Production process of high-water-resistance moisture-proof three-layer composite craft paper

Abstract

The invention discloses a production process of high-water-resistance and moisture-proof three-layer composite craft paper, and relates to the technical field of pulping and papermaking. Compounding the fiber surface layer, the fiber core layer and the fiber bottom layer, performing two-step shoe squeezing for physical dehydration, and performing steam drying in a drying area after squeezing dehydration to form a fiber layer; a proper amount of glue is added into 100% enzymatic conversion corn starch, a surface sizing layer and a bottom sizing layer are formed respectively, a fiber layer is fed into a sizing area, the surface sizing layer and the bottom sizing layer are smeared to the two side faces of the fiber layer, drying is conducted again through steam, finally surface modification is conducted through hard calendering, the thickness can be controlled, and the surface sizing layer and the bottom sizing layer are obtained. The packaging base paper is obtained, the kraft liner paper with national waste raw materials as the core bottom layer is obtained, the paper can be applied to complex application environments such as low temperature and high humidity by adding the water-resistant functional material, the strength attenuation amplitude of the finished paper is small, and the good folding and explosion resistance of the paper is kept.

Description

Technical Field

[0001] The present invention relates to the technical field of pulp and paper making, and particularly relates to a production process of a three-layer composite kraft paper with high water resistance and moisture resistance. Background Art

[0002] Kraft paper is widely used in the domestic packaging industry, covering multiple fields such as food, electronics, daily chemicals, and household appliances. In the packaging of electronic products, kraft paper effectively protects precision products such as mobile phones and computers with certain buffering performance and high strength. With the rapid development of e-commerce, the demand for paper packaging products in the e-commerce field is also increasing. E-commerce enterprises are increasingly paying attention to the quality and environmental protection of packaging, and paper packaging products are favored by e-commerce platforms and consumers due to their environmental protection characteristics and customization advantages. Summary of the Invention

[0003] The purpose of the present invention is to provide a production process of a three-layer composite kraft paper with reasonable design and convenient use for the defects and deficiencies of the existing technology. The kraft paper uses national waste raw materials as the core bottom layer, and through the addition of water-resistant functional materials, the paper type can be applied to complex application environments such as low temperature and high humidity, with a small attenuation amplitude of the paper strength and maintaining good anti-fold explosion ability.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: It includes the following steps:

[0005] Step 1: Fiber layer forming:

[0006] Step 1-1: Grind the surface layer base material by mixing and feeding in proportion, and uniformly add it to the pulp mixing tank; then add the anti-counterfeiting dye to the pulp mixing tank in proportion to control the a value of the paper color phase at 9.0 ± 0.5 and the b value at 22.0 ± 1.0. Finally, add the sizing agent, emulsifier, and binary process aid to the wire for forming to form the fiber surface layer;

[0007] Step 1-2: Add the core layer base material to the pulp mixing tank in proportion, and then add the self-made strengthening agent, sizing agent, and emulsifier in proportion in sequence to facilitate the control of the wire concentration. Finally, add the ternary process aid to control the retention rate at the wire part, and form the fiber core layer by forming on the wire;

[0008] Step 1-3: Uniformly add the bottom layer base material to the bottom pulp mixing tank in proportion, and then add the self-made strengthening agent, sizing agent, and emulsifier in proportion in sequence to form the fiber bottom layer;

[0009] Step 1-4: Composite the fiber surface layer obtained in Step 1-1, the fiber core layer obtained in Step 1-2, and the fiber bottom layer obtained in Step 1-3, and then enter two shoe presses for physical dehydration. After pressing and dehydration, it is dried by steam in the drying area to form the fiber layer;

[0010] Step 2: Add an appropriate amount of glue to 100% enzyme-converted corn starch to form a surface sizing layer and a bottom sizing layer respectively;

[0011] Step 3: Feed the fiber layer obtained in Steps 1-4 into the sizing area, apply the surface sizing layer and the bottom sizing layer obtained in Step 2 to both sides of the fiber layer, dry it again through steam, and finally perform surface finishing through hard calendering, with the thickness controllable, to obtain the base paper for packaging.

[0012] As a further improvement of the present invention, the fiber surface layer accounts for 18%-20% of the mass of the formed paper, the fiber core layer accounts for 55%-58% of the mass of the formed paper, and the fiber bottom layer accounts for 20%-22% of the mass of the formed paper.

[0013] As a further improvement of the present invention, the components of the ternary process aid include liquid, solid, and bentonite.

[0014] As a further improvement of the present invention, the dryness of the fiber layer after lamination is 18%-22%.

[0015] As a further improvement of the present invention, the nip pressure value of the fiber layer is 900-1200 kn / m, and the nip pressure value of the sized paper is 50-60 kn / m.

[0016] As a further improvement of the present invention, the surface sizing layer and the bottom sizing layer account for 1%-3% of the mass of the formed paper, and the sizing amount per square in the surface sizing layer and the bottom sizing layer is 2-3 g.

[0017] As a further improvement of the present invention, the proportion of the self-made reinforcing agent in the fiber surface layer, fiber core layer, and fiber bottom layer is 1%-2%, the proportion of the sizing agent is 0.2%-0.3%, and the proportion of the emulsifier is 0.2%-0.3%.

[0018] As a further improvement of the present invention, the proportion of the anti-counterfeiting dye is 3%-5%, and the components of the anti-counterfeiting dye include cationic yellow dye, cationic red dye, and black dye, wherein the cationic yellow dye accounts for 65%-70%, the cationic red dye accounts for 20%-25%, and the black dye accounts for 5%-15%.

[0019] As a further improvement of the present invention, the components of the binary process aid include liquid and solid.

[0020] As a further improvement of the present invention, the surface layer base material adopts 70%-80% NUKP / 20%-30% LUKP, and the core layer base material and the bottom layer base material are both made of 98% national waste through classification, screening, and purification.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The surface layer / core layer / bottom layer are formed by step-by-step slurry preparation, accurately controlling the proportion of each layer (surface layer 18-20%, core layer 55-58%, bottom layer 20-22%) and the addition of additives, improving the structural stability of the paper;

[0023] 2. The combination of double-shoe pressing (linear pressure 900-1200 kN / m) and steam drying is adopted to make the dryness of the fiber layer reach 18-22%, enhancing the physical properties;

[0024] 3. 3-5% of customized dyes (yellow / red / black compound) are added to the surface layer, accurately regulating the hue (a value 9.0±0.5, b value 22.0±1.0), achieving high-recognizability anti-counterfeiting;

[0025] 4. Enzyme-converted corn starch glue (1-3% of the paper quality, 2-3 g / m 2 ) is combined with hard calendering (linear pressure 50-60 kN / m) to improve the surface strength and thickness uniformity. Detailed implementation manners

[0026] Example 1:

[0027] The technical solution adopted in this example is as follows: It includes the following steps:

[0028] Step 1: Fiber layer forming:

[0029] Step 1-1: Grind the surface layer base material composed of 70% NUKP and 30% LUKP by means of mixed feeding, uniformly add it to the sizing tank, and the proportion of the surface layer base material is 13.3%; then add the anti-counterfeiting dye composed of 65% cationic yellow dye, 25% cationic red dye and 10% black dye into the sizing tank, and the proportion of the anti-counterfeiting dye is 3%, which can control the a value of the paper color to be 9.0±0.5 and the b value to be 22.0±1.0. Finally, add 0.25% sizing agent, 0.25% emulsifier and 1.2% binary process aid to form a fiber surface layer on the wire, and the fiber surface layer accounts for 18% of the paper quality;

[0030] Step 1-2: Add the core layer base material purified by grading and screening 98% of national waste paper into the sizing tank, and the proportion of the core layer base material is 53.25%. Then add 1% self-made strengthening agent, 1% sizing agent and 0.25% emulsifier in proportion to facilitate the control of the on-wire concentration. Finally, add 1.5% ternary process aid. The components of the ternary process aid include liquid, solid and bentonite to control the retention rate in the wire part, and form a fiber core layer on the wire. The fiber core layer accounts for 57% of the paper quality;

[0031] Step 1-3: Uniformly add the bottom substrate, which is made from 98% national waste through classification, screening, and purification, into the bottom sizing pulp tank. The proportion of the bottom substrate is 18.75. Then, sequentially add 1% self-made strengthening agent, 1% sizing agent, and 0.25% emulsifier in proportion to form a fiber bottom layer, which accounts for 21% of the weight of the finished paper.

[0032] Step 1-4: Composite the fiber surface layer obtained in Step 1-1, the fiber core layer obtained in Step 1-2, and the fiber bottom layer obtained in Step 1-3, and then enter two shoe presses for physical dehydration. Before pressing, the dryness of the fiber layer is 18%. After pressing with a pressure of 900 kn / m, the dryness of the fiber layer is 42%. After pressing and dehydration, it is then dried by steam in the drying zone to form a fiber layer.

[0033] Step 2: Add glue with a sizing amount of 1.5 g per square meter to 100% enzyme-converted corn starch to form a surface sizing layer and a bottom sizing layer respectively. Both the surface sizing layer and the bottom sizing layer each account for 2% of the weight of the finished paper.

[0034] Step 3: Send the fiber layer obtained in Step 1-4 into the sizing area, and apply the surface sizing layer and the bottom sizing layer obtained in Step 2 to both sides of the fiber layer. Then, dry it again by steam, and finally perform surface modification through hard calendering. The thickness can be controlled to obtain the packaging base paper.

[0035] Compared with the prior art, the beneficial effects of this specific embodiment are as follows:

[0036] 1. The surface layer / core layer / bottom layer are sized and formed step by step, accurately controlling the proportion of each layer (surface layer 18-20%, core layer 55-58%, bottom layer 20-22%) and the addition of additives, improving the structural stability of the paper.

[0037] 2. The combination of double shoe presses (linear pressure 900-1200 kN / m) and steam drying is adopted to make the dryness of the fiber layer reach 18-22%, enhancing the physical properties.

[0038] 3. Add 3-5% customized dyes (yellow / red / black compound) to the surface layer, accurately regulating the hue (a value 9.0±0.5, b value 22.0±1.0) to achieve high-identification anti-counterfeiting.

[0039] 4. Enzyme-converted corn starch glue (1-3% of the weight of the finished paper, 2-3 g / m 2 ) combined with hard calendering (linear pressure 50-60 kN / m) to improve the surface strength and thickness uniformity.

[0040] Example 2:

[0041] The technical solution adopted in this example is as follows: It includes the following steps:

[0042] Step 1: Fiber layer forming:

[0043] Step 1-1: Grind the surface layer base material composed of 70% NUKP and 30% LUKP by mixing and feeding, and evenly add it to the sizing chest. The surface layer base material accounts for 13.56%. Then add the anti-counterfeiting dye composed of 65% cationic yellow dye, 25% cationic red dye, and 10% black dye to the sizing chest. The anti-counterfeiting dye accounts for 4%, which can control the a value of the paper color phase within 9.0 ± 0.5 and the b value within 22.0 ± 1.0. Finally, add 0.22% sizing agent, 0.22% emulsifier, and 1.5% binary process aid onto the wire to form a fiber surface layer, and the fiber surface layer accounts for 19.5% of the finished paper quality;

[0044] Step 1-2: Add the core layer base material, which is made of 98% national waste after classification, screening, and purification, to the sizing chest. The core layer base material accounts for 53.16%. Then sequentially add 1.2% self-made strengthening agent, 0.22% sizing agent, and 0.22% emulsifier in proportion to facilitate the control of the concentration onto the wire. Finally, add 1.2% ternary process aid. The composition of the ternary process aid includes liquid, solid, and bentonite to control the retention rate at the wire section. Then form a fiber core layer onto the wire, and the fiber core layer accounts for 56% of the finished paper quality;

[0045] Step 1-3: Evenly add the bottom layer base material, which is made of 98% national waste after classification, screening, and purification, to the bottom layer sizing chest. The bottom layer base material accounts for 19.86%. Then sequentially add 1.2% self-made strengthening agent, 0.22% sizing agent, and 0.22% emulsifier in proportion to form a fiber bottom layer, and the fiber bottom layer accounts for 21.5% of the finished paper quality;

[0046] Step 1-4: Composite the fiber surface layer obtained in Step 1-1, the fiber core layer obtained in Step 1-2, and the fiber bottom layer obtained in Step 1-3, and then enter two shoe presses for physical dehydration. Before pressing, the dryness of the fiber layer is 20%. After pressing with a pressure of 1000 kn / m, the dryness of the fiber layer is 44%. After pressing and dehydration, it is then dried by steam in the drying zone to form a fiber layer;

[0047] Step 2: Add glue with a sizing amount of 2 g per square meter to 100% enzyme-converted corn starch to form a surface layer sizing layer and a bottom layer sizing layer respectively. Both the surface layer sizing layer and the bottom layer sizing layer each account for 1.5% of the finished paper quality;

[0048] Step 3: Feed the fiber layer obtained in Step 1-4 into the sizing area, and apply the surface layer sizing layer and the bottom layer sizing layer obtained in Step 2 to both sides of the fiber layer. Then dry it again by steam, and finally perform surface modification through hard calendering to control the thickness and obtain the packaging base paper.

[0049] Example 3:

[0050] The technical solution adopted in this embodiment is as follows: It includes the following steps:

[0051] Step 1: Fiber layer forming:

[0052] Step 1-1: Grind the surface layer base material composed of 70% NUKP and 30% LUKP by means of mixing and feeding, uniformly add it to the pulp mixing tank, and the surface layer base material accounts for 12.24%; then add the anti-counterfeiting dye composed of 65% cationic yellow dye, 25% cationic red dye and 10% black dye into the pulp mixing tank, and the anti-counterfeiting dye accounts for 5%, which can control the a value of the paper color phase to be 9.0±0.5 and the b value to be 22.0±1.0. Finally, add 0.28% sizing agent, 0.28% emulsifier, and 1% binary process aid to form a fiber surface layer through wire forming, and the fiber surface layer accounts for 18.8% of the finished paper quality;

[0053] Step 1-2: Add the core layer base material purified by grading, screening and purification of 98% national waste paper into the pulp mixing tank, and the core layer base material accounts for 50.84%. Then add 1.8% self-made strengthening agent, 0.28% sizing agent, and 0.28% emulsifier in proportion to facilitate the control of the wire forming concentration. Finally, add 1.8% ternary process aid. The components of the ternary process aid include liquid, solid and bentonite to control the retention rate in the wire section, and form a fiber core layer through wire forming. The fiber core layer accounts for 55% of the finished paper quality;

[0054] Step 1-3: Uniformly add the bottom layer base material purified by grading, screening and purification of 98% national waste paper into the bottom layer pulp mixing tank. The bottom layer base material accounts for 18.14, and then add 1.8% self-made strengthening agent, 0.28% sizing agent and 0.28% emulsifier in proportion to form a fiber bottom layer. The fiber bottom layer accounts for 20.5% of the finished paper quality;

[0055] Step 1-4: Composite the fiber surface layer obtained in Step 1-1, the fiber core layer obtained in Step 1-2, and the fiber bottom layer obtained in Step 1-3, and then enter two shoe presses for physical dehydration. Before pressing, the dryness of the fiber layer is 22%. After pressing with a pressure of 1100 kn / m, the dryness of the fiber layer is 46%. After pressing and dehydration, it is dried by steam in the drying zone to form a fiber layer;

[0056] Step 2: Add glue with a sizing amount of 2.8 g per square meter to 100% enzyme-converted corn starch to form a surface layer sizing layer and a bottom layer sizing layer respectively. The surface layer sizing layer and the bottom layer sizing layer each account for 2.85% of the finished paper quality;

[0057] Step 3: Send the fiber layer obtained in Step 1-4 into the sizing area, and apply the surface layer sizing layer and the bottom layer sizing layer obtained in Step 2 to both sides of the fiber layer, and then dry it again by steam. Finally, perform surface modification through hard calendering, and the thickness can be controlled to obtain the packaging base paper.

[0058] For those skilled in the art, they can modify the technical solutions described in the foregoing embodiments and perform equivalent replacements of some technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A highly water-resistant and moisture-proof three-layer composite kraft paper production process, characterized by: It contains the following steps: Step (1): Fiber layer forming: Step (1-1): grinding the surface layer substrate by mixing and feeding in proportion, and evenly adding it into the pulping tank; then adding the anti-counterfeiting dye into the pulping tank in proportion, so as to control the a value of the paper surface color to be 9.0±0.5 and the b value to be 22.0±1.0; finally, applying the sizing agent, emulsifier, and binary process auxiliary agent on the screen in proportion to form a fiber surface layer; Step (1-2): adding the core layer substrate into the pulp preparation tank in proportion, and then adding the homemade reinforcing agent, sizing agent, and emulsifier in proportion in order to control the concentration of the web, and finally adding the ternary process additive to control the web retention rate, and forming the fiber core layer on the web; Step (1-3): uniformly adding the bottom substrate into the bottom slurry preparation tank according to a certain proportion, and then sequentially adding a self-made reinforcing agent, a sizing agent and an emulsifier according to a certain proportion to form a fiber bottom layer; Step (1-4): the fiber surface layer obtained in step (1-1), the fiber core layer obtained in step (1-2), and the fiber bottom layer obtained in step (1-3) are compounded and then put into two shoe presses for physical dehydration. After dehydration by pressing, the fiber is then steam dried in a drying zone to form a fiber layer. Step (2): adding an appropriate amount of glue into 100% enzyme-converted corn starch to form a surface glue layer and a bottom glue layer respectively; Step (3): The fiber layer obtained in steps (1-4) is sent to the gluing area, and the surface gluing layer and the bottom gluing layer obtained in step (2) are applied to both sides of the fiber layer, dried again by steam, and finally surface modified by hard calendering. The thickness can be controlled to obtain packaging base paper.

2. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The fiber surface layer accounts for 18%-20% of the paper mass, the fiber core layer accounts for 55%-58% of the paper mass, and the fiber bottom layer accounts for 20%-22% of the paper mass.

3. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The components of the ternary process additive include liquid, solid and bentonite, and the ternary process additive accounts for 1%-2%.

4. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The dryness of the fiber layer after compounding is 18%-22%, and the dryness of the fiber layer after squeezing and dehydration is 42%-48%.

5. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The pressure value of the line pressure of the fiber layer is 900-1200 kn / m, and the pressure value of the line pressure used for the paper after sizing is 50-60 kn / m.

6. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The surface sizing layer and the bottom sizing layer account for 1%-3% of the paper mass, and the amount of sizing per square meter in the surface sizing layer and the bottom sizing layer is 2-3g.

7. The highly water-resistant and moisture-proof three-layer composite kraft paper production process according to claim 1, characterized in that: The proportion of the self-made reinforcing agent in the fiber surface layer, the fiber core layer and the fiber bottom layer is 1%-2%, the proportion of the sizing agent is 0.2%-0.3%, and the proportion of the emulsifier is 0.2%-0.3%.

8. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The anti-counterfeiting dye accounts for 3%-5%, and the components of the anti-counterfeiting dye include cationic yellow dye, cationic red dye, and black dye, among which the cationic yellow dye accounts for 65%-70%, the cationic red dye accounts for 20%-25%, and the black dye accounts for 5%-15%.

9. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The components of the binary process additive include liquid and solid, and the proportion is 1%-1.5%.

10. The production process of a highly water-resistant and moisture-proof three-layer composite kraft paper according to claim 1, characterized in that: The surface layer substrate is made of 70%-80% NUKP / 20%-30% LUKP, and the core layer substrate and the bottom layer substrate are both made of 98% domestic waste that is graded, screened and purified.