Starch substitute as well as preparation method and application thereof

Abstract

The invention discloses a starch substitute, and belongs to the technical field of paper-making industry, and the starch substitute is prepared from the following raw materials in parts by weight: 20-70 parts of yellow ginger starch, 10-30 parts of coconut shell fiber powder, 1-3 parts of a thickening agent and 1-3 parts of a reinforcing agent. The cardboard paper surface sizing starch substitute is all from byproducts or wastes of natural plant processing, has excellent environmental protection property and low cost, and can greatly replace the original surface sizing starch. And on the basis of ensuring the surface sizing effect and the finished paper quality, the use amount of the surface sizing collagen starch of a paperboard factory can be greatly reduced, and the production cost is reduced. And the sizing effect is good, the ring crush index, the water resistance and other quality indexes of the box board are all improved, and the problem that the box board gets damp in summer can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking, and more particularly to a starch substitute and a preparation method and application thereof. Background Art

[0002] With the development of industrial and agricultural production in my country and the improvement of people's living standards, people pay more and more attention to the quality and form of product packaging. In particular, with the rapid development of the express logistics industry in recent years, the demand for cartons has increased dramatically, and the requirements for the quality of boxboard paper have also become higher and higher. However, most of the raw materials for domestic boxboard paper production use non-wood fiber raw materials or a large amount of recycled waste paper. With the increase in the number of paper recycling, the fiber is repeatedly broken and beaten, resulting in a shortened fiber length, a decay of physical and chemical properties, and a weakening of the affinity of hydrogen bonds between fibers, which causes a significant decrease in the elongation, breaking length and folding endurance of the paper. In order to make up for the defects of the raw materials themselves, the production of boxboard paper and high-strength corrugated paper adopts a surface sizing process with oxidized starch as the main raw material to improve its surface strength, reduce hair loss and powder loss, increase strength and seal the surface to control the penetration of coating materials. Therefore, surface sizing is an indispensable link in the production of board paper.

[0003] However, the amount of starch used in surface sizing can reach 20% to 40% of the paper weight depending on the requirements of board paper and corrugated paper, which is the largest part of the production cost of board paper mills except for pulp. Both corn starch and cassava starch come from food crops, and their prices are increasing, which has caused a serious cost burden for papermaking companies. Therefore, the market urgently needs a high-quality, low-cost substitute for original starch for surface sizing.

[0004] However, several starch substitutes that have appeared so far are not ideal. For example, Chinese patent CN103437245B discloses a surface sizing starch substitute and a preparation process. The patent puts 1500 parts by weight of sodium sulfate and 8-20 parts by weight of surfactant into a reaction tank, under the condition of 100-130°C, the stirring speed is 60-90 revolutions per minute, the reaction is taken out of the tank for 3-4 hours, and the mixture is directly sieved after cooling to room temperature, and 450-550 parts by weight of cationic cassava starch and 3-10 parts by weight of polyacrylamide are added and stirred to prepare the mixture. Chinese patent CN110230232A discloses a starch substitute, including the following raw materials in weight proportions: 50-100 parts of anhydrous sodium sulfate, 4-10 parts of soda ash, 4-10 parts of amylase, 2-5 parts of sodium dodecyl sulfate, 4-10 parts of carboxymethyl fiber and 15-25 parts of wollastonite fiber. The above raw materials are obtained by crushing and mixing. Chinese patent CN111485449A discloses a starch substitute, which comprises the following raw materials by weight: 30-40 parts of anhydrous sodium sulfate, 30-40 parts of rubber powder, and 30-40 parts of iron-free aluminum sulfate. According to the weight ratio of the starch substitute, the anhydrous sodium sulfate and the rubber powder are stirred at high speed for 30-40 minutes, and the iron-free aluminum sulfate is added and stirred to form a finished product.

[0005] Looking at the above starch substitutes, they are basically composed of inorganic salts as the main component and supplemented with a small amount of polymer film-forming agent. Although they have a certain sizing effect, the paper will become brittle and easy to get damp after sizing, and the sizing effect is not ideal. In addition, inorganic salts are easily soluble in water, which increases the burden of water treatment and is not environmentally friendly. In order to overcome the above shortcomings, the present invention proposes a new type of starch substitute for sizing of boxboard surface to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a starch substitute and a preparation method and application thereof, so as to solve the shortcomings of the current starch substitute for boxboard surface sizing. The boxboard surface sizing starch substitute provided by the present invention is derived from by-products or wastes of natural plant processing, has excellent environmental protection, and is low in cost, and can largely replace the original surface sizing starch.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions: The first aspect of the present invention provides a starch substitute. The raw materials for preparing the starch substitute include, by weight, 20 to 70 parts of turmeric starch, 10 to 30 parts of coconut shell fiber powder, 1 to 3 parts of thickener, and 1 to 3 parts of enhancer.

[0008] The main raw material of the starch substitute of the present invention is turmeric starch, which is a byproduct obtained when turmeric is used to produce medicinal saponins. The preparation method is a conventional technical means in the art, which is briefly described as follows: Yellow turmeric is a wild plant unique to my country. However, after it was discovered that it is rich in diosgenin (saponin) that can produce steroid hormone drugs, people began to plant it in large quantities. It has now become the medicinal plant with the highest diosgenin content in my country, with an average diosgenin content of about 2%, and the highest content of a single plant can reach 16%. my country is rich in yellow turmeric resources and is a precious medicinal plant resource in the world. In addition to being used to extract diosgenin, yellow turmeric also contains polysaccharides such as starch, which accounts for 45% of its dry weight, and cellulose, which accounts for 50%.

[0009] like Figure 1 As shown in the figure, the specific preparation method of turmeric saponin and byproduct turmeric starch is as follows: the washed and peeled turmeric is mixed with water in a ratio of 1:1, ground with a pin mill, and then homogenized with a homogenizer, and then the slurry is sieved with a coarse (100 mesh) and a fine (200 mesh) flat sieve to obtain a filtrate and a filter residue, respectively. The filter residue is washed with water, and the filter residue and the filtrate are collected respectively. The filter residue is dried at 40°C under negative pressure to obtain crude turmeric cellulose. The cellulose can be used to extract turmeric saponin, the main product of turmeric, by solvent extraction. The above filtrates are combined, centrifuged through a 150-mesh filter cloth, and the filter cake is washed again. The filter cake is dried and crushed through a 120-mesh sieve to obtain a byproduct turmeric starch. The washing liquid is also combined with the filtrate of the previous step, and a small amount of turmeric saponin is recovered by solvent extraction. The wastewater is discharged after biochemical treatment.

[0010] Furthermore, the particle size of the turmeric starch is 120 meshes.

[0011] In the present invention, the coconut shell fiber powder is obtained by drying the coconut shell after removing the coconut water and coconut flakes, and then crushing and grinding. The preparation method is a conventional technical means in the art, which is briefly described as follows: Coconut is a rich plant resource on Hainan Island. Every year, a large number of coconut fruits mature, and their coconut water is made into beverages, the inner layer of coconut shells is made into coconut flakes, and the outer shells are discarded as waste. The chemical composition of coconut shells is: ash 0.61%, lignin 36.51%, cellulose 53.06%, pentosan 29.27% ​​(total). my country uses more than 1 million tons of coconuts to make coconut milk soft drinks every year, of which coconut shells account for 70-80% by weight. The cortex of coconut shells is hard, and only a small part of coconut shell fibers is used in industrial production, mainly for the production of small carpets, mats, ropes and filter cloths. A large number of coconut shells are mostly disposed of by landfill, which not only wastes land resources, but also fails to make reasonable use of agricultural waste. Countries such as India, Sri Lanka, and the Philippines are major coconut producers and major suppliers of coconut shell fibers. my country also has abundant coconut shell resources, but the application of coconut shell fibers is almost blank. The traditional process of extracting and processing coconut shell fiber makes the fiber uneven in thickness and length, which leads to its limited final use. How to develop a suitable fiber extraction and processing technology is an urgent problem to be solved. The outer layer of coconut shell is a relatively soft long fiber tissue, which is easy to separate by mechanical operation and has a high cellulose content; the second outer layer is harder and easily oxidized to brown.

[0012] In the present invention, the dried coconut shell is first opened and then roughly crushed, and then crushed into 100-mesh fine powder by an ultra-fine grinder, which can be used for surface sizing of paperboard. The cellulose and hemicellulose in the powder can improve the strength and stiffness of the paperboard.

[0013] Furthermore, the particle size of the coconut shell fiber powder is 100 mesh.

[0014] Furthermore, the enhancer is at least one of polyvinyl alcohol, cationic polyacrylamide, and polyethylene oxide; preferably, the molecular weight of the cationic polyacrylamide is 5 million to 8 million.

[0015] Furthermore, the thickener is at least one of sodium alginate, chitosan, sodium polyacrylate, guar gum, and carboxymethyl cellulose.

[0016] The second aspect of the present invention provides a method for preparing the above-mentioned starch substitute, wherein turmeric starch, coconut shell fiber, a thickener and a reinforcing agent are mixed in the above-mentioned weight ratio and added into a grinder, and the mixture is grinded until all of them pass through a 100-mesh sieve to obtain the starch substitute.

[0017] The third aspect of the present invention provides the use of the above-mentioned starch substitute or the starch substitute obtained by the above-mentioned preparation method, wherein the starch substitute is used to replace 20wt% to 50wt% of the original starch in the surface sizing agent of boxboard; preferably, the original starch is selected from at least one of corn starch and cassava starch.

[0018] A fourth aspect of the present invention provides a method for sizing a surface of boxboard, the method comprising: The starch substitute or the starch substitute obtained by the above preparation method is mixed with the original starch in the surface sizing agent of the boxboard to prepare a water slurry with a mass concentration of 6% to 10%, and the temperature is raised to 85°C to 95°C. Ammonium persulfate is added at the same time, and the pH is adjusted to 3.5 to 4.5 with aluminum sulfate. The gelatinization is carried out for 20min to 45min, and the viscosity is controlled to 11.5s to 12.5s (measured with a 4# coating cup). The temperature is then lowered to 70°C to 80°C for insulation, and then the boxboard is put on the machine for surface sizing.

[0019] Furthermore, the amount of the starch substitute is 20wt% to 50wt% of the original starch in the surface sizing agent for boxboard paper; And / or, the amount of ammonium persulfate added is 3wt‰ to 4wt‰ of the total mass of starch; And / or, the native starch in the surface sizing agent for boxboard is selected from at least one of corn starch and cassava starch.

[0020] Beneficial effects: The substitute for starch for surface sizing of boxboard paper of the present invention is derived from byproducts or wastes of natural plant processing, has excellent environmental protection, and is low in cost, and can largely replace the original surface sizing starch. On the basis of ensuring the surface sizing effect and the quality of the finished paper, the amount of original starch for surface sizing of the board paper mill can be greatly reduced, and the production cost can be reduced. The sizing effect is good, and the quality indicators such as the ring crush index and water resistance of the boxboard are improved, and the problem of moisture resorption of the boxboard in summer can be effectively solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0022] Figure 1 This is a process diagram for preparing turmeric saponins and the by-product turmeric starch of this application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the examples and comparative examples of the present invention, all the raw materials used are commercially available unless otherwise specified.

[0025] In the examples and comparative examples of the present invention, cationic polyacrylamide was purchased from Jinan Zhongbei Fine Chemical Co., Ltd., and had a molecular weight of 5 million to 8 million.

[0026] Example 1 This embodiment provides a starch substitute and a preparation method thereof: The raw materials for preparing the starch substitute include, by weight, 36 parts of turmeric starch, 10 parts of coconut shell fiber powder, 2.5 parts of thickener, and 1.5 parts of enhancer: wherein the particle size of the turmeric starch is 120 meshes, and the particle size of the coconut shell fiber powder is 100 meshes; the enhancer is polyethylene oxide; and the thickener is a composition of chitosan and sodium polyacrylate in a mass ratio of 1.0:1.5.

[0027] The preparation method of the starch substitute is as follows: turmeric starch, coconut shell fiber, thickener and enhancer are mixed according to the weight ratio, added into a grinder, and ground until all of them pass through a 100-mesh sieve to obtain the starch substitute.

[0028] This embodiment continues to provide a method for applying sizing to the surface of boxboard: The starch substitute and corn starch (the amount of the starch substitute is 50wt% of the corn starch in the surface sizing agent of the boxboard, that is, the mass ratio of the starch substitute and corn starch is 1:1) are added to a mixing tank to prepare a water slurry with a mass concentration of 8%, stirred evenly, and then pumped into a gelatinization tank, heated to 94°C, and ammonium persulfate (the amount of ammonium persulfate added is 3wt‰ of the total mass of starch) is added for oxidation, and aluminum sulfate is used to adjust the pH to 4.1 (±0.3), gelatinized for 42 minutes, and the viscosity is controlled at 11.5-12.5 seconds (measured with a 4# coating cup), and then cooled to 70-80°C for insulation, pumped into the insulation tank, and then the boxboard is surface sized on the machine. The quality of the boxboard obtained by the original sizing process of the enterprise is compared with that of the enterprise. (This embodiment only changes the starch raw material used originally to the starch raw material described in the present invention, and the other processes remain unchanged. The following embodiments are the same as this) The results are as shown in Table 1: Table 1

[0029] Example 2 This embodiment provides a starch substitute and a preparation method thereof: The raw materials for preparing the starch substitute include, by weight, 29 parts of turmeric starch, 11 parts of coconut shell fiber powder, 2.7 parts of thickener, and 2.3 parts of enhancer: wherein the particle size of the turmeric starch is 120 meshes, and the particle size of the coconut shell fiber powder is 100 meshes; the enhancer is a composition of polyvinyl alcohol and polyethylene oxide in a mass ratio of 1.5:0.8; the thickener is a composition of carboxymethyl cellulose and sodium polyacrylate in a mass ratio of 1.5:1.2.

[0030] The preparation method of the starch substitute is as follows: turmeric starch, coconut shell fiber, thickener and enhancer are mixed according to the weight ratio, added into a grinder, and ground until all of them pass through a 100-mesh sieve to obtain the starch substitute.

[0031] This embodiment continues to provide a method for applying sizing to the surface of boxboard: The starch substitute and corn starch (the amount of the starch substitute is 45wt% of the corn starch in the surface sizing agent of the boxboard, that is, the mass ratio of the starch substitute and corn starch is 45:55) are added to the mixing tank to prepare a water slurry with a mass concentration of 8%, stirred evenly, and then pumped into the gelatinization tank, heated to 92°C, and ammonium persulfate (the amount of ammonium persulfate added is 3wt‰ of the total mass of starch) is added for oxidation, and the pH is adjusted to 4.2 (±0.3) with aluminum sulfate, gelatinized for 38 minutes, and the viscosity is controlled at 11.5-12.5 seconds (measured with a 4# coating cup), and then cooled to 70-80°C for insulation, pumped into the insulation tank, and then the boxboard is surface sized on the machine. The quality of the boxboard obtained by the original sizing process of the enterprise is compared after testing, and the results are as shown in Table 2: Table 2

[0032] Example 3 This embodiment provides a starch substitute and a preparation method thereof: The raw materials for preparing the starch substitute include, by weight, 30 parts of turmeric starch, 15 parts of coconut shell fiber powder, 2.5 parts of thickener, and 2.5 parts of enhancer: wherein the particle size of the turmeric starch is 120 meshes, and the particle size of the coconut shell fiber powder is 100 meshes; the enhancer is a composition of polyvinyl alcohol and cationic polyacrylamide in a mass ratio of 1.5:1.0; and the thickener is a composition of guar gum and sodium polyacrylate in a mass ratio of 1.0:1.5.

[0033] The preparation method of the starch substitute is as follows: turmeric starch, coconut shell fiber, thickener and enhancer are mixed according to the weight ratio, added into a grinder, and ground until all of them pass through a 100-mesh sieve to obtain the starch substitute.

[0034] This embodiment continues to provide a method for applying sizing to the surface of boxboard: The starch substitute and corn starch (the amount of the starch substitute is 50wt% of the corn starch in the surface sizing agent of the boxboard, that is, the mass ratio of the starch substitute and corn starch is 1:1) are added to the mixing tank to prepare a water slurry with a mass concentration of 8%, stirred evenly, and then pumped into the gelatinization tank, heated to 89°C, and ammonium persulfate (the amount of ammonium persulfate added is 3wt‰ of the total mass of starch) is added for oxidation, and the pH is adjusted to 4.2 (±0.3) with aluminum sulfate, gelatinized for 38 minutes, and the viscosity is controlled at 11.5-12.5 seconds (measured with a 4# coating cup), and then cooled to 70-80°C for insulation, pumped into the insulation tank, and then the boxboard is surface sized on the machine. The quality of the boxboard obtained by the original sizing process of the enterprise is compared after testing, and the test results are as shown in Table 3: Table 3

[0035] Example 4 This embodiment provides a starch substitute and a preparation method thereof: The raw materials for preparing the starch substitute include, by weight, 33 parts of turmeric starch, 10 parts of coconut shell fiber powder, 2.2 parts of thickener, and 1.8 parts of enhancer: wherein the particle size of the turmeric starch is 120 meshes, and the particle size of the coconut shell fiber powder is 100 meshes; the enhancer is a composition of sodium polyacrylate and polyethylene oxide in a mass ratio of 0.8:1; and the thickener is a composition of sodium alginate and carboxymethyl cellulose in a mass ratio of 1.2:1.

[0036] The preparation method of the starch substitute is as follows: turmeric starch, coconut shell fiber, thickener and enhancer are mixed according to the weight ratio, added into a grinder, and ground until all of them pass through a 100-mesh sieve to obtain the starch substitute.

[0037] This embodiment continues to provide a method for applying sizing to the surface of boxboard: The starch substitute and corn starch (the amount of the starch substitute is 47wt% of the corn starch in the surface sizing agent of the boxboard, that is, the mass ratio of the starch substitute and corn starch is 47:53) are added to the mixing tank to prepare a water slurry with a mass concentration of 8%, stirred evenly, and then pumped into the gelatinization tank, heated to 95°C, and ammonium persulfate (the amount of ammonium persulfate added is 3wt‰ of the total mass of starch) is added for oxidation, and the pH is adjusted to 4.1 (±0.3) with aluminum sulfate, gelatinized for 39 minutes, and the viscosity is controlled at 11.5-12.5 seconds (measured with a 4# coating cup), and then cooled to 70-80°C for insulation, pumped into the insulation tank, and then the boxboard is surface sized on the machine. The quality of the boxboard obtained by the original sizing process of the enterprise is compared after testing, and the test results are as shown in Table 4: Table 4

[0038] Example 5 This embodiment provides a starch substitute and a preparation method thereof: The raw materials for preparing the starch substitute include, by weight, 30 parts of turmeric starch, 10 parts of coconut shell fiber powder, 2.5 parts of thickener, and 2.5 parts of enhancer: wherein the particle size of the turmeric starch is 120 meshes, and the particle size of the coconut shell fiber powder is 100 meshes; the enhancer is a composition of polyvinyl alcohol and polyethylene oxide in a mass ratio of 1.5:1.0; and the thickener is carboxymethyl cellulose.

[0039] The preparation method of the starch substitute is as follows: turmeric starch, coconut shell fiber, thickener and enhancer are mixed according to the weight ratio, added into a grinder, and ground until all of them pass through a 100-mesh sieve to obtain the starch substitute.

[0040] This embodiment continues to provide a method for applying sizing to the surface of boxboard: The starch substitute and corn starch (the amount of the starch substitute is 45wt% of the corn starch in the surface sizing agent of the boxboard, that is, the mass ratio of the starch substitute and corn starch is 45:55) are added to the mixing tank to prepare a water slurry with a mass concentration of 8%, stirred evenly, and then pumped into the gelatinization tank, heated to 92°C, and ammonium persulfate (the amount of ammonium persulfate added is 3wt‰ of the total mass of starch) is added for oxidation, and the pH is adjusted to 4.1 (±0.3) with aluminum sulfate, gelatinized for 39 minutes, and the viscosity is controlled at 11.5-12.5 seconds (measured with a 4# coating cup), and then cooled to 70-80°C for insulation, pumped into the insulation tank, and then the boxboard is put on the machine for surface sizing. The quality of the boxboard with the original sizing process of the enterprise is tested and compared, and the test results are as shown in Table 5: Table 5

[0041] As shown in Tables 1 to 5 above, the experimental data of the starch substitute for sizing of boxboard prepared by the present invention are compared with the paper samples of enterprises, and its tear length, bursting index, transverse folding resistance, surface water absorption and other indicators are better than the comparative paper samples of enterprises. This shows that the substitute is a starch substitute for sizing of boxboard with excellent performance, and its main raw materials are all from natural plants, which are by-products or wastes of other plant processing, are environmentally friendly, and are low in price, which can bring greater economic benefits to enterprises.

[0042] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited by the description of the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

[0043] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A starch substitute, characterized in that: The raw materials for preparing the starch substitute include, by weight, 20 to 70 parts of turmeric starch, 10 to 30 parts of coconut shell fiber powder, 1 to 3 parts of thickener, and 1 to 3 parts of enhancer.

2. The starch substitute according to claim 1, characterized in that The particle size of the turmeric starch is 120 meshes.

3. The starch substitute according to claim 1, characterized in that The particle size of the coconut shell fiber powder is 100 meshes.

4. The starch substitute according to claim 1, characterized in that The reinforcing agent is at least one of polyvinyl alcohol, cationic polyacrylamide and polyethylene oxide; preferably, the molecular weight of the cationic polyacrylamide is 5 million to 8 million.

5. The starch substitute according to claim 1, characterized in that The thickener is at least one of sodium alginate, chitosan, sodium polyacrylate, guar gum and carboxymethyl cellulose.

6. A method for preparing the starch substitute according to any one of claims 1 to 5, characterized in that: The turmeric starch, coconut shell fiber, thickener and enhancer are mixed according to the weight ratio, added into a grinder, and ground until all of them pass through a 100-mesh sieve to obtain the starch substitute.

7. Use of the starch substitute according to any one of claims 1 to 5 or the starch substitute obtained by the preparation method according to claim 6, characterized in that: The starch substitute is used to replace 20 wt% to 50 wt% of the original starch in the surface sizing agent of the boxboard; preferably, the original starch is selected from at least one of corn starch and cassava starch.

8. A method for sizing the surface of boxboard, characterized in that: The method comprises: The starch substitute according to any one of claims 1 to 5 or the starch substitute obtained by the preparation method according to claim 6 is mixed with the original starch in the surface sizing agent of the boxboard to prepare a water slurry with a mass concentration of 6% to 10%, and the mixture is heated to 85°C to 95°C, and ammonium persulfate is added at the same time. The pH is adjusted to 3.5 to 4.5 with aluminum sulfate, and gelatinized for 20min to 45min, the viscosity is controlled to 11.5s to 12.5s, and then the mixture is cooled to 70°C to 80°C for insulation, and then the boxboard is surface sizing is performed on the machine.

9. The method according to claim 8, characterized in that The amount of the starch substitute is 20wt% to 50wt% of the original starch in the surface sizing agent for boxboard paper; And / or, the amount of ammonium persulfate added is 3wt‰ to 4wt‰ of the total mass of starch; And / or, the native starch in the surface sizing agent for boxboard is selected from at least one of corn starch and cassava starch.

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