CN111041890B

CN111041890B - Novel nano mineral moisture-retaining coating preparation process

Info

Publication number: CN111041890B
Application number: CN201911142784.0A
Authority: CN
Inventors: 李雪; 张恒伟; 慕红霞; 窦海成; 朱存真; 马永峰; 翟玉俊
Original assignee: Gansu Tobacco Industrial Co ltd
Current assignee: Gansu Tobacco Industrial Co ltd
Priority date: 2019-11-20
Filing date: 2019-11-20
Publication date: 2022-04-12
Anticipated expiration: 2039-11-20
Also published as: CN111041890A

Abstract

The invention belongs to the field of papermaking industry, and particularly relates to a preparation process of a novel nano mineral moisture-retaining coating; the method comprises the following steps: firstly, preparing modified bentonite by using a preparation machine; secondly, preparing a cross-linking agent and an initiator solution; taking a monomer solution with the mass fraction of 10%, adjusting the monomer solution to the pH value of 1-7 by using sodium hydroxide in an ice water bath, sequentially adding organic modified bentonite accounting for 2% -6% of the mass fraction of the monomer, 0.35% -0.7% of an initiator and 0.1-0.2% of a cross-linking agent under magnetic stirring, uniformly stirring, placing at the temperature of 60-80 ℃, stirring for 10min at constant temperature, standing until a rubber-like elastomer appears, drying, and cutting to prepare the nano mineral moisture-retaining coating; the preparation process is simple, and the prepared moisture-retaining coating has less water-absorbing resin consumption and higher water-absorbing multiplying power than common coatings.

Description

Novel nano mineral moisture-retaining coating preparation process

Technical Field

The invention belongs to the field of papermaking industry, and particularly relates to a preparation process of a novel nano mineral moisture-retaining coating.

Background

In dry areas in northwest China, most of cigarette products generally have the tobacco shred moisture loss fast, the smoke, taste and various sensory indexes of cigarettes are seriously affected, the moisture of the cigarette products is 12% when the cigarette products leave a factory, but due to the fact that the cigarette products are dry in the northwest China, cigarette tobacco materials (inner lining paper, frame paper, label paper and the like) can absorb the tobacco shred moisture and the tobacco shred moisture can be lost, the tobacco shred moisture is reduced to 7% or even lower through measurement, and the minimum moisture of the tobacco shred required by national standards is 8%. How to improve the moisture retention performance of cigarettes is widely concerned, and the range of research on the moisture retention technology of cigarettes mainly comprises the aspects of a moisture retention agent, a moisture retention auxiliary material, packaging, storage and the like. The cigarette wrapping paper serving as one of important materials in cigarette auxiliary materials has high application value in the aspect of maintaining the moisture stability of cigarettes. The sensory comfort of the cigarette can be improved by improving the aroma retention and moisture retention performance of the cigarette paper.

The bentonite is a clay mineral with a three-layer sheet structure, wherein the clay mineral is mainly composed of montmorillonite, aluminum oxygen octahedron is arranged in the middle of the montmorillonite, and silicon oxygen tetrahedron is arranged above and below the montmorillonite, main elements of the montmorillonite are Na, Al, O, Si and the like, certain cations such as Mg, Na, K, Cu and the like exist in a unit cell, and the cations have weak effect with the unit cell and are easy to exchange with other cations. Therefore, the bentonite has excellent physical properties including water absorption, swelling property, cohesiveness, adsorbability and the like, wherein the swelling property and the adsorbability have wide application values and are important indexes for measuring the quality of the bentonite.

The strong adsorbability and high expansibility of the modified bentonite are widely applied to a papermaking system, considerable superiority is shown, alkyl quaternary ammonium salt or other organic cations are introduced between montmorillonite layers to generate organic silicate by utilizing the exchangeability of cations between the montmorillonite layers, the exchanged organic silicate has hydrophilicity converted into lipophilicity, the surface energy of the silicate is reduced, the compatibility of organic phases and inorganic phases in the composite material is improved, the organic cations are larger, the organic cation replaces original interlayer metal ions, the interlayer distance of the montmorillonite is increased, the organic monomer molecules can enter favorably, the organic silicate can be further stripped into a structure sheet layer with a nano scale in the process of being mild with organic monomers or polymer melts, and the structure sheet layer is uniformly dispersed in a polymer matrix, so that the nano composite material is formed. The super absorbent resin is a novel high polymer material, can absorb water which is hundreds of times to thousands of times of the self weight, and is non-toxic, harmless and pollution-free. Has strong water absorption capacity and high water retention capacity, and the absorbed water can not be extruded by a simple physical method and can repeatedly release and absorb water. The super absorbent resin is a generic term for high molecular weight polymers having high water absorption and water retention properties. The polyacrylic acid super absorbent resin is a novel functional polymer material containing hydrophilic groups such as hydroxyl groups and carboxyl groups and a cross-linked network structure, can quickly absorb and maintain liquid water which is hundreds of times or even thousands of times of the self mass through hydration, has better water retention capacity at normal temperature, is not easy to lose water even in a pressurized state, and is widely applied to the fields of agriculture, medicine, gardens and physiological health products.

Disclosure of Invention

The invention provides a preparation process of a novel nano mineral moisture-retaining coating, which aims to solve the problems that cigarette moisture is easily absorbed in a cigarette package process in a dry area, and tobacco shreds are dried and have reduced smoking taste and sensory value due to the fact that the moisture of the cigarettes is balanced with the external dry environment through paper. The process is simple to operate, and the prepared nano mineral moisture-retaining coating is environment-friendly and has strong water absorption and water supplement capabilities. The prepared moisture-retaining coating has a strong water absorption function, and can release water stored in the material for cigarettes to cigarettes when coated on the material for cigarettes under the weather condition of a dry area; the moisture-keeping effect of the cigarette is realized.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a novel nano mineral moisture-retaining paint preparation process comprises the following steps;

firstly, preparing organic modified bentonite, adding bentonite into water, heating to 70 ℃, adding a modifier, stirring until white precipitate is separated out, washing the precipitate with water, drying in vacuum, grinding, and sieving with a 250-mesh sieve to obtain the organic modified bentonite, wherein the proportion of the water, the bentonite and the modifier is 35ml:2g:1 g;

secondly, preparing a cross-linking agent and an initiator solution, wherein the concentration of the cross-linking agent solution is 0.005 g/mL, and an inorganic peroxy initiator alpha-inorganic peroxy initiator beta redox system is used as an initiator, wherein the mass ratio of m alpha to m beta =19 to 11;

thirdly, preparing the nano mineral moisture-retaining coating, namely taking a monomer solution with the mass fraction of 10%, regulating the monomer solution to the pH value of 1-7 by using sodium hydroxide in an ice water bath, sequentially adding organic modified bentonite accounting for 2-6% of the mass fraction of the monomer, 0.35-0.7% of an initiator and 0.1-0.2% of a cross-linking agent under magnetic stirring, stirring uniformly, placing the mixture at the temperature of 60-80 ℃ for stirring at constant temperature for 10min, standing until a rubber-like elastomer appears, drying and cutting the rubber-like elastomer in an oven at the temperature of 100 ℃, and preparing the nano mineral moisture-retaining coating; the monomer is acrylic acid or corresponding salts thereof.

And (3) evaluating the success of the nano mineral moisture-retaining coating: weighing the nano mineral moisture-retaining paint m1, putting the nano mineral moisture-retaining paint m1 into a 1000 mL beaker filled with 500 mL deionized water, fully absorbing water for 24 hours, filtering and weighing the gel mass m2, and then calculating the water absorption rate of the nano mineral moisture-retaining paint.

Further, the bentonite used in the first step is an alkali bentonite.

Preferably, the alkali bentonite used in the first step is sodium bentonite or calcium bentonite, and the modifier used is one of octadecyl trimethyl ammonium bromide, dodecyl trimethyl ammonium bromide and hexadecyl trimethyl ammonium bromide.

Furthermore, in the first step, the modifier is added and then stirred for 10min at the rotating speed of 200r/min, and then stirred for 1h at the rotating speed of 500 r/min.

Furthermore, in the second step, the concentration of the solution prepared by the inorganic peroxy initiator alpha in the initiator is 0.001 g/mL; the concentration of the inorganic peroxy initiator beta prepared into a solution is 0.007 g/mL.

Further, the cross-linking agent is one of N, N-methylene bisacrylamide, N-hydroxymethyl acrylamide, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

Further, the inorganic peroxy initiator is potassium sulfate, ammonium persulfate or sodium persulfate. The initiator alpha is ammonium persulfate, sodium persulfate or potassium persulfate; the initiator beta is sodium bisulfite, ammonium bisulfite or potassium bisulfite.

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

the nano mineral moisture-retaining coating prepared by the preparation process has the highest water absorption rate of 925, good water absorption performance, less consumption compared with common water-absorbent resin and high water absorption rate. The nano mineral moisture-retaining coating prepared by the process has good expansion and water absorption properties, the preparation process is simple, and the nano mineral moisture-retaining coating has a good water replenishing effect when being used as a back coating of cigarette materials.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The present invention is further illustrated by the following specific examples.

Example 1

Modifying sodium bentonite, adding 10g of bentonite into 175ml of water, heating to 70 ℃, adding 5g of octadecyl trimethyl ammonium bromide, stirring at a high speed for 10min, stirring at a low speed for 1h to separate out white precipitate, washing the precipitate with water, drying in vacuum, grinding, and sieving with a 250-mesh sieve to obtain the organically modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 5 percent of the mass fraction of the monomers, 0.2 percent of initiator and 0.15 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption rate of the nano mineral moisture-retaining coating to be 234. The monomer used is acrylic acid. The cross-linking agent is N, N-methylene bisacrylamide. The initiator alpha is ammonium persulfate; the initiator beta is sodium bisulfite.

Example 2

Modifying calcium bentonite, adding 10g of bentonite into 175ml of water, heating to 70 ℃, adding 5g of dodecyl trimethyl ammonium bromide, stirring at a high speed for 10min, stirring at a low speed for 1h to separate out white precipitate, washing the precipitate with water, drying in vacuum, grinding, and sieving with a 250-mesh sieve to obtain the organically modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 6 percent of the mass fraction of the monomers, 0.35 percent of initiator and 0.15 percent of cross-linking agent in turn under magnetic stirring, stirring evenly, placing at 70 ℃ and stirring for 10min at constant temperature, standing until rubber-like elastic bodies appear, drying and chopping in a baking oven at 100 ℃, and measuring the water absorption multiplying power of the nano mineral moisture-retaining coating to be 765. The monomers used are acrylic acid, methacrylic acid. The cross-linking agent is N-hydroxymethyl acrylamide, and the initiator alpha is potassium persulfate; the initiator beta is potassium bisulfite.

Example 3

Modifying calcium bentonite, adding 10g bentonite into 175ml water, heating to 70 ℃, adding 5g modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying in vacuum, grinding, and sieving with 250 mesh sieve to obtain the organic modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 2 percent of the mass fraction of the monomers, 0.7 percent of initiator and 0.15 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption multiplying power of the nano mineral moisture-retaining coating to be 289. The monomer used was ethyl acrylate. The cross-linking agent is N-methylolacrylamide, and the initiator alpha is ammonium persulfate; the initiator beta is ammonium bisulfite.

Example 4

Modifying sodium bentonite, adding 10g of bentonite into 175ml of water, heating to 70 ℃, adding 5g of modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying and grinding in vacuum, and sieving with a 250-mesh sieve to obtain the organically modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 5 percent of the mass fraction of the monomers, 0.4 percent of initiator and 0.1 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption multiplying power of the nano mineral moisture-retaining coating to be 456. The monomer used is acrylic acid. The cross-linking agent is hydroxypropyl methacrylate, and the initiator alpha is sodium persulfate; the initiator beta is sodium bisulfite.

Example 5

Modifying calcium bentonite, adding 10g bentonite into 175ml water, heating to 70 ℃, adding 5g modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying in vacuum, grinding, and sieving with 250 mesh sieve to obtain the organic modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 4 percent of the mass fraction of the monomers, 0.4 percent of initiator and 0.15 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in an oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption rate of the nano mineral moisture-retaining coating to be 782. The monomers used are acrylic acid, methacrylic acid. The cross-linking agent is hydroxypropyl methacrylate, and the initiator alpha is sodium persulfate; the initiator beta is sodium bisulfite.

Example 6

Modifying calcium bentonite, adding 10g bentonite into 175ml water, heating to 70 ℃, adding 5g modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying in vacuum, grinding, and sieving with 250 mesh sieve to obtain the organic modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 5 percent of the mass fraction of the monomers, 0.5 percent of initiator and 0.2 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption rate of the nano mineral moisture-retaining coating to be 234. The monomer used was ethyl acrylate. The cross-linking agent is N-methylolacrylamide, and the initiator alpha is ammonium persulfate; the initiator beta is ammonium bisulfite.

Embodiment 7

Modifying sodium bentonite, adding 10g of bentonite into 175ml of water, heating to 70 ℃, adding 5g of modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying and grinding in vacuum, and sieving with a 250-mesh sieve to obtain the organically modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 5 percent of the mass fraction of the monomers, 0.4 percent of initiator and 0.05 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption rate of the nano mineral moisture-retaining coating to be 283. The monomer used is acrylic acid. The cross-linking agent is N-hydroxymethyl acrylamide, and the initiator alpha is potassium persulfate; the initiator beta is potassium bisulfite.

Example 8

Modifying sodium bentonite, adding 10g of bentonite into 175ml of water, heating to 70 ℃, adding 5g of modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying and grinding in vacuum, and sieving with a 250-mesh sieve to obtain the organically modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 5 percent of the mass fraction of the monomers, 0.4 percent of initiator and 0.15 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 70 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption multiplying power of the nano mineral moisture-retaining coating to be 925. The monomer used was methacrylic acid. The cross-linking agent is N-methylolacrylamide, and the initiator alpha is ammonium persulfate; the initiator beta is ammonium bisulfite.

Example 9

Modifying sodium bentonite, adding 10g of bentonite into 175ml of water, heating to 70 ℃, adding 5g of modifier, stirring for 10min at a high speed, stirring for 1h at a low speed, separating out white precipitate, washing the precipitate with water, drying and grinding in vacuum, and sieving with a 250-mesh sieve to obtain the organically modified bentonite. Taking a monomer solution with the mass fraction of 10% into a three-neck flask, and adjusting the pH value to 5 by using sodium hydroxide under the ice-water bath condition. Adding organic modified bentonite accounting for 5 percent of the mass fraction of the monomers, 0.4 percent of initiator and 0.05 percent of cross-linking agent into the mixture in turn under magnetic stirring, stirring the mixture evenly, placing the mixture at a constant temperature of 60 ℃ for stirring for 10min, standing the mixture until rubber-like elastic bodies appear, drying the mixture in a drying oven at 100 ℃, cutting the mixture into pieces, and measuring the water absorption multiplying power of the nano mineral moisture-retaining coating to be 569. The monomer used was methyl acrylate. The cross-linking agent is N-hydroxymethyl acrylamide, and the initiator alpha is potassium persulfate; the initiator beta is potassium bisulfite.

Claims

1. A novel nano mineral moisture-retaining paint preparation process is characterized by comprising the following steps;

firstly, preparing organically modified bentonite, adding bentonite into water, heating to 70 ℃, adding a modifier, stirring for 10min at a rotation speed of 200r/min after adding the modifier, and stirring for 1h at a rotation speed of 500 r/min; stirring until white precipitate is separated out, washing the precipitate, drying in vacuum, grinding, and sieving with 250 mesh sieve to obtain organic modified bentonite, wherein the ratio of water, bentonite and modifier is 35ml:2g:1 g;

secondly, preparing a cross-linking agent and an initiator solution, wherein the concentration of the cross-linking agent solution is 0.005 g/mL, and an inorganic peroxy initiator alpha-inorganic peroxy initiator beta redox system is used as an initiator, wherein the mass ratio of m alpha to m beta =19 to 11; the concentration of the solution prepared by the inorganic peroxy initiator alpha in the initiator is 0.001 g/mL; the concentration of the solution prepared by the inorganic peroxy initiator beta is 0.007 g/mL; the initiator alpha is ammonium persulfate, sodium persulfate or potassium persulfate; the initiator beta is sodium bisulfite, ammonium bisulfite or potassium bisulfite;

2. The preparation process of the novel nano mineral moisture-retaining coating according to claim 1, wherein the bentonite used in the first step is alkali bentonite.

3. The preparation process of the novel nano mineral moisture-retaining coating according to claim 2, wherein the alkali bentonite used in the first step is sodium bentonite or calcium bentonite, and the modifier is one of octadecyl trimethyl ammonium bromide, dodecyl trimethyl ammonium bromide and hexadecyl trimethyl ammonium bromide.

4. The process for preparing a novel nano mineral moisture-retaining coating according to claim 1, wherein the cross-linking agent is one of N, N-methylene bisacrylamide, N-methylolacrylamide, hydroxyethyl methacrylate and hydroxypropyl methacrylate.