阅读说明：本技术 一种增强型瓷砖胶用改性羟丙基甲基纤维素及其制备方法和应用 (Modified hydroxypropyl methyl cellulose for enhanced ceramic tile glue and preparation method and application thereof ) 是由 滕鲲 赵明 滕波 李青华 姜爱梅 赵建玉 孟兆武 于 2020-07-09 设计创作，主要内容包括：本发明公开了一种增强型瓷砖胶用改性羟丙基甲基纤维素,由以下质量百分比的原料制得：羟丙基甲基纤维素54％-94％、淀粉醚5％-40％、分散剂0.5％-3％和流变剂0.5％-3％；其中,羟丙基甲基纤维素由纤维素粉、粒碱、液碱、氯甲烷和环氧丙烷制得；制备方法为：(1)称取各原料；(2)将纤维素粉、粒碱、液碱、氯甲烷和环氧丙烷混合,进行醚化反应,然后再依次进行中和、洗涤、离心、干燥和粉碎,得到羟丙基甲基纤维素；(3)将羟丙基甲基纤维素、淀粉醚、分散剂和流变剂进行混合搅拌,即得。本发明所得产品质量稳定,具有改善瓷砖胶拉伸粘结强度的功能,应用于现代尺寸大、质量大的瓷砖,能够显著提高瓷砖使用的安全性。(The invention discloses a modified hydroxypropyl methyl cellulose for enhanced ceramic tile glue, which is prepared from the following raw materials in percentage by mass: 54 to 94 percent of hydroxypropyl methyl cellulose, 5 to 40 percent of starch ether, 0.5 to 3 percent of dispersant and 0.5 to 3 percent of rheological agent; wherein the hydroxypropyl methyl cellulose is prepared from cellulose powder, granular alkali, liquid alkali, chloromethane and propylene oxide; the preparation method comprises the following steps: (1) weighing the raw materials; (2) mixing cellulose powder, granular alkali, liquid alkali, chloromethane and epoxypropane, carrying out etherification reaction, and then sequentially carrying out neutralization, washing, centrifugation, drying and crushing to obtain hydroxypropyl methyl cellulose; (3) mixing and stirring hydroxypropyl methyl cellulose, starch ether, a dispersing agent and a rheological agent to obtain the hydroxypropyl methyl cellulose. The product obtained by the invention has stable quality, has the function of improving the tensile bonding strength of the tile adhesive, is applied to the modern large-size and large-quality tiles, and can obviously improve the safety of the use of the tiles.)

1. The modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue is characterized by being prepared from the following raw materials in percentage by mass: 54 to 94 percent of hydroxypropyl methyl cellulose, 5 to 40 percent of starch ether, 0.5 to 3 percent of dispersant and 0.5 to 3 percent of rheological agent;

the hydroxypropyl methyl cellulose is prepared from (by mass ratio) 1 (0.01-1.0): (0.02-2.1): (0.50-2.0): (0.01-1.5) cellulose powder, granular alkali, liquid alkali, methyl chloride and propylene oxide.

2. The modified hydroxypropyl methyl cellulose for the reinforced ceramic tile glue according to claim 1, wherein the starch ether is one or a mixture of more of a mono-starch ether, a di-starch ether and a tri-starch ether.

3. The modified hydroxypropyl methyl cellulose for the reinforced tile glue according to claim 1, wherein the dispersant is any one or a mixture of polyacrylamide, polyvinyl alcohol and polyethylene oxide.

4. The modified hydroxypropyl methyl cellulose for the enhanced tile glue according to claim 1, wherein the rheological agent is any one or a mixture of guar gum, arabic gum, carrageenan and xanthan gum.

5. The modified hydroxypropyl methyl cellulose for the enhanced tile glue according to claim 1, wherein the cellulose powder is any one or a mixture of cotton cellulose, wood cellulose, bamboo cellulose and straw cellulose;

the degree of polymerization of the cellulose powder is 500-8000;

the grain diameter of the cellulose powder is 0.18-0.30 mm;

the bulk density of the cellulose powder was 150-200 g/L.

6. A modified hydroxypropyl methylcellulose for reinforced tile glue according to claim 1, wherein the particulate alkali is a particulate alkali metal hydroxide;

the alkali metal hydroxide is sodium hydroxide and/or potassium hydroxide;

the particle size of the granular alkali is 0.3-2.0 mm.

7. A modified hydroxypropyl methylcellulose for reinforced tile glue according to claim 1, wherein the liquid alkali is an aqueous solution of alkali metal hydroxide;

the alkali metal hydroxide is sodium hydroxide and/or potassium hydroxide;

the mass concentration of the alkali metal hydroxide in the liquid alkali is 40-60%.

8. A preparation method of modified hydroxypropyl methyl cellulose for enhanced ceramic tile glue is characterized by comprising the following steps:

(1) weighing the raw materials according to the mass ratio of the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile adhesive of any one of claims 1 to 7;

(2) mixing cellulose powder, granular alkali, liquid alkali, chloromethane and epoxypropane, and sequentially carrying out etherification reaction, neutralization, washing, centrifugation, drying and crushing to obtain hydroxypropyl methyl cellulose;

(3) and mixing and stirring hydroxypropyl methyl cellulose, starch ether, a dispersing agent and a rheological agent to obtain the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue.

9. The preparation method of the modified hydroxypropyl methyl cellulose for the enhanced tile adhesive according to claim 8, wherein in the step (2), the etherification reaction is divided into a one-stage etherification reaction and a two-stage etherification reaction;

the pressure of the first-stage etherification reaction is 1.8-2.0MPa, the temperature is 55-65 ℃, and the time is 0.5-1.5 h;

in the step (2), the pressure of the two-stage etherification reaction is 2.3-2.5MPa, the temperature is 75-85 ℃, and the time is 0.5-1.5 h;

in the step (3), the rotation speed of the mixing and stirring is 10-70r/min, and the time is 40-60 min.

10. The use of the modified hydroxypropyl methylcellulose for the reinforced tile glue according to claim 1 in the preparation of the reinforced tile glue, wherein the modified hydroxypropyl methylcellulose for the reinforced tile glue accounts for 0.2 to 0.5 percent by weight of the reinforced tile glue.

Technical Field

The invention relates to the technical field of building materials, in particular to modified hydroxypropyl methyl cellulose for enhanced ceramic tile glue and a preparation method and application thereof.

Background

Ceramic tiles are used as decorative materials, the market is wide, but as the specialization degree of the ceramic tile market is continuously improved, more and more consumers pursue the seamless effect of wall decoration, so that large-size ceramic tiles are increasingly popular, and meanwhile, the increasing popularity of large-area residential buildings also promotes the beauty of the large-size ceramic tiles. With the increasing size and mass of tiles, the requirements for safety are also increasing, the requirements of traditional tile adhesives are difficult to meet, and then novel tile adhesives are rapidly developed.

The main causes of the detachment of the tile are: (1) carrying out dry shrinkage deformation on the new concrete base layer; (2) external factors such as building settlement and creep; (3) the sudden change of temperature generates deformation; (4) the water vapor in the porous ceramic tile expands to generate shear stress; (5) the surface of the ceramic tile is smooth, and the mechanical anchoring force between the adhesive and the ceramic tile is very small, so that the adhesive force is damaged due to small stress generated by other reasons. Aiming at the problems, the common ceramic tile adhesive can only meet a part of requirements, and for a single vitrified tile with a large area, such as more than 600mm multiplied by 600mm, the phenomena of hollowing, brick falling and the like can often occur when the common ceramic tile adhesive is used for pasting the high-quality ceramic tiles due to the large shrinkage rate. Therefore, for high-quality tiles, reinforced tile glue is needed for pasting.

Hydroxypropyl methyl celluloseThe Cellulose (HPMC) is a Cellulose mixed ether variety with the yield, the dosage and the quality rapidly improved in recent years, and is nonionic Cellulose mixed ether prepared by alkalizing cotton and wood, etherifying epoxypropane and Methyl chloride and the like, and the HPMC has the molecular structure of [ C [₆H₇O₂(OH)_3～m～n(OCH₃)_m(OCH₂CHOHCH₃)_n]_x. The current HPMC production process can be divided into two main categories: liquid phase processes and gas phase processes. The liquid phase method has small internal pressure of equipment, low requirement on the bearing capacity of the equipment and small danger, the cellulose is soaked in the alkali liquor to obtain the alkali cellulose which is fully swelled and uniformly alkalized, the alkali liquor has good infiltration and swelling on the cellulose, a product with uniform substitution degree and viscosity can be obtained, the variety is easy to replace, but the reactor cannot be too large (generally 15 m)³Below), the production capacity is low, a plurality of reactors are required to be added for improving the yield, a large amount of organic solvent is required as a carrier in the reaction process, the reaction time is long (generally more than 10 hours), and the solvent distillation recovery and the time cost are increased. The gas phase method has compact equipment, high yield of single batch, short reaction time (generally 5-8 hours) compared with the liquid phase method because the reaction is carried out in a horizontal high-pressure kettle, no complex solvent recovery system is needed, redundant methyl chloride and byproduct dimethyl ether enter the recovery system in a gaseous form after the reaction is finished and are respectively recovered and reused, the labor cost is low, the labor intensity is low, the production cost is lower than that of the liquid phase method, but the equipment and automatic control investment is large, the technical content is high, and the investment and construction cost is large.

Therefore, the problem to be solved by those skilled in the art is how to provide a modified hydroxypropyl methyl cellulose for reinforced tile glue and a preparation method thereof.

Disclosure of Invention

In order to make up the defects of the prior art, the invention provides the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue and the preparation method and the application thereof, the complicated operation of multi-step etherification in the preparation of the existing modified hydroxypropyl methyl cellulose is changed, only one-step etherification treatment is needed through the control of special operation conditions, and because the physical modification step is continuously added, a product with better performance is obtained, and the tensile bonding strength of the ceramic tile glue is obviously improved; meanwhile, compared with the prior art, the operating conditions of one-step etherification treatment are obviously different, the alkali concentration of the system is improved by adding granular alkali under the condition of not adding inhibitor dimethyl ether, the etherification efficiency of the etherifying agent is improved, meanwhile, the etherification reaction is carried out in sections under higher pressure, the etherification efficiency of the etherifying agent is further improved while the product uniformity is improved, the production cost is reduced under the condition of not prolonging the reaction time, and the problems in the prior art are solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue is prepared from the following raw materials in percentage by mass: 54 to 94 percent of hydroxypropyl methyl cellulose, 5 to 40 percent of starch ether, 0.5 to 3 percent of dispersant and 0.5 to 3 percent of rheological agent; wherein, the hydroxypropyl methyl cellulose is prepared by cellulose powder, granular alkali, liquid alkali, chloromethane and epoxypropane with the mass ratio of 1 (0.01-1.0): (0.02-2.1): 0.50-2.0): 0.01-1.5, preferably, the hydroxypropyl methyl cellulose is prepared by cellulose powder, granular alkali, liquid alkali, chloromethane and epoxypropane with the mass ratio of 1 (0.1-0.7): 0.1-1.0): 0.55-1.7): 0.05-1.2.

Further, the above-mentioned starch ether is any one or a mixture of several of a mono-starch ether (having one substituent, for example, carboxymethyl starch, hydroxypropyl starch, hydroxyethyl starch, etc.), a di-starch ether having two substituents, for example, carboxymethyl hydroxypropyl starch, hydroxypropyl hydroxyethyl starch, etc.), and a tri-starch ether (having three substituents, for example, carboxymethyl hydroxypropyl hydroxyethyl starch, hydroxypropyl hydroxyethyl ethyl starch, hydroxypropyl hydroxyethyl methyl starch, etc.).

The ceramic tile glue has the further beneficial effects that the starch ether has the effects of improving the anti-sliding property of the ceramic tile glue and prolonging the opening time of the ceramic tile glue. The starch ether selected by the invention contains various hydrophilic groups, so that the content of branched chain substituent groups is increased, the starch ether can generate a synergistic effect with a straight chain structure of hydroxypropyl methyl cellulose, the water retaining capacity of the tile adhesive is improved, the opening time of the tile adhesive is prolonged, and meanwhile, the various branched chain substituent groups of the starch ether increase the steric hindrance of the tile adhesive and improve the anti-sliding performance of the tile adhesive.

Further, the dispersant is any one or a mixture of several of polyacrylamide, polyvinyl alcohol and polyethylene oxide, preferably any one or a mixture of several of anionic polyacrylamide, nonionic polyacrylamide, polyvinyl alcohol and polyethylene oxide.

The further beneficial effect is that the dispersant has the effect of increasing the bonding strength of the tile adhesive. The dispersing agent selected by the invention has excellent water solubility and good compatibility with cellulose ether, can improve the water retention of cement slurry, greatly improve the transportability of the cement slurry, inhibit the flying of dust and improve the production environment.

Further, the rheological agent is one or more of guar gum, arabic gum, carrageenan and xanthan gum.

The rheological agent has the further beneficial effects that the rheological agent has the effects of regulating the viscosity of the product and improving the stability of the slurry by cooperating with other components. The selected rheological agents have excellent water solubility and good compatibility with cellulose ether, can improve the water retention of cement slurry and enhance the stability of the cement slurry to heat, acid, alkali, enzyme and salt.

Further, the cellulose powder is any one or a mixture of more of cotton cellulose, wood cellulose, bamboo cellulose and straw cellulose, preferably any one or a mixture of more of cotton cellulose, wood cellulose and bamboo cellulose, more preferably cotton cellulose and/or wood cellulose, and further preferably cotton cellulose; the degree of polymerization of the cellulose powder is 500-8000, preferably 1000-5000, more preferably 2400-3000; the particle size of the cellulose powder is 0.18-0.30mm, preferably 0.212-0.250 mm; the bulk density of the cellulose powder was 150-200 g/L.

The cellulose powder is used as the main reaction raw material of cellulose ether, is in a macromolecular straight-chain structure and has the function of keeping moisture. The cellulose powder selected by the invention is a green renewable resource, has huge reserves and is easy to prepare; the selected polymerization degree range has good reactivity, and the treatment after the reaction is smooth; the selected particle size is easy to permeate in a reaction system, the reaction efficiency is high, and the discharging is smooth; the bulk density is selected to be evenly dispersed in a reaction system, so that mass and heat transfer are easier, and the reaction efficiency is high.

Further, the particulate alkali is a particulate alkali metal hydroxide; the alkali metal hydroxide is preferably sodium hydroxide and/or potassium hydroxide, more preferably sodium hydroxide; the particle size of the granular alkali is 0.3-2.0mm, preferably 0.4-1.5mm, and more preferably 0.5-1.0 mm.

The method has the further beneficial effects that the granular alkali has the effects of increasing the concentration of the alkali liquor and accelerating the reaction speed. The granular alkali selected by the invention is easy to be water, has higher solubility and dissolution speed, and can shorten the alkali dissolving time; the selected particle size has good fluidity, convenient operation, difficult dust generation and rapid dissolution.

Further, the liquid alkali is an aqueous solution of an alkali metal hydroxide; the alkali metal hydroxide is preferably sodium hydroxide and/or potassium hydroxide, more preferably sodium hydroxide; the mass concentration of the alkali metal hydroxide in the liquid alkali is 40 to 60%, preferably 45 to 55%, more preferably 48 to 52%, and still more preferably 50%.

The method has the further beneficial effects that water in the liquid caustic soda is used as a reaction dispersant, so that the materials react more uniformly, and the product quality is improved; the alkali in the liquid alkali has the function of activating hydroxyl in cellulose molecules, so that the cellulose is converted into alkali cellulose for subsequent etherification reaction. The liquid alkali selected by the invention has higher solubility; the liquid alkali with the mass concentration selected by the invention has good fluidity at room temperature, is beneficial to pumping, has high alkali concentration and high reaction efficiency of a system, and can improve the utilization rate of an etherifying agent.

A preparation method of modified hydroxypropyl methyl cellulose for enhanced ceramic tile glue specifically comprises the following steps:

(1) weighing the raw materials according to the mass ratio of the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue;

(2) mixing cellulose powder, granular alkali, liquid alkali, chloromethane and propylene oxide, sequentially carrying out first-stage etherification reaction and second-stage etherification reaction, and then sequentially carrying out neutralization, washing, centrifugation, drying and crushing to obtain hydroxypropyl methyl cellulose;

(3) mixing and stirring hydroxypropyl methyl cellulose, starch ether, a dispersing agent and a rheological agent to obtain the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue.

Further, in the step (2), the pressure of the first-stage etherification reaction is 1.8-2.0MPa, the temperature is 55-65 ℃, and the time is 0.5-1.5 h; the pressure of the two-stage etherification reaction is 2.3-2.5MPa, the temperature is 75-85 ℃, and the time is 0.5-1.5 h.

The method has the further beneficial effects that the pressure of the etherification reaction at one stage is 1.8-2.0MPa, which is more beneficial to the reaction of propylene oxide and improves the etherification efficiency of the propylene oxide; the pressure of the two-stage etherification reaction is 2.3-2.5MPa, which is more beneficial to the reaction of methyl chloride and improves the etherification efficiency of the methyl chloride. The invention adopts the reaction mode of two pressure stages, improves the uniformity of the reaction, shortens the reaction time of the two pressure stages due to high reaction pressure and improved etherification efficiency, keeps the total time of the etherification reaction within 3h, improves the production efficiency, reduces the production cost, and ensures the safety of the reaction because the whole reaction process is carried out in a reactor with the pressure resistance of 2.8-3.5 MPa.

Further, the step (2) further comprises the following operation steps after the etherification reaction is finished: recovering unreacted etherifying agent by a three-stage condensation recovery process, directly relieving pressure and condensing and recovering the etherifying agent at the first stage, and relieving the pressure of the reactor from 2.3-2.5MPa to 0.75-1.1 MPa; secondary compression, condensation and recovery, and pressure relief of the reactor from 0.75-1.1MPaMPa to 0.1-0.25 MPa; three-stage vacuum and compression condensation recovery, and relieving the pressure of the reactor from 0.1-0.25MPa to (-0.08) - (-0.1) MPa.

The method has the further beneficial effects that the consumption of the etherifying agent can be reduced by the recovery mode of the etherifying agent, so that the pressure relief process of the high-pressure kettle is smoother, safer and more environment-friendly, and meanwhile, the etherifying agent is recycled, so that the utilization rate of the etherifying agent is improved, and the production cost is reduced.

Further, in the step (2), the neutralization process is as follows: adding acetic acid and/or hydrochloric acid, and adjusting pH of the material to 6-8.

The method has the further beneficial effects that the neutralization step is used for adjusting the reaction system to be neutral, so that the subsequent treatment of materials is facilitated, and the pH value of the final product is stabilized to be neutral. The acid selected by the invention is conventional, is easy to pump and weak in acidity, is beneficial to reducing the acidic degradation of materials and stabilizing the viscosity of products, and meanwhile, the salt generated in the neutralization process is easy to dissolve in water and is more beneficial to subsequent washing and removal.

Further, in the step (2), the washing process is as follows: washing with water at 80-95 deg.C, preferably 85-95 deg.C, more preferably 90-95 deg.C; the water adding amount is 6-12 times of the mass of the materials, and 8-10 times of the mass of the materials is preferred.

The washing method has the further beneficial effects that the washing effect of the method is to remove salts and other byproducts generated in the reaction, so that the product purity is improved, and meanwhile, the reaction kettle is washed, so that the next feeding is convenient. The water adding temperature selected by the invention can ensure that the materials and the water are fully separated, the dissolving speed of the salt is improved, and the washing efficiency is increased; the selected water adding amount can thoroughly clean the reaction kettle, no residue is left at the bottom of the reaction kettle, and simultaneously salt and other byproducts in a reaction product are fully dissolved, so that the ash content of a final product is reduced.

Further, in the step (2), the centrifugation process is as follows: the material is centrifuged at 2800-.

The method has the further beneficial effects that the centrifugation step is used for separating the materials from the salt-containing wastewater, after centrifugation, the materials with moisture content of 45-55% enter a drying procedure, and the salt-containing wastewater enters a sewage treatment procedure. The centrifugal rotating speed selected by the invention can efficiently separate the materials and the salt-containing wastewater, thereby ensuring smooth discharging; the selected centrifugal time can enable the centrifugal process to be smoothly carried out, the smooth connection of the front process and the rear process is guaranteed, and the utilization rate of equipment is improved.

Further, in the step (2), the drying process is as follows: drying the materials at 80-100 deg.C for 1.5-2.5 h.

The method has the further beneficial effects that the drying step of the method has the function of removing the moisture contained in the centrifugal materials, and the moisture of the final product is controlled to be below 5%. The drying temperature selected by the invention can ensure the rapid drying of the centrifugal material and reduce the material degradation in the drying process; the drying process can be smoothly carried out by selecting time, the smooth connection of the front process and the rear process is guaranteed, and the utilization rate of equipment is improved.

Further, in the step (2), the crushing process is as follows: pulverizing the materials to obtain powder with particle size of 0.125-0.180 mm.

The method has the further beneficial effects that the crushing step of the method has the effects of reducing the roughness of the materials and improving the fineness and the bulk density of the materials. The particle size selected by the invention improves the fineness and the bulk density of the material, and the product has better fluidity and texture and is easy to package.

Further, in the step (3), the rotation speed of mixing and stirring is 10-70r/min, and the time is 40-60 min.

The mixing and stirring effect of the invention is to uniformly mix the hydroxypropyl methyl cellulose, the starch ether, the dispersant and the rheological agent to achieve the purpose of physical modification. The mixing and stirring speed and time selected by the invention can ensure that all components are fully mixed to obtain a product with uniform mixing.

The application of the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue in preparing the enhanced ceramic tile glue is characterized in that the modified hydroxypropyl methyl cellulose for the enhanced ceramic tile glue accounts for 0.2-0.5% of the enhanced ceramic tile glue in percentage by mass.

According to the technical scheme, compared with the prior art, the invention has the following beneficial effects:

1. the invention does not need any redundant solvent and solvent recovery system in the preparation process from the raw material (cellulose) to the product (modified hydroxypropyl methyl cellulose), takes water in the raw material (cellulose) and a small amount of water in liquid alkali as the solvent of alkali, avoids using a large amount of solvent and water when the modified hydroxypropyl methyl cellulose is prepared by the traditional liquid phase method, condensing and recycling etherifying agent and byproduct dimethyl ether after etherification reaction, sending washing wastewater into a sewage treatment system, preparing the product by high pressure reaction, greatly shortening the time for preparing the modified hydroxypropyl methyl cellulose by the traditional liquid phase method, improving the use efficiency of the etherifying agent, having simple process and equipment, easy operation, no three wastes discharge, environmental protection, stable quality of the obtained modified hydroxypropyl methyl cellulose product and the function of improving the tensile bonding strength of tile glue, the ceramic tile is applied to the modern ceramic tile with large size and large mass, the use safety of the ceramic tile can be obviously improved, and the requirements of customers are met.

2. According to the invention, raw material cellulose and various etherifying agents are subjected to one-step etherification chemical modification simultaneously to obtain a pure hydroxypropyl methyl cellulose, and then the pure hydroxypropyl methyl cellulose is subjected to physical mixing modification continuously through specific mixing amount of starch ether, a dispersing agent and a rheological agent to obtain the modified hydroxypropyl methyl cellulose. Compared with the prior art, the modified hydroxypropyl methyl cellulose prepared by the preparation method provided by the invention is used for enhancing the tile glue, and can obviously improve the tensile bonding strength of the tile glue.

3. Compared with the existing modification method, the preparation method of the invention has obvious differences in operation conditions, especially in the feeding mode and etherification reaction pressure of chemical modification, the existing method generally adds inhibitor dimethyl ether to inhibit the occurrence of side reactions, the problems of reduced etherification efficiency, increased cost and increased side reactions can be caused if dimethyl ether is not added, in addition, the etherification reaction pressure in the existing method is generally below 2.35MPa, the reaction is carried out in one pressure stage, the problem of poor reaction uniformity exists, and if the reaction is carried out in partial pressure stage, the problems of prolonged reaction time, reduced production efficiency and increased cost can be caused in the pressure-resistant range of the existing reactor. Under the condition of not adding inhibitor dimethyl ether, the invention improves the alkali concentration of the system by adding granular alkali, accelerates the forward reaction, inhibits the occurrence of side reaction, improves the etherification efficiency, reduces the cost and simplifies the recycling step of dimethyl ether. In addition, the pressure of the etherification reaction is higher than 2.5MPa, the reaction is carried out in two pressure stages, the pressure of the etherification reaction in one stage is 1.8-2.0MPa, the reaction of propylene oxide is more favorably carried out, the etherification efficiency of propylene oxide is improved, the pressure of the etherification reaction in two stages is 2.3-2.5MPa, the reaction of methyl chloride is more favorably carried out, the etherification efficiency of methyl chloride is improved, the reaction mode in two pressure stages improves the uniformity of the reaction, and meanwhile, the reaction time in two pressure stages is shortened due to the high reaction pressure and the improved etherification efficiency, so that the total time of the etherification reaction is maintained within 3h, the production efficiency is improved, the production cost is reduced, and meanwhile, the whole reaction process is carried out in a reactor with the pressure resistance of 2.8-3.5MPa, so that the safety of the reaction is ensured; the modified treatment process ensures the smooth and efficient operation of the preparation method, simplifies the operation steps and saves resources and energy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a process flow diagram of modified hydroxypropyl methyl cellulose for enhanced tile glue of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following examples and comparative examples, the hydroxypropylmethylcellulose viscosity is a 2% aqueous solution viscosity (wet viscosity) measured at 20 ℃ with a model B RVT viscometer, and the starch ether viscosity is a 5% aqueous solution viscosity (dry viscosity) measured at 20 ℃ with a model B LVT viscometer.