CN102219550B - Stone paper for maintaining cement mortar and preparation method thereof - Google Patents

Abstract

The invention provides stone paper for maintaining cement mortar and a preparation method thereof. The stone paper for maintaining the cement mortar comprises the following components in part by weight: 45 to 65 parts of heavy calcium carbonate, 10 to 30 parts of active silica micropowder, 0.1 to 0.3 part of triphenyl phosphate, 3 to 5 parts of silane coupling agent, 20 to 30 parts of linear low-density polyethylene and 5 to 10 parts of hot melt adhesive. In the stone paper, the surface of concrete is directly covered by a macromolecular polymer serving as a basic material after pouring concrete in an acid mode; and the stone paper and the surface of the mortar are subjected to crosslinking adsorption to form one layer of protective film, so that rapid evaporation of water on the surface of the concrete is controlled and plastic shrinking cracking is prevented.

Description

Stone paper for cement mortar maintenance and preparation method thereof

technical field

The present invention relates to a building material.

Background technique

China's economy is in a stage of rapid development, and my country's highways, large-scale engineering construction, especially metropolitan subway engineering construction are also booming, and are now at the forefront of the world. In the process of large-scale projects, there are also some technical problems to be solved, such as the cracking problem of the surface after concrete pouring, the cracking problem and deformation resistance of the subgrade surface after expressway concrete pouring; the freezing and thawing resistance required for construction in severe cold areas Questions and more. To overcome technical difficulties, we must rely on scientific and technological progress and adopt advanced technologies, including the application of new materials.

Hot weather usually causes plastic shrinkage and cracking of concrete. If the surrounding environment causes rapid evaporation of moisture on the concrete surface, plastic shrinkage cracking will also occur at any time. Once the evaporated water on the concrete surface is greater than the bleeding speed, cracking will occur, because this makes the surface appear rapid. Drying shrinkage and tensile stress produce irregularly shaped cracks. Plastic shrinkage cracks sometimes appear on the surface shortly after the fresh concrete is poured, and sometimes they occur during or shortly after finishing. Taking preventive measures, such as regular watering on the mortar surface, covering plastic film, planting grass, etc., can reduce the cracks that mainly appear on the horizontal surface, but it takes a lot of manpower and material resources, especially for large-scale projects. There are certain difficulties.

Contents of the invention

The object of the present invention is to provide a kind of stone paper used for cement mortar maintenance and its preparation method, to overcome the above-mentioned defects existing in the prior art.

The stone paper used for cement mortar maintenance includes the following components by weight:

The ground calcium carbonate calcite powder has a fineness of 1500-2000 mesh;

Main indicators of silica powder: SiO ₂ content 83-96%, average particle size 0.15-0.335um, specific surface area 15-22m ² /g, pozzolanic activity index> 86%, natural bulk density 180-240kg/m ³ ;

The alkane coupling agent is r-methacryloxypropyltrimethoxysilane;

The trade name of the linear low density polyethylene is LLDPE, the density is 0.92-0.93, the melt index MI0.3-0.6, preferably bimodal;

The hot melt adhesive is ethylene-vinyl acetate copolymer, referred to as EVA, with a melting point of 85-105°C;

Further, include the following components:

The fineness of the bentonite is 1200-1500 mesh;

The modified polyethylene wax is polyamide-modified polyethylene micronized wax, which is a product of 9615A from Clariant;

The preparation method of the described stone paper that is used for cement mortar maintenance, comprises the steps:

Mix heavy calcium carbon, activated silica micropowder, triphenyl phosphite and silane coupling agent at 130-150°C for 30-60 minutes, then add linear low-density polyethylene, hot melt adhesive, stearic acid , Epoxy dioctyl tetrahydrophthalate, modified polyethylene wax, bentonite, oleic acid amide and sorbitan stearate, mixed for 30-60 minutes, and then sent to a plasticizer at 170-185°C Plasticizing, 175～185℃ extruder casting, 170～185℃ four-axis calender rolling into? 0.10-0.12mm stone paper, after cooling down, then equilibrate for 25-30 minutes under the conditions of 25±2°C and relative humidity of 60±2%, and then the product can be obtained.

The stone paper maintained by cement mortar of the present invention uses high-molecular polymer as the base material, carries out compound modification on calcium carbonate and active silica micropowder, and adds other additives, utilizes the principle of high-molecular interface chemistry and high-molecular modification Features: After special processing, it is made by polymer mixing, filler compound modification, polymer and filler plasticization, extrusion casting, and calendering. After the concrete is poured, the acid is directly covered on the surface of the concrete. Using the principle of bentonite in the stone paper to absorb water and expand, and the active silica powder in the stone paper under the action of the silane coupling agent, it is cross-linked and adsorbed on the surface of the mortar to form a layer of protection. Membrane to control the rapid evaporation of moisture on the concrete surface and prevent plastic shrinkage cracking.

Detailed ways

In the examples, unless otherwise specified, all are parts by weight.

Example 1

65 parts of heavy calcium carbonate, 10 parts of active silica powder, 0.1 part of triphenyl phosphite, 3 parts of silane coupling agent, 30 parts of linear low density polyethylene, 5 parts of hot melt adhesive, 2,2-bis( 0.3 parts of 4-hydroxyphenyl)propane, 0.5 parts of stearic acid, 0.5 parts of dioctyl epoxy tetrahydrophthalate, 0.2 parts of modified polyethylene wax, 0.5 parts of bentonite, 0.3 parts of oleic acid amide, dehydration 0.5 parts of sorbitol stearate.

Preparation:

Mix heavy calcium carbonate, activated silica micropowder, triphenyl phosphite, silane coupling agent at 130°C for 60 minutes, then add linear low density polyethylene, hot melt adhesive, stearic acid, epoxy four Dioctyl hydrogen phthalate, modified high-density polyethylene wax, bentonite, oleic acid amide, and sorbitan stearate continued to mix for 30 minutes, then sent to a plasticizing machine at 170°C for plasticization, and extruded at 170°C Out of the machine, the four-axis calender is calendered at 170°C to form a stone paper of about 0.12mm. After cooling down, it is then equilibrated at 25±2°C and relative humidity of 60±2% for 25 minutes to obtain the product.

Example 2

55 parts of heavy calcium carbonate, 20 parts of active silica powder, 0.2 parts of triphenyl phosphite, 4 parts of silane coupling agent, 20 parts of linear low density polyethylene, 10 parts of hot melt adhesive, 2,2-bis( 0.4 parts of 4-hydroxyphenyl)propane, 1 part of stearic acid, 1 part of epoxy tetrahydrophthalate dioctyl, 0.3 parts of modified polyethylene wax, 1 part of bentonite, 0.4 parts of oleic acid amide, dehydration 0.75 parts of sorbitol stearate. .

Preparation:

Mix heavy calcium carbon, active silica powder, triphenyl phosphite, silane coupling agent at 140°C for 45 minutes, then add linear low density polyethylene, hot melt adhesive, stearic acid, epoxy tetra Dioctyl hydrogen phthalate, modified polyethylene wax, bentonite, oleic acid amide, and sorbitan stearate continued to mix for 45 minutes, then sent to a plasticizing machine at 173°C for plasticization, and extruder at 175°C Casting, 175°C four-axis calender calendering into stone paper of about 0.12mm, after cooling down, then equilibrate at 25±2°C, relative humidity 60±2% for 30 minutes, then roll and pack.

Example 3

45 parts of heavy calcium carbonate, 30 parts of active silica powder, 0.3 parts of triphenyl phosphite, 5 parts of silane coupling agent, 25 parts of linear low density polyethylene, 8 parts of hot melt adhesive, 2,2-bis( 0.5 parts of 4-hydroxyphenyl) propane, 1.5 parts of stearic acid, 1.5 parts of dioctyl epoxy tetrahydrophthalate, 0.4 parts of modified polyethylene wax, 1.5 parts of bentonite, 0.5 parts of oleic acid amide, dehydration 1 part of sorbitan stearate.

Preparation:

Mix heavy calcium carbonate, activated silica micropowder, triphenyl phosphite, silane coupling agent at 150°C for 30 minutes, then add linear low density polyethylene, hot melt adhesive, stearic acid, epoxy four Dioctyl hydrogen phthalate, modified polyethylene wax, bentonite, oleic acid amide, and sorbitan stearate continued to mix for 60 minutes, then sent to a plasticizing machine at 176°C for plasticization, and extruder at 179°C Casting, 180°C four-axis calender calendering into stone paper of about 0.11mm, after cooling down, then equilibrate at 25±2°C, relative humidity 60±2% for 25 minutes, then roll and pack.

Example 4

60 parts of heavy calcium carbonate, 15 parts of active silica powder, 0.1 part of triphenyl phosphite, 3 parts of silane coupling agent, 22 parts of linear low density polyethylene, 10 parts of hot melt adhesive, 2,2-bis( 0.6 parts of 4-hydroxyphenyl) propane, 0.5 parts of stearic acid, 1.5 parts of dioctyl epoxy tetrahydrophthalate, 0.5 parts of modified polyethylene wax, 1.5 parts of bentonite, 0.6 parts of oleic acid amide, dehydration 0.75 parts of sorbitol stearate. .

Preparation:

Mix heavy calcium carbonate, activated silica micropowder, triphenyl phosphite, silane coupling agent at 135°C for 30 minutes, then add linear low density polyethylene, hot melt adhesive, stearic acid, epoxy four Dioctyl hydrogen phthalate, modified polyethylene wax, bentonite, oleic acid amide, and sorbitan stearate continued to mix for 60 minutes, and then sent to a 180°C plasticizing machine for plasticization, and a 180°C extruder Casting, 180°C four-axis calender calendering into stone paper of about 0.12mm, after cooling down, then balance at 25±2°C, relative humidity 60±2% for 30 minutes, then roll and pack.

Example 5

50 parts of heavy calcium carbonate, 25 parts of active silica powder, 0.2 part of triphenyl phosphite, 4 parts of silane coupling agent, 28 parts of linear low density polyethylene, 7 parts of hot melt adhesive, 2,2-bis( 0.5 parts of 4-hydroxyphenyl)propane, 1 part of stearic acid, 1 part of epoxy tetrahydrophthalate dioctyl, 0.6 parts of modified polyethylene wax, 1 part of bentonite, 0.4 parts of oleic acid amide, dehydration 0.6 parts of sorbitol stearate.

Preparation:

Mix heavy calcium carbon, active silica powder, triphenyl phosphite, silane coupling agent at 145°C for 45 minutes, then add linear low density polyethylene, hot melt adhesive, stearic acid, epoxy tetra Dioctyl hydrogen phthalate, modified polyethylene wax, bentonite, oleic acid amide, and sorbitan stearate continued to mix for 45 minutes, and then sent to a plasticizing machine at 185°C for plasticization, and extruder at 180°C Casting, calendering at 185°C with a four-axis calender to form stone paper of about 0.10mm, after cooling down, then balance at 25±2°C and relative humidity of 60±2% for 25 minutes, then roll and pack.

Example 6

50 parts of heavy calcium carbonate, 25 parts of active silica powder, 0.3 parts of triphenyl phosphite, 5 parts of silane coupling agent, 24 parts of linear low density polyethylene, 9 parts of hot melt adhesive, 2,2-bis( 0.5 parts of 4-hydroxyphenyl)propane, 1.5 parts of stearic acid, 1.5 parts of dioctyl epoxy tetrahydrophthalate, 0.4 parts of modified polyethylene wax, 1.5 parts of bentonite, 0.4 parts of oleic acid amide, dehydration 0.9 part of sorbitol stearate.

Preparation:

Mix heavy calcium carbon, activated silica powder, triphenyl phosphite, and silane coupling agent at 140°C for 60 minutes, then add linear low-density polyethylene, hot melt adhesive, stearic acid, and epoxy tetra Dioctyl hydrogen phthalate, modified polyethylene wax, bentonite, oleic acid amide, and sorbitan stearate continued to mix for 30 minutes, then sent to a plasticizing machine at 180°C for plasticization, and extruder at 182°C Casting, 185°C four-axis calender calenders into stone paper of about 0.10mm, after cooling down, then balance at 25±2°C, relative humidity 60±2% for 30 minutes, then roll and pack.

Application Example 7

At present, there is no national or industry standard for concrete curing paper, and the actual measurement of the examples can only be carried out according to the commonly used test methods for paper. For the detection methods used, please refer to the relevant standards: GBT 13023-2008 corrugated (base paper), QBT3805-1999 poly Vinyl chloride wallpaper, JGJ 70-2009 building mortar basic performance test method, the results are shown in Table 1 and Table 2.

Table I

Application test: large-scale square pouring concrete is the object, and the time is mid-April, sunny, and the ambient temperature is 18-24°C: 30 minutes after the large-scale square concrete is poured, the curing paper of the present invention is immediately covered on the concrete surface, and compared 1 is covering concrete with plant grass; comparison 2 is open-air concrete; by measuring the concrete surface:

Table II

From the practical application, it can be concluded that the concrete cured with curing stone paper only needs to be watered once within 48 hours, and the surface is smooth without cracks after 6 months. However, the concrete covered with plant grass was watered three times in 48 hours, and the concrete in the open air was watered four times in 48 hours. After 28 days, slight cracks still appeared. At the same time, the use of plant grass also required manual cleaning of the site, which was time-consuming and labor-intensive. ; The open air still needs to be watered one more time and the expected effect has not yet been achieved. It is shown from the application test that the cement slurry curing stone paper of the present invention has achieved the desired effect.

Claims (1)

1. be used for the stone paper of maintaining cement mortar, it is characterized in that, formed by the component of following weight part: