RU2361892C2 - Method of producing light thermoplastic rubber - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: thermoplastic rubber is obtained through pre-mixture of light 28-60 wt fractions with 3-30 wt fractions of fine-grained silicon dioxide, 10-50% oil of its total amount, making up 35-70 wt fractions, 0.5-4.0 wt fractions organic silicon compound, chosen from vinyltriethoxysilane, methacryltriethoxysilane or methacryloxypropyltriethoxysilane, 0.2-2 wt fractions zinc strearate. The obtained product is then mixed with 40-72 wt fractions crystalline olefin, remaining amount of oil, 3.5-10 wt fractions alkyl phenol-formaldehyde resin, 2-3 wt fractions zinc oxide and 2.6-3.9 wt fractions tin dichloride.

EFFECT: method allows for obtaining light thermoplastic rubber with lower hardness and higher melt fluidity.

5 ex, 4 tbl

Description

The invention relates to a method for producing thermoplastic rubbers (TPR), which can be used for the manufacture of various elastic rubber products, such as hoses, seals, gaskets, elastic products of car interiors, corrugated products, by extrusion, injection molding and blow molding.

A known method of producing thermoplastic rubber by pre-mixing the elastomer with a filler - carbon black and sulfur-type vulcanizing agents under conditions that allow the vulcanization of the elastomer, followed by the addition of crystalline polyolefin (Pat. GDR No. 271909 A1, MKI 5 C08F 3/20, publ. 20.09. 89).

This method does not allow to obtain thermoplastic rubber with low hardness and high melt flow at high strength values. So, with shore hardness A equal to 89 srvc. units, tensile strength of thermoplastic rubber is 13.4 MPa, elongation at break is 260%, melt flow rate is 0.2 g / 10 min. In addition, the thermoplastic rubber obtained by this method has a black color.

A known method of producing TPR by pre-mixing crystalline polyolefin, polyolefin elastomer, light filler, oil and curing agents of the phenolic type under conditions that provide partial or complete crosslinking of the polyolefin elastomer with subsequent mixing of the resulting composition with a copolymer of ethylene with vinyl acetate or ethylene with alkyl acrylate (US Pat. No. 5051478, MKI ⁵ C08L 9/00, publ. 24.09.1991).

This method does not allow to obtain thermoplastic rubber with low hardness and high fluidity of the melt at high strength characteristics. So, with a shore hardness A equal to 64 srvc. units, tensile strength of thermoplastic rubber is 4.6 MPa, elongation at break of 220%, melt flow rate of 1.2 g / 10 min.

The closest in technical essence and the achieved effect is a method of producing TPR by co-mixing the crystalline polyolefin with a polyolefin elastomer, a light filler, oil and curing agents of the phenolic type under conditions that allow the vulcanization of the elastomeric component (US Pat. No. 6255389, MKI ⁷ C08L 27/00 published on 07/03/2001.).

The disadvantage of this method is the high hardness and low fluidity of the melt at high strength values. So, with a hardness of thermoplastic rubber 77 srvc. units its strength is 8.9 MPa and a melt flow rate of 0.8 g / 10 min.

The objective of the invention is to obtain on the basis of a mixture of crystalline polyolefin and polyolefin elastomer light TPR with low hardness and high melt flow rate while maintaining high strength characteristics.

The technical problem is solved in that in the method for producing light thermoplastic rubber by co-mixing crystalline polyolefin, polyolefin elastomer obtained by copolymerization of olefins and diene, light filler, oil and curing agents of the phenolic type under conditions that cure the polyolefin elastomer, they are mixed beforehand 30-120 ° C polyolefin elastomer, which is an ethylene-propylene-diene copolymer or butyl rubber, with a filler, etc. which is a highly dispersed silicon oxide and 10-50% of the total oil in thermoplastic rubber, with an additionally introduced silicon-borne compound selected from vinyltriethoxysilane, methacryltriethoxysilane or methacryloxypropyltriethoxysilane, and zinc stearate, followed by mixing with an oil and crystalline polyol consisting of a mixture of alkyl phenol formaldehyde resin, zinc oxide and tin dichloride, in the following ratio of components, ma . parts:

crystalline polyolefin 28-60 - ethylene-propylene-diene copolymer or butyl rubber 40-72 fine silica 3-30 - vinyltriethoxysilane or methacryltriethoxysilane or methacryloxypropyltriethoxysilane 0.5-4.0 - oil 35-70 - zinc stearate 0.2-2 - alkyl phenol formaldehyde resin 3,5-10 - zinc oxide 2-3 - tin dichloride 2.6-3.9

that allows you to get a light TPR, combining low hardness and high fluidity of the melt while maintaining high strength properties. This allows you to get a TPR with a ratio of strength / hardness (MPa / srvc. Units) of at least 1.08 and up to 1.58.

The substances used in the method

As the crystalline polyolefin, low pressure polyethylene (HDPE) GOST 16838-85, crystallizable copolymers of ethylene with α-olefins containing 0.1-10 wt.% Α-olefin with the number of carbons in the α-olefin from 3 to 6 are used (Ethylene copolymers / E.V. Veselovskaya et al. L .: Chemistry, 1983), polypropylene (PP) and a random copolymer of propylene with 3-8% ethylene GOST 26996-86.

GOST 18307-78 white carbon black, BS GOST 14922-77 aerosil and other types of highly dispersed silicon oxide (Fillers for polymer composite materials / Edited by G.S. Kats and D.V. Milevsk can be used as highly dispersed silicon oxide). M.: Chemistry 1981. - 736 p.)

As the elastomer obtained by copolymerization of olefins and dienes, ethylene-propylene-diene copolymers can be used, for example a copolymer of ethylene with propylene with dicyclopentadiene, a copolymer of ethylene with propylene and ethyldennorbornene, for example, SKEPT brand (TU 2294-022-0576680101) ; a copolymer of isobutylene with isoprene or butadiene, for example butyl rubber (Handbook of rubber worker. Materials of rubber production / P.I. Zakharchenko et al. M: Chemistry, 1971. - 606 p.).

Any alkylphenol-formaldehyde resins with vulcanization activators, for example, n-tert-butylphenol-formaldehyde resin, n-tert-octylphenol-formaldehyde resin, are used as vulcanizing agents (Handbook of rubber producer. Materials of rubber production / P.I. Zakharchenko et al. M .: Chemistry, 1971. - 606 p .; G.A. Bloch Organic rubber vulcanization accelerators L .: Chemistry, 1972.). As vulcanization activators, a mixture of zinc oxide with tin chloride is used (Schwartz A.G., Dinzburg B.N. Combination of rubbers with plastics and synthetic resins. M: Chemistry, 1972, p. 158).

As the oil, paraffin, naphthenic or aromatic hydrocarbon oil of mineral or synthetic origin can be used, used as a softener or plasticizer in rubbers, for example PM (TU 38.401172-90), MP-75 (TU 38.101952-83), Stabiloil-18 (TU 38 101367-78) and others (Handbook of the rubber worker. Materials of rubber production / P.I. Zakharchenko and others. M .: Chemistry, 1971. - 606 s).

As the organosilicon compound, vinyltriethoxysilane (VTES), methacryltriethoxysilane (MTES), methacryloxypropyltriethoxysilane (MAPTES) can be used (E. Plueddemann, Silane Coupling Agents, 2nd ed, Plenum Press, New York, 1991 .; W. Noll, Chemistry and Technology Silicones, Academic Press, New York, 1968.)

The invention is illustrated by the following examples of specific performance.

Example 1. In the mixer "Brabender" at 100 ° C are mixing in the first stage, 67 wt. parts of a copolymer of ethylene, propylene and ethylidene norbornene (synthetic rubber ethylene propylene triple - SKEPT), 25 wt.h. silicon oxide in the form of white carbon black brand BS-100 and with 3 wt. including vinyltriethoxysilane, 30 parts by weight oil and 0.2 wt.h. zinc stearate for 7 min. Then the mixture is discharged from the mixer. In the second stage, "Brabender" at 190 ° C mix 125.2 wt.h. obtained in the first stage of the mixture with 33 wt.h. polypropylene, 40 parts by weight oils, 3.9 parts by weight tin chloride and 4.1 wt.h. phenol formaldehyde resin. After loading all components, mixing is carried out for 3 minutes Then the mixture is unloaded and subjected to tests. Material properties are given in table 4.

Methods of testing samples. Relative tensile strength, elongation at break, relative residual elongation were determined according to GOST 270-75 on samples obtained by extrusion. Shore A hardness was determined according to GOST 263-75, melt flow rate (MFR) was determined according to GOST 11645-73 at a load of 10 kg and a temperature of 190 ° C.

Examples 2-6 are performed according to the same technology as example 1. The samples in examples 2-5 differ only in composition. The compositions and properties of the samples in examples 2-5 are shown in tables 1 and 4.

Example 1P (prototype). In the Brabender mixer at 190 ° C, 67 wt. parts of a copolymer of ethylene, propylene and ethylidene norbornene (synthetic rubber ethylene propylene triple - SKEPT) with 33 wt.h. polypropylene, 70 parts by weight oil, 25 parts by weight silicon oxide in the form of white carbon black brand BS-100, 3.9 wt.h. tin chloride and 4.1 wt.h. phenol formaldehyde resin. After loading all components, mixing is carried out for 10 minutes Then the mixture is unloaded and subjected to tests. Material properties are given in tables 2 and 4.

Examples 2P-5P are performed according to the same technology as Example 1K, only the composition of the TPR is different. The compositions and properties of the samples according to examples 2P-5P are shown in tables 2 and 4.

Example 1K (control). In the Brabender mixer at 190 ° C, 67 wt. parts of a copolymer of ethylene, propylene and ethylidene norbornene (synthetic rubber ethylene propylene triple - SKEPT) with 33 wt.h. polypropylene, 70 parts by weight oil, 25 parts by weight silicon oxide in the form of white carbon black brand BS-100, 3 wt.h. vinyltriethoxysilane and 0.2 wt.h. zinc stearate, 3.9 parts by weight tin chloride and 4.1 wt.h. phenol formaldehyde resin. After loading all components, mixing is carried out for 10 minutes Then the mixture is unloaded and subjected to tests. Material properties are given in table 4.

Example 5K is performed by the same method and the same technology as example 1K. Only the composition is different, which is shown in table 3. The properties of the TPR are shown in table 4.

Table 1 The composition of light thermoplastic rubber obtained by the proposed method No. p / p The composition at the first stage of mixing, parts by weight (parts by weight) The composition of the components added in the second stage of mixing to the mixture of the first stage wt.h. Elastomer Wok Oil Zinc stearate CBS AFFS Oil Polyolefin SnCl ₂
2H ₂ O Zno Mark parts by weight Mark wt.h Mark parts by weight Mark parts by weight one SKEPT 67 BS-100 25 thirty 0.2 VTES 3.0 4.1 40 PP 33 3.9 3 2 SKEPT 70 A-175 twenty twenty 0.5 VTES 1,2 3,5 fifty PP thirty 3.5 2 3 SKEPT 63 A-175 twenty twenty 1,0 MTES 1,0 6 40 PP 37 3.6 2 four BC 60 A-300 eighteen twenty 1,5 MAPTES 0.5 8 thirty HDPE 40 3,1 3 5 BC 55 BS-100 fifteen fifteen 0.9 MAPTES 0.5 10 thirty HDPE 45 2.6 3 6 SKEPT 72 A-175 3 10 1,0 MAPTES 0.8 four 25 PP 28 2.6 2.5 table 2 The composition of light thermoplastic rubbers obtained by a known method No. p / p The composition at the first stage of mixing, parts by weight (parts by weight) Elastomer Wok Oil AFFS Polyolefin SnCl ₂ Zno Mark parts by weight Mark wt.h Mark parts by weight 2H ₂ O 1P SKEPT 67 BS-100 25 70 4.1 PP 33 3.9 3 2P SKEPT 70 A-175 twenty 70 3,5 PP thirty 3,5 2 3P SKEPT 63 A-175 twenty 60 6 PP 37 3.6 2 4P BC 60 A-300 eighteen fifty 8 HDPE 40 3,1 3 5P BC 55 BS-100 fifteen 45 10 HDPE 45 2.6 3 VOK - highly dispersed silicon oxide, KOS - organosilicon compound, PP - polypropylene, HDPE - low pressure polyethylene, SKEPT - synthetic rubber, ethylene propylene triple, BK - butyl rubber, AFPS - alkyl phenol formaldehyde resin, VTES - vinyltriethoxyethylpropylene, methylene ethoxytriethyl ethoxypropylene, methylene ethylene ethylene ethylene tetraethyl ethanethyl ethrytisethylpropylene, BS-100, A-175, A-300 - brands of silicon oxide.

Table 3 The composition of light thermoplastic rubbers obtained by a known method No. p / p Composition, wt. parts (parts by weight) Elastomer Wok Oil Zinc stearate CBS AFFS Polyolefin SnCl ₂ 2H ₂ O Zno Mark parts by weight Mark parts by weight Mark parts by weight Mark parts by weight 1 TO SKEPT 67 BS-100 25 70 0.2 VTES 3.0 4.1 PP 33 3.9 3 5K BC 55 BS-100 fifteen 45 0.9 MAPTES 0.5 10 HDPE 45 2.6 3 Table 4 Properties of light thermoplastic rubbers No. p / p The properties N, conv. σ _y , MPa N / σ _y , conventional units / MPa ε,% ε _oct ,% PTR, g / 10 min one 59 5,4 0.108 370 eleven 5.9 2 51 5.3 0.104 310 17 6.6 3 65 7.8 0.12 410 twenty 3.8 four 72 9.9 0.137 440 24 3.9 5 82 13.0 0.158 490 thirty 5.8 6 70 9.6 0.137 370 23 3.8 1P 61 4.3 0,070 310 eleven 2,8 2P 55 4.1 0,075 285 16 3.3 3P 66 5.9 0,089 310 twenty 2.2 4P 74 7.2 0,097 230 22 2.1 5P 82 8.1 0,099 210 29th 2,4 1 TO 61 4.2 0,069 280 10 3.3 5K 85 8.0 0,094 330 thirty 3,1 H - shore hardness A, σ _y - conditional tensile strength, ε - elongation at break, ε _ost - relative residual elongation, PTR - melt flow index

It should be noted that it is preferable to carry out the stage of preliminary mixing of the elastomer with filler, organosilicon compound, zinc stearate and oil in a batch system, such as rollers, a two-rotor mixer of the closed type, etc., and the stage of subsequent displacement of the obtained intermediate with the crystalline complex, the remaining amount oils and curing agents are believed to be carried out in a continuous mixer, such as a twin screw extruder.

A comparison of samples 1 and 1P, 2 and 2P, 3 and 3P, 4 and 4P, 5 and 5P of table 1 shows that the proposed method allows to obtain a less solid and more durable TPR than the known method. So, samples 1 and 1P have a similar composition, but differ in the method of preparation. As a result, sample 1 obtained by the proposed method has lower hardness and higher values of strength, PTR, elongation and hardness / strength ratio than sample 1K obtained by the known method. The same applies to samples 2 and 2P, 3 and 3P, 4 and 4P, 5 and 5P. All TPR samples obtained by the proposed method (1-5) have a higher hardness / strength ratio (N / σ _y ) and higher melt flow rate than TPR samples obtained by the known method (1P-5P).

To prove that not additional components (organosilicon compound and zinc stearate) led to improved properties of the compositions, control experiments 1K and 5K were made, the composition of which is completely identical to samples 1 and 5, but they were obtained by a known method (by joint mixing of all components). It can be seen (table 4) that the control samples have higher hardness and lower values of strength and melt flow rate than samples of the same composition, but obtained by the proposed method.

It is important that the proposed method can be obtained soft TPD with high mechanical properties and having a light color. The light color of the TPR makes it easy to dye it in any color, both at the stage of its preparation and at the stage of processing into products by simply adding pigment or pigment concentrate. For TPR containing a dark filler, such as, for example, carbon black, or vulcanizable with sulfur accelerators that give a dark color TPR, this is impossible. The ability to paint significantly expands the scope of the material, improves the appearance of the product.

Thus, the proposed method allows to obtain light thermoplastic rubber with lower hardness and higher melt flow than the known method, while maintaining high strength properties.

Claims (1)

A method of obtaining a light thermoplastic rubber by co-mixing a crystalline polyolefin, polyolefin elastomer obtained by copolymerization of olefins and dienes, a light filler, oil and phenolic type vulcanizing agents under conditions that cure the polyolefin elastomer, characterized in that the mixture is preliminarily mixed at a temperature of 30-120 ° C polyolefin elastomer, which is an ethylene-propylene diene copolymer or butyl rubber, with a filler representing finely dispersed silicon oxide and 10-50% of the total oil in thermoplastic rubber, with an additionally introduced silicon-bound compound selected from vinyltriethoxysilane, methacryltriethoxysilane or methacryloxypropyltriethoxysilane, and zinc stearate, followed by mixing with crystalline polyolefin oil and residual mineral olefin, consisting of a mixture of alkyl phenol-formaldehyde resin, zinc oxide and tin dichloride, in the following ratio, wt.h. :
crystalline polyolefin 28-60 polyolefin elastomer 40-72 fine silica 3-30 vinyltriethoxysilane, or methacryltriethoxysilane, or methacryloxypropyltriethoxysilane 0.5-4.0 oil 35-70 zinc stearate 0.2-2 alkyl phenol formaldehyde resin 3,5-10 zinc oxide 2-3 tin dichloride 2.6-3.9