Production process of pattern-penetrating specialty paper

Abstract

The invention relates to a production process of a novel pattern-penetrating special paper. The production process of the novel pattern-penetrating special paper adopts a penetrating coating to print a pattern so that the pattern can penetrate into base paper during the printing process, and then the surface of the back of the base paper is bleached to bleach the toner molecules distributed on the back surface of the base paper, remove the pattern on the back surface of the base paper, and retain the pattern that penetrates into the base paper to obtain the novel pattern-penetrating special paper. The whole process is simple, uses less raw materials and is easy to obtain, has low process cost, has good production stability, and is conducive to large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of paper production, and in particular to a production process of a novel pattern-permeable special paper. Background Art

[0002] Printing patterns on the surface of paper, the traditional process is to print the pattern directly on the surface of paper. At present, a new type of pattern-penetrating paper has appeared on the market. This type of paper can see the printed pattern from the back of the paper, but the printed pattern exists in the interlayer of the paper. At present, the production process of this type of paper is to print the pattern in the interlayer of the paper, and then add a thin layer of pulp on the printed pattern, so as to present a special anti-counterfeiting effect that there is no printed pattern on the surface of the back of the paper, but the printed pattern in the interlayer can be seen. For example, Chinese patent document CN108360283A discloses a method for preparing sandwich pattern paper. When preparing the surface layer paper, the method for preparing the sandwich pattern paper uses a spray device to evenly spray a pulp liquid with a concentration of 3‰~5‰ on the side of the bottom paper with the sandwich pattern layer, so that the pulp covers the entire sandwich pattern layer, and the pulp is drained to obtain a moist surface layer paper. Because the production process of this paper is complicated and the production cost is high, it is not suitable for large-scale production in the printing industry, resulting in a very expensive market price for this type of paper. Summary of the invention

[0003] The problem to be solved by the present invention is to provide a production process for a new type of pattern-permeable specialty paper, which has simple production steps and low process cost, and is conducive to large-scale production. The technical solution adopted is as follows:

[0004] A production process of a novel pattern-permeable specialty paper, characterized by comprising the following steps:

[0005] Step 1: Print a pattern on the back of the base paper, and use a penetrating coating to penetrate the pattern into the base paper during printing. The penetrating coating includes a penetrant, a dispersant, a water-soluble color powder and water;

[0006] Step 2: Bleaching and drying the back surface of the infiltrated base paper to obtain the novel pattern-infiltrated specialty paper.

[0007] The base paper mentioned above is usually made of paper with good permeability, and the back side of the base paper is relatively rough to facilitate the penetration of the coating.

[0008] A pattern is printed using a penetrating coating so that the pattern can penetrate into the base paper during the printing process. Since the penetrant generally has fixed hydrophilic and lipophilic groups and can be arranged in a direction on the surface of the solution, the surface tension of the base paper can be significantly reduced under the action of the penetrant, so that the molecules of the water-soluble color powder are first evenly dissolved in water under the action of the dispersant, and then penetrate from the back surface of the base paper to the inside of the base paper under the action of the penetrant, and finally distributed from the inside of the base paper to the back surface; thereafter, the back surface of the base paper is bleached to bleach the color powder molecules distributed on the back surface of the base paper so that the base paper only retains the color of the color powder that penetrates into the inside, that is, the pattern on the back surface of the base paper is removed, and the pattern that penetrates into the inside of the base paper is retained, thereby forming the novel pattern-penetrating special paper.

[0009] As a preferred embodiment of the present invention, in step 1, when printing a pattern on the back of the base paper, the pattern is printed on the back of the base paper by a gravure printing machine, and the humidity and temperature of the base paper are kept unchanged after gravure printing. Since the base paper needs to be in full contact with the penetrant during the penetration of the pattern, the base paper after gravure printing is not dried during the gravure printing process, and the humidity and temperature of the base paper are kept unchanged to ensure the contact time between the base paper and the penetrant.

[0010] In order to ensure that the penetrant can fully penetrate the coating into the base paper, as a further preferred embodiment of the present invention, the printing speed of the gravure printing machine is 10-100 m / min.

[0011] As a further preferred embodiment of the present invention, the components of the penetration type coating include 10-30% anionic surfactant, 10-30% nonionic surfactant, 5-10% water-soluble color powder, and the rest is water. In the penetration type coating, the anionic surfactant acts as a penetrant to penetrate, and the nonionic surfactant acts as a dispersant to disperse the water-soluble color powder. 10-30% anionic surfactant and 10-30% nonionic surfactant are compounded to dissolve and disperse 5-10% water-soluble color powder, and the water-soluble color powder can penetrate into the base paper.

[0012] As a further preferred embodiment of the present invention, the anionic surfactant is at least one of α-sulfonic monocarboxylate, sodium secondary alkyl sulfonate, sodium methyl palmitate sulfonate, and sodium dodecylbenzene sulfonate.

[0013] As a further preferred embodiment of the present invention, the nonionic surfactant is at least one of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, alkylolamide, cetyl alcohol polyoxyethylene ether and lauryl alcohol polyoxyethylene ether.

[0014] As a preferred embodiment of the present invention, in step 2, when the back surface of the infiltrated base paper is bleached, the back surface of the base paper is coated with a bleaching agent through a dry coating machine, and then the bleached base paper is dried. During the coating process, the bleaching agent contacts the back surface of the base paper, and the bleaching agent undergoes an oxidation-reduction reaction with the coating molecules on the back surface of the base paper, thereby bleaching and removing the pattern on the back surface of the base paper.

[0015] As a further preferred embodiment of the present invention, in step 2, the coating speed of the dry coater is 30-60 m / min, and the drying temperature is 20-50°C.

[0016] As a further preferred embodiment of the present invention, the bleaching agent is at least one of hydrogen peroxide, sodium hypochlorite, potassium hypochlorite, potassium pyrosulfate and peracetic acid, and the mass fraction of the bleaching agent is 20-80%.

[0017] As a further preferred embodiment of the present invention, the bleaching agent is a hydrogen peroxide solution with a mass fraction of 20-60%.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The production process of the novel pattern-penetrating special paper of the present invention adopts a penetrating coating to print a pattern, so that the pattern can penetrate into the base paper during the printing process, and then the surface of the back of the base paper is bleached to bleach the toner molecules distributed on the back surface of the base paper, remove the pattern on the back surface of the base paper, and retain the pattern that penetrates into the base paper to obtain the novel pattern-penetrating special paper. The whole process flow is simple, uses less raw materials and is easy to obtain, has a low process cost, has good production stability, and is conducive to large-scale production. DETAILED DESCRIPTION

[0020] Embodiment 1

[0021] A production process of a novel pattern-penetrating specialty paper comprises the following steps:

[0022] Step 1: Print the pattern on the back of the base paper. Use a penetrating coating and a gravure printing machine to print the pattern on the back of the base paper so that the pattern penetrates into the base paper. The printing speed of the gravure printing machine is 10-100 m / min. After gravure printing, keep the humidity and temperature of the base paper unchanged.

[0023] Step 2: Bleaching and drying the back surface of the infiltrated base paper, coating the back surface of the base paper with a bleaching agent through a dry coating machine, the coating speed of the dry coating machine is 30-60 m / min, and then drying the bleached base paper at a drying temperature of 20-50° C. to obtain a new pattern-infiltrated specialty paper;

[0024] Among them, the penetrating coating includes 20% α-sulfonic monocarboxylate, 20% alkylphenol polyoxyethylene ether, 8% water-soluble color powder, and the rest is water. α-sulfonic monocarboxylate is used as a penetrant, and alkylphenol polyoxyethylene ether is used as a dispersant; the bleaching agent is a hydrogen peroxide solution with a mass fraction of 40%.

[0025] The present invention adopts a penetrating coating to print a pattern, so that the pattern can penetrate into the base paper during the printing process. Since the penetrating agent generally has fixed hydrophilic and lipophilic groups and can be arranged in a direction on the surface of the solution, the surface tension of the base paper can be significantly reduced under the action of the penetrating agent, so that the molecules of the water-soluble color powder are first uniformly dissolved in water under the action of the dispersant, and then penetrate from the back surface of the base paper to the inside of the base paper under the action of the penetrating agent, and finally distributed from the inside of the base paper to the back surface; thereafter, the surface of the back of the base paper is bleached, and the bleaching agent and the coating molecules on the back surface of the base paper undergo an oxidation-reduction reaction, and the pattern on the back surface of the base paper is bleached and removed, so that the base paper only retains the color of the color powder that penetrates into the inside, that is, the pattern on the back surface of the base paper is removed, and the pattern that penetrates into the inside of the base paper is retained, thereby forming the novel pattern-penetrating special paper.

[0026] Embodiment 2

[0027] When other parts are the same as those of Example 1, the difference is that the penetrating coating comprises 10% by weight of α-sulfonic monocarboxylate, 20% by weight of alkylphenol polyoxyethylene ether, 8% by weight of water-soluble color powder, and the rest is water.

[0028] Embodiment 3

[0029] In the case where other parts are the same as those of Example 1, the difference is that the penetrating coating comprises 30% by weight of α-sulfonic monocarboxylate, 20% by weight of alkylphenol polyoxyethylene ether, 8% by weight of water-soluble color powder, and the rest is water.

[0030] In Examples 1 to 3, with the same weight portions of dispersant and water-soluble color powder, the weight portions of penetrant are adjusted, and the finished new pattern-penetrating specialty paper products of Examples 1 to 3 are compared: in Example 1, the weight portions of penetrant and dispersant are moderate, the water-soluble color powder can be completely penetrated into the base paper, the base paper presents a clear pattern, and the time required for bleaching the surface on the back of the base paper is moderate; in Example 2, the weight portion of penetrant is less, the water-soluble color powder is difficult to completely penetrate into the base paper, resulting in a lighter pattern color of the finished paper, and a darker color of the wastewater after gravure printing, with a certain amount of water-soluble color powder remaining in the wastewater that has not penetrated into the base paper; in Example 3, the weight portion of penetrant is more, the water-soluble color powder completely penetrates into the base paper, but the degree of penetration is high, and more bleaching time is required when coating and bleaching the surface on the back of the base paper.

[0031] Embodiment 4

[0032] In the case where other parts are the same as those of Example 1, the difference is that the penetrating coating comprises 20% by weight of α-sulfonic monocarboxylate, 10% by weight of alkylphenol polyoxyethylene ether, 8% by weight of water-soluble color powder, and the rest is water.

[0033] Embodiment 5

[0034] In the case where other parts are the same as those of Example 1, the difference is that the penetrating coating comprises 20% by weight of α-sulfonic monocarboxylate, 30% by weight of alkylphenol polyoxyethylene ether, 8% by weight of water-soluble color powder, and the rest is water.

[0035] The difference between Example 4 and Example 5 and Example 1 is that when the weight of the penetrant and the water-soluble toner are the same, the weight of the dispersant is adjusted, and the new pattern-penetrating specialty paper products of Example 4 and Example 5 are compared with Example 1: Example 4 has less dispersant and cannot be evenly dissolved in water, resulting in uneven penetration during gravure printing, with some areas containing more toner and other areas containing less toner, ultimately leading to uneven color of the finished paper; Example 5 has more dispersant, and the water-soluble toner has a high degree of dispersion in water, resulting in a lighter color of the printed pattern.

[0036] Embodiment 6

[0037] When other parts are the same as those of Example 1, the difference is that the penetrating coating comprises 20% by weight of α-sulfonic monocarboxylate, 20% by weight of alkylphenol polyoxyethylene ether, 5% by weight of water-soluble color powder, and the rest is water.

[0038] Embodiment 7

[0039] In the case where other parts are the same as those of Example 1, the difference is that the penetrating coating comprises 20% by weight of α-sulfonic monocarboxylate, 20% by weight of alkylphenol polyoxyethylene ether, 12% by weight of water-soluble color powder, and the rest is water.

[0040] The difference between Example 6 and Example 7 and Example 1 is that under the same weight of penetrant and dispersant, the weight of water-soluble toner is adjusted, and the new pattern-penetrating specialty paper products of Example 6 and Example 7 are compared with Example 1: Example 6 has less water-soluble toner, resulting in the color of the printed pattern being too light, affecting the visual effect of the finished paper; Example 7 has more water-soluble toner, which also results in a high toner content in the water, which cannot penetrate into the paper and causes powder falling, and the wastewater after gravure printing is dark in color, and a certain amount of water-soluble toner that failed to penetrate into the base paper remains in the wastewater.

[0041] In the above embodiments, the penetrant can also be at least one of anionic surfactants such as sodium secondary alkyl sulfonate, sodium palmitate methyl ester sulfonate, sodium dodecylbenzene sulfonate, etc., and the dispersant can also be at least one of nonionic surfactants such as fatty alcohol polyoxyethylene ether, alkyl alcohol amide, cetyl alcohol polyoxyethylene ether, lauryl alcohol polyoxyethylene ether, etc., and the specific amount used depends on the specific production requirements; the bleaching agent can also be at least one of sodium hypochlorite, potassium hypochlorite, potassium pyrosulfate, and peracetic acid, and the mass fraction of the bleaching agent is 20-80%. The use of the bleaching agent only determines the time required for bleaching the surface of the back of the base paper in step 2. As for the use of hydrogen peroxide solution, a hydrogen peroxide solution with a mass fraction of 20-60% is generally selected.

[0042] In addition, it should be noted that the names of the various parts of the specific embodiments described in this specification may be different, and any equivalent or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A production process for pattern-penetrating specialty paper, characterized in that The following steps are involved: Step 1: Print a pattern on the back of the base paper, and use a penetrating coating to penetrate the pattern into the base paper during printing. The penetrating coating includes a penetrant, a dispersant, a water-soluble color powder and water; Step 2: Bleaching and drying the surface of the back of the infiltrated base paper, coating the surface of the back of the base paper with a bleaching agent through a dry coating machine, and performing an oxidation-reduction reaction between the bleaching agent and the coating molecules on the back of the base paper to bleach and remove the pattern on the back of the base paper, and then drying the bleached base paper to obtain the pattern-infiltrated specialty paper.

2. The production process of pattern-permeable specialty paper according to claim 1, characterized in that: When printing a pattern on the back of the base paper in step 1, the pattern is printed on the back of the base paper by a gravure printing machine, and the humidity and temperature of the base paper are kept unchanged after gravure printing.

3. The production process of pattern-permeable specialty paper according to claim 2, characterized in that: The printing speed of the gravure printing machine is 10-100 m / min.

4. The production process of pattern-permeable specialty paper according to any one of claims 1 to 3, characterized in that: The components of the penetrating coating include, by weight, 10-30% of anionic surfactant, 10-30% of nonionic surfactant, 5-10% of water-soluble color powder, and the rest is water.

5. The production process of pattern-permeable specialty paper according to claim 4, characterized in that: The anionic surfactant is at least one of α-sulfonyl monocarboxylate, sodium secondary alkyl sulfonate, sodium methyl palmitate sulfonate, and sodium dodecylbenzene sulfonate.

6. The production process of pattern-permeable specialty paper according to claim 4, characterized in that: The nonionic surfactant is at least one of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, alkylolamide, cetyl alcohol polyoxyethylene ether, and lauryl alcohol polyoxyethylene ether.

7. The production process of pattern-permeable specialty paper according to claim 1, characterized in that: In the step 2, the coating speed of the dry coater is 30-60 m / min, and the drying temperature is 20-50° C.

8. The production process of pattern-permeable specialty paper according to claim 7, characterized in that: The bleaching agent is at least one of hydrogen peroxide, sodium hypochlorite, potassium hypochlorite, potassium pyrosulfate and peracetic acid, and the mass fraction of the bleaching agent is 20-80%.

9. The production process of pattern-permeable specialty paper according to claim 8, characterized in that: The bleaching agent is a hydrogen peroxide solution with a mass fraction of 20-60%.