Production process of environment-friendly baking base paper

Abstract

The invention discloses a production process of environment-friendly baking base paper, which is characterized in that bleached raw wood pulp is used as wood pulp, and the environment-friendly baking base paper is prepared by repulping, enzymatic degradation reaction, deslagging, serial pulping, low-chlorine wet strength agent addition, dilution, in-pulp sizing agent addition, netting, forming, squeezing, pre-drying, film transfer surface sizing, post-drying, two-stage press polishing and reeling. The fiber pulping enzyme is used, so that the pulping energy consumption is greatly reduced, the fiber length is reserved, the paper is high in strength, good in toughness and beneficial to baking of large food materials, the low-chlorine wet strength agent prevents chloropropanol by-products from exceeding the standard, the food contact requirement is met, and the film transfer sizing process enables the raw paper to be high in surface strength and low in water absorption; when the oil-proof agent is coated on the front side and the back side, the dosage of the oil-proof agent is close and uniform, the oil-proof agent does not fall off, the raw paper is high in smoothness and tightness after being subjected to two-stage calendering, and a finished product is good in film-forming property after being coated with the oil-proof agent and does not have the problem of adhesion with food.

Description

Technical Field

[0001] The invention belongs to the field of food baking paper, and in particular relates to a production process of baking base paper. Background Art

[0002] Baking paper is a kind of food paper made from baking base paper with silicon coated on one or both sides. It has the advantages of high temperature resistance, grease isolation, and anti-sticking. It is widely used in baking, barbecue, and food packaging. When in use, the silicone oil film on the surface of the paper can prevent grease penetration, prevent food from sticking to the paper and tray, and the high toughness can well meet the requirements of supporting and wrapping food. Due to its low cost and green environmental protection, this paper is favored by more and more people, and the market demand is increasing year by year.

[0003] The quality of baking paper greatly affects the quality of baking paper. In order to meet the use requirements of baking paper, baking paper needs to have high strength, tightness, smoothness and small smoothness difference, so as to control the amount of silicon coating, so that it has good anti-sticking performance and temperature resistance after silicon coating. At the same time, the selection of wet strength agent should meet the national requirements for food contact paper, especially the residual amount of chloropropanol in paper should meet the national standards. At present, the baking paper on the market is of varying quality, and there are still problems such as low strength, large amount of silicon coating, easy detachment of silicone oil, and adhesion of food to baking paper. At the same time, the energy consumption in the production process of base paper is large and the cost is high, so it is necessary to continuously study and improve the production process of base paper. Summary of the invention

[0004] The purpose of this invention is to provide a production process of environmentally friendly baking base paper with good toughness, small difference between the two sides, low silicone oil consumption, good film-forming property, low chlorine and low production energy consumption.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0006] The wood pulp ratio is 80% bleached coniferous pulp and 20% bleached broadleaf pulp. After the wood pulp is crushed, a pulping enzyme is added to the pulp at a dosage of 0.01-0.05% relative to the absolute dry pulp to pre-treat the pulp before grinding. The principle is that the enzyme decomposes the fiber P layer and S1 layer, making the fiber easy to absorb water and swell, and at the same time modifies the fiber surface to save pulping power consumption and enhance the fiber fibrillation. After the enzymatic reaction is completed, pulping is carried out. By setting the reversal of the disc mill teeth, the residence time of the pulp in the pulping area is increased to improve the pulping quality. The pulping degree is controlled at 75-78°SR, and the wet weight is 3-4g.

[0007] During the pulping process, a low-chlorine wet strength agent is added. The byproducts of 1,3-dichloro-2-propanol (DCP) and 3-chloro-1,2-propanediol (CPD) in the wet strength agent meet the requirements of food contact paper, ensuring human health and environmental safety. AKD is added to the flow system to ensure the water resistance of the base paper, which is then put on the screen for forming.

[0008] The surface temperature of the high-temperature section of the drying cylinder before the paper machine should be greater than 120℃ to inactivate the pulping enzyme. Then it enters the film transfer sizing machine. The film transfer sizing machine can transfer the surface sizing material to the paper surface in the form of a film, making the paper surface smooth and the film uniform. Especially with the 1799 model of polyvinyl alcohol as the glue, the glue amount on the front and back of the paper is 1.0-1.3g / m2 respectively. This makes the surface strength of the base paper high, the film forming property is good, the water absorption is low, the silicone oil has good film forming property after silicon coating, and it is not easy to separate from the paper surface. It can completely avoid the poor film forming property of the silicone oil caused by the traditional starch glue after the immersion sizing machine, and the finished paper disease that is easy to "fall off silicon". At the same time, slightly increasing the glue amount on the back, so that the glue amount on the back is 0.1-0.3g / m2 larger than the front, can greatly improve the difference in smoothness between the front and back sides and reduce the two-sidedness.

[0009] After drying, it enters the two-stage calender to improve the smoothness and tightness of the paper. In the first stage of calendering, the soft roller is the lower roller and the steel roller is the upper roller. In the second stage, the soft roller is the upper roller and the steel roller is the lower roller. This arrangement is also to reduce the difference between the two sides of the base paper. In terms of parameter settings, the line pressure of each section is 200-250KN / m, the calendering temperature of the first section is 100-150℃, and the calendering temperature of the second section is 150-200℃. The tightness, smoothness and difference between the two sides of the base paper after the calender can meet the standards.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The present invention provides a production process for environmentally friendly baking base paper. Due to the use of fiber beating enzyme, the energy consumption of beating is greatly reduced, and the fiber length is retained. The paper has high strength and good toughness, which is conducive to baking large food materials. The low-chlorine wet strength agent avoids excessive chloropropanol byproducts and meets the food contact requirements. The film transfer sizing process makes the base paper have high surface strength and low water absorption. When the oil-proofing agent is coated, the amount on the front and back sides is close and uniform, and the oil-proofing agent will not fall off. After two-stage calendering, the base paper has high smoothness and high tightness. After the oil-proofing agent is coated, the finished product has good film-forming properties and will not stick to food. DETAILED DESCRIPTION

[0012] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods:

[0013] Embodiment 1:

[0014] A method for preparing environmentally friendly baking base paper, the preparation steps are as follows:

[0015] Use 80% bleached conifer pulp and 20% bleached broadleaf pulp. After mixing and disintegrating in the pulper, adjust the pulp temperature to 50 degrees, add a pulping enzyme in an amount of 0.01% relative to the absolute dry pulp in the pulp tank, mix evenly and wait for 30 minutes. After that, it passes through the high-concentration slag remover and enters the series pulping machine. The rotation direction of the second disc mill of the series pulping machine is opposite to that of the front and rear disc mills. The pulping degree is controlled at 75-78°SR, and the wet weight is 3-4g. Then add low-chlorine wet strength agent to the pulp tank, the amount of which is 0.1% relative to the absolute dry pulp. Then add the sizing agent in the pulp at the inlet of the flushing pump, the amount of which is 0.2% relative to the absolute dry pulp. After that, the pulp is processed by low-concentration slag removal and screening and then put on the screen for forming. The surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 7%, and the sizing amount is controlled at 1.1g / m2. The sizing agent is polyvinyl alcohol 1799 solution. The dried paper enters the calender for final processing. The temperature of the first group of calenders is set to 100℃ and the pressure is set to 200KN / m. The temperature of the second group of calenders is set to 150℃ and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0016] Embodiment 2:

[0017] A method for preparing environmentally friendly baking base paper. Compared with Example 1, the enzyme reaction time in this example is increased to 50 minutes.

[0018] Use 80% bleached conifer pulp and 20% bleached broadleaf pulp. After mixing and disintegrating in the pulper, adjust the pulp temperature to 50 degrees, add a pulping enzyme in an amount of 0.01% relative to the absolute dry pulp in the pulp tank, mix evenly and wait for 50 minutes. After passing through the deslagging device, enter the pulping machine in series. The rotation direction of the second disc mill of the series pulping machine is opposite to that of the front and rear disc mills. The pulping degree is controlled at 75-78°SR, and the wet weight is 3-4g. Then add low-chlorine wet strength agent in the pulping tank, the amount of which is 0.1% relative to the absolute dry pulp. Then add the sizing agent in the pulp at the inlet of the flushing pump, the amount of which is 0.2% relative to the absolute dry pulp. After that, the pulp is removed by low concentration and screened before being put on the screen for forming. The surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 7%, and the sizing amount is controlled at 1.1g / m2. The sizing agent is polyvinyl alcohol 1799 solution. The dried paper enters the calender for final processing. The temperature of the first group of calenders is set to 100℃ and the pressure is set to 200KN / m. The temperature of the second group of calenders is set to 150℃ and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0019] Embodiment 3:

[0020] A method for preparing environmentally friendly baking base paper. Compared with Example 2, the enzyme dosage in this example is increased to 0.05% relative to the absolute dry pulp.

[0021] Use 80% bleached conifer pulp and 20% bleached broadleaf pulp. After mixing and disintegrating in the pulper, adjust the pulp temperature to 50 degrees, add a pulping enzyme in an amount of 0.05% relative to the absolute dry pulp in the pulp tank, mix evenly and wait for 50 minutes. After passing through the deslagging device, enter the pulping machine in series for pulping. The rotation direction of the second disc mill of the series pulping machine is opposite to that of the front and rear disc mills. The pulping degree is controlled at 75-78°SR, and the wet weight is 3-4g. Then add low-chlorine wet strength agent in the pulping tank, the amount of which is 0.1% relative to the absolute dry pulp. Then add the sizing agent in the pulp at the inlet of the flushing pump, the amount of which is 0.2% relative to the absolute dry pulp. After that, the pulp is removed by low concentration and screened before being put on the screen for forming. The surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 7%, and the sizing amount is controlled at 1.1g / m2. The sizing agent is polyvinyl alcohol 1799 solution. The dried paper enters the calender for final processing. The temperature of the first group of calenders is set to 100℃ and the pressure is set to 200KN / m. The temperature of the second group of calenders is set to 150℃ and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0022] Embodiment 4:

[0023] A method for preparing environmentally friendly baking base paper. Compared with Example 3, the dosage of low-chlorine wet strength agent in this example is increased to 0.15% relative to absolute dry pulp, and the amount of glue on the back side is increased to 1.3 g / m2.

[0024] Use 80% bleached conifer pulp and 20% bleached broadleaf pulp. After mixing and disintegrating in the pulper, adjust the pulp temperature to 50 degrees, add a pulping enzyme in an amount of 0.05% relative to the absolute dry pulp in the pulp tank, mix evenly and wait for 50 minutes. After passing through the deslagging device, enter the pulping machine in series for pulping. The rotation direction of the second disc mill of the series pulping machine is opposite to that of the front and rear disc mills. The pulping degree is controlled at 75-78°SR, and the wet weight is 3-4g. Then add low-chlorine wet strength agent in the pulping tank, the amount of which is 0.1% relative to the absolute dry pulp. Then add the sizing agent in the pulp at the inlet of the flushing pump, the amount of which is 0.2% relative to the absolute dry pulp. After that, the pulp is removed by low concentration and screened before being put on the screen for forming. The surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 8%, and the sizing amount is controlled at 1.3g / m2. The sizing agent is polyvinyl alcohol 1799 solution. The dried paper enters the calender for final processing. The temperature of the first group of calenders is set to 100℃ and the pressure is set to 200KN / m. The temperature of the second group of calenders is set to 150℃ and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0025] Embodiment 5:

[0026] A method for preparing environmentally friendly baking base paper. Compared with Example 4, the temperature of the second calender in this embodiment is set to 200°C.

[0027] Use 80% bleached conifer pulp and 20% bleached broadleaf pulp. After mixing and disintegrating in the pulper, adjust the pulp temperature to 50 degrees, add a pulping enzyme in an amount of 0.05% relative to the absolute dry pulp in the pulp tank, mix evenly and wait for 50 minutes. After passing through the deslagging device, enter the pulping machine in series for pulping. The rotation direction of the second disc mill of the series pulping machine is opposite to that of the front and rear disc mills. The pulping degree is controlled at 75-78°SR, and the wet weight is 3-4g. Then add low-chlorine wet strength agent in the pulping tank, the amount of which is 0.1% relative to the absolute dry pulp. Then add the sizing agent in the pulp at the inlet of the flushing pump, the amount of which is 0.2% relative to the absolute dry pulp. After that, the pulp is removed by low concentration and screened before being put on the screen for forming. The surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 8%, and the sizing amount is controlled at 1.3g / m2. The sizing agent is polyvinyl alcohol 1799 solution. After the paper is dried, it enters the calender for final processing. The temperature of the first group of calenders is set to 100℃, the pressure is set to 200KN / m, and the temperature of the second group of calenders is set to 200℃, and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0028] Comparative Example 1:

[0029] A method for preparing environmentally friendly baking base paper. Compared with Example 1, this comparative example does not add beating enzyme, uses traditional PAE wet strength agent, and the gluing amount on the front and back sides is 1.0 g / m2.

[0030] 80% bleached conifer pulp and 20% bleached broadleaf pulp are used. After mixing and disintegrating in the pulper, the pulper enters the pulper for series pulping after passing through the deslagging device. The second disc mill of the series pulper rotates in the opposite direction to the front and rear disc mills. The pulping degree is controlled at 75-78°SR and the wet weight is 3-4g. Then, the traditional PAE wet strength agent is added to the pulp mixing tank, and the dosage is 0.1% relative to the absolute dry pulp. Then, the pulp sizing agent is added to the inlet of the pulp pump, and the dosage is 0.2% relative to the absolute dry pulp. After that, the pulp is removed from the low concentration and screened before being put on the net for forming. The cylinder surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing agent is polyvinyl alcohol 1799 solution. After drying, the paper enters the calender for final processing. The temperature of the first calender is set at 100℃ and the pressure is set at 200KN / m. The temperature of the second calender is set at 150℃ and the pressure is set at 250KN / m. Finally, the paper enters the winding process.

[0031] Comparative Example 2:

[0032] A method for preparing environmentally friendly baking base paper. Compared with Example 1, the second group of calendering temperature in this comparative example is set to 200°C.

[0033] 80% bleached conifer pulp and 20% bleached broadleaf pulp are used. After mixing and disintegrating in the pulper, the pulper enters the pulper for series pulping after passing through the deslagging device. The second disc mill of the series pulper rotates in the opposite direction to the front and rear disc mills. The pulping degree is controlled at 75-78°SR and the wet weight is 3-4g. Then, the traditional PAE wet strength agent is added to the pulp mixing tank, and the dosage is 0.1% relative to the absolute dry pulp. Then, the pulp sizing agent is added to the inlet of the pulp pump, and the dosage is 0.2% relative to the absolute dry pulp. After that, the pulp is removed from the low concentration and screened before being put on the net for forming. The cylinder surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then it enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing agent is polyvinyl alcohol 1799 solution. After drying, the paper enters the calender for final processing. The temperature of the first calender is set to 100℃ and the pressure is set to 200KN / m. The temperature of the second calender is set to 200℃ and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0034] Comparative Example 3:

[0035] A method for preparing environmentally friendly baking base paper. Compared with Example 1, in this comparative example, oxidized starch is used as the surface glue.

[0036] 80% bleached conifer pulp and 20% bleached broadleaf pulp are used. After mixing and disintegrating in the pulper, the pulper enters the pulper for series pulping after passing through the deslagging device. The second disc mill of the series pulper rotates in the opposite direction to the front and rear disc mills. The pulping degree is controlled at 75-78°SR and the wet weight is 3-4g. Then, the traditional PAE wet strength agent is added to the pulp mixing tank, and the dosage is 0.1% relative to the absolute dry pulp. Then, the pulp sizing agent is added to the inlet of the pulp pump, and the dosage is 0.2% relative to the absolute dry pulp. After that, the pulp is deslagging and screening at low concentration and then put on the net for forming. The cylinder surface temperature of the high temperature section of the drying cylinder before the paper machine is adjusted to 120℃, and then enters the film transfer sizing machine. The sizing concentration of the front side of the base paper is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing concentration of the back side is set to 6%, and the sizing amount is controlled at 1.0g / m2. The sizing agent is oxidized starch. After drying, the paper enters the calender for final processing. The temperature of the first calender is set to 100℃ and the pressure is set to 200KN / m. The temperature of the second calender is set to 200℃ and the pressure is set to 250KN / m. Finally, the paper enters the winding process.

[0037] Test example:

[0038] 1. Comparison of energy consumption of pulping

[0039] Test samples: environmentally friendly baking base paper prepared in Examples 1, 2, 3 and Comparative Example 1.

[0040] The pulping energy consumption monitored during the pulping process according to the above-mentioned embodiments and comparative examples is shown in Table 1.

[0041] Comparative Example 1 Example 1 Example 2 Example 3 Energy consumption of pulping KW.h / ton pulp 420 330 300 220 Pulping degree °SR 76 76 77 78 Wet weight of pulp g 3.8 3.7 3.5 3.3

[0042] Table 1

[0043] 2. Performance Testing

[0044] Test sample: environmentally friendly baking base paper prepared in each embodiment and comparative example.

[0045] The main physical indicators of the environmentally friendly baking base paper prepared according to the above embodiments and comparative examples of the present invention are shown in Table 2.

[0046] project unit Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Weight <![CDATA[g / m 2 ]]> 39.3 39.1 38.9 38.8 38.7 39.1 39.2 39.0 Moisture ％ 5.6 5.7 5.7 5.9 5.9 5.6 5.5 5.6 Tightness <![CDATA[g / cm 3 ]]> 0.92 0.93 0.93 0.94 0.94 0.92 0.93 0.92 Longitudinal tensile strength KN / m 4.0 4.0 4.0 4.1 4.2 3.7 3.8 3.0 Longitudinal wet strength KN / m 0.53 0.53 0.57 0.65 0.68 0.5 0.53 0.35 Positive water absorption <![CDATA[g / m 2 ]]> 16.3 16.2 16.2 16.3 16.2 16.5 16.5 21.5 Reverse side water absorption <![CDATA[g / m 2 ]]> 16.5 16.3 16.4 16.0 15.8 16.7 16.6 22.0 Frontal smoothness s 115 114 115 112 114 115 113 115 reverse smoothness s 82 85 85 95 101 70 82 83 transparency ％ 58.3 58.7 59 59.2 59.6 58 58.5 58.1

[0047] Table 2

[0048] The above-listed embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention, and the patent protection scope of the present invention shall be defined by the claims.

Claims

1. A production process for environmentally friendly baking base paper, which comprises the following steps: using bleached virgin wood pulp, compounding coniferous wood pulp and broadleaf wood pulp, using a pulping enzyme to pre-treat the pulp before grinding, and then pulping; then adding additives, and sequentially undergoing the papermaking process of forming, pressing, pre-drying, film transfer surface sizing, post-drying, two-stage calendering, and winding to prepare environmentally friendly baking base paper.

2. The production process of an environmentally friendly baking base paper according to claim 1, characterized in that: The mass ratio of the softwood pulp to the hardwood fiber is 80%:20%.

3. The production process of an environmentally friendly baking base paper according to claim 1, characterized in that: The pulping enzyme is a papermaking bioenzyme preparation composed of a variety of bioenzymes. The dosage is 0.01-0.05% relative to the absolute dry pulp. The pretreatment time is 30-60 minutes and the pretreatment temperature is 50-60°C.

4. The production process of an environmentally friendly baking base paper according to claim 1, characterized in that: The beating is carried out in two stages. Three disc mills are set in series for beating. Among the three disc mills, the rotation direction of the grinding teeth of the second disc mill is opposite to that of the front and rear disc mills. The pulping degree is 75-78°SR and the wet weight is 3-4g.

5. The production process of environmentally friendly baking paper according to claim 1, characterized in that: The auxiliary agent is polyamide polyamine epichlorohydrin (PAE), and the dosage is 0.1-0.15% relative to the absolute dry pulp.

6. The production process of environmentally friendly baking base paper according to claim 1, characterized in that: The auxiliary agent is alkyl ketene dimer (AKD), and the dosage is 0.2-0.25% relative to the absolute dry pulp.

7. The production process of environmentally friendly baking base paper according to claim 1, characterized in that: The cylinder surface temperature in the pre-drying high-temperature section is >120°C, which is used to inactivate the pulping enzyme.

8. The process for producing environmentally friendly baking paper according to claim 1, characterized in that: The film transfer surface sizing is applied on both the front and back sides of the paper, with the gluing amounts being 1.0-1.3 g / m2 respectively, and the gluing amount on the back side is 0.1-0.3 g / m2 greater than that on the front side.

9. The production process of environmentally friendly baking paper according to claim 1, characterized in that: The surface sizing agent is polyvinyl alcohol with a polymerization degree of 1700 and an alcoholysis degree of 99%, and the surface sizing concentration is 6.0-8.0%.

10. The process for producing environmentally friendly baking paper according to claim 1, characterized in that: The two-stage calendering adopts a two-stage calendering machine, in which the soft rollers and steel rollers are arranged alternately. The soft rollers in the first stage are The upper roller is the steel roller, the lower roller is the steel roller; the second section soft roller is the lower roller, the steel roller is the upper roller; the line pressure is 200-250KN / m, The calendering temperature is 100-200°C.