EP0541542A1

EP0541542A1 - Quick-acting joint sealing compounds

Info

Publication number: EP0541542A1
Application number: EP90914916A
Authority: EP
Inventors: Helmut Loth; Bernhard Dr. Knop; Tore Podola; Klaus Helpenstein
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1989-10-19
Filing date: 1990-10-10
Publication date: 1993-05-19
Also published as: BR9007764A; US5118730A; CN1051051A; MX172029B; EP0423611A1; JPH05500975A; CA2069934C; KR920702400A; CA2069934A1; WO1991005827A1

Abstract

Matériaux pour garnitures de joints susceptibles d'être exposées prématurément à l'eau de pluie et résistant à celle-ci, contenant: des dispersions polymères aqueuses (I); des éthers cellulosiques non ioniques (II) appartenant au groupe comprenant l'hydroxyéthylcellulose, l'hydroxyéthylméthylcellulose, l'hydroxypropylméthylcellulose et l'hydroxypropylcellulose, des charges, et, le cas échéant, des adjuvants courants, tels que pigments, plastifiants, diluants, épaississants, agents antimousse, auxiliaires dispersants, régulateurs de pH et agents de conservation et d'anti-vieillissement, préparés par mélange intime de (I) avec les autres constituants. Afin de pouvoir incorporer (II) en des quantités se situant au-dessus de la limite de solubilité, les matériaux pour garnitures de joints sont caractérisés en ce que (II) est mélangé sous forme retardée, additionné de charges et incorporé.Materials for gaskets susceptible to premature exposure to and resistant to rainwater, containing: aqueous polymer dispersions (I); nonionic cellulose ethers (II) belonging to the group comprising hydroxyethylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose and hydroxypropylcellulose, fillers, and, where appropriate, common adjuvants, such as pigments, plasticizers, diluents, thickeners , anti-foaming agents, dispersing aids, pH regulators and preservatives and anti-aging agents, prepared by intimately mixing (I) with the other components. In order to be able to incorporate (II) in amounts above the solubility limit, the materials for gasket liners are characterized in that (II) is mixed in delayed form, added with fillers and incorporated.

Description

Early joint-proof joint sealing compounds

The invention relates early to rainproof joint sealants

- aqueous polymer dispersions (I)

- Non-ionic cellulose ether (II) from the group formed by hydroxyethyl, hydroxyethyl ethyl, hydroxypropylmethyl and hydroxypropyl cellulose

- fillers as well

- If necessary, customary additives such as pigments, plasticizers, extenders, thickeners, defoamers, dispersing agents, pH regulators and preservatives and anti-aging agents and can be prepared by intimately mixing (I) with the other constituents and a process for producing such jointing compounds and their use.

REPLACEMENT LEAF: Joint sealants are known to the person skilled in the art and have proven themselves in practice. The use of joint sealant is problematic in areas where there is the possibility or the risk that the joint sealant is exposed to water pollution, for example by spray water or rain, before it hardens. For example, many of the jointing compounds that have also been used in the exterior have been wholly or partially washed out by a heavy downpour that started shortly after they were applied. DE 3814078-Al discloses the use of non-ionic cellulose ethers in joint sealants or coating compositions based on acrylate dispersions. The use of certain cellulose ethers in these compositions is said to improve the washout behavior through the action of water such as rainwater and the smoothing behavior. The amounts of the specified cellulose ether types used there are based on the solids content of the acrylate dispersion. No explicit statement is made about the ratio of "free" water to the cellulose ethers. The examples show that the components listed there for the production of a joint sealant were produced in a planetary mixer, but there is no information about the form and sequence in which the individual components are mixed with one another.

However, it has been found in practice that the addition of the individual constituents and their shape is not arbitrary in the case of such early rainproof joint sealing compounds. For example, the aforementioned cellulose ethers can be sprinkled and dissolved in small amounts in some polymer dispersions on a laboratory scale, but not on a production scale and not in amounts that are too large in relation to the "free" water to achieve a complete solution. Such an attempt inevitably leads to lump formation or breakage of the dispersion. Even if it is sometimes possible to homogenize the cellulose ether clusters again, it is not feasible to disperse dispersion particles once coagulated. Also, DE 3814078-Al does not offer the person skilled in the art any indication that such early rain-resistant joint sealants can be prepared with aqueous polymer dispersions other than the acrylate dispersions specified there.

Non-ionic cellulose ethers are also known as constituents of coating compositions and paints, e.g. those based on aqueous dispersions of organopolysiloxanes as described in DE 1284007 or those based on vinyl acetate / maleic acid dibutyl ester dispersions as described in DE 21 08365. However, the person skilled in the art cannot derive any indication that such cellulose ethers are also suitable for joint sealants based on the same polymer dispersion and lead to the desired effects.

The specialist magazine Resin Review 35.2 describes a roof coating composition which contains a polyacrylate dispersion as a binder and, in addition to fillers and other auxiliaries, also contains hydroxyethyl cellulose as a thickener. This coating composition is advertised as being particularly resistant to washing out. However, this property is attributed to the specific setting behavior of the polyacrylate emulsions specially developed and used for such coating compositions. It was therefore not obvious to a person skilled in the art to use hydroxyethyl cellulose in joint sealants to improve the early rain strength.

In addition, coating compounds do not meet the requirements placed on joint sealing compounds. These are in particular requirements such as those required by DIN 52456 "Determining the Processability of Sealants" and DIN 52454 "Stability". In particular when it comes to durability, joint sealing compounds must have the property that they do not run off, or only slightly, from a U-profile filled with this compound, which is placed upright after filling. Coating compositions are generally of low viscosity, since on the one hand they should be able to be applied by spraying or rolling and on the other they should show a certain course for leveling the composition. Although joint sealants and coating compounds can in principle be produced from the same constituents, it should also be possible to produce a reasonably usable coating compound by diluting a joint sealant, but conclusions cannot necessarily be drawn in the reverse manner.

From Ullmann, Encyclopedia of Industrial Chemistry, 4th edition, Volume 9, Verlag Chemie, Weinheim / Bergstrasse 1974, pages 208-209, it is known that nonionic cellulose ether derivatives such as hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (HEMC) and hydroxy - Propyl-methylcellulose (HPMC) can be used in plastic plasters and emulsion paints, among other things, to improve water retention, open time, wet grip and thickening and setting behavior. However, the person skilled in the art cannot derive any indication that such cellulose ethers in joint sealing compounds lead to an improvement in the spreadability, the smoothing behavior and the splash water resistance of the as yet unhardened surfaces of these compounds. Furthermore, paints such as emulsion paints and plastic mortars represent another area of technology that is not comparable to joint sealants. So plastic plasters can possibly be used to fill joints, but generally have no pronounced sealing properties and, in contrast to the Portion and process joint sealants when applied with a trowel.

The object of the invention is to provide joint sealants based on polymer dispersions which, in addition to good smoothing behavior, have an early rain resistance of the uncured compositions without other desired properties such as modulus of elasticity, elongation at break and resilience, and resistance to migration and coagulum and Speck freedom can be adversely affected. It was also an object of the invention to provide a method which makes it possible to produce such compositions.

The object was achieved by early rain-resistant joint sealants containing aqueous polymer dispersions (I), non-ionic cellulose ethers (II) from that of hydroxyethyl,

Hydroxyethyl ethyl, hydroxypropylmethyl and hydroxypropyl cellulose formed group

Fillers and, if appropriate, customary additives such as pigments, plasticizers, extenders, thickeners, defoamers, dispersants, pH regulators and preservatives and anti-aging agents and can be prepared by intimately mixing (I) with the others

Ingredients, characterized in that (II) in retarded

Form mixed with the fillers added and mixed.

The individual components of the joint sealing compound are known to the person skilled in the art as such, for example from DE 3814078-A1. Further suitable polymer dispersions for the production of joint sealants are commercially available and / or are known to the person skilled in the art from the patent and specialist literature, for example from E. Flick, Construction and Structural tural adhesives and sealants, Noyes Publications, Park Ridge 1988 or E. Flick, Adhesives and sealant compound formulations, Noyes Publications, Park Ridge 1978. Particularly advantageous joint sealants contain dispersions of polyacrylates and / or acrylate copolymers capable of film formation. Also advantageous are joint sealants according to the invention which are selected from dispersions of polymers or copolymers capable of film formation from those of ethylene / vinyl acetate, butadiene / styrene, vinyl acetate / maleic acid ester, silicone, urethane, vinyl acetate methacrylic acid / chloroprene and isoprene -Polymers or copolymers based group. Different polymer dispersions can be combined. Polysulfide dispersions have also proven to be particularly suitable in connection with polymers capable of film formation. For the sake of simplicity, the following text speaks only of polymer dispersions.

Most of the ingredients are commercially available. Both retarded and non-retarded cellulose ethers are commercially available. Retarded cellulose ethers are understood to mean those that swell in water after a delay compared to the unretarded substances. This will e.g. achieved by crosslinking with glyoxal on the surface of the cellulose ether particles, as described, for example, in DE 24 15556. While it was previously customary to introduce the cellulose ethers mentioned already in aqueous solution or in amounts which can be readily dissolved in the "free" water already contained in the composition, the joint sealing compounds according to the invention are characterized by a new production process with regard to the introduction the cellulose ether.

The retarded cellulose ethers can be mixed with the fillers. For this purpose, these two components are intimately mixed in advance. It is also possible to if other solid constituents, for example pigments, are also mixed in.

In a preferred production process of the joint sealing compounds according to the invention, cellulose ether is added to the polymer dispersion in finely divided form, mixed with the filler and intimately mixed. Polymer dispersions with a very high solids content can optionally be slightly diluted beforehand. The pH regulators are added last, the further additives optionally being able to be mixed in before and / or after the addition of the filler.

The aqueous dispersions contained in the joint sealants of the invention preferably have solids contents of 40 to 75, in particular 45 to 65% by weight. Their pH value can be at least 6, in particular 7 to 9, and is adjusted to these values if necessary.

The cellulose ethers contained in the joint sealing compounds according to the invention preferably have a Brookfield viscosity of at least 5,000 Pas as a 2% aqueous solution at 20 ° C. Those with a value of at least 25,000 mPas, for example middle viscous hydroxyethyl celluloses, are preferred. So-called highly viscous cellulose ether types which have a corresponding value of at least 70,000 mPas are particularly suitable, e.g. highly viscous hydroxyethyl cellulose. Commercial high viscosity hydroxyethyl cellulose e.g. as a 2% solution at 20 ° C a viscosity of 100,000 mPas.

According to the manufacturer's instructions, complete solutions can no longer be achieved with hydroxyethyl cellulose, for example with Natrosol 250 HHR at a viscosity above 200,000 mPas. With the less This limit is even lower for hydrophilic cellulose ethers which can be used according to the invention, for example about 150,000 mPas for hydroxypropyl cellulose or about 100,000 mPas for hydroxypropyl methyl cellulose. With a higher concentration, gel-like masses increasingly form. However, this seems to play a special role in the early rain resistance of the joint sealing compounds according to the invention. Even if the exact relationships have not been clarified, it can nevertheless be assumed that if this solubility limit is exceeded, an increasing build-up of a gel-like structure contributes to the fact that, even in the uncured state, the masses are not or only slightly washed out by water pollution such as rain.

In this context, the ratio of the amounts of cellulose ether to "free" water is obviously important, which is decisive for whether this solubility limit is exceeded or not. "Free" water is understood here to mean the water content of the sealing compound which is available to the cellulose ethers in order to dissolve in it. This means that the total water content of the joint sealant cannot be used for a corresponding calculation. Rather, it must be taken into account that the other constituents likewise require a certain amount of water or bind more or less firmly. So-called water values are known for most fillers. In the case of heavy spar, for example, this is 11 g of water per 100 g of heavy spar. For silica, for example for the HDK V 15 type from Wacker-Chemie, values between 350 and 400 g water per 100 g silica can be determined. Such values provide the person skilled in the art with an indication of the amounts of “bound” water that he has to subtract from the total water content of the sealant in order to obtain the amount of “free” water. It is therefore preferred that this amount of "free" water in relation to the amount of the cellulose ether type used in each case results in a ratio which is above the respective solubility limit. The situation becomes somewhat more complicated if the person skilled in the art has to take into account a water requirement which arises when the dispersed polymers contain groups capable of salt formation. If there is such an additional water requirement, the person skilled in the art may have to consult the appropriate manufacturer's information, estimate this need on the basis of empirical values or approximately determine it by simple manual tests. If a joint sealing compound is to be produced in which the solubility limit mentioned is exceeded, the cellulose ethers cannot be added in the usual way - ie as a solution. The method according to the invention shows a way of producing such joint sealing compounds.

Furthermore, fillers can be contained in the joint sealants of the invention in an amount of 2 to 60, in particular 35 to 60% by weight, based on the total mass of the joint sealants. Such compositions, if they contain only a little filler, can have a certain transparency. Low filler contents can be present, in particular, in those compositions in which the fillers have an additional thickening effect, such as silica. If only fillers that do not have this additional effect are used, their content is usually between 35 and 60% by weight. One speaks here of highly filled masses.

According to a further advantageous embodiment of the invention, the jointing compounds contain chlorinated hydrocarbons, in particular chlorinated paraffins, as plasticizers, and nonionic surfactants as wetting agents. Commercial chlorinated paraffins with a chain length of about 10 to 18 carbon atoms and a chlorine content of about 40 to 70% by weight are preferred.

In a preferred embodiment, the joint sealants contain 25 - 90 wt .-% polymer dispersion, with highly filled

Joint sealants, in particular 25-40% by weight polymer dispersion,

2-60% by weight, in particular 35 to 60% by weight, of fillers 0-1% by weight, in particular 0.3 to 0.5% by weight of wetting agent 0-20% by weight, in particular 5 to 15 plasticizers and 0 10% by weight, in particular 4 to 6% by weight, of other customary ones

Additives such as thickeners, defoamers and pigments and up to

1.5% by weight cellulose ether

-% by weight based on the total amount -

The cellulose ether content should not be much less than 0.1% by weight. Good results are shown in particular in the case of joint sealing compounds in which, taking into account the general parameters such as cellulose ether type and free water content, the cellulose ether content is in a range from about 0.1 to 0.5% by weight, based on the total amount .

Furthermore, it is preferred to add the pH regulators, in particular the bases, in the preparation only after the addition of the cellulose ethers. This is of particular advantage in the case of retarded cellulose ethers, since the retardation is eliminated more quickly in the basic region. On the other hand, a neutral to basic setting of the joint sealants can have a favorable effect on their stability, in particular on their shear stability.

To avoid stirring in air and the formation of air bubbles in the product, stirring can be carried out under vacuum. The joint sealants are preferably used as intended. They are particularly suitable for use in areas in which they are exposed to splash water, rain or other early water pollution.

The invention is explained in more detail below on the basis of preferred exemplary embodiments.

B e i s p i e l e

The masses described in the examples and further masses produced for comparison purposes were subjected to a washout test, a sprinkling apparatus according to DE 3814078-A-1 FIG. 1 being used; the same apparatus is shown in side view in FIG. 2.

The irrigation equipment consisted of a housing made of transparent plastic with the dimensions: height 70 cm, width 60 cm and depth 60 cm. It comprised a housing 1, a shower head 2, a sample bowl 3, a pump 4, a floor drain 5 and a shut-off valve 6 for the drain. The sample pan consisted of a vessel measuring 7 x 7 cm and had a depth of 2.5 cm. The shower head was a conventional hand shower as used for body care and was set so that the sample was irrigated evenly. The distance between sample 3 and shower head 2 was 30 cm.

The apparatus was operated with demineralized water, the pump generating an excess pressure of approximately 0.4 bar. The water flow rate was 300 l / h. The spraying with water was carried out 5 minutes, in each case 1 minute after filling and smoothing the surface of the masses to be tested. The washout (in% by weight) was determined by differential weighing before and after sprinkling.

The processability was measured according to DIN 52456. A 4 mm bore, a pressure of 2 bar and a test volume of 200 ml were used.

The compositions described in the examples were also subjected to a test for their smoothness behavior. This test was carried out by 7 independently working people so that after applying a 30 cm long strand of mass to a smooth, flat, dark surface, the mass was smoothed with a spatula and fingers. The smoothness behavior was assessed on a scale from 1 (= very good) to 6 (= insufficient).

example 1

The following components were mixed intensively in a planetary mixer for a total of about 30 minutes:

1200 g commercially available dispersion of an acrylic acid ester copolymer with approximately 55% by weight solid and free carboxy groups Trade name: Prima1 E 1785

200 g polybutene as an extender

20 g Ethyleneπoxidaddukt as wetting agent

4 g commercially available halogenated preservative (AKTIZID TL 526)

200 g of butyl benzyl phthalate as a plasticizer

200 g water

80 g aliphatic low aromatic solvent (SHELLS0L D 60)

4 g highly viscous hydroxyethyl cellulose (NATROSOL 250 HHR)

2040g uncoated chalk

40 g titanium dioxide and

12 g of 25% aqueous ammonia solution

Processability according to DIN 52456: 1000 g / min Smoothing behavior: good

Washout: 4.3% loss

The procedure was as follows, that the dispersion was introduced, then the polybutene, the ethylene oxide adduct, the preservative, the plasticizer and the water and the solvent for about 5 minutes were intimately mixed together. The chalk and titanium dioxide were then mixed with the hydroxyethyl cellulose and incorporated into the batch. The mixture was stirred for 10 minutes. After the ammonia had been added, stirring was continued for a further 15 minutes under vacuum at 40 mbar.

Example 2

The following components were mixed intensively in a planetary mixer for a total of about 45 minutes:

1750 g of aqueous, commercially available polybutyl acrylate dispersion

(approximately 62% solids), a pH of 6.0-6.5, a glass transition temperature Tg -50 ° C, a viscosity of approximately 250 mPas at 23 ° C and an average particle size of 0.4 μm, 250 g Chlorinated paraffin (C12-C14, 49% chlorine), 2800 g barium sulfate (commercial product: Schwerspat EW0), 100 g titanium dioxide (commercial product KR0N0S RN 56), 25 g sodium carbonate (technically pure commercial product), 25 g ethylene oxide adduct (approximately 9.5 E0 ) of nonylphenol, 5 g of commercially available halogenated preservative, 37 g of hydroxyethyl cellulose with a viscosity of about 4000 mPas of a 1% strength aqueous solution at 20 ° C. and a hydroxyethyl group content of 55% by weight, trade name: Natrosol 250 HHR.

The procedure was such that the polymer dispersion was initially introduced. The ethylene oxide adduct (emulsifier), the preservative and the chlorinated paraffin were then added. Subsequently, the hydroxyethyl cellulose was intimately mixed together with the barium sulfate (filler) and the titanium dioxide and mixed into the batch in this form. After adding the sodium carbonate as 10% aqueous solution was again mixed thoroughly under vacuum.

Processability according to DIN 52456: 2260 g / min Smoothing behavior: good

Washout: 1% loss

The following results were found when a total of 50 g of the same hydroxyethyl cellulose was added:

Processability according to DIN 52456: 1300 g / min Smoothing behavior: very good

Washout: 0.3% loss

Example 3

The following components were mixed intensively in a planetary mixer for a total of about 40 minutes:

1400 g of aqueous, commercially available polybutyl acrylate dispersion

(approximately 62% solids), a pH of 6.0 - 6.5, a glass transition temperature Tg -50 ° C, a viscosity of about 250 mPas at 23 ° C and an average particle size of 0.4 μm, 200 g of polybutene, 12 g of ethylene oxide adduct (approximately 9.5 E0) with nonylphenol, 8 g of commercially available halogenated preservative, 10 g of sodium carbonate (technically pure commercial product), 146 g of tap water and 20 g of hydroxyethyl cellulose with a viscosity of approximately 4000 mPas of a 1% strength aqueous solution Solution at 20 ° C and a hydroxyethyl group content of 55% by weight, trade name: Natrosol 250 HHR 80 g titanium dioxide 1008 g barium sulfate (Schwerspat EW0) 1096 g calcium carbonate (Omega BLP 3) 20 g hydrocarbons (with a KP of 180 ° C - 210 ° C like crystal oil 60 )

Processability according to DIN 52456: 2830 g / min Smoothing behavior: good

Leaching: 1.7% loss

The procedure was such that the polymer dispersion was initially introduced. The ethylene oxide adduct (emulsifier), the preservative, the polybutene and the crystal oil were then intimately mixed with one another. The chalk, titanium dioxide and barium sulfate were then mixed with the hydroxyethyl cellulose and incorporated into the batch. The mixture was stirred for about 10 minutes. After the sodium carbonate had been added, dissolved in water, stirring was continued for a further 15 minutes under vacuum.

Claims

Patent claims

1. Containing early rainproof joint sealants

- aqueous polymer dispersions (I)

- Non-ionic cellulose ether (II) from the group formed by hydroxyethyl, hydroxyethylmethyl, hydroxypropyl ethyl and hydroxypropyl cellulose

- fillers as well

- If necessary, customary additives such as pigments, plasticizers, extenders, thickeners, defoamers, dispersants, pH regulators and preservatives and anti-aging agents and can be prepared by intimately mixing (I) with the other constituents, characterized in that (II) in a slow-release form, mixed with the fillers and added.

2. Joint sealing compounds according to claim 1, characterized in that they contain dispersions of polyacrylicates capable of film formation and / or acrylate copolymers.

3. Joint sealants according to claim 1, characterized in that they selected dispersions of film-forming polymers or copolymers selected from the group consisting of ethylene / vinyl acetate, butadiene / styrene, vinyl acetate / maleic acid ester, silicone, urethane, vinyl acetate methacrylic acid / Contains chloroprene and isoprene polymers or copolymers.

4. Joint sealing compounds according to one of the preceding claims, characterized in that they contain an aqueous dispersion of poly-sulfide poly.

5. Joint sealing compounds according to one of the preceding claims, characterized in that the aqueous polymer or copolymer dispersions have solids contents of 40 to 75% by weight, in particular 45 to 65% by weight.

6. Joint sealing compounds according to one of the preceding claims, characterized in that cellulose ethers are contained which, in 2% strength aqueous solution at 20 ° C., have Brookfield viscosities of at least 5000, in particular at least 25,000, preferably at least 70,000 mPas.

7. Joint sealing compounds according to one of the preceding claims, characterized in that the ratio of cellulose ethers to free water is selected such that a complete solution of the cellulose ethers can no longer be achieved.

8. Joint sealing compounds according to one of the preceding claims, characterized in that they

25 - 90 wt .-% polymer dispersion, with highly filled

Joint sealants, in particular 25-40% by weight polymer dispersion,

2-60% by weight in particular 35 to 60% by weight of fillers 0-1% by weight in particular 0.3 to 0.5% by weight of wetting agent 0-20% by weight in particular 5 to 15 plasticizers and 0 10% by weight, in particular 4 to 6% by weight, of other customary ones

Additives such as thickeners, defoamers and pigments and up to

1.5% by weight of cellulose ether -% by weight in each case based on the total amount -

contain.

9. A process for the preparation of jointing compounds, characterized in that the cellulose ethers finely divided in the filler are added to the polymer dispersion and intimately mixed, then the pH regulators - in particular bases - are added and the submixture of the other usual ones Additions optionally take place before and / or after the addition of the filler.

10. Use of the joint sealants as such, in particular in areas where the joint sealants can be exposed to splashing water or rain.