Nonaqueous plastics formulations

PA0 A) 100 parts by weight of at least one finely divided plastic which consists of PA1 a) from 30 to 100% by weight of methyl methacrylate (monomer I), PA1 b) from 0 to 70% by weight of an acrylate of a C.sub.1 -C.sub.8 alkanol or of a methacrylate of a C.sub.2 -C.sub.8 -alkanol or of a mixture of these monomers (monomers II), PA1 c) from 0 to 15% by weight of an .alpha.,.beta.-monoethylenically unsaturated mono- and/or dicarboxylic acid of 3 to 5 carbon atoms (monomers III), PA1 d) from 0 to 20% by weight of copolymerizable monomers which contain at least one nitrogen base group and/or one hyroxyl group (monomers IV) and PA1 e) from 0 to 5% by weight of other copolymerizable monomers (monomers V), in polymerized form, PA0 B) from 30 to 300 parts by weight of at least one polymer which consists of PA1 a) from 5 to 100% by weight of glycidyl acrylate and/or methacrylate (monomers VI), PA1 b) from 0 to 95% by weight of an acrylate or methacrylate of a C.sub.1 -C.sub.8 -alkanol or of a mixture of these monomers (monomers VII) and PA1 c) from 0 to 30% by weight of other copolymerizable monomers (monomers VIII), in polymerized form, PA0 C) from 0 to 300 parts by weight of one or more inert fillers and PA0 D) from 0 to 50 parts by weight of one or more adhesion-improviding agents.

The present invention relates to nonaqueous plastics formulations, 
essentially containing 
A) 100 parts by weight of at least one finely divided plastic which 
consists of 
a) from 30 to 100% by weight of methyl methacrylate (monomer I), 
b) from 0 to 70% by weight of an acrylate of a C.sub.1 -C.sub.8 -alkanol or 
of a methacrylate of a C.sub.2 -C.sub.8 -alkanol or of a mixture of these 
monomers (monomers II), 
c) from 0 to 15% by weight of an .alpha.,.beta.-monoethylenically 
unsaturated mono- and/or dicarboxylic acid of 3 to 5 carbon atoms 
(monomers III), 
d) from 0 to 20% by weight of copolymerizable monomers which contain at 
least one nitrogen base group and/or one hydroxyl group (monomers IV) and 
e) from 0 to 5% by weight of other copolymerizable monomers (monomers V), 
in polymerized form, 
B) from 30 to 300 parts by weight of at least one polymer which consists of 
a) from 5 to 100% by weight of glycidyl acrylate and/or methacrylate 
(monomers VI), 
b) from 0 to 95% by weight of an acrylate or methacrylate of a C.sub.1 
-C.sub.8 -alkanol or of a mixture of these monomers (monomers VII) and 
c) from 0 to 30% by weight of other copolymerizable monomers (monomers 
VIII), in polymerized form, 
C) from 0 to 300 parts by weight of one or more inert fillers and 
D) from b 0 to 50 parts by weight of one or more adhesion-improving agents. 
The present invention furthermore relates to the use of these formulations 
as adhesive, sealing and coating materials. 
DE-B 24 54 235 discloses nonaqueous plastics formulations which contain, as 
base polymers, finely divided homopolymers of methyl methacrylate or 
copolymers of this monomer with C.sub.1 -C.sub.10 -alkyl acrylates and/or 
C.sub.2 -C.sub.10 -alkyl methacrylates and, as an organic liquid, 
phthalates, phosphoric esters, glycolates, high-boiling alkylaryl 
hydrocarbons or ether compounds. These plastics formulations have the 
properties of plastisols, ie. they behave like a pasty, relatively easily 
brushable dispersion in the cold state but gel to form a viscous 
rubber-like material when heated. Because of this property, the plastisols 
are used as adhesive, sealing and coating materials. DE-B 24 54 235 and 
DE-B 25 29 732 furthermore disclose that the adhesive power of these 
plastics materials can be improved by copolymerizing in the base polymers 
minor amounts of monomers having free carboxyl, hydroxyl, epoxide, amino 
or heterocyclic groups containing at least one N atom in the ring, and/or 
by adding suitable adhesion promoters to these plastics materials, but the 
adhesive power of these plastics materials are also not completely 
satisfactory in the solidified state on metallic substrates. 
It is an object of the present invention to overcome this disadvantage by 
means of more suitable nonaqueous plastics formulations. 
We have found that this object is achieved by the plastics formulations 
described at the outset, which are in the form of plastisols. 
Suitable finely divided plastics A) are both homopolymers and copolymers of 
methyl methacrylate. Preferably used copolymers are those which are 
composed of from 50 to 90% by weight of methyl methacrylate. Particularly 
suitable comonomers are the monomers II, the esters of acrylic or 
methacrylic acid which are derived from the alkanols ethanol, isopropanol, 
n-butanol, isobutanol, n-hexanol and 2-ethylhexanol and, in the case of 
acrylic acid, from methanol being preferably copolymerized. Particularly 
preferred monomers II are methyl acrylate, ethyl acrylate and 2-ethylhexyl 
acrylate. 
Component A) advantageously also contains, as copolymerized units, the 
monomers III and IV which carry free functional groups. Preferred monomers 
III are acrylic, methacrylic and itaconic acid, of which methacrylic acid 
is particularly preferred. Advantageously incorporated monomers IV are the 
nitriles and the amides of acrylic and methacrylic acid and the esters of 
these acids with lower aliphatic hydroxy- or aminoalcohols, such as 
hydroxyethyl acrylate, hydroxyethyl methacrylate and 
N,N-dimethylaminoethyl acrylate. Other suitable monomers IV are vinyl 
compounds which contain a heterocyclic group having at least one basic 
nitrogen atom in the ring, such as N- or C-vinyl compounds of imidazole, 
N-vinylimidazole being particularly preferred. 
In addition, component A) may contain minor amounts, ie. up to 5% by 
weight, of other copolymerizable monomers, such as vinyl esters of C.sub. 
-C.sub.4 -alkanoic acids. 
The finely divided polymers A) are preferably prepared by free radical 
polymerization, suspension and emulsion polymerization being preferred to 
solution, mass and precipitation polymerization. An aqueous plastics 
dispersion whose solids content is usually from 30 to 60% by weight is 
prepared in a particularly advantageous manner by polymerization of the 
relevant monomers in an aqueous medium under the known conditions of 
emulsion polymerization in the presence of water-soluble free radical 
initiators and emulsifiers and in the presence or absence of protective 
colloids and regulators and further assistants. 
The dispersion obtained is then converted into a dry powder in a 
conventional manner, for example by spray drying, precipitation or freeze 
drying. The spray drying process is usually preferred in the case of 
polymers having a glass transition temperature (Tg) above 20.degree. C., 
while precipitation or freeze drying is advantageous in the case of 
polymers having a Tg of less than 20.degree. C. By subsequent addition of 
suitable assistants, such as finely divided silica, the resulting polymer 
particles can be prevented from sticking to one another in the case of 
relatively low glass transition temperatures. 
Component A) having a mean particle size of from 0.05 to 500 .mu.m 
(arithmetic mean of the maximum particle diameters), preferably from 0.1 
to 20 .mu.m, particularly preferably from 0.5 to 10 .mu.m, is 
advantageously used. The desired particle size can be controlled by the 
amount and type of emulsifier, the plastics particles being larger the 
smaller the amount of emulsifier. 
In general, from 1 to 5% by weight, based on the amount of monomers used, 
of emulsifier are employed. 
Emulsifiers which have proven particularly useful are ethoxylated 
alkylphenols (degree of ethoxylation: 3-30, C.sub.6 -C.sub.10 -alkyl 
radical) and/or ethoxylated fatty alcohols (degree of ethoxylation: 5-50, 
C.sub.8 -C.sub.25 -alkyl radical), both of which may be sulfated, and the 
alkali metal salts of the sulfated derivatives. 
Particularly suitable water-soluble polymerization initiators are 
peroxydisulfates, such as ammonium or sodium peroxydisulfate, or combined 
systems which contain an organic reducing agent and a peroxide, for 
example formaldehyde sodium sulfoxylate/hydrogen peroxide. Polymers A) 
which are mainly used are those which have a K value of from 20 to 130, 
preferably from 30 to 100, in tetrahydrofuran. The K value is a relative 
viscosity number which is determined similarly to DIN 53,726 at 25.degree. 
C. Here, the flow velocity of a solution of 0.1 g of polymer per ml of 
tetrahydrofuran (THF) is measured relative to the flow velocity of pure 
THF. It characterizes the mean degree of polymerization of the polymer, 
which can be influenced by controlling the polymerization conditions in a 
known manner. The polymerization temperature is preferably from 70.degree. 
to 90.degree. C. 
In accordance with the definition, suitable solvating components B) are 
polymers which contain the esters of glycidol with acrylic or methacrylic 
acid in pure or mixed form. The monomers VII, in an amount of not more 
than 95% by weight, may be present as further monomers in B), the esters 
of acrylic acid or methacrylic acid which are derived from the alkanols 
methanol, ethanol, n-butanol or 2-ethylhexanol preferably being 
copolymerized. Component B) may furthermore contain other copolymerizable 
monomers, such as acrylonitrile, methacrylonitrile, vinyl esters of lower 
alkanoic acids, the esters of acrylic or methacrylic acid with lower 
aliphatic hydroxyalcohols and styrene, in amounts of not more than 30% by 
weight. 
Of particular interest are polymers B) which contain the esters of glycidol 
with acrylic or methacrylic acid in amounts of from 20 to 60% by weight. 
The amount of the monomers VII is preferably from 30 to 80% by weight. The 
K value of B) in THF should be from 8 to 30, preferably from 8 to 18. 
The preparation is advantageously carried out in a conventional manner by 
free radical polymerization of the particular monomers in the absence of a 
solvent or in solution, in the presence of mercapto-containing molecular 
weight regulators, such as 2-mercaptoethanol, ethanethiol, dodecanethiol, 
thiophenol, thioglycerol or esters of thioglycollic acid. Preferred 
solvents are aromatic hydrocarbons, such as toluene or xylenes. In 
general, polymerization is carried out with refluxing of the solvent. 
Initiators which have proven particularly useful are organic peroxides, 
such as tert-butyl perbenzoate or dilauryl peroxide. The unconverted 
monomers and, where relevant, the solvent are separated off from the 
liquid polymers after polymerization is complete, for example by 
evaporation under reduced pressure. 
In addition to the obligatory components A) and B), fillers C) and 
adhesion-improving agents D) may be added as assistants to the novel 
plastics formulations. 
The fillers serve primarily for increasing the viscosity and improving the 
abrasion resistance. Examples of suitable fillers are aluminum silicates, 
quartz, precipitated or pyrogenic silica, gypsum, barite, talc, dolomite, 
calcium carbonate, carbon black and color-imparting pigments. In general, 
the fillers are added in a finely divided form. The mean particle size, as 
the arithmetic mean of the maximum diameters in each case, is preferably 
from 0.5 to 200 .mu.m. As a rule, however, filler-free plastics 
formulations are preferred. 
Examples of adhesion-improving agents D) are triethylene glycol 
dimethacrylate and trimethylol trimethacrylate in combination with 
peroxides, and liquid or solid phenol or resorcinol resins having a low 
formaldehyde content and aminosilanes or polybasic carboxylic acids, such 
as maleic acid or itaconic acid. The novel plastics formulations may 
additionally contain minor amounts of viscosity regulators, suspending 
agents, flow improvers, fragrance materials, wetting agents or other 
assistants usually used in coating technology. 
The ready-to-use formulations are advantageously prepared from the various 
components A) to D) and, if required, further assistants by stirring the 
other starting components into the liquid component B). The resulting 
nonaqueous plastics formulations are liquid to pasty plastisols which 
solidify on heating. Depending on the composition of the plastics 
formulations, temperatures of from 60.degree. to 240.degree. C. are 
required for this purpose. The required solidification time is from 2 
minutes to 2 hours. Usually, plastics formulations which contain 
components A) having a low Tg require relatively low solidification 
temperatures and short solidification times, while components A) having a 
high Tg require high solidification temperatures and long solidification 
times. As a rule, an increase in the adhesive power is also observed with 
increasing solidification. At room temperature, curing of the novel 
plastics formulations usually occurs so slowly that as a rule the shelf 
life is sufficient for practical applications. The two essential 
components A) and B) are readily compatible with one another, ie. the 
gelled plastisols are usually homogeneous materials from which there is 
virtually no exudation of the component B) (blotting paper test). 
The novel plastisols have high adhesive power in the gelled state, 
particularly on metallic substrates, and are preferably used as adhesive, 
sealing and coating materials. They are particularly suitable for 
adhesively bonding and coating metals and are advantageously employed as 
underbody protection and for sealing weld seams in the automotive sector. 
Another typical use is the impregnating and coating of textile fabrics, 
floor coverings or substrates of imitation leather. The plastics 
formulations can be applied, for example, by means of a trowel or brush, 
by spraying on with a paint gun or by knife coating, calendering, casting 
or immersion. The heat required for curing can be supplied, for example, 
by means of hot air or by exposure to infrared radiation.