Paper straw and preparation method thereof

Abstract

The embodiment of the invention provides a paper straw which comprises a straw body with a straw opening, the straw body comprises a straw opening part, the straw opening part is a local part comprising the straw opening, the straw opening part comprises a coating formed by coating liquid, a hydrophobic micro-interface is formed at the straw inlet part, liquid moisture is prevented from permeating into paper, and the paper can be prevented from permeating into the paper. The water resistance of the straw is remarkably improved, the service life of the straw is prolonged, meanwhile, the inlet part of the straw is smoother through the coating arranged on the straw opening part, friction between the straw and lips is reduced, the comfort degree during use is improved, the mouth sticking phenomenon is avoided, in addition, the hardness of the inlet part of the straw is enhanced through the coating arranged on the straw opening part, and the straw is not prone to deformation in the use process; the use amount of coating materials can be reduced to the maximum extent by only carrying out a local coating strategy on the straw opening part, the production cost is reduced, the market competitiveness is improved, and meanwhile, the invention provides a preparation method for preparing the paper straw.

Description

Technical Field

[0001] The invention relates to a paper straw and a preparation method thereof. Background Art

[0002] Currently, the use of disposable straws is huge. These disposable straws are usually made of plastic, but these plastic straws are difficult to degrade and have long-term impacts on soil and marine ecosystems. To solve this problem, paper straws have emerged as a more environmentally friendly alternative. However, existing paper straws have also exposed some problems during use: 1. Since the main component of paper straws is paper pulp, the fibers will absorb moisture when they come into contact with water, causing the straws to soften, deform, or even break. This seriously affects the normal use of paper straws, especially when drinking iced beverages or using them for a long time. The problem is more prominent.

[0003] Second, the rough surface of paper creates friction when in contact with the lips, affecting comfort. Paper straws are also weak, and the openings can be easily bitten or flattened, making them particularly vulnerable to damage when used by children.

[0004] Based on the above situation, users hope that paper straws can maintain good strength and shape during use, are not easy to soften or deform, and can meet the needs of long-term use. At the same time, they hope that the surface of the paper straws is smooth and feels comfortable when in contact with the lips, avoiding friction and paper scraps. Some improved solutions, such as CN114457618A, propose a method of applying a heat-resistant coating, and CN111531963A proposes a solution to the problem of maintaining the shape of the end in the form of a telescopic straw. However, these solutions still have defects in solving the above technical problems. On the other hand, these solutions are costly and lack market competitiveness. In addition, there is still a lack of consideration for cold drinks or iced drinks, making it difficult to meet the drinking needs of iced drinks, especially.

[0005] Therefore, a new technical solution is needed to solve the above technical problems. Summary of the Invention

[0006] The present invention provides a paper straw to solve the above technical problems.

[0007] A paper straw, comprising a tube body having a straw mouth, the tube body including a nozzle portion, the nozzle portion being a portion including the straw mouth, and comprising a coating formed of a coating liquid on the nozzle portion; The pipe mouth includes an inner wall, an outer part and an end face, and the coating covers the inner wall, the outer wall and the end face. The coating thickness at the end face is greater than the coating thickness at the inner wall and the outer wall.

[0008] Wherein, the length of the pipe mouth is 8 to 60 mm, and the length of the pipe mouth is less than 1 / 3 of the length of the tube body.

[0009] The present invention also provides a method for preparing the above-mentioned paper straws, which specifically comprises the following steps: S101: forming a tube body, wherein the tube body includes a straw opening; S102: immersing the nozzle portion into the coating liquid to form an immersion section, wherein the nozzle portion is the portion including the pipe opening; S103: Drying the tube body to form a paper straw, wherein the drying includes initial drying, middle drying and end drying. Initial drying: The tube body is dried by the first drying airflow flowing from the distal end toward the suction tube mouth. The temperature of the first drying airflow is 53-57°C. Middle drying: The tube body is dried by the second drying airflow perpendicular to the direction of the tube body. The temperature of the second drying airflow is 72-78℃. End drying: The tube body is dried by the third dry airflow flowing from the suction tube mouth to the distal end. The temperature of the third dry airflow is 93-97°C.

[0010] In step S102, the coating liquid uses one of acrylic resin, polyolefin resin, PLA, PHA water-emulsion coating or silane-modified coating as a main film-forming substance, and is dried in a microwave oven in step S103.

[0011] Wherein, in step S102, the coating liquid further includes a reinforcing agent and natural beeswax or palm wax emulsion.

[0012] Among them, the wind speeds of the first drying airflow, the second drying airflow and the third drying airflow increase in a stepwise manner, the wind speed of the first drying airflow is 2.5±0.2 m / s, the wind speed of the second drying airflow is 3.8±0.2 m / s, and the wind speed of the third drying airflow is 4.2±0.2 m / s.

[0013] Among them, in step S103, the initial drying time is 12 to 15 seconds, the middle drying time is 18 to 20 seconds, and the final drying time is 25 to 30 seconds. In step S102, the time including the pipe mouth being immersed in the coating liquid is 2 to 3 seconds.

[0014] In which, in step S102, an impregnation section is formed by an impregnation device, and the impregnation device includes a clamping conveying device and an impregnation tank, and the clamping conveying device includes a first conveyor belt and a second conveyor belt arranged relatively to each other, wherein the first conveyor belt includes a first abutting section, and the second conveyor belt includes a second abutting section, and the first abutting section and the second abutting section are arranged relative to each other and are configured to clamp the tube body, and the clamped tube body is in a vertical state.

[0015] Beneficial effects: An embodiment of the present invention provides a paper straw, which includes a tube body with a straw mouth, and the tube body includes a tube mouth portion, which is a part including the straw mouth, and the tube mouth portion includes a coating formed by a coating liquid. A hydrophobic micro-interface is formed at the entrance of the straw to prevent liquid moisture from penetrating into the interior of the paper, thereby significantly improving the waterproofness of the straw and extending its service life. At the same time, the coating provided at the tube mouth portion makes the entrance of the straw smoother, reduces friction with the lips, improves comfort during use, and avoids sticking to the mouth. In addition, the hardness of the entrance of the straw is enhanced by providing a coating at the tube mouth portion, so that it is not easy to deform during use, thereby improving durability, and the strategy of performing local coating only at the tube mouth portion can minimize the use of coating materials, reduce production costs, and improve market competitiveness. The present invention also provides a method for preparing the above-mentioned paper straws. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a manufacturing device for forming a tube body; Figure 2 It is a schematic diagram of the clamping and conveying device; Figure 3 is a schematic diagram of an impregnation device for forming an impregnation section; Figure 4 Schematic diagram of the drying process; Figure 5 Schematic diagram of the paper straw of the present invention; Description of components in the picture: Tube body 10; straw mouth 100; nozzle portion 101; end face 102; coating 103; impregnation portion 104; first paper tape 1001; second paper tape 1002; paper tube 1003; core shaft 11; roller 12; belt 13; clamping and conveying device 21; first conveyor belt 211; first abutting section 2111; isolation block 2112; negative pressure device 2113; second conveyor belt 212; second abutting section 2121; impregnation tank 22; coating liquid 23; liquid level 230. DETAILED DESCRIPTION

[0017] Please refer to Figure 5 An embodiment of the present invention provides a paper straw, which includes a tube body 10 having a straw mouth 100. The tube body 10 includes a nozzle portion 101. It can be understood that the nozzle portion 101 is a part including the straw mouth 100, and the nozzle portion 101 includes a coating 103 formed by a coating liquid 23.

[0018] As will be appreciated, the coating 103 should be water-repellent. By forming a hydrophobic microinterface at the straw entrance, it prevents liquid moisture from penetrating into the paper, significantly improving the straw's waterproofness and extending its service life. Furthermore, the coating 103 applied to the mouthpiece 101 makes the straw entrance smoother, reducing friction with the lips, enhancing comfort during use, and preventing sticking. Furthermore, the coating 103 applied to the mouthpiece 101 enhances the hardness of the straw entrance, making it less susceptible to deformation during use and improving durability. Furthermore, the strategy of applying a partial coating only at the mouthpiece 101 minimizes the amount of coating material used, reduces production costs, and improves market competitiveness.

[0019] To facilitate understanding of the present invention, the preparation method of the paper straw will be further described below.

[0020] S101 : forming a tube body 10 , wherein the tube body 10 includes a straw mouth 100 .

[0021] Please refer to Figure 1 ,exist Figure 1 , a manufacturing device for forming the tube body 10 is shown, and the manufacturing device includes a winding part and a slitting part which are arranged in sequence.

[0022] The winding portion is used to wind the first paper tape 1001 and the second paper tape 1002 to form a continuous paper roll 1003. The winding portion includes a core shaft 11 and a driving device. The driving device is configured to drive the first paper tape 1001 and the second paper tape 1002 to rotate and wind on the core shaft 11 to form a tubular paper roll 1003, and at the same time drive the paper roll 1003 to slide downstream along the axis of the core shaft 11.

[0023] The core shaft 11 is roughly in the shape of a cylindrical rod, and the driving device includes a pair of rollers 12 and a belt 13 wound on the pair of rollers 12. The belt 13 is driven by the pair of rollers 12. At least a portion of the first belt 13 is wound on the core shaft 11 at an inclined angle. The first paper tape 1001 and the second paper tape 1002 enter and are wound on the core shaft 11 at a predetermined inclined angle, and the portion of the belt 13 wound on the core shaft 11 winds up and presses the first paper tape 1001 and the second paper tape 1002. It can be understood that when the belt 13 is wound on the core shaft 11, the first paper tape 1001 and the second paper tape 1002 are wound on the core shaft 11. When the belt 13 moves under the drive of the roller 12, the first paper tape 1001 and the second paper tape 1002 will be spirally wound along the axial direction of the core shaft 11 and form a paper tube 1003. It can be understood that the first paper tape 1001 forms a first paper layer, and the second paper tape 1002 forms a second paper layer. The first paper tape 1001 and the second paper tape 1002 are stacked, and the first paper tape 1001 is located above the second paper tape 1002, so that the first paper layer is located on the outside and the second paper layer is located on the inside. The side wall is the side wall of the paper tube 1003.

[0024] Since the belt 13 and the first and second paper tapes 1001, 1002 are all wound on the core shaft 11 at a certain inclination angle, driven by the belt 13, the first and second paper tapes 1001, 1002 are spirally wound along the axial direction of the core shaft 11 to form the paper tube 1003, and at the same time, they will also slide from one end of the core shaft 11 to the other end along the axial direction of the core shaft 11, and finally slide out.

[0025] In this embodiment, the first paper tape 1001 and the second paper tape 1002 are fed from the left side, and after being wound to form the paper roll 1003, the formed paper roll 1003 is from left to right.

[0026] The inner side of the second paper tape 1002 is wound around the outer wall of the core shaft 11. At the same time, the outer side of the second paper tape 1002 is also coated with adhesive. The first paper tape 1001 is wound around and bonded to the second paper tape 1002 through the adhesive. The first paper tape 1001 and the second paper tape 1002 move synchronously during the winding process, so that the formed paper tube 1003 has a stable structure.

[0027] The slitting portion is used to slit the continuous paper roll 1003 formed by the winding portion to form a tube body 10. It can be understood that the tube body 10 formed after slitting includes a straw opening 100. More specifically, a straw opening 100 is formed on each of the two adjacent sections of the tube body 10 after slitting.

[0028] It can be understood that the slitting portion includes a cutter. In addition, when the paper tube 1003 is cut by the cutter, the core shaft 11 can also provide internal support and positioning for the cutting, thereby facilitating the cutting.

[0029] Furthermore, a separation section may be provided downstream of the slitting section to separate adjacent cylinders to facilitate operations such as conveying the cylinders. Typically, the separation section includes a plurality of separation rollers, each of which forms a support surface on which the cylinders are supported. The speed of the downstream separation rollers is greater than that of the upstream separation rollers, thereby separating adjacent cylinders and forming a gap.

[0030] S102 : Immerse the nozzle portion 101 including the straw nozzle 100 in the coating liquid 23 to form an immersed portion 104 .

[0031] It can be understood that the length of the nozzle portion 101 is 8 to 60 mm, and the length of the formed impregnation portion 104 is 8 to 60 mm, so that the finally formed coating 103 has a length of 8 to 60 mm. The length of the nozzle portion 101 refers to the length from the end face 102 of the straw mouth 100 to the end of the coating 103 away from the end face. At this length, the user's mouth can conveniently hold the nozzle portion 101 to avoid the mouth from contacting the non-coated area. In another embodiment, the length of the nozzle portion 101 should be less than 1 / 3 of the length of the tube body 10.

[0032] It can be understood that the coating liquid 23 can include acrylic resin, PLA, PHA water-emulsion coating or silane-modified coating. The acrylic resin can be Michem9100, and the silane-modified coating can be silane-modified acrylic / polyether polymer, more specifically Papkot silane-modified coating.

[0033] In another embodiment, the coating liquid 23 includes: acrylic resin polymer, plasticizer, reinforcing agent and natural beeswax or palm wax emulsion. The acrylic resin polymer and the plasticizer form a film, the reinforcing agent strengthens the coating and paper, and the wax forms a water-repellent effect. It can also include a defoaming agent and a wetting agent. In a specific embodiment, the coating liquid 23 includes: 60-70% water-based acrylic resin; 10-15% citrate plasticizer; 3-5% nanocellulose; 8-12% natural beeswax or palm wax emulsion; 0.1-0.3% defoaming agent; and 0.3-0.8% wetting agent.

[0034] In another embodiment, the water-based acrylic resin may also be polyurethane, styrene-butadiene resin, or other acrylic resin polymers.

[0035] Furthermore, the defoaming agent is a silicone defoaming agent, and the wetting agent is a polyether-modified siloxane. The defoaming agent is added to reduce coating bubbles and ensure uniformity, and the wetting agent is added to improve the leveling of the coating.

[0036] In a specific embodiment, the coating liquid 23 can also be the coating material shown in CN113891901A. Specifically, the coating liquid contains (B) an aqueous emulsion obtained by polymerizing (b) a polymerizable unsaturated monomer in the presence of (A) a copolymer having a carboxyl group, wherein the polymerizable unsaturated monomer (b) contains (b1) (meth)acrylate, and based on 100 parts by mass of the total mass of the polymerizable unsaturated monomer (b), the content of the (meth)acrylate (b1) exceeds 95 parts by mass.

[0037] The copolymer (A) having a carboxyl group serves as a stabilizer when polymerizing the polymerizable unsaturated monomer (b) to prepare the aqueous emulsion (B), and the copolymer (A) having a carboxyl group is a synthetic resin having a carboxyl group that can be obtained by polymerizing at least one selected from (meth)acrylic acid and (meth)acrylate.

[0038] The aqueous emulsion (B) can be obtained by polymerizing (b) a polymerizable unsaturated monomer in the presence of the copolymer (A) having a carboxyl group. Preferably, the copolymer contained in the aqueous emulsion (B) can be obtained by polymerizing n-butyl acrylate or 2-ethylhexyl acrylate with one or more other monomers.

[0039] The (meth)acrylate may be: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, octadecyl (meth)acrylate, behenyl (meth)acrylate and behenyl (meth)acrylate; and hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

[0040] Please refer to Figure 3 ,exist Figure 3 , an impregnation device for forming the impregnation portion 104 is shown. The impregnation device includes a clamping and conveying device 21 and an impregnation tank 22 .

[0041] Please refer to Figure 2 ,exist Figure 2The figure shows a top view of the clamping and conveying device 21 clamping the tube body 10, wherein the clamping and conveying device 21 comprises a first conveyor belt 211 and a second conveyor belt 212 arranged opposite to each other, wherein the first conveyor belt 211 comprises a first abutting section 2111, and the second conveyor belt 212 comprises a second abutting section 2121, and the first abutting section 2111 and the second abutting section 2121 are arranged relative to each other and are configured to clamp the tube body 10. It can be understood that the clamped tube body 10 is in a vertical state, and the part including the straw mouth 100 is located on the lower side and is exposed. For the convenience of description, the part including the straw mouth 100 is referred to as the tube mouth portion 101.

[0042] The immersion tank 22 is arranged on the lower side of the clamping and conveying device 21, and the coating liquid 23 is contained in the immersion tank 22 and forms a liquid surface 230. The tube body 10 is configured so that when passing through the immersion tank 22, the tube mouth 101 is immersed below the liquid surface 230, so that the tube mouth 101 is immersed in the coating liquid 23.

[0043] Furthermore, the first conveyor belt 211 and the second conveyor belt 212 move in opposite directions and at the same speed, so that the tube body 10 can be stably clamped and conveyed.

[0044] Furthermore, the clamping and conveying device 21 also includes a negative pressure device 2113, the first conveyor belt 211 includes a plurality of through holes, the first abutting section 2111 includes a first abutting surface, and the negative pressure device 2113 is configured to form a negative pressure state in an area adjacent to the first abutting surface, so that the tube body 10 is adsorbed on the first abutting surface, that is, when the second conveyor belt 212 unexpectedly fails to apply a clamping force, the tube body 10 can still be maintained on the first abutting surface by the action of negative pressure, thereby preventing it from unexpectedly falling into the immersion tank 22.

[0045] Furthermore, the first conveyor belt 211 further includes isolation blocks 2112 for allowing the tubes 10 to be arranged at equal intervals on the first abutting section 2111 .

[0046] Furthermore, the nozzle portion 101 is immersed in the coating liquid 23 for 2 to 3 seconds.

[0047] Furthermore, the coating liquid 23 has a dynamic viscosity of 300 to 500 mPa·s.

[0048] S103: Dry the tube body 10 to form a paper straw.

[0049] Specifically, when the coating liquid is one of Michem9100, PLA, PHA water-emulsion coating, and Papkot silane-modified coating, the drying is performed in a microwave oven.

[0050] Specifically, the tube body 10 is subjected to initial drying, middle drying, and terminal drying to form a paper straw, wherein: Initial drying: The tube body 10 is dried by a first drying airflow flowing from the distal end toward the suction tube opening 100. The temperature of the first drying airflow is 53-57°C. Middle drying: The tube body 10 is dried by a second drying airflow perpendicular to the direction of the tube body 10, and the temperature of the second drying airflow is 72-78°C; End drying: The tube body 10 is dried by the third drying airflow flowing from the suction pipe opening 100 to the distal end. The temperature of the third drying airflow is 93-97°C.

[0051] Please refer to Figure 4 and Figure 5 In this embodiment, the tube body 10 is vertically arranged with the straw opening 100 located at the bottom, and the distal end is upward and opposite to the straw opening 100. The first drying airflow flows from top to bottom, the second drying airflow flows horizontally, and the third drying airflow flows from bottom to top. Research has found that the use of the above-mentioned coating liquid 23 and the above-mentioned drying method produces the following effects: 1. When materials such as beeswax are used in the coating liquid 23, a low temperature is used in the initial drying stage to promote and ensure that the wax crystals form an oriented arrangement; Second, the initial drying stage uses a first drying airflow flowing from top to bottom. On the one hand, it can limit the upward infiltration of the coating liquid 23 along the tube wall. On the other hand, it can make the coating liquid 23 evenly distributed on the tube wall. Third, the top-down airflow combined with the gravity of the coating liquid can form a thicker impregnation layer on the end face 102 of the suction pipe mouth 100 located directly below, thereby forming a thicker coating 103 on the end face 102. Fourth, it can ensure the smooth flow of the internal channel of the tube body 10.

[0052] 3. The second dry airflow at 72-78°C triggers the film to become continuous, while the third dry airflow at 93-97°C promotes the cross-linking of the citrate plasticizer and the nanocellulose to form a stable coating 103.

[0053] Fourth, the high-temperature third dry airflow flows from bottom to top, which, on the one hand, makes the surface of the coating 103 smooth, and on the other hand, blows the coating 103 formed on the end face of the straw mouth 100 to prevent the coating at the end face from forming sharp corners under the action of gravity. At the same time, the connection between the coating on the tube wall and the coating on the end face forms a rounded transition, thereby improving user comfort.

[0054] Further research found that when the acrylic acid / beeswax blend system is matched with the above-mentioned three-step gradient drying design, the paper straws' protection against saliva is improved by more than 50% compared to untreated paper straws, and for low-temperature beverages at 1-5°C, the protection is improved by more than 45%. In addition, compared with full coating or lamination treatment, the cost is reduced by 18.2% and 33.1% respectively.

[0055] Furthermore, the nanocellulose has a diameter of 50 to 100 nm and an aspect ratio greater than 50. By using the nanocellulose, the coating 103 formed by the coating liquid 23 has higher strength and forms a dense structure.

[0056] Furthermore, the wind speeds of the first drying airflow, the second drying airflow and the third drying airflow are increased in stages, so as to reduce the loss of the coating liquid 23 on the surface of the tube body 10 and accelerate the drying by increasing the wind speed in stages. Specifically, the wind speed of the first drying airflow is 2.5±0.2m / s, the wind speed of the second drying airflow is 3.8±0.2m / s, and the wind speed of the third drying airflow is 4.2±0.2m / s.

[0057] Furthermore, the initial drying time is 12 to 15 seconds, the middle drying time is 18 to 20 seconds, and the final drying time is 25 to 30 seconds.

[0058] Furthermore, during the mid-stage drying, the paper straw rotates.

[0059] Furthermore, the pipe mouth 101 includes an inner wall, an outer wall and an end face, and the coating covers the inner wall, the outer wall and the end face. The inner wall is the side wall of the pipe mouth facing the through hole of the tube body 10, and the outer wall is the side wall of the pipe mouth facing away from the through hole. The end face connects the inner wall and the outer wall.

[0060] Furthermore, the coating thickness on the end surface is greater than the coating thickness on the inner sidewall and the outer sidewall.

[0061] Furthermore, in another embodiment, after step S103, the following steps are further included: S104: A step of applying an outer layer on the coating layer 103 and drying the coating layer.

[0062] The coated outer layer can be evenly coated to further enhance the waterproof performance and make the outer surface smooth.

[0063] At the same time, the outer layer can be dried by microwave drying.

[0064] Furthermore, both straw openings of the paper straw are provided with a coating, and the two coatings are arranged at intervals. In this case, after step S103, the arrangement further includes flipping the tube body, immersing the flipped tube body in the coating liquid and drying it.

[0065] The following is further described with reference to specific embodiments.

[0066] Example 1: S201: forming a tube body 10, wherein the tube body 10 includes a straw mouth 100, and the diameter of the tube body 10 is 8 mm.

[0067] S202: The portion including the pipette mouth 100 is immersed in the coating liquid 23 to form an immersed portion 104. The immersed portion 104 (i.e., the pipe mouth 101) is 12 mm in diameter. The coating liquid 23 comprises: 64% aqueous acrylic resin; 13% citrate plasticizer; 4% nanocellulose (diameter 77 nm, aspect ratio 69); 10% natural beeswax; 0.1% silicone defoamer; 0.4% polyether-modified siloxane wetting agent; and the remainder is deionized water. The dynamic viscosity is 405 mPa·s.

[0068] S203: The tube body 10 is subjected to initial drying, middle drying, and terminal drying to form a paper straw, wherein: Initial drying: The tube body 10 is dried by a first drying airflow flowing from the distal end toward the suction pipe opening 100. The first drying airflow temperature is 55°C, the wind speed is 2.6±0.1m / s, the drying time is 14s, and the airflow turbulence intensity is 6%. Mid-section drying: The tube body 10 is dried by a second drying airflow perpendicular to the direction of the tube body 10. The temperature of the second drying airflow is 75°C, the wind speed is 3.9±0.1m / s, the drying time is 19s, and the airflow turbulence intensity is 10%. End drying: The tube body 10 is dried by the third dry airflow flowing from the suction pipe mouth 100 to the distal end. The third dry airflow temperature is 95°C, the wind speed is 4.2±0.1m / s, the drying time is 28s, and the airflow turbulence intensity is 8%.

[0069] Comparative Example 1: The tube body 10 formed in step S201 is not processed in steps S202 and S203.

[0070] Test method: Saliva resistance: Ten paper straws were immersed in artificial saliva (GB / T 18886-2019, pH 6.8) with the mouth 100° at the end. The soaked portion of the straws was observed for any curling, delamination, or cracking greater than 2 mm. The time taken to observe the cracks was recorded and the average value was taken.

[0071] Resistance to low-temperature solutions: Take 10 paper straw samples and immerse one end of the straw mouth at 100° in 2-4°C deionized water. Observe the part of the sample soaked in liquid. If there is any warping, delamination or cracking greater than 2mm, record the time and take the average value.

[0072] It can be seen that the paper straws prepared using the preparation method of the present invention have saliva resistance improved by 51.6%, and low-temperature solution resistance improved by 47.5%.

[0073] The above description is only an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A paper straw, characterized in that: The paper straw includes a tube body having a straw mouth, wherein the tube body includes a nozzle portion, wherein the nozzle portion is a portion including the straw mouth, and the nozzle portion includes a coating formed by a coating liquid; The pipe mouth includes an inner wall, an outer part and an end face, and the coating covers the inner wall, the outer wall and the end face. The coating thickness at the end face is greater than the coating thickness at the inner wall and the outer wall.

2. The paper straw according to claim 1, wherein: The length of the pipe mouth is 8 to 60 mm, and the length of the pipe mouth is less than 1 / 3 of the length of the pipe body.

3. A method for preparing the paper straw according to claim 1, characterized in that: The steps include: S101: forming a tube body, wherein the tube body includes a straw opening; S102: immersing the nozzle portion into the coating liquid to form an immersion section, wherein the nozzle portion is the portion including the pipe opening; S103: Drying the tube body to form a paper straw, wherein the drying includes initial drying, middle drying and end drying. Initial drying: The tube body is dried by the first drying airflow flowing from the distal end toward the suction tube mouth. The temperature of the first drying airflow is 53-57°C. Middle drying: The tube body is dried by the second drying airflow perpendicular to the direction of the tube body. The temperature of the second drying airflow is 72-78℃. End drying: The tube body is dried by the third dry airflow flowing from the suction tube mouth to the distal end. The temperature of the third dry airflow is 93-97°C.

4. The preparation method according to claim 4, wherein In step S102, the coating liquid uses one of acrylic resin, polyolefin resin, PLA, PHA water-emulsion coating or silane-modified coating as a main film-forming substance, and is dried in a microwave oven in step S103.

5. The preparation method according to claim 4, wherein In step S102, the coating liquid further includes a reinforcing agent and natural beeswax or palm wax emulsion.

6. The preparation method according to claim 6, wherein The wind speeds of the first drying airflow, the second drying airflow and the third drying airflow increase in a stepwise manner. The wind speed of the first drying airflow is 2.5±0.2 m / s, the wind speed of the second drying airflow is 3.8±0.2 m / s, and the wind speed of the third drying airflow is 4.2±0.2 m / s.

7. The preparation method according to claim 7, wherein In step S103, the initial drying time is 12 to 15 seconds, the middle drying time is 18 to 20 seconds, and the final drying time is 25 to 30 seconds. In step S102, the time including the nozzle is immersed in the coating liquid is 2 to 3 seconds.

8. The preparation method according to claim 4, wherein In step S102, an impregnation section is formed by an impregnation device, wherein the impregnation device includes a clamping conveying device and an impregnation tank, and the clamping conveying device includes a first conveyor belt and a second conveyor belt arranged opposite to each other, wherein the first conveyor belt includes a first abutting section, and the second conveyor belt includes a second abutting section, and the first abutting section and the second abutting section are arranged relative to each other and are configured to clamp the tube body, and the clamped tube body is in a vertical state.

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