FI114479B - Compatible polymer composition comprising vinyl aromatic polymer, polyolefin and two linear copolymers - Google Patents

Abstract

A compsn. contains: (A) a compsn. contg. a vinylaromatic polymer, (B) a polyolefin, (C) a linear copolymer contg. a vinyl-aromatic monomer and a conjugated diene with more than 50% of units from the vinylaromatic monomer, and (D) a linear copolymer contg. a vinylaromatic monomer and a conjugated diene, with more than 50% of units from the diene.

Description

114479

This invention relates to a composition comprising a vinyl aromatic polymer and a polyolefin polymer.

Vinyl aromatic polymers and polyolefins are usually incompatible and, if simply mixed together, will not result in materials having good mechanical properties. Addition of compatibilizers to the blend of these two polymer types has already been proposed. EP 0402340 discloses a bipolar linear styrene / butadiene copolymer and a tri-block radial styrene / butadiene copolymer as a compatibilizer. EP 0447806 discloses a tripartite linear styrene / butadiene copolymer as a compatibilizer. EP 0545181 discloses a three-block linear styrene / butadiene copolymer of formula S1-B-S2, wherein the two styrene blocks, S1 and S2, represent at least 50% of different molecular weights as a compatibilizer. EP 0554787 discloses blends of poly, 'styrene, polyolefin and block copolymer blend. Salmon: The size copolymer is star-shaped, non-linear in structure. EP 0580051 discloses: polystyrene-polyolefin compositions using a partially blocked copolymer of styrene (45-85% by weight) and isoprene as a compatibilizer.

The present invention discloses as a compatibilizer: - a linear copolymer of vinylaromatic monomer and conjugated diene containing more than 50% by weight of units derived from vinylaromatic monomer, and - vinylaromatic monomeric and monomeric 30 containing more than 50% by weight of units derived from conjugated diene.

• The compatible polymer composition of the invention has excellent impact resistance and tear resistance as well as good rigidity (modulus of elasticity). In addition, it is easy to recycle, easy to use because of its flow index of 2 114479, it is suitable for both injection molding and extrusion / thermoforming, and it is resistant to grease.

The compatible polymer composition of the invention comprises: 10 to 90% by weight of Preparation A obtained by polymerization or copolymerization of at least one vinyl aromatic monomer, 5 to 50% by weight of polyolefin B obtained by polymerization or copolymerization of at least one olefin. The polymer composition is characterized in that it comprises: 1-20% by weight of a linear copolymer C of a vinylaromatic monomer and conjugated diene, containing more than 50% by weight of units derived from a vinylaromatic monomer, 1-20 to 10% by weight of a vinylaromatic monomer and linear copolymer D containing more than 50% by weight of units derived from conjugated diene.

Preparation A is obtained by polymerization or copolymerization of at least one vinyl aromatic monomer.

Preparation A may be obtained by polymerization or copolymerization of at least one vinyl aromatic monomer in the presence of a rubber.

By rubber is meant one commonly used to improve the impact resistance of vinyl aromatic polymers or copolymers. Usually they are po-. polymers or copolymers obtained by polymerization or copolymerization from at least one conjugated diene, such as polybutadiene, polyisoprene, and elastomer-type styrene / butadiene block copolymers, also called '·:: SBR gums (styrene-butadiene).

• ·. The rubber in Composition A is usually present as nodules or particles. The preparation * * <A can be obtained using any polymerization process, for example radical, anionic, bulk, solution or suspension polymerization, and may be. continuous or batch type. As a minimum in the preparation of preparation A; the comonomer of one of the vinylaromatic monomers may be selected from the group consisting of acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, alkyl ester having: * · ': an alkyl group containing from 1 to 4 carbon atoms, an N-alkyl maleimide having an 4 carbon atoms and N-phenylmaleimide.

* ·: When preparation A contains rubber, it is usually present in an amount of 2 to 25% by weight. It is understood that preparation A may comprise more than one vinyl aromatic polymer or copolymer, one or more of which may contain rubber.

3, 114479

Polyolefin B is obtained by polymerization or copolymerization of at least one olefin. Thus, both the polymer and the copolymer can be used. By olefin is meant those containing from two to twenty carbon atoms, and in particular alpha olefins of this group. Among the olefins, there may be mentioned ethylene, propylene, 5-butene, 4-methyl-1-pentene, 1-octene, 1-hexene, 3-methyl-1-pentene, 3-methyl-1-butene, 1-decene, tetradecene and mixtures thereof.

A possible comonomer of at least one olefin may be, for example, a vinyl ester such as vinyl acetate or vinyl propionate, acrylic acid, acrylic or alkyl acrylic acid such as methyl acrylate or methyl methacrylate.

Polyolefin B may be polyethylene having a medium to very low molecular weight (0.9 <density <0.95) or high density polyethylene (density> 0.95).

Polyolefin B may be a polypropylene or an ethylene / propylene copolymer, a block copolymer or a statistical copolymer.

Preferably, polyolefin B should be polyethylene.

Copolymers C and D are obtained by copolymerizing at least one vinyl aromatic monomer and at least one conjugated diene. These copolymers can be selected from those whose structure may be represented by the formulas S1-B1-S2 or Sr (B / S) n or Sr (B / S) -S2 or SrBr (BS) n or SrBi-S2-B2, wherein S1 and S2 : '; are blocks derived from a vinyl aromatic monomer, B1 and B2 are conjugated. In the case of the 20-conjugated diene-derived blocks, B / S is a block of a copolymer derived from a vinylaromatic monomer: Y: conjugated diene and n is an integer other than zero.

;; Preferably, copolymer C should comprise at least three blocks.

*

Preferably, copolymer D should comprise at least three blocks.

• ;;; Typically, Copolymer C has a weight average molecular weight of 30,000 to 300,000, preferably from 80,000 to 150,000, as measured by gel permeation chromatography on the basis of a poly: '·': styrene gradient.

Typically, copolymer D has a weight average molecular weight of 5000 to 200000, γ j preferably 8000 to 80,000, as measured by gel permeation chromatography on a polystyrene basis.

4, 114479

Also, the case where one or more statistical spacers, a copolymer of vinylaromatic monomer and conjugated diene, is placed between the polystyrene and polybutadiene blocks of the above formulas. In addition, one or more of these blocks may be formed from two sub-blocks, which are then joined together by a difunctional coupling agent, as is customary in anion polymerization techniques.

The vinyl aromatic monomer which may be used in components A, C and D may be styrene, styrene substituted for the vinyl group by an alkyl group such as alpha-methylstyrene or alphaethylstyrene, styrene substituted for the ring by 10-alkylene styrene substituted for the ring by halogen such as 2,4-dichloro-styrene, styrene substituted by both a halogen and an alkyl group such as 2-chloro-4-methylstyrene, as well as vinyl anthracene. The most preferred vinyl aromatic monomer is styrene.

Conjugated diene which may be used in Components C and D refers to conjugated dienes containing 4-8 carbon atoms such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, piperylene and mixtures thereof.

Preferably, the composition of the invention comprises:

. 50 to 80% by weight of Preparation A

20 to 10 to 35% by weight of polyolefin B

- 4 to 15% by weight of copolymer C '·' · * - 2 to 13% by weight of copolymer D.

• a • a; ; The composition of the invention may comprise additives which are conventional for this. ·; ·. type of composition, for example plasticizers such as mineral oils, butyl stearate or dioctyl phthalate, stabilizers such as antioxidants eg phenol. substituted by an alkyl group such as ditertiobutyl parresresol, or a phosphite such as * ;;; trinonyylifenyylifosfiitti. The additive may also be an electrospinning agent, a blowing agent or a pigment. It is also possible that an additive is included in one of the ingredients of the composition of the invention prior to the preparation of the composition. It is obvious that when the composition according to the invention is intended. in the food industry, additives which are toxic are used; suitable for the job.

; * * * »5 114479

The composition of the invention may be obtained by melt blending its various components using techniques commonly used to effect such a composition.

All types of mixers can be used with one or two screws operating at 150-260 ° C.

The composition of the invention can be extruded, compressed, sprayed or transformed into granules, the latter being for the preparation of any kind of articles by injection, extrusion or thermoforming. The composition according to the invention can be transformed with devices commonly used for the transformation of polymers, especially polystyrene, preferably at a temperature of 150-260 ° C.

In the following examples, the properties of the compositions were determined by the following techniques: - flow index at 200 ° C for 5 kg load: ISO 1133 standard, 15 - Vicat 1 kg standard: ISO 306A standard, - flexural modulus: standard ISO 178, stretchability: standard ISO R527, - Izod notch impact strength: standard ISO 180/1 A.

In the examples, the ingredients indicated by the letters A, B, C and D are: • · .. 20 A: Impact polystyrene, trade mark LACQRENE 5240, contains 9.5% by weight; Y: polybutadiene as nodules, flow index 2.5 g / 10 min (5 kg) load at 200 ° C).

B: Low density polyethylene (density = 0.917), flow index 2.5 g / 10 min * (2.16 kg at 190 ° C). This ingredient is sold by ELF ATOCHEM under the trademark 25 LACQTENE HX5010.

. · *. C: A linear tri-block styrene / butadiene copolymer, the structure Y of which can be generally represented by the formula S1-B-S2, wherein S1 and S2 are each a polystyrene Y block and B is a polybutadiene block. This copolymer contains 73% by weight of units derived from .Y styrene and has a weight average molecular weight of *: 30,000,000, as measured by gel permeation chromatography on a polystyrene gradient. There is a small statistical intermediate block between blocks S1, and B, on the one hand, and blocks B and S2, on the other. Block B is implemented using two polybutadiene sub-blocks, 6114479, which are connected by a difunctional coupling agent. This ingredient is sold by FINA under the trademark FINACLEAR 520.

D: A linear tri-block styrene / butadiene copolymer having the structure generally represented by S1-B-S2, wherein S1 and S2 are each a polystyrene-5 block and B is a polybutadiene block. This polymer contains 70% by weight of units derived from butadiene and has a weight average molecular weight of 20,000, as measured by gel permeation chromatography on a polystyrene gradient. Block B is implemented using two polybutadiene sub-blocks connected by a difunctional coupler. This ingredient is sold by SHELL custom 10 with the KRATON TR 1102 brand.

Examples 1-4

Mix A, B, C and D in the form of granules at ambient temperature in the proportions given in Table 1. Addition of 1000 ppm antioxidant. The mixture is extruded at about 200 ° C through a single screw Samafor E45 machine and granulated from the nozzle after outlet. The specimens for mechanical tests are then prepared from granules by injection at 215 ° C. The properties of the resulting materials are summarized in Table 1.

Table 1: [7 "EXAMPLE N: 0

Composition_____ ONE. 12 3 4 (in value) (in value) A_wt% 68 68 68 68 B_wt% 15 15 15 15 C_wt% 5 17 0 12 _D_wt% 12 0 17 5

Properties Flow Index g / 10min 4 3.6 5.2 3.8 ··; 'Vicat Point ° C__99.5 101.5 97.5 100

Bending Module - MPa__1200 1420 1070 1350

Tensile strength MPa__21 22 19 22

Elongation at fracture% __ 100 90 85 100 \; IZOD-lovi- kJ / m2 43 31 27 42 ',, | impact strength 23 ° C ______ IZOD-lovi- kJ / m2 26 9 21.5 22 __ impact strength -30 ° C ______

Claims (11)

1. Compatible polymer composition containing: -10-90% by weight of a preparation A derived from the polymerization or copolymerization of at least one vinyl aromatic monomer, - 5-50% by weight of a polyolefin B derived from the polymerization or copolymerization of at least one olefin, characterized in that it contains: -1-20% by weight of a linear copolymer C of a vinyl aromatic monomer and of a conjugated diene containing more than 50% by weight units derived from the vinyl aromatic monomer, -1 -20% by weight of a linear copolymer D of a vinyl aromatic monomer and of a conjugated diene containing more than 50% by weight units derived from the conjugated diene. Composition according to claim 1, characterized in that the copolymer C contains. 20 contains between 60 and 90% by weight of units derived from the vinyl aromatic monomer. . Composition according to claim 1 or 2, characterized in that the copolymer:: D contains between 60 and 90% by weight of units derived from the conjugate; : serve councils. '* 25 Composition according to any of claims 1-3, characterized in that the copolymer C comprises at least 3 blocks. I t. ·. Composition according to any one of claims 1-4, characterized in that the copolymer D comprises at least 3 blocks. Composition according to any of claims 1-5, characterized in that the polyolefin B is a polyethylene. i » Composition according to any one of claims 1-6, characterized in that the composition A comprising a vinyl aromatic polymer also comprises a rubber. 114479 Composition according to claim 7, characterized in that the rubber is a polybutadiene. Composition according to claim 7 or 8, characterized in that the rubber is present in the preparation A from 2 to 25% by weight. Composition according to any of claims 7-9, characterized in that the composition A is impact resistant polystyrene. Composition according to any one of the preceding claims, characterized in that it comprises - 50-80% by weight of preparation A 10 - 10-35% by weight of polyolefin B - 4-15% by weight of copolymer C - 2-13 % by weight of copolymer D. * II tt • 1 f I t I