DE1520022C3 - Process for the production of sulfur-containing epoxy resins modified with organic silicon compounds - Google Patents

Description

R ₆ (RO) ₀ SiMSH

(M = alkylene group with 3 to 4 carbon atoms, R _h and R '= any hydrocarbon radicals, α and b = any number from 0 to 3, a + b - 3).

3. The method according to claim 1, characterized in that there is used as the mercaptoalkyl groups Silicon compounds those of the general formula

R _n (OR ^ Si (MSH) ₁₁ O ₂ n + m + v

(n = any number from 0 to 2.999, m = 0 to 2, υ = any number from 0.0001 to 1, preferably from 0.01 to 1, η + m + υ = 1 to 3).

4. The method according to any one of claims 1 to 3, characterized in that the reaction carries out in the presence of an amine.

Sulfur-free epoxy resin precursors are already modified with organic silicon compounds been. There are a number of valuable improvements in properties, especially the Thermal stability, can observe.

The production of sulfur-containing epoxy resins modified with silicon-containing compounds was however, this is not possible without further ado, since the corresponding output connections are either not available stood or only in a cumbersome way, and d. H. uneconomical, were available.

A process has now been found which modifies the production of the desired organosilicon Epoxy resins permitted in a simple manner.

What is claimed is a process for the production of sulfur-containing epoxy resins modified with organic silicon compounds by reacting organosilicon compounds with epoxy resin precursors, optionally in the presence of solvents and / or at elevated temperature, which is characterized in that the organosilicon compounds used are silicon compounds containing mercaptoalkyl groups.
It has proven particularly advantageous if the silicon compounds containing mercaptoalkyl groups are those of the general formula

R ₆ (RO) ₀ SiMSH

where M is an alkylene group having 3 to 4 carbon atoms, R ₆ and R 'are any hydrocarbon radicals, α and b is any number from 0 to 3, the sum of which is 3, can be used.

Another preferred embodiment of the method according to the invention is that as Silicon compounds containing mercaptoalkyl groups are those of the general formula

R "(OR ') _m Si (MSH)" O. n + m + v

40

High molecular weight epoxy resin precursors containing sulfur are already known, which as a rule produced by reacting di- or polyepoxide compounds with such sulfur compounds which carry at least one reactive hydrogen atom on the sulfur atom. Suitable Sulfur-containing reaction components are z. B. hydrogen sulfide, saturated or unsaturated aliphatic Dithiols with 2 to 16 carbon atoms, heterocyclic polythiols, which differ from furan, di- or tetrahydrofuran, Derive pyran or di- or tetrahydropyran. Those under the designation are also suitable Thiokol commercially available high molecular weight polymercaptans.

In particular, higher molecular weight compounds are used as epoxy components, such as they can be obtained by reacting bisphenols or polyhydric alcohols.

A detailed description of such compounds can be found in the book »Chemische Technology of plastics, epoxy compounds and epoxy resins «(Springer Verlag 1958).

The products obtained are characterized by improved heat resistance, flexibility and low Shrinkage from. They are suitable for the production of lighter corrosion-resistant pipes and are used alongside their use as a metal adhesive used in particular for embedding electrical device parts.

in which R, R 'and M have the above meanings, η is any number from 0 to 2.999 and m from 0 to 2, ν is any number from 0.0001 to 1, preferably from 0.01 to 1, where n + m + v is 1 to 3 can be used.

Such compounds have become available in a smooth reaction and with high yields, in accordance with German patent specification 1,163,818. The radicals R and R 'can, for example, have the meaning of a methyl, ethyl, isoamyl, hexyl, phenyl or a benzyl radical. M is preferably the - (CH ₂ ) ₃ group.

One advantage of the process according to the invention is that the reaction takes place at room temperatures or only moderately elevated temperatures can be undertaken.

However, it can sometimes be useful to work at elevated temperatures in order to increase the solubility of the products in each other or to accelerate their implementation.

The reaction can also be accelerated by having the reaction in the presence a catalyst is carried out, amines in particular having proven useful for this.

Examples of suitable amines are piperidine, ethylmorpholine, Benzyldimethylamine, diethylamine, triethylamine, dimethylaminopropionitrile, pyridine, diethylenetriamine, Triethylenetetramine, tris (dimethylaminomethyl) phenol and m-phenylenediamine.

From this exemplary list it can be seen that those known per se are also effective as hardeners Amines able to catalyze the reaction.

As a rule, the silicon compounds containing mercaptoalkyl groups are used in such amounts in order that an epoxy group corresponds to at most one mercapto group. However, it has been shown that with an excess of mercapto groups, based on epoxy groups, the adhesiveness of the Process products on metal surfaces increase. Among other things, this results in its special suitability such connections for metal bonding.

If the epoxy resin precursor to be modified has an excess of epoxy groups, based on Mercapto groups, one obtains products which at a later point in time by means of one of the per se known hardeners can be cured.

In this way it is e.g. B. possible, liquid or heat-flowable silicon-modified sulfur-containing Manufacture epoxy resin products that cure at the point of use in due course can be. Such products have a pot life, which they use to fill joints and the like. make usable.

Since the products manufactured according to the process have an increased chemical and, in particular, solvent resistance have, they are suitable, among other things, as casting compounds for sealing joints of containers for solvents.

By modifying with the organosilicon compounds described above, it also improves the electrical properties of the epoxy resins. In particular, the improved To name insulation properties. With regard to the increased solvent resistance at the same time, they are Particularly suitable as casting or investment compounds for electrical device parts, which are used in chemical Industry can be used.

The dielectric properties of the process products are also compared to the silicon-free, sulfur-containing ones Improved epoxy resins. The process products can still be used before curing Fillers, e.g. B. mica, are added.

It is particularly advantageous that the silicon-modified epoxy resins have an increased temperature resistance exhibit. The process according to the invention is to be explained in more detail with the aid of the following examples will.

The preparation of the organosilicon compounds containing mercapto groups can be carried out accordingly the German patent specification 1163 818 take place. The starting compounds required for the experiments can be made as follows:

Production of y-mercaptopropylmethylsiloxane (I)

136.5 g (1 mol) of γ-chloropropylmethylsiloxane, 79.8 g (1.05 mol) of thiourea, 7.5 g of sodium iodide and 150 ml of ethanol are refluxed for 15 hours in an oxygen-free nitrogen atmosphere, while stirring. 204 g (3 mol) of 25% aqueous NH _{3 are} added to the reaction product in the cold and the separated Ulphase is heated to boiling twice with 200 ml of water and separated off again, the second amount of water being added to the second amount of water to improve the phase separation. The oil obtained is dried azeotropically with toluene.

Another method of preparation is that 150 g (0.72MoI) γ-mercaptopropylmethyldiethoxysilane Stirred with 300 g of 1% hydrochloric acid and then 250 ml of an alcohol-water mixture distilled off. The residue is neutralized with sodium bicarbonate solution in a rotary evaporator freed from water under reduced pressure at 150 ° C. and filtered.

Making a siloxane of the average formula

OSi (CH ₃ ), CH ₃ OSi (CH ₃ ) ₃ (CH ₃ ) ₃ - -O — Si — O— Si — O— Si-O-Si (CH ₃ ) ₃ C ₆ H ₅ (CH ₂ ) ₃ C ₆ H ₅ SH -Si-

(Π)

A mixture of 347 g (1.66 mol) of γ-mercaptopropylmethyldiethoxysilane, 144.7 g (1.33 mol) of trimethylchlorosilane and 141 g (0.66 mol) of phenyltrichlorosilane is stirred into 1200 g of 4% strength hydrochloric acid over the course of 30 minutes. Thereafter, the mixture is heated ^{to 100 ° C. for 1 hour.} The oil phase is separated off and dried over calcium chloride / potassium carbonate. The filtered product is freed from small amounts of low-boiling constituents at 100 ° C. in a water jet vacuum. This gives 400 g (95.8% of theory) of Siloxanöles a viscosity of 44.2 cP (at 2O ⁰ C). The SH content is 12.7% (theoretically 13.2%).

60 Production of a siloxane
the average formula

CH ₃ CH ₃ -ο- QH ₅ SiO - Si - > 3 Si-O- CH ₃ (CH ₂ O SH Si (CH ₃ ),

(III)

A mixture of 64.6 g (0.5 mol) of dimethyldichlorosilane, 54.3 g (0.5 mole) trimethylchlorosilane, 105.8 g

(0.5 mol) phenyltrichlorosilane and 95.8 g (0.5 mol) γ-Chloropropylmethyldichlorosilane is brought to -10 ° C cooled down. Then 43.2 g (2.4 mol) of water are added dropwise with stirring over the course of 1 hour. From the The escaping hydrogen chloride becomes the entrained silane components in a cold trap cooled to - 70 ° C removed and fed back to the hydrolysis vessel. Then with aqueous sodium bicarbonate solution neutralized, the water finally removed in a rotary evaporator in vacuo, the oil obtained filtered and mixed with 45.6 g (0.6MoI) thiourea, 7.1 g Sodium iodide and 200 g propanol are added. This mixture is made in an oxygen-free nitrogen atmosphere Boiled under reflux and stirring for 40 hours. The reaction product is with ice-cooling with 102 g (1.5 mol) of 25% aqueous ammonia was stirred for 1 hour. The separated oil is separated and boiled twice with 250 ml of water each time. The last remainder of the water is added to a rotary evaporator removed under reduced pressure. The yield is 180 g (corresponding to 85.5% of theory). The product contains 6.9% sulfur (theoretically 7.6%).

The mixture with the organosilicon compound I hardens in a short time with the development of heat. For the blends with the siloxanes of formula II and III are formed gel-like to viscous products which can be cured well at 100 to 150 ⁰ C.

Manufacture of a silicon compound
the average formula

(IV)

Examples

1. The organosilicon compounds of the formula I bis prepared as described above III are mixed with epoxy resin precursors and hardener according to the following scheme:

Conversion product Diethylenetriamine Silicon of pentaerythritol organic with epichlorohydrin, connection Epoxy equivalent 1.04 ml] weight 162 1.2ml> hard resin 2 g (I) 10 g 1.26 ml j 2 g (H) 10g 2 g (HI) 10 g

2. An experiment is carried out in the same way with the following products:

Conversion product Diethylenetriamine Silicon of bisphenol A organic with epichlorohydrin, connection Epoxy equivalent 0.85 ml],. _t
very hard weight 196 ° ' ^98ml resin 2 g (I) 10 g 1.08 ml] ^mrZ 2 g (H) 10 g 2 g (IH) 10 g

The hardener was added with cooling.

3. Another experiment is carried out with tris (dimethylaminomethyl) phenol, which is commercially available as a hardener under the name DMP 30:

Organosilicon
connection Conversion product
of pentaerythritol with
Epichlorohydrin,
Epoxy equivalent weight
162 Harder
DMP 30 2 g (D.
2 g (H)
2 g (HI) 10g
10 g
10 g 0.8 g
0.8 g
0.8 g

A mixture of 114 g (0.5 mol) of bisphenol A and 104 g (0.5 mol) of γ-mercaptopropylmethyldiethoxysilane and 0.27 g of sodium methylate is heated to 150 ° C. The released ethylanol is distilled off. The last residues of ethanol are removed under reduced pressure and a heating bath temperature of 180 ° C. To Addition of 100 ml of benzene, 1.135 g of trimethylchlorosilane are added. The reaction product will filtered and then benzene was distilled off under reduced pressure. It remains a very viscous one Product of the composition shown above.

Examples

4. The compound IV thus obtained is with the epoxy resin of Example 2 or a reaction product of bisphenol A with epichlorohydrin, the a small amount of butyl glycidyl ether is added, the epoxy resin having an epoxy equivalent weight of 190 has hardened. For this purpose, 12 g of the organosilicon compound of the formula IV mixed with 48 g each of the epoxy resin precursor and 0.15 g diethylenetriamine. This mixture is 15 minutes stirred at 90 to 100 ° C and then rapidly cooled. The result is highly viscous products that remain fluid for a longer period of time. A solidification usually only takes place after months. When using the The first-mentioned epoxy resin produces a very solid resin when the second-mentioned one is used Epoxy resin is a soft resin that can be cured well at 100 ° C. Even with these resins the curing by adding suitable hardeners, such as. B. amines, also essential at room temperature accelerate.

The epoxy content of the resins is 0.3 or 0.305 equivalents per 100 g (theoretically 0.36 or 0.35 equivalents per 100 g).

5. A curable epoxy resin precursor that is flowable for a few weeks can be produced in the following ways: 40 g of the reaction product of bisphenol A with epichlorohydrin with an epoxide equivalent weight of 196, 10 g of the siloxane of the formula II and 0.125 g of diethylenetriamine are mixed and at 100 ° C stirred for about 90 minutes, resulting in a homogeneous mixture. Then the product is after Heated to 100 ° C for 2 hours. The result is a product that is liquid and curable for several weeks an epoxide content of 0.28 equivalents per 100 g (theoretical 0.34 equivalents per 100 g).

Preparation of a polymercaptan of the formula (V)

C ₂ H ₅ O

CH ₃ CH ₃ CH ₃ Ί-κ Si OC ₂ H ₅ (CH ₂ ) ₃ CH ₃ (CH ₂ ) ₃ SH I.
SH

138.7 g (0.667 mol) of γ-mercaptopropylmethyldiethoxysilane, 114 g (0.5 mol) of bisphenol A and 0.54 g of NaOCH ₃ are mixed. The ethanol formed is then distilled off with stirring up to a bath temperature of 150 ° C. A further residue of ethanol is distilled off in vacuo up to a bath temperature of 100 ° C. A total of 45.5 g of ethanol are obtained (theoretically 46 g). The product is neutralized with trimethylchlorosilane and filtered through a filter press.

Analysis:

Found ... 10.1% S;
calculated ... 10.32% S.

This corresponds to a practical SH equivalent

of 317.

Examples.

6. Hardening of the diglycid ether of bisphenol A

with the polymercaptan of the formula V without

catalyst

19.6g (0.1 epoxy equivalent) of a largely bisphenol A diglycidyl ether Diepoxids with an epoxy equivalent weight of 196 (trade name Epikote 828) and 31.7 g (0.1 SH equivalent) of the polymercaptan of the formula V are mixed and for several days at room temperature ditched. A hard, clear resin forms.

7. Implementation of the diglycid ether of bisphenol A
with mercaptosilanes without a catalyst

80 g (0.408 epoxy equivalents) of a largely bisphenol A diglycidyl ether Diepoxids with an epoxy equivalent weight of 196 (= trade name Epikote 828) and

a) 20 g (0.0962 SH equivalents) γ-mercaptopropylmethyl diethoxysilane such as

b) 20 g (0.084 SH equivalents) γ-mercaptopropyltriethoxysilane

are mixed and left to stand for one week at room temperature. The determination of the epoxy number results

a) found 0.3108, calculated 0.3118 epoxy equivalents / 100 G,

b) found 0.319, calculated 0.324 epoxy equivalents / 100 G.

The good agreement shows the quantitative conversion.

8. Implementation of the diglycid ether of bisphenol A with the y-mercaptopropylmethylsiloxane of the formula without a catalyst with the formation of a liquid, curable epoxy resin precursor

90 g (0.459 epoxy equivalents) of a largely bisphenol A diglycidyl ether

Diepoxids with an epoxy equivalent weight of 196 (trade name Epikote 828) and 10 g (0.0667 SH equivalents) of the γ-mercaptopropylmethylsiloxane of formula I (SH equivalent weight 150, theoretically 134) are stirred until a homogeneous mixture has formed. Overall leaves the reaction mixture is left to stand at room temperature for 7 days. A light and clear resin is formed, which is still flowable at room temperature and can be hardened well with the usual hardeners.

Epoxy equivalent weight:
Found 0.391 equivalents / 100 g,
calculated 0.3923 equivalents / 100 g.

The following comparative test is used to demonstrate technical progress: y-mercaptopropylmethylpolysiloxane, the production of which has been described above, serves as the one according to the invention Starting product for the comparison tests. The resistance to solvents and chemicals is examined of casting resins cured at room temperature based on γ-mercaptopropylmethylpolysiloxane or using a hardener based on amino amides, which is the standard hardener on the market is.

Recipe A

Weight jeile

Bisphenol A diglycidether 100

y-mercaptopropylmethylpolysiloxane .. 73
Tris (dimethylaminomethyl) phenol ... 2

Recipe B

Bisphenol A diglycidether 100

Commercial 100 aminoamide hardener

The resistance to solvents is determined by the decrease in pendulum hardness after storage determined under the solvents mentioned. The starting values are for hardened casting resins for recipe A 216 seconds and for cured casting resins of recipe B 160 seconds. In the The following table shows the measured pendulum hardnesses.

Recipe A 7 days Recipe B 7 days
storage solvent 24 hours storage
(Sec.) 24 hours no longer storage
(Sec.) 119 storage
(Sec.) measurable, Silo acid *) 165 16 Film ge welled and replaced

*) Silo acid is a mixture of lactic acid, butyric acid and acetic acid.

309 514/481

continuation

solvent

benzene

Xylene

Methyl isobutylicetone

Recipe A

24 hours

storage

(Sec.)

123
129

217

7 days

storage

(Sec.)

160
109

192

Recipe B

24 hours

storage

(Sec.)

28 21

29

7 days storage

22 sec. 26 sec.

21 sec.

of the state of the art based on bisphenol A diglycidether / Thiokol (Formula C) compared. Moldings according to formulation A or C are transformed into various after a storage time of 7 days at room temperature Media immersed. The percentage weight gain is used as a measure of the swelling and thus the Resistance of the bricks to the various media is determined. A little weight gain means so a good resistance. The results are summarized in the table below.

Resins according to US Pat. No. 3,055,858 or according to German Pat. No. 1,129,704 no cured films under the conditions used here. Lacquer films, made according to the German Patent Specification 1,050,065, Example 1, are significantly inferior in terms of solvent resistance than the bisphenol A diglycidether / aminoamide hardener system used here (Formulation B) according to the current state of the art.

The recipe A is also made with a system 'exposure time

1 week

5 weeks ....

water

Recipe
AC

0.50
1.15

10% HCl

Recipe
AC

1.24 0.32
2.62 0.76

1.41
9.91

■ 20%
H ₂ SO ₄

Recipe
AC

0.37
0.89

1.02

2.04

20%
NaOH

Recipe A C

0.23
0.46

The technical progress of the process according to the invention can be seen from these test results recognize.

Claims (2)

Patent claims: 1. Process for the production of sulfur-containing, modified with organic silicon compounds Epoxy resins by reacting organosilicon compounds with epoxy resin precursors, optionally in the presence of solvents and / or at elevated temperature, thereby characterized in that one is used as organosilicon compounds Silicon compounds containing mercaptoalkyl groups are used. 2. The method according to claim 1, characterized in that there is used as the mercaptoalkyl groups Silicon compounds those of the general formula