Automobile component having improved chemical resistance

Abstract

The invention relates to an automotive component comprising ≥ 90.0wt.% of a methacrylate composition with regard to the total weight of the automotive component, wherein the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition: (a) ≥ 75.0 and ≤ 98.0 wt.% of a (meth)acrylate polymer; and (b) ≥ 1.95 and ≤ 24.0 wt.%, of styrene-maleic anhydride copolymer; and (c) ≥ 0.05 and ≤ 1.0 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid; and wherein the styrene-maleic anhydride copolymer consists of ≥ 20.0 wt.% of polymeric units derived from maleic anhydride and ≤ 80.0 wt.% of polymeric units derived from a styrenic monomer, based on the total weight of the styrene-maleic anhydride copolymer; and wherein the automotive component has a haze of < 1.0 %, when determined in accordance with ASTM D 1003, 3.2 mm.

Description

24POLY0027-WO-ORD1AUTOMOBILE COMPONENT HAVING IMPROVED CHEMICAL RESISTANCEFIELD OF INVENTION

[0001] The invention relates to an automotive component comprising a methacrylate composition and to a process for preparing the automotive component. The invention further relates to an automobile comprising the automotive component and to the use of the automobile component for improving its chemical resistance especially against alcohol.BACKGROUND

[0002] Methacrylate based polymeric compositions are well-known for its advantageous properties. These advantageous properties include high transparency, hardness, weathering resistance as well as ease of processing. Methacrylate polymers are widely used in the manufacture of automotive components owing to these properties. Such automotive components / parts include tail lamp, windows and other transparent parts typically used in an automobile. However, methacrylate based polymeric compositions suffer from reduced chemical resistance especially alcohol resistance. Therefore while washing or disinfecting vehicles with such alcohol-based detergents, automobile components manufactured from methacrylate based polymeric compositions, on exposure to such detergents, develop cracks or suffer from reduced transparency.

[0003] U.S. Pat. No. 8,076,435 describes a copolymer that is produced using methyl methacrylate and tricyclodecanyl hydroxymethacrylate having a suitable balance of properties that include transparency, processability, colourability, weathering resistance and hardness. A disadvantage to this approach is that a dedicated polymerisation process and system needs to be established using these specific formulations of monomer and comonomer. This is undesirable in view of process efficiency during polymerisation. In addition, the ‘435 patent does not provide any solution for improving chemical resistance of methacrylate compositions when exposed to alcohol.

[0004] US2019 / 0169339 relates to a (meth)acrylic polymer composition. However, such a(meth)acrylic polymer composition is not directed to improving haze or chemical resistance of methacrylate compositions and points to no solution to address that problem.

[0005] Therefore, there remains a need to develop automotive components which have improved chemical resistance especially against alcohol so as to retain its optical properties. Accordingly, it is an objective of the present invention to provide for an automotive component24POLY0027-WO-ORD2 which retains its optical properties including transparency or reduced haze even after being exposed to alcohol.DESCRIPTION

[0006] Accordingly, the one or more objectives of the present invention is provided by an automotive component comprising > 90.0wt.% of a methacrylate composition with regard to the total weight of the automotive component, wherein the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition of:(a) > 75.0 and < 98.0 wt.% of a (meth)acrylate polymer; and(b) > 1.95 and < 24.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 1.0 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid; and wherein the styrene-maleic anhydride copolymer consists of > 20.0 wt.% of polymeric units derived from maleic anhydride and < 80.0 wt.% of polymeric units derived from a styrenic monomer, based on the total weight of the styrene-maleic anhydride copolymer; and wherein the automotive component has a haze of < 1.0 %, when determined in accordance with ASTM D 1003, 3.2 mm.

[0007] Advantageously, the automotive components according to the present invention, has excellent haze for example a low haze as evidenced from the value of haze less than 1.0 %, when determined in accordance with ASTM D 1003, for a sample thickness of 3.2 mm.

[0008] As the value of haze is dependent on the thickness of the sample, it may be noted that that haze values may be compared only when measured at the identical sample thickness in this instance at 3.2 mm.

[0009] Preferably, the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition of:(a) > 75.0 and < 98.0 wt.% of a (meth)acrylate polymer; and(b) > 1.95 and < 24.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 1.0 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid.24POLY0027-WO-ORD3

[0010] Advantageously, the automotive component of the present invention has excellent transparency or reduced haze. Preferably the automotive component has a haze of < 0.95 %, preferably > 0% and < 0.9 % when determined in accordance with ASTM D 1003, 3.2 mm. The term “3.2 mm” refers to the sample used for measuring haze that has a thickness of 3.2 mm.

[0011] In particular, the automotive component is able to retain its optical properties in particular its haze property even when such an automotive component is exposed to alcohol. For example, the automotive component satisfies the following equation:(Haze)at - (Haze)bt < 1.0, wherein (Haze)at is the value of haze expressed in % and determined in accordance with ASTM D1003,3.2 mm of the automotive component after chemically treating the automotive component with a 90% by volume of an alcohol solution, and (Haze)bt is the value of haze of the automotive component expressed in % and determined in accordance with ASTM D1003, 3.2 mm prior to the chemical treatment, wherein the alcohol solution is selected from ethanol solution, methanol solution or a combination of both. Accordingly, there is minimal change to haze property / transparency of the automobile component even after being exposed to alcohol.

[0012] Accordingly, in an aspect of the invention, the invention relates to an automobile comprising the automotive component of the present invention. The term automobile component as used herein means any article of manufacture that can be used in an automobile such as a tail lamp or window. Although the present invention is targeted to automotive components, the automotive components can also be used in aircraft, aerospace, railway application.

[0013] In an aspect of the invention, the invention relates to the use of the automotive component of the present invention for improving the chemical resistance against alcohol of a tail lamp or a window of an automobile.Styrene-maleic anhydride copolymer

[0014] The inventors surprisingly found that it is particularly preferred to have the styrenemaleic anhydride (SMA) copolymer to have > 20.0 wt.% of polymeric units derived from maleic anhydride, preferably > 22.0 wt.%, for the methacrylate composition to have the desired chemical resistance property against alcohol. The styrene-maleic anhydride (SMA) copolymer is derived at24POLY0027-WO-ORD4 least in part from a styrenic monomer which may include substituted or unsubstituted styrene monomer.

[0015] Preferably, the styrene-maleic anhydride copolymer consists of > 22.0 wt.% and < 35.0 wt.% of polymeric units derived from maleic anhydride and > 65.0 wt.% < 78.0 wt.% of polymeric units derived from styrenic monomer based on the total weight of the styrene-maleic anhydride copolymer. Preferably wherein the styrene-maleic anhydride copolymer consists of > 24.0 wt.% and < 30.0 wt.% of polymeric units derived from maleic anhydride and > 70.0 wt.% and < 76.0 wt.% of polymeric units derived from styrenic monomer based on the total weight of the styrene-maleic anhydride copolymer.

[0016] Further, for the purposes of the invention, the SMA copolymer not only has to have a specific lower limit on the amount of polymeric units that are derived from maleic anhydride but also the amount of SMA copolymer present in the methacrylate composition also plays a role in imparting the desired chemical resistance to the methacrylate composition. The styrene-maleic anhydride copolymer may be present in an amount of > 1.95 and < 24.0 wt.%, preferably > 4.0 and < 22.0 wt.%, preferably > 15.0 and < 22.0 wt.%, with regard to the total weight of the methacrylate composition.

[0017] The SMA copolymer may for example have an intrinsic viscosity, also referred to as IV, of> 0.20 and < 1 .00 dl / g, alternatively > 0.30 and < 0.75 dl / g, alternatively > 0.40 and < 0.60 dl / g, as determined in accordance with ISO 1628- 1 :2009. The SMA copolymer may for example have a Vicat softening temperature of > 100 C, alternatively > 120 C, alternatively^ 140 C, such as > 140 C and < 180 C, as determined in accordance with ISO 306 (2013), method B120.

[0018] The styrenic monomer of the styrene-maleic anhydride copolymer may for example be derived from styrene or any suitable substituted styrenic monomer. Preferably, the styrenic monomer is selected from styrene, vinylbenzyl chloride, a-methyl styrene, dibromostyrene, vinyltoluene, vinylxylene, butylstyrene, p-hydroxystyrene, methoxy styrene, and combination thereof. Preferably, the styrenic monomer is styrene.(Meth)acrylate polymer

[0019] Preferably, the (meth)acrylate polymer is selected from polymethylmethacrylate (PMMA), polybutylmethacrylate (PBMA), poly(methylmethacrylate-ethylacrylate) (PMMA-co- EA), polyethyl acrylate (PEA), polybenzyl methacrylate, poly(n-butyl acrylate), poly(t-butyl24POLY0027-WO-ORD5 acrylate), poly(cyclohexyl methacrylate), poly (1,3 -dimethylbutyl methacrylate), poly(3,3- dimethylbutyl methacrylate), poly(diphenylethyl methacrylate), poly(diphenylmethyl methacrylate), poly(dodecyl methacrylate), poly(2-ethylbutyl methacrylate), polyethyl methacrylate, poly(trimethylpropyl methacrylate), poly(n-propylmethacrylate), polyphenyl methacrylate, poly(l -phenylethyl methacrylate), poly octyl methacrylate, polyneopentyl methacrylate, poly(l -methylpentyl methacrylate), polymethylbutyl methacrylate, polylauryl methacrylate, polyisopropyl methacrylate, polyisopentyl methacrylate, or combinations thereof.

[0020] Preferably, the (meth)acrylate polymer is polymethylmethacrylate (PMMA).

[0021] The PMMA may have a melt flow rate as determined in accordance with ISO 1 133-1 (2011), at 230 °C using a load of 3.80 kg, of > 0.1 and < 20.0 g / 10 min, preferably > 0.5 and 10.0 g / 10 min, preferably > 1 .0 and< 5.0 g / 10 min. The use of such PMMA in the preparation of the methacrylate composition may result in a polymer composition having such flow properties allowing for the production of transparent articles of the polymer composition via injection molding.Additives

[0022] The methacrylate composition has additives comprising dyes, antioxidants, and optionally processing aid. The additives may be present in an amount of > 0.05 and < 1.0 wt.%, preferably > 0.05 and < 0.5 wt.%. Non-limiting examples of dyes that may be used include Solvent red dye 52, Solvent red dye 135. Non-limiting examples of anti-oxidants include Tri(2,4-di-t- butylphenyl)phosphite, 1.1.3-tris(2-methyl-4-hydroxy-5-t-butyl phenyl) butane, pentaerythritol tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1 ,3,5-trimethyl-2,4,6- tris(3,5-di-t-butyl- 4-hydroxybenzyl)benzene, 1 ,3,5-tris(3,5-di-t-butyl-4- hydroxybenzyl)isocyanurate, and 1 ,3,5- tris(4-t-butyl-2,6-dimethyl-3-hydroxybenzyl)isocyanurate, trisnonylphenyl phosphite, trilauryl phosphite, tris(2,4-di-t-butylphenyl)phosphite, triisodecyl phosphite, diisodecyl phenyl phosphite, diphenyl isodecyl phosphite, and triphenyl phosphite.

[0023] Preferably the processing aid is a mold releasing agent for example pentaerythritol tetrastearate.Methacrylate composition24POLY0027-WO-ORD6

[0024] Preferably, the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition, of:(a) > 77.5 and < 95.95 wt.% of a (meth)acrylate polymer; and(b) > 4.0 and < 22.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 0.5 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid.

[0025] Preferably, the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition, of:(a) > 77.5 and < 84.95 wt.% of a (meth)acrylate polymer; and(b) > 15.0 and < 22.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 0.5 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid.

[0026] Preferably, the methacrylate composition has: a) a melt flow rate (MFR) of > 1.5 and < 3.5 g / lOmin determined in accordance with ASTM D 1238, 220 °C at a load of 10kg; and b) a heat distortion temperature (HDT) of > 90.0 °C and < 110.0 °C determined in accordance with ASTM D 1238 1.82MPa, 120 °C / hr, 3.2mm.

[0027] Preferably, the automotive component has: a) a tensile stress of > 82.0 and < 90.0 MPa, when determined in accordance with ASTM D 638, 50mm / min; and b) a flexural modulus of > 3150 MPa and < 3300 MPa determined in accordance with ASTM D790, 2mm / min, 50 mm span; and c) a Notched impact of > 12.0 and < 18.0 MPa determined in accordance with ASTM D 256.

[0028] In an aspect, the invention relates to a process for preparing the automotive component according to any one of claims 1-12, the process comprising the steps of: a) dry blending the (meth)acrylate polymer, the styrene-maleic anhydride copolymer and the additives to obtain a mixture; and24POLY0027-WO-ORD7 b) drying the mixture obtained from step (a) at any temperature between 60 to 80 °C for any time between 3 to 4 hours; and c) extruding the mixture in an extruder at a maximum barrel temperature of 250 °C and at any screw speed of > 300 and < 400 rpm to obtain the automotive component.

[0029] The present invention will now be further elucidated based on the following nonlimiting examples.

[0030] Purpose - Evaluate the following methacrylate based samples for their chemical resistance against alcohol.

[0031] Material: The following compositions were considered: IE1,IE2 and IE3 are inventive samples containing methacrylate samples in accordance with the present invention. CE1 - CE5 are comparative samples.

[0032] The following material was used:Table 224POLYOQ27-WO-ORD8

[0033] Compounding and Injection molding - All samples were prepared by mixing the various additives at the proportions provided under Table 2. The various ingredients were first dry blended for 3-5 minutes in a super-floater. Thereafter the blends were pre-dried at any temperature between 60-80 °C for about 3-4hrs prior to extrusion.Table 224POLY0027-WO-ORD9

[0034] For extrusion, the blends obtained were added at the throat feeder of the extruder. Formulations were compounded on a 37mm Toshiba twin-screw. The compounds once obtained were pre-dried at 60-80°C for about 3-4hrs prior to molding. The detailed conditions of extrusion and molding are listed in Table 3 and 4.Table 3. Extrusion profile of blendsTable 4. Molding profile of compounds24POLYOQ27-WO-ORD10

[0035] Alcohol Test method: Samples obtained after molding were stored at a temperature between 70 - 80 °C for about 30 minutes prior to immersing the samples into an alcohol solution containing 90 wt.% of ethanol. Further, prior to immersing the samples in alcohol, the haze for the samples were measured. The samples were immersed in ethanol for about 15 minutes.

[0036] The samples were subsequently evaluated for optical, mechanical, and thermal, properties and reported below under Table 5.Table 5. Molding profile of compounds24POLY0027-WO-ORD11

[0037] The examples show that the samples of automotive component in accordance with the present invention is particularly resistant to damage arising from chemical degradation such as by mild oxidizing agents such as alcohol. For example, from table 5 it is evident that each of the inventive samples (IE1-IE3) not only has excellent optical property of having low haze (i.e haze of < 1.0 %) but these inventive samples (IE1-IE3) were able to retain the low haze even after being exposed to high concentration of alcohol. The technical effect of having the ability to withstand chemical degradation is of advantage as often, automotive components such as tail lamps are exposed to cleansing agents and other chemicals and the present invention enables a skilled person to design automotive components to withstand such degradation. For example, IE1-IE3 not only have excellent haze property of less than 1% but also show that the haze properties are affected minimally (i.e less than 1%) It is to be noted that CE5, was formulated using styrene-maleic anhydride copolymer having polymeric units derived from maleic anhydride of 18.0 wt.%. It is evident that such SMA copolymer grade are not suitable to impart the desired chemical resistance properties to samples prepared from it.

[0038] On the other hand, CE1 formulated having SMA copolymer content of 50.0 wt.% did not impart the desired chemical resistance even with the SMA copolymer having about 26.0 wt.% of polymeric units derived from maleic anhydride. Therefore, the SMA copolymer not only has to have the right amount of polymeric units derived from maleic anhydride but also the amount of SMA copolymer present in the methacrylate composition also plays a role in imparting the desired chemical resistance to alcohol.

[0039] From comparative examples CE3 and CE4, it is evident that alternate styrene based copolymers such as styrene acrylonitrile (SAN) is not a suitable substitute for SMA for the purpose of imparting the desired chemical resistance.

Claims

24POLY0027-WO-ORD12CLAIMS1. An automotive component comprising > 90.0wt.% of a methacrylate composition with regard to the total weight of the automotive component, wherein the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition of:(a) > 75.0 and < 98.0 wt.% of a (meth)acrylate polymer; and(b) > 1.95 and < 24.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 1.0 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid; and wherein the styrene-maleic anhydride copolymer consists of > 20.0 wt.% of polymeric units derived from maleic anhydride and < 80.0 wt.% of polymeric units derived from a styrenic monomer, based on the total weight of the styrene-maleic anhydride copolymer; and wherein the automotive component has a haze of < 1.0 %, when determined in accordance with ASTM D 1003, 3.2 mm.

2. The automotive component of claim 1, wherein the styrene-maleic anhydride copolymer consists of > 22.0 wt.% and < 35.0 wt.% of polymeric units derived from maleic anhydride and > 65.0 wt.% < 78.0 wt.% of polymeric units derived from a styrenic monomer based on the total weight of the styrene-maleic anhydride copolymer, preferably wherein the styrene-maleic anhydride copolymer consists of > 24.0 wt.% and < 30.0 wt.% of polymeric units derived from maleic anhydride and > 70.0 wt.% and < 76.0 wt.% of polymeric units derived from styrenic monomer based on the total weight of the styrene-maleic anhydride copolymer.

3. The automotive component according to any one of claims 1-2, wherein the automotive component has a haze of < 0.95 %, preferably > 0% and < 0.9 % when determined in accordance with ASTM D 1003, 3.2 mm.POLY0027-WO-ORD134. The automotive component according to any one of claims 1-3, wherein the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition, of:(a) > 77.5 and < 95.95 wt.% of a (meth)acrylate polymer; and(b) > 4.0 and < 22.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 0.5 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid.

5. The automotive component according to any one of claims 1-4, wherein the methacrylate composition comprises or consists of based on the total weight of the methacrylate composition, of:(a) > 77.5 and < 84.95 wt.% of a (meth)acrylate polymer; and(b) > 15.0 and < 22.0 wt.%, of styrene-maleic anhydride copolymer; and(c) > 0.05 and < 0.5 wt.%, of additives comprising dyes, antioxidants, and optionally processing aid.

6. The automotive component according to any one of claims 1-5, wherein the styrenic monomer is selected from styrene, vinylbenzyl chloride, a-methyl styrene, dibromostyrene, vinyltoluene, vinylxylene, butylstyrene, p-hydroxystyrene, methoxystyrene, and combination thereof.

7. The automotive component according to claim 6, wherein the styrenic monomer is styrene.

8. The automotive component according to any one of claims 1-7, wherein the (meth)acrylate polymer is selected from polymethylmethacrylate (PMMA), polybutylmethacrylate (PBMA), poly(methylmethacrylate-ethylacrylate) (PMMA-co-EA), polyethyl acrylate (PEA), polybenzyl methacrylate, poly(n-butyl acrylate), poly(t-butyl acrylate), poly(cyclohexyl methacrylate), poly (1,3 -dimethylbutyl methacrylate), poly(3,3- dimethylbutyl methacrylate), poly(diphenylethyl methacrylate), poly(diphenylmethyl methacrylate), poly(dodecyl methacrylate), poly(2-ethylbutyl methacrylate), polyethyl methacrylate, poly(trimethylpropyl methacrylate), poly(n-propylmethacrylate), polyphenyl methacrylate, poly(l -phenylethyl methacrylate), poly octyl methacrylate, polyneopentyl methacrylate, poly(l -methylpentyl methacrylate), polymethylbutylPOLY0027-WO-ORD14 methacrylate, polylauryl methacrylate, polyisopropyl methacrylate, polyisopentyl methacrylate, or combinations thereof.

9. The automotive component according to claim 8, wherein the (meth)acrylate polymer is polymethylmethacrylate (PMMA).

10. The automotive component according to any one of claims 1-9, wherein the methacrylate composition has: a) a melt flow rate (MFR) of > 1.5 and < 3.5 g / lOmin determined in accordance with ASTM D 1238, 220 °C at a load of 10kg; and b) a heat distortion temperature (HDT) of > 90.0 °C and < 110.0 °C determined in accordance with ASTM D 1238 1.82MPa, 120 °C / hr, 3.2mm.

11. The automotive component according to any one of claims 1-10, wherein the automotive component has: a) a tensile stress of > 82.0 and < 90.0 MPa, when determined in accordance with ASTM D 638, 50mm / min; and b) a flexural modulus of > 3150 MPa and < 3300 MPa determined in accordance with ASTM D790, 2mm / min, 50 mm span; and c) a Notched impact of > 12.0 and < 18.0 MPa determined in accordance with ASTM D 256.

12. The automotive component according to any one of claims 1-11, wherein the automotive component satisfies the following equation:(Haze)at - (Haze)bt < 1.0, wherein (Haze)at is the value of haze expressed in % and determined in accordance with ASTM DI 003, 3.2mm of the automotive component after chemically treating the automotive component with a 90% by volume of an alcohol solution, and (Haze)bt is thePOLY0027-WO-ORD15 value of haze of the automotive component expressed in % and determined in accordance with ASTM DI 003, 3.2mm prior to the chemical treatment, wherein the alcohol solution is selected from ethanol solution, methanol solution or combination of both.

13. A process for preparing the automotive component according to any one of claims 1-12, the process comprising the steps of: a) dry blending the (meth)acrylate polymer, the styrene-maleic anhydride copolymer and the additives to obtain a mixture; and b) drying the mixture obtained from step (a) at any temperature between 60 to 80 °C for any time between 3 to 4 hours; and c) extruding the mixture in an extruder at a maximum barrel temperature of 250 °C and at any screw speed of > 300 and < 400 rpm to obtain the automotive component.

14. An automobile comprising the automotive component according to any one of claims 1- 13.

15. Use of the automotive component according to any one of claims 1-14 for improving the chemical resistance against alcohol of a tail lamp or a window of an automobile.

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