Alkylalkoxysilyl-1,3-oxazolines, a method of production and use

Alkylalkoxysilyl-1,3-oxazolines, their production by reacting 2-alkenyl!-1,3-oxazolines with alkylalkoxysilanes or cyano alkylene silane compounds with amino alcohols and the use of the compounds for modifying materials with siliceous surfaces.

FIELD OF THE INVENTION 
This invention relates to alkylalkoxysilyl-1,3-oxazolines and methods of 
producing the same. More particularly, it relates to a siliceous materials 
having a surface that is modified with these oxazoline compounds and 
methods for producing the modified siliceous materials, as well as 
plastics containing the modified siliceous materials and a process for 
producing them. 
BACKGROUND OF THE INVENTION 
In the past, fillers have been added to plastics to improve the properties 
of plastics. According to U.S. Pat. No. 4,868,226, fillers for improving 
polyethylene resins included organic or inorganic fillers, for example, 
silica. The filler according to that invention could also be subject to 
surface treatment in order to keep a balance between rigidity and impact 
strength of the polyethylene. For example, organosilane compounds were 
used as surface treating agents for fillers which were then added to 
polypropylene resins. 
SUMMARY OF THE INVENTION 
One object of the invention is to improve the properties of plastics, such 
as tensile strength. Material having siliceous surfaces can be modified 
with novel compounds according to the invention which then can be added to 
plastics such as polypropylene. 
Thus, an object of the invention is to provide compounds and modified 
materials having siliceous surfaces modified by these compounds. A further 
object of the invention is to provide the method for making the compounds 
and for modifying materials having siliceous surfaces with the compounds. 
Another object is to provide plastic resins having improved properties, 
and which contain the modified siliceous materials and a method for 
producing the same. 
Accordingly, the compounds and methods in accordance with the invention are 
compounds which are alkylalkoxysilyl-1,3-oxazolines of the general formula 
##STR1## 
wherein R is a member selected from the group consisting of alkyl with 1 
to 6 C atoms, branched or unbranched, alkoxy with 1 to 4 C atoms, and 
phenyl wherein Si is bonded to at least one alkoxy group; and wherein x 
signifies a whole number from 2 to 14. 
A method of producing the alkylalkoxysilyl-1,3-oxazolines as defined above 
comprises reacting 2-(alkenyl)-1,3-oxazoline of the general formula 
##STR2## 
wherein x is a whole number of 2 to 14 with an alkylalkoxysilane of the 
general formula 
##STR3## 
wherein R is a member selected from the group consisting of branched or 
unbranched alkyl having 1-6 carbon atoms, alkoxy having 1-4 carbon atoms, 
or phenyl, wherein the 2-(alkenyl)-1,3-oxazoline and alkylalkoxy silane is 
reacted in the presence of a Pt or rhodium catalyst. 
A method of producing the alkylalkoxysilyl-1,3-oxazolines as defined above 
can also be achieved by reacting an amino alcohol with a cyanosilane 
compound of the general formula 
##STR4## 
wherein R is a member selected from the group consisting of branched or 
unbranched alkyl having 1-6 carbon atoms, alkoxy having 1-4 carbon atoms, 
or phenyl, and y is a whole number from 2 to 12. The 
2-(alkenyl)-1,3-oxazoline and alkylalkoxy silane is reacted in the 
presence of a Pt or rhodium catalyst. The amino alcohol and the 
cyanosilane compound is reacted in the presence of a Cd salt acting as 
catalyst. 
A modified siliceous material comprises alkylalkoxysilyl-1,3-oxazolines and 
a material having a siliceous surface. The alkylalkoxysilyl-1,3-oxazolines 
is bonded to the siliceous surface of the material to form a modified 
siliceous material. 
A method for producing modified siliceous material comprises reacting the 
alkylalkoxysilyl-1,3-oxazolines with hydroxyl groups on the siliceous 
surface of a material to form a modified material with the general formula 
##STR5## 
Plastics according to the invention can be made by adding the modified 
siliceous material which comprises the alkylalkoxysilyl-1,3-oxazolines to 
the plastics.

DETAILED DESCRIPTION OF THE INVENTION 
The compounds in accordance with the invention have the general formula 
##STR6## 
in which R signifies alkyl with 1 to 6 C atoms, branched or unbranched, 
alkoxy with 1 to 4 C atoms, phenyl and Si is substituted by at least one 
alkoxy group, and x signifies a whole number of 2 to 14. 
The invention also has as subject matter a method of producing the 
alkoxysilyl oxazolines according to claim 1, characterized in that a 
2-(alkenyl)-1,3-oxazoline of the general formula 
##STR7## 
in which x has the meaning given above is reacted in the presence of a Pt 
or rhodium catalyst with an alkylalkoxysilane of the general formula 
##STR8## 
in which R has the same meanings as above. 
It is preferable to use triethoxy- or trimethoxysilane. 
The reaction takes place at temperatures from 80.degree. to 140.degree. C., 
optionally under the pressure adjusted by the vapor pressure of the 
reactants and solvents at these temperatures and optionally under 
protective gas. 
In general, the particular initial oxazoline compound is used as solvent. 
However, it is just as possible to work using inert, organic solvents 
which dissolve the reactants. 
The alkenyl-1,3-oxazoline and the silane to be used are used in a molar 
ratio of 1:1 to 2.0:1, especially 1.2:1 to 1.7:1. 
The hydrosilylation catalysts are known from the state of the art. 
Hexachloroplatinic acid or coordination complexes such as e.g. 
RhCl(PPh.sub.3).sub.3, optionally in the presence of peroxidic compounds, 
are suitable. 
In a further variation of the method, the compounds in accordance with the 
invention are produced by a method which is characterized in that a 
cyanosilane compound of the general formula 
##STR9## 
in which R has the meaning given above and y is a whole number from 2 to 
12 is reacted with 2-aminoethanol in the presence of a Cd salt acting as 
catalyst, optionally under protective gas. 
The reaction generally takes place at a temperature of from 60.degree. to 
140.degree. C., optionally under the pressure being produced at these 
temperatures by the vapor pressure of the components of the reaction 
mixture. The cyanosilane compound and the 2-aminoethanol are generally 
used in a molar ratio of 1.2:1 to 1:1.2. Soluble cadmium salts in a molar 
amount of 0.1 to 3% relative to the amount of cyanosilane compound are 
used as catalyst. An inert, organic compound, especially alcohols with 1 
to 4 C atoms, branched or unbranched, are selected as solvent. The danger 
of re-esterification to a homogeneity as regards the substituents in 
formula IV must naturally be watched for. 
The compounds of the invention are used in the modification of siliceous 
surfaces. This includes, e.g. surfaces of glass fibers, glass spheres, 
balls, or pellets and also precipitated silicas with a specific surface of 
5 to 800 m.sup.2 /g or pyrogenically obtained silicas with correspondingly 
high surfaces like those known for the reinforcement of plastics. Methods 
for the modification of siliceous surfaces can be obtained from the state 
of the art. It is customary e.g. in the case of glass fibers to immerse 
these materials in the corresponding, appropriate solutions of the 
organosilane compounds and to spray with a solution or the pure product. 
In the case of fine fillers a spraying of the powder with simultaneous 
intensive mixing has also proven itself. 
The concentrations of the silyl-1,3-oxazolines used fluctuate between 0.01 
and 15 parts by weight relative to the material to be modified. 
The reaction with the OH groups located on the surface of these materials 
take place e.g. according to the following scheme: 
##STR10## 
This reaction preferably takes place under alkaline catalysis, that is, in 
the presence of e.g. ammonium compounds soluble in the system or of 
further amines. 
The glass fibers, glass spheres, silicas, etc. modified in accordance with 
the invention are used in plastics preferably containing double bonds such 
as e.g. polypropylene. Carboxylated types in which e.g. the following 
coupling mechanism is observed are particularly suitable: 
##STR11## 
If glass spheres modified with the compounds of the invention are used e.g. 
in carboxylated propylene the maximum tensile stress of the non-filled 
matrix theoretically possible is achieved. In contrast thereto, materials 
treated with octyl silane exhibit a significantly reduced tensile stress. 
EXAMPLES 
1. Synthesis of alkylalkoxysilyl oxazolines 
Production of 2-10-triethoxysilyl)decyl!-1,3-oxazoline and 
2-10-(trimethoxysilyl)decyl!-1,3-oxazoline 
##STR12## 
1.1 Example 1 
Production of 2-10-(triethoxysilyl)decyl!-1,3-oxazoline 
A mixture of 
34.3 g (0.163 mole) 2-(9-decenyl)-1,3-oxazoline, 
17.9 g (0.109 mole) triethoxysilane, 
0.2 g (0.22 mmole) Rh.sup.1 Cl (PPh.sub.3).sub.3, and 
0.29 ml (0.87 mmole) t-butylhydroperoxide (3M solution in toluene) 
was heated for 1 h to 100.degree. C. in a round-bottomed flask with 
internal thermometer and inlet tube for protective gas. The fractionated 
vacuum distillation of the batch yielded 33.5 g (82% of theory) 
2-10-(triethoxysilyl)decyl!-1,3-oxazoline at a boiling point of 
148.degree.-150.degree. C. (0.1 mbar). 
FTIR (KBr): .nu.=2920, 1669 (C.dbd.N), 1105, 950 (oxazoline) 
cm.sup.-1..sup.1 H NMR (300 Mhz, CDCl.sub.3): .delta.=0.63 (2H,t,J=7.9 
Hz), 1.21 (23H,m) 1.64 (2H,m), 2.22 (2H,t,J=7.0 Hz), 380 (8H,m), 4.17 
(2H,t,J=9.4 Hz). .sup.13 C NMR (75 Mhz, CDCl.sub.3): .delta.=10.2, 18.1, 
22.6, 25.8, 27.8, 29.1, 29.1, 29.2, 29.2, 29.3, 33.0, 54.2, 58.1, 66.9, 
168.5 C.sub.19 H.sub.39 NO.sub.4 Si calc. C 61.08 H 10.52 N 3.75 (373.57) 
obs. 60.88 10.58 3.80 MS (EL): m/z=373 (M.sup.+, 10), 85 (100), 98 (72) 
HRMS: m/z calc. For C.sub.19 H.sub.39 NO.sub.4 Si 373.2648, obs. 373.2654 
1.2 Example 2 
Production of 2-10-(trimethoxysilyl)decyl!-1,3-oxazoline 
A mixture of 
3.95 g (18.9 mmoles) 2-(9-decenyl)-1,3-oxazoline, 
1.92 g (15.7 mmoles) trimethoxysilane, 
0.18 ml ((0.008 mmoles) H.sub.2 PtCl.sub.6.aq (0.044M in diglyme) 
was heated in a round-bottomed flask with internal thermometer and inlet 
tube for protective gas for 15 h to 100.degree. C. The fractionated vacuum 
distillation of the batch yielded 2.1 g (41% of theory) 
2-10-(trimethoxysilyl)decyl!-1,3-oxazoline at a boiling point of 
133-135.degree. C. (0.1 mbar). 
IR(KBr): .nu.=2920, 1668, 1110, 950 cm.sup.-1 .sup.1 H NMR (300 Mhz, 
CDCl.sub.3): .delta.=0.61 (2H,t,J=7.9 Hz), 1.23 (14H,m), 1.68 (2H,m), 2.23 
(2H,t,J=7.0 Hz), 3.48 (9H,s), 3.78 (2H,t,J=9.4 Hz), 4.17 (2H,t,J=9.4 Hz) 
.sup.13 C NMR (75 Mhz, CDCl.sub.3): .delta.=9.0, 22.4, 25.8, 27.8, 29.1, 
29.1, 29.1, 29.3, 29.3, 32.9, 50.3, 54.2, 66.9, 168.5 C.sub.16 H.sub.33 
NO.sub.4 Si calc. C 57.97 H 10.03 N 4.22 (331.53) obs. 58.14 9.82 4.22 MS 
(EL): m/z=331 (M.sup.+, 12), 85 (100), 98 (92) HRMS: m/z calc. for 
C.sub.16 H.sub.33 NO.sub.4 Si 331.2179, obs. 331.2186. 
1.3 Example 3 
Production of 2-3-(triethoxysilyl)propyl!-1,3-oxazoline 
##STR13## 
A mixture of 50 ml ethanol abs. water-free, 
2.5 ml (11.2 mmoles) 3-cyanopropyltriethoxysilane, 
0.67 ml (11.2 mmoles) 2-aminoethanol, and 
0.12 g (0.22 mmoles) cadmium acetate dihydrate 
was heated for 20 h until reflux in a round-bottomed flask with reflux 
condenser and inlet tube for protective gas. 
The 2-3-(triethoxysilyl)propyl!-1,3-oxazoline was produced in 25% 
conversion. IR (KBr): .nu.=2920, 1668, 1110, 950 cm.sup.-1 1 H-NMR: 4.15, 
3.80 ppm (oxazoline) 
2. Modification of surfaces 
2.1 Example 1 
A suspension of 
700 ml methanol, 
70 ml water (deionized), 
15 ml ammonium hydroxide solution (25% by weight-in water), 
10 g Aerosil.RTM. 200, pyrogenically produced SiO.sub.2, spec. surface 200 
m.sup.2 /g 
3.85 g (10.3 mmoles) 2-10-triethoxysilyl)decyl!-1,3-oxazoline 
was heated for 2 h to an internal temperature of 50.degree. C. in a 
round-bottomed flask with internal thermometer and reflux condenser. The 
filtered-off SiO.sub.2 was subsequently dried 4 h at 30.degree. C./oil 
pump vacuum, then 2 h at 80.degree. C./oil pump vacuum. 
IR (KBr): .nu.=2927, 2855, 1641 (C=N) cm.sup.-1 Thermogravimetry 
(25.degree.-700.degree. C.): 10.1% by weight (48 mmoles decyloxazoline/100 
g Aerosil 200) Elementary analysis: 44 mmoles/100 g Aerosil 200 .sup.29 
Si-CP-MAS-NMR: -60 ppm T.sub.2 -64 ppm T.sub.3 +T.sub.4. 
2.2 Example 2 
A suspension of 
300 ml toluene abs. water-free, 
10.0 g Aerosil.RTM. 200, pyrogenically produced SiO.sub.2, 
11.2 g (30 mmoles) 2-10-triethoxysilyl)decyl!-1,3-oxazoline 
was heated for 2 h to an internal temperature of 50.degree. C. in an 
agitated flask with internal thermometer and reflux cooler. The 
filtered-off SiO.sub.2 was subsequently dried 4 h at 30.degree. C./oil 
pump vacuum, then 2 h at 80.degree. C./oil pump vacuum. 
IR (KBr): .nu.=2927, 2855, 1641 (C=N) cm.sup.-1 Thermogravimetry 
(25.degree.-700.degree. C.):4.6% by weight (22 mmoles decyloxazoline/100 g 
Aerosil 200) Elementary analysis: 21 mmoles/100 g Aerosil 200 .sup.29 
Si-CP-MAS-NMR: 55 ppm (standard TMS) T.sub.1 -59 ppm T.sub.2. 
2.3 Example 3 
The work was carried out analogously to the method in example 2 with an 
amine catalyst wherein 
300 ml toluene abs. water-free, 
10.0 g Aerosil 200, 
11.2 g (30 mmoles) 2-10-(triethoxysilyl)decyl!-1,3-oxazoline, and 
1.1 ml (10 mmoles) benzylamine 
was heated for 48 h until reflux. The filtered-off SiO.sub.2 was 
subsequently extracted 24 h with toluene, then dried in an oil pump vacuum 
at 60.degree. C. for 5 h. 
IR (KBR): .nu.=2926, 2855, 1640 (C=N) cm.sup.-1 Thermogravimetry 
(25.degree.-700.degree. C.): 6.5% by weight (31 mmoles decyloxazoline/100 
g Aerosil 200) Elementary analysis: 30 mmoles/100 g Aerosil 200 .sup.29 
Si-CP-MASNMR: -59.5 ppm T.sub.2 -63.5 T.sub.3 +T.sub.4. 
2.4 Example 4 
A suspension of 
700 ml methanol, 
70 ml water (deionized), 
15 ml ammonium hydroxide solution (25% by weight in water), 
100 glass spheres CP 5000-00, 
3.85 g (10.3 mmoles) 2-10-(triethoxysilyl)decyl!-1,3-oxazoline 
was heated for 2 h to an internal temperature of 50.degree. C. in a 
round-bottomed flask with internal thermometer and reflux condenser. The 
filtered-off SiO.sub.2 was subsequently dried 4 h at 30.degree. C./oil 
pump vacuum, then 2 h at 80.degree. C./oil pump vacuum. 
Thermogravimetry (25.degree.-650.degree. C.): 0.20% by weight (0.95 mmole 
decyloxazoline/100 g glass bulbs). Manufacturer of the glass spheres: 
Potters Ballotini, Kirchheim-Bollanden Type: CP 5000-00 untreated, 
non-silanized average dimension 5-10 .mu.m, 99%&lt;12 .mu.m 
3. The use of the modified materials 
Two series with three types of glass spheres were tested. In the Series I 
experiments, the amount of filler was varied at a constant adhesion 
promoter content (10% by volume). In the Series II experiments, the amount 
of adhesion promoter was varied at a constant filler content (10% by 
volume). The adhesion promoter used in the following examples is 
carboxylated polypropylene and the fillers are glass spheres as further 
described below. 
The composites were produced in a Haake Rheomix 90 kneader with a 60 ml 
Zweihaken mixing chamber at 60 rpm and 240.degree. C. with a total 
reaction time of six minutes. The components were mixed in varying 
percentage by volume amounts. After the reaction the material obtained was 
melt-pressed to plates 2 mm thick from which specimens were milled 
according to DIN for stress-strain measurements. 
The maximum tensile stress theoretically possible of the non-filled matrix 
is achieved in the composite obtained by the covalent bonding of the 
carboxylated PP on oxazoline-functionalized micro-glass spheres. By way of 
comparison the glass spheres coated with octylsilane, which differ 
structurally only by the lack of oxazoline, and the untreated glass 
spheres have considerably reduced tensile stresses (table and graph 1). 
Matrix polypropylene: PPn; Shell KM 6100 Adhesion promoter PP-COOH, 
Polybond BP Chemicals, acrylic acid (6% by weight) grafted PP, M.sub.W 
=30000-40000 Filler glass spheres: Potters Ballotini CP 50000-00, d.sub.99 
=12 .mu.m 
a) Untreated 
b) Silanized with oxazolinyldecyltriethoxysilane, 0.95 mmole/100 g 
c) Silanized with octyltriethoxysilane, 1.0 mmole/100 g 
##STR14## 
3.2 Series I: PPn+10% by volume PP-COOH+x % by volume (0, 10, 20, 30) 
glass a), b), c) 
TABLE 1 
______________________________________ 
Glass % by 
E-modulus Tensile Elongation 
Type vol. (Mpa) stress (Mpa) 
at tear 
______________________________________ 
-- 0 1230 30.0 20 
a) 10 1490 29.0 10 
b) 10 1510 34.0 9 
c) 10 1510 28.1 38 
a) 20 1770 27.0 4 
b) 20 1940 34.0 8 
c) 20 1890 22.2 44 
a) 30 2490 25.8 4 
b) 30 2440 33.6 4 
c) 30 2261 18.4 24 
______________________________________ 
See FIG. 1 for a graph of these results. 
3.3 Series II: PPn+x % by volume (0, 1, 2, 5, 10) PP-COOH+10% by volume 
glass a), b) 
TABLE 2 
______________________________________ 
PP-COOH 
% by E-modulus Tensile stress 
Elongation at 
Type vol. (Mpa) (Mpa) tear 
______________________________________ 
a) 0 1340 26.7 380 
b) 0 1380 28.2 60 
a) 1 1430 27.0 40 
b) 1 1430 29.7 33 
a) 2 1440 27.7 18 
b) 2 1530 30.5 12 
a) 5 1540 28.0 13 
b) 5 1490 32.5 15 
a) 10 1490 29.0 10 
b) 10 1510 34.0 9 
______________________________________ 
See FIG. 2 for a graph of these results 
Further variations and modifications of the foregoing will be apparent to 
those skilled in the art and are intended to be encompassed by the claims, 
appended hereto. 
German priority application 196 06 413.9 is relied on and incorporated 
herein by reference.