and mature, thereby playing a bonding and cushioning role. On the other hand, the PE fiber is partially melted to play a bonding role. The melted PE fiber makes the internal bonding of the pulp fiber more complete. The mold material is then cooled to obtain the final product.

[0063] Example 3

[0064] A paper-based cushioning material comprises the following components by weight: 7.56 parts of pulp fiber, 0.84 parts of hot-melt fiber and 1.6 parts of polyurethane foam material.

[0065] The method for preparing the paper-based cushioning material comprises the following steps:

[0066] (1) preparing two types of pulp boards, namely, coniferous wood pulp board and hardwood wood pulp board, dividing them into small pieces of 0.5 cm×0.5 cm and putting them into a crusher, controlling the crushing time of the crusher to be 11 seconds, crushing them into pulp fibers, filtering out fine fiber particles, repeating this step to obtain a sufficient amount of pulp fibers, and then mixing the two types of pulp fibers evenly in a ratio of 4:6;

[0067] (2) taking 7.56 parts by weight of the mixed pulp fibers and 0.84 parts by weight of ES fibers, and mixing them uniformly to obtain mixed fibers;

[0068] (3) The total weight of the polyurethane foam material used in this preparation (preparation method described in the preparation example) is 1.6 parts. Use a spray gun to evenly spray a layer of the prepared special soft polyurethane foam material on the bottom of the mold, paying attention to the amount of polyurethane foam material used each time;

[0069] (4) quickly and evenly spreading the mixed fiber on the surface of the polyurethane foam material to obtain a mixed fiber layer, and controlling the thickness of the mixed fiber layer to be about 7 mm;

[0070] (5) Quickly spray a layer of polyurethane foam material on the surface of the mixed fiber layer. At this time, you should also pay attention to controlling the amount of polyurethane foam material, and then use a cover plate to press it appropriately to make it fully bonded;

[0071] (6) Repeat the above steps until the thickness of the entire material reaches the target requirement;

[0072] (7) The prepared mold material is placed in an oven for heating treatment. The oven temperature is set to 135°C and the heating time is 40 minutes. The heating causes the polyurethane foam material to foam and mature, thereby playing a bonding and cushioning role. On the other hand, the ES fiber is partially melted to play a bonding role. The melted ES fiber makes the internal bonding of the pulp fiber more complete. The mold material is then cooled to obtain the final product.

[0073] Comparative Example

[0074] A method for preparing a cushioning packaging material comprises the following steps:

[0075] (1) Weighing 65 parts of corn starch, 55 parts of rice straw (80 mesh), 10 parts of kaolin, and 1.5 parts of glyceryl monostearate by weight, mixing and stirring to obtain a mixture;

[0076] (2) Add the mixture obtained in step (1), 10 parts of polyvinyl alcohol and 1.5 parts of sodium hydroxide to 180 parts of water, stir evenly, add 4 parts of aluminum powder foaming agent, stir evenly and inject into a mold, put the mold into an oven, dry at 135°C for 1.5 hours, cool, and demold to obtain a finished product.

[0077] The performance tests were conducted on the paper-based cushioning materials of Examples 1-3 and the cushioning packaging materials of the comparative example. The results are shown in Table 1 below.

[0078] (1) Compression resilience: The percentage of the volume of the sample to the initial volume after the volume of the obtained cushioning packaging material is compressed by 50% and maintained for 72 hours.

[0079] (2) Impact strength: Test the impact strength in accordance with GB / T 17657-2022.

[0080] Table 1

[0081] name Rebound rate (%) <![CDATA[Impact strength (KJ·m 2 )]]> <![CDATA[Density (kg / m 3 )]]> Example 1 83 6.81 52 Example 2 87 6.93 55 Example 3 84 7.05 59 Comparative Example 82.1 6.58 152

[0082] As can be seen from the table, the three paper-based cushioning materials prepared have good resilience and impact resistance, and their rebound rate and impact strength are better than those of the materials prepared in the comparative example, and their density is significantly better than that of the comparative example, which can be well applied to the field of packaging materials. In addition, the oven heating time required in the preparation process of this method is much lower than that of the comparative example, which greatly reduces the energy consumption demand and can balance the production cost to a certain extent.

[0083] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a dry paper-based cushioning material, characterized in that: The following steps are involved: Step 1), take the pulping board, divide it into small pieces, put it into a pulverizer to break it into pulp fibers, and filter out fine fiber particles; Step 2), mixing the pulp fibers and the hot-melt fibers to obtain mixed fibers; Step 3), preparing a polyurethane foam material, and spraying a layer of the polyurethane foam material evenly on the bottom of the mold; Step 4), quickly and evenly spread the mixed fibers in step 2) on the surface of the polyurethane foam material to obtain a mixed fiber layer; Step 5), quickly spray a layer of polyurethane foam material on the surface of the mixed fiber layer, and press it with a cover plate to make it fully bonded; Step 6) Repeat the above steps until the thickness of the entire material reaches the target requirement; Step 7), placing the prepared mold material in an oven for heating treatment, on the one hand, the polyurethane foam material is foamed and matured to play a bonding and cushioning effect; on the other hand, the hot-melt fiber is partially melted to play a further bonding effect, and then cooled to obtain the final product.

2. The preparation method according to claim 1, characterized in that In the step 1), the pulp board includes one or both of a coniferous wood pulp board and a hardwood wood pulp board. When both are used, the weight ratio of the coniferous wood pulp board to the hardwood wood pulp board is 3:7 to 5:

5.

3. The preparation method according to claim 1, characterized in that: In the step 1), the time for the pulverizer to mechanically pulverize the pulping plate is controlled between 8 and 30 seconds.

4. The preparation method according to claim 1, characterized in that: In the step 2), the mixing ratio of the hot-melt fiber to the pulp fiber is 1:9 to 2:8, and the hot-melt fiber includes one of PE fiber and ES fiber.

5. The preparation method according to claim 1, characterized in that: In the step 3), the preparation method of the polyurethane foam material comprises: adding polyether polyol 2070A, polyether polyol EP-330N, polymer polyol POP3682, foam stabilizer B8002, triethylenediamine, dibutyltin dilaurate and deionized water in an aerosol can in sequence according to a precise ratio, then adding weighed diphenylmethane diisocyanate W8019 raw material and cellulose nanofibers, then filling with gas, closing the can mouth, shaking the can body sufficiently, and connecting the spray gun head for use.

6. The preparation method according to claim 5, characterized in that: In the step 3), the cellulose nanofibers preferably have a diameter of ≤100 nm and a length of 0.5 to 20 μm, and the ratio of the cellulose nanofibers to the polyurethane foam material is 0.5:9.5 to 3:

7.

7. The preparation method according to claim 1, characterized in that: In the step 4), the ratio of the polyurethane foam material to the mixed fiber is controlled between 1.2:8.8 and 1.6:8.

4.

8. The preparation method according to claim 1, characterized in that: In the step 4), the thickness of each fiber layer is controlled to be about 5 to 8 mm.

9. The preparation method according to claim 1, characterized in that: In the step 7), the oven temperature is controlled between 135 and 140° C., and the drying time is controlled between 20 and 45 minutes.

10. A dry paper-based cushioning material, characterized in that: The method is prepared according to any one of claims 1 to 9.

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