All-bamboo fiber oil-proof paper pulp molded product and preparation method thereof

Abstract

The invention discloses a preparation method of an all-bamboo fiber oil-proof paper pulp molded product. The invention relates to the technical field of paper pulp molded products. The method comprises the following steps: processing a bamboo pulp board raw material to obtain long fiber pulp; 3%-3.5% of an anionic oil-proofing agent, 3% of a waterproof agent and 0.03% of a cationic retention aid are added into the long fiber pulp for pulp preparation, and blended pulp with the pulp concentration being 0.5% is obtained; the preparation method comprises the following steps: blending pulp, carrying out vacuum pulp suction molding on the blended pulp to obtain a paper pulp molding wet blank with the water content of 70-80%, carrying out hot pressing treatment on the wet blank to obtain a semi-finished product with the dryness of more than 90%, and trimming to obtain the full-bamboo fiber oil-proof paper pulp molding product. The oil-proof performance of the product is improved by screening out impurity cells and adding the cationic retention aid.

Description

Technical Field

[0001] The invention relates to the technical field of pulp molded products, in particular to an all-bamboo fiber oil-proof pulp molded product and a preparation method thereof. Background Art

[0002] Pulp molding products are three-dimensional pulp products that use plant fiber pulp (wood, bamboo, reed, grass, etc.) or recycled pulp from waste paper products as the base material, add professional processes and additives, and are vacuum-adsorbed on a special molding mold (also called a water mold or a mesh mold) to form a type of three-dimensional pulp product. Although my country's pulp molding industry started relatively late, it has developed and changed rapidly. In terms of product types, it has evolved from simple low-end products such as egg trays and fruit trays to exquisite industrial and food packaging; in terms of process technology, it has evolved from simple recycling of waste paper to high-end disposable tableware products, which can meet the requirements of waterproof and oil-proof, safe, non-toxic, tasteless, and easy to use. Therefore, my country has reached the world's highest level in terms of certain performance indicators of pulp molding production processes and production equipment. In addition, the production process of pulp molding products does not produce other wastes. After the products are consumed, they can also be easily recycled, and the recycling cost is low. The non-recycled parts can also degrade by themselves, so they are truly "green and environmentally friendly materials."

[0003] However, existing research shows that bamboo fiber pulp molding still has many problems in terms of performance. Bamboo fiber has a high content of miscellaneous cells, including thin-walled cells, epidermal cells and ducts, which will have an adverse effect on the physical properties of paper products, resulting in insufficient strength of the final product. Specifically, the bursting index, tear index and tensile strength of bamboo fiber pulp molded products are low, which limits its promotion in applications requiring high strength. In addition, bamboo fiber has poor hydrophobicity, resulting in poor waterproof and oil-proof properties, and the amount of additives needs to be increased, thereby increasing production costs and reducing the market competitiveness of products. Although bamboo fiber has great potential in the field of pulp molding, its problems such as high miscellaneous cell content, insufficient strength, and poor waterproof and oil-proof properties need to be solved. Summary of the invention

[0004] The object of the present invention is to provide a full bamboo fiber oil-proof pulp molding product and a preparation method thereof in view of the above-mentioned deficiencies in the prior art.

[0005] The method for preparing a full bamboo fiber oil-proof pulp molding product of the present invention comprises the following steps: processing a bamboo pulp board raw material to obtain a long fiber pulp;

[0006] The long fiber pulp is added with 3% to 3.5% of anionic oil repellent, 3% of waterproofing agent, and 0.03% of cationic retention aid to prepare a prepared pulp with a pulp concentration of 0.5%;

[0007] The prepared slurry is vacuum-formed to obtain a pulp molding wet embryo with a moisture content of 70% to 80%. The wet embryo is hot-pressed to obtain a semi-finished product with a dryness greater than 90%. After trimming, a full bamboo fiber oil-proof pulp molding product is obtained.

[0008] Furthermore, the cationic retention aid is one or more of cationic polyacrylamide and cationic polydimethyldiallylammonium chloride.

[0009] Furthermore, the waterproofing agent is an alkyl ketene dimer.

[0010] Furthermore, the vacuum suction time is 15s, and the vacuum degree is 0.06Mpa.

[0011] Further, the wet blank is transferred to a hot pressing mold for hot pressing treatment. The upper mold temperature of the hot pressing treatment is 160° C., the lower mold temperature is 170° C., and the time is controlled at 60 seconds.

[0012] Furthermore, the specific operation of processing the bamboo pulp board raw material to obtain long fiber pulp is as follows:

[0013] Soak the bamboo pulp board for more than 4 hours;

[0014] The soaked pulp board is sent to the Valley pulping machine for decomposition to obtain a wet pulp of a certain concentration;

[0015] The obtained wet slurry is then prepared into a slurry with a concentration of 0.2% to 0.3%;

[0016] Screening the obtained slurry through a sieve;

[0017] The sieved long fibers are prepared into a certain mass concentration and refined by a PFI refiner to cause the fiber cell walls to become fluffy, torn, and fibrillated, thereby obtaining long fiber pulp.

[0018] Furthermore, the slurry was screened through a 14-mesh sieve.

[0019] An all-bamboo fiber oil-proof pulp molding product prepared by the above-mentioned preparation method.

[0020] The present invention improves the oil-proof performance of the product by screening out the foreign cells and adding a cationic retention aid. With 100% pure bamboo pulp as the raw material, the foreign cells in the bamboo pulp are screened and removed by a suitable method, and the purity of the pulp fiber will be greatly improved. Screening out some foreign cells and short fibers, retaining long fibers, and eliminating the influence of foreign cells and short fibers on the oil-proof performance of the pure bamboo fiber pulp molded product from the source can not only improve the oil-proof grade of the product, but also make the combination between the fibers tighter, thereby enhancing the strength and durability of the product, reducing the use of additives, thereby reducing production costs, and improving the economic benefits of the product.

[0021] In order to ensure that the oil repellent and the water repellent are effectively attached to the fiber, the present invention adds a proper amount of cationic retention aid in the system, bridges the fiber and the negatively charged oil repellent through the positively charged cationic aid (for example, CPAM, PDADMAC, etc.), improves the attachment of the oil repellent to the fiber surface, reduces the loss of the oil repellent, and can not only reduce the consumption of medicines, but also further improve the oil repellent level of bamboo fiber products, improve the quality, and reduce the production cost.

[0022] In actual factory production, due to the high content of foreign cells in bamboo pulp, the amount of oil-proofing agent used in pulp molding is increased, which increases the cost. The present invention proposes for the first time to screen out some foreign cells by fiber classification and add an appropriate amount of cationic retention aid (such as CPAM, PDADMAC, etc.) to the bamboo pulp after fiber classification, so that the oil-proofing agent can be more effectively attached to the fiber. The combination of the two methods can reduce the amount of oil-proofing agent used and reduce costs.

[0023] The foreign cells in bamboo pulp are the main factors affecting the strength of pulp molded products produced from bamboo pulp. The more foreign cells there are in bamboo pulp, the higher the beating degree of bamboo pulp, and the worse the water filtration performance. Under the same beating degree conditions, the higher the foreign cell content, the lower the burst index, tear index, tensile strength, elongation at break and folding endurance of bamboo pulp. The present invention proposes for the first time a method of screening out some foreign cells by fiber classification to increase the strength of bamboo pulp and improve product quality.

[0024] The present invention uses 100% bamboo fiber as the raw material for pulp molding, replacing wood with bamboo, which is of great significance to the protection of the environment and forests, and fully utilizes other fast-growing non-wood plant fiber resources. The recycling cost is low, and the unrecycled part can also degrade by itself, so it is a truly "green environmentally friendly material". BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an optical microscope image of short fibers and miscellaneous cells;

[0026] Figure 2 This is an optical microscope image of long fibers;

[0027] Figure 3 This is a statistical diagram of fiber distribution before screening;

[0028] Figure 4 This is a statistical diagram of fiber distribution after screening. DETAILED DESCRIPTION

[0029] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0030] Example 1

[0031] The experimental steps are as follows:

[0032] (1) Soak the bamboo pulp board for more than 4 hours.

[0033] (2) The pulp sheet soaked in step (1) is sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%.

[0034] (3) The wet slurry obtained in step (2) is prepared into a slurry with a concentration of 0.2% to 0.3%.

[0035] (4) The slurry obtained in step (3) is screened through a 14-mesh screen, and the process is repeated twice. The slurry on the screen contains long fiber pulp, and the slurry below the screen contains miscellaneous cells and short fiber pulp. Figure 1 to Figure 4 The beating degrees were measured respectively and the results are shown in Table 1.

[0036] (5) The sieved long fibers are prepared into a mass concentration of 10 wt %, and are refined by a PFI refiner to cause the fiber cell walls to become fluffy, torn, and fibrillated, thereby obtaining bamboo fibers with a beating degree of 35° SR.

[0037] (6) The bamboo fibers after pulping were tested for strength index. The results are shown in Table 3.

[0038] (7) Use deionized water to dilute the reagent for use, the dilution ratio is 1:20. Add 3% oil repellent, 3% water repellent, and 0.03% retention aid to the long fiber pulp after beating, adjust the pulp concentration to 0.5% with water, obtain bamboo fiber pulp for pulp molding, and measure the oil repellency value. The results are shown in Table 2.

[0039] (8) A pulp molding machine is used to obtain a pulp molding wet blank with a moisture content of 70% to 80% by vacuum suction molding (slurry suction time 15 seconds, vacuum degree 0.06 MPa); the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to 160°C for the upper mold temperature and 170°C for the lower mold temperature, and the time is controlled at 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a pure bamboo fiber pulp molding product.

[0040] from Figure 1-Figure 4 It can be seen that fiber classification can reduce the content of foreign cells and short fibers, and the proportion of long fibers after screening is higher and the average length is longer.

[0041] Example 2

[0042] The experimental steps are as follows:

[0043] (1) Soak the bamboo pulp board raw materials for more than 4 hours.

[0044] (2) The pulp sheet soaked in step (1) is sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%.

[0045] (3) The wet slurry obtained in step (2) is prepared into a slurry with a concentration of 0.2% to 0.3%.

[0046] (4) The slurry obtained in step (3) is sieved through a 14-mesh sieve, and the process is repeated twice. The sieve contains long-fiber slurry, and the sieve contains miscellaneous cells and short-fiber slurry.

[0047] (5) The sieved long fibers are prepared into a mass concentration of 10 wt %, and are refined by a PFI refiner to cause the fiber cell walls to become fluffy, torn, and fibrillated, thereby obtaining bamboo fibers with a beating degree of 35° SR.

[0048] (6) Use deionized water to dilute the reagents for use, with a dilution ratio of 1:20. Add 3.5% oil repellent, 3% water repellent, and 0.03% retention aid to the long fiber pulp after beating, and adjust the pulp concentration to 0.5% with water to obtain bamboo fiber pulp for pulp molding, and measure the oil repellency value. The results are shown in Table 2. Perform strength index testing, and the results are shown in Table 3.

[0049] (7) The prepared slurry is formed by a pulp molding machine using vacuum slurry suction molding, the slurry suction time is 15 seconds, the vacuum degree is 0.06 MPa, and a pulp molding wet blank with a moisture content of 70% to 80% is obtained; the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to an upper mold temperature of 160° C. and a lower mold temperature of 170° C., and the time is controlled to be 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a 100% bamboo pulp pulp molding product.

[0050] Comparative Example 1

[0051] The experimental steps are as follows:

[0052] (1) Soak the bamboo pulp board raw materials for more than 4 hours.

[0053] (2) The pulp sheet soaked in step (1) was sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%. The beating degree was measured, and the results are shown in Table 1.

[0054] (3) The strength index of bamboo fiber was tested. The results are shown in Table 3.

[0055] (4) The reagents were diluted with deionized water at a dilution ratio of 1:20. 3% oil repellent and 3% water repellent were added to the pulped bamboo fibers, and the pulp concentration was adjusted to 0.5% with water to obtain bamboo fiber pulp for pulp molding, and the oil repellency value was measured. The results are shown in Table 2.

[0056] (5) The prepared slurry is formed by a pulp molding machine, using vacuum slurry suction molding, the slurry suction time is 15 seconds, the vacuum degree is 0.06 MPa, and a pulp molding wet blank with a moisture content of 70% to 80% is obtained; the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to an upper mold temperature of 160° C. and a lower mold temperature of 170° C., and the time is controlled at 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a 100% bamboo pulp pulp molding product.

[0057] Comparative Example 2

[0058] The experimental steps are as follows:

[0059] (1) Soak the bamboo pulp board raw materials for more than 4 hours.

[0060] (2) The pulp sheet soaked in step (1) is sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%.

[0061] (3) The bamboo fiber was prepared into a mass concentration of 10 wt%, and was refined by a PFI refiner to cause the fiber cell wall to become fluffy, torn, and fibrillated, thereby obtaining bamboo fiber with a beating degree of 35° SR. The strength index was tested, and the results are shown in Table 3.

[0062] (4) The reagents were diluted with deionized water at a dilution ratio of 1:20. 3% oil repellent and 3% water repellent were added to the pulped bamboo fibers to obtain bamboo fiber slurry for pulp molding. The oil repellency value was measured. The results are shown in Table 2.

[0063] (5) The prepared slurry is formed by a pulp molding machine, using vacuum slurry suction molding, the slurry suction time is 15 seconds, the vacuum degree is 0.06 MPa, and a pulp molding wet blank with a moisture content of 70% to 80% is obtained; the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to an upper mold temperature of 160° C. and a lower mold temperature of 170° C., and the time is controlled at 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a 100% bamboo pulp pulp molding product.

[0064] Comparative Example 3

[0065] The experimental steps are as follows:

[0066] (1) Soak the bamboo pulp board raw materials for more than 4 hours.

[0067] (2) The pulp sheet soaked in step (1) is sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%.

[0068] (3) The bamboo fiber is prepared into a mass concentration of 10 wt %, and is refined by a PFI refiner to cause the fiber cell wall to become fluffy, torn, and fibrillated, thereby obtaining bamboo fiber with a beating degree of 35° SR.

[0069] (4) The reagent was diluted with deionized water at a dilution ratio of 1:20. 3.5% oil repellent and 3% water repellent were added to the pulped bamboo fiber, and the oil repellency value was measured. The results are shown in Table 2.

[0070] (5) The prepared slurry is formed by a pulp molding machine, using vacuum slurry suction molding, the slurry suction time is 15 seconds, the vacuum degree is 0.06 MPa, and a pulp molding wet blank with a moisture content of 70% to 80% is obtained; the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to an upper mold temperature of 160° C. and a lower mold temperature of 170° C., and the time is controlled at 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a 100% bamboo pulp pulp molding product.

[0071] Comparative Example 4

[0072] The experimental steps are as follows:

[0073] (1) Soak the bamboo pulp board raw materials for more than 4 hours.

[0074] (2) The pulp sheet soaked in step (1) is sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%.

[0075] (3) The wet slurry obtained in step (2) is prepared into a slurry with a concentration of 0.2% to 0.3%.

[0076] (4) The slurry obtained in step (3) is sieved through a 14-mesh sieve, and the process is repeated twice. The sieve contains long-fiber slurry, and the sieve contains miscellaneous cells and short-fiber slurry.

[0077] (5) The sieved long fibers are prepared into a mass concentration of 10 wt %, and are refined by a PFI refiner to cause the fiber cell walls to become fluffy, torn, and fibrillated, thereby obtaining bamboo fibers with a beating degree of 35° SR.

[0078] (6) Use deionized water to dilute the reagent for use, the dilution ratio is 1:20. Add 3% oil repellent and 3% waterproofing agent to the long fiber pulp after beating, adjust the pulp concentration to 0.5% with water, obtain bamboo fiber pulp for pulp molding, and measure the oil repellency value. The results are shown in Table 2.

[0079] (7) The prepared slurry is formed by a pulp molding machine using vacuum slurry suction molding, the slurry suction time is 15 seconds, the vacuum degree is 0.06 MPa, and a pulp molding wet blank with a moisture content of 70% to 80% is obtained; the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to an upper mold temperature of 160° C. and a lower mold temperature of 170° C., and the time is controlled to be 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a 100% bamboo pulp pulp molding product.

[0080] Comparative Example 5

[0081] The experimental steps are as follows:

[0082] (1) Soak the bamboo pulp board raw materials for more than 4 hours.

[0083] (2) The pulp sheet soaked in step (1) is sent to a Wally pulper for decomposition to obtain a wet pulp with a concentration of 1.57%.

[0084] (3) The wet slurry obtained in step (2) is prepared into a slurry with a concentration of 0.2% to 0.3%.

[0085] (4) The slurry obtained in step (3) is sieved through a 14-mesh sieve, and the process is repeated twice. The sieve contains long-fiber slurry, and the sieve contains miscellaneous cells and short-fiber slurry.

[0086] (5) The sieved long fibers are prepared into a mass concentration of 10 wt %, and are refined by a PFI refiner to cause the fiber cell walls to become fluffy, torn, and fibrillated, thereby obtaining bamboo fibers with a beating degree of 35° SR.

[0087] (6) Use deionized water to dilute the reagent for use, the dilution ratio is 1:20. Add 3.5% oil repellent and 3% waterproofing agent to the long fiber pulp after beating, adjust the pulp concentration to 0.5% with water, obtain bamboo fiber pulp for pulp molding, and measure the oil repellency value. The results are shown in Table 2. Perform strength index testing, the results are shown in Table 3.

[0088] (7) The prepared slurry is formed by a pulp molding machine using vacuum slurry suction molding, the slurry suction time is 15 seconds, the vacuum degree is 0.06 MPa, and a pulp molding wet blank with a moisture content of 70% to 80% is obtained; the wet blank is transferred to a hot pressing mold for heat treatment, the hot pressing temperature is set to an upper mold temperature of 160° C. and a lower mold temperature of 170° C., and the time is controlled to be 60 seconds to obtain a semi-finished product with a dryness greater than 90%. After the dried semi-finished product is cooled, it is trimmed by a paper mold trimming machine to finally obtain a 100% bamboo pulp pulp molding product.

[0089] Table 1 Beating degree measurement results

[0090]

[0091] Table 2 Sample oil resistance test results

[0092] Oil resistance Example 1 5 Example 2 7 Comparative Example 1 0 Comparative Example 2 1 Comparative Example 3 4 Comparative Example 4 4 Comparative Example 5 6

[0093] Table 3 Sample strength index test results

[0094]

[0095] It can be seen from Table 1 that the beating degree of the screened short fiber pulp and the impurity cells is very high and the water filterability is poor. The beating degree after the impurity cells are screened out is lower than the beating degree before the impurity cells are screened out, which proves that screening out some impurity cells is beneficial to improving the water filterability of bamboo pulp.

[0096] It can be seen from Table 2 that when the oil-proof agent content is 3% and 3.5%, the oil-proof value of the sample after screening out the foreign cells is greater than the oil-proof value of the sample before screening out the foreign cells, which proves that screening out some foreign cells can improve the oil-proof value of bamboo pulp; after adding the retention agent, the oil-proof grade of the sample is improved, which proves that the retention agent can make the oil-proof agent and the water-proof agent effectively adhere to the fiber and improve the oil-proof performance of the product.

[0097] The combination of pulping, screening out foreign cells and adding retention aids can improve the oil resistance level by 5 levels under the condition of 3% oil resistance agent, so the amount of oil resistance agent can be significantly reduced in actual production.

[0098] It can be seen from Table 3 that after screening out some of the foreign cells, the bursting index, tearing index and tensile strength of the paper are higher than the corresponding values ​​of bamboo pulp before screening out the foreign cells, and are significantly improved compared with the untreated bamboo pulp, proving that screening out some of the foreign cells can improve the physical properties of bamboo pulp. And it can be seen from Comparative Examples 2 and 5 that after adding the retention aid, the physical properties of the samples are also improved.

[0099] For matters not mentioned above, the prior art applies.

[0100] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an all-bamboo fiber oil-proof pulp molding product, characterized in that: The method comprises the following steps: processing bamboo pulp board raw materials to obtain long fiber pulp; The long fiber pulp is added with 3% to 3.5% of anionic oil repellent, 3% of waterproofing agent, and 0.03% of cationic retention aid to prepare a prepared pulp with a pulp concentration of 0.5%; The prepared slurry is vacuum-formed to obtain a pulp molding wet embryo with a moisture content of 70% to 80%. The wet embryo is hot-pressed to obtain a semi-finished product with a dryness greater than 90%. After trimming, a full bamboo fiber oil-proof pulp molding product is obtained.

2. The preparation method according to claim 1, characterized in that: The cationic retention aid is one or more of cationic polyacrylamide and cationic polydimethyldiallylammonium chloride.

3. The preparation method according to claim 1, characterized in that: The waterproofing agent is an alkyl ketene dimer.

4. The preparation method according to claim 1, characterized in that: The vacuum suction time is 15s and the vacuum degree is 0.06Mpa.

5. The preparation method according to claim 1, characterized in that: The wet blank was transferred to a hot pressing mold for hot pressing treatment. The upper mold temperature was 160°C, the lower mold temperature was 170°C, and the time was controlled at 60s.

6. The preparation method according to claim 1, characterized in that: The specific operation of processing bamboo pulp board raw materials to obtain long fiber pulp is as follows: Soak the bamboo pulp board for more than 4 hours; The soaked pulp board is sent to the Valley pulping machine for decomposition to obtain a wet pulp of a certain concentration; The obtained wet slurry is then prepared into a slurry with a concentration of 0.2% to 0.3%; Screening the obtained slurry through a sieve; The sieved long fibers are prepared into a certain mass concentration and refined by a PFI refiner to cause the fiber cell walls to become fluffy, torn, and fibrillated, thereby obtaining long fiber pulp.

7. The preparation method according to claim 6, characterized in that: The slurry was sieved through a 14-mesh sieve.

8. An all-bamboo fiber oil-proof pulp molding product prepared by the preparation method according to any one of claims 1 to 7.

Images