阅读说明：本技术 一种隔热的纸质容器套及其制作方法 (Heat-insulating paper container sleeve and manufacturing method thereof ) 是由 曹继刚 于 2021-10-25 设计创作，主要内容包括：本发明提供了一种隔热的纸质容器套,其在环形的纸基材的内侧面设置了第一涂料层,且第一涂料层为水性可发泡涂料层；本发明的纸质容器套制造工艺简单,容易实现工业化规模生产；更为重要的是,本发明的技术方案很好地解决了现有技术中“采用具有良好的隔热保温性能的发泡层”和“较小的运输体积”无法两全的技术难题,发明人想到了采用“热膨胀微球发泡剂”开发合适的水性可发泡涂料,将其涂布于纸基材的内侧面并干燥形成涂料层；此时,纸质容器套的整体体积较小,便于运输,大幅降低纸质容器套的运输成本；之后在具体使用场景中再将该涂料层现场进行发泡处理,获得具有优良的隔热保温性能的纸质容器套,可以作为隔热外包装套,广泛应用于热饮热食、冷饮冷食的容器。(The invention provides a heat-insulating paper container sleeve, wherein a first coating layer is arranged on the inner side surface of an annular paper substrate, and the first coating layer is a water-based foamable coating layer; the paper container sleeve has simple manufacturing process and is easy to realize industrial scale production; more importantly, the technical scheme of the invention well solves the technical problems that the adoption of a foaming layer with good heat insulation and preservation performance and the adoption of a smaller transportation volume in the prior art cannot be both completed, and the inventor thinks that the adoption of a thermal expansion microsphere foaming agent develops a proper aqueous foamable coating, and the proper aqueous foamable coating is coated on the inner side surface of a paper substrate and is dried to form a coating layer; at the moment, the whole volume of the paper container sleeve is small, so that the paper container sleeve is convenient to transport, and the transportation cost of the paper container sleeve is greatly reduced; and then, in a specific use scene, the coating layer is foamed on site to obtain a paper container sleeve with excellent heat insulation performance, and the paper container sleeve can be used as a heat insulation outer packaging sleeve and widely applied to containers for hot drinks, hot foods, cold drinks and cold foods.)

1. A paper container sleeve is characterized in that:

the paper container sleeve is of a multi-layer composite structure and comprises an annular paper substrate and a first coating layer coated on the inner side surface of the paper substrate;

the paper base material is made of cellulose paper material, and the gram weight of the cellulose paper base material falls in the range of 60-300 g/m²Within the range of (1);

the first coating layer is formed by coating and drying a water-based foamable coating; the coating dry weight of the aqueous foamable coating is 10-30 g/m²；

The aqueous foamable coating comprises the following components in parts by weight:

15-30 wt% of starch base material

30-45 wt% of plant fiber slurry

3-6 wt% of light calcium carbonate

3-10 wt% of thermal expansion microsphere foaming agent

19-45 wt% of water;

the solid content of the plant fiber slurry is 35% -70%, and the ratio of the weight of the starch base material to the solid content of the plant fiber slurry is 1.2: 1-1: 1.

2. The paper container sleeve as defined in claim 1, wherein:

the starch base material is any one or a combination of any more of native starch, oxidized starch, pregelatinized starch, carboxymethyl modified starch, esterified starch and cross-linked starch.

3. The paper container sleeve as defined in claim 2, wherein:

the native starch is any one or a combination of any more of potato native starch, corn native starch, cassava native starch, sorghum native starch, mung bean native starch, wheat native starch or rice native starch;

the oxidized starch is any one or a composition of any more of cassava oxidized starch, potato oxidized starch, corn oxidized starch, wheat oxidized starch or rice oxidized starch;

the esterified starch is any one or a composition of any more of cassava esterified starch, potato esterified starch, corn esterified starch, wheat esterified starch or rice esterified starch;

the pregelatinized starch is any one or a composition of any more of cassava pregelatinized starch, potato pregelatinized starch, corn pregelatinized starch, wheat pregelatinized starch or rice pregelatinized starch;

the carboxymethyl modified starch is any one or a combination of any more of cassava carboxymethyl modified starch, potato carboxymethyl modified starch, corn carboxymethyl modified starch, wheat carboxymethyl modified starch or rice carboxymethyl modified starch;

the cross-linked starch is any one or a combination of any more of cassava cross-linked starch, potato cross-linked starch, corn cross-linked starch, wheat cross-linked starch or rice cross-linked starch.

4. The paper container sleeve as defined in claim 1, wherein:

the plant fiber pulp is paper fiber pulp; alternatively, the first and second electrodes may be,

the plant fiber pulp is a composition of paper fiber pulp and 40-100 meshes of bamboo powder and/or coffee powder.

5. The paper container sleeve as defined in claim 4, wherein:

the starch base material is cassava pregelatinized starch or cassava carboxymethyl modified starch.

6. The paper container sleeve as defined in claim 1, wherein:

the water-based foamable coating further comprises 1-2 wt% of an auxiliary agent, wherein the auxiliary agent is any one or a combination of a plurality of preservatives, flatting agents or defoaming agents.

7. The paper sleeve of any of claims 1-6 wherein:

a second coating layer is arranged on the outer side surface of the paper substrate; the second coating layer is formed by coating and drying the water-based foamable coating; the coating dry weight of the aqueous foamable coating is 10-30 g/m²。

8. A foamed paper container sleeve, characterized in that:

the paper container sleeve as claimed in any one of claims 1 to 6, wherein the first coating layer is redissolved by adding water, foamed at a temperature of 80-130 ℃, dried, cured and molded to obtain the foamed paper container sleeve.

9. A foamed paper container sleeve, characterized in that:

the paper container sleeve as claimed in claim 7, wherein the first coating layer and the second coating layer are redissolved by adding water, foamed at a temperature of 80-130 ℃, dried, cured and molded to obtain the foamed paper container sleeve.

10. The method of making a paper sleeve for containers of claim 1,

the manufacturing method comprises the following steps of:

step 1): selecting the gram weight of 60-300 g/m²A sheet of cellulosic paper material within the range of (a);

step 2): for the selected sheet, avoiding a preset edge pasting part, and coating the rest part of the sheet with the water-based foamable coating in a full-page manner, wherein the coating dry weight is 10-30 g/m²(ii) a Drying at a temperature of 60-75 ℃ to form the first coating layer;

step 3): die cutting the sheet obtained in the step 2), coating edge pasting glue on the edge pasting part, and performing an edge pasting process to obtain the paper container sleeve.

Technical Field

The invention relates to a heat-insulating paper container sleeve and a manufacturing method thereof, belonging to the technical field of packaging materials.

Background

At present, containers such as cups or buckets for containing hot beverages (such as hot coffee, hot tea, hot soybean milk, hot soup and the like) or hot foods are uncomfortable and even scalded because the high-temperature fluid contained in the containers is higher than the high-temperature state for a period of time, and the heat can be quickly transmitted to the holding surface through the cup body and the bucket body and then transmitted to the palm of a consumer.

Similarly, the outer high temperature of the container such as a cup or a barrel for containing cold drink food is conducted to the inner part through the wall of the cup or the wall of the barrel, and the cold drink in the container becomes hot, so that the taste of the cold drink food is reduced; in addition, the cold drink cup is held by hands for a long time, and the hands feel uncomfortable as cold.

Therefore, for containers for holding hot or cold beverages, corrugated paper cup sleeves are generally provided, and most commonly coffee cup sleeves are used for isolating the heat conduction between the surface of a high-temperature paper cup and the palm surface of a customer's hand so that the customer does not feel hot. However, the existing paper cup corrugated sleeve in the market adopts a structure of a hollow corrugated pipe, so that the heat preservation effect is limited.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides, in one aspect, a paper sleeve for a container, wherein,

the paper container sleeve is of a multi-layer composite structure and comprises an annular paper substrate and a first coating layer coated on the inner side surface of the paper substrate;

the paper base material is made of cellulose paper material, and the gram weight of the cellulose paper base material falls in the range of 60-300 g/m²Within the range of (1);

the first isThe coating layer is formed by coating and drying a water-based foamable coating; the coating dry weight of the aqueous foamable coating is 10-30 g/m²；

The aqueous foamable coating comprises the following components in parts by weight:

15-30 wt% of starch base material

30-45 wt% of plant fiber slurry

3-6 wt% of light calcium carbonate

3-10 wt% of thermal expansion microsphere foaming agent

19-45 wt% of water;

the solid content of the plant fiber slurry is 35% -70%, and the ratio of the weight of the starch base material to the solid content of the plant fiber slurry is 1.2: 1-1: 1.

Preferably, the starch base material is any one or a combination of any more of native starch, oxidized starch, pregelatinized starch, carboxymethyl modified starch, esterified starch and cross-linked starch.

Preferably, the native starch is any one or a combination of any more of potato native starch, corn native starch, cassava native starch, sorghum native starch, mung bean native starch, wheat native starch or rice native starch;

the oxidized starch is any one or a composition of any more of cassava oxidized starch, potato oxidized starch, corn oxidized starch, wheat oxidized starch or rice oxidized starch;

the esterified starch is any one or a composition of any more of cassava esterified starch, potato esterified starch, corn esterified starch, wheat esterified starch or rice esterified starch;

the pregelatinized starch is any one or a composition of any more of cassava pregelatinized starch, potato pregelatinized starch, corn pregelatinized starch, wheat pregelatinized starch or rice pregelatinized starch;

the carboxymethyl modified starch is any one or a combination of any more of cassava carboxymethyl modified starch, potato carboxymethyl modified starch, corn carboxymethyl modified starch, wheat carboxymethyl modified starch or rice carboxymethyl modified starch;

the cross-linked starch is any one or a combination of any more of cassava cross-linked starch, potato cross-linked starch, corn cross-linked starch, wheat cross-linked starch or rice cross-linked starch.

Preferably, the plant fiber pulp is paper fiber pulp; alternatively, the first and second electrodes may be,

the plant fiber pulp is a composition of paper fiber pulp and 40-100 meshes of bamboo powder and/or coffee powder.

Preferably, the starch base material is cassava pregelatinized starch or cassava carboxymethyl modified starch.

Preferably, the aqueous foamable coating further comprises 1-2 wt% of an auxiliary agent, wherein the auxiliary agent is selected from any one or a combination of a plurality of preservatives, leveling agents or defoaming agents.

Preferably, a second coating layer is arranged on the outer side surface of the paper substrate; the second coating layer is formed by coating and drying the water-based foamable coating; the coating dry weight of the aqueous foamable coating is 10-30 g/m²。

The invention further provides a foamed paper container sleeve, wherein in the paper container sleeve, the first coating layer is redissolved by adding water, foamed at the temperature of 80-130 ℃, dried, cured and molded to obtain the foamed paper container sleeve.

The invention further provides a foamed paper container sleeve, wherein in the paper container sleeve, the first coating layer and the second coating layer are redissolved by adding water, foamed at the temperature of 80-130 ℃, dried, cured and molded to obtain the foamed paper container sleeve.

In still another aspect of the present invention, there is provided the method for manufacturing the paper sleeve for a container as described above, wherein,

the manufacturing method comprises the following steps of:

step 1): selecting the gram weight of 60-300 g/m²A sheet of cellulosic paper material within the range of (a);

step 2): for selected sheets, avoidCoating the rest part of the preset edge pasting part on the water-based foamable coating in a full plate manner, wherein the coating dry weight is 10-30 g/m²(ii) a Drying at a temperature of 60-75 ℃ to form the first coating layer;

step 3): die cutting the sheet obtained in the step 2), coating edge pasting glue on the edge pasting part, and performing an edge pasting process to obtain the paper container sleeve.

The invention provides a heat-insulating paper container sleeve, wherein a first coating layer is arranged on the inner side surface of an annular paper substrate, and the first coating layer is a water-based foamable coating layer; the paper container sleeve has simple manufacturing process and is easy to realize industrial scale production; more importantly, the technical scheme of the invention well solves the technical problems that the foaming layer with good heat insulation and preservation performance and the smaller transportation volume cannot be adopted in the prior art, and the proper water-based foamable coating is developed by adopting the thermal expansion microsphere foaming agent and is coated on the inner side (or the inner side and the outer side) of the paper substrate and dried at the drying temperature to form the coating layer; at the moment, the thickness of the coating layer is small, the overall volume of the container sleeve is small, the transportation is convenient, and the transportation cost of the paper container sleeve is greatly reduced; after transportation is finished, the coating layer is redissolved by water in a specific use scene, then foaming is carried out at a foaming temperature, and drying and curing are carried out to form a foaming layer, so that the paper container sleeve with excellent heat insulation performance is obtained, can be used as a heat insulation outer packaging sleeve and is widely applied to containers for hot drinks, cold drinks and cold drinks.

Drawings

FIG. 1 is a schematic cross-sectional view of a paper sleeve of example 1 of the present invention;

FIG. 2 is a schematic cross-sectional view of a foamed paper container sleeve of example 1 of the present invention;

FIG. 3 is a schematic cross-sectional view of a paper sleeve of example 3 of the present invention;

fig. 4 is a schematic cross-sectional view of a foamed paper sleeve of example 3 of the present invention.

Detailed Description

In a specific embodiment of the present invention, a paper container sleeve is provided, wherein the paper container sleeve has a multi-layer composite structure comprising an annular paper substrate and a first coating layer coated on the inner side of the paper substrate;

the paper base material is made of cellulose paper material, and the gram weight of the cellulose paper base material falls in the range of 60-300 g/m²Within the range of (1);

the first coating layer is formed by coating and drying a water-based foamable coating; the coating dry weight of the aqueous foamable coating is 10-30 g/m²；

The aqueous foamable coating comprises the following components in parts by weight:

15-30 wt% of starch base material

30-45 wt% of plant fiber slurry

3-6 wt% of light calcium carbonate

3-10 wt% of thermal expansion microsphere foaming agent

19-45 wt% of water;

the solid content of the plant fiber slurry is 35% -70%, and the ratio of the weight of the starch base material to the solid content of the plant fiber slurry is 1.2: 1-1: 1.

As explained in the background of the invention, the conventional corrugated container jackets made of hollow materials have a limited thermal insulation effect, and thus, the inventors of the present application have desired to develop a paper container jacket having thermal insulation performance.

The inventors contemplate the use of foamed materials to achieve thermal insulation and preservation properties. The prior art foaming material manufacturing method generally mixes specially modified starch and chemical foaming agent (capable of generating gas such as carbon dioxide) and then produces thermoplastic starch-based foaming buffer material by a twin-screw extrusion foaming device; or the specially modified starch is reacted with a specific chemical substance under the condition of heating to generate gas, crosslink and the like to obtain the foaming buffer material; or injecting supercritical carbon dioxide gas into the thermoplastic paste, using a quick pressure relief valve to relieve pressure to obtain micro-foaming paste, co-extruding the paper paste and the micro-foaming paste to obtain a packaging paper prototype, and heating the packaging paper prototype through a heating roller to micro-foam the micro-foaming paste so as to obtain the packaging material with the foaming layer.

However, the existing methods use chemical foaming agents, plasticizers and the like, and still have adverse effects on the environment; more importantly, the methods are all used for directly manufacturing the container sleeve containing the foaming layer; the volumetrically expanded "foam layer" increases the overall volume of the container sleeve, which increases shipping costs.

Therefore, it is an unbounded technical problem for those skilled in the art to have "good thermal insulation performance" and "small transportation volume". If "good thermal insulation and cushioning properties" are obtained by the "foam layer", the volume of the "foam layer" increases shipping costs.

Based on this background, the inventor originally thought of producing a container sleeve with a small volume and no foaming, and obtaining a container sleeve with a heat insulation function after foaming by a user through simple operation after transportation.

Specifically, the inventors have contemplated developing a suitable aqueous foamable coating using a "thermally expandable microsphere foaming agent" which is applied to the inside (or inside and outside) of a paper substrate and dried at a drying temperature to form a coating layer; at the moment, the thickness of the coating layer is small, the overall volume of the container sleeve is small, the transportation is convenient, and the transportation cost of the paper container sleeve is greatly reduced; after transportation is finished, the coating layer is redissolved by water, then foaming and drying and curing are carried out at a foaming temperature to form a foaming layer, and the foamed paper container sleeve can be sleeved on the outer wall surface of a container with a corresponding size, so that the effects of heat insulation and heat preservation can be achieved.

The thermal expansion microsphere foaming agent is milky micro spherical plastic particles, the particles have a core-shell structure, the shell is a thermoplastic acrylic polymer, and the core is alkane gas; when heated to a certain temperature, the thermoplastic shell softens, the gas in the shell expands, and the hydrocarbon in the shell expands 20-50 times of the original volume in a short time; the foamed microsphere shell cannot be broken, and still keeps a complete sealed sphere, so that the foaming effect is achieved, and the foamed microsphere has good resilience and buffering performance; in addition, the polymer microsphere is non-toxic and pollution-free, and is a good environment-friendly foaming agent.

However, the "thermally expandable microsphere foaming agent" is a material that is in the form of a nearly powdery material, and in which way it can be combined with other materials to develop a suitable aqueous foamable coating, is a technical problem that the inventors need to further solve.

The inventor conducts a large amount of experiments to screen a biomass material suitable for being combined with a thermal expansion microsphere foaming agent, wherein a certain amount of light calcium carbonate is added to prepare a suitable aqueous foamable paint formula; then, the inventor selects a specific paper base material, and debugs aqueous foamable coating and coating parameters of various formulas based on the paper base material, so that the paper container sleeve product is finally obtained, is convenient to transport, and can be foamed subsequently to form the paper container sleeve with excellent heat insulation performance.

The term "light calcium carbonate", also known as precipitated calcium carbonate, has the chemical formula CaCO₃It is made by chemical processing method; the precipitated volume (2.4-2.8 mL/g) of the calcium carbonate is larger than that (1.1-1.9 mL/g) of the heavy calcium carbonate produced by a mechanical method, so the calcium carbonate is called light calcium carbonate.

The present invention will be further described with reference to the following examples, but the present invention is not limited to these specific embodiments.

And (4) supplementary notes: the percentages (%) appearing in the specific embodiments are, unless otherwise indicated, percentages by weight (% wt).

Example 1

As shown in fig. 1, a schematic cross-sectional view of a paper sleeve of example 1 of the present invention.

The paper container sleeve 1 of embodiment 1 of the present invention has a multi-layer composite structure including an annular paper substrate 10 and a first coating layer 20 coated on the inner side of the paper substrate 10.

In one embodiment of the invention, the paper substrate 10 is made of cellulose paper material and has a grammage of 60-300 g/m²Within the range of (1);

in an inventive toolIn one embodiment, the first coating layer 20 is formed by coating and drying an aqueous foamable coating; the coating dry weight of the water-based foamable coating is 10-30 g/m²；

In one particular embodiment herein, the aqueous foamable coating comprises the following components in parts by weight:

15-30 wt% of starch base material

30-45 wt% of plant fiber slurry

3-6 wt% of light calcium carbonate

3-10 wt% of thermal expansion microsphere foaming agent

19-45 wt% of water;

the solid content of the plant fiber slurry is 35% -70%, and the ratio of the weight of the starch base material to the solid content of the plant fiber slurry is 1.2: 1-1: 1.

Specifically, in this embodiment, the aqueous foamable coating material comprises the following components in parts by weight:

20% wt of starch base material (cassava pregelatinized starch)

Paper fiber pulp with 50% solid content 40% wt

Light calcium carbonate 3% by weight

9% wt of thermal expansion microsphere foaming agent

Deionized water 27% wt

1% by weight of a preservative;

in the formulation of this example, the starch base (tapioca pregelatinized starch) was a model DPT-OS-01 product from Rundy starch, Inc. of Texas; the paper fiber pulp with the solid content of 50 percent can be selected from paper fiber pulp prepared by recycling waste paper; precipitated calcium carbonate was purchased from denafil sevoro trade ltd; the thermal expansion microsphere foaming agent is purchased from Shanghai Zhimo new materials Co., Ltd; the preservative is a product of U-W66 model of new materials Co.

In this example, the weight ratio of starch base to the solids content of the vegetable fibre slurry was about 1: 1.

The specific preparation of the water-based foamable coating comprises the following steps: the components are weighed according to the formula, then poured into a paint stirring container, and stirred uniformly at the speed of about 20rpm to obtain the water-based foamable paint.

In a specific embodiment of the present application, the method for manufacturing the paper sleeve comprises the following steps in sequence:

step 1): selecting the gram weight of 60-300 g/m²A sheet of cellulosic paper material within the range of (a);

step 2): for the selected sheet, avoiding the preset edge pasting part, and coating the rest part of the sheet with the water-based foamable coating in a full-page manner, wherein the coating dry weight is 10-30 g/m²(ii) a Drying at a temperature of 60-75 ℃ to form the first coating layer 20;

step 3): die cutting the sheet obtained in the step 2), coating edge pasting glue on the edge pasting part, and performing an edge pasting process to obtain the paper container sleeve.

Specifically, in the present example, in step 1) of the above-mentioned production method, the cellulose paper material was used in a grammage of about 80g/m, which is available from paper making Co., Ltd, Japan²The natural color kraft paper.

Specifically, in this example, in step 2) of the above-mentioned production method, the coating dry weight of the aqueous foamable coating material was about 15g/m²And the coating speed is 50m/min, and a heating oven device is adopted to dry at 65 ℃ to form the first coating layer 20.

In the step 3) of the manufacturing method, the paper container sleeve 1 is die-cut into single semi-finished products by a die-cutting machine according to the shape and the size of the pre-designed paper container sleeve. Generally, the size of the monolithic semi-finished product is matched with the target container, for example, the height of the monolithic semi-finished product is 0.8 times of the height of the target container, and the arc side length of the monolithic semi-finished product is 1.2 times of the full-width circumference of the corresponding position of the outer peripheral surface of the target container.

And finally, placing the obtained single semi-finished product on a linear box pasting machine, coating edge pasting glue on the edge pasting part, folding edges and adhering and forming the edges to obtain the heat-insulating paper container sleeve shown in the figure 1.

In one embodiment of the present application, in the step 3) of the above-mentioned manufacturing method, the coating dry weight of the edge-pasting glue can be about 2-3 g/m²(ii) a The speed of the edge folding box pasting can be 40-250 m/min.

The manufacturing process of the paper container sleeve 1 of embodiment 1 of the application is simple, industrial scale production is easily realized, more importantly, the whole thickness and the whole volume of the paper container sleeve can be very small, the paper container sleeve can only be 1/5-1/3 of corrugated paper sleeves with the same application specifications on the market, the boxing transportation space can be saved, and the transportation cost of the paper container sleeve 1 is greatly reduced.

In a specific use scenario, the paper container sleeve 1 of embodiment 1 of the application is: before the paper container sleeve 1 of the embodiment 1 is sleeved on a container (for example, before a sleeve cup/a sleeve barrel), a certain amount of water is applied to the first coating layer 20 on the inner side surface of the paper container sleeve, so that the first coating layer 20 is redissolved, and then at a foaming temperature of 80-130 ℃, the first coating layer is foamed and dried and cured to form a foaming layer 20' (for example, the foaming layer 20 is placed in an oven or other heating devices with the temperature of 110 ℃ for 3 minutes for foaming and drying and curing molding), and a foamed paper container sleeve is obtained, and is shown in fig. 2. The foamed paper container sleeve can be sleeved on the outer wall surface of a container with a corresponding size, has the function of heat insulation, and can be widely applied to containers for hot drinks, hot foods, cold drinks and cold foods.

Example 2

The structure of the insulated paper container sleeve of example 2 of the present invention was the same as that of example 1.

The insulated paper container sleeve of example 2 of the present invention differs from example 1 only in that: the first coating layer 20 is prepared from different aqueous foamable coating formulations.

Specifically, in this embodiment, the aqueous foamable coating material comprises the following components in parts by weight:

25% by weight of starch base (cassava carboxymethyl modified starch)

Paper fiber pulp with 60% solid content of 27% wt

5% by weight of bamboo powder (60 meshes)

Light calcium carbonate 5 wt%

6 wt% of thermal expansion microsphere foaming agent

Deionized water 31% wt

1% by weight of a preservative;

in the formulation of this example, the starch base (tapioca carboxymethyl modified starch) was a product available from MB-CMS2 model No. from meba biotechnology limited, jing; the paper fiber pulp with the solid content of 60 percent can be selected from paper fiber pulp prepared by recycling waste paper; precipitated calcium carbonate was purchased from denafil sevoro trade ltd; the thermal expansion microsphere foaming agent is purchased from Shanghai Zhimo new materials Co., Ltd; the preservative is a product of U-W66 model of new materials Co.

In this example, the weight ratio of starch base to the solids content of the vegetable fiber slurry was about 1.179: 1.

Example 3

As shown in fig. 3, a schematic cross-sectional view of a paper sleeve of example 3 of the present invention.

The only difference between the insulated paper container sleeve of example 3 of the present invention and example 1 is that: 1) the outer side surface of the annular paper substrate 10 is also provided with a second coating layer 30.

The second dope layer 30 also adopts the water-based foamable paint, which has the same selection as the water-based foamable paint adopted in the first dope layer 20 in the above example 1, and detailed description thereof is omitted.

The manufacturing process of the heat-insulating paper container sleeve of embodiment 3 of the present invention differs from that of embodiment 1 only in that: a water-based foamable coating layer is applied to the outer surface of the paper substrate 10 (except for a predetermined paste portion). The other contents of the manufacturing process are the same as those of the manufacturing process of embodiment 1, and detailed description is omitted.

In a specific use scenario, the paper container sleeve 1 of embodiment 3 of the application is: before the paper container sleeve 1 of the embodiment 3 is sleeved on a container (for example, before a cup/barrel sleeve is sleeved), a certain amount of water is applied to the first paint layer 20 and the second paint layer 30 on the inner side and the outer side of the container to redissolve the two layers of the paint layers, and then the paint layers are foamed, dried and cured at a foaming temperature of 80-130 ℃ to form an inner foamed layer and an outer foamed layer (for example, the paint layers are placed into an oven at a temperature of 110 ℃ to be heated for 3 minutes to be foamed, dried and cured and molded), so that the foamed paper container sleeve is obtained, and the foamed paper container sleeve is shown in fig. 4.

Effect data

Comparative example 1

Comparative example 1 differs from example 1 only in that: in the formula of the water-based foamable coating, the proportion of starch base stock to plant fiber slurry (solid content) is different; specifically, the starch base is 30% by weight, and the paper fiber slurry (solid content is 50%) is 30% by weight (total amount of the two is 60% by weight), wherein the starch base: the ratio of the solids content of the vegetable fibre pulp is about 2: 1.

other characteristics and preparation methods of the paper container sleeve of the comparison document 1 are the same as those of the embodiment 1, and detailed description is omitted.

Comparative example 2

Comparative example 2 differs from example 2 only in that: in the formula of the water-based foamable coating, the proportion of starch base stock to plant fiber slurry (solid content) is different; specifically, the starch base is 30 wt%, the paper fiber slurry (solid content is 60%) is 23 wt%, and the bamboo powder is 5 wt% (total amount of the three is 58 wt%), wherein the starch base: the ratio of the solids content of the vegetable fiber slurry was about 1.596: 1.

other characteristics and preparation methods of the paper container sleeve of the comparison document 2 are the same as those of the embodiment 2, and detailed description is omitted.

The method comprises the steps of manufacturing a commercially available hollow corrugated cup sleeve, the above examples 1-3 and comparative examples 1 and 2 into cup sleeves with the same size (and performing foaming treatment on the examples 1-3 and the comparative examples 1 and 2), taking 5 disposable paper cups with the same specification and size in an indoor environment at about 25 ℃, sleeving the corresponding size paper cups in the examples 1-3 and the comparative examples 1 and 2 and the commercially available hollow corrugated cup sleeves, adding a certain amount (about 0.80cm away from the cup mouth) of hot water into the paper cup, detecting the water temperature in the paper cup by using a thermometer, sleeving the examples 1-3 and the comparative examples 1 and 2 when the water temperature is reduced to 87.8 ℃, starting timing the commercially available hollow corrugated cup sleeves, recording the change conditions of the water temperature of the inner wall of the paper cup and the surface temperature of the cup sleeves along with time, wherein the water temperature in the paper cup is measured by using the thermometer at a fixed position below the suspension liquid level, the surface temperature test of the cup sleeves adopts an infrared temperature measuring gun with the model of AZ888, the test position is the fixed position of the outer surface of the cup sleeve, and the temperature data is recorded through reading.

The results of the tests are shown in the following table 1:

TABLE 1

As can be seen from the comparison of the results in table 1, the cup sleeves of examples 1 to 3 have a slower cooling rate of the water temperature in the cup (better heat-insulating effect), and a slower heating rate of the outer wall of the cup sleeve (better heat-insulating effect), and even at the time point of 60 minutes, the water temperature in the cup can be maintained at a temperature of 60 ℃ or higher, and particularly, the outer wall of the cup sleeve can be maintained at a temperature of 35 ℃ or lower, so that the cup sleeve does not give a feeling of burning hands.

In particular, the sleeve of example 3 has a foam layer on both sides, and thus has better heat preservation and insulation effects than those of example 1.

In contrast, in the existing hollow corrugated cup sleeve, at the time point of 30 minutes, the temperature of the outer wall of the cup sleeve reaches above 40 ℃ (obvious hot feeling), and the temperature of water in the cup is reduced to below 60 ℃.

In addition, compared with the cup sleeves of comparative examples 1 and 2, the cup sleeves of examples 1 and 2 have better heat insulation performance, and prove that the heat insulation effect of a foaming layer formed by the aqueous foaming coating prepared by adopting specific parameters (specific proportion of starch base material to solid content of plant fiber slurry, specific weight parts of thermal expansion microsphere foaming agent and light calcium carbonate) is more excellent.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.