Composite thermoformed tableware and method for manufacturing same

Abstract

The application provides a composite thermoforming tableware and a preparation method thereof. The preparation method of the composite thermoforming tableware comprises sequentially performing a preheating step, a compounding step and a thermoforming step. The preheating step comprises heating multiple layers of forming materials at a temperature of 35-150 DEG C, wherein the forming materials comprise one or more than two of paper, plastic and inorganic layer. The compounding step comprises stacking the preheated forming materials to form a composite material. The thermoforming step comprises hot-pressing the composite material at a temperature of 80-150 DEG C and a pressure of 0.05-0.5 MPa to form a three-dimensional blank. The tableware is formed by thermoforming multiple layers of the same material or different materials to form a composite structure, so that the thickness and strength of the tableware are higher. The method has a simple operation process, avoids complex and complicated processes, and better controls the production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tableware, in particular to a composite thermoforming tableware and a preparation method thereof. BACKGROUND

[0002] Paper pulp molded tableware is a kind of tableware popular in the market in recent years, which has the advantages and characteristics of replacing part of plastic tableware and is an environmentally friendly material widely used in food packaging. However, the production process of paper pulp molded tableware is relatively complicated. Generally, the raw materials need to be crushed to form a pulp solution with a certain concentration, the water is then sucked away by a vacuum system to form a wet blank, and then the wet blank is dried by high-temperature hot pressing to form a dry product. The manufacturing cost of paper pulp molded tableware is relatively high, and many supporting processes are required, such as vacuum pulp suction and high-pressure drying forming. In addition, the thickness and strength of paper pulp molded tableware have an important influence on the performance of paper pulp molded tableware. If the thickness and strength cannot meet the requirements, the paper pulp molded tableware will be soft and difficult to hold food when used.

[0003] Plastic tableware is a material commonly used in the catering industry, which is directly in contact with food. With the increasing awareness of environmental protection, people realize that most of the plastic tableware on the market is not biodegradable, such as PP, PET, PE, etc., and most of the plastic tableware has a high manufacturing cost. At present, there are also tableware made of biodegradable plastic, such as PLA tableware, which has industrial biodegradability, but the price is high, and the market usage rate is relatively low. SUMMARY

[0004] The first object of the present application is to provide a composite thermoforming tableware preparation method with simple manufacturing process, low cost and easy thickness and strength control.

[0005] The second object of the present application is to provide a composite thermoforming tableware prepared by the above preparation method.

[0006] In order to achieve the above-mentioned first object, the composite thermoforming tableware preparation method provided by the present application comprises sequentially performing a preheating step, a compounding step and a thermoforming step; the preheating step comprises heating a plurality of layers of molding materials at a temperature of 35℃ to 150℃, the molding materials comprising one or more of paper, plastic and inorganic layer; the compounding step comprises stacking the preheated molding materials to form a composite material; and the thermoforming step comprises hot pressing the composite material at a temperature of 80℃ to 150℃ and a pressure of 0.05MPa to 0.5MPa to form a three-dimensional shaped blank.

[0007] Further, the molding material has self-adhesion, and the molding material is in a semi-melted state in the preheating step and is bonded to another molding material in a semi-melted state in the compounding step.

[0008] A further embodiment involves applying an adhesive between two adjacent molding materials during the preheating step. The adhesive comprises, by mass fraction, 20%–50% homopolymer polyacrylate and 50%–80% silica pigment, or by mass fraction, 50%–95% PVA and 5%–50% starch; the amount of adhesive used is 3 g / m³. 2 ~15g / m 2 .

[0009] A further method involves applying an oil-resistant layer to the inner and outer surfaces of the three-dimensional preform after the thermoforming step. The oil-resistant layer comprises, by mass fraction, 1%–50% starch, 50%–98% polyacrylate emulsion, and 1%–3% alkyl ketene dimer emulsion, with a coating amount of 0.1 g / m³. 2 ~2g / m 2 .

[0010] A further option is that the preparation method includes a drying step, which is carried out between the preheating step and the thermoforming step. The drying step dries the composite material at a temperature of 100℃ to 200℃.

[0011] A further proposed design involves a composite thickness of 100 μm to 10 mm for the three-dimensional shaped billet, a load-bearing capacity of 0.9 kgf to 2.0 kgf for the three-dimensional shaped billet, and an interlayer bonding force greater than 120 J / m for the three-dimensional shaped billet. 2 .

[0012] A further approach involves using a laminating machine, which includes a transfer mechanism, a preheating zone, a laminating zone, and a thermoforming zone. The transfer mechanism includes at least two unwinding devices, the preheating zone includes at least two heating rollers, the laminating zone includes multiple extrusion rollers, and the thermoforming zone includes a molding device. The molding material is transferred to the preheating zone via the unwinding devices, the heating rollers heat the molding material, the extrusion rollers laminate the multi-layer molding material, and the molding device thermoforms the laminated molding material.

[0013] To achieve the second objective mentioned above, the composite thermoformed tableware provided by the present invention is prepared by the above-described preparation method. The tableware includes at least two layers of molding materials, which are stacked to form a composite structure. The molding materials include one or at least two of paper, plastic and inorganic materials.

[0014] A further option is to provide an adhesive between two adjacent molding materials, the adhesive comprising 20%–50% homopolymer polyacrylate and 50%–80% silica pigment by mass fraction, or the adhesive comprising 50%–95% PVA and 5%–50% starch by mass fraction; the amount of adhesive used is 3 g / m³. 2 ~15g / m 2The inner and outer surfaces of the tableware are coated with an oil-proof layer, the oil-proof layer comprises 1-50% of starch, 50-98% of polyacrylate emulsion and 1-3% of alkyl enone dimer emulsion by mass fraction, and the coating amount of the oil-proof layer is 0.1-2 g / m 2 . 2

[0015] Further, the tableware comprises a handle and a main body part, the handle and the main body part are integrally connected, and an inner circular arc is formed at the corner between the handle and the main body part.

[0016] The tableware provided by the application is formed into a composite structure by hot forming of multiple layers of the same material or different materials, and the obtained tableware has higher thickness and higher strength. In the preheating step, heating causes the self-adhesive material to generate adhesion, and the self-adhesive material is bonded with other formed materials, or heating causes the obtained composite material to reduce moisture, thereby improving the liquid absorption of the composite material, facilitating better bonding of the composite material by using an adhesive; the preparation method directly obtains the product by preheating and then hot forming, the product surface is smooth and wrinkle-free, and the operation process is simple, without complex and complicated procedures, thereby better controlling the production cost.

[0017] Further, the preheating step causes the self-adhesive formed material to generate adhesion, and the formed material and another formed material are more conveniently and quickly bonded and stacked to form a composite structure.

[0018] In addition, the adhesive is used to bond the formed material without adhesion to form a composite structure, thereby ensuring the thickness of the product and the bonding strength of the composite material, and avoiding delamination of the final tableware product.

[0019] In addition, the oil-proof layer is added to the tableware to provide good waterproof and oil-proof effect, thereby avoiding leakage of the tableware when the tableware is used to hold food heated by the tableware; and the oil-proof layer does not contain fluorine and PFAS components, and is more in line with food safety requirements and friendly to the environment.

[0020] Further, the preparation method comprises a drying step, the drying step is performed between the preheating step and the hot forming step, and the drying step dries the composite material, and the drying temperature is 100-200 DEG C.

[0021] It can be seen that the drying step before the hot forming step better controls the water content of the composite material, improves the liquid absorption of the composite material, makes the composite material more uniformly absorb the adhesive, ensures the interlayer bonding strength of the composite material, and improves the forming rate of the blank.

[0022] In addition, the thickness and strength of the tableware ensure that the daily use performance of the tableware is more in line with the requirements of consumers and the use experience is better.

[0023] ​The application realizes automatic production of tableware by a compound machine, further makes the preparation process of tableware simpler, and effectively improves production efficiency.

[0024] In addition, an inner arc is formed at the corner between the handle and the main body, so as to avoid cracks in the product after molding. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a composite structure schematic diagram of the first embodiment of the composite thermoforming environment-friendly tableware of the application.

[0026] Figure 2 is a composite structure schematic diagram of the second embodiment of the composite thermoforming environment-friendly tableware of the application.

[0027] Figure 3 is a composite structure schematic diagram of the third embodiment of the composite thermoforming environment-friendly tableware of the application.

[0028] Figure 4 is a composite structure schematic diagram of the fourth embodiment of the composite thermoforming environment-friendly tableware of the application.

[0029] Figure 5 is a front view of the composite thermoforming environment-friendly tableware as a spoon.

[0030] Figure 6 is a front view of the composite thermoforming environment-friendly tableware as a fork.

[0031] Figure 7 is a front view of the composite thermoforming environment-friendly tableware as a knife.

[0032] Figure 8 is a flow chart of the preparation method embodiment of the composite thermoforming environment-friendly tableware of the application.

[0033] The application is further described below in combination with the drawings and embodiments. DETAILED DESCRIPTION

[0034] The composite thermoforming tableware comprises at least two layers of forming materials, the forming materials are stacked to form a composite structure, and the forming materials comprise one or at least two or more of paper, plastic and inorganic materials. In the preparation process, if the forming materials have self-adhesion, the forming materials are preheated to make the forming materials have adhesion, so as to facilitate adhesion with another forming material to form the composite structure. If the forming materials do not have self-adhesion, an adhesive is arranged between the two adjacent layers of forming materials, the adhesive comprises 20% to 50% homopolymer acrylate and 50% to 80% silicon dioxide pigment by mass fraction, or the adhesive comprises 50% to 95% PVA and 5% to 50% starch adhesive by mass fraction, and the amount of the adhesive is 3g / m 2 ~ 15g / m2 The inner and outer surfaces of the tableware are coated with an oil-proof layer, which comprises 1-50% starch, 50-98% polyacrylate emulsion and 1-3% alkyl enone dimer emulsion AKD by mass fraction, and the coating amount of the oil-proof layer is 0.1-2 g / m 2 2 .

[0035] Referring to Figure 1 , the tableware 1 in the first embodiment comprises a first forming material 11, a second forming material 12 and a third forming material 13, which are stacked in a laminated manner along the vertical direction, wherein the forming material of the second forming material 12 in the middle layer has self-adhesion, and the forming materials between the layers are directly bonded. The inner and outer surfaces of the tableware are respectively coated with an oil-proof layer 14.

[0036] Referring to Figure 2 , the tableware in the second embodiment comprises a first forming material 21, a second forming material 22 and a third forming material 23, which are stacked in a laminated manner along the vertical direction, wherein the second forming material 22 in the middle layer has self-adhesion, and the forming materials between the layers are directly bonded. The inner and outer surfaces of the tableware are not coated with an oil-proof layer.

[0037] Referring to Figure 3 , the tableware in the third embodiment comprises a first forming material 31, a second forming material 31 and a third forming material 31, which are stacked in a laminated manner along the vertical direction. Each layer of forming material does not have self-adhesion, and the forming materials between the layers have a bonding layer 34. The inner and outer surfaces of the tableware are respectively coated with an oil-proof layer 33.

[0038] Referring to Figure 4 , the tableware in the fourth embodiment comprises a first forming material 41, a second forming material 42 and a third forming material 43, which are stacked in a laminated manner along the vertical direction. Each layer of forming material does not have self-adhesion, and the forming materials between the layers have a bonding layer 44. The inner and outer surfaces of the tableware are not coated with an oil-proof layer.

[0039] ​The tableware structure of the first to fourth embodiments can be used for different kinds of tableware, and can be used in direct contact with dry food, wet food, and oily food. During the preparation of the tableware, whether to coat an oil-proof layer on the three-dimensional shaped blank can be selected according to the final performance of the tableware. If the tableware is not required to have a waterproof and oil-proof effect, the oil-proof layer does not need to be coated on the three-dimensional shaped blank. If the tableware is required to have a waterproof and oil-proof effect, the oil-proof layer is coated on the three-dimensional shaped blank.

[0040] Referring to Figure 5 , the tableware can be a spoon, which comprises a handle 51 and a main body 52, the handle 51 and the main body 52 are integrally connected, and an angle 53 is formed between the handle 51 and the main body 52, the angle 53 is an inner arc, and the inner arc is inwardly recessed towards the inside of the tableware. An inner arc with a certain radius of curvature is formed between the handle 51 and the main body 52, so that cracks are avoided at the position of the inner arc after the mold pressing. Figure 5 When the tableware is a spoon, the main body 52 is an oval-shaped recessed support block, which can hold a small amount of liquid and solid. Referring to Figure 6 When the tableware is a fork, the main body 52 is in the shape of a fork, and the angle 53 between the handle 51 and the main body 52 is an inner arc. Figure 7 When the tableware is a knife, a plurality of serrations 54 are formed on the main body 52, and the angle 53 between the handle 51 and the main body 52 is an inner arc. In addition to the spoon, the fork and the knife, the tableware can also be a bowl, a dish, a basin, etc.

[0041] The forming material is selected from one or at least two of paper, plastic and inorganic material, wherein the plastic includes ordinary plastic and bio-plastic, so the forming material can be selected from one or at least two of paper, ordinary plastic, bio-plastic and inorganic material. The main material of the paper is plant fiber, and the paper, bio-plastic and inorganic material are degradable and environmentally friendly. Preferably, when one of the forming material is ordinary plastic, the other of the forming material is degradable material.

[0042] The specific index characteristics of the paper are shown in Table 1.

[0043] Table 1

[0044]

[0045] In Table 1, the number of layers of the paper is 1-5 layers, so that in the tableware, the one layer of the forming material with the material of the paper is formed by stacking 1-5 layers of paper, further ensuring the thickness and strength of the tableware. Since the forming material for preparing the tableware can be purchased from the market as a finished product, the finished product has 1-5 layers of paper, and the forming material with multiple layers of stacking is purchased again for composite stacking, so that the strength of the tableware is better, and the preparation process is simpler.

[0046] The paper can include one or both of a first plant fiber and a second plant fiber, the first plant fiber being one of wood pulp, bagasse pulp, and straw pulp, and the second plant fiber being one of reed pulp, bamboo pulp, and palm pulp.

[0047] The specific index characteristics of the bio-plastic are shown in Table 2.

[0048] Table 2

[0049]

[0050] The bio-plastic of each layer can be one of PLA, PBAT, PBS, or PBSA, and the bio-plastic is biodegradable, so that the obtained tableware is more environmentally friendly.

[0051] The specific index characteristics of the common plastic are shown in Table 3.

[0052] Table 3

[0053]

[0054] The specific index characteristics of the inorganic material are shown in Table 4.

[0055] 10Table 4

[0056]

[0057]

[0058] The inorganic material is assembled into a plate shape in the process of preparing the tableware, so that the inorganic material is easily adhered to other molding materials.

[0059] If one of the molding materials of the tableware has self-adhesion, the molding materials can be adhered without using an adhesive between the layers. The molding materials having self-adhesion include PLA, PBAT, PE, PP, PET, PVDC, and PBS.

[0060] If the molding materials of the layers do not have self-adhesion, an adhesive is provided between the adjacent two layers of the molding materials, and the adhesive serves to bond the adjacent two layers of the molding materials. The adhesive includes 20% to 50% of homopolymer acrylate and 50% to 80% of silica pigment by mass fraction, and the amount of the adhesive is 3 g / m 2 ~ 15 g / m 2 . Preferably, the adhesive includes 30% of homopolymer acrylate and 70% of silica pigment, and the amount of the adhesive is 8 g / m 2 . As another embodiment, the adhesive includes 50% to 95% of PVA and 5% to 50% of starch by mass fraction.

[0061] The specific index characteristics of the adhesive are shown in Table 5.

[0062] Table 5

[0063] Solid content 52％～55％ Viscosity (2# rotor, 100 rpm, 20°C) 150 mPa.s ~ 350 mPa.s Density 1.15 g / cm 3 ]]>

[0064] The oil-proof layer comprises 1% to 50% starch, 50% to 98% polyacrylate emulsion and 1% to 3% alkyl ketene dimer emulsion by mass fraction, and the coating amount of the oil-proof layer is 0.1 g / m 2 2 g / m 2 . Preferably, the oil-proof layer comprises 20% to 50% starch, 48% to 78% polyacrylate emulsion and 2% alkyl ketene dimer emulsion, and the coating amount of the oil-proof layer is 1 g / m 2 . The oil-proof layer can be arranged on the inner and outer surfaces of the tableware.

[0065] The specific index characteristics of the starch in the oil-proof layer are shown in Table 6.

[0066] Table 6

[0067] Concentration 5％～15％ Viscosity (2# rotor, 60 rpm, 25°C) 20 mPa.s ~ 150 mPa.s

[0068] The specific index characteristics of the polyacrylate emulsion in the oil-proof layer are shown in Table 7.

[0069] Table 7

[0070] Index Characteristic value Solid content 20％～23％ pH 5.0～7.0 Density 1.02 g / ml ~ 1.10 g / ml Molecular weight 50，000～350，000 Viscosity 50 mPa.s ~ 200 mPa.s Average particle diameter 50 nm ~ 100 nm

[0071] The specific index characteristics of the alkyl ketene dimer emulsion (AKD) in the oil-proof layer are shown in Table 8.

[0072] Table 8

[0073] Index Characteristic value Solid content 14％～16％ pH 3.0～5.0 Density 1.02 g / ml ~ 1.10 g / ml Ionicity Positive Molecular weight 50，000～350，000 Viscosity 10 mPa.s ~ 20 mPa.s Average particle diameter 0.5 μm ~ 2 μm

[0074] See Figure 8The preparation method of the composite thermoformed tableware of the present application comprises the following steps in sequence: a preheating step, an adhesive coating step, a composite step, a finishing step, a drying step, a die cutting step, a thermoforming step and an oil-proof layer coating step. The preparation method of the composite thermoformed tableware of the present application is performed by a composite machine, which is provided with a transmission mechanism, a preheating zone, an adhesive coating zone, a composite zone, a finishing zone, a drying zone, a die cutting zone and a thermoforming zone corresponding to each step. The transmission mechanism comprises at least two unwinding devices, and the roll-shaped forming material is transferred by rolling of the unwinding devices. The adhesive coating zone comprises a plurality of coating rollers coated with adhesive. The composite zone comprises one or more extrusion rollers through which the multi-layer forming material passes. The finishing zone comprises a plurality of grinding devices. The drying zone comprises a plurality of drying devices. The die cutting zone comprises a die cutting device for shearing the composite material. The thermoforming zone comprises a die pressing device for hot pressing the composite material of a certain size.

[0075] The preheating step specifically comprises: transferring the multi-layer forming material to the preheating zone through a plurality of unwinding devices, one layer of forming material corresponding to one unwinding device. In the preheating zone, the surface of each layer of forming material is heated by a heating roller at a temperature of 35℃ to 150℃ to a set temperature of 100℃ to 200℃, wherein the heating temperature can be adjusted according to the material quality of the forming material; preferably, the heating temperature is 150℃; and the heating mode can be hot oil heat exchange or steam heat exchange.

[0076] If the forming material has self-adhesion, the adhesive coating step is not required, and the forming material is directly subjected to the composite step after the preheating step, with the surface of the forming material being in a semi-melted state.

[0077] If the forming material does not have self-adhesion, the forming material needs to be subjected to the adhesive coating step before the composite step. The adhesive coating step specifically comprises: coating the outer surface of the first coating roller with adhesive, and contacting the adhesive surface of the composite material with the outer surface of the first coating roller to coat the adhesive onto the adhesive surface of the composite material, and adhering the adhesive surface to another forming material by the adhesive.

[0078] The composite step specifically comprises: when the multi-layer forming material passes through the extrusion roller, the multi-layer forming material is adhered under the pressure of the extrusion roller to form a composite material. In the above composite step, the number of layers of the forming material can be 2 to 10 layers; the conveying speed of the extrusion roller is 30m / min to 150m / min; and the pressure of the extrusion roller is 10psi to 200psi. The thickness of the composite material is 100μm to 10mm, and the interlayer bonding force of the composite material is greater than 120J / m 2 ~15g / m 2; or the adhesive comprises 50% to 95% PVA and 5% to 50% starch.

[0079] The finishing step specifically refers to grinding or printing the composite material in the finishing area by a finishing tool.

[0080] The drying step specifically refers to drying the composite material in the drying area, and the drying temperature is 100-200 DEG C, and the heating mode is hot oil heat exchange or steam heat exchange.

[0081] The die cutting step specifically refers to shearing the composite material by a die cutting device to form a plurality of small pieces with a certain size.

[0082] The thermoforming step specifically refers to: after the composite material is cut into a required specification by the die cutting step, the composite material enters a thermoforming area, and a set-shaped mold pressing device such as a mold with a specific shape is used to perform hot pressing to form a three-dimensional shaped blank body. In the thermoforming step, the hot pressing speed is 60 pcs / min, the hot pressing temperature is 80-150 DEG C, the hot pressing pressure is 0.05-0.5 MPa, the hot pressing time is 0.5-2 s, and the heating mode is electric heating. Preferably, the hot pressing temperature is 100 DEG C, the hot pressing pressure is 0.15 MPa, and the hot pressing time is 1.5 s.

[0083] After the thermoforming step, a three-dimensional shaped blank body is obtained, and according to the final function of the tableware, the tableware can be coated with an oil-proof layer to have a waterproof and oil-proof effect; or the oil-proof layer coating step can be omitted. The oil-proof layer coating step specifically refers to immersing the three-dimensional shaped blank body in a container containing an oil-proof agent, so that the inner and outer surfaces of the blank body form a coating layer. The oil-proof layer comprises 20-50% starch, 48-78% polyacrylate emulsion and 2% alkyl alkene ketone dimer emulsion by mass fraction, and the coating amount of the oil-proof layer is 1 g / m 2 The coating time is 1-5 s. After the oil-proof layer is coated, the tableware coated with the oil-proof agent is dried, the drying temperature is 100-180 DEG C, and the drying time is 5-10 s.

[0084] Referring to Figure 8 After the preheating step and the compounding step are completed, the die cutting and thermoforming steps of the composite material can be directly performed.

[0085] The composite thermoformed tableware of the application embodies the performance of the tableware by testing the water resistance, oil resistance, load bearing performance and interlayer bonding force.

[0086] The water resistance test is performed by testing the time when the tableware resists immersion in 85 DEG C water, and the specific test method is as follows: the tableware is immersed in 85 DEG C water, and the tableware is taken out every certain time to observe whether penetration occurs. If penetration occurs, the immersion time is the time when the tableware resists immersion.

[0087] The test of oil resistance is to test the time of the tableware resisting immersion in oil at 85°C. Specifically, the tableware is immersed in oil at 85°C, and the tableware is taken out every certain time to observe whether penetration occurs. If penetration occurs, the time of immersion is the time of the tableware resisting immersion.

[0088] The load-bearing test kgf is used to represent the maximum pressure that the tableware can bear. The higher the value, the stronger the product is in resisting bending and breaking. The load-bearing test before immersion is to continuously apply a load to the tableware, and when the tableware bends, the weight of the load on the tableware is the maximum pressure that the tableware can bear. The load-bearing test after immersion is to test the maximum pressure value after 10 minutes of immersion.

[0089] The product interlayer bonding force is used to represent the adhesion between the layers of the tableware. The higher the value, the stronger the adhesion between the layers of the product, and the stronger the performance of resisting delamination. The test method of the product interlayer bonding force can be according to the test method recorded in the American Paper Industry International Standard TAPPI T569.

[0090] The present application will be further described in conjunction with specific examples to better understand the present application.

[0091] The present application provides 16 groups of examples and 5 comparative examples. The preparation methods of the 16 groups of examples are substantially the same, and the differences are shown in the following tables. The selection of the material for each layer of the examples 1 to 10 and the proportion of the adhesive and the oil-proof layer components are shown in table 9, the selection of the material for each layer of the examples 11 to 13 and the proportion of the adhesive and the oil-proof layer components are shown in table 10, the selection of the material for each layer of the examples 14 to 16 and the proportion of the adhesive and the oil-proof layer components are shown in table 11, and the selection of the material for each layer of the comparative examples 1 to 5 is shown in table 12. In the above tables, the number of adhesive layers is not equal to the number of adhesive layers used. Since some of the molding materials have self-adhesion, the molding materials with self-adhesion do not need adhesive with other molding materials. For example, the adhesive g / m2in the examples with 0 in the above table is not used. 2

[0092] Table 9

[0093]

[0094]

[0095] Table 10

[0096]

[0097] Table 11

[0098] ​

[0099]

[0100] Table 12

[0101]

[0102] The tableware in Examples 1 to 16 and Comparative Examples 1 to 5 were tested.

[0103] The performance test results of the tableware in Examples 1 to 16 and Comparative Examples 1 to 5 are shown in Table 13.

[0104] Table 13

[0105]

[0106]

[0107] From Tables 9 to 13, it can be seen that the tableware in Example 4 and Example 5 differ in the number of layers, with three layers in Example 4 and four layers in Example 5. The tableware in Example 10 and Example 13 differ in the number of layers, with three layers in Example 10 and four layers in Example 13. The tableware in Example 15 and Example 16 differ in the number of layers, with three layers in Example 15 and four layers in Example 16. The water resistance and oil resistance of the tableware with four layers of forming material are about the same as those of the tableware with three layers of forming material. The load-bearing performance of the tableware with four layers of forming material is better than that of the tableware with three layers of forming material, but the interlayer adhesion of the tableware with three layers of forming material is better than that of the tableware with four layers of forming material, so the interlayer strength of the tableware with three layers of forming material is better, and the tableware preferably has three layers of forming material.

[0108] Comparing Example 10 and Example 13, the amount of adhesive used differs between the two examples. Increasing the coating amount of the adhesive can improve the interlayer adhesion of the product, while also enhancing the water resistance and oil resistance of the product. The adhesive is preferably used in an amount of 8 g / m2. 2 The coating amount is based on the stable parameters that can be provided by the coating production equipment.

[0109] The tableware in Examples 6 to 9 does not have an oil-proof layer, and the tableware in Examples 6 to 9 is compared with the tableware in Example 4, respectively. The load-bearing performance of the tableware without an oil-proof layer is significantly lower than that of the tableware with an oil-proof layer, indicating that the oil-proof layer can reduce the leakage of the tableware.

[0110] Compared with Example 1 and 3, Example 2 and 4, Example 14 and 15, increasing the proportion of starch in the oil-proof layer can improve the load-bearing performance of the product, but excessive increase in the proportion will reduce the water resistance of the product. A suitable amount can meet the performance of both aspects.

[0111] Compared with Comparative Example 1, the tableware in Examples 1 to 16 has high stiffness load-bearing performance and interlayer bonding force, which is better than ordinary single-layer paperboard tableware on the market. Compared with Comparative Examples 2 to 4, the stiffness load-bearing performance of the tableware in Examples 1 to 16 before immersion is comparable to that of existing plastic tableware, and the performance of some examples is even better than that of existing plastic tableware, indicating that the tableware of the examples can replace existing plastic tableware as disposable tableware. Compared with Comparative Example 5, the stiffness load-bearing performance of the tableware in Examples 1 to 16 before and after immersion decreases at a lower rate than existing paper molded tableware, and has better strength stability.

[0112] Further, compared with the tableware of Comparative Examples 1 to 5, the performance improvement effect of the tableware in Example 4 is shown in Table 14.

[0113] Table 14

[0114]

[0115]

[0116] As can be seen from Table 14, the composite thermoformed tableware of Example 4 has a large improvement in performance compared with existing tableware, and has good biodegradability and can be home composted.

[0117] Finally, it should be emphasized that the above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0118] Industrial applicability

[0119] The present application is used for preparing a composite thermoforming tableware, which can be a knife, a fork, a spoon, a bowl or a plate and the like, and can be used for containing food or beverage or for the case of using the tableware for dining. The composite thermoforming tableware of the present application is formed by thermoforming multiple layers of the same material or different materials, so that the thickness and strength of the tableware are higher. In the preheating step, the heating makes the self-adhesive material produce adhesion, bond with other forming materials, or the heating makes the moisture of the obtained composite material decrease, improves the absorption of the composite material to liquid, facilitates the better adhesion of the composite material by using the adhesive. The preparation method directly obtains the product by preheating and then thermoforming, the product surface is smooth without wrinkles, and the operation process is simple, without complex and complicated procedures, and the production cost is better controlled. By selecting an environmentally friendly material as the forming material, an environmentally friendly composite tableware can be prepared.

Claims

1. A method for preparing composite thermoformed tableware, characterized in that: The preparation method includes a preheating step, a compounding step, and a thermoforming step performed sequentially. The preheating step includes heating the multilayer molding material at a temperature of 35℃ to 150℃, wherein the molding material is paper; The composite step involves stacking the preheated molding materials to form a composite material. The thermoforming step includes hot-pressing the composite material at a temperature of 80°C to 150°C and a pressure of 0.05 MPa to 0.5 MPa to form a three-dimensional blank. The thermoforming step includes: cutting the composite material into the required specifications through a die-cutting step, then putting the composite material into a thermoforming zone, where a molding device of a set shape is used for hot pressing in the thermoforming zone to form a three-dimensional blank. The heating in the preheating step makes the self-adhesive material sticky or reduces the moisture content of the composite material, thereby improving the composite material's absorbency to liquids. After the thermoforming step, the process further includes: applying an oil-resistant layer to the inner and outer surfaces of the three-dimensional preform, wherein the oil-resistant layer comprises 1%–50% starch, 50%–98% polyacrylate emulsion and 1%–3% alkyl ketene dimer emulsion by mass fraction.

2. The method for preparing composite thermoformed tableware according to claim 1, characterized in that: The molding material is self-adhesive, and the molding material is bonded to another molding material in a semi-molten state during the preheating step.

3. The method for preparing composite thermoformed tableware according to claim 1, characterized in that: The preheating step further includes applying an adhesive between two adjacent molding materials; the adhesive comprises 20%–50% homopolymer polyacrylate and 50%–80% silica pigment by mass fraction, or comprises 50%–95% PVA and 5%–50% starch by mass fraction; the amount of adhesive used is 3 g / m³. 2 ~15g / m 2 .

4. The method for preparing composite thermoformed tableware according to claim 1, characterized in that: The coating weight of the oil-resistant layer is 0.1 g / m². 2 ~2g / m 2 .

5. The method for preparing composite thermoformed tableware according to claim 1, characterized in that: The preparation method includes a drying step, which is performed between the composite step and the thermoforming step. The drying step dries the composite material at a temperature of 100℃ to 200℃.

6. The method for preparing composite thermoformed tableware according to claim 1, characterized in that: The composite thickness of the three-dimensional shaped billet is 100 μm to 10 mm, the load-bearing capacity of the three-dimensional shaped billet is 0.9 kgf to 2.0 kgf, and the interlayer bonding force of the three-dimensional shaped billet is greater than 120 J / m. 2 .

7. The method for preparing composite thermoformed tableware according to any one of claims 1 to 6, characterized in that: The preparation method is carried out by a laminating machine, which includes a transfer mechanism, a preheating zone, a laminating zone, and a thermoforming zone. The transfer mechanism includes at least two unwinding devices, the preheating zone includes at least two heating rollers, the laminating zone includes multiple extrusion rollers, and the thermoforming zone includes a molding device. The molding material is transferred to the preheating zone through the unwinding devices, the heating rollers heat the molding material, the extrusion rollers laminate multiple layers of the molding material, and the molding device thermoforms the laminated molding material.

8. A composite thermoformed tableware, characterized in that: The tableware is prepared by the preparation method according to any one of claims 1 to 7; The tableware comprises at least two layers of molding material, which are stacked to form a composite structure. The molding material includes one or more of paper, plastic and inorganic materials.

9. The composite thermoformed tableware according to claim 8, characterized in that: An adhesive is provided between two adjacent layers of the molding material. The adhesive comprises, by mass fraction, 20%–50% homopolymer polyacrylate and 50%–80% silica pigment, or by mass fraction, 50%–95% PVA and 5%–50% starch; the amount of adhesive used is 3 g / m³. 2 ~15g / m 2 ; The tableware is coated with an oil-resistant layer on both its inner and outer surfaces. This oil-resistant layer comprises, by mass fraction, 1%–50% starch, 50%–98% polyacrylate emulsion, and 1%–3% alkyl ketene dimer emulsion. The coating amount of this oil-resistant layer is 0.1 g / m². 2 ~2g / m 2 .

10. The composite thermoformed tableware according to claim 8 or 9, characterized in that: The tableware includes a handle and a main body, the handle and the main body are integrally formed and connected, and an inner arc is formed at the corner between the handle and the main body.

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