CN85104528A - Sprayable plastics - Google Patents

Abstract

By adding at least a hydroxypropyl Natvosol improvement to realize to spray interior wall plaster as a water retention aid or thickening material with specific substitution level.

Description

Sprayable plastics

The present invention relates to contain novel compositions at least a hydroxypropyl Natvosol, that be used for to spray wall usefulness plaster.

(chemical molecular formula is CaSO to the gypsum of nature ₄2H ₂O) all exploited in many places.With known method this natural product is changed into calcium sulfate hemihydrate, this generally is called plaster of Paris.Commercial available plaster of Paris qualitatively, alters a great deal with the different of method in order to processing and manufacturing according to the place of production on the purity with on the performance.

Plaster of Paris is widely used as one of raw material in making the gypsification compound, this gypsification compound or with cutter or similar tool or be applied to spraying method on the suitable position of buildings or other structure such as wall and ceiling.

Conventional Sprayable plastics or be sometimes referred to as the mixtures of thickening agents of spraying the control rheology that plaster is plaster of Paris and less share and keeping moisture content.Plaster of Paris can contain calcium hydroxide selectively.It also contains a spot of modified starch sometimes, and the multipolymer of polyacrylamide or a kind of acrylamide is with further water-retentivity and the spray characteristic of improving.Also have a small amount of aerating additive in addition, for example also can mix sodium lauryl sulphate.

The stucco blend of doing in specific mixing device, is mixed with water simply, and with air spraying to inner wall surface.When The cross the grey pug that has sprayed smeared with cutter and carefully smear into several procedures of smooth surface after, this surface is paintable or use wallpaper decoration.

A kind of curing of routine the physical property of plaster can determine that also the speed of promptly removing from plaster by water in solidification process is determined with solidified speed.Can both make the physical deterioration of plaster by what increase to remove water speed or reduce water concentration that curing reaction begins to any influence of these parameters.If plaster is done too soon, then each layer of the plaster of smearing and retouching with cutter also is subjected to injurious effects.Most of levels that these plaster was coated with are porous on wallboard, Slag building block or masonry for example, these difficult points that just can cause just being mentioned.

In order to overcome or to make the problem of above-mentioned dehydration reduce to minimum at least, in mortar composition, add the polymkeric substance of small amounts of water soluble, resemble Natvosol, methyl hydroxyethylcellulose and methylhydroxypropylcellulose, as water retention aid.These polymkeric substance are expected the time to make plaster absorb high moisture content in beginning, and to substrate, it is for the viscosity that increases the stucco blend water that this polymkeric substance is used in the plaster to anti-again then sealing from the plaster ease.Therefore, desired is that water concentration in plaster is maintained in solidification process.In addition, it is former in to be stabilized in the high air content in the plaster to add these polymkeric substance, thereby can obtain slick retouching.Yet above-mentioned water-soluble polymers does not often provide or keeps water concentration and the air content in the plaster of residence not hoping, so that plaster has more bad spray characteristics and workability.It is often uneven when as a result, the plaster that contains above-mentioned thickening material is coated onto on the metope; The retouching of doing too fast and at last is bad.

Also have the another one method to be exactly, the so impure water-soluble cellulose ether of methyl hydroxypropyl Natvosol and hydroxypropyl Natvosol for example, it is to obtain like this: Mierocrystalline cellulose of crossing with the metal hydroxides alkalinisation treatment and suitable reagent react, then with the reaction mixture neutralization (this sour an alkali metal salt for calcium sulfate plaster have delayed coagulation) of acid to the ether of cellulose of gained, therefore form metal-salt on the spot, its ether of cellulose (was seen United States Patent (USP) 3 from about 20: 1 to the weight ratio of an alkali metal salt within about 1: 1 scope, as if fail to draw desired result when 936,313) this calcium sulfate plaster additive composition joins among the calcium sulfate plaster.

The invention provides the plaster that can spray, its composition is: from about 99.95% to about 99% plaster of Paris, from about 0.05% to about 1% water-retentivity thickening material, when mixing, this water-retentivity thickening material thinks about 25% during of itself weight to about 60% water, formation can be sprayed onto lamellar plaster on the substrate, it is characterized in that: water-retaining admixture is a kind of hydroxypropyl Natvosol at least, it have hydroxyethyl replace be about 0.3 to about 0.4MS and the hydroxypropyl replacement greater than 0.35MS, and have and be equal to or less than 5% ash content.Hydroxypropyl replaces to be preferably and is at least 0.6MS, and is best, and the MS of hydroxyethyl approximately from 0.7 to 1.8, and the MS of hydroxypropyl, from about 0.6 to about 1.2.The MS altogether of these two substituted radicals should be able to provide and has high Brooker Fei Erde viscosity.The hydroxypropyl Natvosol of (Brookfield viscosity), just this viscosity is at least 100 centipoises (CPS) in 23 ℃ 1% aqueous solution, and being preferably in 1% aqueous solution is 2000 to about 4000 centipoises.Total MS from about 1.0 to about 5.0 of general these two kinds of substituted radicals.

" MS " this title is meant the average mol with every Mierocrystalline cellulose anhydroglucose unit bonded hydroxyethyl or hydroxypropyl substituted radical.

The granular size of hydroxypropyl Natvosol also is important, has the hydroxypropyl Natvosol that fine granularity distributes because if use, and then can obtain best result.Distribution of particle sizes is that from about 85% to about 95% particle is by 140 purpose sieves preferably.A kind of so fine grain hydroxypropyl Natvosol makes polymkeric substance be dissolved in water rapidly, thereby guarantees the water uptake height, viscosity develop rapidly and in wet mortar water-retentivity good.This point is satisfactory, because use the mixing time that only allows weak point in the Sprayable plastics device at great majority.

When comparing as the plaster that sprays of water-holding agent preparation with known derivatived cellulose always, Sprayable plastics of the present invention is in texture, slickness, easily the carrying secretly of retouching property, air, open time, the smearing property of taking the photograph water and cutter all improves, and these all are the important references that is used for characterizing Sprayable plastics technically widely.They also demonstrate improved spray property and have low water loss.

The hydroxypropyl Natvosol that can be used for doing thickening material in plaster of the present invention is made with the Mierocrystalline cellulose effect by ethylene oxide and propylene oxide in a kind of highly basic medium.For the special process of implementing etherificate is a known technology, can use any currently known methods.

In the selection way, Natvosol can be used the propylene oxide etherificate in a strongly basic medium.In this case, Natvosol can be in fact any grade with MS from 0.3 to about 4.0.Material is during at 23 ℃, to have Brooker Fei Erde viscosity (Brookfield Viscosity) from 100 materials to about 5000 centipoises at 1% aqueous solution preferably.Higher or more low viscous material also can advantageously be used.

No matter the method for preparing hydroxypropyl Natvosol of the present invention how, this product neutralizes with acid, preferably nitric acid or for example mixing acid of nitric acid and acetic acid, then with the aqueous acetone solution washing that contains about 90% acetone, to remove byproduct of reaction, an alkali metal salt for example, ethylene glycol and propylene glycol, so, the ash oontent of final purification product is 5% or littler.Best, the ash content of product is 2.9 to 4.9%.If ash content surpasses 5%, then the hydroxypropyl Natvosol does not play thickening material or water retention aid in Sprayable plastics.

Any cellulosic furnish all can be used to prepare Natvosol, for example: the wood pulp of various viscosity, velveteen class and analogue.

Can make and only contain plaster and water retention aid of the present invention, be the Sprayable plastics of base with the plaster of Paris.In this case, the ratio of thickening material in plaster, typically should be do composition weight 0.05% to about 1%, preferably 0.1 to 0.2%.

In addition, plaster of Paris can contain calcium hydroxide and reaches 5%.

The dry plaster composition also can contain its amount of Rhoximat RH 148 (Hydroxy propyl guar) and be 0.01% to 1.0% of dry composition weight.The MS of Rhoximat RH 148 is preferably about 0.2 to about 0.6.

A spot of modified starch, the multipolymer of polyacrylamide or acrylamide, promptly about 1% of thickening material weight to about 30%, can be used to improve sag resistance, helps to absorb higher moisture content and the better bounding force of wet mortar to substrate is provided.

Also can add air, for example sodium lauryl sulphate and sodium stearate, its adding is to be 0.001% to about 1.0% of dry composition weight.

Therefore, dry plaster mixture of the present invention comprises: about 99.95% to about 99% plaster of Paris and about 0.05% to about 1% at least a hydroxypropyl Natvosol, preferably contains have an appointment 99.9% to about 99.8% plaster of Paris and about 0.1% to about 0.2% at least a hydroxypropyl Natvosol.

This dry plaster mixture forms a kind of plaster when adding entry, it can be sprayed onto on the substrate to 2 inch by every layer 1/4 inch, is typically every layer 1/2 inch to 1 inch.The used water yield is that mixed stucco blend can be sprayed, and can not be rare to sliding from the wall surface when spray.In a word, adding entry is about 25% to about 60% available effect for dry mixture weight.

Illustrate the various embodiment of Sprayable plastics composition of the present invention in the following Example.Embodiment 1 to 4, and the hydroxypropyl Natvosol that has hydroxyethyl MS in the table 2 that is shown in the specific example of being discussed and hydroxypropyl MS except use is as the thickening material, uses 3 compositions that are shown in table 1.

The modulation of Sprayable plastics composition of the present invention is that the first two component lift-over of table 1 is mixed into basically degree uniformly.Dry mixture is added in the water in the special mixing device, a mortar mixing machine (Putzmeistermixing Machine) for example in the building site, and wet mixture pumping is immediately come out, and be sprayed onto on the wall surface by a nozzle.Then, process was smeared this plaster and wet operation with trowel in later 1 to 2 hour continuously, thereby obtained a slick finish surface.

Sometimes the used plaster of building industry is so fresh, so that when it does not cool down as yet fully, just and thickening material carry out the dry type mixing.This is like this in summer really, because cool off summer slowly.In this case, the thickening material of prior art, methylhydroxypropylcellulose for example is owing to the amount of residual heat will of hot plaster demonstrates inferior water-soluble.The hydroxypropyl Natvosol than the thickening material of prior art superior be: the solubleness of hydroxypropyl Natvosol in water does not reduce when mixing with hot plaster.At high temperature, the thickening material of prior art, as the solubleness reduction of methylhydroxypropylcellulose, the result causes water-retentivity to reduce, and this makes that stucco blend is difficult to use, particularly when finish.

Estimate the performance of the hydroxypropyl Natvosol in the Sprayable plastics with following test method.

Dehydration is appraisal bleeding amount that it stands when the same adsorption surface of composition contacts or a tolerance of fluid loss.A low dehydration value is desirable, because of dehydration excessively can make intensity reduce and makes the plaster cracking of having done.Fluid loss is 10 graceful (Whatman) 40 of 9.0 centimetres of waters ^#Garden shape filter paper is nailed together, and with its indicated weight.Then, this filter paper is stacked in the plane, cover graceful (Whatman) 40 of water of 11.0 centimetres of one decks ^#Filter paper.Is a diameter 2 inch, the cylinder of long 3 inch be placed on filter paper layer above.With the wet mortar mixture this cylinder is full of fully.Removed this cylinder and one 4 in whole one minute later on ^#Filter paper weighs this filter paper layer with calibrating weightening finish, with the gram numerical table it, this is the fluid loss of expression from mortar composition just.

With gravimetric determination amount of air entrained in composition.Wet Sprayable plastics mixture is put into the cylinder of a known volume, and rap 100 times to remove any big air filled cavity.The mixture of sawing next known volume at the mixture on cylinder top.Measure the weight of this mixture.Write down the proportion of wet mixture and in mixture the known proportion of solid, the volume of air in the wet mixture is just calculated.In plaster, have high-load air to meet the demands because this can cause one that mix well and as the buttery denseness.

Sag resistance and spray characteristics have been measured.

Performance with the Sprayable plastics of hydroxypropyl Natvosol preparation tabulates 2 as follows.

Read above-mentioned open after; characteristic of the present invention; advantage and other certain embodiments contents can become very obvious for those general prior aries; in this respect; though specific embodiment of the present invention has been described quite in detail; and do not breaking away under disclosed by the invention and the claimed spirit and scope, these embodiment contents can change and revise.

Claims (6)

1, dry plaster composition with the plaster of Paris of about 99.95 (weight) % and water-retaining admixture from about 0.05 (weight) % to about 1.0 (weight) %, said composition, when being mixed the water think itself weight from about 25 (weight) % to about 60 (weight) %, can preparation can thin layer be sprayed on the plaster on the substrate, it is characterized in that, this water-retaining admixture is a kind ofly to have with the mole mean number of every Mierocrystalline cellulose anhydroglucose unit bonded hydroxyethyl substituted radical from about 0.3 to about 4.0 at least, with the mole mean number of every Mierocrystalline cellulose anhydroglucose unit bonded hydroxypropyl substituted radical greater than 0.35 and ash content be equal to or less than 5% hydroxypropyl Natvosol.

2, claim 1 described composition, wherein the hydroxypropyl Natvosol have with every Mierocrystalline cellulose anhydroglucose unit bonded hydroxypropyl substituted radical the mole mean number be at least 0.6.

3, claim 1 described composition, wherein the hydroxypropyl Natvosol have with every Mierocrystalline cellulose anhydroglucose unit bonded hydroxyethyl substituted radical the mole mean number from about 0.7 to about 1.8 and have with every Mierocrystalline cellulose anhydroglucose unit bonded hydroxypropyl substituted radical the mole mean number from about 0.6 to about 1.2.

4, claim 1 described composition also is included as about 0.01% to 1.0% hydroxypropyl melon ear number of its dry composition weight.

5, claim 2 described compositions also contain promising its dry composition weight from about Rhoximat RH 148 of 0.01% to 1.0%.

6, claim 3 described compositions also contain promising its dry composition weight from about Rhoximat RH 148 of 0.01% to 1.0%.