Plastic-free degradable release paper and preparation method thereof

Abstract

The invention provides plastic-free degradable release paper and a preparation method thereof. The preparation method comprises the steps that raw paper is manufactured, paper pulp of the raw paper comprises wood pulp, filler, cationic starch and an internal reinforcing agent, and the internal reinforcing agent is a glyoxal modified polymer; carrying out surface sizing on the raw paper; and coating the surface of the body paper subjected to sizing. According to the preparation method of the plastic-free degradable release paper provided by the embodiment of the invention, the strength of the release body paper can be improved by adding the in-pulp reinforcing additive in the papermaking process of the release body paper.

Description

Technical Field

[0001] The present application relates to the technical field of papermaking, and specifically to a plastic-free and biodegradable release paper and a preparation method thereof. Background Art

[0002] Release paper, also known as silicone oil paper or anti-adhesive paper, mainly plays the role of isolating sticky substances and is commonly used in the fields of self-adhesive stickers. Release paper generally consists of three layers: the first layer is the release paper layer, the second layer is the barrier layer, and the third layer is the release agent layer. Among them, according to the different barrier layer materials, release paper can be subdivided into plastic release paper and plastic-free release paper.

[0003] Plastic release paper, as the name implies, is made by spraying a layer of plastic film on the surface of the base paper, and then coating the release agent on the surface of the coated paper. At present, polyethylene (PE) particles are mainly used for coating in China, and the coating amount is controlled at 15g / m2 per side. 2 Above. After the base paper is coated on the surface, its anti-penetration performance to the release agent is significantly improved. At the same time, after a higher coating amount, the flatness of the paper surface is further improved, effectively ensuring the uniformity of the silicone oil coating in the later stage and the stability of the peeling performance. However, polyethylene, as a high molecular polymer, is extremely difficult to be naturally degraded in nature due to its special and stable chemical structure; the coating layer is insoluble in acid and alkali, and it is extremely difficult to recycle and process during the waste paper pulping process, so plastic release paper often faces the dilemma of being difficult to recycle.

[0004] At present, more environmentally friendly plastic-free release papers are also launched on the market, mainly glassine release paper, CCK release paper, etc. Among them, glassine release paper is made by super calendering glassine paper with high humidity and high temperature for many times, so that glassine paper has a highly closed surface, higher tightness and very low porosity, giving glassine paper the ability to resist grease, air and moisture, and then coated with silicone release agent on the surface to obtain glassine release paper; CCK release paper is made by coating kaolin + adhesive on the surface of CCK base paper through off-machine coating equipment. In order to improve the density of the coating, multiple layers of coating are required, and then after super pressure treatment, CCK release base paper can be obtained, and then silicone release agent is coated on the surface to obtain CCK release paper. Whether it is glassine release paper or CCK release paper, its processing technology is relatively complicated, and it is impossible to replace plastic release paper on a large scale. Summary of the invention

[0005] A first aspect of an embodiment of the present application provides a method for preparing a plastic-free biodegradable release paper, the method comprising:

[0006] Papermaking base paper, wherein the pulp of the base paper comprises: wood pulp, filler, cationic starch and an internal strengthening agent, and the internal strengthening agent is a glyoxal-modified polymer;

[0007] Applying surface sizing on base paper;

[0008] Coating is performed on the surface of the base paper after sizing.

[0009] In some optional embodiments, the glyoxal-modified polymer includes any one or a combination of glyoxal-modified amphoteric polyacrylamide, glyoxal-modified cationic polyacrylamide and glyoxal-modified anionic polyacrylamide; and the added amount of the pulp enhancer is 0.5-5 kg / ton pulp.

[0010] In some optional embodiments, the paper pulp further includes 0.5-2.5 kg / ton of pulp of alkenyl succinic anhydride, 0.1-0.5 kg / ton of pulp of cationic polyacrylamide and 1-5 kg / ton of pulp of colloidal silicon dioxide.

[0011] In some optional embodiments, in the step of applying surface sizing on the base paper, the surface sizing agent includes starch and amylase, the starch is one or a combination of two of corn starch and cassava starch; the amylase is selected from any one or more of α-amylase, β-amylase, and pullulanase, and the added amount of the amylase is 50-100 ppm.

[0012] In some optional embodiments, the solid content of the surface sizing agent is 10-15%, the viscosity of the glue is 10-15 cps, and the pH value of the glue is 8.0-8.5.

[0013] In some optional embodiments, in the step of coating the surface of the base paper after sizing, the coating includes pigments, high molecular polymers, water repellents and barrier agents; wherein the pigment includes 30-50 parts by mass, and the pigment is selected from one or more of nano-kaolin, nano-calcium carbonate, nano-titanium dioxide and nano-silicon dioxide; the solid content of the coating is 15-35%; and the single-sided coating amount is 8-15g / m2.

[0014] In some optional embodiments, the mass fraction of the high molecular polymer is 10-50 parts, and the high molecular polymer is selected from one or more of nanocellulose, polyvinyl alcohol, sodium alginate, chitosan, and guar gum.

[0015] In some optional embodiments, the mass proportion of the water repellent is 10-30 parts, and the water repellent is selected from any one or more combinations of water-based silane coupling agent, melamine glyoxal resin, melamine formaldehyde resin, polyamide polyepichlorohydrin resin, polyamide polyamine epichlorohydrin, and zirconium carbonate salt type water repellent; the mass proportion of the barrier is 40-60 parts, and the barrier is selected from one or more of acrylic resin, polymethyl silicone resin, polyethyl silicone resin, and ethylene-vinyl acetate copolymer resin.

[0016] In some optional embodiments, the preparation method further comprises: coating a release agent on the surface of the coated layer after coating.

[0017] In a second aspect, an embodiment of the present application provides a plastic-free and biodegradable release paper, which is prepared by the preparation method described in the above embodiment.

[0018] The method for preparing plastic-free biodegradable release paper provided in the embodiment of the present application can improve the strength of the release paper by adding an in-pulp reinforcing additive during the papermaking process of the release paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a schematic flow chart of an embodiment of a method for preparing plastic-free biodegradable release paper of the present application;

[0021] Figure 2 It is a schematic flow chart of another embodiment of the method for preparing the plastic-free biodegradable release paper of the present application;

[0022] Figure 3 It is a schematic diagram of the stacking structure of an embodiment of the release paper of the present application. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0024] The terms "first", "second", and "third" in the embodiments of the present application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", and "third" can expressly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the embodiments of the present application, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. The terms "including" and "having" in the embodiments of the present application and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or components inherent to these processes, methods, products, or devices.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] The peeling performance of the release paper surface is related to the bonding performance between the base paper and the barrier coating, and whether the release paper will be delaminated or damaged during the later use process. In order to improve the surface peeling performance of the base paper, the present invention makes the following innovative designs in the base paper making process: it is proposed to add a pulp reinforcing additive to the slurry. Since its own structure contains a large number of active groups, it can form hydrogen bonds with the hydroxyl groups in the fiber, thereby improving the strength of the paper; in the process of sizing the base paper surface, a special surface sizing solution preparation process is developed to improve the surface sizing starch strength, thereby improving the surface peeling performance of the base paper.

[0027] The way to prepare the release paper barrier layer with higher economic value is to prepare plastic release paper through polyethylene coating, but environmental issues and the problem that waste paper cannot be recycled cannot be ignored; while the plastic-free release paper adopts multi-layer coating of kaolin + super calendering, or super calendering under high temperature and high humidity conditions, which have the defects of complex process and large equipment investment. To this end, the present invention designs a special new barrier coating, which, after being coated on the surface of the release base paper, not only effectively improves the flatness and uniformity of the release base paper, but also can achieve the purpose of blocking the penetration of silicone oil. At the same time, the release base paper designed by the present invention can be degraded under natural conditions, and has the characteristics of environmental protection and greenness; under high temperature and alkaline conditions, the release paper waste can be normally decomposed, has good re-pulping characteristics, and can realize the recycling of waste paper.

[0028] See also Figure 1 , Figure 1 It is a flow chart of an embodiment of a method for preparing plastic-free biodegradable release paper of the present application, and the preparation method includes but is not limited to the following steps.

[0029] Step S100, making base paper.

[0030] The pulp of the base paper includes: wood pulp, filler, cationic starch and an internal reinforcing agent, wherein the wood pulp includes 0-100 parts of bleached kraft coniferous wood pulp, beating degree 30-50°SR; 0-100 parts of bleached kraft broadleaf wood pulp, beating degree 30-50°SR; 0-10 parts of bleached chemical thermomechanical pulp, beating degree 30-50°SR; the amount of filler is 50-200 kg / ton of pulp; the amount of cationic starch is 5-15 kg / ton of pulp; the internal reinforcing agent is a glyoxal-modified polymer, which can specifically include any one or a combination of glyoxal-modified amphoteric polyacrylamide, glyoxal-modified cationic polyacrylamide and glyoxal-modified anionic polyacrylamide; the amount of the internal reinforcing agent added is 0.5-5 kg / ton of pulp. The internal reinforcing agent can be added between the pulping pool and the headbox.

[0031] Optionally, the paper pulp may further include 0.5-2.5 kg / ton of pulp of alkenyl succinic anhydride (ASA); 0.1-0.5 kg / ton of pulp of cationic polyacrylamide (CPAM); 1-5 kg / ton of pulp of colloidal silicon dioxide, etc.

[0032] Please continue reading Figure 1 The preparation method in this embodiment further includes step S200 of applying surface sizing on the base paper.

[0033] The surface sizing agent may include starch, amylase and sodium hydroxide, the starch may be one or a combination of corn starch and cassava starch; the amylase may be selected from any one or more of α-amylase, β-amylase and pullulanase, the amount of amylase added is 50-100ppm, and the amount of amylase added may be 50ppm, 60ppm, 65ppm, 80ppm, 100ppm and the like. The content of sodium hydroxide is 0-0.5%; the solid content of the surface sizing agent is 10-15%, the viscosity of the glue is 10-15cps, and the pH value of the glue is 8.0-8.5.

[0034] Please continue reading Figure 1 The preparation method in this embodiment further includes step S300, coating the surface of the base paper after sizing.

[0035] Optionally, the coating may include pigment, high molecular polymer, water repellent and barrier agent; the solid content of the coating is 15-35%; the single-side coating amount is 8-15g / m 2 The coating equipment is one of film transfer coating, rod coating, curtain coating, blade coating, air knife coating and the like.

[0036] The pigment comprises 30-50 parts by mass, specifically 30 parts by mass, 35 parts by mass, 38 parts by mass, 40 parts by mass, 50 parts by mass, etc. The pigment is selected from one or more of nano-kaolin, nano-calcium carbonate, nano-titanium dioxide, and nano-silicon dioxide; wherein the nano-kaolin requires flaky particles with a flaky diameter-thickness ratio of 20:1 to 50:1.

[0037] The mass fraction of the high molecular polymer is 10-50 parts, and the high molecular polymer is selected from one or more of nanocellulose, polyvinyl alcohol, sodium alginate, chitosan, and guar gum, and the high molecular polymer has excellent film-forming and adhesive properties. The mass fraction of the water repellent is 10-30 parts, and the water repellent is selected from any one or more of a water-based silane coupling agent, melamine glyoxal resin, melamine formaldehyde resin, polyamide polyepichlorohydrin resin, polyamide polyamine epichlorohydrin, and a zirconium carbonate salt type water repellent; the addition of the water repellent is intended to improve the water resistance of the release paper.

[0038] The mass proportion of the barrier agent is 40-60 parts, and the barrier agent is selected from one or more of acrylic resin, polymethyl silicone resin, polyethyl silicone resin, and ethylene-vinyl acetate copolymer resin. The barrier agent is used to improve the anti-permeability performance of the base paper.

[0039] The preparation method of the plastic-free degradable release paper in the embodiment of the present application is, first, to add an intra-pulp reinforcing agent during the papermaking process of the release base paper to improve the strength of the release base paper; the second is to develop a special surface sizing solution preparation process to improve the surface sizing starch strength and thus improve the surface peeling performance of the base paper; finally, a special new barrier coating is developed to achieve high barrier silicone oil penetration characteristics and high smoothness while also having the characteristics of natural degradation and re-pulp recycling; the plastic-free degradable release paper in this embodiment is different from the conventional plastic-free release paper. The plastic-free degradable release paper obtained in this embodiment adopts a special process to paper a release base paper with high peeling performance, thereby ensuring that the base paper has excellent surface peeling performance; then the new barrier coating is coated on the surface of the base paper, which not only effectively improves the flatness and uniformity of the release base paper, but also can achieve the purpose of blocking silicone oil penetration. It not only has excellent barrier performance, but also has the characteristics of green environmental protection and low investment cost, and has broad market prospects.

[0040] See also Figure 2 , Figure 2 It is a flow chart of another embodiment of the method for preparing the plastic-free biodegradable release paper of the present application, and the preparation method includes but is not limited to the following steps.

[0041] Step S100, making base paper.

[0042] The pulp of the base paper includes: wood pulp, filler, cationic starch and an internal reinforcing agent, wherein the wood pulp includes 0-100 parts of bleached kraft coniferous wood pulp, beating degree 30-50°SR; 0-100 parts of bleached kraft broadleaf wood pulp, beating degree 30-50°SR; 0-10 parts of bleached chemical thermomechanical pulp, beating degree 30-50°SR; the amount of filler is 50-200 kg / ton of pulp; the amount of cationic starch is 5-15 kg / ton of pulp; the internal reinforcing agent is a glyoxal-modified polymer, which can specifically include any one or a combination of glyoxal-modified amphoteric polyacrylamide, glyoxal-modified cationic polyacrylamide and glyoxal-modified anionic polyacrylamide; the amount of the internal reinforcing agent added is 0.5-5 kg / ton of pulp. The internal reinforcing agent can be added between the pulping pool and the headbox.

[0043] Optionally, the paper pulp may further include 0.5-2.5 kg / ton of pulp of alkenyl succinic anhydride (ASA); 0.1-0.5 kg / ton of pulp of cationic polyacrylamide (CPAM); 1-5 kg / ton of pulp of colloidal silicon dioxide, etc.

[0044] Please continue reading Figure 2 The preparation method in this embodiment further includes step S200 of applying surface sizing on the base paper.

[0045] The surface sizing agent may include starch, amylase and sodium hydroxide, the starch may be one or a combination of corn starch and cassava starch; the amylase may be selected from any one or more of α-amylase, β-amylase and pullulanase, the amount of amylase added is 50-100ppm, and the amount of amylase added may be 50ppm, 60ppm, 65ppm, 80ppm, 100ppm and the like. The content of sodium hydroxide is 0-0.5%; the solid content of the surface sizing agent is 10-15%, the viscosity of the glue is 10-15cps, and the pH value of the glue is 8.0-8.5.

[0046] Please continue reading Figure 2 The preparation method in this embodiment further includes step S300, coating the surface of the base paper after sizing.

[0047] Optionally, the coating may include pigments, high molecular polymers, water repellents and barrier agents; the solid content of the coating is 15-35%; the single-side coating amount is 8-15 g / m2. The coating equipment is one of film transfer coating, rod coating, curtain coating, blade coating, air knife coating and the like.

[0048] The pigment comprises 30-50 parts by mass, specifically 30 parts by mass, 35 parts by mass, 38 parts by mass, 40 parts by mass, 50 parts by mass, etc. The pigment is selected from one or more of nano-kaolin, nano-calcium carbonate, nano-titanium dioxide, and nano-silicon dioxide; wherein the nano-kaolin requires flaky particles with a flaky diameter-thickness ratio of 20:1 to 50:1.

[0049] The mass fraction of the high molecular polymer is 10-50 parts, and the high molecular polymer is selected from one or more of nanocellulose, polyvinyl alcohol, sodium alginate, chitosan, and guar gum, and the high molecular polymer has excellent film-forming and adhesive properties. The mass fraction of the water repellent is 10-30 parts, and the water repellent is selected from any one or more of a water-based silane coupling agent, melamine glyoxal resin, melamine formaldehyde resin, polyamide polyepichlorohydrin resin, polyamide polyamine epichlorohydrin, and a zirconium carbonate salt type water repellent; the addition of the water repellent is intended to improve the water resistance of the release paper.

[0050] The mass proportion of the barrier agent is 40-60 parts, and the barrier agent is selected from one or more of acrylic resin, polymethyl silicone resin, polyethyl silicone resin, and ethylene-vinyl acetate copolymer resin. The barrier agent is used to improve the anti-permeability performance of the base paper.

[0051] Different from the above-mentioned embodiment, the preparation method in this embodiment further includes step S400 of coating a release agent on the surface of the coated layer.

[0052] Specifically, the coating equipment can be used to apply solvent-free silicone oil, with the target dry silicone coating amount of 0.5-1.5g / m 2 .

[0053] See also Figure 3 , Figure 3 1 is a schematic diagram of the stacked structure of an embodiment of the release paper of the present application, in which 101 is marked as a base paper layer, 102 is marked as a surface sizing layer, 103 is marked as a coating layer, and 104 is marked as a silicone oil layer. In some other embodiments, the coating layer 103 is not limited to the one-layer structure in the figure, and can include a top coating layer and a surface lining layer on one side and a bottom coating layer on another layer, etc. The detailed features of this part are within the scope of understanding of those skilled in the art and will not be repeated here.

[0054] Several specific embodiments and comparative embodiments are introduced below for illustration.

[0055] Example 1

[0056] Control bleached kraft softwood pulp 20 parts, beating degree 38°SR; bleached kraft hardwood pulp 70 parts, beating degree 40°SR; bleached chemical thermomechanical pulp 10 parts, beating degree 45°SR; filler: 110kg / ton pulp; cationic starch: 8kg / ton pulp; polyacrylamide 2kg / ton pulp; alkenyl succinic anhydride (ASA) 0.8kg / ton pulp; cationic polyacrylamide (CPAM) 0.2kg / ton pulp; colloidal silica 2kg / ton pulp; control the base paper weight 75g / m 2 .

[0057] After forming, pressing and pre-drying, surface sizing is carried out: corn starch is used for surface sizing, and 90ppm of amylase and 0.05% of sodium hydroxide are added during cooking. The solid content of the sizing solution is controlled to be 12%, the viscosity of the sizing solution is 11cps, and the pH value of the sizing solution is 8.1. The single-side sizing amount is controlled to be 1.8g / m by a membrane transfer sizing machine. 2 .

[0058] After post-drying and calendering, the release paper is rolled up to obtain the release paper.

[0059] Apply barrier coating by scraper coater: set barrier coating formula: 45 parts of nano calcium carbonate, 50 parts of sodium alginate, 10 parts of polyvinyl alcohol, 40 parts of acrylic resin, set barrier coating solid content to 18%, control single-sided coating amount to 8g / m 2 .

[0060] Environmentally friendly plastic-free release paper is obtained through hot air drying, calendering and rolling.

[0061] Finally, the laboratory applies solvent-free silicone oil.

[0062] Example 2

[0063] Control bleached kraft softwood pulp 15 parts, beating degree 41°SR; bleached kraft hardwood pulp 79 parts, beating degree 40°SR; bleached chemical thermomechanical pulp 6 parts, beating degree 39°SR; filler: 80kg / ton pulp; cationic starch: 8kg / ton pulp; carboxymethyl cellulose 1.2kg / ton pulp; alkenyl succinic anhydride (ASA) 1.0kg / ton pulp; cationic polyacrylamide (CPAM) 0.2kg / ton pulp; colloidal silica 2kg / ton pulp; control the base paper weight 75g / m 2 .

[0064] After forming, pressing and pre-drying, surface sizing is carried out: corn starch is used for surface sizing, and 80ppm of amylase and 0.1% of sodium hydroxide are added during cooking. The solid content of the sizing solution is controlled to be 12.5%, the viscosity of the sizing solution is 12cps, and the pH value of the sizing solution is 8.2. The single-sided sizing amount is controlled to be 1.7g / m by a membrane transfer sizing machine. 2 .

[0065] After post-drying and calendering, the release paper is rolled up to obtain the release paper.

[0066] Apply barrier coating by scraper coater: set barrier coating formula: 20 parts of nano silicon dioxide, 20 parts of nano kaolin, 40 parts of chitosan, 10 parts of polyvinyl alcohol, 50 parts of polyethyl silicone resin, set barrier coating solid content to 20%, single-side coating amount to 11g / m 2 .

[0067] Environmentally friendly plastic-free release paper is obtained through hot air drying, calendering and rolling.

[0068] Finally, the laboratory applies solvent-free silicone oil.

[0069] Example 3

[0070] Control bleached kraft softwood pulp 20 parts, beating degree 40°SR; bleached kraft hardwood pulp 75 parts, beating degree 38°SR; bleached chemical thermomechanical pulp 5 parts, beating degree 40°SR; filler: 120kg / ton pulp; cationic starch: 8kg / ton pulp; polyacrylamide 5kg / ton pulp; alkenyl succinic anhydride (ASA) 0.9kg / ton pulp; cationic polyacrylamide (CPAM) 0.2kg / ton pulp; colloidal silica 2kg / ton pulp; control the base paper weight 75g / m 2 .

[0071] After forming, pressing and pre-drying, surface sizing is carried out: cassava starch is used for surface sizing, and 80ppm of amylase and 0.15% of sodium hydroxide are added after cooking. The solid content of the sizing solution is controlled to be 13.5%, the viscosity of the sizing solution is 13cps, and the pH value of the sizing solution is 8.4. The single-sided sizing amount is controlled to be 1.9g / m by a membrane transfer sizing machine. 2.

[0072] After post-drying and calendering, the release paper is rolled up to obtain the release paper.

[0073] Apply barrier coating by blade coater: set barrier coating formula: 40 parts of nano kaolin, 50 parts of nano cellulose, 5 parts of polyvinyl alcohol, 45 parts of ethylene-vinyl acetate copolymer resin, set barrier coating solid content to 28%, control single-sided coating amount to 14g / m 2 .

[0074] Environmentally friendly plastic-free release paper is obtained through hot air drying, calendering and rolling.

[0075] Finally, the laboratory applies solvent-free silicone oil.

[0076] Comparative Example 1

[0077] Commercially available release paper (uncoated), basis weight 75g / m 2 .

[0078] Comparative Example 2

[0079] Commercially available PE coated release paper (not coated with release agent), paper weight 94g / m 2 , of which the coating amount is 19g / m 2 , laboratory coating of solvent-free silicone oil.

[0080] Comparative Example 3

[0081] Commercially available CCK release paper (already coated with kaolin and overpressed, not coated with release agent), paper weight 120g / m 2 , of which kaolin coating amount is 20-25g / m 2 , laboratory coating of solvent-free silicone oil.

[0082] The main tested physical properties of each embodiment and the comparison are shown in the following table.

[0083]

[0084]

[0085] The above results show that:

[0086] The preparation method of the plastic-free and biodegradable release paper base paper in the embodiment of the present application is as follows: by designing a special release paper making process, the peeling performance of the base paper is improved; a new barrier coating is designed, and the prepared base paper has no penetration problem when coated with silicone oil, and the dry silicone coating amount is basically equivalent to the silicone coating effect of commercially available coated paper, maintaining a low release agent coating cost; testing the normal temperature / aging peeling effect, it is found that the release effect is equivalent to that of the coated release paper, the peeling performance is excellent, and it has a good user experience.

[0087] The above descriptions are only some embodiments of the present application, and do not limit the protection scope of the present application. Any equivalent device or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing plastic-free biodegradable release paper, characterized in that: The preparation method comprises: Papermaking base paper, wherein the pulp of the base paper comprises: wood pulp, filler, cationic starch and an internal strengthening agent, and the internal strengthening agent is a glyoxal-modified polymer; Applying surface sizing on base paper; Coating is performed on the surface of the base paper after sizing.

2. The preparation method according to claim 1, characterized in that: The glyoxal-modified polymer includes any one or a combination of glyoxal-modified amphoteric polyacrylamide, glyoxal-modified cationic polyacrylamide and glyoxal-modified anionic polyacrylamide; the added amount of the pulp enhancer is 0.5-5kg / ton pulp.

3. The preparation method according to claim 1, characterized in that: The paper pulp further comprises 0.5-2.5 kg / ton of alkenyl succinic anhydride, 0.1-0.5 kg / ton of cationic polyacrylamide and 1-5 kg / ton of colloidal silicon dioxide.

4. The preparation method according to claim 1, characterized in that: In the step of applying surface sizing on the base paper, the surface sizing agent includes starch and amylase, the starch is one or a combination of corn starch and cassava starch; the amylase is selected from any one or more of α-amylase, β-amylase, and pullulanase, and the addition amount of the amylase is 50-100 ppm.

5. The preparation method according to claim 4, characterized in that: The solid content of the surface sizing agent is 10-15%, the viscosity of the glue solution is 10-15 cps, and the pH value of the glue solution is 8.0-8.

5.

6. The preparation method according to claim 1, characterized in that: In the step of coating the surface of the base paper after sizing, the coating comprises a pigment, a polymer, a water repellent and a barrier agent; wherein the pigment comprises 30-50 parts by weight, and the pigment is selected from one or more of nano-kaolin, nano-calcium carbonate, nano-titanium dioxide and nano-silicon dioxide; the solid content of the coating is 15-35%; the single-side coating amount is 8-15g / m 2 .

7. The preparation method according to claim 6, characterized in that: The mass proportion of the high molecular polymer is 10-50 parts, and the high molecular polymer is selected from one or more of nano cellulose, polyvinyl alcohol, sodium alginate, chitosan, and guar gum.

8. The preparation method according to claim 7, characterized in that: The mass proportion of the water repellent is 10-30 parts, and the water repellent is selected from any one or more combinations of water-based silane coupling agent, melamine glyoxal resin, melamine formaldehyde resin, polyamide polyepichlorohydrin resin, polyamide polyamine epichlorohydrin, and zirconium carbonate salt type water repellent; the mass proportion of the barrier is 40-60 parts, and the barrier is selected from one or more of acrylic resin, polymethyl silicone resin, polyethyl silicone resin, and ethylene-vinyl acetate copolymer resin.

9. The preparation method according to claim 1, characterized in that: The preparation method further comprises: coating a release agent on the surface of the coated coating layer.

10. A plastic-free and biodegradable release paper, characterized in that: The release paper is prepared by the preparation method according to any one of claims 1 to 9.

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