Method of glue brushing for pulp molded products and pulp molded products

Abstract

The present application relates to a kind of pulp molded product glue brushing bonding method and pulp molded product, pulp molded product glue brushing bonding method, comprising the following steps: forming: forming the paper pulp tray board with multiple paper pulp trays distributed at intervals;Glue brushing: paper pulp tray board is brushed on paper pulp tray for the adhesive layer used for bonding paper card;Trimming: multiple paper pulp trays are formed by trimming paper pulp tray board;Place paper card;Machine bonding: make paper card and paper pulp tray bond together.The above-mentioned pulp molded product glue brushing bonding method, consider product glue brushing die number more, if each product is trimmed again and then brushed, take place more time-consuming, it is not convenient for employee operation, therefore the glue brushing procedure is reversed with trimming procedure, glue brushing before trimming process, reduce subsequent worker's take place time of single paper pulp tray, improve overall efficiency, can simply and quickly bond paper card and paper pulp tray together, production process efficiency is higher, can reduce pulp molded product packaging cost.

Description

Technical Field

[0001] This application relates to the field of paper-plastic technology, and in particular to a method for applying adhesive to molded pulp products and the molded pulp products themselves. Background Technology

[0002] Pulp molding (paper molding) is a technology that uses waste paper as raw material (including cardboard, waste cardboard, waste white edge paper, etc.), adds some moisture-proof or waterproof agents, and shapes paper products into specific forms using special molds on a molding machine. These products can be used as packaging liners for eggs, fruits, precision devices, fragile glass, ceramic products, handicrafts, etc., providing good cushioning and protection. In one type of pulp molding product, a bonding step is usually involved to ensure that the paper card and pulp tray are firmly bonded together to form a unified product structure, thereby creating a suitable containment space. The bonding of the paper card and pulp tray is a critical step, directly affecting the structural strength, durability, and overall quality of the product. However, due to the limitations of some processes, inefficiency, and high labor costs, the overall packaging cost increases exponentially. In existing processes, after the pulp tray is molded, an edge trimming process is required to remove excess material from the edges of the product before applying glue and bonding the paper card. If each product is trimmed before being glued, it takes a lot of time to handle and put away, which is inconvenient for employees and results in very low efficiency. Summary of the Invention

[0003] Therefore, it is necessary to provide a method for gluing and bonding pulp molded products that has high production efficiency and can reduce packaging costs, as well as the pulp molded products themselves. This invention mainly relates to a packaging process designed to bond paper cards and pulp trays together in a simple and quick manner.

[0004] This application provides a method for applying adhesive to molded pulp products, including the following steps:

[0005] Forming: Forming to form a pulp tray with multiple pulp trays spaced apart;

[0006] Applying adhesive: Apply an adhesive layer for bonding paper cards to the pulp tray on the pulp tray;

[0007] Trimming: Trimming the edges of the pulp trays to form multiple pulp trays;

[0008] Placing the paper card: Align the paper card and place it on the adhesive layer of the pulp tray;

[0009] Machine bonding: The adhesive layer is melted by heating and pressurizing the bonding equipment, so that the paper card and the pulp tray are bonded together.

[0010] In one embodiment, the adhesive application step uses a milky white water-based hot melt adhesive.

[0011] In one of the embodiments, the components of the water-based hot melt adhesive include: water-based urethane dispersion: 40%-42%, deionized water: 58%-60%, the pH value of 1% water solution of the water-based hot melt adhesive is 7-9, the initial boiling point of the water-based hot melt adhesive is 100℃, the secondary heating melting point is 120℃, and the dynamic viscosity is <250 mPa.s.

[0012] In one of the embodiments, in the glue brushing step, the position and size of the glue brushing screen printing plate is greater than 30mm and less than 50mm from the edge of the product paper pulp support.

[0013] In one of the embodiments, the mesh number of the glue brushing screen printing plate is selected as 80 mesh, the thickness of the glue brushing screen printing plate is 0.3mm, and the position thickness of the screen printing glue is 0.2mm.

[0014] In one of the embodiments, the thickness of the glue layer formed after the water-based hot melt adhesive is dry is controlled to be between 0.10-0.15mm.

[0015] In one of the embodiments, after the glue brushing, the glue layer on the paper pulp support is also subjected to a drying operation, and the drying mode is natural drying or heating drying.

[0016] In one of the embodiments, the heating drying adopts a drying line, the length of the heating section of the drying line should not be less than 5 meters, the drying temperature of the heating section is 80℃, and the speed of the drying line is 5m / min.

[0017] In one of the embodiments, in the natural drying, the air humidity is 40%-80%, the temperature is 15℃-30℃, and the drying time is 12-18 hours.

[0018] The application also provides a paper pulp molded product, which is formed by bonding the paper pulp support and the paper card by using the paper pulp molded product glue brushing and bonding method according to any one of the above embodiments.

[0019] The paper pulp molded product glue brushing and bonding method has more product glue brushing and die numbers, and if the glue brushing is performed after the cutting of each product, the taking and placing is time-consuming and inconvenient for the employees, therefore, the glue brushing process is adjusted with the cutting process, the glue brushing is performed before the cutting process, the taking and placing time of the workers on the single paper pulp support is reduced, the overall efficiency is improved, the paper card and the paper pulp support can be simply and quickly bonded together, the production process efficiency is high, and the packaging cost of the paper pulp molded product can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The figure is a step diagram of the paper pulp molded product glue brushing and bonding method according to an embodiment of the application. DETAILED DESCRIPTION

[0021] For the purpose of facilitating the understanding of the present application, in order to make the above-mentioned objects, features and advantages of the present application more apparent, the specific embodiments of the present application are described in detail below. In the following description, a number of specific details are set forth in order to provide a thorough understanding of the present application. The present application, however, can be practiced without resorting to the details specifically set forth. In other instances, well-known methods have not been described in detail in order to avoid unnecessarily obscuring the present application. The present application is intended to cover any and all modifications of the application within the scope of the claims. In this description, the meaning of "a plurality of" is at least two, for example, two, three, and the like, unless otherwise specifically defined. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used in this description, the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0022] The present application provides a pulp molded product brushing adhesive bonding method, please refer to Figure 1 The pulp molded product brushing adhesive bonding method comprises the following steps:

[0023] S1: forming: forming a pulp support plate with a plurality of pulp supports distributed at intervals;

[0024] A pulp support plate with a plurality of pulp supports distributed at intervals is formed by using a pulp molding process. Each pulp support is used to form a single pulp molded product later. In order to facilitate mass production, in the pulp molding manufacturing process, a large plate with a plurality of pulp supports is usually formed in batches, and then cut into single pulp supports, thereby improving production efficiency and reducing production cost.

[0025] In the forming process, it usually involves pulp preparation, forming mold manufacturing, and dehydration and setting steps.

[0026] Pulp preparation: Generally, pulp is made from waste paper or other plant fibers through processes such as disintegration and beating. During this process, parameters such as pulp concentration, fiber length and dispersity need to be controlled to ensure the forming quality.

[0027] Forming mold: The forming mold is the core component in the forming process, and its design determines the shape, size and precision of the pulp support. The mold usually adopts a porous structure to facilitate the deposition and filtration of the fibers in the pulp on the mold.

[0028] Dewatering and shaping: During the molding process, water in the pulp is expelled through the pores of the mold, while the fibers form a tight structure on the mold. This process requires controlling the dewatering speed and shaping pressure to ensure the strength and shape stability of the pulp tray.

[0029] In this application, the specific process of molding the pulp tray plate with multiple pulp trays spaced by the pulp molding process will be described in detail with reference to the prior art, and the application will not be described here.

[0030] S2: Glue brushing: Brushing a glue layer on the pulp tray of the pulp tray plate for bonding the paper card;

[0031] In the traditional process, the pulp tray plate is usually cut to form a single pulp tray, and then the worker brushes glue on the pulp tray and bonds the paper card. However, considering that the number of product brushing molds is relatively large, if each product is cut and then brushed, it takes a lot of time to pick up and put down, which is not convenient for employees to operate, so the brushing process is reversed with the cutting process to improve overall efficiency.

[0032] In this application, the glue layer for bonding the paper card is brushed on the pulp tray of the pulp tray plate before cutting, which facilitates batch brushing and improves brushing efficiency and production efficiency.

[0033] It should be noted that brushing glue is a key step of uniformly applying glue to the pulp tray, which directly affects the bonding effect of the pulp tray and the paper card. During the brushing process, it is necessary to ensure that the glue is evenly distributed on the pulp tray to avoid local glue deficiency or glue accumulation. This can be achieved by adjusting the parameters of the brushing equipment, selecting the appropriate glue concentration, and controlling the coating speed.

[0034] In one embodiment, the brushing step uses a water-based hot melt glue that appears milky white. For example, the composition of the water-based hot melt glue includes: water-based urethane dispersion: 40%-42%, deionized water: 58%-60%, the pH value of 1% water solution of the water-based hot melt glue is 7-9, the initial boiling point of the water-based hot melt glue is 100°C, the secondary heating melting point is 120°C, and the dynamic viscosity is <250 mPa.s. For example, in the brushing step, the size of the position of the brushing silk screen is greater than 30 mm and less than 50 mm from the edge of the product pulp tray plate. For example, the mesh of the brushing silk screen is selected to be an 80-mesh screen, the thickness of the brushing silk screen is 0.3 mm, and the thickness of the silk screen glue position is 0.2 mm. For example, the thickness of the glue layer formed after the water-based hot melt glue dries is controlled to be between 0.10-0.15 mm.

[0035] In order to improve the brushing effect and improve product quality, the applicant has researched the brushing glue. For example, the glue is an environmentally friendly water-based hot melt glue that appears milky white.

[0036] Ingredients: aqueous urethane dispersion (40-42%), deionized water (58-60%).

[0037] pH value: 7-9 (1% aqueous solution).

[0038] Initial boiling point: 100°C, second heating melting point at 120°C.

[0039] Kinetic viscosity: < 250 mPa.s.

[0040] In this way, the use of the above aqueous hot melt adhesive can better ensure the paper card and pulp to stick well, and during the brushing process, it can ensure the smooth brushing process, and it is not easy to appear leakage and pollution products.

[0041] In order to further control the quality of brushing, for example, the following process is used to control the amount of brushing, the position and size of the screen is greater than 30mm and less than 50mm from the edge of the brushed product. If the edge is too small, the glue backflow time is too short, and the glue will drip through the mesh onto the product, resulting in product defects. If the edge is greater than 50mm, the glue will be wasted, increasing the cost of glue.

[0042] After repeated testing and verification, the thickness of the glue layer formed after the glue is dry is controlled between 0.10-0.15mm, and the paper-plastic secondary heating bonded paperboard will not waste glue, and at the same time can stick the paperboard firmly. The mesh number is selected as 80 mesh, the silk screen thickness is 0.3mm, the silk screen glue position thickness is 0.2mm, and the brushing amount thickness is controlled between 0.08-0.15mm, and the thickness of the glue after drying is between 0.05-0.12mm, which meets the requirements of glue amount control.

[0043] In one embodiment, after applying the adhesive, the adhesive layer is dried on a pulp pallet using either natural drying or heated drying. For example, heated drying uses a drying line with a heating section at least 5 meters long, a heating temperature of 80 degrees Celsius, and a drying speed of 5 m / min. In natural drying, the air humidity is 40%-80%, the temperature is 15°C-30°C, and the drying time is 12-18 hours. In this embodiment, an environmentally friendly water-based hot melt adhesive is used, allowing for two drying methods: natural air drying, suitable for scenarios with ample delivery time and spacious facilities, with air humidity between 40%-80% and temperatures between 15°C-30°C, and a drying time of 12-18 hours; and heated drying, suitable for scenarios with short delivery times and limited production areas. Heated drying requires a drying line. The drying line must be at least 9 meters long, with a heating section at least 5 meters long, a drying temperature controlled at 80°C, and a drying speed of 5 m / min. Thus, since this application uses the aforementioned water-based hot melt adhesive, a suitable drying method can be selected according to the length of the construction period. Of course, the cost of natural drying is lower than that of heated drying, while the cost of heated drying is lower than that of natural drying.

[0044] S3: Trimming: Trimming the edges of the pulp trays to form multiple pulp trays;

[0045] Trimming is the step of cutting pulp trays into multiple individual pulp trays, and it is crucial to the dimensional accuracy and appearance quality of the product. The specific process of trimming is not described in detail here; please refer to existing technologies.

[0046] S4: Place the paper card: Align the paper card and place it on the adhesive layer of the pulp tray;

[0047] Align the paper card with the adhesive layer of the pulp tray to facilitate subsequent bonding of the paper card to the pulp tray.

[0048] S5: Machine bonding: The adhesive layer is melted by heating and pressurizing the bonding equipment, so that the paper card and the pulp tray are bonded together.

[0049] By heating and pressurizing the pulp tray and paper card using an adhesive bonding device, the adhesive layer melts and bonds together, thus ensuring the paper card and pulp tray are bonded together. For example, a pressure of 400N is applied to bond the pulp tray and paper card together. Specifically, the pulp product is placed in a fixture on a high-frequency table, the fixture is heated, and a pressure of 400N is applied to the paper card, causing the pulp tray and paper card to bond together.

[0050] The paper pulp molded product brushing adhesive bonding method considers that the product brushing adhesive demolding number is relatively large, if each product is brushed adhesive after cutting edge, the taking and placing is relatively time-consuming, and the employee operation is not convenient, therefore, the brushing adhesive process is inversed with the cutting edge process, the brushing adhesive is performed before the cutting edge process, the taking and placing time of the subsequent worker to the single paper pulp holder is reduced, the overall efficiency is improved, the paper card and the paper pulp holder can be simply and quickly bonded together, the production process efficiency is relatively high, and the paper pulp molded product packaging cost can be reduced.

[0051] The paper pulp molded product brushing adhesive bonding method is adopted, under the condition that the illumination is 900-1100 Lux, the inspection distance is 30±2 cm, the angle is ±30℃, the inspection time is 8-10 s, and whether the paper holder and the paper card are bonded together is visually observed; if more than 22 mm is not bonded together, the unqualified product is determined, if no more than 22 mm is not bonded together, the paper pulp holder and the paper card position are torn open, if the paper pulp holder is bonded, the qualified product is determined. It is found through inspection that, due to the adoption of the paper pulp molded product brushing adhesive bonding method, the qualified rate is 100%, and the process efficiency is extremely high.

[0052] Especially, the paper pulp molded product brushing adhesive bonding method can be used to pre-brush adhesive on the paper pulp holder plate and dry, and then cut the edge. Then it can be sent to the user, and the user can directly realize the bonding of the paper card and the paper pulp holder by combining the bonding equipment, which is extremely convenient for the user to use and improves the user convenience.

[0053] Moreover, the pulp molded product brushing adhesive bonding method combines the brushing adhesive method and the drying method, which not only improves the user convenience and the bonding strength.

[0054] The paper pulp molded product brushing adhesive bonding method can be used to pre-brush adhesive on the paper pulp holder plate and dry, and then cut the edge. Then it can be sent to the user, and the user can directly realize the bonding of the paper card and the paper pulp holder by combining the bonding equipment, which is extremely convenient for the user to use and improves the user convenience.

[0055] It should be noted that the present application mainly relates to a packaging process, which aims to bond paper and paper pulp holders together in a simple and fast way.

[0056] 1. Design idea.

[0057] Paper plastic product brushing adhesive → drying → packaging product → placing paper card → machine bonding → boxing.

[0058] 2. Glue performance.

[0059] The glue is an environmentally friendly water-based hot melt glue, which is milky white.

[0060] Composition: water-based urethane dispersion (40%-42%), deionized water (58%-60%).

[0061] pH value: 7-9 (1% aqueous solution).

[0062] Initial boiling point: 100°C, second heating melting point at 120°C.

[0063] Dynamic viscosity: < 250 mPa.s.

[0064] 3. Control the amount of glue.

[0065] The size of the screen position is greater than the edge of the glue product by 30 mm and less than 50 mm. If the edge is too small, the glue backflow time is too short, and the glue will drip onto the product through the mesh, causing product defects. If the edge is greater than 50 mm, the glue is wasted, increasing the cost of glue.

[0066] After repeated testing and verification, the thickness of the glue after drying is controlled between 0.10-0.15 mm, and the paper-plastic secondary heating of the paperboard will neither waste glue nor stick the paperboard firmly. The mesh of 80 mesh is selected, the thickness of the silk screen is 0.3 mm, the thickness of the silk screen glue position is 0.2 mm, and the thickness of the glue is just controlled between 0.08-0.15 mm. After the glue dries, the thickness is between 0.05-0.12 mm, meeting the requirements of glue control.

[0067] 4. Mould number.

[0068] Based on the size of the machine's operating plane, combined with the size of the product, the overall mould number is determined to improve productivity and reduce costs.

[0069] 5. Adjust the process sequence.

[0070] Considering that the product has a relatively large number of glue brushing moulds, if each product is cut and then brushed with glue, it will take a lot of time to pick and place, which is not convenient for employees to operate. Therefore, the brushing process is adjusted with the cutting process to improve overall efficiency.

[0071] 6. Drying method selection.

[0072] Because the glue we choose is a fast-drying type, the drying method can be selected in two ways. The first is natural air drying, which is suitable for models with ample delivery time and spacious site. The air humidity is 40%-80%, the temperature is 15°C-30°C, and the drying time is 12-18 hours. The second is heated drying, which is suitable for models with short delivery time and narrow site. Heated drying requires the use of a drying line. The length of the drying line should not be less than 9 meters, the middle heating section should not be less than 5 meters, the drying temperature should be controlled at 80°C, and the drying line speed should be 5 m / min.

[0073] 7. Product packaging method: pulp products are placed in the jig on the high-frequency table, the product is placed, the jig is heated, a 400N is applied to the paper card, and the pulp holder and the paper card are bonded together.

[0074] 8. Inspection standard: under the condition of illumination of 900-1100 Lux, the inspection distance is 30±2 cm, the angle is ±30 °, the inspection time is 8-10 s, and the paper holder and the paper card are bonded together. If more than 22 mm is not bonded together, it is judged to be unqualified product, if there is no more than 22 mm, the paper pulp holder and the paper card position are torn open, if the paper pulp holder is bonded, it is judged to be qualified.

[0075] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application. It should be noted that the "in an embodiment of the present application", "for example", "such as" and the like of the present application are intended to illustrate the present application, and are not used to limit the present application. The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method of sizing and bonding a pulp molded product, characterized by, It comprises the following steps: Molding: molding to form a pulp tray plate with a plurality of pulp trays distributed at intervals; Glue brushing: brushing a glue layer for bonding paper cards on the pulp trays on the pulp tray plate; wherein the glue brushing uses a milky white water-based hot melt adhesive, the composition of the water-based hot melt adhesive comprises: water-based urethane dispersion: 40%-42%, deionized water: 58%-60%, the pH value of 1% water solution of the water-based hot melt adhesive is 7-9, the initial boiling point of the water-based hot melt adhesive is 100℃, the secondary heating melting point is 120℃, and the dynamic viscosity is <250mPa.s; the size of the position of the glue brushing silk screen is greater than 30 to 50mm from the edge of the pulp tray plate of the glue brushing product; the mesh number of the glue brushing silk screen is selected to be 80 mesh, the thickness of the glue brushing silk screen is 0.3mm, and the position thickness of the silk screen glue is 0.2mm; the thickness of the glue layer formed after the water-based hot melt adhesive glue dries is controlled to be between 0.10-0.15mm; after the glue brushing, the glue layer on the pulp tray plate is also subjected to drying operation, and the drying mode is natural air drying or heating drying; the heating drying adopts a drying line, the length of the heating section of the drying line should not be less than 5 meters, the drying temperature of the heating section is 80℃, and the drying line speed is: 5m / min; in the natural air drying, the air humidity is 40%-80%, the temperature is 15℃-30℃, and the drying time is 12-18 hours; Edge cutting: edge cutting to form a plurality of pulp trays; Placing paper cards: aligning and placing paper cards at the glue layer position of the pulp trays; Machine bonding: using bonding equipment to heat and press to melt the glue layer, so that the paper cards and the pulp trays are bonded together.

2. A pulp molded product, characterized by, The paper pulp molded product glue brushing and bonding method according to claim 1 is used to bond the pulp tray plate and the paper cards to form the paper pulp molded product.

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