Preparation method of high-bulk cashier thermosensitive base paper

Abstract

The invention discloses a preparation method of high-bulk cashier thermosensitive base paper, which comprises the following operation steps: S1, mixing bleached softwood chemical pulp, bleached hardwood chemical pulp and bleached chemithermomechanical pulp which are beaten according to a certain proportion to form mixed pulp; s2, auxiliary materials are added into the mixed pulp to be evenly mixed, desanding is conducted through a screening system, refined pulp is diluted, and wet paper sheet manufacturing is completed on a net part; s3, the wet paper sheet enters a pressing part to be subjected to composite pressing, then enters a front-section drying cylinder to be dried, then is subjected to paper sheet surface treatment and sizing, and enters a rear-section drying cylinder to be dried after sizing surface treatment; and S4, feeding the dry paper sheet into a calendaring area, and finishing the paper sheet to obtain the paper sheet of which the paper sheet smoothness meets the requirement, namely the high-bulk cash register thermosensitive base paper. According to the preparation method of the high-bulk cash register thermosensitive body paper, the prepared high-bulk cash register thermosensitive body paper has the advantages of excellent bulk, excellent dry and wet strength, excellent surface strength, excellent color development performance, excellent image storage performance and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of papermaking process, in particular to a preparation method of high bulk cash register thermal sensitive base paper. BACKGROUND

[0002] The high bulk cash register thermal sensitive base paper is mainly used for printing transaction details of cash registers in supermarkets, shopping malls and the like after thermal sensitive coating processing. The paper has particularly high requirements for bulk, and also has relatively high requirements for dry and wet strength, surface strength, color developing performance, image preservation performance and smoothness. Compared with ordinary thermal sensitive base paper, the high bulk cash register thermal sensitive base paper has the following characteristics: 1) high bulk. In light-weight production, the high bulk can be realized at a lower paper basis weight, and the dry and wet strength, surface strength, color developing performance and image preservation performance are high, which can meet the requirements of the cash register thermal sensitive paper. This also means that the low basis weight high bulk thermal sensitive paper can replace the ordinary high basis weight thermal sensitive paper, and the profit is considerable. 2) high yield of chemi-thermo-mechanical pulp, low production cost, and realization of win-win between production enterprises and customers.

[0003] CN202211482606.4 discloses a manufacturing method of super-high bulk thermal sensitive paper. The method actually records the method for preparing the base paper, and does not give the quality technical performance indicators of the prepared base paper. It is unknown whether the base paper meets the quality requirements. Most importantly, no specific functional chemical additives are added in the preparation of the base paper. The dry and wet strength of the prepared base paper is poor, the paper is frequently broken during thermal coating processing, and the image preservation performance of the thermal sensitive paper is poor. The bulk of the prepared base paper does not meet the requirements of the thermal coating processor. At present, there is a large demand for such high bulk base paper products on the market, but the dry and wet strength and surface strength of the existing ordinary thermal sensitive base paper are low. During thermal processing, the paper is prone to breaking, and there is a serious problem of hair and powder falling. The image preservation time of thermal printing is short, the color developing performance is poor, the thermal printing clarity is not high, and the dry loss paper produced during the papermaking process produces paper pieces on the paper and AKD hydrolysis products, causing white transparent points. Therefore, how to provide a high bulk cash register thermal sensitive base paper with excellent performance is a problem that needs to be solved by those skilled in the art. SUMMARY

[0004] To solve the above technical problems, the present application provides a preparation method of high bulk cash register thermal sensitive base paper, which has the advantages of excellent bulk, dry and wet strength, surface strength, color developing performance and image preservation performance.

[0005] The technical scheme provided by the present application is as follows: A preparation method of high bulk cash register thermal sensitive base paper, comprising the following operation steps: S1, the bleached softwood chemical pulp, bleached hardwood chemical pulp and bleached chemi-mechanical pulp are respectively beaten, the bleached softwood chemical pulp, bleached hardwood chemical pulp and bleached chemi-mechanical pulp after beating are mixed in a certain proportion to form a mixed pulp; S2, the auxiliary materials are added into the mixed pulp and uniformly mixed, the uniformly mixed pulp is diluted to a concentration of 2.5-3.5%, and then the sand is removed through a screening system, the refined pulp is diluted, the pulp concentration on the wire is 0.75-0.80%, the lip opening of the headbox is controlled to be 9.5-10.0mm, and the headbox pressure head is controlled to be 230-240Kpa, so that the wet paper sheet is formed in the wire part; S3, the wet paper sheet enters the press section to be first subjected to compound pressing, the paper sheet dryness after the compound pressing is 40-45%, then the paper sheet enters the front drying cylinder to be dried until the paper sheet moisture is less than 8%, then the paper sheet surface treatment is applied, and the paper sheet enters the rear drying cylinder to be dried so that the paper sheet moisture content is maintained at 6.5-7.0%; S4, the dry paper sheet enters the calendering section to be subjected to paper finishing, the line pressure of the calendering section is 16-22N / mm, and the paper with a smoothness meeting the requirements is obtained, i.e. the high bulk thickness silver thermal sensitive base paper.

[0006] Preferably, the beating concentration of the bleached softwood chemical pulp in the step S1 is controlled to be 4.0-4.5%, and the beating beating degree is controlled to be 40±2°SR; the beating concentration of the bleached hardwood chemical pulp is controlled to be 3.5-4.0%, and the beating beating degree is controlled to be 36±2°SR; the beating concentration of the bleached chemi-mechanical pulp is controlled to be 3.5-4.0%, and the beating beating degree is controlled to be 43±2°SR.

[0007] Preferably, the bleached softwood chemical pulp, bleached hardwood chemical pulp and bleached chemi-mechanical pulp in the step S1 are configured according to the following mass percentage: the bleached softwood chemical pulp is 22-28%, the bleached hardwood chemical pulp is 10-15%, the bleached chemi-mechanical pulp is 60-65%.

[0008] Preferably, the bleached softwood chemical pulp in the step S1 is mixed pulp of larch, red pine and spruce.

[0009] Preferably, the bleached hardwood chemical pulp in the step S1 is made of poplar.

[0010] Preferably, the bleached chemi-mechanical pulp in the step S1 is made of eucalyptus.

[0011] Preferably, the components contained in the auxiliary materials and the addition amount of each component in the step S2 are as follows: cationic starch 8-10kg / ton of paper, Dry strength agent 10-15 kg / ton of paper, Wet strength agent 8-10 kg / ton of paper, Filler 200-220 kg / ton of paper, Internal sizing agent 15-20 kg / ton of paper, Retention agent 0.5-1.0 kg / ton of paper, Modified bentonite 3.0-4.0 kg / ton of paper.

[0012] Preferably, the internal sizing agent in the step S2 is a non-AKD type waterproof agent, and the paper absorption is controlled to be 20-24 g / m 2 , The retention agent is a cationic polyacrylamide, The dry strength agent is an amphoteric polyacrylamide, The wet strength agent is a melamine formaldehyde resin, The filler is a mixture of 50% light calcium carbonate and 50% heavy ground calcium carbonate, and the concentration of the under-net white water is controlled to be 0.2-0.3%.

[0013] Preferably, the surface sizing formula in the step S3 comprises a surface sizing agent, a surface sizing starch and an oxidation yellowing blocking agent, The surface sizing agent is a phenylpropyl surface reinforcing agent, the surface sizing starch is an enzyme converted corn starch, and the oxidation yellowing blocking agent is a mixture of sunflower acid ester and benzotriazole, The front and back surface sizing temperature of the paper sheet is 64-68℃, the front and back sizing agent concentration of the paper sheet is 15-18%, and the surface sizing amount of the paper sheet is 4.0-4.5 g / m 2 .

[0014] Preferably, the compound pressing process in the step S3 comprises: a first pressing line pressure of 920-930 KN / m, and a second pressing line pressure of 910-920 KN / m; The dry broke paper produced in the steps S3 and S4 is fully defibrated in a high-pressure thickener, and then re-enters a beating system to prepare pulp for papermaking, The concentration of the high-pressure thickener is 15-18%, and 10-15 kg / ton of paper of sodium hydroxide and 20-30 kg / ton of paper of hydrogen peroxide are added, and the temperature is controlled to be 85-90℃, and the treatment time is 30-60 minutes.

[0015] The present application has the following advantages over the prior art: 1. The present application starts from the research of fiber raw materials, and a high bulk cash register heat-sensitive base paper is prepared by mixing bleached conifer chemical pulp, bleached broad-leaved wood chemical pulp and chemi-mechanical pulp after beating in a certain ratio and adding functional chemical additives, so that the paper has high bulk, good dry and wet strength and surface strength, good heat-sensitive printing color developing effect and image preservation time, and delicate hand feeling, which meets the high use requirement and quality requirement of people on the high bulk cash register heat-sensitive base paper.

[0016] 2. In the manufacturing method of the present application, the fiber raw materials are bleached conifer chemical pulp (mixed pulp of larch, Korean pine and spruce), bleached poplar chemical pulp and bleached eucalyptus chemi-mechanical pulp, and the combination of the three kinds of fiber raw materials improves the bulk of the paper, the heat-sensitive printing color developing effect is good, and the hand feeling is delicate.

[0017] 3. In the manufacturing method of the present application, cationic starch, amphoteric polyacrylamide and melamine formaldehyde resin are added into the pulp, and benzene propyl surface enhancer and enzyme converted corn starch are added into the surface coating, so that the dry and wet strength and surface strength are improved, the problems of paper shedding, powder dropping and broken head in the coating process are solved, and the heat-sensitive printing image is clear and clean.

[0018] 4. In the manufacturing method of the present application, cationic acrylic waterproof agent is added into the pulp to replace the traditional AKD sizing, so that the problem of white transparent point caused by the hydrolysis product of AKD sizing is solved.

[0019] 5. In the manufacturing method of the present application, oxidation yellowing isolation agent is added into the surface sizing, which blocks the reaction between the high content lignin in the chemi-mechanical pulp and the heat-sensitive color developing agent, blocks the photo-oxidation yellowing, so that the heat-sensitive printing color developing effect and image preservation time are good.

[0020] 6. In the present application, the process parameters such as pulp beating degree, pulp ratio, auxiliary material amount, wire concentration, lip opening of headbox, pulp / wire speed ratio, compound press pressure, drying moisture and calender pressure are strictly controlled, so that the bulk, strength, heat-sensitive color developing and image preservation performance of the paper meet the use requirement of customers.

[0021] 7. In the manufacturing method of the present application, the dry loss paper generated in the papermaking process of the high bulk cash register heat-sensitive base paper is treated by combining the disintegration of pressure high consistency disintegrator with the beating of disc refiner, the dry loss paper is completely defibrated into single fibers, and is reused to make the high bulk cash register heat-sensitive base paper, which does not affect the physical strength and flatness of the paper. The pressure high consistency disintegrator controls the disintegration concentration, temperature and chemical amount, and the dry loss paper is pumped to the beating system to be re-dispersed and made into paper after being treated for 30-60 minutes.

[0022] In summary, the manufacturing method of the high bulk thickness cash register heat-sensitive base paper provided by the present application improves the bulk thickness, dry and wet strength and surface strength of the heat-sensitive base paper, and the color developing performance and image preservation performance of the heat-sensitive paper after processing are improved. The present application solves the technical problems of powder dropping and paper breaking of the high bulk thickness high proportion chemical pulp in the processing process, solves the technical problems of poor color developing performance and image preservation performance due to high proportion of chemical pulp, solves the quality problem of white transparent points on the surface of the paper, solves the problem of difficult recycling of dry loss paper generated in the papermaking process, and solves the problem of difficult recycling of dry loss paper generated in the papermaking process. After coating processing, the high bulk thickness cash register heat-sensitive base paper is used for recording transaction details of cash registers, belongs to industrial base paper, and has high quality requirements. The development of this kind of paper not only improves the competitiveness of enterprises, but also lays a foundation for long-term and healthy development of enterprises. Due to the high bulk thickness and low unit area use gram weight, good economic and social benefits can be brought. DETAILED DESCRIPTION

[0023] In order to make the skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0024] Embodiment 1: The present application provides a preparation method of 60g high bulk thickness cash register heat-sensitive base paper, comprising the following operation steps: S1, the bleached coniferous wood chemical pulp, the bleached broad-leaved wood chemical pulp and the bleached chemical pulp are respectively beaten, the bleached coniferous wood chemical pulp, the bleached broad-leaved wood chemical pulp and the bleached chemical pulp after beating are mixed in a certain proportion to form a mixed pulp; S2, the auxiliary materials are added to the mixed pulp and uniformly mixed, the uniform mixing dilution concentration is 2.8%, and then the sand is removed through the screening system, the pulp is diluted, the pulp net concentration is 0.75%, the lip opening degree of the headbox is controlled to be 9.5mm, the headbox pressure head is controlled to be 240Kpa, and the wet paper sheet is completed in the wire part; S3, the wet paper sheet enters the press section to be compounded, the paper sheet dryness is 43% after compounding, then enters the front drying cylinder for drying, the paper sheet moisture is 8% after drying, then the paper sheet surface treatment sizing is carried out, and the paper sheet moisture content is maintained at 6.5% after the sizing surface treatment enters the rear drying cylinder; S4, the dry paper sheet enters the calendering area for paper finishing, the line pressure of the calendering area is 16N / mm, the roller surface temperature is 56℃, and the paper sheet with the required smoothness is obtained, that is, the high bulk thickness cash register heat-sensitive base paper.

[0025] In this embodiment, the beating consistency of the bleached softwood chemical pulp in step S1 is controlled at 4.5%, and the beating degree is controlled at 40±2°SR; the beating consistency of the bleached hardwood chemical pulp is controlled at 4.0%, and the beating degree is controlled at 36±2°SR; the beating consistency of the bleached mechanical pulp is controlled at 4.0%, and the beating degree is controlled at 43±2°SR.

[0026] In this embodiment, the bleached softwood chemical pulp, the bleached hardwood chemical pulp and the bleached mechanical pulp in step S1 are configured as follows in terms of mass percentage: bleached softwood chemical pulp 27%, bleached hardwood chemical pulp 10%, bleached mechanical pulp 63%.

[0027] In this embodiment, the bleached softwood chemical pulp in step S1 is mixed pulp made of larch, red pine and spruce, and has high dry strength and wet strength, and the ISO brightness of the pulp is 87%. The bleached hardwood chemical pulp is made of poplar, and the paper made of the pulp is fine and has good flatness and high smoothness, and the ISO brightness of the pulp is 88%. The bleached mechanical pulp is made of eucalyptus, and the paper made of the pulp is high in bulk, and the ISO brightness of the pulp is 73%.

[0028] In this embodiment, the components contained in the auxiliary materials in step S2 and the adding amount of each component are as follows: cationic starch 8 kg / ton of paper, dry strength agent 15 kg / ton of paper, wet strength agent 10 kg / ton of paper, filler 220 kg / ton of paper, pulp internal sizing agent 20 kg / ton of paper, retention agent 0.5 kg / ton of paper, modified bentonite 3.0 kg / ton of paper.

[0029] The pulp internal sizing agent is a non-AKD type waterproof agent, and the paper absorption is controlled at 22 g / m 2 The retention agent is cationic polyacrylamide, the dry strength agent is amphoteric polyacrylamide, the wet strength agent is melamine formaldehyde resin, the filler is a mixture of 50% light calcium carbonate and 50% heavy ground calcium carbonate, and the concentration of the white water under the wire is controlled at 0.2%.

[0030] In this embodiment, the formula of the surface sizing in step S3 includes a surface sizing agent, surface sizing starch and an oxidation yellowing blocking agent, wherein the surface sizing agent is a phenylpropyl surface reinforcing agent, the surface sizing starch is enzyme-converted corn starch, and the oxidation yellowing blocking agent is a mixture of sunflower acid ester and benzotriazole at a ratio of 1:2. The surface sizing temperature of the front and back surfaces of the paper sheet is 65°C, the sizing agent concentration of the front and back surfaces of the paper sheet is 17%, and the surface sizing amount of the paper sheet is 4.0 g / m 2 .

[0031] In this embodiment, the composite pressing process in step S3 includes: a first pressing line pressure of 920 KN / m and a second pressing line pressure of 910 KN / m; after the dry paper generated in steps S3 and S4 is fully disintegrated in a high-consistency paper mill, it is reintroduced into the pulping system to prepare pulp for papermaking. The high-consistency paper mill has a concentration of 15%, and 10 kg / ton of sodium hydroxide and 20 kg / ton of hydrogen peroxide are added. The temperature is controlled at 90°C, and the treatment lasts for 45 minutes.

[0032] Comparative Example 1: In step S1 of Example 1, the bleached softwood chemical pulp was replaced with local pine, and the bleached eucalyptus chemimechanical pulp was replaced with poplar. The remaining raw materials and processes were the same as in Example 1.

[0033] Comparative Example 2: In step S3 of Example 1, no specific functional enhancement additives were added to the pulp or its surface, while the remaining raw materials and processes were the same as in Example 1.

[0034] Comparative Example 3: In step S3 of Example 1, no specific oxidative yellowing barrier was added to the surface sizing, and the remaining raw materials and processes were the same as in Example 1.

[0035] The high bulk thickness cash register thermal base paper prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 2 was subjected to quality testing. The test results are shown in Table 1 below: Table 1 Quality Test Results

[0036] As can be seen from Table 1 above, the physical properties of the paper prepared in Example 1 meet the quality requirements of high bulk thermal paper for cash registers. In Comparative Example 1, the bleached softwood chemical pulp in Example 1 was replaced with local pine, and the bleached eucalyptus chemimechanical pulp was replaced with poplar. The bulk of the paper prepared did not meet the requirements, and the breaking length of the paper also decreased. In Comparative Example 2, no specific functional enhancing agents were added to the pulp and the surface. The dry and wet breaking length and surface strength of the paper prepared did not meet the requirements. In Comparative Example 3, no specific oxidative yellowing barrier was added to the surface sizing. After thermal coating, the thermal color development performance and image preservation performance of the paper prepared did not meet the requirements.

[0037] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-mat thickness cash register thermal original paper, characterized by, The method comprises the following steps: S1, bleaching needle leaf wood chemical pulp, bleaching broadleaf wood chemical pulp and bleaching mechanical pulp are respectively beaten, the bleaching needle leaf wood chemical pulp, the bleaching broadleaf wood chemical pulp and the bleaching mechanical pulp after beating are mixed in a certain proportion to form mixed pulp; S2, auxiliary materials are added into the mixed pulp and uniformly mixed, the uniformly mixed pulp is diluted to a concentration of 2.5-3.5%, then the sand is removed through a screening system, the refined pulp is diluted, the pulp concentration on the wire is 0.75-0.80%, the lip opening of the headbox is controlled to be 9.5-10.0 mm, the headbox pressure is controlled to be 230-240 Kpa, and the wet paper sheet is formed in the wire part; S3, the wet paper sheet enters the press section and is first subjected to compound pressing, the paper sheet dryness is 40-45% after compound pressing, then the paper sheet enters the front drying cylinder for drying, the paper sheet moisture is less than 8% after drying, then the paper sheet surface is treated and sized, the paper sheet enters the rear drying cylinder for drying after surface sizing treatment, and the paper sheet moisture content is maintained at 6.5-7.0%; S4, the dry paper sheet enters the calendering area for paper finishing, and the paper with the smoothness meeting the requirements is obtained, that is, the high bulk thickness silver hot sensitive base paper.

2. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to claim 1, characterized in that, In the step S1, the beating concentration of the bleaching needle leaf wood chemical pulp is controlled to be 4.0-4.5%, and the beating beating degree is controlled to be 40±2°SR; The beating concentration of the bleaching broadleaf wood chemical pulp is controlled to be 3.5-4.0%, and the beating beating degree is controlled to be 36±2°SR; The beating concentration of the bleaching mechanical pulp is controlled to be 3.5-4.0%, and the beating beating degree is controlled to be 43±2°SR.

3. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to claim 1, characterized in that, In the step S1, the bleaching needle leaf wood chemical pulp, the bleaching broadleaf wood chemical pulp and the bleaching mechanical pulp are configured according to the following mass percentage: The bleaching needle leaf wood chemical pulp is 22-28%, The bleaching broadleaf wood chemical pulp is 10-15%, The bleaching mechanical pulp is 60-65%.

4. The method for preparing high-bulk, thick thermal paper for silver registers according to claim 1, characterized in that, In the step S1, the bleaching needle leaf wood chemical pulp is mixed pulp of larch, red pine and spruce.

5. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to claim 1, characterized in that, In the step S1, the bleaching broadleaf wood chemical pulp is made of poplar.

6. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to claim 1, characterized in that, In the step S1, the bleaching mechanical pulp is made of eucalyptus.

7. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to any one of claims 1-6, characterized in that, In the step S2, the components contained in the auxiliary materials and the addition amount of each component are as follows: Cationic starch 8-10 kg / ton of paper, Dry strength agent 10-15 kg / ton of paper, Wet strength agent 8-10 kg / ton of paper, Filler 200-220 kg / ton of paper, Pulp sizing agent 15-20 kg / ton of paper, Retention aid 0.5-1.0 kg / ton of paper, Modified bentonite 3.0-4.0 kg / ton of paper.

8. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to claim 7, characterized in that, The sizing agent in step S2 is a non-AKD waterproofing agent, and the paper absorbency is controlled at 20-24 g / m 2 , The retention aid is cationic polyacrylamide, The dry strength agent is amphoteric polyacrylamide, The wet strength agent is melamine formaldehyde resin, The filler is a mixture of 50% light calcium carbonate and 50% heavy ground calcium carbonate, and the white water concentration under the wire is controlled to be 0.2-0.3%.

9. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to any one of claims 1-6, characterized in that, In the step S3, the surface sizing formula includes surface sizing agent, surface sizing starch and oxidation yellowing blocking agent, The surface sizing agent is a phenylpropyl surface reinforcing agent, the surface sizing starch is enzyme converted corn starch, and the oxidation yellowing blocking agent is a mixture of sunflower acid ester and benzotriazole substance, The temperature of the front and back surface sizing of the paper sheet is 64-68°C, the concentration of the sizing material of the front and back surface of the paper sheet is 15-18%, and the surface sizing amount of the paper sheet is 4.0-4.5g / m 2 .

10. The method for preparing high-bulk, thick thermal paper for silver-sensitive printing according to any one of claims 1-6, characterized in that, In the step S3, the compound pressing process includes: the first line pressure is 920-930 KN / m, and the second line pressure is 910-920 KN / m. The dry broke paper produced in steps S3 and S4 is fed into a pressure high consistency refiner for defibration and then fed into a pulp preparation system for making pulp for papermaking, The pressure high consistency refiner has a consistency of 15-18%, and 10-15 kg / t of paper of hydrogenated sodium hydroxide and 20-30 kg / t of paper of hydrogen peroxide are added, the temperature is controlled at 85-90°C, and the treatment time is 30-60 minutes.

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