RU2450028C2 - Method of preparing dicyclopentadiene-based two-component system - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing a dicyclopentadiene (DCPD) based two-component system for producing a homopolymer - polycyclopentadiene. The system consists of a component A containing DCPD, an organotin or aluminium activator, a moderator - ether or ester and high- or low-unsaturated rubber, and a component B containing DCPD, a tungsten-based catalyst, compound which increases catalyst solubility - alcohol or phenol, a Lewis base or a chelating agent - nitriles, ethers or acetates and high- or low-unsaturated rubber. Component B is obtained by adding a compound which increases catalyst solubility to the catalyst solution, followed by blowing hydrogen chloride, adding a Lewis base or chelating agent to the solution and adding the obtained catalyst solution to the solution of high- or low-unsaturated rubber in DCPD. When preparing component A, the activator is first dissolved in hexane or nefras, and before adding to the solution of rubber in DCPD, a moderator is first added to the latter in such an amount that molar ratio of the moderator to the activator is equal to (1-10):1.

EFFECT: longer storage life of components of the system and improved strength properties of the homopolymer, reduced amount of residual monomer in poly-DCPD and reduced water-absorption thereof.

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Description

The invention relates to the preparation of a two-component system based on dicyclopentadiene (DCPD), intended to produce a thermosetting homopolymer - polydicyclopentadiene (poly-DCPD), which can be used for the manufacture of molded parts in the automotive industry, as well as in construction and light industry.

A two-component system consists of component A containing an activator and component B containing a catalyst. When these components are mixed in a reaction injection molding machine, a solid insoluble polymer is formed that takes on the appropriate shape. The pre-prepared components A and B must be stable when stored in a nitrogen atmosphere, react when mixed for 3-5 minutes, and the homopolymer obtained on their basis must have a high flash point and have a high Izod impact strength, high tensile strength and elongation in tension, low water absorption and linear shrinkage. All these requirements are related to the direction of use of the obtained homopolymers.

Known two-component system for producing a thermosetting polymer DCPD (US patent No. 4400340, IPC B21F 1/08, C08F 4/78, publ. 1983). It includes a catalyst - tungsten hexachloride or tungsten oxytetrachloride, an activator - a tetraalkyltin or organoaluminum compound and a moderator - ethers, ketones, nitriles and polar cycloolefins. This system is used by mixing two streams, one of which contains an activator and a moderator, the other a catalyst, and one of them or both contain DCPD. These streams from the mixing device are injected into the appropriate form, where the formation of the DCPD homopolymer takes place. This system has several disadvantages associated with the low solubility of the catalyst and the possibility of premature polymerization of DCPD in its presence.

Closest to the proposed method is a two-component system for producing impact-resistant poly-DCPD, which uses a catalyst — tungsten hexachloride or tungsten oxytetrachloride, a Lewis base or a chelating agent — nitriles or ethers, acetylacetone and alkylacetoacetates, a phenolic compound or alcohol to increase the solubility of the catalyst , the solvent for the catalyst is benzene or substituted benzenes, the activator is a trialkyltin or organoaluminum compound and the moderator is iso saw ether, dibutyl ether, phenylethyl acetate and others (US patent No. 4469809, IPC C08F 4/62, publ. 1983). The main disadvantage of this method is the short storage time of the component containing the activator, a high level of residual monomer in the thermoset polymer, insufficiently high strength properties and a high rate of water absorption.

The objective of the invention is the creation of a two-component system using a tungsten-containing catalyst to obtain impact-resistant poly-DCPD with a long shelf life of components and high strength characteristics obtained on the basis of this homopolymer system.

The problem is solved by implementing a method of preparing a two-component system based on dicyclopentadiene (DCPD), to obtain a thermosetting homopolymer - polycyclopentadiene, consisting of component A containing DCPD, an activator — aluminum or organotin, a moderator — simple or complex ether, and high- or rubber low-saturated, and component B containing DCPD, a tungsten-based catalyst, a compound that increases the solubility of the catalyst — alcohol or phenol, a Lewis base or a chelating agent - nitriles, ethers or acetates and a high or low unsaturated rubber, in which component B is obtained by adding a catalyst that increases the solubility of the catalyst to the catalyst solution, followed by blowing off hydrogen chloride, introducing a Lewis base or chelating agent into the solution and adding the resulting catalyst solution to the solution with a high - or low-saturated rubber in DCPD, while in the preparation of component A, the activator is pre-dissolved in hexane or nephras and before it is introduced into the rubber solution DCPD in the last moderator initially introduced in an amount such that the molar ratio of moderator / activator was (1-10): 1.

The technical result when using the proposed two-component system is to increase the shelf life of system components and increase the strength properties of the obtained homopolymer. At the same time, the amount of residual monomer in poly-DCPD is significantly reduced and its water absorption is reduced.

The technical result is achieved due to the fact that in the preparation of component A, the activator is pre-dissolved in hexane or nephras and before it is introduced into the rubber solution in the DCPD, the moderator is initially introduced into the latter in such an amount that the moderator / activator molar ratio is (1-10): one.

Component A of the proposed two-component system has a composition, parts by weight:

DCPD 90-98 Rubber 3-7 Activator (in nephras or hexane solution) 0.6-1.5 Moderator 0.3-5

In this case, high molecular weight ethylene propylene rubber containing ethylidene norbornene (ENB) or dicyclopentadiene (DCPD) (low unsaturated) or divinyl rubber (highly unsaturated) is used as an elastomer. As the activator, organoaluminum compounds are used, in particular ethyl aluminum sesquichloride, triisobutyl aluminum or an organotin compound, for example tetraethyl tin. As a moderator, for example, MTBE or ethyl propionic acid can be used.

Component B of the proposed two-component system has a composition, parts by weight:

DCPD 90-98 Rubber 3-7 Catalyst (in toluene solution) 0.15-0.3 Lewis base or chelating agent 0.04 Enhancing compound catalyst solubility 0.04-0.1

In this case, high molecular weight ethylene propylene rubber containing ethylidene norbornene (ENB), or dicyclopentadiene (DCPD), or divinyl rubber is used as the elastomer. Compounds containing tungsten, such as WCl ₆ or WClO ₄ , are used as a catalyst. As a catalyst solubility enhancing compound, for example, nonylphenol or dodecyl alcohol is used, for example, ethyl acetate or diisopropyl ether (Lewis bases) or benzonitrile (chelating agent) are used as a Lewis base or a chelating agent.

In this case, the rubber content in the solution of DCPD selected 3-7% wt.

The amount of tungsten-containing compound is selected based on the molar ratio of DCPD / WCl ₆ - (1000-4000): 1, the Lewis base or chelating agent is used in the molar ratio of WCl ₆ / Lewis 1: (1-3). The compound that increases the solubility of the catalyst is present in an amount of 1-3 mol per 1 mol of catalyst.

The content of the activator is determined by the molar ratio of DCPD / activator - (250-500): 1. The moderator is taken in such an amount that the moderator / activator molar ratio is (1-10): 1.

Among the essential features characterizing the proposed two-component system, the distinguishing ones are:

- preliminary dissolution of the activator in nefras or hexane;

- the introduction of a moderator (for example, MTBE or ethyl ester of propionic acid) in a rubber solution in DCPD before adding an activator in hexane or nefras in such an amount that the moderator / activator molar ratio is (1-10): 1.

The method is demonstrated by the following examples.

Examples 1-3 (prototype). A 0.1 M catalyst solution was prepared by adding 1.55 g of WCl ₆ in 37.8 cm ^{3 of} dry toluene in a nitrogen atmosphere. Then 0.85 g of nonylphenol is added to the solution. The resulting solution was purged with nitrogen for several hours to remove Hcl resulting from the reaction of WCl ₆ with nonylphenol. Add 0.38 cm ³ ethyl acetate in a nitrogen atmosphere. To obtain component B, 0.5 cm ^{3 of the} obtained 0.1 M solution of WC16 is added to 10 cm ^{3 of a} 6% solution of SKEPT in DCPD. Component A is prepared as follows: in a nitrogen atmosphere of 10 cm ^{3 of a} 6% solution of CLEPT in DCPD, 0.15 cm ^{3 of} AECC is dissolved, and then 0.44 cm ^{3 of} MTBE is added to the solution. Component A and component B immediately after preparation (example 1) or after storage for 2 (example 2) or 10 (example 3) days are mixed in a 1: 1 ratio in the head of the injection molding machine. The polymerization process is carried out at a temperature of 50-70 ° C.

After a short induction period, a sharp release of heat is observed. The result is a solid, insoluble polymer, which is subjected to analysis for the content of residual monomer, strength characteristics and water absorption. The data are given in the table.

Examples 4-6. The experiments are carried out as in examples 1-3, except that component A is prepared as follows: in a nitrogen atmosphere in 10 cm ^{3 of a} 6% solution of SKEPT in DCPD, 0.44 cm ^{3 of} MTBE are dissolved, 0.15 cm ^{3 of} EAC is dissolved in 2 cm ^{3 of} hexane and this solution is mixed with a solution of SKEPTa in DCPD. Component A and component B immediately after preparation (example 4) or after storage for 2 (example 5) or 10 (example 6) days are mixed in a 1: 1 ratio in the head of a reaction injection molding machine.

Examples 7-10. The experiments are carried out as in example 6, except that the amount of MTBE added to the solution of SKEPT in DCPD is 0.085 cm ³ (example 7), 0.17 cm ³ (example 8), 1.7 cm ³ (example 9) 2.55 cm ³ (example 10).

Example 11. The experiment is carried out as in example 6, except that as an activator in the preparation of component A, tetraethyltin is used in an amount of 0.28 cm ³ .

Example 12. The experiment is carried out as in example 6, except that ethyl propionic acid in an amount of 0.5 cm ^{3 is} used as a moderator in the preparation of component A.

Example 13. The experiment is carried out as in example 6, except that in the preparation of components A and B use highly unsaturated rubber SKDN (divinyl synthetic rubber obtained on a neodymium catalyst).

Example 14. The experiment is carried out as in example 6, except that in the preparation of component B, benzonitrile in an amount of 0.44 cm ³ is used as a chelating agent.

Example 15. The experiment is carried out as in example 6, except that in the preparation of component B, diisopropyl ether in the amount of 0.43 cm ^{3 is} used as the Lewis base.

Example 16. The experiment is carried out as in example 6, except that in the preparation of component B, dodecyl alcohol in an amount of 0.72 g is used as a compound that increases the solubility of the catalyst.

Example 17. The experiment is carried out as in example 6, except that in the preparation of component A, triisobutylaluminum in an amount of 0.24 cm ^{3 is} used as an activator, and diphenyl ether in an amount of 0.85 cm ³ is used as a moderator.

From the data of the table it can be seen that with the method of preparing a two-component system based on DCPD in accordance with the prototype, the storage time of the components is less than 10 days, after 10 days the polymerization reaction does not start, and after 2 days of storage the reaction time is significantly increased, and the material obtained poly-DCPD has a lower tensile strength, elongation in tension and Izod impact strength, i.e. those indicators that are most important when using poly-DCPD for the manufacture of automotive parts. Moreover, the polymer has an increased rate of water absorption and a residual monomer content.

When implementing the inventive method, after storage for 10 days, components A and B retain their activity, and the poly-DCPD obtained on their basis has a high tensile strength, relative elongation under tension and Izod impact strength. Significantly reduced the rate of water absorption and residual monomer content. The optimal moderator / activator ratio is (1-10): 1. By reducing this ratio (example 7), the reaction time increases, the residual monomer content in the poly-DCPD increases, and the water absorption rate deteriorates significantly. By increasing the ratio (example 10), the reaction time is significantly reduced, and this can lead to irregularities on the surface of the parts.

Claims (1)

A method of preparing a two-component system based on dicyclopentadiene (DCPD) to obtain a thermosetting homopolymer - polycyclopentadiene, consisting of component A containing DCPD, the activator is an aluminum or organotin compound, the moderator is ether or high or low saturated rubber, and component B, containing DCPD, a tungsten-based catalyst, a compound that increases the solubility of the catalyst — alcohol or phenol, a Lewis base or a chelating agent — nitriles, ethers or acetates, and juice - or low saturated rubber, in which component B is obtained by adding to the catalyst solution a compound that increases the solubility of the catalyst, followed by blowing hydrogen chloride, introducing a Lewis base or chelating agent into the solution and adding the resulting catalyst solution to a solution of high or low saturated rubber in DCPD, characterized in that in the preparation of component A, the activator is pre-dissolved in hexane or nephras, and before it is introduced into the rubber solution in DCPD in the last first initially administered moderator in such an amount that the molar ratio of moderator / activator was (1-10): 1.