HK1140785B - Coloured composition with increased stress cracking resistance - Google Patents

Description

Coloring composition with improved stress cracking resistance

Technical Field

The present invention relates to a coloring composition having improved stress cracking resistance and use thereof.

Background

Polymethyl methacrylate (PMMA) compositions have been used for a long time in the automotive sector, in particular as taillight covers and instrument covers. In recent years, such materials have also been increasingly used for covering pigmented moldings. Applications here are, in particular, spoilers, pillar claddings, window guides, exterior mirrors and exterior mirror bases.

These PMMA compositions are usually processed by extrusion, coextrusion, injection molding or multicomponent injection molding to obtain molded bodies for outdoor areas. Thus, in these applications, at least the uppermost layer is composed of PMMA. Because of their weather stability and surface hardness, PMMA protects the underlying substrate.

Since the shaped bodies are often dark (the PMMA layer itself or the underlying layers), they are heated to a great extent in sunlight. High heat distortion resistance is therefore a requirement for PMMA compositions, so that the molded bodies pass the appropriate weathering test and do not soften.

In addition, the shaped bodies must have a high stress cracking resistance and a high chemical resistance, since these applications are frequently in contact with cleaning agents, gasoline and other corrosive agents.

In addition, the known properties of PMMA compositions or PMMA moldings, such as processability and mechanical properties, must be retained.

EP 0508173B1 describes the use of polymer blends comprising 55% to 98% by weight of PMMA, 2% to 45% by weight of styrene-acrylonitrile copolymer (SAN) and optionally further processing aids for the preparation of various shaped parts. The PMMA contains, as described, at least 80 wt.% Methyl Methacrylate (MMA) units. In the examples, stress crack formation was observed after 2.1min to 5.5 min. However, this value is not comparable to the results of the present invention according to the ESCR test. The vicat softening temperature of an exemplary PMMA-SAN polymer blend is 106 ℃.

Similarly, EP 0627461B1 discloses weatherable blends comprising 49 wt% to 99 wt% PMMA and 0.95 wt% to 50 wt% SAN and 0.05 wt% to 1 wt% of certain stabilizing agent packages (pakets). The PMMA also contains at least 80% by weight of MMA units. In the examples, stress crack formation was observed after 680s-750 s. However, this value is not comparable to the results of the present invention according to the ESCR test. No improvement in heat distortion resistance is described.

JP 03-217446a2 relates to blends formed from copolymers of aromatic vinyl monomers with (meth) acrylic acid, PMMA and SAN. The blends have a relatively high heat distortion resistance value (114 ℃). However, the transmittance of the molded article was only 84%.

JP 02-272050A2 describes blends having good heat distortion resistance and impact strength comprising

a) 40-90 wt.% MMA, 5-20 wt.% maleic anhydride, 5-40 wt.% styrene and 1-15 wt.% acrylic acid C_1-4A copolymer of an alkyl ester of a carboxylic acid,

b) copolymers of acrylonitrile with aromatic vinyl compounds or MMA-acrylic acid C_1-4An alkyl ester copolymer comprising a copolymer of an alkyl ester,

c) an impact modifier composed of a rubber grafted with acrylonitrile and an aromatic vinyl compound.

The refractive index difference between the mixture of components a) and b) and component c) should be at most 0.005. Nevertheless, such compositions exhibit a strong dependence of the optical properties, in particular the transparency and/or the color impression, on the temperature.

Application WO 2005/047392A1 discloses polymer mixtures comprising the following components:

a) low molecular weight (meth) acrylate (co) polymers characterized by a solution viscosity in chloroform at 25 ℃ lower than or equal to 55ml/g (ISO 1628-part 6),

b) impact modifiers based on crosslinked poly (meth) acrylates,

c) higher molecular weight (meth) acrylate (co) polymers characterized by a solution viscosity in chloroform at 25 ℃ (ISO 1628-part 6) such as/or greater than or equal to 65ml/g

d) (meth) acrylate (co) polymers other than a) characterized by a solution viscosity in chloroform at 25 ℃ of 50 to 55ml/g (ISO 1628-part 6),

where the components a), b), c) and/or d) can each themselves be understood as meaning individual polymers or mixtures of polymers, where a), b), c) and/or d) add up to 100% by weight, where the polymer mixtures can also contain the customary additives, auxiliaries and/or fillers. When the surface is wetted with isopropanol, the test pieces prepared from the polymer mixture are said to exhibit a time to failure of greater than 1800s at a constant peripheral fiber elongation of 0.39% and a time to failure of greater than 700s at a constant peripheral fiber elongation of 0.50%. However, a strong dependence of the optical properties, in particular the transparency and/or the color impression, on the temperature can likewise be observed. In addition, improved stress cracking resistance and better processability are particularly desirable.

Disclosure of Invention

Objects and solutions

The object on which the invention is based is therefore to indicate the possibility of improving the stress cracking resistance of pigmented compositions and shaped bodies. At the same time, the highest possible heat distortion resistance and the best possible optical properties should be achieved. In particular, as little temperature dependence as possible of the appearance of the compositions and shaped bodies is desirable. In addition, as good mechanical properties as possible, as good processability as possible and as high long-term stability and weathering resistance as possible should be achieved. It is also intended to indicate a particularly convenient process for the preparation of the novel compositions and shaped bodies and particularly advantageous possible uses.

This object, as well as further objects which may be derived necessarily from the above discussion or directly, are achieved by a colouring composition having all the features of claim 1 of the present invention. The dependent claims dependent on this claim describe particularly advantageous improvements of the composition and the other claims relate to particularly advantageous uses of the composition.

By providing a coloring composition comprising the following components, a coloring composition which is outstandingly suitable for producing shaped bodies having improved stress cracking resistance, in each case based on the total weight thereof, is successfully provided in a manner which cannot be predicted without difficulty:

A) from 50.0% to 99.5% by weight of at least one (meth) acrylate (co) polymer, and

B) from 0.5% to 50.0% by weight of at least one copolymer obtainable by polymerizing a monomer mixture comprising:

from 70% by weight to 92% by weight of vinylaromatic monomers, and

ii.8% to 30% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

iii 0% to 22% by weight of at least one further monomer,

wherein the composition exhibits a Δ Ε of less than 0.15 at 50 ℃, wherein Δ Ε is as defined below, and the composition contains at least one (meth) acrylate (co) polymer a) having a solution viscosity in chloroform at 25 ℃ (ISO 1628-part 6) of greater than 55 ml/g. The compositions described herein can be produced and processed in a comparatively simple manner, in particular at low energy expenditure, and also allow critical component geometries to be achieved.

At the same time, articles that can be prepared from the composition exhibit the following combination of advantageous properties:

they have very good optical properties, in particular a high color constancy, and show a comparatively small dependence of the appearance on temperature.

They have a very high resistance to thermal deformation.

They exhibit outstanding mechanical properties, in particular a high modulus of elasticity and a comparatively high Vicat softening temperature.

The long-term stability and weathering resistance of the shaped bodies are likewise outstanding.

Modes for carrying out the invention

(meth) acrylate (co) Polymer A)

The invention relates to moulding materials containing at least one (meth) acrylate (co) polymer A). The (meth) acrylate (co) polymer can be present here both as a single polymer and as a mixture of several polymers.

Properties of (meth) acrylate (co) Polymer A)

The (meth) acrylate (co) polymer is preferably selected in quantitative proportions and composition such that the test pieces prepared from the (meth) acrylate (co) polymer simultaneously have the following properties:

I. a tensile modulus (ISO 527) of at least 2600MPa, preferably at least 2750MPa, particularly preferably at least 2850MPa, in particular at least 3000MPa,

a Vicat softening temperature VET (ISO 306-B50) of at least 109 ℃, preferably at least 110 ℃, particularly preferably at least 112 ℃, in particular from 110 ℃ to 125 ℃,

III. at least 17kJ/m²Preferably at least 18kJ/m²Preferably at least 20kJ/m²Particularly preferably at least 25kJ/m²In particular at least 30kJ/m²Tensile strength (ISO 179-2D, flat (flatwise)),

at least 1.5cm³A/10 min, preferably at least 1.65cm³A/10 min, particularly preferably at least 2.0cm³10min, especially toLess than 3.0cm³Melt index MVR (ISO 1133, 230 ℃/3.8kg) at 10 min.

The usual additives, auxiliaries and/or fillers are advantageously selected such that the abovementioned property profile is as little or at most slightly adversely affected as possible.

Other properties

In addition, the (meth) acrylate (co) polymer is preferably present in a proportion and composition such that test pieces prepared from the (meth) acrylate (co) polymer also have at least some of the following properties:

inherent color

At least 50%, preferably at least 55%, of light transmission T to DIN 5033/7_D65。

Yellowness index

The yellowness index, which can be determined according to DIN 6167 (illuminant type D65, 10 ℃ for a layer thickness of 3 mm), should preferably be less than 20, preferably less than 17.

Stress cracking resistance (ESCR method)

Time to failure when wetting a surface with isopropanol at constant peripheral fiber elongation

●0.39％：＞1800s

●0.50％：＞700s

Surface gloss

R (60 °): greater than 48%, preferably greater than 50%

According to the invention, the composition is particularly characterized in that it contains at least one (meth) acrylate (co) polymer a) having a solution viscosity in chloroform at 25 ℃ (ISO 1628 part 6) of greater than 55ml/g, preferably greater than or equal to 65ml/g, in particular 68ml/g to 75 ml/g.

This may correspond to 16Molecular weight M of 0000g/mol_w(weight average) (M was measured by gel permeation chromatography using polymethyl methacrylate as a calibration standard)_w). The determination of the molecular weight Mw can be carried out, for example, by gel permeation chromatography or light scattering (cf., for example, Encyclopedia of Polymer Science and Engineering, 2 nd edition, volume 10, pages 1 and the following, J.Wiley, 1989, H.F. Mark et al).

In a first very particularly preferred variant of the invention, the (meth) acrylate (co) polymer a) is a copolymer of methyl methacrylate, styrene and maleic anhydride.

Suitable quantitative ratios may be, for example:

from 50% to 90% by weight, preferably from 70% to 80% by weight, of methyl methacrylate,

from 10% to 20% by weight, preferably from 12% to 18% by weight, of styrene, and

from 5% to 15% by weight, preferably from 8% to 12% by weight, of maleic anhydride.

The corresponding copolymers can be obtained in a manner known per se by free-radical polymerization. For example, EP-A264590 describes a process for preparing moulding compositions from monomer mixtures comprising methyl methacrylate, a vinylaromatic compound, maleic anhydride and optionally lower alkyl acrylates, in which the polymerization is carried out up to a conversion of 50% in the presence or absence of a non-polymerizable organic solvent and, starting from the conversion of at least 50%, the polymerization is continued up to a conversion of at least 80% in the temperature range from 75 ℃ to 150 ℃ in the presence of an organic solvent, and then the low molecular weight volatile constituents are evaporated off.

JP-A60-147417 describes a process for the preparation of polymethacrylate moulding compositions having high heat distortion resistance, in which a monomer mixture comprising methyl methacrylate, maleic anhydride and at least one vinylaromatic compound is fed to a polymerization reactor suitable for solution or bulk polymerization at temperatures of from 100 ℃ to 180 ℃ and polymerized. DE-OS 4440219 describes a further preparation process.

The proportion of (meth) acrylate (co) polymer a) is preferably at least 75% by weight, preferably at least 85% by weight, in particular at least 95% by weight, based on the total weight of all (meth) acrylate (co) polymers.

In a second very particularly preferred variant of the invention, the (meth) acrylate (co) polymers a) are composed of from 80% by weight to 100% by weight, particularly preferably from 90% by weight to 99.5% by weight, of methyl methacrylate units polymerized by free-radical means and optionally from 0% by weight to 20% by weight, preferably from 0.5% by weight to 10% by weight, of other comonomers which can be polymerized by free-radical means, for example C (meth) acrylate₁-C₄Homopolymers or copolymers of alkyl esters, in particular of methyl acrylate, ethyl acrylate or butyl acrylate.

Particularly preferred copolymers are those comprising from 95% to 99.5% by weight of methyl methacrylate and from 0.5% to 5% by weight, preferably from 1% to 4% by weight, of methyl acrylate.

Advantageously, the composition also contains at least one low molecular weight (meth) acrylate (co) polymer b) having a solution viscosity in chloroform at 25 ℃ (ISO 1628-part 6) of less than or equal to 55ml/g, preferably less than or equal to 50ml/g, in particular 45ml/g-55 ml/g.

This may correspond to a molecular weight M of 95000g/mol_w(weight average) (M was measured by gel permeation chromatography using polymethyl methacrylate as a calibration standard)_w). The determination of the molecular weight Mw can be carried out, for example, by gel permeation chromatography or light scattering (cf. for example, H.F. Mark et al Encyclopedia of Polymer Science and Engineering, 2 nd edition, volume 10, page 1 and later, J.Wiley, 1989).

The (meth) acrylate (co) polymer b) is preferably a copolymer of methyl methacrylate, styrene and maleic anhydride.

Suitable ratios of amounts may be, for example:

from 50% to 90% by weight, preferably from 70% to 80% by weight, of methyl methacrylate,

from 10% to 20% by weight, preferably from 12% to 18% by weight, of styrene, and

from 5% to 15% by weight, preferably from 8% to 12% by weight, of maleic anhydride.

Valuable indications concerning the preparation of such copolymers are obtainable in particular from EP-A264590, JP-A60-147417 and DE-OS 4440219.

The (meth) acrylate (co) polymer b) can be prepared, for example, as follows: 1.9g of tert-butyl perneodecanoate and 0.85g of tert-butyl peroxy-3, 5, 5-trimethylhexanoate as polymerization initiator and 19.6g of 2-mercaptoethanol as molecular weight regulator and 4.3g of palmitic acid are admixed to a monomer mixture comprising, for example, 6355g of methyl methacrylate, 1271g of styrene and 847g of maleic anhydride. The resulting mixture may be filled into a polymerization chamber and degassed, for example, for 10 minutes. Thereafter, the polymerization may be carried out in a water bath at 60 ℃ for, for example, 6 hours, and then at a water bath temperature of 55 ℃ for 30 hours. After about 30 hours, the polymerization mixture reached its maximum temperature at about 126 ℃. After removal of the polymerization chamber from the water bath, the polymerization product is accordingly tempered in the polymerization chamber for a further 7 hours, for example in an air oven at 117 ℃.

The (meth) acrylate (co) polymers a) and b) are advantageously present in a proportion of amounts which, based on the total weight of all (meth) acrylate (co) polymers, amounts to at least 75% by weight, preferably at least 90% by weight, in particular 100% by weight, in total.

(meth) acrylate (co) polymer a): from 25% by weight to 75% by weight, preferably from 40% by weight to 60% by weight, in particular from 45% by weight to 55% by weight,

(meth) acrylate (co) polymer b): 25% to 75% by weight, preferably 40% to 60% by weight, in particular 45% to 55% by weight.

Copolymer B)

In addition to the (meth) acrylate (co) polymer, the molding compositions according to the invention also contain at least one further copolymer (SAN copolymer) B) which is obtainable by polymerizing a monomer mixture comprising:

from 70% by weight to 92% by weight, preferably from 75% by weight to 82% by weight, in particular from 78% by weight to 81% by weight, of at least one vinylaromatic monomer, and

ii.8% to 30% by weight, preferably 18% to 25% by weight, in particular 19% to 22% by weight, of acrylonitrile or methacrylonitrile or mixtures thereof,

iii 0% to 22% by weight of at least one further monomer.

Particularly suitable vinylaromatic monomers are styrene, alpha-methylstyrene, tert-butylstyrene, monochlorostyrene and vinyltoluene, particularly preferably styrene and alpha-methylstyrene.

In addition, SAN copolymers having a molecular weight (weight average Mw) of from 60000g/mol to 300000g/mol, preferably from 100000g/mol to 200000g/mol, preferably prepared by the process described in GB-PS 1472195, have proven very particularly useful. The molecular weight is determined in a manner known per se, in particular by light scattering.

The amount of component B) is, according to the invention, from 0.5% to 50.0% by weight, preferably from 20.0% to 40.0% by weight, based on the total weight of the molding material.

The amounts of components a) and B) preferably amount to at least 75% by weight, preferably at least 90% by weight, in particular 100% by weight, based on the total weight of the composition.

The preparation of component B) is generally carried out by known polymerization methods, for example bulk, solution, emulsion or bead polymerization. These methods are described, for example, in Kunststoffhandbuch (plastics handbook), editors Vieweg and daumailler, volume V; polystyrol (polystyrene), Carl-Hanser-Verlag, Munich, 1969, pages 124 and beyond and described in GB-PS 1472195.

Additives, auxiliaries and/or fillers commonly used

The compositions according to the invention may also contain the usual additives, auxiliaries and/or fillers, such as heat stabilizers, UV absorbers, antioxidants, provided that these additives do not adversely affect the properties of the compositions according to the invention.

UV stabilizers and radical scavengers

The UV stabilizers which are optionally present are, for example, derivatives of benzophenone, the substituents, such as hydroxyl and/or alkoxy, being mostly in the 2-and/or 4-position. They include 2-hydroxy-4-n-octoxybenzophenone, 2, 4-dihydroxybenzophenone, 2, 2 ' -dihydroxy-4-methoxybenzophenone, 2, 2 ', 4, 4 ' -tetrahydroxybenzophenone, 2, 2 ' -dihydroxy-4, 4 ' -dimethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone. Furthermore, substituted benzotriazoles are very suitable as UV stabilizing additives and include, in particular, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- [ 2-hydroxy-3, 5-bis (. alpha.,. alpha. -dimethylbenzyl) phenyl ] benzotriazole, 2- (2-hydroxy-3, 5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3, 5-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3, 5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3, 5-di-tert-amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (, 2- (2-hydroxy-3-sec-butyl-5-tert-butylphenyl) benzotriazole and 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole.

Further UV stabilizers which may be used are ethyl 2-cyano-3, 3-diphenylacrylate, 2-ethoxy-2 '-ethyl-oxalanilide, 2-ethoxy-5-tert-butyl-2' -ethyl-oxalanilide and substituted phenyl benzoates.

The UV stabilizer may be present as a low molecular weight compound in the polymethacrylate material to be stabilized, as described above. However, the UV-absorbing groups may also be covalently bonded into the matrix polymer molecule after copolymerization with polymerizable UV-absorbing compounds, such as acryloyl-, methacryloyl-or allyl derivatives of benzophenone derivatives or benzotriazole derivatives.

The proportion of UV stabilizers (which here may also be a mixture of chemically different UV stabilizers) is generally from 0.01 to 1.0% by weight, in particular from 0.01 to 0.5% by weight, in particular from 0.02 to 0.2% by weight, based on the sum of all components of the polymethacrylate resin according to the invention.

As examples of free-radical scavengers/UV stabilizers, mention may be made here of sterically Hindered amines, known as HALS (Hindered Amine Light Stabilizer). They can be used for inhibiting the ageing process in coatings and plastics, in particular in polyolefin plastics (Kunststoffe (plastics), 74(1984)10, pp. 620 & 623; Farbe + Lack, 96 years, 9/1990, pp. 689 & 693). The tetramethylpiperidine group present in the HALS compound serves for the stabilization of the HALS compound. Such compounds may be unsubstituted or substituted with alkyl or acyl groups on the piperidine nitrogen. The sterically hindered amines do not absorb in the UV range. They trap the free radicals formed, which the UV absorbers are not able to exert.

Examples of HALS compounds which are stabilizing and which can also be used in mixtures are:

bis (2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate, 8-acetyl-3-dodecyl-7, 7, 9, 9-tetramethyl-1, 3, 8-triazaspiro (4, 5) decane-2, 5-dione, bis (2, 2, 6, 6-tetramethyl-4-piperidyl) succinate, poly- (N-. beta. -hydroxyethyl-2, 2, 6, 6-tetramethyl-4-hydroxypiperidine succinate) or bis- (N-methyl-2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate.

The free-radical scavengers/UV stabilizers are used in the compositions according to the invention in amounts of from 0.01 to 1.5% by weight, in particular from 0.02 to 1.0% by weight, especially from 0.02 to 0.5% by weight, based on the sum of all components.

Lubricants or mold release agents

Lubricants or mold release agents are particularly important for injection molding processes, which can reduce or completely prevent possible adhesion of the molding compound to the injection mold.

As auxiliaries, lubricants may therefore be present, selected, for example, from the group containing less than C₂₀Preferably C₁₆-C₁₈Saturated fatty acids containing less than C₂₀Preferably C₁₆-C₁₈Saturated aliphatic alcohols of carbon atoms. Preferably there is a small quantitative ratio: up to 0.25% by weight, for example from 0.05 to 0.2% by weight, based on the molding material.

For example, stearic acid, palmitic acid, technical mixtures of stearic acid and palmitic acid are suitable. Further suitable are, for example, n-hexadecanol, n-octadecanol, and also technical mixtures of n-hexadecanol and n-octadecanol.

Stearyl alcohol is a particularly preferred lubricant or mold release agent.

Other additives, auxiliaries and/or fillers

In the context of the present invention, component c₁)、c₂)、c₃) And/or c₄) The addition of (2) has also proven to be very particularly useful.

Component c₁) Refers to triarylphosphites of the general formula (I)

Wherein R is¹And R²Represents C₁-C₁₂Alkyl radicals, such as the methyl, ethyl, propyl, 1-methylethyl, n-butyl, 1-methylpropyl, methyl, ethyl, propyl, isopropyl,2-methylpropyl, 1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1, 2-dimethylpropyl, 1-dimethylpropyl, 2, 2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1, 2-dimethylbutyl, 1, 3-dimethylbutyl, 2, 3-dimethylbutyl, 1-dimethylbutyl, 2, 2-dimethylbutyl, 3-dimethylbutyl, 1, 2-trimethylpropyl, 1, 2, 2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, 1-ethylbutyl, 2-methylpropyl, N-heptyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 1-ethylpentyl, 2-ethylpentyl, 1-propylbutyl, octyl, nonyl, decyl, undecyl and dodecyl, preferably C branched in the 1-position (. alpha.)₃-C₁₂Alkyl, especially C₃-C₇Alkyl radicals, such as the 1-methylethyl, 1-methylpropyl, 1-dimethylethyl, 1-methylbutyl, 1, 2-dimethylpropyl, 1-dimethylpropyl, 1-ethylpropyl, 1-methylpentyl, 1, 2-dimethylbutyl, 1, 3-dimethylbutyl, 1, 2-trimethylpropyl, 1, 2, 2-trimethylpropyl, 1-ethylbutyl, 1-ethyl-2-methylpropyl, 1-methylhexyl, 1-ethylpentyl, 1-propylbutyl, 1, 3, 3-tetramethylbutyl, 1, 2, 2, 5, 5-hexamethylhexyl, C₅-C₈Cycloalkyl, such as cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl, preferably cyclohexyl, C₆-C₁₀-aryl and C₆-C₁₀-aryl-C₁-C₄Alkyl, aryl of which may be substituted by C₁-C₄Alkyl up to trisubstituted, such as phenyl, naphthyl or 2, 2-dimethylbenzyl, R³Represents hydrogen and C₁-C₄Alkyl radicals such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, preferably hydrogen and methyl.

Examples of compounds (I) which are of particular importance for the present invention are commercially available tris (2, 4-di-tert-butylphenyl) phosphite (Irgafos. TM.168, Ciby-Geigy) and tris (nonylphenyl) phosphite, preferably tris (2, 4-di-tert-butylphenyl) phosphite.

Component c₂) Refers to an amine of the general formula (II)

Wherein n represents a value of 2 to 10, preferably 2 to 8. Compounds of this type are also known under the name HALS (hindered amine light stabilizer) compounds and are commercially available.

An example of a compound (II) of particular interest for the present invention is bis (2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate (commercially available under the name Tinuvin TM 770DF (Ciba Geigy)).

Component c₃) Refers to benzotriazoles of the general formula (III)

Wherein R is⁴、R⁵And R⁶Having R¹The meaning of (a).

Examples of compounds (III) which are of particular interest for the present invention are 2- (2 ' -hydroxy-5 ' -methyl-phenyl) benzotriazole (commercially available under the name Tinuvin TM P (Ciba Geigy)) or 2- (2 ' -hydroxy-3 ' -dodecyl-5 ' -methyl-decyl) benzotriazole.

Component c₄) Refers to phenols of the following general formula (IV)

AB_k (IV)

Wherein k represents 1, 2 or 4, and if k ═ 1, a represents-COOR⁷、-CONHR⁷、

Wherein R is⁷Is represented by C₁-C₂₁-an alkyl group, and

if k is 2, then A represents-CONH- (CH)₂)_n-CONH-、

Wherein p and m represent an integer of 1 to 10, and if k is 4, a represents

Wherein q represents an integer of 1 to 4, and B represents

Wherein R is⁸And R⁹Represents hydrogen, methyl or tert-butyl.

Component c₄) May in some cases lead to a further improvement in the stress cracking resistance after weathering.

Examples of compounds (IV) of particular importance for the invention are octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (commercially available under the name Irganox TM 1076(Ciba Geigy)) and

component c₁)、c₂) And c₃) Preferably, the mixing is used to achieve a synergistic effect in terms of improvement of stress cracking resistance after weathering.

Component c₁)-c₃) The preferred amounts of (A) are in each case from 1% by weight to 50% by weight, preferably from 30% by weight to 50% by weight, based on component c₁)-c₃) The sum of the amounts of (a), wherein each amount totals 100.

Component c₄) The amount of (B) is preferably selected in the range from 0% to 25% by weight, preferably from 10% to 25% by weight, based on component c₁)-c₃) The total amount of (a).

Component c₁)-c₄) The total amount of (a) is advantageously from 0.05% to 1% by weight, preferably from 0.1% to 0.5% by weight, based on the total weight of the composition.

Colouring of the composition

According to the invention, the composition is colored. The coloring is preferably carried out here by means of a colorant which may be a dye or a pigment. The dyes preferably consist of dye molecules which are essentially molecularly dissolved in the polymer matrix or are more or less molecularly absorbed or chemically bonded to the surface. And pigments include, in particular, aggregates of dye molecules or minerals that are insoluble in the polymer matrix.

In addition, the colorant may also be insoluble in the polymer matrix at one temperature and may behave like a pigment. And at another, usually higher temperature, it can be dissolved in the same polymer matrix as the dye. However, in the present invention, those colorants in which the solubility in the polymer matrix varies by up to 10% based on the solubility at 23 ℃ in the temperature range from 23 ℃ to 100 ℃ are particularly preferred.

In the present invention, the coloration causes at least one absorption in the visible region, i.e. at least one wavelength in the range from 380nm to 750 nm. The absorption at 23 ℃ is preferably at least 1%, preferably at least 5%, in particular at least 10%, compared with a sample of the same nature without colorant.

In the present invention, the hue of the composition is described in terms of the laboratory color system. It is standardized, has equal spacing, is device independent and is based on human perception.

L^*a^*b^*The color space of the system is defined as follows:

●L^*lightness (black 0 and white 100)

●a^*Red-green (-128 green, +127 red)

●b^*Yellow-blue (-128 blue, +127 yellow)

The compositions according to the invention show an unusual colour constancy. For example, it has a Δ E of less than 0.15 at 50 ℃, where Δ E is defined according to relation (1):

in the formula

ΔL^*: representing the color coordinate L^*And color coordinate L at 23 DEG C^*Change of phase contrast

Δa^*: representing the color coordinate a^*With color coordinate a at 23 DEG C^*Change of phase contrast

Δb^*: representing color coordinates b^*With color coordinate b at 23 DEG C^*A change in the phase ratio.

At 80 ℃, Δ E is preferably less than 0.3.

The addition of additives having significantly different temperature properties of the refractive index compared to the polymer matrix, such as impact modifiers, should be avoided as far as possible, since otherwise a significant temperature dependence of the appearance can be observed.

Volume melt index MVR of the Molding Compound

In the present invention, the composition preferably has a thickness of more than 1.2cm³10min, preferably more than 1.5cm³10min, especially 1.7cm³/10min-4.0cm³A volume melt index MVR of 10min measured according to ISO 1133 at 230 ℃ and 3.8 kg.

Preparation of the composition

The compositions may be prepared via dry blending of the components, which may be present as a powder, granules or preferably pellets.

The compositions may also be processed by melting and mixing the components in the molten state or by melting a dry premix of the components to obtain a ready-to-use molding compound. This can be carried out, for example, in a single-screw or twin-screw extruder. The extrudate obtained can then be granulated. The usual additives, auxiliaries and/or fillers can be incorporated directly or subsequently, as desired, by the end user.

Processing to obtain a shaped body

The compositions according to the invention are suitable as starting materials for the production of shaped bodies having improved chemical and stress crack resistance. The shaping of the compositions can be carried out in a manner known per se, for example by processing via the viscoelastic state, i.e. by kneading, rolling, calendering, extrusion or injection molding, extrusion and injection molding, in particular injection molding, being particularly preferred according to the invention.

The injection moulding of the composition can be carried out in a manner known per se at temperatures of from 220 ℃ to 260 ℃ (mass temperature) and preferably at mould temperatures of from 60 ℃ to 90 ℃.

The extrusion is preferably carried out at a temperature of 220 ℃ to 260 ℃.

Shaped body

The shaped bodies obtainable in this way are characterized in that they have a Δ E of less than 0.15, particularly preferably less than 0.11, at 50 ℃ and a Δ E of less than 0.3, particularly preferably less than 0.2, at 80 ℃.

The Vicat softening temperature of the shaped bodies according to ISO 306-B50 is advantageously at least 109 ℃ and preferably at least 112 ℃.

The nominal elongation at break of the shaped bodies according to ISO 527 should preferably be at least 3.0%, particularly preferably 3.2%.

The modulus of elasticity according to ISO 527 of the shaped bodies is advantageously greater than 3200MPa, preferably 3500 MPa.

In addition, particularly suitable shaped bodies have a normalized stress cracking resistance factor of more than 0.80 at an outer edge fiber elongation of 1% after 30 minutes in a stress cracking resistance test according to the ESCR method.

Use of

The shaped bodies according to the invention can be used in particular as coatings, coatings or films. The injection-molded bodies can be used as parts of household appliances, communication equipment, hobby equipment or sports equipment, as body parts or as parts of body parts in the construction of automobiles, boats or airplanes. Typical examples of a fuselage part or a part of a fuselage part of an automobile are, for example, spoilers, cladding (Blenden), roof modules or exterior mirror housings.

Detailed Description

Examples

The invention will be illustrated in more detail below by means of examples, without wishing to restrict the inventive concept by them.

The following components a1), a2), b) and/or c) are used in the polymer matrix.

The following are used as component a 1): a commercially available copolymer of 75% by weight of methyl methacrylate, 15% by weight of styrene and 10% by weight of maleic anhydride has a solution viscosity in chloroform at 25 ℃ according to ISO1628-6 of 68 ml/g.

The following are used as component a 2): a commercially available copolymer of 99% by weight of methyl methacrylate and 1% by weight of methyl acrylate having a solution viscosity in chloroform at 25 ℃ of about 72ml/g (ISO 1628-part 6).

Preparation of component b):

1.9g of tert-butyl perneodecanoate and 0.85g of tert-butyl peroxy-3, 5, 5-trimethylhexanoate as polymerization initiator and 19.6g of 2-mercaptoethanol as molecular weight regulator and 4.3g of palmitic acid were admixed to a monomer mixture comprising 6355g of methyl methacrylate, 1271g of styrene and 847g of maleic anhydride.

The resulting mixture was filled into a polymerization chamber and degassed for 10 minutes. Thereafter, polymerization was carried out in a water bath at 60 ℃ for 6 hours, and then at a water bath temperature of 55 ℃ for 30 hours. After about 30 hours, the polymerization mixture reached its maximum temperature at 126 ℃. After removal of the polymerization chamber from the water bath, the polymerization product was further treated in the polymerization chamber at 117 ℃ for 7 hours at reduced temperature in an air oven.

The resulting copolymer was clear and almost colorless and had V.N of 48.7ml/g (solution viscosity according to ISO1628-6, 25 ℃, chloroform). The flowability of the copolymer was determined according to ISO 1133 at 230 ℃ and 3.8kg, giving an MVR of 3.27cm³/10min。

Component b)Thus a copolymer formed from 75 wt% methyl methacrylate, 15 wt% styrene and 10 wt% maleic anhydride.

The following substances are used asComponent c): a commercially available copolymer formed from 99% by weight of methyl methacrylate and 1% by weight of methyl acrylate has a solution viscosity in chloroform at 25 ℃ of about 53ml/g (ISO 1628-part 6).

Available from Dow Plastics Inc905UV was used as SAN copolymer.

A dry blend was prepared from the components using a tumble mixer and then compounded on a Leistritz LSM30/34 twin screw extruder.

The compositions of the various examples are reported in table 1.

Table 1:

the volume flow index MVR is determined (test standard ISO 1133: 1997).

Tensile bars and injection-molded sheets were produced from all materials on an injection-molding machine Battenfeld BA 350CD and their properties were tested by the following methods:

vicat (16h/80 ℃ C.): determination of the Vicat softening temperature (test Standard DIN ISO 306: 8 months 1994)

Modulus of elasticity: determination of the modulus of elasticity (test Standard: ISO 527-2)

Tensile strength: determination of the elongation at break (test Standard: ISO 527)

Δ E: measuring a 3mm injection molding sheet; measuring instrument Color Eye 7000A, Mac Beth corporation; standard DIN 5033, DIN 6174

Stress crack formation (ESCR):

all samples were stored at 23 ℃/50% relative humidity for at least 24h prior to testing.

In an ESCR test according to professor Bledzki (a. Bledzki, c.barth, material ruffing [ materials test ]40, 10(1998)), a temporally constant outer edge fiber elongation was applied using a three-point bending arrangement. The test pieces (dimensions 80 mm. times.20 mm. times.d, thickness d. 4mm) were placed flat on two supports at a spacing L of 64 mm.

Specific experimental configurations are illustrated in figures 1 and 2.

Drawings

Fig. 1 schematically shows a three-point bending arrangement in an ESCR test.

Fig. 2 shows an ESCR test apparatus (the arrangement of fig. 1 is reversed here). The cylindrical support and the pressure ram (druckfine) have a radius of 10 mm.

The necessary lower deflection s (on the side opposite the press ram in the middle of the test piece) at a given outer edge fiber elongation epsilon is calculated as in ISO 178 according to the following equation:

(2)

adjusted by a knurled screwA deflection s. ε was adjusted to a value of 1%. Fiber elongation at approach to outer edge (time point T)₀) Thereafter, a hold time of 2min is waited for the first relaxation phenomenon. At T ═ T₁In the case of 2min, the medium (isopropanol) is used to wet a piece of a size 50X 10mm which has been placed on top beforehand in the middle²The filter paper of (1). From T₁The force required to maintain the outer edge fiber elongation as a function of time was initially measured. The filter paper was always kept wet with the medium during the measurement. When the test piece fails (force 0), but the measurement is terminated at the latest after 30 min.

This procedure was repeated for three test pieces. For comparison, force traces were also recorded for test pieces that were not exposed to the media, although experiencing the same peripheral fiber elongation. In the case of the samples without medium influence, the measured force values slowly decrease, while the samples tested under medium influence show a faster force drop, depending on the resistance.

Time-dependent measurement of stress cracking resistance E_T ^normThe force F required to maintain the elongation of the outer edge fiber in this experiment_T ^mMAnd F without medium influence_T ^oMThe ratio of (A) to (B) is obtained:

(3)

here, the forces are also based on their presence at T₁Value of time such that at time point T₁：E_T ^norm1. For each test piece affected by the medium, three curves are obtained in the figure. The reference is in each case the same measurement on a test piece which is not affected by the medium. Normalized ESCR factors close to 1 characterize good ESCR resistance and the passage of time T, E_T ^normA strongly reduced value of (a) characterizes a poor resistance.

The test results for the blends and the corresponding shaped parts can be seen in table 2.

Table 2:

	B1	VB1	B2	VB2	VB3
						Vicat[℃]	115.5	119	113.2	115	110.3
MVR[ml/10min]	1.9	1.9	2.9	4.5	5.2
						ESCR[mmin]	non-destructive-continuous reduction 0.92 at 30min	＞40	Non-destructive-continuous reduction 0.85 at 30min	0.08-0.42	2.6-3.9
Modulus of elasticity [ MPa]		3600	3702	3500
						Elongation at break [% ]]		3.5	3.4	3.1

Claims (52)

1. A colouring composition comprising, in each case based on the total weight of the composition:

A) from 50.0% to 99.5% by weight of at least one (meth) acrylate polymer, and

B) 0.5% to 50.0% by weight of at least one copolymer obtained by polymerizing a monomer mixture comprising:

from 70% by weight to 92% by weight of vinylaromatic monomers, and

ii.8% to 30% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

iii 0% to 22% by weight of at least one further monomer,

characterized in that said composition exhibits a Δ E of less than 0.15 at 50 ℃, wherein Δ E is defined according to relation (1):

wherein

ΔL^*: representing the color coordinate L^*And color coordinate L at 23 DEG C^*Change of phase contrast

Δa^*: representing the color coordinate a^*With color coordinate a at 23 DEG C^*Change of phase contrast

Δb^*: representing color coordinates b^*With color coordinate b at 23 DEG C^*The change in the phase ratio is such that,

and the composition contains at least one (meth) acrylate polymer a) having a solution viscosity in chloroform at 25 ℃ according to ISO 1628-part 6 of more than 55ml/g and the Vicat softening temperature VET according to ISO 306-B50 of a shaped body made from the composition is at least 109 ℃.

2. Composition according to claim 1, characterized in that the (meth) acrylate polymer is a (meth) acrylate copolymer.

3. Composition according to claim 1, characterized in that the (meth) acrylate polymer a) has a solution viscosity in chloroform at 25 ℃ according to ISO 1628-part 6 of greater than or equal to 65 ml/g.

4. Composition according to claim 2, characterized in that the (meth) acrylate polymer a) has a solution viscosity in chloroform at 25 ℃ according to ISO 1628-part 6 of greater than or equal to 65 ml/g.

5. Composition according to claim 1, characterized in that the copolymer B) is obtained by polymerizing a monomer mixture comprising:

from 75% by weight to 92% by weight of vinylaromatic monomers, and

from 18% to 25% by weight of acrylonitrile or methacrylonitrile or mixtures thereof.

6. Composition according to claim 2, characterized in that the copolymer B) is obtained by polymerizing a monomer mixture comprising:

from 75% by weight to 92% by weight of vinylaromatic monomers, and

from 18% to 25% by weight of acrylonitrile or methacrylonitrile or mixtures thereof.

7. Composition according to claim 3, characterized in that the copolymer B) is obtained by polymerizing a monomer mixture comprising:

from 75% by weight to 92% by weight of vinylaromatic monomers, and

from 18% to 25% by weight of acrylonitrile or methacrylonitrile or mixtures thereof.

8. Composition according to claim 4, characterized in that the copolymer B) is obtained by polymerizing a monomer mixture comprising:

from 75% by weight to 92% by weight of vinylaromatic monomers, and

from 18% to 25% by weight of acrylonitrile or methacrylonitrile or mixtures thereof.

9. Composition according to any one of claims 1 to 8, characterized in that the (meth) acrylate polymer a) is a copolymer of methyl methacrylate, styrene and maleic anhydride.

10. Composition according to claim 9, characterized in that the (meth) acrylate polymer a) is a copolymer of the following monomers:

50-90% by weight of methyl methacrylate,

from 10% to 20% by weight of styrene, and

5-15% by weight of maleic anhydride.

11. Composition according to claim 9, characterized in that it contains the (meth) acrylate polymer a) in an amount of at least 75% by weight, based on the total weight of all (meth) acrylate polymers.

12. Composition according to claim 10, characterized in that it contains the (meth) acrylate polymer a) in an amount of at least 75% by weight, based on the total weight of all (meth) acrylate polymers.

13. Composition according to any of claims 1 to 8, characterized in that the (meth) acrylate polymer a) is a homopolymer or copolymer formed from at least 80% by weight of methyl methacrylate and optionally up to 20% by weight of other monomers copolymerizable with methyl methacrylate.

14. Composition according to claim 13, characterized in that the (meth) acrylate polymer a) is a copolymer of 95% to 99.5% by weight of methyl methacrylate and 0.5% to 5% by weight of methyl acrylate.

15. Composition according to claim 13, characterized in that it also contains at least one low molecular weight (meth) acrylate polymer b) having a solution viscosity in chloroform at 25 ℃ according to ISO 1628-part 6 of less than or equal to 55 ml/g.

16. Composition according to claim 14, characterized in that it also contains at least one low molecular weight (meth) acrylate polymer b) having a solution viscosity in chloroform at 25 ℃ according to ISO 1628-part 6 of less than or equal to 55 ml/g.

17. Composition according to claim 15, characterized in that the (meth) acrylate polymer b) is a (meth) acrylate copolymer b).

18. Composition according to claim 16, characterized in that the (meth) acrylate polymer b) is a (meth) acrylate copolymer b).

19. Composition according to claim 15, characterized in that the (meth) acrylate polymer b) is a copolymer of methyl methacrylate, styrene and maleic anhydride.

20. Composition according to claim 16, characterized in that the (meth) acrylate polymer b) is a copolymer of methyl methacrylate, styrene and maleic anhydride.

21. Composition according to claim 17, characterized in that the (meth) acrylate polymer b) is a copolymer of methyl methacrylate, styrene and maleic anhydride.

22. Composition according to claim 18, characterized in that the (meth) acrylate polymer b) is a copolymer of methyl methacrylate, styrene and maleic anhydride.

23. Composition according to claim 19, characterized in that the (meth) acrylate polymer b) is a copolymer of the following monomers:

50-90% by weight of methyl methacrylate,

from 10% to 20% by weight of styrene, and

5-15% by weight of maleic anhydride.

24. Composition according to claim 20, characterized in that the (meth) acrylate polymer b) is a copolymer of the following monomers:

50-90% by weight of methyl methacrylate,

from 10% to 20% by weight of styrene, and

5-15% by weight of maleic anhydride.

25. Composition according to claim 21, characterized in that the (meth) acrylate polymer b) is a copolymer of the following monomers:

50-90% by weight of methyl methacrylate,

from 10% to 20% by weight of styrene, and

5-15% by weight of maleic anhydride.

26. Composition according to claim 22, characterized in that the (meth) acrylate polymer b) is a copolymer of the following monomers:

50-90% by weight of methyl methacrylate,

from 10% to 20% by weight of styrene, and

5-15% by weight of maleic anhydride.

27. Composition according to claim 15, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

28. Composition according to claim 16, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

29. Composition according to claim 17, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

30. Composition according to claim 18, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

31. Composition according to claim 19, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

32. Composition according to claim 20, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

33. Composition according to claim 21, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

34. Composition according to claim 22, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

35. Composition according to claim 23, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

36. Composition according to claim 24, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75% by weight

37. Composition according to claim 25, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

38. Composition according to claim 26, characterized in that the (meth) acrylate polymers a) and b) are present in the following quantitative ratios, based on the total weight of the (meth) acrylate polymers:

a)25 to 75% by weight

b)25 to 75 weight percent.

39. Composition according to any one of claims 1 to 8, 10 to 12, 14 to 38, characterized in that a lubricant is present as an adjuvant.

40. Composition according to claim 39, characterized in that stearyl alcohol is present as mould release agent.

41. Composition according to any one of claims 1 to 8, 10 to 12, 14 to 38, characterized in that it has more than 1.2cm³A volume melt index MVR of 10min measured according to ISO 1133 at 230 ℃ and 3.8 kg.

42. Composition according to any one of claims 1 to 8, 10 to 12, 14 to 38, characterized in that it is present in the form of granules.

43. The composition according to any one of claims 1-8, 10-12, 14-38, characterized in that said composition exhibits a Δ E of less than 0.3 at 80 ℃.

44. A process for producing shaped bodies, characterized in that a composition according to any of claims 1 to 43 is shaped.

45. A process according to claim 44, characterised in that the composition is extruded or injection moulded.

46. Shaped body produced by the process according to claim 44 or 45, characterized in that the shaped body exhibits a Δ E of less than 0.15 at 50 ℃.

47. Shaped body according to claim 46, characterized in that it exhibits a Δ E of less than 0.3 at 80 ℃.

48. Shaped body according to claim 46 or 47, characterized in that it has one or more of the following properties:

a. a Vicat softening temperature according to ISO 306-B50 of at least 109 ℃,

b. nominal elongation at break according to ISO 527 of at least 3.0%

c. Modulus of elasticity according to ISO 527 of greater than 3200 MPa.

49. Shaped body according to claim 46 or 47, characterized in that it has a normalized stress cracking resistance factor of more than 0.80 at 1% outer edge fiber elongation after 30 minutes in a stress cracking resistance test according to the ESCR method.

50. Shaped body according to claim 48, characterized in that it has a normalized stress cracking resistance factor at 1% outer edge fiber elongation of more than 0.80 after 30 minutes in a stress cracking resistance test according to the ESCR method.

51. Use of the shaped bodies according to any of claims 46 to 50 as semi-finished products, coatings or films.

52. Use according to claim 51 as a component of a domestic appliance, a communication device, an hobby device or a sports device and as a body part or part of a body part in the construction of a car, a boat or an airplane.