DE938933C - Process for the production of crosslinked, highly elastic products - Google Patents

Description

It is known, hydroxyl-containing linear Saturated polyester by reaction with diisocyanates in high molecular weight, rubber-elastic products convict. So it succeeds z. B., very weakly branched adipic acid glycol polyester, each of which 25. The glycol molecule is replaced by a trifunctional alcohol, such as trimethylolpropane, through conversion to be converted into highly elastic, crosslinked products with diisocyanates. The small structure is a disadvantage and the very undesirable property of going into the hardened state on storage.

Other processes to produce very high-quality rubber-elastic products by polyaddition are based Then, hydroxyl-containing linear polyesters initially somewhat with an excess of diisocyanates to extend. The polyesters, which now contain diisocyanate groups, are then treated with glycols and diamines etc. aftertreated, so that in this way first an extension of the polyester and attached to it then crosslinking takes place via urethane or urea groups.

Further possibilities for the production of elastic products are to use linear hydroxyl-containing saturated polyesters with an excess of diisocyanates slightly exceeding the OH numbers to extend. When heated to 100 ° for a longer period of time, those at the ends react Isocyanate groups with crosslinking. However, such products have a greater permanent elongation and also harden after short storage at room temperature.

Mixtures of, in particular, linear saturated hydroxyl groups are used according to the invention and unsaturated polyesters with a den

O Η groups either equivalent or with one up to about 30% excess amount of a diisocyanate expediently in the heat for the reaction brought. The polymerization of the unsaturated polyesters can be carried out by adding polymerization accelerators, such as peroxides, after they have fully reacted with the diisocyanates. While the diisocyanates initially an extension of the Bring about polyester, then a crosslinking of the polyester chains occurs mainly through Free radical or heat polymerization of the double bonds. It is beneficial to have the proportion of the unsaturated ester to the saturated one should be kept small, otherwise the mechanical Values can occur. It is also of some importance to use such unsaturated polyesters; which contain only small amounts of unsaturated groups.

The saturated polyester is used in the

ao the main ones that have aliphatic components contain, such as adipic acid, succinic acid, glycol, diglycol. Mixed polyesters can of course also be used use which, in addition to the aliphatic components, also aromatic ones, such as phthalic acid.

contain. However, such esters give the end products a more or less leather-like appearance Appearance and go only at elevated temperature

into the elastic state. ·

As unsaturated polyesters containing hydroxyl groups, those have also proven to be particularly favorable which are composed of aliphatic components and which are produced by thermal condensation from dicarboxylic acids such as adipic acid, succinic acid with maleic acid and glycols are! Aromatic ones in particular have proven useful as diisocyanates, such as i, 5-naphthylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate.

The manufacture of the new materials will be like

is carried out as follows: The mixture of saturated and unsaturated polyesters is after dehydration in a vacuum at elevated temperature with the OH numbers corresponding or something added excess amount of a diisocyanate and poured into molds after a short reaction time.

Then another 15 to 20 hours at reheated about 100 °.

The highly elastic materials obtained in this way have a very low permanent elongation and show no tendency to change into the hardened state when stored in space. The rest of them too mechanical properties are excellent.

Examples
A. Preparation of the saturated polyester

146 parts of adipic acid and 68; Parts of glycol are gradually heated to 210 ° while passing nitrogen over them. From 130 ⁰ , esterification occurs with elimination of water. If the temperature of the transition thermometer falls below 80 °, a vacuum is gradually applied. After about a further 8 hours at 14 mm and 200 to 210 °, the vacuum esterification is interrupted. The acid number of the polyester is 1.8 and the OH number 56. The mixture is stirred well throughout the esterification. ■ '

B. Making an Unsaturated Polyester

740 parts of adipic acid, 98 parts of maleic anhydride and 415 parts of glycol are heated under vigorous stirring and passing nitrogen over gradually to 210 ^0th From about 140 ⁰ the esterification begins and water distills over. When the transition temperature has dropped to 80 °, a vacuum is carefully applied until 14 mm are reached. When the acid number has fallen to 2, the esterification is interrupted. The OH number is then 56. After some time, the ester solidifies to form a light yellow wax.

example 1

200 parts of the saturated polyester A and 30 parts of the unsaturated polyester B are first dehydrated 30 minutes at 130 ⁰ in vacuo of 20mm.unter stirring. Is then added to 1,5-naphthylene at 130 ⁰ 26 parts, the temperature is allowed to increase to 140 ⁰ and then fall back to 125 ° by itself. It is beneficial to apply a vacuum during the isocyanate reaction in order to free the melt from air bubbles. After removing the vacuum, it is poured into molds and heated at 100 ° for 20 hours. The result is a highly elastic casting with the following mechanical properties: 1. Thickness 0.52 cm; 2. Tensile strength 217 kg / cm ² , elongation at break 694%; 3. Permanent elongation after 1 minute 8, after 1 hour 5; 4. Shore hardness 57, elasticity 59; 5. Structure ring sample 38.8 kg, elongation 440%.

Example 2

200 parts of polyester A, 50 parts of unsaturated polyester B and 28.7 parts of 1,5-naphthylene diisocyanate are processed according to Example 1. The casting has the following mechanical properties: 1. Thickness 0.52 cm; 2. Tensile strength 205 kg / cm ² , elongation at break 682%; 3. Permanent elongation after 1 minute 8, • after ι hour 5; 4. Shore hardness 58, elasticity 56; 5. Structure ring sample 37.8 kg, elongation 457%.

Example 3. ^

200 parts of polyester A, 70 parts of the unsaturated polyester B and 30.9 parts of 1,5-naphthylene diisocyanate are reacted according to Example 1. The casting has the following mechanical properties: i. Thickness 0.58 cm; 2. Tensile strength 190 kg / cm ² , elongation at break 689%; 3. Permanent elongation after ι minute 7, after 1 hour 4; 4, Shore hardness 56, elasticity 55; 5. Structure ring weight 37.7 kg, elongation 459%

Example 4

■

. 200 parts of polyester A, 50 parts of unsaturated polyester B and 26.5 parts of 1,5-naphthylene diisocyanate are reacted as described in Example 1 and then heated at 100 ° for 20 hours. The mechanical properties are as follows: 1. Thickness read; 0.4 cm; 2. Tensile strength 294 kg / cm ^2,. Elongation at break [

nung 86ο%; 3 · Permanent stretching after ι minute 15, after ι hour 7; 4. Shore hardness 51, elasticity 56; 5. Structure ring sample 17.5 kg, elongation 490%.

Example 5

200 parts of polyester A, 90 parts of polyester B and 30.5 parts of 1,5-naphthylene diisocyanate will be processed according to the information in Example 1. Before pouring into the molding, 3 parts are placed

to di-tert-butyl peroxide and heated to 110 ° for 15 hours. The cast body has the following mechanical values: 1. Thickness 0.55 cm; 2. Tensile strength 216 kg / cm ² , elongation at break 800 ° / ₀ ; 3. Permanent elongation after ι minute 8, after 1 hour 4; 4. Shore hardness 49, elasticity 56; 5. Structure ring sample 22.9 kg, elongation 500%.

Claims (4)

PATENT CLAIMS: i. Process for the production of crosslinked, highly elastic Products, characterized in that mixtures of saturated and unsaturated im essentially linear polyester containing hydroxyl groups with diisocyanates in the Heat and / or reacted in the presence of polymerization accelerators will. 2. The method according to claim 1, characterized in that that such unsaturated polyester are used, which consists of mixtures of unsaturated and saturated dicarboxylic acids are produced. 3. The method according to claim 1 and 2, characterized in that the used for the reaction Amounts of diisocyanates are equivalent to the OH groups of the polyester. 4. The method according to claim 1 and 2, characterized in that the diisocyanates up to Excess of 30% over the amount required for reaction with the free hydroxyl groups be applied. 1 509 642 2.