Straw and preparation method thereof

Abstract

The invention discloses a straw and a preparation method thereof, and the straw comprises at least one bamboo belt layer which is a first pipe body formed by winding a bamboo belt; the bamboo belts are formed by machining raw bamboos; the paper tape layer comprises a paper tape, and the paper tape is attached to at least part of the surface of the first tube body. The preparation method comprises the following steps: a bamboo band layer forming step: spirally winding a bamboo band into a bamboo band layer; and a paper tape layer forming step: spirally winding the paper tape to form the paper tape layer. The bamboo belt is wound to form the bamboo belt layer to serve as a structural supporting layer of the straw, and the problem that a paper straw is prone to softening is solved; meanwhile, the paper tape layer is attached to the bamboo tape layer, the bamboo tape layer is reinforced through the toughness of the paper tape, and the problem that the bamboo straw is poor in tensile property and torsion resistance is solved; in addition, compared with a pure bamboo straw, the bamboo paper straw disclosed by the invention has the advantages that the use amount of bamboo belts in the straw is reduced, the paper belts are attached to the bamboo belts, the manufacturing difficulty is reduced, and meanwhile, the production cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of straw processing, and particularly to a straw and a preparation method thereof. Background Art

[0002] With the increasingly serious problem of plastic pollution, plastic waste has caused irreparable damage to the earth's ecosystem. As an item frequently used daily, the plastic waste generated after the abandonment of disposable plastic straws has exacerbated environmental pollution. Therefore, many countries and regions have begun to impose restrictions on traditional plastic straws, or even a complete ban.

[0003] In this context, the market demand for environmentally friendly and biodegradable straw products is increasing day by day. Since PLA (polylactic acid) materials are prepared based on biological materials and have the advantage of being degradable, PLA straws have gradually been pushed to the forefront of the market and quickly become a substitute for plastic straws. However, with the use of PLA straws, their disadvantages have gradually emerged; firstly, their degradation process is not as rapid as advertised in the market and requires specific conditions and time, which means that they still remain in many environments for a long time and cannot be degraded; secondly, the heat resistance and water resistance of PLA materials are poor. When they are used in hot drinks or soaked in liquids for too long, the PLA straws will become deformed and softened, which seriously affects the user experience.

[0004] To meet the market demand, pure paper straws have emerged. Since paper materials naturally have the characteristics of biodegradability and are environmentally friendly, they have gradually become the main material for straws. However, they also have a huge defect, that is, when soaked in liquid for a slightly longer time, the paper straws will soften, reducing the user experience.

[0005] On the other hand, bamboo, as a material with a fast regeneration rate and biodegradability, has gradually been applied to the manufacture of straws. For example, the production process of wound bamboo straws disclosed in Chinese Patent ZL202110538234.1. However, due to the characteristics of bamboo materials, their toughness is poor. Without chemical process treatment, fine control is required in production and processing to reduce the waste rate during the manufacturing process. At the same time, due to the winding production method, it is required to control the tensile strength and torsional resistance of pure bamboo straws, otherwise they are prone to cracking during use. Summary of the Invention

[0006] The technical problems to be solved by the present invention at least include: how to improve the tensile strength and / or torsional resistance of bamboo straws to avoid cracking problems during use.

[0007] To solve the above technical problems, the present invention creatively introduces a paper material with higher tensile strength, combines bamboo and paper materials, and develops a composite straw that can ensure the structural stability and user experience of the straw while also ensuring its environmental protection and biodegradability performance. The specific technical solution adopted is as follows:

[0008] A straw, comprising:

[0009] At least one bamboo strip layer, the bamboo strip layer being a first tube body formed by winding bamboo strips; the bamboo strips being formed by mechanically processing raw bamboo;

[0010] At least one paper strip layer, the paper strip layer including paper strips, the paper strips being attached to at least a part of the surface of the first tube body.

[0011] Another technical solution adopted by the present invention to solve the above technical problems is as follows:

[0012] A method for preparing a straw, comprising:

[0013] A bamboo strip layer forming step of winding bamboo strips into a bamboo strip layer; the bamboo strips being formed by mechanically processing raw bamboo;

[0014] And a paper strip layer forming step of winding paper strips to form a paper strip layer;

[0015] The paper strips being attached to at least a part of the surface of the bamboo strip layer.

[0016] The beneficial effects of the present invention are as follows: A straw and a method for preparing the same are provided. By mechanically processing raw bamboo into bamboo strips and winding the bamboo strips to form a bamboo strip layer as the structural support layer of the straw, the problem of easy softening of paper straws is solved; at the same time, a paper strip layer is attached to the bamboo strip layer, and the toughness of the paper strips themselves is used to strengthen the bamboo strip layer, solving the problem of poor tensile and torsional resistance of bamboo straws; in addition, compared with pure bamboo straws, the bamboo paper straws disclosed in the present invention reduce the usage amount of bamboo strips in the straws, use paper strips attached to bamboo strips, reduce the manufacturing difficulty, and the product qualification rate reaches more than 99%, saving production costs. Description of the Drawings

[0017] Figure 1 A schematic diagram of a straw in Embodiment 1 of the present invention;

[0018] Figure 2 A schematic diagram of another straw in Embodiment 1 of the present invention;

[0019] Figure 3 A schematic diagram of a straw in Embodiment 2 of the present invention;

[0020] Figure 4 For Figure 3 A cross-sectional view of a straw in

[0021] Label description:

[0022] 1. Bamboo strip layer; 2. Paper strip layer; 3. Bamboo strip; 4. Paper strip. Specific implementation mode

[0023] To describe in detail the technical content, achieved purpose and effects of the present invention, the following is described in conjunction with the implementation modes and with reference to the accompanying drawings.

[0024] Please refer to Figures 1 to 4 , the present invention discloses a straw, including a first tube body formed by bamboo strips and a second tube body formed by paper strips, and the first tube body and the second tube body are attached to each other.

[0025] In some embodiments, the above attachment setting may specifically be that there is an adhesive layer between the first tube body and the second tube body.

[0026] It should be noted that the first tube body may be a tubular body formed by bamboo strips in a tightly continuous form, or may be a tubular body formed by bamboo strips in a sparse or gap-forming form; similarly, the second tube body may be a tubular body formed by paper strips in a tightly continuous form, or may be a tubular body formed by paper strips in a sparse or gap-forming form. Those skilled in the art can understand that after the first tubular body and the second tubular body are combined to form a straw, the straw as a whole has a flow channel for fluid to flow through.

[0027] In some embodiments, a straw is provided, including at least one bamboo strip layer, the bamboo strip layer being a first tube body formed by bamboo strips; at least one paper strip layer, the paper strip layer being a second tube body formed by paper strips; and there is an adhesive layer between the first tube body and the second tube body. The tube body can be formed by winding. Specifically, the bamboo strips are wound to form the first tube body; the paper strips are wound to form the second tube body.

[0028] The present invention further discloses a straw, including:

[0029] At least one bamboo strip layer 1, the bamboo strip layer 1 being a tube body wound by bamboo strips 3; the bamboo strips 3 are formed by mechanically processing raw bamboo;

[0030] At least one paper strip layer 2, the paper strip layer 2 including paper strips 4, and the paper strips 4 are attached to at least part of the surface of the bamboo strip layer 1.

[0031] Among them, the winding forms include spiral winding, horizontal winding, cross winding, etc., and the specific winding method is selected according to production conditions and expected effects.

[0032] Based on general knowledge, raw bamboo refers to bamboo growing in nature, rather than bamboo fibers extracted through multiple chemical process steps. Since raw bamboo itself has waterproof properties, the bamboo strips formed after cutting raw bamboo have excellent waterproof performance. Compared with composite materials made of pulp or bamboo fiber pulp, there is no need to add kraft paper or other waterproof measures. Generally speaking, cutting raw bamboo includes various processing methods. For example, in the embodiments of the present invention, after cutting a raw bamboo section into bamboo slices, mechanical processing is carried out along the fiber direction of the bamboo slices to form bamboo strips. It should be noted that according to common understanding, the shape of a bamboo strip refers to an elongated object whose length is much greater than its width and thickness. As an example, the dimensions of the bamboo strip can be a length of 2 - 400 m, a width of 10 - 20 mm, and a thickness of 0.25 - 1 mm. Preferably, the bamboo strip can be 300 m in length, 15 mm in width, and 0.25 mm in thickness.

[0033] The paper tape adheres to a partial surface of the bamboo strip layer, that is, the connection relationship between the paper tape and the bamboo strip layer is close adhesion and fixation. Specifically, the adhesion includes, but is not limited to, forms such as internal gluing and external sealing. It should be noted that the so-called paper tape is usually made by surface treating and then processing and cutting raw wood pulp. In the field of paper straws, for example, the paper tape is obtained by modifying raw wood pulp into kraft paper and then cutting it.

[0034] The bamboo strip at least includes: a strip-shaped object cut from one end of the bamboo slice along the fiber direction of the bamboo to the other end. The thickness range of the bamboo strip in the embodiments of the present invention is 0.25 mm - 0.5 mm.

[0035] The paper tape at least includes a strip-shaped object cut from kraft paper, food-grade coated paper, reinforced paper, etc. Further, in some embodiments of the present invention, the thickness range of the paper tape is 60 - 220 g / cm 2 。

[0036] From the above description, the beneficial effects of the present invention are as follows: By mechanically processing raw bamboo into bamboo strips and winding the bamboo strips 3 to form a bamboo strip layer 1 as the structural support layer of the straw, the problem of easy softening of paper straws is solved; at the same time, a paper tape layer 2 is attached to the bamboo strip layer 1, and the toughness of the paper tape 4 itself is used to strengthen the bamboo strip layer 1, solving the problems of poor tensile and torsional resistance of bamboo straws; in addition, compared with pure bamboo straws, the bamboo paper straw disclosed in the present invention reduces the usage amount of the bamboo strip 3 in the straw, and by attaching the paper tape 4 to the bamboo strip 3, the manufacturing difficulty is reduced, the yield rate reaches more than 99%, and the production cost is saved.

[0037] In some embodiments of the present invention, the paper tape layer 2 is a second tube body formed by winding the paper tape 4.

[0038] As can be seen from the above description, in order to strengthen the overall strength of the straw, the paper tape layer 2 and the bamboo tape layer 1 are both formed by winding. The wound paper tape layer 2 adheres to the bamboo tape layer 1. The winding form enables the paper tape layer to disperse among the wound layers when bearing torsion, reducing the negative effect of stress concentration, thereby improving the anti-torsion performance of the straw. Specifically, the winding body of the paper tape itself forms a radial constraint on the bamboo tape winding body, reducing the torsion borne by the bamboo tape due to bending. During the R & D process, the inventor found that for the analysis of scrap products of all-bamboo straws, especially bamboo tape straws directly processed from raw bamboo, it often resorts to visible defects in the bamboo tape processing process. The inventor found that in special cases, even without obvious visible defects, there is still a certain probability of failure risk during or after the winding of the bamboo tape. Research shows that microcrack defects may be formed during the bamboo tape processing process, resulting in stress concentration and possible potential cracking points, which do not show up in the form of cracking and fracture in the initial stage of winding. This stress concentration may only become apparent after the processed product is made, during storage and transportation, or during use. For such cases where the product is qualified initially but deteriorates later, producers often have no way to discover and deal with them. Based on the discovery and tracing of this problem, the inventor introduced the paper tape layer into the structure of the bamboo straw in a winding form, successfully and effectively reducing the longitudinal tensile stress in the bamboo tape, effectively reducing stress concentration, further reducing risks such as cracking and fracture, reducing the failure risk of the straw, and improving the yield rate of the straw.

[0039] In some embodiments of the present invention, the adjacent layers of the wound paper tape 4 are laminated.

[0040] As can be seen from the above description, in order to reduce the manufacturing difficulty and considering the relatively soft texture of the paper tape 4, the paper tape layer 2 is formed by laminating adjacent layers of the paper tape 4. At the same time, the paper tape layer 2 with adjacent layers laminated layer by layer has better waterproof performance than the joint structure. In addition, the wound layers of the paper tape are laminated with each other, and the laminated layer provides constraints on the laminated layer; during the winding process of the paper tape, the laminated layer generates a self-tightening force under the constraint of the laminated layer, thereby strengthening the entire paper tape layer; experiments show that compared with the paper tape layer with non-laminated layers, the paper tape layer with laminated layers has better anti-torsion performance after adhering to the bamboo tape layer to form a straw. Preferably, the thickness range of the lamination of adjacent layers of the paper tape is 1 mm - 3 mm.

[0041] In an embodiment of the present invention, the size of the overlapping thickness is positively correlated with the size of the spiral angle of the paper tape winding; specifically, in the production process, in order to avoid excessive overlapping of the joints of the paper tape winding with the joints of the bamboo tape layer, it is preferable to control the spiral angle of the paper tape layer within a relatively large range. However, during the spiral winding process, under the condition of a fixed paper tape width, the larger the spiral angle, the smaller the overlapping thickness of the paper tape. At this time, the grammage of the paper tape per unit area is relatively low, and the strengthening effect on the bamboo tape layer is relatively poor. To solve this problem, when the spiral angle of the paper tape winding tends to increase, in order to ensure the grammage of the paper tape per unit area, it is necessary to increase the overlapping thickness between the paper tape layers by increasing the width of the paper tape, that is, the size of the overlapping thickness of the paper tape is positively correlated with the size of the spiral angle of the paper tape winding.

[0042] In some embodiments of the present invention, tests show that in some cases, according to the technical requirements of the inner diameter or outer diameter of the straw, it is also necessary to adaptively adjust the size of the overlapping thickness and the size of the spiral angle. The preferred parameters at least include: the inner diameter of the straw is 5 mm - 12 mm, the outer diameter is 6 mm - 13 mm; the overlapping thickness is 1 mm - 3 mm, and the spiral angle is 35° - 55°.

[0043] In some embodiments of the present invention, the bamboo tape 3 and the paper tape 4 are wound in the same direction.

[0044] As can be seen from the above description, in order to make the joints generated by the winding of the bamboo tape 3 and the joints generated by the winding of the paper tape 4 cover each other and avoid excessive intersection of the joints, the bamboo tape 3 and the paper tape 4 of the straw in the embodiments of the present invention are wound in the same direction.

[0045] In some embodiments of the present invention, the bamboo tape 3 and the paper tape 4 are wound in opposite directions.

[0046] As can be seen from the above description, in order to improve the tensile and anti-torsion properties of the straw, the bamboo tape 3 and the paper tape 4 are wound in opposite directions. When encountering a torsional force, the bamboo tape layer 1 and the paper tape layer 2 with opposite winding directions provide binding forces to each other and are not easily deformed. Specifically, when the straw in the embodiments of the present invention encounters a torsional force, the winding direction of one of the paper tape layer and the bamboo tape layer with opposite winding directions must form an acute angle with the torsional force. At this time, the torsional force strengthens the winding effect of this layer and generates a self-tightening effect under the action of the torsional force, thereby absorbing the torsional force and further limiting the possibility of cracking of the other layer due to torsion.

[0047] In some embodiments of the present invention, the spiral angle of the bamboo tape 3 winding is smaller than the spiral angle of the paper tape 4 winding.

[0048] As can be seen from the above description, in order to reduce the seams of the paper tape 4, in this embodiment, the spiral angle of the bamboo tape layer 1 winding is smaller than that of the paper tape layer 2 winding. That is, when winding straws of the same height, since the spiral angle of the bamboo tape 3 winding is smaller than that of the paper tape 4 winding, the number of layers of the paper tape 3 winding is smaller than that of the bamboo tape 3 winding, thereby reducing the number of seams generated during the winding of the paper tape 4 and improving the waterproof performance of the straw. In some embodiments of the present invention, the paper tape layer 2 includes at least one paper tape 4 attached to at least a part of the inner surface of the bamboo tape layer 1. Specifically, the range of the spiral angle of the bamboo tape winding is between 30° and 45°, and the range of the spiral angle of the paper tape winding is between 46° and 70°; preferably, the range of the spiral angle of the bamboo tape winding is between 35° and 40° or between 40° and 45°, and the range of the spiral angle of the paper tape winding is between 50° and 60° or between 60° and 70°; more preferably, the spiral angle of the bamboo tape winding is 38°, 40°, 42° or 45°, and the spiral angle of the paper tape winding is 50°, 55°, 60° or 65°; it has been found that when the spiral angle of the paper tape winding is 55°, the optimal spiral angle of the bamboo tape winding is 40°; when the spiral angle of the bamboo tape winding is 45°, the optimal spiral angle of the paper tape winding is 65°. In some embodiments of the present invention, the paper tape layer 2 further includes at least one paper tape 4 attached to at least a part of the outer surface of the bamboo tape layer 1.

[0049] In some embodiments of the present invention, the paper tape layer 2 further includes at least one paper tape 4 attached to at least a part of the outer surface of the first tube body.

[0050] As can be seen from the above description, in the embodiments of the present invention, as Figure 1 , the paper tape layer 2 is located on the inner surface of the bamboo tape layer 1, that is, the bamboo tape layer 1 is on the outside, and the paper tape layer 2 is attached to the bamboo tape layer 1 on the inside, improving the tensile and torsional resistance of the bamboo tape layer 1 on the inner side of the bamboo tape layer 1; at the same time, the bamboo tape layer 1 located on the outside provides a protective effect for the paper tape layer 2 located on the inside, preventing the paper tape layer from being damaged by the outside.

[0051] Or, as Figure 2 , in the embodiments of the present invention, the paper tape layer 2 is located on the outer surface of the first tube body, that is, the bamboo tape layer 1 is on the inside, and the paper tape layer 2 is attached to the bamboo tape layer 1 on the outside, so as to improve the tensile and torsional resistance of the bamboo tape layer 1; at the same time, the paper tape layer 2 located on the outside also absorbs the burrs on the surface of the bamboo tape layer 1, improving the user experience;

[0052] Or, as Figure 3 , in the embodiments of the present invention, the paper tape layer 2 is attached to both the inner and outer sides of the first tube body, that is, the bamboo tape 3 is attached with the paper tape layer 2 on both the inside and outside, strengthening the bamboo tape layer 1 on both sides respectively, and at the same time absorbing the burrs on the surface of the bamboo tape layer 1.

[0053] In some embodiments of the present invention, the width of the bamboo strip 3 or the paper strip 4 located in the inner layer is smaller than the width of the bamboo strip 3 or the paper strip 4 located in the outer layer.

[0054] As can be seen from the above description, the width of the bamboo strip 3 or the paper strip 4 used for the bamboo strip layer 1 or the paper strip layer 2 increases from the inside to the outside, that is, the number of seams in the outer layer is less than the number of seams in the inner layer. During the production process, the seams generated when the bamboo strip 3 or the paper strip 4 in the outer layer is wound are more likely to avoid the seams in the inner layer, reducing the production difficulty; at the same time, the outer seams are reduced, improving the sealing performance of the straw. Specifically, research shows that during the winding process of each layer of the straw, the number of seam superpositions between each layer is negatively correlated with the torsional resistance of the straw, that is, the more the number of seam superpositions between each layer in the straw, the worse the torsional resistance of the straw. The inventor controls the width of the wound paper strip or bamboo strip to increase layer by layer from the inside to the outside, effectively reducing the number of seam superpositions in the straw, reducing the risk of straw failure, and improving the durability of the straw.

[0055] Specifically, the multiple range of the width of the paper strip or bamboo strip in the outer layer to the width of the paper strip or bamboo strip in the inner layer is 1.05 - 1.3 times; preferably 1.15 times. The width range of the bamboo strip in the inner layer is 20 mm - 29 mm; the width range of the paper strip in the inner layer is 15 mm - 30 mm.

[0056] In some embodiments of the present invention, an adhesive layer is provided between the bamboo strip layer 1 and the paper strip layer 2.

[0057] Specifically, the adhesive layer between the paper strip and the bamboo strip includes, but is not limited to, food-grade PVA (polyvinyl alcohol) glue, food-grade chitosan, food-grade starch glue, or food-grade latex and other adhesive materials to form an adhesive layer. The coating amount range of the adhesive layer is 10 g / m 2 - 30 g / m 2 .

[0058] In some embodiments of the present invention, adhesive layers are respectively provided on the opposite surfaces of the bamboo strip layer 1 and the paper strip layer 2.

[0059] As can be seen from the above description, an adhesive layer is provided between the bamboo strip layer 1 and the paper strip layer 2, that is, the bamboo strip layer 1 and the paper strip layer 2 are attached by gluing; specifically, in this embodiment, adhesive layers are respectively provided on the opposite surfaces of the bamboo strip layer 1 and the paper strip layer 2 to improve the attachment effect.

[0060] Specifically, in the embodiments of the present invention, when adhesive layers are provided on both surfaces of the paper strip layer and the bamboo strip layer, the coating amount range of the adhesive layer of the paper strip layer is 10 g / m 2 - 20 g / m 2 ; the coating amount range of the adhesive layer of the bamboo strip layer is 20 g / m 2 - 40 g / m 2 .

[0061] In some embodiments of the present invention, the adjacent layers of the wound bamboo strip 3 are joined together.

[0062] As can be seen from the above description, since the bamboo strip in the present invention is processed from raw bamboo and is not a composite material containing bamboo fibers, in order to improve the forming rate of the bamboo strip layer 1, the adjacent layers of the wound bamboo strip 3 are joined together, that is, the adjacent layers of the bamboo strip 3 do not overlap and are closely attached to avoid damage to the bamboo strip caused by overlapping; at the same time, the layers are joined to each other, and the surface of the formed bamboo strip layer 1 is smooth and has no convex structure, avoiding gaps left after the paper strip layer 2 is attached.

[0063] A method for preparing a straw, comprising:

[0064] A step of forming the bamboo strip layer 1, winding the bamboo strip 3 into the bamboo strip layer 1; the bamboo strip 3 is processed from raw bamboo by mechanical processing;

[0065] And, a step of forming the paper strip layer 2, winding the paper strip 4 to form the paper strip layer 2;

[0066] The paper strip is attached to at least part of the surface of the bamboo strip layer.

[0067] As can be seen from the above description, a method for preparing a straw is provided, which includes steps of forming the bamboo strip layer 1 and the paper strip layer 2, and strengthening the bamboo strip layer with the paper strip to improve the toughness of the bamboo strip layer during production and use and reduce the risk of cracking of the bamboo strip layer. Specifically, the winding methods include spiral winding, horizontal winding, cross winding, etc., and the specific winding method is selected according to production conditions and expected effects; the preferred winding method is spiral winding.

[0068] The bamboo strip at least includes a strip formed by mechanically processing from one end of a bamboo slice along the fiber direction of the bamboo to the other end. The thickness range of the bamboo strip in the embodiments of the present invention is 0.25 mm - 0.5 mm.

[0069] The paper strip at least includes a strip formed by cutting kraft paper, food-grade coated paper, reinforced paper, etc. The thickness range of the paper strip in the embodiments of the present invention is 30 - 220 g / cm 2 .

[0070] In some embodiments of the present invention, the step of forming the bamboo strip layer 1 is specifically: forming a single-layer bamboo tube by spirally winding the bamboo strip 3;

[0071] The step of forming the paper strip layer 2 is specifically: tightly winding the paper strip 4 on the outer surface of the single-layer bamboo tube to form a composite layer.

[0072] As can be seen from the above description, during the preparation process, the bamboo strip 3 is first wound into a single-layer bamboo tube as the base layer, providing good support for the subsequent winding of the paper strip 4 and preventing the collapse of the paper strip layer during winding. At the same time, the paper strip 4 has strong toughness, and the friction force is used to press and strengthen the bamboo strip layer during winding.

[0073] In some embodiments of the present invention, the step of forming the paper strip layer 2 is specifically: winding the paper strip 4 in a spiral manner to form a single-layer paper tube.

[0074] The step of forming the bamboo strip layer 1 is specifically: tightly winding the bamboo strip 3 on the outer surface of the single-layer paper tube to form a composite layer.

[0075] As can be seen from the above description, since the tension and toughness of the paper strip 4 are stronger than those of the bamboo strip 3 and are easier to control than the bamboo strip 3 during winding, in order to reduce the preparation difficulty, the paper strip 4 is wound as a single-layer paper tube first as the inner layer, providing a good attachment surface for the subsequent winding of the bamboo strip 3 and avoiding the situation of slipping or inaccurate positioning when the bamboo strip 3 is wound. Specifically, the bamboo strip cut from the raw bamboo in the present invention will be polished before processing to improve the surface smoothness of the bamboo strip. However, in the actual production process, the inventor found that due to the smooth surface of the bamboo strip, it is easy to slip or misalign with the winding shaft of the winding equipment during winding. Based on the discovery and traceability of this problem, the inventor winds the paper strip before the bamboo strip, uses the capillary structure on the paper strip to provide a certain roughness, and then prevents the inaccurate positioning when the bamboo strip is wound, improving the yield rate of the straw.

[0076] Even further, it further includes the step of:

[0077] Tightly winding the paper strip 4 on the outer surface of the composite layer.

[0078] As can be seen from the above description, on the basis of the paper strip layer 2 as the base layer and the bamboo strip layer 1 as the covering layer, the paper strip layer 2 is wound again on the outer surface of the bamboo strip layer 1 to press and strengthen the bamboo strip layer 1; at the same time, it absorbs the burrs on the surface of the bamboo strip layer 1 and improves the user experience.

[0079] In some embodiments of the present invention, the adjacent layers of the spiral winding of the paper strip 4 are overlapped.

[0080] As can be seen from the above description, in order to strengthen the overall strength of the straw, the paper strip layer 2 and the bamboo strip layer 1 are both formed by winding. Compared with the direct attachment of the paper, after the wound paper strip layer 2 is attached to the bamboo strip layer 1, from the perspective of force, the torsional resistance performance is better.

[0081] In some embodiments of the present invention, the adjacent layers of the spiral winding of the bamboo strip 3 are joined.

[0082] As can be seen from the above description, during the manufacturing process, in order to improve the forming rate of the bamboo strip layer 1, the adjacent layers wound by the bamboo strips 3 are joined, that is, the adjacent layers of the bamboo strips 3 do not overlap and are closely attached; at the same time, the layers are joined to each other, and the surface of the formed bamboo strip layer 1 is smooth and has no convex structure, avoiding gaps left after the paper strip layer 2 is attached.

[0083] In some embodiments of the present invention, it further includes a glue layer forming step:

[0084] Before winding, glue is applied to the opposite surface where the paper strip 4 and the bamboo strip 3 are attached;

[0085] Or glue is applied to the opposite surfaces where the paper strip 4 and the bamboo strip 3 are attached respectively.

[0086] As can be seen from the above description, in order to enhance the adhesion strength between the paper strip layer 2 and the bamboo strip layer 1, before winding, a glue layer is formed by applying glue on the single opposite surface where the paper strip 4 and the bamboo strip 3 are attached; or, before winding, glue is applied to both opposite surfaces where the paper strip 4 and the bamboo strip 3 are attached, that is, glue is applied to the paper strip 4 and the bamboo strip 3 as well, so as to form a stable glue layer. Specifically, during the winding process, both the paper strip and the bamboo strip need to absorb the momentum brought by the start or stop of the winding device, that is, acceleration is inevitably generated during the winding process. At this time, since the glue layer is in a liquid state, some flow phenomena will occur under the action of acceleration, resulting in uneven glue layer or a small amount of overflow. To solve this problem, the inventor chooses to apply glue separately on the opposite surface where the paper strip and the bamboo strip are attached. The principle is that the paper strip is relatively dense in texture and has a stronger adsorption force for the glue layer than the bamboo strip. During the winding process, the fluidity of the glue layer is relatively low, reducing the loss of the glue layer. In this gluing method, the amount of glue applied to the paper strip ranges from 20 g / m 2 -30 g / m 2 ; Another form in this example is: Glue is also applied to the opposite surface of the bamboo strip before winding. The purpose is to make the glue penetrate into the gaps between the layers wound by the bamboo strip layer, which can greatly improve the winding stability of the bamboo strip layer during the production process. The inventor found during the research and development process that when a certain bamboo strip is wound, when switching to another bamboo strip, due to the resilience of the bamboo fiber itself, the wound bamboo strip layer is prone to a retraction phenomenon that is difficult to detect with the naked eye, resulting in distortion of the shape of the straw itself during the subsequent winding of the paper strip. To solve this problem, glue is applied before winding the bamboo strip layer to improve the stability during the production process of the bamboo strip layer. In this gluing method, the amount of glue applied to the bamboo strip ranges from 20 g / m 2 -40 g / m 2 , and the amount of glue applied to the paper strip ranges from 10 g / m 2 -20 g / m 2 ; In some embodiments of the present invention, the spiral angle of the winding of the paper strip 4 is greater than the spiral angle of the winding of the bamboo strip 3.

[0087] In certain embodiments of the present invention, the range of the helix angle of the bamboo strip 3 winding is 30° - 45°, and the range of the helix angle of the paper strip 4 winding is 46° - 70°; specifically, the range of the helix angle of the bamboo strip winding is between 30° - 45°, and the range of the helix angle of the paper strip winding is between 46° - 70°; preferably, the range of the helix angle of the bamboo strip winding is between 35° - 40° or 40° - 45°, and the range of the helix angle of the paper strip winding is between 50° - 60° or 60° - 70°; more preferably, the helix angle of the bamboo strip winding is 38°, 40°, 42° or 45°, and the helix angle of the paper strip winding is 50°, 55°, 60° or 65°; it is found that when the helix angle of the paper strip winding is 55°, the best helix angle of the bamboo strip winding is 40°; when the helix angle of the bamboo strip winding is 45°, the best helix angle of the paper strip winding is 65°. From the above description, in order to reduce the seams of the paper strip 4, during the manufacturing process, the helix angle of the bamboo strip layer 1 winding is controlled to be less than the helix angle of the paper strip layer 2 winding. Compared with the larger paper strip layer 2, the number of seams of the bamboo strip layer 1 is less; at the same time, the helix angle of the paper strip 4 winding is different from the helix angle of the bamboo strip 3 winding, avoiding the coincidence of the seams of the bamboo strip layer 1 and the paper strip layer 2, which affects the waterproof performance and torsional resistance of the straw.

[0088] In certain embodiments of the present invention, before the formation of the bamboo strip layer 1, the following steps are further included:

[0089] Gluing the bamboo strip 3 with the composite paper.

[0090] From the above description, in order to enhance the transverse tensile strength of the bamboo strip 3 during the winding process, before winding, the composite paper is glued to the bamboo strip 3 and then wound. After the bamboo strip 3 is wound to form the bamboo strip layer 1, the surfaces of the composite paper and the paper strip layer 2 facing each other are respectively coated with glue and glued. Specifically, during the winding process of the bamboo strip, the winding device runs to wind the bamboo strip from a strip shape into a cylindrical shape. Inevitably, the device transfers momentum to the bamboo strip. Since the bamboo strip itself is brittle and hard, when suddenly bearing a large amount of momentum from a static state, it is easy to cause damage to the bamboo fibers. However, some damages cannot be directly reflected in the macroscopic production process, but only appear as cracking of the bamboo strip layer during subsequent storage and transportation and use processes. Based on the discovery and tracing of this problem, the inventor glues the bamboo strip with the composite paper before winding to enhance the toughness of the bamboo strip during winding, successfully absorbs the momentum transmitted when the mechanical device starts, thereby reducing the risks of cracking and breaking, reducing the failure risk of the straw, and improving the yield rate of the straw.

[0091] The present invention discloses a straw and its preparation method, which is mainly applied to the field of disposable straws, and provides a straw that can be naturally degraded and has strong durability. The following is a specific description in combination with embodiments.

[0092] Embodiment 1

[0093] Please refer toFigure 1 or Figure 2 , a straw, comprising:

[0094] a bamboo strip layer 1, the bamboo strip layer 1 is a first tube body formed by winding bamboo strips 3, and the bamboo strips 3 are formed by mechanically processing raw bamboo; as a structural support layer of the straw, it solves the problem that paper straws are prone to softening;;

[0095] a paper strip layer 2, the paper strip layer 2 includes a paper strip 4, and the paper strip 4 is attached to at least part of the surface of the bamboo strip layer 1, and the toughness of the paper strip 4 itself is used to strengthen the bamboo strip layer 1, solving the problems of poor tensile and torsional resistance of bamboo straws.

[0096] At the same time, compared with pure bamboo straws, in this embodiment, the usage amount of the bamboo strips 3 in the straw is reduced, and the paper strip 4 is attached to the bamboo strips 3, reducing the manufacturing difficulty, and the finished product rate reaches more than 99%, while saving production costs.

[0097] Specifically, the forming method of the bamboo strip layer 1 is spiral winding;

[0098] As Figure 1 shown, in this example, a structural form of the straw is: the paper strip layer 2 includes a paper strip 4 attached to at least part of the inner surface of the bamboo strip layer 1. That is, the bamboo strip layer 1 is on the outside, and the paper strip layer 2 is attached to the bamboo strip layer 1 on the inside to improve the tensile and torsional resistance of the bamboo strip layer 1;

[0099] As Figure 2 shown, in this example, another structural form of the straw is: the paper strip layer 2 includes a paper strip 4 attached to at least part of the outer surface of the bamboo strip layer 1. That is, the bamboo strip layer 1 is on the inside, and the paper strip layer 2 is attached to the bamboo strip layer 1 on the outside to improve the tensile and torsional resistance of the bamboo strip layer 1; at the same time, the paper strip layer 2 located on the outside also takes into account absorbing the burrs on the surface of the bamboo strip layer 1 and improving the user experience.

[0100] Embodiment 2

[0101] As Figure 3 and Figure 4 shown, the difference between this embodiment and Embodiment 1 is that:

[0102] On the basis that the paper strip layer includes a paper strip 4 attached to at least part of the inner surface of the bamboo strip layer 1, the paper strip layer 2 further includes at least one paper strip 4 attached to at least part of the outer surface of the bamboo strip layer 1. That is, the paper strip layer 2 is attached to both the inside and outside of the bamboo strip 3, strengthening the bamboo strip layer 1 on both sides, and at the same time absorbing the burrs on the surface of the bamboo strip layer 1.

[0103] Embodiment 3

[0104] On the basis of Embodiment 1, the adjacent layers wound by the bamboo strip 3 are joined. That is, in order to improve the forming rate of the bamboo strip layer 1, the adjacent layers wound by the bamboo strip 3 are joined, that is, the adjacent layers of the bamboo strip 3 do not overlap and are closely attached; at the same time, the layers are joined to each other, and the surface of the formed bamboo strip layer 1 is smooth and has no convex structure, avoiding gaps left after the paper strip layer 2 is attached.

[0105] Embodiment 4

[0106] On the basis of Embodiment 1, the paper strip layer 2 is a tube formed by winding the paper strip 4. That is, in order to strengthen the overall strength of the straw, the paper strip layer 2 and the bamboo strip layer 1 are both formed by winding. Compared with directly attaching the paper, after the wound paper strip layer 2 is attached to the bamboo strip layer 1, from the perspective of force, the anti-torsion performance is better.

[0107] Specifically, in this embodiment, the adjacent layers wound by the paper strip 4 overlap, and the forming method of the paper strip layer 2 is spiral winding; the purpose is: in order to reduce the manufacturing difficulty and considering the relatively soft texture of the paper strip 4, the paper strip layer 2 is formed by overlapping the adjacent layers of the paper strip 4. At the same time, the paper strip layer 2 with adjacent layers overlapping layer by layer has better waterproof performance than the joint structure; preferably, the overlapping range between the layers of the paper strip 4 is 1-3 mm, preferably 1 mm, 1.5 mm or 2 mm; the overlapping value is positively correlated with the spiral angle of the paper strip 4.

[0108] In addition, the winding directions of the bamboo strip 3 and the paper strip 4 are the same; that is, in order to make the seams generated by the winding of the bamboo strip 3 and the seams generated by the winding of the paper strip 4 cover each other, avoiding excessive intersection of the seams, so the winding directions of the conventional bamboo strip 3 and the paper strip 4 in the embodiments of the present invention are the same.

[0109] Alternatively, the winding directions of the bamboo strip 3 and the paper strip 4 are opposite; that is, in order to improve the tensile and anti-torsion performance of the straw, the winding directions of the bamboo strip 3 and the paper strip 4 are opposite. When encountering a torsional force, the bamboo strip layer 1 and the paper strip layer 2 with opposite winding directions provide binding forces to each other and are not easily deformed.

[0110] Embodiment 5

[0111] On the basis of Embodiment 1, the spiral angle of the bamboo strip 3 winding is smaller than the spiral angle of the paper strip 4 winding.

[0112] That is, in this embodiment, in order to reduce the seams of the paper strip 4, the spiral angle of the bamboo strip layer 1 winding in this embodiment is smaller than the spiral angle of the paper strip layer 2 winding; at the same time, the spiral angle of the paper strip 4 winding is different from the spiral angle of the bamboo strip 3 winding, avoiding the coincidence of the seams of the bamboo strip layer 1 and the paper strip layer 2, which affects the waterproof performance and anti-torsion performance of the straw.

[0113] Specifically, the spiral angle of the bamboo strip 3 winding is 45°, and the spiral angle of the paper strip 4 winding is 50°.

[0114] Example Six

[0115] On the basis of Example One, the width of the bamboo strip 3 or paper strip 4 located in the inner layer is less than the width of the bamboo strip 3 or paper strip 4 located in the outer layer. That is, from the inside to the outside, the width of the bamboo strip 3 or paper strip 4 used in the bamboo strip layer 1 or paper strip layer 2 increases, which facilitates the bamboo strip 3 or paper strip 4 to more easily cover the seams in the inner layer, while reducing the outer seams and improving the sealing performance of the straw.

[0116] Specifically, the width of the paper strip or bamboo strip located in the outer layer is 1.15 times the width of the paper strip or bamboo strip located in the inner layer.

[0117] Example Seven

[0118] On the basis of Example One, an adhesive layer is provided between the bamboo strip layer 1 and the paper strip layer 2. That is, an adhesive layer is provided between the bamboo strip layer 1 and the paper strip layer 2, that is, the bamboo strip layer 1 and the paper strip layer 2 are attached by gluing; specifically, adhesive layers are respectively provided on the opposite surfaces of the bamboo strip layer 1 and the paper strip layer 2 to improve the attachment effect. As Figure 4 shown, the adhesive layer is between the bamboo strip layer 1 and the paper strip layer 2.

[0119] Example Eight

[0120] A method for manufacturing a straw, comprising:

[0121] A step of forming the bamboo strip layer 1, winding the bamboo strip 3 spirally to form the bamboo strip layer 1; the bamboo strip 3 is formed by mechanical processing of raw bamboo; a step of forming the paper strip layer 2, winding the paper strip 4 spirally to form the paper strip layer 2; the paper strip is attached to at least a part of the surface of the bamboo strip layer.

[0122] Among them, the bamboo strip includes: a strip-shaped object cut from one end of the bamboo piece along the fiber direction of the bamboo, and the thickness range of the bamboo strip in the embodiment of the present invention is 0.25 mm - 0.5 mm.

[0123] The paper strip at least includes strip-shaped objects cut from kraft paper, food-grade coated paper, reinforced paper, etc. The thickness range of the paper strip in this embodiment is 60 g / cm 2 .

[0124] Example Nine

[0125] On the basis of Example Eight, the step of forming the bamboo strip layer 1 is specifically: forming a single-layer bamboo tube by winding the bamboo strip 3 in a spiral manner, and then tightly winding the paper strip 4 on the outer surface of the single-layer bamboo tube to form a composite layer; that is, in the manufacturing process, the bamboo strip 3 is wound as the inner layer first as the base layer, providing good support for the subsequent winding of the paper strip 4, and avoiding the collapse of the paper strip layer during the winding process; at the same time, since the paper strip 4 has strong toughness, the friction force is used to press and strengthen the bamboo strip layer during winding.

[0126] Example Ten

[0127] On the basis of the eighth embodiment, the specific steps for forming the paper tape layer 2 are as follows: The paper tape 4 is formed into a single-layer paper tube in a spiral winding manner; subsequently, the bamboo tape 3 is tightly wound around the outer surface of the single-layer paper tube to form a composite layer. The principle lies in that: since the tension and toughness of the paper tape 4 are stronger than those of the bamboo tape, it is easier to control than the bamboo tape 3 during the winding process. In order to reduce the preparation difficulty, the paper tape 4 is wound as an inner layer into a single-layer paper tube first, providing a good attachment surface for the subsequent winding of the bamboo tape 3, and avoiding the situation of slipping or inaccurate positioning during the winding of the bamboo tape.

[0128] Preferably, after forming the composite layer, the paper tape 4 is tightly wound around the outer surface of the composite layer. Since the bamboo tape layer 1 in the composite layer is located on the outside at this time and lacks restraint and reinforcement, the paper tape layer 2 is wound outside the outer surface of the bamboo tape layer 1, providing a pressing force to the bamboo tape layer 1. At the same time, the paper tape layer 2 absorbs the burrs on the surface of the bamboo tape layer 1, improving the user experience.

[0129] Embodiment Eleven

[0130] On the basis of the ninth or tenth embodiment, the adjacent layers of the spiral winding of the paper tape 4 are overlapped. That is, during the manufacturing process, in order to strengthen the overall strength of the straw, the paper tape layer 2 and the bamboo tape layer 1 are both formed by winding. Compared with directly attaching the paper, after the wound paper tape layer 2 is attached to the bamboo tape layer 1, from the perspective of force, the anti-torsion performance is better.

[0131] The adjacent layers of the spiral winding of the bamboo tape 3 are joined. That is, in order to improve the forming rate of the bamboo tape layer 1, the adjacent layers of the winding of the bamboo tape 3 are joined, that is, the adjacent layers of the bamboo tape 3 do not overlap and are closely attached; at the same time, the layers are joined to each other, and the surface of the formed bamboo tape layer 1 is smooth and has no convex structure, avoiding gaps after the paper tape layer 2 is attached.

[0132] Embodiment Twelve

[0133] On the basis of the ninth or tenth embodiment, before forming the bamboo tape layer 1, the steps also include: gluing the bamboo tape 3 with the composite paper. That is, in order to enhance the transverse tensile strength of the bamboo tape 3 during the winding process, before winding, the composite paper and the bamboo tape 3 are glued and then wound. After the bamboo tape 3 is wound to form the bamboo tape layer 1, the surfaces of the composite paper and the paper tape layer 2 facing each other are respectively coated with glue for gluing and attachment.

[0134] An application example of the preparation method of a straw in the present invention is as follows:

[0135] The specific steps for manufacturing a straw with the paper tape layer 2 located outside the bamboo tape layer 1 are as follows:

[0136] First, polish both sides of the bamboo tape 3 before manufacturing;

[0137] Then, before winding, apply glue to the adhesive surfaces of the bamboo strip 3 and the paper strip 4 respectively (or only apply glue to the adhesive surface of the paper strip 4 and the bamboo strip 3 to save manufacturing costs). Even if the glue-coated surfaces of the paper strip 4 and the bamboo strip 3 face each other, take the width of the paper strip 4 to be 1.05 - 1.3 times (preferably 1.15 times) the width of the bamboo strip 3. Through the guiding mechanism, the bamboo strip 3 approaches the winding mandrel for winding to form the inner bamboo strip layer 1, and the paper strip 4 is attached to the bamboo strip layer 1 for winding to form the outer paper strip layer 2. During the winding process, control the guiding mechanism to wind at different helix angles respectively, where the helix angle of the paper strip 4 winding is greater than that of the bamboo strip 3 winding. Specifically, the helix angle of the bamboo strip 3 winding is fixed at 45°, and the edges of the bamboo strip 3 are closely attached to each other without overlapping during winding. The helix angle of the paper strip 4 winding is taken as 55°, and the paper strips 4 overlap each other during winding (the overlapping width is positively correlated with the helix angle of the paper strip 4 winding), and the paper strip 4 gradually wraps the bamboo strip layer 1 to form a composite cylinder;

[0138] Finally, cut the made cylinder into straws according to a preset length.

[0139] In addition, in order to prevent the bamboo strip 3 from breaking during winding, before winding the bamboo strip 3, first glue the bamboo strip 3 to the composite paper to enhance the transverse tensile strength of the bamboo strip 3. After the bamboo strip 3 is wound, the composite paper layer is on the outer surface of the bamboo strip 3, and then the paper strip 4 is wound on the outer surface of the composite paper layer and glued into a cylinder.

[0140] In summary, the present invention provides a straw and its preparation method. By cutting the raw bamboo into bamboo strips and winding the bamboo strips to form a bamboo strip layer as the structural support layer of the straw, the problem of easy softening of paper straws is solved. At the same time, a paper strip layer is attached to the bamboo strip layer, and the toughness of the paper strip itself is used to strengthen the bamboo strip layer, solving the problems of poor tensile and torsional resistance of bamboo straws. In addition, compared with pure bamboo straws, the bamboo paper straws disclosed in the present invention reduce the usage amount of bamboo strips in the straws, adopt the attachment of paper strips and bamboo strips, reduce the manufacturing difficulty, and the finished product rate reaches more than 99%, while saving production costs.

[0141] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent transformations made using the content of the specification and drawings of the present invention, or directly or indirectly applied in related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A straw, characterized in that: comprising: at least one bamboo strip layer, the bamboo strip layer being a first tube body formed by winding bamboo strips; the bamboo strips being formed by mechanically processing raw bamboo; at least one paper strip layer, the paper strip layer including paper strips, the paper strips being attached to at least part of the surface of the first tube body.

2. The straw according to claim 1, characterized in that: the paper strip layer is a second tube body formed by winding paper strips.

3. The straw according to claim 2, characterized in that: the adjacent layers wound by the paper strips are overlapped.

4. The straw according to claim 2, characterized in that: the bamboo strips and the paper strips are wound in the same direction.

5. The straw according to claim 2, characterized in that: the bamboo strips and the paper strips are wound in opposite directions.

6. The straw according to claim 2, characterized in that: the helix angle of the wound bamboo strips is smaller than the helix angle of the wound paper strips.

7. The straw according to claim 6, characterized in that: the range of the helix angle of the wound bamboo strips is 30° - 45°.

8. The straw according to claim 6, characterized in that: the range of the helix angle of the wound paper strips is 46° - 70°.

9. The straw according to claim 2, characterized in that: the paper strip layer includes at least one paper strip attached to at least part of the inner surface of the first tube body.

10. The straw according to claim 9, characterized in that: the paper strip layer further includes at least one paper strip attached to at least part of the outer surface of the first tube body.

11. The straw according to claim 2, characterized in that: the paper strip layer further includes at least one paper strip attached to at least part of the outer surface of the first tube body.

12. The straw according to any one of claims 9 - 11, characterized in that: the width of the bamboo strips or the paper strips located in the inner layer is smaller than the width of the bamboo strips or the paper strips located in the outer layer.

13. The straw according to claim 12, characterized in that: the width range of the bamboo strips located in the innermost layer is 15mm - 30mm.

14. The straw according to claim 12, characterized in that: the width range of the paper strips located in the innermost layer is 20mm - 29mm.

15. The straw according to claim 1, characterized in that: a glue layer is provided between the bamboo strip layer and the paper strip layer.

16. The straw according to claim 15, characterized in that: glue layers are respectively provided on the opposite surfaces of the bamboo strip layer and the paper strip layer.

17. The straw according to claim 1, characterized in that: the adjacent layers wound by the bamboo strips are joined.

18. A method for preparing a straw, characterized in that: comprising: a bamboo strip layer forming step of winding bamboo strips into a bamboo strip layer; the bamboo strips being formed by mechanically processing raw bamboo; and, a paper strip layer forming step of winding paper strips to form a paper strip layer; the paper strips being attached to at least part of the surface of the bamboo strip layer.

19. The method for preparing a straw according to claim 18, characterized in that: The specific steps for forming the bamboo strip layer are as follows: forming a single-layer bamboo tube by spirally winding the bamboo strips; The specific steps for forming the paper strip layer are as follows: tightly winding the paper strip around the outer surface of the single-layer bamboo tube to form a composite layer.

20. A method for preparing a straw according to claim 18, wherein: The specific steps for forming the paper strip layer are as follows: forming a single-layer paper tube by spirally winding the paper strip; The specific steps for forming the bamboo strip layer are as follows: tightly winding the bamboo strip around the outer surface of the single-layer paper tube to form a composite layer.

21. A method for preparing a straw according to claim 20, wherein: It further includes the step of: Tightly winding the paper strip around the outer surface of the composite layer.

22. A method for preparing a straw according to any one of claims 19-21, wherein: The helix angle of the paper strip winding is greater than the helix angle of the bamboo strip winding.

23. A method for preparing a straw according to claim 22, wherein: The helix angle of the bamboo strip winding is 30°-45°.

24. A method for preparing a straw according to claim 22, wherein: The range of the helix angle of the paper strip winding is 46°-70°.

25. A method for preparing a straw according to any one of claims 19-21, wherein: The adjacent layers of the spiral winding of the paper strip are overlapped.

26. A method for preparing a straw according to any one of claims 19-21, wherein: The adjacent layers of the spiral winding of the bamboo strip are joined.

27. A method for preparing a straw according to any one of claims 19-21, wherein: It further includes the step of forming an adhesive layer: Before winding, apply glue on the opposite surfaces where the paper strip and the bamboo strip are attached; Or apply glue on the opposite surfaces where the paper strip and the bamboo strip are attached respectively.

28. A method for preparing a straw according to any one of claims 19-21, wherein: Before forming the bamboo strip layer, it further includes the step of: Gluing the bamboo strip and the composite paper.

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