DE1015603B - Process for the preparation of rubbery, vulcanizable sulfochlorination products of polyolefins - Google Patents

Description

GERMAN

The high linear head-to-tail polymers of propylene with molecular weights higher than 10,000 (obtained according to Italian patents 535,712 and 537,425) are ^{either amorphous or crystalline in the temperature range between room temperature and: ΪΌ0 6} ", depending on the steric configuration of the carbon atoms The amorphous products have rubber-like properties, but are of little interest as such, since the objects made with such non-crystalline polypropylenes tend to creep if they are continuously subjected to stress.

The crystalline polypropylenes are usually not elastomers at room temperature, since they have the property - when stretched - to assume a permanent orientation. ^:

It has now been found that it is possible to greatly enhance the physical properties of polypropylenes to change and in this way its field of application expand when they are subjected to sulfochlorination.

According to the invention, such linear propylene polymers with an average molecular weight can be used higher than 10,000 in carbon tetrachloride with mixtures of chlorine and excess Sulfurous anhydride or with sulfuryl chloride in the presence of pyridine to form rubbery, vulcanizable Implement products, with temperatures between 0 and 60 ° only up to one Chlorine content of about 10% chlorosulphonated.

The vulcanization of sulfochlorinated propylenes results in products with extremely interesting properties obtain.

It is true that highly branched olefin polymers have already been subjected to sulfochlorination and are to be modified in this way Polymers with higher chlorine content of around 20 to 50% get the more practical Applications were capable.

In the sulfochlorination, e.g. B. the polyethylene, the necessary amount of chlorine is a polyethylene in one To transform rubbery product, quite high (over 18%), and those obtained in this way Rubbers have good elongations, most of which are reversible, but with a high degree of elongation Hysteresis. The elastic behavior of the vulcanized obtained from sulfochlorinated polyethylene Products is always very unfavorable.

The linear polypropylenes have never been subjected to sulfochlorination until now. Surprisingly are the sulfochlorinated polypropylenes, if they contain only small amounts of chlorine, for the production of vulcanizable rubber-like products. It has been found that only the products which contain small amounts of chlorine, high elongations

from rubbery, vulcanizable

Sulfochlorination products

of polyolefins

Applicant:

Montecatini Societä Generale

per rindustria Mineraria e Chimica,

Milan (Italy)

Representative: Dipl.-Ing. Dipl.-Chem. Dr. phil. Dr. techn.
J. Reitstötter, patent attorney, Munich 15, Haydnstr. 5

Claimed priority:
Italy 6 August 1954

Giulio Natta and Piero Pino, Milan (Italy),
have been named as inventors

and show good elastic behavior (significantly better than the behavior of the sulfochlorinated Polyethylene) and that these properties deteriorate with increasing chlorine content.

example 1

10 grams of partially crystalline, linear propylene with an average molecular weight of about 40,000 is dissolved in 400 cm ^{3 of} carbon tetrachloride; _{A mixture consisting of 3 parts of SO 2} and 1 part of Cl _{2 is allowed} to flow through the solution, which has been heated to 70 °, over a period of I ¹ A hours at a rate of 2.66 l / hour. The product obtained is precipitated with methanol, filtered, washed and finally dried under reduced pressure. It contains 5.94% chlorine and 1.39% sulfur.

The vulcanization of this product takes place in the following way:

7.5 g of the product are mixed with 30 percent by weight of PbO and 3 percent by weight of mercaptobenzothiazole; during the mixing process the temperature rises to 40 °. The mixture is heated to 150 ° for about an hour and turns into elastic rubber. The product obtained has an elongation at break of over 500% and a strength of over 5 kg / mm ² , based on the final cross-section.

■ "" '7TO «86055

10

If the product is subjected to repeated, successive stretchings under increasing and decreasing loads until elongations of about 100 to 200% are reached, it has practically very little residual elongation. The elastic behavior is very good under these conditions. After repeated stretching, it has a breaking load of about 1 kg / mm ² and an elongation at break of about 500%.

Example 2

80 g of amorphous polypropylene with an average molecular weight of 13,500 are dissolved in 1500 cm ³ CCl ₄ at 53 ° and ^{mixed with 3} pyridine as a catalyst for the sulfochlorination reaction. ^{Finally, 10 cm 3 of} SO ₂ Cl _{2 are} added dropwise to the solution within IV2 hours while the reaction vessel is simultaneously irradiated with an incandescent lamp of 200 W. The reaction is stopped after 2 hours, the polymer is precipitated by pouring the solution into excess methanol and dries in vacuum. It contains 4.6% Cl and 1.3% · S and is 0.2% with an admixture of 40% Pb. Mercaptobenzothiazole and 5% KoIophonium vulcanized in a press at 150 ° for 60 minutes. The elastic rubber obtained in this way shows the following properties:

Breaking load 0.84 kg / mm ²

Module at 200%. Elongation ... 0.36 kg / mm ²
Elongation at break 500%

Example 3

30 g of amorphous polypropylene with an average molecular weight of 13,500 are dissolved in 600 cm »C Cl ₄ at 50 °, 0.4 cm ^{3 of} pyridine are added, which acts as a catalyst for the sulfochlorination; ^{Finally, 10 om 3} SO ₂ Cl _{2 are} allowed to drip into the solution over the course of 1 hour by simultaneously irradiating the reaction vessel with a 200 W incandescent lamp. After 2 hours, the reaction is stopped and the polymer is precipitated by pouring in the excess methanol solution and drying in vacuo; it contains 10.21% Cl and 2.73% S. The vulcanization of this product is carried out as follows: 10 g are added to a rubber mill at 30%. PbO and 3% mercaptobenzothiazole mixed. The mixture is heated in a press at 140 ° for 60 minutes and turns into an elastic rubber with the following properties:

Breaking load 1.15 kg / mm ²

Module at 200% elongation ... 0.45 kg / mm ²
Elongation at break 453%

Claims (1)

PATENT CLAIM: Process for the preparation of rubbery vulcanizable sulfochlorination products of polyolefins by reaction in carbon tetrachloride with mixtures of chlorine and excess sulfurous anhydride or with sulfuryl chloride in the presence of pyridine, thereby characterized in that one linear propylene polymers with average molecular weight higher than 10,000 at a temperature between 0 and 60 ° up to a chlorine content of about 10% chlorosulfonated. Considered publications:
German Patent No. 890 867;
U.S. Patents Nos. 2,212,786, 2,640,048: © 709696/365 9 ·.