CN112720787B

CN112720787B - Preparation process of flaky dry mortar and flaky dry mortar

Info

Publication number: CN112720787B
Application number: CN202011560537.5A
Authority: CN
Inventors: 迟碧川; 罗文斌; 王新平; 高鹏; 陈伯如; 郑阳
Original assignee: China Institute of Building Standard Design and Research Co Ltd
Current assignee: China Institute of Building Standard Design and Research Co Ltd
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2022-08-02
Anticipated expiration: 2040-12-25
Also published as: CN112720787A

Abstract

The invention is suitable for the field of building mortar, and provides a preparation process of flaky dry mortar and the flaky dry mortar, which comprises the following steps: mixing the dry mixture with the glue solution to obtain a wet mixture; adhering the wet mixed material to one side or two sides of the plane of the support body to obtain wet sheet mortar; drying and hardening the wet sheet mortar to remove part or all of the solvent in the wet sheet mortar to obtain sheet dry mortar; wherein the dry mixture is at least obtained by mixing inorganic cementing materials and aggregates; the glue solution is obtained by dissolving a water-soluble binder in a solvent. The invention can ensure that the flaky dry mortar has enough strength, simultaneously has lower product cost, has higher dissolving speed after meeting water, and has more types of selectable water-soluble binders.

Description

Preparation process of flaky dry mortar and flaky dry mortar

Technical Field

The invention relates to the field of building mortar, in particular to a preparation process of flaky dry mortar and the flaky dry mortar.

Background

The dry-mixed mortar is dry powder formed by mixing raw materials such as cementing materials, aggregates, additives and the like, and is one of the materials with the largest use amount in the building engineering. However, it presents two major problems in its application: firstly, produce serious raise dust pollution when adding water mix at the job site, secondly, the product form of discrete form and great raw materials density difference lead to the component easily to segregate, and the distribution is inhomogeneous, and product quality is unstable.

In order to solve the above technical problems, a solution for preparing sheet-like dry mortar by using a hot-melt method has been proposed in the prior art, for example, in patent EP2994283B1, water-soluble hot-melt adhesive powder is added to dry-mixed mortar raw materials and mixed to form a new mixture, the mixture is heated to melt the water-soluble hot-melt adhesive therein, and then the mixture is pressed into a sheet in a mold and cooled, so that other mortar raw materials are consolidated into a whole by means of the solidified water-soluble hot-melt adhesive. The sheet dry mortar prepared by the method can be quickly dissolved into a wet mortar state when meeting water during application, and then the construction operation same as that of the traditional mortar can be carried out. The flaky dry mortar does not have a powder mixing link in application, so that dust pollution is avoided. In addition, the flaky shape can effectively maintain the uniformity of the raw material components, so that the product has better quality stability.

However, the above technical solutions have the main problems: the reason why more water-soluble hot melt adhesive needs to be added is that in the process of preparing the flaky dry mortar, the mixture needs to be heated to melt the water-soluble hot melt adhesive in the mixture, however, the water-soluble hot melt adhesive in a molten state has high viscosity and poor fluidity, and the diffusion capability in the gaps of the particles of the mortar mixture is poor, so that in order to enable the flaky dry mortar to obtain enough cohesive force to have enough strength, the mixture needs to contain a high proportion of water-soluble hot melt adhesive to form a dense enough binder network to ensure the strength of the flaky dry mortar, otherwise, the flaky dry mortar is extremely easy to damage in the transportation and handling processes. However, the high-content water-soluble hot melt adhesive not only obviously increases the product cost, but also causes the slow melting speed, and has adverse effect on the mechanical property of the hardened mortar.

In addition, in the technical scheme, the types of the selectable water-soluble hot melt adhesives are less. The reason for this is as follows: most of the water-soluble hot melt adhesives have the melting point higher than 100 ℃, the setting time is shortened rapidly when the heated temperature of cement exceeds 100 ℃, the false setting phenomenon occurs, and other organic additives in the mortar often have the changes of discoloration, embrittlement and the like when the heated temperature exceeds 100 ℃, so that the performance of the mortar is adversely affected. Therefore, the above technical scheme can only select the water-soluble hot melt adhesive with the melting point below 100 ℃, and meanwhile, in order to ensure that the flaky dry mortar does not become soft or even melt in the high-temperature environment in summer, the melting point of the water-soluble hot melt adhesive is at least required to be higher than 60 ℃. However, the types of water-soluble hot melt adhesives having a melting point in the range of 60 to 100 ℃ and having practical value are few.

In conclusion, in the existing process for preparing the sheet-shaped dry mortar by using the hot melting method, the sheet-shaped dry mortar has lower product cost while having enough strength, has higher melting speed after meeting water, and has few types of water-soluble hot melt adhesives.

Disclosure of Invention

The invention aims to overcome the defects of the existing preparation process of the sheet dry mortar and provides the preparation process of the sheet dry mortar and the sheet dry mortar.

In a first aspect, the invention provides a preparation process of flaky dry mortar, which comprises the following steps:

step S10: mixing the dry mixture with the glue solution to obtain a wet mixture;

step S20: adhering the wet mixed material in the step S10 to one side or two sides of the plane of the support body to obtain wet sheet mortar;

step S30: drying and hardening the wet sheet mortar in the step S20 to remove part or all of the solvent in the wet sheet mortar to obtain sheet dry mortar;

wherein the dry mixture is at least obtained by mixing inorganic cementing materials and aggregates; the glue solution is obtained by dissolving a water-soluble binder in a solvent.

Optionally, the dry mixture is obtained by mixing at least one of admixtures, additives and fibers with the inorganic gelling material and the aggregate.

Optionally, the admixture is at least one of fly ash, slag powder, silica fume, zeolite powder, desulfurized gypsum, limestone powder, steel slag powder and phosphorous slag powder; the additive is at least one of a water-retaining agent, a redispersible latex powder, an early strength agent, a retarder, an accelerator, a waterproof agent, a water reducing agent, an antifreezing agent, a disintegrating agent, an expanding agent and a shrinkage reducing agent; the fibers are at least one of carbon fibers, glass fibers, steel fibers and polymer fibers.

Optionally, the dry blend comprises, by weight: 15-70 parts of inorganic cementing material, 15-85 parts of aggregate, 0-25 parts of admixture, 0-6 parts of additive and 0-5 parts of fiber; preferably, the fiber-reinforced composite material comprises 20-50 parts of inorganic cementing materials, 35-75 parts of aggregates, 0-15 parts of admixtures, 0-4 parts of additives and 0-3 parts of fibers.

Optionally, the solvent comprises an organic solvent, or the solvent comprises an organic solvent and water, wherein the weight ratio of the organic solvent to the water is 1 (0-7), preferably 1 (0-4).

Optionally, the weight ratio of the water-soluble binder to the solvent in the glue solution is 1 (1-35), preferably 1 (3-25).

Optionally, the water-soluble binder is at least one of vegetable gum, animal gum, microbial gum, modified cellulose, polymeric water-soluble resin and condensed water-soluble resin; preferably, the water-soluble binder is at least one of natural starch, seaweed gel and modified starch.

Optionally, the weight ratio of the dry mixture to the glue solution in the step S10 is 100 (6-30), preferably 100 (8-25).

Optionally, the support is at least one of an inorganic fiber mesh, a polymer mesh, a metal mesh, or a soluble film.

In a second aspect, the invention provides a sheet-like dry mortar prepared by the preparation process as described in one of the above.

The technical scheme adopted for preparing the flaky dry mortar has the following advantages:

1. in the invention, before the wet mixture is obtained, the water-soluble binder is dissolved in the solvent in advance, so that when the dry mixture is mixed with the glue solution, the water-soluble binder has better fluidity and better diffusion capacity in the gaps among the particles of the dry mixture, a sufficiently dense binder network can be formed, and the finally formed flaky dry mortar has higher strength;

2. in the invention, because the water-soluble binder has better fluidity, the strength of the sheet-shaped dry mortar is not required to be improved by increasing the using amount of the water-soluble binder, so that the product cost can be saved;

3. in the invention, the water-soluble binder does not need to be heated to promote the melting, thereby saving more energy;

4. in the invention, more water-soluble adhesives can be selected, the selection range of raw materials is wider, and the production is facilitated.

Drawings

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

FIG. 1 is a flow chart of the preparation of a sheet-like dry mortar in an embodiment of the present invention;

FIG. 2 is a first schematic view of a failure load testing method;

FIG. 3 is a second schematic view of the failure load testing method.

Detailed Description

The following description provides many different embodiments, or examples, for implementing different features of the invention. The particular examples set forth below are illustrative only and are not intended to be limiting.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As shown in fig. 1, the preparation process of the sheet-like dry mortar in the embodiment of the present invention is:

wherein the dry mixture is obtained by mixing at least inorganic cementing materials and aggregates; the glue solution is obtained by dissolving a water-soluble binder in a solvent;

in the embodiment of the invention, before the wet mixture is obtained, the water-soluble binder is dissolved in the solvent in advance, so that when the dry mixture is mixed with the glue solution, the water-soluble binder has better fluidity and better diffusion capacity in the gaps of the particles of the dry mixture, a sufficiently dense binder network can be formed, and the finally formed flaky dry mortar has higher strength; on the other hand, because the water-soluble binder has better fluidity, the strength of the sheet-shaped dry mortar is not required to be improved by increasing the using amount of the water-soluble binder, so that the product cost can be saved; in yet another aspect, embodiments of the present invention may not require the heating of the water-soluble binder to facilitate its melting, and thus may be more energy efficient; finally, the water-soluble adhesive has more types, and the embodiment of the invention has wider selection range of raw materials and is beneficial to production.

It is understood that, in the step S10, when the dry mixture is mixed with the glue, there are many mixing manners, such as stirring and mixing, and dipping and mixing, and the mixing manner of the dry mixture and the glue is not limited in the present invention.

It is worth mentioning that the inorganic gelling material can be inorganic gelling materials commonly used in the art, such as cement, lime, gypsum, etc., and one or more of them can be selected by those skilled in the art for compounding according to the needs;

the aggregate adopted in the embodiment of the invention is also conventional aggregate, such as natural sand, machine-made sand, light aggregate and the like, the light aggregate can be expanded perlite, vitrified micro bubbles, hollow glass beads, foamed resin particles, expanded clay and the like, and one or more of the aggregates can be selected by a person skilled in the art to be proportioned according to actual needs.

when the wet mixture is adhered to one side or two sides of the plane of the support body, the wet mixture can be uniformly adhered to one side or two sides of the plane of the support body according to the use requirement, and the wet mixture can also be non-uniformly adhered to one side or two sides of the plane of the support body. The wet mix may present a structure of projections, grooves, etc. in the plane of the support, see in particular the relevant structure in patent CN 211441435U.

It is worth mentioning that the focus of the present invention is on the preparation process of the dry mortar in sheet form, and the form (including structure and distribution, etc.) of the wet mix on the plane of the support is not limited.

Step S30: and drying and hardening the wet sheet mortar in the step S20 to remove part or all of the solvent in the wet sheet mortar, thereby obtaining the sheet dry mortar.

It is understood that the solvent in the wet sheet-like mortar in step S30 can be removed by various methods, such as normal pressure drying, reduced pressure drying, microwave drying, and low temperature drying, and the solvent can be removed by any method. The invention is not limited to the solvent removal mode; in addition, during the actual production process, the solvent may be partially remained, that is, the solvent may not be removed 100% without significantly affecting the performance of the finally formed sheet-like dry mortar, and the situation is also within the protection scope of the present invention.

Finally, the wet mix on one or both sides of the plane of the support is converted into a dry mortar.

Optionally, the admixture may be added to the dry mixture to achieve at least one of the following objectives: saving inorganic cementing materials, improving the performance of the mortar and adjusting the strength of the mortar; for example, the admixture may be an active admixture and/or an inactive admixture, and specifically, the admixture may be at least one of fly ash, slag powder, silica fume, zeolite powder, desulfurized gypsum, limestone powder, steel slag powder, phosphorous slag powder, and the like.

Optionally, different additives, such as at least one of water retention agent, re-dispersible latex powder, early strength agent, retarder, accelerator, waterproof agent, water reducing agent, antifreeze, disintegrating agent, swelling agent, shrinkage reducing agent, etc., can be added to improve or realize various characteristics of the mortar, more specifically, the water retention agent is at least one of methyl cellulose, hydroxyethyl cellulose, carboxyethyl methyl cellulose, hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, etc.; the redispersible latex powder is at least one of ethylene-vinyl acetate copolymer, ethylene-vinyl chloride-vinyl laurate terpolymer, vinyl acetate-ethylene-higher fatty acid vinyl ester terpolymer, vinyl acetate-acrylate-higher fatty acid vinyl ester terpolymer and the like; the early strength agent is at least one of chloride, sulfate, carbonate, nitrate, nitrite, sodium silicate, triethanolamine, triisopropanolamine, calcium formate, sodium acetate and the like; the retarder is at least one of monosaccharide, polysaccharide, hydroxycarboxylic acid and salts thereof, polyalcohol and derivatives thereof, organic phosphoric acid and salts thereof, phosphate, zinc salt, boric acid and salts thereof, fluorosilicate and the like; the accelerating agent is at least one of sodium aluminate, potassium aluminate, sodium carbonate, potassium carbonate, water glass, low-alkali or alkali-free accelerating agent and the like; the waterproof agent is at least one of chloride salt, aluminum salt, silicate, stearate, organic silicon, metal soap, rubber emulsion, resin emulsion and the like; the water reducing agent is at least one of a polycarboxylic acid water reducing agent, a naphthalene water reducing agent, an anthracene water reducing agent, an amino sulfonate, an aliphatic hydroxy sulfonate, melamine, lignosulfonate, humic acid and the like; the antifreezing agent is at least one of nitrite, chloride salt, formamide, calcium oxalate, sodium acetate and the like; the disintegrating agent is at least one of microcrystalline cellulose, low-substituted hydroxypropyl cellulose, carboxymethyl cellulose calcium, sodium carboxymethyl starch, hydroxypropyl distarch phosphate, copovidone, alginate and the like; the expanding agent is at least one of calcium sulphoaluminate, magnesium oxide, calcium oxide, ferric oxide and the like; the shrinkage reducing agent is at least one of monohydric alcohol, dihydric alcohol, amino alcohol, polyoxyethylene, polyether and the like.

Optionally, in order to improve the crack resistance of the mortar, fibers are added into the dry mixture, for example, the fibers can be at least one of carbon fibers, glass fibers, steel fibers, polymer fibers and the like; more specifically, the polymer fiber is at least one of polyamide fiber, polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polyester fiber, aramid fiber, spandex fiber, and the like.

Different dry mixtures can be selected for adding and combining according to the specific application environment of the mortar, and the like, and the components of the dry mixture in the embodiment of the invention can meet the following conditions: the dry mixture comprises the following components in parts by weight: 15-70 parts of inorganic cementing material, 15-85 parts of aggregate, 0-25 parts of admixture, 0-6 parts of additive and 0-5 parts of fiber; preferably, the fiber-reinforced composite material comprises 20-50 parts of inorganic cementing materials, 35-75 parts of aggregates, 0-15 parts of admixtures, 0-4 parts of additives and 0-3 parts of fibers.

In order to inhibit the hydration reaction between the inorganic cementing material and water in the preparation process of the sheet-shaped dry mortar, the solvent can only comprise an organic solvent, or the solvent comprises the organic solvent and water, wherein the weight ratio of the organic solvent to the water is 1 (0-7), preferably 1 (0-4).

In order to fully dissolve the water-soluble binder and ensure that the glue solution has proper fluidity, the weight ratio of the water-soluble binder to the solvent in the glue solution is 1 (1-35), preferably 1 (3-25). Through the proportion, the water-soluble binder can be decomposed into a small molecular state from a particle state, so that the water-soluble binder has better diffusion capacity in the particle gaps of the dry mixture, a sufficiently dense binder network can be formed, and the finally formed flaky dry mortar has higher strength.

The water-soluble binder adopted by the embodiment of the invention is at least one of vegetable gum, animal gum, microbial gum, modified cellulose, polymeric water-soluble resin and condensed water-soluble resin; preferably, the water-soluble binder is at least one of natural starch, seaweed gel and modified starch. More specifically, the natural starch is at least one of wheat starch, potato starch, sweet potato starch, rice flour starch and the like; the vegetable gum is at least one of acacia gum, guar gum, locust bean gum, soybean gum, seaweed gum and the like; the seaweed gel is at least one of sodium alginate, agar, seaweed polysaccharide, agar, carrageenan and the like; the animal glue is at least one of bone glue, gelatin, casein, hyaluronic acid and the like; the microbial gum is at least one of xanthan gum, glucan, polyglutamic acid, guar gum and the like; the modified cellulose is at least one of hydroxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxymethyl ethyl cellulose, etc.; the modified starch is at least one of hydroxymethyl starch, hydroxyethyl starch, cyanoethyl starch, acetic acid starch, cationic starch, polymeric starch and the like; the polymeric water-soluble resin is at least one of polyacrylamide, polyvinyl formamide, polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, polymaleic anhydride, polydimethyldiallylammonium chloride, copolymers of the above polymers and the like; the condensed water-soluble resin is at least one of polyamine, quaternary ammonium salt polymer, amino resin, alkyd resin, polyurethane resin and the like.

Further, the weight ratio of the dry mixture to the glue solution in the step S10 is 100 (6-30), preferably 100 (8-25). Therefore, the dry mixture can be fully wetted by the glue solution, so as to further ensure that the finally formed sheet-shaped dry mortar has enough strength.

Further, the support is at least one of an inorganic fiber mesh, a polymer mesh, a metal mesh, or a soluble film. The support body can improve the breaking strength of the sheet-shaped dry mortar, and even if the sheet-shaped dry mortar is broken, the dry mortar on the surface of the support body cannot be separated from the support body and fall off, so that the 'breaking and continuous' effect is realized. Meanwhile, water can permeate from one side of the support body to the other side, so that when water is sprayed on the sheet-shaped dry mortar, the water can rapidly permeate through the support body, so that the mortar on the surface of the support body is rapidly dispersed to form wet slurry.

Optionally, the invention also provides the sheet-shaped dry mortar prepared by the preparation process.

In the following, some specific examples and comparative examples are listed to verify the feasibility and beneficial effects of the preparation process of the present invention, which are intended to clearly understand the spirit of the present invention, but should not be construed as limiting the scope of the present invention in any way. In the following examples and comparative examples, each raw material was obtained commercially.

The performance test of the samples of each example and comparative example listed below includes four dimensions: the test method comprises the following steps of breaking load, dissolving time limit, 28d compressive strength after hardening and 14d tensile bonding strength:

the method for testing the breaking load comprises the following steps:

taking 3 cylindrical metal rods (the length is 100mm, the diameter of the cross section circle is 10mm) made of the same material, wherein two cylindrical metal rods are placed at the bottom of a square sheet-shaped dry mortar sample (the side length is 100mm) and fixed, the other cylindrical metal rod is placed at the upper part of the sheet-shaped dry mortar sample, and the placement positions are shown in figures 2 and 3. A vertically downward load was uniformly applied to the upper cylindrical metal bar using a pressure gauge, and the breaking load of the test sample, which is the reading of the pressure gauge when the sheet-like dry mortar breaks + the weight of the upper metal bar, was in newtons (N).

The dissolution time limit test method is as follows:

750ml of water is contained in a 1000ml beaker, the water temperature is 20 +/-5 ℃, a magnetic stirrer is placed in the beaker, a square hole screen with the aperture of 5.5mm is horizontally arranged at the 500ml scale in the beaker, and the square hole screen is tightly clamped with the inner wall of the beaker. The beaker was placed on a magnetic stirrer with a speed set at 500 rpm. The test specimens were of a cubic dry mortar with sides of 30mm by 3mm and were dried for 24 hours at 60 ℃ before testing. The sample is gently placed into a beaker, a stopwatch is started to time, the slurry to be dissolved completely penetrates through the square-hole screen (wherein the support, the fibers and the large-particle aggregate can not pass through the square-hole screen), the time is stopped, and the recorded time is the dissolution time limit of the test sample and is the unit of seconds(s).

The 28d compressive strength and the 14d tensile bond strength after hardening are determined according to the standard of JGJ/T70-2009 basic performance test method for building mortar. During measurement, the sheet-like dry mortar is crushed in advance, the support body is removed, and then the sheet-like dry mortar is mixed with water and dissolved into slurry with the consistency of 85mm-90 mm.

Example 1

A preparation process of flaky dry mortar comprises the following steps:

wherein the dry mixture is prepared by mixing 20 parts by weight of cement, 70 parts by weight of river sand, 6 parts by weight of fly ash, 3 parts by weight of ethylene-vinyl acetate copolymer rubber powder, 0.1 part by weight of hydroxypropyl methyl cellulose and 0.9 part by weight of glass fiber, and the diameter of the glass fiber is 0.3 mm; the glue solution is obtained by dissolving 1.0 part by weight of polyvinyl alcohol in 14 parts by weight of methanol aqueous solution solvent, wherein the weight parts of methanol to water is 90: 10;

step S20: uniformly coating the wet mixed material in the step S10 on two sides of the plane of the glass fiber mesh cloth to obtain wet sheet mortar with the thickness of 3 mm;

step S30: and (4) drying the wet sheet mortar in the step S20 for 2 hours at 75 ℃, removing the solvent, and solidifying and hardening the wet sheet mortar to obtain the sheet dry mortar.

Example 2

A preparation process of flaky dry mortar comprises the following steps:

the dry mixture is prepared by mixing 45 parts by weight of cement, 5 parts by weight of lime, 28 parts by weight of river sand, 7 parts by weight of expanded perlite, 10 parts by weight of desulfurized gypsum, 4 parts by weight of vinyl acetate-ethylene-higher fatty acid vinyl ester terpolymer rubber powder, 0.3 part by weight of methyl cellulose and 0.7 part by weight of polypropylene fiber, wherein the diameter of the polypropylene fiber is 0.3 mm; the glue solution is obtained by dissolving 0.9 weight part of polyethylene glycol in 15 weight parts of ethanol aqueous solution solvent, wherein the average molecular weight of the polyethylene glycol is 6000, and the weight parts of ethanol and water in the ethanol aqueous solution are 95: 5;

step S20: uniformly coating the wet mixed material in the step S10 on two sides of the plane of the polyester fiber mesh cloth to obtain wet sheet mortar with the thickness of 3 mm;

step S30: and (5) drying the wet sheet mortar in the step S20 for 2.5 hours at the temperature of 80 ℃, removing the solvent, and solidifying and hardening the wet sheet mortar to obtain the sheet dry mortar.

Example 3

A preparation process of flaky dry mortar comprises the following steps:

the dry mixture is prepared by mixing 26 parts by weight of cement, 5 parts by weight of lime, 55 parts by weight of river sand, 5 parts by weight of vitrified micro bubbles, 4 parts by weight of slag powder, 3.8 parts by weight of ethylene-vinyl acetate copolymer rubber powder, 0.2 part by weight of carboxyethyl methyl cellulose, 0.1 part by weight of polycarboxylic acid water reducing agent, 0.4 part by weight of calcium chloride and 0.5 part by weight of polyamide fiber, wherein the diameter of the polyamide fiber is 0.3 mm; the gum solution is obtained by dissolving 1.8 parts by weight of xanthan gum in 15 parts by weight of methanol solvent;

Example 4

A preparation process of flaky dry mortar comprises the following steps:

the dry mixture is prepared by mixing 16 parts by weight of cement, 70 parts by weight of river sand, 5 parts by weight of vitrified micro bubbles, 4 parts by weight of fly ash, 3.5 parts by weight of ethylene-vinyl acetate copolymer rubber powder, 0.3 part by weight of hydroxypropyl methyl cellulose, 0.1 part by weight of polycarboxylic acid water reducing agent, 0.6 part by weight of sodium sulfate and 0.5 part by weight of polyamide fiber, wherein the diameter of the polyamide fiber is 0.3 mm; the glue solution is obtained by dissolving 1.3 parts by weight of polyethylene oxide in 15 parts by weight of acetonitrile solvent;

step S30: and (4) drying the wet sheet mortar in the step S20 for 2 hours at 85 ℃, removing the solvent, and solidifying and hardening the wet sheet mortar to obtain the sheet dry mortar.

Example 5

A preparation process of flaky dry mortar comprises the following steps:

wherein the dry mixture is obtained by mixing 35 parts by weight of cement and 65 parts by weight of river sand; the glue solution is obtained by dissolving 1.2 parts by weight of polyethylene glycol in 15 parts by weight of ethanol aqueous solution solvent, wherein the average molecular weight of the polyethylene glycol is 6000, and the weight parts of ethanol and water in the ethanol aqueous solution are 85: 15;

Comparative example 1

The difference from the example 2 is only that the dry mixture comprises the following components in parts by weight: 55 parts of cement, 16 parts of lime, 8 parts of expanded perlite, 16 parts of desulfurized gypsum, 4 parts of vinyl acetate-ethylene-higher fatty acid vinyl ester terpolymer rubber powder, 0.3 part of methyl cellulose and 0.7 part of polypropylene fiber;

comparative example 2

The difference from the example 2 is only that the dry mixture comprises the following components in parts by weight: 10 parts of cement, 1 part of lime, 86 parts of river sand, 2 parts of vinyl acetate-ethylene-higher fatty acid vinyl ester terpolymer rubber powder, 0.3 part of methyl cellulose and 0.7 part of polypropylene fiber.

Comparative example 3

The difference from example 2 is only that the amount of the polyethylene glycol is 0.15 parts by weight.

Comparative example 4

The same composition as that of example 2, except that the preparation process by hot melt method: mixing the dry mixture with polyethylene glycol, placing the mixture in a mold, and paving polyester fiber mesh cloth in the powder. Heating the materials to 90 ℃, applying certain pressure, preserving heat for 30 minutes, cooling, and hardening and forming to obtain the flaky dry mortar with the thickness of 3 mm.

Comparative example 5

The only difference from example 2 is that the polyethylene glycol was premixed with the dry blend and then mixed with the aqueous ethanol solution.

The sheet-like dry mortars obtained in the above examples and comparative examples were measured for breaking load, time limit of dissolution, 28d compressive strength and 14d tensile bond strength after hardening, and the test results are shown in Table 1.

TABLE 1 Performance test results of the samples of each example and comparative example

As can be seen from the above table, although comparative examples 1 to 3 prepared the sheet-like dry mortar by the preparation method of the present invention, the mixing amounts of the respective components are not within the claimed scope of the present invention, the sheet-like dry mortar prepared by comparative examples 1 to 3 has a reduced performance compared to examples 1 to 5;

in contrast, in comparative example 4, in which the hot-melt molding method (e.g., comparative example 4) was used, the sheet-like dry mortar prepared in comparative example 4 was greatly reduced in breaking load and dissolution time, as compared with the preparation process according to the present invention.

In the comparative example 5, the water-soluble binder and the dry mortar mixture are mixed in advance and then dissolved in the solvent, so that the sheet-shaped dry mortar prepared in the comparative example 5 has a great reduction in breaking load and dissolution time compared with the preparation process adopted by the invention. The reason for this is that if the water-soluble binder is mixed with the dry mortar mixture in advance and then dissolved in the solvent, the diffusion capability of the water-soluble binder in the gaps between the particles of the dry mixture is weakened, and the density of the binder network is reduced, thereby weakening the strength of the finally formed sheet-like dry mortar and prolonging the dissolution time limit.

In examples 1 to 5, however, dry mortars in sheet form were prepared according to the claimed process, all having a good overall performance.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A preparation process of flaky dry mortar is characterized by comprising the following steps:

wherein the dry mixture is at least obtained by mixing inorganic cementing materials and aggregates; the glue solution is obtained by dissolving a water-soluble binder in a solvent;

the solvent comprises an organic solvent, or the solvent comprises an organic solvent and water;

the weight ratio of the water-soluble binder to the solvent in the glue solution is 1 (1-35);

the weight ratio of the dry mixture to the glue solution in the step S10 is 100 (6-30).

2. The process for preparing a flaky dry mortar according to claim 1, wherein the dry mixture is obtained by mixing at least one of admixtures, additives and fibers with inorganic gelling materials and aggregates.

3. The preparation process of the flaky dry mortar according to claim 2, wherein the admixture is at least one of fly ash, slag powder, silica fume, zeolite powder, desulfurized gypsum, limestone powder, steel slag powder and phosphorous slag powder; the additive is at least one of water-retaining agent, redispersible latex powder, early strength agent, retarder, accelerator, waterproofing agent, water reducing agent, antifreezing agent, disintegrating agent, expanding agent and shrinkage reducing agent; the fibers are at least one of carbon fibers, glass fibers, steel fibers and polymer fibers.

4. The preparation process of the flaky dry mortar according to claim 1 or 2, wherein the dry mortar comprises the following components in parts by weight: 15-70 parts of inorganic cementing material, 15-85 parts of aggregate, 0-25 parts of admixture, 0-6 parts of additive and 0-5 parts of fiber.

5. The process for preparing the flaky dry mortar of claim 4, which comprises 20 to 50 parts of inorganic cementing material, 35 to 75 parts of aggregate, 0 to 15 parts of admixture, 0 to 4 parts of additive and 0 to 3 parts of fiber.

6. The process for preparing sheet-like dry mortar according to claim 1, wherein when the solvent comprises an organic solvent and water, the weight ratio of the organic solvent to the water is 1 (0-7).

7. The process for preparing sheet-like dry mortar according to claim 6, wherein the weight ratio of the organic solvent to the water is 1 (0-4).

8. The preparation process of the flaky dry mortar according to claim 1, wherein the weight ratio of the water-soluble binder to the solvent in the glue solution is 1 (3-25).

9. The process for preparing sheet-like dry mortar according to claim 1, wherein the water-soluble binder is at least one of vegetable gum, animal gum, microbial gum, modified cellulose, polymeric water-soluble resin, and condensed water-soluble resin.

10. The process for preparing the flaky dry mortar of claim 1, wherein the water-soluble binder is at least one of natural starch, seaweed glue and modified starch.

11. The preparation process of the flaky dry mortar of claim 1, wherein the weight ratio of the dry mixture to the glue solution in the step S10 is 100 (8-25).

12. The process for preparing a sheet-like dry mortar according to claim 1, wherein the support is at least one of an inorganic fiber mesh, a polymer mesh, a metal mesh or a soluble film.

13. A dry mortar in sheet form prepared by a process for its preparation according to any one of claims 1 to 12.