DE1133125B - Process for the production of molded parts from molding compounds which contain unsaturated polyesters and organic sulfur compounds as accelerators - Google Patents

Description

INTERNAT.KL. C 08 g

GERMAN

PATENT OFFICE

N18820IVd / 39b

REGISTRATION DATE: AUGUST 25, 1960

NOTICE
THE REGISTRATION
ANDOUTPUTE
EDITORIAL JULY 12, 1962

The invention relates to a method for producing molded parts by curing - at normal or higher temperature - of molding compounds, the unsaturated polyester, polymerizable onto it unsaturated compounds, organic peroxides as catalysts, 0.01 to 1 percent by weight organic sulfur compounds as accelerators as well as customary additives, such as dyes, Plasticizers, fillers, stabilizers and inhibitors.

In this context, an unsaturated polyester is the polycondensation product of to understand essentially dicarboxylic acids with dihydroxy compounds in which both or one of the both components consist wholly or partially of a saturated compound. The polycondensation product can by means of mono- and / or polybasic carboxylic acids and / or mono- and / or polyhydric alcohols.

The unsaturated, essentially linear condensation products are cured into infusible moldings by polymerizing suitable organic compounds. Such compounds are monomeric unsaturated organic compounds which have one or more CH ₂ = C C groups per molecule.

The curing can be carried out by heating the molding compound.

Usually, however, molding compositions are used which contain a substance which is able to initiate curing at a lower temperature. Organic peroxide compounds, which give off free radicals when decomposed, are often used for this purpose. This activates the double bonds of the unsaturated polyester and the _{compounds containing CH 2} = C <groups. However, the reaction initiated in this way is difficult to control and, in addition, heating up to the decomposition temperature of the peroxide compound is necessary if the reaction mixture is to be allowed to gel within a short time.

In this context, gelling is the transition of the molding compound from the liquid to the to understand semi-solid phase.

An excess of the peroxide compound results in very rapid gelling and great heat development. Little peroxide compound leads to long gel times.

In order to remedy these disadvantages, the molding compound is known as a peroxide compound in addition to the peroxide compound Accelerator added, which activates the peroxide compound, allowing curing at a temperature Process for the production of molded parts

from molding compounds,

the unsaturated polyester

as well as organic sulfur compounds

included as an accelerator

Applicant:

N. V. Philips' Gloeilampenfabrieken, Eindhoven (Netherlands)

Representative: Dipl.-Ing. H. Zoepke, patent attorney, Munich 5, Erhardtstr. 11

Claimed priority:

Netherlands of August 28 and December 24, 1959 (No. 242 807 and No. 246 796)

Catharinus Jacobus van Putten and Petrus Antonius van Gool, Eindhoven

(Netherlands) have been named as inventors

lower than the decomposition temperature of the peroxide compound has a satisfactory rate.

In the usual catalyst systems, e.g. B. those that contain a metal soap as an accelerator, the temperature of the reaction mixture increases very quickly when the catalyst system is chosen so that a short gel time is obtained. This temperature increase can be in in some cases more than 100 ° C. In this case, the reaction mixture hardens within a few minutes to its final stage.

The rapid hardening at elevated temperature causes the occurrence of shrinkage stresses in the Reaction product. This is particularly disadvantageous when the molding compound is used for embedding objects is used. Not only can the items be damaged, but there can also be cracks in the Product occur. This z. B. in electrical devices the correct insulation against atmospheric agents Influences lost.

The molded parts obtained in this way are also difficult to work mechanically due to their great hardness. Through this and through the existing

209 619/441

Stresses present in the material can form cracks or pieces come loose during machining.

It has also been proposed to use organic sulfur compounds such as the n-alkyl mercaptans as Use accelerator.

However, a short gel time can only be achieved with these compounds if they are used in combination with benzoyl peroxide as a catalyst. Those hardened with hooves in this combination However, resins are colored yellow. With other organic peroxides, however, they have an additional effect very sluggish.

According to the process of the invention, short gel times at low reaction temperatures are obtained Molded parts with Shore hardnesses in the order of 50 °. This is a mechanical one Editing possible in a simple way. The fully hardened moldings are colorless.

The invention thus relates to a method for producing molded parts by curing - at normal or higher temperature - of molding compounds, the unsaturated polyester, polymerizable onto it unsaturated compounds, organic peroxides as catalysts, 0.01 to 1 percent by weight organic sulfur compounds as accelerators as well as customary additives, such as dyes, Plasticizers, fillers, stabilizers and inhibitors, contain.

The method is characterized in that molding compounds are cured as organic Sulfur compounds are the esters of mercaptocarboxylic acids with a carbon chain of 1 to 6 carbon atoms contain.

The molding compositions preferably contain the esters of κ- or ^ -mercaptocarboxylic acids.

With the method according to the invention, it is possible to obtain gel times in the order of several minutes while the temperature does not usually not as 1O ⁰ C rises than about 20 ° C and more above the ambient temperature. In some cases it is even possible to allow gelation to take place without increasing the temperature.

It has also been shown that when using the method according to the invention at the same time in most Cases a discoloration of the reaction mixture is obtained. Even a distinctly yellow-colored, chlorine-containing one Unsaturated polyester provides essentially one when the process of the invention is used colorless product. This is an important advantage as there is when using the method according to the invention it is not necessary to start from very pure raw materials if a colorless product is to be manufactured.

It has also been shown that the molded parts obtained by the process according to the invention are very have good resistance to ultraviolet light, so adding an ultraviolet light stabilizer to the Product can be omitted in most cases.

ίο In the method according to the invention, for. B. the following mercapto compounds can be used as activators: the methyl, ethyl, propyl, butyl, pentyl, hexyl, isobutyl, nonyl and dodecyl esters of mercaptoacetic acid, <x- and / J-mercaptopropionic acid, <x - and yS-mercaptocarboxylic acid and <x- and / J-mercaptoheptylic acid, in which the carbon chain, in addition to the mercapto group, can also have alkyl groups such as methyl, ethyl groups, the mono- and diesters of ethanediol, propanediol, butanediol, pentanediol and hexanediol and of diethylene glycol and corresponding polyether alcohols and the esters and partial esters with polyhydric alcohols, such as glycerol and pentaerythritol with the acids mentioned.

a5 As a peroxide compound, for. B. the following organic compounds are used: methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-methane hydroperoxide, diisopropylbenzene hydroperoxide, 2,2-bis- (tert-butylperoxy) -butane, t-butyl perbenzoate, 2-4-dichlorobenzoyl peroxide, diacetyl peroxide, Lauryl peroxide.

The process according to the invention can start from any unsaturated which is customary for this purpose Polyester and thus copolymerizable compounds are used.

As polymerizable unsaturated organic compounds are, for. B. possible: styrene, divinylbenzene, Vinyl toluene, diallyl phthalate, methacrylic acid and corresponding compounds.

The molding compositions can also contain small amounts of inhibitors, such as hydroquinone.

It has been shown that the amount of esters of mercaptocarboxylic acids to be added to the Achieving a beneficial effect is within certain limits.

These limits are between about 0.01 and 1.0 percent by weight of esters of mercaptocarboxylic acids found.

Table 1
Mixture: 70 g percent by weight peroxide compound: 4 percent by weight of one

Solution of 1,3-Butylengly- 50% ig ^en Methyläthylketon-

colphthalate maleate. solution.

Ambient temperature: 30 ° C.

Mercapto compound concentration in

Maximum temperature ⁰ C

Gel time hours

Ethanediol monomercaptoacetate ..

Ethanediol dimercaptoacetate

Ethanediol dimercaptoacetate

Propanediol dimercaptoacetate

Butanediol dimercaptoacetate

Pentanediol dimercaptoacetate

* Lowest measured concentration 0.3 to 0.4

0.06

0.05

0.05
0.3 to 0.4

0.1 *

44 to 47 32

35 to 37 36

10 19

12 5 5

Table I continued

Maximum temperature

Maximum temperature

Gel time hours

Pentanediol dimercaptoacetate

Hexanediol dimercaptoacetate -

Diethylene glycol dimercaptoacetate

Glycerol dimercaptoacetate

Glycerol trimercaptoacetate

Pentacrylthritol tetramercaptoacetate

Methyl mercaptoacetate

Butyl mercaptoacetate

Isooctyl mercaptoacetate

Nonyl mercaptoacetate

Dodecyl mercaptoacetate

Ethanediol mono-a-mercaptopropionate

Ethyl a-mercaptopropionate

Ethanediol mono-ß-mercaptopropionate

Äthandi-ß-mercaptopropionate

Ethyldi-yS-mercaptopropionate

* Lowest measured concentration

For comparison may serve that in use of cobalt octoate in an amount such the gelling time is about 10 minutes and the maximum temperature during the curing reaction between 120 and 13O ⁰ C.

When using n-alkyl mercaptans, the Gel time always longer than 45 minutes.

The esters of mercaptocarboxylic acids are preferably used in the process according to the invention Accelerator in combination with hydroperoxides (general formula R - O O H, in which R is an organic Is radical) and with ketone peroxides (general formula

0.1 *
0.1 to 0.4 *

0.1 *

0.07

0.05

0.03

0.3 to 0.8
0.4 to 0.8
0.4 to 0.8
0.4 to 0.8
0.4 to 0.8

0.3
0.4 to 0.8

0.7

0.2
0.4 to 0.7

34

to 43
34

33

33V ₂

30V ₂

to 52

until 39
until 39

to 38

to 38
41

until 45
62
44

to 57

7th
6th
6th

9V ₂ 10
12th

4V ₂ 10
9

9V ₂
10
9

8V ₂
3

2V ₂
6V ₂

in Example I according to the table below by means of a 0.2 part of methyl ethyl ketone peroxide and varying amounts of glycol dimercaptoacetate cured existing catalyst system. The polymerization reaction was carried out in a thermostat at different temperatures. The gel time in minutes at different temperatures and with different amounts of ethandioldimercaptoacetate measured (see Table 2).

Table 2
Gel time in minutes

HO-C-OOH

40

in which R ₁ and R _{2 represent} organic radicals) is used.

This is because the shortest gel times are obtained with this combination.

If the ambient temperature is 20 ° C during curing, the resulting body is quite gelatinous after the molding compound has gelled. Between 25 and 40 ^° C., rubber-like molded parts which can be easily processed mechanically are obtained. At an ambient temperature higher than 45 ° C, rather hard moldings are obtained.

The hardness of the molded parts can be increased by subjecting them to a heat treatment will. At room temperature, the final hardness will only be achieved after a few months received one year.

The following example particularly relates to the use of ethandiol dimercaptoacetate as an accelerator.

•Example

⁶ 5

7 parts by weight of an unsaturated polyester (polybutylene maleate phthalate) (Ratio of maleate to phthalate 1: 1) and 3 parts by weight of styrene were as

Ethanediol
dimercapto 20 ° C Thermostat temperature 30 ° C 35 ° C 40 ° C acetate 25 ° C 63 25th 0.002 parts 17th 10.5 7th 5 0.03 teüe 16 13th 10 10 5 0.06 parts 19th 13th 11 10 7th 0.15 TeU 25th 13th 15th 12.5 10.5 0.3 tea 30th 18th 18th 16 13th 0.45 tea 22nd

At the same time, the associated maximum temperatures were measured. Below maximum temperature is in to understand in this context the maximum temperature that occurs during the curing reaction (see table 3).

Table 3
Maximum temperature in ° C

Ethanediol
dimercapto 20 ° C Thermostat temperature 30 ° C 35 ° C 40 ° C acetate 25 ° C 33 38 0.002 TeU 20th 30th 35 40 0.03 TeU 24 25th 32 36 42 0.06 TeU 24 30th 36 42 48 0.15 tea 25th 30th 40 43 48 0.3 TeU 25th 32 40 45 52 0.45 TeU 33

Claims (3)

PATENT CLAIMS: 1. Process for the production of molded parts by curing - at normal or higher temperature - of molding compounds containing unsaturated polyesters, unsaturated compounds which can be polymerized onto them, organic peroxides as catalysts, 0.01 to 1 percent by weight of organic sulfur compounds as accelerators and, where appropriate, conventional additives such as dyes , Plasticizers, fillers, stabilizers and inhibitors, characterized in that molding compositions are cured which contain the esters of mercaptocarboxylic acids with a carbon chain of 1 to 6 carbon atoms as organic sulfur compounds. 2. The method according to claim 1, characterized in that molding compounds are cured, which contain as esters of mercaptocarboxylic acids those of the «- or / 3-mercaptocarboxylic acids. 3. The method according to claim 1 and 2, characterized in that molding compounds are cured, which contain an organic hydroperoxide or ketone peroxide as a catalyst. Considered publications:
U.S. Patent No. 2466,800;
Bjorksten, "Polyesters and their Applications," New York, 1956, p. 61. 1 209-619 / 441 7.62