Biodegradable paper adhesive tape and manufacturing method thereof

Abstract

The invention relates to a biodegradable paper adhesive tape and a manufacturing method of the biodegradable paper adhesive tape. Specifically, the biodegradable paper adhesive tape comprises: a paper backing base comprising a first side surface and a second side surface; the silicon release coating is directly formed on the first side face of the paper back base and comprises a first infiltration area, and the first infiltration area partially infiltrates into the first side face of the paper back base; the biodegradable water-based adhesive layer comprises a water-based acrylic acid adhesive and a polyurethane dispersing agent, the biodegradable water-based adhesive layer is directly formed on the second side face of the paper back base and comprises a second infiltration area, and the second infiltration area partially infiltrates into the second side face of the paper back base; wherein the initial adhesive force of the biodegradable paper adhesive tape according to a GB / T 4582-2002 test is at least greater than or equal to a No.9 ball, and the holding power of the biodegradable paper adhesive tape according to a GBT4851-2014 A test is at least greater than 24 hours.

Description

Background Art

[0002] As people's environmental awareness continues to increase, the recycling and reuse of materials and various resources has gradually attracted people's attention. In this context, the decomposability of resources or materials has become an important research field. By decomposing materials, we can not only reduce the impact on the environment, but also convert them into resources that can be reused. Among them, biodegradation, as a key direction, plays an important role in realizing resource recycling and environmental protection.

[0003] Adhesives or tapes are common items in daily life. For example, goods need to be properly packaged during transportation. In order to make the packaging tightly closed to protect the goods, adhesives or tapes are often needed, but most adhesives or tapes cannot be recycled. Currently, there are tapes made of degradable backing films, but the adhesives themselves are not degradable. Even if there are biodegradable tapes, their degradation rate or tape performance is not easy to balance. In other words, biodegradable tapes are still limited. In addition to packaging, tapes also play an important role in other fields. For example, they can be attached to the surface of objects for marking. Among them, paper tapes are widely used in stationery and office because of their writable properties.

[0004] Conventional paper tapes must use polymer or latex to form a coating or isolation layer, firstly to prevent the release layer or the coated adhesive from penetrating the paper substrate, and secondly to increase the structural strength. However, the polymer coating is usually a polyethylene (PE) coating, which is not conducive to biodegradability. CN118064062A discloses a degradable color printed kraft paper tape, which replaces the isolation film layer obtained by the traditional lamination process by pre-coating a degradable polymer waterproof coating isolation film layer on the surface, but it still has an isolation film layer; although there are kraft paper tapes with or without lamination or isolation layers, due to the removal of the lamination or isolation layer, the structural strength of the tape must be strengthened in other ways, such as CN116218400A, which is achieved by setting a rib net with tensile reinforcement and auxiliary reinforcement inside a double-layer kraft paper substrate; CN113004823A discloses a tensile degradable and environmentally friendly wet water kraft paper tape, but similarly, the kraft paper layer is connected to a reinforcement layer composed of yarn; CN212476609U has a reinforcement layer fixed between the paper tape layer and the first adhesive layer, and the reinforcement layer is a mesh structure woven from degradable fiber threads. These additional methods of increasing structural strength will increase the complexity of the process and may increase costs.

[0005] In addition, the use of water-based degradable adhesive materials helps to improve the degradability of tape products. However, if water-based adhesive materials are used on paper substrates, the structural strength will be reduced due to penetration, causing problems such as easy breakage of the tape. Therefore, degradable paper tapes mostly use adhesives that will not have penetration problems. For example, CN214781597U uses synthetic resin hot melt adhesive to make environmentally friendly degradable recycled paper tape. Summary of the invention

[0006] In view of this, the present invention provides a paper tape made of a water-based degradable adhesive and without a coating. Compared with the conventional paper tape with a coating, the paper tape of the present invention can omit the coating layer, which can not only save costs and simplify the process, but also remove the coating layer to help control the thickness required for the tape, and also help improve the biodegradability of the tape. In addition, the water-based adhesive used in the present invention has good adhesive properties, does not contain solvents and is environmentally friendly. In addition to improving the biodegradability, it also overcomes the problem that the coating of the water-based adhesive on the paper backing may cause the overall structural strength of the tape to be reduced. The paper tape produced also maintains good adhesive properties and can be used not only as a general office stationery paper tape, but also as a packaging tape.

[0007] In order to achieve the above-mentioned process effect, the technical solution of the present invention is: a biodegradable paper tape, comprising: a paper backing, a silicon release coating and a biodegradable water-based adhesive layer, the paper backing comprises a first side surface and a second side surface located on two opposite sides, the silicon release coating is directly formed on the first side surface of the paper backing and comprises a first penetration area, the first penetration area partially penetrates into the first side surface of the paper backing, the biodegradable water-based adhesive layer comprises a water-based acrylic adhesive and a polyurethane dispersant, and the biodegradable water-based adhesive layer is directly formed on the second side surface of the paper backing and comprises a second penetration area, the second penetration area partially penetrates into the second side surface of the paper backing, wherein the initial tack (Initial Tack) of the biodegradable paper tape tested by GB / T 4582-2002 is at least greater than or equal to a No. 9 ball, and the room temperature shear force (Room Temperature Shear Force) tested by GBT4851-2014 A is at least greater than 24 hours.

[0008] In some embodiments, the paper backing is a kraft paper backing.

[0009] In some embodiments, the first penetration area of ​​the silicone release coating does not exceed 50% of the thickness of the paper backing, and the second penetration area does not exceed 10% of the thickness of the paper backing.

[0010] In some embodiments, the water-based acrylic adhesive of the biodegradable water-based adhesive layer includes a water-based random copolymer, whose monomer units are selected from one or more of acrylate, methacrylate, acrylic acid, methacrylic acid, acrylamide, and methacrylamide; the polyurethane dispersant of the biodegradable water-based adhesive layer is an aqueous anion-modified polyurethane dispersant; and the biodegradable water-based adhesive layer further includes a tackifier, which is one or more selected from rosin resin, hydrogenated rosin resin, and terpene phenolic resin.

[0011] In some embodiments, the biodegradable water-based adhesive layer has a thickness of 15-20 μm, and the second infiltration zone occupies 1 / 3-1 / 4 of the biodegradable water-based adhesive layer.

[0012] In some embodiments, the biodegradable paper tape has a tensile strength of at least 50 N / cm as tested by GB / T 30776-2014, a 180° peel strength of at least 2.5 N / cm as tested by GBT 2792-2014, and an extensibility of at least 2%, and a composting degradation rate of at least 90% in 180 days as tested by GB / T 19277.1.

[0013] The present case further provides a method for manufacturing a biodegradable paper tape, comprising: providing a paper backing, the paper backing comprising a first side and a second side; providing a silicon release agent; coating the silicon release agent on the first side of the paper backing, the silicon release agent partially infiltrating the first side of the paper backing; drying the silicon release agent to form a silicon release coating on the first side of the paper backing, the silicon release coating comprising a first infiltration zone infiltrating the first side; providing a biodegradable water-based adhesive composition, the total solid content of which is at least 60% and comprises a water-based acrylic adhesive and a polyurethane dispersant; coating the biodegradable water-based adhesive composition on the second side of the paper backing, the biodegradable water-based adhesive composition partially infiltrating the second side of the paper backing; drying the biodegradable water-based adhesive composition to form a biodegradable water-based adhesive layer on the second side of the paper backing, the biodegradable water-based adhesive layer comprising a second infiltration zone infiltrating the second side; wherein the biodegradable paper tape is in accordance with GB / T The initial tack tested by 4582-2002 is at least greater than or equal to that of a No. 9 ball, and the room temperature shear force tested by GBT4851-2014 A is at least greater than 24 hours.

[0014] In some embodiments, the silicone release agent is a solvent-free silicone release agent having a viscosity of at least 350 mPa·s at room temperature. The silicone release agent can be coated on the first side of the paper backing by gravure coating or roller coating, and the coating thickness does not exceed 2 μm.

[0015] In some embodiments, the silicone release agent is dried by hot air at a drying temperature not lower than 145°C.

[0016] In some embodiments, the biodegradable water-based adhesive composition is dried by infrared light and hot air. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a biodegradable paper tape according to an embodiment of the present invention;

[0018] Figure 2 The present invention is a flow chart of manufacturing a biodegradable paper tape according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be described in more detail with reference to the accompanying drawings. It should be understood that, without departing from the scope or spirit of the present invention, those skilled in the art can conceive of other various embodiments and can modify them according to the teachings of this specification. Therefore, the following specific methods are only illustrative and not restrictive.

[0020] Unless otherwise indicated, all numbers used in this specification and claims to represent characteristic dimensions, quantities and physical properties should be understood as being modified by the term "about". Therefore, unless otherwise specified, the numerical parameters listed in this specification and the appended claims are approximate values. According to the teachings of the present invention, a person of ordinary skill in the art can appropriately change these approximate values ​​to obtain the desired properties. If the numerical range is expressed as endpoints, it includes all numbers within the range. In addition, the "biodegradable" described in this case refers to the test method specified in the Chinese national standard GB / T 19277.1-2011, and the final aerobic biodegradability and disintegration degree of the material within the prescribed test period exceed 90%.

[0021] See also Figure 1 , which is a schematic diagram of the structure of a biodegradable paper tape according to an embodiment of the present invention. Figure 1As shown, the biodegradable paper tape 1 may include a paper backing 11, a silicon release coating 12, and a biodegradable water-based adhesive layer 13, wherein the paper backing 11 includes two opposite first sides 111 and a second side 112, and the silicon release coating 12 and the biodegradable water-based adhesive layer 13 are respectively located on the first side 111 and the second side 112 of the paper backing 11, the silicon release coating 12 includes a first penetration area 121, and the biodegradable water-based adhesive layer 13 includes a second penetration area 131.

[0022] In this embodiment, the paper backing 11 may be a kraft paper backing with a thickness of about 80-90 μm. In addition, the kraft paper backing used in this case does not have any coating layer or barrier layer, and is more conducive to biodegradation than conventional kraft paper coated with polymer or kraft paper with barrier layer. Figure 1 As shown, the biodegradable paper tape 1 includes a silicon release coating 12. In this embodiment, the silicon release coating 12 is located on the first side 111 of the paper backing 11 and is formed by directly coating the first side 111 of the paper backing 11 with a silicon release agent. Since the paper backing 11 of the present invention is not coated with any coating, it should be understood that the silicon release agent partially penetrates into the first side 111 of the paper backing 11 and fills in the pores thereof and is directly formed on the first side 111 of the paper backing 11, and partially overlaps with the paper backing 11 to form a first penetration area 121 near the first side 111. In addition, since there is no other barrier material or material between the silicon release coating 12 and the paper backing 11, in some embodiments, when the release agent used is a solvent-free silicon release agent, the thickness of the release agent coating is equal to the thickness of the silicon release coating 12. In addition, it should be understood that when a solvent-free silicone release agent is used as a release agent, it will not penetrate into the other side of the paper backing 11. Therefore, the thickness of the silicone release coating 12 is not limited. However, due to cost considerations, the lowest coating amount that can achieve the release effect is still preferred. In this embodiment, the coating thickness of the solvent-free silicone release agent does not exceed 2 μm, for example, it can be between 1-2 μm. Since the surface of the paper backing 11 is a rough surface and has pores, the ratio of the solvent-free silicone release agent penetrating into the paper backing 11 is also about 1-2 μm. In other words, in this embodiment, when When the thickness of the paper backing 11 is 85 μm, the first penetration area 121 formed by the silicon release coating 12 penetrating into the paper backing 11 accounts for approximately 1.17%-2.35% of the paper backing 11; however, if the release agent used contains a solvent, excessive coating will cause the release agent to penetrate into the second side 112 of the paper backing 11. Therefore, it is preferred that the first penetration area 121 formed by the silicon release coating 12 on the first side 111 of the paper backing 11 does not exceed 50% of the paper backing 11, thereby avoiding the problem that the release agent penetrates into the opposite side and the opposite side cannot be coated.

[0023] Please refer to Figure 1The other side of the paper backing 11 opposite to the silicon release coating 12 includes a biodegradable water-based adhesive layer 13, which is formed on the second side 112 of the paper backing 11. In the present invention, the biodegradable water-based adhesive layer 13 of the biodegradable paper tape 1 is formed by directly coating the biodegradable water-based adhesive composition on the second side 112 of the paper backing 11. Since the paper backing 11 selected in the present invention is not coated with any coating, the biodegradable water-based adhesive composition will partially penetrate into the second side 112 of the paper backing 11. The second side 112 of the paper backing 11 is filled with a biodegradable water-based adhesive layer 13, and the biodegradable water-based adhesive layer 13 is formed on the second side 112 of the paper backing 11, and includes a second infiltration area 131 that overlaps with the paper backing 11 due to infiltration. In addition, it should be understood that since there is no other barrier material between the biodegradable water-based adhesive layer 13 and the second side 112 of the paper backing 11, the biodegradable water-based adhesive layer 13 is deemed to be directly formed on the second side 112 of the paper backing 11 and forms the second infiltration area 131. The biodegradable water-based adhesive layer 13 needs to be coated with a sufficient thickness and have a certain penetration amount in order to take into account both the adhesive performance and strength of the tape. In some embodiments of the present invention, the thickness of the biodegradable water-based adhesive layer 13 is preferably 15-20 μm, and the second penetration area 131 is controlled to occupy about one-third to one-quarter of the biodegradable water-based adhesive layer 13, and the second penetration area 131 is preferably not more than 10% of the thickness of the paper backing 11. For example, when the thickness of the paper backing 11 is 85 μm, the thickness of the biodegradable water-based adhesive layer 13 is preferably 15-20 μm, and the second penetration area 131 formed on the second side 112 is preferably about 5 μm, which accounts for about 5.88% of the thickness of the paper backing 11 and 1 / 3-1 / 4 of the overall thickness of the biodegradable water-based adhesive layer 13. In other words, there is still at least 10-15 μm (at least 66.7%) of the adhesive layer on the second side 112 of the paper backing 11, so that a good adhesion effect can be exerted, and its initial adhesion is at least greater than that of a No. 9 ball (tested according to GB / T 4582-2002), and the lasting adhesion is at least greater than 24 hours (tested according to GB / T4851-2014A). In addition, the total solid content of the biodegradable water-based adhesive composition used in the present invention is at least 60%. Therefore, the second infiltration area 131 formed by the biodegradable water-based adhesive layer 13 penetrating into the second side surface 112 of the paper backing 11 and overlapping therewith helps to strengthen the structural strength of the biodegradable paper tape 1. The tensile strength is at least greater than 50N / cm, the 180° peel strength (180° Peel Adhesion) tested by GBT2792-2014 is at least 2.5N / cm, and the ductility is at least maintained at a condition greater than 2%. Therefore, it can be seen that the biodegradable paper tape 1 obtained by the present invention not only maintains good bonding performance, but also has good structural strength.

[0024] The biodegradable water-based adhesive composition constituting the biodegradable water-based adhesive layer 13 may include a water-based acrylic adhesive and a polyurethane dispersant, and the total solid content of the biodegradable water-based adhesive composition is at least 60%, wherein the water-based acrylic adhesive includes a water-based random copolymer, and its monomer units are selected from one or more of acrylate, methacrylate, acrylic acid, methacrylic acid, acrylamide, and methacrylamide, and the polyurethane dispersant is a water-based anion-modified polyurethane dispersant. In some embodiments, the biodegradable water-based adhesive composition may further include a tackifier, and the tackifier may be selected from one or more of rosin resin, hydrogenated rosin resin, and terpene phenolic resin, among which an emulsion type tackifier is preferred, but not limited thereto. In addition, without affecting the adhesive properties and biodegradability of the biodegradable paper tape 1, the biodegradable adhesive composition 13 may also selectively include other additives, such as: colorants or other additives. The biodegradable paper tape 1 of the present invention has good biodegradability because the silicone release coating 12 and the biodegradable water-based adhesive layer 13 are directly formed on the two sides of the paper backing 11. The composting degradation rate measured according to GB / T19277.1 is at least greater than or equal to 90% in 180 days.

[0025] See also Figure 2 , which is a flow chart of making a biodegradable paper tape according to an embodiment of the present invention. Figure 2 As shown and considered Figure 1The process of making the biodegradable paper tape of the present invention comprises the following steps: providing a paper backing 11, wherein the paper backing 11 comprises a first side 111 and a second side 112 (step S1), providing a silicone release agent (step S2), coating the silicone release agent on the first side 111 of the paper backing 11, and partially infiltrating the first side of the paper backing 11 (step S3), drying the silicone release agent to form a silicone release coating 12 on the first side 111 of the paper backing 11, and the silicone release coating 12 further comprises a first infiltration area 121 infiltrating the first side 111 of the paper backing 11 (step S4), providing a biodegradable water-based adhesive composition, the total solid content of which is at least 60%, and comprises a water-based acrylic adhesive and a polyurethane dispersant (step S5), coating the biodegradable water-based adhesive composition on the second side 112 of the paper backing 11, and partially infiltrating the second side 112 of the paper backing 11 (step S6), and drying the biodegradable water-based adhesive composition to form a biodegradable water-based adhesive layer 13 on the second side 112 of the paper backing 11, the biodegradable water-based adhesive layer 13 including a second infiltration area 131 formed by the biodegradable water-based adhesive composition infiltrating the second side 112 of the paper backing 11 (step S7). However, it should be understood that there is no absolute order between the steps. For example, steps S1, S2, and S5 can be provided simultaneously or adjusted in sequence. In some embodiments, step S6 can be performed first to coat the biodegradable water-based adhesive composition on the paper backing 11 and step S7 can be performed to dry the composition, so as to first form a degradable bioadhesive layer on the second side of the paper backing, and then step S3 can be performed to coat the silicon release agent and step S4 can be performed to dry the release agent to form a silicon release coating on the first side of the paper backing. However, if the adhesive layer is formed first and then the release layer is formed, the adhesive layer must be attached to another release layer when the release agent is coated, so as to avoid the adhesive layers from adhering to each other, adhering to other objects, or being stained with dirt, dust, etc. Among these steps, only the cross-linking release agent must be directly cured after coating the release agent, and the biodegradable water-based adhesive composition must be directly dried after coating the biodegradable water-based adhesive composition. In other embodiments, if conditions permit, the release agent and the biodegradable water-based adhesive composition may be applied simultaneously, and then both are dried simultaneously to form a release layer and a biodegradable water-based adhesive layer. Each step will be further described below.

[0026] In this embodiment, the paper backing selected in step S1 is a kraft paper backing, and its thickness is between 80-90 μm, preferably 85 μm, so that the manufactured adhesive tape has good structural strength. The silicone release agent selected in step S2 can be a solvent-free silicone release agent, which can be applied by gravure coating or roller coating in step S3. In this embodiment, the viscosity of the solvent-free silicone release agent selected in step S2 at room temperature is at least 350 mPa·s, so a thin layer of silicone release agent can be applied on the first side of the paper backing. In the present invention, the thickness of the silicone release agent coating does not exceed 2 μm, and the thickness of the silicone release agent applied in this embodiment is about 2 μm. Since the paper backing used in the present invention does not have any coating layer or coating, the coated silicon release agent can partially penetrate into the first side, and the coated silicon release agent can be dried by hot air, and the drying temperature is preferably not less than 145°C to quickly dry the silicon release agent; and when the release agent used is a solvent-based release agent, the degree of its penetration into the first side of the paper backing can be controlled by adjusting and controlling the viscosity of the release agent, the drying temperature of the drying release agent, or the drying speed, and thus the proportion of the first penetration area can be controlled. When a solvent-based release agent is used, it is preferred that the first penetration area does not exceed 50% of the thickness of the paper backing to avoid the release agent penetrating into the other side of the paper backing (i.e., the second side) causing the biodegradable water-based adhesive composition to be unable to be coated, and when the selected silicon release agent is a solvent-free silicon release agent, the thickness of the silicon release layer formed does not exceed 2μm, and is preferably 1-2μm, so that the release effect and the production cost can be taken into account.

[0027] In this embodiment, the biodegradable water-based adhesive composition selected in step S5 includes a water-based acrylic adhesive and a polyurethane dispersant, and its solid content is at least 60%, so as to facilitate the control of the penetration of the biodegradable water-based adhesive composition; in addition, in order to increase the viscosity of the biodegradable water-based adhesive composition, in some embodiments, the biodegradable water-based adhesive composition further includes a thickener, and the selection of the selected water-based acrylic adhesive, polyurethane dispersant and thickener is as described above and will not be described in detail here. The biodegradable water-based adhesive composition applied in step S6 of the present embodiment has a thickness of about 44-72 μm. The coating method used is not limited, and can be a doctor blade coating method, a roller coating method, a blade coating method, a rod coating method, a spin coating method, a spray coating method, a die coating method, a gravure coating method, or a hand coating method, etc. Any method that can coat the adhesive on the backing film can be applied to the present case. Since the paper backing used in the present invention does not have any coating layer or coating, the applied biodegradable water-based adhesive composition will partially penetrate into the second side of the paper backing, and in step S7, it is dried and The second side of the paper backing forms a second penetration area, and the drying method can be infrared drying and hot air drying, but is not limited thereto. The overall thickness of the biodegradable water-based adhesive layer ranges from 15 to 20 μm, and the ratio of the second penetration area to the overall biodegradable water-based adhesive layer is 1:3 to 1:4 to ensure that there is enough adhesive on the surface of the paper backing. In addition, the second penetration area is preferably not more than 10% of the thickness of the paper backing, so as to utilize the second penetration area that penetrates into the second side of the paper backing to strengthen the structural strength of the paper backing, and to exert the adhesive effect by virtue of the adhesive layer remaining on the surface of the second side of the paper backing.

[0028] The following detailed description is intended to illustrate the present invention by way of example rather than limitation.

[0029] Table 1 shows the raw materials and sources used in the present invention.

[0030] Table 1 List of raw materials

[0031]

[0032] The raw materials described in Table 1 are used to prepare each adhesive combination according to the following Table 2 and the described proportions.

[0033] The raw materials of each group in Table 2 were mixed evenly with a small mixer (Thinky Mixer), and the thickness of Table 2 was coated on a 400mm*800mm kraft paper backing. Comparison 1 and Comparison 2 were coated on release paper by hand, and then transferred to 88μm and 90μm kraft paper backings respectively. The rest of the groups were coated on 85μm kraft paper backings with a lab coater. Infrared and step temperature were used, the first stage was not higher than 80 degrees drying, and then 100 degrees drying, and the coated biodegradable water-based adhesive was dried in a high-temperature oven to obtain each group of tape samples and ensure that the surface of the tape was smooth and flat. For details about the biodegradable water-based adhesive composition, please refer to Chinese Patent Application Publication No. 117264555A.

[0034] Table 2 Ratio of each component in each adhesive composition

[0035]

[0036] The following is the method for testing various properties of the adhesive tape of the present invention. The test results of the properties of each group of adhesive tape samples are shown in Table 3.

[0037] 180°Peel Adhesion

[0038] The peel strength of each group of tape samples was tested according to the national standard of the People's Republic of China GBT 2792-2014. A 24mm wide and 300mm long tape sample was adhered to a stainless steel plate for 20 minutes, and the stainless steel plate was fixed on the fixture of the tensile testing machine. Another fixture of the testing machine clamped the free end of the tape sample, formed an angle of 180° with the stainless steel plate, and pulled the tape sample apart at a specified speed to test the peel force required to separate the tape sample from the stainless steel plate.

[0039] Room Temperature Shear Force

[0040] The tape stickiness was tested according to the National Standard of the People's Republic of China GBT4851-2014 A. A 12 mm wide and 150 mm long tape sample was evenly adhered to a stainless steel plate with a roller, the free end of the tape sample was made vertical and a weight was applied to the free end, and the time required for the tape sample to separate from the stainless steel test plate was recorded.

[0041] Initial Tack

[0042] The initial adhesion of the tape sample is tested according to the National Standard of the People's Republic of China GB / T 4582-2002. Rolling balls of different sizes are placed on the adhesive surface of the tape on the inclined plate, and the initial adhesion is evaluated based on the maximum size of the steel ball that can be adhered to the adhesive surface of the specified length.

[0043] Tape tensile strength and elongation

[0044] According to the National Standard of the People's Republic of China GB / T30776-2014, the test method for tensile strength and elongation of tape is as follows: First, cut a specimen with a width of 25mm and a length of 150mm from the tape roll, ensuring that the specimen has no defects or damage. Use a tensile testing machine, ensure that the equipment is accurately calibrated, and set the clamp spacing to 100mm. Clamp the specimen at both ends in the upper and lower clamps of the tensile testing machine, ensuring that the specimen is vertical and without any slack. Stretch the specimen at a specified speed (usually 300mm / min) until the specimen breaks. Record the maximum tensile force (N) and elongation (mm) at the time of specimen break. The tensile strength is calculated by dividing the maximum tensile force (N) by the initial cross-sectional area of ​​the specimen (width × thickness, in mm²). The elongation is calculated by dividing the elongation (mm) at specimen break by the initial clamp spacing (100mm), and then multiplying by 100% to obtain the elongation as a percentage.

[0045] Degradation rate

[0046] The present invention adopts the National Standard of the People's Republic of China GB / T 19277.1-2011 "Determination of the final aerobic biodegradability of materials under controlled composting conditions using the test carbon dioxide method" to test the final aerobic biodegradability and disintegration degree of each tape sample under simulated strong aerobic composting conditions. Each tape sample is mixed with an inoculum and introduced into a static composting container. In the container, the mixture is strongly aerobic composted at a specified temperature, oxygen concentration and humidity. The biodegradation percentage is calculated using the formula specified in the standard.

[0047] Thickness of tape sample

[0048] The thickness of the adhesive tape is tested using the test method for adhesive tape thickness in the National Standard of the People's Republic of China GB / T 7125-2014. The thickness of the adhesive tape is obtained by deducting the thickness of the adhesive tape backing film from the measured thickness of the adhesive tape.

[0049] Table 3 Performance of each group of tape samples

[0050]

[0051] Generally speaking, whether the adhesive performance of a tape meets the requirements of use is mainly determined by three indicators: 180-degree peel strength, sustained adhesion and initial adhesion. The 180-degree peel strength reflects the adhesive strength of the material, and the peel strength of the sealing tape must be at least 0.25N / mm. The initial adhesion of the tape represents the ability of the tape to adhere to the attached object in a short contact time. The larger the test ball number in GB / T 4582-2002, the better the initial adhesion effect of the tape. From Table 3, it can be seen that although the final adhesive thickness reaches 20μm and the peel strength can reach the standard of 0.25N / mm, the second penetration area formed by the biodegradable water-based adhesive composition penetrating into the second side of the paper backing exceeds half of the total adhesive thickness, and the adhesive on the surface of the second side of the paper backing cannot exert sufficient persistent adhesion; and from Comparative Example 2, it can be seen that when the biodegradable water-based adhesive layer applied is increased, but because its second penetration area exceeds 60% of the total adhesive thickness, its persistent adhesion effect is not ideal, and the initial adhesion effect does not reach the 9-ball standard. Since Comparative Examples 1 and 2 did not reach the standard of sealing tape, the remaining experiments were not carried out with Comparative Examples 1 and 2.

[0052] Please refer to Table 3, Examples 1-7. When the thickness of the biodegradable water-based adhesive and the ratio of the second penetration area that penetrates into the paper backing to the overall biodegradable water-based adhesive layer are adjusted so that the adhesive layer is between 15-20 μm and the second penetration area accounts for 1 / 3-1 / 4 of the overall adhesive layer thickness, each group of Examples 1-7 can reach the standard of 180 degree peel strength greater than 0.25 N / mm; in addition, each group of Examples 1-7 can at least reach the standard of a No. 9 ball.

[0053] The higher the adhesiveness of the tape, the better the stickiness will last after the tape is completely attached to the object. For example, the adhesiveness requirement for packing tape is generally at least 1440 minutes, and as shown in Table 3, Experimental Examples 1-7 all show good stickiness. When the adhesive layer is increased to 25μm (such as Comparative Example 3) or even 28μm (such as Comparative Example 4), although its second penetration area is within the range of 1 / 3-1 / 4 of the overall adhesive thickness and has good 180-degree peel strength and initial adhesion, its stickiness cannot reach the standard of 1440 minutes.

[0054] In addition, as shown in Table 3, the degradation rate of the biodegradable paper tapes in Experimental Examples 1 to 6 is more than 90% in 180 days, and the tensile strength is at least 51.00N / cm. Since the tensile strength standard of the general international kraft paper tape is greater than or equal to 48N per 25mm (i.e. 19.2N / cm), and the tensile strength of easy-tear sealing tapes such as PE is at least 40.00N / cm, it can be seen that the biodegradable paper tapes prepared in Experimental Examples 1-7 can not only be used as general stationery tapes, but also have a tensile strength sufficient to be used as sealing tapes. The elongation of the biodegradable paper tapes in Experimental Examples 1 to 7 is at least 2.35%, which is also comparable to the elongation of general paper tapes (falling between 2.00-5.00%). It can be seen that the coating of the release agent and the adhesive will not affect the elongation of the paper backing, and the first and second infiltration areas formed by the infiltration of the release agent and the adhesive in the paper backing can further strengthen the structure of the paper backing.

[0055] In summary, the biodegradable paper tape disclosed in the present invention utilizes a biodegradable adhesive composition containing at least 60% solid components and controls the coating amount within a suitable range, so that the thickness of the final formed adhesive layer falls within 15-20 μm, and the second penetration area falls within 1 / 3-1 / 4 of the overall adhesive thickness (that is, the second penetration area on the paper backing surface is about 2-3 times the second penetration area), and the second penetration area of ​​the biodegradable adhesive layer is preferably no more than 10% of the thickness of the paper backing, thereby taking into account good tape performance and structural strength. The present invention also provides a biodegradable paper tape that is easy to prepare, wherein the coated biodegradable water-based adhesive composition is a non-solvent adhesive composition, and is therefore relatively environmentally friendly, and compared with hot melt adhesives or other adhesives extracted from biological components, it also has the advantage of being easy to prepare. When the coating amount and penetration amount of the biodegradable water-based adhesive composition are further controlled so that the thickness of the biodegradable water-based adhesive layer is between 15 and 20 μm and the second penetration zone formed by penetrating into the paper backing accounts for 1 / 3 to 1 / 4 of the overall adhesive thickness, the biodegradable paper tape can be ensured to have a good adhesion effect. It can not only be used as a writing, labeling, etc., but can also be used as a sealing tape. In addition, since the paper backing of the biodegradable paper tape provided by the present invention does not have any coating or barrier layer, it not only omits the cost of the coating or barrier layer, but is also conducive to biodegradation, and the paper tape structure can be further strengthened through the penetration of the release agent and the adhesive.

[0056] It will be appreciated by those skilled in the art that various modifications may be made to the above embodiments without departing from the basic principles of the invention. In addition, it will be apparent to those skilled in the art that various improvements and modifications may be made to the invention without departing from the spirit and scope of the invention.

Claims

1. A biodegradable paper tape, comprising: A paper backing, comprising a first side and a second side; a silicon release coating formed directly on the first side of the paper backing and comprising a first penetration region that partially penetrates into the first side of the paper backing; and A biodegradable water-based adhesive layer comprising: A water-based acrylic adhesive and a polyurethane dispersant, wherein the biodegradable water-based adhesive layer is directly formed on the second side of the paper backing and comprises a second penetration area, and the second penetration area partially penetrates into the second side of the paper backing; The initial adhesion of the biodegradable paper tape tested in accordance with GB / T 4582-2002 is at least equal to that of a No. 9 ball, and the sustained adhesion of the biodegradable paper tape tested in accordance with GBT4851-2014 A is at least greater than 24 hours.

2. The biodegradable paper tape according to claim 1, wherein the paper backing is a kraft paper backing.

3. The biodegradable paper tape according to claim 1, wherein the first penetration area of ​​the silicon release coating does not exceed 50% of the thickness of the paper backing, and the second penetration area does not exceed 10% of the thickness of the paper backing.

4. The biodegradable paper tape according to claim 1, wherein the water-based acrylic adhesive of the biodegradable water-based adhesive layer comprises a water-based random copolymer, and its monomer units are selected from one or more of acrylate, methacrylate, acrylic acid, methacrylic acid, acrylamide, and methacrylamide. 5 . The biodegradable paper tape according to claim 1 , wherein the polyurethane dispersant of the biodegradable water-based adhesive layer is an aqueous anion-modified polyurethane dispersant.

6. The biodegradable paper tape according to claim 1, wherein the biodegradable water-based adhesive layer further comprises a tackifier, and the tackifier is one or more selected from rosin resin, hydrogenated rosin resin, and terpene phenolic resin. 7 . The biodegradable paper tape according to claim 1 , wherein the biodegradable water-based adhesive layer has a thickness of 15-20 μm, and the second penetration zone occupies 1 / 3-1 / 4 of the biodegradable water-based adhesive layer.

8. The biodegradable paper tape according to claim 1, wherein the tensile strength thereof is at least greater than 50 N / cm as tested in accordance with GB / T 30776-2014, the 180° peel strength thereof is at least 2.5 N / cm as tested in accordance with GBT 2792-2014, and the ductility thereof is at least greater than 2%.

9. The biodegradable paper tape according to claim 1, wherein the biodegradability thereof is at least equal to or greater than 90% in a composting degradation rate in 180 days as measured by GB / T 19277.1-2011.

10. A method for producing a biodegradable paper tape, comprising: Providing a paper backing, the paper backing comprising a first side and a second side; Provide silicone release agent; Applying the silicon release agent to the first side of the paper backing, wherein the silicon release agent partially penetrates into the first side of the paper backing; Drying the silicon release agent to form a silicon release coating on the first side of the paper backing, wherein the silicon release coating includes a first penetration area that penetrates into the first side; A biodegradable water-based adhesive composition is provided, wherein the total solid content of the biodegradable water-based adhesive composition is at least 60% and comprises a water-based acrylic adhesive and a polyurethane dispersant; Applying the biodegradable water-based adhesive composition to the second side of the paper backing, wherein the biodegradable water-based adhesive composition partially penetrates into the second side of the paper backing; Drying the biodegradable water-based adhesive composition to form a biodegradable water-based adhesive layer on the second side of the paper backing, wherein the biodegradable water-based adhesive layer includes a second penetration area that penetrates into the second side; The initial adhesion of the biodegradable paper tape tested in accordance with GB / T 4582-2002 is at least equal to that of a No. 9 ball, and the sustained adhesion of the biodegradable paper tape tested in accordance with GBT4851-2014 A is at least greater than 24 hours.

11. The method for manufacturing a biodegradable paper tape according to claim 10, wherein the paper backing is a kraft paper backing. 12 . The method for producing a biodegradable paper tape according to claim 10 , wherein the silicone release agent is a solvent-free silicone release agent, and the viscosity of the silicone release agent at room temperature is at least 350 mPa·s. 13 . The method for manufacturing a biodegradable paper tape according to claim 10 , wherein the silicone release agent is coated on the first side of the paper backing by gravure coating or roller coating, and the coating thickness does not exceed 2 μm.

14. The method for manufacturing a biodegradable paper tape according to claim 10, wherein the silicone release agent is dried by hot air at a drying temperature not lower than 145°C.

15. The method for manufacturing a biodegradable paper tape according to claim 10, wherein the water-based acrylic adhesive of the biodegradable water-based adhesive composition comprises a water-based random copolymer, and its monomer units are selected from one or more of acrylate, methacrylate, acrylic acid, methacrylic acid, acrylamide, and methacrylamide. 16 . The method for producing a biodegradable paper tape according to claim 10 , wherein the polyurethane dispersant of the biodegradable aqueous adhesive composition is an aqueous anion-modified polyurethane dispersant.

17. The method for manufacturing a biodegradable paper tape according to claim 10, wherein the biodegradable water-based adhesive composition further comprises a tackifier, and the tackifier is one or more selected from rosin resin, hydrogenated rosin resin, and terpene phenolic resin.

18. The method for producing a biodegradable paper tape according to claim 10, wherein the biodegradable water-based adhesive composition is dried by infrared light and hot air.

19. The method for manufacturing a biodegradable paper tape according to claim 10, wherein the first penetration zone does not exceed 50% of the thickness of the paper backing, and the second penetration zone does not exceed 10% of the thickness of the paper backing. 20 . The method for manufacturing a biodegradable paper tape according to claim 10 , wherein the biodegradable water-based adhesive layer has a thickness of 15-20 μm, and the second penetration zone occupies 1 / 3-1 / 4 of the biodegradable water-based adhesive layer.

21. The method for manufacturing a biodegradable paper tape according to claim 10, wherein the biodegradable paper tape has a tensile strength of at least 50 N / cm as tested by GB / T 30776-2014, a 180° peel strength of at least 2.5 N / cm as tested by GBT 2792-2014, an ductility of at least 2%, and a biodegradability of at least 90% in 180 days as tested by GB / T 19277.1-2011.

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