CS212015B1 - Method of hydrolysis of the acryloxyalkyltrialkoxysilanes - Google Patents

Description

The invention relates to a process for the hydrolysis of acryloxyalkyltrialkoxysilanes.

In order to improve the adhesion of the plastics to the various inorganic substrates, whether in the form of fibers, beads, foil, pulp, fabrics, etc., the phase interface is adjusted by various binding means, also called propyl adhesion promoters. Industrially, the most widely used method is to apply adhesion promoters from aqueous systems, warheads because the use of organic solvents is limited, either because of their toxicity, flammability and, last but not least, for economic reasons.

As adhesion promoters, especially for unsaturated polyester resins, various acryloxyalkyltrialkoxysilanes are used. These are used in the formulation of lubricants, binders and the like. based on water, they convert into water-soluble silanols, most often under the catalytic action of water-soluble organic acids, mainly acetic acid (Noll W .: Chemie und Technologie der Silikone, Verlag Chemie 1968). Although ¹ skutočnústi known that a number of silanols, especially silane triol is characterized Malop stability, this problem gave little attention in applications adhesion promoters.

Disadvantages associated with the presence of known homogeneous catalysts were eliminated by the solution according to ČS cars. lighting. no. 183,491, which uses a heterogeneous catalyst, ion exchanger, and hydrolysis, is performed in a single-phase system using organic water-soluble solvents. A certain disadvantage of this method is that silane hydrolysates often cause their coagulation in the formulation of some aqueous latex compositions due to the organic solvents used in the hydrolysis of silanes. Advancement of these known methods has been achieved by the application of adhesion promoters in the form of emulsions, which are described in CS aut. axis. no. 187,720 and 195,225. While using these emulsions, although coagulation of the latex is removed, they are also not universally used. We have found that the presence of the epoxy resins as well as the phthalic acid esters used in the preparation of the emulsions together with the unsaturated trialkoxysilanes increases the flexibility of the latex coating used. Although this property is welcome for a variety of glass fiber applications, these emulsions are not suitable for the preparation of glass fibers. of hard direct lubricants. The described disadvantages of these solutions are overcome by the method according to the invention.

The present invention provides a process for the hydrolysis of acryloxyalkylthio-alkoxysilanes of the general formula

Rx

I

CH ₂ = CCO- (CH 2) _n -Si (OR ₂ ) 3 O wherein R 1 is hydrogen or methyl, R ₂ is methyl or ethyl and an integer of 1 to 3. The principle of the invention is that the hydrolysis is carried out in water in the presence of dihydrophosphates of the general formula

MH ₂ PO ₄ wherein M is NH ₄ , Na or JK, in an amount of at least 0.04 to 5 moles of dihydrophosphate per mole of silane. , '

Hydrolysis can be carried out in various apparatuses equipped with agitators, mixers, rolling mills and the like. In the case of low speed stirrer devices or the use of devices with limited circulation circulation, a uniform distribution of the silane emulsion can be achieved by adding to the water various substances which reduce the surface tension of the water by 0.02 to 2% by weight. A wide variety of known surfactants can be used for this purpose. These are mainly different alkyl polyglycol ethers, copolymers based on ethylene oxide and propylene oxide, sorbitol esters and their polyoxyethylene derivatives and the like, which, in the case of glass fiber treatment, also serve as lubricants in the lubricants. In this way, the injection area of the silane is increased by forming a fine emulsion with water and a catalyst, which results in an increased rate of hydrolysis.

The silane hydrolysates of the present invention can be used to formulate hard, direct latex lubricants for treating glass fibers. Their use also increases the stability of aqueous silane solutions, which allows to prepare larger disposable quantities of lubricant compositions! and to reduce the concentration of adhesion promoters, which is not only economical but also hygienic, as the fiber treatment workers come into direct contact with the lubricating compositions. They are particularly advantageous in the preparation of lubricants which contain, in addition to unsaturated silanes, aminosilanes as binding agents. In use, the mechanical properties of the lamirates are better than that of using acetic acid as a catalyst, which reacts with aminosllan to the corresponding amide when firing the fibers, thus reducing its reactivity.

In addition to these applications, silane hydrolysates can be used to treat different powder fillers for reinforcing plastics, especially unsaturated polyester resins, e.g. in the formulation of prepreg compositions.

The invention is readily illustrated by way of examples.

Example 1: '

1 g of oxyethylated nonylphenol-based surfactant with 9 moles of ethylene oxide and ammonium dihydrophosphate was dissolved in 200 ml of water. To this solution was added 5 g of 3-methacryloxypropyltrimethoxysilane with stirring. The amount of ammonium dihydrophosphate and the time of hydrolysis in minutes are shown in the table.

NH ₄ H ₂ PO ₄ (g) hydrolysis (min)

0.1 20  0.3 15 0.5 10 2.3 5 4.6 5 7.0 5 10.0 5

Hydrolysis of the silane under the same conditions in the absence of catalyst did not proceed in 2 hours. The prepared silane solutions are stable and no precipitation of polysiloxial agglomerates was observed even after 20 hours. The hydrolysis method was used to prepare the lubrication shown in the table.

lubrication A ^B 1 C (° / w / w) polyvinyl acetate dispersion (50%) 6 '6 6 3-metakryloxypropyl- trimethoxysilane 0.2 0.2 0.2 dihydrogen ammonium 0.1 0 0 dibutyl phthalate 0 0.2 0 epoxy resin 0 0 0.2 emulsifier 0 0.05 0.05 lithium chloride 0.2 0.2 .0,2 lubricant, aminoamide 0.05 0.05 0.05 Water - - up to 100%

Lubrication B was prepared according to the CS cars procedure. The prepared lubricants A, B, C were used to treat a 15 micron diameter glass fiber directly after the platinum oven outlet. They were fired for 4 h at 125 [deg.] C. The stiffness of the fiber, which is characterized by its overhang, was using A 13.5 cm, B 12.5 cm and C 12 cm using the lubrication.

Example 2:

3 g of ammonium dihydrophosphate were dissolved in 200 ml of water. 5 g of 3-acryloxypropyltrimethoxysilane was added to the solution with stirring. Hydrolysis was performed in 15 minutes.

Example 3:

Similar to Example 1, only 3 g of potassium dihydrogen phosphate was used as catalyst. Hydrolysis was performed in 30 minutes.

Example 4:

Similar to Example 1, only 3 g of sodium dihydrogen phosphate was used as catalyst. Hydrolysis was performed in 30 minutes.

Example 5:

1 g of a surfactant prepared by reacting 85 moles of propylene oxide to 1 mol of trimethylolpropane was dissolved in 200 ml of water, followed by addition of 36 moles of ethylene oxide [hydroxyl number 40 mg KOH (g)]. To the solution was added ammonium dihydrophosphate, 3 g and 5 g methacryloxymethyltriethoxysilane. Hydrolysis was performed in 20 minutes.

subject

Claims (2)

INVENTION A process for the hydrolysis of acryloxyalkyltrialkoxysilanes of the general formula ri _CH2-C-C-O- (CH ₂₎ n Si (OR _{2) 3} Wherein R 1 is hydrogen or methyl, R ₂ is methyl or ethyl and an integer of 1 to 3, characterized in that the hydrolysis is carried out in water in the presence of dihydrophosphates of the general formula MH ₂ PO ₄ wherein M is NH ₄ , Na or K in an amount of 0.04 to 5 moles of dihydrophosphate per mole of silane. 2. Hydrolysis method according to claim 1, characterized in that the water contains substances which reduce the surface tension of the water, preferably nonionic surfactants in an amount of 0.02 to 2% by weight.