CN102040841B - Dynamic vulcanization halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer - Google Patents

Abstract

The invention relates to the technical field of thermoplastic elastomer materials, in particular to a dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer and a preparation method thereof. The invention comprises, by weight percentage, 100 parts of silicone rubber, 50-100 parts of polyolefin, 10-50 parts of white carbon black, 100-200 parts of halogen-free flame retardant, 1-5 parts of compatibilizer, 1-2 parts of antioxidant, 1-3 parts of cross-linking agent, 1-5 parts of hydroxy silicone oil and 0.5-1 part of silane coupling agent. The invention can be widely used in many fields such as automobiles, electronic and electrical equipment, cables and wires, medical equipment, architectural decoration, etc., is not only halogen-free and environmentally friendly, but also has good flame retardant effect, and its oxygen index can reach up to 38.

Description

A dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer

technical field

The invention relates to the technical field of thermoplastic elastomer materials, in particular to a dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer and a preparation method thereof.

Background technique

Dynamically vulcanized thermoplastic elastomers are materials that combine the elasticity of rubber with the melt flow and reusability of thermoplastics. Its notable feature is that rubber and thermoplastic resin are vulcanized "in situ" during melt blending; at the same time, the blend is subjected to high-speed shear stress of the mixing machine, and the rubber is vulcanized and cross-linked particles, also known as microdomains. (Domain), dispersed in the resin, this crosslinked rubber micro-domain mainly provides the elasticity of the blend, and the resin provides plastic flow at the melting temperature. Due to its excellent physical and mechanical properties, electrical insulation properties and processing performance, it is widely used in many fields such as automobiles, electronics and electrical appliances, wires and cables, medical equipment, construction packaging, etc., gradually replacing vulcanized rubber and soft plastics.

Silicone rubber (MVQ), as a polymer material with both inorganic and organic properties, has excellent high temperature resistance, weather resistance, aging resistance, low compression set and electrical insulation properties compared with general organic rubber. Thermoplastic elastomers prepared with silicone rubber as the main component have more excellent properties than ordinary thermoplastic elastomers. In the prior art, the formulations and preparation methods of EPDM/PP and NBR/PP dynamic vulcanized thermoplastic elastomers are mainly concentrated, and there are few research reports on thermoplastic elastomers with silicone rubber as the elastic component. Chinese patent CN 1188468C discloses a thermoplastic silicone elastomer prepared by compatibilizing polyamide resin, which is formed by dynamic curing of polyamide resin, silicone base material, compatibilizer and specific crosslinking agent; U.S. Patent US6013 715 (Gornowiez et al.) disclose the preparation of TPSiV elastomers, which are dispersed in polyolefin or polybutylene terephthalate resins as silicone rubber gums (or filled silicone rubbers) and then made by hydrosilylation curing systems. The compound is dynamically vulcanized therein. Although the above-mentioned patents disclose some formulation technologies of thermoplastic silicone elastomers, their flame retardancy is relatively low, and the oxygen index is generally less than 22.

With the consideration of safe use, people began to study the flame retardant properties of thermoplastic silicone elastomers. The Chinese patent application number 200310106228.0 discloses a dynamically vulcanized flame retardant EPDM/PP thermoplastic Elastomer, which is mainly composed of EPDM, polypropylene (PP), cross-linking system, flame retardant system, filler, plasticizer and additives, and is dynamically vulcanized by a twin-screw extruder It is prepared by extrusion granulation. Although the oxygen index (OI) of this thermoplastic elastomer can reach up to 32, its flame retardant system uses bromide, which is not environmentally friendly. The Chinese patent application number is 00310112701.6, which also discloses a halogen-free flame-retardant dynamic vulcanized EPDM rubber/polypropylene thermoplastic elastomer, which is mainly composed of EPDM rubber (EPDM), polypropylene (PP), cross-linked It is composed of a combination agent, a halogen-free flame retardant system, a plasticizer and an auxiliary agent, and is produced through dynamic vulcanization and extrusion granulation of an extruder. Although a halogen-free flame retardant system is used, its oxygen index is up to 30, and its resistance The combustion effect is relatively low, and it cannot be 100% safe.

Contents of the invention

In order to solve the above problems, one of the objectives of the present invention is to provide a dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer.

Another object of the present invention is to provide a method for preparing the above-mentioned dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer; this invention not only has a simple preparation process, but also has low cost.

The present invention is achieved through the following technical solutions:

A dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer, the raw material of which comprises the following components calculated in parts by weight:

Methyl vinyl silicone rubber raw rubber 100 parts;

Polyolefin resin 50-100 parts;

White carbon black 10-50 parts;

Halogen-free flame retardant system 100-200 parts;

Compatibilizer 1-5 parts;

Antioxidant 1-2 parts;

1-3 parts of cross-linking agent;

Silane coupling agent 0.5-1 part;

Hydroxy silicone oil 1 to 5 parts;

Wherein, the methyl vinyl silicone rubber raw rubber has a vinyl mole fraction of 0.05%-0.5%.

The polyolefin resin is one or a mixture of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) or polypropylene (PP).

The white carbon black is fumed white carbon black or precipitated white carbon black.

The crosslinking agent is di-tert-butyl peroxide (DTBP), dicumyl peroxide (DCP) or 2,5-dimethyl-2,5-di-tert-butylperoxyhexane (DBPMH) one or more combinations.

The silane coupling agent is methyltriethoxysilane, vinyltriethoxysilane, gamma-(methacryloxy)propyltrimethoxysilane, gamma-(2,3-epoxypropoxy ) One or more combinations of propyltrimethoxysilane.

The compatibilizer is silane-grafted polyolefin resin, such as: silane-grafted LDPE, silane-grafted LLDPE, or silane-grafted HDPE.

Preferably, the halogen-free flame retardant system is a compound of aluminum hydroxide and zinc borate, melamine cyanurate or microencapsulated red phosphorus, and the weight ratio of the components of the system is:

Aluminum hydroxide 100 parts;

Zinc borate, melamine cyanurate or microencapsulated red phosphorus 0-20 parts.

The halogen-free flame retardant system is a compound of magnesium hydroxide and zinc borate, melamine cyanurate or microencapsulated red phosphorus, and the weight ratio of the components of the system is:

Magnesium Hydroxide 100 parts;

Zinc borate, melamine cyanurate or microencapsulated red phosphorus 0-20 parts.

The halogen-free flame retardant system is a compound of aluminum hydroxide, magnesium hydroxide and zinc borate, melamine cyanurate or microencapsulated red phosphorus, and the weight ratio of the components of the system is:

Aluminum hydroxide and magnesium hydroxide 100 parts;

Zinc borate, melamine cyanurate or microencapsulated red phosphorus 0-20 parts;

The weight ratio between the aluminum hydroxide and magnesium hydroxide is 1:0.2-1.

Preferably, the antioxidant is tetrakis[methyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester or β-(3,5-di-tert-butyl n-octadecyl-4-hydroxyphenyl)propionate.

The antioxidant is tetrakis [methyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester or β-(3,5-di-tert-butyl-4- Hydroxyphenyl) propionic acid n-octadecyl alcohol ester and tris [2,4-di-tert-butylphenyl] phosphite in a weight ratio of 1 to 2:1.

The preparation method of dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer comprises the following preparation steps:

A. Mix silicone rubber raw rubber, white carbon black, flame retardant, hydroxy silicone oil, and silane coupling agent in a kneader at 150±5°C to obtain the mixed rubber I;

B. Add a crosslinking agent to the rubber compound I, and double-roll mixing at room temperature to prepare the mixture II;

C. Mix polyolefin, compatibilizer and antioxidant at high speed to obtain mixture III;

D. Add the mixture III from the main feeding port of the co-rotating twin-screw extruder, and the mixture II is forced to be fed from the second zone of the co-rotating twin-screw extruder through the rubber extruder, and passes through the co-rotating twin-screw extruder Dynamic vulcanization extrusion granulation to prepare halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer.

The aspect ratio L/D of the co-rotating twin-screw extruder is above 42, and the extrusion temperature of the twin-screw extruder is: 120°C-160°C in the feeding section, 160°C-190°C in the compression section, and 160°C-190°C in the homogenization section 180°C~220°C, 180°C~220°C for the die part of the die, and the screw speed is 100~400r/min.

Calculated by weight percentage, the present invention includes 100 parts of silicone rubber, 50-100 parts of polyolefin, 10-50 parts of white carbon black, 100-200 parts of halogen-free flame retardant, 1-5 parts of compatibilizer, 1-2 parts Antioxidant, 1-3 parts of cross-linking agent, 1-5 parts of hydroxyl silicone oil, 0.5-1 part of silane coupling agent; the invention can be widely used in automobiles, electronic appliances, cables and wires, medical equipment, architectural decoration, etc. field, since the halogen-free flame retardant in the present invention is a compound of aluminum hydroxide and (or) magnesium hydroxide and zinc borate, melamine cyanurate or microencapsulated red phosphorus, the antioxidant used simultaneously Tetrakis[methyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propane N-octadecanyl acid esters or their respective complexes with tris[2,4-di-tert-butylphenyl]phosphite in a ratio of 1 to 2:1 make the present invention not only halogen-free, but also environmentally friendly , and the flame retardant effect is good, and its oxygen index can reach up to 38.

specific implementation

The present invention will be further described in detail below in combination with specific embodiments, so as to help those skilled in the art understand the present invention.

Example 1

A dynamically vulcanized halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer, the raw material of which comprises the following components calculated in parts by weight:

100 parts of methyl vinyl silicone rubber raw rubber, 70 parts of low-density polyethylene, 40 parts of fumed silica, 170 parts of aluminum hydroxide, 2 parts of silane-grafted LDPE, tetrakis[methyl-β-(3,5- 2 parts of di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 3 parts of di-tert-butyl peroxide, 1 part of methyltriethoxysilane, and 2 parts of hydroxyl silicone oil.

The preparation method comprises the following preparation steps:

A. Mix silicone rubber raw rubber, white carbon black, flame retardant, hydroxy silicone oil, and silane coupling agent in a kneader at 150±2°C to obtain the mixed rubber I;

B. Add a crosslinking agent to the rubber compound I, and double-roll mixing at room temperature to prepare the mixture II;

C. Mix polyolefin, compatibilizer and antioxidant at high speed to obtain mixture III;

D. Add the mixture III from the main feeding port of the co-rotating twin-screw extruder, and the mixture II is forced to be fed from the second zone of the co-rotating twin-screw extruder through the rubber extruder, and passes through the co-rotating twin-screw extruder Dynamic vulcanization extrusion granulation to prepare halogen-free flame-retardant silicone rubber/polyolefin thermoplastic elastomer.

The extrusion temperature of the co-rotating twin-screw extruder is: 120°C in the feeding section, 160°C in the compression section, 190°C in the homogenizing section, 190°C in the nose and die section, and the screw speed is 200r/min.

Example 2

100 parts of methyl vinyl silicone rubber raw rubber, 100 parts of high-density polyethylene, 10 parts of precipitated silica, 200 parts of magnesium hydroxide, 1 part of silane grafted LLDPE, β-(3,5-di-tert-butyl- 1.5 parts of n-octadecyl 4-hydroxyphenyl)propionate, 3 parts of dicumyl peroxide, 0.5 parts of γ-(methacryloyloxy)propyltrimethoxysilane, and 5 parts of hydroxyl silicone oil.

The preparation method is the same as in Example 1, wherein, the extrusion temperature of the co-rotating twin-screw extruder is: feeding section 160°C, compression section 190°C, homogenizing section 220°C, nose and die part 220°C, screw speed 400r/min.

Example 3

100 parts of methyl vinyl silicone rubber raw rubber, 60 parts of polyolefin resin (wherein, olefin resin is a composition of 20 parts of linear low-density polyethylene and 40 parts of high-density polyethylene), 10 parts of fumed white carbon black, no 120 parts of halogen flame retardant system (halogen-free flame retardant system is a compound of aluminum hydroxide and microencapsulated red phosphorus, including: 100 parts of aluminum hydroxide, 20 parts of microencapsulated red phosphorus), 5 parts of compatibilizer ( The compatibilizer is the composition of 1 part of silane-grafted LDPE and 4 parts of silane-grafted LLDPE), 1 part of antioxidant (the antioxidant is tetrakis[methyl-β-(3,5-di-tert-butyl-4-hydroxyl phenyl) propionate] pentaerythritol ester and tris [2,4-di-tert-butylphenyl] phosphite in a ratio of 1:1), 1 part of cross-linking agent (the cross-linking agent is diperoxide 0.8 part of cumene and 2,5-dimethyl-2, the composition of 0.2 part of 5-di-tert-butylperoxyhexane, 0.5 part of silane coupling agent (silane coupling agent is vinyltriethoxy 0.1 parts of silane and 0.4 parts of γ-(2,3-glycidoxy)propyltrimethoxysilane), 2.5 parts of hydroxyl silicone oil.

The preparation method is the same as in Example 1, wherein, the extrusion temperature of the co-rotating twin-screw extruder is: feeding section 140°C, compression section 180°C, homogenization section 185°C, die part 190°C, screw speed 250r/min.

Example 4

100 parts of raw methyl vinyl silicone rubber, 80 parts of polyolefin resin (wherein, olefin resin is a combination of 10 parts of low-density polyethylene, 10 parts of linear low-density polyethylene, 40 parts of high-density polyethylene and 20 parts of polypropylene substance), 20 parts of precipitated white carbon black, 150 parts of halogen-free flame retardant system (halogen-free flame retardant system is a compound of 70 parts of aluminum hydroxide, 70 parts of magnesium hydroxide and 10 parts of melamine cyanurate), 1.3 parts of compatibilizer (the compatibilizer is the composition of 0.5 part of silane grafted LDPE, 0.5 part of silane grafted LLDPE and 0.3 part of silane grafted HDPE), 2 parts of antioxidant (the antioxidant is β-( 3,5-di-tert-butyl-4-hydroxyphenyl) n-octadecyl propionate and tris[2,4-di-tert-butylphenyl]phosphite in a ratio of 2:1) 1 part of crosslinking agent (crosslinking agent is 0.2 part of di-tert-butyl peroxide, 0.2 part of dicumyl peroxide and 2,5-dimethyl-2, 0.6 part of 5-di-tert-butylperoxyhexane part composition), 0.7 part of silane coupling agent (silane coupling agent is 0.1 part of vinyltriethoxysilane, 0.1 part of γ-(methacryloyloxy)propyltrimethoxysilane and γ-(2 , a composition of 0.5 parts of 3-glycidoxy)propyltrimethoxysilane), 5 parts of hydroxyl silicone oil.

The preparation method is the same as in Example 1, wherein, the extrusion temperature of the co-rotating twin-screw extruder is: feeding section 130°C, compression section 170°C, homogenization section 180°C, die part 180°C, screw speed 100r/min.

Example 5

100 parts of methyl vinyl silicone rubber raw rubber, 50 parts of polypropylene, 50 parts of fumed silica, 100 parts of halogen-free flame retardant system (the halogen-free flame retardant system is 70 parts of aluminum hydroxide, 20 parts of magnesium hydroxide and 10 parts of zinc borate), 3 parts of compatibilizer (the solubilizer is a composition of 0.2 parts of silane-grafted LDPE and 2.8 parts of silane-grafted HDPE), tetrakis[methyl-β-(3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate] 1.2 parts of pentaerythritol ester, 2 parts of 2,5-dimethyl-2,5-di-tert-butylperoxyhexane, γ-(2,3 - 0.8 parts of glycidoxy)propyltrimethoxysilane, 3 parts of hydroxyl silicone oil.

The preparation method is the same as in Example 1, wherein, the extrusion temperature of the co-rotating twin-screw extruder is: feeding section 145°C, compression section 175°C, homogenizing section 185°C, head and die part 200°C, screw speed 300r/min.

Example 6

100 parts of methyl vinyl silicone rubber raw rubber, 90 parts of polyolefin resin (the olefin resin is linear low density polyethylene), 15 parts of fumed silica, 185 parts of halogen-free flame retardant system (the halogen-free flame retardant system is hydrogen 160 parts of magnesium oxide and 25 parts of melamine cyanurate), 4 parts of silane grafted LLDPE, 1 part of antioxidant (the antioxidant is β-(3,5-di-tert-butyl-4-hydroxybenzene Base) a compound of n-octadecyl propionate and tris[2,4-di-tert-butylphenyl]phosphite in a ratio of 1.5:1), 2,5-dimethyl-2,5- 1 part of di-tert-butyl peroxide hexane, 0.9 parts of silane coupling agent (silane coupling agent is 0.1 part of γ-(methacryloyloxy)propyltrimethoxysilane and 0.1 part of γ-(2,3-epoxy Propoxy) propyltrimethoxysilane 0.8 parts composition), 3.1 parts of hydroxyl silicone oil.

The preparation method is the same as in Example 1, wherein, the extrusion temperature of the co-rotating twin-screw extruder is: feeding section 150°C, compression section 185°C, homogenizing section 210°C, die part 210°C, screw speed It is 350r/min.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made with the features and principles described in the claims of the present invention should be included in the present invention. within the scope of the claims.

The obtained product is tested, and the obtained performance data are shown in Table 1.

Table 1

It can be seen from Table 1 that after testing, the oxygen index of the embodiment of the present invention is at least 32 and the highest is 38. It can be seen that the present invention has very good flame retardancy while ensuring other performance indicators.

Claims (9)

1. a dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO is characterized in that, its raw material comprises the following component of calculating by weight:

100 parts of methyl vinyl silicon kautschuks;

50～100 parts of polyolefin resines;

10～50 parts of WHITE CARBON BLACKs;

100～200 parts of halogen-free flame-retardant systems;

1～5 part of expanding material;

1～2 part in oxidation inhibitor;

1～3 part of linking agent;

0.5～1 part of silane coupling agent;

1～5 part of hydroxy silicon oil;

Said polyolefin resin is one or more the mixture in new LDPE (film grade), linear low density polyethylene, high density polyethylene(HDPE) or the Vestolen PP 7052; Said WHITE CARBON BLACK is thermal silica or precipitated silica; Said expanding material is a silane grafted polyolefin resin; Said linking agent is di-t-butyl peroxide, Di Cumyl Peroxide 99,2,5-dimethyl--2, the one or more combination thing in the 5-di-t-butyl hexane peroxide; Said methyl vinyl silicon kautschuk, the x of its vinyl are 0.05%～0.5%.

2. dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 1; It is characterized in that; Said halogen-free flame-retardant system is the compound of white lake and zinc borate, melamine cyanurate or micro encapsulation red phosphorus, and the components by weight of this system is:

100 parts in white lake;

0～20 part in zinc borate, melamine cyanurate or micro encapsulation red phosphorus;

Wherein, zinc borate, melamine cyanurate or micro encapsulation red phosphorus are not 0.

3. dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 1; It is characterized in that; Said halogen-free flame-retardant system is the compound of Marinco H and zinc borate, melamine cyanurate or micro encapsulation red phosphorus, and the components by weight of this system is:

100 parts of Marinco Hs;

0～20 part in zinc borate, melamine cyanurate or micro encapsulation red phosphorus;

Wherein, zinc borate, melamine cyanurate or micro encapsulation red phosphorus are not 0.

4. dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 1; It is characterized in that; Said halogen-free flame-retardant system is the compound of white lake and Marinco H and zinc borate, melamine cyanurate or micro encapsulation red phosphorus, and the components by weight of this system is:

100 parts of white lake and Marinco Hs;

0～20 part in zinc borate, melamine cyanurate or micro encapsulation red phosphorus;

Wherein, zinc borate, melamine cyanurate or micro encapsulation red phosphorus are not 0; Weight ratio between said white lake and the Marinco H 1: 0.2～1.

5. dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 1; It is characterized in that; Said oxidation inhibitor is four [methyl-β-(3; The 5-di-tert-butyl-hydroxy phenyl) propionic ester] pentaerythritol ester or β-positive octadecanol ester of (3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid.

6. dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 1; It is characterized in that; Said oxidation inhibitor is four [methyl-β-(3; The 5-di-tert-butyl-hydroxy phenyl) propionic ester] pentaerythritol ester or β-positive octadecanol ester of (3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid respectively with three [2, the 4-di-tert-butyl-phenyl] phosphorous acid ester by weight the compound that is 1～2: 1.

7. dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 1; It is characterized in that; Said silane coupling agent is the one or more combination thing in Union carbide A-162, vinyltriethoxysilane, γ-(methacryloxypropyl) propyl trimethoxy silicane, γ-(2,3-epoxy third oxygen) propyl trimethoxy silicane.

8. the preparation method of a dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO as claimed in claim 1 is characterized in that, comprises being prepared as follows step:

A, with methyl vinyl silicon kautschuk, WHITE CARBON BLACK, halogen-free flame-retardant system, hydroxy silicon oil, silane coupling agent in kneader 150 ± 5 ℃ mixing evenly, make rubber unvulcanizate I;

B, in rubber unvulcanizate I, add linking agent, twin-roll mixing under the normal temperature makes mixtures II;

C, polyolefin resin, expanding material and oxidation inhibitor mixed at high speed is even makes mixtures III;

D, the main spout of mixtures III from parallel dual-screw extruding machine added; Mixtures II is forced to feed through second district of rubber extruding machine from parallel dual-screw extruding machine; Through parallel dual-screw extruding machine dynamic vulcanization extruding pelletization, make halogen-free anti-flaming silicon rubber/TPO.

9. the preparation method of dynamic vulcanization halogen-free anti-flaming silicon rubber/TPO according to claim 8; It is characterized in that; The extrusion temperature of twin screw extruder described in the step D is: 120 ℃～160 ℃ of feeding sections, 160 ℃～190 ℃ of compression sections, 180 ℃～220 ℃ of homogenizing zones; 180 ℃～220 ℃ of machine head port mould parts, screw speed is 100～400r/min.