JPH0350768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a room-temperature storage-stable liquid solution comprising a polyisocyanate and a polyol, the polyisocyanate being dispersed in the polyol in the form of discrete particles whose surfaces are inert. or a pasty thermosetting substance mixture, its production method and use.

The preparation and direct use of combinations of polyisocyanates and binders containing isocyanate-reactive atomic groups are known.

However, a major drawback of this is that the isocyanate groups cannot react already at room temperature with the corresponding reaction components, such as polyols or polyamides, ie form storage-stable combinations.

To circumvent this difficulty, two-component systems are often used. In this case, the reaction components are stored in separate formulations and are mixed only immediately before application;
The reaction then proceeds spontaneously or promoted by heat and/or a catalyst.

Examples of such materials include U.S. Pat.
Examples include those described in specification No. 4029626. Disadvantages of the process disclosed therein include the difficulty of having to prepare and store both components separately and the risk of clogging of the mixing and application equipment due to premature reactions. be.

Another method for producing storage-stable polyisocyanate materials starts from so-called prepolymers which contain only small amounts of free isocyanate and are not crosslinked, using air humidity as the crosslinking agent. Ru. This method is described, for example, in FR 1237936. The disadvantage in this case is that the curing proceeds very slowly from the surface into the depths of the coating, the final properties are only achieved after several weeks or months, and no curing occurs, for example in the middle or in the hollows of large areas. It is in.

Stable systems can also be formed by first reacting the polyisocyanate with a monofunctional reactant. The resulting adducts are referred to as capped or blocked isocyanates if they are less thermally stable than the products of the subsequent crosslinking reactions. The capping agent separates under the action of heat and the polyisocyanate begins to form more heat-stable bonds under crosslinking.

This principle can be seen, for example, in Vieweg and Hochtlen, “Kunststoff-
Handbuch” Volume 1, Polyurethane (Karl Hanser Verlag, Millungen, 1966), pages 11 onwards, and a series of patent specifications, such as German Patent Application No. 2640295,
This is the basic idea of Specifications No. 2612638 and No. 2639491, and Specification European Patent No. 0000060.

The technical and economical disadvantages of such formulations arise from the capping agent separating, which changes its properties if it remains in the crosslinked material, or which is removed from the recovery or exhaust air if vaporized. Must be.

Federal Republic of Germany Patent Application Publication No. 1570548, German Patent Application Publication No. 2842805 and the same
No. 2921162 specifies that temperatures of 100℃ or higher or 130℃
A polyisocyanate that melts as described above is disclosed,
The polyisocyanates together with special polyols form storage-stable combinations that can be cured under the action of heat into coatings for woven fabrics or braided tubes.

The technical disadvantage of the combinations derived from the above publications is that they require a very narrow selection of specifically configured polyols in order to achieve good storage stability, and therefore for a series of applications, e.g. It's completely inappropriate.

German Patent Application No. P3112054.7 discloses that, in a substance mixture consisting of polyisocyanate and polyol, the surface of the polyisocyanate particles is
Inactivation was disclosed such that 20 equivalent % was inactivated.

The object of the invention is to create a storage-stable, thermosetting liquid or paste consisting of polyisocyanate and polyol, which does not have the above-mentioned disadvantages and in which the surface of the polyisocyanate particles is optionally still slightly inactivated. The objective was to provide a mixture of substances.

The subject of the invention is a polyisocyanate and a polyol, optionally containing additives such as protective colloids, inert solvents, softeners, pigments, fillers, pigments or other auxiliaries customary in coating technology. A storage-stable liquid or pasty thermosetting substance mixture in which the polyisocyanate is dispersed in the form of discrete particles with a particle diameter of 0.1 to 150 μm in a polyol optionally containing the abovementioned additives. and the surface of the polyisocyanate particles is inactivated, with 0.01 to 0.499 equivalent % of the total isocyanate groups present being inactivated by a primary or secondary amine or water, or It is characterized in that 0.01 to 20 equivalent % of all the isocyanate groups present are inactivated by adding a compound containing a carboxyl group, a phenolic hydroxyl group, an amide group or a hydrazide group.

Furthermore, the subject of the invention is a process for the preparation of said substance mixture, which process comprises dispersing the polyisocyanate in a polyol and a deactivating agent already contained in the polyol or dispersing the polyisocyanate in the polyol. Advantageously, the polyisocyanate may be added at least in part to the solution later or the polyisocyanate may be added first.
by treatment with a deactivating agent at a temperature below 40° C. and subsequent dispersion in a polyol, in which case the deactivation reaction can optionally be accelerated by the presence of a suitable selectively acting catalyst. can.

In order to promote and control the deactivation, suitable and advantageous catalysts which selectively promote the deactivation can also be used in combination.

Furthermore, the subject of the invention is the use of the substance mixtures according to the invention as coatings, adhesives or sealants for metals or nonmetals and in particular as undersealing materials and sound-dampening materials in motor vehicles and for multi-glazed windows for thermal insulation and sound-damping purposes. It is used as a sealing material.

The invention eliminates the disadvantages of the prior art in that the polyisocyanate is dispersed in the polyol in the form of separate particles and the surface of the dispersed particles is inertized by a chemical reaction. Only a relatively small portion of isocyanate is consumed for inactivation, so that the particles still remain reactive.

During thermal curing, phase separation is prevented by dissolution or melting processes and crosslinking can take place.

Next, the constituent components of the substance mixture of the present invention will be explained.

Suitable polyisocyanates are the customary aliphatic, cycloaliphatic and aromatic di- and polyisocyanates, which can be prepared, for example, by addition of diisocyanates to di-, tri- or polyols or from diisocyanates by duplexation to form uretdiones. ,
It is obtained by trimerization to give the isocyanurate and biuretation with amine or water.
The following diisocyanates are particularly suitable for this purpose, such as diphenylmethane diisocyanate, toluylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.

Preferably, the polyisocyanates are polyisocyanates that are solid at room temperature, such as addition products of toluylene diisocyanate and trimethylolpropane or cyanurates consisting of 3 mol of toluylene diisocyanate, and in particular sparingly soluble powdered dualized toluylene diisocyanates containing uretdione groups. It is an isocyanate.

Suitable polyols include polyesterols, polyetherols and hydroxyl group-containing polymers commonly used in polyurethane chemistry, such as olefinically unsaturated monomers without active hydrogen;
It is a copolymer with an olefinic unsaturated monomer having active hydrogen.

Suitable monomers without active hydrogen are, for example, vinyl aromatic compounds such as styrene or vinyltoluene, olefins such as ethylene or propylene, acrylic or methacrylic acid esters such as butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, linear or vinyl esters of branched carboxylic acids such as vinyl acetate, vinyl propionate or vinyl pivalate and vinyl ethers such as vinyl isobutyl ether.

Suitable monomers having hydrogens reactive toward isocyanate groups are, for example, mono(meth)acrylic esters of polyhydric, especially dihydric alcohols, such as butanediol monoacrylate, hydroxypropyl (meth)acrylate, and other covalent monomers. Polymerizable olefinically unsaturated hydroxyl-containing compounds, such as vinyl glycols, and amine- and/or
or copolymerizable olefinically unsaturated compounds having amide groups, such as acrylamide and methacrylamide.

The substance mixtures according to the invention contain the polyisocyanate dispersed in the polyol in the form of discrete particles with a particle diameter of 0.1 to 150 μm, preferably 1 to 50 μm, the isocyanate groups and the hydroxyl groups generally being 0.5 μm. :1~1:0.5, advantageously 0.9:1
Present in a quantitative ratio of ~1:0.9.

However, the invention is not limited to the amounts stated above; for specific purposes, for example as adhesives for removable metal labels, for example mixtures with significantly insufficient amounts of isocyanate are suitable.

The surface of the dispersed polyisocyanate particles is inactivated to such an extent that no reaction between the polyisocyanate particles and the polyol occurs at room temperature.

The deactivating agent is advantageously selected in such a way that the surfaces of the polyisocyanate particles are bonded by chemical or physical forces, so that a phase separation occurs between the polyisocyanate and the polyol.

For chemical inactivation, from 0.01 to 0.499 equivalent % of the total isocyanate groups present, advantageously from 0.1 to
0.4 equivalent % with primary or secondary amines or water as deactivating agent or 0.01 to 20 equivalent % of the total isocyanate groups present, advantageously 1 to 10 equivalent % with carboxyl groups, phenolic hydroxyls. with a compound containing a group, an amide group or a hydrazi group.

For this purpose, deactivators can be added to the batch in the equivalent ratios stated in the claims. A method in which the deactivating agent is added in excess of the equivalent ratio stated in the claims is also suitable.

After the surface of the dispersed phase is coated with the deactivating agent, the deactivating reaction is stopped.

Suitable deactivators are water, mono- and polyamines, mono- and polyalcohols. Particularly suitable are long-chain monoamines, such as stearylamine, which forms a kind of grafted emulsifier. A polymeric polyamine, such as a polyamidoamine, and a hydroxyl-terminated polymer, such as a hydroxyl-terminated polybutadiene oil, react to form a grafted protective colloid. Particularly suitable for inactivating the isocyanate groups on the surface of the polyisocyanate particles, ie for stabilizing the isocyanate/polyol dispersion, are also reactions that form urea or polyurea structures on the isocyanate. This is because they are insoluble in most polyols and organic solvents. Substances forming such ureas or polyureas are water and primary or secondary amines, in which case short-chain diamines such as ethylene diamine or propylene diamine are preferred. Polyureas formed from these short-chain diamines are more organophobic than those formed from long-chain diamines and therefore have a better stabilizing effect. A preferred method of operation starts from a sparingly soluble powdered dimerized toluylene diisocyanate. Since isocyanates react much more rapidly with primary amines than with polyols, storage-stable mixtures can be obtained directly, for example, by incorporating powdered dualized toluylene diisocyanate into diamine-containing polyetherols.

The advantage of this method is that the urea structure is further reacted with another isocyanate at high temperature to form a biuret structure, i.e. the passivating agent is incorporated into the crosslinked system and does not leave behind any heterogeneity. .

As deactivating agents, compounds containing carboxyl groups, such as homo- and copolymers of acrylic acid, methacrylic acid, maleic acid and other polymerizable acids, acidic polycondensation products, such as those prepared in excess of acid, can also be used. polyesters, such as acidic polymers obtained by alcoholysis of adducts of maleic anhydride to unsaturated polymers such as linseed oil or polybutadiene oil, compounds containing phenolic hydroxyl groups such as phenol, cresol, cardanol, p-tert-butyl; Phenol-2,2-bis[4-hydroxy-phenyl]-
Non-crosslinked condensation products of propane and their phenols with aldehydes such as formaldehyde (also referred to as resols), compounds containing amide groups such as soluble polyamides and polymers of acrylamide and methacrylamide or acrylamide and/or Alternatively, a copolymer of methacrylamide and acrylic acid and/or methacrylic acid ester, obtained by hydrazine decomposition of polyacrylate, and whose preparation method is described, for example, by M. Hartmann, R.
Written by Dobenko, UT Hocksbender,
“Organic Coatings＋Applied Polymer
The polyhydrazide described in "Science", Vol. 46, 1982, pp. 429-432 is applicable.

The deactivating agent generally has a molecular weight of 200 to 1,000,000, especially
It has a molecular weight of 500-5000.

Inactivating the isocyanate groups on the surface of the polyisocyanate particles, that is, isocyanate/
Particularly suitable for stabilizing polyol dispersions are polyacrylic acid, polymethacrylic acid and copolymers of these acids with each other or their esters or mixtures of their esters and polyacrylate hydrazides.

The advantage of these deactivators is that they lead to good adhesion of the cured products, for example on steel plates and electrocoated steel plates.

Optionally, it is also possible to use mixtures of the deactivating agents mentioned above with water and primary or secondary amines and polyamines.

In special implementation regulations, the substance mixture can also additionally contain customary softeners, such as esters of phthalic acid, adipic acid, sebacic acid or phosphoric acid, chlorinated hydrocarbons, epoxidized natural oils or low-molecular-weight polyesters. .

For more information on softeners, please refer to D. Wein
-mann), “Beschichtung mit Lacken und
Kunststoff” WA Colomb Publishers, Sittsgart, 1967, pages 103 et seq.

In order to adjust special processing conditions and to achieve special effects, the substance mixtures of the invention generally contain protective colloids, inert and optionally reactive solvents such as benzene, in an amount of, for example, 0.1 to 15% in the polyol. Contains esters, ketones, ethers, glycols and pigments such as carbon black, titanium dioxide, organic and inorganic colored pigments, fillers such as talc, alumina, white powder and quartz powder, pigments or other auxiliaries customary in coating technology. I can do it.

The preparation of the substance mixtures according to the invention is generally carried out using customary dispersers and mixers. The polyisocyanate is advantageously dispersed in the polyol at a temperature below 40°C, in particular between 0 and 25°C, in which case the polyol already contains the entire amount of deactivator or the deactivator is dispersed in the mixture. Add immediately after the process.

Catalysts can also be added to control and accelerate deactivation. Catalysts that selectively promote deactivation are advantageous. Furthermore, the deactivated catalyst may be the same catalyst that later promotes or controls certain thermal activation reactions.

Another method for producing the substance mixture according to the invention consists in first treating the polyisocyanate with a passivating agent, preferably at a temperature below 40° C., and then dispersing it in the polyol.

The substance mixtures according to the invention are well stable in storage at 25° C. for at least 2 months, and no loss of activity or irreversible changes in the material affecting the intended use are observed.

Curing of the substance mixture according to the invention is generally from 70 to 180°C.
Let's do it.

The substance mixtures according to the invention can be used in liquid or pasty form and are suitable as coatings, adhesives and sealants. Suitable substrates in this case are metals such as steel, aluminum, copper, magnesium (which may also be coated with a primer) and nonmetals such as glass, ceramics, heat-stable plastics and fiber substrates.

The substance mixtures according to the invention can be used with particular advantage as underseals or undercoats for motor vehicles.

Other uses and advantages are found in the good adhesion of glass, which allows its use as a seal and bonding agent for making multi-paned windows.

Next, the present invention will be explained with examples. "Parts" and "%" described in the following examples and comparative examples are "parts by weight" and "% by weight" unless otherwise specified.
It is.

Comparative Example 1 90 parts of a polyether diol based on propylene oxide with a molecular weight of approx. 450, a molecular weight of approx.
140 parts of polyether with glycerin and propylene oxide with 420 TiO ₂ (rutile form)
45 parts of white powder, 47.5 parts of iron oxide black, and 2.5 parts of iron oxide black were dispersed at about 30-35°C in a chilled dissolver, then cooled to 20°C and duplexed via uretdione formation. 4-Toluylene diisocyanate was dispersed at about 20-25°C. To this mixture was added 1 part of a 33% solution of diazabiscyclooctane in butyl glycol and 114 parts of xylene with stirring. A lacquer was thus obtained which could be applied with a conventional spray gun, which was sprayed onto a sheet and after heat treatment at 140° C. for 20 minutes formed a gray coating.

After storage for 3 days at room temperature (approximately 20-25 DEG C.), the lacquer could no longer be stirred and had solidified into a brittle material.

Example 1 The procedure was as in Comparative Example 1, but before adding the pigment a polyamide amine resin with an amine number of about 200 and a viscosity of 52 Pas at 25° C. 2.8 was added to the polyol mixture.
part was mixed with stirring.

The resulting lacquer was operated in the same manner as described in Comparative Example 1.

After two months' storage, any pigment precipitates that may have formed can be removed by simple stirring. The coatings obtained from the stored and stirred lacquer exhibited the same quality as the fresh lacquer.

Example 2 The procedure was the same as in Example 1, except that the polyamide amine resin was stirred in for the first time 10 minutes after the finely divided uretdione of 2,4-toluylene diisocyanate was dispersed.

A lacquer with the same storage stability as Example 1 was obtained.

Comparative Example 2 140 parts of a polyether triol based on glycerin and propylene oxide with a molecular weight of about 420, 300 parts of a polyether diol based on propylene oxide with a molecular weight of about 1000,
50 parts of Byakua powder, 10 parts of TiO ₂ (anatas form), and 5 parts of iron oxide yellow were dispersed at 00 to 35°C in a cooled dissolver. After cooling to 20° C., 136 parts of finely powdered 2,4-toluylene diisocyanate, which had been dualized via uretdione formation, were dispersed and 3 parts of a 33% strength solution of diazabiscyclooctane in butyl glycol were stirred in. . The material obtained could be applied to the underside of a car body at approximately 200 bar in a one-component high-pressure spackle device. 20 at 140℃
After heat treatment for minutes, a microcellular film is formed,
The coating provided effective protection against corrosion and stone impact. The material should be processed at least about 6 hours before production, since the viscosity increases rapidly thereafter. After 2 days, the material had solidified in the storage container and could no longer be stirred.

Example 3 The procedure was as in Comparative Example 2, except that after the particulate duplex 2,4-toluylene diisocyanate had been dispersed, 2.2 parts of the polyamide amine resin described in Example 1 was dispersed. The material obtained could be used as an automotive underseal material and its storage stability was at least 6 months at room temperature.

Comparative Example 3 160 parts of a polyether diol based on propylene oxide with an equivalent weight of about 1000, an OH number of about 56 and a viscosity of about 320 mPas, an equivalent weight of about 140 and an OH number of about 400
and 70 parts of a polyether triol based on glycerin and propylene oxide having a viscosity of about 365 mPas and 63 parts of 2,4-tolylene diisocyanate dualized by uretdione bonds.
part was dispersed into a well-flowing paste in a high-speed rotary dissolver. Maximizes temperature rise through cooling during dispersion process
The temperature was limited to 25℃.

Example 4 A paste was produced in the same manner as described in Comparative Example 3. However, before dispersing the dual toluylene diisocyanate, 2.5 parts of the polymer dispersion were dissolved in the polyetherol mixture. The polymer components of this dispersion were 50 parts of butyl acrylate,
It consisted of 25 parts of acrylic acid and 25 parts of methacrylic acid. The polymer dispersion was prepared based on the conventional method of emulsion polymerization. Details regarding emulsion polymerization can be found, for example, in B. Vollment, “Grundriβder
Springer Verlag, Heidelberg, 1962, pages 98 et seq.

After dispersing the double 2,4-toluylene diisocyanate, 25% of phenylmercury propionate was added.
1.5 parts of % butyl glycol solution were stirred in.

Testing of the substance mixtures obtained in Comparative Example 3 and Inventive Example 4: The paste described in Comparative Example 3 was added to a 0.5% solution of 25% phenylmercury propionate in butyl glycol.
The inventive paste of Example 4 was treated similarly, applied to a thickness of about 1 mm on a contacted and phosphatized steel plate. After heating both samples to 140° C. for 20 minutes and recooling, clear, slightly foamed, elastic coatings were obtained.

Coatings produced according to the invention from pastes partially inactivated and stabilized with polymers having terminal carboxyl groups (Example 4) adhered well to the substrate.

The coating obtained from the paste produced according to Comparative Example 3 could be smoothly peeled off from the sheet by careful pulling.

Claims (1)

[Scope of Claims] 1. Room temperature, consisting of polyisocyanates and polyols, optionally containing additives such as protective colloids, inert solvents, softeners, pigments, fillers, dyes or other auxiliaries customary in coatings technology. In storage-stable liquid or pasty thermoset mixtures, the polyisocyanate has a particle diameter of 0.1 to 150μ
m, optionally dispersed in a polyol containing the abovementioned additives, and the surface of the polyisocyanate particles is inertized, with the total amount of isocyanate groups present being deactivated.
0.01 to 0.499 equivalent % are inactivated by primary or secondary amines or water, or 0.01 to 20 equivalent % of the total isocyanate groups present are carboxyl groups, phenolic hydroxyl groups, amide groups or hydrazide. Storage-stable liquid or pasty thermoset mixtures consisting of polyisocyanates and polyols, characterized in that they have been inactivated by adding compounds containing groups. 2. A substance according to claim 1, in which, after inactivation of the surface of the polyisocyanate particles, the reactive NCO groups present in the mixture and the hydroxyl groups of the polyol are present in a ratio of 1:0.5 to 0.5:1. blend. 3 Storage-stable liquids at room temperature consisting of polyisocyanates and polyols, optionally containing additives such as protective colloids, inert solvents, softeners, pigments, fillers, dyes or other auxiliaries customary in coatings technology. or in pasty thermoset mixtures, the polyisocyanate has a particle diameter of 0.1 to 150μ.
m, optionally dispersed in a polyol containing the abovementioned additives, and the surface of the polyisocyanate particles is inertized, with the total amount of isocyanate groups present being deactivated.
0.01 to 0.499 equivalent % are inactivated by primary or secondary amines or water, or 0.01 to 20 equivalent % of the total isocyanate groups present are carboxyl groups, phenolic hydroxyl groups, amide groups or hydrazide. A process for producing a storage-stable liquid or pasty thermoset mixture of a polyisocyanate and a polyol, which has been inactivated by adding a compound containing groups, in which the polyisocyanate is dispersed in the polyol. and storage-stable liquids or pastes consisting of polyisocyanates and polyols, characterized in that the deactivating agent is already contained in the polyol or is added at least partially afterwards to the dispersion of the polyisocyanate in the polyol. Process for producing thermoset mixtures. 4 Storage-stable liquids at room temperature, consisting of polyisocyanates and polyols, optionally containing additives such as protective colloids, inert solvents, softeners, pigments, fillers, pigments or other auxiliaries customary in coating technology. or in pasty thermoset mixtures, the polyisocyanate has a particle diameter of 0.1 to 150μ.
m, optionally dispersed in a polyol containing the abovementioned additives, and the surface of the polyisocyanate particles is inertized, with the total amount of isocyanate groups present being deactivated.
0.01 to 0.499 equivalent % are inactivated by primary or secondary amines or water, or 0.01 to 20 equivalent % of the total isocyanate groups present are carboxyl groups, phenolic hydroxyl groups, amide groups or hydrazide. In a process for producing storage-stable liquid or pasty thermoset mixtures of polyisocyanates and polyols which have been deactivated by adding compounds containing groups, the polyisocyanates are first treated with a deactivating agent. and then dispersed in a polyol,
Process for producing storage-stable liquid or pasty thermoset mixtures consisting of polyisocyanates and polyols. 5 Storage-stable liquids at room temperature consisting of polyisocyanates and polyols, optionally containing additives such as protective colloids, inert solvents, softeners, pigments, fillers, dyes or other auxiliaries customary in coatings technology. or in pasty thermoset mixtures, the polyisocyanate has a particle diameter of 0.1 to 150μ.
m, optionally dispersed in a polyol containing the abovementioned additives, and the surface of the polyisocyanate particles is inertized, with the total amount of isocyanate groups present being deactivated.
0.01 to 0.499 equivalent % are inactivated by primary or secondary amines or water, or 0.01 to 20 equivalent % of the total isocyanate groups present are carboxyl groups, phenolic hydroxyl groups, amide groups or hydrazide. 1. The use of storage-stable liquid or pasty thermoset mixtures of polyisocyanates and polyols, which have been inactivated by the addition of group-containing compounds, as automotive underseal materials.