Method for making high-grade packaging paper by mixing high card pulp and waste paper

Abstract

The invention discloses a method for making high-grade packaging paper by mixing high-card pulp and waste paper, which comprises the following steps: preparing OCC waste paper pulp, crushing, removing slag, coarse screening and grading screen the domestic waste OCC in sequence to form long, medium and short fiber pulps, and the long fiber pulp / medium fiber pulp / short fiber pulp is sequentially passed through a slag remover, a fine screen, a multi-disc concentrator, a hot dispersion, a pre-beating pool and a disc grinding and then enters a post-beating pool; preparing natural wood pulp, crushing the purchased commercial wood pulp raw material, and entering the post-beating pool after disc grinding and beating; preparing high-card pulp, crushing the wood chip raw material After washing and pre-impregnation → cooking → medium-consistency grinding → screening and purification → washing and concentration, high-card pulp is formed. The high-card pulp is mixed and beaten with long-fiber pulp and short-fiber pulp to form high-long mixed pulp and high-short mixed pulp respectively; finally, the prepared natural wood pulp and medium-fiber pulp, high-long mixed pulp and medium-fiber pulp and high-short mixed pulp, high-long mixed pulp and high-short mixed pulp are respectively put into the mixed pulp pool of the surface / core / bottom layer paper machine, and after removing impurities, they are sent to the surface / core / bottom layer wire section for papermaking, and then go through the pressing section → front drying → sizing → post drying → calendering → winding to make high-grade packaging paper.

Description

Technical field:

[0001] The invention relates to the technical field of papermaking, in particular to a method for making high-grade packaging paper by mixing high-card pulp and waste paper. Background technology:

[0002] At present, the raw materials used in domestic high-end packaging paper are mainly imported waste paper, with a small amount of domestic waste paper and natural wood pulp. However, with the deepening of the implementation of the national environmental protection policy, the import of foreign waste (i.e. imported waste paper) has been stopped, resulting in a shortage of domestic and foreign waste, and an increase in the use of domestic waste and wood pulp. Since most of the imported waste paper is made of virgin wood pulp, the strength of the finished paper is higher than that of domestic waste paper. However, after increasing the amount of domestic waste, the strength of the finished paper is difficult to meet the requirements of high-end packaging paper.

[0003] In order to improve the strength of packaging paper, a large amount of wood pulp is used, which leads to increased production costs. In order to adapt to market changes, enhance corporate competitiveness, reduce corporate production costs, and study new raw materials to replace imported waste paper, and produce high-quality, low-cost high-end packaging paper, it is an urgent task currently faced.

[0004] In view of this, the inventor proposes the following technical solution. Summary of the invention:

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for pulping high-grade packaging paper by mixing high-card pulp and waste paper. The method optimizes the production process by optimizing the raw material ratio, pulping process and the amount of chemical auxiliary materials added, and reasonably reduces the amount of wood pulp and chemical auxiliary materials while ensuring the strength of the finished paper, thereby reducing the papermaking production cost.

[0006] In order to solve the above technical problems, the present invention adopts the following technical scheme: A method for mixing high-card pulp and waste paper to make high-grade packaging paper comprises the following steps: S001: preparing OCC waste paper pulp: crushing, removing slag, coarse screening, and grading screening are performed on domestic waste OCC in sequence to form long-fiber pulp, medium-fiber pulp, and short-fiber pulp, and then the long-fiber pulp from the grading screening is sequentially passed through a slag remover, a fine screen, a multi-disc thickener, a thermal dispersion, a long-fiber beating front pool, and a disc grinder, and then enters a long-fiber beating back pool; then the medium-fiber pulp from the grading screening is slag removed, a fine screen, a multi-disc thickener, a thermal dispersion, a long-fiber beating front pool, and a disc grinder; After passing through the medium fiber cleaner, fine screen, multi-disc thickener, hot dispersion, medium fiber tapping front pool, and disc grinding, it enters the medium fiber tapping back pool; then the long fiber pulp from the graded screen passes through the medium fiber cleaner, fine screen, multi-disc thickener, hot dispersion, short fiber tapping front pool, and disc grinding, and then enters the short fiber tapping back pool; S002: Preparation of natural wood pulp: The purchased commercial wood pulp raw material is crushed by a hydraulic pulper, and then enters the back tapping pool after disc grinding; S003: Preparation of high card pulp: The wood chip raw material is washed and pre-soaked → steamed → Medium-consistency grinding → Screening and purification → Washing and concentration to form high-card pulp, which is stored in the pulp tower. After the high-card pulp is first beaten through the low-consistency disc grinding, it is added to the long fiber tapping pool and the short fiber tapping pool in step S001. The high-card pulp and long fiber pulp are mixed and beaten to form a high-long mixed pulp, which enters the long fiber tapping pool; the high-card pulp and short fiber pulp are mixed and beaten to form a high-short mixed pulp, which enters the short fiber tapping pool: S004: Paper machine production: The natural wood pulp and medium fiber pulp are put into the mixed pulp pool of the surface paper machine, and after removing impurities, they pass through the surface layer headstock box. The high-length mixed pulp, medium-length fiber pulp and high-short mixed pulp are put into the mixed pulp pool of the core layer paper machine, and after removing impurities, they are sent to the core layer wire section through the core layer headbox; the high-length mixed pulp and high-short mixed pulp are put into the mixed pulp pool of the bottom layer paper machine, and after removing impurities, they are sent to the bottom layer wire section through the bottom layer headbox; the surface layer, core layer and bottom layer pulps are dehydrated and formed through the wire section to form a wet paper web, and the three layers of pulp are compounded together, and then go through the press section → front drying → sizing → post drying → calendering → winding to make high-grade packaging paper.

[0007] Furthermore, in the above technical solution, in step S003, the specific preparation process of high card pulp is as follows: after the wood chip raw materials are washed and pre-impregnated, they are cooked in a digester to dissolve the lignin in the wood chip raw materials, so that the fibers in the wood chip raw materials are separated from each other into pulp, and the pulp is then beaten by medium-consistency grinding to fibrillate the wood chip fibers and dissociate them into single fibers and fiber bundles, and then the large fiber bundles, sand particles and metal particle impurities are removed through screening and purification equipment, and finally the cleanliness and concentration of the pulp are improved by washing and concentration to prepare high card pulp that meets quality requirements and is stored in a pulp tower.

[0008] Furthermore, in the above technical solution, in step S003, the prepared high card pulp, imported waste paper, and domestic waste are beaten to the same beating degree 30°SR for sheet measurement of bursting strength. The bursting strength of high card pulp is 3.84 Kpa.㎡ / g, the bursting strength of imported waste paper is 2.78 Kpa.㎡ / g, and the bursting strength of domestic waste is 1.8 Kpa.㎡ / g, that is, the bursting strength of high card pulp is 38% higher than that of imported waste paper, and 113% higher than that of domestic waste.

[0009] Furthermore, in the above technical solution, in step S003, the proportion of high-sticking pulp in the high-long mixed pulp is 0-30%; the proportion of high-sticking pulp in the high-short mixed pulp is 0-30%.

[0010] Further, in the above technical scheme, in step S001, the specific preparation process of OCC waste paper pulp is: the domestic waste OCC raw material is transported to the hydraulic pulper through the waste paper chain conveyor, the hydraulic pulper crushes the domestic waste OCC raw material, and then passes through the high-concentration cleaner, the high-concentration cleaner separates the metal and glass impurities in the pulp, and then passes through the coarse screen, the grading screen, the low-concentration cleaner, and the fine screen to further remove the impurities in the pulp, wherein the grading screen classifies the pulp into long-fiber pulp, medium-fiber pulp, and short-fiber pulp according to different fiber sizes, and each level of pulp is respectively passed through the concentrator to remove part of the water in the pulp, and after the concentration is increased, it enters the thermal dispersion equipment for treatment, and the thermal dispersion equipment disperses the hot melt in each level of pulp into particles invisible to the naked eye through the action of high temperature and mechanical force, so as to improve the appearance quality of the finished paper, and then the pulp of each level is beaten by the disc grinding and enters the respective post-beating pool.

[0011] Furthermore, in the above technical scheme, in step S002, the specific preparation process of natural wood pulp is: purchasing commodity natural wood pulp finished raw materials, sending them to the hydraulic pulper through a pulp chain conveyor, the hydraulic pulper pulping the finished wood pulp raw materials, and the concentration of the pulp after pulping is controlled at about 4-5%, and then sent to the wood pulp front pool, pumped to the wood pulp disc for beating, and after beating, it enters the post-beating pool, wherein the wood pulp disc is connected in series with three discs, the first disc adopts high-intensity beating, using a cutting-type grinding disc, and the pulping intensity is 3.0-4.5J / m; the second disc adopts medium-high intensity beating, and its pulping intensity is 2.5-3.0J / m; the third disc adopts medium intensity beating: the pulping intensity is 2.0-2.5J / m.

[0012] Furthermore, in the above technical scheme, the high-long mixed pulp formed by mixing the long fiber pulp with the high card pulp is pulped by three disc mills in series, wherein the first disc mill adopts high-intensity pulping, uses a cutting-type grinding wheel, and the pulping intensity is 3.0-4.5 J / m; the second disc mill adopts medium-high intensity pulping, and its pulping intensity is 2.5-3.0 J / m; the third disc mill adopts medium intensity pulping: the pulping intensity is 2.0-2.5 J / m; the medium fiber pulp is pulped by one disc mill, which adopts medium intensity pulping: the pulping intensity is 2.0-2.5 J / m; the high-short mixed pulp formed by mixing the short fiber pulp with the high card pulp is pulped by one disc mill, which adopts medium intensity pulping: the pulping intensity is 2.0-2.5 J / m; all the above disc mills use stainless steel ND90 grinding wheels.

[0013] Further, in the above technical scheme, in step S004, when producing 160-250g high-end packaging paper, the surface layer is quantitatively 25-35g / m2, the core layer is quantitatively 30-45g / m2, and the bottom layer is quantitatively 80-130g / m2, wherein the weight percentage of the surface layer pulp is: 20-50% natural wood pulp, 50-80% medium fiber pulp; the weight percentage of the core layer pulp is: 20-50% high-long mixed pulp, 3-30% medium fiber pulp, 50-80% high-short mixed pulp; the weight percentage of the bottom layer pulp is: 30-70% high-long mixed pulp, 30-60% high-short mixed pulp.

[0014] Further, in the above technical solution, in step S004, when the paper web passes through the pressing part for extrusion and dehydration, the pressing part adopts three-line pressing, wherein the first line pressing pressure is 700-780 kn / m, the second line pressing pressure is 1000-1200 kn / m, and the third line pressing pressure is 35-45 kn / m; after the paper web passes through the pressing part, it enters the front drying part for drying, and the paper web passing through the front drying part is glued by the glue machine, and a layer of glue for improving the surface strength of the finished paper is coated on the surface of the paper web, wherein the glue machine The front surface is glued by immersion glue, and the back surface is glued by scraper rod; after glue application, the paper web enters the post-drying section for drying, and the moisture content of the finished paper is controlled within the range of 8.0-9.0% through drying; the dried paper web enters the next calendering section, and the paper web passes through the calender heating roller under a certain pressure to press the paper sheet to make the thickness of the paper sheet uniform and improve the smoothness and glossiness of the paper sheet. The calender uses two-stage heating rollers for linear pressing, and finally after calendering treatment, it reaches the reel to be made into high-grade packaging paper.

[0015] Furthermore, in the above technical scheme, a dry strength agent is further added to the surface layer slurry, the core layer slurry and the bottom layer slurry, wherein the addition amount of the dry strength agent is 10-35KG / T; the main component of the dry strength agent is a polyacrylamide macromolecular polymer, which forms hydrogen bonds with the fibers to improve the strength of the paper; a reinforcing agent is further added to the core layer slurry / bottom layer slurry, wherein the addition amount of the reinforcing agent is 0-15KG / T; slurry starch is further added to the surface layer slurry and the core layer slurry, wherein the addition amount of the slurry starch is 3-10KG / T; the slurry starch is prepared by steaming amphoteric starch, the main component of amphoteric starch is prepared by modification of cassava starch, and the starch molecules have both anionic and cationic reaction groups of starch. Since the fibers are negatively charged, they are easily adsorbed by the cationic groups of the amphoteric starch, so that the fibers are combined to increase the strength of the paper.

[0016] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art: the present invention uses high card pulp to replace imported waste paper pulp, mixes with waste paper for pulping, and forms high-grade packaging paper. Compared with the prior art, the present invention uses high card pulp to replace the imported waste paper pulp originally used, and the amount of natural wood pulp used is reduced by 15-20%, and the amount of domestic waste is increased by 10-15%, which not only reduces the production cost of high-grade packaging paper, but also solves the problem of shortage of imported waste paper raw materials. In addition, the bursting strength of the self-made high card pulp of the present invention is higher than that of imported waste paper (U.S. waste), and the strength is higher than that of domestic waste, so that the bursting resistance, folding index, ring pressure index and other indicators of the high-grade packaging paper manufactured by the present invention are at a higher level, which improves the quality of the finished paper and can meet the quality requirements of customers. Furthermore, the process of making the self-made high card pulp of the present invention is also relatively simple, scientific and reasonable. In addition, the present invention improves the service life of the disc grinding plate and the fiber beating effect. By selecting the material and tooth shape of the grinding plate, the service life of the grinding plate is increased by about 20-30%, and the beating effect is increased by about 15-20%. Specific implementation method:

[0017] The present invention is further described below in conjunction with specific embodiments.

[0018] The present invention is a method for making high-grade packaging paper by mixing high card pulp and waste paper, which comprises the following steps:

[0019] S001: Preparation of OCC waste paper pulp: Domestic waste OCC is sequentially crushed, deslagging, coarsely screened, and graded to form long fiber pulp, medium fiber pulp, and short fiber pulp. The long fiber pulp from the graded screen is sequentially passed through a deslagging device, a fine screen, a multi-disc thickener, hot dispersion, a long fiber tapping fore-tank, and a disc grinder before entering a long fiber tapping post-tank; the medium fiber pulp from the graded screen is sequentially passed through a medium fiber deslagging device, a fine screen, a multi-disc thickener, hot dispersion, a medium fiber tapping fore-tank, and a disc grinder before entering a medium fiber tapping post-tank; the long fiber pulp from the graded screen is sequentially passed through a medium fiber deslagging device, a fine screen, a multi-disc thickener, hot dispersion, a short fiber tapping fore-tank, and a disc grinder before entering a short fiber tapping post-tank;

[0020] S002: Preparation of natural wood pulp: The purchased commercial wood pulp raw material is crushed by a hydraulic pulper, and then enters the post-beating pool after being beaten by a disc grinder;

[0021] S003: Preparation of high card pulp: The wood chips are washed and pre-soaked → cooked → medium-consistency grinding → screening and purification → washed and concentrated to form high card pulp, which is then stored in a pulp tower. The high card pulp is first pulped through a low-consistency disc mill and added to the long fiber tapping pool and the short fiber tapping pool in step S001. The high card pulp and long fiber pulp are mixed and beaten to form a high-long mixed pulp which enters the long fiber tapping pool; the high card pulp and short fiber pulp are mixed and beaten to form a high-short mixed pulp which enters the short fiber tapping pool:

[0022] S004: Paper machine production: natural wood pulp and medium fiber pulp are put into the mixed pulp pool of the surface paper machine, and after impurities are removed, they are sent to the surface layer wire section through the surface layer headbox; high long fiber mixed pulp, medium fiber pulp and high short fiber mixed pulp are put into the mixed pulp pool of the core layer paper machine, and after impurities are removed, they are sent to the core layer wire section through the core layer headbox; high long fiber mixed pulp and high short fiber mixed pulp are put into the mixed pulp pool of the bottom layer paper machine, and after impurities are removed, they are sent to the bottom layer wire section through the bottom layer headbox; the surface layer, core layer and bottom layer pulps are dehydrated and formed through the wire section to form a wet paper web, and the three layers of pulp are compounded together, and then go through the press section → front drying → sizing → post drying → calendering → winding to make high-grade packaging paper.

[0023] The present invention uses high card pulp to replace imported waste paper pulp, mixes it with waste paper for pulping, and forms high-end packaging paper. Compared with the prior art, the present invention uses high card pulp to replace the imported waste paper pulp originally used, and the amount of natural wood pulp used is reduced by 15-20%, and the amount of domestic waste is increased by 10-15%, which not only reduces the production cost of high-end packaging paper, but also solves the problem of shortage of imported waste paper raw materials. In addition, the bursting strength of the self-made high card pulp of the present invention is higher than that of imported waste paper (U.S. waste), and is higher than that of domestic waste, so that the bursting resistance, folding index, ring crush index and other indicators of the high-end packaging paper manufactured by the present invention are at a relatively high level, which improves the quality of the finished paper and can meet the quality requirements of customers. Furthermore, the process of making the self-made high card pulp of the present invention is also relatively simple, scientific and reasonable.

[0024] In step S001, the specific preparation process of OCC waste paper pulp is as follows: domestic waste OCC raw materials are transported to the hydraulic pulper through the waste paper chain conveyor, and the hydraulic pulper crushes the domestic waste OCC raw materials, and then passes through the high-concentration cleaner, which separates the metal and glass impurities in the pulp, and then passes through the coarse screen, the grading screen, the low-concentration cleaner, and the fine screen to further remove the impurities in the pulp, wherein the grading screen classifies the pulp into long-fiber pulp, medium-fiber pulp, and short-fiber pulp according to different fiber sizes, and each level of pulp is respectively passed through the concentrator to remove part of the water in the pulp, and after the concentration is increased, it enters the thermal dispersion equipment for treatment, and the thermal dispersion equipment disperses the hot melt in each level of pulp into particles invisible to the naked eye through the action of high temperature and mechanical force, so as to improve the appearance quality of the finished paper (i.e., high-end packaging paper), and then the pulp of each level is beaten by the disc grinding and enters the respective post-beating pool.

[0025] The hydraulic pulper has a disintegration concentration of 3.5% to 4.5%, an outlet concentration of 3.0% to 3.5%, and a rotor flushing water pressure of 240 kPa. The inlet concentration of the high-concentration cleaner is 2.5% to 3.5%, the fine pulp concentration is 2.5% to 3.2%, the inlet pressure is 250 to 400 kPa, and the pressure drop is 172 kPa. The coarse screen uses a two-stage coarse screen, in which the first stage coarse screen has a screen gap of 0.6-0.8 MM, the second stage coarse screen has an aperture of 1.6-1.8 MM, and the inlet concentration is 2.0-3.0%. The inlet concentration of the grading screen is 1.5-2.2%, and the screen gap is 0.15-0.17 mm. During the thermal dispersion treatment, the temperature is 90 to 105 ° C, the back pressure is 100 to 160 KPa, and the energy consumption is 35 to 100 kw / t.

[0026] The high-long mixed pulp formed by mixing long fiber pulp with high card pulp adopts three disc refiners in series for beating. Among them, the first disc refiner adopts high-intensity beating, using a cutting-type grinding disc, and the pulping intensity is 3.0-4.5J / m, which can open the cell wall of the fiber, improve the fibrillation effect, and effectively improve the beating degree. The second disc refiner adopts medium-high intensity beating, and its pulping intensity is 2.5-3.0J / m; the appropriate medium-high refining intensity is conducive to the pulp after the first disc refiner to obtain appropriate refining effect, and then the fiber obtains better external fibrillation effect, while avoiding excessive shearing of the fiber, effectively improving the tensile strength of the paper, and at the same time the beating degree is partially improved. The third disc refiner adopts medium intensity beating: the pulping intensity is 2.0-2.5J / m; the relatively low intensity in the third disc refiner is more appropriate. Appropriate refining intensity is conducive to a softer refining effect on the pulp with shorter fibers after two refinings, so that the fibers can be better internally and externally fiberized, effectively improving the cohesion and tensile strength of the paper.

[0027] The medium fiber pulp is pulped by a disc grinder with medium intensity: the pulping intensity is 2.0-2.5J / m; the high-short mixed pulp formed by mixing the short fiber pulp with the high card pulp is pulped by a disc grinder with medium intensity: the pulping intensity is 2.0-2.5J / m; due to the short fiber and medium fiber length, the main use of medium and low beating intensity grinding discs, use the filament broom type grinding disc to reduce fiber cutting.

[0028] All the above-mentioned disc grinders use stainless steel ND90 grinding discs. DN90 is made of stainless steel and has excellent anti-tooth breakage performance and good wear resistance. Compared with ordinary stainless steel, ND90 has a higher surface hardness, ensuring that its grinding teeth remain sharp throughout the life of the grinding disc, maintaining the stability of the grinding quality and power, especially in the later stage of the grinding disc; at the same time, the use of DN90 grinding discs can extend the service life of the grinding discs and meet the needs of production quality and output.

[0029] The above-mentioned disc grinding and beating process can improve the service life of the disc grinding disc and the fiber beating effect. By selecting the material and tooth shape of the grinding disc, the service life of the grinding disc is increased by about 20-30%, and the beating effect is improved by about 15-20%.

[0030] The pulping process requirements for each grinding disc are as follows: the pulping concentration of long fiber pulp is 4-6%, and the beating degree is 25-30°SR; the pulping concentration of medium fiber pulp is 4-6%, and the beating degree is 30-35°SR; the pulping concentration of short fiber pulp is 4-6%, and the beating degree is 35-45°SR; the beating degree of high card pulp is 30-35°SR; the pulping concentration of natural wood pulp is 4-5%, and the beating degree is 30-40°SR.

[0031] In step S003, the specific preparation process of high card pulp is as follows: after the wood chip raw material is washed and pre-soaked, it is boiled in a digester to dissolve the lignin in the wood chip raw material, so that the fibers in the wood chip raw material are separated from each other into pulp, and the pulp is then beaten by medium-consistency grinding to fibrillate the wood chip fibers and dissociate them into single fibers and fiber bundles, and then the large fiber bundles, sand particles and metal particle impurities are removed by screening and purification equipment, and finally the cleanliness and concentration of the pulp are improved by washing and concentration to prepare high card pulp that meets the quality requirements and store it in a pulp tower. In step S003, the proportion of high card pulp in high-long mixed pulp is 0-30%; the proportion of high card pulp in high-short mixed pulp is 0-30%. Among them, the wood chip raw material is eucalyptus / acacia / pine. The screening and purification equipment includes a vacuum pulp washer and a double-roll pulp washer connected in sequence.

[0032] The specific preparation process requirements of high card pulp are shown in the table below.

[0033]

[0034]

[0035] In step S003, the prepared high card pulp, imported waste paper, and domestic waste are beaten to the same beating degree 30°SR and the bursting strength is measured by sheet making. The conclusion is: the bursting strength of high card pulp is 3.84 Kpa.㎡ / g, the bursting strength of imported waste paper is 2.78 Kpa.㎡ / g, and the bursting strength of domestic waste is 1.8 Kpa.㎡ / g, that is, the bursting strength of high card pulp is 38% higher than that of imported waste paper, and 113% higher than that of domestic waste.

[0036] The experimental data of high card pulp beating alone are as follows:

[0037]

[0038] The conclusion is: when the high-calorie pulp is beaten to 40°SR, the folding endurance is the highest, and the folding endurance increases from 7 times to 165 times, an increase of 22 times; when the high-calorie pulp is beaten to 50°SR, the breaking length, tensile index and bursting resistance are the highest, among which the bursting resistance increases from 2.99Kpa.㎡ / g to 4.5Kpa.㎡ / g, an increase of 50.5%.

[0039] The experimental data of mixing high card pulp with long fiber pulp and short fiber pulp are as follows:

[0040]

[0041]

[0042] The conclusion is: when the short fiber pulp and high card pulp are mixed and beaten to 40°SR, the folding resistance is the highest, and the folding resistance increases from 7 times to 32 times, an increase of 3.5 times; when the pulp is beaten to 50°SR, the breaking length, tensile index and burst resistance are the highest, among which the burst resistance increases from 2.39Kpa.㎡ / g to 3.54Kpa.㎡ / g, an increase of 48%;

[0043] When long fiber pulp and high card pulp are mixed and beaten to 50°SR, the breaking length, tensile index, tear resistance and folding resistance are the highest, among which the tear resistance is increased from 2.31Kpa.㎡ / g to 3.93Kpa.㎡ / g, an increase of 70%.

[0044] In step S002, the specific preparation process of natural wood pulp is as follows: purchase natural wood pulp finished raw materials, send them to the hydraulic pulper through a pulp chain conveyor, the hydraulic pulper pulps the finished wood pulp raw materials, and the concentration of the pulp after pulping is controlled at about 4-5%, and then send them to the wood pulp front pool, pump them to the wood pulp disc for beating, and enter the post-beating pool after beating, wherein the wood pulp disc is connected in series by three discs, the first disc adopts high-intensity beating, uses a cutting-type grinding disc, and the pulping intensity is 3.0-4.5J / m; the second disc adopts medium-high intensity beating, and its pulping intensity is 2.5-3.0J / m; the third disc adopts medium intensity beating: the pulping intensity is 2.0-2.5J / m.

[0045] In step S004, the natural wood pulp and medium fiber pulp are put into the mixed pulp pool of the surface layer paper machine, and are further screened by pumping to the flow desander and pressure screen. After the impurities are removed, they enter the surface layer headbox, and are sent to the surface layer wire section after passing through the surface layer headbox; the high-long mixed pulp, medium fiber pulp and high-short mixed pulp are put into the mixed pulp pool of the core layer paper machine, and are further screened by pumping to the flow desander and pressure screen. After the impurities are removed, they enter the core layer headbox, and are sent to the core layer wire section after passing through the core layer headbox; the high-long mixed pulp and high-short mixed pulp are put into the mixed pulp pool of the bottom layer paper machine, and are further screened by pumping to the flow desander and pressure screen. After the impurities are removed, they enter the bottom layer headbox, and are sent to the bottom layer wire section after passing through the bottom layer headbox.

[0046] The surface layer, core layer and bottom layer pulp are dehydrated and formed into a wet paper web through the wire part, which means that the wire part has four layers of wires, namely the surface layer wire part, the core layer wire part, the bottom layer wire part and the dehydration wire part. The dehydration wire mainly dehydrates the bottom layer pulp, so that the surface layer, core layer and bottom layer pulp are dehydrated and formed into a wet paper web through the wire part.

[0047] When producing 160-250g high-end packaging paper, the surface layer is 25-55g / m2, the core layer is 30-65g / m2, and the bottom layer is 80-150g / m2, among which, the weight percentage of the surface layer pulp is: 20-50% natural wood pulp, 50-80% medium fiber pulp; the weight percentage of the core layer pulp is: 20-50% high-long mixed pulp, 3-30% medium fiber pulp, 50-80% high-short mixed pulp; the weight percentage of the bottom layer pulp is: 30-70% high-long mixed pulp, 30-60% high-short mixed pulp.

[0048] In step S004, when the paper web passes through the pressing part for extrusion and dehydration, the pressing part adopts three-line pressing, wherein the first line pressing pressure is 700-780kn / m, the second line pressing pressure is 1000-1200kn / m, and the third line pressing pressure is 35-45kn / m; after passing through the pressing part, the paper web enters the front drying part for drying, and the paper web passing through the front drying part is glued by the glue applicator, and a layer of glue for improving the surface strength of the finished paper is applied on the surface of the paper web, wherein the glue applicator adopts an immersion type Gluing is done by scraping the back surface with glue; after gluing, the paper web enters the post-drying section for drying, and the moisture content of the finished paper is controlled within the range of 8.0-9.0% by drying; the dried paper web enters the next section for calendering, and the paper web passes through the calender heated roller under a certain pressure to press the paper sheet to make the thickness of the paper sheet uniform and improve the smoothness and glossiness of the paper sheet. The calender adopts two-stage heated rollers for linear pressing, and finally reaches the reel after calendering to be made into high-grade packaging paper.

[0049] Specifically, when producing 160g high-end packaging paper, the surface layer is 25g / m2, the core layer is 34g / m2, and the bottom layer is 101g / m2. The surface layer pulp weight percentage is: 20% natural wood pulp, 80% medium fiber pulp; the core layer pulp weight percentage is: 31% high-long mixed pulp, 5.6% medium fiber pulp, 63.4% high-short mixed pulp; the bottom layer pulp weight percentage is: 45% high-long mixed pulp, 55% high-short mixed pulp. See the table below for details:

[0050]

[0051] The production process of rubber compound preparation is as follows:

[0052]

[0053]

[0054] A dry strength agent is also added to the surface layer slurry, the core layer slurry and the bottom layer slurry, wherein the addition amount of the dry strength agent is 10-35KG / T; the main component of the dry strength agent is polyacrylamide macromolecular polymer, which forms hydrogen bonds with the fiber to improve the strength of the paper; a reinforcing agent is also added to the core layer slurry / bottom layer slurry, wherein the addition amount of the reinforcing agent is 0-15KG / T; slurry starch is also added to the surface layer slurry and the core layer slurry, wherein the addition amount of the slurry starch is 3-10KG / T; the slurry starch is prepared by steaming amphoteric starch, the main component of amphoteric starch is prepared by modification of cassava starch, and the starch molecules have both anionic and cationic reaction groups of starch. Since the fiber is negatively charged, it is easy to adsorb the cationic groups of the amphoteric starch, so that the fibers are combined to increase the strength of the paper. The main component of the enhancer is a high molecular polymer with polyacrylamide as the main body, which has a relatively high charge density, a moderate molecular weight and a high molecular structure. It can effectively promote the contact and hydroxyl combination between fibers, promote the retention and enhancement efficiency of the dry strength agent, improve the retention of fine fibers and anionic waste, form a good floc structure between fibers, promote the filtration of pulp in the mesh, and tightly combine with fibers through ionic bonds to form a relatively uniform cross-linking network, thereby improving the strength and bonding force of paper.

[0055] In summary, the present invention uses high card pulp to replace imported waste paper pulp, mixes it with waste paper for pulping, and forms high-end packaging paper. Compared with the prior art, the present invention uses high card pulp to replace the imported waste paper pulp originally used, and the amount of natural wood pulp used is reduced by 15-20%, and the amount of domestic waste is increased by 10-15%, which not only reduces the production cost of high-end packaging paper, but also solves the problem of shortage of imported waste paper raw materials. In addition, the bursting strength of the self-made high card pulp of the present invention is higher than that of imported waste paper (U.S. waste), and the strength is higher than that of domestic waste, so that the bursting resistance, folding index, ring pressure index and other indicators of the high-end packaging paper manufactured by the present invention are at a high level, which improves the quality of the finished paper and can meet the quality requirements of customers. Furthermore, the process of making the self-made high card pulp of the present invention is also relatively simple, scientific and reasonable. In addition, the present invention improves the service life of the disc grinding plate and the fiber beating effect. By selecting the material and tooth shape of the grinding plate, the service life of the grinding plate is increased by about 20-30%, and the beating effect is increased by about 15-20%.

[0056] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes or modifications made according to the structure, characteristics and principles described in the patent application scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A method for making high-grade packaging paper by mixing high card pulp and waste paper, characterized in that: The following steps are involved: S001: Preparation of OCC waste paper pulp: Domestic waste OCC is sequentially crushed, deslagging, coarsely screened, and graded to form long fiber pulp, medium fiber pulp, and short fiber pulp. The long fiber pulp from the graded screen is sequentially passed through a deslagging device, a fine screen, a multi-disc thickener, hot dispersion, a long fiber tapping fore-tank, and a disc grinder before entering a long fiber tapping post-tank; the medium fiber pulp from the graded screen is sequentially passed through a medium fiber deslagging device, a fine screen, a multi-disc thickener, hot dispersion, a medium fiber tapping fore-tank, and a disc grinder before entering a medium fiber tapping post-tank; the long fiber pulp from the graded screen is sequentially passed through a medium fiber deslagging device, a fine screen, a multi-disc thickener, hot dispersion, a short fiber tapping fore-tank, and a disc grinder before entering a short fiber tapping post-tank; S002: Preparation of natural wood pulp: The purchased commercial wood pulp raw material is crushed by a hydraulic pulper, and then the pulp is beaten by a disc grinder and then enters the post-beating pool to prepare the natural wood pulp; wherein, the specific preparation process of the natural wood pulp is as follows: the finished product raw material of the commercial natural wood pulp is purchased, and sent to the hydraulic pulper through a wood pulp chain conveyor, and the hydraulic pulper pulps the finished wood pulp raw material, and the concentration of the crushed wood pulp is controlled at about 4-5%, and then sent to the wood pulp front-beating pool, and is pumped to the wood pulp disc grinder for beating, and then enters the post-beating pool after beating, wherein the wood pulp disc grinder is connected in series by three disc grinders, the first disc grinder adopts high-intensity beating, uses a cutting-type grinding disc, and the pulping intensity is 3.0-4.5J / m; the second disc grinder adopts medium-high intensity beating, and its pulping intensity is 2.5-3.0J / m; the third disc grinder adopts medium-intensity beating: the pulping intensity is 2.0-2.5J / m; S003: Preparation of high card pulp: The wood chips are washed and pre-soaked → cooked → medium-consistency milled → screened and purified → washed and concentrated to form high card pulp, which is then stored in a pulp tower. The high card pulp is first pulped through a low-consistency disc mill and added to the long fiber tapping pool and the short fiber tapping pool in step S001. The high card pulp and long fiber pulp are mixed and beaten to form a high-long mixed pulp which enters the long fiber tapping pool; the high card pulp and short fiber pulp are mixed and beaten to form a high-short mixed pulp which enters the short fiber tapping pool: Among them, the specific preparation process of high card pulp The wood chip raw material is washed and pre-soaked, and then boiled in a digester to dissolve the lignin in the wood chip raw material, so that the fibers in the wood chip raw material are separated from each other into pulp. The pulp is then beaten by medium-consistency grinding to fibrillate the wood chip fibers and dissociate them into single fibers and fiber bundles. The large fiber bundles, sand particles and metal particle impurities are then removed by screening and purification equipment. Finally, the cleanliness and concentration of the pulp are increased by washing and concentration to prepare high-cardia pulp that meets quality requirements and is stored in a pulp tower. S004: Paper machine production: natural wood pulp and medium fiber pulp are put into the mixed pulp pool of the surface paper machine, and after impurities are removed, they are sent to the surface layer wire section through the surface layer headbox; high long mixed pulp, medium fiber pulp and high short mixed pulp are put into the mixed pulp pool of the core paper machine, and after impurities are removed, they are sent to the core layer wire section through the core layer headbox; high long mixed pulp and high short mixed pulp are put into the mixed pulp pool of the bottom paper machine, and after impurities are removed, they are sent to the bottom layer wire section through the bottom layer headbox; the surface layer, core layer and bottom layer pulps are dehydrated and formed through the wire section to form a wet paper web, and the three layers of pulp are compounded together, and then go through the press section → pre-drying → sizing → post-drying → calendering → winding to make high-grade packaging paper; In step S003, the proportion of high-sticking pulp in the high-long mixed pulp is 26-30%; the proportion of high-sticking pulp in the high-short mixed pulp is 23-30%; In step S004, when producing 160-250g high-grade packaging paper, the surface layer weight is 25-55g / m 2 The core layer is 30-65g / m 2 The base material is 80-150g / m 2 , among which, the weight percentage of surface pulp: natural wood pulp 20-50%, medium fiber pulp 50-80%; the weight percentage of core pulp: high-long mixed pulp 20-50%, medium fiber pulp 3-30%, high-short mixed pulp 50-80%; the weight percentage of bottom pulp: high-long mixed pulp 30-70%, high-short mixed pulp 30-60%; In step S004, when the paper web is squeezed and dehydrated by the pressing part, the pressing part adopts three-line pressing, wherein the first pressing line pressure is 700-780 kN / m, the second pressing line pressure is 1000-1200 kN / m, the three-line pressure is 35-45kN / m; after the paper web passes through the press section, it enters the front drying section for drying. After the paper web passes through the front drying section, it is glued by the sizing machine, and a layer of glue is applied on the surface of the paper web to improve the surface strength of the finished paper. Among them, the sizing machine uses immersion glue to apply glue on the front surface and scraper glue on the back surface; after glue application, the paper web enters the rear drying section for drying, and the moisture content of the finished paper is controlled within the range of 8.0-9.0% by drying; the dried paper web enters the next section for calendering, and the paper web passes through the heating roller of the calender under a certain pressure to press the paper sheet to make the thickness of the paper sheet uniform and improve the smoothness and glossiness of the paper sheet. Among them, the calender uses two-stage heating rollers for line pressing, and finally reaches the winding after calendering treatment to be made into high-grade packaging paper; A dry strength agent is also added to the surface layer slurry, the core layer slurry and the bottom layer slurry, wherein the addition amount of the dry strength agent is 10-35kg / T; the main component of the dry strength agent is polyacrylamide macromolecular polymer, which forms hydrogen bonds with the fibers to improve the strength of the paper; a reinforcing agent is also added to the core layer slurry / bottom layer slurry, wherein the addition amount of the reinforcing agent is 0-15kg / T; slurry starch is also added to the surface layer slurry and the core layer slurry, wherein the addition amount of the slurry starch is 3-10kg / T; the slurry starch is prepared by steaming amphoteric starch, the main component of amphoteric starch is prepared by modification of cassava starch, and the starch molecules have both anionic and cationic reaction groups of starch. Since the fibers are negatively charged, they are easily adsorbed by the cationic groups of the amphoteric starch, so that the fibers are combined to increase the strength of the paper.

2. The method for making high-grade packaging paper by mixing high card pulp and waste paper according to claim 1, characterized in that: In step S003, the prepared high card pulp, imported waste paper, and domestic waste are beaten to the same beating degree of 30ºSR and the bursting strength is measured by sheeting. The bursting strength of high card pulp is 3.84 kpa.㎡ / g, the bursting strength of imported waste paper is 2.78 kpa.㎡ / g, and the bursting strength of domestic waste is 1.8 kpa.㎡ / g, that is, the bursting strength of high card pulp is 38% higher than that of imported waste paper, and 113% higher than that of domestic waste.

3. The method for making high-grade packaging paper by mixing high card pulp and waste paper according to any one of claims 1-2, characterized in that: In step S001, the specific preparation process of OCC waste paper pulp is as follows: domestic waste OCC raw materials are transported to the hydraulic pulper through the waste paper chain conveyor, and the hydraulic pulper crushes the domestic waste OCC raw materials, and then pass through the high-concentration cleaner, which separates metal and glass impurities in the pulp, and then pass through the coarse screen, the grading screen, the low-concentration cleaner, and the fine screen to further remove impurities in the pulp, wherein the grading screen classifies the pulp into long-fiber pulp, medium-fiber pulp, and short-fiber pulp according to different fiber sizes, and each level of pulp is respectively passed through the concentrator to remove part of the water in the pulp, and after the concentration is increased, it enters the thermal dispersion equipment for treatment, and the thermal dispersion equipment disperses the hot melt in each level of pulp into particles invisible to the naked eye through the action of high temperature and mechanical force, so as to improve the appearance quality of the finished paper, and then the pulp of each level is beaten by the disc grinding and enters the respective post-beating pool.

4. The method for making high-grade packaging paper by mixing high card pulp and waste paper according to claim 3, characterized in that: The high-long mixed pulp formed by mixing long fiber pulp with high card pulp is beaten by three disc refiners in series, among which the first disc refiner adopts high-intensity beating, uses a cutting-type grinding disc, and the grinding intensity is 3.0-4.5J / m; the second disc refiner adopts medium-high intensity beating, and its grinding intensity is 2.5-3.0J / m; the third disc refiner adopts medium intensity beating: the grinding intensity is 2.0-2.5J / m; the medium fiber pulp is beaten by one disc refiner, which adopts medium intensity beating: the grinding intensity is 2.0-2.5J / m; the high-short mixed pulp formed by mixing short fiber pulp with high card pulp is beaten by one disc refiner, which adopts medium intensity beating: the grinding intensity is 2.0-2.5J / m; all the above disc refiners use stainless steel ND90 grinding discs.

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