阅读说明：本技术 一种应用于食品包装纸的防油抗菌涂层的制备方法 (Preparation method of oil-proof antibacterial coating applied to food packaging paper ) 是由 王利强 王飞杰 马淑凤 李江阔 张新昌 宋会民 于 2020-11-25 设计创作，主要内容包括：本发明涉及一种应用于食品包装纸的防油抗菌涂层的制备方法,属于食品包装技术领域。其将羧甲基壳聚糖和抗菌剂溶于去离子水中加热搅拌,得到羧甲基壳聚糖溶液；将羧甲基纤维素钠溶解于去离子水中抗菌搅拌,得到羧甲基纤维素钠溶液；将羧甲基壳聚糖溶液和羧甲基纤维素钠溶液按比例复配得到放油液；在放油液中加入增塑剂,分散均匀消泡后即得应用于食品包装纸的防油抗菌涂层。本发明制备所得的防油抗菌涂层可应用于食品包装纸,所得包装纸防油性能好,有较强的抑菌性能,组分均为食品级,所以安全卫生性好,还具备良好的机械性能,废弃物有较好的降解性,对环境无污染。(The invention relates to a preparation method of an oil-proof antibacterial coating applied to food packaging paper, and belongs to the technical field of food packaging. Dissolving carboxymethyl chitosan and an antibacterial agent in deionized water, heating and stirring to obtain a carboxymethyl chitosan solution; dissolving sodium carboxymethylcellulose in deionized water, and stirring for resisting bacteria to obtain sodium carboxymethylcellulose solution; compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a proportion to obtain an oil discharge liquid; and adding a plasticizer into the oil drainage solution, and dispersing uniformly and defoaming to obtain the oil-proof antibacterial coating applied to the food packaging paper. The oil-proof antibacterial coating prepared by the invention can be applied to food packaging paper, the obtained packaging paper has good oil-proof performance and stronger antibacterial performance, and the components are all food-grade, so the coating has good safety and sanitation, good mechanical performance, good degradability of wastes and no pollution to the environment.)

1. A preparation method of an oil-proof antibacterial coating applied to food packaging paper is characterized by comprising the following steps: dissolving carboxymethyl chitosan and an antibacterial agent in deionized water, heating and stirring to obtain a carboxymethyl chitosan solution; dissolving sodium carboxymethylcellulose in deionized water, and stirring for resisting bacteria to obtain sodium carboxymethylcellulose solution; compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a proportion to obtain an oil discharge liquid; and adding a plasticizer into the oil drainage solution, and dispersing uniformly and defoaming to obtain the oil-proof antibacterial coating applied to the food packaging paper.

2. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 1, wherein the carboxymethyl chitosan solution is prepared by the following steps: dissolving 1-7 g of carboxymethyl chitosan and 0.2-3 g of an antibacterial agent in 90-110 mL of deionized water, heating to 40-55 ℃, and stirring for 1-2 hours to obtain a carboxymethyl chitosan solution.

3. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 2, is characterized in that: the antibacterial agent is specifically one or a combination of several of nano zinc oxide, nano titanium oxide and nano silver.

4. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 2, is characterized in that: the addition amount of the antibacterial agent is 0.5-3 g.

5. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 2, is characterized in that: the dosage of the carboxymethyl chitosan is 2.6-7 g.

6. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 1, characterized in that the preparation process of the sodium carboxymethyl cellulose solution is as follows: dissolving 1.5-3 g of sodium carboxymethylcellulose in 90-120 g of deionized water, heating to 40-60 ℃, and stirring for 1.5-3 h to obtain a sodium carboxymethylcellulose solution.

7. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 1, which is characterized in that: compounding the obtained carboxymethyl chitosan solution and the sodium carboxymethyl cellulose solution according to the volume ratio of 1-5: 1-5 to prepare the oil discharging liquid.

8. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 1, which is characterized in that: the plasticizer is one or more of glycerol, lecithin and polyacrylic acid.

9. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 1, which is characterized in that: the addition amount of the plasticizer is 1-5% of the total mass of the oil drainage liquid; dispersing the solution uniformly by using a shaking and/or centrifuging method;

further, the oscillation frequency is 60-180 rpm/min, and the time is 30-90 min; the centrifugation speed is 3000-4500 rpm/min, and the time is 10-15 min.

10. The method for preparing the oil-proof antibacterial coating applied to the food packaging paper as claimed in claim 1, which is characterized in that: the defoaming method is centrifugation and/or ultrasonic degassing;

further, the centrifugation speed is 3000-5000 rpm/min, and the time is 5-10 min; the ultrasonic degassing time is 20-60 min.

Technical Field

The invention relates to a preparation method of an oil-proof antibacterial coating applied to food packaging paper, and belongs to the technical field of food packaging.

Background

Nowadays, the oil-containing materials are widely used in food, industrial products and pharmaceutical industries. The packaging material must therefore be selected for good grease barrier properties in addition to the necessary mechanical strength. Petroleum-based compounds are often used as oil-proof materials because of their small molecular gaps, good barrier properties, and the fact that most petroleum-based compounds are not easily miscible with grease. These synthetic high molecular polymers have wide applicability and, although they have excellent oil-repellent properties, they have poor degradation ability under natural conditions. The interest in "white staining" continues to rise and people prefer to use paper packaging materials with good degradation properties. However, since paper itself has a fine porous structure and has a high air permeability, untreated paper is easily wetted with grease. The method and the process for improving the oil-proof performance of the paper are directly related to environmental protection and human health, so the research of the oil-proof paper is widely concerned by relevant scholars.

The carboxymethyl chitosan is a water-soluble chitosan derivative, functional groups such as carboxymethyl and the like are introduced on chitosan molecules, although the secondary structure of the chitosan is destroyed, a plurality of properties of the chitosan, such as strong antibacterial property and good release effect, are retained, and the carboxymethyl chitosan is an amphoteric polyelectrolyte and the like. Carboxymethyl chitosan is a chemical compound appearing in recent years, has important significance in the aspects of medicine, chemical industry, environmental protection, health care products and packaging thereof, but has relatively high cost. Sodium carboxymethyl cellulose has strong hydrophilicity, but the viscosity of a water solution at normal temperature is large, and the viscosity of the solution can be reduced by increasing the temperature, so the sodium carboxymethyl cellulose is generally used as a thickening agent and is commonly used in the field of food. The nano titanium oxide is an antibacterial agent with good performance, and the antibacterial principle is that the nano titanium oxide decomposes bacteria under the action of photocatalysis to achieve the antibacterial effect, so that the activity of a plurality of enzymes can be inhibited, and microorganisms are killed.

Disclosure of Invention

The invention aims to overcome the defects and provides a preparation method of an oil-proof antibacterial coating applied to food packaging paper, which can enhance the oil resistance, the antibacterial property, the gas barrier property, the mechanical strength and the like of the packaging paper.

According to the technical scheme, the preparation method of the oil-proof antibacterial coating applied to the food packaging paper comprises the steps of dissolving carboxymethyl chitosan and an antibacterial agent in deionized water, heating and stirring to obtain a carboxymethyl chitosan solution; dissolving sodium carboxymethylcellulose in deionized water, and stirring for resisting bacteria to obtain sodium carboxymethylcellulose solution; compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a proportion to obtain an oil discharge liquid; and adding a plasticizer into the oil drainage solution, and dispersing uniformly and defoaming to obtain the oil-proof antibacterial coating applied to the food packaging paper.

In a preferred embodiment of the present invention, the carboxymethyl chitosan solution is prepared as follows: dissolving 1-7 g of carboxymethyl chitosan and 0.2-3 g of an antibacterial agent in 90-110 mL of deionized water, heating to 40-55 ℃, and stirring for 1-2 hours to obtain a carboxymethyl chitosan solution.

In a preferred embodiment of the invention, the antibacterial agent is specifically one or a combination of several of nano zinc oxide, nano titanium oxide and nano silver.

In a preferred embodiment of the present invention, the amount of the antibacterial agent added is 0.5 to 3 g.

In a preferred embodiment of the present invention, the amount of the carboxymethyl chitosan is 2.6 to 7 g.

In a preferred embodiment of the present invention, the preparation process of the sodium carboxymethyl cellulose solution is as follows: dissolving 1.5-3 g of sodium carboxymethylcellulose in 90-120 g of deionized water, heating to 40-60 ℃, and stirring for 1.5-3 h to obtain a sodium carboxymethylcellulose solution.

In a preferred embodiment of the invention, the obtained carboxymethyl chitosan solution and the sodium carboxymethyl cellulose solution are compounded according to the proportion of 1-5: 1-5 to prepare the oil-discharging liquid.

In a preferred embodiment of the present invention, the plasticizer is one or more selected from glycerol, lecithin, and polyacrylic acid.

In a preferred embodiment of the invention, the addition amount of the plasticizer is 1-5% of the oil discharge liquid; the solution is dispersed evenly by shaking and/or centrifuging.

In a preferred embodiment of the present invention, the oscillation frequency is 60-180 rpm/min, and the time is 30-90 min; the centrifugation speed is 3000-4500 rpm/min, and the time is 10-15 min.

As a preferred embodiment of the present invention, the defoaming method is centrifugation and/or ultrasonic degassing.

In the preferred embodiment of the invention, the centrifugation speed is 3000-5000 rpm/min, and the time is 5-10 min; the ultrasonic degassing time is 20-60 min.

Compared with the prior art, the invention has the beneficial effects that:

1. after the coating is coated on paper or paperboard, the paper food packaging material can be used for paper food packaging such as lunch boxes and the like, and compared with most of the existing lunch boxes and food packaging paper, all the materials do not contain petroleum-based compounds, so that the waste is convenient to recycle;

2. the carboxymethyl chitosan and the sodium carboxymethyl cellulose in the invention are both environment-friendly degradable materials, and the nano titanium oxide is non-toxic to human bodies and has good chemical stability. Since no fluorine-containing oil repellent is used, there is no fear that harmful substances such as perfluorooctane sulfonic acid are generated. The used materials are all food-grade, green and safe, so the materials have superior environmental protection and degradation.

3. After the coating is coated on paper or paperboard, the barrier property is improved, and the oil resistance meets the requirement of oil-proof packaging paper; the carboxymethyl chitosan and the nano titanium oxide both have good antibacterial activity, and the antibacterial performance of the coating is good.

Detailed Description

Example 1

(1) Preparation of carboxymethyl chitosan solution: weighing 3.5g of carboxymethyl chitosan in a beaker, adding 0.8g of nano titanium oxide into the beaker, adding 102mL of deionized water, heating to 42 ℃ by using a magnetic stirrer, and stirring for 70min to obtain a carboxymethyl chitosan solution;

(2) preparation of sodium carboxymethyl cellulose solution: weighing 2.2g of sodium carboxymethylcellulose in a beaker, adding 95mL of deionized water into the beaker, heating the mixture to 40 ℃ by using a magnetic stirrer, and stirring for 120min to obtain a sodium carboxymethylcellulose solution;

(3) compounding: compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a volume ratio of 4:5 to obtain a discharging oil solution; adding glycerol accounting for 2% of the total mass of the oil-containing liquid, uniformly dispersing the solution at a shaking speed of 60rpm, degassing for 5min by using a vacuum pump, and uniformly dispersing and defoaming to obtain the oil-proof antibacterial coating applied to the food packaging paper.

Example 2

(1) Preparation of carboxymethyl chitosan solution: weighing 4g of carboxymethyl chitosan in a beaker, adding 0.5g of nano zinc oxide into the beaker, adding 96mL of deionized water, heating to 40 ℃ by using a magnetic stirrer, and stirring for 70min to obtain a carboxymethyl chitosan solution;

(2) preparation of sodium carboxymethyl cellulose solution: weighing 2.5g of sodium carboxymethylcellulose in a beaker, adding 110mL of deionized water, heating to 40 ℃ by using a magnetic stirrer, and stirring for 150min to obtain a sodium carboxymethylcellulose solution;

(3) compounding: compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a volume ratio of 5:4, adding lecithin accounting for 2% of the total mass of the oil liquid, uniformly dispersing the solution at a shaking rate of 70rpm, degassing for 8min by using a vacuum pump, and uniformly dispersing and defoaming to obtain the oil-proof antibacterial coating applied to food packaging paper.

Example 3

(1) Preparation of carboxymethyl chitosan solution: weighing 4.5g of carboxymethyl chitosan in a beaker, adding 1g of nano-silver into the beaker, adding 110mL of deionized water, heating to 42 ℃ by using a magnetic stirrer, and stirring for 70min to obtain a carboxymethyl chitosan solution;

(2) preparation of sodium carboxymethyl cellulose solution: weighing 2g of sodium carboxymethylcellulose into a beaker, adding 105mL of deionized water into the beaker, heating the mixture to 40 ℃ by using a magnetic stirrer, and stirring the mixture for 110min to obtain a sodium carboxymethylcellulose solution;

(3) compounding: compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a volume ratio of 2:3, adding glycerol accounting for 3% of the total mass of the oil liquid, uniformly dispersing the solution at a vibration speed of 60rpm, degassing for 5min by using a vacuum pump, and uniformly dispersing and defoaming to obtain the oil-proof antibacterial coating applied to food packaging paper.

Example 4

(1) Preparation of carboxymethyl chitosan solution: weighing 5.5g of carboxymethyl chitosan in a beaker, adding 0.6g of nano titanium oxide into the beaker, adding 105mL of deionized water, heating to 42 ℃ by using a magnetic stirrer, and stirring for 90min to obtain a carboxymethyl chitosan solution;

(2) preparation of sodium carboxymethyl cellulose solution: weighing 2.1g of sodium carboxymethylcellulose into a beaker, adding 92mL of deionized water into the beaker, heating the mixture to 40 ℃ by using a magnetic stirrer, and stirring the mixture for 120min to obtain a sodium carboxymethylcellulose solution;

(3) compounding: compounding a carboxymethyl chitosan solution and a sodium carboxymethyl cellulose solution according to a volume ratio of 3:2, adding polyacrylic acid accounting for 2% of the total mass of the oil liquid, uniformly dispersing the solution at a vibration speed of 60rpm, degassing for 10min by using a vacuum pump, and uniformly dispersing and defoaming to obtain the oil-proof antibacterial coating applied to food packaging paper.

Application example 1

A performance test was performed on the oil-resistant and antibacterial coating applied to food wrapping paper prepared in examples 1 to 4.

1. The base paper and the coated paper are treated according to GB/T10739-2002. The paper was coated with the coating obtained in each of the above examples at a coater speed of 40mm/s and after coating, the paper was dried with an air drying oven at a drying temperature of 65 ℃.

2. Oil repellency rating Test Oil drop Test (Oil Kit Test-TAPPI T559 pm-96) was used: the test solution was dropped onto the coated paper from a height of 2.54cm, the solution was wiped off after 15 seconds, the wetting of the test solution was observed, and if there was a wetted area, the coated paper did not reach the grade represented by the test solution, and each sample was tested five times, and the average value was taken as the grease resistance value of the paper.

3. According to GB/T21510-.

The results of the performance tests of the examples are shown in table 1.

TABLE 1

	Example 1	Example 2	Example 3	Example 4
					Oil repellency rating	7	8	7	10
Antibacterial rate of Escherichia coli	26.8％	31.2％	23.3％	35.2％
					Staphylococcus aureus bacteriostasis rate	39.6％	43％	36.7％	51.2％

It can be seen from table 1 that the oil-proof level is gradually increased with the increasing content of carboxymethyl chitosan and sodium carboxymethyl cellulose, wherein the oil-proof effect is better when the proportion of carboxymethyl chitosan is more, and the oil-proof effect is reduced when the proportion of sodium carboxymethyl cellulose is increased. And the more the carboxymethyl chitosan and the antibacterial agent are added, the more the antibacterial effect is remarkable. The oil-proof and antibacterial effects of the coated paper prepared according to the parameter ratios in the embodiment 4 are better.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.