EA040086B1 - RUBBER-MODIFIED MONOVINYLAROMATIC POLYMER, METHOD FOR ITS PRODUCTION, PRODUCT CONTAINING RUBBER-MODIFIED MONOVINYLAROMATIC POLYMER, AND METHOD FOR PRODUCING THE SPECIFIED PRODUCT - Google Patents

Description

Technical field

The invention relates to rubber-modified monovinyl aromatic polymers, such as high impact polystyrene (HIPS) compositions, which have improved stress crack resistance, and to a process for preparing such compositions. The present invention also relates to products obtained from them.

Prior Art

Thermoformed articles such as food containers that make up impact resistant (i.e. rubber-modified polystyrene (HIPS), typically rubber-modified monovinyl aromatic polymer) are prone to stress cracking when they come into contact with fats and oils present in organic foods. products. Products made from HIPS are also subject to stress cracking when they come into contact with organic blowing agents such as halocarbons containing fluorine and chlorine. These polymers are commonly found in household products such as refrigerator liners, which can develop cracks when cavities in refrigerators are filled with polyurethane foam as a result of the use of blowing agent in foam formation.

Various approaches have been taken to obtain rubber-reinforced monovinyl aromatic polymers having good environmental stress crack resistance (ESCR). These include the use of multi-layer sheet technology, increasing the amount of rubber, increasing the volume of the gel phase, optimizing the particle size of the rubber, controlling the degree of crosslinking of the rubber, optimizing the process, using additives such as polypropylene, polybutylene, ethylene-alpha-olefin copolymers, and using high molecular weight rubber. .

A few years ago it was found that the addition of 1 to 3 wt.% polyisobutene (PIB) in HIPS enhances the properties of ESCR. However, ongoing research to improve stress crack resistance has focused on other oligomers.

US 2004/0001962 discloses the use of polyisobutylene, certain polymerized alpha-olefins (PAOs) containing at least 10 carbon atoms, atactic polypropylene, or a polyolefin copolymer, with the optional use of mineral oil in a HIPS formulation, to increase ESCR. The selected PAO has a high dynamic viscosity in the range of 100 to 500 centipoise (cP) (100 to 500 mm ² /s) or 200 to 1000 cP (200 to 1000 mm ² /s) at 99°C when determined according to the standard ASTM D-3236. However, the PAO used in the examples is VYBAR® 825. According to WO2010033489, the dynamic viscosity of VYBAR® 825 is 54 cP (54 mm ² /s) at 98.9°C and 530 cP (530 mm ² /s) at 37.8°C (ASTMD-3236).

WO 2010033489 discloses compositions containing rubber-modified monovinylidene aromatic polymers and effective amounts of polymerized alpha olefins (PAO) having a dynamic viscosity (ASTM D-3236) of about 40 to about 500 cps (about 40 to about 500 mm ² / c) at 40°C. The examples disclose the use of PAO (mPAO) prepared in the presence of a metallocene catalyst in an amount of 3.5% by weight based on the weight of the final polymer composition. An increase in ESCR has been found for compositions containing mPAO, in which the kinematic viscosity is from 65 mm ² /s (Durasyn® 170) to 400 mm ² /s (Durasyn® 174) at 40°C. Less effective have been those with increased mPAO viscosities, such as mPAO (Durasyn® 180) with a kinematic viscosity above 1000 mm ² /s at 40°C.

It should be recalled here that the dynamic viscosity of a fluid expresses its resistance to shear flow, in which adjacent layers move parallel to each other at different speeds, and that kinematic viscosity is the ratio of dynamic viscosity to fluid density.

There is an ongoing interest in finding solutions to improve the ESCR performance and the overall combination of properties of HIPS and similar materials without compromising the degree of freedom in the polymer manufacturing and molding process or degrading the qualities of the polymer itself.

In order to increase the ESCR of rubber-modified monovinyl aromatic polymers, there is interest in finding possible economical solutions, such as reducing the additive content to the lowest possible level.

Thus, it is an object of the present invention to provide rubber-modified monovinyl aromatic polymer compositions having improved stress crack resistance.

The essence of the invention

According to a first aspect, the present invention relates to a rubber-modified monovinyl aromatic polymer comprising, by weight % or more, of a monovinyl aromatic polymer matrix based on the total weight of the rubber-modified monovinyl aromatic polymer,

- 1 040086 from 2 to 12 wt.% of at least one rubber based on the total weight of the rubber-modified monovinyl aromatic polymer and from 0.1 to 3.4 wt.% of poly-alpha-olefins (mPAO) obtained in the presence of a metallocene catalyst from the total weight a rubber-modified monovinyl aromatic polymer, wherein the mPAOs have a kinematic viscosity of at least 950 mm ² /s at 40°C and not more than 2000 mm ² /s at 40°C when measured according to ISO 3104.

Surprisingly, the present inventors have found that high viscosity mPAOs, even at low concentrations (e.g., less than 3.4% by weight of the rubber-modified monovinyl aromatic polymer) lead to improved ESCR performance, while lower mPAO viscosities are less efficient.

Additionally, according to the present invention, one or more of the following features may preferably be used.

The rubber-modified monovinyl aromatic polymer is a rubber-modified monovinyl aromatic homopolymer or a rubber-modified monovinyl aromatic copolymer.

mPAO is present in an amount of at least 0.3% by weight based on the total weight of the rubber-modified monovinyl aromatic polymer, preferably at least 0.4% by weight, preferably at least 0.8% by weight, preferably at least 1 .0 wt.%, more preferably at least 1.1 wt.%.

mPAO is present in an amount of not more than 3.3% by weight based on the total weight of the rubber-modified monovinyl aromatic polymer, preferably not more than 3.2% by weight, preferably not more than 3.0% by weight, preferably not more than 2 .8 wt.%, preferably not more than 2.5 wt.%, more preferably not more than 2.0 wt.%, even more preferably not more than 1.8 wt.%, and most preferably not more than 1, 5 wt%.

The kinematic viscosity of mPAO is at least 1000 mm ² /s at 40°C and preferably at least 1100 mm ² /s at 40°C when measured according to ISO 3104.

The kinematic viscosity of mPAO is not more than 1800 mm ² /s at 40°C, preferably not more than 1500 mm ² /s at 40°C, and more preferably not more than 1400 mm ² /s at 40°C when measured according to the ISO standard 3104.

The kinematic viscosity of mPAO is at least 100 mm ² /s at 100°C, preferably at least 110 mm ² /s at 100°C and/or the kinematic viscosity of mPAO is not more than 200 mm ² /s at 100°C and preferably not more than 190 mm ² /s at 100°C when measured according to ISO 3104.

The mPAO viscosity index is at least 200 when determined according to ISO 2909.

mPAO has a pour point of less than -20°C, preferably less than 25°C, more preferably less than -30°C and most preferably less than -35°C when determined according to ISO 3016.

mPAOs are alpha-olefins containing at least 6 carbon atoms and not more than 20 carbon atoms.

mPAO is an oligomer based on one or more alpha-olefin monomers selected from the group consisting of hexene, octene, decene, dodecene and tetradecene.

The polymer additionally contains a plasticizer, preferably mineral oil and/or polyisobutene, in an amount ranging from 0.1 to 6 wt.% by weight of the composition, preferably from 0.5 wt.% to 3.5 wt.%, more preferably 1.5 to 3.0 wt.%.

The polymer additionally contains a mineral oil plasticizer having a kinematic viscosity at 40°C of 65 to 100 mm ² /s according to ISO 3104, preferably 65 to 75 mm ² /s.

The weight ratio of plasticizer to mPAO in said polymer is not more than 1:50, preferably not more than 1:10, more preferably not more than 1:4, more preferably not more than 1:0.75.

The weight ratio of plasticizer to mPAO in said polymer is at least 1:0.02, preferably at least 1:0.2.

The rubber-modified monovinyl aromatic polymer is rubber-modified polystyrene (HIPS) or rubber-modified poly(styrene-acrylonitrile) (ABS).

The rubber-modified monovinyl aromatic polymer contains 2 to 8 wt % of one or more rubbers based on the total weight of the rubber-modified monovinyl aromatic polymer.

The rubber-modified monovinyl aromatic polymer contains a rubber selected from the group consisting of polybutadiene, polyisoprene, copolymers of butadiene and/or isoprene with styrene, and natural rubber.

The weight average molecular weight (M _w ) of the monovinyl aromatic polymer matrix is at least 130,000 g/mol, preferably at least 140,000 g/mol, and more preferably at least 150,000 g/mol, as determined by gel permeation chromatography.

The molecular weight distribution of the monovinyl aromatic polymer matrix is at least 1.8, preferably at least 2.1.

The molecular weight distribution of the monovinyl aromatic polymer matrix is at most 5.0, more preferably at most 4.0, and most preferably at most 3.5.

According to a second aspect, the present invention relates to a process for preparing a composition comprising a rubber-modified monovinyl aromatic polymer defined according to the first aspect of the present invention, said method comprising the step of polymerizing a reaction mixture of a monovinyl aromatic monomer, one or more rubbers, and one or more metallocene-catalyzed poly- alpha-olefins (mPAO), and wherein one or more mPAO is present in an amount ranging from 0.1 to 3.4 wt.% of the total mass of the mixture.

Preferably, the method according to the present invention comprises the following steps:

a) introducing a reaction mixture containing at least one monovinyl aromatic monomer, at least one rubber, at least one mPAO having a kinematic viscosity of at least 950 mm ² /s at 40°C and not more than 2000 mm ² /s at 40° C. as measured according to ISO 3104, and an optional free-radical polymerization initiator in the phase inversion reactor and polymerization of the reaction mixture in the phase inversion reactor to a level above the inversion point of the reaction mixture to obtain a first polymerization mixture containing at least rubber and mPAO;

b) introducing the first polymerization mixture into a polymerization reactor to form a second polymerization mixture;

c) optional introduction of the second polymerization mixture into at least one subsequent reactor for post-inversion polymerization of the third polymerization mixture, in addition, the reaction mixture contains at least one monovinyl aromatic monomer, at least one rubber and at least one mPAO in effective proportions to obtain a rubber-modified monovinyl aromatic polymer containing:

wt.% or more of the monovinyl aromatic polymer matrix based on the total weight of the rubber-modified monovinyl aromatic polymer, from 2 to 12 wt.% of at least one rubber based on the total weight of the rubber-modified monovinyl aromatic polymer, and from 0.1 to 3.4 wt.% obtained in the presence of a metallocene catalyst for poly-alpha-olefins (mPAO) based on the total weight of the rubber-modified monovinyl aromatic polymer.

Preferably, step (a) is carried out in two or more steps, including:

a1) introducing a reaction mixture containing at least one monovinyl aromatic monomer, at least one rubber, at least one mPAO and an optional free radical polymerization initiator into a pre-inversion reactor and polymerizing the reaction mixture in the reactor to a level below the inversion point of the reaction mixture to obtain prepolymerization mixture;

a2) introducing the prepolymerization mixture into the phase inversion reactor and polymerizing the prepolymerization mixture to a level above the inversion point of the prepolymerization mixture to obtain a first polymerization mixture.

To further define the method according to the second aspect of the present invention, or embodiments thereof, one or more of the following features may preferably be used:

mPAO is mixed with rubber and a monovinyl aromatic monomer to form a rubber-modified monovinyl aromatic polymer.

mPAO is added before initiating polymerization or at the start of polymerization.

Prior to post-inversion polymerization, the polymerization reaction takes place in two or more reactors connected in series.

According to a third aspect, the present invention relates to an article containing a polymer defined according to the first aspect of the present invention and/or a polymer obtained according to the second aspect of the present invention.

Preferably the article is selected from films, fibers, sheet structures, molded articles, automotive parts, hoses, refrigerator and other liners, apparel and footwear components and seals, more preferably the product is selected from refrigerator gaskets and automotive parts.

According to a fourth aspect, the present invention provides a method for producing an article according to the third aspect of the present invention, the aforementioned method comprising:

an extrusion and/or thermoforming step for the article, or

- 3 040086 stage of injection molding of the product, using a rubber-modified monovinyl aromatic polymer defined according to the first aspect of the present invention, and/or a polymer obtained according to the second aspect of the present invention.

Brief description of the drawings

The drawing shows the results of a three-point bending test of compositions according to the present invention and comparative compositions.

Detailed disclosure of the invention

For the purpose of the present invention, the following definitions are provided. In the context of this document, the term polymer means a polymeric compound obtained by polymerization of monomers belonging to the same or different types. Thus, the generic term polymer encompasses the term homopolymer, commonly used to refer to polymers derived from monomers of the same type, and the terms copolymer and interpolymer, as defined below.

In the context of this document, the terms copolymer, interpolymer and similar terms mean a polymer obtained by polymerization of monomers of at least two different types. These generic terms cover polymers derived from two or more different types of monomers, ie. terpolymers, tetrapolymers, etc.

In the context of this document, the terms mixture, polymer mixture and similar terms mean a composition consisting of two or more compounds, usually two or more polymers. As used herein, the terms blend and polymer blend also mean reactor blends, for example, where the monomer is polymerized in the presence of the polymer. For example, the mixture may initially be a mixture of the first polymer and one or more monomers, which then polymerize to form the second polymer. The mixture may be miscible or immiscible. The mixture may or may not contain separated phases. The mixture may or may not contain one or more domain configurations as determined by transmission electron spectroscopy, light scattering, X-ray scattering, or any other methods known in the art. Preferred mixtures (ie, preferred reactor mixtures) contain two or more phases. For example, the blend may comprise a first phase containing some or all of the monovinyl aromatic polymer and a second phase containing some or all of the rubber and mPAO.

In the context of this document, the term composition and similar terms mean a mixture or combination of two or more components. The composition of the present invention is a rubber-modified monovinyl aromatic polymer containing a poly-alphaolefin. The composition may contain other polymeric or non-polymeric components (ie, additives) necessary or desirable for the end use of the composition.

The terms containing, contains, as used herein, are synonymous with the terms including, includes, have the meaning of including without limitation, not excluding additional components, elements, or processing steps that have not been listed. The terms containing, contains, and contain also cover the terms consisting of.

Specifying ranges of numeric values by limit values, includes all integers and, where appropriate, fractional numbers within a given range (for example, the range from 1 to 5 can include 1, 2, 3, 4 when describing, for example, the number of elements , and may also include 1.5, 2, 2.75 and 3.80 when describing, for example, measurement results). Specifying ranges of numerical values by means of limit values also includes the limit values themselves (for example, the range from 1.0 to 5.0 includes both points 1.0 and 5.0). Any range of numerical values provided herein is intended to include all subranges within it.

Specific features, structures, characteristics, or embodiments may be combined in any suitable manner, as will be apparent to those skilled in the art from the present disclosure, in one or more embodiments.

Composition

The present invention provides a composition comprising a rubber-modified monovinyl aromatic polymer comprising a wt. % or more of a monovinyl aromatic polymer matrix based on the total weight of the rubber-modified monovinyl aromatic polymer, from 2 to 12 wt. 0.1 to 3.4% by weight of metallocene-catalyzed poly-alpha-olefins (mPAO) based on the total weight of the rubber-modified monovinyl aromatic polymer, the mPAO having a kinematic viscosity of at least 950 mm ² /s at 40° C. and not more than 2000 ^mm2 /s at 40°C when measured according to ISO 3104.

- 4 040086

Monovinyl aromatic polymer matrix

Monovinyl aromatic polymers (i.e., homopolymers and copolymers) are obtained by polymerization of monovinyl aromatic monomers, i.e. any aromatic compounds containing a vinyl group. By way of example, monovinyl aromatic monomers are one or more of styrene, vinyltoluene, alpha-methylstyrene, alpha-ethylstyrene, methyl-4-styrene, methyl-3-styrene, methoxy-4-styrene, hydroxymethyl-2-styrene, ethyl-4 -styrene, ethoxy-4-styrene, dimethyl-3,4-styrene, chloro-2-styrene, chloro-3-styrene, chloro-4-methyl-3-styrene, tert-butyl-3-styrene, dichloro-2,4-styrene , dichloro-2,6-styrene, vinyl-1-naphthalene and vinylanthracene. It is within the scope of the present invention to use more than one monovinyl aromatic monomer. Preferably, the monovinyl aromatic monomer contains or is styrene.

A monovinyl aromatic polymer is a monovinyl aromatic polymer matrix in a rubber-modified monovinyl aromatic polymer. The concentration of monovinyl aromatic monomers (ie, styrene concentration) is preferably about 60 wt% or more, more preferably about 65 wt% or more, more preferably about 70 wt% or more, more preferably about 80 wt% or more , more preferably about 90% by weight or more, and most preferably about 93% by weight or more, based on the total weight of the rubber-modified monovinyl aromatic polymer.

The monovinyl aromatic monomer may be copolymerized with one or more of a variety of other copolymerizable monomers. Preferred comonomers include nitrile monomers such as acrylonitrile, methacrylonitrile and fumaronitrile; (meth)acrylate monomers such as methyl methacrylate or n-butyl acrylate; maleic anhydride and/or n-arylmaleimides such as n-phenylmaleimide, as well as conjugated and non-conjugated dienes and alkyl esters of acrylic or methacrylic acid. Exemplary copolymers are styrene-acrylonitrile (SAN) copolymers.

Typically, the copolymers contain comonomer at a concentration of 0.1 wt.% or more, preferably 1 wt.% or more, more preferably 2 wt.% or more, and most preferably 5 wt.% or more, based on the weight of the copolymer. Typically, the copolymer contains the copolymer at a concentration of 40 wt.% or less, preferably 35 wt.% or less, and most preferably 30 wt.% or less, based on the weight of the copolymer.

In a preferred embodiment, the rubber-modified monovinyl aromatic polymer is rubber-modified polystyrene (HIPS) or rubber-modified poly(styrene-acrylonitrile) (ABS). More preferably, the rubber-modified monovinyl aromatic polymer is rubber-modified polystyrene (HIPS).

The molecular weight of a monovinyl aromatic polymer can be characterized by number average molecular weight (M _n ), weight average molecular weight (M _w ), z-average molecular weight (Mz), molecular weight distribution (M _w /M _n ), or any combination thereof.

The molecular weight of a monovinyl aromatic polymer affects its mechanical strength. According to the present invention, the molecular weight must be high enough so that the composition has good resistance to environmental stress cracking, despite the fact that the rubber is present at a low concentration (constituting no more than 12 wt.% of the total weight of the rubber-modified monovinyl aromatic polymer) and/or that the monovinyl aromatic polymer is typically present at a high concentration (constituting at least 70% by weight of the total weight of the rubber-modified monovinyl aromatic polymer).

In one embodiment, the weight average molecular weight (Mw) of the monovinyl aromatic polymer is at least 130,000 g/mol, preferably at least 140,000 g/mol, and more preferably at least 150,000 g/mol, as determined by gel permeation chromatography. The weight average molecular weight of the monovinyl aromatic polymer must be low enough so that the material can be easily prepared and/or processed. The weight average molecular weight of the monovinyl aromatic polymer may preferably be at most 300,000 g/mol, more preferably at most 280,000 g/mol, more preferably at most 260,000 g/mol, and most preferably at most 240,000 g/mol.

The molecular weight distribution (M _w /M _n ) of the monovinyl aromatic polymer is preferably at least 1.8, more preferably at least 2.0, even more preferably at least 2.1. The molecular weight distribution of the monovinyl aromatic polymer is preferably no more than 4.0, more preferably no more than 3.5, even more preferably no more than 3.0, and most preferably no more than 2.5.

The monovinyl aromatic polymer preferably has a z-average molecular weight (Mz) of at least 250,000 g/mol. The monovinyl aromatic polymer preferably has a z-average molecular weight of not more than 1,000,000 g/mol.

The rubber-modified monovinyl aromatic polymer contains 70 wt% or more of the monovinyl aromatic polymer matrix based on the total weight of the rubber-modified monovin

- 5 040086 nilaromatic polymer and one or more rubbers, preferably 80 wt.% or more monovinyl aromatic polymer matrix, more preferably 90 wt.% or more monovinyl aromatic polymer matrix.

rubber component

The monovinyl aromatic polymer contains at least one rubber (eg, an elastomeric polymer) dispersed in the form of rubber particles in a monovinyl aromatic matrix. The rubber may be any rubber suitable for improving impact and/or environmental stress cracking resistance when present in the monovinyl aromatic polymer. The rubber is preferably an unsaturated rubber polymer or other polymers capable of forming a graft copolymer during polymerization of the monovinyl aromatic polymer.

Exemplary rubbers are, without limitation, ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), polybutadiene, acrylonitrile-butadiene copolymer, polyisoprene, isoprene-acrylonitrile copolymer, styrene-butadiene rubber (SBR), and copolymers. containing styrene blocks and natural rubber. More specifically, the styrenic block-containing copolymers are preferably copolymers containing styrenic blocks and blocks that comprise butadiene, isoprene, or a mixture of butadiene and isoprene. Said block copolymers may be linear block copolymers or star block copolymers, hydrogenated and/or functionalized. Preferably, polybutadiene, polyisoprene, copolymers of butadiene and/or isoprene with styrene and natural rubber are selected as rubber.

The rubber in the rubber-modified polymers of the present invention is typically present in an amount of not more than 15% by weight based on the total weight by weight of the rubber-modified monovinyl aromatic polymer, preferably not more than 12% by weight, more preferably not more than 10% by weight, still more preferably not more than 8 wt.%. Typically, the rubber is present in an amount of at least 2% by weight of the total weight of the rubber-modified monovinyl aromatic polymer, preferably at least 3% by weight, more preferably at least 4% by weight, and even more preferably at least 5% by weight. wt.%. Generally, HIPS products contain less rubber than ABS products.

In order to provide sufficient initial impact strength and sufficient ESCR, the rubber particles in the compositions of the present invention typically have a volume median diameter D50(v) of at least 1 micrometer (μm), preferably at least 2 μm, and most preferably at least 3 µm and generally not more than 12 µm, preferably not more than 10 µm, even more preferably not more than 9 µm, preferably not more than 8 µm.

Poly-alpha-olefin (mPAO) component obtained in the presence of a metallocene catalyst

The rubber-modified monovinyl aromatic polymer further comprises at least one mPAO in the dispersed phase.

Metallocene catalyzed poly-alpha-olefins (mPAO) suitable for the present invention are low molecular weight polymers (also referred to as oligomers) that constitute alpha-olefins having at least 6 carbon atoms to about 20 carbon atoms, and may be homopolymers or copolymers of two or more of these monomeric units, provided that the polymer composition will meet the following requirements for mPAO. Typical mPAOs suitable for use according to the present invention contain monomer units (i.e. monomers) containing at least 6, preferably at least 8, more preferably at least 10 carbon atoms and at most 20 carbon atoms, preferably 18, more preferably 16, and most preferably a maximum of 14 carbon atoms.

According to one variant, mPAOs are, without limitation, oligomers of one or more monomers, which are hexene, octene, decene, dodecene and tetradecene, including, in particular, co-oligomers that are obtained from mixtures of two or more of these monomers, moreover, data mixtures of monomers are often prepared by monomer preparation processes. These mPAOs obtained are commercially available. Mixtures of two or more mPAOs may also be used in accordance with the present invention. However, if the mPAO is a mixture of two or more mPAOs having different viscosities and/or viscosities, then the mixture must have viscosities and/or viscosities within the prescribed ranges. When using combinations or mixtures of mPAO, they can be mixed in any way before the reactor, in the reactor or after the reactor.

According to the present invention, the PAOs used are prepared in the presence of a metallocene catalyst and are mPAOs. Metallocene catalysts are compounds of group IV transition metals of the Periodic Table of Elements, such as titanium, zirconium, hafnium, etc., and have a coordinated structure containing a metal and ligands, representing

- 6 040086 which are compounds of one or two groups, including cyclopentadienyl, indenyl, fluorenyl or their derivatives. Metallocenes contain a single metal center, which provides improved control of branching and molecular weight distribution of the oligomers.

The metallocene components used to make suitable mPAOs can be simple metallocenes, substituted metallocenes, or bridged metallocene catalysts that are activated or promoted by, for example, methylalumoxane (MAO) or a non-coordinating anion such as K,K-tetrakis(perfluorophenyl)dimethylanilinium borate or another equivalent anion, optionally with co-activators, which are typically trialkylaluminum compounds. The corresponding polymerization method and processes are described in numerous patents, for example WO 02/14384.

The metallocene component may be applied to the carrier according to any method known in the art. If applied, the carrier used according to the present invention may be any organic or inorganic solid, in particular a porous carrier such as silica, talc, inorganic oxides, as well as resinous carrier materials such as polyolefin. . Preferably the carrier material is an inorganic oxide present in finely divided form.

The use of metallocene-catalyzed PAOs (mPAOs) in accordance with the present invention has several advantages over conventional PAOs. One advantage lies in the PAO structure itself. Essentially, while traditional PAOs are a random distribution of short and long side chains, mPAOs are a uniform comb-like structure that lacks short side chains. This mPAO structure plays an important role in the properties they exhibit. For example, mPAOs typically have a higher viscosity index than traditional PAOs, mineral oils, and PIBs. The high viscosity index provides better protection at high temperatures and improved fluidity at low temperatures. In addition, mPAOs generally exhibit lower pour points than PAOs, mineral oils, and PIBs, which is of interest for low temperature applications. The mPAO structure is also expected to provide an improved final product consistency than that obtained with PAO.

In accordance with the present invention, the rubber-modified monovinyl aromatic polymer contains from 0.1 to 3.4 wt.% mPAO based on the total weight of the rubber-modified monovinyl aromatic polymer, having a kinematic viscosity of at least 950 mm ² /s at 40°C when measured according to ISO 3104.

Surprisingly, it has been found that the addition of high viscosity mPAOs to the rubber-modified monovinyl aromatic polymer increases the ESCR of the composition, while lower viscosity mPAOs are less effective. In addition, it has been found that this increase in ESCR can be achieved at low concentrations of mPAO.

According to a preferred embodiment, mPAO is present in an amount of at least 0.3 wt.% of the total weight of the rubber-modified monovinyl aromatic polymer, preferably at least 0.4 wt.%, more preferably at least 0.8 wt.%, still more preferably at least 1.0 wt.%, and most preferably at least 1.1 wt.%.

According to another embodiment, mPAO is present in an amount of not more than 3.3 wt.% of the total weight of the rubber-modified monovinyl aromatic polymer, preferably not more than 3.2 wt.%, preferably not more than 3.0 wt.%, preferably not more than 2.8 wt.% preferably not more than 2.5 wt.%, more preferably not more than 2.0 wt.%, even more preferably not more than 1.8 wt.% and most preferably not more than 1.5 wt.%.

According to a preferred embodiment of the present invention, the kinematic viscosity of mPAO is at least 1000 mm ² /s at 40°C and preferably at least 1100 mm ² /s at 40°C when measured according to ISO 3104. Preferably, the kinematic viscosity of mPAO is at most 1800 ^mm2 /s at 40°C, preferably not more than 1500 ^mm2 /s at 40°C, and more preferably not more than 1400 ^mm2 /s at 40°C when measured according to ISO 3104.

According to another preferred embodiment, the kinematic viscosity of mPAO is at least 100 mm ² /s at 100°C, preferably at least 110 mm ² /s at 100°C, and/or the kinematic viscosity of mPAO is not more than 200 mm ² /s at 100°C and preferably not more than 190 mm ² /s at 100°C when measured according to ISO 3104.

According to a preferred embodiment of the present invention, mPAO has a viscosity index of at least 200 as determined according to ISO 2909.

The mPAOs of the present invention have a pour point of less than -20°C, preferably less than -25°C, more preferably less than -30°C, and most preferably less than -35°C, as determined according to ISO 3016.

Additional additives for the composition

The compositions of the present invention may further comprise one or more

- 7 040086 fillers and / or additives, provided that they do not adversely affect the desired combination of properties that could otherwise be obtained, or that they preferably improve one or more of the properties.

For example, plasticizers (preferably mineral oil and/or polyisobutene) are one type of additive that can improve the ESCR of HIPS or other rubber modified monovinyl aromatic polymers such as ABS. These materials are added in known quantities using conventional equipment and technology. Other exemplary fillers are talc, calcium carbonate, organoclay, glass fibers, marble dust, cement dust, feldspar, silica or glass, fumed silica, silicates, alumina, various phosphorus compounds, ammonium bromide, antimony(III) oxide , zinc oxide, zinc borate, barium sulfate, organosilicon compounds, aluminum silicate, calcium silicate, titanium oxides, glass microspheres, chalk, mica, clays, wollastonite, ammonium octamolybdate, thermally expandable compounds, expandable graphite, and mixtures of two or more of these materials. Fillers may carry or contain a variety of surface coating or impregnating agents such as silanes, fatty acids, and the like.

According to one embodiment, the composition contains a plasticizer, preferably mineral oil and/or polyisobutene. Preferably, the concentration of the plasticizer (i.e. the concentration of mineral oil and/or polyisobutene) is more than 0.1 wt.%, preferably at least 0.5 wt.%, more preferably at least 0.8 wt.%, preferably at least 1.0 wt.%, preferably at least 1.5 wt.% and most preferably at least 2.0 wt.% of the total weight of the composition. The concentration of the plasticizer (i.e. the concentration of mineral oil and/or polyisobutene), if used, is preferably no more than 6 wt.%, more preferably no more than 5 wt.%, even more preferably no more than 4 wt.% , even more preferably not more than 3.5 wt.%, and most preferably not more than 3.0 wt.% of the total weight of the composition.

Mineral oils have a typical kinematic viscosity at 40°C of 65 to 100 mm ² /s, preferably about 70 mm ² /s as determined according to ISO 3104. According to one embodiment, the mass ratio of plasticizer and mPAO in the composition is not more than 1 :1, preferably not more than 1:0.75.

In one embodiment, the weight ratio of plasticizer to mPAO in the composition is at most 1:50, preferably at most 1:10, more preferably at most 1:4, more preferably at most 1:0.75.

According to another embodiment, the weight ratio of plasticizer and mPAO in the composition is at least 1:0.1, preferably at least 1:0.2.

In addition, other additives are flame retardants such as halogenated organic compounds. The composition may also contain additives such as, for example, antioxidants (i.e., hindered phenols such as, for example, IRGANOX™ 1076), demolding aids, non-mineral oil processing aids (i.e., , other oils, organic acids such as stearic acid, salts of metals and organic acids), dyes or pigments, provided that they do not impair the desired physical or mechanical properties of the compositions according to the present invention.

Compositions according to the present invention may contain polymers other than monovinyl aromatic polymers and mPAO. Other exemplary polymers are, without limitation, ethylene polymer (i.e. low density polyethylene (LDPE), ultra low density polyethylene (ULDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE ), uniformly branched linear ethylene polymer, substantially linear ethylene polymer, modified grafted ethylene polymers, ethylene-vinyl acetate interpolymer, ethylene-acrylic acid interpolymer, ethylene-ethyl acetate interpolymer, ethylene-methacrylic acid interpolymer, ethylene-methacrylic acid ionomer, etc. ), conventional polypropylene (i.e., polypropylene homopolymer, polypropylene copolymer, polypropylene random block interpolymer, etc.), polyether block copolymer (i.e., PEBAX), polyphenylene ether, polyester copolymer, polyester/polyester block polymer ( i.e. HYTEL), an interpolymer of ethylene and carbon monoxide (t .e. ethylene carbon monoxide copolymer or ECO), ethylene acrylic acid carbon monoxide terpolymer (EAACO), ethylene methacrylic acid carbon monoxide terpolymer (EMAACO), ethylene vinyl acetate carbon monoxide terpolymer (EVACO), and styrene carbon monoxide copolymer ( SCO)), polyethylene terephthalate (PET), chlorinated polyethylene, styrene-butadiene-styrene (SBS) interpolymer, styrene-ethylene-butadiene-styrene (SEBS) interpolymer, and similar compounds and mixtures of two or more of the other polymers mentioned. Polyolefins, which may contain one or more other polymers, are high molecular weight and low molecular weight polyolefins, as well as saturated and unsaturated polyolefins.

If the composition contains one or more other polymers, then the other polymers are generally

- 8 040086 are present in an amount of not more than 20 wt.% of the total weight of the composition, preferably not more than 15 wt.%, more preferably not more than 10 wt.%, more preferably not more than 5 wt.%, and most preferably not more than 2 wt.% of the total weight of the composition.

The method of obtaining the composition

The invention provides a method for preparing a composition containing a rubber-modified monovinyl aromatic polymer, the above method comprising the step of polymerizing a reaction mixture of a monovinyl aromatic monomer, one or more rubbers, and one or more poly-alpha-olefins (mPAO) obtained in the presence of a metallocene catalyst, and wherein one or more than mPAO are present in an amount ranging from 0.1 to 3.4 wt.% of the total mass of the mixture.

You can combine or mix mPAO with monovinyl aromatic polymer, carrying out any method of combining or mixing before the reactor, in the reactor or after the reactor.

According to one embodiment of the present invention, the mPAO component(s) as defined above are introduced in liquid form into the polymerization process of the monovinyl aromatic polymer, preferably into a monomer solution, into an injection solution containing dissolved rubber, or by any other means during or before initiation of the polymerization reaction. Preferably, mPAO is added prior to initiation of the polymerization reaction.

Thus, according to one embodiment, the method according to the present invention includes the following steps:

a) introducing a reaction mixture containing at least one monovinyl aromatic monomer, at least one rubber, at least one mPAO having a kinematic viscosity of at least 950 mm ² /s at 40°C and not more than 2000 mm ² /s at 40° C. as measured according to ISO 3104, and an optional free radical initiator for polymerization into a phase inversion reactor and polymerization of the reaction mixture in the phase inversion reactor to a level above the inversion point of the reaction mixture to obtain a first polymerization mixture containing at least rubber and mPAO ;

b) introducing the first polymerization mixture into a polymerization reactor to form a second polymerization mixture;

c) optional introduction of the second polymerization mixture into at least one subsequent reactor for post-inversion polymerization of the third polymerization mixture, in addition, the reaction mixture contains at least one monovinyl aromatic monomer, at least one rubber and at least one mPAO in effective proportions to obtain a rubber-modified monovinyl aromatic polymer containing:

wt.% or more of the monovinyl aromatic polymer matrix based on the total weight of the rubber-modified monovinyl aromatic polymer, from 2 to 12 wt.% of at least one rubber based on the total weight of the rubber-modified monovinyl aromatic polymer, and from 0.1 to 3.4 wt.% obtained in the presence of a metallocene catalyst for poly-alpha-olefins (mPAO) based on the total weight of the rubber-modified monovinyl aromatic polymer.

According to one variant, step (a) is carried out in two or more steps, including:

a1) introducing a reaction mixture containing at least one monovinyl aromatic monomer, at least one rubber, at least one mPAO and an optional free radical polymerization initiator into a pre-inversion reactor and polymerizing the reaction mixture in the reactor to a level below the inversion point of the reaction mixture to obtain prepolymerization mixture;

a2) introducing the prepolymerization mixture into the phase inversion reactor and polymerizing the prepolymerization mixture to a level above the inversion point of the prepolymerization mixture to obtain a first polymerization mixture.

According to one embodiment, the reaction mixture is prepared by dissolving separately at least one rubber to obtain a stock solution containing dissolved rubber and at least one mPAO to obtain a stock solution containing dissolved mPAO, and adding a stock solution containing at least one dissolved mPAO , to the initial solution containing dissolved rubber, and optionally adding a free radical polymerization initiator to obtain a reaction mixture.

In another embodiment, the reaction mixture is prepared by dissolving at least one rubber to form a stock solution containing the dissolved rubber, adding at least one mPAO to the stock solution containing the dissolved rubber, and dissolving at least one mPAO in the presence of a stock solution containing the dissolved rubber. rubber, and optionally adding a free radical polymerization initiator to form a reaction mixture.

According to the following variant, the reaction mixture is prepared by dissolving at least one mPAO to obtain a stock solution containing dissolved mPAO, adding at least one rubber to the stock solution containing dissolved mPAO, and dissolving at least one

- 9 040086 rubber in the presence of an initial solution containing dissolved mPAO, and optionally adding a free radical polymerization initiator to obtain a reaction mixture.

In another embodiment, a reaction mixture is prepared by simultaneously dissolving at least one rubber and at least mPAO to form a solution containing dissolved rubber and mPAO, and optionally adding a free radical initiator to form a reaction mixture.

According to one variant, the reaction mixture additionally contains at least one additive, which is chosen as a plasticizer, a flame retardant material, a filler and a polymer that is not a monovinyl aromatic polymer, as well as at least one mPAO. Preferably, the reaction mixture contains at least one plasticizer additive, preferably mineral oil and/or polyisobutene. These additives are dissolved separately or together with at least one rubber and/or at least one mPAO.

In one embodiment, the first reaction mixture contains diluents such as ethylbenzene, toluene, xylene, or a combination thereof. In the first reaction mixture, the rubber is dissolved in one or more monovinyl aromatic monomers, preferably styrene.

Preferably, prior to the post-inversion polymerization, the polymerization reaction takes place in two or more reactors connected in series.

The phenomenon of phase inversion is well known to the person skilled in the art and is further explained by the example of monovinyl aromatic monomer, which is styrene. The first reaction mixture is polymerized under pre-inversion conditions, in which the continuous phase is a solution containing rubber and styrene, and the dispersed phase contains styrene and polystyrene. As the reaction of converting styrene to polystyrene proceeds and the amount of polystyrene increases, a phase inversion occurs, after which the mixture of polystyrene and styrene forms a continuous phase in which rubber particles are dispersed. This polymerization reaction can be carried out in one reactor in step (a) or in at least two reactors in steps (a1) and (a2) when at least two steps are carried out.

The control of the rubber particle size is carried out by adjusting the process parameters (solid content, peroxide, temperature, diluent content, etc.) mainly in this particular reactor, but also in the upstream reactor, if present. The regulation of parameters is well known to the person skilled in the art.

Typical free radical polymerization initiators are azo compounds and peroxides. Examples of peroxides are t-butyl peroxybenzoate, t-butyl peroxyacetate, dit-butyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, 1,1-bis-t-butylperoxycyclohexane, 1,1-bis-t-butylperoxy-3,3,5-trimethylcyclohexane and dicumyl peroxide.

The at least one pre-inversion reactor and the phase-inversion reactor can be individually selected from a vertically positioned positive displacement reactor (PFR), a horizontally positioned positive displacement reactor (PFR) and a continuously stirred tank reactor (CSTR). According to one variant, at least one of the pre-inversion reactor and the phase-inversion reactor are equipped with agitators.

In one embodiment, the at least one pre-inversion reactor is operated at a temperature of at least 110°C, preferably 115 to 150°C, more preferably 120 to 140°C and most preferably 125 to 135°C.

Preferably in step (b) the first polymerization mixture is introduced into a polymerization reactor which is a plug flow reactor (PFR).

In one embodiment, the rubber-modified monovinyl aromatic polymer exiting the final polymerization or post-polymerization reactor is sent to a devolatization unit to remove volatiles prior to the extrusion step. The devolatization unit may include a preheater.

Thus, preferably, the method further comprises the following steps:

d) a devolatization step comprising introducing the resulting polymerization mixture into one or more devolatizers to remove volatiles and crosslink the rubber, and

e) an optional extrusion step.

If the composition contains additives, such as mineral oil, they can be introduced into the reaction mixture or at any point in the polymerization process up to and including the final polymerization reactor, as is well known to a person skilled in the art.

The method includes adjusting the size of the rubber particles, said control comprising determining the solids content of the phase inversion reactor according to methods well known in the art.

Alternatively, the mPAO component may be incorporated into the monovinyl aromatic polymer resin by any of the conventional well known blending techniques that are used.

- 10 040086 are used for other additives.

Products

The articles of the present invention (obtained from the composition of the present invention) are selected from films, fibers, sheet structures, molded objects (such as parts of appliances and automobiles), hoses, gaskets for refrigerators and other uses, clothing and footwear components, seals, and the like. e. Articles are made by any manufacturing and/or shaping method such as extrusion, casting, injection molding, blow molding, thermoforming, etc.

The present invention may be further illustrated by means of the following examples, although it should be understood that these examples are provided for purposes of illustration only and are not intended to limit the scope of the present invention unless specifically stated otherwise.

Examples

Research methods.

Kinematic viscosity at 100°C (mm ² /s) was determined according to ISO 3104.

Kinematic viscosity at 40°C (mm ² /s) was determined according to ISO 3104.

It should be noted that the ISO 3104 standard corresponds to the ASTM D445-03 standard.

The viscosity index was determined according to ISO 2909.

Cleveland open cup flash point (COC) (°C) was determined according to ISO 2592.

Pour point (°C) was determined according to ISO 3016.

The melt flow rate of the composition was measured according to ISO 1133. For polystyrene, the melt flow rate (MI5) was measured according to ISO 1133 under H conditions at 200° C. under a load of 5 kg.

Molecular mass. Molecular weight can be measured using Gel Permeation Chromatography. Various solvents can be used, with a typical solvent being tetrahydrofuran. Polystyrene standards can be used for calibration.

Molecular weight averages used to establish relationships between molecular weight and properties are number average (M _n ), weight average (M _w ), and z average (M _z ) molecular weights. These average values are determined by the following expressions using the calculated Mi values:

М„ - ±--= —ί---- —X—

Σ$ι Σ^'M, Xh/M,

Σ^^ί Σ^ί = ---- ---Σ^Ι ^Μ Ι Σ ^Μ ί f V ί

Σ^ m = X____ j____ X__ yes _s Y

Σ^ι Σ^Μ Σ^

Ύ τ >

Here, Ni and Wi are, respectively, the number and mass of molecules having the molecular weight Mi. As a rule, the values of M _w , M _z and M _n are determined by gel permeation chromatography using polystyrene standards with narrow molecular weight ranges for calibration.

D50(v) (μm) - the volume median diameter of the rubber particles was measured by laser light scattering using a HORIBA 920 particle size analyzer from Horiba Scientific. The samples were suspended in methyl ethyl ketone at a concentration of approximately 1 wt.%. Particle size was confirmed by scanning electron microscopy (SEM).

Notched Izod impact strength was measured at 23° C. according to ISO 180.

Vicat softening point B50 was measured according to ISO 306 at a heating rate of 50° C./h under a load of 50 N.

The Dow bar test was used to determine the environmental stress resistance of test specimens molded according to ISO 527 1A that were subjected to a fixed bending strain of 1.36% in the presence of commercial olive oil (Puget). The result is the ratio of the elongation at break of the stressed specimen to its original elongation at break (eg, normalized elongation at break). Typical stress duration was 1, 2, 3, 4 and 7 days.

Three point bend test (3PBT). Test specimens equivalent to the central part of the test specimen according to ISO 3167 1A were subjected to constant stress in the presence of isopropyl palmitate in a three-point bending system. The test was repeated at different

- 11 040086 voltages. The result is the break time.

The amount of PBu in the final resin was determined by 1H NMR.

A weighed portion of 100 g of the sample was placed in a small vial. 1 ml of CDCl3 and 1 drop of trimethylsilane (TMS) were added to the vial. The sample was shaken at room temperature (approximately 22°C) until the solution became homogeneous. Thereafter, the homogeneous solution was placed in a 5 mm tube for NMR samples.

The standard 1H NMR spectrum was recorded using 32 scans and a 90° pulse on a Bruker instrument operating at 400 MHz.

Temporal resolution: 32k.

Sweep area: 15 ppm centered on 5.5 ppm

Delay between scans: 10 s.

Rotation speed: 20 Hz.

Temperature: 25°C.

Before performing the Fourier transform, it is possible to use exponential multiplication with a small coefficient of spectral line broadening (LB = 0.3). The spectrum was phased and a linear background correction was applied in the range from 11 to -1 ppm.

The TMS signal corresponded to 0 ppm.

The signals were integrated and normalized areas for each compound were calculated from the integrated areas. The composition was normalized to 100%.

The content of PBu in the resin was determined as follows:

PBu (wt%) = 100 54 PBi area/(104-PS area + 7 (aliphatic area -

3 area PS - 4 area PBu) + 54 area PBu)

Here area PBu = (area from 6 ppm to 4 ppm)/2 Area PS = (area from 9 ppm to 6 ppm)/5 Aliphatic area = area from 4 ppm . up to 0.2 ppm

Amount of mineral oil, mPAO, PIB: The content of mineral oil (MO), mPAO and PIB (wt%) in the resin can be determined as follows:

[MO]f=([MO ]i-100)/(SC)

[mPAO]f = ([mPAO]i 100)/(SC)

[PIB]f= ([PIB]il00)/(SC) where

[X]i (wt%) is the amount of X formulated (X is MO, mPAO, or PIB),

[X]f (wt%) is the X content in the final resin (X is MO, mPAO or PIB),

SC (wt%) is the final solids content and is calculated as follows:

SC = ([PBu]i/[PBu]f) 100) where

[PBu]i (wt.%) is the amount of PBu introduced into the formulation, [PBu]f (wt.%) is the content of PBu in the final resin, determined by NMR.

The present invention is illustrated by the following non-limiting examples.

Examples

In table. 1 shows a comparison of mPAO properties and PIB properties. mPAO1, mPAO2 and mPAO3 correspond to the Durasyn® 180R, Durasyn® 180I and Durasyn® 174I products sold by INEOS Oligomers. They are high viscosity poly-alpha-olefins, fully synthesized and hydrogenated hydrocarbon base fluids from the original linear C10-alpha-olefin. PIB is the PIB H100 product from Ineos.

mPAO1 and mPAO3 are comparative mPAOs while mPAO2 are mPAOs according to the present invention.

- 12 040086

Table 1. Properties of mPAO and PIB

mPAOl (Durasyn® 180R) mPAO2 (Durasyn® 1801) traoz (Durasyn® 1741) PIB (Hl00) Kinematic viscosity at 100°С, mm ² /s 98 35 50 220 Kinematic viscosity at 40°С, mm ² /s 927 1250 411 Viscosity index 197 216 186 - Flash point COC (°C) 290 304 286 170 M _w (Yes) 2300 2700 1720 - Pour point (°C) -40 -37 -47 -

The polymerization reactions were carried out in a laboratory reactor using the following formulation: 6.2 wt.% PVi, 1.1 wt.% mineral oil, 0 or 1 wt.% PIB. After obtaining 3 kg of each comparative resin (CO and C1), respectively, 0.4 wt.% and 1.2 wt.% mPAOl, mPAO2 or tPAOS was added to the dissolution section instead of PIB. The next polymerization was carried out by replacing PIB with 2.5 wt% tPAO2. the rest of the polymerization conditions remained unchanged. In table. 2 details the polymerization conditions and formulation composition.

Table 2. Polymerization conditions and formulation composition

SO Without PIB Without mPAO C1 PIB H100 С2 mPAOl NW mPAOl C4 TRAO2 C5 TRAO2 C6 TRAO2 C7 traoz C8 traoz Styrene (wt%) 82.3 81.5 81.5 81.5 81.5 82.3 80 81.5 82.3 Ethylbenzene (wt%) 10 10 10 10 10 10 10 10 10 Rubber (wt%) 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 PIB or mPAO (wt%) 0 1.2 1.2 0.4 1.2 0.4 2.5 1.2 0.4 Mineral oil (wt%) 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 Normal dodecylmercaptan (NDM) (ppm) 250 250 250 250 250 250 250 250 250 Peroxide (ppm) 225 225 225 225 225 225 225 225 225

Luperox 331 peroxide was used in all experiments. Buna CB550T rubber from Lanxess was used. Buna CB55OT is a low cis, medium viscosity butadiene rubber prepared with a lithium catalyst, for which the viscosity of a 5.43% solution in toluene is 163 mPa-s when determined according to ISO 3105.

Fina Vestan mineral oil used (kinematic viscosity at 40°C was 68 mm ² /s according to ISO3104).

Compositions C4, C5 and C6 are compositions according to the present invention. Other compositions are comparative compositions.

In table. 3 shows the properties of the compositions.

Table 3. Composition properties

SO Without PIB Without mPAO C1 PIB nuo C2 mPAOl NW mPAOl C4 TRAO2 C5 TRAO2 C6 TRAO2 C7 traoz C8 traoz Content RVi (wt%) 8 7.9 7.1 7 7.4 8 7.9 7.3 7.6 Solids content 77.5 78.5 87.3 88.6 83.8 77.5 78.5 84.9 81.6

- 13 040086

(wt%) Mineral oil content (wt%) 1.4 1.4 1.3 1.2 1.3 1.4 1.4 1.3 1.3 PIB content (wt%) 0 1.5 0 0 0 0 0 0 0 mPAO content (wt%) 0 0 1.4 0.5 1.4 0.5 3.2 1.4 0.5 MI5 (g/10 min) 3.5 4.6 4.7 4.7 4.5 4.1 3.1 4.1 4.1 M _w (kDa) 168 160 164 156 156 155 161 153 154 MP (kDa) 71 76 71 68 66 62 61 61 61 M ₂ (kDa) 289 268 277 269 268 275 281 271 273 Mw _/ Mn 2.4 2.1 2.3 2.3 2.4 2.5 2.6 2.5 2.5 D50(v) (µm) 3.6 5.1 4.4 5.5 6.2 6.0 3.9 5.4 6.0 V notched Izod impact strength at 23°C (J/m ² ) No data 12.3 I,4 11.0 9.9 I,7 No data P,4 10.9 Vicat softening point B50 (°C) 90 88.6 89.5 90.8 89.9 90.3 87.6 89.6 90.3

The stress crack resistance of the products was analyzed in the Dow bar test and in the three point bend test. The results are presented in detail in table. 4 and in FIG. 1.

The Dow bar test is an improved measure of elongation at break for HIPS samples containing 3.3 wt.%, 1.6 wt.% and 0.5 wt.% mPAO2 after 7 days. The lower viscosity mPAO1 and mPAO3 do not improve stretch properties compared to PIB after 7 days. This result was unexpected since an improvement in tensile properties was observed at low mPAO concentrations of only 0.5 wt%.

The improved stress crack resistance of a HIPS sample containing 1.6 wt% high viscosity mPAO2 (Durasyn 180I) was confirmed by a three-point bend test (to assess stress cracking) as shown in the drawing.

Table 4. Dow bar test results for injection molded bars.

Elongation at break (%) Time contact SO Without PIB Without mPAO C1 PIB H100 С2 mPAOl sz mPAOl C4 TRAO2 C5 TRAO2 C6 TRAO2 C7 traoz C8 traoz Pure Sample 35.2 42.7 36.0 34.7 36.9 42.5 38.5 36.6 35.3 Sample with cracking agent 15 minutes 37.8 44.4 37.8 33.2 38.0 38.1 36.9 39.3 34.8 1 day 30.4 36.6 32.0 31.0 40.8 31.8 39.0 38.7 30.2 2 days 23.5 23.3 11.7 10.8 28.5 14.9 43.6 11.8 27.2 3 nights 6.7 13.2 9.7 9.3 AND 2 12.8 39.7 5.5 4.6 4 nights 5.4 13.3 5.9 9.5 6.9 10.0 37.5 5.8 5.3 7 nights 5.1 3.6 3.2 2.9 7.1 6.8 12.6 3.0 3.2

CLAIM

Claims (16)

1. A rubber-modified monovinyl aromatic polymer containing 70 wt.% or more of a monovinyl aromatic polymer matrix based on the total weight of the rubber-modified monovinyl aromatic polymer, from 2 to 12 wt.% of at least one rubber based on the total weight of the rubber-modified monovinyl aromatic polymer, and from 0.1 to 3.4 wt.% obtained in the presence of a metallocene catalyst for poly-alpha-olefins (mPAO) based on the total weight of the rubber-modified monovinyl aromatic polymer, wherein the mPAOs have a kinematic viscosity of at least 950 mm ² /s at 40°C and not more than 2000 mm ² /s at 40° C when measured according to ISO 3104. 2. The rubber-modified monovinyl aromatic polymer according to claim 1, characterized in that mPAO is present in an amount of at least 0.3 wt.% of the total weight of the modification. - 14 040086 rubberized monovinyl aromatic polymer, preferably at least 0.4 wt.%; and mPAO is present in an amount of not more than 3.0% by weight based on the total weight of the rubber-modified monovinyl aromatic polymer, preferably not more than 2.8% by weight, more preferably not more than 1.8% by weight. 3. The rubber-modified monovinyl aromatic polymer according to claim 1 or 2, characterized in that the kinematic viscosity of mPAO is at least 1000 mm ² /s at 40°C and preferably at least 1100 mm ² /s at 40°C when measured according to ISO 3104 standard; and the kinematic viscosity of mPAO is not more than 1800 mm ² /s at 40°C, preferably not more than 1500 mm ² /s at 40°C, and more preferably not more than 1400 mm ² /s at 40°C when measured according to the standard ISO 3104. 4. The rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 3, characterized in that the kinematic viscosity of mPAO is at least 100 mm ² /s at 100°C, preferably at least 110 mm ² /s at 100°C and /or kinematic viscosity mPAO is not more than 200 mm ² /s at 100°C and preferably not more than 190 mm ² /s at 100°C when measured according to ISO 3104. 5. The rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 4, characterized in that the mPAO viscosity index is at least 200 when determined according to ISO 2909. 6. A rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 5, characterized in that mPAO has a pour point of less than -30°C and most preferably less than -35°C when determined according to ISO 3016. 7. The rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 6, characterized in that it additionally contains a plasticizer in an amount ranging from 0.1 to 6 wt.% of the weight of the rubber-modified monovinyl aromatic polymer, and the plasticizer is preferably mineral oil and/or polyisobutene. 8. The rubber-modified monovinyl aromatic polymer according to claim 7, wherein the weight ratio of plasticizer to mPAO in the rubber-modified monovinyl aromatic polymer is not more than 1:50, preferably not more than 1:10, more preferably not more than 1:4. 9. A rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 8, characterized in that it is rubber-modified polystyrene (HIPS) or rubber-modified poly(styrene-acrylonitrile) (ABS). 10. A rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 9, characterized in that the rubber is selected from the group consisting of polybutadiene, polyisoprene, copolymers of butadiene and/or isoprene with styrene, and natural rubber. 11. A rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 10, characterized in that the weight average molecular weight (MW) of the monovinyl aromatic polymer matrix is at least 130,000 g/mol, preferably at least 140,000 g/mol, as determined by gel permeation chromatography. , and more preferably at least 150,000 g/mol, and/or the molecular weight distribution of the monovinyl aromatic polymer matrix is at least 1.8, preferably at least 2.1. 12. A method for producing a rubber-modified monovinyl aromatic polymer according to any one of claims 1 to 11, comprising the step of polymerizing a reaction mixture of a monovinyl aromatic monomer, one or more rubbers, and one or more poly-alpha-olefins (mPAO) obtained in the presence of a metallocene catalyst, wherein one or more than mPAO are present in an amount ranging from 0.1 to 3.4 wt.% of the total mass of the mixture. 13. The method according to claim 12, characterized in that the reaction mixture is obtained by: a) introducing a reaction mixture containing at least one monovinyl aromatic monomer, at least one rubber, at least one mPAO having a kinematic viscosity of at least 950 mm ² /s at 40°C and not more than 2000 mm ² /s at 40° C. as measured according to ISO 3104, and an optional free radical polymerization initiator in the phase inversion reactor and polymerization of the reaction mixture in the phase inversion reactor to a level above the inversion point of the reaction mixture to obtain a first polymerization mixture containing at least rubber and mPAO ; b) introducing the first polymerization mixture into a polymerization reactor to form a second polymerization mixture; c) optionally introducing the second polymerization mixture into at least one subsequent reactor for post-inversion polymerization of the third polymerization mixture. 14. The method according to claim 13, characterized in that stage (a) is carried out in two or more stages, including: a1) introducing a reaction mixture containing at least one monovinyl aromatic monomer, at least one rubber, at least one mPAO, and an optional self-initiator - 15 040086 bodine-radical polymerization, in a pre-inversion reactor and polymerization of the reaction mixture in the reactor to a level below the inversion point of the reaction mixture to obtain a pre-polymerization mixture; a2) introducing the prepolymerization mixture into a phase inversion reactor and polymerizing the prepolymerization mixture to a level above the inversion point of the prepolymerization mixture to obtain a first polymerization mixture. 15. An article comprising the rubber-modified monovinyl aromatic polymer of claim 111, wherein the article is selected from films, fibers, sheet structures, molded objects, automotive parts, hoses, refrigerator liners and other liners, apparel and footwear components, and seals. 16. A method for producing an article according to claim 15, which includes the step of extruding and/or thermoforming the article or the step of injection molding the article using the rubber-modified monovinyl aromatic polymer according to claims 1 to 11.