Ultra-thin high-strength corrugated paper and production process thereof

Abstract

The application discloses an ultrathin high-strength corrugated paper and a production process thereof, and particularly relates to the technical field of corrugated paper. The process comprises the following steps: mixing different kinds of waste paper raw materials, and obtaining original waste paper pulp through hydraulic pulping; feeding the original waste paper pulp into a grading screen after high-concentration sand removal, coarse screening and low-concentration sand removal, and screening the fibers in the waste paper pulp into long fibers and short fibers; mixing the long fiber pulp and the short fiber pulp in a certain proportion, and performing papermaking and surface sizing treatment; obtaining the ultrathin high-strength corrugated paper; the papermaking comprises the following steps: adding polydimethyl diallyl ammonium chloride into the fiber slurry in a papermaking pool to perform modification treatment; and using a mixed solution of starch glue, solid surface sizing agent, benzene propyl surface sizing agent, 2,3-epoxy propyl trimethyl ammonium chloride and alkenyl succinic anhydride as a surface sizing agent to perform surface sizing treatment. Through the in-pulp-surface double modification mode, the fiber strength and the waterproof performance of the ultrathin corrugated paper are significantly improved while the thinness is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of corrugated paper, in particular to a kind of ultra-thin high-strength corrugated paper and its production process. BACKGROUND

[0002] Waste paper, also known as secondary fiber, refers to old paper that has been used as raw material for papermaking. The papermaking industry recycles a large amount of waste paper, which not only reduces waste production and potential harm to the environment, but also recycles waste paper resources to achieve economic benefits and protect the ecological environment from the source.

[0003] Corrugated paper boxes are made of corrugated paper. Due to its multi-layer structure and good strength, it is widely used in packaging and transportation. During the loading process, the corrugated paper needs to be folded multiple times to form a specific shape. However, due to the thick thickness of the existing corrugated paper, the flexibility and foldability of the corrugated paper are poor during folding, which reduces its application in packaging performance.

[0004] With the rapid growth of demand for American waste in the domestic market, the American waste market will face a situation of supply not meeting demand and price rising, and the price of paper will also rise; In addition, the government's control standards for the import of foreign waste have been further upgraded, and the direct import of foreign waste has gradually decreased. However, papermaking enterprises using domestic waste as raw material have reduced quality due to multiple recycling of raw materials, and high-strength corrugated paper produced from such raw materials can only be considered as medium-low corrugated paper. For example, Chinese patent CN108215314A, a low-cost corrugated paper box production process, includes the following steps: breaking down waste paper, beating, mixing pulp, paper pulp, hot bonding paper, paper pressing line, slotting, printing and bonding. Through the synergistic effect of various raw materials and processing steps, the corrugated paper box has high structural strength, small packaging space, and due to the reduction of the thickness of the single corrugated paper, the volume of the corrugated paper box itself is also reduced to some extent, saving storage and transportation costs. Although this patent uses waste paper, the corrugated paper produced by it mainly uses short fibers, which reduces the strength of the corrugated paper during the reduction of thickness, and the thickness reduction is limited. In addition, the patent uses a gluing machine for gluing, although the glue is not specified in detail, but the conventional sizing agent is usually used, which has limited effect on improving the strength of the paper, and the conventional sizing agent has limited resistance to content and external pressure.

[0005] The patent CN109537349A discloses a production process of a low-basis-weight high-strength corrugated box. The slurry used in the process comprises 2-4 parts by weight of silicon dioxide, 1-3 parts by weight of ethylene-propylene-diene rubber, 2-5 parts by weight of vinyl acetate, and 10-15 parts by weight of polyethylene fiber. The use of the slurry effectively improves the strength and durability of the corrugated paperboard, and the corrugated paperboard can withstand greater impact pressure without deformation. However, the patent has limited improvement on the surface strength of the corrugated paper, and the use of wheat straw and wood bamboo with high long fiber content limits the utilization of waste paper boxes. The corrugated paper obtained by the patent still cannot meet the requirements of thinness and high strength. SUMMARY

[0006] To solve the above problems, the present application provides an ultra-thin high-strength corrugated paper and a production process thereof.

[0007] To achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0008] According to one aspect of the present application, a production process of an ultra-thin high-strength corrugated paper is provided, which comprises the following steps:

[0009] Step one: mixing different types of waste paper raw materials by hydraulic pulping to obtain raw waste paper pulp with a concentration of 2.5-2.8%;

[0010] Step two: after high-concentration sand removal, coarse screening, and low-concentration sand removal, the raw waste paper pulp is fed into a grading screen to separate the fibers in the waste paper pulp into long fibers and short fibers;

[0011] Step three: mixing the long fiber pulp and the short fiber pulp in a certain proportion, and performing papermaking and surface sizing treatment to obtain an ultra-thin high-strength corrugated paper;

[0012] In the papermaking process, polydimethyl diallyl ammonium chloride is added to the fiber slurry in the papermaking pool for modification treatment. In the modification treatment, the amount of polydimethyl diallyl ammonium chloride is 1-3 parts by weight based on 100 parts of fiber dry weight.

[0013] In the surface sizing process, a mixture of starch glue, solid surface sizing agent, benzene propyl surface sizing agent, 2,3-epoxy propyl trimethyl ammonium chloride, and alkenyl succinic anhydride is used as the surface sizing agent for surface sizing treatment. In the surface sizing process, the amount of starch glue is 40-45 kg, the amount of solid sizing agent is 8-10 kg, the amount of benzene propyl surface sizing agent is 2-3 kg, the amount of 2,3-epoxy propyl trimethyl ammonium chloride is 0.3-1 kg, and the amount of alkenyl succinic anhydride is 0.5-1.5 kg based on 1 ton of unsized paper.

[0014] Further, in the step one, the waste paper raw material includes 45-55wt% of mixture of industrial carton waste paper and special waste paper, 25-30wt% of pit card paper, 10-15wt% of industrial paper edge waste paper, and 5-15wt% of dry ground pulp package.

[0015] Further, in the step two, the long fiber is subjected to low concentration sand removal again, precision screening using a 0.15-0.18mm gap screen drum, and concentration treatment, and is formed into pulp after being milled into a pulp with a beating degree of 39-41°SR, and is transported to a long fiber pulp pool; the short fiber is subjected to concentration treatment, and is formed into pulp and transported to a short fiber pulp pool. Generally, long fibers are greater than 1.8mm, and short fibers are less than or equal to 1.8mm. In the present application, long fibers are greater than 2.5mm, and the proportion of long fibers greater than 2.5mm is more than 90%.

[0016] Further, the long fiber pulp and the short fiber pulp in the papermaking pool are mixed in a ratio of (3-7):(7-3) to form a pulp in the papermaking pool, and polydimethyl diallyl ammonium chloride is added for modification treatment. The temperature of the papermaking pool is less than 45℃, which reduces the risk of charge reversal.

[0017] Further, in the step three, the paper is subjected to mechanical dewatering and drying treatment before sizing to obtain unsized paper.

[0018] Further, the pressure of the mechanical dewatering is 900-1100KN / m.

[0019] Further, the drying treatment before sizing includes treatment at a temperature of 40-90℃ until the paper dryness is 90-92%, and the drying treatment after sizing includes treatment at a temperature of 60-90℃ until the paper dryness is 85-92%. The drying temperature and the paper dryness before and after sizing must be strictly controlled in the present application, and too high or too low temperature will easily reduce the strength and other properties of the corrugated base paper.

[0020] Further, the preparation process of the surface sizing agent is as follows: 2,3-epoxypropyltrimethylammonium chloride is mixed and modified with starch glue, and then solid sizing agent, phenylpropyl surface sizing agent, and alkenyl succinic anhydride are added and uniformly mixed.

[0021] The starch glue is first modified with 2,3-epoxypropyltrimethylammonium chloride to increase the charge density of 2,3-epoxypropyltrimethylammonium chloride and starch grafting; the solid surface sizing agent and the phenylpropyl surface sizing agent can further enhance water resistance and improve surface strength, and the alkenyl succinic anhydride (ASA) can be instantaneously cured to further resist water.

[0022] As an example, 2,3-epoxypropyltrimethylammonium chloride is preferably mixed and modified with the starch glue solution at 60 DEG C for 30 min, and then alkenyl succinic anhydride, phenylpropyl emulsion and solid surface sizing agent are sequentially added.

[0023] Further, the concentration of the starch glue solution is 8-12 wt%, and the viscosity is 30-40 mpa.s.

[0024] According to another aspect of the present application, an ultra-thin high-strength corrugated paper prepared by the above production process is provided, characterized in that the basis weight of the corrugated paper is 80-110 g / m 2 . As an example, the basis weight of the corrugated paper is preferably 80-90 g / m 2 . The thickness is preferably 0.12-0.18 mm.

[0025] The present application has the following advantages:

[0026] The present application uses different types of waste paper for mixing, covering the main types of packaging waste paper. Compared with the traditional process which only relies on a single waste paper (such as OCC) or needs to add additional external waste, the present application fully utilizes the domestic recycled waste paper resources by multi-element waste paper ratio, reduces the dependence on external waste (such as American waste), and meets the resource recycling policy. The present application adds dry ground pulp packs which are rich in long fibers (such as unbleached chemical pulp fibers), which can make up for the short and broken fiber problem caused by multiple recycling of other waste papers (such as industrial carton waste paper, paper edge waste paper), and improve the overall fiber length and strength of the raw materials, providing a high-quality basis for the preparation of long fiber pulp.

[0027] The present application introduces dry ground pulp packs and optimizes the ratio of each raw material to ensure the high-strength skeleton of the net corrugated paper.

[0028] The present application improves the fiber strength and water resistance of the ultra-thin corrugated paper by the method of internal-surface double modification.

[0029] The present application adds polydimethyl diallyl ammonium chloride in the fiber slurry to neutralize anionic impurities (such as hemicellulose), improve the binding force between fibers and improve the fiber dispersion, and at the same time provide adsorption sites for subsequent sizing agents (the surface is positively charged, and it is easier to adsorb the negatively charged alkenyl succinic anhydride); in the subsequent surface sizing agent, starch glue is used as the film-forming matrix, and at the same time, the "fiber-starch-phenylpropyl surface sizing agent" film structure is formed by using phenylpropyl surface sizing agent and starch glue to improve water resistance, the charge relay is formed by solid sizing agent and polydimethyl diallyl ammonium chloride to improve the retention rate of fine fibers, enhance the fiber network, and cross-link the alkenyl succinic anhydride and the phenylpropyl surface sizing agent to form a dense film layer, so that the ring pressure strength is further improved, and the 2,3-epoxypropyl trimethyl ammonium chloride in the surface sizing further strengthens the cationic network, promotes the directional arrangement of alkenyl succinic anhydride and phenylpropyl surface sizing agent on the fiber surface, and at the same time reacts with cellulose hydroxyl to generate ether bond, improving water resistance.

[0030] In the process of preparing the surface sizing agent, the 2,3-epoxypropyl trimethyl ammonium chloride is mixed and modified with the starch glue, and then the solid sizing agent, the phenylpropyl surface sizing agent and the alkenyl succinic anhydride are added and uniformly mixed, which can effectively prevent the flocculation caused by the reverse of the surface charge of the fibers, thereby avoiding the great reduction of the effect of the surface sizing agent. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained from the provided drawings without creating labor.

[0032] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not have technical significance to limit the conditions that the present application can be implemented, so any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that the present application can produce, should still fall within the scope of the technical content disclosed by the present application.

[0033] Figure 1 A pulp preparation process flow chart in the production of the super-thin high-strength corrugated base paper of embodiment 1 of the present application is provided.

[0034] Figure 2 A paper making process flow chart in the production of the super-thin high-strength corrugated base paper of embodiment 1 of the present application is provided. DETAILED DESCRIPTION

[0035] The present application will be described in greater detail by the following specific examples, and a person with ordinary skill in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. Obviously, the described examples are part of the embodiments of the present application, rather than all the embodiments. Based on the examples in the present application, all other embodiments obtained by a person with ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0036] In the present application, special grade waste paper is divided into special grade waste paper box (X0) and special grade mixed waste paper (HH0). The special grade waste paper box (X0) refers to a composite packaging paper box composed of all original wood pulp, with basically consistent color of each layer, no obvious color difference, no recycled pulp or other pulp components. The special grade mixed waste paper (HH0) is mainly white paper cutting edge without binding, film coating and printing, office white waste paper without printing and pure white double-coated paper, etc.

[0037] Kraft paper from the mill: Kraft paper generally refers to corrugated paper, and mill paper usually refers to the edge scraps or waste products generated during the production process of the paper box factory. The kraft paper from the mill is mainly composed of corrugated paper edge scraps, waste paper boxes, etc., and usually has a yellow color with a certain proportion of recycled fibers.

[0038] Mixed market waste paper: mainly refers to the waste paper generated in shopping malls, supermarkets and other places, which has complex components and may contain various packaging paper, brochures, label paper, etc., and usually contains a certain amount of colored paper and film-coated paper.

[0039] Dry ground pulp bag: waste paper pulp bag generated during the papermaking process, which is formed after drying treatment. It is mainly composed of pulp fibers and is usually relatively pure, but may contain a small amount of additives or residues. Shenzhen Dacheng New Energy Technology Co., Ltd., Vietnam imports dry ground pulp bags. The long fibers in the dry ground pulp bag are usually more than 2.5 mm, while the long fibers in the ordinary waste paper box are usually more than 2.0 mm.

[0040] Industrial paper box waste paper: mainly comes from packaging paper boxes in the industrial production process, usually kraft paper boxes, with high strength and good fiber quality, and usually light yellow in color.

[0041] Industrial paper edge waste paper: is the paper edge scraps generated in the industrial production process, such as cutting edge scraps generated in printing factories, paper box factories, etc., which are usually neat, have good fiber quality, and have relatively simple components, mainly virgin fibers or slightly contaminated recycled fibers.

[0042] Solid surface sizing agent (model: QN-388, Taian Qiniu Chemical Technology Co., Ltd.);

[0043] Phenylpropyl surface sizing agent (model: MX-611, Mingxiang Chemical Technology (Shandong) Group Co., Ltd.);

[0044] Starch glue: Yongguzhichang, item number: CD606;

[0045] 2,3-epoxypropyltrimethylammonium chloride: CAS 3033-77-0;

[0046] Alkenyl succinic anhydride (ASA): CAS 25377-73-5.

[0047] Example 1

[0048] The present embodiment provides a production process of an ultra-thin high-strength corrugated paper. The waste paper raw material is: 50wt% of waste paper (a mixture of industrial carton waste paper and special waste paper, mixed market waste paper), 27wt% of pit card paper, 13wt% of industrial paper edge waste paper, and 10wt% of dry ground pulp package. The pulp production process is as shown in Figure 1 , and the paper making process is as shown in Figure 2 . The specific steps are as follows:

[0049] 1) Disintegration and screening: the above waste paper raw material is sent into a hydraulic pulper by a chain plate machine for hydraulic shearing disintegration, then sent into a high-concentration sand remover for two-stage high-concentration sand removal to preliminarily separate impurities, and then sent into a pulp tower for storage, and then transported to a screening section for three-stage coarse screening to remove large-size impurities, and then four-stage low-concentration sand removal is performed to further remove heavy impurities such as sand and metal scraps in the pulp to obtain fiber coarse pulp;

[0050] 2) Fiber classification: the fiber coarse pulp is separated into long fiber coarse pulp (the length of long fiber is more than 2.5mm) and short fiber coarse pulp (the length of short fiber is less than 1.8mm) according to length by using a classification screen;

[0051] 3) Impurity removal and fiber fine screening: the long fiber is again subjected to four-stage low-concentration sand removal, then three-stage fine screening is performed using a screen drum with a 0.18mm gap, and then concentration treatment is performed by a multi-disc thickener (the concentration of the concentrated long fiber pulp is 4.5wt%), and the pulp is milled at a beating degree of 40°SR to loosen the fiber to obtain long fiber pulp and transport it to a long fiber pulp pool; the short fiber coarse pulp is subjected to concentration treatment by a multi-disc thickener (the concentration of the concentrated short fiber pulp is 4.5wt%) to obtain short fiber pulp and transport it to a short fiber pulp pool;

[0052] 4) Slurry preparation and storage: the fibers in the long fiber pulp and the short fiber pulp are mixed in a weight ratio of 1:1 into a papermaking pool to form uniform pulp with a concentration of 4.5wt%, and polydimethyl diallyl ammonium chloride (2 parts of polydimethyl diallyl ammonium chloride are added for every 100 parts of fiber dry weight) is added for modification treatment;

[0053] 5) forming and dewatering: the paper pulp is uniformly distributed and flowed to the paper machine at a concentration of 1% to the wire section for web forming, the fibers are interwoven into a wet paper web in the wire section, and then the wet paper web is mechanically dewatered at a pressure of 1000 KN / m in the press section and dried at a temperature of 65°C to a paper dryness of 91% to obtain an un-sized paper;

[0054] 6) surface sizing and drying treatment: first, 2,3-epoxypropyltrimethylammonium chloride 0.6 kg is mixed and modified with starch sizing agent 43 kg (concentration of 10 wt%, viscosity of 35 mpa.s), then solid sizing agent 8 kg, benzene propyl surface sizing agent 3 kg, and alkenyl succinic anhydride 1 kg are added and uniformly mixed to prepare a surface sizing agent; then the above surface sizing agent is used for sizing treatment of 1 ton of un-sized paper, and then dried at a temperature of 75°C to a paper dryness of 89%;

[0055] 7) winding and slitting: the paper web is wound and cut by a winding machine, and cut according to the customer's required specifications.

[0056] 8) packing and storage: the finished product is packed and stored.

[0057] Example 2

[0058] The embodiment provides a production process of an ultra-thin high-strength corrugated base paper, and the waste paper raw material is: waste paper (a mixture of industrial carton waste paper and special waste paper, mixed market waste paper) accounts for 55 wt%, pit card paper accounts for 27 wt%, industrial paper edge waste paper accounts for 13 wt%, and dry ground pulp accounts for 5 wt%, and the specific steps are as follows:

[0059] 1) disintegration and screening: the above waste paper raw material is sent into a hydraulic pulper by a chain plate machine for hydraulic shearing disintegration, then sent into a high-concentration sand remover for two-stage high-concentration sand removal to preliminarily separate impurities, and then sent into a pulp tower for storage, and then sent to a screening section for three-stage coarse screening to remove large-size impurities, and then four-stage low-concentration sand removal is performed to further remove heavy impurities such as sand and metal scraps in the pulp to obtain fiber coarse pulp;

[0060] 2) fiber classification: the fibers in the fiber coarse pulp are separated into long fiber coarse pulp (the length of the long fibers is greater than 2.5 mm) and short fiber coarse pulp (the length of the short fibers is less than 1.8 mm) by a classification screen;

[0061] 3) impurity removal and fiber fine screening: the long fibers are again subjected to four-stage low-concentration sand removal, then subjected to three-stage fine screening by using a screen drum with a 0.18 mm gap, and then subjected to concentration treatment by a multi-disc thickener (the concentration of the concentrated long fiber pulp is 4.5 wt%) to control the beating degree of 41°SR to defibrate the fibers to obtain long fiber pulp and send it to a long fiber pulp pool; the short fiber coarse pulp is subjected to concentration treatment by a multi-disc thickener (the concentration of the concentrated short fiber pulp is 4.5 wt%) to obtain short fiber pulp and send it to a short fiber pulp pool;

[0062] 4) mixing and storage: the long fiber pulp and the short fiber pulp are mixed in a weight ratio of 1:1 to form a uniform pulp with a concentration of 4wt% in the papermaking pool, and polydimethyl diallyl ammonium chloride is added (1 part of polydimethyl diallyl ammonium chloride is added for every 100 parts of fiber dry weight) for modification treatment;

[0063] 5) forming and dewatering: the pulp is uniformly distributed and flowed to the paper machine at a concentration of 0.5% to form a wet paper web in the wire section, and the fibers are interwoven in the wire section to form a wet paper web, which is then mechanically dewatered by a press section at a pressure of 900KN / m and dried at a temperature of 40℃ to a paper dryness of 90% to obtain an unsized paper;

[0064] 6) surface sizing and drying treatment: 2,3-epoxypropyltrimethylammonium chloride 0.6kg is mixed and modified with starch sizing agent 40kg (concentration 12wt%, viscosity 40mpa.s), then solid sizing agent 10kg, benzene propyl surface sizing agent 3kg, and alkenyl succinic anhydride 0.5kg are added and uniformly mixed to prepare a surface sizing agent; then the above surface sizing agent is used for sizing treatment of 1 ton of unsized paper, and then dried at a temperature of 90℃ to a paper dryness of 92%;

[0065] 7) winding and slitting: the paper web is wound and cut by a winding machine according to the customer's demand specifications.

[0066] 8) packing and storage: the finished product is packed and stored.

[0067] Example 3

[0068] The present embodiment provides a production process of ultra-thin high-strength corrugated paper, and the waste paper raw material is: waste paper (a mixture of industrial carton waste paper and special waste paper, mixed market waste paper) accounts for 45wt%, pit card paper accounts for 27wt%, industrial paper edge waste paper accounts for 13wt%, and dry grinding pulp accounts for 15wt%, and the specific steps are as follows:

[0069] 1) disintegration and screening: the above waste paper raw material is sent into a hydraulic pulper by a chain plate machine for hydraulic shearing disintegration, then sent into a high-concentration sand remover for two-stage high-concentration sand removal to preliminarily separate impurities, and then sent into a pulp tower for storage, and then sent to a screening section for three-stage coarse screening to remove large-size impurities, and then four-stage low-concentration sand removal is carried out to further remove heavy impurities such as sand and metal scraps in the pulp to obtain fiber coarse pulp;

[0070] 2) fiber classification: the fiber coarse pulp is separated into long fiber coarse pulp (long fiber length is more than 2.5mm) and short fiber coarse pulp (short fiber length is less than 1.8mm) according to length by a classification screen;

[0071] 3) Impurity removal and fiber fine screening: the long fibers are subjected to four-stage low-concentration sand removal, followed by three-stage fine screening using a screen drum with a 0.18 mm gap, and then concentrated by a multi-disc thickener (the concentration of the concentrated long fiber slurry is 4.5 wt%) to control the 39°SR beating degree for refining to loosen the fibers, and then the long fiber pulp is obtained and transported to the long fiber pulp pool; the short fiber thick pulp is concentrated by a multi-disc thickener (the concentration of the concentrated short fiber slurry is 4.5 wt%) to obtain the short fiber pulp and transport it to the short fiber pulp pool;

[0072] 4) Slurry preparation and storage: the long fiber pulp and the short fiber pulp are mixed in a weight ratio of 1:1 to form a uniform paper pulp with a concentration of 5 wt% in the papermaking pool, and polydimethyl diallyl ammonium chloride (3 parts of polydimethyl diallyl ammonium chloride are added for every 100 parts of fiber dry weight) is added for modification treatment;

[0073] 5) Forming and dewatering: the paper pulp is uniformly distributed and flowed to the paper machine at a concentration of 1.5% to form a wet paper web in the wire section, and then the fibers are interwoven into a wet paper web, which is then mechanically dewatered by a press section at a pressure of 1100 KN / m and dried at a temperature of 90°C to a paper dryness of 92% to obtain an un-sized paper;

[0074] 6) Surface sizing and drying treatment: first, 2,3-epoxypropyltrimethylammonium chloride 1 kg is mixed and modified with starch sizing agent 45 kg (concentration 8 wt%, viscosity 30 mpa.s), then solid sizing agent 8 kg, benzene propyl surface sizing agent 2 kg, and alkenyl succinic anhydride 1.5 kg are added and uniformly mixed to prepare a surface sizing agent; then the above surface sizing agent is used for sizing treatment of 1 ton of un-sized paper, and then dried at a temperature of 60°C to a paper dryness of 85%;

[0075] 7) Winding and slitting: the paper web is wound and cut by a winding machine according to the customer's required specifications.

[0076] 8) Packaging and storage: the finished product is packaged and stored.

[0077] Example 4

[0078] This example provides a production process for ultra-thin high-strength corrugated paper, which is different from Example 1 in that in step 4) the long fibers and short fibers are mixed in a weight ratio of 3:7, and the other conditions are the same as in Example 1.

[0079] Example 5

[0080] This example provides a production process for ultra-thin high-strength corrugated paper, which is different from Example 1 in that in step 4) the long fibers and short fibers are mixed in a weight ratio of 4:6, and the other conditions are the same as in Example 1.

[0081] Example 6

[0082] The embodiment provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that long fibers and short fibers are mixed in a weight ratio of 6:4 in step 4), and other conditions are the same as those in the embodiment 1.

[0083] Embodiment 7

[0084] The embodiment provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that long fibers and short fibers are mixed in a weight ratio of 7:3 in step 4), and other conditions are the same as those in the embodiment 1.

[0085] Comparative example 1

[0086] The comparative example provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that no polydimethyl diallyl ammonium chloride is added in step 4), and other conditions are the same as those in the embodiment 1.

[0087] Comparative example 2

[0088] The comparative example provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that no 2,3-epoxypropyl trimethyl ammonium chloride is added in step 6), and other conditions are the same as those in the embodiment 1.

[0089] Comparative example 3

[0090] The comparative example provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that no phenylpropyl surface sizing agent is added in step 6), and other conditions are the same as those in the embodiment 1.

[0091] Comparative example 4

[0092] The comparative example provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that no alkenyl succinic anhydride is added in step 6), and other conditions are the same as those in the embodiment 1.

[0093] Comparative example 5

[0094] The comparative example provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that the amount of polydimethyl diallyl ammonium chloride is 5 parts in step 4) based on 100 parts of fiber dry weight; the amount of starch sizing liquid is 44.1 kg, the amount of solid sizing agent is 8 kg, the amount of phenylpropyl surface sizing agent is 1 kg, the amount of 2,3-epoxypropyl trimethyl ammonium chloride is 0.5 kg, and the amount of alkenyl succinic anhydride is 2 kg in step 6) based on 1 ton of unsized paper, and other conditions are the same as those in the embodiment 1.

[0095] Comparative example 6

[0096] The embodiment provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that waste paper raw materials are as follows: waste paper (a mixture of industrial paper box waste paper and special waste paper, mixed market waste paper) accounts for 60wt%, pit card paper accounts for 27wt%, industrial paper edge waste paper accounts for 13wt%, and dry ground pulp accounts for 0wt%, long fibers are greater than 2.0mm (greater than 90% of 2.0-2.3mm), and short fibers are less than 1.8mm; and other conditions are the same as those in the embodiment 1.

[0097] Comparative example 7

[0098] The embodiment provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that the preparation process of the surface sizing agent in the step 6) is that 43kg of starch glue solution (10wt% in concentration and 35mpa.s in viscosity), 0.6kg of 2,3-epoxypropyltrimethylammonium chloride, 8kg of solid sizing agent, 3kg of benzene propyl surface sizing agent and 1kg of alkenyl succinic anhydride are blended, and other conditions are the same as those in the embodiment 1.

[0099] Comparative example 8

[0100] The embodiment provides a production process of super-thin high-strength corrugated paper, which is different from the embodiment 1 in that the drying treatment condition in the step 5) is 95 DEG C and a dryness of 94%, the drying treatment condition in the step 6) is 55 DEG C and a dryness of 80%, and other conditions are the same as those in the embodiment 1.

[0101] Test example 1

[0102] The super-thin (corrugated paper basis weight 80-110g / m 2 , thickness 0.12-0.18mm) high-strength corrugated paper prepared in the above embodiment and comparative examples is respectively subjected to performance testing, the basis weight is GB / T 451.2, the tightness is =basis weight / thickness, the thickness is ISO 534, the ring crush strength is GB / T 2679.8, the breaking length is GB / T 13023, and the water absorption is GB / T 1540, and the test results are shown in Tables 1 and 2.

[0103] Table 1

[0104] Quantitative (g / m 2 ) Thickness (mm) Example 1 82 0.125 Example 2 100 0.172 Example 3 95 0.155 Example 4 105 0.165 Example 5 90 0.155 Example 6 95 0.142 Example 7 105 0.173 Comparative Example 1 128 0.198 Comparative Example 2 85 0.155 Comparative Example 3 88 0.161 Comparative Example 4 90 0.152 Comparative Example 5 95 0.135 Comparative Example 6 125 0.211 Comparative Example 7 92 0.144 Comparative Example 8 91 0.151 Commercially available 140 0.561

[0105] Table 2

[0106]

[0107]

[0108] From Table 1 and Table 2, although the performance of Example 2 and 3 is also within the specified range, when the dry ground pulp package is 10%, the long and short fibers are synergistically optimal. When the dry ground pulp package is reduced or increased, the long fibers are insufficient or excessive, which will increase the basis weight and thickness, and slightly reduce the ring crush. By separately controlling the long and short fiber ratio (Examples 4-7), it is found that the closer to the long and short fiber ratio of 1:1, the better the performance indicators, and the long and short fiber ratio of 1:1 is the best.

[0109] Without adding a wet-end strength enhancer (Comparative Example 1), the fiber bonding force is reduced, the network structure is loose, and the tightness is reduced; without a surface epoxy modifier (Comparative Example 2), the film void increases, and the water absorption increases; without ASA (Comparative Example 4), the water resistance collapses, and the water absorption is the highest; directly blending the sizing agent (Comparative Example 7) will cause the charge to reverse, the sizing agent to flocculate, and the beating degree to decrease; without adding a dry ground pulp package (Comparative Example 6), only relying on the long fibers in the waste paper, the long fiber length is not enough, the long and short fiber ratio is out of balance, the basis weight increases, and the tightness decreases. Without adding a styrene-acrylic surface sizing agent (Comparative Example 3), the “fiber-starch-styrene-acrylic” composite film is destroyed, the ring crush index decreases, the water absorption increases, and the breaking length decreases. In Comparative Example 5, the amount of polydimethyl diallyl ammonium chloride and the amount of sizing agent are far more than in Example 1, but the excess positive charge will cause the potential of the fiber surface to reverse, the electrostatic repulsion between the fibers, and the uniformity of the paper sheet to be destroyed, and the ring crush index decreases; the excess ASA will cause the precipitate to block the capillary pores, the local water absorption to increase, and the ring crush to locally collapse; any excess or reduction of the additives will destroy the precise synergy of “charge relay-crosslinking film formation”, resulting in a comprehensive collapse of performance.

[0110] Although the present application has been described in detail by the general description and specific examples above, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A production process for ultra-thin high-strength corrugated base paper, characterized in that, The process includes: Step 1: Different types of waste paper raw materials are mixed and hydrated to obtain raw waste paper pulp with a concentration of 2.5-2.8%; Step 2: After passing through high-consistency desanding, coarse screening, and low-consistency desanding, the raw waste paper pulp enters the grading screen to separate the fibers in the waste paper pulp into long fibers and short fibers. Step 3: Mix long fiber pulp and short fiber pulp in a certain proportion, and then perform papermaking and surface sizing treatment to obtain ultra-thin high-strength corrugated base paper; Among them, papermaking includes adding polydimethyldiallyl ammonium chloride to the fiber slurry in the papermaking tank for modification treatment. In the modification treatment, the amount of polydimethyldiallyl ammonium chloride is 1 to 3 parts based on 100 parts of fiber dry weight. In the surface sizing process, a mixture of starch adhesive, solid surface sizing agent, styrene-acrylic surface sizing agent, 2,3-epoxypropyltrimethylammonium chloride, and alkenyl succinic anhydride is used as the surface sizing agent for surface sizing treatment. In the surface sizing process, based on 1 ton of unsizing paper, the amount of starch adhesive is 40-45 kg, the amount of solid sizing agent is 8-10 kg, the amount of styrene-acrylic surface sizing agent is 2-3 kg, the amount of 2,3-epoxypropyltrimethylammonium chloride is 0.3-1 kg, and the amount of alkenyl succinic anhydride is 0.5-1.5 kg. The preparation process of the surface sizing agent is as follows: first, 2,3-epoxypropyltrimethylammonium chloride is mixed and modified with starch adhesive, and then solid sizing agent, styrene-acrylic surface sizing agent and alkenyl succinic anhydride are added and mixed evenly to obtain the final product.

2. The production process of ultra-thin high-strength corrugated base paper according to claim 1, characterized in that, In step one, the waste paper raw materials include 45-55 wt% of a mixture of industrial cardboard waste paper and premium waste paper, 25-30 wt% of corrugated cardboard factory cardboard, 10-15 wt% of industrial paper scraps, and 5-15 wt% of dry pulp bales.

3. The production process of ultra-thin high-strength corrugated base paper according to claim 1, characterized in that, In step two, the long fibers undergo low-concentration sand removal again, fine screening using a sieve drum with a 0.15-0.18mm gap, concentration treatment, and pulping and shaping with a beating degree controlled at 39~41°SR to obtain long fiber pulp, which is then transported to the long fiber pulping tank; the short fibers undergo concentration treatment to obtain short fiber pulp, which is then transported to the short fiber pulping tank.

4. The production process of ultra-thin high-strength corrugated base paper according to claim 1, characterized in that, In the papermaking tank, long fiber pulp and short fiber pulp are mixed in a ratio of (3~7):(7~3) to form paper pulp, and polydimethyldiallylammonium chloride is added for modification treatment.

5. The production process of ultra-thin high-strength corrugated base paper according to claim 1, characterized in that, In step three, after papermaking, the paper undergoes mechanical dehydration and pre-sizing drying to obtain un-sizing paper.

6. The production process of ultra-thin high-strength corrugated base paper according to claim 5, characterized in that, The mechanical dehydration pressure is 900~1100KN / m.

7. The production process of ultra-thin high-strength corrugated base paper according to claim 5, characterized in that, The pre-sizing drying treatment includes treating the paper at a temperature of 40~90℃ until the paper dryness is 90~92%, and the post-sizing drying treatment includes treating the paper at a temperature of 60~90℃ until the paper dryness is 85~92%.

8. The production process of ultra-thin high-strength corrugated base paper according to claim 1, characterized in that, The starch solution has a concentration of 8-12 wt% and a viscosity of 30-40 mPa·s.

9. An ultra-thin high-strength corrugated base paper prepared by the production process according to any one of claims 1-8, characterized in that, The basis weight of the corrugated base paper is 80-110 g / m³. 2 .

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