阅读说明：本技术 一种耐用抗菌白卡纸及其制备方法 (Durable antibacterial white cardboard and preparation method thereof ) 是由 李树伟 赵奇龙 于 2018-09-11 设计创作，主要内容包括：本发明涉及耐用白卡纸加工技术领域,具体涉及一种耐用白卡纸,包括原纸和涂布层,所述涂布层包括如下重量份的原料组分：纳米碳酸钙50-80份,微晶纤维素1-5份,硅胶粉1-5份,改性淀粉25-45份,葡萄柚种子提取物0.5-2份,分散剂0.1-0.5份和消泡剂1-3份,还提供了该耐用白卡纸的制备方法；利用纯天然植物作为抗菌组分,复配得到涂布层涂布于面层与底层表面,不仅具有抗菌的作用,而且天然无公害,对人体不存在潜在的危害；该涂布层添加的改性淀粉,不仅不存在腐蚀性,提高了白卡纸的耐用性能,而且提高了涂布层与纸基的附着性。(The invention relates to the technical field of durable white cardboard processing, in particular to a durable white cardboard which comprises base paper and a coating layer, wherein the coating layer comprises the following raw material components in parts by weight: 50-80 parts of nano calcium carbonate, 1-5 parts of microcrystalline cellulose, 1-5 parts of silica gel powder, 25-45 parts of modified starch, 0.5-2 parts of grapefruit seed extract, 0.1-0.5 part of dispersing agent and 1-3 parts of defoaming agent, and also provides a preparation method of the durable white cardboard; pure natural plants are used as antibacterial components, and the coating layers are obtained by compounding and coated on the surfaces of the surface layer and the bottom layer, so that the coating has an antibacterial effect, is natural and pollution-free, and has no potential harm to human bodies; the modified starch added in the coating layer has no corrosivity, improves the durability of the white cardboard, and improves the adhesion between the coating layer and the paper base.)

1. The durable antibacterial white cardboard is characterized by comprising base paper and a coating layer, wherein the coating layer comprises the following raw material components in parts by weight: 50-80 parts of nano calcium carbonate, 1-5 parts of microcrystalline cellulose, 1-5 parts of silica gel powder, 25-45 parts of modified starch, 0.5-2 parts of grapefruit seed extract, 0.1-0.5 part of dispersing agent and 1-3 parts of defoaming agent.

2. The durable antibacterial ivory board according to claim 1, wherein: the coating layer comprises the following raw material components in parts by weight: 60-70 parts of nano calcium carbonate, 2-4 parts of microcrystalline cellulose, 2-4 parts of silica gel powder, 30-40 parts of modified starch, 1-1.5 parts of grapefruit seed extract, 0.2-0.4 part of dispersing agent and 1.5-2.5 parts of defoaming agent.

3. The durable antibacterial ivory board according to claim 1, wherein: the modified starch is obtained by treating corn starch with modified enzyme, and the mass ratio of the corn starch to the modified enzyme is (12-18): 1.

4. the durable antibacterial ivory board according to claim 3, wherein: the modified enzyme comprises the following components in parts by weight: 0.1-0.3 part of modified amylase, 0.1-0.2 part of laccase and 0.3-0.5 part of alkaline pectinase.

5. The durable antibacterial ivory board according to claim 1, wherein: the base paper comprises a surface layer, a core layer and a bottom layer; the core layer comprises the following raw material components in parts by weight: 300 parts of bleached chemithermomechanical pulp and 130 parts of bleached willow wood pulp.

6. The durable antibacterial ivory board according to claim 5, wherein the surface layer comprises the following raw material components in parts by weight: 80-90 parts of bleached hardwood pulp and 10-25 parts of bleached softwood pulp.

7. The durable antibacterial ivory board according to claim 5, wherein the bottom layer comprises the following raw material components in parts by weight: 70-80 parts of bleached hardwood pulp and 20-35 parts of bleached softwood pulp.

8. A method for preparing the durable antibacterial ivory board according to any one of claims 5 to 7, characterized in that it comprises the following steps:

(1) obtaining surface pulp, core pulp and bottom pulp by pulping and jordaning;

(2) respectively making the surface pulp, the core pulp and the bottom pulp to obtain wet paper sheets with a surface layer, a core layer and a bottom layer, and sequentially squeezing and drying the wet paper sheets to obtain base paper;

(3) uniformly coating the surface layer and the bottom layer of the base paper with the coating layer, and then sequentially performing calendaring, drying, cooling, reeling and rewinding to obtain the durable antibacterial white cardboard.

9. The method for preparing the durable antibacterial ivory board according to claim 8, wherein the method comprises the following steps: in the step (3), after drying until the moisture content of the base paper is 5.0-6.5%, cooling operation is carried out.

10. The method for preparing the durable antibacterial ivory board according to claim 8, wherein the method comprises the following steps: the coating layer is subjected to surface scraper coating, primary coating is carried out, after standing and drying, coating is carried out in a surface coating mode, and secondary coating is carried out; the first coating weight is 12-15g/m²The second coating weight is 10-12g/m²。

Technical Field

The invention relates to the technical field of white cardboard processing, in particular to a durable antibacterial white cardboard and a preparation method thereof.

Background

The white cardboard is a kind of white cardboard made of thick, solid and high-quality wood pulp, and is mainly used for packaging and decorating printing stock after being calendered or embossed. Classified according to the application, there are special papers, such as single-coated white cardboard for cigarette packaging, called cigarette card, uncoated base paper for liquid food packaging, called liquid food wrapping paper, various anti-counterfeit label papers, etc. Others are coated white cardboard used for packaging various goods, such as wine bottles, cosmetics, pharmaceuticals, health products, chocolate or dessert products, dry food, frozen or frozen food, tea, coffee, clothing, toys, paintings and calligraphy, game pieces, photographic products, etc. However, whatever the product used for printing, there is a characteristic of frequent direct contact with humans. If the paper base is not subjected to antibacterial treatment, the paper base is polluted by various bacteria and fungi in the processes of printing processing, circulation, sale, use and the like, and once a contact person touches the paper base, the paper base is easily infected, various diseases are caused, and the health of people is influenced.

The time required for the organic antibacterial material to exert the antibacterial action is shorter, namely the immediate effect is good, but the antibacterial durability is worse; the inorganic antibacterial material has poor immediate effect but better antibacterial durability. With the rapid development of science and technology, various antibacterial materials have appeared, which can be roughly classified into organic antibacterial materials and inorganic antibacterial materials. Today, green and environmental protection are the focus of attention, people are aware that a great amount of organic antibacterial materials are harmful to human bodies and the environment, and when the organic antibacterial materials are used as antibacterial agents, the organic antibacterial materials cannot be guaranteed not to harm human health, and particularly, the organic antibacterial materials are applied to products frequently contacting with human bodies and need careful research, so that the use of the organic antibacterial agents is limited.

The invention patent with the patent number of 200620113237.1 discloses an antibacterial paper with antibacterial layers coated on the upper and lower surfaces of a paper fiber layer, wherein the antibacterial layers are formed by mixing a hydroxyapatite inorganic antibacterial agent containing silver and zinc ions and a surface sizing agent; because of high oxidation activity of zinc ions, the zinc ions are easy to react with substances in the air to influence the antibacterial effect of the zinc ions, and because the hydroxyapatite is used as a carrier of silver and zinc ions, the specific gravity of the hydroxyapatite is too high and reaches 3.2g/cm³The specific gravity of the paper is increased, the printing activity of the paper base is influenced, and the subsequent processing and use are troublesome; and the inorganic antibacterial agent is coated on the surface layer of the paper base for a long time, has potential corrosivity on the paper base, has no influence in a short time, increases the corrosivity after the paper base is damped, makes the paper base mildewed and rotten, and has poor durability.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the durable antibacterial white cardboard, which uses pure natural plants as antibacterial components, is compounded to obtain a coating layer, and the coating layer is coated on the surfaces of a surface layer and a bottom layer, so that the durable antibacterial white cardboard has an antibacterial effect, is natural and pollution-free, and has no potential harm to human bodies; the modified starch added in the coating layer has no corrosivity, improves the durability of the white cardboard, and improves the adhesion between the coating layer and the paper base.

The purpose of the invention is realized by the following technical scheme:

the durable antibacterial white cardboard comprises base paper and a coating layer, wherein the coating layer comprises the following raw material components in parts by weight: 50-80 parts of nano calcium carbonate, 1-5 parts of microcrystalline cellulose, 1-5 parts of silica gel powder, 25-45 parts of modified starch, 0.5-2 parts of grapefruit seed extract, 0.1-0.5 part of dispersing agent and 1-3 parts of defoaming agent.

By adopting the technical scheme, the nano calcium carbonate has small specific gravity which is about 2.0g/cm³The proportion of paper cannot be influenced, the calcium carbonate resource is wide in distribution and large in content, the raw materials are sufficiently supplied, and the cost is reduced; the nano calcium carbonate serving as a carrier of the antibacterial component has a slow release function, so that the antibacterial effect is more durable, and the nano calcium carbonate serving as a common filler for papermaking does not have adverse effects on the performance of paper, but has a certain reinforcing effect, so that the formed antibacterial film is beneficial to improving the strength of the paper, and the paper base has better printability. Microcrystalline cellulose (MCC) has special properties of lower polymerization degree, larger specific surface area and the like, and hydrogen bonds exist among molecules of the MCC and are associated with each other when being pressed, so that the MCC has high compressibility and is used for enhancing the adhesive property of the coating layer; and the microcrystalline cellulose and the nano calcium carbonate are mutually adsorbed to form a super-strong carrier of the antibacterial component, so that the reduction of the antibacterial performance of the antibacterial component can be effectively prevented. In addition, the super-strong combination of the nano calcium carbonate and the microcrystalline cellulose has a high specific surface area, can effectively play a role in moisture absorption and moisture prevention, effectively avoids the problem that the paper base is affected with damp and mildewed, and improves the durability of the white cardboard. The Grapefruit Seed Extract, GSE, is called Grapefruit Seed Extract, is extracted from natural plant materials, belongs to plant natural products, and is not harmful to human bodyAny hazard. GSE has strong antibacterial effect, is applied to fresh-keeping and sterilization of fruits and vegetables, has good effect, and has no report of applying the GSE to an antibacterial layer of a paper layer at present. The coating layer is successfully compounded by the novel antibacterial paint, the high efficiency performance can be shown even under very diluted dosage, the compounding raw materials are simple, and the unexpected antibacterial effect is achieved. The modified starch added in the coating layer is free from corrosivity, so that the durability of the white cardboard is improved, the high-strength adhesion of the coating layer and the paper base can be ensured, and the stability and the durability of the white cardboard are further improved.

Preferably, the coating layer comprises the following raw material components in parts by weight: 60-70 parts of nano calcium carbonate, 2-4 parts of microcrystalline cellulose, 2-4 parts of silica gel powder, 30-40 parts of modified starch, 1-1.5 parts of grapefruit seed extract, 0.2-0.4 part of dispersing agent and 1.5-2.5 parts of defoaming agent.

By adopting the technical scheme, the component proportion of the coating layer is further optimized, so that the coating layer is more durable and better in antibacterial performance.

Preferably, the modified starch is obtained by treating corn starch with a modified enzyme, and the mass ratio of the corn starch to the modified enzyme is (12-18): 1.

by adopting the technical scheme, the sizing component is the modified corn starch, so that the environment-friendly corn starch adhesive is green and environment-friendly, and has no harm to the environment and human bodies. The corn starch is soft, easy to press and smooth, and the printing adaptability is good; the corn starch and the modified enzyme are treated and modified, and the proportion of the corn starch and the modified enzyme is controlled, so that the bonding strength of the modified starch is greatly improved, the bonding performance is good, and the modified starch is used for surface sizing coating of a paper base and has the advantages of no powder falling and no hair falling.

Preferably, the modified enzyme comprises the following components in parts by weight: 0.1-0.3 part of modified amylase, 0.1-0.2 part of laccase and 0.3-0.5 part of alkaline pectinase.

By adopting the technical scheme and adopting the biotechnology to modify the corn starch, the defect of great harm to the environment caused by acidic or alkaline oxidation modification in the traditional chemical method is avoided. The modified enzyme obtained by compounding changes the molecular size and the starch granule property of the corn starch on the basis of the inherent property of the natural corn starch, thereby changing the natural property of the corn starch, enhancing the bonding strength of the corn starch and being more suitable for the coating layer of the invention.

Preferably, the base paper comprises a surface layer, a core layer and a bottom layer; the core layer comprises the following raw material components in parts by weight: 300 parts of bleached chemithermomechanical pulp and 130 parts of bleached willow wood pulp.

By adopting the technical scheme, only the bleached chemithermomechanical pulp is arranged in the core layer of the traditional white cardboard, so that the thickness requirement of the core layer can be met on one hand, and the white cardboard has certain stiffness on the other hand, so that the forming effect of the finished paper is good. To achieve better bulk and stiffness, the amount of bleached chemithermomechanical pulp needs to be increased continuously. However, if the amount of the white cardboard is simply adjusted, although the thickness is increased, the stiffness cannot meet the corresponding requirement, and the continuous increase of the bulk can cause problems of folding bubbles, even delamination and the like of the cardboard, thereby affecting the printing effect of the durable white cardboard. The willow fiber has the advantages of being strong in toughness, free of warping and cracking, free of moth and the like, the bleached willow wood pulp is added, and the bleached chemithermomechanical pulp is matched, so that the bulk and stiffness are balanced, the toughness, the formability, the compression-resistant and deformation-resistant capacity and the printing effect of the white cardboard are improved, and the white cardboard is more durable.

Preferably, the surface layer comprises the following raw material components in parts by weight: 80-90 parts of bleached hardwood pulp and 10-25 parts of bleached softwood pulp.

Preferably, the bottom layer comprises the following raw material components in parts by weight: 70-80 parts of bleached hardwood pulp and 20-35 parts of bleached softwood pulp.

By adopting the technical scheme, the surface layer and the bottom layer which are high in surface smoothness, good in stability and durable are obtained.

The invention also provides a preparation method of the durable antibacterial white cardboard, which comprises the following operation steps:

(1) obtaining surface pulp, core pulp and bottom pulp by pulping and jordaning;

(2) respectively making the surface pulp, the core pulp and the bottom pulp to obtain wet paper sheets with a surface layer, a core layer and a bottom layer, and sequentially squeezing and drying the wet paper sheets to obtain base paper;

(3) uniformly coating the surface layer and the bottom layer of the base paper with the coating layer, and then sequentially performing calendaring, drying, cooling, reeling and rewinding to obtain the durable antibacterial white cardboard.

By adopting the technical scheme, the coating layer is uniformly coated on the surfaces of the surface layer and the bottom layer, so that the white cardboard has durable and antibacterial effects.

Preferably, in the step (3), the drying is performed until the moisture content of the base paper is 5.0 to 6.5%, and then the cooling operation is performed.

By adopting the technical scheme, the coating layer is ensured to be gradually and fully compounded with the paper layer into a whole along with the evaporation of water, the water content is controlled to be 5.0-6.5%, and the adhesion strength of the coating layer is ensured to be optimal while the performance of the white cardboard finished product is ensured.

Preferably, the coating layer is coated for the first time by surface scraper coating, and is coated for the second time by a surface coating method after standing and drying; the first coating weight is 12-15g/m²The second coating weight is 10-12g/m²。

By adopting the technical scheme, the coating layer can fully cover the base paper, the durability and the stability of the white cardboard are improved, and the antibacterial and bright effect of the coating layer can be exerted for a long time. The coating is carried out by times, the coating weight is gradually reduced, so that a thicker coating protective layer is formed on the base paper of the coating layer, the performance of the white cardboard is improved, and meanwhile, the support is provided for the surface coating layer. The surface coating layer is thinner than the inner coating layer, so that the requirements of the coating layer are met, excessive or too thick coating is avoided, the phenomena of powder removal and black shadow on the printed matter surface in the printing process are avoided, and the comprehensive printing performance of the white cardboard is improved.

In conclusion, the invention has the following beneficial effects:

(1) the coating layer is obtained by compounding and is coated on the surface of the surface layer and the bottom layer by using the extract of the grapefruit seed as an antibacterial component, and the coating has high-efficiency antibacterial effect under very diluted dosage, is natural and pollution-free, and has no potential harm to human bodies;

(2) the corn starch is modified by the modified enzyme obtained by compounding to obtain modified starch, which is green and environment-friendly and has no harm to human bodies and the environment; the corn starch is soft, easy to press and smooth, the printing adaptability is good, the corn starch is modified by the modified enzyme, and the proportion of the modified starch and the corn starch is controlled, so that the bonding strength of the modified starch is greatly improved, the bonding performance is good, the modified starch is used for surface sizing coating of the paper base, and the paper base has the advantages of no powder falling and no hair falling while the durability of the paper base is improved;

(3) the microcrystalline cellulose and the nano calcium carbonate are mutually adsorbed to form a super-strong carrier of the antibacterial component, so that the reduction of the antibacterial performance of the antibacterial component can be effectively prevented;

(4) the combined body formed by mutual adsorption of the microcrystalline cellulose and the nano calcium carbonate has a high specific surface area, effectively plays a role in moisture absorption and moisture prevention, avoids the problem that the paper base is affected with damp and mildewed, is coated on the surface layer of the paper base as a coating layer, and improves the durability of the white cardboard.

Detailed Description

The raw material components used in the invention are all commercial products and are not subjected to secondary processing treatment. The parts described in the following examples are parts by weight, and 1 part by weight represents 1 kg.

The preparation method of the modified starch comprises the following steps:

(1) adding 100 parts of water into 0.1 part of modified amylase, 0.1 part of laccase and 0.3 part of alkaline pectinase, and mixing to obtain an enzyme solution I; 0.3 part of modified amylase, 0.2 part of laccase and 0.5 part of alkaline pectinase, and 100 parts of water are added and mixed to obtain an enzyme solution II; 0.2 part of modified amylase, 0.2 part of laccase and 0.4 part of alkaline pectinase, 100 parts of water is added, and enzyme solution III is obtained by mixing;

(2) adding water into corn starch, and stirring to prepare a corn starch suspension with the mass fraction of 30%;

(3) keeping the constant temperature at 36 ℃, and mixing an enzyme solution I according to the weight ratio of corn starch to modified enzyme of 12: 1, dripping the mixture into a corn starch suspension, uniformly stirring, heating to 80 ℃ at constant temperature, keeping stirring for 5min, performing microwave radiation treatment for 10min, rinsing with clear water, and drying at 80 ℃ to obtain modified starch I;

repeating the operation in the step (3), and mixing the enzyme solution II according to the weight ratio of the corn starch to the modified enzyme of 18: 1 is dripped into the corn starch suspension liquid according to the proportion of 1, and modified starch II is obtained after each operation treatment;

repeating the operation in the step (3), and mixing the enzyme solution III according to the weight ratio of the corn starch to the modified enzyme of 15: 1 is dripped into the corn starch suspension liquid, and modified starch III is obtained after each operation treatment;

repeating the operation in the step (3), and mixing the enzyme solution III according to the weight ratio of the corn starch to the modified enzyme of 16: the modified starch IV is obtained by dropping the starch IV into the corn starch suspension according to the proportion of 1 and carrying out various operation treatments.