Plastic-free coating and preparation process thereof

Abstract

The invention provides a plastic-free coating and a preparation process thereof, and relates to the technical field of plastic-free coatings, the plastic-free coating comprises an acrylic acid-styrene copolymer emulsion, bagasse pulp, a diluent and an assistant, the acrylic acid-styrene copolymer emulsion is used as a coating film-forming substance, the mass fraction of the acrylic acid-styrene copolymer emulsion is 35-45%, the mass fraction of the bagasse pulp is used as a coating auxiliary film-forming substance, and the diluent is used as a diluent. The mass fraction of the flame retardant is 28-40%, the mass fraction of the diluent is 21-28%, and the mass fraction of the assistant is 2.15-3.25%; the technical key points are as follows: the plastic-free coating is prepared from an acrylic acid-styrene copolymer emulsion, bagasse pulp, a diluent and an auxiliary agent, and whether a product can be continuously used or not is judged according to the yellowing degree of a coated surface of the product by virtue of the characteristic that the fiber absorbs water and is easily yellowed when exposed in air, so that the product can be favorably used in a qualified state.

Description

Technical Field

[0001] The invention relates to the technical field of plastic-free coatings, in particular to a plastic-free coating and a preparation process thereof. Background Art

[0002] Paint is applied to the surface of the object to be protected or decorated, and can form a continuous film that is firmly attached to the coated object. It is usually a viscous liquid made of organic solvents or water, mainly based on resin, oil, or emulsion, with or without added pigments and fillers and corresponding additives.

[0003] Paints generally consist of four basic ingredients: film-forming substances (resins, emulsions), pigments (including body pigments), solvents and additives (auxiliaries). According to the main film-forming substances used in paints, paints can be divided into oil-based paints, fiber paints, synthetic paints and inorganic paints; according to the properties of paints or paint films, they can be divided into solutions, latex, sols, powders, glossy, matte and colorful art paints.

[0004] Film-forming substances are the main components of coatings, including oils, oil processing products, cellulose derivatives, natural resins, synthetic resins and synthetic emulsions. Film-forming substances also include some non-volatile active diluents, which are the main substances that make the coating firmly adhere to the surface of the coated object to form a continuous film. They are the basis of the coating and determine the basic properties of the coating.

[0005] Additives such as defoamers, leveling agents, etc., and some special functional additives such as substrate wetting agents, etc. These additives generally cannot form a film and are added in small amounts, but they play a very important role in the process and durability of the base material to form a coating.

[0006] Pigments are generally divided into two types, one is coloring pigments, such as titanium dioxide, chrome yellow, etc., and the other is body pigments, which are often called fillers, such as calcium carbonate and talcum powder.

[0007] Solvents (mineral spirits, kerosene, gasoline, benzene, toluene, xylene, etc.), alcohols, ethers, ketones and esters. The main function of solvents and water is to disperse the film-forming base material to form a viscous liquid. It helps with construction and improves certain properties of the coating.

[0008] Patent document with publication number CN116082903B discloses a plastic-free water-based heat-seal coating and a preparation device thereof. The following components by mass fraction are mixed: 25-36% acrylic styrene copolymer emulsion, 35-45% modified pure acrylic emulsion, 6-8% palm wax emulsion, 33-43% diluent and 0.52-2.15% auxiliary agent. The plastic-free water-based heat-seal coating is formed after being stirred and mixed in a stirring tank. The coating can be applied on the surface of paper food packaging materials to form a film. The product can replace PE coating as an oil-proof and anti-seepage treatment product for paper food packaging such as paper cups and paper bags, and has the advantage of good anti-seepage effect.

[0009] However, in the process of implementing the above technical solution, it is found that the above technical solution has the following technical problems:

[0010] Existing plastic-free water-based heat-seal coatings are formed as a thin film by coating the surface of paper food packaging materials. They can replace PE coating as a protective layer for paper food packaging such as paper cups and paper bags. However, acrylic emulsions must be sealed and stored indoors to prevent them from being exposed to the sun and rain. During the production process, the raw materials do not absorb water obviously, which makes it difficult to detect the water absorption of the product, ultimately affecting the product safety of the coating application. Summary of the invention

[0011] In order to overcome the shortcomings of existing plastic-free water-based heat-seal coatings that the raw materials are not easily noticeable in water absorption, which ultimately affects the safety of the products used in the coatings, the embodiments of the present application provide a plastic-free coating and a preparation process thereof. The plastic-free coating is prepared by using acrylic styrene copolymer emulsion, bagasse pulp, diluent and additives, and after sampling and testing the viscosity, hot water penetration resistance, oil penetration resistance and alcohol penetration resistance, the coating can be coated on paper to make a product. By taking advantage of the characteristic that fibers absorb water and turn yellow easily when exposed to the air, it can be judged whether the product can continue to be used according to the degree of yellowing of the coated surface of the product, which is conducive to ensuring the safety of product use.

[0012] The technical solution adopted by the embodiment of the present application to solve the technical problem is:

[0013] A plastic-free coating comprises an acrylic styrene copolymer emulsion, bagasse pulp, a diluent and an auxiliary agent, wherein the acrylic styrene copolymer emulsion is used as a coating film-forming substance, and the mass fraction thereof is 35-45%, the bagasse pulp is used as a coating auxiliary film-forming substance, and the mass fraction thereof is 28-40%, the mass fraction of the diluent is 21-28%, and the mass fraction of the auxiliary agent is 2.15-3.25%.

[0014] A preparation process of a plastic-free coating, step 1: selecting an acrylic styrene copolymer emulsion, bagasse pulp, a diluent and an auxiliary agent according to mass fractions, and separating and storing them in a corresponding required storage environment for standby use;

[0015] Step 2: stirring and mixing the acrylic styrene copolymer emulsion with a target mass fraction and a diluent including clean water to form a mixed material;

[0016] Step 3: Mix the target mass fraction of bagasse pulp into the mixed material and stir evenly to make the coating gradually become viscous and make the raw materials evenly mixed;

[0017] Step 4: Add additives gradually during the stirring and mixing process to adjust the consistency of the mixed material to achieve the target viscosity, pH value and color, and finally obtain the terminal material;

[0018] Step 5: Put the terminal material into a sealed tank, take samples from it, and store them in different sample dishes;

[0019] Step 6: In different sample dishes, the samples are tested for viscosity, resistance to hot water penetration, resistance to oil penetration, and resistance to alcohol penetration;

[0020] Step 7: According to the qualified situation of sample testing, the terminal material is packaged in a sealed can and waits for the subsequent coating work of the product.

[0021] In a possible implementation, in step 6, when testing the viscosity of the terminal material, an air knife is used to coat the paper twice on one side, and the coating amount each time is 2.5 g / m 2 .

[0022] In a possible implementation, in step 6, a sealing machine is used to seal the paper with the coating on the surface at 50 to 300 O Fold down in C and stick with 10mm width.

[0023] In a possible implementation, the method for testing the hot water penetration resistance after single-sided coating in step seven is to fold the coated paper into a small box without a lid, with the coated surface facing inward, add freshly boiled hot water, let it stand for 20 minutes, and observe whether there is water seepage.

[0024] In a possible implementation, the method for testing the oil penetration resistance after single-sided coating in step seven is to fold the coated paper into a small box without a lid, with the coated surface facing inward, add squeezed and cooled edible oil, and place it in a dry environment for 12 hours to observe whether there is oil seepage.

[0025] In a possible implementation, the alcohol permeability resistance test after single-sided coating in step seven is to dissolve methyl orange in alcohol to prepare a colored alcohol solution, apply it on the coated surface of the paper with a glass rod, and observe whether it penetrates.

[0026] In one possible implementation, the temperature of the sealing machine is adjusted to a suitable temperature, the coated paper is placed on top of the uncoated paper, and the two are quickly pressed together after alignment. The heat sealability is tested by tearing open the seal and observing the shedding of paper fibers at the seal.

[0027] The beneficial effects of this application are:

[0028] In this scheme, a plastic-free coating is prepared by using acrylic styrene copolymer emulsion, bagasse pulp, diluent and additives, and after sampling and testing the viscosity, hot water penetration resistance, oil penetration resistance and alcohol penetration resistance, it can be coated on paper to make a product. By taking advantage of the property that fibers absorb water and turn yellow easily when exposed to air, it can be judged whether the product can continue to be used according to the yellowing degree of the coated surface of the product, which is conducive to ensuring the safety of product use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a schematic diagram of the preparation process of a plastic-free coating. DETAILED DESCRIPTION

[0030] The technical solution in the embodiment of the present application is to solve the problems of the above-mentioned background technology, and the overall idea is as follows:

[0031] Example:

[0032] This embodiment introduces a plastic-free coating, including acrylic styrene copolymer emulsion, bagasse pulp, diluent and additives, acrylic styrene copolymer emulsion (mass fraction of 35-45%) is used as a coating film-forming substance, bagasse pulp (mass fraction of 28-40%) is used as a coating auxiliary film-forming substance, diluent (mass fraction of 21-28%), additives (mass fraction of 2.15-3.25%);

[0033] Among them, referring to the components of existing plastic-free coatings, bagasse pulp is used to assist film formation. With the help of the fiber material in the bagasse pulp, when it is made into a coating and coated on paper, the fiber absorbs water and is easily yellowed when exposed to the air. When the coating is used to make a product, the storage quality is judged according to the yellowing degree of the coated surface of the product to determine whether it can continue to be used;

[0034] Specific reference Figure 1 As shown, a process for preparing a plastic-free coating comprises:

[0035] S1. Select acrylic acid styrene copolymer emulsion, bagasse pulp, diluent and auxiliary agent (each component is selected according to mass fraction), separate and reserve for standby use (and store in an environment consistent with its original storage conditions);

[0036] S2, stirring and mixing the target acrylic styrene copolymer emulsion (mass fraction of 35-45%) and a diluent comprising clean water (mass fraction of 21-28%) to form a mixed material;

[0037] S3, mixing bagasse pulp (mass fraction 28-40%) into the mixed material, stirring evenly, so that the coating gradually becomes viscous, and the raw materials are mixed evenly;

[0038] S4. During the stirring and mixing process, additives are gradually added to adjust the consistency of the mixed material to achieve the target viscosity, pH value and color, and finally obtain the terminal material;

[0039] S5. Put the terminal material into a sealed tank, take samples from it, and store them in different sample dishes, that is, take out part of the same terminal material and divide it into raw materials for different experiments, waiting for different experimental conditions to be applied. Because the combined conclusions of the experiments with the same raw materials are convincing to a certain extent;

[0040] S6. In different sample dishes, the samples are tested for viscosity, resistance to hot water penetration, resistance to oil penetration, and resistance to alcohol penetration;

[0041] When testing the above functions, the following experiments need to be performed:

[0042] Experiment 1: Use an air knife to coat one side of the paper twice, with the coating amount of 2.5g / m2 each time (to test the viscosity of the final material); O C fold down (sealing machine pasting 10mm width);

[0043] Then, adjust the temperature of the sealing machine to a suitable temperature, place the coated paper on top of the uncoated paper, and quickly press them together after alignment, and tear open the seal to observe the shedding of paper hair at the seal, so as to obtain the test results of heat sealability (each heat seal ensures that the non-coated surface of the coated paper sheet contacts the heating strip, and the coated surface contacts the uncoated base paper to be bonded);

[0044] Experiment 2: Use an air knife to coat the paper twice on one side, fold the coated paper into a small box without a cover, with the coated side facing inward, add freshly boiled hot water, and wait for 20 minutes to observe whether there is water seeping out of the small box. This can determine its resistance to hot water leakage and facilitate the confirmation of the actual application temperature environment of the coating.

[0045] Experiment 3: Use an air knife to coat one side of the paper twice, fold the coated paper into a small box without a lid, with the coated side facing inward, add squeezed and cooled cooking oil (to eliminate the influence of water absorption), and place it in a dry environment for 12 hours to observe whether there is oil seepage, which can determine its oil leakage resistance;

[0046] Experiment 4: Use an air knife to coat the paper twice on one side, and use methyl orange dissolved in alcohol to prepare a colored alcohol solution, and use a glass rod to scrape it on the coated surface of the paper to observe whether it penetrates, which can test the coating's resistance to alcohol penetration;

[0047] S7. According to the qualified status of the sample test, the terminal material is packaged in a sealed can and waits for the subsequent coating work of the product.

[0048] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A plastic-free coating, characterized in that: include: Acrylic styrene copolymer emulsion, bagasse pulp, diluents and additives; Among them, the acrylic styrene copolymer emulsion is used as a coating film-forming substance with a mass fraction of 35-45%, the bagasse pulp is used as a coating auxiliary film-forming substance with a mass fraction of 28-40%, the diluent has a mass fraction of 21-28%, and the auxiliary agent has a mass fraction of 2.15-3.25%.

2. A process for preparing a plastic-free coating, which is used to prepare a plastic-free coating according to claim 1, characterized in that: include: Step 1: Select acrylic styrene copolymer emulsion, bagasse pulp, diluent and additive according to mass fraction, separate and reserve them in corresponding required storage environment; Step 2: stirring and mixing the acrylic styrene copolymer emulsion with a target mass fraction and a diluent including clean water to form a mixed material; Step 3: Mix the target mass fraction of bagasse pulp into the mixed material and stir evenly to make the coating gradually become viscous and make the raw materials evenly mixed; Step 4: Add additives gradually during the stirring and mixing process to adjust the consistency of the mixed material to achieve the target viscosity, pH value and color, and finally obtain the terminal material; Step 5: Put the terminal material into a sealed tank, take samples from it, and store them in different sample dishes; Step 6: In different sample dishes, the samples are tested for viscosity, resistance to hot water penetration, resistance to oil penetration, and resistance to alcohol penetration; Step 7: According to the qualified situation of sample testing, the terminal material is packaged in a sealed can and waits for the subsequent coating work of the product.

3. The process for preparing a plastic-free coating according to claim 1, characterized in that: In step 6, when testing the viscosity of the final material, the air knife is used to coat the paper twice on one side, and the coating amount each time is 2.5 g / m 2 .

4. A process for preparing a plastic-free coating as claimed in claim 3, characterized in that: In the step six, a sealing machine is used to fold the paper with the coating on the surface at 50-300° C. and paste the paper with a width of 10 mm.

5. The process for preparing a plastic-free coating according to claim 3, characterized in that: The method for testing the hot water penetration resistance after single-sided coating in step seven is to fold the coated paper into a small box without a lid, with the coated surface facing inward, add freshly boiled hot water, let it stand for 20 minutes, and observe whether there is water seepage.

6. The process for preparing a plastic-free coating according to claim 1, characterized in that: The method for testing the oil penetration resistance after single-sided coating in step seven is to fold the coated paper into a small box without a lid, with the coated surface facing inward, add squeezed and cooled edible oil, and place it in a dry environment for 12 hours to observe whether there is oil seepage.

7. The process for preparing a plastic-free coating according to claim 1, characterized in that: The alcohol permeability resistance test method after single-sided coating in step seven is to dissolve methyl orange in alcohol to prepare a colored alcohol solution, apply it on the coated surface of the paper with a glass rod, and observe whether it penetrates.

8. A process for preparing a plastic-free coating as claimed in claim 4, characterized in that: Adjust the temperature of the sealing machine to a suitable temperature, place the coated paper on top of the uncoated paper, and quickly press them together after alignment. Then tear open the seal and observe the shedding of paper fibers at the seal to test the heat sealability.

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