Production method of composite bamboo cup

Abstract

The invention discloses a production method of a composite bamboo cup. The production method comprises the following steps: [1] compounding multiple layers of bamboo strip micro-thin sheets; (2) preparing a lining layer; [3] producing a core mold; (4) winding the paper tape into a lining layer; (5) winding the bamboo belt layer into a cup body; [6] curling the rim of the cup; and (7) sealing the cup bottom. The prepared composite bamboo cup replaces a traditional paper cup and is more environmentally friendly and healthy, the cup body is good in physical performance and natural in appearance performance, further processing is not needed, and pollution is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of bamboo material processing, in particular to a production method of a composite bamboo cup. Background Art

[0002] Traditional paper cups are typically disposable and widely used in homes, offices, public spaces, and the restaurant industry. They are particularly popular for hot beverages like coffee and milk tea. Their portability and the fact that they require no cleaning make them a common choice in our fast-paced lives. Currently, there are three main types of paper cups on the market: wax-coated cups, straight-walled double-layer cups, and polyethylene-coated cups. Paper cups are typically manufactured from paper pulp through processes such as die-cutting, printing, and coating.

[0003] However, there are many problems with the existing paper cup technology. When wax-coated cups are used to hold hot drinks above 40°C, the wax layer may melt and release harmful substances. Some low-quality paper cups use recycled pulp or excessive whitening agents, which leads to chemical residues and affects the health of users. Ordinary paper cups rely on double air layers or thin coatings, resulting in limited anti-scalding effects. In addition, the paper cup material is relatively fragile and easily broken or leaked under pressure. Traditional paper cups are also prone to slipping when grasped due to their smooth outer walls. Most paper cups cannot be mixed with ordinary paper for recycling due to the PE coating, and the degradation cycle is long, resulting in waste of resources and white pollution. At the same time, the manufacture of paper cups requires a large amount of wood and energy. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a production method of a composite bamboo cup. The composite bamboo cup replaces the traditional paper cup, which is more environmentally friendly and healthy, has good physical properties of the cup body, natural appearance, and does not require further processing to avoid pollution.

[0005] The present invention adopts the following technical solution: a method for producing a composite bamboo cup, which comprises the following steps:

[0006] [1] Multi-layer composite of bamboo strip micro-sheets: After laminating the multi-layer bamboo strip micro-sheets, they are subjected to one or more operations of fusion, stacking, winding, and composite under heating conditions, and the bamboo strip micro-sheets are processed into the required fan-shaped bamboo belt size according to the size requirements of bamboo cup production;

[0007] [2] Preparation of lining layer: Calculate the food-grade coated paper according to the unfolded area of ​​the cup body, and use cutting equipment to cut it into precise fan-shaped paper, leaving a certain area at both ends of the fan;

[0008] [3] Production of core mold: According to the required inner diameter of the bamboo cup, a core mold of corresponding specifications is processed. Thermoplastic high-temperature resistant resin is poured into the mold. After cooling to room temperature and the resin is formed, the core mold is removed from the mold, polished, and positioning grooves are opened;

[0009] [4] Paper tape is wound into an inner lining layer: food-grade starch glue is applied to the inner wall of the fan-shaped paper sheet in advance, and food-grade silicone oil is sprayed on the surface of the core mold in advance. After preheating, the fan-shaped paper sheet is continuously wound around the core mold at a certain spiral angle. Glue is additionally applied to the joints of the paper tape at the beginning and end, and pressurized by a hot pressing wheel to strengthen the joints to obtain the inner lining paper layer;

[0010] [5] Rolling the bamboo strips into a cup body: Heat and soften the pre-cut fan-shaped bamboo strips, spirally wrap them along the core mold axis and cover the surface of the inner lining paper layer. Apply food-grade polyisocyanate emulsion adhesive evenly on the joints and adhere them. Apply sufficient pressure to make the fan-shaped bamboo strips and the inner lining paper layer fit together. Then put them into an oven and heat them to completely cure the adhesive layer. De-molding the composite bamboo cup is completed.

[0011] [6] Cup rim curling: Fix the composite bamboo cup upside down on a rotating workbench, with the cup rim exposed to a certain size. Use a steam nozzle to soften the exposed part of the cup rim with a circular spray. Apply food-grade starch glue to the softened area to form a bonding transition layer. Use a curling machine to fold the bamboo material of the cup rim inward to form the cup rim curling;

[0012] [7] Sealing the cup bottom: Place the composite bamboo cup upside down on a rotating fixture with the bottom of the cup facing outward. Cut the composite bamboo board into a circular bottom film with chamfered edges. Use a double-sided coating process to spray food-grade polyisocyanate emulsion adhesive on the end of the cup body. Use food-grade starch glue to dot-map glue on the joint surface of the bottom film. Then press the bottom film to the cup body. Heat and pressurize it and wait for the glue layer to solidify before taking out the composite bamboo cup.

[0013] As an improvement, in step [1] of multi-layer composite of bamboo strip micro-sheets, the multi-layer bamboo strip micro-sheet coating is an alternating stack of bamboo strip micro-sheets and food-grade paperboard, wherein the bamboo strip micro-sheets are subjected to high-temperature hot pressing to arrange the fibers in a directional manner, and the inner wall of the food-grade paperboard is coated with a waterproof coating.

[0014] As an improvement, in step [5], the bamboo tape layer is wound into the cup body, and the fan-shaped bamboo tape and the inner lining paper layer are wound in opposite directions with a certain spiral angle difference, and the angle difference is controlled so that the fan-shaped bamboo tape completely covers the seam of the inner lining paper layer.

[0015] As an improvement, the fan-shaped bamboo belt and the inner lining paper layer are wound in opposite directions with a spiral angle difference of 10-15°, wherein the spiral angle of the inner lining paper layer is 20-25° and the spiral angle of the fan-shaped bamboo belt is 35-40°.

[0016] As an improvement, in step [1] of multi-layer composite of bamboo strip micro-sheets, 3-5 layers of bamboo strip micro-sheets are stacked alternately with food-grade polyisocyanate emulsion adhesive, and hot-pressed at 120°C to form the desired fan-shaped bamboo strips, with a coating amount of 15-25g / m 2 , the thickness is controlled at 1-2mm.

[0017] As an improvement, in step [2], during the preparation of the inner lining layer, a 5 mm overlapping area is reserved at both ends of the fan.

[0018] As an improvement, in step [4], the paper tape is wound into the inner lining layer, the preheating temperature is 50-60°C, the fan-shaped paper skin is continuously wrapped around the core mold at a spiral angle of 15-25°, the overlapping width of adjacent paper tapes is 3mm, and the additional glue coating amount at the head and tail seams of the paper tape is 20g / m 2 , heat the hot pressing wheel to 60℃ for 10-15s.

[0019] As an improvement, in step [5], the bamboo tape layer is wound into the cup body, the fan-shaped bamboo tape is heated and softened to a temperature of 80-100°C; the pressure applied when the fan-shaped bamboo tape and the inner lining paper layer are bonded to each other is 0.5-1.0 MPa; the oven temperature is 60-80°C, and the heating is performed for 20-30 minutes.

[0020] As an improvement, in step [6], when curling the cup mouth, the cup mouth is exposed 5-8 mm, and a steam nozzle is used to spray the exposed part of the cup mouth in a circular manner at 105°C and 0.1 MPa for 15-20 seconds to soften it. The softened area is coated with food-grade starch glue with a solid content of 20%, a viscosity of 800 mPa·s, and a coating amount of 10 g / m 2 , forming a bonding transition layer.

[0021] As an improvement, in step [7] of cup bottom sealing, the coating amount of food-grade polyisocyanate emulsion adhesive is 20g / m 2 , preheat to 50℃ to accelerate penetration.

[0022] As an improvement, in step [7], during the cup bottom sealing, the remaining bamboo strips from the cutting in step [1] are collected as composite bamboo boards and cut into circular bottom sheets.

[0023] Beneficial effects of the present invention:

[0024] 1. Environmental sustainability and green health: Bamboo is a fast-growing plant with a low environmental impact. Using bamboo strips to create composite bamboo cups is more environmentally friendly than traditional disposable plastic cups and effectively reduces plastic pollution. Composite bamboo cups use bamboo as the core raw material, combined with food-grade cardboard and a fully bio-based adhesive to create a fully biodegradable "bamboo-paper" composite structure. Bamboo grows in just 3-5 years and requires no fertilizers or pesticides, resulting in an 85% reduction in carbon emissions compared to plastic cups.

[0025] 2. High performance and functional integration: Through the collaborative design of the directional arrangement of bamboo fibers, the cup body has high strength, high thermal insulation and antibacterial properties, improved mechanical properties, and can withstand multiple drops without damage; the thermal insulation performance is improved compared to traditional double-layer paper cups, and the upper temperature resistance limit is increased.

[0026] 3. Natural aesthetics and humanized design: Bamboo has natural texture and color. The interlaced texture of bamboo fibers and the coating form a unique decorative effect. Compared with traditional printed paper cups, it reduces the use of ink by 80%, avoiding the risk of chemical pollution. The surface roughness is lower than that of traditional paper cups, but the friction is improved and the anti-slip performance is excellent. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are described in detail below.

[0028] Example 1

[0029] A method for producing a composite bamboo cup comprises the following steps:

[0030] [1] Multi-layer composite of bamboo strip micro-sheets: After laminating the multi-layer bamboo strip micro-sheets, they are subjected to one or more operations of fusion, stacking, winding, and composite under heating conditions, and the bamboo strip micro-sheets are processed into the required fan-shaped bamboo belt size according to the size requirements of bamboo cup production;

[0031] [2] Preparation of lining layer: Calculate the food-grade coated paper according to the unfolded area of ​​the cup body (sector arc length = cup mouth circumference, radius = cup body oblique height), and use cutting equipment to cut into precise sector-shaped paper, leaving a 5mm overlap area at both ends of the sector to avoid seam misalignment;

[0032] [3] Production of core mold: According to the required inner diameter of the bamboo cup, a core mold of corresponding specifications is processed. Thermoplastic high-temperature resistant resin is poured into the mold. After cooling to room temperature and the resin is formed, the core mold is removed from the mold, polished, and positioning grooves are opened;

[0033] [4] Paper tape is wound into the inner lining layer: food-grade starch glue is applied to the inner wall of the fan-shaped paper sheet in advance, and food-grade silicone oil (release agent) is sprayed on the surface of the core mold in advance. After preheating at a temperature of 50-60°C, the fan-shaped paper sheet is continuously wound around the core mold at a spiral angle of 15-25°. The overlapping width of adjacent paper tapes is 3mm to ensure sealing. Glue is additionally applied to the joints of the paper tape at a coating amount of 20g / m 2 , pressurize and heat at 60℃ for 10-15s through hot pressing wheels to strengthen the seams and obtain the inner lining paper layer;

[0034] [5] Rolling the bamboo strips into a cup body: Heat the pre-cut fan-shaped bamboo strips at 80-100℃ to soften them, and spirally wrap them along the core mold to cover the surface of the inner lining paper layer. Evenly apply food-grade polyisocyanate emulsion adhesive to the joints, and apply 0.5-1.0MPa pressure to fully adhere the fan-shaped bamboo strips and the inner lining paper layer. Then put them into an oven at 60-80℃ for 20-30 minutes to completely cure the adhesive layer, and demould to obtain a composite bamboo cup.

[0035] [6] Cup rim curling: Fix the composite bamboo cup upside down on a rotating workbench, with the cup rim exposed 5-8mm. Use a steam nozzle to spray the exposed part of the cup rim in a circular manner at 105℃ and 0.1MPa for 15-20s to soften it, thereby increasing the moisture content of the bamboo fiber in the bamboo belt and cup body of the composite bamboo cup. Apply food-grade starch glue with a solid content of 20%, a viscosity of 800mPa·s, and a coating amount of 10g / m2 on the softened area. 2 , forming a bonding transition layer, and using a curling machine to fold the cup mouth bamboo material inward 180 degrees to form the cup mouth curling;

[0036] [7] Cup bottom sealing: Place the composite bamboo cup upside down on a rotating fixture with the bottom of the cup facing upwards. Collect the remaining bamboo strips from the cutting in step [1] as composite bamboo boards. Cut the composite bamboo boards into circular bottom sheets with chamfered edges. Use a double-sided coating process to spray food-grade polyisocyanate emulsion adhesive on the end surface of the cup body with a coating amount of 20g / m 2 , preheat to 50℃ to accelerate penetration, use food-grade starch glue to dot-matrix glue on the joint surface of the bottom film, then press the bottom film to the cup body, heat and press for 10s and take out the composite bamboo cup after the glue layer is cured.

[0037] In actual applications, the PE / wax coating of traditional paper cups contains chemical substances, which poses a risk of release. The present invention uses thin bamboo skin as the main material, which is natural and non-toxic. The food-grade paper skin composite inside and outside does not need to rely on PE / wax coating for waterproofing. In addition, the natural texture of bamboo can replace the printed decoration on the outer wall of the cup, which is natural and beautiful.

[0038] Traditional paper cups are prone to deformation and leakage; the bamboo skin fibers of the composite bamboo cup of the present invention are arranged in a crisscross pattern to form a natural grid structure, which significantly improves the compressive strength of the cup body; and after the bamboo skin and paper skin are compounded, the inner and outer layers work together to reduce the risk of the cup softening when holding hot drinks. The low thermal conductivity of bamboo itself also allows the bamboo cup to form an efficient heat insulation layer, reducing the problem of scalding; the natural concave and convex texture on the bamboo skin surface provides friction, and there is no need to add an additional anti-slip structure.

[0039] Traditional paper cups require a PE coating for waterproofing, which makes recycling difficult and causes long-term pollution. In addition, paper cups rely on wood, exacerbating forest resource depletion. The bamboo skin and food-grade paper skin in this invention are both naturally degradable materials, requiring no chemical coating, significantly shortening the overall degradation cycle. Moreover, because bamboo has a short growth cycle and does not need to be cut down, the bamboo flattening technology greatly improves the utilization rate of raw materials.

[0040] As an improved specific implementation method, in step [1] of multi-layer composite of bamboo strip micro-sheets, 3-5 layers of bamboo strip micro-sheets are stacked alternately with food-grade polyisocyanate emulsion adhesive, and hot-pressed at 120°C to form the desired fan-shaped bamboo strips, with a coating amount of 15-25g / m 2 , the thickness is controlled at 1-2mm.

[0041] The fan-shaped bamboo strips prepared by this design have good physical properties, ensuring mechanical strength and durability.

[0042] As an improved specific implementation method, in step [1], the multi-layer composite of bamboo strip micro-sheets, the multi-layer bamboo strip micro-sheet coating is an alternating stack of bamboo strip micro-sheets and food-grade paperboard, wherein the bamboo strip micro-sheets are subjected to high-temperature hot pressing to directional arrange fibers, and the inner wall of the food-grade paperboard is coated with a waterproof coating.

[0043] This design increases the compressive strength of the cup body by 2-3 times compared to traditional paper cups, achieving synergistic optimization of high strength and high waterproofness.

[0044] As an improved embodiment, in step [5], the bamboo tape layer is wound into the cup body, and the fan-shaped bamboo tape and the inner lining paper layer are wound in opposite directions with a certain spiral angle difference. The angle difference is controlled so that the fan-shaped bamboo tape completely covers the seam of the inner lining paper layer. The fan-shaped bamboo tape and the inner lining paper layer are wound in opposite directions with a spiral angle difference of 10-15°, wherein the spiral angle of the inner lining paper layer is 20-25° and the spiral angle of the fan-shaped bamboo tape is 35-40°.

[0045] By controlling the angle difference, the bamboo tape completely covers the paper tape seams, and combined with food-grade polyisocyanate emulsion adhesive for penetration and filling, the air tightness of the cup body is enhanced, achieving pressure maintenance without leakage, and completely eliminating the risk of leakage.

Claims

1. A method for producing a composite bamboo cup, characterized in that: It includes the following steps: [1] Multi-layer composite of bamboo strip micro-sheets: After laminating the multi-layer bamboo strip micro-sheets, they are subjected to one or more operations of fusion, stacking, winding, and composite under heating conditions, and the bamboo strip micro-sheets are processed into the required fan-shaped bamboo belt size according to the size requirements of bamboo cup production; [2] Preparation of lining layer: Calculate the food-grade coated paper according to the unfolded area of ​​the cup body, and use cutting equipment to cut it into precise fan-shaped paper, leaving a certain area at both ends of the fan; [3] Production of core mold: According to the required inner diameter of the bamboo cup, a core mold of corresponding specifications is processed. Thermoplastic high-temperature resistant resin is poured into the mold. After cooling to room temperature and the resin is formed, the core mold is removed from the mold, polished, and positioning grooves are opened; [4] Paper tape is wound into an inner lining layer: food-grade starch glue is applied to the inner wall of the fan-shaped paper sheet in advance, and food-grade silicone oil is sprayed on the surface of the core mold in advance. After preheating, the fan-shaped paper sheet is continuously wound around the core mold at a certain spiral angle. Glue is additionally applied to the joints of the paper tape at the beginning and end, and pressurized by a hot pressing wheel to strengthen the joints to obtain the inner lining paper layer; [5] Rolling the bamboo strips into a cup body: Heat and soften the pre-cut fan-shaped bamboo strips, spirally wrap them along the core mold axis and cover the surface of the inner lining paper layer. Apply food-grade polyisocyanate emulsion adhesive evenly on the joints and adhere them. Apply sufficient pressure to make the fan-shaped bamboo strips and the inner lining paper layer fit together. Then put them into an oven and heat them to completely cure the adhesive layer. De-molding the composite bamboo cup is completed. [6] Cup rim curling: Fix the composite bamboo cup upside down on a rotating workbench, with the cup rim exposed to a certain size. Use a steam nozzle to soften the exposed part of the cup rim with a circular spray. Apply food-grade starch glue to the softened area to form a bonding transition layer. Use a curling machine to fold the bamboo material of the cup rim inward to form the cup rim curling; [7] Sealing the cup bottom: Place the composite bamboo cup upside down on a rotating fixture with the bottom of the cup facing outward. Cut the composite bamboo board into a circular bottom film with chamfered edges. Use a double-sided coating process to spray food-grade polyisocyanate emulsion adhesive on the end of the cup body. Use food-grade starch glue to dot-map glue on the joint surface of the bottom film. Then press the bottom film to the cup body. Heat and pressurize it and wait for the glue layer to solidify before taking out the composite bamboo cup.

2. The method for producing a composite bamboo cup according to claim 1, characterized in that: In the step [1] of multi-layer composite of bamboo strip micro-sheets, the multi-layer bamboo strip micro-sheet coating is an alternating stack of bamboo strip micro-sheets and food-grade paperboard, wherein the bamboo strip micro-sheets are subjected to high-temperature hot pressing to arrange fibers in a directional manner, and the inner wall of the food-grade paperboard is coated with a waterproof coating.

3. The method for producing a composite bamboo cup according to claim 1, wherein: In the step [5], the bamboo tape layer is wound into the cup body, and the fan-shaped bamboo tape and the inner lining paper layer are wound in opposite directions with a certain spiral angle difference, and the angle difference is controlled so that the fan-shaped bamboo tape completely covers the seam of the inner lining paper layer.

4. The method for producing a composite bamboo cup according to claim 3, wherein: The fan-shaped bamboo belt and the inner lining paper layer are wound in opposite directions with a spiral angle difference of 10-15 degrees, wherein the spiral angle of the inner lining paper layer is 20-25 degrees, and the spiral angle of the fan-shaped bamboo belt is 35-40 degrees.

5. The method for producing a composite bamboo cup according to claim 1, wherein: In the step [1] of multi-layer composite of bamboo strip micro-sheets, 3-5 layers of bamboo strip micro-sheets are stacked alternately with a food-grade polyisocyanate emulsion adhesive, and hot-pressed at 120° C. to form the desired fan-shaped bamboo strips, with a coating amount of 15-25 g / m 2 , the thickness is controlled at 1-2mm.

6. The method for producing a composite bamboo cup according to claim 1, characterized in that: In the step [2] of preparing the inner lining layer, a 5 mm overlapping area is reserved at both ends of the fan.

7. The method for producing a composite bamboo cup according to claim 1, characterized in that: In step [4], the paper tape is wound into the inner lining layer, the preheating temperature is 50-60°C, the fan-shaped paper skin is continuously wrapped around the core mold at a spiral angle of 15-25°, the overlapping width of adjacent paper tapes is 3mm, and the additional glue coating amount at the head and tail joints of the paper tape is 20g / m 2 , heat the hot pressing wheel to 60℃ for 10-15s.

8. The method for producing a composite bamboo cup according to claim 1, characterized in that: In the step [5], the bamboo strip layer is wound into the cup body, the heating and softening temperature of the fan-shaped bamboo strip is 80-100° C.; the pressure applied when the fan-shaped bamboo strip and the lining paper layer are bonded to each other is 0.5-1.0 MPa; the oven temperature is 60-80° C., and the heating is carried out for 20-30 minutes.

9. The method for producing a composite bamboo cup according to claim 1, characterized in that: In step [6], the cup mouth is exposed 5-8 mm in the cup mouth, and a steam nozzle is used to perform circular spraying on the exposed portion of the cup mouth at 105°C and 0.1 MPa for 15-20 seconds to soften it, and food-grade starch glue with a solid content of 20%, a viscosity of 800 mPa·s, and a coating amount of 10 g / m 2 , forming a bonding transition layer.

10. The method for producing a composite bamboo cup according to claim 1, characterized in that: In the step [7] of cup bottom sealing, the coating amount of food grade polyisocyanate emulsion adhesive is 20g / m 2 , preheat to 50℃ to accelerate penetration.