RU2619947C2 - Method of producing oil resistant thermoplastic rubber - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing thermoplastic rubber (TPR) with high resistance to hydrocarbon oils, which can be used for making various elastic industrial rubber articles operating under conditions of contact with oil products. In method of producing oil resistant thermoplastic rubber mixing process is carried out in two steps. First step includes mixing polypropylene, butadiene-nitrile rubber and a modifier in form of organic peroxide and oligoester acrylate, containing at least two vinyl groups, or triazine derivative, containing at least two allyl groups. Second step includes mixing product of first step, olefin rubber, mineral oil, curing agent for rubber, which is an alkyl phenol formaldehyde resin and vulcanisation activator in form of tin dichloride or aluminium chloride.

EFFECT: invention enables to obtain thermoplastic rubber, having high melt flow index with low oil absorption.

1 cl, 3 tbl, 11 ex

Description

The invention relates to a method for producing thermoplastic rubber (TPR) with high resistance to hydrocarbon oils, which can be used for the manufacture of various elastic rubber products by extrusion, injection molding and blow molding, such as: hoses, seals, gaskets, elastic automobile products, corrugated elastic products, and other elastic products working in contact with petroleum products.

A known method of producing thermoplastic rubber by joint mixing of polypropylene (PP), synthetic rubber (SC), filler, mineral oil, organic peroxide, antioxidants (Pat. 2269549, RF, IPC C08L 9/02).

This TPR has a very low resistance to oils, swelling in oil of grade SZHR-3 at 100 ° C is 60-120%.

A known method for producing oil-resistant thermoplastic rubber by co-mixing polypropylene, nitrile butadiene rubber (BNK), olefin rubber, a vulcanizing agent and a modifier, which is a grafted copolymer of polypropylene and nitrile butadiene rubber with amino terminal groups (US Pat. No. 4,040,865 US 9/02).

This TPR has a low melt flow rate (MFR) (0.02-0.2 g / 10 min at a temperature of 230 ° C and a load of 2.16 kg) and high oil absorption (21-48%).

The closest in essence and technical level is the method of obtaining oil-resistant thermoplastic rubber by co-mixing polypropylene, nitrile butadiene rubber, olefin rubber, mineral oil, a vulcanizing agent of alkyl phenol formaldehyde resin and a vulcanization activator - tin chloride or aluminum chloride and a modifier of ) containing at least two isocyanate groups, polypropylene with a content of 1-6% grafted maleic anhydride (MA) or maleic isloty and plasticizer solubility parameter at least 18 (kJ / m ^{3) 1/2} (US Pat. 2,366,671 RF IPC C08L 9/02).

This TPR has a low PTR (0.2-0.6 g / 10 min at a temperature of 230 ° C and a load of 2.16 kg).

The objective of the invention is to obtain a thermoplastic rubber based on polypropylene and nitrile rubber, combining an increased melt flow rate with low oil absorption (increased oil resistance).

The technical problem is solved in that the method of producing oil-resistant thermoplastic rubber by mixing polypropylene, nitrile butadiene rubber, olefin rubber, mineral oil, a modifier, a vulcanizing agent for rubbers - alkyl phenol formaldehyde resin and a vulcanization activator - tin chloride or aluminum chloride, differs in that as a modifier, organic peroxide and oligoester acrylate containing at least two vinyl groups, or a triazine derivative containing at least two ally groups, in addition, the mixing is carried out in two stages, in the first stage polypropylene, nitrile butadiene rubber and a modifier are mixed, in the second stage the product of the first stage, olefin rubber, mineral oil, vulcanization activator, vulcanizing agent for rubbers are mixed, in the following ratio components (%):

polypropylene 20-30 nitrile butadiene rubber 30-63 olefin rubber 5-25 organic peroxide 0.2-0.7 oligoester acrylate containing at least two vinyl groups, or a derivative triazine containing at least two allyl groups 0.8-2 mineral oil 2.5-26 specified curing agent 0.7-3.5 vulcanization activator 0.1-0.35

which allows to obtain a TPR with low oil absorption (not more than 22%) and high PTR (not less than 1.6 g / 10 min) with a load of 2.16 kg.

Table 1 shows the compositions and table 3 characteristics of the proposed TPR.

USED SUBSTANCES

As polypropylene, polypropylene or a copolymer of propylene and ethylene with an ethylene content of 2-8%, for example, polypropylene according to TU 2211-3136-05766801-2006 (Plastics. Properties and applications. Reference // Katsnelson M.Yu., Gurgen A .B.L .: Chemistry, 1978, 382 p.).

As the nitrile butadiene rubber, a random copolymer of butadiene and acrylic acid nitrile with a content of bound acrylic acid nitrile from 18 to 42 masses can be used. % and others. (A large directory of the rubber engineer, edited by S.V. Reznichenko and others. M .: Tekhinform, 2012. - 744 p.). Industrial examples of such rubbers are the brands BNKS-18 AMN, BNKS-28 AMN, BNKS-40 AMN, manufactured by OJSC Krasnoyarsk Synthetic Rubber Plant.

As the olefin rubber obtained by the copolymerization of olefins and diene, the following can be used: a copolymer of ethylene with propylene and dicyclopentadiene, a copolymer of ethylene with propylene and ethylidene norbornene (The Great Resincer's Guide / S.V. Reznichenko et al. M .: Techinform, 2012. - 744 pp.), For example, the SKEPT brand (TU 2294-022-05766801-2002), Vistalon manufactured by ExxonMobil, Keltan manufactured by Lanxess.

As organic peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexin-3 can be used; di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert-butyl peroxy) hexane; tert-butyl cumyl peroxide, di (tert-butyl peroxyisopropyl) benzene; 3,3,5,7,7-pentamethyl-1,2,4-trioxepane; dicumyl peroxide et al. (Zweichel X. et al. Additives to polymers. Handbook. St. Petersburg: Profession, 2010, p. 702-707). Examples of industrial brands of these peroxides are Trigonox 145, Trigonox B, Trigonox 101, Trigonox Τ, Perkadox 14, Trigonox 311, Perkadox BC and others manufactured by Akzo Nobel.

As oligoether acrylate containing at least two vinyl groups, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, triethylene glycol dimethacrylate (TGM-3 according to TU 6-02-109-91), etc. can be used.

As a triazine derivative containing at least two allyl groups, triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimetal isocyanurate, etc. can be used. Examples of industrially produced brands of such substances are TAC, TAIC, TAICROS manufactured by Evonik.

As mineral oil can be used paraffin, naphthenic or aromatic hydrocarbon oil of mineral origin, used as a softener or plasticizer in rubbers. For example, mineral oils of the PM (TU 38.401172-90), Stabiloil-18 (TU 38.101367-78), Primol 352 brands manufactured by ExxonMobil and others can be used (A large guide to the rubber machine edited by S.V. Reznichenko and others. M .: Techinform, 2012 .-- 744 p.).

As the vulcanizing agents are any alkyl phenol-formaldehyde resins (AFPS) with vulcanization activators. For example, n-tert-butylphenol-formaldehyde resin, n-tert-octylphenol-formaldehyde resin (Big Handbook of Rubber Carrier / CB Reznichenko et al. M .: Tekhinform, 2012. - 744 p .; G.A. Bloch. Organic rubber vulcanization accelerators. L. : Chemistry, 1972). As activators of vulcanization, tin chloride or aluminum chloride is used (Schwartz A.G., Dinzburg B.N. Combining rubbers with plastics and synthetic resins. M: Chemistry, 1972. - 158 p.).

In addition, the composition may include well-known additives commonly used for such polymeric materials, such as fillers, antioxidants, lubricants that improve processability in products, anti-azonates (Zweichel X. Additives to polymers. Handbook. St. Petersburg: Profession, 2010, - 1144 s.).

The present invention illustrates the following examples of specific performance. The composition and properties of thermoplastic rubber compounds are given in tables 1-3.

Example 1. TPR is obtained in two stages. At the first stage, in a Brabender mixer at a temperature of 180 ° C for 3 minutes they mix 26% of Balen 01030 polypropylene, 63% of BNKS-40 AMN butadiene-nitrile rubber, then add 2% TGM-3, 0, oligoester acrylate 5% organic peroxide brand Trigonox 101 and mix for 5 minutes, then add antioxidants and mix for another 1 minute, the resulting mixture is discharged from the mixer. In the second stage, at 180 ° C, the mixture obtained in the first stage is mixed with the following components: 91.7% of the product of the first stage, 5% of Keltan 5508 ethylene-propylene rubber, 2.5% of Primol 352 oil, mixing is carried out for 2 minutes, then add 0.1% tin dichloride dichloride, 0.7% butylphenol formaldehyde resin and continue mixing for 5 minutes to carry out the rubber vulcanization process. It turns out thermoplastic rubber (TPR), which is subjected to tests. The properties of the TPR are shown in table 3.

Example 2-6 Perform in the same order and under the same modes as example 1. Examples differ only in composition. The properties of the obtained TPR are shown in table 3.

Example 1K (control). TPR is obtained by the joint mixing of all components. In a Brabender mixer at a temperature of 180 ° C for 3 min, 26% of Balen 01030 brand polypropylene, 63% of nitrile butadiene rubber of BNKS-40 AMN grade, 5% of Keltan 5508 olefin rubber, 2.5% of oil are mixed grade Primol 352. Then, 2% TGM-3 grade oligoester acrylate, 0.1% tin dichloride, 0.7% Trigonox 101 organic peroxide, 0.7% butylphenol-formaldehyde resin are added to the mixer and mixed for 5 minutes to carry out the vulcanization process of the elastomer, then antioxidants are introduced and mixing is carried out for another 1 minute. It turns out thermoplastic rubber, which is subjected to tests. Material properties are given in table 3.

Example 2K (control). It is performed in the same order and under the same modes as Example 1K; it differs only in composition.

Example 1P (prototype). In a Brabender mixer at a temperature of 180 ° C for 7 minutes they mix 21% of Balen 01030 brand PP, 35.5% of BNKS-40 nitrile butadiene rubber, 7% of PP containing 1.2% grafted maleic anhydride , Polybond 3200 grade, 3.5% SKEPT grade olefin rubber, 0.85% toluene diisocyanate, 24.5% PM mineral oil and 4.94% tricresyl phosphate plasticizer. Then, 2.48% butylphenol-formaldehyde resin and 0.23% tin dichloride dichloride are added to the mixer and mixing is continued for 4 minutes to effect the curing process of the elastomer. It turns out thermoplastic rubber (TPR), which is subjected to tests.

Examples 2P and 3P (prototype). Perform in the same order and under the same modes as example 1P. Examples differ only in composition. The properties of the obtained TPR are shown in table 3.

Methods of testing samples.

The melt flow rate (MFR) was determined according to GOST 11645-73 with a load of 2.16 kg and a temperature of 230 ° C. The deformation-strength properties of materials (conditional tensile strength σ _p , elongation at break ε _p ) were determined according to GOST 270-75. Oil resistance (oil absorption - α) was determined according to GOST 9.030-74 by swelling at 100 ° C for 72 hours in oil SZHR-3. Shore A hardness was determined according to GOST 263-75 over a period of 5 s.

From the above examples it is seen that the proposed method allows to obtain materials having a higher melt flow rate (MFR = 1.6-2.8 g / 10 min, examples 1-6) than the thermoplastic rubber obtained by the prototype (MFR = 0 , 2-0.6 g / 10 min, examples 1P-3P). Such an increase in MFI in materials according to the proposed method expands the possibilities for processing thermoplastic rubber into products.

Materials with low MFIs, such as those of materials of the prototype (less than 0.7 g / 10 min at 230 ° C and 2.16 kg), cannot be processed into products by injection molding (EL Kalinichev. Properties and processing of thermoplastics : Reference manual. - L.: Chemistry, 1983 - 288 p.). The proposed method allows to obtain thermoplastic rubber with a high MFI equal to 1.6-2.8 g / 10 min, which allows them to be easily processed into high-quality products by a high-performance and accurate injection molding method. (1. Kalinichev E.L. Properties and processing of thermoplastics: A reference guide. - L .: Chemistry, 1983. - 288 pp. 2. Bortnikov V.G. Fundamentals of technology for processing plastics. M: Chemistry, 1983, 304 s. .).

The proposed method allows to obtain thermoplastic rubber with higher oil resistance than that of the materials of the prototype.

For thermoplastic rubbers, hardness is an important indicator. The field of application of TPR depends on hardness. A change in hardness always entails a change in other properties (Holden D. Thermoelastoplasts. - St. Petersburg: Profession, 2011 - 720 p.), Including oil resistance. Therefore, to compare any indicators of thermoplastic rubbers is possible only with comparable values of hardness. As can be seen from tables 2 and 3, with equal hardness, the proposed method allows to obtain a material having less oil absorption than the material obtained by the prototype.

In addition, the TPR obtained by the proposed method (Tables 1 and 3) is not inferior in deformation and strength characteristics - strength (σ _p ) and elongation (ε _p ), thermoplastic rubber obtained by the prototype (tables 2, 3 )

To prove that not only a change in the component composition (introduction of peroxide and oligoether acrylate or a triazine derivative) leads to an improvement in the properties of the compositions, control experiments 1K and 2K were made, the composition of which is completely identical to samples 1 and 2, but they were obtained by a known method ( joint mixing of all components). It is seen (tab. 1, 3) that the control samples have lower strength, elongation, PTR and greater oil absorption than samples obtained by the proposed two-stage method.

Thus, the proposed method allows to obtain thermoplastic rubber with a higher melt flow rate than the known method, while maintaining high deformation-strength properties and oil resistance.

Claims (2)

The method of obtaining oil-resistant thermoplastic rubber by mixing polypropylene, nitrile butadiene rubber, olefin rubber, mineral oil, modifier, vulcanizing agent for rubbers - alkylphenol-formaldehyde resin and vulcanization activator - tin chloride or aluminum chloride, characterized in that it contains organic peroxide and modifier oligoester acrylate containing at least two vinyl groups, or a triazine derivative containing at least two allyl groups, in addition, mixing in FLS in two stages, the first stage is mixed polypropylene, butadiene-nitrile rubber and modifier in the second step is mixed product of the first step, an olefin rubber, a mineral oil, a vulcanizing agent and an activator for rubber vulcanization, with the following component ratio (%): polypropylene 20-30 nitrile butadiene rubber 30-63 olefin rubber 5-25 organic peroxide 0.2-0.7 oligoester acrylate containing at least two vinyl groups, or a derivative triazine containing at least two allyl groups 0.8-2 mineral oil 2.5-26 specified curing agent 0.7-3.5 vulcanization activator 0.1-0.35